Abstract: A fuel cell system that determines the phase transition from water to gas through a bleed/drain valve in a water separation device. The fuel cell system includes a fuel cell stack having an anode side and a cathode side. An injector injects hydrogen gas into the anode side of the fuel cell stack. The water separation device receives an anode exhaust gas from the anode side of the fuel cell stack, where the water separation device includes a water holding reservoir. A controller controls the injector and the bleed/drain valve and determines when the bleed/drain valve transitions from draining water to bleeding the anode exhaust gas by comparing the flow rate through the water separation device and the flow rate through the injector.

Abstract: A product comprising a fuel cell component comprising a substrate and a coating overlying the substrate, the coating comprising nanoparticles having sizes ranging from 2 to 100 nanometers.

Abstract: A product comprising a fuel cell component comprising a substrate and a coating overlying the substrate, the coating comprising nanoparticles having sizes ranging from 2 to 100 nanometers.

Abstract: A method for determining the amount of fuel flow from a high pressure gas tank to the anode side of a fuel cell stack through pulsed injector. The anode sub-system pressure is measured just before the injector pulse and just after injector pulse and a difference between the pressures is determined. The difference between the pressures, the volume of the anode sub-system, the ideal gas constant, the anode sub-system temperature, the fuel consumed from the reaction in the fuel cell stack during the injection event and the fuel cross-over through membranes in the fuel cells of the fuel cell stack are used to determine the amount of hydrogen gas injected by the injector.

Abstract: A fuel cell system that employs an injector/ejector for providing fresh hydrogen and anode recirculation gas to the anode side of a fuel cell stack. The injector/ejector is operated with a variable frequency so that the injector open time at low stack current densities is long enough to allow a pressure drop to be provided in the anode flow channels to push out water that may have accumulated therein. In one embodiment, the injector/ejector control provides a minimum pulse width per cycle and a maximum frequency so that as the stack current density decreases below a certain value the frequency decreases from the maximum frequency to maintain the pulse width constant at the minimum pulse width.

Abstract: A method for determining a failure of a membrane in a fuel cell in a fuel cell stack. The method includes measuring the voltage of each fuel cell in the fuel cell stack, calculating an average cell voltage from all of the cell voltages of the fuel cells in the fuel cell stack, and identifying a minimum cell voltage from all of the cell voltages of the fuel cells in the fuel cell stack. The method then determines an absolute delta voltage value as the difference between the average cell voltage of the fuel cells and the minimum cell voltage of the fuel cells at a plurality of sample points during the sample period. A plurality of absolute delta voltage values determined over a plurality of sample periods, filtered for low current density are used to determine whether there is a membrane failure and, by filtering for high current density, to determine whether there is an electrode failure.

Abstract: An ejector for a fuel cell stack is disclosed, wherein the ejector includes an integrated check valve that supports hydrogen recirculation and militates against a backflow of hydrogen flowing through the ejector.

Abstract: A fuel cell system including a humidification system is described. The humidification system employs a recycling system that recycles relatively humid gas exhausted from a multistage fuel cell stack, either on the anode and/or cathode side, and sends this relatively humid gas back to be combined with relatively dry supply gas, such as but not limited to hydrogen and/or air. The humidified supply gas mixture is then reintroduced into the first stage of the multistage fuel cell stack. A recirculation device, such as but not limited to a pump and/or an ejector, can be used to aid in moving the humid exhaust gas back through a recycle gas line to be combined with the supply gas.

Abstract: A fuel cell system that determines the phase transition from water to gas through a bleed/drain valve in a water separation device. The fuel cell system includes a fuel cell stack having an anode side and a cathode side. An injector injects hydrogen gas into the anode side of the fuel cell stack. The water separation device receives an anode exhaust gas from the anode side of the fuel cell stack, where the water separation device includes a water holding reservoir. A controller controls the injector and the bleed/drain valve and determines when the bleed/drain valve transitions from draining water to bleeding the anode exhaust gas by comparing the flow rate through the water separation device and the flow rate through the injector.

Abstract: A method for determining a failure of a membrane in a fuel cell in a fuel cell stack. The method includes measuring the voltage of each fuel cell in the fuel cell stack, calculating an average cell voltage from all of the cell voltages of the fuel cells in the fuel cell stack, and identifying a minimum cell voltage from all of the cell voltages of the fuel cells in the fuel cell stack. The method then determines an absolute delta voltage value as the difference between the average cell voltage of the fuel cells and the minimum cell voltage of the fuel cells at a plurality of sample points during the sample period. A plurality of absolute delta voltage values determined over a plurality of sample periods, filtered for low current density are used to determine whether there is a membrane failure and, by filtering for high current density, to determine whether there is an electrode failure.

Abstract: A fuel cell system that employs an injector/ejector for providing fresh hydrogen and anode recirculation gas to the anode side of a fuel cell stack. The injector/ejector is operated with a variable frequency so that the injector open time at low stack current densities is long enough to allow a pressure drop to be provided in the anode flow channels to push out water that may have accumulated therein. In one embodiment, the injector/ejector control provides a minimum pulse width per cycle and a maximum frequency so that as the stack current density decreases below a certain value the frequency decreases from the maximum frequency to maintain the pulse width constant at the minimum pulse width.

Abstract: A method for determining the amount of fuel flow from a high pressure gas tank to the anode side of a fuel cell stack through pulsed injector. The anode sub-system pressure is measured just before the injector pulse and just after injector pulse and a difference between the pressures is determined. The difference between the pressures, the volume of the anode sub-system, the ideal gas constant, the anode sub-system temperature, the fuel consumed from the reaction in the fuel cell stack during the injection event and the fuel cross-over through membranes in the fuel cells of the fuel cell stack are used to determine the amount of hydrogen gas injected by the injector.

Abstract: A fuel cell system wherein a plurality of fuel cells are arranged in a series of stages, the number of fuel cells decreasing in number in each stage from anode gas inlet to the anode gas outlet. The system allows for parallel flow to all of the cells in a given stage and series flow between the various stages. A similar configuration is present on a cathode side of the system. However, the direction of flow is reversed, providing a greater number of cells in the stage nearest the cathode outlet and a fewer number of cells in the stage near the cathode gas inlet. The invention further provides for the various stages to be configured such that the direction of flow of the anode gas of a given stage is generally opposite the direction of flow of the cathode gas of a given stage.

Abstract: An ejector for a fuel cell stack is disclosed, wherein the ejector includes an integrated check valve that supports hydrogen recirculation and militates against a backflow of hydrogen flowing through the ejector.

Abstract: A method of fuel cell stack humidification is provided incorporating the use of an accumulation device. The method provides for feeding back humid anode exhaust gas of the fuel cell stack to the fuel cell inlet and switching the anode inlet and outlet of the fuel cell stack for achieving better homogeneity of humidity along the fuel cell channels.

Abstract: A fuel cell system including a humidification system is described. The humidification system employs a recycling system that recycles relatively humid gas exhausted from a multistage fuel cell stack, either on the anode and/or cathode side, and sends this relatively humid gas back to be combined with relatively dry supply gas, such as but not limited to hydrogen and/or air. The humidified supply gas mixture is then reintroduced into the first stage of the multistage fuel cell stack. A recirculation device, such as but not limited to a pump and/or an ejector, can be used to aid in moving the humid exhaust gas back through a recycle gas line to be combined with the supply gas.

Abstract: A fuel cell system wherein a plurality of fuel cells are arranged in a series of stages, the number of fuel cells decreasing in number in each stage from anode gas inlet to the anode gas outlet. The system allows for parallel flow to all of the cells in a given stage and series flow between the various stages. A similar configuration is present on a cathode side of the system. However, the direction of flow is reversed, providing a greater number of cells in the stage nearest the cathode outlet and a fewer number of cells in the stage near the cathode gas inlet. The invention further provides for the various stages to be configured such that the direction of flow of the anode gas of a given stage is generally opposite the direction of flow of the cathode gas of a given stage.

Abstract: A method of fuel cell stack humidification is provided incorporating the use of an accumulation device. The method provides for feeding back humid anode exhaust gas of the fuel cell stack to the fuel cell inlet and switching the anode inlet and outlet of the fuel cell stack for achieving better homogeneity of humidity along the fuel cell channels.

Abstract: A method of fuel cell stack humidification is provided incorporating the use of an accumulation device. The method provides for feeding back humid anode exhaust gas of the fuel cell stack to the fuel cell inlet and switching the anode inlet and outlet of the fuel cell stack for achieving better homogeneity of humidity along the fuel cell channels.

Abstract: A method of fuel cell stack humidification is provided incorporating the use of an accumulation device. The method provides for feeding back humid anode exhaust gas of the fuel cell stack to the fuel cell inlet and switching the anode inlet and outlet of the fuel cell stack for achieving better homogeneity of humidity along the fuel cell channels.