Fuel cell system and purge method therefor

A purge method for a fuel cell system, wherein

• the fuel cell system includes:
• a fuel cell including an inlet and an outlet for purge gas;
• a first injection device and a second injection device that inject the purge gas;
• a gas-liquid separator that separates liquid water from the purge gas discharged from the outlet and causes the liquid water to flow out from an opening provided at a vertically lower side of the gas-liquid separator;
• a discharge valve that discharges the liquid water flowing out from the opening to an outside;
• an ejector including:
• an inflow port into which the purge gas flows from the gas-liquid separator;
• and
• an outflow port through which the purge gas injected from the first injection device flows out together with the purge gas flowing from the inflow port;
• a first connection path connected between the outflow port and the inlet;
• an introduction path that introduces the purge gas injected from the second injection device into the first connection path without flowing through the ejector;
• a second connection path connected between the gas-liquid separator and the outlet;
• and
• a third connection path connected between the gas-liquid separator and the inflow port, and extending vertically upward from the gas-liquid separator, and
• the purge method comprises:
• purging the ejector, the fuel cell, and the second connection path by performing injection of the first injection device;
• purging the third connection path by stopping the injection of the first injection device and by performing injection of the second injection device;
• and
• discharging the liquid water in the gas-liquid separator by opening the discharge valve.