Patent application number | Description | Published |
20080241608 | METHOD OF STARTING UP A FUEL CELL UNDER CONDITIONS IN WHICH WATER MAY FREEZE - A method including starting a fuel cell stack and generating heat in the fuel cell stack to raise the fuel cell stack temperature above 0° C. for each start to eliminate ice in the fuel cell stack before shutdown. | 10-02-2008 |
20090068535 | FUEL CELL BIPOLAR PLATE EXIT FOR IMPROVED FLOW DISTRIBUTION AND FREEZE COMPATIBILITY - A fuel cell assembly is disclosed that utilizes a water transport structure extending from fuel cell plates of the assembly into fuel cell assembly manifolds, wherein the water transport structure facilitates the transport of liquid water from the fuel cell plates thereby minimizing the accumulation of liquid water and ice in the fuel cell stack. | 03-12-2009 |
20090104476 | FUEL CELL STACK WITH ASYMMETRIC DIFFUSION MEDIA ON ANODE AND CATHODE - The present invention provides a fuel cell having a first diffusion and a second diffusion media having a membrane electrode assembly disposed therebetween. The first diffusion media includes a first set of material characteristics and the second diffusion media includes a second set of material characteristics. The first set of material characteristics has at least one material characteristic substantially different from those same material characteristics of the second set of material characteristics. The difference in material characteristics provides for enhancing water management across a major face of the second diffusion media. | 04-23-2009 |
20090117432 | Water Removal Features for PEMFC Stack Manifolds - A bipolar plate includes angled facets oriented to form V-shaped projections on the plate edge. Liquid leaving the reactant channels is drawn back into the V-shaped grooves of the projections, leaving no liquid to obstruct the channel exit openings. The bipolar plate includes one portion of the bipolar plate offset from another portion of the bipolar plate so as to expose the reactant channels. The liquid is drawn toward the end portions of the reactant channels by capillary forces, while the gas flows can exit near the beginning of the offset portion. A fuel cell stack includes angled facets that are rotated to lie in the plane of the bipolar plate edges. The edges are chamfered so the channel exit openings of the reactant channels are at the tip portions thereof, thus allowing the liquid to flow away from the channel exit openings and the gas to exit freely. | 05-07-2009 |
20090117443 | Bipolar Plate Hydrophilic Treatment for Stable Fuel Cell Stack Operation at Low Power - A flow field plate or bipolar plate for a fuel cell that includes a hydrophilic coating formed on flow field channels extending through a tunnel region between a cell active area and the inlet and outlet manifolds. The flow field plates are an assembly of a cathode side unipolar plate and an anode side unipolar plate. The hydrophilic coating is deposited on the unipolar plates prior to the unipolar plates being assembled into the flow field plate so that line of site deposition processes can be used to coat the flow field channels in the tunnel region. The unipolar plates can be any suitable fuel cell unipolar plates, such as stamped unipolar plates or composite unipolar plates. | 05-07-2009 |
20090142632 | FUEL CELL STACK FEATURES FOR IMPROVED WATER MANAGEMENT - An electric insulator for a fuel cell stack with a plurality of fuel cell plates is provided. The electric insulator includes an insulation layer having a water management feature adapted to militate against liquid water contacting the fuel cell plates. Fuel cell stacks having the water management feature are also described. | 06-04-2009 |
20090186253 | Bipolar Plate Design for Passive Low Load Stability - A fuel cell that includes a flow field plate having flow channels, where the flow channels include one enlarged stability flow channel for each set of a predetermined number of smaller flow channels. The stability channel provides a higher volume of flow therethrough, which prevents the accumulation of water at low loads. | 07-23-2009 |
20100190076 | TWO STAGE, HFR-FREE FREEZE PREPARATION SHUTDOWN STRATEGY - A system and method for providing a fuel cell stack purge at fuel cell system shut-down. The method provides a two-stage purge process where the first stage purge uses humidified cathode air to get the fuel cell stack to a known stack hydration level from an unknown stack hydration level at system shut-down. As the stack is purged with the humidified air, the hydration level of the stack decreases asymptotically to the known stack hydration level where the duration of the first stage is set based on the asymptote as a safety margin. Once the known hydration level is achieved, then the second stage purge is performed with dry air to further reduce the stack hydration to a final desired hydration level. | 07-29-2010 |
20100190078 | SHUTDOWN STRATEGY FOR ENHANCED WATER MANAGEMENT - A system and method for providing a fuel cell stack purge to remove excess water during system shut-down. A compressor is operated at a shut-down speed to force water out of the cathode flow channels and draw water through the membrane from the anode flow channels so that a desired amount of water is removed from the fuel cell stack without over drying the membrane. The cathode shut-down purge flow can be introduced in the forward or reverse direction. Further, the flow of hydrogen fuel can be directed so that it flows through the anode flow channels in an opposite direction to push water out of an anode outlet manifold into the anode flow channels so that it will also be drawn through the membrane by the cathode airflow. Finally, a brief rehydration step is added after the shut-down purge to achieve the desired water content in the cells. | 07-29-2010 |
20100227230 | ANODE WATER SEPARATOR FOR A FUEL CELL SYSTEM - An anode reactant recycling system for a fuel cell is disclosed, the system including a hollow main body, a bleed conduit, an injector, a water separator, and a hydrophilic porous media. The anode reactant recycling system for a fuel cell is adapted to minimize a required number of components, eliminate the need for the anode heat exchanger, use a single valve for removal of condensate and reactant byproducts from the anode reactant recycling system, and provide an upstream volume for startup pressurization. | 09-09-2010 |
20110138883 | INJECTOR FLOW MEASUREMENT FOR FUEL CELL APPLICATIONS - 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. | 06-16-2011 |
20110159404 | Polyolefin Support to Prevent Dielectric Breakdown in PEMS - A fuel cell includes a first catalyst layer and a second catalyst layer. An ion conducting membrane is interposed between the first and second catalyst layers. The ion conducting layer includes a polyolefin support structure and an ion conducting polymer at least partially penetrating the polyolefin support structure. A set of electrically conducting flow field plates are in communication with the first and second catalyst layers. | 06-30-2011 |
20120178010 | FUEL CELL STACK WITH ASYMMETRIC DIFFUSION MEDIA ON ANODE AND CATHODE - The present invention provides a fuel cell having a membrane electrode assembly disposed between a first diffusion media that has a first set of material characteristics and a second diffusion media that has a second set of material characteristics. The membrane electrode assembly and the first and second diffusion media provide a cell assembly. The cell assembly provides a water transport mechanism that selectively controls water transportation across a thickness of the first and second diffusion media and through the membrane electrode assembly. The first set of material characteristics has at least one material characteristic substantially different from at least one material characteristic of the second set of material characteristics. The selection of the first and second set of material characteristics defines the water transport mechanism for managing hydration of the first and the second diffusion media. | 07-12-2012 |
20120255366 | METHOD TO DETECT GROSS LOSS IN COOLANT BASED ON CURRENT FEEDBACK FROM THE HIGH TEMPERATURE PUMP - A system and method for determining a loss of cooling fluid from a thermal sub-system in a fuel cell system. The method includes monitoring current feedback from a high temperature pump that pumps the cooling fluid through a coolant loop. A measured current from the pump is compared to an expected current for the system operating conditions, and if that current is significantly less than what is expected, then it may be as a result of low cooling fluid. If the measured current is less than the expected current for a predetermined period of time, then the system can take mitigating action as a result of a low cooling fluid. Further, if the pump speed is too low to provide an accurate current measurement, then it can be increased if an overflow tank level sensor indicates a low cooling fluid level. | 10-11-2012 |
20120270118 | ANODE WATER SEPARATOR FOR A FUEL CELL SYSTEM - An anode reactant recycling system for a fuel cell is disclosed, the system including a hollow main body, a bleed conduit, an injector, a water separator, and a hydrophilic porous media. The anode reactant recycling system for a fuel cell is configured to minimize a required number of components, eliminate the need for the anode heat exchanger, use a single valve for removal of condensate and reactant byproducts from the anode reactant recycling system, and provide an upstream volume for startup pressurization. | 10-25-2012 |
20120308904 | FUEL CELL SYSTEM HAVING A FLUID FLOW DISTRIBUTION FEATURE - A fuel cell system includes a water vapor transfer unit and a fluid flow distribution feature, the water vapor transfer unit including a first plate having a plurality of first flow channels for receiving a flow of a first fluid therein, and a second plate having a plurality of second flow channels for receiving a flow of a second fluid therein. The fluid flow distribution feature is configured to control at least one of a volume of flow of the first fluid through the first flow channels and a volume of flow of the second fluid through the second flow channels, wherein at least one of a flow distribution of the first fluid across the first plate and a flow distribution of the second fluid across the second plate is varied. | 12-06-2012 |
20120321979 | CONTROL STRATEGY TO PREVENT UNEXPECTED HYDROGEN FLOW TO THE CATHODE DUE TO A FAILED PRESSURE SENSOR WHILE CATALYTIC HEATING - A method for determining a flow of a gas through an injector and a flow of a gas through a valve in a fuel cell system. The method includes determining an injector flow estimation for the gas flowing through the injector and determining a valve flow estimation for the gas flowing through the valve. The method also includes calculating an error that is a difference between the injector flow estimation and the valve flow estimation and adjusting the flow of the gas through the valve based on the error. | 12-20-2012 |
20130089797 | ANODE PURGE AND DRAIN VALVE STRATEGY FOR FUEL CELL SYSTEM - A combined water drain and diluent gas purge valve routes fluid from the anode side of a fuel cell to the cathode inlet. When a purge of diluent gas is requested, the valve opens, draining any liquid present in the sump of a water separation device, for example. After the liquid has drained, the diluent gas is purged. An anode bleed model using fuel injector feedback can determine the amount of gas exiting the valve, and can request the valve to close once the required amount of diluent is purged. During operation, an amount of hydrogen may exit the valve. Hydrogen passing through the valve can be catalytically consumed once it reaches the cathode electrode, causing the cathode exhaust, and the fuel cell exhaust to have a reduced hydrogen content. | 04-11-2013 |
20130115540 | FUEL CELL OPERATION WITH A FAILED OPEN INJECTOR - A system and method for controlling hydrogen gas flow to an anode side of a fuel cell stack using a pressure regulator in the event that an injector that normally injects the hydrogen gas into the fuel cell stack has failed in a stuck open position. During normal operation, the control of the injector is determined based on the pressure of an anode sub-system and the position of the pressure regulator is determined based on a supply pressure between the pressure regulator and the injector. If it is determined that the injector is stuck in an open position, then the position of the pressure regulator is controlled to the anode pressure instead of the supply pressure. If the pressure regulator is an electrical pressure regulator, then it is pulsed to mimic normal system operation. Alternately, another valve, such as a shut-off valve, can be employed to provide the flow pulsing. | 05-09-2013 |
20130122389 | FUEL CELL BIPOLAR PLATE EXIT FOR IMPROVED FLOW DISTRIBUTION AND FREEZE COMPATIBILITY - A fuel cell assembly is disclosed that utilizes a water transport structure extending from fuel cell plates of the assembly into fuel cell assembly manifolds, wherein the water transport structure facilitates the transport of liquid water from the fuel cell plates thereby minimizing the accumulation of liquid water and ice in the fuel cell stack. | 05-16-2013 |
20140026633 | EXTREMUM SEEKING ALGORITHM IN A VARIABLE TIME INTERVAL TO DETECT ANODE PRESSURE SENSOR STUCK FAILURE IN A FUEL CELL SYSTEM - A system and method for detecting an anode pressure sensor failure in a fuel cell system. The system and method include a controller that sets an initial minimum anode pressure sensor value and an initial maximum anode pressure sensor value. The controller determines a desired time interval for sampling anode pressure measurements and determines a total number of samples of anode pressure measurements to be collected by the controller from an anode pressure sensor. The controller also compares a pressure difference between the initial or a measured minimum anode pressure and the initial or a measured maximum anode pressure to a predetermined pressure difference threshold and sets a pressure sensor fault if the pressure difference between the initial or measured minimum anode pressure and the initial or maximum anode pressure is less than the predetermined pressure difference threshold. | 01-30-2014 |
20140033801 | DIAGNOSING INJECTOR FAILURE VIA STACK VOLTAGE RESPONSE ANALYSIS - A system and method for determining whether an anode injector that injects hydrogen gas into an anode side of a fuel cell stack has failed. The method includes monitoring a voltage of the fuel cell stack and performing spectral analysis of the stack voltage to identify amplitude peaks in the stack voltage. The method further includes determining whether the spectral analysis of the stack voltage has identified an amplitude peak at a location where an amplitude peak should occur if the injector is operating properly. If no amplitude peak is identified at that location, then the method determines that the injector is not operating properly. If an amplitude peak is identified at that location, then the method compares the amplitude peak to the desired amplitude peak to identify if it is within a threshold to determine if the injector is operating properly. | 02-06-2014 |
20140120440 | COOLANT FLOW PULSING IN A FUEL CELL SYSTEM - Systems and methods to control the delivery of coolant to a coolant loop within a vehicular fuel cell system. During periods of low power output from one or more fuel cell stacks, operation of a pump used to circulate coolant through the loop is intermittent, thereby reducing pump usage during such times. The frequency of pump operation, as measured by a pump on/off (i.e., pulsed) cycle, may be adjusted to keep a local temperature rise within the one or more stacks to no more than a small amount over the bulk stack temperature. | 05-01-2014 |
20140162159 | METHOD FOR RUNNING A FUEL CELL SYSTEM WITH A FAILED STACK HEALTH MONITOR - A system and method for selectively operating a fuel cell stack in response to loss of a voltage signal from one or more fuel cells in the stack. If the voltage signal from the one or more fuel cells is lost, the method performs one or more remedial actions to cause the fuel cell stack to operate in a more stack safe condition. The method then determines whether the cell or cells whose voltage signal is lost was healthy, such as operating above a predetermined voltage threshold, prior to the voltage signal being lost. If the cell voltage signal was above the voltage threshold, then the fuel cell stack is operated normally under the remedial actions, and if the voltage signal is below the voltage threshold, then the fuel cell stack is operated in a power limitation mode. | 06-12-2014 |
20140162171 | ANODE LEAK LOCATION DETECTION - A system and method for quantifying an anode leak location in a fuel cell system. The system and method include determining there is a leak in an anode sub-system of a fuel cell stack and estimating a first effective leak area using a first leak flow value and first operating parameters. The system and method also include increasing airflow to a cathode side of the fuel cell stack and estimating a second leak effective area using a second leak flow value and second operating parameters. The system and method further include comparing the first leak effective area to the second leak effective area and determining an anode outflow leak location based on the comparison between the first and second leak effective areas. | 06-12-2014 |
20140220468 | SYSTEM AND METHOD FOR COOLING A FUEL CELL-POWERED VEHICLE - A fuel cell system, including a plurality of bipolar plate assemblies, each assembly including a first plate and a second plate with an internal coolant flow path disposed therebetween, a flow path for a first reactant gas on a side of the first plate opposite the internal coolant flow path, and a flow path for a second reactant gas on a side of the second plate opposite the internal coolant flow path, and a cooling system configured to place coolant in thermal communication with the plurality of bipolar plate assemblies, wherein cycling pressure differentials between the internal coolant flow path and the external reactant gas flow paths cause expansion and contraction of a volume of coolant disposed within the bipolar plate assembly, thereby pumping coolant through the cooling system. A method of cooling a fuel cell-powered vehicle is also provided. | 08-07-2014 |
20140335432 | SYSTEMS AND METHODS FOR ESTIMATING FUEL CELL STATES - Apparatus, methods, and systems for estimating hydrogen concentration and/or pressure in an anode compartment of a fuel cell stack in a fuel cell vehicle. In some implementations, the estimates are based on a correlation between a transient dip in voltage in response to an anode to cathode bleed event and a concentration of hydrogen in the anode compartment of a fuel cell stack. Some implementations may comprise initiating a bleed event, sensing a transient dip in voltage in response to the bleed event, and using the correlation to calculate an estimate of a concentration and/or pressure of the gas in the anode compartment. The sensitivity of the correlation and hence the accuracy of estimation may change with the power level and may be accounted for in the correlation. | 11-13-2014 |