Fuel battery system

A fuel battery system comprising:

• a fuel battery which receives supply of a reactant gas to generate a power;
• an estimation device which estimates output properties of the fuel battery;
• a battery into which the power generated by the fuel battery is charged;
• auxiliary machines which consume the power generated by the fuel battery;
• a high potential avoidance voltage setting device which sets a high potential avoidance target voltage value to a small value, as the charge amount of the battery is small or as the power consumption of the auxiliary machines is large;
• a target power calculation device which converts the high potential avoidance target voltage value into a target power value on the basis of the output properties and which limits the target power value within a range between a predetermined upper limit value and a predetermined lower limit value;
• a control device which controls the operation of the fuel battery on the basis of the target power value while limiting the output voltage of the fuel battery to a value which is not larger than the high potential avoidance target voltage;
• and
• a voltage control device which controls the output voltage of the fuel battery,
• wherein the upper limit value and the lower limit value are set on the basis of the upper limit value and lower limit value of a passing power which passes through the voltage control device.