TWI396291B - Solar cell, apparatus and method for making same - Google Patents

Description

Solar cell, manufacturing equipment thereof and method of manufacturing same

The present invention relates to a solar cell, an apparatus and method for manufacturing the same, and more particularly to a solar cell having a flexible substrate, an apparatus and method for manufacturing the solar cell.

The solar cell mainly uses the photoelectric conversion principle, and a typical structure thereof mainly includes a substrate and a P-type semiconductor material layer and an N-type semiconductor material layer disposed on the substrate.

Photoelectric conversion refers to the process by which the radiant energy photons of the sun are converted into electrical energy by semiconductor materials (see "Grown junction GaAs solar cell", Shen, CC; Pearson, GL; Proceedings of the IEEE, Volume 64, Issue 3, March 1976 Page. (s): 384-385). When sunlight hits the semiconductor, a portion of it is reflected off the surface and the remainder is absorbed or transmitted by the semiconductor. Some of the absorbed light, of course, becomes thermal energy, while other photons collide with the valence electrons that make up the semiconductor, producing electron-hole pairs. Thus, the light energy is converted into electrical energy in the form of electron-hole pairs, and a barrier electric field is formed on both sides of the P-type and N-type interfaces, driving electrons to the N region, and holes are driven toward the P region, thereby making N There is excess electrons in the region, and there are excess holes in the P region, and a photo-generated electric field opposite to the electric field of the barrier is formed in the vicinity of the PN junction. A portion of the photogenerated electric field, in addition to offsetting the barrier electric field, also positively charges the P-type layer, the N-type semiconductor layer is negatively charged, and a thin layer between the N region and the P region produces a so-called photovoltaic electromotive force. If metal leads are soldered to the P-type layer and the N-type semiconductor layer, respectively, and the load is turned on, the external circuit passes current. The battery elements thus formed can be produced by connecting them in series and in parallel. Generate a certain voltage and current, output power.

In recent years, solar cells have been widely used in aerospace, industrial, meteorological and other fields. How to apply solar cells to daily life to solve problems such as energy shortage and environmental pollution has become a hot issue. Among them, the combination of solar cells and building materials, so that the future of large buildings or family houses to achieve self-sufficiency in electricity, is a major development direction in the future, Germany, the United States and other countries have proposed photovoltaic roofing plans.

However, the substrates of general solar cells are made of single crystal germanium, polycrystalline germanium or glass. These materials are not easily deflected and are difficult to fix on a curved surface, which limits the shape and mounting position of the solar cell panel, especially in the hope of There are many limitations when applied to modules that are combined with building materials.

In view of the above, it is necessary to provide a solar cell having a flexible substrate, an apparatus for manufacturing the same, and a method of manufacturing the same.

A solar cell comprising a flexible substrate, a back electrode, a P-type semiconductor layer, a P-N junction layer, an N-type semiconductor layer, a transparent conductive layer and a front electrode. The material of the substrate is stainless steel. The back electrode is formed on one surface of the substrate. The P-type semiconductor layer is formed on the back electrode. The P-N junction layer is formed on the P-type semiconductor layer. The N-type semiconductor layer is formed on the P-N junction layer. The transparent conductive layer is formed on the N-type semiconductor layer. The front electrode is formed on the transparent conductive layer.

An apparatus for manufacturing a solar cell, comprising a winding chamber and a coating chamber. The winding chamber is provided with a take-up reel for winding a flexible stainless steel substrate and for ejecting the substrate from the take-up reel, and a take-up reel for winding the coated substrate. a coating chamber is sequentially provided with a first sputtering zone, a first deposition zone, a second sputtering zone, and a second deposition zone, a third sputtering zone and a fourth sputtering zone, each zone being respectively provided with at least one roller, the first end of the deflectable stainless steel substrate being wound on the discharge reel, the second end of the stainless steel substrate The roller is wound on the take-up reel in turn, so that the stainless steel substrate can pass through the first sputtering zone, the first deposition zone, the second sputtering zone, the second deposition zone, the third sputtering zone, and the like from the take-up reel. The fourth sputtering zone is wound around the take-up reel. The first sputtering region is configured to form a back electrode on one surface of the substrate by a sputtering method, and the first deposition region is configured to form a P-type semiconductor layer on the back electrode by a chemical vapor deposition method, the first a second sputtering region for forming a PN junction layer on the P-type semiconductor layer by sputtering, the second deposition region for forming an N-type semiconductor layer on the PN junction layer by chemical vapor deposition, a third sputtering region is used to form a transparent conductive layer on the N-type semiconductor layer by a sputtering method, and the fourth sputtering region is used to form a front electrode on the transparent conductive layer by a sputtering method, thereby obtaining solar energy battery.

A method of manufacturing a solar cell, comprising the steps of: winding one end of a stainless steel substrate on a take-up reel, winding the other end of the stainless steel substrate on a take-up reel; and releasing the stainless steel substrate from the reel The stainless steel substrate sequentially passes through the first sputtering zone, the first deposition zone, the second sputtering zone, the second deposition zone, the third sputtering zone, and the fourth sputtering zone, thereby being wound on a reel, wherein a first sputtering region forms a back electrode on one surface of the substrate by a sputtering method, and a P-type semiconductor layer is formed on the back electrode by chemical vapor deposition in the first deposition region, and the second sputtering is performed Forming a PN junction layer on the P-type semiconductor layer by sputtering, and forming an N-type semiconductor layer on the PN junction layer by chemical vapor deposition in the second deposition region, in the third sputtering region A transparent conductive layer is formed on the N-type semiconductor layer by a sputtering method, and a front electrode is formed on the transparent conductive layer by sputtering in the fourth sputtering region, thereby obtaining a solar cell.

Compared with the prior art, the substrate of the solar cell of the present invention is a flexible stainless steel substrate, so that the solar cell can be flexed, and when it is applied to the construction field, it is easier to match the shape of the building itself. Designed into solar cells of different geometries to make the design more flexible.

10‧‧‧ solar cells

101‧‧‧Substrate

102‧‧‧ Back electrode

103‧‧‧P type semiconductor layer

104‧‧‧P-N layer

105‧‧‧N type semiconductor layer

106‧‧‧Transparent conductive layer

107‧‧‧ front electrode

1012‧‧‧ Surface of the substrate

20‧‧‧Roll coating system

202‧‧‧Winding room

204‧‧‧ Coating room

206‧‧‧Reel

208‧‧‧Reel

210‧‧‧roller

212‧‧‧guide shaft

2041‧‧‧First sputtering zone

2042‧‧‧First sedimentary zone

2043‧‧‧Second sputtering zone

2044‧‧‧Second sedimentary zone

2045‧‧‧3rd sputtering zone

2046‧‧‧4th sputtering zone

1 is a schematic cross-sectional view of a solar cell according to an embodiment of the present invention; and FIG. 2 is a cross-sectional view showing a roll coating system for manufacturing a solar cell according to an embodiment of the present invention.

The invention will be further described in detail below with reference to the accompanying drawings.

Referring to FIG. 1, a solar cell 10 includes a substrate 101 having a surface 1012. The surface 1012 of the substrate 101 is sequentially formed with a back metal contact layer 102 and a P-type semiconductor layer 103. The PN junction layer 104, the N-type semiconductor layer 105, the Transparent Conductive Oxide 106, and the Front Metal Contact Layer 107.

The substrate 101 is a stainless steel thin foil (Stainless Steel Thin Foil) having a thickness of approximately 10 μm to 100 μm. The material of the substrate 101 may be austenitic stainless steel, ferritic stainless steel, martensitic stainless steel or the like.

The material of the back electrode 102 may be silver (Ag), copper (Cu), molybdenum (Mo), aluminum (Al), copper-aluminum alloy (Cu-Al Alloy), silver-copper alloy (Ag-Cu Alloy), or copper-molybdenum. Alloy (Cu-Mo Alloy) and the like. The back electrode 102 may be formed by a sputtering method or a deposition method.

The material of the P-type semiconductor layer 103 may be a P-type amorphous silicon (Pa-Si) material, in particular, a P-type amorphous silicon with hydrogen (P-type amorphous silicon with hydrogen, referred to as Pa-Si). :H) Material. Of course, the material of the P-type semiconductor layer may also be a III-V compound or a II-VI compound, in particular, doped with aluminum (Al) or potassium (Ga). A semiconductor material of indium (In) such as aluminum aluminum nitride (AlGaN) or aluminum gallium arsenide (AlGaAs).

Preferably, the material of the P-type semiconductor layer 103 is a P-type amorphous germanium material. The amorphous germanium material absorbs light about 500 times stronger than the crystalline germanium material, so the thickness of the semiconductor layer made of the amorphous germanium material is much smaller than that of the crystalline germanium material when the photon absorption amount is the same. The thickness of the layer. And the amorphous germanium material has lower requirements on the material of the substrate. Therefore, the use of an amorphous germanium material not only saves a large amount of material, but also makes it possible to fabricate a large-area solar cell (the area of the crystalline germanium solar cell is limited by the size of the germanium wafer).

The material of the PN junction layer 104 may be a group III-V compound or a group I-III-VI compound having good bonding, such as cadmium telluride (CdTe), copper indium selenide (CuInSe ₂ ) or the like. It is also possible to use copper indium gallium selenide (CuIn _1-X GaSe ₂ , CIGS). The PN junction layer 132 is used to convert photons into electron-hole pairs and form a barrier electric field. The PN junction layer 132 can be formed by a method such as Chemical Vapor Deposition (CVD), sputtering, or the like.

The material of the N-type semiconductor layer 105 may be an N-type Amorphous Silicon (Na-Si) material, in particular, an N-type Amorphous Silicon With Hydrogen (Na-Si). :H) Material. Of course, the material of the N-type semiconductor layer 133 may also be a III-V compound or a II-VI compound, especially a semiconductor material doped with nitrogen (N), phosphorus (P), or arsenic (As), such as nitriding. Potassium (GaN) or indium gallium phosphide (InGaP).

The material of the transparent conductive layer 106 may be, for example, Indium Tin Oxide (ITO), zinc oxide (ZnO), or the like.

The material of the front electrode 107 may be silver (Ag), copper (Cu), molybdenum (Mo), aluminum (Al), copper-aluminum alloy (Cu-Al Alloy), silver-copper alloy (Ag-Cu Alloy), or copper-molybdenum. Alloy (Cu-Mo Alloy) and the like.

Compared with the prior art, the substrate 101 of the solar cell 10 of the present invention is a flexible stainless steel sheet, so that the solar cell 10 can be flexed, and when it is applied to the construction field, it is easier to design different geometric shapes in accordance with the shape of the building itself. The solar cells make the design more flexible. Moreover, the price of the stainless steel sheet is relatively cheap, so that the cost of the solar cell 10 can be reduced, which is advantageous for further widespread promotion of the solar cell 10. In addition, the solar cell 10 of the present invention can be applied not only to the construction field but also to 3C products such as spacecraft, vehicles, and mobile phones due to its flexibility and low cost.

An apparatus and method for manufacturing a solar cell 10 are described below.

Referring to FIG. 2, the roll coating system 20 includes a winding chamber 202 and a coating chamber 204. A take-up reel 206 and a take-up reel 208 are disposed in the winding chamber 202.

The coating chamber 204 includes, in order from left to right, a first sputtering region 2041, a first deposition region 2042, a second sputtering region 2043, a second deposition region 2044, a third sputtering region 2045, and a fourth sputtering region 2046.

The first sputtering region 2041, the second sputtering region 2043, the third sputtering region 2045, and the fourth sputtering region 2046 are respectively used to form the back electrode 102, the PN junction layer 104, and the transparent conductive layer of the solar cell by a sputtering method. 106 and front electrode 107. In the present embodiment, the sputtering method is preferably a direct current magnetron sputtering method (Direct Current Magnetron Sputtering). The sputtering targets (not shown) of the respective sputtering zones are selected according to different materials. For example, for the first sputtering region 2041, the sputtering target may be silver, copper, molybdenum, aluminum, copper aluminum alloy, silver copper alloy, or copper molybdenum alloy, etc., depending on the material of the back electrode 102 to be formed.

The first deposition region 2042 and the second deposition region 2044 are used to form the P-type semiconductor layer 103 and the N-type semiconductor layer 105 of the solar cell 10 by chemical vapor deposition (CVD), respectively. In the present embodiment, the deposition method is preferably plasma enhanced chemical vapor deposition (Plasma Enhanced Chemical Vapor Deposition).

At least one roller 210 is disposed in each of the sputtering zone and the deposition zone, and the roller 210 is used to support the substrate 101 to be coated. In the present embodiment, a cooling liquid (not shown) may be disposed in the roller 210 to facilitate heat dissipation of the substrate 101 so as to maintain a relatively low temperature throughout the entire coating process. A guide shaft 212 is disposed between the winding chamber 202 and the coating chamber 204, and the guide shaft 212 is used to guide the substrate 101 to be coated to advance.

The method of manufacturing a solar cell by the roll coating system 20 is as follows: Before the coating, the substrate 101 to be coated is wound between the take-up reel 206, the guide shaft 212, the roller 210, and the take-up reel 208, and the substrate 101 is a stainless steel sheet. The solar cell 10 is obtained by sequentially forming a structure such as the back electrode 102 by plating a film on the surface 1012 of the substrate 101.

When the motor (not shown) drives the take-up reel 206 to rotate clockwise, the guide shaft 212 and the roller 210 rotate counterclockwise, and the take-up reel 208 rotates clockwise. The substrate 101 from the take-up reel 206 passes through the guide shaft 212 to the first sputtering zone 2041. The roller 210 cools the substrate 101 and maintains its temperature at a suitable temperature, and performs sputtering in the first sputtering zone 2041. The back electrode 102 is formed on the surface 1012 of the substrate 101.

The take-up reel 208 continues to drive the substrate 101 forward, the portion of the substrate 101 having the back electrode 102 reaches the first deposition zone, the roller 210 cools the substrate 101 and maintains its temperature at a suitable temperature, and plasma assists in the first deposition zone 2042 The P-type semiconductor layer 103 is formed on the back electrode 102 by chemical vapor deposition.

The take-up reel 208 continues to drive the substrate 101 forward, and the portion of the substrate 101 having the back electrode 102 and the P-type semiconductor layer 103 reaches the second sputtering region 2043, and the roller 210 cools the substrate 101 and maintains its temperature at a suitable temperature. The second sputtering region is sputtered to form a PN junction layer 104 on the P-type semiconductor layer 103.

The portion of the substrate 101 having the back electrode 102, the P-type semiconductor layer 103, and the P-N junction layer 104 passes sequentially The second deposition region 2044, the third sputtering region 2045, and the fourth sputtering region 2046 sequentially form the N-type semiconductor layer 105, the transparent conductive layer 106, and the front electrode 107, thereby obtaining the solar cell 10 shown in FIG.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧ solar cells

101‧‧‧Substrate

102‧‧‧ Back electrode

103‧‧‧P type semiconductor layer

104‧‧‧P-N layer

105‧‧‧N type semiconductor layer

106‧‧‧Transparent conductive layer

107‧‧‧ front electrode

1012‧‧‧ Surface of the substrate

Claims (2)

A solar cell manufacturing apparatus comprising: a winding chamber, wherein the winding chamber is provided with a discharge reel for winding a flexible stainless steel substrate and discharging the substrate from the discharge reel, The reel is used for winding up the coated substrate; a coating chamber is sequentially provided with a first sputtering zone, a first deposition zone, a second sputtering zone, a second deposition zone, a third sputtering zone, and a fourth sputtering Each of the zones is provided with at least one roller, and the first end of the deflectable stainless steel substrate is wound on the take-up reel, and the second end of the stainless steel substrate is wound on the take-up reel through the rollers, so that the stainless steel The substrate may pass through the first sputtering zone, the first deposition zone, the second sputtering zone, the second deposition zone, the third sputtering zone and the fourth sputtering zone in order from the take-up reel, thereby being wound on the reel, The first sputtering region is configured to form a back electrode on one surface of the substrate by a sputtering method, and the first deposition region is configured to form a P-type semiconductor layer on the back electrode by a chemical vapor deposition method, the first Two sputtering zone Forming a PN junction layer on the P-type semiconductor layer by sputtering, the second deposition region for forming an N-type semiconductor layer on the PN junction layer by chemical vapor deposition, the third sputtering region A transparent conductive layer is formed on the N-type semiconductor layer by a sputtering method for forming a front electrode on the transparent conductive layer by a sputtering method, thereby obtaining a solar cell. A method for manufacturing a solar cell using the manufacturing apparatus according to claim 1, wherein the method comprises the steps of: winding one end of a stainless steel substrate on a take-up reel, and winding the other end of the stainless steel substrate through a roller Reeling the stainless steel substrate from the discharge reel so that the stainless steel substrate sequentially passes through the first sputtering zone, the first deposition zone, the second sputtering zone, the second deposition zone, the third sputtering zone, and the fourth sputtering District, from And winding on a take-up reel, wherein a back electrode is formed on one surface of the substrate by sputtering in the first sputtering region, and the first deposition region is formed on the back electrode by chemical vapor deposition a P-type semiconductor layer, a PN junction layer is formed on the P-type semiconductor layer by sputtering in the second sputtering region, and a layer is formed on the PN junction layer by chemical vapor deposition in the second deposition region An N-type semiconductor layer, a transparent conductive layer is formed on the N-type semiconductor layer by sputtering in the third sputtering region, and a front electrode is formed on the transparent conductive layer by sputtering in the fourth sputtering region Thereby obtaining a solar cell.