JP2010141156A - Solar battery module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar battery module which can prevent an entry of humidity, gas, and the like into a solar battery cell, thereby maintaining an electric power generation capability of the solar battery cell extending over a long period finely. <P>SOLUTION: This solar battery module A includes: a solar battery cell 1a in which a p electrode 11 and an n electrode 12 are formed on the back of a semiconductor substrate 1 for a back electrode type solar battery; and a wiring substrate 2a which is laminated and integrated on one face of the solar battery cell 1a, and in which p wiring 21 and n wiring 22 are formed to be electrically insulated from each other on an insulating substrate 2 containing a liquid crystal polymer. The p electrode 11 is electrically connected to the p wiring 12 through solder, and also the n electrode 12 is electrically connected to the n wiring 22 through solder. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solar cell module.

  In recent years, depletion of fossil fuels such as oil, and environmental destruction such as global warming by using them have become a global problem. In view of this, various studies have been made on the use of solar energy, wind power, hydropower, biomass, tidal currents, ocean currents, ocean currents such as waves, geothermal heat, and temperature differences as clean energy to replace fossil fuels.

  Photovoltaic power generation is particularly attracting attention as clean energy, and solar cells are being developed. In the solar cell module, solar cells are sealed on the front and back surfaces with a sealing material such as an ethylene-vinyl acetate copolymer film, and glass is used as a surface protective layer that transmits light on the front side sealing material. The plates are laminated and integrated, and the back protection sheet for solar cells is laminated and integrated on the back side sealing material as a back sheet.

Patent Document 1, a back protective sheet for a solar cell is disposed on the rear surface of the solar cell module, density contains 0.91 g / cm ³ or more 0.93 g / cm ³ or less linear low density polyethylene A back protective sheet for a solar cell comprising a first film and a second film containing polyvinylidene fluoride and polymethyl methacrylate laminated on the first film is disclosed.

  However, since the back surface protection sheet for solar cells is formed by laminating the first film and the second film, the first film and the second film may peel off over time. As a result, there is a problem that the moisture-proof property of the back protective sheet for solar cells and the permeation-preventing effect of gas such as oxygen gas are lowered. Moreover, although the method of using the material which gave moisture resistance by vapor-depositing a metal etc. on a film is also taken, there exists a problem that moisture resistance falls by the crack of a vapor deposition film.

  Moreover, in order to improve the moisture resistance of the back surface protection sheet for solar cells, a back surface protection sheet for solar cells in which a synthetic resin film and a metal foil such as an aluminum foil are laminated and integrated has been proposed. Corrosion occurs and the solar battery cells are adversely affected.

JP 2008-211034 A

  The present invention provides a solar cell module that can prevent moisture and gas from entering the solar cell and maintain the power generation capability of the solar cell well over a long period of time.

  The solar cell module of the present invention has a p-type electrode on an insulating substrate made of a liquid crystal polymer on the electrode-forming surface of a solar cell in which a p-electrode and an n-electrode are formed on the back side of a semiconductor substrate for back-electrode solar cells. A wiring board in which wiring and n wiring are formed is laminated and integrated. The p electrode and the p wiring are electrically connected via solder, and the n electrode and the n wiring are connected to each other. It is electrically connected through solder.

  In the solar cell module, the insulating substrate is formed from a single-layer sheet.

  Furthermore, in the above solar cell module, a surface protective layer that transmits light is laminated on a light incident surface of a semiconductor substrate for a back electrode type solar cell.

  In the solar cell module of the present invention, as described above, the insulating substrate is made of a liquid crystal polymer, and since the insulating substrate is excellent in moisture resistance and gas permeation resistance, separately from the conventional solar cell module, There is no need to use a back protective sheet to ensure moisture resistance and gas permeation prevention.

  Therefore, the solar cell module of the present invention has a simple structure, is excellent in manufacturing efficiency, and can be thinned. In addition, since the insulating substrate can be formed as a single layer, the moisture resistance and gas permeation resistance are not lowered due to delamination, and the solar cell module of the present invention is excellent over a long period of time. Power generation performance can be maintained. Note that the use of the back surface protection sheet is not excluded, and even when used, it is not necessary to consider moisture proof performance and gas permeation performance, so the range of selection is widened.

  Furthermore, since the insulating substrate is made of a liquid crystal polymer, it has excellent dimensional stability and is not affected by thermal contraction of the insulating substrate due to temperature changes in the usage environment, and the wiring of the solar cell electrode and wiring substrate The connection state of can be reliably maintained. Therefore, the solar cell module can maintain excellent power generation performance regardless of the temperature change of the usage environment.

  Further, since the insulating substrate is made of a liquid crystal polymer and has excellent insulating properties, the insulating state between the p wiring and the n wiring formed on the insulating substrate can be reliably maintained.

  Since the insulating substrate is made of a liquid crystal polymer, the heat-resistant temperature of the insulating substrate is higher than the soldering temperature, and the p-electrode and n-electrode on the back-surface electrode type solar cell semiconductor substrate of the solar cell, and the insulating substrate It is possible to withstand the soldering temperature when connecting and integrating the p wiring and the n wiring through solder. As a result, unlike the case where the connection is made with a low temperature curing silver paste, the short circuit caused by migration is less likely to occur, the pitch between the electrodes can be reduced, and the p-electrode and n-electrode on the solar cell have a fine pitch. Fine lines can be obtained, and the performance of the solar cell module of the present invention can be further improved. That is, the power generation capability of the solar cell module A can be improved, and the solar cell module A can be reduced in size.

  The solar cell module A of the present invention is called a back electrode type solar cell or a back contact cell, and is a solar cell module having no electrode on the light receiving surface. In the solar cell 1a, a p-electrode 11 and an n-electrode 12 are formed on the back surface of the semiconductor substrate 1 for back-electrode solar cells. As such a solar battery cell 1a, for example, a p + layer and an n + layer are formed on the back surface of the silicon substrate alternately at intervals along the back surface of the silicon substrate. A solar cell in which a dotted or linear p-electrode 11 is formed on the p + layer and a dotted n-electrode 12 is formed on the n + layer, a p + layer on the back surface of the silicon substrate, and an n + on the surface A dot-like pattern is formed on the p + layer of the semiconductor substrate 1 for the back electrode type solar cell, which is formed on the back surface side of the silicon substrate through a through-hole penetrating the front and back surfaces where the n + layer is formed on the silicon substrate. And a solar battery cell in which the n electrode 12 is formed in a dot shape on the n + layer taken out on the back side of the silicon substrate.

  The method for manufacturing the semiconductor substrate for the back electrode type solar cell by forming the p + layer and the n + layer on the back surface of the silicon substrate is not particularly limited. For example, first, a silicon oxide film is formed on the entire back surface of the silicon substrate. Then, a passivation film is formed by forming a silicon nitride film. Next, a part of the passivation film corresponding to the portion where the n + layer on the back surface of the silicon substrate is formed is removed by photoetching. Then, an n + layer is formed by diffusing the n-type dopant on the back surface of the silicon substrate exposed from the removed portion using a gas containing an n-type dopant such as phosphorus. Then, after all of the passivation film formed on the back surface of the silicon substrate is removed, a silicon oxide film is formed again on the entire back surface of the silicon substrate, and then a passivation film is formed by forming a silicon nitride film. Next, a part of the passivation film corresponding to the portion where the p + layer is formed is removed by photoetching. And the method of forming a p + layer by diffusing a p-type dopant in the back surface of the silicon substrate exposed from the removal part using the gas containing p-type dopants, such as boron, is mentioned.

  Also, a back electrode formed by forming a p + layer on the back surface of the silicon substrate and an n + layer on the front surface and taking out to the back surface side of the silicon substrate through a through-hole penetrating the front and back surfaces formed on the silicon substrate. A semiconductor substrate for a solar cell has also been proposed. As a manufacturing method, for example, Advent is called “Emitter Wrap Through”, and a through-hole penetrating the silicon substrate is formed on both sides with a laser. In addition, Kyocera Corporation is examining a metal wrap-through cell in which only the bus bar electrode is placed on the back surface. This method uses an electrode material in the through-hole formed in the silicon substrate by laser processing. In this method, the finger electrodes on the front surface of the silicon substrate and the bus bar on the back surface are electrically connected to each other, and only the bus bar electrodes that are conventionally positioned on the front surface of the silicon substrate are disposed on the back side.

  Then, the wiring substrate 2a is laminated and integrated on the back surface of the semiconductor substrate 1 for back electrode type solar cells of the solar cell 1a, that is, on the surface (electrode forming surface) on which the p electrode 11 and the n electrode 12 are formed. Yes. The wiring board 2a is formed on the insulating substrate 2 made of a single layer sheet made of a liquid crystal polymer in a state where the p wiring 21 and the n wiring 22 are electrically insulated from each other. The insulating substrate 2 may be formed by stacking and integrating a plurality of sheets made of liquid crystal polymer.

  Examples of the liquid crystal polymer include wholly aromatic liquid crystal polyesters, wholly aromatic liquid crystal polyimides, wholly aromatic liquid crystal polyester amides, and the like, and wholly aromatic liquid crystal polyesters are preferable. The wholly aromatic liquid crystal polyester is a polyester called a thermotropic liquid crystal polymer. Typical examples thereof include (1) a polymer obtained by reacting an aromatic dicarboxylic acid, an aromatic diol, and an aromatic hydroxycarboxylic acid. (2) a polymer obtained by reacting a combination of different types of aromatic hydroxycarboxylic acids, (3) a polymer obtained by reacting an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aliphatic diol, (4) Examples include polymers obtained by reacting aromatic dicarboxylic acids and aromatic diols, and (5) polymers obtained by reacting aromatic hydroxycarboxylic acids with polyesters such as polyethylene terephthalate. It is a polymer that forms an anisotropic melt. In addition, these ester derivatives may be used instead of aromatic dicarboxylic acid, aromatic diol, and aromatic hydroxycarboxylic acid. Furthermore, in the aromatic dicarboxylic acid, aromatic diol, and aromatic hydroxycarboxylic acid, the aromatic moiety may be substituted with a halogen atom, an alkyl group, an aryl group, or the like.

  Specifically, as liquid crystal polyester, type I [the following formula (1)] synthesized from parahydroxybenzoic acid (PHB), terephthalic acid and 4,4′-biphenol, PHB and 2,6-hydroxy Type II synthesized from naphthoic acid [Formula (2)], PHB, terephthalic acid, and type III synthesized from ethylene glycol [Formula (3)] can be mentioned. However, from the viewpoint of heat resistance, dimensional stability, and moisture resistance, wholly aromatic liquid crystal polyesters (type I and type II) are preferred.

  The wholly aromatic liquid crystal polyester film is commercially available from Japan Gore-Tex, Inc. under the trade name “BIAC”, for example.

  As described above, the p wiring 21 and the n wiring 22 are electrically insulated from each other on the insulating substrate 2. As a procedure for forming the p wiring 21 and the n wiring 22 on the insulating substrate 2, for example, a film made of a conductive metal such as copper is formed on one surface of the insulating substrate, and a part of the film is etched. Thus, the p wiring 21 and the n wiring 22 can be formed. The surfaces of the p wiring 21 and the n wiring 22 are coated with solder.

  A wiring substrate 2a is laminated and integrated on the back surface of the semiconductor substrate 1 for the back electrode type solar cell of the solar cell 1a so that the p wiring and the n wiring face the solar cell 1a. A p-electrode 11 formed on the back surface of the semiconductor substrate for solar cell 1 and a p-wiring 21 formed on the insulating substrate 2 are electrically connected via a solder 31, and a back-electrode solar cell The n-electrode 12 formed on the back surface of the semiconductor substrate 1 for use and the n-wiring 22 formed on the insulating substrate 2 are electrically connected via the solder 32 to constitute the solar cell module A.

  Since the insulating substrate 2 is made of a liquid crystal polymer, the heat-resistant temperature of the insulating substrate 2 is higher than the soldering temperature, and the p-electrode 11 and the n-electrode 12 on the back surface of the semiconductor substrate 1 for back-electrode solar cells and the insulating substrate 2 The upper p wiring 21 and n wiring 22 can be electrically connected and integrated through the solder 32. Therefore, unlike the case of using a low temperature curing silver paste for the connection, the p electrode 11 and the n electrode 12 on the semiconductor substrate 1 for the back electrode type solar cell can be made into fine lines and fine pitches, and the solar cell module The power generation capacity of A can be improved and the solar cell module A can be reduced in size.

  A sealing material 41 is laminated and integrated on the surface of the back electrode type solar cell semiconductor substrate 1 and also between the opposing surfaces of the back electrode type solar cell semiconductor substrate 1 and the insulating substrate 2. 42 is filled. Such a sealing material is not particularly limited, and examples thereof include an ethylene-vinyl acetate copolymer.

  Next, the p electrode 11 and the n electrode 12 on the back surface of the semiconductor substrate 1 for back electrode type solar cells and the p wiring 21 and the n wiring 22 on the insulating substrate 2 are electrically connected and integrated through the solder 32. In addition, the point of filling the sealing material 42 between the opposing surfaces of the back electrode type solar cell semiconductor substrate 1 and the insulating substrate 2 is not particularly limited.

  As the above-mentioned procedure, for example, (1) a solar cell 1a and a wiring board 2a are placed in a state where a p-electrode 11 and a p-wiring 21 face each other, and an n-electrode 12 and an n-wiring 22 face each other. A laminated body is formed by overlapping with an anisotropic conductive film containing balls interposed therebetween. The solder-plated copper core ball in the anisotropic conductive film is adjusted so as to be positioned on the p-electrode 11 and the n-electrode 12 of the solar battery cell 1a. Next, the laminate is degassed and heated to soften the anisotropic conductive film and fill the space between the solar battery cell 1a and the wiring board 2a, and by dissolving the plated copper core ball, p A method of electrically connecting the electrode 11 and the p-wiring 21 via solder and electrically connecting the n-electrode 12 and the n-wiring 22 via solder; (2) the p-wiring 21 of the wiring board 2 and Solder plating is performed on the n wiring 22 in advance. A laminated body is formed by stacking the solar cell 1a and the wiring board 2a with the p electrode 11 and the p wiring 21 facing each other and the n electrode 12 and the n wiring 22 facing each other with a film interposed therebetween. To do. Next, the laminate is degassed and heated to soften the film and fill the space between the solar cell 1a and the wiring substrate 2a, and solder plating on the p wiring 21 and the n wiring 22 A method of electrically connecting the p-electrode 11 and the p-wiring 21 via solder and also electrically connecting the n-electrode 12 and the n-wiring 22 via solder; (3) the wiring board 2; Solder plating is performed on the p wiring 21 and the n wiring 22 in advance. Next, a sealing resin is applied on the surface of the wiring board 2 where the p wiring 21 and the n wiring 22 are formed. In a vacuum, the solar cell 1a and the wiring substrate 2a are overlapped with the p electrode 11 and the p wiring 21 facing each other and the n electrode 12 and the n wiring 22 facing each other to form a laminated body. Then, after returning to atmospheric pressure, the laminate is heated to soften the sealing resin on the wiring board 2 and fill the space between the solar cells 1a and the wiring board 2a, and p wiring By melting the solder plating on 21 and n wiring 22, p electrode 11 and p wiring 21 are electrically connected via solder, and n electrode 12 and n wiring 22 are electrically connected via solder. (4) A low-residue solder paste is applied in advance on the p wiring 21 and the n wiring 22 of the wiring board 2. Next, a sealing resin is applied on the surface of the wiring board 2 where the p wiring 21 and the n wiring 22 are formed. In a vacuum, the solar cell 1a and the wiring substrate 2a are overlapped with the p electrode 11 and the p wiring 21 facing each other and the n electrode 12 and the n wiring 22 facing each other to form a laminated body. Then, after returning to atmospheric pressure, the laminate is heated to soften the sealing resin on the wiring board 2 and fill the space between the solar cells 1a and the wiring board 2a, and p wiring By melting the low-residue solder paste on the 21 and n wirings 22, the p electrode 11 and the p wiring 21 are electrically connected via solder, and the n electrode 12 and the n wiring 22 are electrically connected via solder. The method of making it connect to is mentioned.

  Further, the surface protective layer 5 is laminated and integrated on the sealing material 41 of the solar cell module A. Such a surface protective layer 5 does not impair the incidence of light on the light receiving surface of the solar cell module A, that is, the surface of the semiconductor substrate 1 for back electrode type solar cells, and protects the solar cell module A. For example, a transparent glass plate and a polyethylene terephthalate plate can be used. The surface protective layer 5 may be formed by applying a liquid material that transmits light to the surface side of the solar battery cell and curing it.

  In the solar cell module A thus obtained, as described above, the insulating substrate 2 is made of a liquid crystal polymer, and is excellent in moisture resistance and gas permeation prevention. Therefore, it is not necessary to laminate and integrate a back surface protective film separately on the back surface of the insulating substrate 2 in order to provide moisture proofing and gas permeation preventing properties, and the manufacturing efficiency of the solar cell module A can be improved by simplifying the manufacturing process. In addition, the solar cell module A can be thinned. In addition, in order to prevent the insulating substrate 2 from being damaged during transportation or installation of the solar cell module A, not to provide moisture resistance and gas permeation prevention properties, a protective sheet is provided on the back surface of the insulating substrate 2. May be laminated.

  Further, since the insulating substrate 2 is made of a liquid crystal polymer and has excellent heat resistance and dimensional stability, the p-electrode 11 and the n-electrode 12 on the semiconductor substrate 1 for back electrode solar cells can be used even at high temperatures outdoors. The connection state between the p wiring 21 and the n wiring 22 on the insulating substrate 2 can be reliably maintained, and the excellent power generation capability of the solar cell 1a can be reliably maintained over a long period of time.

It is the schematic cross section which showed the solar cell module of this invention.

Explanation of symbols

1 Semiconductor substrate for back electrode type solar cell
11 p-electrode
12 n-electrode
1a Solar cell 2 Insulating substrate
21p wiring
22n wiring
2a Wiring board
31,32 solder
41,42 Encapsulant 5 Surface protective layer A Solar cell module

Claims (3)

The p wiring and the n wiring are formed on the insulating substrate made of the liquid crystal polymer on the electrode forming surface of the solar cell in which the p electrode and the n electrode are formed on the back surface of the semiconductor substrate for the back electrode type solar battery. The p-electrode and the p-wiring are electrically connected via solder, and the n-electrode and the n-wiring are electrically connected via solder. A solar cell module characterized by being made. The solar cell module according to claim 1, wherein the insulating substrate is formed from a single-layer sheet. The solar cell module according to claim 1, wherein a surface protective layer that transmits light is laminated on a light incident surface of a semiconductor substrate for a back electrode type solar cell.

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