Ballard Power Systems Corporation

Peter Robert Gibb

Henry H Voss

Russell H Barton

Boguslaw M Wozniczka

Joel A Ronne

Nicholas J Fletcher

David P Wilkinson

Emerson Richard Gallagher

Eric G Pow

Neil V Davis

Wolfgang Schlosser

Kemal Ozgur

David Kau-Kee Yip

In an improved electrochemical fuel cell assembly, a reactant flow path extends substantially linearly across the electrochemically active area of an electrode. The electrode has an in-plane nonuniform structure in its electrochemically active area as the active area is traversed in the direction of the substantially linear reactant flow path. Embodiments in which the structure of the fuel cell electrode varies substantially symmetrically along the reactant flow path are particularly preferred in fuel cells in which the flow direction of a reactant is periodically reversed.

Electrochemical fuel cell with an electrode having an in-plane nonuniform structure

A flow field plate assembly for an electrochemical fuel cell comprises two flow field plates, each of which has channels formed on an inner surface of the plate. The plates are alignable with and engage each other such that their cooperating inner surfaces form at least one inner coolant fluid channel. The coolant channel has an essentially constant cross-sectional perimeter along its length, which is defined by the perimeters of the channels of the two plates and their difference in width at the cooperating plate surfaces. Additionally, a flow field plate assembly, which comprises a corrugated flow field plate and a staggered flow field plate, is structurally stronger under compressive load during the fuel cell operation.

Flow field plate assembly for an electrochemical fuel cell

A compression mechanism comprises a planar spring sheet having a plurality of openings rendering the spring sheet resilient. An electrochemical fuel cell assembly with resilient compression mechanism includes a plurality of fuel cell assemblies interposed between first and second endplates. The mechanism for securing the fuel cell assemblies in their assembled, compressed state includes at least one resilient compression spring sheet extending between first and second endplates.

Compression mechanism for an electrochemical fuel cell assembly

An improved membrane electrode assembly (&ldquo;MEA&rdquo;) comprises coextensive ion exchange membrane and electrode layers and a resilient fluid impermeable integral seal comprising a sealant material impregnated into the porous electrode layers in the sealing regions. The integral seal preferably circumscribes the electrochemically active area of the MEA. The integral seal preferably also extends laterally beyond the edge of the MEA. An integral seal may also be provided around any openings, such as external manifold openings formed outside the MEA. Preferably, the uncured sealant material is a flow processable elastomer applied using an injection molding process. In preferred embodiments the seal has a plurality of spaced, parallel raised ribs with cross-ribs extending therebetween at spaced intervals. The raised ribs and cross-ribs provide compartmentalized seals that provide improved protection against fluid leaks.

Membrane electrode assembly for an electrochemical fuel cell

A volume efficient, layered manifold assembly is disclosed for an array of one or more internally manifolded fuel cell stacks. The assembly comprises a stack of substantially planar layers in which each pair of adjacent layers defines a fluid distribution chamber or plenum. Appropriate passages connect each chamber to the internal manifolds of the fuel cell stacks and to various external fluid ports for supply or exhaust of fuel, oxidant, or coolant streams. Passages for at least one fluid penetrate the layers defining the distribution chamber for another fluid. Valving can be incorporated directly in the manifold assembly and used to periodically reverse the direction of fluid flow through internal manifolds of the fuel cell stacks.

Volume effecient layered manifold assembly for electrochemical fuel cell

An electrochemical fuel cell stack comprises a first end plate, a second end plate, and fuel cell assemblies interposed between the first and second end plates. The stack further includes a compression assembly comprising a compression mechanism and a restraining mechanism. The compression mechanism urges the first end plate towards the second end plate applying an internal compressive force to the fuel cell assemblies, even as the thickness of the fuel cell assemblies changes. The restraining mechanism prevents movement of the first end plate away from the second end plate by preventing deflection of the compression mechanism, which may occur, for example, when internal fluid pressure is increased.

Compression assembly for an electrochemical fuel cell stack

An improved membrane electrode assembly ('MEA') comprises coextensive ion exchange membrane and electrode layers and a resilient fluid impermeable integral seal made by impregnating a sealing material into the porous electrode layers in the sealing regions. The integral seal preferably circumscribes the electrochemically active area of the MEA. In addition, the integral seal preferably extends laterally beyond the edge of the MEA, enveloping the peripheral region including the side edge of the MEA. The uncured sealant material is preferably a flow processable elastomer that is applied to the MEA using a vacuum injection molding process. In preferred embodiments, the seal has a plurality of spaced, parallel raised ribs with cross-ribs extending therebetween at spaced intervals. The parallel raised ribs and cross-ribs provide compartmentalized seals that provide improved protection against fluid leaks.

Membrane electrode assembly for an electrochemical fuel cell and a

An electrochemical fuel cell stack includes a plurality of fuel cell assemblies interposed between a pair of end plate assemblies. The mechanism for securing the stack in its compressed, assembled state includes at least one compression band which circumscribes the end plate assemblies and interposed fuel cell assemblies of the stack. At least one of the end plate assemblies is sufficiently thin so as to deflect under the compressive force if the at least one end plate assembly is supported only at a peripheral edge portion thereof. Preferably, at least one of the end plate assemblies comprises a resilient member which cooperates with each compression band to urge the first end plate assembly toward the second end plate assembly, thereby applying compressive force to the fuel cell assemblies to promote sealing and electrical contact between the layers forming the fuel cell stack.

Electrochemical fuel cell stack with compression bands

An electrochemical fuel cell stack includes a plurality of fuel cell assemblies interposed between a pair of end plate assemblies. The mechanism for securing the stack in its compressed, assembled state includes at least one compression band which circumscribes the end plate assemblies and interposed fuel cell assemblies of the stack. Preferably, at least one of the end plate assemblies comprises a resilient member which cooperates with each compression band to urge the first end plate assembly toward the second end plate assembly, thereby applying compressive force to the fuel cell assemblies to promote sealing and electrical contact between the layers forming the fuel cell stack.

An electrochemical fuel cell stack has a first end plate, a second end plate, and fuel cell assemblies interposed therebetween. Each fuel cell assembly includes a membrane electrode assembly having at least one manifold header opening formed in the assembly for directing at least one of a fluid fuel stream, a fluid oxidant stream and a fluid coolant stream through the assembly. A tie rod extends within the opening and through each of the first and second end plates. Fastening means are disposed at opposite ends of the tie rod. Compressive means are interposed between at least one of the fastening means and at least one of the first and second end plates. In operation, the fastening means and the compressive means urge the first end plate toward the second end plate, thereby applying compressive force to the fuel cell assemblies.

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Coquitlam, Canada

Peter Robert Gibb