Abstract: A fuel cell assembly for a solid polymer electrolyte fuel cell stack may employ a construction in which a plastic film frame is used to frame a catalyst coated membrane within. In one advantageous embodiment, the plastic film frame is adhesive coated on one side and laminated at its inner edge to one surface of the catalyst coated membrane and at its outer edge to the flow field plate on the opposite side. In another advantageous embodiment, the plastic film frame is laminated to sealing features incorporated in a transition region in the flow field plate.

Abstract: In solid polymer electrolyte fuel cell stacks, increasing the height of support features in the transition regions and/or increasing the depth of the transition regions improves the flow of reactants therein and thus improves the sharing of flow in the channels in the reactant flow fields. The support feature height and transition region depth are increased so as to be out of plane with respect to the landings and channels in the reactant flow fields. The invention is suitable for cells employing metal flow field plates or plates in which no adhesives are employed in the transition regions.

Abstract: Bipolar plate assemblies are disclosed in which the transition fuel channels are offset from the transition oxidant channels in the transition regions on the active sides of the plates. This configuration allows for a reduced pressure drop in the coolant flow in the transition regions on the inactive, coolant side of the plates and thereby improves coolant flow sharing. The assemblies are suitable for use in high power density solid polymer electrolyte fuel cell stacks.

Abstract: In solid polymer electrolyte fuel cell stacks, increasing the height of support features in the transition regions and/or increasing the depth of the transition regions improves the flow of reactants therein and thus improves the sharing of flow in the channels in the reactant flow fields. The support feature height and transition region depth are increased so as to be out of plane with respect to the landings and channels in the reactant flow fields. The invention is suitable for cells employing metal flow field plates or plates in which no adhesives are employed in the transition regions.

Abstract: A fuel cell assembly for a solid polymer electrolyte fuel cell stack may employ a construction in which a plastic film frame is used to frame a catalyst coated membrane within. In one advantageous embodiment, the plastic film frame is adhesive coated on one side and laminated at its inner edge to one surface of the catalyst coated membrane and at its outer edge to the flow field plate on the opposite side. In another advantageous embodiment, the plastic film frame is laminated to sealing features incorporated in a transition region in the flow field plate.

Abstract: The flow field plates in a bipolar plate assembly for a fuel cell can be both bonded and sealed appropriately using microencapsulated adhesives. This offers several advantages over using other adhesives which may have limited pot life and/or require lengthy curing periods at elevated temperature during which time the plates must be stably positioned and under compression.

Abstract: Alignment features and methods for their use are disclosed for purposes of aligning adjacent bipolar plates, and also optionally the membrane electrode assemblies as well as the plates making up the bipolar plates, during assembly of solid polymer electrolyte fuel cell stacks. The alignment features are located within common datum openings and advantageously can be in-plane with the bipolar plates. This provides for improved alignment and manufacturability.

Abstract: The pressure drop associated with the coolant flow in the coolant transition regions of a typical high power density, solid polymer electrolyte fuel cell stack can be significant. This pressure drop can be reduced by enlarging the height of the coolant ducts in this region of the associated flow field plate so that the ducts extend beyond the plane of the plate. The height change can be accommodated by offsetting the ducts in adjacent cells in the stack and by employing non planar MEAs in this region. By reducing the pressure drop, improved coolant flow sharing is obtained.

Abstract: Bipolar plate assemblies are disclosed in which the transition fuel channels are offset from the transition oxidant channels in the transition regions on the active sides of the plates. This configuration allows for a reduced pressure drop in the coolant flow in the transition regions on the inactive, coolant side of the plates and thereby improves coolant flow sharing. The assemblies are suitable for use in high power density solid polymer electrolyte fuel cell stacks.

Abstract: A plurality of flow field plate assemblies forms a fuel cell stack. Each flow field plate assembly has a first flow field plate positionable on an anode side of a membrane electrode assembly (MEA) of a first fuel cell, a second flow field plate positionable on a cathode side of an MEA of a second fuel cell, adjacent the first fuel cell. At least one back-feed channel is interposed between the first and second flow field plates. At least a portion of the back-feed channel or a reactant manifold opening formed by the first and second flow field plates has a geometry that forms regions of high and low capillary forces, promoting liquid migration toward regions substantially isolated from a flow of reactants, to prevent water collection and ice formation. The migrated liquid is purged during a purge of the fuel cell stack after operation.

Abstract: The flow field plates in a bipolar plate assembly for a fuel cell can be both bonded and sealed appropriately using microencapsulated adhesives. This offers several advantages over using other adhesives which may have limited pot life and/or require lengthy curing periods at elevated temperature during which time the plates must be stably positioned and under compression.

Abstract: The pressure drop associated with the coolant flow in the coolant transition regions of a typical high power density, solid polymer electrolyte fuel cell stack can be significant. This pressure drop can be reduced by enlarging the height of the coolant ducts in this region of the associated flow field plate so that the ducts extend beyond the plane of the plate. The height change can be accommodated by offsetting the ducts in adjacent cells in the stack and by employing non planar MEAs in this region. By reducing the pressure drop, improved coolant flow sharing is obtained.

Abstract: Systems and methods for transporting accumulated water in a fuel cell system are disclosed. Briefly described, in one aspect, a system comprises a fuel cell flow field plate with at least one channel disposed on a surface of the fuel cell flow field plate, and at least one water management fin residing on a wall of the channel such that when the accumulated water is transported along the channel the water management fin guides the accumulated water.

Abstract: A fuel cell separator having a first plate, the first plate including an active surface comprising a reactant flow field and a header fluidly connected thereto, an opposing non-active surface, and a header channel fluidly connected to the header, wherein the header further includes a recess directly fluidly connected to one end of the header channel, wherein the recess comprises a top perimeter and a side wall. In one embodiment, the header channel is formed on the active surface of the plate. In another embodiment, the header channel is formed on the non-active surface of the plate and the side wall of the header further comprises at least one fluid port fluidly connected to the end of the header channel.

Abstract: Systems and methods for transporting accumulated water in a fuel cell system are disclosed. Briefly described, in one aspect, a system comprises a fuel cell flow field plate with at least one channel disposed on a surface of the fuel cell flow field plate, and at least one water management fin residing on a wall of the channel such that when the accumulated water is transported along the channel the water management fin guides the accumulated water.

Abstract: A low compressive load seal for a solid polymer fuel cell employs two offset peripheral projections, one on each of the anode and cathode separator plates, for compressing a gasket. The design can achieve a seal against a given burst pressure with a lower load normal to the separator plates by creating significant compression parallel to the separator plates in the gap between the offset projections. The design allows for thinner fuel cell constructions while avoiding the issues that arise in prior art designs (e.g., stress on seal material and component crushing) if reasonable tolerances were allowed for variations in component thickness.

Abstract: An electrochemical fuel cell stack having staggered fuel and oxidant plenums is disclosed. This construction allows for reduced cell pitch without reducing plenum thickness and hence fluid flow.

Abstract: A fluid flow field plate for an electrochemical fuel cell that includes a planar body having a first surface, a second surface. More than one header opening extends between the first surface and the second surface to define a flowpath. At least one open flow field channel with an inlet port and an outlet port is provided in the first surface. Each outlet port is in fluid communication with one of the one header openings. At least one of the outlet port or the inlet port has a baffle extending into the flow path.

Abstract: A membrane electrode assembly with an improved integrated seal comprises an edge seal having an inboard pad attached to the edge of the electrodes, a flexible coupling adjacent the pad, and a sealing element adjacent the coupling. The sealing element is significantly thicker than the pad, and the flexible coupling isolates the pad from stress experienced in the sealing element. Thus, greater compression can be applied to the sealing element, thereby providing an improved and more reliable seal, without overly compressing and damaging the attached pad.

Abstract: A plurality of flow field plate assemblies forms a fuel cell stack. Each flow field plate assembly has a first flow field plate positionable on an anode side of a membrane electrode assembly (MEA) of a first fuel cell, a second flow field plate positionable on a cathode side of an MEA of a second fuel cell, adjacent the first fuel cell. At least one back-feed channel is interposed between the first and second flow field plates. At least a portion of the back-feed channel or a reactant manifold opening formed by the first and second flow field plates has a geometry that forms regions of high and low capillary forces, promoting liquid migration toward regions substantially isolated from a flow of reactants, to prevent water collection and ice formation. The migrated liquid being is purged during a purge of the fuel cell stack after operation.