METHOD AND APARATUS FOR CONTROLLING TEMPERATURE OF COOLANT IN FUEL CELL SYSTEM

A fuel cell system includes a fuel cell stack, a first cooling line configured to circulate a first coolant that passes via the fuel cell stack, a first radiator disposed on the first cooling line, a valve configured to switch a flow path of the first coolant to the fuel cell stack or the first radiator, and a controller connected to the valve and configured to set a target temperature at an inlet of the fuel cell stack and a correction coefficient for controlling an opening degree of the valve, measure a first coolant temperature at an outlet of the fuel cell stack and a second coolant temperature at an outlet of the first radiator, calculate the opening degree of the valve based on the first coolant temperature, the second coolant temperature, the target temperature, and the correction coefficient, and correct the correction coefficient based on comparison of a third coolant temperature at the inlet of the fuel cell stack and the target temperature, in response to the opening degree being within a first range.