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AssigneeBallard Power Systems Inc.
InventorsDavid P. Wilkinson, Jean St.-Pierre, Joy A. Roberts, Stephen A. Campbell
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An improved method reduces fuel cell performance degradation of an electrode comprising porous components. Electrochemical solid polymer electrolyte fuel cells typically have present therein a liquid which expands upon freezing, such as, for example water. The presence of such a liquid within the pores of the electrode components may cause performance degradation of the liquid freezes. The present method comprises employing an impregnant within at least some of the pores of the electrode components. The impregnant inhibits the deterioration of porous fuel cell components caused by expansion of the liquid within the pores when the fuel cell components are subjected to a temperature below the freezing temperature of the liquid. Preferably the impregnant does not expand when changing phases from a liquid to a solid. The impregnant may comprise an organic fluid, an organic acid, an inorganic acid, a polymer or dispersion.
A method of reducing fuel cell performance degradation of an electrode comprising porous components, said electrode having present therein a liquid that expands upon freezing, said method comprising disposing an impregnant within at least some pores and micropores of said electrode components, whereby the presence of said impregnant in said pores and micropores reduces structural damage caused by freeze expansion of said liquid within said pores and micropores.
A method of impregnating a porous electrode component for reducing fuel cell performance degradation resulting from liquid freeze-expansion within pores of said component, said method comprising contacting said electrode component with an impregnant at a pressure below atmospheric pressure, until said impregnant is deposited within micropores of said electrode component.
A method of impregnating a porous electrode component for reducing fuel cell performance degradation resulting from liquid freeze-expansion within pores of said electrode, said method comprising contacting said electrode component with an impregnant at a pressure above atmospheric pressure, until said impregnant is deposited within micropores of said electrode component.
An electrochemical fuel cell with improved resistance to performance degradation of an electrode caused by liquid freeze-expansion within pores and micropores of porous components of said electrode, said fuel cell comprising:
Dependencies are inferred from the claim text.