Patent ID: 8691455

Claim:
A method of operating a fuel cell system to supply power to a load, the fuel cell system including a fuel cell stack including unit cells, and switches to selectively complete short circuits connected to the unit cells, the method comprising: performing a cycle to short circuit each of the unit cells when the load is not connected to the fuel cell stack, the cycle comprising selectively closing each of the switches for a first time (t), such that each of the switches selectively completes a short circuit of less than all of the unit cells, and opening each of the switches for a second time (T), at least two of the switches being closed at different times and the closing and opening of each of the switches being performed in a predetermined sequence; and repeating the performing of the cycle, such that the predetermined sequence is repeated in each cycle, until a residual fuel in the fuel cell stack is consumed, wherein the first time (t) is shorter than the second time (T), and the repeating of the performing includes adjusting the first time (t) and the second time (T) according to a temperature of the fuel cell stack.