Fuel cell system

A fuel cell system comprising:

• a fuel cell having an anode to which fuel gas is supplied, and a cathode to which oxidant gas is supplied;
• a first oxidant gas flowpath through which the oxidant gas is supplied to the fuel cell;
• a second oxidant gas flowpath through which the oxidant gas is discharged from the fuel cell;
• a first shut-off valve, being normally closed, disposed upstream from the fuel cell and connected to the fuel cell through the first oxidant gas flowpath, the first shut-off valve having a first valve body having a first engagement block connected via a first rod and disposed outside the first shut-off valve;
• a second shut-off valve, being normally-closed, disposed downstream from the fuel cell and connected to the fuel cell through the second oxidant gas flowpath, the second shut-off valve having a second valve body having a second engagement block connected via a second rod and disposed outside the second shut-off valve;
• a first opening/closing unit for opening and closing the first shut-off valve;
• a second opening/closing unit for opening and closing the second shut-off valve;
• a cathode control unit for sealing the cathode by closing the first shut-off valve and the second shut-off valve by using the first opening/closing unit and the second opening/closing unit after stopping electro-chemical reaction in the fuel cell and for releasing the sealed cathode by opening the first shut-off valve and the second shut-off valve by using the first opening/closing unit and the second opening/closing unit after starting the electro-chemical reaction in the fuel cell;
• a first valve lock unit having a first lock member and locking the first shut-off valve in open state by engaging the first lock member with the first engagement block of the first shut-off valve;
• and
• a second valve lock unit having a second lock member and locking the second shut-off valve in open state by engaging the second lock member with the second engagement block of the second shut-off valve.