Abstract:
When a stop trigger of a fuel cell system (100) is turned on, air humidified by a humidifier (3) with an air humidification amount lower than during a normal operation is supplied to a fuel cell stack (1) so as to increase the water bring-out amount Qm generated in the fuel cell stack (1) when continuing a predetermined time Pg of power generation of the fuel cell stack (1). After this, power generation is stopped and the cathode side of the fuel cell stack (1) is Pp-purged by the air for a predetermined time.
Abstract:
A fuel cell system for receiving input fuel, input water and input oxidant comprising a humidifying assembly for combining the input fuel with input water to produce humidified fuel, a fuel cell having an anode for receiving the humidified fuel and a cathode for receiving the input oxidant, and a power load controller for controlling a power load on the fuel cell system based on a power output set point and changes in the detected load If the load drops from a high load to a low load and ability to ramp to a high target power output is thereafter restored, the controller is adapted to perform a rapid load recovery procedure by controlling the power output of the fuel cell system to increase from a power output corresponding to the low load to the high target power output corresponding to the high load at a first predetermined rate.
Abstract:
A power system housing (10) with an enclosure (11) is described wherein the enclosure defines a cavity (25). A subrack (30) mounted in the cavity supports a plurality of discrete proton exchange membrane fuel cell modules (100) in the cavity, and has forward (34) and rearward (35) edges, and top (35) and bottom (40) portions. An air distribution assembly (70) is received in the enclosure and coupled in fluid flowing relation relative to the top and bottom portions of the subrack. The subrack further includes an integral plenum (71), the plenum having an intake end (72) and an exhaust end (73). Coupled to the plenum are an air movement assembly (74) and an air mixing valve (80). The assembly moves the air from the intake end to the exhaust end of the plenum and the air mixing valve controls the amount of air which has passed through the respective fuel cells and which is recirculated back to each of the fuel cell modules. In addition to the air distribution assembly, a hydrogen distribution assembly is also disclosed.
Abstract:
Some embodiments of the present invention provide systems and methods for more accurately determining the cause of a particular fault in an electrochemical cell based on an impedance measurement characterizing the electrochemical cell. In some very specific embodiments the impedance of an electrochemical cell or stack is measured across a range of frequencies to determine a corresponding impedance signature characterizing the present state of the electrochemical cell or stack. By evaluating the impedance signature in comparison to reference information, a number of faults may be detected. In some more specific embodiments once a corresponding specific fault is determined and an indication is provided to a user and/or a balance-of-plant monitoring system, which may be used to adjust the operating parameters of an electrochemical cell module to compensate for and/or reverse the detrimental effects caused by a particular fault.
Abstract:
A membrane electrode diffusion assembly (150) is described comprising a solid proton conducting electrolyte membrane (151) with opposite anode (153) and cathode (154) sides. Individual catalytic anode (161) and cathode (162) electrodes formed on the proton conducting electrolyte membrane are affixed in ionic contact with a non-catalytic electrically conductive diffusion layer (170) of a given porosity.
Abstract:
The invention relates to a low-temperature fuel cell stack comprising a specific device for the supply of fuel. Said low-temperature fuel cell stack is characterised in that, in addition to the central fuel supply device, it comprises a supply or storage device for a liquid fuel, and a plurality of separately controllable dosing devices that lead into the central fuel supply device, especially respectively upstream of a distribution channel to the individual cells. Controllable valves, controllable piezoelectric pumps or thermally controllable supply elements are suitable as dosing devices. The invention also relates to a method for operating one such low-temperature fuel cell stack, which advantageously enables a defined concentration of fuel, or a defined humidity of the oxidation medium, to be adjusted at certain points in the fuel cell stack, especially on the inlet for the individual cells.
Abstract:
When a stop trigger of a fuel cell system (100) is turned on, air humidified by a humidifier (3) which air having a humidity quantity lower than a humidity quantity at a normal operation is supplied to a fuel cell stack (11). Thereby, a takeout quantity Qm of a moisture generated in the fuel cell stack (1) is increased, then, a power generation of the fuel cell stack (1) is continued for a certain time Pg. Then, the power generation is stopped, and a cathode side of the fuel cell stack (1) is purged with the air for a certain time Pp.
Abstract:
An apparatus and method for controlling humidification device turndown ratio for proton exchange membrane fuel cells includes a proton exchange membrane fuel cell, a humidifier, a water separator for directing water vapor from the proton exchange membrane fuel cell to the humidifier, a bypass valve to regulate vapor flow into the humidifier, a turbo-compressor and control valve for regulating temperature of air flow into the humidifier, and an expansion turbine for recovery of energy from the humidifier and bypass valve.
Abstract:
Disclosed is a fuel cell apparatus including a stack, a stack air blower configured to supply external air to the stack, a humidifier configured to extract moisture contained in exhaust air discharged from the stack and to supply the extracted moisture to external air supplied to the stack, a first bypass channel configured to allow exhaust air to bypass the humidifier, a first three-way valve controlled to adjust the amount of exhaust air that bypasses the humidifier, and a humidity sensor configured to sense the humidity of external air. The fuel cell apparatus further includes a second bypass channel configured to allow external air to bypass the humidifier, a second three-way valve controlled to adjust the amount of external air that bypasses the humidifier, and a controller configured to control the first three-way valve and the second three-way valve depending on the sensed humidity value of the external air.