Abstract: The present invention discloses a stamped bridge member that defines a flow path between a header and a flow field on a fuel cell plate. The bridge member provides a support surface on which a seal can be positioned to seal the plate against adjacent plates or MEAs. The fuel cell plates can be stamped plates with two surfaces each having flow fields thereon. The flow fields maintain a fluid flowing between a supply header and a return header on a single surface of the plate. The ends of the flow fields can taper relative to the supply and return apertures to provide for a desired flow distribution through the flow field.

Abstract: A fuel cell stack that includes straight cathode flow channels and straight anode flow channels through a seal area between bipolar plates in the stack. The fuel cell stack includes a seal that extends around the active area of the stack and between the stack headers and the active area. At the locations where the cathode flow channels extend through a seal area to the cathode input header and the cathode outlet header, and the anode flow channels extend through a seal area to the anode input header and the anode output header, the diffusion media layer on one side of the membrane is extended to provide the seal load. Alternately, shims can be used to carry the seal load.

Abstract: A fuel cell in a fuel cell stack that provides a transition from nested bipolar plates in the active region of the stack to non-nested bipolar plates in the inactive regions of the stack without giving up the reduced stack thickness provided by the nested plates or changing the size of the flow channels. Particularly, the diffusion media layers in the fuel cells are removed in the inactive regions where the bipolar plates are non-nested so that the volume necessary to maintain the size of the flow channels is provided without the need to increase the distance between adjacent MEAs. A thin shim can be provided between the membranes and the plates in the inactive regions to support the membrane where the diffusion media layer has been removed to prevent the membrane from intruding into the flow channels and blocking the reactive flow.

Abstract: A device and method are provided to allow the flowpaths in a fuel cell stack to be reconfigured dependent on reactant gas throughput in order to maintain appropriate pressure drop, sufficient velocities, and reactant concentrations of each cell of a fuel cell stack.

Abstract: Clearance gaps in the inactive feed regions of a fuel cell stack are controlled by non-bonded, non-nested bipolar plates to provide reactant flow uniformity and pressure within fuel cells and fuel cell stacks utilizing nested bipolar plates in the active feed regions and non-nested bipolar plates in the inactive feed regions.

Abstract: A PEM fuel cell includes a cathode plate for directing a first fluid along a surface thereof. An anode plate directs a second fluid along a surface thereof. An MEA is oriented in a first direction. The MEA includes an anode face opposing the anode plate and a cathode face opposing the cathode plate. A plate margin includes first and second header apertures oriented in a second direction perpendicular to the first direction. A first seal is disposed between the anode plate and the MEA. The first seal defines a first fluid communication path between the first header aperture and the anode plate. A second seal is disposed between the cathode plate and the MEA. The second seal defines a second fluid communication path between the second header aperture and the cathode plate. The first and second seals allow the first and second fluid to flow through respective passages thereon in a direction parallel the first direction.

Abstract: A bipolar plate assembly for use in a PEM fuel cell having an anode plate and a cathode plate together to define flow fields on the exposed faces thereof and a coolant volume therebetween. Each of the flow fields have a transverse inlet leg in fluid communication with the inlet header, a serpentine flow field extending from the transverse inlet leg and a transverse exhaust leg in fluid communication with the exhaust header. The plates further define a tortuous coolant flow path in the coolant volume.

Abstract: A fuel cell in a fuel cell stack that provides a transition from nested bipolar plates in the active region of the stack to non-nested bipolar plates in the inactive regions of the stack without giving up the reduced stack thickness provided by the nested plates or changing the size of the flow channels. Particularly, the diffusion media layers in the fuel cells are removed in the inactive regions where the bipolar plates are non-nested so that the volume necessary to maintain the size of the flow channels is provided without the need to increase the distance between adjacent MEAs. A thin shim can be provided between the membranes and the plates in the inactive regions to support the membrane where the diffusion media layer has been removed to prevent the membrane from intruding into the flow channels and blocking the reactive flow.

Abstract: An electro-chemical fuel cell stack has a plurality of fuel cells arranged in a stacked configuration to form a fuel cell assembly. The fuel cell assembly is interposed between at least one spacer plate and first and second end plates. The first and second end plates are held in a fixed spaced relation so that the first and second end plates impart a compressive force on the fuel cell assembly. The spacer plates can be used to provide a fuel cell stack of a predetermined length. The fuel cell stack can be made by compressing the fuel cell stack with a predetermined compressive load or by compressing the fuel cell stack a predetermined distance and then securing the first and second end plates in a fixed spaced relation.

Abstract: An alignment system and method for assembling a fuel cell stack. Components of the fuel cell stack have internal alignment features and are aligned to a predetermined orientation during assembly. The system and method allow fuel cell stacks to be assembled within high tolerance levels while improving access to each component during assembly. Additionally, the system and method can provide additional rigidity to a fuel cell stack.

Abstract: A diffusion media for use in a PEM fuel cell which includes a relieved edge region relative to the interior region of the diffusion media. The outer perimeter or portion of the diffusion media that will interface with a sealing gasket is pre-compressed. The pre-compressed diffusion media lowers the compression stress on the MEA at the gasket interfaces, enabling a more uniform compression on the entirety of the MEA surfaces during the build, compression, and later operation of a fuel cell stack.

Abstract: A seal configuration is provided for a fuel cell stack, including a first bipolar plate and a second bipolar plate, each disposed on opposite sides of a membrane electrode assembly. The seal configuration includes a first sub-gasket adhered to a recess region of the first bipolar plate and a second sub-gasket adhered to a recess region of the second bipolar plate wherein the first and second sub-gaskets are disposed on opposite sides of the membrane electrode assembly. A seal member is disposed in the recessed regions of the first and second bipolar plates and between the first and second sub-gaskets. The seal configuration minimizes the size of the bypass regions around the seal perimeter and provide better control of the positions of all components during assembly of the fuel cell stack. The approach also reduces sensitivity to ambient relative humidity variations and reduces manufacturing costs by eliminating the need for humidity control in the production area.

Abstract: The present invention discloses a stamped bridge member that defines a flow path between a header and a flow field on a fuel cell plate. The bridge member provides a support surface on which a seal can be positioned to seal the plate against adjacent plates or MEAs. The fuel cell plates can be stamped plates with two surfaces each having flow fields thereon. The flow fields maintain a fluid flowing between a supply header and a return header on a single surface of the plate. The ends of the flow fields can taper relative to the supply and return apertures to provide for a desired flow distribution through the flow field.

Abstract: A separator plate for a fuel cell is provided including a first support element and a series of second support elements extending from a first surface of the plate. A series of apertures are disposed between the first support element and the series of second support elements for communicating a reactant gas therethrough for delivery to a flow field of the separator plate.

Abstract: The present invention isolates the fluid streams flowing into and out of a fuel cell stack from the terminal plates so that the fluid streams and terminal plates do not come into contact with one another. The prevention of the fluid streams from contacting the terminal plate eliminates corrosion concerns associated with the terminal plate. The present invention accomplishes this isolation through the use of headers having fluid passageways therein that route the fluid streams in and/or out of the fuel cell stack while preventing contact between the fluid streams and the terminal plate.

Abstract: A flow field geometry formed in a separator plate of a fuel cell includes a plurality of straight inlet legs including a first lateral inlet leg laterally offset from a first inlet leg and a dividing junction associated with each of the plurality of straight inlet legs. The dividing junction divides a straight inlet leg into a plurality of branched legs. A number of a first set of branched legs associated with the first lateral inlet leg is greater than a number of a set of branched legs associated with the first inlet leg.

Abstract: A bipolar plate for use in a fuel cell stack includes a first plate having a first coolant face with a first set of coolant channels formed therein. A second plate has a second coolant face with a second set of coolant channels formed therein. The first and second coolant faces are adjacent to one another to intermittently cross-link the first and second sets of coolant channels over a region of the first and second coolant faces.

Abstract: A device and method are provided to allow the flowpaths in a fuel cell stack to be reconfigured dependent on reactant gas throughput in order to maintain appropriate pressure drop, sufficient velocities, and reactant concentrations of each cell of a fuel cell stack.

Abstract: A sensor for monitoring the lambda of a component of a reactant feed stream flowing through a fuel cell stack. The sensor comprises one or more fuel cells that are sensitive to a change in lambda of a specific component of a reactant feed stream flowing through the fuel cell. The sensitivity of the fuel cell causes a voltage produced by the lambda sensing fuel cell to vary in response to variation in the lambda of the specific component. The variation of the voltage output can be modeled and/or compared to empirical data to correlate the voltage output to the lambda of the specific component. Based on the lambda of the specific component, the operation of the fuel cell stack can be optimized.

Abstract: A bipolar plate assembly for a PEM fuel cell having a serpentine flow field formed on one side and interdigitated flow field formed on the opposite side such that a single plate member are usable for as an anode current collector and a cathode current collector of adjacent fuel cells. The bipolar plate assembly further includes a staggered seal arrangement to direct gaseous reactant flow through the fuel cell such that the seal thickness maximized while the repeat distance between adjacent fuel cells is minimized.