Solar cells which include the use of certain poly(vinyl butyral)/film bilayer encapsulant layers with a low blocking tendency and a simplified process to produce thereof

Abstract

The present invention provides a solar cell laminate comprising a preformed bi-layer sheet having a poly(vinyl butyral) sub-layer.

1 . A solar cell laminate comprising (i) a solar cell layer comprising one or a plurality of electronically interconnected solar cells and having a light-receiving side and a back side, and (ii) at least one preformed bi-layer sheet comprising a first sub-layer comprising a poly(vinyl butyral) and a second sub-layer comprising a metal or polymeric film. 
     
     
         2 . The solar cell laminate of  claim 1 , wherein said metal film is an aluminum foil. 
     
     
         3 . The solar cell laminate of  claim 1 , wherein said polymeric film comprises a polymeric composition selected from the group consisting of poly(ethylene terephthalate), polycarbonate, polypropylene, polyethylene, polypropylene, cyclic polyolefins, norbornene polymers, polystyrene, syndiotactic polystyrene, styrene-acrylate copolymers, acrylonitrile-styrene copolymers, poly(ethylene naphthalate), polyethersulfone, polysulfone, nylons, poly(urethanes), acrylics, cellulose acetates, cellulose triacetates, cellophane, vinyl chloride polymers, polyvinylidene chloride, vinylidene chloride copolymers, fluoropolymers, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, and ethylene-tetrafluoroethylene copolymers. 
     
     
         4 . The solar cell laminate of  claim 1 , wherein said one or a plurality of solar cells are selected from the group consisting of multi-crystalline solar cells, thin film solar cells, compound semiconductor solar cells, and amorphous silicon solar cells. 
     
     
         5 . The solar cell laminate of  claim 1 , wherein said at least one preformed bi-layer sheet is laminated to the light-receiving side of said solar cell layer and serves as a front-sheet encapsulant layer, and wherein the second sub-layer of said at least one preformed bi-layer sheet comprises said polymeric film. 
     
     
         6 . The solar cell laminate of  claim 5 , further comprising a back-sheet encapsulant layer that is laminated to the back side of said solar cell layer and comprises a polymeric composition selected from the group consisting of poly(vinyl butyral), ionomers, ethylene vinyl acetate, acoustic poly(vinyl acetal), acoustic poly(vinyl butyral), thermoplastic polyurethane, polyvinylchloride, metallocene-catalyzed linear low density polyethylenes, polyolefin block elastomers, ethylene acrylate ester copolymers, acid copolymers, silicone elastomers and epoxy resins. 
     
     
         7 . The solar cell laminate of  claim 6 , wherein said back-sheet encapsulant layer is formed of a second preformed bi-layer sheet. 
     
     
         8 . The solar cell laminate of  claim 1 , wherein said at least one preformed bi-layer sheet is laminated to the back side of said solar cell layer and serves as a back-sheet encapsulant layer. 
     
     
         9 . The solar cell laminate of  claim 8 , further comprising a front-sheet encapsulant layer that is laminated to the light-receiving side of said solar cell layer and comprises a polymeric composition selected from the group consisting of poly(vinyl butyral), ionomers, ethylene vinyl acetate, acoustic poly(vinyl acetal), acoustic poly(vinyl butyral), thermoplastic polyurethane, polyvinylchloride, metallocene-catalyzed linear low density polyethylenes, polyolefin block elastomers, ethylene acrylate ester copolymers, acid copolymers, silicone elastomers and epoxy resins. 
     
     
         10 . The solar cell laminate of  claim 6 , wherein the first sub-layer of said at least one preformed bi-layer sheet is in direct contact with and adhered to said solar cell layer. 
     
     
         11 . The solar cell laminate of  claim 10 , wherein the second sub-layer of said at least one preformed bi-layer sheet has at least one side hard coated. 
     
     
         12 . The solar cell laminate of  claim 10 , further comprising a back-sheet laminated to said back-sheet encapsulant layer opposite from said solar cell layer. 
     
     
         13 . The solar cell laminate of  claim 10 , further comprising an incident layer and a second front-sheet encapsulant layer, wherein said incident layer is bonded to said preformed bi-layer sheet with said second front-sheet encapsulant layer in between. 
     
     
         14 . The solar cell laminate of  claim 9 , wherein the first sub-layer of said at least one preformed bi-layer sheet is in direct contact with and adhered to said solar cell layer. 
     
     
         15 . The solar cell laminate of  claim 14 , wherein the second sub-layer of said at least one preformed bi-layer sheet has at least one side hard coated. 
     
     
         16 . The solar cell laminate of  claim 14 , further comprising an incident layer laminated to said front-sheet encapsulant layer opposite from said solar cell layer. 
     
     
         17 . The solar cell laminate of  claim 14 , further comprising a back-sheet and a second back-sheet encapsulant layer, wherein said back-sheet is bonded to said at least one preformed bi-layer sheet with said second back-sheet encapsulant layer in between. 
     
     
         18 . The solar cell laminate of  claim 6 , further comprising a second front-sheet encapsulant layer, wherein the second sub-layer of said at least one preformed bi-layer sheet is in direct contact with and adhered to said second front-sheet encapsulant layer, which is in turn in direct contact with and adhered to the light-receiving side of said solar cell layer. 
     
     
         19 . The solar cell laminate of  claim 18 , further comprising an incident layer laminated to said at least one preformed bi-layer sheet at the first sub-layer side and a back layer laminated to said back-sheet encapsulant layer opposite from said solar cell layer. 
     
     
         20 . The solar cell laminate of  claim 9 , further comprising a second back-sheet encapsulant layer, wherein the second sub-layer of said at least one preformed bi-layer sheet is in direct contact with and adhered to said second back-sheet encapsulant layer, which is in turn in direct contact with and adhered to the back side of said solar cell layer. 
     
     
         21 . The solar cell laminate of  claim 20 , further comprising an incident layer laminated to said front-sheet encapsulant layer opposite from said solar cell layer and a back-sheet laminated to said at least one preformed bi-layer sheet at the first sub-layer side. 
     
     
         22 . A process of manufacturing a solar cell laminate comprising: (i) providing an assembly comprising, from top to bottom, a front-sheet encapsulant layer, a solar cell layer comprising one or a plurality of electronically interconnected solar cells, and a back-sheet encapsulant layer, and (ii) laminating the assembly to form the solar cell module, wherein at least one of the two encapsulant layers is formed of a preformed bi-layer sheet comprising a first sub-layer comprising a poly(vinyl butyral) and a second sub-layer comprising a metal or polymeric film. 
     
     
         23 . The process of  claim 22 , wherein said front-sheet encapsulant layer is formed of said preformed bi-layer sheet with its first sub-layer in direct contact with said solar cell layer, and wherein said assembly in step (i) further comprises a back-sheet placed next to said back-sheet encapsulant layer opposite from said solar cell layer. 
     
     
         24 . The process of  claim 23 , wherein said assembly in step (i) further comprises a second front-sheet encapsulant layer and an incident layer, wherein said incident layer is placed next to said second front-sheet encapsulant layer, which in turn is in direct contact with the second sub-layer of said preformed bi-layer sheet. 
     
     
         25 . The process of  claim 22 , wherein said back-sheet encapsulant layer is formed of said preformed bi-layer sheet with its first sub-layer in direct contact with said solar cell layer, and wherein said assembly in step (i) further comprises an incident layer placed next to said front-sheet encapsulant layer opposite from said solar cell layer. 
     
     
         26 . The process of  claim 25 , wherein said assembly in step (i) further comprises a second back-sheet encapsulant layer and a back-sheet, wherein said back-sheet is placed next to said second back-sheet encapsulant layer, which in turn is in direct contact with the second sub-layer of said preformed bi-layer sheet. 
     
     
         27 . The process of  claim 22 , wherein said front-sheet encapsulant layer is formed of said preformed bi-layer sheet with its second sub-layer in a closer proximity to said solar cell layer; wherein said assembly in step (i) further comprises an incident layer, a second front-sheet encapsulant layer, and a back-sheet; wherein said incident layer is placed next to the first sub-layer of said preformed bi-layer sheet, which in turn has its second sub-layer in direct contact with said second front-sheet encapsulant layer, and which in turn is in direct contact with said solar cell layer; and wherein said back-sheet is placed next to said back-sheet encapsulant layer opposite from said solar cell layer. 
     
     
         28 . The process of  claim 22 , wherein said back-sheet encapsulant layer is formed of said preformed bi-layer sheet with its second sub-layer in a closer proximity to said solar cell layer; wherein said assembly in step (i) further comprises an incident layer, a second back-sheet encapsulant layer, and a back-sheet; wherein said incident layer is placed next to said front-sheet encapsulant layer opposite from said solar cell layer; and wherein said back-sheet is placed next to the first sub-layer of said preformed bi-layer sheet, which in turn has its second sub-layer in direct contact with said second back-sheet encapsulant layer, and which in turn is in direct contact with said solar cell layer. 
     
     
         29 . The process of  claim 22 , wherein the step (ii) of lamination is conducted by subjecting the assembly to heat. 
     
     
         30 . The process of  claim 29 , wherein the step (ii) of lamination further comprises subjecting the assembly to pressure. 
     
     
         31 . The process of  claim 29 , wherein the step (ii) of lamination further comprises subjecting the assembly to vacuum.