CPC H01L 31/0481 (2013.01) [H01L 31/049 (2014.12)] | 14 Claims |
1. A photovoltaic module comprising
(a) a front layer arranged on the sunlight facing side of the photovoltaic module wherein the front layer comprises at least 95 weight percent of a first polypropylene composition based on total weight of the front layer, wherein the first polypropylene composition comprises at least 95 weight percent of a random copolymer of propylene and a comonomer wherein the comonomer is ethylene or an alpha olefin of 4 to 12 carbon atoms, provided that if the comonomer is ethylene the ethylene is present in amounts of no greater than 7 weight percent based on total weight of the random copolymer, wherein the transmission of the front layer for light in the wavelength range of 350 nm to 1200 nm as determined according to ASTM D1003-13, is on average at least 65% as compared to a situation without the front layer,
(b) a sealing layer which at least partly encapsulates a plurality of photovoltaic cells by having a first portion of the sealing layer above the plurality of photovoltaic cells and a second portion of the sealing layer below the plurality of photovoltaic cells where each of the first portion and the second portion of the sealing layer are a monolayer,
wherein the scaling layer comprises a polyolefin elastomer composition comprising an ethylene-alpha-olefin copolymer wherein the amount of alpha olefin is less than 40 weight percent based on weight of the ethylene-alpha-olefin copolymer and wherein the sealing layer is characterized by a transmission of the sealing layer for light in the wavelength range of 350 nm to 1200 nm as determined according to ASTM D1003-13, is on average at least 65% as compared to a situation without the sealing layer, and
(c) a back layer, wherein the back layer comprises a first polypropylene layer comprising a second polypropylene composition comprising a polypropylene, wherein (i) the second polypropylene composition comprises a reinforcing filler, and/or (ii) the back layer further comprises a second polypropylene layer adjacent to the first polypropylene layer and a third polypropylene layer adjacent to the second polypropylene layer on a side opposite from the first polypropylene layer, wherein the second polypropylene layer is a polypropylene foam or a polypropylene honeycomb structure and wherein the back layer has a flexural stiffness in at least one direction of at least 5 Nm, wherein the flexural stiffness is measured according to ASTM D790M (Three point bending with span of 40 cm) and/or a flexural stiffness to weight/m2 ratio of at least 1.5 Nm3/kg, wherein the flexural stiffness is the lowest flexural stiffness the back layer and wherein the flexural stiffness is measured according to ASTM D790M (Three point bending with span of 40 cm) and wherein the weight/m2 is the weight (in kg) per square meter of the back layer,
wherein the first portion of the sealing layer is arranged between and in direct contact with the front layer and the plurality of photovoltaic cells and the second portion of the sealing layer is arranged between and in direct contact with the back layer and the plurality of photovoltaic cells.
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