Flow fields for fuel cells
View Patent ↗An improved proton exchange membrane fuel cell assembly and fuel cell stack assembly are provided for the economical and efficient production of electricity. The present invention comprises improved flow fields, which provide improved and more efficient mass transport of the reactants in the fuel cell and the fuel cell stack assembly. The improved flow fields comprise three-dimensional open-cell foamed metals that are preferably plated with gold. The improved reactant supply system comprises an improved distribution frame to house fuel cells wherein the reactants are directly connected to the improved flow fields.
1. A gas flow field for use in a fuel cell comprising a three-dimensional, open-cell, foamed structure including at least one corrugation;
wherein the three-dimensional, open-cell, foamed structure comprises at least one material chosen from the group consisting of carbon filament, stainless steel, derivatives of stainless steel, epitaxial substrates, nickel, nickel alloys, gold, gold alloys, copper, copper alloys, thermoplastics, and iridium; and
wherein the three-dimensional, open-cell, foamed structure is microplated with gold, iridium, copper, or silver.
2. The gas flow field of claim 1 , wherein the three-dimensional, open-cell, foamed structure proximate to each of at least one of the corrugations defines a microchannel.
3. The gas flow field of claim 1 , wherein the three-dimensional, open-cell, foamed structure has a plurality of corrugations.
4. The gas flow field of claim 3 , wherein the corrugations each have a pitch and a run, the pitch for each corrugation being at least equal to two-thirds of the run for that corrugation.
5. The gas flow field of claim 1 , wherein the open cells of the three-dimensional, open-cell, foamed structure are five-sided substantially geometrically shaped orifices.
6. A method of preparing a gas flow field comprising the steps of:
applying metal to a particulate thermoplastic resinous material;
adding cobalt to the metal;
removing the particulate resinous structure to produce a three-dimensional, open-cell, foamed structure; and
corrugating the three-dimensional, open-cell, foamed structure to define a plurality of microchannels.
7. The method of preparing a gas flow field according to claim 6 further comprising the additional step of microplating the deformed three-dimensional, open-cell, foamed structure.
8. A gas flow field made according to the method of claim 6 .
9. The method of claim 6 , further comprising causing the open cells of the three-dimensional, open-cell, foamed structure to have five-sided substantially geometrically shaped orifices.