Solar cell module and panel, and method

Abstract

A laminated module or panel of solar cells and a laminating method for making same comprise an optically transparent top layer and a thermally conductive rear sheet of melt flowable insulating thermoplastic. Solar cells are encapsulated between the top layer and the rear sheet, and electrical connections are provided between a front surface of one solar cell and the back surface of another solar cell. Light passing through the transparent top layer impinges upon the solar cells. Electrical connections may be provided by melt flowable electrically conductive molecularly flexible thermoplastic adhesive or by metal strips or by both. The laminated module in one embodiment may be molecularly flexible and/or may exhibit a particular flexural modulus.

What is claimed is: 
     
         1 . A laminated module of solar cells having front and back surfaces comprising:
 a plurality of solar cells having front and back surfaces to which electrical connection is to be made;   a top layer of an optically transparent electrically insulating material adjacent to and having adhesion to the front surfaces of solar cells,   whereby light may pass through said optically transparent top layer to impinge upon the front surfaces of said plurality of solar cells;   a thermally conductive rear sheet including a melt flowed melt flowable thermally conductive and electrically insulating thermoplastic adhesive material adjacent to and having adhesion to the back surfaces of solar cells;   a plurality of electrical connections, each electrical connection being between the front surface of one of said plurality of solar cells and the back surface of another of said plurality of solar cells,   whereby ones of said plurality of solar cells are electrically connected in series; and   said top layer, said thermally conductive rear sheet and said plurality of solar cells being melt flow laminated with at least the melt flowed thermally conductive thermoplastic adhesive material of said thermally conductive rear sheet melt flow laminating to said plurality of solar cells;   said top layer adhering to the front surfaces of said plurality of solar cells and said thermally conductive rear sheet adhering to the back surfaces of said plurality of solar cells,   whereby heat from said plurality of solar cells can be transferred via said thermally conductive rear sheet.   
     
     
         2 . The laminated module of solar cells of  claim 1  further comprising:
 a thermally conductive metal sheet thermally coupled to an exposed rear surface of said melt flowable rear sheet. 
 
     
     
         3 . The laminated module of solar cells of  claim 2  wherein:
 the thermally conductive metal sheet includes a sheet of aluminum or copper or an alloy thereof; or 
 the thermally conductive metal sheet has a thickness of at least about 2 mils (0.002 inch); or 
 the thermally conductive metal sheet includes a sheet of aluminum or copper or an alloy thereof having a thickness of at least about 2 mils (0.002 inch). 
 
     
     
         4 . The laminated module of solar cells of  claim 2  wherein the thermally conductive metal sheet comprises a honeycomb, a perforated laminate, a structural member, or a combination thereof. 
     
     
         5 . The laminated module of solar cells of  claim 1  wherein:
 said melt flowable thermally conductive rear sheet has a thermal conductivity in a range of about 0.5-4.0 Watt per meter ° K; or 
 said melt flowable thermally conductive rear sheet has a thermal conductivity of up to about 20 Watt per meter ° K. 
 
     
     
         6 . The laminated module of solar cells of  claim 1  wherein said top layer, or said rear sheet, or both, comprise:
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C., or 
 a molecularly flexible thermoplastic adhesive having a glass transition temperature of less than about 0° C., or 
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C. and having a glass transition temperature of less than about 0° C.; or 
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C. and having more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C., or 
 a molecularly flexible thermoplastic adhesive having a glass transition temperature of less than about 0° C. and having more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C., or 
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C. and having a glass transition temperature of less than about 0° C. and having more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C.; or 
 any combination of the foregoing. 
 
     
     
         7 . The laminated module of solar cells of  claim 1  wherein the laminated module including the top layer and the rear sheet:
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C.; or 
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C. without cross-linking chemical curing; or 
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C. and has more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in a range between about 80° C. and about 200° C.; or 
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C. without cross-linking chemical curing and has more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C.; or 
 any combination of the foregoing. 
 
     
     
         8 . The laminated module of solar cells of  claim 1  wherein:
 said top layer includes: a polyvinylidene fluoride (PVDF), or a polyvinyl fluoride (PVF), or a copolymer thereof, or an ethylene vinyl acetate (EVA), or a modified PVDF, or a fluorinated polymer, or a laminate of any or all of the foregoing; or 
 said thermally conductive rear sheet includes: an EVA, or a PVF, or a PVDF, including thermally conductive particles so as to be thermally conductive; or 
 said top layer includes: a PVDF, or a PVF, or a copolymer thereof, or an EVA, or a modified PVDF, or a fluorinated polymer, or a laminate of any or all of the foregoing; and said thermally conductive rear sheet includes: an EVA, or a PVF, or a PVDF, including thermally conductive particles so as to be thermally conductive. 
 
     
     
         9 . The laminated module of solar cells of  claim 8  wherein: the thermally conductive particles include: alumina, zinc oxide, another thermally conductive electrically insulating material, or a combination thereof. 
     
     
         10 . The laminated module of solar cells of  claim 1  further comprising:
 a glass layer on an exposed front surface of said optically transparent top layer; or 
 a melt flowable optically transparent fluorinated polymer front layer on an exposed front surface of said optically transparent top layer; or 
 a thermally conductive layer on an exposed rear surface of said melt flowable rear sheet; or 
 an ultraviolet resistant melt flowable layer on an exposed rear surface of said melt flowable rear sheet; or 
 any combination of the foregoing. 
 
     
     
         11 . The laminated module of solar cells of  claim 1  wherein:
 said top layer is not as thick as is said rear sheet; or 
 said top layer is at least as thick as are said solar cells; or 
 said top layer is not as thick as is said rear sheet and is at least as thick as are said solar cells. 
 
     
     
         12 . The laminated module of solar cells of  claim 1  wherein said plurality of electrical connections comprise:
 a first pattern of melt flowable electrically conductive thermoplastic adhesive between said top layer and the front surfaces of said plurality of solar cells and a second pattern of melt flowable electrically conductive thermoplastic adhesive between said rear sheet and the back surfaces of said plurality of solar cells, wherein said first and second patterns of melt flowable electrically conductive thermoplastic adhesive melt flow to each other to provide the electrical connections of the solar cells; or 
 interconnection members comprising solderable metal strips soldered to metalized contacts of said plurality of solar cells; or 
 interconnection members comprising metal strips each having on opposing broad surfaces thereof a plurality of areas comprising melt flowable electrically conductive thermoplastic adhesive covering between about ten percent and 100 percent of the area of said metal strip and melt flowable electrically insulating thermoplastic adhesive substantially covering the remaining area of said metal strip. 
 
     
     
         13 . The laminated module of solar cells of  claim 1  wherein said laminated module of solar cells comprises a laminated solar cell panel. 
     
     
         14 . A laminated module of solar cells having front and back surfaces comprising:
 a plurality of solar cells having front and back surfaces to which electrical connection is to be made;   a top layer of an optically transparent electrically insulating material adjacent to and having adhesion to the front surfaces of solar cells,   whereby light may pass through said optically transparent top layer to impinge upon the front surfaces of said plurality of solar cells;   a thermally conductive rear sheet comprising a thermally conductive metal sheet and a melt flowed melt flowable thermally conductive and electrically insulating thermoplastic adhesive material layer adjacent to and having adhesion to the back surfaces of solar cells, said thermally conductive rear sheet having a thermal conductivity of at least 0.5 Watt per meter ° K;   a plurality of electrical connections, each electrical connection being between the front surface of one of said plurality of solar cells and the back surface of another of said plurality of solar cells,   whereby ones of said plurality of solar cells are electrically connected in series; and   said top layer, said thermally conductive rear sheet and said plurality of solar cells being melt flow laminated with at least the thermally conductive thermoplastic adhesive material layer of said rear sheet melt flow laminating to said plurality of solar cells;   said top layer adhering to the front surfaces of said plurality of solar cells and said melt flowed thermally conductive rear sheet adhering to the back surfaces of said plurality of solar cells;   whereby heat from said plurality of solar cells can be transferred via said thermally conductive rear sheet.   
     
     
         15 . The laminated module of solar cells of  claim 14  wherein:
 the thermally conductive metal sheet includes a sheet of aluminum or copper or an alloy thereof; or 
 the thermally conductive metal sheet has a thickness of at least about 2 mils (0.002 inch); or 
 the thermally conductive metal sheet includes a sheet of aluminum or copper or an alloy thereof having a thickness of at least about 2 mils (0.002 inch). 
 
     
     
         16 . The laminated module of solar cells of  claim 15  wherein the thermally conductive metal sheet comprises a honeycomb, a perforated laminate, a structural member, or a combination thereof. 
     
     
         17 . The laminated module of solar cells of  claim 14  wherein:
 said melt flowable thermally conductive rear sheet has a thermal conductivity in a range of about 0.5-4.0 Watt per meter ° K; or 
 said melt flowable thermally conductive rear sheet has a thermal conductivity of up to about 20 Watt per meter ° K. 
 
     
     
         18 . The laminated module of solar cells of  claim 14  wherein said top layer, or said rear sheet, or both, comprise:
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C., or 
 a molecularly flexible thermoplastic adhesive having a glass transition temperature of less than about 0° C., or 
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C. and having a glass transition temperature of less than about 0° C.; or 
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C. and having more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C., or 
 a molecularly flexible thermoplastic adhesive having a glass transition temperature of less than about 0° C. and having more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C., or 
 a molecularly flexible thermoplastic adhesive having a melt flow temperature in the range between about 80° C. and about 200° C. and having a glass transition temperature of less than about 0° C. and having more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C.; or 
 any combination of the foregoing. 
 
     
     
         19 . The laminated module of solar cells of  claim 14  wherein the laminated module including the top layer and the rear sheet:
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C.; or 
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C. without cross-linking chemical curing; or 
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C. and has more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in a range between about 80° C. and about 200° C.; or 
 exhibits a flexural modulus at about 60° C. that is at least fifty percent of the flexural modulus exhibited at about 20° C. without cross-linking chemical curing and has more than about ten percent (10%) molecular crystallites that flow at melt flow temperatures in the range between about 80° C. and about 200° C.; or 
 any combination of the foregoing. 
 
     
     
         20 . The laminated module of solar cells of  claim 14  wherein:
 said top layer includes: a polyvinylidene fluoride (PVDF), or a polyvinyl fluoride (PVF), or a copolymer thereof, or an ethylene vinyl acetate (EVA), or a modified PVDF, or a fluorinated polymer, or a laminate of any or all of the foregoing; or 
 said thermally conductive rear sheet includes: an EVA, or a PVF, or a PVDF, including thermally conductive particles so as to be thermally conductive; or 
 said top layer includes: a PVDF, or a PVF, or a copolymer thereof, or an EVA, or a modified PVDF, or a fluorinated polymer, or a laminate of any or all of the foregoing; and said thermally conductive rear sheet includes: an EVA, or a PVF, or a PVDF, including thermally conductive particles so as to be thermally conductive. 
 
     
     
         21 . The laminated module of solar cells of  claim 20  wherein: the thermally conductive particles include: alumina, zinc oxide, another thermally conductive electrically insulating material, or a combination thereof. 
     
     
         22 . The laminated module of solar cells of  claim 14  further comprising:
 a glass layer on an exposed front surface of said optically transparent top layer; or 
 a melt flowable optically transparent fluorinated polymer front layer on an exposed front surface of said optically transparent top layer; or 
 a thermally conductive layer on an exposed rear surface of said melt flowable rear sheet; or 
 an ultraviolet resistant melt flowable layer on an exposed rear surface of said melt flowable rear sheet; or 
 any combination of the foregoing. 
 
     
     
         23 . The laminated module of solar cells of  claim 14  wherein:
 said top layer is not as thick as is said rear sheet; or 
 said top layer is at least as thick as are said solar cells; or 
 said top layer is not as thick as is said rear sheet and is at least as thick as are said solar cells. 
 
     
     
         24 . The laminated module of solar cells of  claim 14  wherein said plurality of electrical connections comprise:
 a first pattern of melt flowable electrically conductive thermoplastic adhesive between said top layer and the front surfaces of said plurality of solar cells and a second pattern of melt flowable electrically conductive thermoplastic adhesive between said rear sheet and the back surfaces of said plurality of solar cells, wherein said first and second patterns of melt flowable electrically conductive thermoplastic adhesive melt flow to each other to provide the electrical connections of the solar cells; or 
 interconnection members comprising solderable metal strips soldered to metalized contacts of said plurality of solar cells; or 
 interconnection members comprising metal strips each having on opposing broad surfaces thereof a plurality of areas comprising melt flowable electrically conductive thermoplastic adhesive covering between about ten percent and 100 percent of the area of said metal strip and melt flowable electrically insulating thermoplastic adhesive substantially covering the remaining area of said metal strip. 
 
     
     
         25 . The laminated module of solar cells of  claim 14  wherein said laminated module of solar cells comprises a laminated solar cell panel.