JPH07147424A - Method for manufacturing thin film solar cell module - Google Patents

Abstract

(57) [Abstract] [Purpose] Connection between solar cell sub-modules that are sandwiched between protective glass substrates and between the conductive film used to extract generated power and the end electrodes of the sub-module. , Use a method other than soldering, which cannot withstand the film of the flexible substrate. [Structure] An anisotropic conductive film including a metal piece is sandwiched between an end electrode and a conductive film, and the conductive film and the end electrode are connected by adhering them when the protective substrate is heated and pressed. Alternatively, conductive protrusions may be formed on the transparent electrode or conductive film with solder, and the adhesive resin film for bonding the submodule and the protective substrate may be pierced to break the conductive film and the end electrodes. Make a connection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film solar cell module in which a plurality of thin film solar cell submodules using a semiconductor thin film containing amorphous silicon as a main component are connected.

[0002]

2. Description of the Related Art An amorphous semiconductor thin film formed by glow discharge decomposition of a raw material gas or photo-CVD can be formed by a vapor phase growth method, so that it is easy to increase the area and the formation temperature is low. It has a feature that it can be formed on a substrate having flexibility such as resin. A solar cell module using such an amorphous thin film is a sub-module of an amorphous solar cell that is electrically connected in series or in parallel, and is made of a weather resistant material such as glass that does not deteriorate the solar cell outdoors and does not allow moisture to pass. It is sandwiched between the protective substrates and the solar cell is sealed with an adhesive resin such as ethylene vinyl acetate (EVA).

[0003]

As a method of connecting solar cells in series or in parallel to manufacture a module, it is conventional to use a conductive film.
That is, the solder is fused to the solar cell electrode portion, a conductive film is further placed thereon, and the solder and the conductive film are thermally fused. Thereby, the conductive film and the solar cell electrode portion were electrically connected. However, with this method, it was difficult to modularize a thin film solar cell having a small electrode area and a large effective area, or a thin film solar cell using a synthetic resin substrate having a low melting point.

An object of the present invention is to solve the above problems and to fabricate a thin film solar cell having a small electrode area and a large effective area, and a thin film solar cell using a substrate having a low melting point, which are connected to each other. An object of the present invention is to provide a method of manufacturing a thin film solar cell module that can be used.

[0005]

In order to achieve the above object, the first method of manufacturing a thin film solar cell module of the present invention is to provide a solar cell structure having strip-shaped extraction electrodes on both ends on an insulating substrate. Place a plurality of sub-modules that are adjacent to each other on the side where the extraction electrodes are not provided, and place them on a single protective substrate with an adhesive resin layer between them. Having an adhesive resin film containing dispersed metal pieces whose both end surfaces are exposed, and a conductive film having both ends protruding from above the end submodule,
Adhesive resin films that do not contain metal pieces are laminated on parts other than the extraction electrodes, and another protective substrate is placed on top of them, and the two sides of the solar cell submodule are bonded to the protective substrate by thermocompression bonding. In addition, the extraction electrode is electrically connected to the conductive film. The metal piece is preferably a columnar body made of copper or gold-plated metal powder.

The second method of manufacturing the thin-film solar cell module of the present invention is to form a conductive protrusion on the extraction electrode of a submodule having a solar cell structure having strip-shaped extraction electrodes on both ends on an insulating substrate. , Multiple sub-modules are placed adjacent to each other on the side where the extraction electrodes are not provided, and placed on one protective substrate via an adhesive resin layer, and each module is covered with an adhesive resin film and placed on both extraction electrodes. Place a conductive film with both ends protruding above the sub-module, then place another protective substrate on the exposed surface of the conductive film and the adhesive resin film, and heat and pressure bond both sides of the solar cell module to the protective substrate. And the extraction electrode is electrically connected to the conductive film through the conductive protrusion that penetrates the adhesive resin film. Thirdly, a plurality of sub-modules having a solar cell structure having strip-shaped extraction electrodes at both ends on an insulating substrate are taken out and adjacent to each other on the side where the extraction electrodes are not provided, and an adhesive resin layer is formed on one protective substrate. And then each module is covered with an adhesive resin film, and a conductive film with a protrusion formed on one surface is placed on both extraction electrodes facing the extraction electrode. Place another protective substrate on the exposed surface of the film, and bond both sides of the solar cell module to the protective substrate by heating and pressure bonding, and connect the extraction electrode to the conductive film through the conductive protrusion that pierces the adhesive resin film. It shall be electrically connected. The conductive protrusions are preferably made of solder. In either method, it is effective that the adhesive resin is ethylene vinyl acetate.

[0007]

When the thin-film solar cell submodule is bonded to the protective substrates on both sides with the adhesive resin, the conductive film, the submodule, and the end electrodes are used to connect the submodules to each other and take out the generated power to the outside. The spaces are electrically connected to each other by conductive projections formed on the metal pieces or the end electrodes included in the adhesive resin or on the conductive film and penetrating the adhesive resin film. This avoids soldering to the conductive film.

[0008]

Embodiments of the present invention will now be described with reference to the drawings. In the embodiment shown in FIGS. 1 (a) and 1 (b), a metal piece is contained in the adhesive resin between the thin film solar cell and the weather resistant substrate.
A flexible polyethylene naphthalate film having a thickness of 50 μm was used as the substrate 1 of the solar cell. An ITO film having a thickness of 1000 Å was formed on the surface of this substrate by a sputtering method, and this ITO film was separated into strips by a laser scribing method. After that, an amorphous silicon (hereinafter referred to as a-Si) film was formed by the plasma CVD method, and this was again separated into strips by the laser scribing method. Further, silver was formed thereon to a thickness of 2000 Å by a sputtering method and separated into strips by a laser scribing method, whereby an a-Si solar cell submodule 2 was produced. Then, the substrate 1 on which the a-Si solar cell sub-module 2 was mounted was placed on the glass plate 31 which was a transparent weather-resistant protective substrate via the EVA4 film which was an adhesive resin. Then, on the electrode portion of each sub-module, a film of EVA4 containing a copper piece as the metal piece 5, for example, Hitachi Chemical
(Trade name) Anisotropic conductive film Anisolm and conductive film 6 with conductive adhesive applied to one side of the copper foil of the same width as the transparent electrode part, and the other part is a film of EVA4 only. A glass plate 32 was further placed on the above and thermocompression bonded. EVA that is an adhesive resin due to the heat of thermocompression bonding
4 melted, a-Si solar cell sub-module 2 and glass plate
31 and 32 adhere. At the same time, the extraction electrode of the a-Si solar cell sub-module 2 and the conductive film 6 are electrically connected via the copper piece 5, and the a-Si solar cell sub-modules 2 are connected to each other, and the ends are also connected. It is possible to take out the generated power from the unit 61 to the outside. Thus, a-Si
The output of the solar cell sub-module 2 is taken out to the outside by connecting the take-out electrode of each sub-module to the conductive film 6 via the copper piece 5 dispersed in the EVA 4. The submodules are connected in series and in parallel according to the required voltage. Here, the copper pieces 5 dispersed in the EVA 4 are columnar with a diameter of 50 μm and a height of 100 μm and are randomly dispersed at a pitch of about 50 μm. However, copper pieces having a spherical shape or a rivet shape are also available. It has the same effect. In order to prevent short circuit between the a-Si solar cells by the copper piece 5, the width of the EVA film 6 containing the copper piece 5 may be slightly narrower than the patterning width of the silver electrode which is the back surface electrode of the submodule 2. is important. The material of the metal piece 5 to be dispersed in the EVA 4 is not limited to copper, and may be any material as long as it makes good connection with the extraction electrode of the solar cell submodule 2 and the conductive film 6.
For example, a metal powder whose surface is coated with gold is also effective. In addition, the film thickness of the EVA4 film containing the metal powder is such that the metal powder is exposed from the EVA film and the extraction electrode of the solar cell sub-module 2 and the conductive film 6 are formed.
Should be thin enough to make good contact with. Therefore, in this trial production, the film thickness of EVA4 film was 100
μm. In addition, in this embodiment, the conductive film 6 coated with a conductive adhesive on one side is used. This is achieved by fixing the conductive film 6 to the EVA 4 film or the glass plate 32 with the conductive adhesive. This is to prevent the conductive film 6 from being displaced during thermocompression bonding. With this structure, it is possible to easily connect the solar cell submodules 2 in series or in parallel with each other and take out the electric power to the outside without soldering to the extraction electrodes of the solar cell submodules 2. Also, by making the width of the conductive film 6 smaller than the back electrode width of the solar cell sub-module 2, it is not necessary to perform precise alignment, so that an a-Si solar cell module having a small extraction electrode area and high area efficiency is produced. There are things you can do.

As a structure having the same effect, there is a structure shown in FIGS. 2 (a) and 2 (b) according to another embodiment of the present invention. In this example, a flexible polyretylene naphthalate film having a film thickness of 50 μm was used as the substrate 1. An ITO film is formed on this substrate by a sputtering method to a thickness of 1000 Å, and this IT
The O film was separated into strips by the laser scribing method. After that, an a-Si film is formed by the plasma CVD method,
This was again separated into strips by the laser scribing method. Further, silver was formed thereon to a thickness of 2000 Å by a sputtering method and separated into strips by a laser scribing method to form a back electrode, thereby forming an a-Si solar cell submodule 2. Here, the conductive protrusion 7 is formed by ultrasonic soldering on the electrode extraction portion of the silver electrode which is the back surface electrode.
Was formed. This conductive protrusion can be similarly formed by a method of screen-printing a conductive paste or a method of dropping solder or a conductive paste with a dispenser. Then, the solar cell sub-module 2 thus processed was placed on the glass plate 31 which is a transparent weatherproof protective substrate via the EVA 4 which is an adhesive resin. A film of EVA 4, a conductive film 6 in which a conductive adhesive was applied to one surface of a copper foil, and a glass plate 32 were placed thereon and thermocompression bonded. EVA 4 which is an adhesive resin is melted by the heat generated by thermocompression bonding, and the solar cell submodule 2 and the glass plates 31 and 32 are adhered to each other. This time,
Since the conductive protrusion 7 formed on the silver electrode portion of the solar cell sub-module 2 breaks through the EVA 4 film on it and is electrically connected to the conductive film 6 thereon, the solar cell sub-module 2 It is used to take out the generated power to the outside by connecting between. What is important in this structure is to sharpen the tips of the conductive protrusions 7 so that the EVA 4 film can be pierced. In this example, soldering was performed so that the solder had a conical shape. Further, by applying the low melting point solder to the conductive protrusions 52 and the conductive film 6, the low melting point solder is melted during thermocompression bonding, and the conductive protrusions 7 and the conductive film 6 are soldered.

FIG. 3 shows a thin film solar cell module manufactured according to another embodiment of the present invention, in which conductive protrusions are formed on a conductive film 6 for connecting thin film solar cell submodules in series or in parallel. . In this case, a flexible polyethylene naphthalate film having a thickness of 50 μm was used for the substrate 1 of the solar cell. An ITO film is formed on this substrate by a sputtering method to a thickness of 1000 Å.
The film was separated into strips by the laser scribing method. After that, an a-Si film was formed by the plasma CVD method, and this was again separated into strips by the laser scribing method.
Further, silver was formed thereon to a thickness of 2000 Å by a sputtering method and separated into strips by a laser scribing method, whereby an a-Si solar cell submodule 2 was produced. Then, the solar cell sub-module 2 is provided with a glass plate 31 which is a transparent weatherproof protective substrate and an EVA which is an adhesive resin.
Placed on top of 4. A film of EVA 4 and a conductive film 6 having conductive projections 7 were placed thereon, with the projections 7 on the lower side, and a glass plate 32 was further placed thereon, followed by thermocompression bonding. As a method for attaching the conductive protrusions 7 to the conductive film 6, a method shown in FIG.
Similar to the embodiment shown in the above, the method can be performed by ultrasonic soldering, a method of screen-printing a conductive paste, or a method of dropping solder or a conductive paste with a dispenser. EVA 4 which is an adhesive resin is melted by the heat generated by thermocompression bonding, and the solar cell submodule 2 and the glass plates 31 and 32 are adhered to each other. At this time, the conductive protrusions 7 formed on the lower surface of the conductive film 6 pierce the EVA 4 film as the base and electrically connect to the extraction electrodes of the solar cell sub-module 2, so that the a-Si solar cell modules 2 are connected to each other. It is also used for connecting the power supply and taking out the generated power to the outside. What is important in this structure is to make the tips of the conductive protrusions 7 sharp so that they can break through the EVA 4 film. In this example, the soldering was performed so that the solder had a conical shape. Further, a method of applying the low melting point solder to the conductive protrusions to melt the low melting point solder during thermocompression bonding and soldering the conductive protrusions 7 and the conductive film 6 is also effective.

[0011]

According to the present invention, the conductive film and the end electrode are attached by pressure welding of the metal piece contained in the adhesive resin film or the end electrode of the solar cell sub-module or the conductive protrusion formed on the conductive film. By electrically connecting, there is an advantage that a soldering process is not required and a thin electrode solar cell using a small electrode area or a synthetic resin substrate can be connected. By using this method, the generated power per unit area of the thin film solar cell module can be easily increased. Moreover, since a complicated wiring process is not required, the manufacturing cost of the thin film solar cell module can be reduced.

[Brief description of drawings]

FIG. 1 shows a thin-film solar cell module according to an embodiment of the present invention, (a) is a sectional view and (b) is a plan view.

FIG. 2 shows a thin-film solar cell module according to an embodiment of the second invention, (a) is a sectional view and (b) is a plan view.

FIG. 3 shows a thin-film solar cell module according to an embodiment of the third invention, (a) is a cross-sectional view and (b) is a plan view.

[Explanation of symbols]

 1 solar cell substrate 2 solar cell sub-modules 31, 32 glass plate 4 EVA 5 copper piece 6 conductive film 7 conductive protrusion

Claims (7)

[Claims] 1. An adhesive resin layer on a protective substrate, wherein a plurality of sub-modules having a solar cell structure having strip-shaped extraction electrodes at both ends on an insulating substrate are adjacent to each other on the side where the extraction electrodes are not provided. On top of both extraction electrodes on the top surface, and an adhesive resin film that has a width that is slightly narrower than that width and that contains metal pieces with exposed end surfaces, and a sub-module whose both ends are ends. The conductive film that protrudes further is laminated on an adhesive resin film that does not contain metal pieces on the part other than the extraction electrode, and then another protective substrate is placed on them, and by thermocompression bonding, the solar cell sub A method for manufacturing a thin-film solar cell module, characterized in that both sides of the module are adhered to a protective substrate and the extraction electrode is electrically connected to a conductive film. 2. The metal piece is a columnar body made of copper.
A method for manufacturing the thin film solar cell module described. 3. The method of manufacturing a thin film solar cell module according to claim 1, wherein the metal piece is made of gold-plated metal powder. 4. An electrically conductive protrusion is formed on an extraction electrode of a submodule having a solar cell structure having strip-shaped extraction electrodes at both ends on an insulating substrate, and a plurality of extraction electrodes of the submodule are provided. Adjacent to the other side, it is placed on one protective substrate via an adhesive resin layer, each module is covered with an adhesive resin film, and both ends of both extraction electrodes project above the submodule. On the exposed surface of the conductive film and the adhesive resin film, and by thermocompression bonding, both sides of the solar cell module are bonded to the protective substrate, and the extraction electrode pierces the adhesive resin film. A method for manufacturing a thin-film solar cell module, which comprises electrically connecting to a conductive film via a conductive protrusion. 5. An adhesive resin layer on one protective substrate, wherein a plurality of sub-modules having a solar cell structure having strip-shaped extraction electrodes at both ends on an insulating substrate are adjacent to each other on the side where the extraction electrodes are not provided. The module, cover each module with an adhesive resin film, and place a conductive film with a protrusion on one side of both extraction electrodes facing the extraction electrode. Put another protective substrate on the exposed surface of the resin film, and bond both sides of the solar cell module to the protective substrate by heating and pressure bonding, and at the same time, take out the electrode from the conductive resin through the conductive protrusion that penetrates the adhesive resin film. And a method for manufacturing a thin-film solar cell module, which is characterized in that the thin-film solar cell module is electrically connected to. 6. The method for manufacturing a thin-film solar cell module according to claim 4, wherein the conductive protrusion is made of solder. 7. The method for manufacturing a thin-film solar cell module according to claim 1, wherein the adhesive resin is ethylene vinyl acetate.