Ballard Power Systems Corporation

Gerard Francis McLean

Jeremy Lindstrom

Nedjib Djilali

Christopher E J Reid

Walter Roberto M&eacute;rida Donis

A separator plate for use in a fuel cell stack has a fuel gas flow field adjacent one surface and an oxidant gas flow field adjacent the other surface. The fuel cells in the stack are proton exchange membrane fuel cells having undulate membrane electrode assemblies. The flowpaths of the flow fields comprise parallel flow channels that extend longitudinally and interconnected at their ends to the separator plates. The couplings for the oxidant gas flow channels are offset from those for the fuel flow channels. The interconnecting couplings may be formed by stamping, machining or molding the separator plate.

Fuel cell separator plate providing interconnection of reactant gas flowpaths in undulate layer fuel cell stacks

An improved structure for a proton exchange membrane fuel cell stack is disclosed. The proton exchange membrane fuel cell stack comprising a membrane electrode assembly layer having a first surface and a second surface wherein a fuel gas flow field comprising at least one fuel gas flowpath is adjacent the first surface and an oxidant gas flow field comprising at least one oxidant gas flowpath is adjacent the second surface, the flowpaths having parallel transversely spaced and longitudinally extending flow channels interconnected in the vicinity of the ends of the flow channels to form the flowpaths. The membrane electrode assembly layer being provided, on both the first and second surfaces, with an array of spaced flow channel couplings, each coupling interconnecting at least two adjacent flow channels on the same surface of the assembly to form flowpaths for each of a fuel gas and an oxidant gas on respective surfaces of the assembly, wherein the couplings for the oxidant gas flow channels are transversely offset from the couplings for the fuel gas flow channels and wherein the membrane electrode assembly layer is undulate.

Membrane electrode assembly providing interconnection of reactant gas flowpaths in undulate layer fuel cell stacks

Corrugated flow field plates for use in fuel cells typically comprise a plurality of parallel open-faced fluid flow channels for the fuel cell reactants. Complex flow paths, such as serpentine flow paths, may be created in such corrugated flow field plates by incorporating channel couplings within the plate or by attaching coupling subassemblies to the plate. The plates are particularly suitable for use in solid polymer electrolyte fuel cells.

Corrugated flow field plate assembly for a fuel cell

A proton exchange membrane (PEM)-type fuel cell is formed from layered undulate MEA structures and separator plates alternating with each other in the stack dimension so that each layered MEA structure is disposed between and attached to an associated pair of separator plates so as to form at least one discrete conduit on each side of each layered MEA structure through which conduit reactant gas may be circulated. Each layered MEA structure is formed from proton exchange membrane material sandwiched between a pair of spaced-apart current collectors with electro-catalyst particles between the membrane material and each current collector so that the membrane material and electro-catalyst particles fill the space between the current collectors, forming together with the current collectors a layered MEA structure. Each separator plate is formed from a non-conductive substrate overlaid on each surface by a selected pattern of conductive paths, paths on one side of the substrate being connected by vias to paths on the other side of the substrate, the paths being attached to the current collectors of the layered MEA structures on either side of the separator plate.

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Victoria, Canada

Gerard Francis McLean