JP2004111453A - Solar cell - Google Patents

Abstract

An object of the present invention is to reduce sunlight reflected by a solar cell and increase power generation efficiency of the solar cell.
The light condensed by the group of cylindrical condensing curved surfaces enters from a group of linear slit-shaped light transmitting holes, and is multiplexed between a photoelectric conversion layer and a light reflection layer of a solar cell element. By being reflected, the amount of light applied to the photoelectric conversion layer 2 increases, and the power generation efficiency can be increased. Further, the light-collecting element 3 and the linear slit-shaped light transmitting hole group can be adjusted so that the amount of light that is collected by the cylindrical light collecting curved surface group 4 when passing through the corresponding linear slit-shaped light transmitting hole can be adjusted. 6 are supported so as to be relatively movable.
[Selection diagram] Fig. 1

Description

【０１４０】
表１は、入射角Ｒが、−２３．４°、−２０°、−１０°、０°、１０°、２０°、２３．４°の場合において、太陽電池パネルの開放電圧Ｖと短絡電流Ｉとが最大となるように、直線スリット状光透過孔群６を有する第１透明基板１０を移動して、実施例１の太陽電池パネルの開放電圧Ｖと短絡電流Ｉを、比較例１の開放電圧Ｖと短絡電流Ｉを１００％として求めたものである。
【０１４１】
実施例１ａは、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔を、シリンドリカル状集光曲面群の焦点距離Ｆと同じ２８ｍｍとした場合の開放電圧Ｖ及び短絡電流Ｉを示しており、実施例１ｂは、集光素子３の板厚を２６ｍｍから２０ｍｍに薄くし、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔が、焦点距離Ｆよりも６ｍｍ小さい２２ｍｍとした場合の開放電圧Ｖと短絡電流Ｉを示している。
【０１４２】
実施例１ａと実施例１ｂの両方とも、開放電圧Ｖと短絡電流Ｉが１００％より大きくなっている。これは、太陽光の入射角Ｒが、−２３．４°以上２３．４°以下の範囲で変化しても、シリンドリカル状集光曲面群４により集光された太陽光が、直線スリット状光透過孔群６を通過し、光電変換層２と光反射層５との間での多重反射が実現することにより、発電効率が高くなっていることを示している。
【０１４３】
次に、実施例１ａと実施例１ｂとを比較すると、実施例１ａにおいては、入射角Ｒの絶対値が大きくなるにつれて、開放電圧Ｖと短絡電流Ｉとが相対的に小さくなっているのに対して、実施例１ｂにおいては、入射角Ｒに関係なく、相対的に大きな開放電圧Ｖと短絡電流Ｉとが得られていることがわかる。これは、実施例１ａにおいては、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔を、シリンドリカル状集光曲面群の焦点距離Ｆと同じ２８ｍｍとしたため、入射角の傾きに伴うコマ収差の発生により、直線スリット状光透過孔群６への集光特性が劣化しているのに対して、実施例１ｂにおいては、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔を、シリンドリカル状集光曲面群の焦点距離Ｆより短い２２ｍｍとすることにより、コマ収差の発生にもかかわらず、直線スリット状光透過孔群６への効率的な集光特性が実現していることによるものである。
【０１４４】
すなわち、本実施例から、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔を、シリンドリカル状集光曲面群の焦点距離Ｆより小さくすることにより、直線スリット状光透過孔群６への一層効率的な集光特性が実現し、入射角Ｒに依存しない高い発電効率を得ることができることがわかる。
【０１４５】
次に、光入射側に光反射層５が形成された上記第１透明基板１０として、粒径５μｍのＹ_２Ｏ_２Ｓ：Ｅｕ，Ｍｇ，Ｔｉの蛍光粒子を、１５体積％含有させた第１透明基板１０を用いた太陽電池を作製した。この蛍光粒子は、光電変換に利用されない波長４００ｎｍ近傍の光を、光電変換に利用される波長６００ｎｍ近傍の光に変換する。このため、蛍光粒子から発生する波長６００ｎｍ近傍の光も、光反射層５と光電変換層２との間で多重反射することにより、太陽電池の発電効率をさらに高くすることが可能となる。
【０１４６】
蛍光粒子を含有しない第１透明基板１０を用いた太陽電池と、蛍光粒子を含有した第１透明基板１０を用いた太陽電池に対して、太陽光シミュレーターを用い、１００ｍＷ／ｃｍ^２の光の入射角Ｒを変えて照射して、両者の開放電圧Ｖと短絡電流Ｉを比較した結果、蛍光粒子を含有した第１透明基板１０を用いることにより、全ての入射角Ｒにおいて、開放電圧Ｖが５〜８％大きくなり、短絡電流Ｉが１３〜１５％大きくなることが確認された。
【０１４７】
〔実施例２〕
次に、本発明の実施例２として、図１１に示す構成の太陽電池を作製した。図１及び図２に示す太陽電池においては、集光素子３と光電変換層２が形成された基板１とが固定配置され、光反射層５と直線スリット状光透過孔群６を有する第１透明基板１０が移動可能とされていたが、本実施例においては、光電変換層２が形成された基板１と第１透明基板１０とを、透明接着剤３２により接着し、発電構造体３３（図１２参照）を構成し、該発電構造体３３と集光素子３とを相対的に移動させることにより、集光素子３に対して斜めから入射した太陽光を、直線スリット状光透過孔群６へと、効率良く集光する構成となっている。
【０１４８】
この場合、図１２に示すように、図８と同様な構造を用いて、発電構造体３３と集光素子３とを相対的に移動させることにより、発電効率の高い太陽電池パネルを形成することができる。実施例２の太陽電池パネルは、実施例１の太陽電池パネルと比べて、光電変換層２が形成された基板１が固定されているか、移動しているかの違いが存在するが、その集光特性は同一であり、実施例１において示した表１と全く同様な発電効率の増大が確認された。
【０１４９】
ここで、図１２に示す構成においては、移動体である発電構造体３３から発電された電力を取り出すことが必要であるが、図５からわかるように、１年間の移動距離は、±１０ｍｍ程度の範囲内であり、可撓性を有する導電性金属板を用いることにより、安定した電力の取り出しを行うことができる。また、図８に示す実施例１の太陽電池パネルにおいては、光電変換層２を有する基板１と透明第１基板１０とが独立しており、破損を防ぐために、それぞれに強度を持たせることが必要であった。
【０１５０】
しかし、図１１および図１２に示すように、あらかじめ、光電変換層２を有する基板１と第１透明基板１０とを接着固定し発電構造体３３として、太陽電池パネルを組み立てることにより、接着固定された発電構造体３３の強度が増大される。従って、基板１および第１透明基板１０を薄くしても、発電構造体３３としての強度が大きくなり、太陽電池パネルを薄くすることが可能となる。
【０１５１】
次に、実施例２の第１透明基板１０として、実施例１と同じく、粒径５μｍのＹ_２Ｏ_２Ｓ：Ｅｕ，Ｍｇ，Ｔｉの蛍光粒子を、１５体積％含有させた第１透明基板を用いた太陽電池を作製した。実施例１と同様にして、蛍光特性を有する第１透明基板１０を用いた実施例２の太陽電池パネルの発電効率の調査を行った結果、実施例２においても、蛍光特性を有する第１透明基板１０を用いることにより、全ての入射角において、開放電圧Ｖが５〜８％大きくなり、短絡電流Ｉが１３〜１５％大きくなることが確認された。
【０１５２】
次に、実施例２の透明接着剤３２として、粒径５μｍのＹ_２Ｏ_２Ｓ：Ｅｕ，Ｍｇ，Ｔｉの蛍光粒子を１５体積％含有させた紫外線硬化樹脂を用いて、集光素子３と太陽電池素子とを接着固定した太陽電池を作成した。該透明接着剤層の厚さは、０．２ｍｍであった。この蛍光粒子が、光反射層５と光電変換層２との間に導入されたけれども、光電変換に利用されない波長４００ｎｍ近傍の光を、光電変換に利用される波長６００ｎｍ近傍の光に変換する。従って、さらに、蛍光粒子から発生する波長６００ｎｍ近傍の光が、光反射層５と光電変換層２との間で多重反射することにより、太陽電池の発電効率をさらに高くすることが可能となる。
【０１５３】
蛍光粒子を含有しない紫外線硬化樹脂を用いた太陽電池パネルと、蛍光粒子を含有した紫外線硬化樹脂を用いた太陽電池パネルとに対して、実施例１と同様にして、発電効率の調査を行った結果、蛍光粒子を含有した紫外線硬化樹脂を用いた太陽電池パネルにおいて、全ての入射角において、開放電圧Ｖが５〜８％大きくなり、短絡電流Ｉが１０〜１１％大きくなることが確認された。
【０１５４】
ここで、第１透明基板１０に蛍光粒子を含有させた場合と、透明接着剤３２に蛍光粒子を含有させた場合とを比較すると、第１透明基板１０に蛍光粒子を含有させた場合に、より大きな短絡電流が得られていることがわかる。この結果は、第１透明基板１０の板厚が１０ｍｍであるのに対して、透明接着剤３２の層厚が０．２ｍｍと薄いため、含有される蛍光粒子の量が異なることに起因している。
【０１５５】
しかし、いずれの場合も、蛍光粒子の含有量を増やすことにより、より大きな短絡電流を得ることが可能である。さらに、第１透明基板１０と透明接着剤３２の両方に蛍光粒子を含有させることによっても、より大きな短絡電流を得ることが可能である。
【０１５６】
実施例１および実施例２に記載の太陽電池においては、ステンレス製の基板１上に、電極金属層１１、多結晶Ｓｉ半導体層１２、多結晶Ｓｉ半導体層１３、多結晶Ｓｉ半導体層１４、くし型集電電極１５、導電性透明膜１６を形成した多結晶Ｓｉ太陽電池を用いたが、これに限られるものではない。光電変換層２として、非晶質Ｓｉ半導体層を用いることも可能であり、また、さらに発電効率を上げるため、多結晶Ｓｉ半導体で構成したｐｎ接合と、非晶質Ｓｉ半導体で構成したｐｉｎ接合とを積層したタンデム構造太陽電池素子を用いることも可能である。
【０１５７】
また、他に、単結晶Ｓｉ太陽電池や、ＣｕＩｎＳｅ_２、Ｃｕ（Ｉｎ，Ｇａ）（Ｓ，Ｓｅ）_２、ＣｕＧａＳｅ_２などのＣＩＳ系太陽電池等に用いられている光電変換層を用いることも可能である。
【０１５８】
また、実施例１および実施例２に記載の太陽電池においては、集光素子３として射出成形法により作製したポリカーボネート製の集光素子３を用いたが、これに限られるものではない。その他の樹脂材料として、スチレン系透明樹脂、オレフィン系透明樹脂、エチレン系透明樹脂、アクリル系透明樹脂等を用いることが可能であり、また、作製方法も射出成形法に限られるものでなく、キャスティング法や熱間成形法等を用いることが可能である。さらに、モールド法やロール成形法により作製したガラス製の集光素子３を用いることも可能である。集光素子をガラス製とすることにより、耐環境性が著しく改善され、長期使用に対しても安定して高い発電効率を維持することが可能である。
【０１５９】
また、実施例１および実施例２に記載の太陽電池においては、蛍光粒子として、粒径５μｍのＹ_２Ｏ_２Ｓ：Ｅｕ，Ｍｇ，Ｔｉの蛍光粒子を用いたが、これに限られるものではない。
【０１６０】
例えば、蛍光粒子として、粒径２〜２０μｍのＹ_２Ｏ_２Ｓ：Ｅｕ，Ｍｇ，Ｔｉの蛍光粒子を使用することにより、２００〜４５０ｎｍの波長の光を吸収し、６２５ｎｍの波長の光を放射させることが可能である。また、Ｅｒ^３＋イオンを含有した酸化フッ化物系結晶化ガラスを用いることにより、８００ｎｍ近傍の波長の光を吸収し、５５０〜６６０ｎｍの波長の光を放射させることが可能である。
【０１６１】
これら以外の蛍光材料として、酸化ストロンチウムと酸化アルミニウムからなる化合物に希土類元素のユウロピウム（Ｅｕ）とジスプロシウム（Ｄｙ）を添加したＳｒＡｌ_２Ｏ_４：Ｅｕ，Ｄｙや、Ｓｒ_４Ａｌ_１４Ｏ_２５：Ｅｕ，Ｄｙや、ＣａＡｌ_２Ｏ_４：Ｅｕ，Ｄｙや、ＺｎＳ：Ｃｕ等の蛍光材料を用いることも可能である。
【０１６２】
また、シアニン系色素、ピリジン系色素、ローダミン系色素等の有機色素を含有させることによっても、同様に、短波長の光を長波長の光に変換することが可能であり、発電効率を高くすることが可能である。
【０１６３】
さらに、これらの蛍光材料を任意の組み合わせで複数同時に用いることにより、より高い発電効率を得ることが可能である。
【０１６４】
また、実施例１及び実施例２の太陽電池においては、太陽光が、シリンドリカル状集光曲面群４により、直線スリット状光透過孔群６へと集光され、第１透明基板１０を透過して、光電変換層２と反射層５との間で、入射光が多重反射する構成であったが、直線スリット状光透過孔群６を有する第１透明基板１０を上下反転させ、太陽光が、シリンドリカル状集光曲面群４により集光され、第１透明基板１０を透過した後、直線スリット状光透過孔群６を通過し、光電変換層２と光反射層５との間で、入射光が多重反射する構成とすることも可能である。ただし、この場合、第１透明基板１０は、多重反射系の外に存在するため、蛍光特性を有する透明基板を用いても、発電効率改善の効果を得ることはできない。
【０１６５】
〔実施例３〕
本発明の実施例３として、図１３に示す構成の太陽電池を作製した。
【０１６６】
実施例３の太陽電池は、実施例１に記載のシリンドリカル状集光曲面群４を有する集光素子３と、太陽電池素子用透明基板３４の両面に、それぞれ、直線スリット状光透過孔群６を有する光反射層５、及び、光電変換層３５が形成された発電構造体とで構成されている。この場合、シリンドリカル状集光曲面群４から入射した光は、直線スリット状光透過孔群６に集光され、太陽電池素子用透明基板３４を透過し、光電変換層３５へと入射し、光電変換層３５からの反射光が、光反射層５により反射され、再度光電変換層３５へと再入射する。従って、光電変換層３５と光反射層５との間で、入射光が多重反射することにより、高い発電効率が実現する。
【０１６７】
実施例３の光電変換層３５は、図１４に示す構成であり、次のようにして作製した。
【０１６８】
板厚５ｍｍの太陽電池素子用透明ガラス基板３４上に、膜厚３０ｎｍのＳｎＯ_２透明導電層３６を反応性スパッタリングにより形成した後、遮蔽マスクを基板３４上に形成した透明導電層３６表面に装着した状態で、ＡｌＴｉ合金ターゲットを用いたスパッタリングにより、膜厚１００ｎｍのＡｌ_０．９５Ｔｉ_０．０５合金からなる、幅０．１ｍｍ、間隔５ｍｍのくし型集電電極３７を形成した。
【０１６９】
次に、ｐ型不純物ドープ半導体層であるｐ層３８、真性半導体であるｉ層３９、ｎ型不純物ドープ層であるｎ層４０がこの順に積層された非晶質Ｓｉ半導体からなる光電変換層をプラズマＣＶＤ装置による気相成長法で形成した。各半導体層は、それぞれ、ＳｉＨ_４ガス・Ｈ_２ガス・ＣＨ_４ガス・Ｂ_２Ｈ_６ガスの混合ガスを用いて気相成長した膜厚１５ｎｍのａ−ＳｉＣ：Ｈのｐ層３８、ＳｉＨ_４ガス・Ｈ_２ガスの混合ガスを用いて気相成長した膜厚１００ｎｍのａ−Ｓｉ：Ｈのｉ層３９、ＳｉＨ_４ガス・Ｈ_２ガス・ＰＨ_３ガスの混合ガスを用いて気相成長した膜厚１５ｎｍのａ−Ｓｉ：Ｈのｎ層４０とした。
【０１７０】
上記光電変換層３５を形成した後、膜厚１００ｎｍのＡｌからなる光反射効果を有する電極金属層４１をスパッタリングにより形成し、紫外線硬化樹脂を電極金属層４１上に塗布し、電極金属層４１の保護膜とした。次に、上記太陽電池用素子用透明ガラス基板３４の光電変換層３５が設けられていない面に、直線スリット状光透過孔群６に対応する遮蔽マスクを取り付けた後、ＡｌＴｉ合金ターゲットを用いたスパッタリングにより、膜厚１００ｎｍのＡｌ_０．９５Ｔｉ_０．０５合金からなる光反射層５を形成して、図１３に示す発電構造体とした。
【０１７１】
上記発電構造体と集光素子３とを用いて、図１２と同じ構成の太陽電池パネルを作製し、実施例３の太陽電池パネルとした。また、上記実施例３の太陽電池用素子用透明ガラス基板３４と光電変換層３５のみからなる太陽電池パネルを比較例３の太陽電池パネルとした。実施例３及び比較例３の太陽電池パネルを実施例１と同様に、太陽光シミュレーターを用い、１００ｍＷ／ｃｍ^２の光の入射角を変えて照射して、両者の開放電圧Ｖと短絡電流Ｉを測定した。
【０１７２】
【表２】

【０１７３】
表２は、入射角Ｒが、−２３．４°、−２０°、−１０°、０°、１０°、２０°、２３．４°の場合において、太陽電池パネルの開放電圧Ｖと短絡電流Ｉとが最大となるように太陽電池素子を移動して、実施例３の太陽電池パネルの開放電圧Ｖと短絡電流Ｉとを、比較例３の開放電圧Ｖと短絡電流Ｉを１００％として求めたものである。
【０１７４】
実施例３ａは、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔を、シリンドリカル状集光曲面群の焦点距離Ｆと同じ２８ｍｍとした場合の開放電圧Ｖ及び短絡電流Ｉを示しており、実施例３ｂは、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔が、焦点距離Ｆよりも６ｍｍ小さい２２ｍｍとした場合の開放電圧Ｖと短絡電流Ｉを示している。
【０１７５】
実施例３ａと実施例３ｂの両方とも、開放電圧Ｖと短絡電流Ｉが１００％より大きくなっている。これは、シリンドリカル状集光曲面群４により集光された太陽光が、直線スリット状光透過孔群６を通過し、光電変換層３５と光反射層５との間での多重反射が実現することにより、発電効率が高くなっていることを示している。
【０１７６】
また、実施例１の場合と同様に、実施例３ｂにおいては、入射角Ｒの増大にともなうコマ収差の発生にもかかわらず、直線スリット状光透過孔群６への効率的な集光特性が実現し、入射角Ｒが±２３．４°の場合においても、入射角Ｒが０°の場合と同程度の開放電圧と短絡電流が得られていることがわかる。
【０１７７】
すなわち、実施例３においても、実施例１と同様に、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６との間隔を、シリンドリカル状集光曲面群４の焦点距離Ｆより小さくすることにより、直線スリット状光透過孔群６への一層効率的な集光特性が実現し、入射角Ｒに依存しない高い発電効率を得ることができることがわかる。
【０１７８】
ここで、実施例１（表１）と実施例３（表２）とを比較すると、実施例１の場合、短絡電流Ｉが１４５％まで増大しているのに対して、実施例３の場合、短絡電流Ｉが１３０％程度までしか増大していないことがわかる。
【０１７９】
これは、実施例３において、太陽電池素子用透明基板３４の両面に光電変換層３５と、直線スリット状光透過孔群６を有する光反射層５とを設けたことにより、太陽電池素子用透明基板３４の一方の面に光電変換層３５を形成する際、光反射層５を形成すべき太陽電池素子用透明基板３４の他方の面における、傷発生や塵埃付着により、入射光の散乱反射と光反射層５の反射率低下が発生したことによるものである。
【０１８０】
従って、より高い発電効率を実現するためには、光電変換層２と光反射層５とを別々の基板上に形成する実施例１の構成や、別々に形成したあと接着剤で一体化する実施例２の構成が望ましい。しかしながら、実施例３の構成によれば、基板枚数を削減することができ、太陽電池パネルの低コスト化及び薄型化を実現することが可能である。
【０１８１】
実施例３においては、太陽電池用素子用透明ガラス基板３４上に、光電変換層３５を形成した後、光反射層５を形成した場合について説明したが、光反射層５を形成した後、光電変換層３５を形成することも可能である。しかしながら、光反射層５を形成した後、光電変換層３５を形成した場合、光反射層５の形成時に、光電変換層３５を形成する面に発生した傷や塵埃付着により、光電変換層３５自体の特性劣化が発生し、極端な発電効率低下につながるおそれがある。従って、実施例３において説明したように、光電変換層３５を形成した後、光反射層５を形成することが望ましい。
【０１８２】
次に、上記太陽電池素子用透明基板３４として、粒径５μｍのＹ_２Ｏ_２Ｓ：Ｅｕ，Ｍｇ，Ｔｉの蛍光粒子を、１５体積％含有させたガラス基板を用いた太陽電池を作製した。この蛍光粒子は、光電変換に利用されない波長４００ｎｍ近傍の光を、光電変換に利用される波長６００ｎｍ近傍の光に変換することが可能であり、さらに、蛍光粒子から発生する波長６００ｎｍ近傍の光が、集光素子３と太陽電池素子との間で多重反射することにより、太陽電池の発電効率を一層高くすることが可能となる。
【０１８３】
蛍光粒子を含有しない太陽電池素子用透明基板３４を用いた実施例３の太陽電池と、蛍光粒子を含有した太陽電池素子用透明基板３４を用いた実施例３の太陽電池に対して、太陽光シミュレーターを用い、１００ｍＷ／ｃｍ^２の光の入射角を変えて照射して、両者の開放電圧Ｖと短絡電流Ｉを測定した結果、蛍光粒子を含有した太陽電池素子用透明基板３４を用いることにより、全ての入射角において、開放電圧Ｖが６〜９％大きくなり、短絡電流Ｉが１３〜１５％大きくなることが確認された。
【０１８４】
実施例３においては、光電変換を行うための半導体として、ｐ型不純物ドープ半導体層であるｐ層３８、真性半導体であるｉ層３９、ｎ型不純物ドープ層であるｎ層４０がこの順に積層された非晶質Ｓｉ半導体を用いた実施例について記載しているが、実施例１及び実施例２において記載した多結晶Ｓｉ半導体を用いることも可能である。
【０１８５】
ただし、多結晶Ｓｉ半導体を用いる場合、その形成順序を入れ替えることが望ましい。すなわち、透明導電層３６上に設けたくし型集電電極３７上に、ｐ型の不純物を高濃度にドーピングした多結晶Ｓｉ半導体層、ｎ型の不純物をわずかにドーピングした多結晶Ｓｉ半導体層、ｎ型の不純物を高濃度にドーピングした多結晶Ｓｉ半導体層を順次形成した構成とすることが望ましい。
【０１８６】
また、同様に、実施例１及び実施例２において、実施例３に記載した非晶質Ｓｉ半導体を用いることも可能である。
【０１８７】
〔実施例４〕
実施例３の太陽電池においては、太陽電池素子用透明基板３４の両面に、光電変換層３５と光反射層５とをそれぞれ設けた構成としたが、実施例４の太陽電池は、図１５に示すように、太陽電池素子用透明基板３４に対しては、光電変換層３５のみを設け、実施例１と同様な第１透明基板１０を、集光素子３と太陽電池素子用透明基板３４との間に、移動可能に設けた構成である。
【０１８８】
実施例３においては、太陽電池素子用透明基板３４の両面に、光電変換層３５と、直線スリット状光透過孔群６を有する光反射層５とを設けたことにより、太陽電池素子用透明基板３４の一方の面に光電変換層３５を形成する際、光反射層５を形成すべき太陽電池素子用透明基板３４の他方の面における、傷発生や塵埃付着により、入射光の散乱反射と光反射層５の反射率低下が発生することにより、発電効率が低下するという問題があったが、実施例４に示すように、光電変換層３５と光反射層５とを、別々の基板上に形成することにより、上記問題が解消され、実施例１と同程度（１４５％）の短絡電流Ｉの増大を実現することができた。
【０１８９】
この場合、入射光７は、シリンドリカル状集光曲面群４により、直線スリット状光透過孔群６に集光され、第１透明基板１０と太陽電池素子用透明基板３４とを透過して、光電変換層３５と光反射層５との間で、入射光が多重反射することになる。従って、第１透明基板１０または太陽電池素子用透明基板３４として、実施例１と同様な蛍光特性を有する透明基板を用いることにより、発電効率を一層高めることが可能となる。
【０１９０】
実施例１においては、光電変換層２と光反射層５との間に存在する第１透明基板１０のみを蛍光特性を有する透明基板とすることにより、発電効率を高めることができた。これに対して、本実施例においては、光電変換層３５と光反射層５との間に、第１透明基板１０と太陽電池用透明基板３４とが存在しており、その両方の基板として、蛍光特性を有する透明基板を用いることが可能である。従って、第１透明基板１０と太陽電池用透明基板３４との両方で光電変換に寄与する波長の光を蛍光として発生させることが可能となり、実施例１と比較して、さらに発電効率を高めることが可能となる。
【０１９１】
また、図１５に示す構成で、直線スリット状光透過孔群６を有する第１透明基板１０を上下反転させ、太陽光が、シリンドリカル状集光曲面群４により集光され、第１透明基板１０を透過した後、直線スリット状光透過孔群６を通過し、太陽電池素子用透明基板３４を透過した後、光電変換層３５と光反射層５との間で、入射光が多重反射する構成とすることも可能である。この場合、第１透明基板１０は、多重反射系の外に存在するため、第１透明基板１０をとして蛍光特性を有する透明基板を用いても、発電効率を向上させることはできない。しかし、太陽電池素子用透明基板３４として蛍光特性を有する透明基板を用いることにより、発電効率が向上する。
【０１９２】
次に、図１６に示すように、光電変換層３５を有する太陽電池素子用透明基板３４と、光反射層５を有する第１透明基板１０とを、透明接着剤４２により接着した構成とし、第１透明基板１０と光電変換層３５を有する太陽電池素子用透明基板３４とを一体的に移動させることにより、シリンドリカル状集光曲面群４と直線スリット状光透過孔群６とを相対的に移動させることも可能である。
【０１９３】
この場合、第１透明基板１０と光電変換層３５を有する太陽電池素子用透明基板３４とが接着固定されることにより、機械的強度が高くなり、図１５に示す太陽電池パネルに比較して、第１透明基板１０と太陽電池素子用透明基板３４の基板厚を薄くすることが可能となり、太陽電池パネルを薄型化できる。
【０１９４】
また、第１透明基板１０または太陽電池素子用透明基板３４として、実施例１と同様な蛍光特性を有する透明基板を用いることにより、発電効率を高めることが可能となる。
【０１９５】
さらに、図１５の場合と同様に、第１透明基板１０と太陽電池素子用透明基板３４との両方の基板として、蛍光特性を有する透明基板を用いることにより、第１透明基板１０と太陽電池用透明基板３４との両方で光電変換に寄与する波長の光を蛍光として発生させることが可能となり、さらに発電効率を高めることが可能となる。
【０１９６】
また、実施例２と同様に、透明接着剤４２に蛍光粒子を含有させ、蛍光特性を持たせた透明接着剤４２を用いることによっても、発電効率を高めることが可能となる。さらに、第１透明基板１０と太陽電池素子用透明基板３４との両方の基板として、蛍光特性を有する透明基板を用い、かつ、蛍光特性を持たせた透明接着剤４２を用いることにより、一層高い発電効率を得ることが可能である。
【０１９７】
本発明に係る太陽電池は、図１、図１１、図１５及び図１６に示すように、上記集光曲面群が設けられた集光素子と、上記光電変換層を有する太陽電池素子との間に、第１透明基板が移動可能に設けられており、該第１透明基板上に上記光透過孔群を有する上記光反射層が設けられていることを特徴としている。
【０１９８】
上記の構成により、上記集光素子と上記第１透明基板と上記太陽電池素子とを、それぞれ、独立して形成することが可能であり、製造プロセスにおいて発生する傷等の損傷が抑制され、高い発電効率を有する太陽電池を安定して製造することができる。
【０１９９】
また、本発明に係る太陽電池は、上記の構成に加えて、上記第１透明基板と上記太陽電池素子とが、透明接着剤により固定されていることを特徴としている。
【０２００】
上記の構成により、上記の効果に加えて、上記第１透明基板と上記太陽電池素子とが、あらかじめ、接着固定されていることにより、上記第１透明基板および上記太陽電池素子の機械的強度が高められ、製造プロセスにおいて、破損等による歩留まり低下を抑制することが可能であるとともに、太陽電池の薄型化を実現することができる。
【０２０１】
また、本発明に係る太陽電池は、図１３に示すように、上記光電変換層が太陽電池素子用透明基板の一方の面に設けられており、上記太陽電池素子用透明基板の上記光電変換層に対向する面に、上記光透過孔群を有する上記光反射層が設けられていることを特徴としている。
【０２０２】
上記の構成により、上記太陽電池素子用透明基板上に、上記光電変換層と上記光反射層の両方を形成することが可能であり、必要最小限の基板枚数で、太陽電池を製造することが可能であり、太陽電池の低コスト化が実現するとともに、太陽電池の薄型化を実現することができる。
【０２０３】
また、本発明に係る太陽電池は、図１５及び図１６に示すように、上記集光素子と、上記太陽電池素子との間に第１透明基板が設けられており、該第１透明基板に、上記光透過孔群を有する上記光反射層が設けられており、上記光電変換層が太陽電池素子用透明基板上に設けられていることを特徴としている。
【０２０４】
上記の構成により、上記集光素子と上記第１透明基板と上記太陽電池素子とを、それぞれ、独立して形成することが可能であり、製造プロセスにおいて発生する傷等の損傷が抑制され、高い発電効率を有する太陽電池を安定して製造することができる。
【０２０５】
また、本発明に係る太陽電池は、上記の構成に加えて、上記第１透明基板と上記太陽電池素子とが、透明接着剤により固定されていることを特徴としている。
【０２０６】
上記の構成により、上記の効果に加えて、上記第１透明基板と上記太陽電池素子とが、あらかじめ、接着固定されていることにより、上記第１透明基板および上記太陽電池素子の機械的強度が高められ、製造プロセスにおいて、破損等による歩留まり低下を抑制することが可能である。
【０２０７】
また、本発明に係る太陽電池は、光反射層と光電変換層との間に、蛍光特性を有する透明基板が設けられていることを特徴としている。
【０２０８】
上記の構成により、光電変換に寄与する波長の光の光量が増大するので、太陽電池の発電効率を一層高くすることが可能となる。
【０２０９】
また、本発明に係る太陽電池は、上記光反射層と上記光電変換層との間の積層構造中に、蛍光特性を有する透明接着剤層が含まれていることを特徴としている。
【０２１０】
上記の構成において、光反射層と上記光電変換層との間には、透明接着剤層が介在する色々な態様の積層構造を含めることができる。例えば、集光素子の太陽電池素子側の面に光反射層を形成した集光素子を、透明接着剤層を介して太陽電池素子に接着固定してもよい。あるいは、集光素子と太陽電池素子との間隔を制御する透明基板を、透明接着剤層を介して集光素子と太陽電池素子との間に接着固定してもよい。あるいは、集光素子側の面に光反射層を形成した透明基板を、透明接着剤層を介して太陽電池素子に接着固定してもよい。
【０２１１】
上記のように、各種態様を取り得る積層構造中に、蛍光特性を有する透明接着剤層が介在することにより、太陽電池の発電効率を一層高めることができる。
【０２１２】
本発明は上述した各実施形態および実施例に限定されるものではなく、請求項に示した範囲で種々の変更が可能であり、異なる実施形態および実施例にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態および実施例についても本発明の技術的範囲に含まれる。
【０２１３】
【発明の効果】
本発明によれば、集光領域から入射した光が、光透過孔に集光され、光電変換層を有する太陽電池素子へと入射し、太陽電池素子からの反射光が、光反射層により反射され、再度太陽電池素子へと再入射する。従って、入射光が、光反射層と太陽電池素子との間で多重反射することにより、太陽電池の発電効率を高くすることが可能となる。
【０２１４】
さらに、集光領域と光透過孔とを相対的に移動可能に支持し、太陽光の入射角度に対応して、集光領域により集光された太陽光が、常に、光透過孔へと集光されるように、集光領域と光透過孔の位置を制御することにより、地軸の傾きに伴う太陽光入射角度の変化が発生するような場合においても、高い変換効率を維持することが可能な太陽電池を実現することが可能となる。
【０２１５】
また、本発明において、透明基板及び透明接着剤として、蛍光特性を有する透明基板及び透明接着剤を用いることにより、光電変換層において光電変換に使用できない波長の光を、光電変換に使用できる波長の光に変換することができるので、太陽電池の発電効率をさらに高くすることが可能となる。
【図面の簡単な説明】
【図１】本発明の太陽電池の模式的な断面斜視図である。
【図２】本発明の太陽電池において、横方向斜め上から入射する光の集光位置と、光透過孔群の位置との関係を示す模式的な断面斜視図である。
【図３】本発明の太陽電池の設置方法を説明する図面である。
【図４】本発明の太陽電池において、縦方向斜め上から入射する光の集光位置と、光透過孔群の位置との関係を示す模式的な断面斜視図である。
【図５】（ａ）〜（ｃ）は、本発明の太陽電池の集光状態を、入射角度を変えて計算した結果を示す説明図である。
【図６】（ａ）〜（ｃ）は、本発明の太陽電池において、光透過孔群を集光曲面群に近づけた場合の集光状態を、入射角度を変えて計算した結果を示す説明図である。
【図７】本発明の太陽電池素子の模式的な断面図である。
【図８】本発明の太陽電池パネルの要部断面図である。
【図９】本発明の太陽電池パネルの概略的平面図である。
【図１０】本発明の太陽電池パネルにおいて、集光素子と該光透過孔群との相対位置を制御する制御システムの構成を示すブロック図である。
【図１１】本発明の太陽電池の別構成を示す模式的な断面斜視図である。
【図１２】本発明の太陽電池パネルの別構成を示す模式的な断面図である。
【図１３】本発明の太陽電池のさらに別構成を示す模式的な断面斜視図である。
【図１４】本発明の太陽電池素子の別構成を示す模式的な断面図である。
【図１５】本発明の太陽電池のさらに別構成を示す模式的な断面斜視図である。
【図１６】本発明の太陽電池のさらに別構成を示す模式的な断面斜視図である。
【図１７】従来の太陽電池の一例を示す模式的な断面図である。
【図１８】従来の太陽電池の他の例を示す模式的な断面図である。
【図１９】従来の太陽電池のさらに他の例を示す模式的な断面図である。
【図２０】本発明に関連する太陽電池の模式的な断面斜視図である。
【図２１】（ａ）（ｂ）は、本発明に関連する太陽電池の集光状態を、入射角度を変えて計算した結果を示す説明図である。
【符号の説明】
１　基板（太陽電池素子）
２　光電変換層（太陽電池素子）
３　集光素子
４　シリンドリカル状集光曲面群（集光領域の集まり）
５　光反射層
６　直線スリット状光透過孔群
７　入射光
８　縦方向
９　横方向
１０　第１透明基板
３２　透明接着剤
３３　発電構造体
３４　太陽電池素子用透明基板
３５　光電変換層
４２　透明接着剤
Ｆ　焦点距離
Ｑ　入射角度
Ｒ　入射角度[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a solar cell.
[0002]
[Prior art]
Conventional solar cells include a polycrystalline Si solar cell that performs photoelectric conversion by a pn junction as shown in FIG. 17 (for example, see Patent Document 2), and a non-crystalline solar cell that performs photoelectric conversion by a pin junction as shown in FIG. It is a crystalline Si solar cell (for example, see Patent Document 1). Although not shown, there is a single crystal Si solar cell in which a pn junction is formed on a single crystal Si substrate.
[0003]
In the polycrystalline Si solar cell shown in FIG. 17, an electrode metal layer 172 having a light reflecting effect and a good electrical contact between the electrode metal layer 172 and the polycrystalline Si semiconductor layer 174 are provided on a substrate 171 also serving as a support. A polycrystalline Si semiconductor layer 173 doped with one of an n-type impurity and a p-type impurity at a high concentration, and a polycrystalline Si semiconductor layer 174 slightly doped with the same conductivity type impurity as the polycrystalline Si semiconductor layer 173. A polycrystalline Si semiconductor layer 175 doped at a high concentration with a conductivity type impurity opposite to the polycrystalline Si semiconductor layers 173 and 174; a current collecting electrode 176 for extracting current; and an antireflection layer 177 for efficiently capturing light. It is composed of
[0004]
In the amorphous Si solar cell shown in FIG. 18, an electrode metal layer 182 having a light reflection effect and an n-type impurity doped with an n-type impurity are formed on a substrate 181 also serving as a support. A layer 183, an i-layer 184 made of an amorphous Si semiconductor and being an intrinsic semiconductor, a p-layer 185 made of an amorphous Si semiconductor and doped with a p-type impurity, a current collecting electrode 186 for extracting a current, an efficient light And an anti-reflection layer 187 for taking in light.
[0005]
In addition, in order to increase power generation efficiency, a tandem solar cell has been proposed in which a pn junction formed of a polycrystalline semiconductor shown in FIG. 17 and a pin junction formed of an amorphous semiconductor shown in FIG. 18 are stacked.
[0006]
In addition to these solar cells, a solar cell as shown in FIG. 19 in which light is incident from the substrate side has been proposed. The solar cell includes a transparent substrate 191, an antireflection layer 192 for efficiently taking in light, a current collecting electrode 193 for taking out current, and an amorphous Si semiconductor on the transparent substrate 191 in order from the light incident side. A p-layer 194 doped with a p-type impurity; an i-layer 195 made of an amorphous Si semiconductor and being an intrinsic semiconductor; an n-layer 196 made of an amorphous Si semiconductor and doped with an n-type impurity; And an electrode metal layer 197.
[0007]
[Patent Document 1]
JP-A-5-48127 (published February 26, 1993)
[0008]
[Patent Document 2]
JP-A-11-214717 (published August 6, 1999)
[0009]
[Problems to be solved by the invention]
However, the above-described conventional configuration has a problem that power generation efficiency is low due to various factors described below.
[0010]
The first factor lies in the antireflection layers 177, 187, and 192. That is, for the purpose of minimizing surface reflection, antireflection layers 177, 187, and 192 made of a conductive transparent film are provided on the light incident surface or in the vicinity of the light incident surface, but the surface reflection is made completely zero. This is difficult, and a problem arises in that part of the incident light is reflected. In addition, the antireflection layers 177, 187, and 192 generally have wavelength dependence, and a problem arises in that the surface reflection increases when the light wavelength deviates from the center of the design wavelength. In particular, in a tandem solar cell that uses light of a relatively wide wavelength for photoelectric conversion, the adverse effect is even greater.
[0011]
The second factor is in the collecting electrodes 176, 186, 193. That is, the current collecting electrodes 176, 186, and 193 provided on the light incident side for completely extracting the current completely reflect the incident light, so that the power generation efficiency is surely reduced.
[0012]
By the way, the polycrystalline Si semiconductor layers 174 and the amorphous Si semiconductor layers 184 and 195 which generate electric charge by absorbing light and generate electric power need to have a sufficient thickness to absorb incident light. To increase the efficiency, it is conceivable to increase the film thickness. However, if the thickness of the semiconductor layer is too large, the traveling distance of the charge increases, and thus a problem arises in that the amount of current that can be extracted to the outside decreases. In addition, an increase in the thickness of the semiconductor layer leads to an increase in manufacturing time and an increase in the amount of material used, which leads to an increase in cost.
[0013]
Therefore, in order to improve the incident light absorptance of the photoelectric conversion layer including the semiconductor layer as described above, how to increase the amount of incident light on the photoelectric conversion layer without increasing the thickness of the semiconductor layer itself. This is the biggest issue. This translates into an issue of how to make it possible to reduce the thickness of the semiconductor layer without reducing external output current by using external light such as sunlight without waste. .
[0014]
The present invention has been made in order to solve the above problems, and an object of the present invention is to reduce light loss due to surface reflection from a solar cell, and furthermore, to effectively reduce light of a wider range of wavelengths in sunlight. Another object of the present invention is to provide a solar cell capable of realizing high power generation efficiency by utilizing it for photoelectric conversion.
[0015]
[Means for Solving the Problems]
The solar cell of the present invention that solves the above problems is as follows.
[0016]
The solar cell according to the present invention has a solar cell element having a photoelectric conversion layer, a light-collecting element having a light-collecting region, and a light reflecting layer having a light-transmitting hole, in order to solve the above-described problem. The light reflecting layer is configured such that light collected by the light collecting region passes through the light transmitting hole and then enters the solar cell element, and reflected light from the solar cell element is reflected by the light reflecting layer. When light that is formed between the solar cell element and the light condensing element so as to be incident again on the solar cell element and condensed by the light condensing region passes through the corresponding light transmitting hole, The light condensing element and the light reflecting layer are supported so as to be relatively movable so that the amount of light passing therethrough can be adjusted.
[0017]
With the above configuration, the light incident on the light-collecting element is condensed by the light-condensing region, passes through the light transmitting hole, and irradiates the solar cell element. In this case, a plurality of light-collecting regions and a plurality of light transmitting holes may be provided. Further, one or a plurality of light transmitting holes may be arranged at each light condensing position of the plural light condensing regions.
[0018]
Subsequently, part of the light irradiated to the solar cell element is absorbed by the photoelectric conversion layer, but part of the light is reflected on the surface or inside the solar cell element to become reflected light. On the other hand, at least a part of the reflected light is reflected by a region other than the light transmitting holes in the light reflecting layer, and is returned to the solar cell element. That is, since the reflected light is multiply reflected between the solar cell element and the reflective layer, the amount of light applied to the photoelectric conversion layer increases, so that the power generation efficiency (light use efficiency) of the solar cell is increased. It has become possible.
[0019]
Further, the light converging element and the light reflecting layer may be relatively moved so that the amount of light passing through the light transmitting hole when the light condensed by the light condensing region can be adjusted. It is possible to adjust the position of light condensed by the light condensing area with respect to the position of the light transmission hole even when the incident angle of light such as sunlight changes due to seasonal changes and time changes. It becomes possible.
[0020]
Therefore, even when the incident angle of light changes, light can efficiently pass through the light transmitting hole, and the power generation efficiency of the solar cell can be increased regardless of seasonal changes and time changes.
[0021]
In order to solve the above problems, the solar cell according to the present invention, in addition to the above-described configuration, the condensing region is a cylindrical converging curved surface, and the light transmitting hole is a linear slit-shaped light transmitting hole. In this case, the direction of the cylindrical axis of the cylindrical condensing curved surface and the extending direction of the linear slit-shaped light transmitting hole are arranged in parallel.
[0022]
In the above configuration, in order to maximize the amount of light that passes through the light transmitting hole when the light collected by the light collecting area passes through the light transmitting hole, the cross-sectional shape of the light passing through the light transmitting hole must be equal to the light transmitting hole. Has a high similarity to the shape of the light-transmitting hole, and preferably the cross-sectional area of the light is within the area of the light transmitting hole.
[0023]
According to the above configuration, since the cylindrical converging curved surface creates a linear condensing state, as a light transmitting hole, the extending direction thereof is a linear slit shape arranged in parallel with the cylindrical axis of the cylindrical converging curved surface. By adopting the light transmitting hole, the light condensed in a linear shape is efficiently condensed to the linear slit-shaped light transmitting hole.
[0024]
As a result, light incident from the linear slit-shaped light transmitting hole is multiple-reflected between the photoelectric conversion layer and the light reflection layer, and the amount of light irradiated on the photoelectric conversion layer further increases, thereby further increasing power generation efficiency. It becomes possible. Further, even when the incident angle of the sunlight changes, the incident sunlight can be efficiently condensed to the light transmitting hole.
[0025]
In addition, since the cylindrical condensing curved surface can cover an elongated condensing area, a large condensing element can be manufactured by arranging the elongated condensing areas side by side. That is, since the light-collecting element can be formed with a smaller number of light-collecting areas than the light-collecting area having a shorter shape, the structure of the light-collecting element can be simplified and the cost can be reduced. This advantage similarly applies to the formation of the light reflection layer.
[0026]
In order to solve the above-mentioned problems, the solar cell according to the present invention includes, in addition to the above configuration, a transparent substrate on which a light reflection layer having at least the light transmission hole is formed by using the light-collecting element and the solar cell element. And the transparent substrate is movable.
[0027]
With the above-described configuration, in addition to the above-described effects, the light-collecting element and the solar cell element can be hermetically sealed, and the transparent substrate disposed therebetween can be moved. It is possible to prevent rainwater and moisture from entering, and to prevent deterioration of the solar cell panel.
[0028]
Here, the transparent substrate may be fixed to the solar cell and movably disposed with respect to the light-collecting element. However, in this case, since the light-collecting element and the solar cell element cannot form a sealed structure, it is necessary to form a sealed structure of another form by fixing a cover or the like to the light-collecting element. It is.
[0029]
Therefore, the above configuration has an advantage of simplifying the closed structure.
[0030]
In order to solve the above problems, the solar cell according to the present invention, in addition to the above configuration, the light reflection layer is formed on the light incident side of the transparent substrate, and the transparent substrate is formed of the photoelectric conversion layer. It emits fluorescence having a wavelength that contributes to photoelectric conversion.
[0031]
With the above configuration, in addition to the above effects, the transparent substrate absorbs light having a wavelength that does not contribute to the photoelectric conversion of the photoelectric conversion layer, and emits light having a wavelength that contributes to the photoelectric conversion of the photoelectric conversion layer as fluorescence. As a result, the generated fluorescent light is directly or once reflected by the reflective layer, and then applied to the photoelectric conversion layer.
[0032]
Therefore, since the amount of light having a wavelength contributing to photoelectric conversion increases, the power generation efficiency of the solar cell can be further increased.
[0033]
In order to solve the above problem, the solar cell according to the present invention has, in addition to the above configuration, the light reflection layer having the light transmission holes provided between the light-collecting element and the solar cell element. Is provided, the transparent substrate and the solar cell element are fixed with a transparent adhesive, and the transparent adhesive emits fluorescence having a wavelength that contributes to photoelectric conversion of the photoelectric conversion layer. It is characterized by:
[0034]
With the above-described configuration, in addition to the above-described effects, the light-collecting element, the transparent substrate, and the solar cell element can be independently formed. Thereby, damage such as scratches generated in the manufacturing process is suppressed, and a solar cell having high power generation efficiency can be stably manufactured.
[0035]
For example, if a light reflecting layer having a light transmitting hole is provided on a surface facing the light collecting area of the light collecting element, when the light reflecting layer is formed, damage such as a scratch is generated in the light collecting area. Become. The light-collecting area determines the light-collecting performance of sunlight. When the light-collecting area is damaged, the light-collecting performance is significantly deteriorated, and the power generation efficiency is reduced.
[0036]
In addition, the surface of the solar cell element facing the photoelectric conversion layer has been damaged such as a scratch when forming the photoelectric conversion layer, and by providing a light transmitting hole on the surface where the damage exists, The condensed sunlight is scattered due to damage such as scratches, which causes a decrease in power generation efficiency.
[0037]
Further, according to the configuration, in addition to the above effects, the transparent substrate and the solar cell element are bonded and fixed in advance, so that the mechanical strength of the transparent substrate and the solar cell element is increased. In addition, in the manufacturing process, it is possible to suppress a decrease in yield due to breakage or the like, and to realize a thin solar cell.
[0038]
Further, with the above configuration, in addition to the above effects, the transparent adhesive absorbs light having a wavelength that does not contribute to the photoelectric conversion of the photoelectric conversion layer, and emits light having a wavelength that contributes to the photoelectric conversion of the photoelectric conversion layer. Is generated as fluorescent light, and the generated fluorescent light is directly or once reflected by the reflective layer, and then irradiated to the photoelectric conversion layer.
[0039]
Therefore, the amount of light having a wavelength that contributes to photoelectric conversion increases, and the power generation efficiency of the solar cell can be further increased.
[0040]
In order to solve the above problems, the solar cell according to the present invention, in addition to the above configuration, the distance between the cylindrical condensing curved surface and the light reflecting layer is longer than the focal length of the cylindrical condensing curved surface. It is characterized by being shortened.
[0041]
In the above configuration, when the solar cell is installed outdoors, the incident angle of the solar ray incident on the solar cell is accompanied by seasonal variation. The aim of the present configuration is to suppress a decrease in power generation efficiency due to this seasonal variation.
[0042]
Here, consider a state in which the cylindrical converging curved surface is placed on a horizontal surface with the convex surface facing upward, and further consider a cylinder having the cylindrical converging curved surface as a part of the cylindrical surface. In this state, the direction of rotation that rotates a vertical plane including the light beam incident from directly above the cylindrical condensing curved surface and the center line (cylindrical axis) of the cylinder around the center line is referred to as the cylindrical collection direction. It is defined as the "lateral direction" with respect to the light curved surface.
[0043]
When a light beam incident from directly above the cylindrical light-collecting curved surface is incident on the cylindrical light-collecting curved surface in a state of being inclined in the lateral direction, the light incident on the side of the cylindrical light-collecting curved surface is generated due to coma aberration. The light position is closer to the cylindrical converging curved surface than the converging focal position of the light incident on the top of the cylindrical converging curved surface. In other words, since the light condensing position differs depending on the light incident position, the light condensing state deteriorates.
[0044]
Therefore, when the light reflection layer is disposed at a position corresponding to the focal length of the cylindrical light-collecting element, light incident on the top of the cylindrical light-collecting curved surface passes through the linear slit-shaped light transmitting hole, but is cylindrical. Light incident on the side of the curved light-condensing surface is less likely to pass through the linear slit-shaped light transmitting hole, and the power generation efficiency is reduced accordingly.
[0045]
On the other hand, the cylindrical condensing curved surface and the light reflecting layer are arranged such that the distance between the cylindrical condensing curved surface and the light reflecting layer is shorter than the focal length of the cylindrical condensing curved surface. By arranging, the position of the linear slit-shaped light transmitting hole formed in the light reflection layer and the light condensing position of the light incident on the side of the cylindrical condensing curved surface are close to each other. As a result, light incident on the side of the cylindrical condensing curved surface is more likely to pass through the linear slit-shaped light transmitting hole. The light incident on the top of the cylindrical condensing curved surface passes through the straight slit-shaped light transmitting hole without change even if the position of the light reflecting layer changes in the optical axis direction.
[0046]
This makes it possible to efficiently condense the light incident on the top of the cylindrical condensing curved surface and the light incident on the side into the linear slit-shaped light transmitting hole efficiently, and the incidence of light such as sunlight High power generation efficiency can be obtained even when the angle changes.
[0047]
The configuration described in the present invention may be arbitrarily combined with each configuration described in the invention as needed.
[0048]
In order to solve the above problem, the solar cell according to the present invention, in addition to the above configuration, includes a cylindrical axis direction of the cylindrical condensing curved surface, and a plane perpendicular to the condensing element has an east-west direction. It is characterized by being installed to face.
[0049]
With the above configuration, in the morning and evening, when sunlight is incident on the cylindrical condensing curved surface from obliquely above in the east-west direction, a plane including the optical axis and including the cylindrical axis, and a plane provided with the condensing element Can always be constant, and light condensed linearly by the cylindrical converging curved surface is always converged on a plane that includes the optical axis and includes the cylindrical axis. .
[0050]
Further, according to the configuration described above, since the direction of the cylindrical axis of the cylindrical condensing curved surface and the extending direction of the linear slit-shaped light transmitting hole are arranged in parallel, the linear slit-shaped light transmitting hole is It is arranged on a plane including the optical axis and including the cylindrical axis.
[0051]
Accordingly, the sunlight can be efficiently transmitted through the linear slit light without moving the cylindrical condensing curved surface and the linear slit light transmission hole relatively in response to the change of the incident angle of the sunlight in one day. It becomes possible to condense light to the hole.
[0052]
The configuration described in the present invention may be arbitrarily combined with each configuration described in the invention as needed.
[0053]
The solar cell according to the present invention, in order to solve the above-described problems, in addition to the above configuration, a light-collecting element having the cylindrical light-collecting curved surface, and a light reflecting layer having the linear slit-shaped light transmitting hole, However, it is characterized by being supported so as to be relatively movable in the north-south direction.
[0054]
According to the above configuration, in addition to the above effects, the cylindrical converging curved surface and the linear slit-shaped light correspond to the change in the incident angle of sunlight generated due to the inclination of the earth axis due to the seasonal change. By relatively moving the transmission hole, the sunlight can be efficiently condensed to the linear slit-shaped light transmission hole, and high power generation efficiency can be obtained in all seasons.
[0055]
The configuration described in the present invention may be arbitrarily combined with each configuration described in the invention as needed.
[0056]
In order to solve the above problem, the solar cell according to the present invention has, in addition to the above configuration, an installation angle of the solar cell, in the middle of the spring or autumn equinox, a solar incident angle on the solar cell is 0 °. It is characterized by being installed so that it becomes.
[0057]
When the installation angle of the solar cell of the present invention is, for example, set so that the incident angle with respect to the solar cell is 0 ° during the middle of the summer solstice, the incident angle is twice as large as the inclination of the earth axis during the south of the winter solstice. (46.8 °), and the light-collecting characteristics are degraded due to the increase in coma due to the increase in the incident angle, and the power generation efficiency in winter is reduced.
[0058]
On the other hand, according to the above configuration, in the summer solstice and the winter solstice when the sunlight incident angle on the solar cell of the present invention is the maximum, the sunlight incident angle is the same as the inclination of the earth axis (± 23.4 °). And the incident angle does not increase any more. Therefore, coma is suppressed by reducing the change in the incident angle due to the seasonal change, and the change in the power generation efficiency due to the seasonal change can be reduced.
[0059]
The configuration described in the present invention may be arbitrarily combined with each configuration described in the invention as needed.
[0060]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the solar cell of the present invention will be described in detail with reference to the drawings.
[0061]
(Example of configuration as a premise of the present invention)
FIG. 20 is a cross-sectional perspective view of a solar cell filed by us in Japanese Patent Application No. 2001-296409 (not disclosed at the time of confirmation before the present application). The solar cell includes a solar cell element in which a photoelectric conversion layer 2 is provided on a substrate 1 also serving as a support, and a light reflecting layer 5 having a cylindrical condensing curved surface group 4 and a linear slit light transmitting hole group 6. And the light-collecting element 3 provided.
[0062]
In the solar cell shown in FIG. 20, a group of cylindrical light-converging curved surfaces 4 is formed on the light-incident side surface of the light-collecting element 3, and a light-reflecting layer 5 is formed on the light-emitting side surface of the light-collecting element 3. ing.
[0063]
In the group of cylindrical light-collecting curved surfaces 4, the convex surface of each cylindrical light-collecting curved surface faces the light incident side, and a plurality of cylindrical light-collecting curved surfaces are arranged in parallel with their respective cylindrical axes parallel. Further, the linear slit-shaped light transmitting hole group 6 is constituted by linear slit-shaped light transmitting holes corresponding to the individual cylindrical condensing curved surfaces. Further, from the viewpoint that light condensed linearly on the cylindrical condensing curved surface passes through the linear slit light transmitting hole most efficiently, the direction of the cylindrical axis of the cylindrical condensing curved surface, The linear slit-shaped light transmitting holes are arranged so that the extending direction is parallel to the extending direction.
[0064]
Here, in FIG. 20, a corresponding linear slit-shaped light transmitting hole is provided on the optical axis of the light incident from directly above the cylindrical condensing curved surface at a position where the light is condensed. Are located.
[0065]
Incident light 7 perpendicularly incident on the cylindrical converging curved surface group 4 is linearly condensed by the cylindrical converging curved surface group 4 on the linear slit-shaped light transmitting hole group 6 and is converted into the photoelectric conversion layer 2 of the solar cell element. Irradiated to The reflected light from the photoelectric conversion layer 2 is reflected by the light reflection layer 5 provided on the light-collecting element 3 and again enters the photoelectric conversion layer 2 of the solar cell element. As described above, the light incident from the linear slit-shaped light transmitting hole group 6 is multiple-reflected between the solar cell element and the light reflection layer 5, that is, by repeating absorption and partial reflection in the solar cell element. In addition, the power generation efficiency of the solar cell element can be increased.
[0066]
Therefore, the light reflecting layer 5 only needs to be able to reflect at least the reflected light from the photoelectric conversion layer 2 in a region other than the linear slit light transmitting hole group 6. The facing surface may be any light reflecting layer 5 that can reflect light.
[0067]
On the other hand, the surface on the light incident side of the light reflecting layer 5, that is, the surface facing the cylindrical condensing curved surface group 4, may have a light reflecting function or a light absorbing function. However, in order to have a light absorbing function, it is necessary to add a layer having a light absorbing function, which leads to an increase in cost. Therefore, it is desirable that the configuration in which the light reflecting layer 5 is formed only of a material having light reflectivity, that is, the light incident side surface of the light reflecting layer 5 also has a light reflecting function.
[0068]
Further, here, the description has been made using the cylindrical condensing curved surface as the condensing element having the condensing region. However, it is sufficient that the condensing element has a function of condensing light on the linear slit-shaped light transmitting hole group 6. It is not limited to this. For example, FIG. 20 shows a light-collecting element in which cylindrical condensing curved surfaces having the same radius of curvature are always arranged in parallel, but the radius of curvature gradually decreases from the top to the side of the cylindrical condensing curved surface. By using such a cylindrical condensing curved surface, it is possible to reduce coma aberration generated at the side portion, and it is possible to suppress a decrease in power generation efficiency due to an increase in the incident angle.
[0069]
In addition, it is also possible to condense light to the linear slit-shaped light transmitting hole group 6 by configuring each condensing area with a Fresnel condensing element. In this case, by using a Fresnel light-collecting element having a small unevenness, the light-collecting element can be made thinner, and the solar cell can be made thinner.
[0070]
Further, as the photoelectric conversion layer 2, a photoelectric conversion layer such as a polycrystalline Si solar cell, an amorphous Si solar cell, or a tandem-structure solar cell as described in the related art can be used.
[0071]
However, as a result of intensive studies, in the above-mentioned solar cell, when the incident angle of sunlight changes with time or season, a part or part of sunlight collected linearly by the cylindrical condensing curved surface group 4 It became clear that all of them did not pass through the linear slit light transmitting hole group 6.
[0072]
That is, as shown in FIG. 20, when the incident light 7 is incident at an incident angle R from an obliquely upper side in the horizontal direction 9 of the cylindrical condensing curved surface group 4, the optical axis is inclined, so that the power generation efficiency is significantly reduced. Was confirmed. This is because the condensed incident light 7 does not pass through the linear slit-shaped light transmission hole group 6 but is condensed on the light reflection layer 5 and is reflected by the light reflection layer 5, and the This is because sunlight is not irradiated to the photoelectric conversion layer 2.
[0073]
Here, in the present specification, as in the solar cell shown in FIG. 20, the major axis direction of the cylindrical condensing curved surface group 4 is referred to as a vertical direction 8, and a direction perpendicular to the vertical direction 8, that is, a cylindrical The direction in which the light curved surface groups 4 are arranged is referred to as a lateral direction 9.
[0074]
FIG. 21 shows a case where the refractive index n1 of air is 1.0, the refractive index n2 of the light-collecting element 3 is 1.5, and the group of cylindrical light-converging curved surfaces 4 having a radius of curvature of 10 mm is arranged with a width per line of 12 mm. This is the result of calculation of the condensing state of sunlight for the case where The unit of the numerical scale in the figure is mm.
[0075]
When the refractive index between the light-collecting element 3 and the photoelectric conversion layer 2 is different from the refractive index n2 of the light-collecting element 3, the light transmitted through the linear slit-shaped light transmitting hole group 6 is refracted. The light transmitted through the group of slit-shaped light transmitting holes 6 all contributes to power generation, and thus does not need to be considered as a problem. Therefore, here, the calculation was performed assuming that the refractive index between the light-collecting element 3 and the photoelectric conversion layer 2 was equal to the refractive index n2 of the light-collecting element 3.
[0076]
FIG. 21A shows a calculation result of a light collecting state when the incident light 7 is vertically incident (R = 0 °) on the cylindrical light collecting curved surface group 4 of the solar cell, and FIG. (b) shows the result of calculating the light-collecting state when the incident light 7 is incident at an incident angle (R = 23.4 °) from obliquely above the horizontal direction 9.
[0077]
In the case of FIG. 21A in which the incident light 7 is vertically incident, all of the incident light 7 is condensed in the linear slit-shaped light transmitting hole group 6, whereas the incident light 7 is obliquely from above in the horizontal direction 9 In the case of FIG. 21B that enters, the condensing position of the incident light 7 shifts along the horizontal direction 9. Therefore, it can be seen that the incident light 7 is condensed on the light reflection layer 5 and is reflected by the light reflection layer 5 so that all the incident light 7 is reflected.
[0078]
(Configuration example of the present invention)
The present invention solves the above-described problems, and efficiently condenses sunlight on a group of light transmitting holes even when the incident angle of sunlight changes due to the season or time, thereby realizing high power generation efficiency. . The configuration of the solar cell of the present invention will be described below with reference to FIGS.
[0079]
As shown in FIGS. 1 and 2, the solar cell of the present invention includes a solar cell element provided with a photoelectric conversion layer 2 on a substrate 1 serving also as a support, and a condensing element having a cylindrical condensing curved surface group 4. 3 and a first transparent substrate 10 provided between the solar cell element and the light condensing element 3 and provided with a light reflection layer 5 having a linear slit-shaped light transmission hole group 6.
[0080]
Further, as an important feature of the present invention, the light-collecting element 3 and the first transparent substrate 10 are supported so as to be relatively movable in the horizontal direction 9 corresponding to the incident angle of the incident light 7. That is, the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 are supported so as to be relatively movable. Accordingly, the amount of incident light 7 condensed by the light condensing element 3 when passing through the corresponding linear slit-shaped light transmitting hole can be adjusted.
[0081]
The movable support mechanism and drive mechanism will be described later. The configuration other than the first transparent substrate 10 is basically the same as the configuration described with reference to FIG.
[0082]
For example, when the incident light 7 is incident from directly above, as shown in FIG. 1, the linear slit-shaped light transmitting hole group is located at a position where the incident light 7 is linearly condensed by the cylindrical condensing curved surface group 4. When the incident light 7 is incident from an obliquely upper side in the horizontal direction 9 at an incident angle R, the position where the incident light 7 is linearly condensed with the movement of the optical axis of the incident light 7 as shown in FIG. In order to move along the horizontal direction 9, the linear slit-shaped light transmitting hole group 6 is moved along the horizontal direction 9 corresponding to the movement of the light condensing position.
[0083]
As described above, the light-collecting element 3 and the first transparent substrate 10 are relatively moved in accordance with the incident angle R of the incident light 7 obliquely incident from above in the horizontal direction 9, and the linear collection of the incident light 7 is performed. The light position is made to coincide with the position of the linear slit light transmitting hole group 6. Accordingly, even when the incident angle of sunlight changes, the incident light 7 passing through the linear slit-shaped light transmitting hole group 6 is photoelectrically converted so that the light is efficiently collected on the linear slit-shaped light transmitting hole group 6. The layer 2 is irradiated. Then, the reflected light from the photoelectric conversion layer 2 is reflected by the light reflection layer 5 provided on the first transparent substrate 10 and enters the photoelectric conversion layer 2 again.
[0084]
As described above, the light condensed in the linear slit-shaped light transmission hole group 6 is multiple-reflected between the photoelectric conversion layer 2 and the light reflection layer 5, thereby increasing the power generation efficiency of the solar cell element. It becomes. As a result, the solar cell of the present invention can maintain higher power generation efficiency than before, regardless of the change in the incident angle of sunlight.
[0085]
In order to realize multiple reflection between the photoelectric conversion layer 2 and the light reflection layer 5, at least the surface of the light reflection layer 5 facing the photoelectric conversion layer 2 has a light reflection function. is necessary.
[0086]
As the photoelectric conversion layer 2, it is possible to use a photoelectric conversion layer such as a polycrystalline Si solar cell, an amorphous Si solar cell, or a tandem solar cell as described in the related art. In addition, a single crystal Si solar cell, CuInSe ₂ , Cu (In, Ga) (S, Se) ₂ , CuGaSe ₂ It is also possible to use a photoelectric conversion layer used in CIS-based solar cells and the like.
[0087]
Next, a method for installing a solar cell according to the present invention will be described below with reference to FIGS.
[0088]
In a solar cell using sunlight as a light source, efficient power generation needs to be performed regardless of the incident angle of sunlight. For example, as shown in FIG. 3, at 8 o'clock in the morning, sunlight enters the solar cell from obliquely above east, at 12:00 noon, the sunlight enters the solar cell from vertically above, and at 16:00 in the evening, sunlight enters the solar cell. Enters the solar cell obliquely from above the west. In order to generate power efficiently, the sunlight whose incident angle changes in the day is condensed by the cylindrical condensing curved surface group 4 and efficiently incident on the linear slit-shaped light transmitting hole group 6. It is necessary.
[0089]
In addition, since there is an inclination of the earth axis of 23.4 °, the incident angle of sunlight changes depending on the season. For example, when the solar cell of the present invention is installed so that sunlight is vertically incident on the southern part of the spring equinox and autumn equinox, the sunlight is incident at an incident angle of ± 23.4 ° on the summer solstice and the winter solstice. Will be incident.
[0090]
Here, as shown in FIG. 2, when the incident light 7 is incident at an incident angle R from obliquely above the horizontal converging curved surface group 4 in the horizontal direction 9, the plane including the optical axis and also including the cylindrical axis is incident at an angle of incidence. Since it is tilted in accordance with R, the position where the light is condensed linearly by the cylindrical converging curved surface group 4 moves along the horizontal direction 9. In the solar cell of the present invention, the position of the linear slit-shaped light transmitting hole group 6 is moved along the horizontal direction 9 in accordance with the movement of the light condensing position.
[0091]
On the other hand, as shown in FIG. 4, when the incident light 7 enters at an incident angle Q from obliquely above the vertical direction 8 of the cylindrical condensing curved surface group 4, the inclination of the plane including the optical axis and including the cylindrical axis is as follows: The position where the light is condensed linearly by the cylindrical condensing curved surface group 4 is constant irrespective of the incident angle Q and exists on the plane. Therefore, even if the position of the linear slit-shaped light transmitting hole group 6 does not move, the incident light 7 is focused on the linear slit-shaped light transmitting hole group 6, and high power generation efficiency can be maintained.
[0092]
Therefore, in the solar cell according to the present invention, as shown in FIG. 3, the cylindrical condensing curved surface group 4 of the condensing element 3 and the vertical direction 8 of the cylindrical condensing curved surface group 4 correspond to the diurnal movement of the sun. It is installed so as to match the traveling direction, that is, the east-west direction. That is, it is installed so that a plane including the cylindrical axial direction of the cylindrical condensing curved surface and perpendicular to the condensing element 3 faces the east-west direction. This makes it possible to achieve high power generation efficiency even in the morning and evening when sunlight enters obliquely from above.
[0093]
The lateral direction 9 of the solar cell of the present invention is arranged so as to coincide with the north-south direction, and the cylindrical condensing curved surface group 4 and the linear slit are formed in accordance with the change of the incident angle R of the incident light 7 with the seasonal change. By relatively moving the group of light-transmitting holes 6, a solar cell that can maintain high power generation efficiency in all seasons can be realized.
[0094]
Here, a configuration has been described in which the vertical direction 8 of the solar cell of the present invention is aligned with the east-west direction, and the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 are relatively moved in the north-south direction. It is also possible to make the vertical direction 8 of the solar cell of the present invention coincide with the north-south direction, and to move the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 relatively in the east-west direction.
[0095]
However, when the vertical direction 8 coincides with the east-west direction, the incident angle R with respect to the horizontal direction 9 changes seasonally, and the maximum value of the incident angle R in that case is determined by the inclination of the earth axis, and is at most 23. 0.4 °. Therefore, a good focusing state can be obtained by slightly moving the cylindrical focusing curved surface group 4 and the linear slit-shaped light transmitting hole group 6 relatively in the north-south direction according to the season. .
[0096]
On the other hand, when the vertical direction 8 coincides with the north-south direction, the incident angle R with respect to the horizontal direction 9 changes during the day. It is necessary to relatively move the condensing curved surface group 4 and the linear slit light transmitting hole group 6 in the east-west direction. In this case, since the incident angle of sunlight changes within a range of ± 90 °, it is necessary to further increase the relative movement amount between the cylindrical condensing curved surface group 4 and the linear slit-shaped light transmitting hole group 6. . In addition, since the cycle of the reciprocating movement is on a daily basis, the load on the moving mechanism and the power consumption are increased.
[0097]
Further, when the incident angle R of the incident light 7 with respect to the lateral direction 9 increases, the light condensed by the cylindrical condensing curved surface group 4 causes coma aberration, and a good light condensing state cannot be obtained. There is a problem that the amount of sunlight passing through the group of light-transmitting holes 6 decreases and the power generation efficiency decreases. Therefore, in the solar cell of the present invention, the vertical direction 8 coincides with the east-west direction, and the cylindrical condensing curved surface group 4 and the linear slit-shaped light transmitting hole group 6 are relatively moved in the north-south direction. Is desirable.
[0098]
Further, as a method for installing the solar cell of the present invention, the solar cell is installed such that the incident light 7 is perpendicularly incident on the solar cell at both the incident angles Q and R of 0 ° in the middle of the spring equinox or the autumn equinox. It is desirable to have been. When light is incident on the group of cylindrical condensing curved surfaces 4 obliquely from above in the horizontal direction 9, coma aberration occurs, the condensing characteristics are deteriorated, and all the incident light 7 is transmitted to the group of linear slit-shaped light transmitting holes 6. And it is difficult to collect light. By installing the solar cell of the present invention such that the incident angle becomes 0 ° during the mid-south day of the vernal equinox or autumn equinox, the mid-summer or winter solstice at which the incident angle R of the incident light 7 becomes largest is Even at the time, the incident angle R of the incident light 7 has a slope of ± 23.4 ° corresponding to the angle of the earth axis, and does not become any more than this.
[0099]
On the other hand, for example, when the solar cell of the present invention is installed such that the incident angles Q and R become 0 ° during the middle of the summer solstice, the incident angle R becomes 46.8 ° during the middle of the winter solstice, and the coma aberration increases. As a result, the power generation efficiency in winter decreases due to the deterioration of the light collection characteristics.
[0100]
Next, regarding the case where the vertical direction 8 of the solar cell of the present invention is arranged so as to coincide with the east-west direction, the result of calculating the light condensing state of the sunlight at the mid-south of the winter solstice, spring equinox and autumn equinox, summer solstice, 5 (a), 5 (b) and 5 (c). The numerical values shown in FIGS. 5A, 5B, and 5C indicate distances (unit: mm) from the origin when the center of the cylindrical condensing curved surface is taken as the origin.
[0101]
On the spring equinox and autumn equinox, as shown in FIG. 5 (b), when the solar cells are installed so that the incident angle R of sunlight becomes 0 °, at the winter solstice, as shown in FIG. 5 (a). , The incident angle R of sunlight becomes -23.4 °, and in the summer solstice, the incident angle R of sunlight becomes 23.4 ° as shown in FIG.
[0102]
Here, the calculation of the condensing state is performed by setting the refractive index n1 of air to 1.0, the refractive index n2 of the condensing element 3 and the first transparent substrate 10 to 1.5, and setting a cylindrical condensing curved surface having a radius of curvature of 10 mm. Group 4 was arranged at intervals of 12 mm in width. The refractive index between the light-collecting element 3 and the first transparent substrate 10 is different from the refractive index n2 of the light-collecting element 3, and sunlight collected from the light-collecting element 3 to the first transparent substrate 10 is Although the light is refracted, here, the calculation was performed ignoring the change in the optical path due to the refraction, assuming that the gap between the light-collecting element 3 and the first transparent substrate 10 was small. As shown in FIG. 5B, the distance between the light reflecting layer 5 having the linear slit-shaped light transmitting hole group 6 and the cylindrical condensing curved surface group 4 is the focal length of the cylindrical condensing curved surface group 4. The calculation is performed for a case where it is arranged at a position equal to F.
[0103]
In FIG. 5B in which the incident angle R is 0 °, all the incident light is condensed on the linear slit-shaped light transmitting hole group 6, and high power generation efficiency can be realized. Also, in FIGS. 5A and 5C in which the incident angles R are −23.4 ° and 23.4 °, the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 are relatively moved. By doing so, it can be seen that most of the incident light is condensed on the linear slit-shaped light transmitting hole group 6, and high power generation efficiency can be realized.
[0104]
However, in FIGS. 5A and 5C, sunlight enters obliquely upward in the horizontal direction 9 with respect to the cylindrical converging curved surface group 4, so that coma occurs and the condensing characteristics deteriorate. In order to condense all the incident light on the linear slit light transmitting hole group 6, it is necessary to increase the width of the linear slit light transmitting hole group 6. On the other hand, if the width of the linear slit-shaped light transmitting hole group 6 is too wide, sunlight to be multiple-reflected between the solar cell element and the light reflecting layer 5 is emitted from the linear slit-shaped light transmitting hole group 6. As a result, the power generation efficiency is reduced.
[0105]
On the other hand, FIGS. 6A, 6B, and 6C respectively show the distance d between the cylindrical condensing curved surface group 4 and the light reflecting layer 5 (see FIG. 6A). (B) shows a light condensing state when a light reflecting layer 5 having a linear slit light transmitting hole group 6 is provided at a position smaller than the focal length F of the cylindrical light collecting curved surface group 4 as shown in FIG. I have.
[0106]
The width of the linear slit-shaped light transmitting holes is the same as that in the case of FIG. 5, but as shown in FIG. Although not coincident with the position, it is possible to collect all the incident light after transmitting it through the linear slit-shaped light transmitting hole group 6. Also, in FIGS. 6A and 6C, as in FIG. 5, although the coma aberration occurs and the light-collecting characteristics are deteriorated, all the incident light is converted into the linear slit-shaped light transmitting hole group. It can be seen that it is possible to condense light after transmitting the light through No. 6.
[0107]
As described above, in the solar cell of the present invention, the linear slit-shaped portion is located at a position where the distance d between the cylindrical converging curved surface group 4 and the light reflecting layer 5 is smaller than the focal length F of the cylindrical converging curved surface group 4. Since the light reflection layer 5 having the light transmission hole group 6 is provided, the amount of light introduced between the light reflection layer 5 and the photoelectric conversion layer 2 can be increased. In addition, since the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 are supported so as to be relatively movable, even when sunlight enters obliquely, that is, regardless of the season, High light-collecting efficiency to the linear slit-shaped light transmitting hole group 6 is realized, and power generation efficiency can be increased.
[0108]
【Example】
[Example 1]
As Example 1 of the present invention, a solar cell having the configuration shown in FIG. 1 was manufactured.
[0109]
As shown in FIG. 7, a solar cell element composed of a substrate 1 and a photoelectric conversion layer 2 is formed on a stainless steel substrate 1 also serving as a support by a 100 nm thick Al film having a light reflection effect. _0.95 Ti _0.05 After an electrode metal layer 11 made of an alloy is formed by sputtering, a polycrystalline Si semiconductor layer 12 doped with n-type impurities at a high concentration provided for improving electrical contact between the electrode metal layer 11 and the semiconductor layer. A polycrystalline Si semiconductor layer 13 slightly doped with the same n-type impurity as the polycrystalline Si semiconductor layer 12, and a polycrystalline Si semiconductor doped heavily with a p-type impurity opposite to the polycrystalline Si semiconductor layers 12, 13. The layers 14 were sequentially formed by a plasma CVD apparatus.
[0110]
The polycrystalline Si semiconductor layer 12 is made of SiH at a substrate temperature of 250 ° C. ₄ Gas, H ₂ Gas, PH ₃ A mixed gas having an optimized gas mixing ratio was introduced into a CVD apparatus, and the gas pressure was set to 20 Pa, and a high-frequency power of 100 W was applied to form the gas. Thus, a polycrystalline Si semiconductor layer 12 with a thickness of 30 nm doped with P at a high concentration was deposited on the electrode metal layer 11.
[0111]
Next, the polycrystalline Si semiconductor layer 13 is made of SiH at a substrate temperature of 550 ° C. ₄ Gas, H ₂ Gas, PH ₃ A mixed gas having an optimized gas mixing ratio was introduced into a CVD apparatus, and a gas pressure of 50 Pa was applied thereto, and a high-frequency power of 350 W was applied to form a gas. Thus, a 300 nm-thick polycrystalline Si semiconductor layer 13 lightly doped with P was deposited on the polycrystalline Si semiconductor layer 12.
[0112]
In a conventional solar cell, the polycrystalline Si semiconductor layer 13 is a layer that absorbs light, generates electric charges, and generates power. In order to sufficiently absorb light, the thickness is usually set to 5000 nm or more and 50,000 nm or less. Is set. On the other hand, in the present invention, since the incident light from the linear slit-shaped light transmission hole group 6 is multiple-reflected between the photoelectric conversion layer 2 and the light reflection layer 5, the light is efficiently absorbed. Therefore, the thickness of the polycrystalline Si semiconductor layer 13 can be reduced. That is, high power generation efficiency can be obtained even when the film thickness is as thin as 100 nm or more and 3000 nm or less. Therefore, the time for forming the polycrystalline Si semiconductor layer 13 can be significantly reduced, and the cost of the solar cell can be reduced.
[0113]
Next, the polycrystalline Si semiconductor layer 14 is made of SiH at a substrate temperature of 350 ° C. ₄ Gas, H ₂ Gas, BF ₃ A mixed gas having an optimized gas mixing ratio was introduced into a CVD apparatus, and a gas pressure of 50 Pa was applied thereto, and a high-frequency power of 100 W was applied to form the gas. Thus, a B-doped 15-nm-thick p-type polycrystalline Si semiconductor layer 14 was deposited on the polycrystalline Si semiconductor layer 13.
[0114]
Next, the substrate 1 on which the pn junction formed of the polycrystalline Si semiconductor layers 12 to 14 was formed was attached to a sputtering apparatus, and a shielding mask corresponding to the shape of the comb-shaped current collecting electrode 15 was attached to the polycrystalline Si semiconductor layer of the substrate 1. 14 with a thickness of 100 nm using an AlTi alloy target. _0.95 Ti _0.05 A comb-shaped current collecting electrode 15 made of an alloy film and having a width of 0.1 mm and an interval of 5 mm was formed.
[0115]
Finally, In ₂ O ₃ By performing reactive sputtering in an oxygen atmosphere using a target, a conductive transparent film 16 having a thickness of 65 nm was formed on the polycrystalline Si semiconductor layer 14 and the comb-shaped current collecting electrode 15.
[0116]
On the other hand, as the light condensing element 3 shown in FIG. 1, a light condensing element made of a polycarbonate resin having a thickness of 26 mm was produced by an injection molding method. The condensing curved surface group had a configuration in which cylindrical condensing curved surface groups 4 having a curvature radius of 10 mm were arranged at intervals of 12 mm in width, and the focal length F was 28 mm.
[0117]
Next, as the first transparent substrate 10 shown in FIG. 1, a shielding mask corresponding to the linear slit-shaped light transmitting hole group 6 is mounted on a 10 mm-thick polycarbonate resin substrate, and sputtering using an AlTi alloy target is performed. As a result, a 100 nm thick Al _0.95 Ti _0.05 An alloy film was formed, and on the first transparent substrate 10, the light reflection layer 5 in which the linear slit-shaped light transmission hole groups 6 were provided at 12 mm intervals was formed. The repetition pitch of the linear slit light transmitting hole group 6 and the cylindrical condensing curved surface group 4 are made equal.
[0118]
The slit width WS of the linear slit-shaped light transmitting hole group 6 was set to 1/6 of the width W per column of the cylindrical condensing curved surface group 4 (WS = 2 mm). Here, it is desirable that the slit width WS is not less than (W / 8) and not more than (2W / 3).
[0119]
In the solar cell according to the present invention, a high power generation efficiency can be obtained even when sunlight is obliquely incident from above by moving the group of cylindrical condensing curved surfaces 4 and the group of straight slit-shaped light transmitting holes 6 relatively. However, when the incident angle of sunlight increases, a good focusing state cannot be obtained due to the occurrence of coma aberration.
[0120]
Here, when WS becomes narrower than (W / 8), the light condensing state deteriorates in the season when the incident angle of sunlight becomes large (for example, on the day of summer solstice or winter solstice), so that the linear slit-shaped light transmitting hole group 6 is formed. The ratio of sunlight that does not enter the device increases, resulting in a decrease in power generation efficiency. When WS becomes wider than (2W / 3), light to be multiple-reflected between the photoelectric conversion layer 2 and the light reflection layer 5 is emitted from the linear slit-shaped light transmission hole group 6, and the utilization efficiency of incident light And the power generation efficiency decreases.
[0121]
The solar cell element 17 including the substrate 1 and the photoelectric conversion layer 2 manufactured as described above, the first transparent substrate 10, and the light-collecting element 3 were respectively mounted as shown in FIGS. The solar cell panel was arranged. FIG. 8 shows a sectional view of the solar cell panel of the present invention, and FIG. 9 shows a plan view of the solar cell panel of the present invention.
[0122]
In FIG. 9, the group of cylindrical light-condensing curved surfaces 4 and the group of linear slit-shaped light transmitting holes 6 of the light-condensing element 3 have their extending directions (vertical direction 8 in FIG. The transparent substrate 10 was arranged so as to be perpendicular to the moving direction.
[0123]
The solar cell element 17 is fixedly arranged on a pedestal 18 of the solar cell panel, and the first transparent substrate 10 is moved horizontally with respect to the pedestal 18 through six bearings 22 provided on the pedestal 18 as shown in FIG. The light-collecting element 3 is movably supported in the direction 9, and is fixedly arranged on a fixed support portion 21 erected on the pedestal 18, and covers the entire upper surface of the pedestal 18. Although an example using six bearings 22 is shown here, the present invention is not limited to this, and four or eight bearings can be used.
[0124]
One end surface of the first transparent substrate 10 is fixed via a spring 20 to a spring supporting portion 19 fixed to the pedestal 18, and the other end surface of the first transparent substrate 10 is rotated. The rotation of the drive rotor 24 eccentrically fixed with respect to the motor 23 allows the first transparent substrate 10 to move along the horizontal direction 9 shown in FIG.
[0125]
Here, by providing the first transparent substrate 10 with the elongated oval bearing receiving portion 25 in the moving direction, the first transparent substrate 10 can be moved stably. Further, by providing the bearings 26 for supporting both end surfaces of the first transparent substrate 10 along the moving direction, the movement of the first transparent substrate 10 can be further stabilized.
[0126]
Here, the solar cell panel of the present invention is arranged such that the vertical direction 8 of the cylindrical converging curved surface group 4 coincides with the east-west direction, so that the cylindrical converging converging curved surface group 4 can be It is not necessary to move the linear slit-shaped light transmitting hole group 6 relatively. However, in order for the light condensed by the cylindrical condensing curved surface group 4 to be condensed on the linear slit light transmitting hole group 6 in all seasons, about once a day or one week. It is necessary to move the group of cylindrical condensing curved surfaces 4 and the group of linear slit-shaped light transmitting holes 6 relatively in the north-south direction about once every month or about once a month.
[0127]
When the relative movement between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is performed once a day, the change in the incident angle R of sunlight per day is as small as 0.26 °. It becomes. Therefore, by moving the cylindrical condensing curved surface group 4 and the linear slit light transmitting hole group 6 relative to each other by about 0.07 mm per day, it is possible to optimally collect the linear slit light transmitting hole group 6 on a daily basis. A light state will be obtained. However, in this case, a precise drive system capable of performing a relative movement of about 0.07 mm is required, which leads to an increase in cost of the solar cell panel.
[0128]
Next, when the relative movement between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is performed once a month, the change in the incident angle R of sunlight per month is 7.67 °. It becomes. Therefore, it is necessary to relatively move the group of cylindrical condensing curved surfaces 4 and the group of linear slit-shaped light transmitting holes 6 by about 2.0 mm every month. In this case, an optimal light-collecting state on the linear slit-shaped light transmitting hole group 6 can be obtained every month, but on the day before the relative movement, the light-condensing position of the incident light 7 is shifted by about 2.0 mm. Therefore, it is necessary to form the width of the linear slit light transmitting hole group 6 appropriately wide. From the above, in this case, a precise drive system for performing relative movement is not required, but this leads to a decrease in power generation efficiency.
[0129]
Accordingly, it is desirable that the relative movement between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is performed about once a week. In this case, the change of the incident angle R of the sunlight per week is 1.79 °, and the group of the cylindrical condensing curved surfaces 4 and the group of the linear slit-shaped light transmitting holes 6 are set to about 0. By performing relative movement by about 5 mm, an optimal light-collecting state can be obtained every week. Since the movement of the condensing position in one week is as small as about 0.5 mm, the power generation efficiency does not change even when the narrow slit-shaped light transmitting hole group 6 is used. Furthermore, it is only necessary to make a relative movement of about 0.5 mm every week, which eliminates the need for a precise drive system and can reduce the cost of the solar cell panel.
[0130]
The method for controlling the relative movement in the solar cell panel shown in FIGS. 8 and 9 will be described below with reference to the block diagram shown in FIG.
[0131]
First, ROM information such as a current date and relative position information (for example, stop position information of the rotary drive motor 23) corresponding to the current date is controlled by a month / day designation unit 27 having storage means such as a ROM (read only memory). Sent to the unit 28. Next, based on the ROM information, a drive signal for the rotary drive motor 23 is generated from the control unit 28 and sent to the motor drive unit 29. As a result, the rotary drive motor 23 rotates by a required amount.
[0132]
Thereby, the first transparent substrate 10 is fixed at a position where the relative position between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is optimized according to the date. From the solar cell panel 30, information about the amount of generated power every day is sent to the control unit 28, and based on an instruction from the control unit 28, information such as the amount of generated power is sent to the status display unit 31, and is displayed in a visual form. Is output.
[0133]
Here, the system for controlling the relative positions of the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 according to the date has been described. Therefore, a system that optimizes the relative position once a week or once a month is also possible.
[0134]
Further, in the solar cell panel, the relative position between the cylindrical condensing curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is detected, and the detected relative position and the optimal relative position based on the date are determined by the control unit 28. By constructing a system for detecting an abnormality in a solar cell panel, it is possible to perform early maintenance for an abnormality in the solar cell panel.
[0135]
Further, information on the expected value of the power generation amount corresponding to the date is stored in storage means such as the ROM, and the information is compared with the information on the actual measurement value of the power generation amount obtained every day. By constructing an abnormality detection system that issues an abnormality warning when the amount falls below a predetermined amount, early maintenance can be performed for an abnormality in the solar cell panel.
[0136]
In addition, by controlling the relative position between the cylindrical condensing curved surface group 4 and the linear slit-shaped light transmitting hole group 6 so that the actually measured value of the power generation amount becomes maximum, the maximum power generation amount can always be obtained. A possible solar panel can be realized.
[0137]
In the above-described embodiment, the light-collecting element 3 is fixed, and the first transparent substrate 10 (at least the transparent substrate on which the light reflection layer 5 having the linear slit-shaped light transmitting hole group 6 is formed) is separated from the light-collecting element 3 and the sun. The solar cell panel configured to move between the battery elements 17 has been described, but a configuration in which the first transparent substrate 10 is fixed and the light-collecting element 3 is moved is also possible. However, in order to prevent rainwater or moisture from entering the inside of the solar cell panel, the light collecting element 3 is fixed and the solar cell panel is hermetically sealed by the light collecting element 3, the pedestal 18 and the fixed support 21. It is desirable to adopt such a configuration.
[0138]
Here, the power generation efficiency of the solar cell panel of Example 1 and the power generation efficiency of the solar cell obtained by removing the light-collecting element 3 and the first transparent substrate 10 of the solar cell panel as the solar cell panel of Comparative Example 1 are as follows: 100 mW / cm using a solar simulator as a light source ² Investigation was performed by changing the angle of incidence of light.
[0139]
[Table 1]

[0140]
Table 1 shows that the open-circuit voltage V and the short-circuit current of the solar cell panel when the incident angle R is −23.4 °, −20 °, −10 °, 0 °, 10 °, 20 °, and 23.4 °. The first transparent substrate 10 having the linear slit-shaped light transmitting hole group 6 was moved so that I became the maximum, and the open-circuit voltage V and the short-circuit current I of the solar cell panel of Example 1 were compared with those of Comparative Example 1. The open-circuit voltage V and the short-circuit current I are determined as 100%.
[0141]
In Example 1a, the open-circuit voltage V and the short-circuit current I when the interval between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is 28 mm, which is the same as the focal length F of the cylindrical converging curved surface group. In Example 1b, the plate thickness of the light-condensing element 3 was reduced from 26 mm to 20 mm, and the distance between the cylindrical light-condensing curved surface group 4 and the linear slit-shaped light transmitting hole group 6 was larger than the focal length F. Also shows the open-circuit voltage V and the short-circuit current I in the case of 22 mm, which is smaller by 6 mm.
[0142]
In both Example 1a and Example 1b, the open-circuit voltage V and the short-circuit current I are larger than 100%. This is because even if the incident angle R of the sunlight changes in the range of −23.4 ° or more and 23.4 ° or less, the sunlight condensed by the cylindrical condensing curved surface group 4 is converted into the linear slit light. This indicates that the power generation efficiency is increased by the multiple reflection between the photoelectric conversion layer 2 and the light reflection layer 5 through the transmission hole group 6 and realization.
[0143]
Next, a comparison between Example 1a and Example 1b shows that in Example 1a, as the absolute value of the incident angle R increases, the open-circuit voltage V and the short-circuit current I are relatively small. On the other hand, in Example 1b, it can be seen that relatively large open-circuit voltage V and short-circuit current I were obtained irrespective of the incident angle R. This is because in Example 1a, the interval between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 was set to 28 mm, which is the same as the focal length F of the cylindrical converging curved surface group, so that the inclination of the incident angle was The condensing characteristic to the linear slit-shaped light transmitting hole group 6 is degraded due to the occurrence of coma due to the above. On the other hand, in Example 1b, the cylindrical condensing curved surface group 4 and the linear slit-shaped light transmitting By setting the distance from the hole group 6 to 22 mm shorter than the focal length F of the cylindrical condensing curved surface group, efficient condensing on the linear slit-shaped light transmitting hole group 6 despite the occurrence of coma aberration. This is because the characteristics are realized.
[0144]
That is, according to the present embodiment, the distance between the group of cylindrical converging curved surfaces 4 and the group of linear slit-shaped light transmitting holes 6 is made smaller than the focal length F of the group of cylindrical converging curved surfaces, so that the linear slit-shaped light transmitting holes are formed. It can be seen that more efficient light-collecting characteristics to the group 6 are realized, and high power generation efficiency independent of the incident angle R can be obtained.
[0145]
Next, as the first transparent substrate 10 having the light reflection layer 5 formed on the light incident side, Y having a particle size of 5 μm was used. ₂ O ₂ S: A solar cell was produced using the first transparent substrate 10 containing 15% by volume of Eu, Mg, and Ti fluorescent particles. The fluorescent particles convert light near the wavelength of 400 nm that is not used for photoelectric conversion into light near the wavelength of 600 nm that is used for photoelectric conversion. For this reason, light having a wavelength of about 600 nm generated from the fluorescent particles is also multiple-reflected between the light reflection layer 5 and the photoelectric conversion layer 2, so that the power generation efficiency of the solar cell can be further increased.
[0146]
For a solar cell using the first transparent substrate 10 containing no fluorescent particles and a solar cell using the first transparent substrate 10 containing fluorescent particles, a solar simulator was used to obtain 100 mW / cm. ² As a result of comparing the open-circuit voltage V and the short-circuit current I of the two, the first transparent substrate 10 containing the fluorescent particles was used. It was confirmed that the voltage V was increased by 5 to 8% and the short-circuit current I was increased by 13 to 15%.
[0147]
[Example 2]
Next, as Example 2 of the present invention, a solar cell having the configuration shown in FIG. 11 was manufactured. In the solar cell shown in FIGS. 1 and 2, a light-condensing element 3 and a substrate 1 on which a photoelectric conversion layer 2 is formed are fixedly arranged, and a first light-reflecting layer 5 and a linear slit-shaped light transmission hole group 6 are provided. Although the transparent substrate 10 is movable, in the present embodiment, the substrate 1 on which the photoelectric conversion layer 2 is formed and the first transparent substrate 10 are adhered with a transparent adhesive 32 to form a power generation structure 33 ( FIG. 12), and the power generation structure 33 and the light-collecting element 3 are relatively moved so that sunlight obliquely incident on the light-collecting element 3 can be transmitted to the linear slit-shaped light transmitting hole group. 6, the light is efficiently condensed.
[0148]
In this case, as shown in FIG. 12, a solar cell panel with high power generation efficiency is formed by relatively moving the power generation structure 33 and the light condensing element 3 using a structure similar to that of FIG. Can be. The solar cell panel according to the second embodiment differs from the solar cell panel according to the first embodiment in that the substrate 1 on which the photoelectric conversion layer 2 is formed is fixed or moved. The characteristics were the same, and the same increase in power generation efficiency as in Table 1 shown in Example 1 was confirmed.
[0149]
Here, in the configuration shown in FIG. 12, it is necessary to take out the electric power generated from the power generation structure 33 which is a moving body. However, as can be seen from FIG. 5, the moving distance for one year is about ± 10 mm. By using a conductive metal plate having flexibility, stable electric power can be taken out. In the solar cell panel of Example 1 shown in FIG. 8, the substrate 1 having the photoelectric conversion layer 2 and the transparent first substrate 10 are independent, and each may have strength in order to prevent breakage. Was needed.
[0150]
However, as shown in FIGS. 11 and 12, the substrate 1 having the photoelectric conversion layer 2 and the first transparent substrate 10 are bonded and fixed in advance, and the power generation structure 33 is bonded and fixed by assembling a solar cell panel. The strength of the generated power generation structure 33 is increased. Therefore, even if the substrate 1 and the first transparent substrate 10 are thinned, the strength of the power generation structure 33 is increased, and the solar cell panel can be thinned.
[0151]
Next, as the first transparent substrate 10 of the second embodiment, similarly to the first embodiment, Y having a particle size of 5 μm was used. ₂ O ₂ S: A solar cell using the first transparent substrate containing 15% by volume of Eu, Mg, and Ti fluorescent particles was produced. As in the first embodiment, the power generation efficiency of the solar cell panel of the second embodiment using the first transparent substrate 10 having the fluorescent characteristic was examined. As a result, the first transparent substrate having the fluorescent characteristic was also obtained in the second embodiment. It was confirmed that the use of the substrate 10 increased the open-circuit voltage V by 5 to 8% and increased the short-circuit current I by 13 to 15% at all incident angles.
[0152]
Next, as the transparent adhesive 32 of Example 2, Y having a particle size of 5 μm was used. ₂ O ₂ S: A solar cell in which the light-collecting element 3 and the solar cell element were adhered and fixed using an ultraviolet curable resin containing 15% by volume of Eu, Mg, and Ti fluorescent particles was prepared. The thickness of the transparent adhesive layer was 0.2 mm. The fluorescent particles, which are introduced between the light reflection layer 5 and the photoelectric conversion layer 2, convert light having a wavelength of about 400 nm not used for photoelectric conversion into light having a wavelength of about 600 nm used for photoelectric conversion. Therefore, the light having a wavelength of about 600 nm generated from the fluorescent particles is further multiply reflected between the light reflection layer 5 and the photoelectric conversion layer 2, so that the power generation efficiency of the solar cell can be further increased.
[0153]
The power generation efficiency of the solar cell panel using the ultraviolet curable resin containing no fluorescent particles and the solar cell panel using the ultraviolet curable resin containing the fluorescent particles were examined in the same manner as in Example 1. As a result, in the solar cell panel using the ultraviolet curable resin containing the fluorescent particles, it was confirmed that the open-circuit voltage V was increased by 5 to 8% and the short-circuit current I was increased by 10 to 11% at all incident angles. .
[0154]
Here, comparing the case where the first transparent substrate 10 contains the fluorescent particles and the case where the transparent adhesive 32 contains the fluorescent particles, when the first transparent substrate 10 contains the fluorescent particles, It can be seen that a larger short-circuit current has been obtained. This result is due to the fact that the thickness of the transparent adhesive 32 is as thin as 0.2 mm while the plate thickness of the first transparent substrate 10 is 10 mm, and the amount of the fluorescent particles contained is different. I have.
[0155]
However, in any case, a larger short-circuit current can be obtained by increasing the content of the fluorescent particles. Further, by including fluorescent particles in both the first transparent substrate 10 and the transparent adhesive 32, it is possible to obtain a larger short-circuit current.
[0156]
In the solar cells described in Example 1 and Example 2, an electrode metal layer 11, a polycrystalline Si semiconductor layer 12, a polycrystalline Si semiconductor layer 13, a polycrystalline Si semiconductor layer 14, a comb were formed on a stainless steel substrate 1. Although a polycrystalline Si solar cell having the type current collecting electrode 15 and the conductive transparent film 16 is used, the present invention is not limited to this. It is also possible to use an amorphous Si semiconductor layer as the photoelectric conversion layer 2. In order to further increase the power generation efficiency, a pn junction made of a polycrystalline Si semiconductor and a pin junction made of an amorphous Si semiconductor are used. It is also possible to use a tandem-structure solar cell element in which is laminated.
[0157]
In addition, a single crystal Si solar cell, CuInSe ₂ , Cu (In, Ga) (S, Se) ₂ , CuGaSe ₂ It is also possible to use a photoelectric conversion layer used in CIS-based solar cells and the like.
[0158]
Further, in the solar cells described in Example 1 and Example 2, the light-collecting element 3 made of polycarbonate manufactured by the injection molding method was used as the light-collecting element 3, but the present invention is not limited to this. As other resin materials, it is possible to use a styrene-based transparent resin, an olefin-based transparent resin, an ethylene-based transparent resin, an acrylic-based transparent resin, and the like, and the manufacturing method is not limited to the injection molding method. It is possible to use a method or a hot forming method. Furthermore, it is also possible to use a glass condensing element 3 manufactured by a molding method or a roll forming method. By making the light-collecting element made of glass, environmental resistance is remarkably improved, and high power generation efficiency can be stably maintained even for long-term use.
[0159]
In the solar cells described in Example 1 and Example 2, as the fluorescent particles, Y having a particle size of 5 μm was used. ₂ O ₂ S: Fluorescent particles of Eu, Mg, Ti were used, but the present invention is not limited to this.
[0160]
For example, as fluorescent particles, Y having a particle size of 2 to 20 μm is used. ₂ O ₂ By using fluorescent particles of S: Eu, Mg, Ti, it is possible to absorb light having a wavelength of 200 to 450 nm and emit light having a wavelength of 625 nm. Also, Er ³⁺ By using the oxyfluoride-based crystallized glass containing ions, light having a wavelength of about 800 nm can be absorbed and light having a wavelength of 550 to 660 nm can be emitted.
[0161]
Other fluorescent materials include SrAl in which rare earth elements europium (Eu) and dysprosium (Dy) are added to a compound composed of strontium oxide and aluminum oxide. ₂ O ₄ : Eu, Dy and Sr ₄ Al ₁₄ O ₂₅ : Eu, Dy, CaAl ₂ O ₄ : Eu, Dy, and a fluorescent material such as ZnS: Cu can also be used.
[0162]
In addition, by including an organic dye such as a cyanine dye, a pyridine dye, and a rhodamine dye, it is also possible to convert short-wavelength light into long-wavelength light, thereby increasing power generation efficiency. It is possible.
[0163]
Furthermore, higher power generation efficiency can be obtained by using a plurality of these fluorescent materials simultaneously in an arbitrary combination.
[0164]
Further, in the solar cells of Example 1 and Example 2, sunlight is condensed by the group of cylindrical condensing curved surfaces 4 onto the group of linear slit-shaped light transmitting holes 6 and passes through the first transparent substrate 10. Thus, the configuration is such that incident light is multiple-reflected between the photoelectric conversion layer 2 and the reflection layer 5, but the first transparent substrate 10 having the linear slit-shaped light transmission hole group 6 is turned upside down, After being condensed by the cylindrical converging curved surface group 4 and passing through the first transparent substrate 10, the light passes through the linear slit-shaped light transmitting hole group 6 and enters between the photoelectric conversion layer 2 and the light reflection layer 5. A configuration in which light is reflected multiple times is also possible. However, in this case, since the first transparent substrate 10 exists outside the multiple reflection system, the effect of improving the power generation efficiency cannot be obtained even if a transparent substrate having fluorescent characteristics is used.
[0165]
[Example 3]
As Example 3 of the present invention, a solar cell having the configuration shown in FIG. 13 was manufactured.
[0166]
The solar cell according to the third embodiment includes a condensing element 3 having the cylindrical condensing curved surface group 4 described in the first embodiment and a linear slit-shaped light transmitting hole group 6 on both surfaces of the solar cell element transparent substrate 34. And a power generation structure on which the photoelectric conversion layer 35 is formed. In this case, the light incident from the cylindrical condensing curved surface group 4 is condensed on the linear slit-shaped light transmitting hole group 6, transmitted through the solar cell element transparent substrate 34, incident on the photoelectric conversion layer 35, and The reflected light from the conversion layer 35 is reflected by the light reflection layer 5 and reenters the photoelectric conversion layer 35. Therefore, high power generation efficiency is realized by multiple reflection of incident light between the photoelectric conversion layer 35 and the light reflection layer 5.
[0167]
The photoelectric conversion layer 35 of Example 3 has the configuration shown in FIG. 14 and was manufactured as follows.
[0168]
A 30-nm thick SnO film is formed on a transparent glass substrate 34 for a solar cell element having a thickness of 5 mm. ₂ After the transparent conductive layer 36 is formed by reactive sputtering, a shielding mask is mounted on the surface of the transparent conductive layer 36 formed on the substrate 34, and sputtering is performed using an AlTi alloy target to form an Al film having a thickness of 100 nm. _0.95 Ti _0.05 A comb-shaped current collecting electrode 37 made of an alloy and having a width of 0.1 mm and an interval of 5 mm was formed.
[0169]
Next, a photoelectric conversion layer made of an amorphous Si semiconductor in which a p-layer 38 as a p-type impurity-doped semiconductor layer, an i-layer 39 as an intrinsic semiconductor, and an n-layer 40 as an n-type impurity-doped layer are stacked in this order. It was formed by a vapor phase growth method using a plasma CVD apparatus. Each semiconductor layer is made of SiH ₄ Gas H ₂ Gas / CH ₄ Gas B ₂ H ₆ A-SiC: H p-layer 38 having a thickness of 15 nm grown by vapor phase using a gas mixture of SiH ₄ Gas H ₂ A-Si: H i-layer 39 having a thickness of 100 nm grown by vapor phase using a gas mixture of SiH, ₄ Gas H ₂ Gas / PH ₃ An n-layer 40 of a-Si: H having a film thickness of 15 nm was formed by vapor phase growth using a mixed gas of gases.
[0170]
After the formation of the photoelectric conversion layer 35, an electrode metal layer 41 having a light reflection effect of Al having a thickness of 100 nm is formed by sputtering, and an ultraviolet curable resin is applied on the electrode metal layer 41. A protective film was used. Next, after a shielding mask corresponding to the linear slit-shaped light transmitting hole group 6 was attached to the surface of the transparent glass substrate for a solar cell element 34 where the photoelectric conversion layer 35 was not provided, an AlTi alloy target was used. 100 nm thick Al by sputtering _0.95 Ti _0.05 The light reflecting layer 5 made of an alloy was formed to obtain a power generation structure shown in FIG.
[0171]
A solar cell panel having the same configuration as that of FIG. In addition, the solar cell panel of Comparative Example 3 including only the transparent glass substrate for a solar cell element 34 and the photoelectric conversion layer 35 of Example 3 was used. The solar cell panels of Example 3 and Comparative Example 3 were measured at 100 mW / cm using a solar simulator in the same manner as in Example 1. ² The open-circuit voltage V and the short-circuit current I of both were measured.
[0172]
[Table 2]

[0173]
Table 2 shows that the open-circuit voltage V and the short-circuit current of the solar cell panel when the incident angle R is −23.4 °, −20 °, −10 °, 0 °, 10 °, 20 °, and 23.4 °. The solar cell element was moved so that I became maximum, and the open-circuit voltage V and the short-circuit current I of the solar cell panel of Example 3 were determined, and the open-circuit voltage V and the short-circuit current I of Comparative Example 3 were determined as 100%. It is a thing.
[0174]
In Example 3a, the open-circuit voltage V and the short-circuit current I when the interval between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is 28 mm, which is the same as the focal length F of the cylindrical converging curved surface group. In Example 3b, the open-circuit voltage V and the short-circuit current I when the interval between the cylindrical condensing curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is 22 mm, which is 6 mm smaller than the focal length F, are shown. Is shown.
[0175]
In both Example 3a and Example 3b, the open-circuit voltage V and the short-circuit current I are larger than 100%. This is because sunlight condensed by the cylindrical condensing curved surface group 4 passes through the linear slit-shaped light transmitting hole group 6, and multiple reflection between the photoelectric conversion layer 35 and the light reflecting layer 5 is realized. This indicates that the power generation efficiency is high.
[0176]
Further, as in the case of the first embodiment, in the third embodiment, despite the occurrence of the coma due to the increase of the incident angle R, the efficient light-collecting characteristic to the linear slit-shaped light transmitting hole group 6 is improved. It can be seen that even when the incident angle R is ± 23.4 °, the same open-circuit voltage and short-circuit current are obtained as when the incident angle R is 0 °.
[0177]
That is, also in the third embodiment, similarly to the first embodiment, the interval between the cylindrical converging curved surface group 4 and the linear slit-shaped light transmitting hole group 6 is made smaller than the focal length F of the cylindrical converging curved surface group 4. Thus, it can be seen that more efficient light-collecting characteristics to the linear slit-shaped light transmitting hole group 6 are realized, and high power generation efficiency independent of the incident angle R can be obtained.
[0178]
Here, when comparing Example 1 (Table 1) and Example 3 (Table 2), in the case of Example 1, the short-circuit current I increased to 145%, whereas in the case of Example 3, It can be seen that the short-circuit current I has increased only up to about 130%.
[0179]
This is because, in Example 3, the photoelectric conversion layer 35 and the light reflection layer 5 having the linear slit-shaped light transmitting hole group 6 were provided on both surfaces of the transparent substrate for a solar cell element, and thus the transparent for the solar cell element was provided. When the photoelectric conversion layer 35 is formed on one surface of the substrate 34, scattering and reflection of incident light may occur due to generation of scratches or dust on the other surface of the transparent substrate 34 for a solar cell element on which the light reflection layer 5 is to be formed. This is because the reflectance of the light reflecting layer 5 has been reduced.
[0180]
Therefore, in order to realize higher power generation efficiency, the configuration of Example 1 in which the photoelectric conversion layer 2 and the light reflection layer 5 are formed on separate substrates, or the method of separately forming and then integrating with an adhesive. The configuration of Example 2 is desirable. However, according to the configuration of the third embodiment, the number of substrates can be reduced, and the cost and thickness of the solar cell panel can be reduced.
[0181]
In the third embodiment, the case where the light reflecting layer 5 is formed after the formation of the photoelectric conversion layer 35 on the transparent glass substrate 34 for a solar cell element has been described. The conversion layer 35 can also be formed. However, when the photoelectric conversion layer 35 is formed after the formation of the light reflection layer 5, the photoelectric conversion layer 35 itself is formed due to scratches or dust attached to the surface on which the photoelectric conversion layer 35 is formed when the light reflection layer 5 is formed. Characteristics may be deteriorated, which may lead to an extreme decrease in power generation efficiency. Therefore, as described in the third embodiment, it is desirable to form the light reflection layer 5 after forming the photoelectric conversion layer 35.
[0182]
Next, as the transparent substrate 34 for a solar cell element, Y having a particle size of 5 μm was used. ₂ O ₂ S: A solar cell using a glass substrate containing 15% by volume of Eu, Mg, and Ti fluorescent particles was produced. The fluorescent particles can convert light having a wavelength of about 400 nm not used for photoelectric conversion into light having a wavelength of about 600 nm used for photoelectric conversion. The multiple reflection between the light-collecting element 3 and the solar cell element makes it possible to further increase the power generation efficiency of the solar cell.
[0183]
The solar cell of Example 3 using the transparent substrate for solar cell element 34 containing no fluorescent particles and the solar cell of Example 3 using the transparent substrate 34 for solar cell element containing fluorescent particles were exposed to sunlight. 100mW / cm using a simulator ² The open-circuit voltage V and the short-circuit current I of both were measured by changing the incident angle of the light, and as a result, the open substrate was opened at all the incident angles by using the solar cell element transparent substrate 34 containing the fluorescent particles. It was confirmed that the voltage V increased by 6 to 9% and the short-circuit current I increased by 13 to 15%.
[0184]
In the third embodiment, as a semiconductor for performing photoelectric conversion, a p-layer 38 as a p-type impurity-doped semiconductor layer, an i-layer 39 as an intrinsic semiconductor, and an n-layer 40 as an n-type impurity-doped layer are laminated in this order. Although the embodiment using the amorphous Si semiconductor described above is described, it is also possible to use the polycrystalline Si semiconductor described in Embodiments 1 and 2.
[0185]
However, when a polycrystalline Si semiconductor is used, it is desirable to change the order of formation. That is, a polycrystalline Si semiconductor layer doped with p-type impurities at a high concentration, a polycrystalline Si semiconductor layer doped slightly with n-type impurities, It is desirable to form a structure in which a polycrystalline Si semiconductor layer doped with a high-type impurity at a high concentration is sequentially formed.
[0186]
Similarly, in the first and second embodiments, the amorphous Si semiconductor described in the third embodiment can be used.
[0187]
[Example 4]
The solar cell of Example 3 has a configuration in which the photoelectric conversion layer 35 and the light reflection layer 5 are provided on both surfaces of the transparent substrate for a solar cell element 34, respectively. As shown, only the photoelectric conversion layer 35 is provided on the solar cell element transparent substrate 34, and the first transparent substrate 10 similar to the first embodiment is replaced with the light-collecting element 3 and the solar cell element transparent substrate 34. It is a configuration provided movably between them.
[0188]
In the third embodiment, the photoelectric conversion layer 35 and the light reflection layer 5 having the linear slit-shaped light transmission hole group 6 are provided on both surfaces of the transparent substrate for a solar cell element. When the photoelectric conversion layer 35 is formed on one surface of the transparent cell 34, scattering and reflection of incident light and light due to scratches and dust adhesion on the other surface of the solar cell element transparent substrate 34 on which the light reflecting layer 5 is to be formed. There was a problem that the power generation efficiency was reduced due to the decrease in the reflectance of the reflective layer 5, but as shown in Example 4, the photoelectric conversion layer 35 and the light reflective layer 5 were formed on separate substrates. By forming, the above-mentioned problem was solved, and an increase in the short-circuit current I of the same level as in the first embodiment (145%) was realized.
[0189]
In this case, the incident light 7 is condensed on the linear slit-shaped light transmitting hole group 6 by the cylindrical converging curved surface group 4 and passes through the first transparent substrate 10 and the transparent substrate 34 for a solar cell element. The incident light is multiply reflected between the conversion layer 35 and the light reflection layer 5. Therefore, by using a transparent substrate having the same fluorescence characteristics as in the first embodiment as the first transparent substrate 10 or the transparent substrate for a solar cell element 34, it is possible to further increase the power generation efficiency.
[0190]
In Example 1, power generation efficiency could be increased by using only the first transparent substrate 10 existing between the photoelectric conversion layer 2 and the light reflection layer 5 as a transparent substrate having a fluorescent property. On the other hand, in the present embodiment, the first transparent substrate 10 and the transparent substrate for solar cell 34 exist between the photoelectric conversion layer 35 and the light reflection layer 5, and as both substrates, It is possible to use a transparent substrate having fluorescent properties. Therefore, it is possible to generate light having a wavelength contributing to photoelectric conversion as fluorescence in both the first transparent substrate 10 and the transparent substrate for a solar cell 34 as fluorescence, and to further increase the power generation efficiency as compared with the first embodiment. Becomes possible.
[0191]
Further, in the configuration shown in FIG. 15, the first transparent substrate 10 having the linear slit-shaped light transmitting hole group 6 is turned upside down, and sunlight is condensed by the cylindrical condensing curved surface group 4, and the first transparent substrate 10 , After passing through the group of straight slit-shaped light transmitting holes 6, passing through the transparent substrate for solar cell element 34, and multiple reflection of incident light between the photoelectric conversion layer 35 and the light reflecting layer 5. It is also possible. In this case, since the first transparent substrate 10 exists outside the multiple reflection system, even if a transparent substrate having a fluorescent property is used as the first transparent substrate 10, the power generation efficiency cannot be improved. However, by using a transparent substrate having fluorescent characteristics as the solar cell element transparent substrate 34, the power generation efficiency is improved.
[0192]
Next, as shown in FIG. 16, the transparent substrate for a solar cell element having the photoelectric conversion layer 35 and the first transparent substrate 10 having the light reflection layer 5 are bonded to each other with a transparent adhesive 42, 1 By moving the transparent substrate 10 and the transparent substrate 34 for a solar cell element having the photoelectric conversion layer 35 integrally, the cylindrical condensing curved surface group 4 and the linear slit-shaped light transmitting hole group 6 are relatively moved. It is also possible to make it.
[0193]
In this case, the first transparent substrate 10 and the solar cell element transparent substrate 34 having the photoelectric conversion layer 35 are bonded and fixed, whereby the mechanical strength is increased, and as compared with the solar cell panel shown in FIG. The substrate thickness of the first transparent substrate 10 and the solar cell element transparent substrate 34 can be reduced, and the solar cell panel can be reduced in thickness.
[0194]
In addition, by using a transparent substrate having the same fluorescence characteristics as in the first embodiment as the first transparent substrate 10 or the transparent substrate for a solar cell element 34, it is possible to increase the power generation efficiency.
[0195]
Further, as in the case of FIG. 15, by using a transparent substrate having a fluorescent property as both the first transparent substrate 10 and the transparent substrate for a solar cell element 34, the first transparent substrate 10 and the solar cell Light having a wavelength contributing to photoelectric conversion can be generated as fluorescence in both of the transparent substrate 34 and the power generation efficiency can be further increased.
[0196]
Further, similarly to the second embodiment, the power generation efficiency can be increased also by using the transparent adhesive 42 having fluorescent characteristics by including the fluorescent particles in the transparent adhesive 42. Furthermore, by using a transparent substrate having a fluorescent property and using a transparent adhesive 42 having a fluorescent property as both the first transparent substrate 10 and the transparent substrate for a solar cell element 34, the cost is higher. It is possible to obtain power generation efficiency.
[0197]
As shown in FIGS. 1, 11, 15, and 16, the solar cell according to the present invention includes a light-collecting element provided with the light-condensing curved surface group and a solar cell element having the photoelectric conversion layer. In addition, a first transparent substrate is provided so as to be movable, and the light reflection layer having the light transmission hole group is provided on the first transparent substrate.
[0198]
With the above configuration, the light-collecting element, the first transparent substrate, and the solar cell element can be formed independently of each other, and damages such as scratches generated in a manufacturing process are suppressed, and high A solar cell having power generation efficiency can be stably manufactured.
[0199]
Further, the solar cell according to the present invention is characterized in that, in addition to the above configuration, the first transparent substrate and the solar cell element are fixed by a transparent adhesive.
[0200]
With the above configuration, in addition to the above effects, the first transparent substrate and the solar cell element are bonded and fixed in advance, so that the mechanical strength of the first transparent substrate and the solar cell element is reduced. As a result, in the manufacturing process, it is possible to suppress a decrease in yield due to breakage or the like, and to realize a thin solar cell.
[0201]
Further, in the solar cell according to the present invention, as shown in FIG. 13, the photoelectric conversion layer is provided on one surface of a transparent substrate for a solar cell element, and the photoelectric conversion layer of the transparent substrate for a solar cell element is provided. The light reflection layer having the light transmission hole group is provided on a surface facing the light reflection layer.
[0202]
With the above configuration, it is possible to form both the photoelectric conversion layer and the light reflection layer on the transparent substrate for a solar cell element, and to manufacture a solar cell with the minimum required number of substrates. It is possible, and the cost of the solar cell can be reduced, and the thickness of the solar cell can be reduced.
[0203]
In addition, in the solar cell according to the present invention, as shown in FIGS. 15 and 16, a first transparent substrate is provided between the light-collecting element and the solar cell element, and the first transparent substrate The light reflection layer having the light transmission hole group is provided, and the photoelectric conversion layer is provided on a transparent substrate for a solar cell element.
[0204]
With the above configuration, the light-collecting element, the first transparent substrate, and the solar cell element can be formed independently of each other, and damages such as scratches generated in a manufacturing process are suppressed, and high A solar cell having power generation efficiency can be stably manufactured.
[0205]
Further, the solar cell according to the present invention is characterized in that, in addition to the above configuration, the first transparent substrate and the solar cell element are fixed by a transparent adhesive.
[0206]
With the above configuration, in addition to the above effects, the first transparent substrate and the solar cell element are bonded and fixed in advance, so that the mechanical strength of the first transparent substrate and the solar cell element is reduced. It is possible to suppress a decrease in yield due to breakage or the like in the manufacturing process.
[0207]
Further, the solar cell according to the present invention is characterized in that a transparent substrate having a fluorescent property is provided between the light reflection layer and the photoelectric conversion layer.
[0208]
With the above configuration, the amount of light having a wavelength that contributes to photoelectric conversion increases, so that the power generation efficiency of the solar cell can be further increased.
[0209]
Further, a solar cell according to the present invention is characterized in that a transparent adhesive layer having a fluorescent property is included in a laminated structure between the light reflection layer and the photoelectric conversion layer.
[0210]
In the above configuration, various modes of a laminated structure in which a transparent adhesive layer is interposed between the light reflecting layer and the photoelectric conversion layer can be included. For example, a light-collecting element having a light-reflecting layer formed on the surface of the light-collecting element on the solar cell element side may be bonded and fixed to the solar cell element via a transparent adhesive layer. Alternatively, a transparent substrate that controls the distance between the light-collecting element and the solar cell element may be bonded and fixed between the light-collecting element and the solar cell element via a transparent adhesive layer. Alternatively, a transparent substrate having a light reflecting layer formed on the surface on the light-collecting element side may be bonded and fixed to the solar cell element via a transparent adhesive layer.
[0211]
As described above, the power generation efficiency of the solar cell can be further increased by interposing the transparent adhesive layer having the fluorescent property in the laminated structure that can take various aspects.
[0212]
The present invention is not limited to the above-described embodiments and examples, and various modifications are possible within the scope of the claims, and the technical means disclosed in the different embodiments and examples may be appropriately changed. Embodiments and examples obtained in combination are also included in the technical scope of the present invention.
[0213]
【The invention's effect】
According to the present invention, light incident from the light condensing region is condensed into the light transmission hole, enters the solar cell element having the photoelectric conversion layer, and reflected light from the solar cell element is reflected by the light reflecting layer. Then, the light is again incident on the solar cell element. Therefore, the power generation efficiency of the solar cell can be increased by multiple reflection of the incident light between the light reflection layer and the solar cell element.
[0214]
Furthermore, the light-collecting area and the light-transmitting hole are supported so as to be relatively movable, so that the sunlight collected by the light-collecting area always collects in the light-transmitting hole according to the incident angle of sunlight. By controlling the position of the light-gathering area and the light-transmitting holes so that light is emitted, high conversion efficiency can be maintained even when the sunlight incident angle changes due to the inclination of the earth axis. It is possible to realize a simple solar cell.
[0215]
Further, in the present invention, by using a transparent substrate and a transparent adhesive having fluorescence properties as the transparent substrate and the transparent adhesive, light having a wavelength that cannot be used for photoelectric conversion in the photoelectric conversion layer has a wavelength that can be used for photoelectric conversion. Since it can be converted into light, it is possible to further increase the power generation efficiency of the solar cell.
[Brief description of the drawings]
FIG. 1 is a schematic sectional perspective view of a solar cell of the present invention.
FIG. 2 is a schematic cross-sectional perspective view showing a relationship between a light condensing position of light incident obliquely from above in the horizontal direction and a position of a light transmitting hole group in the solar cell of the present invention.
FIG. 3 is a view illustrating a method for installing a solar cell according to the present invention.
FIG. 4 is a schematic cross-sectional perspective view showing the relationship between the light condensing position of light incident obliquely from above in the vertical direction and the position of the light transmitting hole group in the solar cell of the present invention.
FIGS. 5A to 5C are explanatory diagrams showing the results of calculation of the light-collecting state of the solar cell of the present invention by changing the incident angle.
FIGS. 6 (a) to 6 (c) are explanatory views showing calculation results of a light condensing state in a case where a group of light transmitting holes is brought close to a group of condensing curved surfaces in a solar cell of the present invention, by changing an incident angle. FIG.
FIG. 7 is a schematic sectional view of a solar cell element of the present invention.
FIG. 8 is a sectional view of a main part of the solar cell panel of the present invention.
FIG. 9 is a schematic plan view of a solar cell panel of the present invention.
FIG. 10 is a block diagram showing a configuration of a control system for controlling a relative position between the light-collecting element and the light transmitting hole group in the solar cell panel of the present invention.
FIG. 11 is a schematic sectional perspective view showing another configuration of the solar cell of the present invention.
FIG. 12 is a schematic sectional view showing another configuration of the solar cell panel of the present invention.
FIG. 13 is a schematic cross-sectional perspective view showing still another configuration of the solar cell of the present invention.
FIG. 14 is a schematic sectional view showing another configuration of the solar cell element of the present invention.
FIG. 15 is a schematic sectional perspective view showing still another configuration of the solar cell of the present invention.
FIG. 16 is a schematic sectional perspective view showing still another configuration of the solar cell of the present invention.
FIG. 17 is a schematic sectional view showing an example of a conventional solar cell.
FIG. 18 is a schematic sectional view showing another example of a conventional solar cell.
FIG. 19 is a schematic sectional view showing still another example of a conventional solar cell.
FIG. 20 is a schematic cross-sectional perspective view of a solar cell according to the present invention.
FIGS. 21 (a) and (b) are explanatory diagrams showing the results of calculating the light-collecting state of a solar cell related to the present invention by changing the incident angle.
[Explanation of symbols]
1 substrate (solar cell element)
2 Photoelectric conversion layer (solar cell element)
3 Condensing element
4 Cylindrical condensing curved surfaces (collection of condensing areas)
5 Light reflection layer
6 straight slit light transmission holes
7 Incident light
8 vertical direction
9 horizontal direction
10 1st transparent substrate
32 transparent adhesive
33 Power Generation Structure
34 Transparent substrate for solar cell element
35 photoelectric conversion layer
42 transparent adhesive
F focal length
Q Incident angle
R Incident angle

Claims (9)

A solar cell element having a photoelectric conversion layer,
A light-collecting element having a light-collecting region;
A light reflection layer having a light transmission hole,
The light reflecting layer is configured such that light collected by the light collecting region passes through the light transmitting hole and then enters the solar cell element, and reflected light from the solar cell element is reflected by the light reflecting layer. Formed between the solar cell element and the light-collecting element so as to re-enter the solar cell element;
The light-collecting element and the light-reflective layer are relatively movably supported so that the amount of light passing through the corresponding light-transmitting holes when the light collected by the light-collecting region can be adjusted. A solar cell characterized by being made. The solar cell according to claim 1,
The light-collecting region is a cylindrical light-collecting curved surface, the light-transmitting hole is a linear slit-shaped light-transmitting hole, and the direction of the cylindrical axis of the cylindrical light-collecting curved surface and the extension of the linear slit-shaped light-transmitting hole. A solar cell, wherein the direction is arranged in parallel. The solar cell according to claim 1 or claim 2,
A solar cell, comprising: a transparent substrate on which a light reflection layer having at least the light transmission hole is formed between the light-collecting element and the solar cell element, wherein the transparent substrate is movable. The solar cell according to claim 3,
The solar cell, wherein the light reflection layer is formed on a light incident side of the transparent substrate, and the transparent substrate emits fluorescence having a wavelength that contributes to photoelectric conversion of the photoelectric conversion layer. The solar cell according to claim 1 or claim 2,
Between the light-collecting element and the solar cell element, a transparent substrate provided with the light reflection layer having the light transmission holes is provided,
A solar cell, wherein the transparent substrate and the solar cell element are fixed with a transparent adhesive, and the transparent adhesive emits fluorescence having a wavelength that contributes to photoelectric conversion of the photoelectric conversion layer. The solar cell according to claim 2,
A solar cell, wherein a distance between the cylindrical converging curved surface and the light reflecting layer is shorter than a focal length of the cylindrical converging curved surface. The solar cell according to claim 2,
A solar cell, wherein a plane including the cylindrical axial direction of the cylindrical light-collecting curved surface and perpendicular to the light-collecting element is installed so as to face east-west. The solar cell according to claim 7,
A solar cell, wherein the light-collecting element having the cylindrical light-collecting curved surface and the reflection layer having the linear slit-shaped light transmitting hole are supported so as to be relatively movable in the north-south direction. The solar cell according to claim 8,
A solar cell, wherein the solar cell is installed such that the incident angle of sunlight with respect to the solar cell becomes 0 ° when the installation angle of the solar cell is in the middle of the spring equinox or the autumn equinox.

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