Abstract: A fuel cell stack comprising a fuel inlet and an oxidant inlet for allowing the supply of a fuel and an oxidant to the fuel cell stack, respectively, and a fuel outlet and an oxidant outlet for allowing the removal of an anode exhaust and a cathode exhaust from the fuel cell stack, respectively, wherein the fuel outlet is fluidly connected to a high frequency purge valve.

Abstract: In a device for humidifying a gas flow, an atomized liquid is combined with a gas flow in a spray chamber, and passed through a generally U-shaped gas flow passage having a first generally vertical part 3 through which the atomized liquid and gas passes to a lower part 4. From there, the gas passes generally vertically upwardly to an outlet 9. The lower part of the passage incorporates an opening 6 to a water separator 7. The opening 6 is closable by a float device 10, or includes a flow restricting control valve 13.

Abstract: In a device for humidifying a gas flow, an atomized liquid is combined with a gas flow in a spray chamber, and passed through a generally U-shaped gas flow passage having a first generally vertical part 3 through which the atomized liquid and gas passes to a lower part 4. From there, the gas passes generally vertically upwardly to an outlet 9. The lower part of the passage incorporates an opening 6 to a water separator 7. The opening 6 is closable by a float device 10, or includes a flow restricting control valve 13.

Abstract: A fuel cell system comprising a fuel cell stack, a fuel recirculation line provided with a jet pump and a valve controlled by a control unit based on the anode-cathode pressure differential such that the valve is closed to reduce or stop fuel supply when the anode-cathode pressure differential reaches a predetermined value, and opened again to circulate more fuel through the jet pump when the pressure differential is below a predetermined value, to create a pulsed fuel supply that improves the fuel recirculation at low loads and ensures adequate water removal from the anode flow field channels.

Abstract: In a device for humidifying a gas flow, an atomized liquid is combined with a gas flow in a spray chamber, and passed through a generally U-shaped gas flow passage having a first generally vertical part 3 through which the atomized liquid and gas passes to a lower part 4. From there, the gas passes generally vertically upwardly to an outlet 9. The lower part of the passage incorporates an opening 6 to a water separator 7. The opening 6 is closable by a float device 10, or includes a flow restricting control valve 13.

Abstract: A method of operating a fuel cell system having a fuel cell stack and a humidifier is disclosed. The method includes directing at least a portion of the reactant gas through the reactant chamber of the humidifier, directing at least a portion of the exhaust gas through the exhaust chamber of the humidifier, determining the first pressure drop of the exhaust gas directed through the exhaust chamber, determining the first pressure drop limit of the exhaust gas directed through the exhaust chamber, and bypassing the remainder portion of the exhaust gas from the exhaust gas outlet around the exhaust chamber through the exhaust bypass passageway so that the first pressure drop does not exceed the determined first pressure drop limit.

Abstract: A fuel cell stack comprising a fuel inlet and an oxidant inlet for allowing the supply of a fuel and an oxidant to the fuel cell stack, respectively, and a fuel outlet and an oxidant outlet for allowing the removal of an anode exhaust and a cathode exhaust from the fuel cell stack, respectively, wherein the fuel outlet is fluidly connected to a high frequency purge valve.

Abstract: A fuel cell stack is provided having a plurality of fuel cells, each including a membrane electrode assembly interposed between anode and cathode flow field plates that form anode and cathode channels, respectively. An accumulating device is positioned downstream of the fuel cell stack. A purge control device is positioned downstream of the accumulating device operable in a first state to allow fluid communication between the anode and cathode channels, and in a second state to isolate an oxidant outlet from the accumulating device. Some embodiments include a purge control device between the anode channels and the accumulating device. A method of operation of the fuel cell stack includes selectively purging fluids from the fuel cell stack into the accumulating device at a first time and selectively purging fluids from the accumulating device at a second time, subsequent to the first time.

Abstract: An apparatus for recirculating a reactant fluid stream of a fuel cell system, and electric power generation systems comprising the apparatus, are disclosed. The apparatus comprises (1) a common suction chamber fluidly connected to a suction inlet configured to receive a recirculated flow from the exhaust stream of the fuel cell stack, (2) a low-flow nozzle positioned in the common suction chamber and fluidly connected to a low-flow motive inlet configured to receive a first motive flow from a reactant source of the fuel cell stack, (3) a low-flow diffuser fluidly connected to a discharge outlet configured to provide the inlet stream to the fuel cell stack, (4) a high-flow nozzle positioned in the common suction chamber and fluidly connected to a high-flow motive inlet configured to receive the first motive flow from the reactant source, and (5) a high-flow diffuser fluidly connected to the discharge outlet.

Abstract: Methods and apparatus for fuel release mitigation including enclosing a fuel cell stack (12) within an enclosure (20), supplying oxidant to the enclosure, circulating the oxidant within the enclosure to mix with any fuel present in the enclosure, withdrawing circulated oxidant from the enclosure; and supplying at least a portion of the circulated oxidant withdrawn from the enclosure to the stack as the cathode inlet stream.

Abstract: A fuel cell system comprising a fuel cell stack, a fuel recirculation line provided with a jet pump and a valve controlled by a control unit based on the anode-cathode pressure differential such that the valve is closed to reduce or stop fuel supply when the anode-cathode pressure differential reaches a predetermined value, and opened again to circulate more fuel through the jet pump when the pressure differential is below a predetermined value, to create a pulsed fuel supply that improves the fuel recirculation at low loads and ensures adequate water removal from the anode flow field channels.

Abstract: An electrochemical system is provided, the electrochemical system comprising a fuel cell stack, the fuel cell stack comprising at least one fuel cell, each fuel cell having at least one membrane electrode assembly interposed between an anode flow field plate and a cathode flow field plate, each membrane electrode assembly including an ion exchange membrane interposed between an anode electrode layer and a cathode electrode layer, wherein at least a portion of at least one of the anode electrode layers of the fuel cells is in fluid communication with an accumulating device. The accumulating device is operable to accumulate and dispense at least one of hydrogen, oxygen, and nitrogen. A method of ceasing operation of the electrochemical system is also disclosed.

Abstract: A system and method for implementing a fuel cell shutdown process are disclosed. Briefly described, one embodiment comprises establishing an oxidant recirculation path from a portion of the cathode flow path upon initiation of the fuel cell shutdown process, wherein the oxidant is recirculated during an oxygen depletion phase to substantially deplete oxygen residing therein to form a substantially oxygen-free fluid; and establishing an anode purge path from a portion of the cathode flow path and the anode flow path by means of a diverter valve, wherein the anode purge path is established upon completion of the oxygen depletion phase, and wherein the substantially oxygen-free fluid is transferred to the anode flow path to substantially purge out the fuel therein during a hydrogen purge phase.

Abstract: A fuel cell system and associated method allows for continuous operation of the fuel cell system with fuel recirculation, without the necessity for periodic purging. A portion of the anode exhaust is not recirculated but is continuously bled from the anode exhaust line. Preferably, less than 5% by volume of the anode exhaust is allowed to bleed continuously from the anode exhaust. The bleed line may be connected to a catalytic reactor which combusts the unused fuel. The cathode exhaust may be used as the oxidant for the catalytic reactor. The flow of exhaust to the catalytic reactor may be controlled to ensure that the concentration of hydrogen in the catalytic reactor is no higher than 50% of the lower limit of inflammability for hydrogen.

Abstract: An electric power generation system has a multiple jet ejector assembly for recirculating an exhaust stream. The system includes a fuel cell stack having a reactant stream inlet, a reactant stream outlet and at least one fuel cell. A pressurized reactant supply provides a reactant to the multiple jet ejector assembly. The multiple jet ejector assembly includes two motive flow inlets, one suction inlet, fluidly connected to the reactant stream outlet to receive a recirculated flow from the fuel cell stack, and one discharge outlet, fluidly connected to the reactant stream inlet to provide an inlet stream to the fuel cell stack. A pressure regulator is interposed between the pressurized reactant supply and the two motive flow inlets of the multiple jet ejector assembly. A first solenoid valve is interposed between the first motive flow inlet and the regulator. A second solenoid valve is interposed between the second motive flow inlet and the regulator.

Abstract: A method and apparatus for humidifying a gas flow includes means for atomizing a liquid into a gas feed line and means for heating the liquid. The atomizing means is provided in a spray chamber, with a heat-exchanger region for at least partially evaporating the liquid being arranged adjacent to the spray chamber. The heat-exchanger region has a multiplicity of flow passages for gas flows which are to be humidified, which flow passages are at least partially delimited by heat-exchanger surfaces for condensing and evaporating the liquid.

Abstract: A fuel cell system and associated method allows for continuous operation of the fuel cell system with fuel recirculation, without the necessity for periodic purging. A portion of the anode exhaust is not recirculated but is continuously bled from the anode exhaust line. Preferably, less than 5% by volume of the anode exhaust is allowed to bleed continuously from the anode exhaust. The bleed line may be connected to a catalytic reactor which combusts the unused fuel. The cathode exhaust may be used as the oxidant for the catalytic reactor. The flow of exhaust to the catalytic reactor may be controlled to ensure that the concentration of hydrogen in the catalytic reactor is no higher than 50% of the lower limit of inflammability for hydrogen.

Abstract: A method and apparatus for humidifying a gas flow includes means for atomizing a liquid into a gas feed line and means for heating the liquid. The atomizing means is provided in a spray chamber, with a heat-exchanger region for at least partially evaporating the liquid being arranged adjacent to the spray chamber. The heat-exchanger region has a multiplicity of flow passages for gas flows which are to be humidified, which flow passages are at least partially delimited by heat-exchanger surfaces for condensing and evaporating the liquid.

Abstract: A device is provided for filling a tank with a combustible medium from storage container. Supply means are disposed on the side of the storage container and receiving means are disposed on the side of the tank for introducing the medium into the tank. The supply means and the receiving means include closing means. The device further includes potential equalization means for equalizing an electrical potential between the storage container and the tank. The potential equalization means are arranged on the supply means or on the receiving means so that when the supply means move towards the receiving means, the potential equalization means can be forced into electrical contact with the housing of the tank. When the supply means subsequently come even closer to the chassis, the potential equalization means unlocks the closing means disposed on the supply means and/or the receiving means.

Abstract: A storage tank for a medium has a first volume provided for containing the gaseous medium and a second volume provided for at least receiving the liquid medium. A heater for heating the medium and inlet and outlet means for the medium are provided. The first volume is inside a first tank and the second volume is inside a second tank. The second tank is in fluid connection with said first tank via at least one fluid conduit and said second vessel is surrounded by said first vessel. The storage tank can store hydrogen for a fuel cell operated vehicle.