Efficient fuel cell water transport plates
OwnerCarol A. Koch, Prakash Mallya +2inventors
InventorsCarol A. Koch, Prakash Mallya, Evgueni Rosenbaoum, Sriram Venkatasanthanam
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Abstract
A fuel cell separator or water transport plate is formed of graphite, carbon fibers and an inert thermosetting hydrophilic binder. The materials may be in powdered form, and plates, preferably channeled, are formed using heat and pressure. The hydrophilic properties of the plates may be improved by immersion in an oxidizing bath followed by water rinsing. The active materials included in the plate are substantially limited to graphite, carbon fibers and the binder, and no additional hydrophilic coatings, materials or any high temperature processes are involved.
Claims69
A method of forming a fuel cell separator or water transport plate comprising the steps of:
- mixing together the following materials in the indicated weight proportions:
- (a) about 50% to about 80% of conductive powder;
- (b) about 5% to about 20% of conductive fibers;
- (c) about 15% to about 30% of a electrochemically inert binder;
- and
- molding a plate from the foregoing mixture using heat and pressure sufficient to form a porous and hydrophilic plate.
10 A method as defined in claim 9 wherein the weight proportion of the finely divided graphite is about 60% to about 75%, the weight proportion of the carbon fibers is about 10% to about 15%, and the weight proportion of the electrochemically inert thermosetting binder is about 15% to about 25%.
A fuel cell separator or water transport plate comprising:
- a stiff ridged plate formed of about 50% to about 80% by weight of conductive powder, about 5% to about 20% by weight of conductive fibers, and about 15% to about 30% by weight of a electrochemically inert binder;
- said plate being porous and having a hydrophilic or wettable surface.
A method of forming a fuel cell separator or water transport plate comprising the steps of:
- mixing together the following materials in the indicated weight proportions:
- (a) about 50% to about 80% of conductive powder;
- (b) about 5% to about 20% of conductive fibers;
- (c) about 15% to about 30% of a powdered electrochemically inert binder;
- molding a water transport plate from the foregoing mixture using heat and pressure sufficient to form a porous plate with hydrophilic or wettable surface including through the pores thereof, and
- subjecting the plate to oxidation to increase the hydrophilic properties thereof.
48 A method as defined in claim 47 wherein the weight proportion of the finely divided graphite is about 60% to about 75%, the weight proportion of the carbon fibers is about 10% to about 15%, and the weight proportion of the electrochemically inert thermosetting binder is about 15% to about 25%.
A fuel cell separator or water transport plate comprising:
- a plate formed of 50% to 80% by weight of finely divided graphite, 5% to 20% of carbon fibers, and 15 to 30% of an electrochemically inert binder;
- said plate being porous and having a hydrophilic or wettable surfaces;
- the foregoing listed ingredients being the only ingredients affecting performance of the plate in a fuel cell assembly included in the plate.
58 A fuel cell separator or water transport plate as defined in claim 57 wherein the oxidation is performed by reacting with an oxidizing agent selected from the group consisting of sodium hypochlorite, sulfuric acid, chromic acid, potassium permanganate, nitric acid, peroxides, and selenium dioxide.
Dependencies are inferred from the claim text.