A fuel cell vehicle capable of generating electric power in an optimum wet state is provided. A fuel cell vehicle including a fuel cell, a radiator configured to cool a coolant which has been warmed by cooling the fuel cell and send it back to the fuel cell, a grille shutter configured to adjust a flow rate of air taken into the radiator from an air intake, a sensor configured to measure an impedance of the fuel cell, and a control unit configured to control the grille shutter to open and close. The control unit controls the grille shutter to open when a measured value of the impedance becomes greater than or equal to a predetermined threshold.

A fuel cell system includes a fuel cell stack including a plurality of single cells stacked, a dry-wet detection unit that detects a dry-wet state of the fuel cell stack, and an operation control unit that controls operation of the fuel cell stack. When an operating condition under which the fuel cell stack is at a high temperature and at a high load is established, the dry-wet detection unit determines whether the fuel cell stack is in a deviation state of deviating from an ideal dry-wet state based on a physical quantity having a higher correlation with drying and wetting of the fuel cell stack than the temperature of the fuel cell stack. When the deviation state is detected, the operation control unit performs a reset operation for recovering the dry-wet state.

A device for detecting a current leakage and a current leakage detection system including the same are provided. The device for detecting a current leakage includes a magnetic core having an internal space and both ends the core are separated from each other. An electric wiring extends to pass through the internal space of the magnetic core, and is connected between a power source and an electric load to supply power from the power source to the electric load. A hall sensor senses a magnetic field induced in the magnetic core.

A state estimation device for a fuel cell for generating power upon receiving the supply of anode gas and cathode gas, comprising: an internal impedance measurement unit configured to measure an internal impedance of the fuel cell on the basis of an alternating-current signal of a predetermined frequency output from the fuel cell; a state quantity preliminary estimation value calculation unit configured to calculate a first preliminary estimation value for a state quantity of an electrode obtained from a real component of a measurement value of the internal impedance and a second preliminary estimation value for the state quantity of the electrode obtained from an imaginary component of the measurement value of the internal impedance; and a state quantity final estimation value determination unit configured to determine a final estimation value of the state quantity of the electrode on the basis of the calculated first and second preliminary estimation values.

An electrochemical fuel cell assembly comprises a fuel cell stack having a fuel delivery inlet and a fuel delivery outlet. The fuel cell stack further includes a number of fuel cells each having a membrane-electrode assembly and a fluid flow path coupled between the fuel delivery inlet and the fuel delivery outlet for delivery of fuel to the membrane electrode assembly. A fuel delivery conduit is coupled to the fuel delivery inlet for 10 delivery of fluid fuel to the stack. A bleed conduit is coupled to the fuel delivery outlet for venting fluid out of the stack. A variable orifice flow control device coupled to the bleed conduit configured to dynamically vary an amount of fluid from the fuel delivery outlet passing into the bleed conduit as a function of one or more of the control parameters: (i) measured fuel concentration; (ii) measured humidity; (iii) cell voltages of fuel cells in the 15 stack; (iv) impedance of fuel cells in the stack; (v) resistance of fuel cells in the stack. The variable orifice flow control device may be coupled to a recirculation conduit and may be configured to dynamically vary a proportion of fluid from the fuel delivery outlet passing into the bleed conduit as a function of the control parameters.

A fuel cell system includes: a fuel cell stack; a first cooling medium circuit through which a cooling medium for cooling the fuel cell stack flows; an ion exchanger that removes ions in the cooling medium; a second cooling medium circuit in which the average ion concentration of the cooling medium is lower than that of the cooling medium in the first cooling medium circuit; a switching valve that switches between a flow state and a low flow state; a pump configured to cause the cooling medium in the second cooling medium circuit to flow into the first cooling medium circuit; and a control unit that, when a stop period of the fuel cell system is longer than a reference period, drives the pump with the switching valve switched to the flow state after the instruction to start the fuel cell system is input.

A measurement error of a water content depends on a phase difference of a low frequency. The low frequency is a lower one of two frequencies in an alternating current signal used for calculating an impedance of a cell. The phase difference is a difference between a phase of a current value of an alternating current signal applied to a fuel cell stack and a phase of a voltage value of output current. The calculated value of the water content is not used when the phase difference of the low frequency indicates that the measurement error may largely fluctuate.

A power supply device includes a power supply, a conversion unit performing voltage conversion on electric power to be supplied from the power supply, and a control unit generating a first control signal for inputting or outputting a target voltage or a target current to and from the conversion unit by a feedback loop, and controlling the conversion unit based on the first control signal and a second control signal for detecting a state of the power supply, generated outside the feedback loop. The control unit sets a specific parameter of the second control signal based on a feedforward term based on the output of the power supply and a feedback term in which the specific parameter included in at least one of electric power output from the power supply and input into the conversion unit and electric power output from the conversion unit, is a feedback component.

An apparatus and method for controlling operation of a fuel cell system is provided. The method includes measuring a stack current and a stack insulation resistance. The measured stack current is compared with a predetermined current reference value and the measured stack insulation resistance is compared with a predetermined first insulation reference value. An air supply amount to a fuel cell stack is increased during a predetermined time when the measured stack current is less than the predetermined current reference value and the measured stack insulation resistance is less than or equal to the predetermined first insulation reference value.

When reduction of insulation resistance is detected, an FC positive side relay is opened, and a switching element is turned OFF. When the insulation resistance has returned to a normal value as a result of the relay opening and the switching element turning OFF, it is identified that the power leakage is occurring in the area between the positive side relay and the diode.