Abstract: A fuel cell system that generates electricity using an electrochemical reaction of fuel gas and oxidizing gas, having: a pressure adjustment valve which is provided on a fuel gas supply path for conducting the fuel gas from a fuel gas supply source to a fuel cell and which adjusts the supply gas pressure of the fuel gas; a degree of opening adjustment valve provided downstream of the pressure adjustment valve on the fuel gas supply path, the degree of opening thereof being set in stages or continuously in accordance with a degree of opening signal; and control means that adjusts the degree of opening adjustment signal in accordance with the operating condition of the fuel cell system and controls the state quantity of fuel gas supplied to the fuel cell to a target quantity.

Abstract: A gas control and operation method of a fuel cell system for improved water and gas distribution is disclosed. The present invention provides for a mechanization of a fuel cell system that allows control of the anode reactant and anode effluent through the anode portions of the fuel cell system to improve water and gas distribution on the anode side of the fuel cells that increases the voltage stability of the fuel cells.

Abstract: The fuel cell system is provided which detects a freeze among specific components and portions thereof by evaluating various conditions upon starting operation of the fuel cell system. If a freeze is detected through those evaluations, the start of the system is prohibited in order to prevent some deterioration in the fuel cell system.

Abstract: A technique includes operating a fuel cell, which produces an effluent flow. The technique includes routing the effluent flow through an electrochemical pump to extract fuel from the effluent flow to produce a first feedback flow. The technique includes using the effluent flow to produce a second feedback flow separate from the first feedback flow and routing the second feedback flow through a venturi to the fuel cell.

Abstract: A PEM fuel cell (4) power plant includes a passive air vent (24) through which air separated from a cathode effluent stream can be expelled from the power plant. The air vent operates satisfactorily during ambient freezing conditions thus it is eminently suitable for use in mobile applications such as in PEM fuel cell-powered automobiles, buses, or the like. The vent is formed from a liquid antifreeze layer (40) that is disposed in a sparging tank (36) which communicates with ambient surroundings. Any water vapor in the stream can condense out of the gas-stream in the antifreeze. In order to facilitate this result, the antifreeze can be a liquid that is immiscible with water so that the condensed water will form a separate layer (38) in the sparging tank.

Abstract: Fuel concentration near a power generator of a DMFC is adjusted by decreasing current taken from the DMFC when the concentration near the power generator of the DMFC is higher than an optimum value and increasing the current taken from the DMFC when the concentration near the power generator of the DMFC is lower than the optimum value. Since the fuel does not come into direct contact with the power generator in the DMFC in a portion from a cartridge to the power generator in the DMFC, drying of the fuel is suppressed. By providing an auxiliary tank capable of storing fuel, concentration of methanol supplied near the power generator of the DMFC is lowered upon activation after long-time storage.

Abstract: A power generator is formed with a container adapted to hold a hydrogen generating fuel. A valve assembly has a valve plate with a border less than a border of the container. A fuel cell is laterally disposed outside and around the valve assembly having a lateral width that fits within the border of the container. A cover is adapted to mate with the container and enclose the valve plate and fuel cell.

Abstract: A fuel cell system may include a cathode loop having an operating pressure during fuel cell system operation. The cathode loop may include a normally open mechanical check valve disposed at a water pooling location within the loop and having a cracking pressure approximately equal to the operating pressure.

Abstract: A fuel cell stack that includes a stack of fuel cells each having a cathode side bipolar plate including parallel cathode gas flow channels. Airflow from a cathode inlet manifold is directed to the flow channels to provide the cathode gas to the fuel cell membrane. The fuel cell stack includes a device positioned within the inlet manifold that selectively blocks a predetermined number of the flow channels for each cell at low load operation to increase the flow rate in the unblocked flow channels, so that the fuel cell stack generates the desired low load output, and the increased flow rate prevents water from accumulating in the unblocked flow channels.

Abstract: A method of operating a fuel cell (1) in which a gaseous supply stream (5) comprising a reactive species is delivered to an electrode (2) where the reactive species is consumed in an electrochemical reaction to produce an exhaust stream (7, 8) which is depleted in reactive species, which method comprises: a) assessing the concentration of reactive species in the exhaust stream (7, 8); b) relating the concentration of reactive species in the exhaust stream (7, 9) to a maximum current that may be drawn from the fuel cell (1) without redox damage of the electrode; and c) adjusting the way in which the fuel cell (1) is operated in order to optimize efficiency without redox damage of the electrode (2).

Abstract: A controllable range of an air flow rate and an air pressure in a fuel cell system is calculated from air flow rates and air pressures when the air back pressure valve is fully open and fully closed. A target generation current is calculated from an accelerator position or an auxiliary unit to calculate a target air flow rate and a target air pressure as target values. If the target values are outside the controllable range, it is judged whether the target values exceed an upper limit the controllable range, the target values are decreased onto the upper limit, and if no, the target values are increased onto the lower limit of the controllable range.

Abstract: A portable electricity generation device comprises a plurality of fuel cells, each fuel cell having an anode end with a catalyst facilitating the separation of hydrogen atoms into electrons and protons, a cathode end facilitating the combination of the electrons and protons into water molecules in the presence of oxygen, and a current bearing portion providing a current path for the electrons to traverse. The electricity generation device also includes a fuel storage container for storing a supply of hydrogen and delivering the supply of hydrogen to an anode end of the plurality of fuel cells so as to initiate a flow of the electrons through the current bearing portion. In addition, the portable electricity generation device includes an air moving device configured to direct atmospheric air toward a cathode end of the plurality of fuel cells, wherein the air moving device is positioned to convectively cool the plurality of fuel cells as it supplies atmospheric air to the cathode end.

Abstract: A direct oxidation fuel cell (DOFC) system, comprises at least one fuel cell assembly including a cathode and an anode with an electrolyte positioned therebetween; a source of liquid fuel in fluid communication with an inlet of the anode; an oxidant supply in fluid communication with an inlet of the cathode; a liquid/gas (L/G) separator in fluid communication with outlets of the anode and cathode for: (1) receiving unreacted fuel and liquid and gaseous products, and (2) supplying a solution of fuel and liquid product to the anode inlet; and a control system for measuring the amount of liquid product and controlling oxidant stoichiometry of the system operation in response to the measured amount of liquid product. Alternatively, the control system controls the concentration of the liquid fuel in the solution supplied to the anode inlet, based upon the system operating temperature or output power.

Abstract: A vehicle power plant includes a high temperature PEM fuel cell system operatively connected to a battery pack. A power conditioner is operatively connected between the PEM fuel cell system and the battery pack. The system can include a fuel processor, such as a steam reformer or an autothermal reformer. The reformer can be designed such that it can reform a wide range of fuels. The system can provide for a vehicle with a much higher driving range at a potentially lower cost than an equivalent range battery-only electric vehicle. The integration of these components into a single system also allows the vehicle to be fuel flexible; that is, capable of being fueled with a wide range of fuels without hardware changes in the system.

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

Abstract: A fuel cell-based system includes an electromechanical pressure relief system to prevent an overpressure condition from damaging the anode circuit of a fuel cell stack or creating a hazardous environment. Upon detection of a fuel flow pressure in a fuel path between a fuel source and the fuel cell stack, the pressure relief system isolates the anode circuit from the fuel path, vents the fuel flow, and shuts down the fuel cell system.

Abstract: A fuel cell system (50) includes pressure obtaining means (4) for obtaining the pressure in a hydrogen system (anode (1b)) of a fuel cell (1), pressure estimation means (10) for estimating the hydrogen partial pressure in the hydrogen system. Further, the fuel cell system (50) includes impurity concentration estimation means (10) for estimating the impurity concentration in the hydrogen system. That is, the impurity concentration estimation means (10) estimates the impurity concentration taking the present state of the hydrogen system into consideration. Thus, the impurity concentration estimation means (10) accurately estimates the impurity concentration in the hydrogen system of the fuel cell (1).

Abstract: For a fuel cell system, the flow rate and the pressure of the air flow supplied to the cathode side are controlled with the following procedure. First, air is supplied to the cathode at the flow rate and supply pressure required for generating electricity. In this state, the changing rate of the amount of formed water accumulated in the cathode is estimated based on the required electricity generation and the air flow rate. When the accumulated amount of formed water increases in a high rate, to avoid flooding, the cathode outlet regulation valve is intermittently opened to decrease the outlet gas pressure. Also, at a frequency less than that of the pressure decrease, the air flow rate is increased. By executing this operation, the increased air flow rate and the pressure difference between the cathode inlet and outlet, it is possible to promote discharge of the formed water with small loss of energy.

Abstract: A flux control apparatus includes an outlet pressure detector for detecting an outlet pressure of a fluid at an outlet of a fluid flow apparatus driven by a drive source for feeding the fluid from an inlet of the fluid flow apparatus and letting the fluid flow out from the outlet of the fluid flow apparatus, a drive amount detector for detecting an amount of drive of the drive source, an estimated flux-calculating apparatus for calculating a flux of the fluid flowing from the fluid flow apparatus as an estimated flux on the basis of the pressure of the fluid and the amount of drive, a control amount-calculating apparatus for calculating an amount of control for the fluid flow apparatus on the basis of the estimated flux and a target flux, and a control apparatus for controlling the drive source on the basis of the amount of control.

Abstract: A water generation system for the generation of water on board an aircraft comprises a fuel cell device having an exhaust for an exhaust gas, a condenser and an outflow valve for discharging cabin air, which is drawn off through the condenser due to the pressure difference between the cabin pressure and ambient pressure without extensive cooling circuits or pumps, for example. The condenser may be coupled to the exhaust such that the exhaust gas is cooled by cabin air, and the outflow valve is connected to the condenser and to the environment of the aircraft, such that, when the aircraft is at cruising altitude, the cabin air is drawn through the condenser and is discharged into the environment.

Abstract: The present disclosure is directed to a fuel cell component having a cathode that includes a lanthanum manganate material as well as channels for receiving a flow of oxygen, and a buffer layer extending along the channels through which oxygen flows. The fuel cell component also includes an anode having channels for receiving a flow of fuel and an electrolyte layer disposed between the cathode and the anode.

Abstract: The present invention provides a fuel cell power system and a power generating method in which the rise of concentration of water vapor and carbon dioxide in the direction of the anode gas flow is controlled to enhance the electromotive force in the downstream region of the anode gas flow, thereby improving the power generating efficiency. A mixed gas of a hydrocarbon and water vapor and/or carbon dioxide or a reformed version of said mixed gas having an oxygen atom/carbon atom ratio (O/C ratio) of 2 or higher is supplied from a spot upstream in the direction of the anode gas flow while a hydrocarbon or a mixed gas of a hydrocarbon and water vapor and/or carbon dioxide having an O/C ratio of lower than 2 is supplied supplementally from a spot downstream, and the gas supplied supplementally from the downstream side is reformed by making use of water vapor and carbon dioxide generated by the electrochemical reactions upstream of the anode gas flow and is utilized for power generation.

Abstract: The invention relates to a method for operating a direct oxidation fuel cell in which at least one fluid fuel is transported from a fuel reservoir via a fluid distribution structure to a membrane electrode assembly, the transport of the fuel being effected passively, i.e. without convection. Furthermore, the invention relates to a corresponding direct oxidation fuel cell.

Abstract: The present invention provides a method for supplying fuel to a fuel cell, in which a monitoring period is determined for monitoring the fuel cell, and then a feeding amount of fuel is determined by integrating characteristic value generated from the fuel cell in the monitoring period. In another embodiment, it is further comprising a step of determining the variation profile associated with the characteristic value during the period so as to judge whether it is necessary to feed the fuel into the fuel cell or not. By means of the present invention, the supplying of fuel to the fuel cell under dynamic loadings can be effectively controlled for optimizing the performance of the fuel cell as well as reducing the cost without installing any fuel sensor.

Abstract: A fuel cell system comprising: an anode gas circulation path comprising an anode gas supplying path and an anode gas ejection path; a fuel cell; a blowdown valve; and a control unit controlling the blowdown valve, wherein the control unit comprises a freeze estimation unit estimating whether the anode gas circulation path is likely to freeze, a pressure reduction unit reducing a pressure of the anode gas circulation path, and a pressure condition confirmation unit confirming a pressure of the anode gas circulation path; and when the freeze estimation unit estimates a freezing when the fuel cell stops generating electricity, the blowdown valve is closed, a pressure of the anode gas circulation path is reduced by the pressure reduction unit, and, the blowdown valve is opened after the pressure condition confirmation unit confirms that a pressure of the anode gas circulation path reaches a predetermined pressure less than or equal to an atmospheric pressure, thereby moving a moisture inside the anode gas circula

Abstract: A fuel cell-based system includes an electromechanical pressure relief system to prevent an overpressure condition from damaging the anode circuit of a fuel cell stack or creating a hazardous environment. Upon detection of a fuel flow pressure in a fuel path between a fuel source and the fuel cell stack, the pressure relief system isolates the anode circuit from the fuel path, vents the fuel flow, and shuts down the fuel cell system.

Abstract: A technique for heating a fuel cell stack at stack start-up that includes using the vehicle motor drive system to generate waste heat independent from providing traction. Particularly, at fuel cell stack start-up, the electric traction inverter associated with the traction motor that drives the vehicle is controlled so that command signals provided by an inverter to a traction motor do not provide motor torque, but dissipates power into the motor windings and/or motor structure as waste heat. Thus, the output power generated by the fuel cell stack can be made high enough to quickly heat the fuel cell stack through inefficiencies in the stack operation, without providing driving torque. Additionally, the electric traction inverter can be operated so that waste heat is generated within the semiconductor power switches in the inverter.

Abstract: A control apparatus for a fuel cell stack includes a fuel cell stack having a stacked body formed by stacking fuel cell units together and a pair of end plates sandwiching the stacked body therebetween; electrical heaters disposed near the ends of the stacked body or the end plates, respectively; a water purging device for purging water which is generated during a power generation operation in the fuel cell stack, and which is held in the fuel cell units; and a control unit which controls the power generation operation in the fuel cell stack, and which is operatively connected to the electrical heaters and the water purging device. The control unit is adapted to operate the electrical heaters and the water purging device when the power generation operation is stopped.

Abstract: A fuel cell system is described that enables discharge of moisture generated by the fuel cell system based on pressure differences between components of the fuel cell system. The fuel cell system includes a fuel cell that discharges oxidant offgas via a cathode discharge pipe and discharges fuel offgas and moisture to an anode drain opening that in turn discharges the fuel offgas and the moisture to a gas-liquid separator via an anode drainpipe. A throttle valve establishes a pressure difference downstream within the anode drainpipe to enable movement of the fuel offgas and the moisture from the anode drain opening to a lower pressure area of the gas-liquid separator. In addition, the pressure difference enables the fuel offgas to flow from the gas-liquid separator to the cathode discharge pipe through the throttle valve.

Abstract: A fuel cell system which includes: a fuel cell fed with a reaction gas for generating power; an output detection unit which detects output current and voltage of the fuel cell; a storage unit which stores a standard current-voltage characteristic of the fuel cell, from which a standard voltage of the fuel cell at an output current thereof is obtainable; and a gas feed mismatch detection unit which detects a gas feed mismatch of the reaction gas, based on a comparison between the detected output voltage of the fuel cell and the standard voltage at the detected output current, obtained from the standard current-voltage characteristic stored.

Abstract: A method of operating a fuel cell assembly and a fuel cell system use a simple construction to restrain deterioration of power generating performance of a fuel cell assembly at a startup in a subfreezing environment. If an ignition switch is turned off is STEP 1, a control unit determines in STEP 3 whether the temperature of a fuel cell assembly (the internal temperature of the fuel cell assembly) is lower than a predetermined temperature, which is higher than the temperature at which the water produced during power generation freezes. If the internal temperature of the fuel cell assembly is the predetermined temperature or higher, then the processing proceeds to STEP 4 wherein a power generating condition is adjusted to cause the internal temperature of the fuel cell assembly to rise. In STEP 5, an alarm device is actuated.

Abstract: Embodiments relate to a fuel cell system. In an embodiment, the fuel cell system includes advanced leak test capabilities. In another embodiment, the fuel cell system includes a system to bypass one or more separation units while permitting the fuel cell system to continue to produce electricity. In another embodiment, the fuel cell system includes an alignment system that permits ease of alignment when a fuel cell module is installed proximate a fuel processing module. In another embodiment, the fuel cell system includes a system of supplying auxiliary fuel from a mobile auxiliary fuel supply. In an embodiment, one or more or all of these embodiments may be practiced together in combination.

Abstract: A method of starting a fuel cell stack in subzero conditions that minimizes start times while avoiding cell reversal by using an iterative model to determine the optimal current density time profile for startup.

Abstract: According to an aspect of the invention, a diagnostic apparatus which diagnoses a state of the fuel cell includes an operation device which is used for operating the fuel cell; an operational state detecting portion which detects a change in an operational state of the fuel cell; a device control portion which controls the operation device such that the fuel cell is operated according to at least one predetermined operation pattern; and a diagnostic portion which diagnoses the state of the fuel cell based on the change in the operational state of the fuel cell that is detected by the change in the operational state detecting portion when the fuel cell is operated by the device control portion according to the at least one predetermined operation pattern, and the at least one predetermined operation pattern.

Abstract: The present invention relates to a recharging valve for an electrical power generator. The electrical power generator includes one or more fuel cells, a housing, surrounding the one or more fuel cells, a sleeve contacting at least a portion of an outer surface of the housing, a fuel chamber enclosing a hydrogen generating fuel, and one or more recharging valves, in contact with the fuel chamber. The recharging valves provide a means for safe and rapid recharging the hydrogen generating fuel.

Abstract: A fuel cell stack (1) performs power generation using an anode gas having hydrogen as its main component, and after a power generation reaction, the anode gas is discharged as anode effluent. The anode effluent is re-circulated into the anode gas through a return passage (5). The return passage (5) comprises a purge valve (8) which discharges the anode effluent to the outside of the passage. In this invention, calculation of a first energy loss caused by an increase in non-hydrogen components in the anode gas while the purge valve (8) is closed (S7, S28), and calculation of a second energy loss which corresponds to the amount of hydrogen lost from the anode gas by opening the purge valve (8) (S8, S29) are performed. By opening the purge valve (8) when the second energy loss equals or falls below the first energy loss, the start timing of purging is optimized.

Abstract: A fuel cell system includes a fuel cell stack; a diluted fuel tank for storing diluted fuel; a diluted fuel conduit for supplying the diluted fuel from the fuel dilution tank to the fuel cell stack; a differential pressure sensor in the diluted fuel conduit to sense a differential pressure resulting from a fuel flow inside the diluted fuel conduit and to transmit an electric signal; and a controller for receiving the electric signal from the differential pressure sensor and for determining whether or not fuel is flowing inside the diluted fuel conduit.

Abstract: Embodiments may include efficient fuel cell systems including an anode, a cathode, a lead-containing cathode catalyst, at least one proton exchange connector, and perhaps even an external circuit between the anode and the cathode. Other embodiments may include enhanced degradation of contaminants in environmental media such as perhaps petroleum hydrocarbon in groundwater with microbial fuel cells and the like.

Abstract: A gas-liquid separation system includes a housing at which a gas inlet and a gas outlet are provided; a separation pipe contained in the housing; a separation membrane provided in the separation pipe; and a pump configured to inject a gas into the housing through the gas inlet from an outside of the housing to the gas outlet.

Abstract: The present invention provides geometric arrangements for channels through which liquids or other fluids can be made to flow, for enhanced performance of fuel cells or other chemical or biochemical reactors or analyzers. Systems and methods including these improved geometries are described herein for enhanced performance of a variety of devices. Specifically, in one set of embodiments, the reactors comprise one or more microchannels comprising a tapered cross-sectional area and at least one reactive surface portion. By flowing a liquid comprising one or more reactants through the channel such that the cross-sectional area decreases in a downstream direction, relatively more reactant may be supplied to the wall at downstream positions relative to the amount that would be supplied in a system without a tapered cross-section. In some embodiments, the microchannel may be constructed and arranged such that the amount of reactant supplied to the wall conforms to a predetermined distribution.

Abstract: A compartmentalized storage tank is disclosed. The compartmentalized storage tank includes a housing, a first fluid storage section disposed within the housing, a second fluid storage section disposed within the housing, the first and second fluid storage sections being separated by a movable divider, and a constant force spring. The constant force spring is disposed between the housing and the movable divider to exert a constant force on the movable divider to cause a pressure P1 in the first fluid storage section to be greater than a pressure P2 in the second fluid storage section, thereby defining a pressure differential.

Abstract: A method of operating a fuel cell stack is disclosed. The method includes operating the fuel cell stack in accordance with a predetermined profile of fuel gas/oxidant gas delta pressure vs. time, monitoring a fuel gas/oxidant gas delta pressure vs. time value of the fuel cell stack and adjusting pressure of the fuel gas by consuming excess quantities of the fuel gas in the fuel cell stack when the fuel gas/oxidant gas delta pressure vs. time value of the fuel cell stack exceeds the predetermined profile.

Abstract: A fuel cell system enables time required for purging to be reduced without a major increase in discharge gas concentration at a time of purging. It comprises a fuel cell; a fuel gas supply path for supplying the fuel gas to an anode; an oxidizing gas supply path for supplying an oxidizing gas to a cathode; a fuel gas circulating path for returning an unreacted fuel gas to an anode inlet side; a dilution box for diluting the fuel gas by the oxidizing gas and for discharging it to outside; and a fuel gas discharge path connecting the fuel gas circulating path and a dilution box discharge gas inlet. A drain valve, a purge valve and an air discharge valve are provided, opening areas of which are different from one another. The drain valve with a smallest opening area is initially opened.

Abstract: The present invention is a fuel cell system including a fuel cell, an injector which is provided in a hydrogen supply channel of the fuel cell and which adjusts a gas state of an upstream side of the hydrogen supply channel to supply a gas toward a downstream side, and a control device which drives and controls the injector. The control device controls an operation of the injector based on a driving state of an associated device including the fuel cell system 1.

Abstract: A controlled-clearance sealing compressor device that provides precision rotor centering directly with respect to the stator housing, vane centering with respect to rotor (not the stator) and the dynamic balance design of the gliders required for practical single and dual vane devices. The devices uses roller bearings to control the radial position of the vane and control rods or pins are used to control axial positioning of the vane, its ‘centralization’ with respect to the rotor and the endplates. The positive displacement rotary vane compressors and vacuum pumps have friction reduction, efficiency enhancement and exceedingly long operating life as a result of the non-contact gas sealing of the process gas within the rotary vane compressors and vacuum pumps. In an embodiment the positive displacement compressing device is used in transportation vehicles.

Abstract: The present invention provides a method for controlling the amount of air supplied to a fuel cell, which can prevent flooding and membrane dry-out in a fuel cell stack and, at the same time, ensure optimal performance of the fuel cell stack and a humidifier by supplying an optimal amount of air to the fuel cell stack at each operation condition. For this purpose, the present invention provides a method for controlling the amount of air supplied to a fuel cell, the method including measuring the temperature and pressure of humidifier outlet (stack inlet) air, the temperature and pressure of stack outlet air, and the relative humidity of the humidifier outlet (stack inlet) air, and determining the stoichiometric ratio of air or the amount of air supplied to the stack based on the measurement results so as to adjust the relative humidity of the stack outlet air reach a target value.

Abstract: A fuel cell power plant (10) includes a power supply (58) that directs a direct current to catalysts (24), (26) of a fuel cell (22) after terminating flow of electricity to a primary load (52), and after flow of an oxidant adjacent the cathode catalyst (26) is terminated, and while a reformate fuel is directed adjacent the anode catalyst (24). Pure hydrogen fuel generated thereby at the cathode catalyst (26) is directed into a hydrogen storage tank (62). Upon start-up of the power plant (10), the stored hydrogen gas is directed from the tank (62) to flow adjacent the anode catalyst (24) while a reformer (12) is being warmed up for operation, to provide virtually instantaneous start-up of the plant (10). Optionally, the stored hydrogen may be used occasionally during operation with the reformate fuel to meet an increased demand for electricity.

Abstract: Fuel cell systems and methods for controlling the operation of components of the fuel cell system, such as which may include a fuel source and a fuel cell stack. In some examples, a fuel source is adapted to provide supply fuel to a fuel cell stack at a supply pressure. In some systems, fuel not used by the fuel cell stack is discharged through at least one exit orifice at an exit pressure. In some examples, a control system is adapted to control operation of one or both of the fuel source and the fuel cell stack based on the flow of unused fuel. In some examples, a target pressure is determined based on the level of electrical current produced by a fuel cell stack, such that when fuel is supplied at the target pressure, the fuel cell stack consumes a given proportion of the supply fuel.

Abstract: A fuel cell system comprises a fuel cell stack, a cell voltage monitor, a hydrogen tank, a hydrogen supply channel, an ejector, a hydrogen off-gas channel, a purge valve, a compressor, an air supply channel, a pressure control unit for controlling air pressure, a pilot pressure input channel branching off from the air supply channel and inputting the air pressure to the ejector as pilot pressure, and a control unit for controlling the purge valve and the pressure control unit. The ejector includes a pressure control mechanism which increases the ejector's secondary-side pressure by increasing the area of the nozzle's ejecting hole when the pilot pressure input from the pilot pressure input channel rises. When electricity generation status of the fuel cell stack is judged to be poor, the control unit opens the purge valve after raising the air pressure and the pilot pressure by using the pressure control unit.

Abstract: A portable electricity generation device comprises a plurality of fuel cells, each fuel cell having an anode end with a catalyst facilitating the separation of hydrogen atoms into electrons and protons, a cathode end facilitating the combination of the electrons and protons into water molecules in the presence of oxygen, and a current bearing portion providing a current path for the electrons to traverse. The electricity generation device also includes a fuel storage container for storing a supply of hydrogen and delivering the supply of hydrogen to an anode end of the plurality of fuel cells so as to initiate a flow of the electrons through the current bearing portion. In addition, the portable electricity generation device includes an air moving device configured to direct atmospheric air toward a cathode end of the plurality of fuel cells, wherein the air moving device is positioned to convectively cool the plurality of fuel cells as it supplies atmospheric air to the cathode end.