Film bilayers of a photovoltaic module

thermoplastic film bilayers of a photovoltaic module, comprising two layers of which one layer forms the encapsulant (22) and the other layer forms the "backsheet" (26), the encapsulantebackseet assembly (22, 26) thicker than 100 um (micron), wherein: a) the encapsulant (22) comprises a layer comprising: - from 0% to 100% of one or more polyolefins containing a selected polyethylene between an ethylene-alpha-olefin whose density is between 0.865 and 0.91 (ASTM D 1505) or an ethylene (meth) acrylates anhydride; - from 0% to 100% of a grafted polyamide polymer comprising a polyolefin backbone, representing 50% to 95% by weight of polymer grafted polyamide comprising a residue of at least one unsaturated monomer (X) and at least one polyamide graft, representing 5% to 50% by mass of said polymer grafted polyamide, in which: - the polyamide graft is attached to the polyolefin backbone by radical unsaturated monomer (X) comprising a function capable of reacting by a condensation reaction with a polyamide having at least an amine end and / or at least one carboxylic acid end, - the radical unsaturated monomer (X) is attached to the trunk by grafting or copolymerization. - the polyolefin backbone and polyamide graft are selected so that said polymer grafted polyamide has a temperature of higher fluidity or equal to 75 ° C and not exceeding 160 ° C, defining the liquidus temperature as the highest temperature between the melting temperatures and glass transition temperatures of the polyamide and graft polyolefin backbone; b) the "backsheet" (26) comprises a layer formed of a grafted polyamide polymer comprising a polyolefin backbone, representing 50% to 95% by weight of polymer grafted polyamide comprising a residue of at least one unsaturated monomer (X) and at least one polyamide graft, representing 5% to 50% by mass of said polymer grafted polyamide, in which: - the polyamide graft is attached to the polyolefin backbone by radical monomer unsaturated (X) comprising a function capable of reacting by a condensation reaction with a polyamide having at least one amine end and / or at least one carboxylic acid end, - the radical of the unsaturated monomer (X) is attached to the trunk by grafting or copolymerization, - the polyolefin backbone and polyamide graft are selected so that said polymer grafted polyamide has a temperature greater than 160 ° fluidity defined as the liquidus temperature temp eratura higher among the melting temperatures and glass transition temperatures of the polyamide and graft polyolefin backbone.