Patent application number | Description | Published |
20080311437 | METHOD FOR FUEL CELL START-UP WITH UNIFORM HYDROGEN FLOW - A fuel cell system is provided having a fuel cell stack including a plurality of fuel cells. The fuel cell system includes an anode supply manifold in fluid communication with the plurality of fuel cells, the anode supply manifold adapted to deliver a anode supply stream to the plurality of fuel cells; an anode exhaust manifold in fluid communication with the anodes of the plurality of fuel cells, the anode exhaust manifold adapted to receive an anode exhaust stream from the plurality of fuel cells; a first valve in fluid communication with the anode supply manifold; and a second valve in fluid communication with the anode exhaust manifold. A method of starting the fuel cell system is also provided. The fuel cell system and method militates against a non-uniform distribution of the anode supply stream to the anodes of the plurality of fuel cells. | 12-18-2008 |
20080311441 | FUEL CELL SYSTEM USING CATHODE EXHAUST FOR ANODE RECIRCULATION - A system for providing fuel recirculation in a fuel cell is disclosed, wherein the system uses a cathode exhaust flow to energize a fuel recirculation pump that facilitates the fuel recirculation from an anode exhaust passage to an anode supply passage. | 12-18-2008 |
20090081490 | CLOSED-LOOP METHOD FOR FUEL CELL SYSTEM START-UP WITH LOW VOLTAGE SOURCE - A fuel cell system is provided that includes a fuel cell stack and an air compressor in communication with a cathode inlet, a hydrogen source in communication with an anode inlet, and a start-up battery adapted to power the air compressor. The start-up battery is at least one of a low-voltage battery and a high-voltage battery. A pressure sensor is in communication with the air compressor and adapted to measure a compressor outlet pressure. A power conversion module is in electrical communication with the start-up battery and the air compressor. A controller is in communication with the power conversion module and adapted to set an air compressor speed based on an available electrical energy. A closed-loop method of operating the fuel cell system at start-up is also provided, wherein an anode purge is scheduled based on an air flow rate calculated from the compressor outlet pressure and the actual speed. | 03-26-2009 |
20090081491 | Method for Fast and Reliable Fuel Cell System Start-Ups - A method for providing a fast and reliable start-up of a fuel cell system. The method uses a stack voltage response to a load to assess if hydrogen and oxygen are being sufficiently distributed to all of the fuel cells by coupling an auxiliary load to the fuel cell stack until a predetermined minimum cell voltage has been reached or a first predetermined time period has elapsed. The method then determines whether a minimum cell voltage has dropped to a first predetermined voltage and, if so, reduces the maximum power allowed to be below the first predetermined voltage value, determines whether the minimum cell voltage in the stack is below a second predetermined voltage, or determines whether the minimum cell voltage drop rate is greater than a predetermined voltage drop rate. If none of these conditions are met, the method returns to loading the stack with system components. | 03-26-2009 |
20090110966 | Method for Improving FCS Reliability After End Cell Heater Failure - A method for improving fuel cell system reliability in the event of end cell heater failure in a fuel cell stack. The method includes detecting that an end cell heater has failed. If an end cell heater failure is detected, then the method performs one or more of setting a cooling fluid pump to a predetermined speed that drives a cooling fluid through cooling fluid flow channels in the fuel cell stack, limiting the output power of the fuel cell stack or the net power of the fuel cell system, limiting the maximum temperature of the cooling fluid flowing out of the stack, turning off stack anti-flooding algorithms that may be used to remove water from reactant gas flow channels in the stack, and turning off cathode stoichiometry adjustments for relative humidity control in response to water accumulating in cathode flow channels in the fuel cell stack. | 04-30-2009 |
20090197125 | Method for Maximum Net Power Calculation for Fuel Cell System Based on Online Polarization Curve Estimation - An algorithm for determining the maximum net power available from a fuel cell stack as the stack degrades over time using an online adaptive estimation of a polarization curve of the stack. The algorithm separates the current density range of the stack into sample regions, and selects a first sample region from the far left of the estimated polarization curve. The algorithm then calculates the cell voltage for that current density sample region, and determines whether the calculated cell voltage is less than or equal to a predetermined cell voltage limit. If the calculated cell voltage is not less than the cell voltage limit, then the algorithm selects the next sample region along the polarization curve. When the calculated cell voltage does reach the cell voltage limit, then the algorithm uses that current density for the sample region being analyzed to calculate the maximum power of the fuel cell stack. | 08-06-2009 |
20090197126 | Adaptive Gain Scheduled Control for Current Limitation Based on Voltage Performance of a Fuel Cell System - A system and method for limiting the output current of a fuel cell stack as the stack degrades overtime. A look-up table identifies a predetermined voltage set-point for stack current density. A first comparator provides a voltage difference signal between the set-point and the stack voltage. The voltage difference signal is provided to a controller, such as a proportional-integral controller, that provides a current limiting signal. The current limiting signal and a current request signal are provided to a second comparator that selects which signal will be used to limit the maximum output current of the stack. A polarization curve estimator estimates parameters of the stack that will change over the life of the stack. The parameters are provided to a gain scheduler that provides gains to the controller that are based on where in the life of the stack it is currently operating. | 08-06-2009 |
20090197127 | Algorithm for Stack Current Controller Based on Polarization Curve Estimation of a Fuel Cell Stack - A method for providing a current density set-point for a fuel cell stack in response to a power request from the stack where the set-point is determined based on system parameters that identify the life and degradation of the stack. The method includes dividing a current density range of the fuel cell stack into a predetermined number of sample regions, and selecting the sample regions in order from low to high during the current set-point analysis. The method calculates an average cell voltage for the current density of the selected sample region, and stack power from the average cell voltage. The method then determines whether a power request signal is less than the stack power for the selected sample region and greater than the calculated power for the previous sample region, and if so, calculates the current density set-point at the requested power based on these values. | 08-06-2009 |
20090197155 | Online Low Performing Cell (LPC) Prediction and Detection of Fuel Cell System - A system and method for detecting and predicting low performing cells in a fuel cell stack. When the fuel cell stack is running and certain data validity criteria have been met, an algorithm collects the data, such as stack current density, average cell voltage and minimum cell voltage. This information is used to estimate predetermined parameters that define the stack polarization curve. The system defines a predetermined minimum current density that is used to identify a low performing cell. The system then calculates an average cell voltage and a minimum cell voltage at the minimum current density set-point, and calculates a cell voltage difference between the two. If the cell voltage difference is greater than a predetermined low voltage threshold and the minimum cell voltage is less than a predetermined high voltage threshold, the algorithm sets a flag identifying a potential for a low performing cell. | 08-06-2009 |
20100028728 | HUMIDIFICATION CONTROL DURING SHUTDOWN OF A FUEL CELL SYSTEM - A process for controlling the length of a purge and the purge rate of a fuel cell stack at system shut-down so as to provide the desired amount of stack humidity. The membrane humidification is measured at system shut-down by a high frequency resistance sensor that detects membrane humidification and provides the measurement to a controller. The controller controls the compressor that provides cathode input air to the fuel cell stack so that the time of the purge and the flow rate of the purge provide a desired membrane humidity for the next start-up. | 02-04-2010 |
20100143754 | SHUTDOWN STRATEGY TO AVOID CARBON CORROSION DUE TO SLOW HYDROGEN/AIR INTRUSION RATES - A fuel cell system including a fuel cell stack having a plurality of fuel cells, each of the fuel cells including an electrolyte membrane disposed between an anode and a cathode, an anode supply manifold in fluid communication with the anodes of the fuel cells, the anode supply manifold providing fluid communication between a source of hydrogen and the anodes, an anode exhaust manifold in fluid communication with the anodes of the fuel cells, and a fan in fluid communication with the anodes of the fuel cells, wherein the fan controls a flow of fluid through the anodes of the fuel cells after the fuel cell system is shutdown. | 06-10-2010 |
20100151288 | METHOD OF OPERATING A FUEL CELL SYSTEM IN STANDBY/REGENERATIVE MODE - A system and method for putting a fuel cell system in a stand-by during a system idle condition to improve system fuel efficiency. The method can include diverting the cathode airflow around the stack, reducing an airflow output from a cathode compressor to a minimum allowable set-point, opening the stack contactors to disconnect the stack from the high voltage bus and electrically isolate the stack from the rest of the system, engaging an independent load to the stack, such as end cell heaters in the stack, to suppress stack voltage, maintaining a positive pressure in the anode side of the fuel cell stack and periodically bleeding the anode into the exhaust stream. When a system power request is made removing the idle condition, the system returns to normal operation by directing the airflow back to the cathode and opening the stack contactors when an open circuit voltage is attained. | 06-17-2010 |
20110086286 | METHOD TO PERFORM ADAPTIVE VOLTAGE SUPPRESSION OF A FUEL CELL STACK BASED ON STACK PARAMETERS - A system and method for maintaining the voltage of fuel cells in the fuel cell stack below a predetermined maximum voltage. The method determines a desired voltage set-point value that defines a predetermined maximum fuel cell voltage value and uses the voltage set-point value and an average fuel cell voltage to generate an error value there-between. The method generates a minimum gross power prediction value using the modified voltage set-point value to prevent the fuel cell voltages from going above the predetermined maximum fuel cell voltage value and generating a supplemental power value based on the minimum gross power prediction value and the error value to determine how much power needs to be drawn from the stack to maintain the fuel cell voltage below the predetermined maximum voltage value. The method uses the supplemental power value to charge the battery or operate an auxiliary load coupled to the stack. | 04-14-2011 |
20110087441 | ONLINE METHOD TO ESTIMATE HYDROGEN CONCENTRATION ESTIMATION IN FUEL CELL SYSTEMS AT SHUTDOWN AND STARTUP - A system and method for estimating the amount of hydrogen and/or nitrogen in a fuel cell stack and stack volumes at system start-up and shut-down. The method defines the fuel cell stack and stack volumes as discrete volumes including an anode flow-field and anode plumbing volume, a cathode flow-field volume and a cathode header and plumbing volume. The method estimates the amount of hydrogen and/or nitrogen in the anode flow-field and anode plumbing volume, the cathode flow-field volume and the cathode header and plumbing volume when the fuel cell system is shut down, during a first stage when the hydrogen partial pressure between the anode and cathode is not in equilibrium and during a second stage when the hydrogen partial pressure between the anode and cathode is in equilibrium by considering various flows into and out of the volumes. | 04-14-2011 |
20110091780 | IN-SITU FUEL CELL STACK RECONDITIONING - A method for reconditioning a fuel cell stack. The method includes periodically increasing the relative humidity level of the cathode input airflow to the stack to saturate the cell membrane electrode assemblies to be greater than the relative humidity levels during normal stack operating conditions. The method also includes providing hydrogen to the anode side of the fuel cell stack at system shut down while the membrane electrode assemblies are saturated without stack loads being applied so that the hydrogen crosses the cell membranes to the cathode side and reacts with oxygen to reduce stack contaminants. | 04-21-2011 |
20110091781 | AUTOMATED PROCEDURE FOR EXECUTING IN-SITU FUEL CELL STACK RECONDITIONING - A method for reconditioning a fuel cell stack. The method includes determining whether fuel cell stack reconditioning is desired based on predetermined reconditioning triggers, determining if predetermined system constraints are met that will allow reconditioning of the fuel cell stack to occur, and determining whether previous reconditioning processes have been attempted, and if so, whether predetermine reconditioning limits have been exceeded during those attempts. The reconditioning process is initiated if one or more of the reconditioning triggers has occurred, the predetermined system constraints are met and the predetermined reconditioning limits have not been exceeded. The reconditioning process increases the humidification level of a cathode side of the fuel cell stack over the humidity level of the cathode side during normal operating conditions and waiting for cell membranes in the fuel cell stack to saturate after the humidification level of the cathode has increased. | 04-21-2011 |
20110143243 | FUEL CELL OPERATIONAL METHODS FOR HYDROGEN ADDITION AFTER SHUTDOWN - A method for reducing the probability of an air/hydrogen front in a fuel cell stack is disclosed that includes closing anode valves for an anode side of the fuel cell stack to permit a desired quantity of hydrogen to be left in the anode side upon shutdown and determining a schedule to inject hydrogen during the time the fuel cell stack is shutdown. The pressure on an anode input line is determined and a discrete amount of hydrogen is injected into the anode side of the stack according to the determined schedule by opening anode input line valves based on the determined pressure along the anode input line so as to inject the hydrogen into the anode side of the stack. | 06-16-2011 |
20110244348 | FEEDBACK CONTROL OF H2 INJECTION DURING PARK BASED ON GAS CONCENTRATION MODEL - A method for determining when to inject hydrogen gas into the anode side of a fuel cell stack associated with a fuel cell vehicle when the vehicle is off. The method includes estimating the concentration of hydrogen gas in the anode side of the fuel cell stack using a gas concentration model and determining if the estimated concentration of hydrogen gas is below a first predetermined threshold. If the estimated hydrogen gas is less than the threshold, then hydrogen gas is injected into the anode side from a hydrogen source. While the hydrogen gas is being injected, the method compares the estimated concentration of the hydrogen gas in the anode side to a desired concentration, and generates an error signal there between. If the error signal is greater than a second predetermined threshold, the algorithm continues to inject the hydrogen into the anode side of the fuel cell stack. | 10-06-2011 |
20110287327 | DETECTION OF SMALL ANODE LEAKS IN FUEL CELL SYSTEMS - A system and method for detecting small hydrogen leaks in an anode of a fuel cell system. The method includes determining that a shut-down sequence has begun, and if so, deplete the cathode side of a fuel cell stack of oxygen. The method then increases the pressure of the anode side of the fuel cell stack to a predetermined set-point, and monitors the pressure decay of the anode side of the stack. The method compares the rate of pressure decay to an expected pressure decay rate, and if the measured pressure decay rate exceeds the expected pressure decay rate by a certain threshold, determines that a potential leak exists. | 11-24-2011 |
20120064423 | DYNAMIC VOLTAGE SUPPRESSION IN A FUEL CELL SYSTEM - A system and method for determining a maximum average cell voltage set-point for fuel cells in a fuel cell stack that considers oxidation of the catalyst in the fuel cells. The method includes determining the average cell voltage, the stack current density (I) and an internal resistance (R) of membranes in the fuel cells to calculate an IR corrected average cell voltage. The IR corrected average cell voltage is then used to determine the oxidation state of the catalyst particles using, for example, an empirical model. The oxidation state of the particles is then used to calculate the maximum average cell voltage set-point of the fuel cells, which is used to set the minimum power requested from the fuel cell stack. | 03-15-2012 |
20130177826 | ADAPTIVE LIMITATION OF STANDBY MODE TO ENHANCE FUEL CELL SYSTEM LIFE - A system and method for reducing the frequency of stack stand-by mode events, if necessary, as a fuel cell stack ages and experiences lower performance. The method determines an irreversible voltage loss of the fuel cell stack at predetermined time intervals and determines a stack voltage degradation variable based on the irreversible voltage loss. The method also determines if the stack voltage degradation variable indicates that the fuel cell stack will not meet predetermined stack end-of-life voltage requirements and calculates a maximum allowed voltage degradation rate of the fuel cell stack. The method calculates a maximum number of stand-by mode events per unit time that can be allowed to prevent the stack from exceeding the maximum allowed degradation rate and controls the number of stand-by mode events based on the calculated maximum number of stand-by mode events. | 07-11-2013 |
20130209906 | REACTANT CONTROL METHOD FOR A FUEL CELL SYSTEM IN IDLE-STOP MODE - A system and method for controlling the reactants in anode and cathode compartments of a fuel cell stack while the fuel cell stack is in a stand-by or idle-stop mode. The method includes identifying a voltage set-point for an average voltage of the fuel cells in the fuel cell stack or an overall stack voltage that is a minimum voltage acceptable for the idle-stop mode. The actual cell voltage average or stack voltage is compared to the voltage set-point to generate a voltage error. The voltage error is provided to a controller that does one or both of providing hydrogen gas to the anode compartment of the stack to increase the anode compartment pressure, which decreases the voltage error if the voltage is above the voltage set-point, or providing more cathode air to the cathode compartment of the fuel cell stack if the voltage error is below the voltage set-point. | 08-15-2013 |
20140018975 | SYSTEMS AND METHODS FOR PREVENTING BATTERY DEPLETION IN A VEHICLE - System and methods for preventing battery depletion in a vehicle are disclosed. In certain embodiments, a method for preventing depletion of a battery included in a vehicle may include receiving a measurement of the SOC of the battery from an SOC sensor. A determination may be made as to whether the SOC of the battery has reached a threshold indicating that the battery is nearing depletion. Based on the determination, a notification may be transmitted to a remote device associated with a user of the vehicle. In certain embodiments, the user may use the notification to decide whether to remotely start a system of the vehicle to recharge the battery. | 01-16-2014 |
20140038073 | SHUTDOWN STRATEGY TO AVOID CARBON CORROSION DUE TO SLOW HYDROGEN/AIR INTRUSION RATES - A fuel cell system including a fuel cell stack having a plurality of fuel cells, each of the fuel cells including an electrolyte membrane disposed between an anode and a cathode, an anode supply manifold in fluid communication with the anodes of the fuel cells, the anode supply manifold providing fluid communication between a source of hydrogen and the anodes, an anode exhaust manifold in fluid communication with the anodes of the fuel cells, and a fan in fluid communication with the anodes of the fuel cells, wherein the fan controls a flow of fluid through the anodes of the fuel cells after the fuel cell system is shutdown. | 02-06-2014 |
20140120441 | METHOD FOR DETERMINING AN AVERAGE CELL VOLTAGE FOR FUEL CELLS - A system and method for determining a maximum average cell voltage set-point for fuel cells in a fuel cell stack that considers oxidation of the catalyst in the fuel cells. The method includes determining the average cell voltage, the stack current density (I) and an internal resistance (R) of membranes in the fuel cells to calculate an IR corrected average cell voltage. The IR corrected average cell voltage is then used to determine the oxidation state of the catalyst particles using, for example, an empirical model. The oxidation state of the particles is then used to calculate the maximum average cell voltage set-point of the fuel cells, which is used to set the minimum power requested from the fuel cell stack. | 05-01-2014 |
20140170514 | VARIABLE PEM FUEL CELL SYSTEM START TIME TO OPTIMIZE SYSTEM EFFICIENCY AND PERFORMANCE - A system and method for controlling a fuel cell system start time based on various vehicle parameters. The method includes providing a plurality of inputs that identify operating conditions of the fuel cell system and determining a maximum allowable start-time of the fuel cell system using a hybridization control strategy and the plurality of inputs. The method then determines a maximum compressor speed and ramp rate to provide the optimal allowable start-time of the fuel cell system minimizing energy consumption and noise. | 06-19-2014 |
20140363752 | SYSTEMS AND METHODS FOR CONTROLLING CABIN HEATING IN FUEL CELL VEHICLES - System and methods for controlling and optimizing coolant system parameters in a fuel cell system to obtain a requested cabin temperature in a fuel cell vehicle are presented. A method for managing a temperature in a vehicle cabin may include receiving an indication relating to a desired vehicle cabin temperature and a plurality of measured operating parameters. Based on the measured operating parameters, a projected output temperature of a cabin heat exchanger may be estimated. A determination may be made that the projected output temperature of the cabin heat exchanger is less than the indication. Based on the determination a fuel cell coolant parameter may be adjusted. | 12-11-2014 |