Abstract: A method for controlling a fuel cell system includes following steps. It is determined whether an output voltage of a fuel cell stack in the fuel cell system is greater than or equal to a temporary voltage during a first predetermined period, and if yes, an output current of the fuel cell stack is progressively increased during a second predetermined period, and if not, when a variation degree of the output voltage of the fuel cell stack is greater than a predetermined value, the output current of the fuel cell stack is progressively decreased during the second predetermined period. The output voltage of the fuel cell stack is changed in response to progressive increasing or progressive decreasing of the output current of the fuel cell stack, and the temporary voltage is updated to the changed output voltage after a third predetermined period.

Abstract: A method for improving fuel cell system reliability in the event of end cell heater failure in a fuel cell stack. The method includes detecting that an end cell heater has failed. If an end cell heater failure is detected, then the method performs one or more of setting a cooling fluid pump to a predetermined speed that drives a cooling fluid through cooling fluid flow channels in the fuel cell stack, limiting the output power of the fuel cell stack or the net power of the fuel cell system, limiting the maximum temperature of the cooling fluid flowing out of the stack, turning off stack anti-flooding algorithms that may be used to remove water from reactant gas flow channels in the stack, and turning off cathode stoichiometry adjustments for relative humidity control in response to water accumulating in cathode flow channels in the fuel cell stack.

Abstract: A method for reducing the probability of an air/hydrogen front in a fuel cell stack is disclosed that includes closing anode valves for an anode side of the fuel cell stack to permit a desired quantity of hydrogen to be left in the anode side upon shutdown and determining a schedule to inject hydrogen during the time the fuel cell stack is shutdown. The pressure on an anode input line is determined and a discrete amount of hydrogen is injected into the anode side of the stack according to the determined schedule by opening anode input line valves based on the determined pressure along the anode input line so as to inject the hydrogen into the anode side of the stack.

Abstract: A fuel cell power generation system including a fuel cell, a fuel generator, an oxidizing gas supply device, an output controller, an open-close mechanism, and a controller. The controller is configured such that in a stop process, the controller controls the output controller to stop supplying the electric power to an external load; controls the oxidizing gas supply device to stop supplying an oxidizing gas and controls the open-close mechanism to close a passage upstream from an oxidizing gas channel; after the passage upstream from the oxidizing gas channel is closed, stops a raw material gas supply device and a water supply device when a predetermined period has elapsed, during which period a gas in the oxidizing gas channel is replaced by a fuel gas.

Abstract: In a fuel cell system a specific connection and a valve arrangement make it possible for a compressor to supply precompressed air to a fuel cell stack via a waste gas line, said air then leaving the fuel cell stack via a line which is otherwise an air feed line. In this way, a humidifier may be bypassed. This is sensible in particular during a start phase at low ambient temperatures, during which the fuel cell system is intended to warm up without moisture in the fuel cell stack having a negative effect, for instance by freezing. The compressor may be operated both in the start phase or stop phase and during conventional operation by the same mode of operation.

Abstract: In a fuel cell system a specific connection and a valve arrangement make it possible for a compressor to supply precompressed air to a fuel cell stack via a waste gas line, said air then leaving the fuel cell stack via a line which is otherwise an air feed line. In this way, a humidifier may be bypassed. This is sensible in particular during a start phase at low ambient temperatures, during which the fuel cell system is intended to warm up without moisture in the fuel cell stack having a negative effect, for instance by freezing. The compressor may be operated both in the start phase or stop phase and during conventional operation by the same mode of operation.

Abstract: The present invention is directed to a fuel cell system with various features for optimal operations of an electronic device, a battery charger or a fuel refilling device. The fuel cell system includes an information storage device associated with the fuel supply, pump and/or refitting device. The information storage device can be any electronic storage device including, but not limited to, an EEPROM or a PLA. The information storage device can include encrypted information. The information storage device can include software code for confirming the identification of the cartridge before operation of the electronic device and/or refilling device. The information storage device can include instructions for a hot swap operation to shut down property when the fuel supply is ejected while the electronic device is in operation. The present invention is also directed to system architecture for a fuel cell system that utilizes information storage devices.

Abstract: A method of operating a high-temperature fuel cell, the method including increasing the temperature of a fuel cell stack the operation of which has stopped; starting the operation of the fuel cell stack and applying at least a portion of a load to the fuel cell stack when the temperature of the fuel cell stack reaches a first temperature; and applying any remaining load to the fuel cell stack when the temperature of the fuel cell stack reaches a second temperature that is higher than the first temperature.

Abstract: A start-up plating process for a flow cell battery is disclosed. Upon start-up of the flow-cell stack, catalysts may have deplated from the electrodes. The catalyst is replated to the electrode by application of currents to the stack prior to circulating electrolyte fluids.

Abstract: The operational availability of a motor vehicle with a fuel cell is increased by providing that a defined quantity of the output power of the fuel cell system is consumed by a power consumption component in the heating-up phase and/or in the warm-up phase and that the consumed quantity of the output power is converted into power loss by impressing a suitable current into at least one winding of an electric motor which is to be energized.

Abstract: A stop method for a fuel cell system including a fuel cell unit in which hydrogen is supplied to an anode, and air is supplied to a cathode so as to generate electrical power via an electrochemical reaction. The stop method includes the steps of stopping supply of hydrogen to the anode, electrically connecting the anode and the cathode via an electrical load, and supplying air to the anode.

Abstract: A fuel cell system includes: a fuel cell stack for generating electric power by receiving supply of a reaction gas; an air compressor for scavenging water remaining in the fuel cell stack when power generation is stopped; a rechargeable battery for supplying electric power to the air compressor for operation thereof; and a controller for estimating an amount of water remaining in the fuel cell stack based on an alternating-current impedance of the fuel cell stack, estimating a target SOC for charging the rechargeable battery with electric power required for scavenging the amount of water, and controlling charge and discharge so that an SOC of the rechargeable battery agrees with the target SOC.

Abstract: A fuel cell system capable of adequately controlling the water content of a fuel cell is provided. An impedance reference value is stored in a memory for an impedance comparator. The impedance reference value is a reference value that is set in order to prevent the water content in a fuel cell from decreasing too much. The impedance comparator compares a measured impedance value supplied from an impedance operation unit with the impedance reference value and performs scavenging control based on the comparison result.

Abstract: A fuel cell system includes a fuel cell and a supplying unit, which supplies reactive gases to the fuel cell. A control unit includes a power production effective area calculator calculates the areas of the electrodes available for power production as a power production effective area. A current density calculator which calculates a current density of the power production effective area calculated by the power production effective area calculator based on the total amount of power required by the fuel cell. A gas supply amount determiner determines the amount of reactive gas to be supplied to the fuel cell depending on the current density. A gas supply controller controls the supplying unit so as to supply the amount of reactive gas determined by the gas supply amount determiner to the fuel cell.

Abstract: Provided is a fuel cell system which can properly control a refresh operation. A controller controls the refresh operation so that an output voltage does not exceed an avoidance voltage even after the refresh operation. Specifically, the controller estimates the output voltage after the refresh operation from the output voltage before the refresh operation and controls execution of the refresh operation so that the estimated output voltage after the refresh operation does not exceed the avoidance voltage. For example, if before the refresh operation, when judging that the estimated output voltage after the refresh operation does not exceed the avoidance voltage, the controller executes the refresh operation.

Abstract: A fuel cell system (10) of the present invention comprises determination means (50) for consuming a fuel gas present at a gas leak detection portion of a fuel gas supply system (31, 32) through the power generation of a fuel cell (20), and performing a gas leak determination on the basis of a pressure decrease margin of the fuel gas present at the gas leak detection portion, and comprises discharge means (H51) for reducing the pressure at the gas leak detection portion by purging the fuel gas present at the gas leak detection portion to the outside of the fuel gas supply system (31, 32). By not only consuming the fuel gas present at the gas leak detection portion through power generation, but also purging the fuel gas to the outside of the fuel gas supply system, the pressure at the gas leak detection portion can be brought close to a target pressure within a short time period, and the gas leak determination can be performed in a short period of time and with a high level of precision.

Abstract: Voltage rising detection unit detects a voltage rising condition of a fuel cell stack after the supply of reactant gas to the fuel cell stack is started. A control unit determines an internal state of the fuel cell stack on the basis of the detected voltage rising condition of the fuel cell stack, and then decides a subsequent operation of the fuel cell stack in accordance with the determination. This makes it possible to minimize deterioration of the fuel cell stack which is caused by generating power continuously in an unsuitable state.

Abstract: A method of operating a fuel cell system in a vehicle that is switchable to a temporary stop mode and restarted from the stop mode. When, in certain driving situations, it is required to switch to the stop mode, it is then checked whether the operating conditions of the fuel cell system allow a switch to the stop mode. If the switch is allowed it takes place. When a restart of the fuel cell system is required on the basis of the vehicle the settings of the stop mode are cancelled again. The switch to the stop mode involves, with further existing electric contacting of the fuel cell, the air mass flow conveyed by the air conveying device being switched off or reduced to a predefined value and the pressure of the combustion gas supplied being reduced to a predefined value.

Abstract: A fuel cell has an anode, a cathode, and a proton-exchange membrane disposed between the anode and cathode. An exhaust anode gas exhausted from an outlet of the anode is directed back to an inlet of the anode. Hydrogen is added to the exhaust anode gas before the exhaust anode gas reaches the inlet.

Abstract: A fuel cell system that controls the speed of the compressor providing cathode air to a fuel cell stack just after a system start-up procedure has ended so as to reduce the chance that the compressor current draw will cause a stack quick stop. The method includes recognizing a command for high compressor speed just after the system start-up procedure ends, where the stack is in the run state, and instead of providing a step change in the compressor command, ramping up the compressor speed so that the current draw from the compressor does not spike.

Abstract: A fuel cell system capable of reliably and rapidly discharging liquid in a fuel cell stack to the outside is provided. In a fuel cell system having a discharge path (76) that allows discharge of at least liquid in a fuel cell stack (20), at the time of actuation of the fuel cell stack (20), reaction gas is supplied to the fuel cell stack (20) at a higher speed or in a greater amount than during normal operation of the fuel cell stack (20). By supplying the reaction gas at a high speed or in a great amount before actuation, residual liquid in the fuel cell stack (20) can be blown off and thus reliably and rapidly discharged to the outside. The residual liquid can be discharged more easily when a volume (30) is provided in the discharge path (76) or the pressure inside the fuel cell stack (20) is set to a negative level at the time of actuation thereof.

Abstract: A fuel cell system and a starting method therefor are capable of setting a start-up mode which is appropriate to energy stored in a secondary battery so as to eliminate problems in starting the fuel cell system. The fuel cell system includes a fuel cell, a secondary battery which is electrically connected with the fuel cell, a secondary-battery charge-amount detection unit which detects an amount of charge in the secondary battery, and a memory which stores at least one threshold value for determining the start-up mode of the fuel cell system. Stored electric energy which corresponds to the amount of charge in the secondary battery is calculated, and a start-up mode of the fuel cell system is determined based on the electric energy stored in the secondary battery and the threshold value stored in the memory.

Abstract: A fuel cell system having a cooling water pump provided in cooling water piping that sends cooling water to a fuel cell and sending the cooling water under pressure, fuel gas supply piping connected to the fuel cell and supplying fuel gas to the fuel cell, fuel gas circulation piping connected to both the fuel cell and the fuel gas supply piping and circulating fuel gas, discharged from the fuel cell, in the fuel gas supply piping, and a fuel gas pump provided in the fuel gas circulation piping and sending under pressure the fuel gas, discharged from the fuel cell, to the fuel gas supply piping. After operation of the fuel cell is stopped, the fuel gas, discharged from the fuel cell, is sent under pressure by the fuel gas pump, and cooling water is send under pressure by the cooling water pump to cool the fuel cell to thereby reduce the temperature of the fuel cell to a level lower than the temperature of the fuel gas pump.

Abstract: An intermediate circuit for controlling the connection of a fuel cell stack to a load bus includes three switching elements arranged in a pi configuration. At least one such switching element is provided for short circuiting either or both of the fuel cell stack and the load bus, while a further switching element controllably interrupts the line connection between the fuel cell stack and the load bus. The respective switches are driven according to a control method that accommodates start-up operation, switch-off operation, emergency shut down, and a self diagnostic mode.

Abstract: A fuel cell system including a fuel processor, and a method of operating the fuel cell system, the fuel cell system includes: a reformer that reforms a hydrocarbon group fuel source into a reformed gas; a burner that heats the reformer; a CO remover unit that removes CO from a reformed gas generated by the reformer; a stack to generate electricity using the reformed gas; a first burner fuel supply line to supply the hydrocarbon group fuel source to the burner; and a second burner fuel supply line to supply the reformed gas from the CO remover unit to the burner.

Abstract: The present invention relates a power supply apparatus for a fuel cell vehicle, and provides a power supply apparatus of a fuel cell vehicle. More specifically, an IR data transmitter transmits and receives data to/from a hydrogen charger and a power supply apparatus, that is connected to the IR data transmitter, selectively supplies power thereto according to the opening/closing of a fuel door. In particular, a sensing apparatus is connected to the power supply apparatus and senses opening/closing of the fuel door and a normal power source that is connected to the sensing apparatus for opening/closing the fuel door selectively supplies power to the sensing apparatus when the normal power source is off.

Abstract: A method for removing contaminants in a fuel cell comprises: supplying a hydrogen-based fuel to the anode; supplying a first oxidant to the cathode, wherein the first oxidant comprises at least some sulfur dioxide; drawing a primary load from the fuel cell stack while supplying the hydrogen-based fuel to the anode and the air to the cathode; shutting down the fuel cell when a voltage of the fuel cell is equal to or less than a threshold voltage at which sulfur crosses over from the cathode to the anode, wherein shutting down the fuel cell comprises: performing at least one oxidant starvation while drawing the primary load, removing the primary load after performing the at least one oxidant starvation, and bringing the anode to a high potential after removing the primary load; and thereafter, restarting the fuel cell.

Abstract: A start-up method for a fuel cell system that includes a fuel cell that carries out power generation by the electrochemical reaction between a fuel gas and the oxygen gas in the air; a fuel gas discharge path and a fuel gas supply path that are connected to the fuel cell; a fuel gas circulation path in which the fuel gas discharge path merges with the fuel gas supply path; and a purge valve provided on the fuel gas circulation path in order to discharge the circulating fuel gas from the fuel gas circulation path. The method includes the steps of opening the purge valve at the same time that the fuel gas is supplied to the fuel cell and replacing the nitrogen gas that originates in the air and is present in the fuel gas circulation path by fuel gas; and closing the purge valve after the nitrogen gas in the fuel gas circulation path has been replaced by the fuel gas.

Abstract: Disclosed are a fuel cell system and a method of controlling the system to efficiently remove air flowing into an anode side and a cathode side during a stop of a fuel cell vehicle to prevent an overvoltage of a fuel cell stack that is generated at the time of a start-up thereby enhancing a durability of a fuel cell stack. The fuel cell system illustratively includes a concentration detector mounted at a cathode side and/or an anode side of a fuel cell stack to detect the oxygen concentration in the air; a controller that outputs a control signal to release air when the oxygen concentration is greater than a set value; and an absorber that absorbs air from the cathode side and/or the anode side through an absorption line in response to the control signal output from the controller to thereby release the absorbed air to the outside.

Abstract: The present invention provides a hybrid fuel cell system that is configured to determine if an idle stop condition has been satisfied during a normal operation mode of the hybrid fuel cell system, cut off air supply to a fuel cell to stop power generation of the fuel cell and reduce a voltage which the fuel cell outputs in response to determining that the idle stop condition has been satisfied. The voltage of a bidirectional converter, connected between a battery and a bus terminal is reduced and the output of the fuel cell is controlled, based on a first predetermined value and maintained at that first predetermined value. Subsequently, the battery is charged via the output current of the fuel cell generated by maintaining the reduced voltage of the bidirectional converter.

Abstract: A fuel cell system of the present invention is provided with a fuel cell, a fuel gas supply system that supplies a fuel gas to the fuel cell, and an oxidant gas supply system that supplies an oxidant gas to the fuel cell, and, when operation end processing is started, a flow rate of the fuel gas supplied to the fuel cell is increased only by a predetermined amount that is determined based on a temperature environment of the fuel cell system. As a result, when the operation of the fuel cell system is ended, the fuel gas at the optimum flow rate in accordance with the temperature environment is provided, thereby efficiently preventing deterioration of the fuel cell after the end of the operation.

Abstract: A system and method for providing a fuel cell stack purge to remove excess water during system shut-down. A compressor is operated at a shut-down speed to force water out of the cathode flow channels and draw water through the membrane from the anode flow channels so that a desired amount of water is removed from the fuel cell stack without over drying the membrane. The cathode shut-down purge flow can be introduced in the forward or reverse direction. Further, the flow of hydrogen fuel can be directed so that it flows through the anode flow channels in an opposite direction to push water out of an anode outlet manifold into the anode flow channels so that it will also be drawn through the membrane by the cathode airflow. Finally, a brief rehydration step is added after the shut-down purge to achieve the desired water content in the cells.

Abstract: A method for performing a plausibility check of a fuel cell stack anode side pressure sensor to determine whether the pressure sensor is providing an accurate measurement. Prior to system start-up when a cathode side compressor is not providing cathode air to a fuel cell stack, and the cathode side of the stack is at ambient pressure, a pressure measurement from a differential pressure sensor between the anode side and the cathode side of the fuel cell stack is provided. The differential pressure sensor reading is added to a pressure measurement from an ambient pressure sensor, where the sum should be about the same as the pressure measurement from the anode side pressure sensor if the anode side pressure sensor is operating properly.

Abstract: A fuel cell electric generator designed for back-up in the absence of network electricity supply. The generator comprises a fuel cell stack, means for supplying the stack with a first and a second reagent flow comprising, in turn, pressure reducing means, and a manifold body to communicate with the stack said first and second reagent flows and at least a flow of coolant fluid via a respective coolant loop. The manifold body comprises inside chambers for the mixing of said reagent flows with corresponding re-circulated product flows and a coolant fluid expansion chamber within which said pressure reducing means of said first and second reagent flows are positioned at least partially drowned by said coolant. Method for the start-up and shut-down of the generator, and a method for detecting the flooding of a fuel cell and a method for detecting the presence of gas leakages in the generator are also disclosed.

Abstract: A fuel-cell system is advantageous for repressing water from flowing backward from a reservoir to a condenser, flowing backward which results from the inside of the condenser being turned into negative pressure. The fuel-cell system has a fuel cell for generating electric power by reactant gas, a condenser for generating condensed water by condensing water content included in the reactant gas to be supplied to the fuel cell or in off gas of the reactant gas, and a reservoir for reserving the condensed water collected at the condenser. A drain valve is disposed between the condenser and the reservoir. The drain valve is switchable between a closed state in which communication between the condenser and the reservoir is shut off and an opened state in which the condenser is communicated with the reservoir to discharge the water in the condenser to the reservoir. A controller carries out inner-pressure increment and drain controls for opening the drain valve after increasing inner pressure in the condenser.

Abstract: A power supply apparatus for a line connection type fuel cell system includes a power converter system (PCS) control power supply which generates PCS control power from line power, a balance of plant (BOP) power supply which generates BOP power from line power, a regulator which generates PCS control power from the BOP power, a first switching unit switched by a control signal, which directs the line power to one of the PCS control power supply and the BOP power supply, a second switching unit switched by a control signal, which selects an output of one of the PCS control power supply and the regulator to provide PCS control power, and a controller which controls switching of the first and second switching units in response to a starting command.

Abstract: There is disclosed a fuel cell system capable of drying a fuel cell in a short time after a system stop instruction is issued. The fuel cell system includes a controller to control the execution of a normal operation and a dry operation which decreases the water content of the fuel cell as compared with the normal operation. The controller executes the dry operation prior to the system stop instruction so that the water content of the fuel cell is decreased as compared with the normal operation at a time of the system stop instruction. The controller may execute the dry operation before the system stop instruction in a case where it is predicted that the temperature of the fuel cell at the system stop or the next system start is a predetermined low temperature.

Abstract: A fuel cell system capable of reducing time spent before actual execution of low-temperature countermeasure processing is provided. At the time of activation, a control unit for the fuel cell system refers to, for example, a detected FC temperature and judges whether or not the low-temperature countermeasure processing is necessary for the activation. If the control unit determines that the low-temperature countermeasure processing is necessary, it controls an output voltage of the fuel cell to be a target voltage for the low-temperature countermeasure processing, without having the fuel cell enter an OCV state, and then executes the low-temperature countermeasure processing.

Abstract: A method for operating a direct methanol fuel cell is provided. The fuel cell includes a fuel cell main body having a fuel electrode and an air electrode disposed in opposing positions on either side of an electrolyte film. In this method, an aqueous methanol solution is supplied directly to the fuel electrode. A quantity of the aqueous methanol solution supplied is controlled in accordance with an electric current value drawn from the fuel cell main body so as to minimize a quantity of unused methanol within a discharge fluid discharged from the fuel electrode.

Abstract: The present invention provides a heating control method for a fuel cell vehicle, in which an additional heating source is used together with a typical electric heater to reduce power consumption and increase fuel efficiency as compared to the sole use of the electric heater. For this purpose, the present invention provides a heating control method for a fuel cell vehicle which comprises an electric heater for heating air supplied to the interior of the vehicle, and a heater core provided in a coolant line for cooling a fuel cell stack and heating the air supplied to the interior of the vehicle by heat exchange with the coolant discharged from the fuel cell stack.

Abstract: The present invention provides a purging device and method for improving cold start performance of a fuel cell by direct heating, in which a gas mixture of hydrogen and air is supplied to a cathode of a fuel cell stack after shutdown of a fuel cell system to generate heat by a reaction of hydrogen and air, and the generated heat is used to increase the temperature of the fuel cell stack and, at the same time, remove water from the fuel cell stack.

Abstract: The present invention seeks, when a temporary abnormality occurs in a voltage converter, a recovery of the voltage converter, and minimizes the inadequacy of the drive power. In a fuel cell system comprising an electric storage device disposed with a voltage converter, in the case where an abnormality occurs in the voltage converter, the voltage converter is stopped once, an attempt is made to recover the voltage converter to a normal state after the voltage converter is stopped, and drive power is generated in at least a fuel cell until the voltage converter recovers to the normal state. It is preferred that an upper limit of the power which can be generated when the voltage converter recovers to the normal state be set to a value lower than an upper limit of power obtained prior to the occurrence of the abnormality. Further, it is preferred that the limit be canceled step by step when recovering the voltage converter to a normal state.

Abstract: A fuel cell power system includes a fuel cell stack prepared by stacking a plurality of electric cells, each having an anode and a cathode with an electrolyte therebetween, a fuel supply line and an oxidant supply line that respectively supply a fuel and an oxidant to the fuel cell stack, and a fuel exhaust line and an oxidant exhaust line that respectively exhaust the fuel and oxidant supplied to the fuel cell stack.

Abstract: A fuel cell system for power generation comprising a solid polymer type fuel cell having a solid polymer electrolyte membrane for separating an anode gas and a cathode gas, a resistor, an inverter, a switch for switching the inverter and the resister with respect to the fuel cell, the switch and the inverter, a supply conduit and discharge conduit for the anode gas and the cathode gas, and a supply vale and a discharge valve. When a molar ratio of the hydrogen contained in the anode gas to oxygen contained in the cathode gas becomes 2/1 or less at the time of the stop of the fuel cell, the supply valve for air is closed.

Abstract: A fuel cell system which includes: a fuel cell having a fuel gas flow path and an oxidant gas flow path and generating electricity by being supplied a fuel gas to the fuel gas flow path and an oxidant gas to the oxidant gas flow path; fuel gas supplying means; a discharge valve; fuel gas exchange means for exchanging an atmosphere inside the fuel gas flow path for the fuel gas at a starting of the system; and cold start determination means for determining whether to conduct or not to conduct the cold start of the system, wherein when the cold start determination means determines to conduct the cold start, the cold start determination means increases a total discharge amount of a gas to be discharged for exchanging the atmosphere inside the fuel gas flow path for the fuel gas, and thereby increases a fuel gas concentration in the fuel gas flow path.

Abstract: A fuel cell system and a method for operating the same are disclosed. In one embodiment, a fuel cell system includes a fuel supplier, a reformer for reforming a fuel supplied from the fuel supplier into hydrogen gas by a reforming reaction, and a fuel cell stack for generating electrical energy by an electrochemical reaction between the hydrogen gas and an oxidizing agent. When the fuel cell system is to be stopped, the reforming reaction of the reformer and the electrochemical reaction of the fuel cell are stopped and a portion of unreformed fuel is fed to the reformer and the fuel cell stack. Residual hydrogen is reacted and residual power from the fuel cell stack is dissipated by a power dissipation circuit. By largely removing hydrogen from the fuel cell stack on a stopped condition, reactions that are detrimental to the fuel cell membrane are reduced.

Abstract: A process for controlling the length of a purge and the purge rate of a fuel cell stack at system shut-down so as to provide the desired amount of stack humidity. The membrane humidification is measured at system shut-down by a high frequency resistance sensor that detects membrane humidification and provides the measurement to a controller. The controller controls the compressor that provides cathode input air to the fuel cell stack so that the time of the purge and the flow rate of the purge provide a desired membrane humidity for the next start-up.

Abstract: A fuel cell system includes: a fuel cell activation portion that starts electricity generation of a fuel cell; a cooling medium passage that is provided with a pump and that is provided for passing a cooling medium through a cell-side passage for the cooling medium; and a pump control portion that stops the pump for a first predetermined period after a start of the electricity generation caused by the fuel cell activation portion at a time when a temperature of the fuel cell is a low temperature lower than or equal to a predetermined value, and that starts operating the pump after the first predetermined period elapses. The pump control portion includes a cooling medium reverse portion that alternately reverses a direction of flow of the cooling medium in the cell-side passage according to elapsed time by controlling operation of the pump after the first predetermined period elapses.

Abstract: The invention relates to a fuel cell system and method comprising a reformer with a thermal starting device, at least one gas processing stage downstream of the reformer, at least one fuel cell disposed downstream of the gas processing stage and a plurality of bipolar plates, the fuel cell having an inner region of a reaction with anode, cathode and electrolyte, and an outer region with at least one cooling channel permitting a coolant to flow through the cooling channel, wherein the outer region is not in fluid connection with the inner region. Upstream of the fuel cell, the fuel cell system has a switching device, which is switchable between a start-up position and an operating position, wherein in the operating position the product gases from the reformer and/or the thermal starting device are guided to the inner region of the fuel cell.

Abstract: A fuel cell having an oxygen-containing gas flow field and a fuel gas flow field, an oxygen-containing gas supply apparatus for supplying an oxygen-containing gas to the oxygen-containing gas flow field, a fuel gas supply apparatus for supplying a fuel gas to the fuel gas flow field, a scavenging gas supply apparatus for supplying air as a scavenging gas to the fuel gas flow field, and a controller are provided. The controller includes a voltage detection unit for detecting the voltage of the fuel cell after operation of the fuel cell is stopped and a scavenging control unit for starting scavenging in the fuel gas flow field by the scavenging gas supply apparatus after the detected voltage is decreased temporarily, increased, and decreased again to become a preset voltage or less.