Sealing material sheet for solar-cell module and solar-cell module using the same

Abstract

To provide a sealing material sheet for a solar-cell module that has high productivity without performing crosslinking processing, and has a high tensile shear adhesion force at normal temperature at a high level in addition to heat resistance and molding characteristics. A sealing material sheet is a multi-layer sheet using a polyethylene-based resin as a base resin, a core layer 11 has a density of 0.880 g/cm3 to 0.930 g/cm3 and a melting point of 70° C. or higher, a skin layer 12 has a density of 0.880 g/cm3 to 0.900 g/cm3 and a melting point of 90° C. or lower and contains a silane-modified polyethylene-based resin, a weight average molecular weight of the silane-modified polyethylene-based resin contained in the skin layer 12 in terms of polystyrene is 70000 to 120000, and a polymerized silane amount of the skin layer 12 in the whole resin component is 300 ppm to 2000 ppm.

1 . A sealing material sheet for a solar-cell module,
 the sealing material sheet being a multi-layer sheet using a polyethylene-based resin as a base resin and including a core layer and a skin layer disposed on both outermost surfaces, wherein the core layer has a density of 0.880 g/cm 3  to 0.930 g/cm 3  and a melting point of 70° C. or higher,   the skin layer has a density of 0.880 g/cm 3  to 0.900 g/cm 3  and a melting point of 90° C. or lower, and   the skin layer contains a silane-modified polyethylene-based resin, a weight average molecular weight of the silane-modified polyethylene-based resin contained in the skin layer in terms of polystyrene being 70000 to 120000, a polymerized silane amount of the skin layer in the whole resin component being 300 ppm to 2000 ppm.   
     
     
         2 . The sealing material sheet according to  claim 1 , wherein the weight average molecular weight of the silane-modified polyethylene-based resin contained in the skin layer in terms of polystyrene is 90000 to 120000. 
     
     
         3 . The sealing material sheet according to  claim 1 , wherein melting points of the core layer and the skin layer are both 70° C. to 80° C. 
     
     
         4 . A solar-cell module obtained by sequentially laminating a transparent front substrate, a sealing material of a light receiving surface side, a solar cell element, a sealing material of a non-light receiving surface side, and a rear-surface protecting substrate, the sealing material of the light receiving surface side and the sealing material of the non-light receiving surface side being the sealing material sheet according to  claim 1 . 
     
     
         5 . The solar-cell module according to  claim 4 , wherein both the transparent front substrate and the rear-surface protecting substrate are a protecting substrate made of glass. 
     
     
         6 . The solar-cell module according to  claim 5 , wherein the solar-cell module is a frameless module having no protecting frame that surrounds a circumference of a side surface of a module laminate interposed between the protecting substrates made of glass to maintain a shape of the module laminate. 
     
     
         7 . The solar-cell module according to  claim 4 , wherein, in a surface of the solar cell element, convex portions formed by a part of the surface protruding in a line-shaped manner or a dot-shaped manner exist, the convex portions being buried inside the sealing material sheet laminated on the surface, and
 a thickness of the convex portion is 50% to 90% of a thickness of the sealing material sheet laminated on the surface of the solar cell element.