FUEL CELL SYSTEM AND METHOD OF REPLACING STACK MODULE OF FUEL CELL SYSTEM

A fuel cell system for enabling maintenance of a stack module without stopping operation thereof, and a method of replacing a stack module of the fuel cell system are provided. The fuel cell system includes a plurality of stack modules that are connected in parallel to a hydrogen line and an air line. Two or more of the stack modules are connected to form a group, and an inverter is connected to the group of the stack modules and is capable of being turned on and off.