FUEL CELL SYSTEM AND METHOD OF DETERMINING FUEL GAS QUALITY

The fuel cell system comprises a fuel gas tank, a fuel cell configured to generate electricity with oxidizing gas and fuel gas supplied from the fuel gas tank, a current sensor configured to detect output current from the fuel cell, a voltage sensor configured to detect output voltage from the fuel cell, and a controller. The controller is configured to determine that fuel gas quality does not meet predetermined standard quality when the controller determines output from the fuel cell has decreased using current values detected by the current sensor and voltage values detected by the voltage sensor after filling operation of the fuel gas into the fuel gas tank.