Fuel cell system

A fuel cell system comprising:

• a fuel cell;
• a reformer operative to reform an electric power generation raw material to generate a hydrogen-containing gas and supply the hydrogen-containing gas to the fuel cell;
• an electric power generation raw material supply unit operative to supply the electric power generation raw material to the reformer;
• a reforming water supply unit operative to supply water to the reformer, the water being utilized in a reforming reaction in the reformer;
• an evaporator operative to evaporate the water supplied from the reforming water supply unit to the reformer;
• a heater operative to heat the evaporator;
• an oxidizing gas supply unit operative to supply an oxidizing gas to the fuel cell;
• a combustible gas channel through which the electric power generation raw material or the hydrogen-containing gas flows as a combustible gas and which is a channel extending from the electric power generation raw material supply unit to the fuel cell;
• an oxidizing gas channel through which the oxidizing gas flows and which is a channel extending from the oxidizing gas supply unit to the fuel cell;
• and
• a temperature detecting portion operative to detect at least one of temperatures of the evaporator, the reformer, and the fuel cell, the temperatures changing in conjunction with one another;
• and
• a controller, wherein
• in an operation stop process of the fuel cell, the controller causes the electric power generation raw material supply unit and the reforming water supply unit to supply the electric power generation raw material and the water to the combustible gas channel and causes the oxidizing gas supply unit to supply the oxidizing gas to the oxidizing gas channel, and when the controller determines based on a detection result of the temperature detecting portion that an operating temperature of the evaporator is a lower limit or less, the controller causes the heater to heat the evaporator.