Fuel cell system and control method thereof

A control method of a fuel cell system including a fuel cell that generates power when an anode gas and a cathode gas are supplied, the control method comprising:

• detecting an atmospheric pressure;
• detecting an output current of the fuel cell;
• estimating a degree of humidity inside the fuel cell;
• setting a current threshold for the output current to be a smaller value as the degree of humidity decreases;
• counting, as a number of high load cycles, a number of times a current detection value of the output current becomes equal to or more than the current threshold;
• and
• executing an increase rate limitation process of limiting an increase rate of the output current to a predetermined increase rate upper-limit value or less when the number of high load cycles becomes equal to or more than a set number of times set to 1 or more while the atmospheric pressure is less than a predetermined pressure.

A fuel cell system including a fuel cell that generates power when an anode gas and a cathode gas are supplied, the fuel cell system comprising:

• a current detector configured to detect an output current of the fuel cell;
• a degree-of-humidity estimator configured to estimate a degree of humidity inside the fuel cell;
• and
• an output controller configured to control output of the fuel cell,
• the output controller being configured to execute:
• a process of setting a current threshold for the output current to be a smaller value as the degree of humidity decreases;
• a process of counting, as a number of high load cycles, a number of times a current detection value by the current detector becomes equal to or more than the current threshold;
• and
• an increase rate limitation process of limiting an increase rate of the output current to a predetermined increase rate upper-limit value or less when the number of high load cycles becomes equal to or more than a set number of times set to 1 or more while the degree of humidity is less than a predetermined dryness determination threshold.