Fuel cell membrane electrode assembly with sealing surfaces

Abstract

The present invention provides a gasketed fuel cell membrane electrode assembly comprising: a polymer electrolyte membrane; layers of anode and cathode catalyst; anode-side and cathode-side fluid transport layer; and anode-side and cathode-side gaskets; where the gaskets comprise an elastomeric gasket material which is impregnated into the outer edge portions of the respective fluid transport layer; and where at least a portion of the contact face of each gasket bears a raised-ridge microstructured contact pattern. The gasketed fuel cell membrane electrode assembly according to the present invention may additionally comprise a rigid, non-elastomeric anode-side and cathode-side shims positioned between at least a portion of the gasket and the polymer electrolyte membrane. The raised-ridge microstructured contact pattern preferably comprises ridges which meet at joining points, wherein no more than three ridges meet at any one joining point. Such raised-ridge microstructured contact patterns may be hexagonal patterns or degenerate hexagonal patterns. In another aspect, the present invention provides a method of making a gasketed fuel cell membrane electrode assembly by simultaneously binding together the parts of the MEA, impregnating uncured elastomeric gasket material into the outer edge portions of each fluid transport layer, and substantially curing the uncured elastomeric gasket material so as to form anode-side and cathode-side gaskets. In order to form a raised-ridge microstructured contact pattern on the contact face of each gasket, patterning plates bearing a negative relief of a raised-ridge microstructured contact pattern may be positioned between the press platens and the uncured elastomeric gasket material.