An online impedance spectrum measuring device and method for a vehicle-mounted hydrogen fuel cell includes: a controllable alternating current source, configured to apply a sinusoidal alternating signal; a cell voltage signal preceding-stage measuring circuit, configured to select to communicate with one monocell via a voltage signal gating circuit; a current sensor and a cell current signal preceding-stage measuring circuit connected with the current sensor; and a signal conditioning and amplifying circuit, a multi-channel simultaneous sampling analog-digital conversion circuit, a digital signal processor and an upper computer, which are connected in sequence, wherein the signal conditioning and amplifying circuit is connected to the cell voltage signal preceding-stage measuring circuit and the cell current signal preceding-stage measuring circuit, separately; and the upper computer is connected with the controllable alternating source and the voltage signal gating circuit.

When a time point of occurrence of a stop state of a fuel cell system is predicted during traveling, a drying state control that causes a fuel cell stack to transition to a dry state is started a predetermined time (a required drying time) before the predicted time point of occurrence of the stop state.

To provide a fuel cell system configured to appropriately measure the AC impedance of a fuel cell. A fuel cell system wherein a controller controls ON and OFF of switches of n phases; wherein the controller monitors current values of coils; the controller operates the switches of the n phases at different phases; wherein the controller operates duty ratios of the switches of the n phases with periodically increasing and decreasing them, and the controller measures an AC impedance of a fuel cell from a current waveform of and a voltage waveform of the fuel cell; and wherein, when the controller determines that a predetermined condition 1 is met, the controller makes amplitudes which increase and decrease the duty ratios large compared to other operating conditions.

A fuel cell includes sensors. Each sensor includes: a sensor portion provided on at least one of separators, a frame member, and an electrolyte membrane; and a wiring portion connected to the sensor portion and extending to an outer peripheral portion of one of the separators or an outer peripheral portion of a membrane electrode assembly. The sensor further includes a base insulating film covering a sensor arrangement region; wiring patterns laminated on the base insulating film; and a covering insulating film covering the wiring patterns and portions of the base insulating film not covered with the wiring patterns.

A state detection device for a fuel cell for generating power upon receiving a supply of anode gas and cathode gas, including an impedance acquisition unit configured to acquire a high frequency impedance based on a frequency selected from a high frequency band and a low frequency impedance based on a frequency selected from a low frequency band, the high frequency band including a frequency band which shows responsiveness at least to a state quantity of an anode electrode, the low frequency band including a frequency band which shows responsiveness at least to a state quantity of a cathode electrode, and an internal state quantity estimation unit configured to estimate each of the state quantity of the anode electrode and the state quantity of the cathode electrode by combining the acquired high frequency impedance and low frequency impedance, the state quantity of the anode electrode and the state quantity of the cathode electrode serving as internal states of the fuel cell.

Accelerated testing protocols that can be utilized for determining and projecting the durability of SOFC cathodes are described. The accelerated testing protocols can be carried out under simulated operation conditions so as to provide in a matter of a few hundred hours data that can correlate to the condition of the cathode following operation of the cell over the course of a typical operation life span of several thousand hours. A testing protocol can include cycling a SOFC from OCV to operating potential at a predetermined current density. Each cycle can be relatively short, for instance less than one minute.

A system for measuring a moisture content of an ion-exchange membrane in a fuel-cell stack is provided. The fuel-cell stack includes N electrochemical cells separated by bipolar plates, with N being a natural integer. The system includes a current generator, a voltage measurement device, and an impedance measurement device. The current generator enables a current to be applied to the fuel-cell stack. The voltage measurement device measures voltages of the cells of the fuel-cell stack. The impedance measurement device determines an impedance of an ion-exchange membrane according to a voltage ripple measured by the voltage measurement device across terminals of a corresponding one of the cells of the fuel-cell stack when the current is applied by the current generator. The impedance measurement device is installed in the voltage measurement device.

An object is to provide a technique that a current state of a fuel cell may be detected more accurately. A fuel cell system includes a controller, a fuel cell, and an impedance measurer that may measure an impedance of the fuel cell. The controller obtains a first impedance value that expresses the impedance of the fuel cell in a predetermined state, acquires a second impedance value that expresses the impedance of the fuel cell that is measured by the impedance measurer during operation control of the fuel cell, and performs operation control of the fuel cell using the first impedance value and the second impedance value.

Methods and circuits for a device for interrupting concentration-related polarisation phenomenon and for self-cleaning of electromembrane processes by application of asymmetric inverse-polarity pulses with high intensity and variable frequency are described. The device, a bipolar switch, is based on the use of solid-state electronics to carry out polarity inversion in a range of frequencies, intensities and pulse widths to prevent or reduce formation of precipitates on the surfaces of the membranes. The inversion protocol, with a frequency that varies as a function of the appearance of dirt on the membranes, as measured by the decrease in voltage or electrical resistance of the membrane cell during electromembrane processes, is also provided. This device and configuration provides application of modulated and stable high-intensity pulses using a second power source. Electromembrane processes can be updated by replacing electrodes, suitable for polarity inversion, and adding a second power source and the bipolar switch described.

A method of determining hydrogen deficiency of a fuel cell having a plurality of cell groups includes a reference value storage step of storing, as a reference value, a value of impedance in a state where hydrogen-off gas is discharged from the fuel cell and hydrogen gas and oxidant gas are supplied, a measured value calculation step of calculating a measured value of impedance based on a voltage of the cell groups and a current of the fuel cell, a corrected value calculation step of calculating a corrected value of impedance by correcting the measured value based on the reference value, and a determination step of determining that hydrogen deficiency occurs in a case where the corrected value exceeds a predetermined threshold.