Abstract: A method of detecting degradation of a membrane electrode assembly in a fuel cell system is provided. In the method, it is possible to detect degradation (cross leakage) of a fuel cell. In the state where variation of a load is suppressed, variation of the gas pressure where a predetermined amount of the fuel gas is supplied from a fuel tank to a fuel cell is measured by a pressure sensor provided in a fuel gas circulation channel extending from the fuel gas outlet to the fuel gas inlet.

Abstract: A method of detecting degradation of a membrane electrode assembly of a fuel cell is provided. In the method, it is possible to detect degradation (cross leakage) of the fuel cell. In the measurement step, the pressure drop value of the pressure of the fuel gas which decreases in the power generation state after discharging of the predetermined amount of the fuel gas, in each predetermined period of time is measured a plurality of times. Thereafter, in the determination step, it is determined that the membrane electrode assembly has been degraded in the case where the minimum pressure drop value, among a plurality of pressure measurement values, exceeds a threshold value.

Abstract: A method of detecting degradation of a membrane electrode assembly of a fuel cell is provided. In the method, it is possible to detect degradation (cross leakage) of the fuel cell. In the measurement step, the pressure drop value of the pressure of the fuel gas which decreases in the power generation state after discharging of the predetermined amount of the fuel gas, in each predetermined period of time is measured a plurality of times. Thereafter, in the determination step, it is determined that the membrane electrode assembly has been degraded in the case where the minimum pressure drop value, among a plurality of pressure measurement values, exceeds a threshold value.

Abstract: A method of detecting degradation of a membrane electrode assembly in a fuel cell system is provided. In the method, it is possible to detect degradation (cross leakage) of a fuel cell. In the state where variation of a load is suppressed, variation of the gas pressure where a predetermined amount of the fuel gas is supplied from a fuel tank to a fuel cell is measured by a pressure sensor provided in a fuel gas circulation channel extending from the fuel gas outlet to the fuel gas inlet.

Abstract: A method for controlling a fuel cell system including a fuel cell, includes generating electric current via an electrochemical reaction between a fuel gas and an oxidant gas by the fuel cell including a solid polymer electrolyte membrane. An impedance of the fuel cell is detected. It is determined whether the impedance reaches a threshold impedance. The electric current generated by the fuel cell is increased when the impedance is determined to reach the threshold impedance.

Abstract: A method for controlling a fuel cell system including a fuel cell, includes measuring an impedance of the fuel cell that includes a solid polymer electrolyte membrane to generate electric power via an electrochemical reaction between a fuel gas and an oxidant gas. An output electric current output from the fuel cell is increased to a threshold electric current value when the impedance is equal to or higher than a threshold impedance value and a target electric current value is larger than the threshold electric current value. The output electric current is maintained at the threshold electric current value. The output electric current is increased from the threshold electric current value to the target electric current value.

Abstract: 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.

Abstract: A method for controlling a fuel cell system including a fuel cell which includes an anode electrode and a cathode electrode sandwiching a solid polymer electrolyte membrane therebetween, includes driving a pump to supply an oxidant gas to the cathode electrode. The pump has a minimum supply amount of the oxidant gas. A fuel gas is supplied to the anode electrode to generate electric power via an electrochemical reaction between the fuel gas and the oxidant gas. It is determined whether a target amount of the oxidant gas to be supplied to the cathode electrode is lower than the minimum supply amount. An opening degree of a pressure adjusting valve is adjusted to adjust an amount of the oxidant gas supplied to the cathode electrode to be the target amount when the target amount is determined to be lower than the minimum supply amount.

Abstract: A method for controlling a fuel cell system including a fuel cell which includes an anode electrode and a cathode electrode sandwiching a solid polymer electrolyte membrane therebetween, includes driving a pump to supply an oxidant gas to the cathode electrode. The pump has a minimum supply amount of the oxidant gas. A fuel gas is supplied to the anode electrode to generate electric power via an electrochemical reaction between the fuel gas and the oxidant gas. It is determined whether a target amount of the oxidant gas to be supplied to the cathode electrode is lower than the minimum supply amount. An opening degree of a pressure adjusting valve is adjusted to adjust an amount of the oxidant gas supplied to the cathode electrode to be the target amount when the target amount is determined to be lower than the minimum supply amount.

Abstract: A method for controlling a fuel cell system including a fuel cell, includes generating electric current via an electrochemical reaction between a fuel gas and an oxidant gas by the fuel cell including a solid polymer electrolyte membrane. An impedance of the fuel cell is detected. It is determined whether the impedance reaches a threshold impedance. The electric current generated by the fuel cell is increased when the impedance is determined to reach the threshold impedance.

Abstract: A method for controlling a fuel cell system including a fuel cell, includes measuring an impedance of the fuel cell that includes a solid polymer electrolyte membrane to generate electric power via an electrochemical reaction between a fuel gas and an oxidant gas. An output electric current output from the fuel cell is increased to a threshold electric current value when the impedance is equal to or higher than a threshold impedance value and a target electric current value is larger than the threshold electric current value. The output electric current is maintained at the threshold electric current value. The output electric current is increased from the threshold electric current value to the target electric current value.

Abstract: 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.