Abstract: This specification describes a system and method for controlling the voltage produced by a fuel cell. The system involves providing a bypass line between an air exhaust from the fuel cell and an air inlet of the fuel cell. At least one controllable device is configured to allow the flow rate through the bypass line to be altered. A controller is provided to control the controllable device. The method involves varying the rate of recirculation of air exhaust to air inlet so as to provide a desired change in fuel cell voltage.

Abstract: A fuel cell including a catalyst layer configured to generate liquid water in response to a reactant being in contact therewith. The fuel cell includes a microporous layer having a first region with a first pore size and a second region disposed adjacent to the first region having a second pore size. The first pore size being greater than the second pore size. The microporous layer being configured to transfer the liquid water away from the catalyst layer, such that the liquid water from the catalyst layer enters the first region in response to a capillary pressure of the liquid water being greater than a first capillary pressure. The liquid water enters the second region in response to a capillary pressure of the liquid water being greater than a second capillary pressure. The first capillary pressure being different from the second capillary pressure.

Abstract: A sub-assembly for an electrochemical stack, such as a PEM fuel cell stack, has a bipolar plate with sealing material extending from its upper face, around the edge of the bipolar plate, and onto its lower face. The bipolar plate is preferably a combination of an anode plate and a cathode plate defining an internal coolant flow field and bonded together by sealing material which also provides a seal around the coolant flow field. All of the sealing material in the sub-assembly may be one contiguous mass. To make the sub-assembly, anode and cathode plates are loaded into a mold. Liquid sealing material is injected into the mold and fills a gap between the edge of the plates, and portions of the outer faces of the plates, and the mold. In a stack, sub-assemblies are separated by MEAs which at least partially overlap the sealing material on their faces.

Abstract: The present disclosure generally relates to a system and methods for managing and controlling emissions produced by a vehicle and/or powertrain which includes one or more power sources selected from a fuel cell, a fuel cell stack, a battery, and combinations thereof, a processor, one or more inputs, a controller, and one or more emission control devices.

Abstract: The present disclosure generally relates to systems and methods for detecting a hydrogen leak in a fuel cell system including initiating a shutdown process of a fuel cell stack in the fuel cell system by a controller, measuring a volume of hydrogen in a reservoir, pulsing a volume of hydrogen into the reservoir or pulsing hydrogen directly into the fuel cell stack if the volume of hydrogen is insufficient to sustain a voltage discharge process during the shutdown process, making the fuel cell system enter a discharge state by the controller, wherein hydrogen and oxygen in the fuel cell stack are consumed in an electrochemical reaction to discharge voltage in the fuel cell stack, measuring a rate of the voltage discharge by the controller, and detecting the hydrogen leak based on the rate of the voltage discharge or via negative pressure measurements made at the anode inlet.

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: An electrochemical cell has a membrane located between two flow field plates. On a first side of the membrane, there is a porous support surrounded by a seal between the membrane and the flow field plate. There is a gap between the porous support and the seal at the surface of the membrane. On a second side of the membrane, there is a seal between the membrane and the flow field plate located inside of the gap in plan view. The electrochemical cell is useful, for example, in high pressure or differential pressure electrolysis in which the second side of the membrane will be consistently exposed to a higher pressure than the first side of the membrane.

Abstract: An electrolyser operates within an energy system, for example to provide grid services, energy storage or fuel, or to produce hydrogen from electricity produced from renewable resources. The electrolyser may be configured to operate at frequently or quickly varying rates of electricity consumption or to operate at a specified power consumption.

Abstract: The present disclosure generally relates to a fuel cell electrode having a patterned microporous layer and method of fabricating the same.

Abstract: A system includes a fuel cell stack and a controller. The controller is configured to determine a current density of the fuel cell stack, determine a threshold voltage value, and compare a measured average fuel cell voltage value and the threshold voltage value. The controller is configured to set an allowed current and power draw of the fuel cell stack.

Abstract: A method of performing a leak check of a hydrogen supply valve of a fuel cell system includes supplying hydrogen to a fuel cell stack of the system for a predetermined time period closing the supply valve and purge valves, and opening a cathode exhaust valve. The method further includes supplying oxygen to the fuel cell stack for the predetermined time period, continuously measuring a test voltage of the fuel cell stack during the predetermined time period while oxygen is being supplied to the fuel cell stack, and determining that the hydrogen supply valve is leaking in response to the test voltage exceeding a predetermined leak voltage for the predetermined time period.

Abstract: A system includes a fuel cell engine, a plurality of switching devices, and a controller. The fuel cell engine includes a plurality of fuel cell modules connected in series as a fuel cell string, and then a plurality of these strings connected in parallel. The switching device(s) are electrically coupled to bypass when required each module(s) and or disconnect each string(s). The decision whether a module(s) and/or string(s) are bypassed, disconnected, or left to operate is based on a sensory feedback that is input into the finite state machine and fault management process that are embedded within the fuel cell controller. The bypassing scheme at the module level is handled in a manner such that the remaining modules within a series string can provide continuous, uninterrupted flow of current to the end application.

Abstract: The present disclosure relates to a thermal management system and method of adjusting and/or reversing coolant flow of a fuel cell system during stationary applications.

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: An electrochemical cell has a membrane located between two flow field plates. On a first side of the membrane, there is a porous support surrounded by a seal between the membrane and the flow field plate. There is a gap between the porous support and the seal at the surface of the membrane. On a second side of the membrane, there is a seal between the membrane and the flow field plate located inside of the gap in plan view. The electrochemical cell is useful, for example, in high pressure or differential pressure electrolysis in which the second side of the membrane will be consistently exposed to a higher pressure than the first side of the membrane.

Abstract: This specification describes a system and method for controlling the voltage produced by a fuel cell. The system involves providing a bypass line between an air exhaust from the fuel cell and an air inlet of the fuel cell. At least one controllable device is configured to allow the flow rate through the bypass line to be altered. A controller is provided to control the controllable device. The method involves varying the rate of recirculation of air exhaust to air inlet so as to provide a desired change in fuel cell voltage.

Abstract: A process for starting a PEM fuel cell module includes blowing air through the cathode side of the module using external power. An amount hydrogen is released into the anode side of the module under a pressure greater than the pressure of the air on the cathode side, while the anode is otherwise closed. Cell voltages in the module are monitored for the appearance of a charged state sufficient to start the module. When the charged state is observed, the module is converted to a running state.

Abstract: A process for starting a PEM fuel cell module includes blowing air through the cathode side of the module using external power. An amount hydrogen is released into the anode side of the module under a pressure greater than the pressure of the air on the cathode side, while the anode is otherwise closed. Cell voltages in the module are monitored for the appearance of a charged state sufficient to start the module. When the charged state is observed, the module is converted to a running state.

Abstract: An electrical power supply system has a fuel cell module and a battery. The fuel cell can be selectively connected to the battery system through a diode. The system preferably also has a current sensor and a controller adapted to close a contactor in a by-pass circuit around the diode after sensing a current flowing from the fuel cell through the diode. The system may also have a resistor and a contactor in another by-pass circuit around the diode. In a start-up method, a first contactor is closed to connect the fuel cell in parallel with the battery through the diode and one or more reactant pumps for the fuel cell are turned on. A current sensor is monitored for a signal indicating current flow through the diode. After a current is indicated, a by-pass circuit is provided around the diode.

Abstract: An electrolyser operates within an energy system, for example to provide grid services, energy storage or fuel, or to produce hydrogen from electricity produced from renewable resources. The electrolyser may be configured to operate at frequently or quickly varying rates of electricity consumption or to operate at a specified power consumption.