Patent Publication Number: US-2005126622-A1

Title: Solar cell module and method of producing the same

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a solar cell module and a method of producing the same, and more particularly, the present invention relates to a solar cell module which includes reinforcing members on a back of a solar cell panel.  
      2. Related Background Art  
      Solar energy is clean and inexhaustible energy and therefore it draws increasing attention year by year with depletion of fossil fuels and aggravation of environmental problems. At present, solar power generation systems utilizing solar energy for power generation are installed on various places such as general housing roofs and high-rise building walls.  
       FIG. 17  is a top plan view showing an example of a conventional solar cell module which has been widely spread in the market, and  FIG. 18  is a cross-sectional view taken along the line  18 - 18  in  FIG. 17 . In those figures, reference numeral  10  denotes a photovoltaic device,  11  denotes a covering material,  12  denotes a reinforcing member, and  13  denotes a frame. As shown in the figures, a conventional solar cell module includes a plurality of photovoltaic devices  10 , a covering material  11  which seals each of the photovoltaic devices  10 , a reinforcing member  12  which provides mechanical strength to avoid damaging the photovoltaic devices  10  from outside shock which they may receive during or after installation, and a frame  13  which covers end portions of the solar cell module and also serves as a fixing tool when fixing to a base for example. A back of the photovoltaic devices set sealed with the covering material  11  is reinforced with the plate-shaped reinforcing member  12  and such a laminated body is supported on and fixed to the frame  13 .  
      Sizes of such solar cell modules are so diverse, however, a solar cell module having a large area with large production of electricity for each solar cell module is often used in the case of a comparatively large installing area such as a power station or a roof of public facilities. The reason is that, in the case of the same output, it provides less work in electrical connection between solar cell modules, less work in fixing a solar cell module to a base, or. less cost for each watt of a solar cell module.  
      In contrast, a solar cell module with a large area receives larger strength, which may be exerted in strong winds or snow coverage, than that received by a solar cell module with a small area, and therefore solar cell modules of each maker are devised by all kinds of things to improve mechanical strength against such external stresses. A technique that improves mechanical strength of a solar cell module by providing an angle with an L-shaped cross-section on a back of the solar cell module is described in Japanese Patent Application Laid-Open No. H08-49377. A technique that improves mechanical strength of a solar cell module by using reinforced glass is also described in Japanese Patent Application Laid-Open No. H06-310748. Measures to increase the thickness of a reinforcing member such as glass or metal plate can be used instead of such techniques.  
      When mechanical strength of a solar cell module is improved with such techniques that increases the thickness of the reinforcing member provided on the back of the solar cell module or provides the angle with an L-shaped cross-section as described in Japanese Patent Application Laid-Open No. H08-49377, a weight of the solar cell module itself increases, thereby causing a worker&#39;s burden to increase in carrying and installing work, whereby there arises a problem in that work efficiency decreases. Moreover, when the weight of the solar cell module itself increases owing to increase in thickness of the reinforcing member etc., there also arises a problem in that a load exerted on a structure such as a roof or a wall on which the solar cell module is installed increases.  
      In addition, the use of a high mechanical strength material such as the reinforced glass as the reinforcing member as described in Japanese Patent Application Laid-Open No. H06-310748 can avoid to increase a weight of a solar cell module. However, the reinforced glass is used for special applications and is expensive because of less circulation in the market and therefore it is not preferable since the use causes the solar cell module to increase its manufacturing cost.  
      Further, when the reinforcing member of the solar cell module is composed of one sheet of glass or a metal plate, external stresses exerted on the solar cell module concentrate on the end side midsections of the reinforcing member. Consequently, the material and thickness of the reinforcing member have to be selected based on the end side midsections. However, the selection provides the rest of the end side midsections with excessive mechanical strength. This is very useless.  
     SUMMARY OF THE INVENTION  
      The present invention has been made to solve the aforementioned problems, and an object of the present invention is to provide a solar cell module and a method of producing the same which can improve mechanical strength and provide less weight and high productivity.  
      In order to achieve the above object, according to one aspect of the present invention, there is provided solar cell module, including: a solar cell panel in which a photovoltaic device for performing photoelectric conversion is sealed with a covering material; a plurality of reinforcing members which are in contact with a back of the solar cell panel; a perpendicular portion formed on an opposed end portion of each of the reinforcing members at least along one of a longitudinal direction and a width direction of the solar cell panel as well as extended with respect to an installation portion of a structure; and a frame provided on an opposed end portion of the solar cell panel perpendicular to the perpendicular portion of the reinforcing member.  
      In further aspect of the solar cell module, the perpendicular portion of the reinforcing member is preferably formed by bending.  
      In further aspect of the solar cell module, the perpendicular portion of the reinforcing member on one side is preferably in contact with the perpendicular portion of the reinforcing member on the other side in two adjacent reinforcing members.  
      In further aspect of the solar cell module, the solar cell panel preferably includes a photovoltaic device set which is obtained by electrically connecting at least one photovoltaic device.  
      In further aspect of the solar cell module, the frame is preferably provided on only the end portion on the long side or the end portion on the short side of the solar cell module.  
      In further aspect of the solar cell module, the frame preferably includes an insertion portion into which the solar cell panel is inserted.  
      In further aspect of the solar cell module, a part of the insertion portion preferably includes a cutout into which the perpendicular portion of the reinforcing member is inserted.  
      In further aspect of the solar cell module, it is preferable that the solar cell panel include at least one bypass diode and the bypass diode be inserted into the insertion portion of the frame.  
      In further aspect of the solar cell module, the solar cell panel and the reinforcing member are preferably fixed with an adhesive or a double-side adhesive tape.  
      In further aspect of the solar cell module, it is preferable that the solar cell panel has a light-receiving surface and a non-light-receiving surface and at least one of the light-receiving surface and the non-light-receiving surface be sealed with the covering material.  
      According to another aspect of the present invention, there is provided a method of producing a solar cell module which includes a plurality of reinforcing members with perpendicular portions on a back of a solar cell panel in which photovoltaic devices for performing photoelectric conversion are sealed with a covering material, the method including the steps of: forming the solar cell panel; forming an installation surface of the solar cell panel by placing a plurality of the reinforcing members with the perpendicular portions; and installing the solar cell panel on the installation surface.  
      In further aspect of the method of producing a solar cell module, the step of forming the solar cell panel preferably includes a step of sealing a photovoltaic device set which is composed of an electrically connected single photovoltaic device or a plurality of the photovoltaic devices with a covering material.  
      In further aspect of the method of producing a solar cell module, the method preferably further includes a step of inserting the frame into the end portion of the solar cell module after the step of installing the solar cell panel on the installation surface.  
      In further aspect of the method of producing a solar cell module, wherein the frame is preferably provided on only the end portion on the long side or the end portion on the short side of the solar cell module in the step of inserting the frame into the end portion of the solar cell module.  
      According to the present invention, the solar cell module includes a plurality of reinforcing members which are in contact with a back of a solar cell panel, each reinforcing member provides a perpendicular portion which is formed on the opposed end portion along a longitudinal or width direction of the solar cell panel as well as extended with respect to an installation surface of a structure, and consequently a number of perpendicular portions are arranged on the back of the solar cell panel. As a result, mechanical strength is improved in comparison with a solar cell module provided with a tabular reinforcing member. Moreover, as the mechanical strength of the reinforcing member increases by forming the perpendicular portions, the thickness of the reinforcing member can be reduced, thereby permitting the solar cell module to reduce its weight. In addition, frames are installed on the opposed end portions of the solar cell panel perpendicular to the perpendicular portions of the reinforcing members so that the mechanical strength of the solar cell module significantly increases.  
      That is, a solar cell module and a method of producing the same can offer advantages in improving mechanical strength as well as providing less weight and high productivity.  
      Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a top plan view seen from a light-receiving surface side showing a solar cell module according to an embodiment of the present invention;  
       FIG. 2  is a rear view seen from a non-light-receiving surface side showing the solar cell module according to the embodiment;  
       FIG. 3  is a cross-sectional view taken along the line  3 - 3  in  FIG. 1 ;  
       FIG. 4  is a top plan view seen from a light-receiving surface side showing a solar cell module according to an embodiment of the present invention;  
       FIG. 5  is a rear view seen from a non-light-receiving surface side showing the solar cell module according to the embodiment;  
       FIG. 6  is a cross-sectional view taken along the line  6 - 6  in  FIG. 4 ;  
       FIG. 7  is a cross-sectional view taken along the line  7 - 7  in  FIG. 4 ;  
       FIG. 8  is an electrical connection diagram for explaining a solar cell module according to the example;  
       FIG. 9  is a perspective view showing a reinforcing member used in a solar cell module according to the example;  
       FIG. 10  is a top plan view seen from a light-receiving surface side showing a solar cell panel according to the example;  
       FIG. 11A  is a rear view seen from a non-light-receiving surface side showing the solar cell panel according the example, and  FIG. 11B  is an enlarged view showing a main part encircled in  FIG. 11A ;  
       FIG. 12  is a cross-sectional view taken along the line  12 - 12  in  FIG. 10 ;  
       FIG. 13  is a top plan view seen from a light-receiving surface side showing a photovoltaic device according to the example;  
       FIG. 14  is a rear view seen from a non-light-receiving surface side showing the photovoltaic device according to the example;  
       FIG. 15  is a cross-sectional view taken along the line  15 - 15  in  FIG. 13 ;  
       FIG. 16  is a perspective view showing an assembling structure of a solar cell module according to the embodiment;  
       FIG. 17  is a top plan view showing an example of a conventional solar cell module; and  
       FIG. 18  is a cross-sectional view taken along the line  18 - 18  in  FIG. 17 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Best embodiments for carrying out the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.  
       FIG. 1  is a top plan view seen from a light-receiving surface side showing a solar cell module according to an embodiment of the present invention and  FIG. 2  is a rear view seen from a non-light-receiving surface side showing the solar cell module according to the embodiment.  FIG. 3  is a cross-sectional view taken along the line  3 - 3  in  FIG. 1 . In those figures, reference numeral  20  denotes a photovoltaic device,  21  denotes a covering material,  22  denotes a reinforcing member,  22   a  denotes a perpendicular portion,  22   b  denotes an installation surface,  22   c  denotes a turnback portion,  23  denotes a frame,  24  denotes a solar cell panel,  25  denotes an adhesive,  26  denotes a junction box, and  27  denotes an output cable.  
      As shown in the figures, the solar cell module according to the present invention includes a plurality of the reinforcing members  22  which are in contact with a back of the solar cell panel  24  in which the photovoltaic device  20  for performing a photoelectric conversion is sealed with the covering material. Each reinforcing member  22  provides the perpendicular portion  22   a  which is formed on the opposed end portions along a longitudinal or width direction of the solar cell panel  24  as well as extended with respect to an installation portion of a structure such as a roof or a wall. The solar cell module includes the frame  23  provided on the opposed end portions of the solar cell panel  24  perpendicular to the perpendicular portion  22   a  of the reinforcing member  22 . In this embodiment, the perpendicular portion  22   a  of the reinforcing member  22  is formed along the width direction of the solar cell panel  24 , the frame  23  is provided on the end portion on the long side of the solar cell panel  24 , and the reinforcing member  22  is inserted into the frame  23  so that the perpendicular portion  22   a  of the reinforcing member  22  is arranged perpendicular to the frame  23 .  
      A plurality of the reinforcing members  22  having the perpendicular portions  22   a  mentioned above are placed in the installation portion of the structure so that the adjacent perpendicular portions  22   a  of the reinforcing members contact each other, and an installation surface  22   b  of the solar cell panel  24  is provided on those reinforcing members  22 .  
      The solar cell panel  24  is fixed to the above-mentioned installation surface  22   b  with a double-side adhesive tape or adhesive. 25 . The above-mentioned solar cell panel  24  is composed of a photovoltaic device set formed by electrically connecting a plurality of the photovoltaic devices  20  and the covering material  21  for sealing the photovoltaic device set.  
      In addition, the junction box  26  and the output cable  27  for outputting generated power outside are provided on the non-light-receiving surface of the solar cell module.  
      The individual constituent elements of the solar cell module according to the embodiment will be described below in detail.  
      (Photovoltaic Device)  
      Examples of such a photovoltaic device  20  according to the present invention include a single-crystal silicon photovoltaic device, a polycrystalline silicon photovoltaic device, a microcrystal silicon photovoltaic device, an amorphous silicon photovoltaic device, and a polycrystalline compound photovoltaic device. A typical photovoltaic device suitably used out of those devices includes a transparent electrode layer, a photoelectric conversion layer, a back reflecting layer, and a back electrode layer from a light-receiving surface side, and electrodes for outputting generated electricity are provided in part. The transparent electrode layer, the photoelectric conversion layer, the back reflecting layer, and the back electrode layer will be described below in detail.  
      The transparent electrode layer transmits light as an electrode of light incidence side and also serves as an antireflection film by optimising the film thickness. The transparent electrode layer is required to have high transmittance and low electrical resistance at a sorbable wavelength range of the photoelectric conversion layer. Preferable examples of a material used for the layer include conductive oxide such as In 2 O 3 , SnO 2 , ITO (In 2 O 3 +SnO 2 ), ZnO, CdO, Cd 2 SnO 4 , TiO 2 , Ta 2 O 5 , Bi 2 O 3 , MoO 3 , or Na x WO 3  or a mixture of the materials mentioned above. Suitably used as a method of forming the transparent electrode layer is a sputtering method with sputtering gas which contains a small amount of oxygen.  
      The photoelectric conversion layer converts light to electricity. It is possible to use one of the following materials as the material of the photoelectric conversion layer: V-group elements such as Si, C, and Ge, IV-group element alloys such as SiGe and SiC, III-V-group compounds such as GaAs, InSb, GaP, GaSb, InP, and InAs, II-VI-group compounds such as ZnSe, ZnS, CdS, CdSe, and CdTe, and I-III-VI-group compounds such as CuInSe. However, the material of the photoelectric conversion layer is not limited to such materials. The photoelectric conversion layer forms at least one pair of a pn junction, a pin junction, a hetero junction, or a Schottky barrier. Moreover, examples of a suitable method of forming the photoelectric conversion layer include various kind of chemical vapor deposition (referred to as CVD) methods such as a microwave plasma CVD method, very high frequency (referred to as VHF) plasma CVD method, and radio-frequency (referred to as RF) plasma CVD method.  
      The back reflecting layer functions as a light reflecting layer which reflects light, which could not be absorbed in the photoelectric conversion layer, on the photoelectric conversion layer again. It is possible to use one of the following materials as the material of the back reflecting layer: metals such as Au, Ag, Cu, Al, Ni, Fe, Cr, Mo, W, Ti, Co, Ta, Nb, and Zr, or alloys such as stainless steel. However, of those materials, metal having high reflectivity such as Al, Cu, Ag, or Au is particularly preferable.  
      The back electrode layer functions as a collecting electrode for collecting electric charge generated on the non-light-receiving surface side of the photoelectric conversion layer. Examples of a material of the back electrode layer include metals such as Al, Au, Ag, Cu, Ti, Ta, and W. However, the material of the back electrode layer is not limited to such materials. Preferable examples of a formation method for the back electrode layer include the chemical vapor deposition method and the sputtering method. In addition, suitably used as the back electrode layer is a conductive substrate which functions as a supporting substrate for supporting each of the layers so that the layers are not damaged by forces exerted from outside. It is possible to use one of the following materials as a specific material of the conductive substrate: metals such as Fe, Ni, Cr, Al, Mo, Au, Nb, Ta, V, Ti, Pt, and Pb, or a thin film of alloys of these metals and its complex. However, the material of the conductive substrate is not limited to such materials.  
      (Photovoltaic Device Set)  
      A photovoltaic device set denotes a series connection body or a parallel connection body of photovoltaic devices formed by electrically connecting a plurality of photovoltaic devices.  
      (Solar Cell Panel)  
      In the present invention, a solar cell panel denotes a generating body in which a single photovoltaic device or the aforementioned photovoltaic device set is sealed with a covering material having environment resistance.  
      (Covering Material)  
      The covering material is composed of a surface member which is arranged on the light-receiving surface side of the photovoltaic devices, a back member which is arranged on the non-light-receiving surface side, and a sealing material which is arranged between the surface member and the back member.  
      Suitably used as a material of the surface member is glass or a fluoride polymer film. However, the material of the surface member is not limited to such materials. Examples of a fluoride polymer include polyvinylidene fluoride (referred to as PVDF), polyvinyl fluoride (referred to as PVF), ethylene-tetrafluoroethylene (referred to as ETFE) copolymer, polychlorotrifluoroethylene (referred to as PCTFE), chlorotrifluoroethylene-ethylene (referred to as ECTFE) copolymer, parfluoro(alkyl vinyl ether)-tetrafluoroethylene (referred to as PFA) copolymer, hexafluoropropylene-tetrafluoroethylene (referred to as FEP) copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, and a complex of two or more of these materials. The ETFE as one of such materials is preferably used because of suitable surface member for the solar cell module from the viewpoint of transparency as well as simultaneous pursuit of weather resistance and mechanical strength. Furthermore, one of the reasons why the EPFE is selected is that the ETFE is easy to generate a reaction product on the film surface by means of discharge treatment.  
      The back member is used to protect the photovoltaic devices, to prevent moisture from entering, and to maintain electrical insulation from outside. Preferable as a material of the back member is a material that can maintain sufficient electrical insulation, is superior in long durability, and can resist thermal expansion or thermal contraction. Examples of suitably used materials include a polyvinyl fluoride film, nylon film, polyethylene terephthalate film, and glass plate.  
      The sealing material is used for sealing the photovoltaic devices, for preventing the elements from a severe external environment such as temperature change, humidity, or shock, and for maintaining adherence between the surface member or the back member and the devices. Examples of a material of the sealing material include an ethylene-vinyl accetate (referred to as EVA) copolymer resin, an ethylene-methyl acrylate (referred to as EMA) copolymer resin, an ethylene-ethyl acrylate (referred to as EEA) copolymer resin, an ethylene-methacrylic acid (referred to as EMAA) copolymer resin, an ionomer resin, and a polyvinyl butyral resin. However, of these materials, the EVA resin is suitably used because it has balanced physical properties for use in solar cells, for example, weather resistance, adhesiveness, filling property, heat resistance, cold resistance, and impact resistance.  
      (Reinforcing Member)  
      The reinforcing member  22  functions to provide mechanical strength to the solar cell panel  24  so that the photovoltaic devices are not subject to damage by external stress during or after installation. The reinforcing member  22  according to the present invention includes at least the installation surface  22   b  for installing the solar cell panel  24  and the perpendicular portions  22   a  provided perpendicular to the installation surface  22   b.  In such a structure, the perpendicular portions  22   a  function to restrain flexure of the installation surface  22   b  due to any external stress. In addition, the provision of the turnback portion  22   c  on the end portion of the above-mentioned perpendicular portion  22   a  is desirable to further restrain the flexure.  
      Examples of a suitable material of the reinforcing member  22  include a galvanized steel plate, steel plate including weather resistance material such as a fluorocarbon resin or polyvinyl chloride, and a stainless steel plate. In addition, a metal sheet or plate is particularly preferable because the perpendicular portion  22   a  can be formed with ease by bending, but it is not limited to such materials.  
      Furthermore, the above-mentioned perpendicular portions  22   a  are provided at least on the end portion on the long side or the end portion on the short side of the reinforcing member  22 , where at the adjacent two reinforcing members  22 ,  22 , one perpendicular portion  22   a  of the reinforcing member  22  is in contact with the other perpendicular portion  22   a  of the reinforcing member  22 . In this structure, when external stress is exerted on the solar cell module, the perpendicular portions  22   a  provided on the reinforcing member  22  tend to be deformed; however, the perpendicular portions of the adjacent two reinforcing members  22  are in contact with each other and consequently deformation of one perpendicular portion  22   a  is restrained by the other perpendicular portion  22   a,  thereby improving flexibility of the solar cell module against the external stress.  
      When a solar cell panel  24  is installed on an installation surface of one plate of reinforcing member having many perpendicular portions, similarly to the present invention, the solar cell module can improve mechanically. However, size per plate of reinforcing member becomes larger, so that it requires a large-scale processing device with less productivity. Moreover, one plate of reinforcing member having many perpendicular portions causes infiltration of moisture at the interface between the solar cell panel  24  and the reinforcing member, and thus the moisture tends to accumulate on the perpendicular portions. This is because the perpendicular portion is bent into a V-shape and hence the bottom of the perpendicular portion becomes closed. Consequently, the moisture infiltrated has nowhere to escape and stays there for long time, thereby causing the reinforcing member to rust or to accelerate hydrolysis of the covering material. In the present invention, since a plurality of the reinforcing members are placed apart from each other, the moisture infiltrated at the interface between the solar cell panel  24  and the reinforcing member  22  can be drained to the outside inma short time.  
      Furthermore, in a method of providing L-shaped angle on a tabular reinforcing member, perpendicular portions can also be provided on the back of the solar cell module, and therefore such a structure can improve mechanical strength similarly to the present inrvention. The above-mentioned angle, however, is required to have adhesive face with respect to the reinforcing member other than the perpendicular portions. In the present invention, the reinforcing member  22  itself has the perpendicular portion  22   a,  thus the adhesive face mentioned above is not required and the weight can be reduced by the adhesive face while similar mechanical strength is maintained.  
      (Frame)  
      Preferably, the solar cell module can be directly fixed to the base or other supporting member by screws without using fixing tool when the frame  23  is provided on the end portion of the solar cell module. The frame  23  can use a channel-shaped aluminum frame, for example, which has a concave portion (insertion portion) for inserting the solar cell panel  24 .  
      The above-mentioned frame  23  may be provided only on either the end portion on the long side or the end portion on the short side of the solar cell module, and accordingly this structure enables further reduction in weight of the solar cell module. Furthermore, when the reinforcing member  22  is inserted into the frame  23  so that the above-mentioned perpendicular portion  22   a  is arranged perpendicularly to the frame  23 , preferably, the attachment of the reinforcing members becomes more secure.  
      In addition, provision of the insertion portion in the frame  23  for receiving the solar cell panel  24  and the installation surface  22   b  of the above-mentioned reinforcing member  22  permits to support the solar cell panel  24  and the reinforcing member  22 . Furthermore, provision of a cutout in the insertion portion of the frame  23  for inserting the perpendicular portions  22   a  of the reinforcing member  22  permits to connect the reinforcing member  22  with the frame  23  with ease.  
      When a bypass diode provided to the solar cell panel  24  is placed in the insertion portion of the frame  23 , breakage due to external stress degradation or solar insolation can be prevented.  
      (Adhesive/Double-Side Adhesive Tape)  
      The adhesive or double-side adhesive tape is used to fix the solar cell panel  24  to the installation surface  22   b  of the reinforcing member  22 , and required to have excellent weather resistance and excellent water resistance. As a specific material of the adhesive or double-side adhesive tape, there are, for example, a silicon adhesive, an epoxy adhesive, an acryl double-side adhesive tape, and butyl double-side adhesive tape.  
      A method of producing a solar cell module including the plurality of reinforcing members  22  with perpendicular portions on the back of the solar cell panel  24  in which the photovoltaic devices  20  for performing photoelectric conversion are sealed with a covering material according to an embodiment of the present invention, includes the steps of: forming the solar cell panel  24 ; forming the installation surface  22   b  of the solar cell panel  24  by placing the plurality of reinforcing members  22  with the perpendicular portions  22   a,;  and installing the solar cell panel  24  on the installation surface  22   b.    
      In the above-mentioned method of producing the solar cell module, it is preferable that the step of forming the solar cell panel  24  includes a step of sealing a photovoltaic device set which is composed of the photovoltaic device  20  or the plurality of photovoltaic devices  20  that are electrically connected with a covering material. Moreover, it is preferable to include a step of inserting the frame  23  into the end portion of the solar cell module after the step of installing the solar cell panel  24  on the installation surface  22   b.  Furthermore, in the step of inserting the frame  23  into the end portion of the solar cell module, the frame  23  may be provided on only the end portion on the long side or the end portion on the short side of the solar cell module.  
      As described above, according to this embodiment, the solar cell module can improve its mechanical strength without increasing the thickness of the reinforcing member  22  and can reduce its weight. Moreover, since the conventional reinforcing member is made of one flat plate, local stress concentration is caused in the reinforcing member when the solar cell module is applied with external stress, while such a solar cell module composed of the plurality of reinforcing members  22  can relieve stress concentration. Furthermore, this structure is superior in productivity to a solar cell module having a single plate of reinforcing member with a plurality of perpendicular portions.  
      In addition, the present invention is effective for not only the solar cell module with large area but also the solar cell module with small area.  
      Examples of the present invention will be described in detail below, but the present invention is not limited to those examples.  
       FIG. 4  is a top plan view seen from a light-receiving surface side showing a solar cell module according to the example of the present invention, and  FIG. 5  is a rear view seen from a non-light-receiving surface side showing the solar cell module according to the example of the present invention. Moreover,  FIG. 6  is a cross-sectional view taken along the line  6 - 6  in  FIG. 4 , and  FIG. 7  is a cross-sectional view taken along the line  7 - 7  in  FIG. 4 . Furthermore,  FIG. 8  is an electrical connection diagram for explaining a solar cell module according to the example of the present invention. In these figures, reference numeral  30  denotes a photovoltaic device,  31  denotes a solar cell panel,  32  denotes a reinforcing member,  32   a  denote a perpendicular portion,  32   b  denotes an installation surface,  32   c  denotes a turnback portion,  33  denotes a frame,  34  denotes a filler,  35  denotes an adhesive,  36   a  denotes a bypass diode, and  37  denotes a covering material.  
      As shown in the figures, a solar cell module according to this example includes a plurality of the reinforcing members  32  which are in contact with the back of the solar cell panel  31  in which the photovoltaic device  30  for performing a photoelectric conversion is sealed with the covering material, each reinforcing member  32  provides the perpendicular portion  32   a  formed on the opposed end portions along a width direction of the solar cell panel  31  as well as extended with respect to an installation portion of a structure such as a roof or a wall, and the frame  33  is provided on the opposed end portions along a longitudinal direction of the solar cell panel  24  perpendicular to the perpendicular portion  32   a  of the reinforcing member  32 .  
       FIG. 9  is a perspective view showing a reinforcing member used in a solar cell module according to this example. As shown in the figures, the solar cell module according to this example includes the eight reinforcing members  32  having the perpendicular portion  32   a,  the installation surface  32   b,  and the turnback portion  32   c.  The reinforcing member  32  is made of galbarium steel plate in which the perpendicular portion  22   a  formed by a roller former is respectively provided on each of the end portions on the long side of the reinforcing member  32 . The eight reinforcing members  32  are placed so that the perpendicular portions  32   a  of the adjacent reinforcing members  32  are in contact with each other, and each of the installation surfaces  32   b  of the respective reinforcing members  32  forms the installation surface  32   b  for installing the solar cell panel  31 . The solar cell panel  31  is fixed on the installation surface  32   b  by the adhesive  35  such as silicone sealant.  
       FIG. 10  is a top plan view seen from a light-receiving surface side showing the solar cell panel according to this example,  FIG. 11A  is a rear view seen from a non-light-receiving surface side, and  FIG. 11B  is an enlarged view showing a main part encircled in  FIG. 11A . In these figures, reference numeral  30  denotes the photovoltaic device,  36  denotes a bypass connection portion,  36   a  denotes a bypass diode,  36   b  denotes a diode terminal,  36   c  denotes a solder,  37  denotes a covering material,  38  denotes a lead electrode,  38   a  denotes an exposed portion of the lead electrode,  300  and  301  denote a photovoltaic device, and  300   g  and  301   g  denote an electrode.  
      The solar cell panel according to this example constitutes a photovoltaic device set in which sixteen amorphous silicon-based photovoltaic devices  30  are connected in series. In such a structure, a gap between the photovoltaic devices is set to 2 mm in the longitudinal direction and is set to 3 mm in the width direction perpendicular to the longitudinal direction.  
      When the solar cell panel is shadowed partly, a reverse bias voltage is applied to a photovoltaic device, which is in non-power-generation condition due to no exposure to the sun light, through a load from a photovoltaic device that is connected in series to the photovoltaic device in power-generation condition, thereby causing the photovoltaic device to be damaged, and therefore the bypass diode  36   a  is provided at each of the photovoltaic devices on the end portions of the solar cell panel. As shown in  FIG. 11B , the above-mentioned bypass diode  36   a  is electrically connected through the diode terminal  36   b  to the electrode  300   g  which is provided on the non-light-receiving surface of the photovoltaic device  300  on one side and to the electrode  301   g  which is provided on the non-light-receiving surface of the adjacent photovoltaic device  301  with the solder  36   c.    
      Moreover,  FIG. 12  is a cross-sectional view taken along the line  12 - 12  in  FIG. 10 . In  FIG. 12 , reference numeral  30  denotes the photovoltaic device,  30   f  and  30   g  denote the electrode,  31  denotes the photovoltaic device,  37  denotes the covering material,  37   a  denotes a surface member,  37   b  denotes a sealing material, and  37   c  denotes a back member.  
      As shown in the figure, each photovoltaic device  30  constituting the photovoltaic device set mentioned above is protected by the covering material  37 . An ETFE film is arranged as the surface member  37   a  on the light-receiving surface side of the above-mentioned photovoltaic device set, a polyethylene terephthalate (referred to as PET) film is arranged as the back member  37   c  on-the non-light-receiving surface side, and these films and the photovoltaic device  30  are bonded by EVA as the sealing material  37   b.    
      As shown in  FIG. 11A , the above-mentioned photovoltaic device set is provided with the lead electrode  38  for taking out the generated electricity, and a part of the lead electrode  38   a  is exposed from the covering material  37  in the non-light-receiving surface of the solar cell panel.  
      Now,  FIG. 13  is a top plan view seen from a light-receiving surface side showing a photovoltaic device according to this example, and  FIG. 14  is a rear view seen from a non-light-receiving surface side showing a photovoltaic device according to this example. Moreover,  FIG. 15  is a cross-sectional view taken along the line  15 - 15  in  FIG. 13 . In these figures, reference symbol  30   a  denotes a resin layer,  30   b  denotes a transparent electrode layer,  30   c  denotes a photoelectric conversion layer,  30   d  denotes a back reflecting layer,  30   e  denotes a back electrode layer,  30   f  denotes a positive electrode, and  30   g  denotes a negative electrode.  
      As shown in the figures, the photovoltaic device  30  is composed of at least the resin layer  30   a,  the transparent electrode layer  30   b,  the photoelectric conversion layer  30   c,  the back reflecting layer  30   d,  and the-back electrode layer  30   e  from the light-receiving surface side. The resin layer  30   a  is made of acrylic urethane resin. The transparent electrode layer  30   b  is made of ITO. The photoelectric conversion layer  30   c  is made of P-I-N-based amorphous silicon. The back reflecting layer  30   d  is made of ZnO and AI. The back electrode layer  30   e  is made of stainless steel. Furthermore, the positive electrode  30   f  made of silver plated copper foil is provided on the light-receiving surface of the transparent electrode layer  30   b,  and the negative electrode  30   g  made of copper foil is provided on the non-light-receiving surface of the back electrode layer  30   e.    
      In addition,  FIG. 16  is a perspective view showing an assembling structure of a solar cell module according to this example. In  FIG. 16 , reference numeral  31  denotes a solar cell panel,  32  denotes a reinforcing member,  32   a  denotes perpendicular portions,  33  denotes a frame,  33   a  denotes an insertion portion, and  33   b  denotes a cutout. As shown in the figure, the frame  33  made of aluminum alloy is provided on the end portion on the long side of the solar cell module. The frame  33  includes the insertion portion  33   a  for inserting the reinforcing member  32  inside, and also includes the cutout  33   b  on the part of the insertion portion  33   a.  The installation surface  32   b  of the reinforcing member  32  and the solar cell panel  31  are inserted into the above-mentioned insertion portion  33   a,  and the perpendicular portion  32   a  of the reinforcing member  32  is inserted into and fixed to the above-mentioned cutout  33   b.  An adhesive such as silicone sealant which is not shown in the figure is filled in the insertion portion  33   a  of the frame  33  for preventing the reinforcing member  32  from falling off.  
      Moreover, the above-mentioned bypass diodes  36 a are put in the insertion portion  33   a  of the above-mentioned frame so that the bypass diode  36   a  may not be damaged by an external stress.  
      Furthermore, two through holes each having a diameter of 15 mm, which are not shown in the figure, are provided on a part of the reinforcing member  32 , and the positions of these through holes conform with those of the above-mentioned lead electrodes  38  exposed from the solar cell panel  31  to fix them by adhering. As shown in  FIG. 5 , those through holes are covered by the junction box  39   a  made of denatured polyphenylether (referred to as PPE). The output cable  39   b  is soldered to the lead electrode  38   a  and is stuck out through the junction box  39   a.  Moreover, an adhesive such as silicone sealant is filled in the junction box  39   a.    
      Now, a method of producing a solar cell module of this example will be described.  
      A method of producing a solar cell module of this example includes the steps of: forming a solar cell panel; forming an installation surface by placing a reinforcing member with a perpendicular portion; installing the solar cell panel on the installation surface; providing a frame on an end portion of the solar cell module; and fixing an output cable and a junction box, and each of the steps will be described below in-detail.  
      The step of forming a solar cell panel includes a work of forming a photovoltaic device set in which a plurality of photovoltaic devices are connected in series, a work of providing a bypass diode on each of the photovoltaic devices, a work of providing a lead electrode on the photovoltaic device set, and a work of sealing the photovoltaic device set with a covering material.  
      In order to form the photovoltaic device set, eight pieces of photovoltaic devices are arranged first in series with a 2 mm gap between adjacent devices, and the electrodes provided on the light-receiving surface of the adjacent photovoltaic device on one side are electrically connected sequentially to the electrodes provided on the non-light-receiving surface on the other side with solder, thereby forming a series connection body of photovoltaic devices. Next, the above-mentioned series connection bodies are placed in two rows spaced with a 3 mm gap, and a positive electrode of an end portion of the series connection body on one side and a negative electrode of an end portion of the series connection body on the other side are electrically connected to a single copper foil to form a photovoltaic device set. In this configuration, the above-mentioned copper foil is 5.5 mm wide and 0.2 mm thick.  
      The work of providing the bypass diode is to form a diode with terminals first by soldering the diode terminals made of L-shaped copper foil to a Schottky barrier type diode. Then, the above-mentioned diode with terminals is arranged on the corner portion of each photovoltaic device. At that time, the diode with terminals is arranged so as to be placed on the end portion on the long side of the photovoltaic device set. Finally, in each of the diodes with terminals, a diode terminal on one side is electrically connected to the electrode provided on the non-light-receiving surface of the photovoltaic device, and a diode terminal on the other side is electrically connected to the electrode provided on the non-light-receiving surface of the adjacent photovoltaic device, respectively. In such a structure, when there exists no adjacent photovoltaic device, a diode terminal on the other side is electrically connected to an extended portion of the electrode provided on the light-receiving surface of the photovoltaic device.  
      The work of providing the lead electrode on the photovoltaic device set is carried out by: electrically connecting a copper foil to the positive electrode and the negative electrode of the photovoltaic device set; and leading the above-mentioned copper foil to the non-light-receiving surface side of the photovoltaic device set.  
      The work of sealing the photovoltaic device set with the covering material is performed using a lamination apparatus of a double vacuum system. The covering material is composed of the PET film (thickness:50 μm), the EVA film (thickness:400 μm) on the PET film, the photovoltaic device set (the light-receiving surface is placed upward) on the EVA film, the EVA film (thickness: 400 μm) on the light-receiving surface of the photovoltaic device set, and the ETFE film (thickness:25 μm) on the EVA sheet.  
      A stacked structure composed of the covering materials and the photovoltaic devices is put into an oven at 150° C. and heated through vacuum heating for 40 minutes, and consequently each covering material and the photovoltaic device set are integrated. After that, the sealing work is completed when the stacked structure is taken out from the oven and cooled at room temperature.  
      In such a configuration, the PET film and EVA film provided on the non-light-receiving surface side of the lead electrode each have a through hole with a diameter of 20 mm and are positioned with the lead electrode in laminating. Thus, the lead electrode is exposed after laminating.  
      Next, the eight reinforcing members provided with the perpendicular portion formed by a roller former are placed so that respective perpendicular portions are in contact with the perpendicular portion of the adjacent reinforcing member, and therefore the installation surface of the solar cell panel is formed. At that time, each of the reinforcing members is fixed temporarily with tape so as not to be misaligned. In such a configuration, one of the eight reinforcing members has two through holes of a 15 mm diameter.  
      The solar cell panel is fixed on the installation surface of the reinforcing member with an adhesive such as silicone sealant. First, silicone sealant is applied to the installation surface in a longitudinal direction in four rows. Next, the solar cell panel is installed on the installation surface and pressed sufficiently so that the adhesive spreads. At that time, it should be confirmed that the exposed portion of the lead electrode provided on the solar cell panel and the through holes provided in the reinforcing member are aligned at the same positions.  
      After the silicone sealant existing at the interface between the solar cell panel and the installation surface of the reinforcing member has been hardened, the work of providing the frame on the end portion on the long side of the solar cell module is carried out. First, the silicone sealant is applied to the end portion of short side of the non-light-receiving surface side of each reinforcing member. Next, the solar cell panel and the reinforcing member are inserted into the insertion portion of the frame and the perpendicular portion of the reinforcing member is inserted into the cutout, respectively.  
      Finally, the work of fixing the output cable and the junction box is carried out. The above-mentioned junction box is composed of a frame body and a cover body, and the frame body has a through hole for taking out an output cable. First, the frame body is fixed to the non-light-receiving surface of the reinforcing member with a double-side adhesive tape. Next, the output cable is inserted into the through hole of the frame body and the output cable and the lead electrode are electrically connected. After that, the work is completed when silicone resin is filled in the frame body and the cover body is fixed.  
      This application claims priority from Japanese Patent Application No. 2003-413072 filed Dec. 11, 2003, which is hereby incorporated by reference herein.