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-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 includes providing fuel and oxidant flows to a fuel cell. The technique includes humidifying the anode of the fuel cell, including saturating the oxidant flow and maintaining a temperature of the oxidant flow above a temperature of the fuel cell such that excess water propagates from a cathode of the fuel cell to the anode.

Abstract: A fuel cell-based system including equipment not classified to operate in a flammable environment, a detector to detect a flammable gas, and a component capable of leaking a flammable gas are arranged in an enclosure. The component is positioned above the unclassified equipment and below the sensor, and a buoyancy path is provided such that the unclassified equipment is isolated from flammable gas emitted by the component in the enclosure while a ventilation system is not energized. In addition, the detector is placed in the buoyancy path so that when the system is started from a de-energized state, the detector can determine whether an unacceptable concentration of flammable gas is present in the enclosure. When the system is energized, the ventilation system creates an air stream through the enclosure. The ventilation system is arranged such that unclassified equipment is upstream of flammable gas that is emitted by the component in the enclosure.

Abstract: A system includes a fuel cell that has an anode chamber that is in a deadheaded configuration. A controller of the system controls a valve that is connected to the anode chamber pursuant to a modulation scheme to purge the anode chamber.

Abstract: A technique includes preventing corrosion during one of start up and shut down of a fuel cell. The corrosion prevention includes controlling a load on the fuel cell during the start up/shut down to regulate a voltage of the fuel cell.

Abstract: A fuel cell system includes a first subsystem that is classified to operate in a hazardous environment and a second subsystem that is classified to operate in a hazardous environment. The second subsystem includes a sensor to detect inflammable gas, and the second subsystem is adapted to control communication of power to the first subsystem based on whether the second subsystem detects a concentration of the flammable gas exceeding a predefined threshold.

Abstract: A technique includes providing fuel and oxidant flows to a fuel cell. The technique includes humidifying the anode of the fuel cell, including saturating the oxidant flow and maintaining a temperature of the oxidant flow above a temperature of the fuel cell such that excess water propagates from a cathode of the fuel cell to the anode.

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: This application relates to a hybrid power supply apparatus comprising a fuel cell and an energy storage device for use in off-road electric vehicles, such as lift trucks. The apparatus is a substitute for conventional lead acid batteries and is sized to fit within a conventional lift truck battery receptacle tray. The fuel cell and fuel processor systems are designed to meet the average load requirements of the vehicle, while the batteries and power control hardware are capable of responding to very high instantaneous load demands. The invention has a similar electrical interface as conventional battery systems and does not require vehicle modification. The apparatus is air-cooled to ensure that the hybrid power components operate within a preferred temperature range and to maintain the external surfaces of the apparatus and exhaust gases within safe temperature limits.

Abstract: This application relates to a hybrid power supply apparatus including a fuel cell and an energy storage device for use in off-road electric vehicles, such as lift trucks. The apparatus is a substitute for conventional lead acid batteries and is sized to fit within a conventional lift truck battery receptacle tray. The fuel cell and fuel processor systems are designed to meet the average load requirements of the vehicle, while the batteries and power control hardware are capable of responding to very high instantaneous load demands. The invention has a similar electrical interface as conventional battery systems and does not require vehicle modification. The apparatus is air-cooled to ensure that the hybrid power components operate within a preferred temperature range and to maintain the external surfaces of the apparatus and exhaust gases within safe temperature limits.

Abstract: This application relates to an energy storage device protection circuit for use in a hybrid system supplying power to an active dynamic DC load, such as an electric vehicle drive. The circuit prevents over-discharge of the energy storage device and ensures that the system will be capable of delivering a minimum acceptable level of power to the load, even when the energy storage device is in a low state of charge or other de-rated mode. The hybrid system includes a power generator such as fuel cell capable of supplying at least the average power value requirements of the load and an energy storage device such as a battery or capacitor capable of supplying at least the difference between the peak power requirements of the load and the average power value. A controller is provided for controlling the relative supply of power to the load from the power generator and the energy storage device.

Abstract: This application relates to a method and system for controlling the supply of fuel to a dead-ended hydrogen fuel cell. The invention may be utilized, for example, to more efficiently integrate the operation of a hydrogen fuel cell and a hydrogen generator, such as a reformer coupled with a hydrogen separation unit. The invention ensures that the production and consumption of hydrogen are effectively balanced to avoid negative feed line pressure fluctuations. The fuel supply control subsystem and hydrogen consumption control subsystems are, however, “decoupled” and hence independently operable. The invention may include an accumulator disposed in a flow path between the hydrogen generator and the fuel cell for storing hydrogen under pressure. The accumulator is sufficiently large in volume such that the pressure of hydrogen in the flow path does not deviate substantially from a target pressure, even during the waste purging sessions.

Abstract: This application relates to cast enclosures for battery replacement applications, such as enclosures configured to house power units comprising a fuel cell and an energy storage device. The enclosures function as protective enclosures and counterweights, provide mounting points and conduits for gases, fluids, plumbing and wiring, and serve as thermal energy storage/transfer devices. The enclosures are formed in a mold or die and comprise wall portions defining a plurality of internal subcompartments for receiving the various system components. In one embodiment of the invention channels may be formed in the wall portions of the enclosures for circulating a heat transfer fluid therethrough.

Abstract: A cell voltage monitoring device is powered internally by the stack being measured and uses no external power sources whatsoever. The cell voltage monitoring device comprises a plurality of differential amplifiers each corresponding to a cell within the stack. The differential amplifiers are divided into groups of a suitable number, each group corresponding to a set of series-connected cells being collectively measured by the differential amplifiers in that group. Within each group of differential amplifiers, the positive supply terminal of each differential amplifier is connected to the most positive output terminal of the corresponding set of series-connected cells, and the negative supply terminal of each differential amplifier is connected to the most negative output terminal of the corresponding set of series-connected cells. By doing so, each group of differential amplifiers is powered by the set of series-connected cells being measured by that group.

Abstract: This application relates to a hybrid power supply apparatus comprising a fuel cell and an energy storage device for use in off-road electric vehicles, such as lift trucks. The apparatus is a substitute for conventional lead acid batteries and is sized to fit within a conventional lift truck battery receptacle tray. The fuel cell and fuel processor systems are designed to meet the average load requirements of the vehicle, while the batteries and power control hardware are capable of responding to very high instantaneous load demands. The invention has a similar electrical interface as conventional battery systems and does not require vehicle modification. The apparatus is air-cooled to ensure that the hybrid power components operate within a preferred temperature range and to maintain the external surfaces of the apparatus and exhaust gases within safe temperature limits.

Abstract: This application relates to a method and system for controlling the supply of fuel to a dead-ended hydrogen fuel cell. The invention may be utilized, for example, to more efficiently integrate the operation of a hydrogen fuel cell and a hydrogen generator, such as a reformer coupled with a hydrogen separation unit. The invention ensures that the production and consumption of hydrogen are effectively balanced to avoid negative feed line pressure fluctuations. The fuel supply control subsystem and hydrogen consumption control subsystems are, however, “decoupled” and hence independently operable. The invention may include an accumulator disposed in a flow path between the hydrogen generator and the fuel cell for storing hydrogen under pressure. The accumulator is sufficiently large in volume such that the pressure of hydrogen in the flow path does not deviate substantially from a target pressure, even during the waste purging sessions.

Abstract: This application relates to a system and method for regulating the temperature of a self-contained fuel cell apparatus preferably comprising a fuel reformer. The invention maintains the various components of the fuel cell apparatus within preferred operating temperature ranges while ensuring that exhaust gases and external surfaces of the apparatus do not exceed safe temperature levels. The invention is particularly suited for self-contained hybrid power supply applications, for example for non-road electric vehicles. The various components of the apparatus are strategically configured relative to air flow paths to fully utilize the cooling capacity of the process stream and minimize parasitic loads. In some embodiments the inlet air is pre-heated to enable operation of the apparatus in low temperature environments, such as industrial freezers.

Abstract: A system and method for improving the performance of a hybrid power supply apparatus comprising a power generating device, such as a fuel cell, and a primary energy storage device, such as a battery. The purpose of the invention is to provide an equalization charge to the battery from a source other than the fuel cell when the battery achieves a predetermined state of charge condition, thereby avoiding the need to operate the fuel cell in a low power output mode. When the predetermined state of charge condition is detected by a controller, the fuel cell is shut-down. In one aspect of the invention the equalization charge is provided to the battery by a secondary energy storage device, such as a plurality of capacitors or secondary batteries. The predetermined state of charge condition may be satisfied, for example, when the state of charge of the battery exceeds a predetermined threshold, such as 80% of the battery's storage capacity, for a predetermined period of time.

Abstract: This application relates to a hybrid power supply apparatus comprising a fuel cell and an energy storage device for use in off-road electric vehicles, such as lift trucks. The apparatus is a substitute for conventional lead acid batteries and is sized to fit within a conventional lift truck battery receptacle tray. The fuel cell and fuel processor systems are designed to meet the average load requirements of the vehicle, while the batteries and power control hardware are capable of responding to very high instantaneous load demands. The invention has a similar electrical interface as conventional battery systems and does not require vehicle modification. The apparatus is air-cooled to ensure that the hybrid power components operate within a preferred temperature range and to maintain the external surfaces of the apparatus and exhaust gases within safe temperature limits.