JP3448924B2 - Method for manufacturing thin-film solar cell module - Google Patents

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 made of a weather-resistant material such as glass that electrically connects sub-modules of an amorphous solar cell in series or in parallel and does not allow the solar cell to deteriorate outdoors and prevent moisture from passing. 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 reference means of the method for producing a thin film solar cell module of the present invention is 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 protruding from above the sub module whose both ends are ends, and not including metal pieces other than above the extraction electrode. Adhesive resin films are laminated, another protective substrate is placed on them, and both sides of the solar cell submodule are bonded to the protective substrate by heating and pressure bonding, and the extraction electrode is made of a conductive film. It shall be electrically connected to each other. The metal piece is preferably a columnar body made of copper or gold-plated metal powder.

According to the method of manufacturing a thin film solar cell module of the present invention, a conductive protrusion is formed on the extraction electrode of a sub module having a solar cell structure having strip-shaped extraction electrodes on both ends on an insulating substrate, Plural 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. Place the protruding conductive film on the sub module,
Furthermore, another protective substrate is placed on the exposed surface of the conductive film and the adhesive resin film, and both sides of the solar cell module are adhered to the protective substrate by thermocompression bonding, and the extraction electrode is electrically conductive through the adhesive resin film. It shall be electrically connected to the conductive film through the protrusion. Another aspect of the present invention is that 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 a plurality of sub-modules are adjacent to each other on the side where the extraction electrodes are not provided, and an adhesive resin is formed on one protective substrate. The module is covered with a layer, each module is covered with an adhesive resin film, and a conductive film having protrusions formed on one surface is placed on both extraction electrodes so as to face the extraction electrodes and the conductive film and Place another protective substrate on the exposed surface of the adhesive resin film and bond it to both sides of the solar cell module by heating and pressure bonding, and at the same time make the extraction electrode conductive through the conductive protrusion that pierces the adhesive resin film. It shall be electrically connected to the film. 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]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, reference examples and embodiments of the present invention will be described with reference to the drawings. In the reference example 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. Flexible film thickness 50μ on the substrate 1 of the solar cell
m polyethylene naphthalate film was used. 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. And a glass plate which is a transparent weatherproof protective substrate
31 via EVA4 film which is an adhesive resin
The substrate 1 on which the -Si solar cell submodule 2 was mounted was placed. An EVA4 film containing a copper piece as the metal piece 5, for example, an anisotropic conductive film Anisolm under the trade name of Hitachi Chemical Co., Ltd. and a copper foil having the same width as the transparent electrode section is formed on the electrode section of each sub-module. Conductive film 6 coated with a conductive adhesive on one side, EVA4 on the other parts
The chisel film was placed, and the glass plate 32 was further placed thereon and thermocompression bonded. EVA 4 which is an adhesive resin is melted by the heat generated by thermocompression bonding, and the a-Si solar cell submodule 2 and the glass plates 31 and 32 are adhered to each other. At the same time, through the copper piece 5,
The extraction electrode of the a-Si solar cell sub-module 2 and the conductive film 6 are electrically connected, the a-Si solar cell sub-modules 2 are connected to each other, and the generated power from the end 61 to the outside is connected. It can be taken out. In this way, the output of the a-Si solar cell submodule 2 is extracted to the outside by connecting the extraction electrode of each submodule to the conductive film 6 through the copper piece 5 dispersed in the EVA 4. There is. The submodules are connected in series and in parallel according to the required voltage. EVA4
Here, the copper pieces 5 dispersed in the
It is a column of 100 μm and randomly dispersed at a pitch of about 50 μm, but a copper piece having a spherical shape or a rivet shape also 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. E
The material of the metal piece 5 to be dispersed in the VA 4 is not limited to copper and may be any material as long as the connection between the extraction electrode of the solar cell submodule 2 and the conductive film 6 is good, for example, metal powder. It is also effective to coat the surface with gold. Further, the film thickness of the EVA4 film containing the metal powder is such that the metal powder is exposed from the EVA film,
It must be thin enough to make sufficient contact with the extraction electrode of the solar cell submodule 2 and the conductive film 6.
From this, the film thickness of the EVA4 film was set to 100 μm in this trial production. Further, in this reference example, the conductive film 6 coated with a conductive adhesive on one side was used.
This is to prevent the conductive film 6 from being displaced during thermocompression bonding by fixing it to the film or the glass plate 32. 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. Further, by making the width of the conductive film 6 smaller than the width of the back surface electrode of the solar cell sub-module 2, it is not necessary to perform precise alignment, so that the extraction electrode area is small and the area efficiency is high.
-Si solar cell module can be manufactured in some cases.

As a structure having the same effect, there is a structure shown in FIGS. 2 (a) and 2 (b) according to an 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.
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 to form a back electrode, thereby forming an a-Si solar cell submodule 2. Here, the conductive protrusion 7 was formed by ultrasonic soldering on the electrode extraction portion of the silver electrode which is the back surface electrode. 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. At this time, the conductive protrusion 7 formed on the silver electrode portion of the solar cell sub-module 2 pierces the EVA 4 film on the top,
Since it is electrically connected to the conductive film 6 thereon, the solar cell sub-modules 2 are connected to each other and used for taking out the generated power to the outside. 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, a method of applying the low melting point solder to the conductive protrusions 52 and the conductive film 6 to melt the low melting point solder during thermocompression bonding and soldering the conductive protrusions 7 and the conductive film 6 is also effective.

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 sharpen the tips of the conductive protrusions 7 so that the EVA 4 film can be pierced. In this example, the soldering was performed so that the solder had a conical shape. Further, a method of applying 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 solder is formed by electrically connecting the conductive film and the end electrode by pressure contact of the conductive electrode formed on the end electrode of the solar cell sub-module or the conductive film. No need for attachment process,
It has an advantage that a thin film 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 a reference example 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 present invention, (a) is a sectional view and (b) is a plan view.

FIG. 3 shows a thin film solar cell module according to another embodiment of the present invention, in which (a) is a sectional view and (b) is a plan view.

[Explanation of symbols]

1 solar cell substrate 2 Solar cell sub-module 31, 32 glass plate 4 EVA 5 Copper pieces 6 Conductive film 7 Conductive protrusion

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 31/00-31/12

Claims (4)

(57) [Claims] 1. A conductive protrusion is formed on a take-out electrode of a sub-module having a solar cell structure having strip-like take-out electrodes at both ends on an insulating substrate, and a plurality of the sub-modules are provided with take-out electrodes. 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. 2. 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. 3. The method for manufacturing a thin-film solar cell module according to claim 1, wherein the conductive protrusion is made of solder. 4. The method for manufacturing a thin film solar cell module according to claim 1, wherein the adhesive resin is ethylene vinyl acetate.