Abstract: A fuel cell stack hydrogen starvation detection device, a fuel cell system and a method of operating a fuel cell stack to protect it from hydrogen starvation conditions. In one particular form, the fuel cell system includes a stack of fuel cells, a controller and a detection device made up of one or more sensors that can compare a reference signal corresponding to the presence of substantially pure hydrogen to a signal that corresponds to a local hydrogen value within a single fuel cell within the stack or across multiple fuel cells within the stack. In this way, the detection device promptly provides indicia of a hydrogen starvation condition within the cell or stack without the need for conventional cell voltage monitoring. The detected hydrogen starvation condition may be presented as a warning signal to alert a user that such a condition may be present, as well as to the controller for modification of the stack operation.

Abstract: A method for controlling a pressure drop across the anode side or the cathode side of a fuel cell stack by controlling the intrusion of a cell separator into the flow channels in a feeder region of the stack so as to create a larger pressure volume on a pressure bias side of the stack. The method controls the flow rates of one or both of the cathode and anode reactant gases so as to cause the cell separators in an inlet feeder region and/or an outlet feeder region to move relative to the anode side and the cathode side so as to change a flow volume in the inlet feeder region and/or the outlet feeder region to control the pressure drop.

Abstract: A system and method for determining the purity level of hydrogen gas fuel provided to an anode side of a fuel cell stack, and then modifying models and algorithms used by the system based on the purity level. The method includes determining whether predetermined criteria have been met that are necessary to obtain an accurate hydrogen gas fuel purity level, and if so, comparing a measured voltage or current of the fuel cell stack to a modeled voltage or current of the fuel cell stack. If the comparison between the measured voltage or current and the modeled voltage or current is greater than a predetermined threshold, then the method adapts a hydrogen gas concentration value to a lower purity level to be used by downstream models.

Abstract: Systems and methods of the present disclosure include supplying a porous substrate, heating the porous substrate to produce a pre-heated substrate, applying an electrode ink to the pre-heated substrate to produce a coated substrate, and drying the electrode ink of the coated substrate to produce an electrode on the porous substrate. The pre-heated substrate has a temperature greater than 23° C. The applying occurs via a coating mechanism. The electrode ink includes a catalyst and an ionomer dispersed in a solvent. The drying occurs via a drying mechanism.

Abstract: Disclosed are fuel cell stack break-in procedures, conditioning systems for performing break-in procedures, and motor vehicles with a fuel cell stack conditioned in accordance with disclosed break-in procedures. A break-in method is disclosed for conditioning a membrane assembly of a fuel cell stack. The method includes transmitting humidified hydrogen to the anode of the membrane assembly, and transmitting deionized water to the cathode of the membrane assembly. An electric current and voltage cycle are applied across the fuel cell stack while the fuel cell stack is operated in a hydrogen pumping mode until the fuel cell stack is determined to operate at a predetermined threshold for a fuel cell stack voltage output capability. During hydrogen pumping, the membrane assembly oxidizes the humidified hydrogen, transports protons from the anode to the cathode across the proton conducting membrane, and regenerates the protons in the cathode through a hydrogen evolution reaction.

Abstract: Disclosed are fuel cell architectures, thermal sub-systems, and control logic for regulating fuel cell stack temperature. A method is disclosed for regulating the temperature of a fuel cell stack. The method includes determining a pre-start temperature of the fuel cell stack, and determining, for this pre-start temperature, a target heating rate to heat the stack to a calibrated minimum operating temperature. The method then determines a hydrogen bleed percentage for the target heating rate, and executes a stack heating operation including activating the fuel cell stack and commanding a fluid control device to direct hydrogen to the cathode side at the hydrogen bleed percentage to generate waste heat. After a calibrated period of time, the method determines if an operating temperature of the stack exceeds the calibrated minimum stack operating temperature. Responsive to the operating temperature being at or above the minimum operating temperature, the stack heating operation is terminated.

Abstract: A fuel cell system includes a fuel cell stack and a controller. The fuel cell stack includes a catalyst and a stack voltage. The controller increases efficiency of the fuel cell stack by minimizing or removing an accumulation of oxides on the catalyst during a low-power operating mode of the fuel cell system. The controller executes a method for dynamically controlling the stack voltage during a detected low-power operating mode. The method includes commanding low-voltage/high-power pulses to the fuel cell stack via the controller at a magnitude and frequency sufficient for minimizing or removing the oxides. The system may include a direct current-direct current (DC-DC) boost converter, with the controller programmed to command the power pulses from the DC-DC boost converter. Or, the controller may be configured to command the power pulses by controlling a feed rate of the oxygen and/or the hydrogen.

Abstract: A method for controlling a pressure drop across the anode side or the cathode side of a fuel cell stack by controlling the intrusion of a cell separator into the flow channels in a feeder region of the stack so as to create a larger pressure volume on a pressure bias side of the stack. The method controls the flow rates of one or both of the cathode and anode reactant gases so as to cause the cell separators in an inlet feeder region and/or an outlet feeder region to move relative to the anode side and the cathode side so as to change a flow volume in the inlet feeder region and/or the outlet feeder region to control the pressure drop.

Abstract: Disclosed are fuel cell stack break-in procedures, conditioning systems for performing break-in procedures, and motor vehicles with a fuel cell stack conditioned in accordance with disclosed break-in procedures. A break-in method is disclosed for conditioning a membrane assembly of a fuel cell stack. The method includes transmitting humidified hydrogen to the anode of the membrane assembly, and transmitting deionized water to the cathode of the membrane assembly. An electric current and voltage cycle are applied across the fuel cell stack while the fuel cell stack is operated in a hydrogen pumping mode until the fuel cell stack is determined to operate at a predetermined threshold for a fuel cell stack voltage output capability. During hydrogen pumping, the membrane assembly oxidizes the humidified hydrogen, transports protons from the anode to the cathode across the proton conducting membrane, and regenerates the protons in the cathode through a hydrogen evolution reaction.

Abstract: A method and system for manufacturing a corrosion resistant performs the steps of: (1) providing a substrate; (2) moving the substrate to a cleaning chamber via the conveyor; (3) cleaning the substrate; (4) moving the substrate into a first pressure chamber; (5) moving the substrate out of the first pressure chamber; (5) determining a first temperature change in the substrate at the first pressure chamber; (6) adjusting a second heat source at a second pressure chamber based on the first temperature change; and (7) moving the substrate into the second pressure chamber. The system includes at least one pressure chamber housing a heat source wherein a temperature sensor is disposed at the inlet and at the outlet of the pressure chamber. A control unit may be in communication with the temperature sensors and the heat sources.

Abstract: A flow field plate for a fuel cell includes an electrically conductive substrate at least partially defining a plurality of flow channels. A carbon layer is disposed over the flow field plate. The carbon layer includes graphene, carbon nanotubes, or combinations thereof and has a thickness less than about 10 nanometers. Chemical vapor deposition and atomic layer deposition processes for forming graphene layers on a flow field plate are also described.

Abstract: Systems and methods for initiating voltage recovery procedures in a fuel cell system based in part on an estimated specific activity over the life of a fuel cell catalyst are presented. In certain embodiments, SA loss of catalyst and electrochemical surface area loss of a FC system may be estimated. An output voltage of the FC system may be estimated based on the estimated SA loss and the electrochemical surface area loss. An amount of recoverable voltage loss may be determined based on a comparison between the estimated output voltage and a measured output voltage. Based on the determined amount of recordable voltage loss, a FC system control action (e.g., a voltage recovery procedure) may be initiated.

Abstract: A fuel cell flow field plate includes an aluminum substrate plate having a first side and a second side wherein the first side of the aluminum substrate plate defines a plurality of channels for transporting a first fuel cell reactant gas. The flow field plate also includes a first metal interlayer deposited on the first side of the aluminum substrate plate, a second metal interlayer deposited on the second side of the aluminum substrate plate, a first amorphous carbon layer deposited on the first metal interlayer, and a second amorphous carbon layer deposited on the second metal interlayer. The first amorphous carbon layer and second amorphous carbon layer each independently have a density greater than or equal to 1.2 g/cc.

Abstract: Systems and methods for improving conditions for anion contaminant removal in a cathode of a PEMFC system are presented. A fuel cell system consistent with certain embodiments may include a cathode compartment having a compressor coupled thereto. The compressor may be configured to receive an input cathode gas via a compressor input and supply the input cathode gas to the cathode compartment via a compressor output. The fuel cell system may further include a cathode gas recirculation value coupled to the cathode compartment configured to receive a cathode exhaust gas output and to selectively provide at least a portion of the cathode exhaust gas output to the compressor input. Consistent with certain embodiments disclosed herein, the compressor may be further configured to supply at least a portion of the cathode exhaust gas output to the cathode compartment via the compressor output.

Abstract: A method for making corrosion resistant carbon nanoparticles includes a step of heating a carbon powder to a predetermined temperature. The carbon powder includes carbon particles having an average spatial dimension from about 10 to 100 nanometers. The carbon powder is contacted with a vapor of a metal-containing compound. The carbon powder is then contacted with a vapor of an activating compound. These steps are repeated plurality of times to form a metal-containing layer on the carbon particles.

Abstract: System and methods for reducing carbon corrosion in a fuel cell system are presented. Particularly, the disclosed systems and methods may be utilized in connection with preventing the formation of a propagating H2-Air interface within the fuel cell system. In certain embodiments, the disclosed systems and methods may utilize an electrochemical pump disposed in a cathode loop of the fuel cell system configured to remove oxygen that intrudes into the fuel cell system. In further embodiments, pumps may be included in an anode and a cathode loop of the fuel cell system that may allow for circulation of certain gases to prevent the formation of an H2-Air front with the system.

Abstract: A method for reducing fuel cell voltage loss in a fuel cell that includes an anode catalyst layer including an anode catalyst and a cathode catalyst layer including a cathode catalyst with a proton exchange layer interposed between the anode catalyst layer and the cathode catalyst layer. The method includes a step of initiating shutdown of the fuel cell. Carbon monoxide or carbon monoxide-like species contaminating the anode catalyst is oxidized during shutdown such that carbon monoxide or carbon monoxide-like species is removed from the anode catalyst.

Abstract: A fuel cell system that includes a component for removing anionic contaminants is provided. The fuel system including a fuel cell stack, a fuel gas feed subsystem in communication with fuel cell anodes in the fuel cell stack, an oxygen-containing gas feed subsystem system in communication with fuel cell cathodes in the fuel cell stack, and an anionic scavenging subsystem in communication with the fuel gas feed subsystem and/or the an oxygen-containing gas feed subsystem.

Abstract: Systems and methods for initiating voltage recovery procedures in a fuel cell system based in part on an estimated specific activity over the life of a fuel cell catalyst are presented. In certain embodiments, SA loss of catalyst and electrochemical surface area loss of a FC system may be estimated. An output voltage of the FC system may be estimated based on the estimated SA loss and the electrochemical surface area loss. An amount of recoverable voltage loss may be determined based on a comparison between the estimated output voltage and a measured output voltage. Based on the determined amount of recordable voltage loss, a FC system control action (e.g., a voltage recovery procedure) may be initiated.

Abstract: Systems and methods are disclosed that provide for a fuel cell stack assembly including stack end cells that facilitate improved diagnostic and detection capabilities. In certain embodiments, an anode side of a FC stack end cell consistent with embodiments disclosed herein may be configured to have a lower anode gas flow rate than other cells in the FC stack. The cathode side of a FC stack end cell consistent with embodiments disclosed herein may be further configured to have a higher gas flow rate than other cells in the FC stack. Embodiments of the disclosed FC stack end cells may, among other things, allow for detection of adverse conditions and/or events in a FC stack assembly prior to such conditions and/or events negatively affecting other cells in the FC stack.