JPH0543307B2 - - Google Patents

Description

[Detailed description of the invention]

<Field of Application> The present invention relates to a solar cell module suitable for electric power. More specifically, the present invention relates to a solar cell module that is lightweight and has sufficient strength. <Prior art> Solar cell modules (hereinafter referred to as "modules") use tempered glass for transparent windows, various solar cells as photovoltaic elements, metal sheets as sealing materials, and these structural elements are used as fillers. Structures in which polyvinyl butyral or ethylene vinyl acetate resin is laminated together and sealed with a metal frame or plastic frame are known (for example, "Amorphous Solar Cell" co-authored by Takahashi and Konagai (published by Shokodo) 17
(See pages 18 to 18). In a module with such a structure, the weight of the module is inevitably large, and in order to install such a heavy object as a power generation unit, it is necessary to construct a structure (array) with a reliable foundation and frame. Solar power generation costs consist of the costs of peripheral materials in addition to the cost of solar cell modules, and reducing not only the module cost but also the cost of peripheral materials is essential in raising solar power generation to a practical level. be. From this point of view, aluminum honeycomb structures and paper are used as encapsulants and supports against wind pressure in order to reduce the weight of solar cell modules, reduce the burden on foundations and frames, and reduce the cost of peripheral components. Proposals have been made to reduce the weight of modules while maintaining mechanical strength by using honeycomb structures and rib structures.
International PVSEF-1) (see pages 665-668). However, even in this case, the thickness of the transparent window material is required to ensure strength against hail and wind pressure.
It is necessary to use tempered glass of 3.2 mm or more, and especially in the case of amorphous solar cells that use glass substrates, the window on the sunlight incident side is double-glazed.
There are limits to how lightweight modules can be made. In addition, such honeycomb structure and rib structure can be used as a heat insulating layer.
As a result, the surface temperature of the solar cell increases and the photoelectric conversion efficiency decreases. From this point of view, we first proposed a solar cell module in which a transparent multilayer plate with a hollow structure is laminated on the side of the photovoltaic element as a support by patent application No. 61-141421.
proposed in the specification. However, this structure has a problem in that the photoelectric conversion efficiency decreases due to a decrease in transmittance in the portion of the support overlapping the intermediate member of the transparent multilayer plate. <Object of the invention> The object of the present invention is to solve these drawbacks of the conventional technology, reduce the weight of the solar cell module, and make it possible to reduce the cost of solar power generation and expand various applications accordingly. Our goal is to provide solar cell modules. <Structure and operation of the invention> That is, the present invention has a hollow structure in which a plurality of transparent plates made of a non-metallic material are engaged with each other by an intermediate member arranged at predetermined intervals on the daylighting side of a solar power generation element. A solar cell module in which supports made of transparent multilayer plates are laminated, characterized in that the solar cell module is laminated so that the collection bus bar of the solar power generation elements and the intermediate member of the support are overlapped. It is. With this configuration, the intermediate member of the support, which causes a decrease in transmittance, overlaps the bus bar of the collecting electrode, which is the non-generating area, so that the generating area can be used effectively and more power can be obtained. become. By the way, the transparent multi-layer board used as the window material of the present invention is a hollow, lightweight transparent multi-layer board in which a plurality of transparent boards are connected at predetermined intervals via hollow members,
For example, a structure in which synthetic resin plates with high impact resistance and good workability are connected by bridging intermediate members such as ribs or corrugated plates at predetermined intervals to ensure strength and to reduce weight by creating voids between transparent plates. It is the body. The synthetic resin used for this transparent plate is not particularly limited as long as it is transparent, and all known transparent plate materials such as polycarbonate resin and acrylic resin can be used. Polycarbonate resin is excellent in terms of impact resistance and is preferred. Further, the intermediate member is not particularly limited as long as it is lightweight and strong, but it is preferably one that does not reduce the light transmittance of the multilayer board. Therefore, as the intermediate member, plate-shaped bodies, columnar bodies, framework structures of these bodies, etc. can be used, but from the viewpoint of strength and light transmission, a cell structure in which plate-shaped bodies are arranged so as to have a large number of cell chambers is preferable. Preferably applied. Examples of such a cell structure include a multi-rib structure in which transparent sheets are joined by ribs at regular intervals to have columnar cells parallel to the sheet surface. A multi-rib structure multi-layer board can be obtained by extrusion molding polycarbonate resin or the like through a die having the same rib structure as the side cross-sectional structure of the multi-rib structure. In particular, from the viewpoint of sunlight transmittance and productivity of the obtained multilayer structure, the above-mentioned multi-layer board made of a transparent synthetic resin with an integrally molded multi-rib structure with an air layer in the middle is considered to be the best choice. It can be suitably used as a window material of the invention. As a multi-layer board having such a multi-rib structure, Panlight Uni (trade name: manufactured by Teijin Kasei Ltd.) is commercially available as a light-transmitting heat insulating material. However, if such a synthetic resin has a high water vapor permeability, there will be movement of water through the plurality of sheets.
As a result, dew condensation is observed within the hollow portion, causing the transparent window to become foggy and the light transmittance to decrease. Furthermore, when the permeated moisture reaches the surface of the photovoltaic element, it promotes corrosion of the electrode surface, which is unfavorable in terms of long-term stability.
Furthermore, such a multilayer plate acts as a heat insulating layer and increases the surface temperature of the photovoltaic element, inevitably reducing the photoelectric conversion efficiency. In order to avoid such drawbacks and fully realize the advantages of the multilayer board, the present inventor made further improvements. That is, in order to reduce the water vapor permeability of the synthetic resin, the multilayer plate was provided with a moisture permeability prevention film on the surface facing the photovoltaic element. In addition, the hollow part of the multi-layer board is structured to communicate with the outside, and the hollow part is sealed while remaining open to the atmosphere, thereby reducing the heat insulating effect of the hollow part. The multi-rib structure described above with columnar cells in which the hollow portions are parallel is preferred in terms of easy ventilation. Particularly when assembling a structure using such multilayer board modules, it is preferable to arrange the columnar cells at an angle with respect to the horizontal plane. With this structure, the columnar cells exhibit a plurality of chimney effects, allowing air to flow and preventing a rise in surface temperature. Furthermore, this airflow prevented condensation of moisture that permeated the synthetic resin and entered the columnar cells. On the other hand, by providing the moisture permeability prevention film on the side of the multilayer plate facing the photovoltaic element, it is possible to prevent moisture from entering the photovoltaic element. Such moisture permeation prevention films include inorganic thin films such as amorphous silicon films and idium oxide films, and organic thin films such as polyvinylidene fluoride films, but indium oxide films are particularly preferred from the viewpoint of transparency and adhesion to adjacent layers. preferable. Further, if necessary, it is preferable to provide a transparent scratch-resistant film made of a photocurable or thermosetting resin layer on the surface of the multilayer board for the purpose of improving scratch resistance and abrasion resistance. Any known scratch-resistant film can be used as is. Furthermore, for the purpose of improving light resistance, an ultraviolet absorber may be included in these layers, or may be laminated thereunder. Next, the solar power generation element used in the present invention is not particularly limited, and known solar cells can be used as they are.
For example, silicon-based solar cells that use not only single-crystalline and polycrystalline silicon semiconductor layers but also amorphous silicon semiconductor layers as motive force layers, and so-called compound solar cells that use - group and - group semiconductor layers as electromotive force layers. can be mentioned. Among these, an integrated solar cell having a so-called integrated structure in which a plurality of solar cells formed on the same electrically insulating substrate are connected in series and parallel can be suitably used. Typical examples of such integrated solar cells are amorphous silicon solar cells and - group compound semiconductor solar cells, but among these, amorphous silicon integrated solar cells formed on a flexible electrically insulating substrate are typical examples of such integrated solar cells. Solar cells are preferable because they can take advantage of characteristics such as having a thin film structure and being lightweight, and can be continuously laminated using rolls as shown in Examples below. An integrated solar cell using such an amorphous silicon semiconductor layer as an electromotive force layer can be realized by the following method. For example, as an electrically insulating substrate, a polymer film, a ceramic plate, a glass plate, or a metal foil with an insulating layer provided on the surface can be used. In particular, a long flexible substrate that can be used for continuous film formation and dividing processing is advantageous. be. Further, for the metal electrode layer provided thereon, single metals and alloy metals such as Ti, Ag, W, Pt, Ni, Co, Cr, and nichrome can be used. Also, as a configuration of the amorphous silicon semiconductor layer of the electromotive layer, pin
In addition, there are other multilayer tandem structures such as pin/pin, pin/pin/pin, as well as narrow band gap or wide band gap amorphous structures such as amorphous silicon germanium and amorphous silicon carbide. A silicon semiconductor layer can also be used as appropriate. Further, as the transparent electrode layer, a known transparent conductive layer such as tin oxide or cadmium stannate can be used. After dividing the continuous power generation layer of the amorphous silicon solar cell having a predetermined area into cells having an appropriate area by a laser scoring method or a knife cutting method,
An integrated solar cell is obtained by electrically connecting cells. The method of electrically connecting the divided cells is not particularly limited as long as the upper electrode of one cell to be connected and the lower electrode of the other cell can be electrically connected, and the method is to connect with a lead wire. Method,
Known methods such as forming a connection layer made of a metal thin film by PVD or the like, forming a connection layer made of a conductive resin layer by screen printing, etc. can be applied. Among these, electrical connection by screen printing is preferably applied from the viewpoint of productivity and equipment. Such a method provides an integrated solar cell with a photovoltaic layer or an amorphous silicon semiconductor on a flexible polymeric film substrate. Next, as the sealing material for sealing the above-mentioned solar power generation element, as long as it can prevent the intrusion of moisture, a corrosion-proof metal sheet, an aluminum metal foil, a polyester film, a polyvinylidene fluoride film, etc. are suitable. A so-called moisture-proof film is used. Among these, a moisture-proof film made by laminating aluminum metal foil with a polyester film or the like is one of the preferred materials because it is lightweight and meets the purpose of the present invention. In addition, the filler (also referred to as "pottant") that adheres and seals the above-mentioned support, photovoltaic element, and sealing material and also serves as a cushion layer has light resistance and is compatible with each component. Polyvinyl butyral resin, ethylene vinyl acetate resin, etc., which have excellent adhesion, are used. The solar cell module of the present invention is a transparent multilayer structure, a solar power generating element, and if necessary, a sealing material is laminated with the above-mentioned filler as a glue from the sunlight incident side, and if necessary, the surrounding area is further covered with a frame. Constructed by sealing. By the way, in order to effectively collect photocurrent in solar power generation elements, as shown in Fig. 1, a busbar or finger electrode is used as a collection electrode by screen printing with Ag-based resin or vapor deposition of Ag, Al, etc.
It is formed by a method such as sputtering or adhesion of metal foil. The feature of the present invention is that the bus bar of the collector electrode and the intermediate member of the transparent multi-layer plate having a hollow structure are laminated in an overlapping manner. In the case of the above-mentioned integrated structure in which electrical connections are made in series and parallel, it is preferable that a bus bar of a collecting electrode be formed at the connection portion, since this increases the number of photoelectric conversion units. The solar cell module of the present invention includes, for example, a 4 mm thick polycarbonate multi-rib multilayer structure, an integrated amorphous silicon solar cell using a 0.1 mm thick polyester film substrate, polyvinylidene fluoride/ When constructed with a sealing material (thickness 0.3 mm) consisting of Al metal foil/polyvinylidene fluoride, the total thickness is at most 4.5 mm and the weight is approx.
^At 1.0Kg/m2, the impact resistance can withstand a 5m drop from a 500g steel ball. On the other hand, instead of the multilayer structure, the thickness
In the case of a solar cell with the same configuration using 3.2 mm tempered glass, the overall thickness is 3.7 mm, which is slightly thinner than the structure of the present invention, but the weight is significantly increased to approximately 9.0 kg/m ² , and the impact resistance is increased. A 225g steel ball falls to a height of 1.5m. As is clear from this fact, it was found that the solar cell module of the present invention can be made lighter without impairing its mechanical strength, and can also have a simpler laminate structure. The present invention will be explained below based on examples. <Example> Photovoltaic element FIG. 2 shows a side sectional view of a photovoltaic element of an example. In this example, a plurality of power generation units provided on a polymer film substrate 21 are connected in series, and a collector electrode bus bar is formed at the connection part. Almost the same except for The illustrated polymer film for the substrate 21 may be any polymer film that has the heat resistance necessary for amorphous silicon deposition, but preferably polyethylene terephthalate (PET) film,
Polyimide film or the like is used. The example in the diagram is
It uses PET film. As the metal electrode layer 22, an Al layer of about 0.5 μm and 30
A stainless steel (SUS) layer with a thickness of approximately Å is deposited sequentially on the substrate 21 using the sputtering method.
A SUS laminate was used. The amorphous silicon semiconductor layer 23 of the photovoltaic layer adopts a well-known pin-type structure, and is formed into a metal electrode layer using a glow discharge decomposition method using silane gas or the like similar to that disclosed in Japanese Patent Application Laid-Open No. 59-34668. No. 22 was deposited on the stainless steel layer. Next, an amorphous silicon semiconductor layer 2 is used to prevent short circuits between electrodes during division using the laser scribing method.
As an electrically insulating insulating resin layer 25 provided at the interface between 3 and the transparent electrode layer 24, an epoxy resin is applied to the amorphous silicon semiconductor layer 23 using a screen printing method in the groove portions to be divided into cells 20a using a laser. Set up in advance. Next, as the transparent electrode layer 24, an ITO (indium oxide/tin oxide) layer is deposited to a thickness of about 600 Å by electron beam evaporation or sputtering, and
We obtained a large-area amorphous thin-film solar cell with an Al/SUS amorphous silicon pin patterned epoxy resin layer/ITO structure. Next, this PETAl/SUS amorphous silicon pin patterned epoxy resin layer ITO structure amorphous solar cell 10cm x 10cm square cell was
A laser scans the above-mentioned insulating resin layer 25 made of an epoxy resin layer to melt and evaporate only the metal electrode layer 22 and the transparent electrode layer 24, respectively, and remove them as necessary to form the dividing grooves 26. This is filled with the same insulating resin as above, and three approximately 3
It was disassembled into cells 20a of cm x 10 cm square. In order to connect these three disassembled cells 20a in series, a comb-shaped collection electrode 27 made of conductive ink having a bus bar part and a finger part is screened onto the cell 20a as shown in FIG. It was installed using a printing method. After that, the connection point 28 of the bus bar part
A laser beam is irradiated to fuse and connect the collecting electrodes 27, that is, the transparent electrodes 24 of the adjacent cells 20a, and one metal electrode layer 22 to establish an electrical connection, and three cells 20a are connected in series as the photovoltaic element 20. We created an integrated amorphous solar cell. Covering structure The covering plate 10 that serves as the window and the support is made of Panlite Uni (trade name) manufactured by Teijin Kasei Ltd., manufactured by extrusion molding from polycarbonate resin, and is made of 110 mm x 110 mm.
It was cut into mm pieces using a tip saw. Figure 3,
As shown in FIG. 4, the panlite uni used is made by joining two sheets 12 and 13 with a thickness of 1 mm with an intermediate member 11 consisting of ribs with a thickness of 1 mm and a height of 7 mm provided at an interval of 30 mm. ×7mm prismatic cell chamber 14
It had a multi-rib structure with a total thickness of 9 mm and a weight of about 2 kg/m ² . Then, a moisture-resistant film 15 made of indium oxide and having a thickness of about 300 Å was provided on one side. Manufacture of module When laminating the multilayer plate 10 and the photovoltaic element 20 made of the integrated amorphous silicon solar cell described above, an ethylene vinyl acetate resin having a thickness of 0.4 mm is inserted as a filling layer 31 between the two. . On the other hand, on the opposite side of the photovoltaic element 20, a sealing material 40 was laminated as a second filling layer 32 via an ethylene vinyl acetate resin having a thickness of 0.4 mm. The sealing material 40 was made of aluminum metal foil with a thickness of 0.015 mm, ethylene vinyl acetate resin, and polyester film with a thickness of 0.075 mm.
A moisture-proof film with a layered structure was used. Next, this stacked body is sent between 90°C and 180°C hot rolls so that the multilayer board 10 is on the 90°C hot roll side.
The whole was thermocompressed to obtain a solar cell main module of the present invention. Next, this main body module was sealed with an aluminum frame 50 using phthyl rubber as the sealant 33 to form the following solar cell module shown in FIGS. 3 and 4. FIG. 3 is a plan view, and FIG. 4 is a sectional view taken along the line A-B. In addition, when producing these modules, the fifth
As shown in the figure, the photovoltaic element 20 and the multilayer plate 10 were bonded together so that the bus-bye of the collector electrode of the photovoltaic element 20 overlapped with the intermediate member 11 of the multilayer plate 10 to obtain the module of the example. In addition, as a comparative example, a module was created in which these components were pasted together so that they intersected each other at right angles. and AM1 (100mw/cm ² )
The cell performance of both modules was measured under solar simulator light. Table 1 shows the measurement results of cell performance.
Shown below.

[Table] As can be seen from the results in Table 1, in the module of the present invention, the busbar part i, which does not contribute to photoelectric conversion,
Since the series connection portion 28 overlaps the rib 11 of the intermediate member of the multilayer plate 10 of the support body, the reduction in the area of the photoelectric conversion region due to modularization is kept to the necessary minimum. As a result, short circuit current increases and conversion efficiency improves compared to the comparative example.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a bus bar and fingers of a photovoltaic element according to the present invention, FIG. 2 is a side sectional view of a photovoltaic element according to an embodiment, and FIG. 3 is a plan view of a solar cell module according to an embodiment. Figure 4 is Figure 3A
5 is an explanatory diagram of the laminated structure of the embodiment. 10: Multilayer board, 20: Photovoltaic element, 31,3
2: Filling layer, 40: Sealing material, 33: Sealing agent, 5
0: Frame.

Claims (1)

[Scope of Claims] 1. A support body consisting of a transparent multi-layer plate with a hollow structure, in which a plurality of transparent plates made of non-metallic materials are connected by intermediate members arranged at predetermined intervals, is laminated on the lighting side of the solar power generation element. A solar cell module characterized in that the bus bar of the collector electrode of the photovoltaic element and the intermediate member of the support are laminated so as to overlap. 2. Where the solar power generation element has an integrated configuration in which multiple power generation units installed on the same flexible electrically insulating substrate are connected in series and/or in parallel, and where the solar power generation elements are connected in series and/or in parallel. Claim 1, wherein the bus bar of the collector electrode is formed in the first aspect of the present invention.
The solar cell module described in Section 1. 3. The solar cell module according to claims 1 and 2, wherein all of the hollow portions of the transparent multilayer plate communicate with the outside, and the hollow portions are sealed so as to communicate with the atmosphere. 4. The solar cell module according to claim 3, wherein the intermediate member of the transparent multi-layer plate is ribs arranged at regular intervals, and the hollow portion is divided into parallel columnar cells. 5. The solar cell module according to claim 4, wherein the columnar cells are arranged to be inclined. 6. The solar cell module according to any one of claims 1 to 5, wherein the transparent multilayer plate is made of synthetic resin. 7. The solar cell module according to claim 6, wherein the transparent multilayer plate is made of polycarbonate resin. 8. The solar cell module according to claim 6 or 7, wherein the transparent multi-layer plate is a transparent multi-layer plate on which a transparent moisture-resistant film is formed on the side facing the photovoltaic element. . 9. The solar cell module according to any one of claims 1 to 8, wherein the transparent multilayer plate is a transparent multilayer plate on which a transparent scratch-resistant film is formed on the surface facing the atmosphere. 10. The solar cell module according to any one of claims 1 to 8, wherein the back side of the solar power generation element is sealed with a sealing material. 11 The flexible substrate is a polymer film,
11. The solar cell module according to claim 10, wherein the power generation unit is an amorphous semiconductor.