Abstract: A fuel cell system includes a plurality of solid oxide fuel cells arranged in a fuel cell stack, an integrated heat exchanger/reformer operable to partially reform an anode feed prior to entry into the fuel cell stack, an anode tailgas oxidizer, and an offgas flow path extending away from an anode side of the fuel cell stack and having a first branch to selectively combine offgas from the anode side of the fuel cell stack with fuel from a fuel source to comprise the anode feed to the fuel cell stack and a second branch to supply offgas from the anode side of the fuel cell stack to the anode tailgas oxidizer. The integrated heat exchanger/reformer transfers heat from the oxidized offgas from the anode tailgas oxidizer to the anode feed before the anode feed enters the anode side of the fuel cell stack. The offgas from the anode tailgas oxidizer provides the sole heat source for the anode feed traveling through the integrated heat exchanger/reformer.

Abstract: An FC voltage increasing converter includes a plurality of converter parts having reactors. Regarding the first of the plurality of converter parts provided with a thermistor, the output starts to be limited when the temperature detected by the thermistor reaches a limitation starting temperature, which is obtained based on a reference heat-resistant temperature, which is obtained by subtracting an error of the thermistor from a specification heat-resistant temperature of each of the reactors. Meanwhile, regarding the second, third and fourth of the plurality of converter parts not provided with thermistors, the outputs start to be limited when the temperature detected by the thermistor reaches a limitation starting temperature obtained based on an allowable temperature, which is obtained by subtracting a characteristic-variation temperature of the reactor from the reference heat-resistant temperature of the reactor.

Abstract: A membrane electrode assembly includes a reactor constructed from a ion-permeable membrane between a cathode space and an anode space. The membrane includes an extended membrane area which extends outside of the area of the cathode and anode spaces. A carrier layer is attached to and supports the membrane extended area, and the carrier layer is arranged with an integrated circuit adjacent to the fuel cell.

Abstract: A method for charging electric vehicles includes receiving information regarding an electric vehicle. At least a portion of the information is received through a vehicle interface configured to place a battery of the electric vehicle into electrical communication with a fuel cell system. A charge is delivered from the fuel cell system to the battery of the electric vehicle through the vehicle interface without use of a direct current to alternating current (DC/AC) converter. The charge is delivered based at least in part on the information.

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.

Abstract: Disclosed are a device and method for detecting the coolant level in a thermal management system for a fuel cell vehicle, which can accurately and rapidly detect the lack of coolant using a detection value of a pressure sensor. That is, the present invention provides a device and method for detecting the coolant level in a thermal management system for a fuel cell vehicle, which can accurately and rapidly monitor the lack of coolant by calculating in real time the lack of coolant based on a change in slope value and a change in amplitude of a detection value of a pressure sensor according to the flow of coolant while the pressure sensor is mounted in a coolant line connected to an inlet of a fuel cell stack and a reservoir is connected to a pressure cap of a radiator.

Abstract: A method and an apparatus of reacting reaction components. The method comprises electro-chemically reacting reaction components on opposite sides of at least one membrane with at least one catalyst encompassing a respective volume. In another embodiment, the method includes conducting electrolysis, such as electrolysis of water. The apparatus includes at least one membrane with first and second sides encompassing a respective volume. The apparatus further includes at least one catalyst coupled to the first and second sides to electro-chemically react reaction components on the first and second sides in gaseous communication with the at least one catalyst, and a cover coupled to the at least one membrane to separate flow paths on the first and second sides.

Abstract: A cooling system of a fuel cell is provided with a main cooling flow passage and a bypass cooling flow passage which is arranged parallel with the main cooling flow passage and diverts the same coolant, as flow passages through which coolant flows. A radiator and a coolant circulation pump (WP) and the like are arranged in the main cooling flow passage. Coolant from the main cooling flow passage enters the bypass cooling flow passage and reaches a second heat exchanger via a case of a motor of an ACP and the like. At the second heat exchanger, heat exchange is also performed with a supply gas flow passage, after which the coolant returns to the main cooling flow passage. The manner in which the coolant is distributed can be changed depending on where the coolant is diverted from the main cooling flow passage and the arrangement of the circulation pump.

Abstract: A fuel cell system having an adaptable compressor map and method for optimizing the adaptable compressor map is provided. The method includes the steps of establishing an initial operating setpoint for an air compressor based on the adaptable compressor map; monitoring a surge indicator; adjusting the adaptable compressor map based on the monitored surge indicator; determining a desired operating setpoint based on the adjusted adaptable compressor map; and establishing an adapted operating setpoint for the air compressor based on the adaptable compressor map following the adjustment thereof. The steps are repeated until the adaptable compressor map for the air compressor is optimized.

Abstract: The present invention is directed to a solid oxide fuel cell system with a load following function. The system sets a command power value, based on the amount of load, and instructs an inverter to achieve a permitted power value corresponding to the command power value, which is a permitted amount of power to be extracted from the fuel cell system. The system also changes an amount of change per unit time in the next inverter permitted power value.

Abstract: A fuel cell is disclosed which is formed on a semiconductor wafer by etching channel in the wafer and forming electronics on the substrate electronically coupled to the fuel cell that controls generation of power by the fuel cell through electrical communication with the fuel cell. A hydrogen fuel is admitted into one of the divided channels and an oxidant into the other. The hydrogen reacts with a catalyst formed on an anode electrode at the hydrogen side of the channel to release hydrogen ions (protons) which are absorbed into the PEM. The protons migrate through the PEM and recombine with return hydrogen electrons on a cathode electrode on the oxygen side of the PEM and the oxygen to form water.

Abstract: This disclosure relates to module level redundancy for fuel cell systems. A monitoring component monitors a set of operational parameters for a fuel cell group. The fuel cell group includes a set of fuel cell units, each having a set of fuel cell stacks. The fuel cell stacks include a set of gas powered fuel cells that convert air and fuel into electricity using a chemical reaction. The monitoring component determines that the set of operational parameters do not satisfy a set of operational criteria, and, in response, a load balancing component adjusts the electrical output capacity of the set of fuel cell units included in the fuel cell group.

Abstract: A contact arrangement is described for connecting a power supply to electrical components in a vehicle. The contact arrangement may include a first mechanical contact for connecting a first lead of the power supply to an electrical component, and a second mechanical contact for connecting a second lead of a power supply to the electrical component. The first and second mechanical contacts are configured to disconnect the power supply in the event of a collision. The first mechanical contact is configured to be arranged substantially perpendicular to the second mechanical contact in relation to a transverse plane of the vehicle.

Abstract: A fuel cell system includes a fuel cell generating electricity through reaction between fuel and oxidant gases; an air compressor supplying air, as the oxidant gas, to the fuel cell; a shut-off valve interrupting exhaust of air as fuel cell exhaust gas; an air flow meter measuring the flow rate of air supplied to the fuel cell; a pressure sensor measuring a supplied air pressure; and a control unit controlling power generation reaction of the fuel cell, calculating a first calculated air flow rate based on a value measured by the air flow meter and a second calculated air flow rate based on a system volume from the air compressor to the shut-off valve, an air pressure increase in the system volume, calculated based on a value measured by the pressure sensor, and an atmospheric pressure, and calculating a ratio of the second to first calculated air flow rates.

Abstract: A stable, high output is obtained with an anion exchange membrane-type fuel cell that generates electricity when air is supplied. An operating method for an anion exchange membrane-type fuel cell includes an anion exchange membrane electrode assembly for which an anode is joined to one surface of a anion exchange membrane and a cathode is joined to the other surface, and air is supplied to the cathode, wherein air with a reduced carbon dioxide concentration in the atmosphere is supplied to the cathode by a low carbon dioxide air supply system that supplies air with the reduced carbon dioxide concentration to the cathode.

Abstract: Various embodiments enable the operation of fuel cell system support equipment using variable frequency drives and power from fuel cells and/or grid power sources.

Abstract: A system and method for controlling the speed of a compressor in the event that an airflow meter that measures the airflow from the compressor to the cathode input of the stack fails. When a failure of the airflow meter is detected, an algorithm first deactivates the primary feedback control algorithms used to control cathode pressure and flow, and sets the cathode exhaust valve to a fully open position. The speed of the compressor is controlled by an open loop set-point and the airflow from the compressor is estimated by a model using compressor discharge pressure and the compressor speed. The cathode by-pass valve position is determined by calculating the difference between the requested cathode airflow and the modeled compressor output flow. The position of the by-pass valve is then adjusted using the valve characteristics and the compressor discharge pressure. The estimated airflow to the stack is used to control the maximum stack current.

Abstract: A method to control the heat balance of fuel cell stacks in a fuel cell system, the fuel cell system including at least one fuel cell unit including fuel cell stacks, whose fuel cells include an anode side and a cathode side, as well as an electrolyte interposed therebetween, and a recuperator unit for heat exchange for preheating a supply flow of the cathode side. In the method, a desired portion is separated from the fuel exhaust flow coming from the anode side and adapted to be mixed with the cathode side exit flow before said recuperator unit. Also provided is a fuel cell system implementing the method.

Abstract: A system and method for determining a loss of cooling fluid from a thermal sub-system in a fuel cell system. The method includes monitoring current feedback from a high temperature pump that pumps the cooling fluid through a coolant loop. A measured current from the pump is compared to an expected current for the system operating conditions, and if that current is significantly less than what is expected, then it may be as a result of low cooling fluid. If the measured current is less than the expected current for a predetermined period of time, then the system can take mitigating action as a result of a low cooling fluid. Further, if the pump speed is too low to provide an accurate current measurement, then it can be increased if an overflow tank level sensor indicates a low cooling fluid level.

Abstract: A method and system are disclosed for reducing the consumption of safety gas in a fuel cell system having at least one fuel cell unit whose fuel cells include an anode side and a cathode side, as well as an electrolyte interposed therebetween. A supply is provided for supplying the anode with a safety gas, and an exhaust is provided for exhausting the fuel cell unit of a spent safety gas coming from the anode side. The method can adapt a specific percentage of the spent safety gas flow coming from the anode side of the fuel cells to be re-supplied into the anode side of the fuel cells.

Abstract: A fuel cell system for an aircraft is stated, which fuel cell system comprises a fuel cell unit and a suction module. The suction module is used to draw oxygen through the fuel cell unit. No vacuum generators are used during cruising flight.

Abstract: The present disclosure is directed to systems and methods for independently controlling the operation of fuel cell stacks and to fuel cell systems incorporating the same. These systems and methods may include providing a fuel cell system including a plurality of fuel cell stacks and at least a first energy storage device and controlling the operation of the plurality of fuel cell stacks based at least in part on a variable associated with the fuel cell system and/or an energy consuming device. These systems and methods may further include beginning production of electrical output from the fuel cell system responsive to a start condition, initiating production of electrical output from the plurality of fuel cell stacks responsive to a plurality of stack start conditions, and ceasing the production of electrical output from the fuel cell stacks responsive to at least a first stack stop condition.

Abstract: Methods and systems for electrical determination and adjustment of the fuel concentration in direct methanol fuel cells (DMFC) are provided.

Abstract: A fuel cell system (1) which includes: a fuel cell (2) to be supplied with a gas for power generation, the gas unused for the power generation to be discharged out of the fuel cell (2); a circulation flow path (8) through which the discharged gas is resupplied to the fuel cell (2); a variable flow rate circulation pump (6) for circulating the gas through the circulation flow path (8); a valve (7) for discharging the gas in the circulation flow path (8) to the outside thereof; a voltage sensor (22) for measuring voltage of the fuel cell (2); and a controller (32) for controlling the circulation pump (6) and the valve (7). The circulation pump (6) and the valve (7) are controlled based on the voltage (CV) measured by the voltage sensor (22).

Abstract: A fuel cell system is disclosed, wherein the fuel cell system is heated by a fluid during a starting operation to mitigate against vapor condensation and ice formation in a fuel cell assembly and to decrease a warm up time of the fuel cell system.

Abstract: A hydrogen-oxygen fuel cell including a main cell and an auxiliary cell sharing a common electrolyte and having at least one separate electrode, circuitry for measuring the humidity ratio of the electrolyte, and control and switching circuitry for operating the main and auxiliary cells in parallel on a same load or separately on two different loads.

Abstract: A power supply apparatus has a combined power source with power cells configured electrically independently. A switch arbitrarily changes connection paths of the power cells by selectively connecting terminals of the power cells through switching elements. A detector detects differences in electrical potentials between power cell terminals. An output detector detects a power consumption in a load and/or an output power of the power source. ON-OFF states of the switching elements are controlled by a control signal generated based on voltage signals representing detected differences in electrical potentials, power consumption, and output power. A connection status of each power cell is controlled so as to halt outputting of the power cell having the lowest output voltage if it is detected that a detected power value is equal to or lower than an output power preset based on a power generating capacity of the power source.

Abstract: A controller (81) in a fuel cell system (1A) operates a fuel cell (60) in a normal mode or in a special mode which is switched by the controller (81); in which in the normal mode, the fuel cell (60) is operated so as to satisfy at least one of a first operation condition and a second operation condition, the first operation condition being a condition in which an operation time of the fuel cell per unit period is equal to or shorter than a unit allowable operation time defined based on a total durable operation time of at least one of the fuel cell and the auxiliary device, the second operation condition being a condition in which the number of times of operation of the fuel cell per unit time is equal to or less than a unit allowable number of times of operation defined based on a total durable number of times of operation of at least one of the fuel cell and the auxiliary device, and in the special mode, the fuel cell (60) is operated without being limited by at least one of the first operation condition an

Abstract: The patent relates to fuel cell systems and controlling fuel cell systems. One fuel cell system includes at least one fuel cell stack that includes multiple different serially arranged cells. The system also includes at least one component configured to effect an operating environment of the at least one fuel cell stack. The system further includes a controller configured to operate the at least one component at a primary control point relating to one or more parameters of the operating environment. The controller is further configured to temporarily adjust the at least one component to a secondary control point relating to the one or more parameters. The controller can then re-adjust the at least one component to the primary control point. The fuel cell system can achieve greater overall performance than can be obtained without the adjusting and re-adjusting.

Abstract: A system and method for operating a fuel cell system in a stand-by mode. The method includes determining a power limit value based on fuel cell stack and battery power optimization, where if a system power request falls below the power limit value the system will enter the stand-by mode. The system first enters a dynamic stand-by mode where the fuel cell stack is turned off and a compressor providing cathode air to the cathode side of the stack is operated at an idle speed. The method accumulates a compressor power value identifying how much energy has been consumed by operating the compressor at the idle speed during the dynamic stand-by mode, and then switches to a static stand-by mode where the compressor is turned off when the accumulated compressor power value reaches a compressor restart energy value that identifies how much energy it takes to start the compressor.

Abstract: A system for determining the concentration of hydrogen in an anode sub-system of a fuel cell system. The fuel cell system includes at least one fuel cell, an anode inlet, an anode outlet, an anode recirculation line, a source of hydrogen gas and an injector for injecting the hydrogen gas. First and second acoustic sensors are provided in the anode recirculation line and are spaced a known distance from each other. A controller that is responsive to the output signals from the first and second acoustic sensors determines the concentration of hydrogen gas in the anode recirculation line based on the time between when the controller receives the sensor signal from the first sensor and receives the sensor signal from the second sensor.

Abstract: A system and method for controlling the speed of a compressor that provides air to the cathode side of a fuel cell stack in the event that a cathode by-pass valve fails. If a by-pass valve failure is detected, a failure algorithm first disengages the normal flow and pressure algorithms used to control the airflow to the cathode side of the stack. Next, the failure algorithm opens the cathode exhaust gas valve to its fully opened position. Then, in response to a stack power request, the compressor control will be put in an open-loop control where a look-up table is used to provide a particular compressor speed for a power request. An airflow meter will measure the airflow to the stack, and the stack current will be limited based on that airflow.

Abstract: A fuel cell stack that includes catalyzed surfaces in the non-active inlet region of the cathode flow channels. At cold system start-up, hydrogen is introduced into the cathode inlet header to be mixed with air so that a chemical reaction is provided by the catalyst that generates heat to warm the cooling fluid in the non-active inlet area. Therefore, the cooling fluid that enters the active area of the stack will not be cold enough to quench the chemical reaction.

Abstract: There is provided a method for the activation of a fuel cell. An exemplary method comprises operating the fuel cell entirely or partially at least briefly in an electrolysis regimen during galvanic operation.

Abstract: In order to assure drive of a drive motor, a boost operation of a boost device is appropriately performed by judging whether a voltage supplied from a fuel cell suffices a voltage required for driving the drive motor, thereby suppressing a switching loss by the boost device. A fuel cell system is a power source for driving a load. The system includes: a drive motor driven by an electric power; a fuel cell which generates electricity by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen and supplies an electric power to the drive motor; a first boost device which can boosts the voltage outputted from the fuel cell and supplies the boosted voltage to the drive motor; and boost control means which controls voltage boost performed by the first boost device according to the relationship between the fuel cell output voltage and the voltage required by the drive motor.

Abstract: A fuel cell system according to the present invention is characterized by comprising a measurement unit which measures an impedance of a fuel cell in a predetermined frequency region, and a regulation unit which regulates an amount of a gas to be supplied to the fuel cell based on a measured value of the impedance in the predetermined frequency region. According to such a constitution, the impedance of the fuel cell in the predetermined frequency region (e.g., a low frequency region) is measured, and the amount of the gas (e.g., an amount of an oxidizing gas) to be supplied to the fuel cell is regulated based on this measured value of the impedance. Here, since the impedance of the fuel cell in the predetermined frequency region largely differs with a fuel supply state (see FIG. 2), the amount of the gas to be supplied to the fuel cell can be regulated based on the measured value of the impedance to realize a highly efficient and stable operation.

Abstract: A fuel cell system is provided with a fuel cell for supplying generated electric power to external power loads connected to a system power source, a reforming apparatus for supplying fuel gas generated by reforming unreformed fuel to the fuel cell, and a controller for controlling the operations of the fuel cell and the reforming apparatus. When having been unable to normally stop the fuel cell system due to the system power source falling in a power failure, the controller automatically executes a recovery operation so that the fuel cell system is brought into a restartable state, and upon completion of the recovery operation, brings the fuel cell system into a standby state. Thus, a normal restart subsequent to a power failure becomes possible without the need for human labor.

Abstract: A method for filling a fuel cell system with a fuel during start-up is disclosed, the method including the steps of providing a fuel cell stack having a plurality of fuels cells, each fuel cell having an active area, the fuel cell stack including an anode supply manifold and an anode exhaust manifold, the anode supply manifold and in fluid communication with a source of fuel; providing an anode sub-system in fluid communication with an anode side of the fuel cell stack; and supplying the fuel to the fuel cell stack substantially uniformly and substantially simultaneously to compress any fluids in the fuel cell stack into a volume between an end of each active area adjacent to the anode exhaust manifold and an outlet of the anode sub-system.

Abstract: A power generation system and a fuel processor for use within a power generation system. A fuel processor is connected to both a fuel supply line and a water supply line. The fuel processor reacts the hydrocarbon fuel with the water to produce hydrogen gas and raffinate gases. The hydrogen gas is directed into a hydrogen gas line. The raffinate gases are directed into a raffinate gas line. A fuel cell is powered using the hydrogen gas. A heat exchanger is provided that exchanges heat between the fuel supply line, the water supply line, the hydrogen gas line and the raffinate gas line. This enables heat to be recycled. In addition the raffinate gases also travel into a water recovery subsystem. The water recovery subsystem condenses water out of the raffinate gases The recovered water is returned to the system.

Abstract: Contemplated electrochemical devices and methods include an electrolyte flow path in which substantially all of the electrolyte has laminar flow. A segmented electrode contacts the electrolyte, and each of the segments in the segmented electrode is preferably coupled to a control device to provide control over the flow of current to and/or from the electrolyte. Thus, it should be appreciated that the redox state of the electrolyte can be changed in a single-pass through the flow path, which effectively eliminates problems associated with mass transport phenomena and reduced current efficiency.

Abstract: A drive circuit comprising a DC bus configured to supply power to a load, a first fuel cell coupled to the DC bus and configured to provide a first power output to the DC bus, and a second fuel cell coupled to the DC bus and configured to provide a second power output to the DC bus supplemental to the first fuel cell. The drive circuit further includes an energy storage device coupled to the DC bus and configured to receive energy from the DC bus when a combined output of the first and second fuel cells is greater than a power demand from a load, and provide energy to the DC bus when the combined output of the first and second fuel cells is less than the power demand from the load.

Abstract: Disclosed are a device and method for detecting the coolant level in a thermal management system for a fuel cell vehicle, which can accurately and rapidly detect the lack of coolant using a detection value of a pressure sensor. That is, the present invention provides a device and method for detecting the coolant level in a thermal management system for a fuel cell vehicle, which can accurately and rapidly monitor the lack of coolant by calculating in real time the lack of coolant based on a change in slope value and a change in amplitude of a detection value of a pressure sensor according to the flow of coolant while the pressure sensor is mounted in a coolant line connected to an inlet of a fuel cell stack and a reservoir is connected to a pressure cap of a radiator.

Abstract: A method (300) and device (400) for augmenting the useful life of an energy storage device in a portable electronic device is disclosed. The method (300) can include the steps of: providing (315) a power module comprising a fuel cell and a battery; determining (310) relative humidity; and controlling (315) the operations of the power module in response to the determined relative humidity. Advantageously, the method (300) and device (400) can augment and prolong the useful life of an energy storage device in a portable electronic device, with minimal power drain.

Abstract: A method for managing fuel cell power increases in a fuel cell system using an air flow feedback delay. The method comprises the steps of determining a required air mass flow rate at a predetermined point in the fuel cell system, determining an actual air mass flow at a predetermined point in the fuel cell system, calculating an air flow feedback delay as a function of the required air mass flow rate and the actual air mass flow, and delaying an external circuit from increasing current draw from the fuel cell stack by the magnitude of the air flow feedback delay.

Abstract: The invention relates to a mixing system for inerting a gas volume. A first exhaust gas that is provided by a fuel cell, and a second exhaust gas that is provided by a hydrogen reformer, can be mixed to form an inert gas mixture. The mixture can be fed into the gas volume for inerting.

Abstract: A fire protection system for reducing the danger of fire, which has a fuel cell for producing a nitrogen-enriched cathode exhaust air. The fuel cell is supplied with air and a fuel. Within the fuel cell, the air is then reduced to a determined oxygen content. The exhaust air is supplied to the room to be protected.

Abstract: A method of shutting down operation of a fuel cell system comprising a fuel cell stack, the method comprising the sequential steps of: i) ceasing a supply of fuel to the fuel cell stack; ii) closing a shut-off valve on an exhaust line in fluid communication with a cathode system of the fuel cell system, the cathode system comprising a cathode fluid flow path passing through the fuel cell stack; iii) pressurising the cathode system with an air compressor in fluid communication with a cathode air inlet port in the fuel cell stack; and iv) ejecting water from the cathode flow path.

Abstract: The present invention provides a method for generating a gas that may be used for startup and shutdown of a fuel cell. In a non-limiting embodiment, the method may include generating a nitrogen-rich stream; merging the nitrogen-rich stream with a hydrocarbon fuel stream into a feed mixture stream; and catalytically converting the feed mixture into a reducing gas.

Abstract: A hydrogen system (10) comprising a reformer (12), in which a vaporized hydrocarbon fuel (50) is reformed to yield a reformate gas (62) comprising hydrogen, and a hydrogen consumer (40), the reformer and the hydrogen consumer being arranged in fluid communication such that the reformate gas can be fed to the hydrogen consumer, the hydrogen consumer, when in use, consuming at least a part of the hydrogen produced by the reformer wherein the hydrogen system further comprises:—an off gas burner (35) which is arranged such that it is in fluid communication with the hydrogen consumer and a first heat exchanger (21), in which offgas burner, when in use, remaining reformate gas in offgas from the hydrogen consumer is combusted, producing exhaust gas (53) which is passed through the first heat exchanger;—at least one air pump (30) which is arranged such that it is in fluid communication with the reformer and the offgas burner, the at least one air pump, when in use, supplying air to said reformer and offgas burner,—a

Abstract: A fuel cell vehicle is provided. The voltage of a fuel cell is fixed, by a DC/DC converter, to a voltage outside an oxidation reduction progress voltage range of the fuel cell. In this state, oxygen concentration or hydrogen concentration is decreased by a gas supply unit, and electric power outputted from the fuel cell is decreased. In this state, regenerative electric power generated by regeneration is collected into a battery.