Fuel cell assembly
The invention relates to fuel cell assemblies, and in particular to improvements relating to sealing of such assemblies, embodiments of which include a fuel cell assembly ( 200 ) comprising a membrane electrode assembly ( 104 ), a cathode separator plate ( 208 ) having a series of corrugations extending, and providing air flow paths, between first and second opposing edges of the plate, a gasket ( 105 ) providing a fluid seal around a peripheral edge of the membrane electrode assembly ( 104 ) between the separator plate ( 208 ) and the membrane electrode assembly ( 104 ) and a metal shim ( 107 ) disposed between the gasket ( 105 ) and the separator plate ( 208 ) over the peripheral edge of the membrane electrode assembly ( 104 ).
1. A fuel cell assembly comprising:
a membrane electrode assembly having a sub-gasket region;
a cathode separator plate comprising a series of corrugations extending, and providing air flow paths, between first and second opposing edges of the cathode separator plate, each corrugation comprising a first crest on a first face of the cathode separator plate and a second crest on a second face of the cathode separator plate;
the cathode separator plate further comprising a metal shim element disposed on the second face of the cathode separator plate in contact with at least a portion of the second crests of the series of corrugations,
wherein the metal shim element is provided as an integral part of the separator plate, the metal shim comprising first and second strips longitudinally extending transverse the corrugations of the cathode separator plate and extending along respective first and second opposing edges of the plate, the first and second strips each attached to the series of corrugations by a fold from a portion of the second crest of a corrugation forming a third edge of the cathode separator plate;
wherein the sub-gasket region of the membrane electrode assembly mates with the metal shim element to provide a fluid seal around a peripheral edge of the membrane electrode assembly;
wherein the first and second strips of the metal shim do not extend beyond the ends of the air flow paths of the series of corrugations.
2. The fuel cell assembly of claim 1 wherein each of the first and second strips of the metal shim element is further attached to the series of corrugations by a bonded region disposed on a portion of the second crest of a corrugation forming a fourth edge of the cathode separator plate, the fourth edge being opposite the third edge.
3. The fuel cell assembly of claim 1 or claim 2 wherein the metal shim element has a larger thickness than at least a portion of the series of corrugations.
4. The fuel cell assembly of claim 2 wherein the bonded region is formed from spot welding or adhesive bonding between the metal shim element and the portion of the second crest forming a fourth edge of the cathode separator plate.