JP2004253143A

JP2004253143A - Electrochemical element and electrode used for it

Info

Publication number: JP2004253143A
Application number: JP2003023619A
Authority: JP
Inventors: Masaru Nishimura; 賢西村; Naoto Arai; 直人荒井; Toru Oshima; 透大島; Fumio Oo; 文夫大尾; Munehisa Ikoma; 宗久生駒; Hideo Kaiya; 英男海谷
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-12-27
Filing date: 2003-01-31
Publication date: 2004-09-09
Anticipated expiration: 2023-01-31
Also published as: JP4594591B2

Abstract

【課題】構造が簡略であり、高出力であり、信頼性が高く、高い電気容量を有する電気化学素子を効率的に製造する。
【解決手段】第１電極は、第１集電体シート１３ａおよびこれに担持された少なくとも１つの第１電極合剤層１４ａからなり、第２電極は、第２集電体シート１３ｂおよびこれに担持された少なくとも１つの第２電極合剤層１４ｂからなり、第１集電体シートの少なくとも１つの端部が、第１電極合剤層の未塗工部であり、第２集電体シートの少なくとも１つの端部が、第２電極合剤層の未塗工部であり、第１集電体シートの未塗工部が、極板群の第１側面において、第１端子１７ａと接続され、第２集電体シートの未塗工部が、極板群の第２側面において、第２端子１７ｂと接続され、第１集電体シートの未塗工部の少なくとも一部が、第１端子に埋没しており、第２集電体シートの未塗工部の少なくとも一部が、第２端子に埋没している電気化学素子。
【選択図】図１An electrochemical device having a simple structure, high output, high reliability, and high electric capacity is efficiently manufactured.
A first electrode includes a first current collector sheet and at least one first electrode mixture layer supported on the first current collector sheet, and a second electrode includes a second current collector sheet and a second current collector sheet. The first current collector sheet is formed of at least one second electrode mixture layer 14b, and at least one end of the first current collector sheet is an uncoated portion of the first electrode mixture layer. Is an uncoated portion of the second electrode mixture layer, and the uncoated portion of the first current collector sheet is connected to the first terminal 17a on the first side surface of the electrode plate group. The uncoated portion of the second current collector sheet is connected to the second terminal 17b on the second side surface of the electrode plate group, and at least a part of the uncoated portion of the first current collector sheet is It is buried in one terminal, and at least a part of the uncoated portion of the second current collector sheet is buried in the second terminal Gas-chemical element.
[Selection diagram] Fig. 1

Description

【０００１】
【発明の属する技術分野】
本発明は、電気化学素子に関し、特にリチウムイオン二次電池などの高エネルギー密度を有する二次電池に用いる極板群の集電構造の改良に関する。
【０００２】
【従来の技術】
電子・電気機器の小型化・軽量化に伴い、二次電池などの電気化学素子に対する小型化・軽量化への要望が強まってきている。一方、現行の二次電池は、内部構造が複雑であり、一定容積あたりの製品が有する電気容量を向上させるには限界がある。複雑な構造が、電池の信頼性の向上を妨げている面もある。例えば、電極に接続された集電タブまたは集電リードが、電極面における均一な電極反応を妨げる場合がある。万一、リードの切断面に通常よりも大きな金属バリが生じた場合には、内部短絡の発生も懸念される。
【０００３】
二次電池は、正極、負極およびセパレータからなる極板群を有し、極板群には、積層型と捲回型がある。積層型の極板群は、正極と負極とをセパレータを介して交互に積層して得られる。捲回型の極板群は、長尺の正極と負極とをセパレータを介して捲回して得られる。これらの極板群は、通常、正極と負極の端部が面一に配列した側面を有する。このような側面から短絡を起こさずに電気を取り出すには、集電タブや集電リードが必要となる。
【０００４】
高出力が要求される電池においては、極板群の側面の１つから正極を突出させ、前記側面とは逆側の側面から負極を突出させ、集電タブや集電リードを介さずに、各側面から直接電気を取り出すことが提案されている。例えば、積層型の極板群を有する電池では、突出させた同一極性の極板を、所定の金属部材を用いて一体接合する技術が提案されている（例えば、特許文献１参照）。捲回型の極板群を有する電池では、突出させた同一極性の極板の芯材と板状の集電板とを接合する技術が提案されている（例えば、特許文献２参照）。
【０００５】
【特許文献１】
特開２００１−１２６７０７号公報
【特許文献２】
特開２０００−２９４２２２号公報
【０００６】
【発明が解決しようとする課題】
しかし、集電タブや集電リードが極板群の内部に配置されると、極板群の構造が不均等かつ複雑になるため、体積効率が低下して、極板群のエネルギー密度が低下したり、電極反応が不均一になって、電気化学素子の信頼性が低下したりする。集電タブや集電リードが有する金属バリにより、内部短絡が起こる可能性もある。
【０００７】
極板群の側面の１つから正極を突出させ、前記側面とは逆の側面から負極を突出させ、突出させた同一極性の極板を、所定の金属部材を用いて一体接合する方法では、製造工程が複雑であり、しかも、極板の突出部の導電性が低いために、集電性能が低くなるという問題がある。例えば、導電性の低い電極合剤層と金属部材との接触によっては、充分な集電が行えないし、金属部材と端面が接触する電極芯材が薄い場合には、集電性能はさらに低下する。突出させた同一極性の極板の芯材と板状の集電板とを接合する場合には、芯材と集電板との接触面積を確保することが困難であり、高出力を達成できないという問題がある。
【０００８】
【課題を解決するための手段】
本発明は、上記状況を鑑みてなされたものである。本発明によれば、高出力であり、構造が簡略であり、信頼性が高く、高い電気容量を有する電気化学素子を提供することができる。また、本発明によれば、同時に複数の電気化学素子を効率的に製造することができる。
【０００９】
すなわち、本発明は、（ａ）少なくとも１つの第１電極、（ｂ）少なくとも１つの第２電極、および（ｃ）第１電極と第２電極との間に介在するセパレータからなる極板群を有する電気化学素子であって、前記第１電極（ａ）は、第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記第２電極（ｂ）は、第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記第１集電体シートの少なくとも１つの端部が、前記第１電極合剤層の未塗工部であり、前記第２集電体シートの少なくとも１つの端部が、前記第２電極合剤層の未塗工部であり、前記第１集電体シートの未塗工部が、前記極板群の第１側面において、第１端子と接続され、前記第２集電体シートの未塗工部が、前記極板群の第２側面において、第２端子と接続され、前記第１集電体シートの未塗工部の少なくとも一部が、前記第１端子に埋没しており、前記第２集電体シートの未塗工部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子Ｘという）に関する。
【００１０】
本発明は、また、複数の第１電極と複数の第２電極とをセパレータを介して交互に積層した極板群を有する電気化学素子であって、前記複数の第１電極は、それぞれ第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記複数の第２電極は、それぞれ第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各第１集電体シートの少なくとも１つの端部が、前記第１電極合剤層の未塗工部であり、前記各第２集電体シートの少なくとも１つの端部が、前記第２電極合剤層の未塗工部であり、前記各第１集電体シートの未塗工部が、前記極板群の第１側面において、第１端子と接続され、前記各第２集電体シートの未塗工部が、前記極板群の第２側面において、第２端子と接続され、前記第１集電体シートの未塗工部の少なくとも一部が、前記第１端子に埋没しており、前記第２集電体シートの未塗工部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子Ｙという）に関する。
【００１１】
本発明は、また、（ａ）少なくとも１つの第１電極、（ｂ）少なくとも１つの第２電極、および（ｃ）第１電極と第２電極との間に介在するセパレータからなる極板群を有する電気化学素子であって、前記第１電極（ａ）は、導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記第２電極（ｂ）は、導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部は、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１側面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２側面において第２端子と接続され、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子Ｚという）に関する。
【００１２】
本発明は、また、複数の第１電極と複数の第２電極とをセパレータを介して交互に積層した極板群を有する電気化学素子であって、前記複数の第１電極は、それぞれ導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記複数の第２電極は、それぞれ導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部は、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１側面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２側面において第２端子と接続され、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子Ｗという）に関する。
【００１３】
電気化学素子Ｘ、Ｙ、ＺおよびＷにおいては、前記第１側面と前記第２側面とを、互いに前記極板群の反対側に位置させることができる。
電気化学素子Ｘ、Ｙ、ＺおよびＷにおいては、前記第１側面に、前記第１端子と前記第２電極とを絶縁するための第１絶縁材料部を設け、前記第２側面に、前記第２端子と前記第１電極とを絶縁するための第２絶縁材料部を設けることができる。
電気化学素子Ｙ、Ｗにおいては、前記第１側面および前記第２側面以外の前記極板群の側面に、絶縁材料を配することができる。
【００１４】
電気化学素子ＺおよびＷにおいては、前記露出している第１集電体シートの絶縁部を、前記第２側面に配し、前記露出している第２集電体シートの絶縁部を、前記第１側面に配することができる。
電気化学素子ＺおよびＷにおいては、前記各集電体シートの第１端部および第２端部を含む周縁部を、前記電極合剤層の未塗工部とし、前記第１端子または第２端子との接続位置以外の周縁部は絶縁部とすることができる。
電気化学素子ＺおよびＷにおいては、前記第１側面および前記第２側面以外の前記極板群の側面に、前記第１集電体シートの絶縁部の露出部および前記第２集電体シートの絶縁部の露出部を配することができる。
電気化学素子ＺおよびＷにおいては、前記極板群が、前記第１側面および前記第２側面以外に、前記第１集電体シートの絶縁部の露出部および／または前記第２集電体シートの絶縁部の露出部が配されている側面を有することができる。
【００１５】
本発明は、また、導電部と絶縁部とを有する集電体シートおよびこれに担持された少なくとも１つの電極合剤層からなり、前記集電体シートの第１端部および第２端部は、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出している電気化学素子用電極に関する。前記電極においては、前記第１端部および前記第２端部を、互いに前記集電体シートの反対側に位置させることができる。
【００１６】
本発明には、例えば、以下の電気化学素子が含まれる。
第１電極と第２電極とをセパレータを介して捲回した極板群を有する電気化学素子であって、前記第１電極は、導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記第２電極は、導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部は、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１底面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２底面において第２端子と接続され、前記露出している第１集電体シートの絶縁部が、前記第２底面に配され、前記露出している第２集電体シートの絶縁部が、前記第１底面に配されており、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子ａという）。
【００１７】
第１電極と第２電極とをセパレータを介して捲回した極板群を有する電気化学素子であって、前記第１電極は、導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記第２電極は、導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部は、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１底面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２底面において第２端子と接続され、前記露出している第１集電体シートの絶縁部が、前記第２底面に配され、前記露出している第２集電体シートの絶縁部が、前記第１底面に配され、前記第１底面には、前記第１端子と前記第２電極とを絶縁するための第１絶縁材料部が設けられており、前記第２底面には、前記第２端子と前記第１電極とを絶縁するための第２絶縁材料部が設けられており、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子ｂという）。
【００１８】
複数の第１電極と複数の第２電極とをセパレータを介して交互に積層した極板群を有する電気化学素子であって、前記複数の第１電極は、それぞれ導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記複数の第２電極は、それぞれ導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部は、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１側面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２側面において第２端子と接続され、前記露出している第１集電体シートの絶縁部が、前記第２側面に配され、前記露出している第２集電体シートの絶縁部が、前記第１側面に配され、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子ｃという）。
【００１９】
複数の第１電極と複数の第２電極とをセパレータを介して交互に積層した極板群を有する電気化学素子であって、前記複数の第１電極は、それぞれ導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記複数の第２電極は、それぞれ導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部は、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１側面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２側面において第２端子と接続され、前記露出している第１集電体シートの絶縁部が、前記第２側面に配され、前記露出している第２集電体シートの絶縁部が、前記第１側面に配され、前記第１側面には、前記第１端子と前記第２電極とを絶縁するための第１絶縁材料部が設けられており、前記第２側面には、前記第２端子と前記第１電極とを絶縁するための第２絶縁材料部が設けられており、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子ｄという）。
【００２０】
複数の第１電極と複数の第２電極とをセパレータを介して交互に積層した極板群を有する電気化学素子であって、前記複数の第１電極は、それぞれ導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記複数の第２電極は、それぞれ導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部を含む周縁部は、前記電極合剤層の未塗工部であり、前記第１端部においては、前記導電部が露出しており、前記第１端部以外の端部においては、前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１側面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２側面において第２端子と接続され、前記露出している第１集電体シートの絶縁部が、前記極板群の前記第１側面以外の全側面に配され、前記露出している第２集電体シートの絶縁部が、前記極板群の前記第２側面以外の全側面に配され、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子ｅという）。
【００２１】
複数の第１電極と複数の第２電極とをセパレータを介して交互に積層した極板群を有する電気化学素子であって、前記複数の第１電極は、それぞれ導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記複数の第２電極は、それぞれ導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部を含む周縁部は、前記電極合剤層の未塗工部であり、前記第１端部においては、前記導電部が露出しており、前記第１端部以外の端部においては、前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１側面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２側面において第２端子と接続され、前記露出している第１集電体シートの絶縁部が、前記極板群の前記第１側面以外の全側面に配され、前記露出している第２集電体シートの絶縁部が、前記極板群の前記第２側面以外の全側面に配され、前記第１側面には、前記第１端子と前記第２電極とを絶縁するための第１絶縁材料部が設けられており、前記第２側面には、前記第２端子と前記第１電極とを絶縁するための第２絶縁材料部が設けられており、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している電気化学素子（以下、電気化学素子ｆという）。
【００２２】
【発明の実施の形態】
実施の形態１
本実施形態に係る（ａ）少なくとも１つの第１電極、（ｂ）少なくとも１つの第２電極、および（ｃ）第１電極と第２電極との間に介在するセパレータからなる極板群を有する電気化学素子は、前記第１電極（ａ）が、第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記第２電極（ｂ）が、第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記第１集電体シートの少なくとも１つの端部が、前記第１電極合剤層の未塗工部であり、前記第２集電体シートの少なくとも１つの端部が、前記第２電極合剤層の未塗工部であり、前記第１集電体シートの未塗工部が、前記極板群の第１側面において、第１端子と接続され、前記第２集電体シートの未塗工部が、前記極板群の第２側面において、第２端子と接続され、前記第１集電体シートの未塗工部の少なくとも一部が、前記第１端子に埋没しており、前記第２集電体シートの未塗工部の少なくとも一部が、前記第２端子に埋没している点に特徴を有する。
【００２３】
各集電体シートの未塗工部が各端子に埋没していることから、例えば、極板自体を端子に埋没させた従来の電気化学素子とは異なり、電極合剤層の導電性や集電体シートの厚さに関わらず、高い集電性能を確保できる。そして、突出させた同一極性の極板の芯材と板状の集電板とを接合する場合のように、芯材と集電板との接触面積を充分に確保できないという問題も生じない。
【００２４】
第１側面と第２側面とは、電気化学素子の構造の簡略化および製造法の簡易化の観点から、互いに極板群の反対側に位置することが好ましい。例えば、複数の略四角形の極板からなる積層型の極板群の場合には、２対の平行な側面のうちの一対の各々において、第１端子と第１集電体シートの未塗工部もしくは第２端子と第２集電体シートの未塗工部が接続されることが好ましい。長尺の極板からなる捲回型の極板群の場合には、円筒形の極板群の上下底面の各々において、第１端子と第１集電体シートの未塗工部もしくは第２端子と第２集電体シートの未塗工部が接続されることが好ましい。
【００２５】
実施の形態２
本実施形態に係る（ａ）少なくとも１つの第１電極、（ｂ）少なくとも１つの第２電極、および（ｃ）第１電極と第２電極との間に介在するセパレータからなる極板群を有する電気化学素子は、前記第１電極（ａ）が、導電部と絶縁部とを有する第１集電体シートおよびこれに担持された少なくとも１つの第１電極合剤層からなり、前記第２電極（ｂ）が、導電部と絶縁部とを有する第２集電体シートおよびこれに担持された少なくとも１つの第２電極合剤層からなり、前記各集電体シートの第１端部および第２端部が、前記電極合剤層の未塗工部であり、前記第１端部および前記第２端部においては、それぞれ前記導電部および前記絶縁部が露出しており、前記露出している第１集電体シートの導電部が、前記極板群の第１側面において第１端子と接続され、前記露出している第２集電体シートの導電部が、前記極板群の第２側面において第２端子と接続され、前記露出している第１集電体シートの導電部の少なくとも一部が、前記第１端子に埋没しており、前記露出している第２集電体シートの導電部の少なくとも一部が、前記第２端子に埋没している点に特徴を有する。
【００２６】
図１に、本実施形態に係る電気化学素子の積層型極板群の縦断面図を示す。
この極板群１０は、交互に積層された複数の第１電極１５ａと複数の第２電極１５ｂからなり、第１電極１５ａと第２電極１５ｂとの間には、セパレータ１６が介在している。第１電極１５ａは、第１集電体シート１３ａおよび２つの第１電極合剤層１４ａからなり、第１集電体シート１３ａは、樹脂シート１１ａおよびその両面に設けられた所定の形状パターンを有する導電層１２ａからなる。すなわち、第１集電体シート１３ａは、導電層の形状パターンに応じて導電部と絶縁部とを有する。
【００２７】
図１においては、樹脂シートの一端部１１ｘを除く全面もしくは端部１１ｘと図１の紙面裏表に位置する端部を除く全面に導電層が設けられている。導電層の上には、第１電極合剤層が設けられている。図１の第１集電体シートにおいては、導電層を有さない樹脂シートの端部１１ｘもしくは端部１１ｘと図１の紙面裏表に位置する端部が絶縁部として機能する。端部１１ｘの反対側に位置する導電層の端部１２ｘには、導電層の露出部が残されている。
【００２８】
樹脂シートの厚さは、例えば０．５〜５００μｍであることが好ましい。また、導電層の厚さは、０．０１〜１００μｍであることが好ましい。第１電極合剤層の厚さは、特に限定されないが、例えば１〜１０００μｍであることが好ましい。
【００２９】
樹脂シートとしては、例えば、ポリエチレン、ポリプロピレン、ポリメチルペンテンなどのオレフィン系ポリマー、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリシクロヘキシレンジメチレンテレフタレート、ポリアリレートなどのエステル系ポリマー、ポリフェニレンサルファィドなどのチオエーテル系ポリマー、ポリスチレンなどの芳香族ビニル系ポリマー、ポリイミド、アラミド樹脂などの窒素含有ポリマー、ポリ４フッ化エチレン、ポリフッ化ビニリデンなどのフッ素ポリマーなどを用いることができる。これらは単独で用いてもよく、２種以上を組み合わせたコポリマー、ポリマーアロイ、ポリマーブレンドなどを用いてもよい。
【００３０】
平坦な表面を有する通常の樹脂シートを用いてもよく、穿孔体、ラス体、多孔質体、ネット、発泡体、織布、不織布などを用いてもよい。表面に凹凸を有する樹脂シートを用いることもできる。
【００３１】
導電層には、構成された電池において化学変化を起こさない電子伝導体を特に限定なく用いることができる。第１電極が正極である場合には、例えば、ステンレス鋼、アルミニウム、アルミニウム合金、チタン、炭素などを用いることができ、特に、アルミニウム、アルミニウム合金などが好ましい。第１電極が負極である場合には、例えば、ステンレス鋼、ニッケル、銅、銅合金、チタンなどを用いることができ、特に、銅、銅合金などが好ましい。
【００３２】
導電層は、例えば導電性材料を樹脂シートに蒸着させることで形成することができるが、他の方法で形成してもよい。所定の形状パターンの蒸着膜が形成されるように、樹脂シートに所定形状の開口部を有するマスクを被せてから蒸着を行うことが好ましい。
【００３３】
図１の極板群には、２種類の第２電極１５ｂ、１５ｂ’が含まれている。
２つの第１電極１５ａで挟持されている内部の第２電極１５ｂは、極板群における配置が逆であること以外、第１電極１５ａと同様の構造を有する。すなわち、内部の第２電極１５ｂは、第２集電体シート１３ｂおよび２つの第２電極合剤層１４ｂからなり、第２集電体シート１３ｂは、樹脂シート１１ｂおよびその両面に設けられた所定の形状パターンを有する導電層１２ｂからなる。第２集電体シートは、導電層の形状パターンに応じた導電部と絶縁部とを有する。
図１の第２集電体シートにおいては、導電層を有さない樹脂シートの端部１１ｙもしくは端部１１ｙと図１の紙面裏表に位置する端部が絶縁部として機能する。端部１１ｙの反対側に位置する導電層の端部１２ｙには、導電層の露出部が残されている。
【００３４】
最外部の２つの第２電極１５ｂ’は、樹脂シート１１ｂの両面ではなく、片面に導電層１２ｂと第２電極合剤層１４ｂが設けられていること以外、内部の第２電極と同様の構造を有する。
【００３５】
第１集電体シートの導電層の露出部は、前記極板群の第１側面（図１左側）に配されており、その反対側の絶縁部は、前記極板群の第２側面（図１右側）に配されている。図１では、第１側面と前記第２側面とが、互いに前記極板群の反対側に位置しているが、側面の配置はこれに限定されるわけではない。一方、第２集電体シートの導電層の露出部は、前記極板群の第１側面に配されており、その反対側の絶縁部は、前記極板群の第２側面に配されている。
【００３６】
図１では、同様の構造を有する第１電極と第２電極とが、互いに逆向きに配置されている。従って、第１集電体シートの導電層の露出部は、第２集電体シートの絶縁部と隣接し、第２集電体シートの導電層の露出部は、第１集電体シートの絶縁部と隣接している。このような配置であれば、第１電極と第２電極との短絡を防止することが容易である。複数の第１集電体シートまたは第２集電体シートの導電層の露出部を互いに接続し、並列接続の高容量電池を得ることも容易である。ただし、短絡を確実に防止する観点からは、幅０．００１ｍｍ以上、好ましくは０．１ｍｍ以上の絶縁部を電極に設けることが好ましい。
【００３７】
図１に示されるように、露出している集電体シートの導電部の少なくとも一部を埋没させた第１端子１７ａもしくは第２端子１７ｂを得る方法は、特に限定されないが、例えば、半溶融状態の導電性微粒子を極板群の第１側面もしくは第２側面に吹き付けることにより、形成することができる。導電性材料の被膜の厚さは、例えば０．０１〜１ｍｍ程度で十分である。
【００３８】
良好な集電状態を得るためには、露出している集電体シートの導電部が第１端子もしくは第２端子の内部に、できるだけ深くまで埋没していることが好ましく、０．００１〜１ｍｍの深さまで埋没していることが好ましく、０．０１〜１ｍｍの深さまで埋没していることが、さらに好ましい。半溶融状態の導電性微粒子を極板群の第１側面もしくは第２側面に吹き付ける方法以外に、導電性ペーストの塗布やメッキなどの方法を用いることもできる。
【００３９】
第１側面および第２側面には、それぞれ第１端子と第２電極とを絶縁するための第１絶縁材料部１８ａおよび第２端子と第１電極とを絶縁するための第２絶縁材料部１８ｂを設けることが好ましい。第１側面には、第２集電体シートの絶縁部が配され、第２側面には、第１集電体シートの絶縁部が配されているため、絶縁材料部を設けなくても短絡を防止することは容易であるが、絶縁材料部を設けることで二次電池の信頼性は大幅に向上する。絶縁材料部の厚さは、特に限定されないが、０．００１ｍｍ以上、さらには０．０１ｍｍ以上であることが好ましい。絶縁材料部を形成する方法は、特に限定されないが、例えばスクリーン印刷法により、ペースト状もしくは液状の絶縁材料を所定位置に塗布することにより、形成することができる。また、フィルム状もしくはテープ状の絶縁材料を所定位置に貼り付けたりすることにより、絶縁材料部を形成することができる。
【００４０】
絶縁材料部に用いる絶縁材料としては、樹脂、ガラス組成物、セラミックスなどが挙げられる。また、織布や不織布に樹脂を含浸させた複合物などを用いることもできる。樹脂には、熱可塑性樹脂を用いてもよく、熱硬化性樹脂を用いてもよい。熱硬化性樹脂を用いる場合には、樹脂の塗膜を加熱して硬化させる工程を要する。
【００４１】
絶縁材料部に用いることのできる樹脂としては、ポリエチレン、ポリプロピレン、ポリメチルペンテンなどのオレフィン系ポリマー、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリシクロヘキシレンジメチレンテレフタレート、ポリアリレート、ポリカーボネートなどのエステル系ポリマー、ポリエチレンオキシド、ポリプロピレンオキシド、ポリアセタール、ポリフェニレンエーテル、ポリエーテルエーテルケトン、ポリエーテルイミドなどのエーテル系ポリマー、ポリスルホン、ポリエーテルスルホンなどのスルホン系ポリマー、ポリアクリロニトリル、ＡＳ樹脂、ＡＢＳ樹脂などのアクリロニトリル系ポリマー、ポリフェニレンサルファィドなどのチオエーテル系ポリマー、ポリスチレンなどの芳香族ビニル系ポリマー、ポリイミド、アラミド樹脂などの窒素含有ポリマー、ポリ４フッ化エチレン、ポリフッ化ビニリデンなどのフッ素ポリマー、ポリメタクリル酸メチルなどのアクリル系ポリマーなどを用いることができる。これらは単独で用いてもよく、２種以上を組み合わせたコポリマー、ポリマーアロイ、ポリマーブレンドなどを用いてもよい。また、加熱やＵＶ照射により重合固化して得られるポリマーを用いてもよい。
【００４２】
図１では、第１電極合剤層よりも第２電極合剤層の方が、大きな面積を有している。リチウムイオン二次電池の場合、第１電極合剤層を正極とし、第２電極合剤層を負極とするこのような構造を採用することが好ましい。一方、第１電極合剤層を負極とし、第２電極合剤層を正極とする場合には、第２電極合剤層よりも第１電極合剤層の面積を大きくすることが好ましい。
【００４３】
上記のような極板群は、多くの場合、電解液とともに所定のケースに収容して用いられる。電解液は、電池の種類に応じて異なるが、リチウムイオン二次電池の場合には、非水溶媒にリチウム塩を溶解させて調製した電解液が用いられる。ケースの形状、材質などは特に限定されない。
【００４４】
次に、上記のような積層型極板群の製造法の一例について、図２を参照しながら説明する。
（イ）第１電極の作製
所望数の集電体シートを与え得る大きさの樹脂シート２１ａを準備する。次いで、樹脂シート２１ａの両面の同じ位置に、複数の所定の形状パターンの導電層を設ける。例えば、所定形状の導電層を、図２に示すように複数行、複数列に樹脂シート上に形成する。このような導電層は、樹脂シートにマトリックス状の開口部を有するマスクを被せ、開口部から露出する樹脂シート部分に金属を蒸着させることにより得ることができる。
【００４５】
樹脂シート２１ａには、電極２つ分の大きさの導電層を複数個形成する。すなわち２ｎ個の電極を得ようとするときには、樹脂シートに片面あたりｎ個の導電層を形成する。次に、各導電層の上に、第１電極合剤層２２ａを２つずつ形成する。２つの第１電極合剤層の間には、合剤を有さない導電層の露出部２３ａを残しておく。
【００４６】
第１電極合剤層は、第１電極合剤からなるペーストを、導電層の中央部を除く全面に塗工することにより形成される。塗工方法は特に限定されないが、スクリーン印刷、パターン塗工などを採用することが好ましい。このとき合剤からなるペーストが塗工されなかった導電層の露出部は、極板群の構成後には、第１端子との接続部２４ａとなる。図２には、３行３列の電極合剤層が描かれているが、通常はより大きな集電体シート上に、より多くの導電層と電極合剤層が形成される。第１電極合剤は、第１電極の活物質、導電材、結着剤などを、分散媒と混合することにより調製される。その後、ペーストの塗膜を乾燥し、乾燥後の塗膜をローラで圧延して、合剤密度が高められる。
【００４７】
第１電極がリチウムイオン二次電池の正極である場合、活物質としては、例えば、リチウム含有遷移金属酸化物を好ましく用いることができる。リチウム含有遷移金属酸化物としては、例えば、Ｌｉ_ｘＣｏＯ_ｚ、Ｌｉ_ｘＮｉＯ_ｚ、Ｌｉ_ｘＭｎＯ_ｚ、Ｌｉ_ｘＣｏ_ｙＮｉ_１−ｙＯ_ｚ、Ｌｉ_ｘＣｏ_ｆＶ_１−ｆＯ_ｚ、Ｌｉ_ｘＮｉ_１−ｙＭ_ｙＯ_ｚ（Ｍ＝Ｔｉ、Ｖ、Ｍｎ、Ｆｅ）、Ｌｉ_ｘＣｏ_ａＮｉ_ｂＭ_ｃＯ_ｚ（Ｍ＝Ｔｉ、Ｍｎ、Ａｌ、Ｍｇ、Ｆｅ、Ｚｒ）、Ｌｉ_ｘＭｎ_２Ｏ_４、Ｌｉ_ｘＭｎ_{２（１−ｙ）}Ｍ_２ｙＯ_４（Ｍ＝Ｎａ、Ｍｇ、Ｓｃ、Ｙ、Ｆｅ、Ｃｏ、Ｎｉ、Ｔｉ、Ｚｒ、Ｃｕ、Ｚｎ、Ａｌ、Ｐｂ、Ｓｂ）などを挙げることができる。ただし、ｘ値は電池の充放電により、０≦ｘ≦１．２の範囲で変化する。また、０≦ｙ≦１、０．９≦ｆ≦０．９８、１．９≦ｚ≦２．３、ａ＋ｂ＋ｃ＝１、０≦ａ≦１、０≦ｂ≦１、０≦ｃ＜１である。これらは単独で用いてもよく、２種以上を組み合わせて用いてもよい。
【００４８】
第１電極がリチウムイオン二次電池の負極である場合、活物質としては、例えば、リチウム、リチウム合金、金属間化合物、炭素材料、リチウムイオンを吸蔵・放出可能な有機化合物や無機化合物、金属錯体、有機高分子化合物などを好ましく用いることができる。これらは単独で用いてもよく、２種以上を組み合わせて用いてもよい。炭素材料としては、コークス、熱分解炭素、天然黒鉛、人造黒鉛、メソカーボンマイクロビーズ、黒鉛化メソフェーズ小球体、気相成長炭素、ガラス状炭素、炭素繊維（ポリアクリロニトリル系、ピッチ系、セルロース系、気相成長系）、不定形炭素、有機化合物焼成体などが挙げられる。これらのうちでは、特に、天然黒鉛や人造黒鉛が好ましい。
【００４９】
導電材には、例えば、アセチレンブラックなどのカーボンブラック、黒鉛などが用いられる。また、結着剤には、例えば、ポリフッ化ビニリデン、ポリテトラフルオロエチレンなどのフッ素樹脂、アクリル系樹脂、スチレンブタジエンゴム、エチレンプロピレンターポリマーなどを用いることができる。
【００５０】
極板群において第２集電体シートの導電層の露出部と隣接することになる第１電極合剤層の周縁部、すなわち極板群の第２側面に配されることになる第１電極合剤層の周縁部に沿って絶縁材料を塗工する。ここでもパターン塗工を行うことが好ましい。このような絶縁材料の塗工は必ずしも必要ではなく、任意に行えばよいが、絶縁材料を塗工した方が短絡の可能性を低減することができる。第１電極合剤層の周縁部のその他の部分にも、絶縁材料を被覆してもよいが、第１端子との接続部となる導電層の露出部は残しておく。図１のような極板群を得る場合には、少なくとも極板群の第２側面に配されることになる第１電極合剤層の周縁部に絶縁材料を塗工する。塗工された絶縁材料は、極板群において、第１絶縁材料部を形成する。
【００５１】
（ロ）第２電極の作製
両面に第２電極合剤層を有する第２電極は、第１電極と同様の方法で作製することができる。すなわち、所望数の集電体シートを与え得る大きさの樹脂シート２１ｂの両面の同じ位置に、複数の所定の形状パターンの導電層を設け、各導電層の上に、第２電極合剤層２２ｂを２つずつ形成する。２つの第２電極合剤層の間には、合剤を有さない導電層の露出部２３ｂを残しておく。このとき合剤からなるペーストが塗工されなかった導電層の露出部は、極板群の構成後には、第２端子との接続部２４ｂとなる。片面だけに第２電極合剤層を有する第２電極についても、他方の面に導電層、第２電極合剤層および絶縁材料を設けないこと以外、上記と同様の方法で作製する。
【００５２】
（ハ）極板群の作製
作製された複数の第１電極からなる集合体と複数の第２電極からなる集合体とを、セパレータを介して積層する。このとき、第１電極の第１電極合剤層２２ａと第２電極の第２電極合剤層２２ｂとを互いに対面させ、第１電極における導電層の露出部２３ａおよび絶縁材料を、それぞれ第２電極における絶縁材料および導電層の露出部２３ｂと対面させる。両最外面には、片面だけに第２電極合剤層を有する一対の第２電極を配し、これらで内側の電極を挟持し、全体をプレスすると、複数の極板スタックからなる集合体が得られる。
【００５３】
セパレータには、ポリエチレン、ポリプロピレンなどのオレフィン系ポリマーやガラス繊維などからなる織布や不織布を用いることができる。固体電解質やゲル電解質をセパレータとして用いることもできる。固体電解質には、例えば、ポリエチレンオキサイド、ポリプロピレンオキサイドなどをマトリックス材料として用いることができる。ゲル電解質としては、例えば、後述の非水電解液をポリマー材料からなるマトリックスに保持させたものを用いることができる。マトリックスを形成するポリマー材料には、ポリエチレンオキサイド、ポリプロピレンオキサイド、ポリフッ化ビニリデン、フッ化ビニリデンとヘキサフルオロプロピレンとのコポリマーなどを用いることができる。これらは単独で用いてもよく、２種以上を組み合わせて用いてもよい。これらのうちでは、特に、フッ化ビニリデンとヘキサフルオロプロピレンとのコポリマー、ポリフッ化ビニリデンとポリエチレンオキサイドとの混合物を用いることが好ましい。
【００５４】
複数の極板スタックからなる集合体は、極板スタック毎に分割する。第１電極および第２電極は、図２に示す矢印方向に沿って切断される。導電層の露出部は、切断によって端子との接続部２４ａ、２４ｂを形成し、その反対側の樹脂シートの露出部は、切断によって絶縁部２５ａ、２５ｂを形成する。
【００５５】
従来から一般的に用いられている金属箔を集電体シートとして用いて上記のような方法を適用すると、切断時に生じる金属バリが問題となる。金属バリは、セパレータを突き破り、内部短絡を引き起こす大きな原因となる。そこで、金属バリの発生を防ぐことが重要となるが、金属バリを生じることなく金属箔を切断することは著しく困難である。一方、樹脂シートからなる集電体シートを用いる場合、切断面のほとんどが樹脂で占められているため、金属バリを生じることがない。そのため電気化学素子の信頼性は大幅に向上する。
【００５６】
第１集電体シートの導電層の露出部と第２集電体シートの絶縁部とが交互に配列する第１側面を、導電性材料の被膜で被覆すれば、第１端子が得られる。例えば、溶融もしくは半溶融状態の金属微粒子を第１側面に吹き付けることにより、第１側面を金属被膜で被覆することができる。こうして形成された金属被膜には、自動的に第１集電体シートの導電層の露出部が埋設される。第１側面に配された第２電極合剤層の端面には、絶縁材料が塗工されているため、金属被膜と第２電極との短絡は起こらない。第２集電体シートの導電層の露出部と第１集電体シートの絶縁部とが交互に配列する第２側面も、上記と同様に金属被膜で被覆することにより、第２端子を得ることができる。極板群の他の側面は、そのままの状態でもよいが、絶縁材料で被覆することが好ましい。
【００５７】
第１端子もしくは第２端子が正極端子となる場合には、金属微粒子としてアルミニウム粉末を用いることが好ましい。また、第１端子もしくは第２端子が負極端子となる場合には、金属微粒子として銅粉末を用いることが好ましい。
【００５８】
図３に示されるような複数の第１電極からなる集合体と複数の第２電極からなる集合体を用いて、極板群の集合体を得ることもできる。このような第１電極からなる集合体を得る場合、所望数の集電体シートを与え得る大きさの樹脂シート３１ａの両面の同じ位置に、複数列の帯状の導電層を形成する。このような導電層は、樹脂シートに帯状の開口部を有するマスクを被せ、開口部から露出する樹脂シート部分に金属を蒸着させることにより得ることができる。ここでも樹脂シート３１ａには、電極合剤層２列分の大きさの導電層を複数列形成する。すなわち２ｎ列の電極合剤層を得ようとするときには、樹脂シートに片面あたりｎ列の導電層を形成する。
【００５９】
各帯状導電層の上には、帯状の第１電極合剤層３２ａを２列ずつ形成する。２列の帯状第１電極合剤層３２ａの間には、合剤を有さない導電層の露出部３３ａを残しておく。帯状の第１電極合剤層３２ａは、上記と同様の第１電極合剤からなるペーストを、導電層の中央部を除く全面に塗工することにより形成される。塗工方法は積層型極板群の場合と同様である。ペーストが塗工されていない導電層の露出部３３ａは第１端子との接続部３４ａとなる。
【００６０】
第２電極からなる集合体を得る場合にも、所望数の集電体シートを与え得る大きさの樹脂シート３１ｂの両面の同じ位置に、複数列の帯状の導電層を設け、各導電層の上に、帯状の第２電極合剤層３２ｂを２列ずつ形成する。２列の帯状の第２電極合剤層の間には、合剤を有さない導電層の露出部３３ｂを残しておく。ペーストが塗工されていない導電層の露出部は第２端子との接続部３４ｂとなる。
【００６１】
このような極板群の集合体を、図３に示す矢印方向に沿って極板スタックごとに分割すると、導電層の露出部は、切断によって端子との接続部３４ａ、３４ｂを形成し、その反対側の樹脂シートの露出部は、切断によって絶縁部３５ａ、３５ｂを形成する。こうして得られた極板スタックの４つの側面においては、各集電体シートの端部とセパレータの端部とが面一に配されているが、第１側面と第２側面においては、異なる極性の電極の導電部同士が各側面において対面することはない。他の側面には、電極合剤層の断面が露出することになるが、これらの側面は、絶縁材料で被覆することにより、短絡を防止することができる。
【００６２】
得られた極板群は、必要に応じて所定形状のケースに所定の電解液とともに収容される。ケースには、例えば、ステンレス鋼板、アルミニウム板などを所定形状に加工したもの、両面に樹脂被膜を有するアルミニウム箔（アルミニウムラミネートシート）、樹脂ケースなどが用いられる。電気化学素子が、例えばリチウムイオン二次電池の場合、電解液には、非水溶媒にリチウム塩を溶解させたものが用いられる。電解液におけるリチウム塩濃度は、例えば０．５〜１．５ｍｏｌ／Ｌとすることが好ましい。
【００６３】
非水溶媒には、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネートなどの環状カーボネート、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、エチルプロピルカーボネート、メチルプロピルカーボネート、メチルイソプロピルカーボネート、ジプロピルカーボネートなどの非環状カーボネート、蟻酸メチル、酢酸メチル、プロピオン酸メチル、プロピオン酸エチルなどの脂肪族カルボン酸エステル、γ−ブチロラクトン、γ−バレロラクトンなどのγ−ラクトン、１，２−ジメトキシエタン、１，２−ジエトキシエタン、エトキシメトキシエタンなどの非環状エーテル、テトラヒドロフラン、２−メチル−テトラヒドロフランなどの環状エーテル、ジメチルスルホキシド、１，３−ジオキソラン、リン酸トリメチル、リン酸トリエチル、リン酸トリオクチルなどのアルキルリン酸エステルやそれらのフッ化物などを用いることができる。これらは複数種を組み合わせて用いることが好ましい。特に、環状カーボネートと非環状カーボネートを含む混合物、環状カーボネートと非環状カーボネートと脂肪族カルボン酸エステルを含む混合物などが好ましい。
【００６４】
リチウム塩には、ＬｉＰＦ_６、ＬｉＢＦ_４、ＬｉＣｌＯ_４、ＬｉＡｌＣｌ_４、ＬｉＳｂＦ_６、ＬｉＳＣＮ、ＬｉＣｌ、ＬｉＣＦ_３ＳＯ_３、ＬｉＣＦ_３ＣＯ_２、ＬｉＡｓＦ_６、ＬｉＮ（ＣＦ_３ＳＯ_２）_２、Ｌｉ_２Ｂ_１０Ｃｌ_１０、ＬｉＮ（Ｃ_２Ｆ_５ＳＯ_２）_２、ＬｉＰＦ_３（ＣＦ_３）_３、ＬｉＰＦ_３（Ｃ_２Ｆ_５）_３などを用いることができる。これらは単独で用いてもよく、２種以上を組み合わせて用いてもよいが、少なくともＬｉＰＦ６を用いることが好ましい。
【００６５】
上記のような製造法によれば、例えば、縦１〜３００ｍｍ、幅１〜３００ｍｍ、厚さ０．０１〜２０ｍｍの範囲であれば、任意の大きさの極板群を効率よく製造することができる。
【００６６】
次に、図４に示すような捲回型極板群の製造法の一例について説明する。図４は、第１電極を中心に描かれた捲回型極板群の部分的な概念図であり、さらに外周側の合剤層や極板等は省略されている。
（イ）第１電極の作製
捲回型極板群に用いる第１電極は、帯状の形状を有すること以外、積層型極板群に用いる第１電極と同様の構造を有する。第１電極の製造法は積層型の場合とほぼ同様である。例えば、図３に示したのと同様の第１電極からなる集合体を作製し、上記と同様に、極板群の第２側面に配されることになる第１電極合剤層の周縁部に沿って絶縁材料を塗工する。この部分は、極板群において、第２集電体シートの導電層の露出部と隣接することになる。
（ロ）第２電極の作製
図３に示したのと同様の第２電極からなる集合体を作製する。
【００６７】
（ハ）極板群の作製
第１電極からなる集合体と第２電極からなる集合体とを、セパレータ４０を介して捲回する。このとき帯状の第１電極合剤層３２ａと第２電極合剤層３２ｂとを互いに対面させ、第１電極における導電層の露出部および絶縁材料を、それぞれ第２電極における絶縁材料および導電層の露出部と対面させる。このようにすれば、交互に逆向きに配列した複数の捲回型極板群からなる長尺筒状の集合体が得られる。
【００６８】
長尺筒状の集合体は、極板群ごとに分割する。こうして得られた極板群の一方の側面（底面）には、第１集電体シートの導電層の露出部と第２集電体シートの絶縁部とが交互に、同心円状に配列している。他方の側面（底面）には、第２集電体シートの導電層の露出部と第１集電体シートの絶縁部とが交互に、同心円状に配列している。
【００６９】
第１集電体シートの導電層の露出部が配列している底面および第２集電体シートの導電層の露出部が配列している底面を、上記と同様に、それぞれ導電性材料の被膜で被覆することにより、第１端子４１および第２端子４２を形成することができる。第１端子側では、第２電極合剤層の端面に絶縁材料が塗工されているため、導電性材料の被膜と第２電極との短絡は起こらないし、第２端子側では、第１電極合剤層の端面に絶縁材料が塗工されているため、導電性材料の被膜と第１電極との短絡は起こらない。
【００７０】
【実施例】
《実施例１》
本実施例では、以下の要領で積層型のリチウムイオン二次電池を作製した。
（イ）第１電極の作製
横１９８ｍｍ、縦２８２ｍｍ、厚さ７μｍのポリエチレンテレフタレート（以下、ＰＥＴという）のシートを準備した。次いで、マトリックス状の開口部を有するマスクを用いて、ＰＥＴシートの両面の同じ位置に、３行６列に配列する複数の矩形（６５ｍｍ×４６ｍｍ）の銅の蒸着膜を形成した。銅の蒸着膜の厚さは、０．１μｍとした。
【００７１】
活物質の球状黒鉛（黒鉛化メソフェーズ小球体）１００重量部と、結着剤のスチレンブタジエンゴム３重量部と、分散媒である適量のカルボキシメチルセルロース水溶液とを混合することにより、第１電極合剤からなるペーストを調製した。
このペーストを各蒸着膜の中央部を除く全面に塗工した。その結果、各蒸着膜の上に、３２ｍｍ×４６ｍｍの第１電極合剤層が２つずつ形成された。２つの第１電極合剤層の間には、幅１ｍｍの溝状に、電極合剤層を有さない銅の蒸着膜の露出部を残した。その後、ペーストの塗膜を乾燥し、乾燥後の塗膜を厚さ７０μｍになるまでローラで圧延した。
【００７２】
得られた第１電極合剤層の周縁部のうち、蒸着膜の露出部に隣接する部分の反対側の部分に、絶縁材料として、幅０．３ｍｍのポリフッ化ビニリデンを塗工した。こうして両面に６行６列の第１電極合剤層を有する第１電極の集合体を得た。
【００７３】
（ロ）第２電極の作製
両面に第２電極合剤層を有する第２電極を作製した。
横１９８ｍｍ、縦２８２ｍｍ、厚さ７μｍのＰＥＴシートを準備した。次いで、マトリックス状の開口部を有するマスクを用いて、ＰＥＴシートの両面の同じ位置に、３行６列に配列する複数の矩形（６４ｍｍ×４５ｍｍ）のアルミニウムの蒸着膜を形成した。Ａｌ蒸着膜の厚さは、０．１μｍとした。
【００７４】
活物質のコバルト酸リチウム（ＬｉＣｏＯ_２）１００重量部と、導電材のアセチレンブラック３重量部と、結着剤のポリフッ化ビニリデン７重量部と、分散媒である適量のカルボキシメチルセルロース水溶液とを混合することにより、第２電極合剤からなるペーストを調製した。このペーストを各蒸着膜の中央部を除く全面に塗工した。その結果、各蒸着膜の上に、３１ｍｍ×４５ｍｍの第２電極合剤層が２つずつ形成された。２つの第２電極合剤層の間には、幅２ｍｍの溝状に、合剤を有さないＡｌの蒸着膜の露出部を残した。その後、ペーストの塗膜を乾燥し、乾燥後の塗膜を厚さ７０μｍになるまでローラで圧延した。
【００７５】
得られた第２電極合剤層の周縁部のうち、蒸着膜の露出部に隣接する部分の反対側の部分に、絶縁材料として、幅０．３ｍｍのポリフッ化ビニリデンを塗工した。こうして両面に６行６列の第２電極合剤層を有する第２電極の集合体を得た。
次に、片面だけに第２電極合剤層を有する第２電極を、他方の面に導電層、第２電極合剤層および絶縁材料を設けないこと以外、上記と同様の方法で作製した。
【００７６】
（ハ）極板群の作製
両面に第１電極合剤層を有する第１電極からなる集合体２つで、両面に第２電極合剤層を有する第２電極からなる集合体１つを、セパレータを介して挟持した。このとき第１電極合剤層と第２電極合剤層とを互いに対面させ、また、第１電極における蒸着膜の露出部およびポリフッ化ビニリデンを、それぞれ第２電極におけるポリフッ化ビニリデンおよび蒸着膜の露出部と対面させた。両最外面に、片面だけに第２電極合剤層を有する一対の第２電極を配し、これらで内側の電極を挟持し、全体をプレスした。その結果、複数の極板スタックからなる集合体が得られた。
【００７７】
切断位置を、第１電極における蒸着膜の露出部の中心、第２電極における蒸着膜の露出部の中心に合わせて、複数の極板スタックからなる集合体を極板スタック毎に分割した。その結果、一連の塗工・積層工程により、一度に３６個もの極板スタックを得ることができた。こうして得られた極板スタックの４つの側面においては、各集電体シートの端部とセパレータの端部とが面一に配されていた。
【００７８】
１つの側面（第１側面）には、第１集電体シートの蒸着膜の露出部と第２集電体シートのＰＥＴの露出部が交互に配列していた。その反対側の第２側面には、第２集電体シートの蒸着膜の露出部と第１集電体シートのＰＥＴの露出部が交互に配列していた。残りの２つの側面には、各集電体シートのＰＥＴの露出部が配列していた。
【００７９】
第１集電体シートの銅の蒸着膜の露出部と第２集電体シートのＰＥＴの露出部とが交互に配列する第１側面に、半溶融状態の銅微粒子を吹き付けた。その結果、第１側面に、厚さ０．５ｍｍの銅膜が形成された。銅の蒸着膜の露出部は、銅膜の内部に深さ０．２ｍｍまで埋没していた。この銅膜はそのまま負極端子として用いた。
【００８０】
第２集電体シートのＡｌの蒸着膜の露出部と第１集電体シートのＰＥＴの露出部とが交互に配列する第２側面に、半溶融状態のアルミニウム微粒子を吹き付けた。その結果、第２側面に、厚さ０．５ｍｍのアルミニウム膜が形成された。Ａｌの蒸着膜の露出部は、アルミニウム膜の内部に深さ０．２ｍｍまで埋没していた。このアルミニウム膜はそのまま正極端子として用いた。
【００８１】
こうして得られた極板群の銅膜とアルミニウム膜に、それぞれリード線を接続し、外部の充放電装置を用いて、充放電試験を行った。ここで用いた電解液は、エチレンカーボネート（ＥＣ）とエチルメチルカーボネート（ＥＭＣ）とを体積比３０：７０で混合した混合溶媒に、ＬｉＰＦ_６を１モル／Ｌの濃度で溶解して調製した。
【００８２】
［評価］
充放電は、２０℃雰囲気中で行った。
充電および放電は、それぞれ電極面積に対して２．５ｍＡ／ｃｍ^２の電流モードで行った。充電終止電圧は４．２Ｖとした。放電終止電圧は３．０Ｖとした。上記条件によって得られた電気容量は９００ｍＡｈであった。実施例１のリチウムイオン二次電池を落下させて機械的衝撃を与えても、内部短絡に由来する電圧降下などの異常は認められなかった。
【００８３】
なお、比較として、従来から用いられている銅箔からなる芯材を用いて負極を作製し、アルミニウム箔からなる芯材を用いて正極を作製したところ、同様の容量の電池を得るためには、電池の容積が実施例１のリチウムイオン二次電池の１．２倍となった。このことから、本発明によれば、電気化学素子の容量あたりのエネルギー密度を、従来よりも高められることが明らかとなった。
【００８４】
《実施例２》
本実施例では、以下の要領で捲回型のリチウムイオン二次電池を作製した。
（イ）第１電極の作製
横１９８ｍｍ、縦５０６ｍｍ、厚さ７μｍのポリエチレンテレフタレート（以下、ＰＥＴという）のシートを準備した。次いで、マトリックス状の開口部を有するマスクを用いて、ＰＥＴシートの両面の同じ位置に、３列に配列する複数の帯状（６５ｍｍ×５０６ｍｍ）の銅の蒸着膜を形成した。銅の蒸着膜の厚さは、０．１μｍとした。
【００８５】
活物質の球状黒鉛（黒鉛化メソフェーズ小球体）１００重量部と、結着剤のスチレンブタジエンゴム３重量部と、分散媒である適量のカルボキシメチルセルロース水溶液とを混合することにより、第１電極合剤からなるペーストを調製した。このペーストを各蒸着膜の中央部を除く全面に塗工し、各蒸着膜の上に、３２ｍｍ×５０６ｍｍの帯状の第１電極合剤層を２列ずつ形成した。２列の帯状の第１電極合剤層の間には、幅１ｍｍの溝状に、第１電極合剤を有さない銅の蒸着膜の露出部を残した。その後、ペーストの塗膜を乾燥し、乾燥後の塗膜を厚さ７０μｍになるまでローラで圧延した。
【００８６】
第１電極合剤層の周縁部のうち、蒸着膜の露出部に隣接する部分の反対側の部分に、絶縁材料として、幅０．３ｍｍのポリフッ化ビニリデンを塗工した。こうして、両面に６列の帯状の第１電極合剤層を有する第１電極の集合体を得た。
【００８７】
（ロ）第２電極の作製
両面に帯状の第２電極合剤層を有する第２電極を作製した。
横１９８ｍｍ、縦５０６ｍｍ、厚さ７μｍのＰＥＴシートを準備した。次いで、マトリックス状の開口部を有するマスクを用いて、ＰＥＴシートの両面の同じ位置に、３列に配列する複数の帯状（６４ｍｍ×５０６ｍｍ）のアルミニウムの蒸着膜を形成した。Ａｌ蒸着膜の厚さは、０．１μｍとした。
【００８８】
活物質のコバルト酸リチウム（ＬｉＣｏＯ_２）１００重量部と、導電材のアセチレンブラック３重量部と、結着剤のポリフッ化ビニリデン７重量部と、分散媒である適量のカルボキシメチルセルロース水溶液とを混合することにより、第２電極合剤からなるペーストを調製した。このペーストを各蒸着膜の中央部を除く全面に塗工し、各蒸着膜の上に、３１ｍｍ×５０６ｍｍの帯状の第２電極合剤層を２列ずつ形成した。２列の第２電極合剤層の間には、幅２ｍｍの溝状に、第２電極合剤を有さないＡｌの蒸着膜の露出部を残した。その後、ペーストの塗膜を乾燥し、乾燥後の塗膜を厚さ７０μｍになるまでローラで圧延した。
【００８９】
第２電極合剤層の周縁部のうち、蒸着膜の露出部に隣接する部分の反対側の部分に、絶縁材料として、幅０．３ｍｍのポリフッ化ビニリデンを塗工した。こうして、両面に６列の第２電極合剤層を有する第２電極の集合体を得た。
【００９０】
（ハ）極板群の作製
第１電極の集合体と、第２電極の集合体とを、セパレータを介して重ねてから捲回した。このとき、第１電極合剤層と第２電極合剤層とを互いに対面させ、第１電極における蒸着膜の露出部およびポリフッ化ビニリデンを、それぞれ第２電極におけるポリフッ化ビニリデンおよび蒸着膜の露出部と対面させた。その結果、交互に逆向きに配列した複数の捲回型極板群からなる長尺筒状の集合体が得られた。
【００９１】
複数の捲回型極板群からなる集合体は、第１電極における蒸着膜の露出部の中心、第２電極における蒸着膜の露出部の中心で切断して、極板群毎に分割した。その結果、一連の塗工・捲回工程により、一度に６個もの極板群を得ることができた。
【００９２】
第１集電体シートの銅の蒸着膜の露出部と第２集電体シートのＰＥＴ樹脂部とが交互に配列する側面には、半溶融状態の銅微粒子を吹き付けた。ただし、極板群の内部に電解液を注入するための注入孔を設けるために、該当箇所にマスクを被せた。その結果、前記側面に、厚さ０．５ｍｍの銅膜が形成された。このとき、銅の蒸着膜の露出部が、銅膜の内部に深さ０．２ｍｍまで埋没していた。この銅膜は、そのまま負極端子として用いた。
【００９３】
第２集電体シートのＡｌの蒸着膜の露出部と第１集電体シートのＰＥＴ樹脂部とが交互に配列する側面には、半溶融状態のアルミニウム微粒子を吹き付けた。ただし、極板群の内部に電解液を注入するための注入孔を設けるために、該当箇所にマスクを被せた。その結果、前記側面に、厚さ０．５ｍｍのアルミニウム膜が形成された。このとき、Ａｌの蒸着膜の露出部が、アルミニウム膜の内部に深さ０．２ｍｍまで埋没していた。このアルミニウム膜は、そのまま正極端子として用いた。
【００９４】
こうして得られた極板群をステンレス鋼製の円筒型電池ケースに収容し、極板群底面の銅膜をケースの内底面に接続した。極板群上面のアルミニウム膜は、アルミニウムリードを介して、周囲に絶縁ガスケットを配した封口板の裏側に接続した。次いで、電解液をケース内に注ぎ、電解液を極板群の内部に含浸させた。その後、封口板でケースの開口部を封口し、円筒型電池を完成した。ここで用いた電解液は、エチレンカーボネート（ＥＣ）とエチルメチルカーボネート（ＥＭＣ）とを体積比３０：７０で混合した混合溶媒に、ＬｉＰＦ_６を１モル／Ｌの濃度で溶解して調製した。
【００９５】
《比較例１》
従来と同様の方法で、捲回型のリチウムイオン二次電池を作製した。
すなわち、３１×５０６ｍｍの帯状のアルミニウム箔およびその両面に担持された実施例２と同じ組成・厚さの正極合剤層からなる正極を作製した。また、３２×５０６ｍｍの帯状の銅箔およびその両面に担持された実施例２と同じ組成・厚さの負極合剤層からなる負極を作製した。ただし、それぞれの極板には、集電タブを接続するための電極合剤層の未塗工部を設け、そこに集電タブを接続した。これらの正極と負極とを、セパレータを介して捲回し、極板群を作製した。
【００９６】
こうして得られた極板群を、実施例２で用いたものより直径が１．２倍大きなステンレス鋼製の円筒型電池ケースに収容し、正極リードをケースの内底面に溶接した。また、負極リードは、周囲に絶縁ガスケットを配した封口板の裏側に接続した。次いで、電解液をケース内に注ぎ、実施例２と同様の電解液を極板群の内部に含浸させた。その後、封口板でケースの開口部を封口し、円筒型電池を完成した。なお、比較例１で実施例２よりも大きな電池ケースを要したのは、集電タブが極板群の内部に介在していることから極板群の直径が増加したためである。実施例２および比較例１の電池の容量は同じであるが、比較例１の電池は、実施例２の電池よりも一回り大きくなった。
【００９７】
［評価］
実施例２および比較例１の電池の充放電を、それぞれ２０℃雰囲気中で行った。
充電および放電は、それぞれ電極面積に対して２．５ｍＡ／ｃｍ^２の電流モードで行った。充電終止電圧は４．２Ｖとした。放電終止電圧は３．０Ｖとした。上記条件によって得られた実施例２および比較例１の電池の電気容量は、いずれも９００ｍＡｈであった。
【００９８】
次に、２０℃雰囲気中で、実施例２および比較例１の電池の充電を、電極面積に対して２．５ｍＡ／ｃｍ^２の電流モードで充電終止電圧４．２Ｖまで行い、０．２Ｃ（０．５ｍＡ／ｃｍ^２）の電流値で放電した。その後、再び実施例２および比較例１の電池の充電を、上記と同じ電流モードで、充電終止電圧４．２Ｖまで行い、２Ｃ（５ｍＡ／ｃｍ^２）の電流値で放電した。その結果、実施例２の電池の場合、２Ｃで放電したときの容量は０．２Ｃで放電したときの容量の９０％であったが、比較例１の電池の場合、２Ｃで放電したときの容量は０．２Ｃで放電したときの容量の８０％であった。実施例２のリチウムイオン二次電池を落下させて機械的衝撃を与えても、内部短絡に由来する電圧降下などの異常は認められなかったが、比較例１の電池では若干の電圧降下が認められた。
【００９９】
【発明の効果】
上述のように、本発明によれば、構造が簡略であり、高出力であり、信頼性が高く、高い電気容量を有する電気化学素子を提供することができる。そして、本発明によれば、同時に複数の電気化学素子を効率的に製造することができる。このような電気化学素子を含む非水電解液二次電池を用いることにより、信頼性の高い携帯電話、携帯情報端末機器、カムコーダ、パーソナルコンピュータ、ＰＤＡ、携帯音響機器、電気自動車、ロードレベリング用電源などの機器を提供することが可能となる。
【図面の簡単な説明】
【図１】本発明に係る積層型極板群の縦断面図である。
【図２】第１電極からなる集合体と第２電極からなる集合体の切断箇所を示す概念図である。
【図３】別の第１電極からなる集合体と別の第２電極からなる集合体の切断箇所を示す概念図である。
【図４】本発明に係る捲回型極板群の縦断面概念図である。
【符号の説明】
１０極板群
１１ａ、ｂ樹脂シート
１１ｘ、ｙ樹脂シートの端部
１２ａ、ｂ導電層
１２ｘ、ｙ導電層の端部
１３ａ第１集電体シート
１３ｂ第２集電体シート
１４ａ第１電極合剤層
１４ｂ第２電極合剤層
１５ａ第１電極
１５ｂ、ｂ’ 第２電極
１６セパレータ
１７ａ第１端子
１７ｂ第２端子
１８ａ第１絶縁材料部
１８ｂ第２絶縁材料部
２１ａ、ｂ樹脂シート
２２ａ第１電極合剤層
２２ｂ第２電極合剤層
２３ａ、ｂ導電層の露出部
２４ａ第１端子との接続部
２４ｂ第２端子との接続部
２５ａ、ｂ絶縁部
３１ａ、ｂ樹脂シート
３２ａ帯状の第１電極合剤層
３２ｂ帯状の第２電極合剤層
３３ａ、ｂ導電層の露出部
３４ａ第１端子との接続部
３４ｂ第２端子との接続部
３５ａ、ｂ絶縁部
４０セパレータ
４１第１端子
４２第２端子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrochemical device, and more particularly to an improvement in a current collecting structure of an electrode group used for a secondary battery having a high energy density such as a lithium ion secondary battery.
[0002]
[Prior art]
With the miniaturization and weight reduction of electronic and electric devices, demands for miniaturization and weight reduction of electrochemical elements such as secondary batteries are increasing. On the other hand, the current secondary battery has a complicated internal structure, and there is a limit to improving the electric capacity of a product per fixed volume. In some cases, the complicated structure hinders improvement in battery reliability. For example, a current collecting tab or a current collecting lead connected to the electrode may prevent a uniform electrode reaction on the electrode surface. If a metal burr larger than usual occurs on the cut surface of the lead, an internal short circuit may occur.
[0003]
The secondary battery has an electrode group including a positive electrode, a negative electrode, and a separator. The electrode group includes a stacked type and a wound type. A stacked electrode plate group is obtained by alternately stacking a positive electrode and a negative electrode via a separator. The wound electrode plate group is obtained by winding a long positive electrode and a negative electrode via a separator. These electrode plates usually have side surfaces on which the ends of the positive electrode and the negative electrode are arranged flush. In order to extract electricity from such a side without causing a short circuit, a current collecting tab and a current collecting lead are required.
[0004]
In a battery that requires high output, the positive electrode protrudes from one of the side surfaces of the electrode plate group, and the negative electrode protrudes from the side surface opposite to the side surface, without passing through a current collecting tab or a current collecting lead. It has been proposed to extract electricity directly from each side. For example, in a battery having a stacked electrode plate group, a technique has been proposed in which protruded electrode plates of the same polarity are integrally joined using a predetermined metal member (for example, see Patent Document 1). For a battery having a wound type electrode plate group, a technique has been proposed in which a protruding core material of electrode plates of the same polarity and a plate-shaped current collector plate are joined (for example, see Patent Document 2).
[0005]
[Patent Document 1]
JP 2001-126707 A
[Patent Document 2]
JP 2000-294222 A
[0006]
[Problems to be solved by the invention]
However, when the current collecting tabs and current collecting leads are placed inside the electrode group, the structure of the electrode group becomes uneven and complicated, so that the volume efficiency is reduced and the energy density of the electrode group is reduced. Or the electrode reaction becomes non-uniform, thereby lowering the reliability of the electrochemical device. Internal short circuits may occur due to metal burrs of the current collecting tabs and current collecting leads.
[0007]
In the method of projecting the positive electrode from one of the side surfaces of the electrode plate group, projecting the negative electrode from the side surface opposite to the side surface, and integrally projecting the protruded electrode plates of the same polarity using a predetermined metal member, There is a problem that the manufacturing process is complicated and the current collecting performance is reduced because the conductivity of the protruding portion of the electrode plate is low. For example, due to the contact between the electrode mixture layer having low conductivity and the metal member, sufficient current collection cannot be performed, and when the electrode core material in contact with the metal member and the end face is thin, the current collection performance is further reduced. . In the case where the protruding core material of the electrode plate of the same polarity is joined to the plate-shaped current collector plate, it is difficult to secure a contact area between the core material and the current collector plate, and high output cannot be achieved. There is a problem.
[0008]
[Means for Solving the Problems]
The present invention has been made in view of the above situation. According to the present invention, it is possible to provide an electrochemical device having high output, a simple structure, high reliability, and high electric capacity. Further, according to the present invention, a plurality of electrochemical devices can be efficiently manufactured at the same time.
[0009]
That is, the present invention provides an electrode plate group including (a) at least one first electrode, (b) at least one second electrode, and (c) a separator interposed between the first electrode and the second electrode. Wherein the first electrode (a) comprises a first current collector sheet and at least one first electrode mixture layer carried on the first current collector sheet, and the second electrode (b) comprises: A second current collector sheet and at least one second electrode mixture layer carried on the second current collector sheet, and at least one end of the first current collector sheet is uncoated with the first electrode mixture layer. At least one end of the second current collector sheet is an uncoated portion of the second electrode mixture layer, and the uncoated portion of the first current collector sheet is On the first side surface of the plate group, the uncoated portion of the second current collector sheet is connected to the first terminal, The second current collector sheet is connected to a second terminal on the second side surface, and at least a part of an uncoated portion of the first current collector sheet is buried in the first terminal. The present invention relates to an electrochemical element (hereinafter, referred to as an electrochemical element X) in which at least a part of an uncoated portion of the body sheet is embedded in the second terminal.
[0010]
The present invention is also an electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween, wherein the plurality of first electrodes are each a first electrode. A current collector sheet and at least one first electrode mixture layer carried on the current collector sheet, wherein the plurality of second electrodes are respectively a second current collector sheet and at least one second electrode mixture layer carried on the second current collector sheet; At least one end of each of the first current collector sheets is an uncoated portion of the first electrode mixture layer, and at least one end of each of the second current collector sheets Is an uncoated portion of the second electrode mixture layer, an uncoated portion of each of the first current collector sheets is connected to a first terminal on a first side surface of the electrode plate group, The uncoated portion of each second current collector sheet contacts the second terminal on the second side surface of the electrode plate group. At least a part of the uncoated portion of the first current collector sheet is buried in the first terminal, and at least a part of the uncoated portion of the second current collector sheet is The present invention relates to an electrochemical device buried in two terminals (hereinafter, referred to as an electrochemical device Y).
[0011]
The present invention also provides an electrode plate group comprising (a) at least one first electrode, (b) at least one second electrode, and (c) a separator interposed between the first electrode and the second electrode. Wherein the first electrode (a) comprises a first current collector sheet having a conductive portion and an insulating portion, and at least one first electrode mixture layer carried on the first current collector sheet; The second electrode (b) includes a second current collector sheet having a conductive portion and an insulating portion and at least one second electrode mixture layer carried on the second current collector sheet, and a first end of each of the current collector sheets. The part and the second end are uncoated parts of the electrode mixture layer, and the conductive part and the insulating part are exposed at the first end and the second end, respectively. The exposed conductive portion of the first current collector sheet is attached to the first side surface of the electrode plate group. The exposed first conductive material of the second current collector sheet is connected to the second terminal on the second side surface of the electrode plate group, and the exposed first current collector is connected to the first terminal. At least a portion of the conductive portion of the sheet is buried in the first terminal, and at least a portion of the conductive portion of the exposed second current collector sheet is buried in the second terminal. It relates to a chemical element (hereinafter, referred to as an electrochemical element Z).
[0012]
The present invention is also an electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween, wherein the plurality of first electrodes are each a conductive part. A first current collector sheet having at least one first electrode mixture layer supported on the first current collector sheet, and a plurality of second electrodes each having a conductive portion and an insulating portion. A current collector sheet and at least one second electrode mixture layer carried on the current collector sheet, wherein a first end and a second end of each current collector sheet are uncoated portions of the electrode mixture layer. The conductive portion and the insulating portion are exposed at the first end portion and the second end portion, respectively, and the conductive portion of the exposed first current collector sheet is connected to the electrode plate group. Is connected to a first terminal on a first side surface of the second group. The conductive portion of the body sheet is connected to the second terminal on the second side surface of the electrode plate group, and at least a part of the exposed conductive portion of the first current collector sheet is buried in the first terminal. The present invention relates to an electrochemical device (hereinafter, referred to as an electrochemical device W) in which at least a part of the exposed conductive portion of the second current collector sheet is embedded in the second terminal.
[0013]
In the electrochemical devices X, Y, Z, and W, the first side surface and the second side surface can be positioned on opposite sides of the electrode plate group.
In the electrochemical elements X, Y, Z and W, a first insulating material portion for insulating the first terminal and the second electrode is provided on the first side surface, and the first insulating material portion is provided on the second side surface. A second insulating material portion for insulating the two terminals from the first electrode may be provided.
In the electrochemical devices Y and W, an insulating material can be disposed on the side surfaces of the electrode group other than the first side surface and the second side surface.
[0014]
In the electrochemical elements Z and W, the exposed insulating portion of the first current collector sheet is disposed on the second side surface, and the exposed insulating portion of the second current collector sheet is It can be arranged on the first side.
In the electrochemical elements Z and W, a peripheral portion including a first end and a second end of each current collector sheet is an uncoated portion of the electrode mixture layer, and the first terminal or the second terminal The peripheral portion other than the connection position with the terminal can be an insulating portion.
In the electrochemical elements Z and W, the exposed portion of the insulating portion of the first current collector sheet and the exposed portion of the second current collector sheet are provided on the side surface of the electrode plate group other than the first side surface and the second side surface. An exposed portion of the insulating portion can be provided.
In each of the electrochemical elements Z and W, the electrode plate group may include an exposed portion of an insulating portion of the first current collector sheet and / or the second current collector sheet, in addition to the first side surface and the second side surface. May have a side surface on which the exposed portion of the insulating portion is disposed.
[0015]
The present invention also includes a current collector sheet having a conductive portion and an insulating portion, and at least one electrode mixture layer carried on the current collector sheet, and a first end and a second end of the current collector sheet are The present invention relates to an electrode for an electrochemical element in which the conductive portion and the insulating portion are exposed at the first end portion and the second end portion, respectively, which are uncoated portions of the electrode mixture layer. In the electrode, the first end and the second end may be located on opposite sides of the current collector sheet.
[0016]
The present invention includes, for example, the following electrochemical elements.
An electrochemical device having an electrode group in which a first electrode and a second electrode are wound via a separator, wherein the first electrode has a first current collector sheet having a conductive portion and an insulating portion, and A second current collector sheet having a conductive part and an insulating part, and at least one second electrode mixture supported on the second current collector sheet having a conductive part and an insulating part. A first end portion and a second end portion of each of the current collector sheets are uncoated portions of the electrode mixture layer, and at the first end portion and the second end portion, respectively. The conductive portion and the insulating portion are exposed, and the exposed conductive portion of the first current collector sheet is connected to a first terminal on a first bottom surface of the electrode plate group and is exposed. The conductive portion of the second current collector sheet contacts the second terminal on the second bottom surface of the electrode plate group. The exposed insulating portion of the first current collector sheet is disposed on the second bottom surface, and the exposed insulating portion of the second current collector sheet is disposed on the first bottom surface. And at least a portion of the exposed conductive portion of the first current collector sheet is buried in the first terminal, and at least a portion of the exposed conductive portion of the second current collector sheet. Is an electrochemical element buried in the second terminal (hereinafter referred to as an electrochemical element a).
[0017]
An electrochemical device having an electrode group in which a first electrode and a second electrode are wound via a separator, wherein the first electrode has a first current collector sheet having a conductive portion and an insulating portion, and A second current collector sheet having a conductive part and an insulating part, and at least one second electrode mixture supported on the second current collector sheet having a conductive part and an insulating part. A first end portion and a second end portion of each of the current collector sheets are uncoated portions of the electrode mixture layer, and at the first end portion and the second end portion, respectively. The conductive portion and the insulating portion are exposed, and the exposed conductive portion of the first current collector sheet is connected to a first terminal on a first bottom surface of the electrode plate group and is exposed. The conductive portion of the second current collector sheet contacts the second terminal on the second bottom surface of the electrode plate group. The exposed insulating portion of the first current collector sheet is disposed on the second bottom surface, the exposed insulating portion of the second current collector sheet is disposed on the first bottom surface, A first insulating material portion for insulating the first terminal and the second electrode is provided on the first bottom surface, and the second terminal, the first electrode, and the second electrode are provided on the second bottom surface. A second insulating material portion is provided to insulate the first terminal, at least a part of the exposed conductive portion of the first current collector sheet is buried in the first terminal, and An electrochemical element (hereinafter, referred to as electrochemical element b) in which at least a part of the conductive portion of the second current collector sheet is buried in the second terminal.
[0018]
An electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween, wherein the plurality of first electrodes each include a conductive portion and an insulating portion. A second current collector sheet comprising a first current collector sheet and at least one first electrode mixture layer carried thereon, wherein the plurality of second electrodes each have a conductive portion and an insulating portion; The current collector sheet comprises at least one second electrode mixture layer, and the first end and the second end of each current collector sheet are uncoated portions of the electrode mixture layer, and the first end In the portion and the second end portion, the conductive portion and the insulating portion are exposed, respectively, and the exposed conductive portion of the first current collector sheet is formed on the first side surface of the electrode plate group. The first conductive sheet is connected to the first terminal and is exposed to the second current collector sheet. Is connected to a second terminal on a second side surface of the electrode plate group, and an insulating portion of the exposed first current collector sheet is disposed on the second side surface, and the exposed second current collector sheet is disposed on the second side surface. An insulating portion of the current collector sheet is disposed on the first side surface, and at least a part of the exposed conductive portion of the first current collector sheet is buried in the first terminal. An electrochemical element (hereinafter, referred to as an electrochemical element c) in which at least a part of the conductive portion of the second current collector sheet is buried in the second terminal.
[0019]
An electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween, wherein the plurality of first electrodes each include a conductive portion and an insulating portion. A second current collector sheet comprising a first current collector sheet and at least one first electrode mixture layer carried thereon, wherein the plurality of second electrodes each have a conductive portion and an insulating portion; The current collector sheet comprises at least one second electrode mixture layer, and the first end and the second end of each current collector sheet are uncoated portions of the electrode mixture layer, and the first end In the portion and the second end portion, the conductive portion and the insulating portion are exposed, respectively, and the exposed conductive portion of the first current collector sheet is formed on the first side surface of the electrode plate group. The first conductive sheet is connected to the first terminal and is exposed to the second current collector sheet. Is connected to a second terminal on a second side surface of the electrode plate group, and an insulating portion of the exposed first current collector sheet is disposed on the second side surface, and the exposed second current collector sheet is disposed on the second side surface. An insulating portion of the electric body sheet is disposed on the first side surface, and the first side surface is provided with a first insulating material portion for insulating the first terminal and the second electrode; The second side surface is provided with a second insulating material portion for insulating the second terminal and the first electrode, and at least a part of the exposed conductive portion of the first current collector sheet. Is embedded in the first terminal, and at least a part of the exposed conductive portion of the second current collector sheet is embedded in the second terminal. d).
[0020]
An electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween, wherein the plurality of first electrodes each include a conductive portion and an insulating portion. A second current collector sheet comprising a first current collector sheet and at least one first electrode mixture layer carried thereon, wherein the plurality of second electrodes each have a conductive portion and an insulating portion; The peripheral portion including the at least one second electrode mixture layer supported and including the first end and the second end of each of the current collector sheets is an uncoated portion of the electrode mixture layer, At the first end, the conductive portion is exposed, and at an end other than the first end, the insulating portion is exposed, and the first current collector sheet is exposed. A conductive portion connected to a first terminal on a first side surface of the electrode plate group; The conductive portion of the second current collector sheet is connected to the second terminal on the second side surface of the electrode plate group, and the exposed insulating portion of the first current collector sheet is formed of the electrode plate group. The insulating portions of the exposed second current collector sheet disposed on all side surfaces other than the first side surface are disposed on all the side surfaces other than the second side surface of the electrode plate group and are exposed. At least a portion of the conductive portion of the first current collector sheet is buried in the first terminal, and at least a portion of the exposed conductive portion of the second current collector sheet is connected to the second terminal. A buried electrochemical element (hereinafter referred to as an electrochemical element e).
[0021]
An electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween, wherein the plurality of first electrodes each include a conductive portion and an insulating portion. A second current collector sheet comprising a first current collector sheet and at least one first electrode mixture layer carried thereon, wherein the plurality of second electrodes each have a conductive portion and an insulating portion; The peripheral portion including the at least one second electrode mixture layer supported and including the first end and the second end of each of the current collector sheets is an uncoated portion of the electrode mixture layer, At the first end, the conductive portion is exposed, and at an end other than the first end, the insulating portion is exposed, and the first current collector sheet is exposed. A conductive portion connected to a first terminal on a first side surface of the electrode plate group; The conductive portion of the second current collector sheet is connected to the second terminal on the second side surface of the electrode plate group, and the exposed insulating portion of the first current collector sheet is formed of the electrode plate group. The insulating portions of the exposed second current collector sheet are arranged on all side surfaces other than the first side surface, and the insulating portions of the exposed second current collector sheet are arranged on all side surfaces other than the second side surface of the electrode plate group. Is provided with a first insulating material portion for insulating the first terminal and the second electrode, and on the second side surface, for insulating the second terminal and the first electrode. A second insulating material portion is provided, at least a part of the exposed conductive portion of the first current collector sheet is buried in the first terminal, and the exposed second current collector sheet is provided. At least a part of the conductive portion of the body sheet is embedded in the second terminal in an electrochemical element (hereinafter referred to as an electrochemical element f). .
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiment 1
(A) At least one first electrode, (b) at least one second electrode, and (c) an electrode group including a separator interposed between the first electrode and the second electrode according to the present embodiment. In the electrochemical device, the first electrode (a) includes a first current collector sheet and at least one first electrode mixture layer supported on the first current collector sheet, and the second electrode (b) includes a second current collector sheet. An electrical conductor sheet and at least one second electrode mixture layer carried thereon, wherein at least one end of the first current collector sheet is an uncoated portion of the first electrode mixture layer. At least one end of the second current collector sheet is an uncoated portion of the second electrode mixture layer, and an uncoated portion of the first current collector sheet is formed of the electrode plate group. In the first aspect, an uncoated portion of the second current collector sheet, which is connected to a first terminal, is provided in the electrode group. In the second side surface, at least a part of the uncoated portion of the first current collector sheet is buried in the first terminal, and is connected to the second terminal, and the uncoated portion of the second current collector sheet is uncoated. It is characterized in that at least a part of the processing portion is buried in the second terminal.
[0023]
Since the uncoated portion of each current collector sheet is buried in each terminal, for example, unlike the conventional electrochemical element in which the electrode plate itself is buried in the terminal, the conductivity of the electrode mixture layer and the current collector are different. High current collecting performance can be ensured regardless of the thickness of the electric conductor sheet. Further, there is no problem that the contact area between the core material and the current collector plate cannot be sufficiently secured as in the case where the protruding core material of the electrode plate having the same polarity and the plate-shaped current collector plate are joined.
[0024]
The first side surface and the second side surface are preferably located on opposite sides of the electrode plate group from the viewpoint of simplification of the structure of the electrochemical element and simplification of the manufacturing method. For example, in the case of a laminated electrode group including a plurality of substantially rectangular electrode plates, the uncoated surface of the first terminal and the first current collector sheet is provided on each of a pair of two parallel side surfaces. It is preferable that an uncoated portion of the second current collector sheet be connected to the second terminal or the second terminal. In the case of a wound electrode plate group composed of long electrode plates, the first terminal and the uncoated portion of the first current collector sheet or the second terminal are located at the upper and lower bottom surfaces of the cylindrical electrode plate group. It is preferable that the terminal and the uncoated portion of the second current collector sheet are connected.
[0025]
Embodiment 2
(A) At least one first electrode, (b) at least one second electrode, and (c) an electrode group including a separator interposed between the first electrode and the second electrode according to the present embodiment. In the electrochemical device, the first electrode (a) includes a first current collector sheet having a conductive portion and an insulating portion, and at least one first electrode mixture layer supported on the first current collector sheet, and the second electrode (B) comprises a second current collector sheet having a conductive portion and an insulating portion, and at least one second electrode mixture layer carried on the second current collector sheet, and the first end portion and the second end portion of each current collector sheet. Two ends are uncoated portions of the electrode mixture layer, and at the first end and the second end, the conductive portion and the insulating portion are exposed, respectively. The conductive portion of the first current collector sheet is located on the first side surface of the electrode plate group. A conductive portion of the exposed second current collector sheet connected to a terminal is connected to a second terminal on a second side surface of the electrode plate group, and a conductive portion of the exposed first current collector sheet is connected to the second terminal. At least a part of the portion is buried in the first terminal, and at least a part of the exposed conductive portion of the second current collector sheet is buried in the second terminal. Have.
[0026]
FIG. 1 is a longitudinal sectional view of a stacked electrode group of the electrochemical device according to the present embodiment.
The electrode plate group 10 includes a plurality of first electrodes 15a and a plurality of second electrodes 15b that are alternately stacked, and a separator 16 is interposed between the first electrodes 15a and the second electrodes 15b. . The first electrode 15a includes a first current collector sheet 13a and two first electrode mixture layers 14a. The first current collector sheet 13a has a predetermined shape pattern provided on the resin sheet 11a and both surfaces thereof. Of the conductive layer 12a. That is, the first current collector sheet 13a has a conductive portion and an insulating portion according to the shape pattern of the conductive layer.
[0027]
In FIG. 1, the conductive layer is provided on the entire surface except for one end 11x of the resin sheet or on the entire surface except for the end 11x and the end located on the front and back of FIG. The first electrode mixture layer is provided on the conductive layer. In the first current collector sheet of FIG. 1, the end 11x or the end 11x of the resin sheet having no conductive layer and the end located on the front and back of FIG. 1 function as an insulating portion. An exposed portion of the conductive layer is left at an end 12x of the conductive layer located on the opposite side of the end 11x.
[0028]
The thickness of the resin sheet is preferably, for example, 0.5 to 500 μm. Further, the thickness of the conductive layer is preferably 0.01 to 100 μm. The thickness of the first electrode mixture layer is not particularly limited, but is preferably, for example, 1 to 1000 μm.
[0029]
Examples of the resin sheet include olefin-based polymers such as polyethylene, polypropylene, and polymethylpentene; ester-based polymers such as polyethylene terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, and polyarylate; and thioether-based polymers such as polyphenylene sulfide. Polymers, aromatic vinyl polymers such as polystyrene, nitrogen-containing polymers such as polyimide and aramid resin, and fluoropolymers such as polytetrafluoroethylene and polyvinylidene fluoride can be used. These may be used alone, or a copolymer, a polymer alloy, a polymer blend or the like in which two or more kinds are combined may be used.
[0030]
A normal resin sheet having a flat surface may be used, or a perforated body, lath body, porous body, net, foam, woven fabric, nonwoven fabric, or the like may be used. A resin sheet having an uneven surface can also be used.
[0031]
For the conductive layer, an electronic conductor that does not cause a chemical change in the configured battery can be used without particular limitation. When the first electrode is a positive electrode, for example, stainless steel, aluminum, an aluminum alloy, titanium, carbon, or the like can be used, and particularly, aluminum, an aluminum alloy, or the like is preferable. When the first electrode is a negative electrode, for example, stainless steel, nickel, copper, a copper alloy, titanium, or the like can be used, and particularly, copper, a copper alloy, or the like is preferable.
[0032]
The conductive layer can be formed, for example, by depositing a conductive material on a resin sheet, but may be formed by another method. It is preferable to perform the vapor deposition after covering the resin sheet with a mask having an opening having a predetermined shape so that a vapor deposition film having a predetermined shape pattern is formed.
[0033]
The electrode group of FIG. 1 includes two types of second electrodes 15b and 15b '.
The inner second electrode 15b sandwiched between the two first electrodes 15a has the same structure as the first electrode 15a, except that the arrangement in the electrode group is reversed. That is, the inner second electrode 15b is composed of the second current collector sheet 13b and the two second electrode mixture layers 14b, and the second current collector sheet 13b is formed of the resin sheet 11b and the predetermined surfaces provided on both surfaces thereof. Of the conductive layer 12b having the following pattern. The second current collector sheet has a conductive part and an insulating part according to the shape pattern of the conductive layer.
In the second current collector sheet of FIG. 1, the end 11y of the resin sheet having no conductive layer or the end 11y and the end located on the front and back of FIG. 1 function as an insulating portion. An exposed portion of the conductive layer is left at an end 12y of the conductive layer located on the opposite side of the end 11y.
[0034]
The outermost two second electrodes 15b 'have the same structure as the inner second electrode except that the conductive layer 12b and the second electrode mixture layer 14b are provided on one surface, not on both surfaces of the resin sheet 11b. Having.
[0035]
The exposed portion of the conductive layer of the first current collector sheet is disposed on the first side surface (the left side in FIG. 1) of the electrode plate group, and the opposite insulating portion is provided on the second side surface (the left side surface of the electrode plate group). (Right side in FIG. 1). In FIG. 1, the first side surface and the second side surface are located on opposite sides of the electrode plate group, but the arrangement of the side surfaces is not limited to this. On the other hand, the exposed portion of the conductive layer of the second current collector sheet is disposed on the first side surface of the electrode plate group, and the insulating portion on the opposite side is disposed on the second side surface of the electrode plate group. I have.
[0036]
In FIG. 1, a first electrode and a second electrode having the same structure are arranged in opposite directions. Therefore, the exposed portion of the conductive layer of the first current collector sheet is adjacent to the insulating portion of the second current collector sheet, and the exposed portion of the conductive layer of the second current collector sheet is formed of the first current collector sheet. Adjacent to the insulation. With such an arrangement, it is easy to prevent a short circuit between the first electrode and the second electrode. It is also easy to connect the exposed portions of the conductive layers of the plurality of first current collector sheets or the second current collector sheets to each other to obtain a parallel-connected high-capacity battery. However, from the viewpoint of reliably preventing a short circuit, it is preferable to provide the electrode with an insulating portion having a width of 0.001 mm or more, preferably 0.1 mm or more.
[0037]
As shown in FIG. 1, a method for obtaining the first terminal 17 a or the second terminal 17 b in which at least a part of the exposed conductive portion of the current collector sheet is buried is not particularly limited. It can be formed by spraying the conductive fine particles in the state on the first side surface or the second side surface of the electrode plate group. The thickness of the coating of the conductive material is, for example, about 0.01 to 1 mm.
[0038]
In order to obtain a good current collecting state, it is preferable that the exposed conductive portion of the current collector sheet is buried as deep as possible in the first terminal or the second terminal, and 0.001 to 1 mm Is preferably buried to a depth of 0.01 to 1 mm, and more preferably to a depth of 0.01 to 1 mm. In addition to the method of spraying the conductive particles in a semi-molten state onto the first side surface or the second side surface of the electrode plate group, a method such as application or plating of a conductive paste may be used.
[0039]
A first insulating material portion 18a for insulating the first terminal and the second electrode and a second insulating material portion 18b for insulating the second terminal and the first electrode are provided on the first side surface and the second side surface, respectively. Is preferably provided. Since the insulating portion of the second current collector sheet is disposed on the first side surface and the insulating portion of the first current collector sheet is disposed on the second side surface, short-circuiting can be performed without providing an insulating material portion. It is easy to prevent this, but the reliability of the secondary battery is greatly improved by providing the insulating material portion. The thickness of the insulating material portion is not particularly limited, but is preferably 0.001 mm or more, and more preferably 0.01 mm or more. The method for forming the insulating material portion is not particularly limited, but the insulating material portion can be formed by, for example, applying a paste or liquid insulating material to a predetermined position by a screen printing method. Further, the insulating material portion can be formed by attaching a film-shaped or tape-shaped insulating material to a predetermined position.
[0040]
Examples of the insulating material used for the insulating material portion include a resin, a glass composition, and ceramics. Further, a composite material in which a woven fabric or a nonwoven fabric is impregnated with a resin can be used. As the resin, a thermoplastic resin or a thermosetting resin may be used. When a thermosetting resin is used, a step of heating and curing the resin coating film is required.
[0041]
Examples of resins that can be used for the insulating material portion include olefin-based polymers such as polyethylene, polypropylene, and polymethylpentene; polyethylene-based terephthalate, polybutylene terephthalate, polycyclohexylene dimethylene terephthalate, polyarylate, and ester-based polymers such as polycarbonate; Ether polymers such as ethylene oxide, polypropylene oxide, polyacetal, polyphenylene ether, polyetheretherketone, and polyetherimide; sulfone polymers such as polysulfone and polyethersulfone; acrylonitrile polymers such as polyacrylonitrile, AS resin and ABS resin; and polyphenylene Thioether polymers such as sulfide, aromatic vinyl polymers such as polystyrene Chromatography, polyimide, nitrogen-containing polymer, such as aramid resin, polytetrafluoroethylene, fluorine polymers such as polyvinylidene fluoride, acrylic polymers such as polymethyl methacrylate and the like. These may be used alone, or a copolymer, a polymer alloy, a polymer blend or the like in which two or more kinds are combined may be used. Further, a polymer obtained by polymerization and solidification by heating or UV irradiation may be used.
[0042]
In FIG. 1, the second electrode mixture layer has a larger area than the first electrode mixture layer. In the case of a lithium ion secondary battery, it is preferable to adopt such a structure in which the first electrode mixture layer is used as a positive electrode and the second electrode mixture layer is used as a negative electrode. On the other hand, when the first electrode mixture layer is a negative electrode and the second electrode mixture layer is a positive electrode, the area of the first electrode mixture layer is preferably larger than that of the second electrode mixture layer.
[0043]
The electrode group as described above is often used in a predetermined case together with an electrolytic solution. The electrolytic solution varies depending on the type of battery. In the case of a lithium ion secondary battery, an electrolytic solution prepared by dissolving a lithium salt in a non-aqueous solvent is used. The shape and material of the case are not particularly limited.
[0044]
Next, an example of a method for manufacturing the above-described stacked electrode group will be described with reference to FIG.
(A) Preparation of first electrode
A resin sheet 21a large enough to provide a desired number of current collector sheets is prepared. Next, a plurality of conductive layers having a predetermined shape pattern are provided at the same position on both surfaces of the resin sheet 21a. For example, conductive layers of a predetermined shape are formed on a resin sheet in a plurality of rows and a plurality of columns as shown in FIG. Such a conductive layer can be obtained by covering a resin sheet with a mask having a matrix-shaped opening and depositing a metal on the resin sheet portion exposed from the opening.
[0045]
A plurality of conductive layers each having a size corresponding to two electrodes are formed on the resin sheet 21a. That is, to obtain 2n electrodes, n conductive layers are formed on one side of the resin sheet. Next, two first electrode mixture layers 22a are formed on each conductive layer. An exposed portion 23a of the conductive layer having no mixture is left between the two first electrode mixture layers.
[0046]
The first electrode mixture layer is formed by applying a paste made of the first electrode mixture to the entire surface of the conductive layer except for the central portion. The coating method is not particularly limited, but it is preferable to adopt screen printing, pattern coating, or the like. At this time, the exposed portion of the conductive layer on which the paste made of the mixture has not been applied becomes a connection portion 24a to the first terminal after the electrode plate group is formed. Although FIG. 2 illustrates the electrode mixture layers in three rows and three columns, usually, more conductive layers and electrode mixture layers are formed on a larger current collector sheet. The first electrode mixture is prepared by mixing an active material of the first electrode, a conductive material, a binder and the like with a dispersion medium. Thereafter, the paste coating is dried, and the dried coating is rolled with a roller to increase the mixture density.
[0047]
When the first electrode is the positive electrode of a lithium ion secondary battery, for example, a lithium-containing transition metal oxide can be preferably used as the active material. As the lithium-containing transition metal oxide, for example, Li _x CoO _z , Li _x NiO _z , Li _x MnO _z , Li _x Co _y Ni _1-y O _z , Li _x Co _f V _1-f O _z , Li _x Ni _1-y M _y O _z (M = Ti, V, Mn, Fe), Li _x Co _a Ni _b M _c O _z (M = Ti, Mn, Al, Mg, Fe, Zr), Li _x Mn ₂ O ₄ , Li _x Mn _{2 (1-y)} M _2y O ₄ (M = Na, Mg, Sc, Y, Fe, Co, Ni, Ti, Zr, Cu, Zn, Al, Pb, Sb) and the like. However, the x value changes in the range of 0 ≦ x ≦ 1.2 due to charging and discharging of the battery. Also, 0 ≦ y ≦ 1, 0.9 ≦ f ≦ 0.98, 1.9 ≦ z ≦ 2.3, a + b + c = 1, 0 ≦ a ≦ 1, 0 ≦ b ≦ 1, and 0 ≦ c <1. is there. These may be used alone or in combination of two or more.
[0048]
When the first electrode is a negative electrode of a lithium ion secondary battery, examples of the active material include lithium, a lithium alloy, an intermetallic compound, a carbon material, an organic compound or an inorganic compound capable of inserting and extracting lithium ions, and a metal complex. And an organic polymer compound can be preferably used. These may be used alone or in combination of two or more. Carbon materials include coke, pyrolytic carbon, natural graphite, artificial graphite, mesocarbon microbeads, graphitized mesophase spherules, vapor-grown carbon, glassy carbon, carbon fibers (polyacrylonitrile, pitch, cellulose, Vapor-phase growth system), amorphous carbon, and an organic compound fired body. Among these, natural graphite and artificial graphite are particularly preferred.
[0049]
As the conductive material, for example, carbon black such as acetylene black, graphite, or the like is used. Further, as the binder, for example, a fluororesin such as polyvinylidene fluoride and polytetrafluoroethylene, an acrylic resin, styrene butadiene rubber, ethylene propylene terpolymer and the like can be used.
[0050]
In the electrode group, the first electrode to be arranged on the peripheral portion of the first electrode mixture layer that is adjacent to the exposed portion of the conductive layer of the second current collector sheet, that is, on the second side surface of the electrode group. An insulating material is applied along the periphery of the mixture layer. Here, it is preferable to perform pattern coating. Such application of the insulating material is not always necessary, and may be performed arbitrarily. However, applying the insulating material can reduce the possibility of a short circuit. Other portions of the peripheral portion of the first electrode mixture layer may be coated with an insulating material, but an exposed portion of the conductive layer serving as a connection portion with the first terminal is left. When obtaining the electrode group as shown in FIG. 1, an insulating material is applied to at least a peripheral portion of the first electrode mixture layer to be disposed on the second side surface of the electrode group. The applied insulating material forms a first insulating material portion in the electrode plate group.
[0051]
(B) Preparation of second electrode
The second electrode having the second electrode mixture layers on both surfaces can be manufactured in the same manner as the first electrode. That is, a plurality of conductive layers of a predetermined shape pattern are provided at the same position on both sides of a resin sheet 21b having a size capable of providing a desired number of current collector sheets, and a second electrode mixture layer is provided on each conductive layer. 22b are formed two by two. An exposed portion 23b of the conductive layer having no mixture is left between the two second electrode mixture layers. At this time, the exposed portion of the conductive layer on which the paste made of the mixture has not been applied becomes a connection portion 24b with the second terminal after the electrode group is formed. The second electrode having the second electrode mixture layer only on one side is manufactured in the same manner as described above, except that the conductive layer, the second electrode mixture layer and the insulating material are not provided on the other side.
[0052]
(C) Production of electrode plates
The fabricated assembly including the plurality of first electrodes and the assembly including the plurality of second electrodes are stacked with a separator interposed therebetween. At this time, the first electrode mixture layer 22a of the first electrode and the second electrode mixture layer 22b of the second electrode face each other, and the exposed portion 23a of the conductive layer in the first electrode and the insulating material are respectively replaced with the second material. It faces the insulating material of the electrode and the exposed portion 23b of the conductive layer. On both outermost surfaces, a pair of second electrodes having a second electrode mixture layer only on one side are arranged, and the inner electrodes are sandwiched by these, and when the whole is pressed, an assembly composed of a plurality of electrode plate stacks is formed. can get.
[0053]
A woven or nonwoven fabric made of an olefin polymer such as polyethylene or polypropylene, glass fiber, or the like can be used for the separator. A solid electrolyte or a gel electrolyte can be used as the separator. For the solid electrolyte, for example, polyethylene oxide, polypropylene oxide, or the like can be used as a matrix material. As the gel electrolyte, for example, a gel electrolyte in which a non-aqueous electrolyte described later is held in a matrix made of a polymer material can be used. As the polymer material forming the matrix, polyethylene oxide, polypropylene oxide, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, or the like can be used. These may be used alone or in combination of two or more. Among these, it is particularly preferable to use a copolymer of vinylidene fluoride and hexafluoropropylene, or a mixture of polyvinylidene fluoride and polyethylene oxide.
[0054]
An assembly made up of a plurality of electrode stacks is divided for each electrode stack. The first electrode and the second electrode are cut along the arrow direction shown in FIG. The exposed portions of the conductive layer form connection portions 24a and 24b with terminals by cutting, and the exposed portions of the resin sheet on the opposite side form insulation portions 25a and 25b by cutting.
[0055]
When the above-mentioned method is applied using a metal foil generally used conventionally as a current collector sheet, metal burrs generated at the time of cutting become a problem. Metal burrs break through the separator and are a major cause of internal short circuits. Therefore, it is important to prevent the generation of metal burrs, but it is extremely difficult to cut the metal foil without generating metal burrs. On the other hand, when a current collector sheet made of a resin sheet is used, since most of the cut surface is occupied by the resin, no metal burr occurs. Therefore, the reliability of the electrochemical device is greatly improved.
[0056]
A first terminal can be obtained by coating the first side surface on which the exposed portions of the conductive layer of the first current collector sheet and the insulating portions of the second current collector sheet are alternately arranged with a coating of a conductive material. For example, the first side surface can be covered with a metal coating by spraying molten or semi-molten metal fine particles on the first side surface. The exposed portion of the conductive layer of the first current collector sheet is automatically buried in the metal film thus formed. Since the insulating material is applied to the end surface of the second electrode mixture layer disposed on the first side surface, a short circuit between the metal film and the second electrode does not occur. The second side surface on which the exposed portions of the conductive layer of the second current collector sheet and the insulating portions of the first current collector sheet are alternately arranged is also covered with a metal coating in the same manner as described above, thereby obtaining the second terminal. be able to. The other side surface of the electrode plate group may be left as it is, but is preferably coated with an insulating material.
[0057]
When the first terminal or the second terminal is a positive terminal, it is preferable to use aluminum powder as the metal fine particles. When the first terminal or the second terminal is a negative terminal, it is preferable to use copper powder as metal fine particles.
[0058]
An assembly of electrode plates can also be obtained using an assembly consisting of a plurality of first electrodes and an assembly consisting of a plurality of second electrodes as shown in FIG. In order to obtain an aggregate including such first electrodes, a plurality of rows of strip-shaped conductive layers are formed at the same position on both surfaces of a resin sheet 31a having a size capable of providing a desired number of current collector sheets. Such a conductive layer can be obtained by covering a resin sheet with a mask having a strip-shaped opening and depositing a metal on the resin sheet portion exposed from the opening. Here, a plurality of rows of conductive layers each having a size corresponding to two rows of the electrode mixture layer are formed on the resin sheet 31a. That is, to obtain 2n rows of electrode mixture layers, n rows of conductive layers are formed on one side of the resin sheet.
[0059]
On each strip-shaped conductive layer, two strip-shaped first electrode mixture layers 32a are formed. The exposed portion 33a of the conductive layer having no mixture is left between the two rows of band-shaped first electrode mixture layers 32a. The strip-shaped first electrode mixture layer 32a is formed by applying a paste made of the same first electrode mixture as described above to the entire surface of the conductive layer except for the central portion. The coating method is the same as in the case of the laminated electrode group. The exposed portion 33a of the conductive layer on which the paste is not applied becomes a connection portion 34a with the first terminal.
[0060]
Also in the case of obtaining an aggregate composed of the second electrodes, a plurality of rows of strip-shaped conductive layers are provided at the same position on both sides of the resin sheet 31b having a size capable of providing a desired number of current collector sheets, and A band-shaped second electrode mixture layer 32b is formed on each of the two rows. An exposed portion 33b of the conductive layer having no mixture is left between the two rows of band-shaped second electrode mixture layers. The exposed portion of the conductive layer where the paste is not applied becomes a connection portion 34b with the second terminal.
[0061]
When such an assembly of electrode groups is divided for each electrode plate stack in the direction of the arrow shown in FIG. 3, the exposed portions of the conductive layer form connection portions 34a and 34b with terminals by cutting, and The exposed portions of the resin sheet on the opposite side form insulating portions 35a and 35b by cutting. In the four side surfaces of the electrode plate stack thus obtained, the end of each current collector sheet and the end of the separator are arranged flush with each other, but the first side and the second side have different polarities. The conductive portions of the electrodes do not face each other. Although the cross section of the electrode mixture layer is exposed on other side surfaces, by covering these side surfaces with an insulating material, a short circuit can be prevented.
[0062]
The obtained electrode group is accommodated in a case having a predetermined shape together with a predetermined electrolyte as needed. As the case, for example, a stainless steel plate, an aluminum plate or the like processed into a predetermined shape, an aluminum foil (aluminum laminated sheet) having a resin coating on both surfaces, a resin case, or the like is used. When the electrochemical element is, for example, a lithium ion secondary battery, an electrolyte obtained by dissolving a lithium salt in a non-aqueous solvent is used. The lithium salt concentration in the electrolytic solution is preferably, for example, 0.5 to 1.5 mol / L.
[0063]
Non-aqueous solvents include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, and vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethyl propyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, and dipropyl carbonate. Aliphatic carbonates such as cyclic carbonate, methyl formate, methyl acetate, methyl propionate, and ethyl propionate; γ-lactones such as γ-butyrolactone and γ-valerolactone; 1,2-dimethoxyethane; Acyclic ethers such as ethoxyethane and ethoxymethoxyethane, cyclic ethers such as tetrahydrofuran and 2-methyl-tetrahydrofuran, dimethylsulfoxy , 1,3-dioxolane, trimethyl phosphate, triethyl phosphate, alkyl phosphate esters and their fluorides, such as trioctyl phosphate can be used. These are preferably used in combination of a plurality of types. In particular, a mixture containing a cyclic carbonate and an acyclic carbonate, a mixture containing a cyclic carbonate, an acyclic carbonate, and an aliphatic carboxylic acid ester are preferable.
[0064]
LiPF includes LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAlCl ₄ , LiSbF ₆ , LiSCN, LiCl, LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiN (CF ₃ SO ₂ ) ₂ , Li ₂ B ₁₀ Cl ₁₀ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ ) ₃ Etc. can be used. These may be used alone or in combination of two or more, but it is preferable to use at least LiPF6.
[0065]
According to the above-described manufacturing method, for example, if the length is in the range of 1 to 300 mm, the width is 1 to 300 mm, and the thickness is 0.01 to 20 mm, it is possible to efficiently manufacture an electrode group having an arbitrary size. it can.
[0066]
Next, an example of a method for manufacturing a wound electrode group as shown in FIG. 4 will be described. FIG. 4 is a partial conceptual view of a wound electrode group drawn around the first electrode, and further omits a mixture layer, an electrode plate, and the like on the outer peripheral side.
(A) Preparation of first electrode
The first electrode used for the wound electrode group has the same structure as the first electrode used for the stacked electrode group, except that it has a strip shape. The method of manufacturing the first electrode is almost the same as that of the stacked type. For example, an aggregate composed of the first electrodes similar to that shown in FIG. 3 is manufactured, and the peripheral portion of the first electrode mixture layer to be disposed on the second side surface of the electrode plate group, as described above. Apply the insulating material along. This portion is adjacent to the exposed portion of the conductive layer of the second current collector sheet in the electrode plate group.
(B) Preparation of second electrode
An assembly composed of the same second electrodes as shown in FIG. 3 is manufactured.
[0067]
(C) Production of electrode plates
The assembly made up of the first electrode and the assembly made up of the second electrode are wound via the separator 40. At this time, the strip-shaped first electrode mixture layer 32a and the second electrode mixture layer 32b face each other, and the exposed portion of the conductive layer and the insulating material of the first electrode are respectively changed to the insulating material and the conductive layer of the second electrode. Face the exposed part. In this way, a long cylindrical aggregate composed of a plurality of wound electrode plates that are alternately arranged in the opposite direction is obtained.
[0068]
The long cylindrical aggregate is divided for each electrode plate group. On one side surface (bottom surface) of the electrode plate group thus obtained, exposed portions of the conductive layer of the first current collector sheet and insulating portions of the second current collector sheet are alternately arranged concentrically. I have. On the other side (bottom), exposed portions of the conductive layer of the second current collector sheet and insulating portions of the first current collector sheet are alternately and concentrically arranged.
[0069]
The bottom surface where the exposed portions of the conductive layers of the first current collector sheet are arranged and the bottom surface where the exposed portions of the conductive layers of the second current collector sheet are arranged are coated with a conductive material in the same manner as described above. The first terminal 41 and the second terminal 42 can be formed. On the first terminal side, since an insulating material is applied to the end surface of the second electrode mixture layer, a short circuit between the conductive material film and the second electrode does not occur. On the second terminal side, the first electrode Since the insulating material is applied to the end surface of the mixture layer, a short circuit between the coating of the conductive material and the first electrode does not occur.
[0070]
【Example】
<< Example 1 >>
In this example, a stacked lithium ion secondary battery was manufactured in the following manner.
(A) Preparation of first electrode
A sheet of polyethylene terephthalate (hereinafter, referred to as PET) having a width of 198 mm, a length of 282 mm, and a thickness of 7 μm was prepared. Next, a plurality of rectangular (65 mm × 46 mm) copper vapor-deposited films arranged in three rows and six columns were formed at the same position on both sides of the PET sheet using a mask having a matrix-shaped opening. The thickness of the copper deposition film was 0.1 μm.
[0071]
By mixing 100 parts by weight of spherical graphite (graphitized mesophase small spheres) as an active material, 3 parts by weight of styrene-butadiene rubber as a binder, and an appropriate amount of an aqueous solution of carboxymethylcellulose as a dispersion medium, the first electrode mixture is mixed. Was prepared.
This paste was applied to the entire surface of each deposited film except the central portion. As a result, two 32 mm x 46 mm first electrode mixture layers were formed on each of the deposited films. Between the two first electrode mixture layers, the exposed portion of the copper vapor deposition film having no electrode mixture layer was left in a groove shape having a width of 1 mm. Thereafter, the coating film of the paste was dried, and the dried coating film was rolled with a roller until the thickness became 70 μm.
[0072]
A 0.3 mm-wide polyvinylidene fluoride having a width of 0.3 mm was applied as an insulating material to a portion of the peripheral portion of the obtained first electrode mixture layer opposite to a portion adjacent to the exposed portion of the deposited film. Thus, an assembly of first electrodes having first electrode mixture layers of 6 rows and 6 columns on both surfaces was obtained.
[0073]
(B) Preparation of second electrode
A second electrode having a second electrode mixture layer on both surfaces was produced.
A PET sheet having a width of 198 mm, a length of 282 mm, and a thickness of 7 μm was prepared. Next, a plurality of rectangular (64 mm × 45 mm) aluminum vapor-deposited films arranged in three rows and six columns were formed at the same position on both sides of the PET sheet using a mask having a matrix-shaped opening. The thickness of the Al deposited film was 0.1 μm.
[0074]
Active material lithium cobalt oxide (LiCoO) ₂ ) 100 parts by weight, 3 parts by weight of acetylene black as a conductive material, 7 parts by weight of polyvinylidene fluoride as a binder, and an appropriate amount of an aqueous solution of carboxymethylcellulose as a dispersion medium are mixed to form the second electrode mixture. Was prepared. This paste was applied to the entire surface of each deposited film except the central portion. As a result, two second electrode mixture layers each having a size of 31 mm × 45 mm were formed on each deposited film. Between the two second electrode mixture layers, an exposed portion of a vapor-deposited Al film having no mixture was left in a groove shape having a width of 2 mm. Thereafter, the coating film of the paste was dried, and the dried coating film was rolled with a roller until the thickness became 70 μm.
[0075]
A 0.3 mm-wide polyvinylidene fluoride as an insulating material was applied to a portion of the peripheral portion of the obtained second electrode mixture layer opposite to a portion adjacent to the exposed portion of the deposited film. Thus, an assembly of second electrodes having second electrode mixture layers of 6 rows and 6 columns on both surfaces was obtained.
Next, a second electrode having the second electrode mixture layer only on one side was prepared in the same manner as described above, except that the conductive layer, the second electrode mixture layer, and the insulating material were not provided on the other side.
[0076]
(C) Production of electrode plates
One aggregate composed of the first electrodes having the first electrode mixture layers on both surfaces and one aggregate composed of the second electrodes having the second electrode mixture layers on both surfaces were sandwiched via a separator. At this time, the first electrode mixture layer and the second electrode mixture layer face each other, and the exposed portion of the vapor deposition film and the polyvinylidene fluoride of the first electrode are respectively connected to the polyvinylidene fluoride and the vapor deposition film of the second electrode. Faced with the exposed part. A pair of second electrodes having a second electrode mixture layer only on one side were arranged on both outermost surfaces, and the inside electrodes were sandwiched by these, and the whole was pressed. As a result, an aggregate composed of a plurality of electrode plate stacks was obtained.
[0077]
The assembly made up of a plurality of electrode plate stacks was divided for each electrode plate stack according to the cutting position of the center of the exposed portion of the deposited film on the first electrode and the center of the exposed portion of the deposited film on the second electrode. As a result, as many as 36 electrode plate stacks could be obtained at one time by a series of coating and laminating steps. On the four side surfaces of the electrode plate stack thus obtained, the end of each current collector sheet and the end of the separator were arranged flush.
[0078]
On one side surface (first side surface), exposed portions of the deposited film of the first current collector sheet and exposed portions of PET of the second current collector sheet were alternately arranged. On the opposite second side surface, exposed portions of the deposited film of the second current collector sheet and exposed portions of PET of the first current collector sheet were alternately arranged. The exposed portions of PET of each current collector sheet were arranged on the remaining two side surfaces.
[0079]
Copper particles in a semi-molten state were sprayed on the first side face where the exposed portions of the deposited copper film of the first current collector sheet and the exposed portions of PET of the second current collector sheet were alternately arranged. As a result, a copper film having a thickness of 0.5 mm was formed on the first side surface. The exposed portion of the copper vapor deposition film was buried inside the copper film to a depth of 0.2 mm. This copper film was used as it was as a negative electrode terminal.
[0080]
Semi-molten aluminum fine particles were sprayed on the second side face where the exposed portions of the Al vapor deposition film of the second current collector sheet and the exposed portions of PET of the first current collector sheet were alternately arranged. As a result, an aluminum film having a thickness of 0.5 mm was formed on the second side surface. The exposed portion of the Al deposition film was buried in the aluminum film to a depth of 0.2 mm. This aluminum film was used as it was as a positive electrode terminal.
[0081]
Lead wires were respectively connected to the copper film and the aluminum film of the electrode plate group thus obtained, and a charge / discharge test was performed using an external charge / discharge device. The electrolyte solution used here was LiPF in a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) mixed at a volume ratio of 30:70. ₆ Was dissolved at a concentration of 1 mol / L.
[0082]
[Evaluation]
The charge and discharge were performed in a 20 ° C. atmosphere.
The charge and discharge were each performed at 2.5 mA / cm with respect to the electrode area. ² In the current mode. The charge termination voltage was set to 4.2V. The discharge end voltage was 3.0 V. The electric capacity obtained under the above conditions was 900 mAh. Even when the lithium ion secondary battery of Example 1 was dropped and subjected to a mechanical shock, no abnormality such as a voltage drop due to an internal short circuit was observed.
[0083]
As a comparison, a negative electrode was manufactured using a core material made of a conventionally used copper foil, and a positive electrode was manufactured using a core material made of an aluminum foil. The capacity of the battery was 1.2 times that of the lithium ion secondary battery of Example 1. From this, it has been clarified that according to the present invention, the energy density per capacity of the electrochemical element can be increased as compared with the related art.
[0084]
<< Example 2 >>
In this example, a wound lithium ion secondary battery was manufactured in the following manner.
(A) Preparation of first electrode
A sheet of polyethylene terephthalate (hereinafter, referred to as PET) having a width of 198 mm, a length of 506 mm, and a thickness of 7 μm was prepared. Next, a plurality of strip-shaped (65 mm × 506 mm) copper vapor-deposited films arranged in three rows were formed at the same position on both sides of the PET sheet using a mask having a matrix-shaped opening. The thickness of the copper deposition film was 0.1 μm.
[0085]
By mixing 100 parts by weight of spherical graphite (graphitized mesophase small spheres) as an active material, 3 parts by weight of styrene-butadiene rubber as a binder, and an appropriate amount of an aqueous solution of carboxymethylcellulose as a dispersion medium, the first electrode mixture is mixed. Was prepared. This paste was applied to the entire surface of each deposited film except for the central part, and two rows of 32 mm × 506 mm band-shaped first electrode mixture layers were formed on each deposited film. An exposed portion of a copper vapor deposition film having no first electrode mixture was left in a groove shape having a width of 1 mm between the two rows of strip-shaped first electrode mixture layers. Thereafter, the coating film of the paste was dried, and the dried coating film was rolled with a roller until the thickness became 70 μm.
[0086]
A portion of the peripheral portion of the first electrode mixture layer opposite to the portion adjacent to the exposed portion of the deposited film was coated with polyvinylidene fluoride having a width of 0.3 mm as an insulating material. Thus, a first electrode aggregate having six rows of band-shaped first electrode mixture layers on both surfaces was obtained.
[0087]
(B) Preparation of second electrode
A second electrode having a band-shaped second electrode mixture layer on both surfaces was produced.
A PET sheet having a width of 198 mm, a length of 506 mm, and a thickness of 7 μm was prepared. Next, a plurality of strip-shaped (64 mm × 506 mm) aluminum vapor-deposited films arranged in three rows were formed at the same position on both sides of the PET sheet using a mask having a matrix-shaped opening. The thickness of the Al deposited film was 0.1 μm.
[0088]
Active material lithium cobalt oxide (LiCoO) ₂ ) 100 parts by weight, 3 parts by weight of acetylene black as a conductive material, 7 parts by weight of polyvinylidene fluoride as a binder, and an appropriate amount of an aqueous solution of carboxymethylcellulose as a dispersion medium are mixed to form the second electrode mixture. Was prepared. This paste was applied to the entire surface of each deposited film except for the central portion, and two rows of 31 mm × 506 mm band-shaped second electrode mixture layers were formed on each deposited film. Between the two rows of the second electrode mixture layers, an exposed portion of the deposited Al film having no second electrode mixture was left in a groove shape having a width of 2 mm. Thereafter, the coating film of the paste was dried, and the dried coating film was rolled with a roller until the thickness became 70 μm.
[0089]
A portion of the peripheral portion of the second electrode mixture layer opposite to the portion adjacent to the exposed portion of the deposited film was coated with polyvinylidene fluoride having a width of 0.3 mm as an insulating material. In this way, an aggregate of second electrodes having six rows of second electrode mixture layers on both surfaces was obtained.
[0090]
(C) Production of electrode plates
The assembly of the first electrode and the assembly of the second electrode were wound after being stacked via a separator. At this time, the first electrode mixture layer and the second electrode mixture layer face each other, and the exposed portion of the deposited film and the polyvinylidene fluoride on the first electrode are respectively exposed to the exposed portions of the polyvinylidene fluoride and the deposited film on the second electrode. Face to face. As a result, a long cylindrical aggregate consisting of a plurality of wound electrode plates arranged alternately in the opposite direction was obtained.
[0091]
An assembly made up of a plurality of wound electrode groups was cut at the center of the exposed portion of the deposited film on the first electrode and the center of the exposed portion of the deposited film on the second electrode, and divided for each electrode group. As a result, as many as six electrode plates could be obtained at one time by a series of coating and winding steps.
[0092]
Semi-molten copper fine particles were sprayed on the side surfaces of the first current collector sheet where the exposed portions of the copper vapor-deposited film and the PET resin portions of the second current collector sheet were alternately arranged. However, in order to provide an injection hole for injecting the electrolytic solution into the inside of the electrode plate group, a mask was put on the corresponding portion. As a result, a copper film having a thickness of 0.5 mm was formed on the side surface. At this time, the exposed portion of the copper deposition film was buried inside the copper film to a depth of 0.2 mm. This copper film was used as it was as a negative electrode terminal.
[0093]
Semi-molten aluminum particles were sprayed on the side surfaces of the second current collector sheet where the exposed portions of the deposited Al film were alternately arranged with the PET resin portions of the first current collector sheet. However, in order to provide an injection hole for injecting the electrolytic solution into the inside of the electrode plate group, a mask was put on the corresponding portion. As a result, an aluminum film having a thickness of 0.5 mm was formed on the side surface. At this time, the exposed portion of the deposited Al film was buried in the aluminum film to a depth of 0.2 mm. This aluminum film was used as it was as a positive electrode terminal.
[0094]
The electrode group thus obtained was housed in a cylindrical battery case made of stainless steel, and the copper film on the bottom surface of the electrode group was connected to the inner bottom surface of the case. The aluminum film on the upper surface of the electrode plate group was connected via an aluminum lead to the back side of a sealing plate around which an insulating gasket was disposed. Next, the electrolytic solution was poured into the case, and the electrolytic solution was impregnated inside the electrode plate group. Thereafter, the opening of the case was sealed with a sealing plate to complete a cylindrical battery. The electrolyte solution used here was LiPF in a mixed solvent of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) mixed at a volume ratio of 30:70. ₆ Was dissolved at a concentration of 1 mol / L.
[0095]
<< Comparative Example 1 >>
A wound type lithium ion secondary battery was manufactured in the same manner as in the related art.
That is, a positive electrode composed of a strip-shaped aluminum foil of 31 × 506 mm and a positive electrode mixture layer having the same composition and thickness as in Example 2 carried on both surfaces thereof was produced. Further, a negative electrode comprising a 32 × 506 mm strip-shaped copper foil and a negative electrode mixture layer having the same composition and thickness as in Example 2 carried on both surfaces thereof was produced. However, each electrode plate was provided with an uncoated portion of the electrode mixture layer for connecting the current collecting tab, and the current collecting tab was connected thereto. These positive electrode and negative electrode were wound with a separator interposed therebetween to produce an electrode plate group.
[0096]
The electrode group thus obtained was housed in a stainless steel cylindrical battery case having a diameter 1.2 times larger than that used in Example 2, and the positive electrode lead was welded to the inner bottom surface of the case. The negative electrode lead was connected to the back side of a sealing plate around which an insulating gasket was arranged. Next, the electrolytic solution was poured into the case, and the same electrolytic solution as in Example 2 was impregnated inside the electrode plate group. Thereafter, the opening of the case was sealed with a sealing plate to complete a cylindrical battery. The reason why the comparative example 1 requires a battery case larger than that of the example 2 is that the diameter of the electrode group is increased because the current collecting tab is interposed in the electrode group. Although the capacities of the batteries of Example 2 and Comparative Example 1 were the same, the battery of Comparative Example 1 was slightly larger than the battery of Example 2.
[0097]
[Evaluation]
The batteries of Example 2 and Comparative Example 1 were respectively charged and discharged in a 20 ° C. atmosphere.
The charge and discharge were each performed at 2.5 mA / cm with respect to the electrode area. ² In the current mode. The charge termination voltage was set to 4.2V. The discharge end voltage was 3.0 V. The electric capacities of the batteries of Example 2 and Comparative Example 1 obtained under the above conditions were all 900 mAh.
[0098]
Next, the batteries of Example 2 and Comparative Example 1 were charged in a 20 ° C. atmosphere by 2.5 mA / cm with respect to the electrode area. ² In a current mode of up to 4.2 V at the end-of-charge voltage of 0.2 C (0.5 mA / cm ² ). Thereafter, the batteries of Example 2 and Comparative Example 1 were again charged in the same current mode as described above to a charge end voltage of 4.2 V, and 2C (5 mA / cm) ² ). As a result, in the case of the battery of Example 2, the capacity when discharged at 2C was 90% of the capacity when discharged at 0.2C, whereas in the case of the battery of Comparative Example 1, the capacity when discharged at 2C. The capacity was 80% of the capacity when discharged at 0.2C. When the lithium ion secondary battery of Example 2 was dropped and subjected to a mechanical shock, no abnormality such as a voltage drop due to an internal short circuit was found, but a slight voltage drop was found for the battery of Comparative Example 1. Was done.
[0099]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an electrochemical device having a simple structure, high output, high reliability, and high electric capacity. According to the present invention, a plurality of electrochemical devices can be efficiently manufactured at the same time. By using a non-aqueous electrolyte secondary battery including such an electrochemical element, a highly reliable mobile phone, a portable information terminal device, a camcorder, a personal computer, a PDA, a portable audio device, an electric vehicle, a power source for road leveling Such devices can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a laminated electrode group according to the present invention.
FIG. 2 is a conceptual diagram showing cut portions of an assembly made up of a first electrode and an assembly made up of a second electrode.
FIG. 3 is a conceptual diagram showing cut portions of an assembly made of another first electrode and an assembly made of another second electrode.
FIG. 4 is a conceptual longitudinal sectional view of a wound electrode group according to the present invention.
[Explanation of symbols]
10 Electrode group
11a, b resin sheet
11x, y edge of resin sheet
12a, b conductive layer
12x, y end of conductive layer
13a 1st current collector sheet
13b 2nd current collector sheet
14a first electrode mixture layer
14b second electrode mixture layer
15a first electrode
15b, b 'second electrode
16 separator
17a 1st terminal
17b 2nd terminal
18a first insulating material section
18b Second insulating material section
21a, b resin sheet
22a first electrode mixture layer
22b Second electrode mixture layer
23a, b Exposed portion of conductive layer
24a Connection with first terminal
24b Connection to second terminal
25a, b insulation
31a, b resin sheet
32a strip-shaped first electrode mixture layer
32b belt-shaped second electrode mixture layer
33a, b Exposed portion of conductive layer
34a Connection portion with first terminal
34b Connection to the second terminal
35a, b insulation
40 separator
41 1st terminal
42 2nd terminal

Claims

An electrochemical device having (a) at least one first electrode, (b) at least one second electrode, and (c) an electrode group including a separator interposed between the first electrode and the second electrode. hand,
The first electrode (a) includes a first current collector sheet and at least one first electrode mixture layer supported on the first current collector sheet,
The second electrode (b) includes a second current collector sheet and at least one second electrode mixture layer supported on the second current collector sheet,
At least one end of the first current collector sheet is an uncoated portion of the first electrode mixture layer,
At least one end of the second current collector sheet is an uncoated portion of the second electrode mixture layer,
An uncoated portion of the first current collector sheet is connected to a first terminal on a first side surface of the electrode plate group;
An uncoated portion of the second current collector sheet is connected to a second terminal on a second side surface of the electrode plate group;
At least a part of the uncoated portion of the first current collector sheet is embedded in the first terminal,
An electrochemical device wherein at least a part of an uncoated portion of the second current collector sheet is buried in the second terminal.

The electrochemical device according to claim 1, wherein the first side surface and the second side surface are located on opposite sides of the electrode group.

A first insulating material portion for insulating the first terminal and the second electrode is provided on the first side surface, and the second terminal, the first electrode, and the second side surface are provided on the second side surface. The electrochemical device according to claim 1, further comprising a second insulating material portion for insulating the element.

An electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween,
The plurality of first electrodes each include a first current collector sheet and at least one first electrode mixture layer supported on the first current collector sheet,
The plurality of second electrodes each include a second current collector sheet and at least one second electrode mixture layer supported on the second current collector sheet,
At least one end of each of the first current collector sheets is an uncoated portion of the first electrode mixture layer,
At least one end of each of the second current collector sheets is an uncoated portion of the second electrode mixture layer,
An uncoated portion of each of the first current collector sheets is connected to a first terminal on a first side surface of the electrode plate group;
The uncoated portion of each of the second current collector sheets is connected to a second terminal on a second side surface of the electrode plate group,
At least a part of the uncoated portion of the first current collector sheet is embedded in the first terminal,
An electrochemical device wherein at least a part of an uncoated portion of the second current collector sheet is buried in the second terminal.

The electrochemical device according to claim 4, wherein the first side surface and the second side surface are located on opposite sides of the electrode group.

A first insulating material portion for insulating the first terminal and the second electrode is provided on the first side surface, and the second terminal, the first electrode, and the second side surface are provided on the second side surface. The electrochemical device according to claim 4 or 5, further comprising a second insulating material portion for insulating the substrate.

The electrochemical device according to any one of claims 4 to 6, wherein an insulating material is provided on a side surface of the electrode plate group other than the first side surface and the second side surface.

An electrochemical device having (a) at least one first electrode, (b) at least one second electrode, and (c) an electrode group including a separator interposed between the first electrode and the second electrode. hand,
The first electrode (a) includes a first current collector sheet having a conductive portion and an insulating portion, and at least one first electrode mixture layer carried on the first current collector sheet,
The second electrode (b) includes a second current collector sheet having a conductive portion and an insulating portion, and at least one second electrode mixture layer carried on the second current collector sheet,
A first end and a second end of each current collector sheet are uncoated portions of the electrode mixture layer,
At the first end and the second end, the conductive portion and the insulating portion are exposed, respectively.
The exposed conductive portion of the first current collector sheet is connected to a first terminal on a first side surface of the electrode plate group,
The exposed conductive portion of the second current collector sheet is connected to a second terminal on a second side surface of the electrode plate group,
At least a part of the exposed conductive portion of the first current collector sheet is buried in the first terminal,
An electrochemical device in which at least a part of the exposed conductive portion of the second current collector sheet is buried in the second terminal.

The exposed insulating portion of the first current collector sheet is disposed on the second side surface, and the exposed insulating portion of the second current collector sheet is disposed on the first side surface. Item 10. An electrochemical device according to Item 8.

The electrochemical device according to claim 8, wherein the first side surface and the second side surface are located on opposite sides of the electrode group.

A first insulating material portion for insulating the first terminal and the second electrode is provided on the first side surface, and the second terminal, the first electrode, and the second side surface are provided on the second side surface. The electrochemical device according to any one of claims 8 to 10, further comprising a second insulating material portion for insulating the first electrode.

A peripheral portion including a first end portion and a second end portion of each current collector sheet is an uncoated portion of the electrode mixture layer, and a peripheral portion other than a connection position with the first terminal or the second terminal. The electrochemical device according to claim 8, wherein the portion is an insulating portion.

An exposed portion of an insulating portion of the first current collector sheet and an exposed portion of an insulating portion of the second current collector sheet are disposed on side surfaces of the electrode plate group other than the first side surface and the second side surface. An electrochemical device according to any one of claims 8 to 11.

In the electrode group, an exposed portion of an insulating portion of the first current collector sheet and / or an exposed portion of an insulating portion of the second current collector sheet are disposed in addition to the first side surface and the second side surface. The electrochemical device according to any one of claims 8 to 11, wherein the electrochemical device has a side surface.

An electrochemical device having an electrode group in which a plurality of first electrodes and a plurality of second electrodes are alternately stacked with a separator interposed therebetween,
The plurality of first electrodes include a first current collector sheet having a conductive portion and an insulating portion, and at least one first electrode mixture layer supported on the first current collector sheet,
The plurality of second electrodes each include a second current collector sheet having a conductive portion and an insulating portion, and at least one second electrode mixture layer carried on the second current collector sheet,
A first end and a second end of each current collector sheet are uncoated portions of the electrode mixture layer,
At the first end and the second end, the conductive portion and the insulating portion are exposed, respectively.
The exposed conductive portion of the first current collector sheet is connected to a first terminal on a first side surface of the electrode plate group,
The exposed conductive portion of the second current collector sheet is connected to a second terminal on a second side surface of the electrode plate group,
At least a part of the exposed conductive portion of the first current collector sheet is buried in the first terminal,
An electrochemical device in which at least a part of the exposed conductive portion of the second current collector sheet is buried in the second terminal.

The exposed insulating portion of the first current collector sheet is disposed on the second side surface, and the exposed insulating portion of the second current collector sheet is disposed on the first side surface. Item 16. The electrochemical device according to Item 15,

17. The electrochemical device according to claim 15, wherein the first side surface and the second side surface are located on opposite sides of the electrode group.

A first insulating material portion for insulating the first terminal and the second electrode is provided on the first side surface, and the second terminal, the first electrode, and the second side surface are provided on the second side surface. The electrochemical device according to any one of claims 15 to 17, further comprising a second insulating material portion for insulating the first electrode.

A peripheral portion including a first end portion and a second end portion of each current collector sheet is an uncoated portion of the electrode mixture layer, and a peripheral portion other than a connection position with the first terminal or the second terminal. The electrochemical device according to claim 15, wherein the portion is an insulating portion.

An exposed portion of an insulating portion of the first current collector sheet and an exposed portion of an insulating portion of the second current collector sheet are disposed on side surfaces of the electrode plate group other than the first side surface and the second side surface. An electrochemical device according to any one of claims 15 to 18.

In the electrode group, an exposed portion of an insulating portion of the first current collector sheet and / or an exposed portion of an insulating portion of the second current collector sheet are disposed in addition to the first side surface and the second side surface. The electrochemical device according to any one of claims 15 to 18, which has a side surface.

A current collector sheet having a conductive portion and an insulating portion and at least one electrode mixture layer carried on the current collector sheet,
The first end and the second end of the current collector sheet are uncoated portions of the electrode mixture layer,
An electrode for an electrochemical device in which the conductive portion and the insulating portion are exposed at the first end and the second end, respectively.

23. The electrode for an electrochemical device according to claim 22, wherein the first end and the second end are located on opposite sides of the current collector sheet.