Abstract: Provided is a fuel cell as a fired body including a porous plate-like support substrate having a gas flow path formed therein, and a power generation element part provided on a principal surface of the support substrate, the power generation element part including at least a fuel electrode, a solid electrolyte, and an air electrode laminated in this order. The generation of cracks in the support substrate has a strong correlation with a “surface roughness of a wall surface of a gas flow” of the fuel cell in a state of a reductant. When the surface roughness of the wall surface of the gas flow path is 0.16 to 5.2 in terms of an arithmetic average roughness Ra in a state in which the fuel cell is a reductant that has been subjected to heat treatment in a reducing atmosphere, the generation of the cracks can be suppressed.

Abstract: A fuel cell and a method for manufacturing a fuel cell from a hollow fiber membrane module. The fuel cell has a housing in which a bundle of hollow fiber membranes is arranged. The volume enclosed by the housing is subdivided into an inlet space, an intermediate space and an outlet space by a partition wall which tightly encloses one end-face portion of the bundle of hollow fiber membranes and a partition wall which tightly encloses the other end-face portion of the bundle of hollow fiber membranes. The inlet space is in a fluid connection with one open end of the hollow fiber membranes, while the outlet space is in a fluid connection with the other open end of the hollow fiber membranes. The fuel cell is distinguished by a simplified electrical connection of all of the electrical layers forming the anode and cathode. As a result, the fuel cell can be produced cost-effectively in large numbers.

Abstract: A cathode-side gas flow path of a cell that forms part of a fuel cell is formed by a first expanded metal arranged on a gas inlet side, and a second expanded metal arranged on a downstream side. The first expanded metal is such that mesh is arranged in a straight line, and gas that flows on a gas diffusion layer side is separated from gas that flows on a separator side. The gas flowrate on the gas inlet side is reduced, so the amount of produced water that is carried away is reduced. As a result, the gas inlet side is inhibited from becoming dry at high temperatures.

Abstract: The present disclosure is directed towards flow structures in electrochemical cells for use in high differential pressure operations. The flow structure on the low pressure-side of the cell has a larger surface area than the flow structure on the high-pressure side of the cell at the flow structure—MEA interface. The boundary of the high pressure flow structure is entirely within the boundary of the low pressure flow structure. A seal around the high pressure flow structure is also contained within the boundary of the low pressure flow structure. In such an arrangement, high fluid pressures acting on the electrolyte membrane from the high-pressure side of the cell is fully and continuously balanced by the flow structure on the low pressure-side of the membrane. Use of the low pressure flow structure as a membrane support prevents the rupture or deformation of the membrane under high stresses.

Abstract: Disclosed herein is a method for estimating a power of a fuel cell. The method includes estimating a predictive current at a predetermined voltage in a controller, based on a present current-voltage characteristic of the fuel cell while the temperature of the fuel cell is being raised, estimating a first power, based on the estimated predictive current and the predetermined voltage, after the step of estimating the predictive current, estimating a second power based on a cell voltage rate while estimating the first power, and calculating an available power of the fuel cell, based on the first power and the second power, after the step of estimating the first power and the step of estimating the second power are performed.

Abstract: The embodiments described and claimed herein are apparatus, systems, and methods for charging an electric vehicle at a stationary service station. In one embodiment, the service station includes a power generation component including at least one fuel cell, a fuel supply component for supplying fuel to the power generation component, a charging component including at least one customer charging station, and a control component for controlling and monitoring the other components and for providing accounting and billing functions.

Abstract: An apparatus for delivering a primary fuel stream to a fuel cell stack is provided. The apparatus includes an ejector that is configured to receive the primary fuel stream from a fuel supply. The apparatus is further configured to receive the recirculated fuel stream from the fuel cell stack to provide a combined fluid stream for delivery to the fuel cell stack. The ejector includes an elastic conduit for varying a flow of the combined fluid stream based on a power level of the fuel cell stack.

Abstract: An ejector for supplying a fuel, such as hydrogen, to a stack in a fuel cell system can automatically move a position of a nozzle according to an increase or a decrease of a system load. As a result, it is possible to control a necessary supply of hydrogen and a recirculation flow rate by selecting an area of a nozzle throat in the fuel cell system using the ejector, and specifically, of being automatically controlled to supply hydrogen through a small nozzle at a low load, such that a recirculation amount is increased.

Abstract: A fuel cell includes an electrolyte membrane, a first electrode, a second electrode and a stress suppressing structure. The first electrode is joined to one surface of the electrolyte membrane. The second electrode is joined to an other surface of the electrolyte membrane. The first peripheral section which is at least part of periphery of the first electrode is located on an inner side along a planar direction of the first electrode than respective peripheries of the electrolyte membrane and the second electrode. The stress suppressing structure is configured to suppress concentration of stress on a location along the first peripheral section in the electrolyte membrane.

Abstract: In solid polymer fuel cells employing framed membrane electrode assemblies, a conventional anode compliant seal is employed in combination with a cathode non-compliant seal to provide for a thinner fuel cell design, particularly in the context of a fuel cell stack. This approach is particularly suitable for fuel cells operating at low pressure.

Abstract: Catalyst comprising graphitic carbon and methods of making thereof; said graphitic carbon comprising a metal species, a nitrogen-containing species and a sulfur containing species. A catalyst for oxygen reduction reaction for an alkaline fuel cell was prepared by heating a mixture of cyanamide, carbon black, and a salt selected from an iron sulfate salt and an iron acetate salt at a temperature of from about 700° C. to about 1100° C. under an inert atmosphere. Afterward, the mixture was treated with sulfuric acid at elevated temperature to remove acid soluble components, and the resultant mixture was heated again under an inert atmosphere at the same temperature as the first heat treatment step.

Abstract: A fuel cell includes separators. A second plate of the separator includes a second circular disk section, a second elongated plate section, and a second rectangular section. A fuel gas supply passage extends through the second circular disk section. The second rectangular section has a fuel gas inlet for supplying a fuel gas to a fuel gas channel, an outer ridge, and a fuel gas outlet for discharging the fuel gas, and a detour path forming wall bent in a V-shape toward the fuel gas inlet. A fuel gas inlet is formed in the V-shaped inner area of the detour path forming wall.

Abstract: A flow battery includes a first liquid-porous electrode, a second liquid-porous electrode spaced apart from the first liquid-porous electrode, and an ion-exchange membrane arranged between the first liquid-porous electrode and the second liquid-porous electrode. First and second flow fields are adjacent to the respective first liquid-porous electrode and second liquid-porous electrode. Each of the flow fields includes first channels having at least partially blocked outlets and second channels having at least partially blocked inlets. The second channels are interdigitated with the first channels. The flow fields provide a configuration and method of operation for relatively thin electrodes with moderate pressure drops and forced convective flow through the liquid-porous electrodes.

Abstract: A system and method for estimating an amount of carbon support loss in fuel cells of a fuel cell stack in a vehicle, for example, during vehicle off-times. The system and method include estimating an amount of time that a hydrogen concentration in the fuel cell stack is zero and calculating an amount of carbon loss based on the amount of time that the hydrogen concentration in the fuel cell stack is zero.

Abstract: Welding system and method permit exchange of data with Smart Grid monitors and/or controllers. The welding systems include a welding power supply configured to convert power between the power grid and the welding power supply. A grid interface cooperates with control circuitry to transmit data to and/or from the grid monitors and/or controllers on the grid side. The control circuitry may control operation of the welding power supply based upon data from the grid. The system may include power generation devices (e.g., engine-drive generators) and energy storage devices (e.g., batteries). The control circuitry may control operation of such devices, the exchange of power between them, and the draw of power from the grid or the application of power to the grid based upon the data exchanged with the grid monitors and/or controllers.

Abstract: Provided is fuel cell system capable of eliminating any failure caused by freezing of a discharge valve during a low temperature while preventing an increase in size of the system. A fuel cell system is provided, the system including: a fuel cell; a diluter that dilutes a fuel-off gas discharged from the fuel cell with an oxidant-off gas discharged from the fuel cell to discharge the resulting gas to the outside; a fuel-off gas flow path that connects the fuel cell and the diluter; and a discharge valve that is provided to the fuel-off gas flow path to discharge a fuel-off gas flowing through the fuel-off gas flow path to the outside during a valve opening operation. In the fuel cell system, the discharge valve is integrally attached to the diluter.

Abstract: A method for recovering fuel cell performance by regenerating electrode characteristics through electrode reversal in order to partially recover performance of a degraded polymer electrolyte fuel cell is provided. The method includes reversing electrodes by supplying an anode of a degraded fuel cell stack with air and supplying a cathode thereof with hydrogen and performing a pulse operation by applying current to the reversed electrodes.

Abstract: Systems and methods are disclosing providing for a fuel cell (“FC”) stack assembly utilizing bus bars that accommodate for variations in FC stack heights during assembly. In some embodiments, bus bars consistent with embodiments disclosed herein may be integrally formed with terminal plates out of a single piece of conductive material. Further embodiments of the bus bars disclosed herein may include structures configured to facilitating cooling of the bus bars during operation of the FC system.

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 relates to a fuel cell device with electrolytes flowing by means of percolation through electrodes (1) and (2) having a porous, three-dimensional structure. The invention also relates to the various uses of said fuel cell device in the transport field and station ship field.

Abstract: Fuel cell devices and systems are provided. In certain embodiments, the devices include a ceramic support structure having a length, a width, and a thickness. A reaction zone positioned along a portion of the length is configured to be heated to an operating reaction temperature, and has at least one active layer therein comprising an electrolyte separating first and second opposing electrodes, and active first and second gas passages adjacent the respective first and second electrodes. At least one cold zone positioned from the first end along another portion of the length is configured to remain below the operating reaction temperature. An artery flow passage extends from the first end along the length through the cold zone and into the reaction zone and is fluidicly coupled to the active first gas passage, which extends from the artery flow passage toward at least one side. The thickness of the artery flow passage is greater than the thickness of the active first gas passage.

Abstract: The present invention provides a composite separator for a polymer electrolyte membrane fuel cell (PEMFC) and a method for manufacturing the same, in which a graphite foil prepared by compressing expanded graphite is stacked on a carbon fiber-reinforced composite prepreg or a mixed solution prepared by mixing graphite flake and powder with a resin solvent is applied to the cured composite prepreg such that a graphite layer is integrally molded on the outermost end of the separator.

Abstract: A fuel cell system includes a fuel cell stack, a cathode supply flow passage which is connected to the fuel cell stack and through which cathode gas flows, a cathode off-gas flow passage which is connected to the fuel cell stack and discharges cathode off-gas, a bypass flow passage which is branched off from the cathode supply flow passage and through which a part of the cathode gas flows while bypassing the fuel cell stack, a bypass valve configured to regulate a bypass flow rate in the bypass flow passage and include an atmosphere communication hole, and an anode off-gas flow passage which is connected to the fuel cell stack and discharges anode off-gas. The anode off-gas flow passage joins the bypass flow passage at a side downstream of the cathode off-gas flow passage or the bypass valve, and the bypass valve is formed with a clearance configured to leak a predetermined quantity of gas even in a fully closed state.

Abstract: An electromagnetic main stop valve which is opened by an electromagnetic force of a solenoid with energization of a valve body in a valve-closing direction by energizing unit is provided in a hydrogen tank. A current sensor and the accelerator opening-degree sensor for detecting a use gas flow rate in a fuel cell stack are provided. A pressure sensor for detecting a pressure in the hydrogen tank is provided. The control device sequentially sets the electromagnetic force of the solenoid so that a valve-opening amount is such an amount as to supply a use gas flow rate to the fuel cell stack based on detection values of the current sensor or the accelerator opening-degree sensor, and the pressure sensor. When the flow rate of hydrogen gas flowing into a gas supply path increases due to a hydrogen gas leak, the main stop valve is automatically closed.

Abstract: The present invention relates to a redox flow secondary battery. The redox flow secondary battery of the present invention comprises a unit cell including a pair of electrodes made of a porous metal, wherein the surface of the porous metal is coated with carbon. According to the present invention, a redox flow secondary battery using porous metal electrodes uniformly coated with carbon is provided, thus improving conductivity of the electrodes, and the electrodes have surfaces uniformly coated with a carbon layer having a wide specific surface area, thus improving reactivity. As a result, capacity of the redox flow secondary battery and energy efficiency can be improved and resistance of a cell can be effectively reduced. Further, the electrodes are uniformly coated with a carbon layer, thus also improving corrosion resistance.

Abstract: A pump has a shaft, an impeller arranged on the shaft, and a labyrinth seal which is arranged between stationary and moving parts of the pump. A plurality of blades are arranged on the rotor and a labyrinth seal extends at least between the shaft and a rear portion of the blades. A gap in the labyrinth seal is designed such that liquid water can be actively carried away, with the labyrinth seal for this purpose being designed at least in places with a channel in the form of a spiral and/or a staircase. The invention also relates to a fuel cell system having such a pump.

Abstract: Systems and methods for reducing an amount of unwanted living organisms within an algae cultivation fluid are provided herein. According to some embodiments, methods may include subjecting the algae cultivation fluid to an amount of cavitation, the amount of cavitation being defined by a pressure differential between a downstream pressure and a vapor pressure, the pressure differential divided by half of a product of a fluid density multiplied by a square of a velocity of an apparatus throat.

Abstract: Fuel cell components provide fuel cells on a flexible sheet that defines a wall of a flexible plenum. An external support structure limits expansion of the plenum in response to forces exerted by a pressurized reactant. The external support structure may comprise a portion of a housing of a portable device. Cathodes of the fuel cells may be accessible from an outside of the flexible sheet and exposed to ambient air while anodes of the fuel cell are accessible from an inside of the flexible sheet and exposed to a fuel, such as hydrogen gas.

Abstract: A redox flow battery is illustrated and described, having at least one cell frame enclosing a cell interior and having at least one supply line provided outside the cell frame for supplying electrolyte to the cell interior and/or at least one disposal line provided outside the cell frames for removing electrolyte from the cell interior. In order to provide greater degrees of freedom in the design of the cell so as to make available redox flow batteries with improved properties, it is envisaged that the supply line for supplying electrolyte to the cell interior and/or the disposal line for removing electrolyte from the cell interior is in fluid contact with the cell interior via a plurality of separate flow channels in the cell frame.

Abstract: A shut-off valve or connecting valve capable of connecting a fuel supply to a fuel cell is disclosed. The valve comprises a first valve component and a second valve component. Each valve component has an outer housing and a biased slidable member disposed inside the housing forming an internal seal. During the connection process, the two valve components establish an inter-component seal. Afterward, in one suitable embodiment the slidable member moves inward and opens the internal seal in the valve component to establish a flow path. In another embodiment, the slidable member moves inward and exposes a first filler and the first filler abuts a second filler in the other valve component to establish a flow path. In other embodiments, at least one valve component is sized and dimensioned to limit access to the internal seal.

Abstract: A fuel reservoir for dispensing liquid fuel with a dispensing appliance includes a container having an opening, a liquid fuel in the container, a needle-pierceable septum disposed across the opening of the container, and a locking surface disposed on an exterior surface of the container and configured to engage a locking mechanism of a dispensing appliance.

Abstract: A repeating unit (10) for a fuel cell stack comprises a gas conducting region (8) for conducting a first gas (12) to and along an active surface (14). A barrier (16) is located in the gas conducting region. The gas conducting region comprises, at least over the active surface, a plurality of channels (20, 22, 24, 26, 28, 30, 32, 34) for conducting the first gas along the active surface. At least a first channel (26) among the plurality of channels defines a first flow direction at a first point (46) located closest to the barrier and a second flow direction at a second point (48), wherein a first straight line (50) which extends through the first point (46) and is parallel to the first flow direction misses the barrier (16) while a second straight line (52) which extends through the second point (48) and is parallel to the second flow direction intersects the barrier. The barrier (16) can he located upstream or downstream of the active surface (14).

Abstract: A fuel cell with a recovering unit and a method of driving the same are disclosed. In one embodiment, the fuel cell includes i) an electric generator to generate electricity based on electrochemical reaction, ii) a recovering unit to recover and mix the fuel, unreacted fuel, and gas and water produced by the electrochemical reaction, and supply the mixed fuel to the electric generator, wherein the recovering unit comprises a valve, configured to discharge gas, which is selectively opened and closed depending on the operation of the fuel cell. With this configuration, the gas or the fuel is not introduced into the electric generator, even though the recovering unit is inclined or turned over. Further, even though the fuel cell is not in use for a long time, the mixed fuel is prevented from evaporating through the discharging pipe.

Abstract: A device for cooling and dehumidifying gases includes a first hollow body with a gas inlet, a gas outlet and a condensate drain; a second hollow body with a coolant inlet and a coolant outlet; and a drive unit. The first hollow body encloses the second hollow body at least in part. One of the first hollow body and the second hollow body is pivotally held relative to the other hollow body and includes at least one turbulence-generating body that extends in the direction of the other hollow body. For rotating the pivotally held hollow body the drive unit is couplable to the hollow body. In this manner a single-stage device for cooling and dehumidifying gases that include water vapor is implemented, which device requires little installation space and is of a particularly lightweight construction. Thus the device is particularly well suited for use in vehicles, in particular in aircraft.

Abstract: A water reactive hydrogen fueled power system includes devices and methods to combine reactant fuel materials and aqueous solutions to generate hydrogen. The generated hydrogen is converted in a fuel cell to provide electricity. The water reactive hydrogen fueled power system includes a fuel cell, a water feed tray, and a fuel cartridge to generate power for portable power electronics. The removable fuel cartridge is encompassed by the water feed tray and fuel cell. The water feed tray is refillable with water by a user. The water is then transferred from the water feed tray into the fuel cartridge to generate hydrogen for the fuel cell which then produces power for the user.

Abstract: A fuel cell gas diffusion layer includes a porous member containing electrically-conductive particles and polymeric resin as major components, and a plurality of holes extending from a main surface of the fuel cell gas diffusion layer are formed.

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 a fuel cell system, it is possible to suppress fixation of a fluid circulating device arranged in a fluid passage connected to a fuel cell main body. The fuel cell system is provided with a fuel cell stack, a system main body having respective elements for supplying a fuel gas and respective elements for supplying an oxidizing gas, and a control device. The control device includes a fluid circulating device drive processing unit having a function to forcibly drive the fluid circulating device after determining, based on a judgment related to one or more of a non-use time, an operation state of the system main body, a membrane impedance state of a fuel cell, a temperature of the fuel cell stack, and a background noise, whether or not forced driving to suppress sticking of the fluid circulating device is preferable at that time.

Abstract: An apparatus is used for the recirculation of anode exhaust gases of a fuel cell, with a recirculation blower and at least one jet pump operated by a propulsion gas stream. The propelling medium is in this case a pressurized fuel, for example hydrogen. The anode outlet of the fuel cell is connected to the intake connection of the at least one jet pump. The outlet of the at least one jet pump is then connected to both the anode inlet and the intake connection of the recirculation blower. The output of the recirculation blower can be connected to the intake connection of the at least one jet pump.

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 polymer electrolyte fuel cell of the present invention comprises a membrane-electrode assembly (5), a first separator (6a), and a second separator (6b); the first separator (6a) having a groove-shaped first reaction gas channel (8) on one main surface of the first separator (6a) which contacts the first electrode (4a) such that a plurality of straight-line-shaped first rib portions (11) run along each other; the second electrode (4b) having a groove-shaped second reaction gas channel (9) on one main surface of the second electrode (4b) which contacts the second separator (6b) such that a plurality of straight-line-shaped second rib portions (12) run along each other; a ratio of a first reaction gas channel width of at least an upstream portion (18b) of the first reaction gas channel (8) with respect to a second rib portion (12) is greater than 0 and not greater than 1.

Abstract: Disclosed is a microbial fuel cell cathode assembly comprising a catalyst (6) and an electrically conductive catholyte wicking member (5) having a catalyst contacting surface (5a) in contact with the catalyst, an electrical contact region (5c) for contacting an electrical connector, and a catholyte supply region (5b) for receiving catholyte from a catholyte supply (9), wherein the electrically conductive catholyte wicking member is operable to wick received catholyte from the catholyte supply region to form a film of catholyte on a part of the surface of the catalyst such that a part of the surface of the catalyst is in contact with both the film of catholyte and a part of the surface of the catalyst is in contact with a gas pathway arranged to supply oxygen to the catalyst.

Abstract: A fuel cell assembly includes an anode with a catalyst layer and a gas inlet end, and a cathode with a catalyst layer and a gas inlet end. The assembly comprises a catalyst layer including a first and second set of catalyst segment pairs spaced apart respectively with first and second distances, a first ratio of an average segment width of the first set of catalyst segment pairs relative to the first distance being different from a second ratio of an average segment width of the second set of catalyst segment pairs relative to the second distance.

Abstract: An end plate is joined to a fuel cell stack. A first piping unit and a second piping unit are attached to the end plate. The first piping unit has a first attachment base, to which a fuel gas supply pipe, a first oxidation off-gas discharge pipe, and a coolant discharge pipe are coupled. The second piping unit has a second attachment base, to which an oxidation gas supply pipe, a coolant supply pipe, and a discharge pipe are coupled. The discharge pipe is joined to a discharge cylinder coupled to the first oxidation off-gas discharge pipe. The oxidation gas supply pipe and the coolant supply pipe are integrated with each other. Also, the first oxidation off-gas discharge pipe and the coolant discharge pipe are integrated with each other.

Abstract: According to one embodiment, a fuel cell includes an electric-power generator, a fuel distribution mechanism, and a pump. The electric-power generator includes a membrane electrode assembly including an anode, a cathode, and an electrolytic membrane. The fuel distribution mechanism includes a container and a thin tube. The container includes a fuel discharge surface, and contains the electric-power generator inside. The thin tube is formed in the container in a manner that a fuel outlet and a fuel inlet communicate with each other. The pump is connected directly to the fuel inlet.

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: The invention relates to an electrode compartment for an electrochemical cell, including a bicontinuous micro-e?ulsion, wherein catalytic parts are generated in-situ in a fluid, which can act as a cathode as well as an anode. The electrode compartment comprises a connection to supply fuel or an oxidator, for example oxygen, to the compartment. The electrode compartment is part of a refreshing system with a reserve container for an emulsion and a storage container for used emulsion, conduits to connect each of the containers with the electrode compartment and a transport unit, for example a pump, to move the emulsion.

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 fuel cell according to the present invention includes a power generation unit. The power generation unit is formed by stacking a first metal separator, a first membrane electrode assembly, a second metal separator, a second membrane electrode assembly, and a third metal separator. The number of flow grooves in a first oxygen-containing gas flow field is different from the number of flow grooves in a second oxygen-containing gas flow field. The first oxygen-containing gas flow field and the second oxygen-containing gas flow field have the same length, and the flow grooves in the first oxygen-containing gas flow field and the flow grooves in the second oxygen-containing gas flow field have the same depth.