Method of fabricating an integral gas seal for fuel cell gas distribution assemblies

A method of producing a bipolar assembly for use in a fuel cell stack wherein contiguous plates are provided to distribute oxidant and reactant gas respectively to adjacent cells of said stack comprising the steps of:

• providing at least two electrically conductive distribution plates having a foraminous structure suitable for transporting gas therethrough;
• each of said plates being provided with at least one channel substantially along an axis thereof to allow for the substantially unrestricted flow of gas along said axis;
• disposing a film of thermally sensitive, insulative material between said plates;
• simultaneously applying a pressure of at least 200 psi and a temperature in the range of from about 500-700 degrees Fahrenheit to effect essentially complete redistribution of the film into the interfacial pores of said plates about the interfacial plane defined between said plates;
• said film of insulative material being configured and dimensioned to impregnate the interfacial pores and form a substantially gas--impermeable barrier at the interface between said plates;
• cooling the plates and insulative material while maintaining the pressure thereon so as to ensure the lamina remain bonded together upon release of the pressure;
• said plates being bonded so that they are in contact with one another in electroconductive registry
• whereby said bipolar assembly is suitable for series type electrical arrangement within said fuel cell stack and effectively isolates reactant and oxidant gasses on opposite sides of the interface between said conductive distribution plates of said bipolar assembly during operation of said fuel cell stack.