Abstract: A fuel cell system capable of restraining temperature change in a fuel cell caused by a refrigerant. The fuel cell system has a refrigerant circulating system for circulating the refrigerant. The refrigerant circulating system has flow control means for restraining the inflow of the refrigerant, which has a predetermined difference in temperature from that of the fuel cell, into the fuel cell.

Abstract: A fuel cell system includes a fuel cell; a cathode inflow water amount determining portion that determines a cathode inflow water amount after activation of the fuel cell; an obtaining portion that obtains a pore total volume of the cathode side catalyst layer; an operating condition determining portion that determines, based on the determined cathode inflow water amount and the obtained pore total volume, an operating condition of the fuel cell that includes a current value of current that flows through the fuel cell and an upper limit value of a period of time for which the current flows, for bringing the cathode inflow water amount within a range that is equal to or less than the pore total volume; and an adjusting portion that adjusts the current value and the period of time for which current of the current value flows, such that the determined operating condition is realized.

Abstract: A fuel cell system includes a fuel cell, a cathode supply passage, a cathode discharging passage, an anode supply passage, an anode discharging passage, a pair of cathode shutoff units, an anode shutoff unit, an anode discharging unit, a discharged gas processing unit, and a control unit. The control unit releases the sealing of the cathode passage by the pair of cathode shutoff units, at the time of start-up of the fuel cell system, and releases the sealing of the anode passage by the anode discharging unit, thereby performing a purge process to allow discharge of the anode gas.

Abstract: A fuel cell system includes a fuel cell, anode gas pressure adjusting means that adjusts the pressure of an anode gas supplied to the fuel cell, and cathode gas pressure adjusting means that adjusts the pressure of a cathode gas supplied to the fuel cell. The system further includes pressure control means that sets the pressure of the anode gas that is supplied when starting the fuel cell higher than the pressure of the anode gas that is supplied during power generation in the fuel cell, and controls the anode gas pressure adjusting means and the cathode gas pressure adjusting means so that a cathode gas pressure increase is started in accordance with the start of an anode gas pressure increase when the pressure of the anode gas is increased to the set pressure.

Abstract: A fuel cell system of the present invention includes: a fuel cell (11) configured to generate electric power using a fuel gas and an oxidizing gas; an anode off gas channel (34) through which an anode off gas discharged from an anode (2a) of the fuel cell (11) flows; a gas-liquid separator (10) disposed on the anode off gas channel (34) to separate moisture from the anode off gas, and including a water reservoir (18) configured to store the separated moisture as water; a temperature detector (28) configured to detect a temperature of the water reservoir (18); and an operation allowing device (52) configured not to allow an operation of the fuel cell system in a case where the temperature detected by the temperature detector (28) is equal to or higher than a first threshold that is higher than a standard ambient temperature.

Abstract: A fuel battery system of the present invention includes: an alkaline fuel battery; a fuel supply device for supplying a fuel to an anode of the fuel battery; an oxidizing agent supply device for supplying an oxidizing agent to a cathode of the fuel battery; a liquid supply device which supplies a liquid to the cathode; a valve which switches between fluids to be supplied to the cathode; and a control device which controls the switching of the valve. The fuel battery system suppresses the neutralization of an anion-exchange electrolyte due to carbon dioxide in the air, by supplying the liquid from the liquid supply device to the cathode and making the cathode in the state of being immersed in the liquid when the fuel battery stops power generation.

Abstract: A method for operating a fuel cell stack where electrical energy from regenerative braking is used to operate system loads instead of using fuel cell stack power to conserve hydrogen. A fuel cell stack and an ultracapacitor are electrically coupled to a high voltage electrical bus. A by-pass line is provided around a blocking diode including a by-pass contactor. A stack contactor is provided to disconnect the fuel cell stack from the electrical bus. A stand-by mode request is made if the voltage at a node proximate to the blocking diode closest to the ultracapacitor is higher than the voltage at a node proximate to the blocking diode closest to the fuel cell stack. Steps are then made to electrically prepare the high voltage electrical bus. Then, the stack contactor is opened and the by-pass contactor is closed to allow the regenerate braking energy to power the system loads.

Abstract: A method for operating a fuel cell system for the provision of electrical power is provided. The fuel cell system is disconnected when control electronics detect a fault. The fault that led to the disconnection is evaluated by the control electronics. An automatic restart of the fuel cell system through the control unit occurs if the evaluation of the fault permits this.

Abstract: A fuel cell system includes: a fuel cell; a normally-closed first shut-off valve provided upstream from the fuel cell and opening and closing pipes c1 and allowing air supplied from an air pump to pass therethrough; a normally-closed second shut-off valve opening and closing a pipe allowing cathode off-gas, discharged from the fuel cell, to pass therethrough; a valve-driving section for opening and closing discs of the shut-off valves; and valve lock units maintaining discs of the shut-off valves in open state when the cathode is released by opening the first shut-off valve and the second shut-off valve during electro-chemical reaction progressing in the fuel cell. This structure provides a simple and small-size fuel cell system capable of maintaining opening state of shut-off valves stably and reliably.

Abstract: A method for operating a fuel cell system for supplying at least one electrical consumer with electric energy is provided. The fuel cell system includes a fuel cell and an accessory for supplying the fuel cell. The efficiency of the fuel cell system is determined and the fuel cell is switched off temporarily when the efficiency of the fuel cell system falls below a switch-limit efficiency.

Abstract: The current disclosure is directed at a method and apparatus for starting of a fuel cell within a mobile communication device under emergency. In one embodiment, the emergency starting apparatus includes a fuel cell starter, such as a piezoelectric element, as an integrated fuel cell starter.

Abstract: A fuel cell system having a fuel cell for causing reactant gas to be electrochemically reacted to generate power, a reactant gas supply path for supplying reactant gas to the fuel cell, a reactant gas recirculation path for recirculating exhaust gas discharged from the fuel cell and combining the recirculating exhaust gas with reactant gas flowing through the reactant gas supply path to the fuel cell, and a pump unit disposed in the reactant gas recirculation path to pump the recirculating exhaust gas through the reactant gas recirculation path. A pump-tempering apparatus increases the temperature of the pump unit and a controller controls the pump-tempering apparatus. After the controller receives a fuel cell system stop signal, the controller controls the pump-tempering apparatus such that the temperature of the pump unit becomes higher than the temperature of piping in the reactant gas recirculation path.

Abstract: The present invention includes a fuel cell (11), a fuel gas supplying device (16), an oxidizing gas supplying device (17) and a control apparatus (20) and further includes at least one of a temperature control device (19) which controls the temperature of the fuel cell (11) and a humidifying device (24) which humidifies at least one of the fuel gas and the oxidizing gas to be supplied to the fuel cell (11), wherein: the control apparatus (20) controls at least one of the temperature control device (19), the humidifying device (24), the fuel cell (11) and the fuel gas supplying device (16) to cause the temperature of the fuel cell (11) to be equal to at least one of the dew point of the fuel gas and the dew point of the oxidizing gas, before cutting off an electrical connection between the fuel cell (11) and a load; and then the control apparatus (20) cuts off the electrical connection between the fuel cell (11) and the load.

Abstract: The invention relates to a method for protecting a set of electrochemical cells incorporated into a fuel cell stack from corrosion during an operation for shutting down the fuel cell stack, which method comprises steps of: measuring the voltage across the terminals of each of the cells to be protected; when the voltage measured for a cell is above a protection threshold, discharging this cell into an electrical load; when the voltage measured for a cell is below said protection threshold, disconnecting this cell from the electrical load.

Abstract: A hydrogen generating apparatus (10) of the present invention includes a desulfurizer (7) which is supplied with a raw material and which is configured to remove sulfur compounds present in the raw material, a reformer (17) which is configured to form a hydrogen containing gas from the raw material which has passed through the desulfurizer (7), a meter device (3) which is configured to measure the amount of sulfur compounds removed by the desulfurizer (7) (which amount is hereinafter referred to as the amount of removal of sulfur compounds), and a controller (40), wherein the controller (40) is configured so as not to permit the next time start-up if the integrated value of the amount of removal of sulfur compounds measured by the meter device (3) becomes greater than or equal to a first threshold value.

Abstract: A method for determining whether a fuel cell stack cooling fluid is flowing at cold fuel cell system start-up. The method monitors the temperature of the cooling fluid outside of the fuel cell stack, and determines whether the temperature of the cooling fluid is increasing properly as the temperature of the stack increases.

Abstract: A fuel cell system (10) includes a pressure decrease valve (121) and a flow control valve (122) provided in a hydrogen supply line (120P) that extends from a high pressure gas tank (110) to a fuel cell (100). A low temperature environment may cause the function of these devices to decrease. Therefore, if the gas temperature inside the high pressure gas tank (110) is higher than the temperature of this low temperature environment and is a temperature at which the decreased function can be recovered, high pressure gas inside the tank is made to flow through the hydrogen supply line (120P) to expose the pressure decrease valve (121) and the like to the relatively high temperature gas before a start signal that starts the system is received.

Abstract: In order to provide a fuel cell system (which ensures high proton conductivity and high energy conversion efficiency and, in addition, copes with an operating mode of the startup/shutdown type and which has excellent durability capable of effectively preventing a polymer electrolyte membrane from deterioration) and an operating method of such a fuel cell system, a fuel cell system (100) is provided with a fuel cell (11), a fuel gas supplier (16) and an oxidizing gas supplier (17), a temperature supplier (19) which controls the temperature of the fuel cell, and a humidifier unit (18) which humidifies oxidizing gas, wherein there is further provided a controller (20) which controls the dew point of fuel gas and the dew point of oxidizing gas as follow: during the generation of electric power, the fuel gas dew point is made higher than or equal to the temperature of the fuel cell while the oxidizing gas dew point is made less than the temperature of the fuel cell and, before interrupting the electric connection

Abstract: A fuel cell system includes a fuel cell, an operation controller and an air-conditioning mechanism. In response to a heating request for the air-conditioning mechanism during ordinary operation where the fuel cell is operated at an operating point on a current-voltage characteristic curve of the fuel cell, the operation controller compares a heat value-based required current value that is a current value of an operating point that is located on the current-voltage characteristic curve and satisfies a required heat value for the fuel cell with an output-based required current value that is a current value of an operating point that is located on the current-voltage characteristic curve and satisfies a required output for the fuel cell. When the output-based required current value is equal to or greater than the heat value-based required current value, the operation controller causes the fuel cell to be operated at an operating point on the current-voltage characteristic curve.

Abstract: A gas supply device for use in a fuel cell system, comprises: a first injector configured to have a first maximum valve-openable pressure; a second injector arranged in parallel with the first injector and configured to have a lower flow rate than the first injector and a greater second maximum valve-openable pressure than the first maximum valve-openable pressure; a first pressure sensor located upstream of the first and second injectors; and a controller configured to control open/close operation of the first and second injectors, wherein at a start of the fuel cell system, (i) when pressure in the upstream of the first and second injectors is greater than the first maximum valve-openable pressure but is less than or equal to the second maximum valve-openable pressure, the controller opens the second injector, and (ii) when the pressure in the upstream of the first and second injectors is less than or equal to the first maximum valve-openable pressure, the controller opens the first injector or the second i

Abstract: A method of removing residual oxygen in a residential high temperature non-humidification fuel cell stack including at least one cathode. The method includes making the pressure in the cathode higher than that outside of the cathode and maintaining airtight sealing of the cathode of the fuel cell stack, removing the residual oxygen in the fuel cell stack, and stopping supplying of fuel to the fuel cell stack. The setting of the pressure includes blocking air flow out of the cathode, comparing the pressure in the cathode with a set pressure higher than the pressure outside the cathode, and supplying air to the cathode until the pressure in the cathode is the same as or is higher than the set pressure.

Abstract: A fuel cell system includes a fuel cell, a fuel gas supply channel, a fuel off-gas discharge channel, an oxidant gas supply channel, an oxidant off-gas discharge channel, a first shut valve, a second shut valve, a shut valve controller, a temperature detector, a scavenging device, and an elapsed-time detector. The elapsed-time detector is configured to detect an elapsed time elapsed from a timing at which the fuel cell is shut down. The scavenging device scavenges the oxidant gas flow channel and the fuel gas flow channel in sequence if the elapsed time detected by the elapsed-time detector is within a first predetermined period of time. The scavenging device scavenges the fuel gas flow channel and the oxidant gas flow channel in sequence if the elapsed time detected by the elapsed-time detector is outside the first predetermined period of time.

Abstract: A method of starting a fuel cell system for a vehicle includes determining whether or not an activation signal of a fuel cell provided in the fuel cell system has been inputted, operating, if it is determined that the activation signal has been inputted, a cooling medium circulation pump to supply a cooling medium to an impurity removal mechanism for reducing a conductivity of the cooling medium, and driving an oxidant gas supply device and a fuel gas supply device in the fuel cell system to start activation of the fuel cell if it is determined that the conductivity of the cooling medium is less than or equal to a predetermined value.

Abstract: Fuel cell device comprising a fuel cell assembly with at least one polymer electrolyte membrane fuel cell and a fuel delivery means for providing a fuel flow. The device is provided with means for pre burning adapted to burn fuel entering the fuel cell assembly during the start up phase until the fuel flow is increased to a predetermined level and/or the oxygen concentration is decreased to a predetermined level. A method of operating the assembly comprises the steps of initiating the start up phase by causing the fuel delivery means to deliver a fuel flow, whereby a means for pre burning burns off fuel entering the fuel cell assembly, monitoring the fuel flow and/or the oxygen concentration and when the fuel flow is increased to a predetermined level and/or the oxygen concentration is decreased to a predetermined.

Abstract: A remedial method for starting a fuel cell system is described. The method includes determining if the remedial method is required; providing air to an exhaust of a fuel cell stack; setting a hydrogen flow rate to an anode side of the fuel cell stack; providing a predetermined volume of hydrogen to the anode side of the fuel cell at the hydrogen flow rate; providing a predetermined volume of air to a cathode side of the fuel cell stack after the predetermined volume of hydrogen has been provided to the anode side while continuing to provide air to the exhaust of the fuel cell stack and hydrogen to the anode side of the fuel cell stack; determining if a stack voltage is stable after the predetermined volume of air has been provided to the cathode side; and closing the anode outlet valve after the stack voltage is stable.

Abstract: The present invention has been devised in order to solve the problems described above, and an object of the present invention is to provide a fuel cell system that can discharge an impurity in an anode gas flow channel while suppressing wasteful discharge of a fuel gas to the outside of the system. An exhaust valve is connected to a downstream end of an anode gas flow channel of a fuel cell. The exhaust valve has an exhaust mode in which a substantially smaller amount of gas than the consumption of a fuel gas in the anode gas flow channel is discharged to the outside of the system. After a request to stop electric power generation by the fuel cell, the output current value of the fuel cell is increased to a predetermined value. Then, the exhaust valve is set in the exhaust mode before or when the output current value is increased, and the discharge flow rate of the exhaust valve is increased in accordance with the increase of the output current value.

Abstract: A shutdown and self-maintenance operation process of a liquid fuel cell system is introduced. The liquid fuel cell system gives out a shutdown signal and a liquid fuel cell of the liquid fuel cell system stops discharging when receiving the shutdown signal. Thereafter, a self-maintenance operation consisting of the following four steps will be performed: (a) Supply of the cathode gas is stopped in the liquid fuel cell system. (b) After a first duration, the supply of the cathode gas is started. (c) The liquid fuel cell discharges until the output power of the liquid fuel cell is less than or equal to a first predetermined value. (d) The liquid fuel cell stops discharging and the supply of the cathode gas is stopped again. The (a) to (d) four steps are repeated several times before the liquid fuel cell system is completely stopped.

Abstract: The present invention provides a startup control device and method for a fuel cell system. The startup control device includes a concentration meter, a hydrogen feed rate controller, and a controller. The concentration meter measures the concentration of oxygen located in the anode of a fuel cell stack. The hydrogen feed rate controller is disposed at an inlet of the anode. The controller receives an oxygen concentration signal value from the concentration meter while controlling the hydrogen feed rate controller to adjust a hydrogen feed rate to the anode.

Abstract: A fuel cell system including: a fuel cell which generates electrical power through the reaction of a reaction gas; a reaction gas supply device which supplies the reaction gas to the fuel cell; a cooling device which cools the fuel cell by circulating a coolant through the fuel cell; a fuel cell operating temperature output device which outputs a maximum temperature inside the fuel cell as an operating temperature of the fuel cell; and a fuel cell temperature adjustment device which adjusts a temperature inside the fuel cell so that the operating temperature inside the fuel cell is less than a preset upper temperature limit.

Abstract: Disclosed is an apparatus and method for activating a fuel cell stack, which significantly reduces the time required for activation and the amount of hydrogen used for the activation by employing a vacuum wetting process in a shutdown operation. In particular, a high humidity open circuit voltage operation humidifies the fuel cell stack and operates the fuel cell stack at an open circuit voltage, and a vacuum wetting operation wets the surface of a polymer electrolyte membrane by creating a vacuum atmosphere in the fuel cell stack. The high humidity open circuit voltage operation and the vacuum wetting operation are performed alternately and repeatedly.

Abstract: When a stop trigger of a fuel cell system (100) is turned on, air humidified by a humidifier (3) which air having a humidity quantity lower than a humidity quantity at a normal operation is supplied to a fuel cell stack (11). Thereby, a takeout quantity Qm of a moisture generated in the fuel cell stack (1) is increased, then, a power generation of the fuel cell stack (1) is continued for a certain time Pg. Then, the power generation is stopped, and a cathode side of the fuel cell stack (1) is purged with the air for a certain time Pp.

Abstract: A method for determining if more hydrogen has been added to a fuel cell system than a predetermined threshold amount to detect leaks in an anode subsystem or a cathode subsystem of a fuel cell system. The method includes determining a quantity of hydrogen added to the fuel cell system for a given period of time during a predetermined operating condition of the fuel cell system and determining whether the quantity of hydrogen added is more than the predetermined threshold amount. The method also includes adapting an anode subsystem reactant gas concentration model if the quantity of hydrogen added to the fuel cell system is more than the predetermined threshold amount to provide precise control of pressure in the anode subsystem and the cathode subsystem of the fuel cell system.

Abstract: A controller (15) performs a stop operation of stopping electric power generation by a fuel cell (3); then performs an activity recovery operation of stopping the supply of a fuel gas by a fuel gas supply unit (10) to an anode (2a), causing an anode inert gas supply unit (13) to supply an inert gas to the anode (2a), and causing an oxidizing gas supply unit (11) to supply an oxidizing gas to a cathode (2b); and performs control such that the fuel gas supply unit (10) resumes supplying the fuel gas to the anode (2a) to resume the electric power generation by the fuel cell (3) after the cell voltage of the fuel cell (3) which is detected by a voltage detector (14) has decreased to a first voltage or lower.

Abstract: A method for providing an accurate time that a fuel cell system has been shut-down so that the gas constituents in the anode and cathode side of the fuel cell stack can be known for an efficient next system start-up sequence. The method uses two timers, a stand-by timer that provides a time count for how long the fuel cell system has been off, but the vehicle ignition is still on, and a shut-off timer that provides a time count of how long the vehicle ignition has been off. The two time counts are added to give a complete time count of how long the fuel cell stack has been shut-down.

Abstract: A fuel cell system is provided with a judgment unit which makes a gas leak judgment based on a pressure drop of fuel gas in a gas leak detection portion by consuming the fuel gas in the gas leak detection portion of the fuel gas supply system by electric power generation of a fuel cell and causing auxiliary devices to consume the electric power generated by the fuel cell, and comprises a control unit which increases consumption of the fuel gas in the gas leak detection portion by increasing the electric power consumption of the auxiliary devices. With this arrangement, where the electric power generation of the fuel cell and the electric power consumption of the auxiliary devices result in an insufficient consumption of the fuel gas, the consumption of the fuel gas can be accelerated by increasing the electric power consumption of the auxiliary devices. Thereby, a rapid gas leak judgment can be achieved.

Abstract: Disclosed herein is a proton-conducting polymer and uses thereof and, more particularly, a hydrocarbon-based proton-conducting polymer derived from a monomer having a multi-naphthyl group and comprising a plurality of acid groups on the side chain of the repeating unit, an electrolyte membrane comprising the polymer, a membrane-electrode assembly comprising the electrolyte membrane, and a fuel cell comprising the membrane-electrode assembly.

Abstract: A fuel cell system having a fuel cell 1, a load 8 connected to the output line of the fuel cell 1 and a control apparatus 20 for controlling an amount of current flowing to the load 8, wherein a stopping state for stopping the fuel cell system includes a first stage stopping state for stopping while remaining hydrogen in the hydrogen line and a second stage stopping state for stopping substituting the hydrogen line with air, and transfers to the second stage stopping state by way of the first stage stopping state.

Abstract: A fuel cell system has a fuel cell for generating electricity by reacting a fuel gas with an oxidant gas and an exhaust flow passage for exhausting the fuel exhaust gas exhausted from a fuel electrode 16 of the fuel cell to the outside. The fuel cell system is equipped with a movable filter device disposed in the exhaust flow passage, so that by activating the movable filter device, water and foreign particles adhering to the filter are quickly scattered by rotational centrifugal force and vibration, thereby preventing the exhaust flow passage from being blocked by the clogging by water freeze and foreign particles and also reducing startup time.

Abstract: A method of starting a polymer electrolyte membrane fuel cell (PEMFC) stack by rapidly increasing its temperature. The PEMFC stack includes: a first flow line connected to cooling plates; a second flow line connected to the cooling plates; a coolant reservoir; a heat exchanger; a by-pass line; a heating element; a first valve installed between the first flow line and the heat exchanger; and a second valve that selectively connects the coolant reservoir, the second flow line, and the by-pass line. The method of starting a PEMFC stack includes: closing the first valve and controlling the second valve so that the second flow line and the by-pass line are connected to each other, and the coolant in the coolant reservoir is not connected to the second flow line and the by-pass line; and heating the coolant in the by-pass line.

Abstract: A polymer represented by the following Formula 1, and a membrane-electrode assembly and a fuel cell system including the polymer: In the above Formula 1, definitions of the substituents are the same as in described in the detailed description.

Abstract: By incorporating a selectively conducting component in electrical series with the anode components in a solid polymer fuel cell, degradation during startup and shutdown can be reduced. As a result, the startup and shutdown procedures can be simplified and consequently certain system apparatus may be omitted. The anode does not need to be rapidly purged with hydrogen on startup or with air on shutdown. Additionally, the auxiliary load usually employed during such purging is not required.

Abstract: A fuel cell system includes a controller that estimates or detects an air replacement state of a fuel electrode and a hydrogen circulation path while the operation of the fuel cell system is stopped. Upon starting the fuel cell system, the controller changes the order in which the operation of a hydrogen circulation pump is started and a hydrogen pressure regulator is opened to start the supply of hydrogen gas on the basis of the estimated or detected air replacement state, thereby preventing deterioration caused by uneven distribution of air and hydrogen in the fuel electrode.

Abstract: A fuel cell system has a fuel cell that includes at least one cell with an electrolyte membrane, an index value acquirer and a controller. The index value acquirer obtains a temperature index value correlated to temperature of a short circuit area in each cell. The controller controls a control parameter of the fuel cell affecting the temperature of the short circuit area, such that the temperature index value is within a predetermined range set to make the temperature of the short circuit area lower than a decomposition temperature of the electrolyte membrane.

Abstract: Included are: a basic operation plan creating section 2 configured to create a basic operation plan based on durable years (e.g., 10 years) and a durable operating time (e.g., 40000 hours) of a fuel cell 1, such that the fuel cell 1 is operated within the range of at least one of a first allowable operating time (e.g., 11 hours) per predetermined unit period (e.g., per day) and the number of durable start-ups (e.g., 4000 times) per predetermined unit period; a special operation plan creating section 3 configured to create a special operation plan such that the fuel cell 1 is operated within the range of at least one of a second allowable operating time (e.g., 20 hours) per predetermined unit period (e.g.

Abstract: A fuel cell system capable of suppressing noise caused by backflow of air when a compressor stops. Also, there is provided a fuel cell vehicle provided with this fuel cell system. A fuel cell system includes a fuel cell and a compressor that compresses air taken in from outside and supplies compressed air to the fuel cell. Operation of the compressor is stopped after a pressure difference between an upstream side and a downstream side of the compressor has become equal to or smaller than a predetermined value by using a control unit. In this case, the predetermined value can be a pressure difference corresponding to a predetermined noise level.

Abstract: The present invention relates to a sulfonated poly(arylene ether) copolymer, a manufacturing method thereof and a polymer electrolyte membrane for fuel cell using the same.

Abstract: The invention is a hydrogen passivation shut down system for a fuel cell power plant (10, 200). During shut down of the plant (10, 200), hydrogen fuel is permitted to transfer between an anode flow path (24, 24?) and a cathode flow path (38, 38?) while a low-pressure hydrogen generator (202) selectively generates an adequate amount of hydrogen and directs flow of the low-pressure hydrogen into the fuel cell (12?) downstream from a hydrogen inlet valve (52?) to maintain the fuel cell (12?) in a passive state.

Abstract: The fuel cell stack (1) may be supplied with oxygen or with atmospheric air as oxidant gas. The fuel cell stack includes a device for filling with pressurized atmospheric air comprising an air intake orifice (126), an oxidant gas recycling loop (12R) and apparatus for isolation from the atmospheric air, such as an isolation valve (128), a cut-off valve (120) or a non-return valve, enabling the supply channel to the cathodes and said recycling loop to be isolated from the atmospheric air. This makes it possible to implement a shut-down procedure comprising the following actions: (i) the supply of fuel gas and oxidant gas is cut off; (ii) current continues to be drawn so as to consume the oxidant gas remaining in the oxidant gas supply system; and (iii) nitrogen-enriched gas is injected into the oxidant gas supply system.

Abstract: A fuel cell system includes an air supply flow path configured to supply the air to a fuel cell, a reed valve provided in the air supply flow path, an air exhaust flow path configured to allow the air discharged from the fuel cell to flow therethrough, a pressure regulating valve provided in the air exhaust flow path and configured to adjust back pressure of the air supplied to the fuel cell, a bypass flow path configured to connect an upstream section of the air supply flow path upstream of the reed valve with the air exhaust flow path, and a bypass valve provided in the bypass flow path and configured to open and close the bypass flow path. The fuel cell system reduces the opening of the pressure regulating valve with supplying the air to the fuel cell in the closed position of the bypass valve, so as to increase the pressure of the air upstream of the pressure regulating valve, and subsequently opens the bypass valve.

Abstract: A fuel cell system is provided that can establish, for a long time period, a stack to an idling stop state. The fuel cell system includes: an idling stop control means for setting the stack to an idling stop state by, decreasing both a supplied amount of air to the stack and generated electric current produced from the stack to less than during the idling power generation; and a discharge valve control means for determining whether there is a necessity to discharge nitrogen or generated water inside of the anode system, and for opening the purge valve or drain valve in a case of there being a necessity. The discharge valve control means shortens valve open times (PO2, DO2) of the purge valve and drain valve during idling stop to less than the valve open times (PO1, DO1) thereof during idling power generation.