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 method for controlling a fuel cell system includes supplying an oxidant gas, via an oxidant gas supply channel, to a cathode electrode of a fuel cell. The oxidant gas is moistened to be supplied to the cathode electrode with a humidifier. An opening degree of a bypass channel valve is decreased via a feedforward control to a first opening degree when an impedance has reached a lower limit value. The opening degree of the bypass channel valve is increased via the feedforward control to a second opening degree when the impedance has reached an upper limit value. The first opening degree is smaller than the second opening degree.

A fuel cell control method includes detecting a state value indicating a state in a fuel cell during an operation of the fuel cell. The fuel cell includes a membrane electrode assembly and a separator stacked on the membrane electrode assembly. The membrane electrode assembly includes a solid polymer electrolyte membrane sandwiched between an anode electrode and a cathode electrode. It is determined whether a liquid connects the solid polymer electrolyte membrane and the separator based on the state value detected. The fuel cell is dried in a case where it is determined that the liquid connects the solid polymer electrolyte membrane and the separator.

A power supply system includes a power supply, a conversion module, and a processor. The conversion module includes conversion units to convert, based on a first control signal, voltage of electric power supplied from the power supply. The conversion units are electrically connected in parallel. The processor is configured to change a number of operating conversion unit among the conversion units. The processor is configured to generate the first control signal to generate a DC component in the electric power output from the power supply. The processor is configured to generate a second control signal to detect a state of the power supply. An AC component is generated according to the second control signal in the electric power output from the power supply such that the AC component has an amplitude based on the number of operating conversion unit.

A power supply system includes a power supply, a converter, and a processor. The converter converts voltage of the electric power supplied from the power supply. The processor is configured to generate a first control signal to control the converter to output a target voltage or a target current via a feedback control based on the first control signal. The processor is configured to generate a second control signal to detect a state of the power supply. The processor is configured to combine the first control signal and the second control signal to control the converter.

A state determination 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; and an anode reaction resistance estimation/calculation unit configured to calculate an estimation value of a reaction resistance of an anode electrode of the fuel cell on the basis of a measurement value of the internal impedance, wherein: the predetermined frequency is selected such that a difference between the estimation value of the reaction resistance of the anode electrode during hydrogen starvation and the estimation value of the reaction resistance of the anode electrode during oxygen starvation is not smaller than a predetermined value.

Artifacts from the presence of a reference electrode in a thin-film cell configuration can be minimized or eliminated by providing the surface of a reference electrode with a specified surface resistivity. Theoretical considerations are set forth that show that for a given wire size, there is a theoretical surface resistance (or resistivity) that negates all artifacts from the presence of the reference wire. The theory and the experimental results hold for a electrochemical cell in a thin-film configuration.

A redox flow battery system including a cell and a monitor cell to which a same electrolyte solution is supplied; a current measuring unit that measures a current that is input to and output from the cell; a voltage measuring unit that measures an open circuit voltage of the monitor cell; and a computing unit. The computing unit includes a first processing unit, a second processing unit, and a third processing unit. The first processing unit computes an integral value obtained by integrating a current value measured by the current measuring unit, for an amount of time corresponding to a predetermined time constant. The second processing unit computes a corrected voltage value based on a measured voltage value measured by the voltage measuring unit and the integral value. And the third processing unit calculates a first state-of-charge value of the electrolyte solution from the corrected voltage value.

An output performance diagnosis apparatus for a fuel cell acquires, in a case where determination is made that a representative value of impedance of the fuel cell acquired during a trip of a vehicle traveling with a fuel cell as a power source is equal to or less than an impedance threshold, during the trip in which the impedance is acquired, a current-voltage characteristic of the fuel cell based on a change of an output voltage of the fuel cell after a period in which the output voltage of the fuel cell is maintained in a range equal to or higher than a lower limit voltage and equal to or lower than a voltage threshold higher than the lower limit voltage over a predetermined period or more, and calculates maximum output electric power of the fuel cell based on the acquired current-voltage characteristic.

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.