Abstract: A control method of a cooling water pump of fuel cell vehicle is provided. The method includes comparing a derived temperature value, including a cooling water temperature of a fuel cell or an estimated temperature of a stack of the fuel cell, with predetermined temperature criteria and comparing a required output value of the stack of the fuel cell with predetermined output criteria. The cooling water pump is then operated in a normal mode when the derived temperature value is greater than the temperature criteria or when the required output value is greater than the output criteria. Additionally, the cooling water pump is operated in a stop mode when the derived temperature value is less than the temperature criteria and, simultaneously, when the required output value is less than the output criteria.

Abstract: An electronic apparatus using a fuel cell as at least one electric power source. The fuel cell has an electric power output unit for outputting an electric power through a chemical reaction between fuel gas and oxidant gas, a purge device for purging the electric power output unit and a purge control unit for issuing a purge instruction to the purge device. The electronic apparatus has a monitor unit for monitoring a consumption power, an operation state or a manipulated state of the electronic apparatus, and a purge permission unit for judging from an output of the monitor unit whether the purge control unit is permitted to issue the purge instruction, and outputting a judgment result to the purge control unit.

Abstract: The control unit of the fuel cell system monitors the status of power generation of the fuel cell and calculates a total amount of the fuel gas consumption, based on the amount of power generated by the fuel cell, from a point in time when the supply gas pressure reaches a standard gas pressure. Another total amount of the fuel gas consumption is calculated based on a gas pressure change that corresponds to a decrease of the gas pressure from the standard gas pressure. Comparing two total amounts of the fuel gas consumptions, the evaluation is performed as whether the on-off valve in the fuel gas flow path from each of the fuel gas tanks to the fuel cell fails to be opened.

Abstract: A system and method of controlling fuel cell system is provided that simultaneously drains condensation and purges hydrogen via single valve. In particular, condensate water is drained by opening a drain-purge valve at a point in time at which a production amount of the condensate water exceeds a capacity of a water trap. An opening time of the drain-purge valve is then determined depending on a hydrogen concentration of an anode side and a target hydrogen concentration after the draining the condensate water. Hydrogen is then purged by maintaining the drain-purge valve in a state in which it is opened for the determined opening time.

Abstract: The control unit of the fuel cell system monitors the status of power generation of the fuel cell and calculates a total amount of the fuel gas consumption, based on the amount of power generated by the fuel cell, from a point in time when the supply gas pressure reaches a standard gas pressure. Another total amount of the fuel gas consumption is calculated based on a gas pressure change that corresponds to a decrease of the gas pressure from the standard gas pressure. Comparing two total amounts of the fuel gas consumptions, the evaluation is performed as whether the on-off valve in the fuel gas flow path from each of the fuel gas tanks to the fuel cell fails to be opened.

Abstract: An apparatus and method for diagnosing a fuel cell diagnoses a state of a fuel cell by estimating a fuel-cell equivalent circuit. The apparatus for diagnosing a fuel cell includes: an impedance measurement unit configured to measure impedance of a fuel cell within a predetermined frequency range; an equivalent circuit model unit configured to derive each parameter value by estimating a predetermined fuel-cell equivalent circuit model in response to the impedance received from the impedance measurement unit; and a fuel-cell-state diagnosis unit configured to diagnose a state of the fuel cell by detecting a variation of the parameter value derived from the equivalent circuit model unit.

Abstract: One or more electrostatic discharge (ESD) control circuit are disclosed herein. In an embodiment, an ESD control circuit has first and second trigger transistors, first and second ESD transistors, and first and second feedback transistors. The ESD transistors provide ESD current paths for ESD current generated during an ESD event. The first and second trigger transistors are on during normal operation to maintain the ESD transistors in an off state. During an ESD event, the first and second transistors are turned off to enable the first and second ESD transistors to provide ESD current paths. The first and second feedback transistors turn on during an ESD event to reinforce the on state of the ESD transistors and to reinforce the off state of the trigger transistors. In this way, the ESD control circuit stably provides multiple ESD current paths to discharge ESD current.

Abstract: Provided are an apparatus and a method for managing a fuel cell vehicle system, and more particularly, an apparatus and a method for managing a fuel cell vehicle system capable of optimally maintaining a driving method based on environmental information and product information.

Abstract: A vehicle includes at least one electromotor for driving the vehicle, an actuator for controlling the supply of electric power to the electromotor, and a power system for providing electric power to the electromotor. The power system includes an energy storage, an energy meter for measuring the energy condition of the energy storage, a power generator for generating electric power, and a computer system. The energy storage supplies power to the electromotor. The power generator supplies energy to the energy storage. The computer system controls the power supplied by the power generator so that the energy storage is able to provide the electromotor with the power the electromotor needs for driving the vehicle.

Abstract: A method of controlling operation of a hybrid continuous current supply, the current supply including a fuel cell stack, a battery, and a DC/DC converter including an input and an output, the converter input being connected to the fuel cell stack output and the output being connected to a variable load in parallel with the battery, the fuel cell stack being formed of a plurality of electrochemical cells configured to produce electricity from a fuel and an oxidizing gas.

Abstract: The present invention is to provide a solid oxide fuel cell capable of improving the overall energy efficiency. The present invention is directed to a solid oxide fuel cell and comprising: a fuel cell module; a fuel supply device; a combustion chamber for burning excess fuel and heating; a heat storing material, a power demand detecting sensor; a temperature detection device, and a control device for controlling so that the fuel utilization rate is high when generated power is large, and also for changing output power at a delay to the fuel supply rate; whereby the control device comprises a stored heat amount estimating circuit, and when it is estimated that a utilizable heat amount has accumulated in the heat storing material, the fuel supply rate is reduced so that the fuel utilization rate increases vs. the same generated power.

Abstract: An impedance measuring device for outputs an alternating current to an impedance measurement object, the impedance measurement object including at least a laminated battery and computes an impedance of the laminated battery on the basis of an alternating current applied to the impedance measurement object and at least one of a positive-electrode side AC potential difference and a negative-electrode side AC potential difference. This device includes a filter configured to remove a signal with a frequency of an AC signal to the AC signal, the AC signal indicating the AC potential difference on one electrode side opposite to that of the AC potential difference used by impedance computation, and an adding unit configured to add a filtered signal to the AC signal, the filtered signal being a signal after passing through the filter, the AC signal indicating the AC potential difference used by impedance computation.

Abstract: The invention is to provide a solid oxide fuel cell system including: a fuel cell module, a fuel flow regulator unit, a first power demand detection device, a control section for controlling a fuel supply amount and setting the current value extractable from the fuel cell module, an inverter for extracting current in a range not exceeding the extractable current value, and a power state detecting sensor for detecting actual extracted current value; whereby if actual extracted current value declines, then under circumstances where power demand begins to rise in a state of extra margin in the fuel supply amount after the controller suddenly decreases the extractable current value and suddenly reduces the electrical collector, the controller increases the extractable current value at a high current rise rate of change.

Abstract: Fuel cell system mounting fuel cell vehicle including: fuel cells having platinum-containing catalyst as electrode catalyst; cell voltage meter configured to measure cell voltage of fuel cells; and controller controlling fuel cell system, wherein (a) cell voltage meter obtains first cell voltage in predefined idling state of fuel cells, (b) in response to changing operation state of fuel cell vehicle from driving state to stop state, controller changes operation state of fuel cells to idling state, and cell voltage meter obtains second cell voltage of fuel cells in idling state, (c) controller uses difference between first and second cell voltages to obtain recovery process voltage for recovering catalyst of fuel cells and recovery process time duration wherein cell voltage of fuel cells is kept at recovery process voltage, and (d) controller reduces voltage of fuel cells to recovery process voltage for recovery process time duration, preforming recovery process of catalyst.

Abstract: Fuel cell system mounting fuel cell vehicle including: fuel cells having platinum-containing catalyst as electrode catalyst; cell voltage meter configured to measure cell voltage of fuel cells; and controller controlling fuel cell system, wherein (a) cell voltage meter obtains first cell voltage in predefined idling state of fuel cells, (b) in response to changing operation state of fuel cell vehicle from driving state to stop state, controller changes operation state of fuel cells to idling state, and cell voltage meter obtains second cell voltage of fuel cells in idling state, (c) controller uses difference between first and second cell voltages to obtain recovery process voltage for recovering catalyst of fuel cells and recovery process time duration wherein cell voltage of fuel cells is kept at recovery process voltage, and (d) controller reduces voltage of fuel cells to recovery process voltage for recovery process time duration, preforming recovery process of catalyst.

Abstract: An impedance measuring device outputs an AC signal having a predetermined frequency to each of a positive electrode terminal and a negative electrode terminal of the fuel cell. The impedance measuring device includes a detection unit that detects an AC potential difference between the positive electrode terminal and a midpoint of the fuel cell, and an adjustment unit that adjusts an amplitude of the AC signal to adjust a detection signal to a predetermined value. The impedance measuring device includes an in-phase component extraction unit that multiplies the detection signal by an in-phase signal and extracts a resistance component of the detection signal, and a calculation unit that calculates a positive real axis impedance on the basis of the resistance component and the output signal.

Abstract: A system and method for limiting voltage cycling of a fuel cell stack during a stand-by mode by providing power from a battery to the stack while the stack is turned off. The method includes monitoring the voltage of each of the fuel cells in the fuel cell stack and determining an average cell voltage of the fuel cells in the fuel cell stack. The method also determines whether the average cell voltage of the fuel cells in the fuel cell stack has fallen below a predetermined voltage value and, if so, applies a voltage potential to the fuel cell stack to increase the average cell voltage above the predetermined voltage value.

Abstract: A fuel cell system includes a cathode gas supply unit, a cathode pressure detection unit, a fuel cell temperature detection unit configured to detect a temperature of the fuel cell, an internal resistance detection unit configured to detect an internal resistance of the fuel cell, a target cathode flow rate calculation unit configured to calculate a target cathode flow rate necessary for supply to the fuel cell based on an operating state of the fuel cell system, a cathode flow rate estimation unit configured to estimate a flow rate of the cathode gas according to the pressure of the cathode gas, the temperature of the fuel cell and the internal resistance of the fuel cell, and a cathode flow rate control unit configured to control the cathode gas supply unit based on the target cathode flow rate and the estimated flow rate of the cathode gas.

Abstract: A fuel cell system (100) is provided with a voltage detection device (41) that detects a cell voltage of a cell group containing one or more cells (11), a current density detection device (42) that detects a generated current density of the cell group, and a determination portion (52) that determines the presence or absence of an inflection point of a change in the cell voltage relative to the generated current density based on the detection results of the voltage detection device and the current density detection device.

Abstract: A Raman spectroscopic apparatus analyzes a substance under analysis and includes a light source that emits light of a first wavelength, an optical device that adsorbs the substance under analysis and is irradiated with the light of the first wavelength, and an optical detector that receives light radiated from the optical device. The optical device includes a first structural member that generates charge transfer resonance in response to the light of the first wavelength and a second structural member that is less than or equal to 5 nm from the first structural member and generates surface plasmon resonance in response to the light of the first wavelength. The first structural member is made of a metal or a semiconductor, and the second structural member is made of a metal different from the material of the first structural member.

Abstract: A method of detecting defects in membranes such as ion exchange membranes of electrochemical cells. The electrochemical cell includes an assembly having an anode side and a cathode side with the ion exchange membrane in between. In a configuration step a chemochromic sensor is placed above the cathode and flow isolation hardware lateral to the ion exchange membrane which prevents a flow of hydrogen (H2) between the cathode and anode side. The anode side is exposed to a first reactant fluid including hydrogen. The chemochromic sensor is examined after the exposing for a color change. A color change evidences the ion exchange membrane has at least one defect that permits H2 transmission therethrough.

Abstract: A method is generally described which includes altering the temperature of an electrical energy storage device or an electrochemical energy generation device includes configuring a controller with a control algorithm to control the actions of a fluid control system as a function of current draw from the electrical energy storage device or the electrochemical energy generation device, the electrical energy storage device or the electrochemical energy generation device configured to provide electrical current. The method also includes providing A microchannel thermal control system for the electrical energy storage device or the electrochemical energy generation device. The microchannel thermal control system is configured to cool at least portions of the electrical energy storage device or the electrochemical energy generation device.

Abstract: An apparatus and method to detect a short circuit event in a fuel cell system of a vehicle. The detection relies on three existing sensors within the fuel cell system, two current sensors and a voltage sensor. A controller executes an algorithm with a set of thresholds stored in a computer readable medium to monitor the sensors to sense if any of the threshold values are crossed. If crossed, the controller may take remedial action to stop the short circuit and/or prevent damage to the fuel cell system. A mode manager may work with the controller to determine when the operating conditions of the fuel cell system are ideal for sensing for a low voltage condition indicative of a short circuit event. A pair of integrators may be electrically coupled to an alternating current sensor to differentiate a short circuit event from a high frequency resistance current.

Abstract: A microbial fuel cell comprising: a first cathode; at least two anodes electrically connected to each other and to the cathode in a reconfigurable manner; and a processor operatively coupled to the anodes and configured to monitor a parameter of each anode to determine if a given anode has been oxygen-contaminated, and further configured to convert an oxygen-contaminated anode into a second cathode by reconfiguring the electrical connections.

Abstract: The present invention provides an apparatus for controlling hydrogen supply of a fuel cell system and a method for controlling the same. The apparatus includes a jet pump, a proportional control solenoid valve, and a controller. The jet pump is disposed at the side of an inlet of a fuel cell stack and performs supply and recirculation of hydrogen into the fuel cell stack. The proportional control solenoid valve is connected to a hydrogen supply line and fluidly communicates with a nozzle inlet of the jet pump to control the hydrogen supply to the jet pump. The controller controls an operation of the proportional control solenoid valve according to a power of the fuel cell system. Here, the controller controls the operation of the proportional control solenoid valve according to a pulse flow control method at a low power section in which a current power is lower than a predetermined reference power.

Abstract: A fuel cell system, and a method of controlling an operation of a plurality of fuel cells. The fuel cell system controls the operation of the plurality of fuel cells according to a power consumed in a load and the performance of the plurality of fuel cells, thereby increasing a power conversion efficiency of the plurality of fuel cells while preventing considerable performance degradation of the plurality of fuel cells. The fuel cell system includes: a plurality of fuel cells; a control unit controlling an operation of the plurality of fuel cells according to a power consumed in a load and the performance of the plurality of fuel cells; and a converter converting a power output by at least one of the plurality of fuel cells into a power according to the control of the control unit.

Abstract: A fuel cell stack (10) is operated with a low air utilization which is very low when the stack is providing low current density, and is operated with air utilization increasing as a function of current density above a predetermined current density.

Abstract: A fuel cell system is disclosed with a fuel cell stack having a plurality of fuel cells, the fuel cell stack including an anode supply manifold and an anode exhaust manifold, a sensor for measuring at least one of an environmental condition affecting the fuel cell stack and a characteristic of the fuel cell stack, wherein the sensor generates a sensor signal representing the measurement of the sensor; and a processor for receiving the sensor signal, analyzing the sensor signal, and controlling a flow rate of a fluid flowing into the anode supply manifold based upon the analysis of the sensor signal.

Abstract: A method a system and method for optimizing the power distribution between a fuel cell stack and a high voltage battery in a fuel cell vehicle. The method includes defining a virtual battery hydrogen power for the battery that is based on a relationship between a battery power request from the battery and an efficiency of the battery and defining a virtual stack hydrogen power for the fuel cell stack that is based on a relationship between a stack power request from the fuel cell stack and an efficiency of the fuel cell stack. The virtual battery hydrogen power and the virtual stack hydrogen power are converted into polynomial equations and added together to provide a combined power polynomial equation. The combined power polynomial equation is solved to determine a minimum of the fuel cell stack power request by setting a derivative of the virtual stack hydrogen power to zero.

Abstract: A method and system for controlling a fuel cell vehicle are provided in which a bidirectional converter monitors a state of a fuel cell vehicle in real time to improve control responsiveness in a transient state of the fuel cell vehicle. The method includes receiving, by a bidirectional converter, a command for a current limiting value in the high voltage battery from the fuel cell controller while the fuel cell vehicle is driven. In addition, the bidirectional converter is configured to determine whether the fuel cell vehicle is switched to a predetermined mode and change the current limiting value of the high voltage battery. A predetermined control is performed by the bidirectional converter based on the changed current limiting value when the fuel cell vehicle is switched to the predetermined mode.

Abstract: The present invention concerns an electrochemical system (100) including a stack of series connected electrochemical units (102). The system is controlled by a control circuit (104) and includes a plurality of differential amplifiers (114), each connected by two inputs to the terminals of an electrochemical unit, in order to supply a voltage representative of the potential difference present between the terminals of said electrochemical unit. Each representative voltage is sent to a control unit (106) arranged for converting said representative voltage into a numerical value transmitted to the control circuit. The system further includes, between each differential amplifier and the control unit, a buffer means (116) controlled by the control circuit. The buffer means is capable of saving the voltage representative of the potential difference present between the terminals of the electrochemical unit to which it is connected. The voltage is saved simultaneously by all of the buffer means.

Abstract: Disclosed herein are processes for recovering performance of fuel cells by recovering fuel cell catalyst activity and methods of testing the durability and activity performance of fuel cells. One catalyst recovery process disclosed herein for a fuel cell having a membrane electrode assembly comprises operating the fuel cell for a first recovery cycle with fuel gas supplied to an anode of the fuel cell and an oxidant supplied to a cathode of the fuel cell while drawing a current from the fuel cell at steady state throughout the first recovery cycle, the first recovery cycle having a predetermined time period. The fuel cell has reached end of life due in part to intermittent use prior to operating the fuel cell for the first recovery cycle. A life of the fuel cell improves when the first recovery cycle is complete.

Abstract: An arrangement for improved operability of a high temperature fuel cell device at higher fuel cell voltage values than nominal voltage values, each fuel cell in the fuel cell device including an anode side, a cathode side, and an electrolyte between the anode side and the cathode side, and the arrangement includes means for determining temperature information of the fuel cells and main power converter for loading fuels cells at least up to their rated power level.

Abstract: A fuel cell assembly according to an exemplary aspect of the present disclosure includes, among other things, a first fuel cell stack in series with a variable resistor and a second fuel cell stack in parallel with the first fuel cell stack and in series with a contactor. A resistance level of the variable resistor is adjusted in response to deactivating the contactor.

Abstract: It is possible to prevent excessive power generation of a fuel cell when a failure has occurred. When a start signal is input, a fuel cell system sets an open end voltage of the fuel cell as an initial value of the output voltage of the fuel cell corresponding to the output current zero of the fuel cell. When the failure is detected, the fuel cell system reads out the open end voltage of the preset initial value as the output voltage corresponding to the output current zero and controls the voltage so that the output voltage of the fuel cell coincides with the open end voltage.

Abstract: A control circuit controls power generation by a power cell in a presence of fuel and oxidant through electrical control. The control circuit may be extended to an array of power cells or array of banks of power cells to configure the cells or banks in series-row and column combinations to generate power in a selectable manner. The controller may include basic power maintenance and control of the array of power cells, and high level control modules may provide unique power generation control to cause the array to cold start, output time-varying waveforms, output multiple DC voltages from a single source of energy, regulate voltage or current, and so forth. Because the power cells may be configured in vast arrays, power cells may be connected to a group of other power cells in the array and driven with a time-varying voltage or pulse to self-clean catalyst of contaminants.

Abstract: A fuel cell system includes; a fuel cell which generates electricity by using a fuel gas and an oxidant gas as reaction gases; current control means which controls current of a fuel cell; voltage control means which controls voltage of the fuel cell; and heat value control means which calculates a heat value required by the fuel cell system and decides a target current value of the current control means and a target voltage value of the voltage control means so as to generate the calculated necessary heat amount, thereby controlling the heat value. Thus, it is possible to supply a heat required for the fuel cell system without increasing the size of the fuel cell system.

Abstract: A solid oxide fuel cell capable of maintaining performance over a long time period by appropriately changing fuel cell module operating conditions. The present invention is a solid oxide fuel cell (1), having a fuel cell module (2), a fuel supply device (38), an oxidant gas supply device (45), and a controller (110) for controlling the amount of fuel supplied from the fuel supply device; the controller is furnished with a degradation determining circuit (110a) for determining degradation in the fuel cell module and a degradation response circuit (110b) for changing fuel cell module operating conditions based on the degradation determination by the degradation determining circuit; the degradation determination stores fuel cell module operating results arising from the operating conditions changed by the degradation response circuit, and executes further degradation determination based on the stored operating results.

Abstract: A system and method for controlling an output of a dynamic fuel cell is provided. A dynamic fuel cell has a membrane wherein a dimension of the membrane is variable during operation of the dynamic fuel cell in response to a control signal from an intelligent controller. By varying the dimension of the membrane, the output voltage of the dynamic fuel cell can be altered. An intelligent controller is provided that can measure a number of outputs and input parameters of the dynamic fuel cell and approximate input parameters using the measured values to adjust the input of the dynamic fuel cell to the approximated values.

Abstract: A fuel cell system includes a fuel cell, a multiphase voltage conversion device with N-phases (N being an integer equal to or larger than two) that is connected to the fuel cell, a control signal generation portion that generates control signals to control each phase of the multiphase voltage conversion device by superimposing a control waveform for measuring impedance on a voltage indicating an output target voltage of the multiphase voltage conversion device and sequentially outputs the control signals corresponding to N phases with a predetermined phase difference to the multiphase voltage conversion device, and an impedance calculation portion that measures a current and a voltage of the fuel cell on cycles corresponding to N predetermined sampling frequencies having a phase difference equal to the predetermined phase difference and calculates an impedance of the fuel cell based on the measured current and the measured voltage.

Abstract: Provided is a fuel cell system including: a fuel cell which generates power by an electrochemical reaction between an oxidant gas supplied to an oxidant gas flow path and a fuel gas supplied to a fuel gas flow path; and a controller which adjusts an amount of the oxidant gas supplied to the fuel cell and a voltage of the fuel cell. The controller has an obstruction degree determining unit which determines a degree of obstruction of the oxidant gas flow path based on a stoichiometric ratio of the oxidant gas and the voltage of the fuel cell during a low-efficiency operation in which the stoichiometric ratio of the oxidant gas is reduced from the stoichiometric ratio of the oxidant gas during a normal operation and heat discharged from the fuel cell is increased from that during the normal operation. This improves stability of the low-efficiency operation of the fuel cell system.

Abstract: A fuel cell apparatus includes a fuel cell generating electric power, and including a fuel electrode which includes an anode catalyst, which is disposed in one side of an electrolyte membrane, which is supplied with liquid fuel, and which discharges gas generated by a chemical reaction accelerated by the anode catalyst, and an oxidizing agent electrode which includes a cathode catalyst, which is disposed in the other side of the electrolyte membrane, and which is supplied with air, and a control unit controlling a load applied to the fuel cell. The control unit increases the load in at least one of two cases, one case being when electric power generated by the fuel cell lowers below a predetermined reference value and another case being at predetermined time intervals, and stops the increase of the load after elapsing a predetermined time period from the start of the increase of the load.

Abstract: The present disclosure relates to systems and methods that may be used to predict a performance metric of a fuel cell. A system consistent with the present disclosure may include sensors in communication with the fuel cell stack, a performance metric prediction system, and a control system. The performance metric prediction system may determine a current density based on inputs provided by the sensors at a plurality of time periods, calculate a first parameter while the current density is below a lower threshold, and calculate a second parameter while the current density is above an upper threshold. The first parameter and the second parameter may be used to selectively adjust a fuel cell polarization curve over time. Based upon the polarization curve, a performance metric of the fuel cell stack may be predicted. The control system may implement a control action based upon the performance metric.

Abstract: A fuel cell system comprising a fuel cell and a motor connected to the fuel cell, and also comprising a converter connected between the fuel cell and the motor, the converter adjusting output of the fuel cell to output to the motor, and a controller that controls the fuel cell and the converter. The controller outputs, to the converter, request power or a request voltage based on an operation state of the fuel cell, and the converter selectively performs an output feedback control that performs an adjustment of supply power to be output to the motor such that the output request power is satisfied or a voltage feedback control that performs an adjustment of an output voltage to be output to the motor such that the output request voltage is satisfied.

Abstract: A fuel cell system includes: a fuel cell including a cell laminate; an estimating unit for estimating a residual water content distribution in the reactant gas flow channel in a cell plane of each of the single cells and a moisture content distribution in the electrolyte membrane in consideration of water transfer through the electrolyte membrane between the anode electrode and the cathode electrode; and an operation control unit for limiting an electric current drawn from the fuel cell when a residual water content in the reactant gas flow channel estimated by the estimating unit is equal to or above a predetermined threshold.

Abstract: A technique is described herein for monitoring the operational state of a fuel cell stack by the detection of nonlinearity in such a manner that an external test signal for frequency response is generated and applied to the fuel cell stack during operation, the resulting signal output from the fuel cell stack is measured, and the harmonic content of the measured signal is analyzed, the method including: applying a multiple frequency test signal comprising at least two sinusoidal waves as the test signal for frequency response to the fuel cell stack; and analyzing the resulting current or voltage signal output from the fuel cell stack.

Abstract: The present invention detects a failure in an FC converter. A target voltage determination section determines an output target voltage for a fuel cell. A superimposition signal generation section generates a predetermined reference signal to be superimposed onto the output target voltage. A voltage command signal generation section generates a voltage command signal by superimposing the reference signal onto the output target voltage. A frequency characteristics calculation section calculates the frequency characteristics of the reference signal component superimposed on the output voltage of the fuel cell. A failure judgment section judges that a failure occurs in the FC converter if a value of the calculated frequency characteristics is less than the lower limit threshold value of an allowable range established based on reference characteristics.

Abstract: A method including shutting down an electrochemical fuel cell stack wherein anode pressure is controlled according to a stack discharge fuel consumption estimate.

Abstract: Output voltage of a fuel cell 2 is decreased by a converter 51 to conduct an activation treatment to catalyst of the fuel cell 2, while measuring reduction current by a current sensor 2a while scanning output voltage of the fuel cell 2 over a certain range by the converter 51 as measurement of cyclic voltammetry under the condition that supply of oxidation gas to the fuel cell 2 is stopped from a compressor 31, and this measurement value is integrated by a control device 6. The control device 6 finds a charge amount of electrode catalyst of the fuel cell 2 based on this integration value, decides whether this charge amount is smaller or not than a degradation decision value, and displays this decision result on a display 55. A decision can be made precisely as to whether the electrode catalyst of the fuel cell is degraded or not.

Abstract: A fuel cell system capable of measuring AC impedance comprises: power generation stabilizing means for stabilizing power generation in a fuel cell, and impedance measuring means for measuring the AC impedance after power generation in the fuel cell has been stabilized. Since the AC impedance in a low frequency range is measured after power generation in the fuel cell is stabilized, no external disturbance occurs during measurement, and the AC impedance can be measured with a high degree of precision. Thus, a fuel cell system and a measuring method with which AC impedance can be measured with a high degree of precision can be provided.