Bipolar plate, characterized in that it comprises first and second conductive sheets (51, 52), and in which: - an inlet manifold and an outlet manifold of coolant, and an inlet manifold and an outlet manifold of a reactant are made through the first and second conductive sheets; - coolant flow channels are made between the conductive sheets (51, 52) and are in communication with the coolant inlet and outlet manifolds; - an outer face of the first conductive sheet comprising: - first ribs delimiting reactant flow channels, these reactant flow channels being in communication with the reactant inlet and outlet manifolds: - a second rib extending on the side of the reactant flow channels, a gasket extending at least partially on said second rib; - third ribs extending between one of said first ribs and the second rib, an alternation of third ribs and of indentations being formed in an intermediate zone extending between this first rib and the second rib, said first and second sheets (51, 52) being in contact at the indentations, respective passages being formed under the third ribs to place one of said coolant manifolds in communication with coolant flow channels, said third ribs having a height greater than that of the first ribs, the third ribs each having in their middle portion a cross section comprising junctions between their top and an adjacent indentation, said junctions having a portion set back relative to a straight line connecting their top to the closest contact between the first and second sheets. - an inlet manifold and an outlet manifold of coolant, and an inlet manifold and an outlet manifold of a reactant are made through the first and second conductive sheets; - coolant flow channels are made between the conductive sheets (51, 52) and are in communication with the coolant inlet and outlet manifolds; - an outer face of the first conductive sheet comprising: - first ribs delimiting reactant flow channels, these reactant flow channels being in communication with the reactant inlet and outlet manifolds: - a second rib extending on the side of the reactant flow channels, a gasket extending at least partially on said second rib; - third ribs extending between one of said first ribs and the second rib, an alternation of third ribs and of indentations being formed in an intermediate zone extending between this first rib and the second rib, said first and second sheets (51, 52) being in contact at the indentations, respective passages being formed under the third ribs to place one of said coolant manifolds in communication with coolant flow channels, said third ribs having a height greater than that of the first ribs, the third ribs each having in their middle portion a cross section comprising junctions between their top and an adjacent indentation, said junctions having a portion set back relative to a straight line connecting their top to the closest contact between the first and second sheets. - first ribs delimiting reactant flow channels, these reactant flow channels being in communication with the reactant inlet and outlet manifolds: - a second rib extending on the side of the reactant flow channels, a gasket extending at least partially on said second rib; - third ribs extending between one of said first ribs and the second rib, an alternation of third ribs and of indentations being formed in an intermediate zone extending between this first rib and the second rib, said first and second sheets (51, 52) being in contact at the indentations, respective passages being formed under the third ribs to place one of said coolant manifolds in communication with coolant flow channels, said third ribs having a height greater than that of the first ribs, the third ribs each having in their middle portion a cross section comprising junctions between their top and an adjacent indentation, said junctions having a portion set back relative to a straight line connecting their top to the closest contact between the first and second sheets.