Abstract: A fuel cell system having a direct liquid fuel cell that uses a liquid containing a formic acid or an alcohol as a fuel includes: a fuel tank that stores the fuel to be supplied to the fuel cell; a fuel supply device that supplies the fuel in the fuel tank to the fuel cell; and a bubbling device that blows an inert gas into the fuel stored in the fuel tank.

Abstract: A duct for a fuel cell module includes an upper duct hood having an inlet configured to receive reactant gas from a supply duct, the upper duct hood defining a first tapered portion and a second tapered portion. The duct further includes a lower duct hood fluidly coupled to the upper duct hood, the lower duct hood defining at least one outlet. In a side view, the second tapered portion is tapered inwardly in a downstream direction. In a top view, the first tapered portion is tapered inwardly in a downstream direction, and the second tapered portion is tapered outwardly moving downstream.

Abstract: A centrifugal blower system has internal gas mixing capability.

Abstract: A fuel cell system includes a fuel cell assembly that includes a plurality of individual fuel cells, each fuel cell having an electrolyte medium, a cathode and an anode; and at least one centrifugal blower system for providing a flow of gaseous medium to the fuel cell assembly. The centrifugal blower system includes a series of blower units, each blower unit in the series comprising a casing having an axial inlet and a radial outlet, an impeller disposed within the casing for drawing a gaseous medium at a first pressure in the axial inlet and expelling gaseous medium at a second higher pressure through the radial outlet, and a motor for driving the impeller; and a duct connecting the radial outlet of at least one blower unit in the series of blower units with the axial inlet of at least one successive blower unit in the series of blower units.

Abstract: A system and method for assembling and compressing a fuel cell stack. The system and method include a fuel cell stack housing with a plurality of side walls that create an enclosure that is open on two opposing ends, at least one channel formed on an inner side wall surface, and a first end structural frame that is affixed to one of the open ends of the housing, the first end structural frame including at least one tooling opening through a planar surface. The system and method further include tooling that passes through the at least one tooling opening of the first end structural frame and that extends up through the housing to the open end of the housing, the tooling capable of moving down incrementally while fuel cell stack components are being loaded into the housing through the open end that is opposite to the first end structural frame.

Abstract: A fuel cell stack (1) includes a plurality of stacked power generation cells (3), a heat exchange unit (7) provided between adjacent two of the power generation cells, a fuel gas supply path arranged to supply the power generation cells with a fuel gas, and an oxidant gas supply path (3, 7, 33, 34, 38) arranged to supply the power generation cells with an oxidant gas, wherein the fuel gas supply path includes in series a first path (7, 31) passing through the heat exchange unit (7), a second path (3, 32, 35, 37) passing through some of the plurality of power generation cells (3) in parallel, and a third path (3, 32, 36) passing through the other power generation cells in parallel.

Abstract: A fuel cell (FC) system operating as its own hydrogen leak detector. The system including at least one cathode and cathode conduit for passage of oxidant to the cathode and a housing containing one or more FCs and defining a plenum around the FC. A ventilation system forces air from the plenum into the cathode conduit and a control system monitors the FC voltage and detects a drop in voltage attributable to hydrogen in the cathode conduit. A control system may include actual cell voltage monitoring of the FC or of one or more cells in the FC stack and a processor for receiving inputs indicative of the operation of the FC or FC stack and/or to determine an expected voltage of FC(s) being monitored and whether the difference between the actual and expected voltage(s) exceeds a predetermined threshold indicative of a predetermined level of hydrogen in the cathode conduit.

Abstract: It is an object of the present invention to provide a current collector including an aluminum porous body suitable for an electrode for a nonaqueous electrolyte battery and an electrode for a capacitor electrode, and an electrode using the current collector. In the three-dimensional network aluminum porous body for a current collector of the present invention, when a sheet-shaped three-dimensional aluminum porous body is divided in the width direction into a central region and two end regions with the central region situated therebetween, the weight per unit area of aluminum in the aluminum porous body at the two end regions is larger than the weight per unit area of aluminum in the aluminum porous body at the central region.

Abstract: In a method for operating a high-temperature fuel cell, which in normal mode of generating electrical power is supplied with liquid fuel, preferably diesel oil, and is preceded on the anode side by a reformer for liquid fuel, where at least part of the hot anode exhaust gas is recirculated into the anode circuit via a recirculation line. Upstream of a compressor preceding the reformer the liquid fuel is sprayed or injected into the hot anode exhaust gas, the quantity of air needed for reforming the liquid fuel being added to the mixture of anode exhaust gas and fuel. On change-over from normal operational mode to standby mode without power generation, the supply of liquid fuel and air is stopped and the gas mixture present in the anode circuit be permanently circulated. A defined amount of air being introduced into the anode circuit in order to remove deposits and contaminations in the high-temperature fuel cell following standby operation.

Abstract: A PEM fuel system includes a fuel cell stack comprising one or more PEM fuel cells and fan configured to provide process air to supply oxidizer to and cool the fuel cell stack. The system has an air duct coupled to the fan and the fuel cell stack, and an electrical service load coupled to the fuel cell stack for receiving electrical power generated from reactions within the fuel cell stack. The system further includes as auxiliary electrical load coupled to the fuel cell stack and located within the air duct to reduce potentials across the fuel cell stack. The air duct is configured to direct the flow of air to the fuel cell stack and auxiliary electrical load to provide cooling air to the fuel cell stack and auxiliary electrical load.

Abstract: A fuel cell system includes a fuel cell assembly medium and at least one centrifugal blower system for providing a flow of gaseous medium to the fuel cell assembly.

Abstract: A fuel cell is provided with a separator that supports an electrolyte/electrode assembly sandwiched therebetween. The separator is provided with: first and second fuel gas supply parts in the center of which fuel gas supply holes are formed; first and second cross-link parts connected to the first and second fuel gas supply parts; and first and second surrounding support parts connected to the first and second cross-link parts. Each first surrounding support part is provided with a set of fuel gas exhaust passages that discharge fuel gas that has gone through a fuel gas passage and been used. The cross-sectional areas of the fuel gas exhaust passages are larger on the downstream sides than on the upstream sides, in terms of the direction of fuel gas flow.

Abstract: In a fuel cell system including a fuel cartridge and a fuel supply module, the fuel cartridge includes at least two ports, wherein a first port from among the at least two ports is a fuel inlet port and a second port from among the at least two ports is a fuel outlet port. The fuel cartridge may also include a fuel pouch or the fuel cartridge itself may be the fuel pouch. The fuel supply module may include a fuel circulation structure that circulates the fuel before the fuel is supplied to the stack. The fuel cell system may be equipped with an electronic apparatus and serve as a source of power.

Abstract: A fuel cell interconnect includes a first side containing a first plurality of channels and a second side containing a second plurality of channels. The first and second sides are disposed on opposite sides of the interconnect. The first plurality of channels are configured to provide a serpentine fuel flow field while the second plurality of channels are configured to provide an approximately straight air flow field.

Abstract: The present invention provides a fuel cell stack that has a separator arranged between fuel cells, the separator including: a sandwiching section which sandwiches an electrolyte electrode assembly and includes a fuel gas channel and a separately provided oxygen-containing gas channel; a bridge which is connected to the sandwiching section and includes a reactant gas supply channel; a reactant gas supply section which is connected to the bridge and includes a reactant gas supply passage; and a connecting section that connects the sandwiching section to the bridge.

Abstract: A fuel cell module is configured or operated, or both, such that after a shut down procedure a fuel cell stack is discharged and has its cathode electrodes at least partially blanketed with nitrogen during at least some periods of time. If the fuel cell module is restarted in this condition, electrochemical reactions are limited and do not quickly re-charge the fuel cell stack. To decrease start up time, air is moved into the cathode electrodes before the stack is re-charged. The air may be provided by a pump, fan or blower driven by a battery or by the flow or pressure of stored hydrogen. For example, an additional fan or an operating blower may be driven by a battery until the fuel cell stack is able to supply sufficient current to drive the operating blower for normal operation.

Abstract: A fuel cell system includes a plurality of fuel cell stacks, and one or more devices which in operation of the system provide an azimuthal direction to one or more anode or cathode feed or exhaust fluid flows in the system.

Abstract: A metal halogen electrochemical energy cell system that generates an electrical potential. One embodiment of the system includes at least one cell including at least one positive electrode and at least one negative electrode, at least one electrolyte, a mixing venturi that mixes the electrolyte with a halogen reactant, and a circulation pump that conveys the electrolyte mixed with the halogen reactant through the positive electrode and across the metal electrode. Preferably, the positive electrode comprises porous carbonaceous material, the negative electrode comprises zinc, the metal comprises zinc, the halogen comprises halogen, the electrolyte comprises an aqueous zinc-halide electrolyte, and the halogen reactant comprises a halogen reactant. Also, variations of the system and a method of operation for the systems.

Abstract: A fuel cell pack is disclosed. The fuel cell pack has N membrane electrode assemblies, N?1 connected conductive planes, an independent first electrode conductive layer, and an independent second electrode conductive layer, wherein N is an integer and 2?N?3000. Each connected conductive plane has a first electrode conductive layer and a second electrode conductive layer, wherein the first electrode conductive layer connects to the second electrode conductive layer. The independent first electrode conductive layer is corresponding to the second electrode conductive layer of the N?1th connected conductive plane; the independent second electrode conductive layer is corresponding to the first electrode conductive layer of the 1st connected conductive plane. Each membrane electrode assembly is situated between each first electrode conductive layer and the second electrode conductive layer to form a fuel cell.

Abstract: A fuel cell including a stack in which a plurality of cells are stacked includes an air manifold and a hydrogen manifold on a first side and a second side of the stack, respectively, a jet array including a tubular body inserted in the air manifold or the hydrogen manifold and a plurality of orifices formed in the tubular body and arranged in a longitudinal direction of the tubular body, a pump or a valve for supplying air or hydrogen to the jet array; and a controller that operates the pump or the valve.

Abstract: A fuel cell stack system is configured to uniformly supply a fuel or an electrolytic solution to each of fuel cell elements, and an electronic device using the fuel cell stack system are provided. An electrolytic solution channel allowing an electrolytic solution to flow therethrough is arranged between a fuel electrode and an oxygen electrode, and a fuel channel allowing a fuel to flow therethrough is arranged outside of the fuel electrode. The electrolytic solution channels and the fuel channels of all fuel cell elements are connected in series to one another. That is, the fuel or the electrolytic solution emitted from an outlet of the fuel channel or the electrolytic solution channel of one fuel cell element enters into an inlet of the fuel channel or the electrolytic solution channel of the next fuel cell element through a connection channel.

Abstract: In one embodiment, a bipolar plate includes a wall area and a landing area defining a fluid flow channel, and a plurality of wires extending from at least one of the landing area and the wall area. In another embodiment, an electrochemical cell includes the aforementioned bipolar plate and a gas diffusion layer (GDL) adjacent the bipolar plate and contacting at least a portion of the plurality of wires.

Abstract: A cell frame in which the structure of a positive electrode electrolyte flow path and the structure of a negative electrode electrolyte flow path are different from each other, a cell stack in which the structure of at least one of the positive electrode electrolyte flow path and the negative electrode electrolyte flow path differs between the cell frame positioned at the center and the cell frame positioned at an end, the cell stack being configured such that electrical resistance in at least one of the positive electrode electrolyte flow path and the negative electrode electrolyte flow path increases from the cell frame positioned at the center toward the cell frame positioned at the end, and a redox flow battery utilizing them.

Abstract: The fuel cell system is simplified and made more compact while providing the favorable recirculation of hydrogen-containing off-gas regardless of the increase or decrease in its flow rate. The fuel cell system is provided with: a cell unit that generates electricity by means of separating hydrogen-containing gas and oxygen-containing gas from each other while placing in flow contact to each other; and a recirculation mechanism for recirculating to the cell unit hydrogen-containing off-gas discharged from the cell unit. The fuel cell system has a flow rate determination unit that determines whether or not the hydrogen-containing gas fed to the cell unit is less than a predetermined flow rate; and a gas feeding pressure varying mechanism that cause the pressure of the hydrogen-containing gas to vary to increase and decrease when it is determined that the hydrogen-containing gas fed to the cell unit is less than the predetermined flow quantity.

Abstract: A fuel cell system including: a fuel cell stack including plural fuel cells sandwiched between two end plates; a fuel supply system supplying a stream of fuel gas to the fuel cell stack; an oxidizer supply system supplying a stream of oxidizer gas to the fuel cell stack; a closed loop coolant circulation system driving a cooling liquid through the fuel cell stack so that the cooling liquid enters the fuel cell stack, absorbs heat from the fuel cells, and exits the fuel cell stack. The coolant circulation system includes a circulation pump driving the cooling liquid, a heat exchanger removing heat from the cooling liquid and for at least partially transferring the heat to the stream of fuel gas and/or the stream of oxidizer gas.

Abstract: A direct carbon fuel cell DCFC system (5), the system comprising an electrochemical cell, the electrochemical cell (10) comprising a cathode (30), a solid state first electrolyte (25) and an anode (20), wherein, the system further comprises an anode chamber containing a second electrolyte (125) and a fuel (120). The system, when using molten carbonate as second electrolyte, is preferably purged with CO2 via purge gas inlet (60).

Abstract: A fuel cell stack includes a plurality of power generation units, a reactant gas channel, and a coolant channel. The plurality of power generation units are stacked in a stacking direction to provide a stacked body and each includes a first separator, a first electrolyte electrode assembly, a second separator, a second electrolyte electrode assembly, and a third separator. The first electrolyte electrode assembly is provided on the first separator. The second separator is provided on the first electrolyte electrode assembly. The second electrolyte electrode assembly is provided on the second separator. The first electrolyte electrode assembly and the second electrolyte electrode assembly each include an electrolyte and a pair of electrodes sandwiching the electrolyte therebetween. The third separator is provided on the second electrolyte electrode assembly.

Abstract: A ceramic baffle is configured to place a load on a stack of electrochemical cells and direct a reactant feed flow stream to the stack.

Abstract: A membrane-electrode assembly includes: a polymer electrolyte membrane; catalyst layers disposed on the polymer electrolyte membrane; and gas diffusion layers respectively disposed on the catalyst layers. Each of the gas diffusion layers is constituted by a porous member containing electrically-conductive particles and polymer resin as major components, and a ratio (y/x) of a tensile strength y (N/cm) of the gas diffusion layer to a dry-wet size change rate x (%) of the polymer electrolyte membrane is 0.10 or higher.

Abstract: Described herein are solid oxide fuel cells and manufacturing methods thereof. In certain aspects, the solid oxide fuel cells described herein include a plurality of anodes and a plurality of cathodes in which the anodes and cathodes are alternately stacked on each other and have non-overlapping sections in which the anodes and cathodes do not overlap partially. In certain aspects, the plurality of anodes are electrically connected to a first electrode, and the plurality of cathodes are electrically connected to a second electrode. In certain aspects, a solid electrolyte can be included, for example, between the anode and the cathode. In certain aspects, partitioning sections are disposed between each of the cathodes and the first electrode and between each of the anodes and the second electrode.

Abstract: A fuel cell (1) includes an electromotive unit (2) having a membrane electrode assembly (MEA) (12), a fuel storage unit (4) storing a liquid fuel, and a fuel supply mechanism (3) supplying the fuel from the fuel storage unit (4) to a fuel electrode (7) of the membrane electrode assembly (12). The membrane electrode assembly (12) has a gas vent hole (17) provided in a manner to penetrate through at least an electrolyte membrane (11) to let a gas component generated on a side of the fuel electrode (7) escape to a side of an air electrode (10).

Abstract: A fuel cell includes a plurality of power generation cells each having a first separator. The separator has a fuel gas flow field. A fuel gas supply passage extends through one corner of the power generation cell in the stacking direction, a fuel gas flowing through the fuel gas supply passage into a fuel gas flow field. An inlet buffer is provided upstream of the fuel gas flow field. The fuel gas supply passage and the inlet buffer are connected by a plurality of inlet connection grooves. The inlet connection grooves are inclined from a direction perpendicular to a wall surface of the fuel gas supply passage toward the center of the fuel gas flow field.

Abstract: A phosphoric acid fuel cell according to one embodiment includes an array of microchannels defined by a porous electrolyte support structure extending between bottom and upper support layers, the microchannels including fuel and oxidant microchannels; fuel electrodes formed along some of the microchannels; and air electrodes formed along other of the microchannels. A method of making a phosphoric acid fuel cell according to one embodiment includes etching an array of microchannels in a substrate, thereby forming walls between the microchannels; processing the walls to make the walls porous, thereby forming a porous electrolyte support structure; forming anode electrodes along some of the walls; forming cathode electrodes along other of the walls; and filling the porous electrolyte support structure with a phosphoric acid electrolyte. Additional embodiments are also disclosed.

Abstract: Disclosed is a fuel cell including, a stack having fuel channels through which fuel flows and air channels through which air flows, the fuel channels and air channels being located at both sides of a reaction film, an actuator disposed to be involved in the air channels, the actuator allowing external air of the stack to affect the air channels, and a skirt extending from the stack with communicating with the air channels.

Abstract: Disclosed herein are various embodiments of redox flow battery systems having modular reactant storage capabilities. Accordingly to various embodiments, a redox flow battery system may include an anolyte storage module configured to interface with other anolyte storage modules, a catholyte storage module configured to interface with other catholyte storage modules, and a reactor cell having reactant compartments in fluid communication with the anolyte and catholyte storage modules. By utilizing modular storage modules to store anolyte and catholyte reactants, the redox flow battery system may be scalable without significantly altering existing system components.

Abstract: A fuel cell component includes a first fluid distribution layer, a second fluid distribution layer, a cap layer, a third fluid distribution layer, and a pair of fluid diffusion medium layers. The individual layers are polymeric, mechanically integrated, and formed from a radiation-sensitive material. The first fluid distribution layer, the second fluid distribution layer, the cap layer, the third fluid distribution layer, and the pair of fluid diffusion medium layers are coated with an electrically conductive material. A pair of the fuel cell components may be arranged in a stack with a membrane electrode assembly therebetween to form a fuel cell.

Abstract: Provided is a fuel cell which has a buffer space provided on a downstream side of a fuel supply space, and in which an output of a most downstream fuel cell unit is less affected by impurity gas stored in the fuel supply space.

Abstract: A flow battery includes a stack of flow cells, a stack of cell frames supporting the stack of cells, stack level and cell level flow manifolds located in the stack of cell frames, and at least one sealing or shunt current mitigation feature.

Abstract: A direct Fuel Cell is based on organic liquid hydrogen storage materials, and includes a fuel cell unit connected to load through AC/DC convert circuit. The outlet and inlet of hydrogen storage materials on the fuel cell unit is connected to hydrogen storage tank through hydrogen storage output pipe and hydrogen storage input pipe, respectively. There is a pump for hydrogenated hydrogen storage materials on the hydrogenated hydrogen storage materials input pipe; the second outlet for water and gas on the fuel cell unit is connected to water tank through the second water output pipe. The water and gas inlet on the fuel cell unit is connected with oxygen input pipe; there is a gas outlet on the top of the water tank; the hydrogen storage materials tank contains hydrogen storage materials. The mentioned hydrogen storage materials are a multi-component mixture of liquid unsaturated heterocyclic aromatics.

Abstract: A stack (10) of fuel cells (11) is to be tested for tightness of the fuel cell membranes. For this purpose, a tracer gas is introduced into the fuel feed channel (15) of the stack (10). The fuel discharge channel (16) is either open or it is closed. A carrier gas is fed to the feed air channel. (17) and led through the exhaust air channel (18) to a gas sensor (28) where a determination is made whether the carrier gas contains amounts of tracer gas. A defective fuel cell (11) can be located by introducing a lance comprising a sniffing probe into the corresponding channel (18) and determining the position of the probe.

Abstract: A fuel cell comprising at least two stacked fuel cell boards (22) which each comprise a membrane of substantially gas impervious electrolyte material and at least two electrode pairs wherein the anode and cathode of each said electrode pair are arranged on respective faces of said membrane. An electrode of each pair of electrodes is connected to an electrode of an adjacent pair of electrodes by a through-membrane connection (13) or by an external connection on a Printed Circuit Board, comprising an electrically conductive region of said electrolyte material. A method for forming the through-membrane electrical connections in the electrolyte membrane is also disclosed.

Abstract: A fuel cell comprises an electrolyte electrode assembly which includes an anode electrode, a cathode electrode, and an electrolyte; a separator which includes a sandwiching portion; a fuel gas channel which is formed at a first surface of the sandwiching portion, and is covered by the anode electrode; fuel gas outlets which are formed around the fuel gas channel; an oxygen-containing gas channel which is formed at a second surface of the sandwiching portion, and is covered by the cathode electrode; and oxygen-containing gas outlets which are formed around the oxygen-containing gas channel, in which the oxygen-containing gas outlets are formed at phases different from phases of the fuel gas outlets in a thickness direction of the separator.

Abstract: The present invention provides a fuel cell in which an electrolyte electrode assembly having an electrolyte sandwiched between an anode and a cathode is provided between separators, each of the separators including: a sandwiching section which sandwiches an electrolyte electrode assembly and includes a fuel gas channel and a separately provided oxygen-containing gas channel; a bridge which is connected to the sandwiching section and includes a reactant gas supply channel; a reactant gas supply section which is connected to the bridge and includes a reactant gas supply passage; and a connecting section that connects the sandwiching section to the bridge.

Abstract: An object is to supply a sufficient amount of air to a fuel cell stack in a fuel cell vehicle when the fuel cell stack is mounted below a floor, the fuel cell stack configured to draw in air through an intake duct and discharge air to the exterior through an exhaust duct. An air introduction surface (26) faces upward or downward in a vehicle upper and lower direction, an intake passage portion (30) of the intake duct (28) extends along the air introduction surface (26) and vertical walls (31, 32) of left and right end portions of the fuel cell stack (11) while a pair of air introduction ports (33, 34) opens in left and right end portions of the intake passage portion (30), and an exhaust passage portion (39) of the exhaust duct (29) extends along an air discharge surface (27) and vertical walls (40, 41) of front and rear end portions of the fuel cell stack (11) while a pair of air discharge ports (42, 43) opens in front and rear end portions of the exhaust passage portion (39).

Abstract: A fuel cell module includes a power generating unit including a cell stack having connected therein a plurality of cells that generate power by using a hydrogen-containing gas and an oxidant, and a housing accommodating the power generating unit. The housing includes an accommodation chamber having a power generating unit arrangement surface where the power generating unit is disposed and a first side wall section and accommodating the power generating unit, and an oxidant flow channel that is formed on the outside of the accommodation chamber, with the first side wall section being interposed therebetween, and allows the oxidant to pass therethrough. A through hole is formed that connects the accommodation chamber with the oxidant flow channel and serves to supply the oxidant to the cell stack.

Abstract: A fuel cell system includes: a fuel cell stack in which end plates are respectively disposed at two ends of a unit-cell stack of unit cells in the stacking direction, and in which a fuel gas channel for conveying a fuel gas along surfaces of one of the end plates in a direction parallel to the surfaces of the one end plate is formed within the one end plate; an injector that is integrally provided in one of the surfaces of the one end plate and that injects the fuel gas into the fuel gas channel; and a relief valve that is integrally provided in the other of the surfaces of the one end plate and that prevents overpressure in the fuel gas channel. The relief valve is disposed at a position offset from an injection axis of the injector.

Abstract: A current producing cell has anode flow plates 22 and cathode flow plates 20. Each of the flow plates 20, 22 defines a membrane face 26, a collector face 24, and a center axis C perpendicular to the membrane face 26 and the collector face 24. Each of the collector faces 24 define a plurality of cooling channels 74, 76, 78 and a plurality of transport channels 62, 64. The cooling channels 74, 76, 78 of the cathode flow plates 20 extend radially relative to the center axis C thereof to overlap the transport channels 62, 64 of the anode flow plates 22.

Abstract: Provided are an ion conductive resin fiber, an ion conductive hybrid membrane, a membrane electrode assembly and a fuel cell. The ion conductive resin fiber comprises an inner layer including an ion conductive resin; and an outer layer including an ion conductive resin having larger EW than the ion conductive resin of the inner layer, and surrounding the inner layer. The ion conductive resin fiber and the ion conductive hybrid membrane are excellent in ion conductivity, polar solvent stability and dimensional stability under low humidity conditions. The fuel cell manufactured using the same has advantages of stable operation and management of a system at ease, removal or reduction of components related to water management, and even in case of low relative humidity, operation at high temperature of 80° C. or higher.

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: There is disclosed a fuel cell system or the like capable of sufficiently reducing an exhaust hydrogen concentration even in a case where a fuel cell is operated in a state of a low power generation efficiency. A bypass valve is arranged between an oxidation gas supply path and a cathode-off gas channel. In a state in which supply of an oxidation gas to a cathode falls short, pumping hydrogen is included in a cathode-off gas. Therefore, a valve open degree of the bypass valve is regulated, and a flow rate of bypass air is regulated to control the exhaust hydrogen concentration.