JP4061525B2 - Manufacturing method of solar cell module - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a solar cell module.
[0002]
[Prior art]
Currently, clean energy research and development is underway from the standpoint of environmental protection. Among them, solar cells are attracting attention because their resources (sunlight) are infinite and pollution-free. A typical example of a photoelectric conversion device in which a plurality of solar cell elements formed on the same substrate are connected in series is a thin film solar cell.
[0003]
Thin-film solar cells are expected to become the mainstream of solar cells in the future because they are thin and lightweight, inexpensive to manufacture, and easy to increase in area, and are attached to roofs and windows of buildings in addition to power supply. Demand is also expanding for commercial and general residential use.
[0004]
Conventional thin-film solar cells have used glass substrates, but research and development of flexible solar cells using plastic films are being promoted in terms of weight reduction, workability, and mass productivity. Furthermore, the thing using the film substrate which carried out the insulation coating to the flexible metal material is also developed. Taking advantage of this flexibility, mass production became possible by a roll-to-roll method or a stepping roll method.
[0005]
The above thin film solar cell is a photoelectric conversion element (or cell) in which a first electrode layer made of a metal electrode layer, a photoelectric conversion layer made of a thin film semiconductor layer, and a transparent electrode layer are laminated on a flexible electrically insulating film substrate. A plurality of are formed. Necessary for the first electrode layer of the first photoelectric conversion element and the transparent electrode layer of the last photoelectric conversion element by repeating the electrical connection between the first electrode layer of a certain photoelectric conversion element and the adjacent transparent electrode layer A large voltage can be output. For example, in order to obtain an alternating current of 100 V as a commercial power source by alternating current with an inverter, the output voltage of the thin-film solar cell is desirably 100 V or higher, and actually several tens or more elements are connected in series.
[0006]
Such a photoelectric conversion element and its series connection are formed by forming an electrode layer and a photoelectric conversion layer, patterning each layer, and a combination procedure thereof. An example of the configuration and manufacturing method of the solar cell is described in, for example, Japanese Patent Application Laid-Open No. 10-233517 and Japanese Patent Application No. 11-19306.
[0007]
FIG. 3 shows a simplified perspective view of the structure of the thin-film solar cell described in the above publication. In FIG. 3, the unit photoelectric conversion element 62 formed on the surface of the substrate 61 and the connection electrode layer (metal electrode layer) 63 formed on the back surface of the substrate 61 are completely separated into a plurality of unit units, respectively. It is formed by shifting. For this reason, the current generated in the photoelectric conversion layer 65, which is an amorphous semiconductor portion of the element 62, is first collected in the transparent electrode layer 66, and then on the back surface through the current collecting holes 67 formed in the transparent electrode layer region. It leads to the connection electrode layer 63, and further to the outside of the transparent electrode layer region of the element adjacent to the element through the connection hole 68 for series connection formed outside the transparent electrode layer region of the element in the connection electrode layer region. The extended lower electrode layer 64 is reached, and both elements are connected in series.
[0008]
FIG. 4 shows a series-connected thin film solar cell of a type using a conventional glass substrate different from the above, FIG. 4 (a) is a plan view of the thin film solar cell surface on the non-light-receiving surface side, and FIG. The figure is shown.
[0009]
On the glass substrate 1, transparent electrode layers u1, u2, u3..., Photoelectric conversion layers s1, s2, s3... And metal electrode layers e1, e2, e3. ing. The outline of the manufacturing method will be described below.
[0010]
First, the transparent electrode layer u is formed on the substrate 1 by a thermal CVD method, and patterned into a predetermined number of divisions using a laser processing method. At the same time, the thin film solar cell and its periphery are also electrically separated.
[0011]
Next, a photovoltaic layer s made of a-Si is formed using a plasma CVD method, and laser processing is performed in parallel to the patterning line of the transparent electrode layer u in a direction orthogonal to the serial direction of the thin film solar cell. .
[0012]
Next, the metal electrode layer e is formed by sputtering, laser processing is performed in parallel with the patterning line of the photoelectric conversion layer s, and the thin-film solar cell and its peripheral edge are electrically separated.
[0013]
As a result of the above steps, the transparent electrode layer u1, the photoelectric conversion layer s1, the metal electrode layer e1-the transparent electrode layer u2, the photoelectric conversion layer s2, the metal electrode layer e2-the transparent electrode layer u3, the photoelectric conversion layer s3, the metal electrode layer e3. The series connection of the thin film solar cell elements (unit cells) in this order is completed.
[0014]
A plurality of unit cells connected in series as described above are further formed into a panel shape to form a thin-film solar cell module, which is installed on a roof or wall of a building or a stand provided on the ground.
[0015]
As the thin film solar cell module, in order to seal a solar cell formed on an electrically insulating film substrate with an electrically insulating protective material, both the light receiving surface side and the non-light receiving surface side of the solar cell are used. There are known those provided with a protective layer.
[0016]
FIG. 5 shows an example of a schematic structure of a conventional solar cell module.
[0017]
In FIG. 5, a solar cell 21 has a plurality of solar cell elements connected in series or in parallel, a surface protection member 22 such as a glass plate (for example, a thickness of 3 mm) on the light receiving surface side, and a non-light receiving surface side. EVA (ethylene-vinyl acetate copolymer resin) which is provided with a back surface protection member 30 made of an aluminum foil obtained by adhering ethylene monofluoride (trade name: Tedlar, manufactured by DuPont) on both sides and has excellent adhesive sealing properties and is inexpensive. ) Or the like. As the EVA, for example, a sheet-like EVA having a thickness of 0.4 to 0.8 mm is used. This EVA is formed by laminating each of the above members, and using a vacuum laminator, heating and pressurizing at a temperature of about 120 ° C. to 160 ° C., performing adhesive fixation, and then in a dryer at 130 ° C. to 160 ° C. Heat cured. EVA that protrudes around the glass plate is removed by cutting.
[0018]
Also, the solar cell 21 has internal lead wires 50 and 60 electrically connected to the positive (+) and negative (−) electrodes, and the internal lead wires 50 and 60 are bonded and fixed to the back surface protection member 30. The connection terminal box 70 is guided through the back surface protection member 30 and is electrically connected to the core wires 90 and 100 of the cable 80 as an external lead wire inside the connection terminal box 70. Forming.
[0019]
The surface protection member 22 may be made of an organic material such as a transparent acrylic plate in addition to an inorganic material such as a glass plate. In addition to the above, the back surface protection member 30 may be a single organic film such as a fluorine film, a composite material obtained by bonding an organic film and a metal foil, or a metal / inorganic material such as a metal plate or a glass plate. Sometimes used.
[0020]
FIG. 2 schematically shows an example of the configuration of a module using the thin-film solar cell shown in FIG. In FIG. 2, for convenience of explanation of the present invention, some members are omitted. 2, 2 is tempered glass as a translucent protective member, 3a and 3b are EVA as an adhesive, 4 is a thin film solar cell, 4a is a metal electrode layer in the thin film solar cell, and the metal electrode layer in FIG. It corresponds to e. Other layers in the thin film solar cell are omitted.
[0021]
In FIG. 2, 5 is, for example, an aluminum foil as a conductive film in the back surface protection member, and 6a is, for example, ethylene monofluoride as an electrically insulating film. One of the electrically insulating films is omitted. 7 is a conductive tape, one end of which is connected to two extraction electrodes in the thin-film solar cell, and the other end is pulled out from a hole formed in the back surface protection member and fixed in the back surface protection member. Connected to external terminal.
[0022]
[Problems to be solved by the invention]
However, the conventional method for manufacturing a solar cell module has the following problems.
[0023]
In the process of forming a thin film solar cell, pinholes are generated by dust or the like adhering to the substrate, and the lower electrode layer (64 in FIG. 3) or the metal electrode layer (e in FIG. 4) and the transparent electrode layer This causes a problem of short circuiting. The reason is presumed that the transparent electrode is also formed in the pinhole at the time of forming the transparent electrode layer. Usually, the local short-circuited portion by this pinhole is several volts to the unit cell. These can be electrically separated by applying a reverse bias voltage. The reason is presumed to be that the transparent electrode in the pinhole is incinerated and removed by the generation of Joule heat due to the reverse bias voltage application process.
[0024]
The local short-circuit portion due to the pinhole can be removed by a reverse bias voltage application process before the modularization process, but a local short-circuit may occur in the modularization process. The cause is as follows.
[0025]
Since the connection electrode layer and the metal electrode layer have large ductility and the patterning width (insulation width) is narrow (about 0.4 mm), the electrode layer crosses the insulation groove when scratches occur during the modularization process. May be connected. In the modularization process, since the resin is sealed by applying pressure, it is estimated that the thin film layer is rubbed and damaged at that time. Furthermore, in the case of the thin film solar cell as shown in FIG. 3, the solar cell is formed on a flexible polymer substrate. However, the thin film itself constituting the solar cell is not as strong as bending as the substrate, and when the curvature exceeds a certain level, The transparent electrode layer and the connection electrode layer may be short-circuited. Such a microcrack is an irreversible steady leak unlike the short circuit between the connection electrode layer and the metal electrode layer.
[0026]
By the way, in the thin film solar cell module described above, in the modularization process, after the metal electrode layer or connection electrode layer of the thin film solar cell is covered with the back surface protection member, each solar cell element is covered with an insulating layer. Therefore, a reverse bias voltage cannot be applied. Therefore, there is a problem that the improvement process by applying the reverse bias cannot be performed when the short circuit of the cell based on the pinhole occurs during the modularization process or immediately before the completion of the module.
[0027]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a solar cell that can be improved by applying a reverse bias to each solar cell element even immediately before the completion of the module. It is to provide a method for manufacturing a module.
[0028]
[Means for Solving the Problems]
In order to solve the above-described problem, in the present invention, a solar cell in which a plurality of solar cell elements are connected in series or in parallel between a translucent surface protection member and a back surface protection member is used as an adhesive resin sealing material. In the manufacturing method of the solar cell module formed by sealing,
The back surface protection member is composed of a sheet obtained by bonding an electrically insulating film to both surfaces of a conductive film, and the conductive film is electrically separated corresponding to the metal electrode layers of the plurality of solar cell elements, And the electrical insulating films on both sides have a plurality of holes corresponding to the central part of the separated conductive film,
The solar cell of the separated conductive film is sealed by the adhesive resin sealing material in a state where the metal electrode layer of the solar cell element and the separated conductive film are electrically connected. Create a sub-module with each center on the back side of the battery module exposed,
A reverse bias is applied to the plurality of solar cell elements in the submodule through the exposed portions between adjacent conductive films, and after the reverse bias is applied, the exposed portions are filled with resin. Alternatively, a solar cell module is obtained by bonding (invention of claim 1).
[0029]
According to the above manufacturing method, the conductive film is divided into the same number as the number of unit cells, and the conductive film is electrically connected to the metal electrode layer of each unit cell constituting the thin film solar cell submodule. It becomes possible to improve by reverse bias immediately before the completion of the module.
[0030]
As an embodiment of the invention of claim 1, the inventions of claims 2 to 5 below are preferable. That is, in the manufacturing method according to claim 1, solder is applied to a surface of the exposed portion of the conductive film facing the solar cell element, and the metal electrode layer of the solar cell element and the separated conductive film are formed. Are connected by soldering (invention of claim 2). Furthermore, in the manufacturing method of Claim 1 or 2, the said electroconductive film shall form an electroconductive film, such as silver, copper, nickel, on the aluminum substrate (invention of Claim 3). This facilitates electrical connection between the conductive film and the metal electrode layer of each unit cell.
[0031]
Furthermore, in the manufacturing method according to any one of claims 1 to 3, the outer peripheral portion of the separated conductive film surface is an electrically insulating surface by anodizing or forming an insulating layer. Invention of 4). Thereby, the electrical separation state of the conductive film is ensured, and the corrosion resistance during outdoor use can be secured.
[0032]
Further, from the viewpoint of preventing damage to each unit cell, the invention of claim 5 is preferable as will be described in detail later. That is, in the manufacturing method according to claim 1, electrical connection between the metal electrode layer of the solar cell element and the separated conductive film is performed in a non-power generation region of the solar cell element. .
[0033]
DETAILED DESCRIPTION OF THE INVENTION
Based on FIG. 1, the Example of the manufacturing method of a solar cell module is described below.
1A is a schematic plan view of the sub-module stage in the solar cell module, FIG. 1B is a schematic side sectional view taken along line AA of FIG. 1A, FIG. FIG. 1D shows a schematic plan view and a side sectional view of an intermediate stage before the submodule is formed.
[0034]
First, as shown in FIGS. 1C and 1D, an EVA film 3a having a thickness of 0.4 mm is placed as an adhesive on a tempered glass 2 having a thickness of 2 mm, and a thin-film solar cell 4 is placed. The glass substrate of the thin film solar cell 4 is on the EVA film 3a side, and the metal electrode layer 4a is on the opposite side. In addition, the dimension of the tempered glass 2 is desirably larger than that of the thin film solar cell 4, and the EVA film 3 a as an adhesive is desirably smaller than the tempered glass 2 and larger than the thin film solar cell 4.
[0035]
Here, the extraction electrode of the thin film solar cell 4 is indicated by plus (+) and minus (−), respectively, in FIG.
[0036]
Next, FIG. 1 (a) and FIG. 1 (b) show a state after submodule formation, and the subsequent steps will be described below with reference to this figure. An EVA film 3b having a thickness of 0.4 mm and a back surface protective member having a thickness of 0.3 mm are placed as adhesives on the upper part of the thin film solar cell module at the stage shown in FIGS. 1C and 1D. Here, the back surface protection member is made of the aluminum film 5 in which the above-mentioned ethylene monofluoride films 6a and 6b are bonded to both surfaces. The thicknesses of ethylene monofluoride 6a, 6b and aluminum film 5 are each 0.1 mm.
[0037]
Here, the aluminum film 5 is electrically divided by the same number as the number of elements of the thin film solar cell 4. Further, the aluminum film surface is electrically insulated from the end to 10 mm by anodizing. This is to ensure corrosion resistance when used outdoors.
[0038]
The EVA film 3b and the back surface protection member made of the ethylene monofluoride films 6a and 6b and the aluminum film 5 are weakly bonded by pressing at a low temperature of about 80 ° C. The EVA film 3b and the two ethylene monofluoride films 6a and 6b are perforated so that the front and back aluminum films 5 at the same location are exposed.
[0039]
Solder 8 is applied to the surface of the aluminum film 5, and when the thin film solar cell 4 is placed, each aluminum film exposure position is positioned at the center of the metal electrode layer 4 a of each thin film solar cell 4. Set to.
[0040]
Thereafter, after temporarily bonding at a low temperature of 80 ° C., the heat is locally applied to the exposed portion of the aluminum film with a soldering iron to melt the solder 8, and the metal electrode layer 4 a of the thin film solar cell 4 and the aluminum film 5 are electrically connected. Connect to.
[0041]
Finally, by pressing at a temperature of 150 ° C., the EVA films 3a and 3b of the adhesive are cross-linked, resin-sealed, and the submodule is finished. FIGS. 1A and 1B schematically show a state where the sub-modularization is completed.
[0042]
In the thin-film solar cell submodule manufactured as described above, since the metal electrode layer 4a of each unit cell is connected to the aluminum film 5, the unit cell can be improved by applying a reverse bias after modularization. It becomes.
[0043]
The exposed portion 5a of the aluminum film 5 of the thin film solar cell submodule shown in FIG. 1 is provided in the non-power generation region at the lower end portion of the metal electrode layer 4a, as shown in FIG. The exposed portion is electrically insulated by filling or bonding with a resin after applying a reverse bias, thereby completing a thin-film solar cell module.
[0044]
【The invention's effect】
According to this invention, as described above, a solar cell in which a plurality of solar cell elements are connected in series or in parallel between the translucent surface protection member and the back surface protection member is sealed with the adhesive resin sealing material. In the manufacturing method of the solar cell module which stops,
The back surface protection member is composed of a sheet obtained by bonding an electrically insulating film to both surfaces of a conductive film, and the conductive film is electrically separated corresponding to the metal electrode layers of the plurality of solar cell elements, And the electrical insulating films on both sides have a plurality of holes corresponding to the central part of the separated conductive film,
The solar cell of the separated conductive film is sealed by the adhesive resin sealing material in a state where the metal electrode layer of the solar cell element and the separated conductive film are electrically connected. Create a sub-module with each center on the back side of the battery module exposed,
A reverse bias is applied to the plurality of solar cell elements in the submodule through the exposed portions between adjacent conductive films, and after the reverse bias is applied, the exposed portions are filled with resin. Or since it was decided to become a solar cell module by bonding,
Immediately before completion of the module, it is possible to provide a method for manufacturing a solar cell module that can be improved by applying a reverse bias to each solar cell element.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a submodule for explaining a manufacturing process according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing a simplified configuration of a conventional solar cell module. FIG. 4 is a perspective view showing a simplified example of the configuration of FIG. 4. FIG. 5 is a diagram showing a configuration example of a thin film solar cell different from FIG. 3. FIG. 5 is a diagram showing an example of a schematic structure of a conventional solar cell module. Explanation】
2: tempered glass, 3a, 3b: EVA film, 4: thin film solar cell, 4a: metal electrode layer, 5: aluminum film, 5a: exposed portion, 6a, 6b: ethylene monofluoride film, 8: solder, 22: Surface protective member, 30: back surface protective member, 40: adhesive resin sealing material.

Claims (5)

In a method for manufacturing a solar cell module, in which a solar cell in which a plurality of solar cell elements are connected in series or in parallel is sealed with an adhesive resin sealing material between a translucent surface protective member and a back surface protective member. ,
The back surface protection member is composed of a sheet obtained by bonding an electrically insulating film on both surfaces of a conductive film, and the conductive film is electrically separated corresponding to the metal electrode layers of the plurality of solar cell elements, And the electrical insulating films on both sides have a plurality of holes corresponding to the central part of the separated conductive film,
The solar cell of the separated conductive film is sealed by the adhesive resin sealing material in a state where the metal electrode layer of the solar cell element and the separated conductive film are electrically connected. Create a sub-module with each center on the back side of the battery module exposed,
A reverse bias is applied to the plurality of solar cell elements in the submodule through the exposed portions between adjacent conductive films, and after the reverse bias is applied, the exposed portions are filled with resin. Alternatively, a method for producing a solar cell module, wherein the solar cell module is formed by bonding. The manufacturing method according to claim 1, wherein solder is applied to a surface of the exposed portion of the conductive film facing the solar cell element, and the metal electrode layer of the solar cell element and the separated conductive film are soldered. A method for manufacturing a solar cell module, wherein the solar cell module is connected by attaching. 3. The method of manufacturing a solar cell module according to claim 1, wherein the conductive film is formed by forming a conductive film such as silver, copper, or nickel on an aluminum substrate. 4. The manufacturing method according to claim 1, wherein an outer peripheral portion of the separated conductive film surface is an electrically insulating surface by anodizing or forming an insulating layer. Manufacturing method of battery module. 5. The manufacturing method according to claim 1, wherein electrical connection between the metal electrode layer of the solar cell element and the separated conductive film is performed in a non-power generation region of the solar cell element. A method for producing a solar cell module.

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