Control method for fuel cell system and fuel cell system

A fuel cell system configured to execute an idle stop operation to selectively stop power generation of a fuel cell according to a required output of a load and intermittently supply cathode gas from a cathode gas supplying device to the fuel cell during an operation stop, comprising:

• a wet/dry state detection unit configured to detect a wet/dry state of the fuel cell;
• an output voltage upper/lower limit value setting unit configured to set an upper limit value and a lower limit value of an output voltage of the fuel cell during the idle stop operation;
• a wet/dry range setting unit configured to set a wet/dry range for the wet/dry state of the fuel cell during the idle stop operation is appropriate;
• a wet/dry range determination unit configured to determine whether or not the wet/dry state of the fuel cell detected by the wet/dry state detection unit is within the wet/dry range set by the wet/dry range setting unit;
• an output voltage resetting unit configured to reset at least one of the upper limit value or the lower limit value of the output voltage of the fuel cell if the detected wet/dry state of the fuel cell is determined to be outside the set wet/dry range by the wet/dry range determination unit;
• and
• a control unit configured to intermittently supply the cathode gas from the cathode gas supplying device with the output voltage of the fuel cell set at a value between the upper limit value and the lower limit value of the output voltage after the resetting if the output voltage resetting unit resets the output voltage of the fuel cell.

A fuel cell system configured to execute an idle stop operation to selectively stop power generation of a fuel cell according to a required output of a load and intermittently supply cathode gas from a cathode gas supply to the fuel cell during an operation stop, comprising:

• a wet/dry state detector configured to detect a wet/dry state of the fuel cell;
• and
• a controller programmed to:
• set an upper limit value and a lower limit value of an output voltage of the fuel cell during the idle stop operation;
• set a wet/dry range for the wet/dry state of the fuel cell during the idle stop operation;
• determine whether or not the wet/dry state of the fuel cell detected by the wet/dry state detector is within the wet/dry range;
• reset at least one of the upper limit value or the lower limit value of the output voltage of the fuel cell if the detected wet/dry state of the fuel cell is determined to be outside the wet/dry range;
• and
• intermittently supply the cathode gas from the cathode gas supply with the output voltage of the fuel cell set at a value between the upper limit value and the lower limit value of the output voltage after the resetting if the output voltage of the fuel cell is reset.