Back-contact back-sheet for a photovoltaic module comprising back-contact cells, said back-contact back-sheet comprising: a substrate having an outer surface exposed toward the air-side of said photovoltaic module and an inner surface opposite said outer surface and exposed toward the inside of said photovoltaic module, a layer of an electrically conductive material adapted to be formed as a connecting circuit to the electrodes of said solar cells and directly adherent to said inner surface of said substrate, said layer of conductive material being firmly fixed to said inner surface of said substrate, wherein said substrate comprises: an insulating portion comprising a lower surface facing the air-side of the photovoltaic module and substantially coincident with said outer surface of said substrate and an upper surface opposite said lower surface, a primer layer firmly fixed to said upper surface of said insulating portion, said primer layer comprising a lower surface facing said upper surface of said insulating portion and an upper surface opposite said lower surface of said primer layer and substantially coincident with said inner surface of said substrate, characterized in that: said primer layer comprises a thermo-adhesive material, wherein said conductive material layer is fixed to said primer layer by means of heat so that no adhesives are present between said conductive material layer and said primer layer. a substrate having an outer surface exposed toward the air-side of said photovoltaic module and an inner surface opposite said outer surface and exposed toward the inside of said photovoltaic module, a layer of an electrically conductive material adapted to be formed as a connecting circuit to the electrodes of said solar cells and directly adherent to said inner surface of said substrate, said layer of conductive material being firmly fixed to said inner surface of said substrate, wherein said substrate comprises: an insulating portion comprising a lower surface facing the air-side of the photovoltaic module and substantially coincident with said outer surface of said substrate and an upper surface opposite said lower surface, a primer layer firmly fixed to said upper surface of said insulating portion, said primer layer comprising a lower surface facing said upper surface of said insulating portion and an upper surface opposite said lower surface of said primer layer and substantially coincident with said inner surface of said substrate, an insulating portion comprising a lower surface facing the air-side of the photovoltaic module and substantially coincident with said outer surface of said substrate and an upper surface opposite said lower surface, a primer layer firmly fixed to said upper surface of said insulating portion, said primer layer comprising a lower surface facing said upper surface of said insulating portion and an upper surface opposite said lower surface of said primer layer and substantially coincident with said inner surface of said substrate, characterized in that: said primer layer comprises a thermo-adhesive material, wherein said conductive material layer is fixed to said primer layer by means of heat so that no adhesives are present between said conductive material layer and said primer layer. said primer layer comprises a thermo-adhesive material, wherein said conductive material layer is fixed to said primer layer by means of heat so that no adhesives are present between said conductive material layer and said primer layer.