Abstract: A plate includes a working face and a header portion. The working face defines a plurality of reactant channels thereon. The header portion is disposed in a peripheral area of the plate and includes a plurality of flanges and a plurality of beads. The flanges are disposed on the header portion and define a plurality of apertures through the plate. Each flange defines a respective one of the apertures. At least one of the apertures is fluidly connected to the reactant channels. The plurality of beads is disposed on the working face. Each bead is disposed about a respective one of the apertures and thereby defines a respective one of the flanges. Each bead defines a shape consisting of bead-corners and bead-sides. Each bead has a sealing surface thereon. The sealing surface is configured to deflect when exposed to a contact pressure to thereby provide a substantially fluid-tight seal.

Abstract: A method for creating an oxygen depleted gas in a fuel cell system, including operating a fuel cell stack at a desired cathode stoichiometry at fuel cell system shutdown to displace a cathode exhaust gas with an oxygen depleted gas. The method further includes closing a cathode flow valve and turning off a compressor to stop the flow of cathode air.

Abstract: A method for manufacturing a bipolar plate includes the steps of: (1) providing sheet metal within a stamping press system; (2) stamping the sheet metal with a first die to define an interim flat land, a first interim sidewall, a second interim sidewall, and a first interim channel depth for a plurality of flow channels; and (3) stamping the sheet metal with a second die to widen the interim flat land in each flow channel in the plurality of flow channels forming a final flat land and to reduce each interim radii of each flow channel in the plurality of flow channels. The stamping press system may, but not necessarily, include a first press station having a first die set and a second press station having a second die set wherein the second press station is applied to the sheet metal after it has been formed by the first press station.

Abstract: A plate includes a working face and a header portion. The working face defines a plurality of reactant channels thereon. The header portion is disposed in a peripheral area of the plate and includes a plurality of flanges and a plurality of beads. The flanges are disposed on the header portion and define a plurality of apertures through the plate. Each flange defines a respective one of the apertures. At least one of the apertures is fluidly connected to the reactant channels. The plurality of beads is disposed on the working face. Each bead is disposed about a respective one of the apertures and thereby defines a respective one of the flanges. Each bead defines a shape consisting of bead-corners and bead-sides. Each bead has a sealing surface thereon. The sealing surface is configured to deflect when exposed to a contact pressure to thereby provide a substantially fluid-tight seal.

Abstract: A bipolar plate used in a fuel cell and a method of making a bipolar plate. The sheet is made generally from a stainless steel, and in a more preferable form from a ferritic stainless steel. In one configuration, a stamping or related metal forming tool operation will introduce a negative clearance as a way to move or otherwise reallocate a portion of the material making up the sheet into other portions as a way to reduce stretching, necking, thinning and related thickness deviations associated with the bends formed in the bipolar plate.

Abstract: A bipolar plate used in a fuel cell and a method of making a bipolar plate. The sheet is made generally from a stainless steel, and in a more preferable form from a ferritic stainless steel. In one configuration, a stamping or related metal forming tool operation will introduce a negative clearance as a way to move or otherwise reallocate a portion of the material making up the sheet into other portions as a way to reduce stretching, necking, thinning and related thickness deviations associated with the bends formed in the bipolar plate.

Abstract: A method for creating an oxygen depleted gas in a fuel cell system, including operating a fuel cell stack at a desired cathode stoichiometry at fuel cell system shutdown to displace a cathode exhaust gas with an oxygen depleted gas. The method further includes closing a cathode flow valve and turning off a compressor to stop the flow of cathode air.

Abstract: A system and method for controlling hydrogen gas flow to an anode side of a fuel cell stack using a pressure regulator in the event that an injector that normally injects the hydrogen gas into the fuel cell stack has failed in a stuck open position. During normal operation, the control of the injector is determined based on the pressure of an anode sub-system and the position of the pressure regulator is determined based on a supply pressure between the pressure regulator and the injector. If it is determined that the injector is stuck in an open position, then the position of the pressure regulator is controlled to the anode pressure instead of the supply pressure. If the pressure regulator is an electrical pressure regulator, then it is pulsed to mimic normal system operation. Alternately, another valve, such as a shut-off valve, can be employed to provide the flow pulsing.

Abstract: A system and method for controlling hydrogen gas flow to an anode side of a fuel cell stack using a pressure regulator in the event that an injector that normally injects the hydrogen gas into the fuel cell stack has failed in a stuck open position. During normal operation, the control of the injector is determined based on the pressure of an anode sub-system and the position of the pressure regulator is determined based on a supply pressure between the pressure regulator and the injector. If it is determined that the injector is stuck in an open position, then the position of the pressure regulator is controlled to the anode pressure instead of the supply pressure. If the pressure regulator is an electrical pressure regulator, then it is pulsed to mimic normal system operation. Alternately, another valve, such as a shut-off valve, can be employed to provide the flow pulsing.