Patent ID: 6773841
Filing Date: 2004-08-10
Classification: H01M,Y02E

Abstract:
In a PEM fuel cell comprising a plurality of cells arranged in a stack, each cell comprising an anode exposed to a first reactant, a cathode exposed to a second reactant and a membrane-electrolyte interjacent said anode and cathode, at least one electrically conductive, bipolar plate separating one of said cells from the next, said bipolar plate comprising (a) an electrically conductive, active region having a first face confronting the anode of one cell in said stack, a second face confronting the cathode of the next adjacent cell in said stack, and an internal cooling passage for circulating coolant through said plate behind said faces, and (b) an electrically conductive inactive region bordering said active region, said inactive region having a surface defining an opening in said inactive region that in part defines a manifold adapted to supply coolant to said passage or remove coolant from said passage, the improvement comprising an adherent, non-conductive coating on said surface to reduce the flow of shunt currents through said coolant in said manifold.