Fuel cell assembly having long life characteristics
AssigneeUTC Power Corporation
InventorsRichard D. Breault, Robert R. Fredley
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Abstract
A fuel cell assembly (20) has a plurality of characteristics that extend the useful life of the assembly. In one example, flow field layers are non-porous and hydrophobic such that they have an acid absorption rate of less than about 0.10 mg/khr-cm2. An electrolyte retaining matrix has a reaction rate with phosphoric acid of less than about 0.010 mg/khr-cm2. Hydrophilic substrates associated with catalyst layers have an initial transferable phosphoric acid content of less than about 25 mg/cm2. A condensation zone provides an evaporative phosphoric acid loss rate that is less than about 0.17 mg/khr-cm2.
Claims18
A fuel cell assembly, comprising:
- a separator plate;
- a first flow field layer and a second flow field layer associated with the separator plate, the flow field layers having an acid absorption rate of less than about 0.10 mg/khr-cm2;
- an electrolyte retaining matrix having a reaction rate with phosphoric acid of less than about 0.010 mg/khr-cm2;
- a cathode catalyst layer;
- an anode catalyst layer;
- hydrophilic substrates associated with the catalyst layers, the hydrophilic substrates having an initial transferable phosphoric acid content of less than about 45 mg/cm2;
- and
- a condensation zone that provides an evaporative phosphoric acid loss rate of less than about 0.27 mg/khr-cm2.
A method of operating a phosphoric acid fuel cell assembly, comprising the steps of:
- maintaining an acid absorption rate of less than about 0.10 mg/khr-cm2;
- maintaining a reaction rate of an electrolyte matrix with phosphoric acid of less than about 0.010 mg/khr-cm2;
- providing hydrophilic substrates with an initial transferable phosphoric acid content of less than about 45 mg/cm2;
- and
- maintaining an evaporative phosphoric acid loss rate of less than about 0.27 mg/khr-cm2.
Dependencies are inferred from the claim text.