Patent ID: 8883359

Claim:
A method of driving a fuel cell system to discharge water in the reformer, wherein the fuel cell system comprises a reformer configured to supply reforming gas to a fuel cell stack and a water transferring pump comprising pressing members and a pump pipe having elasticity and in fluid communication with a water transferring pipe configured to supply water to the reformer, the method comprising: supplying water to the reformer by pressing the pump pipe to the pressing members to move the pressing members in a first direction; stopping power generation comprising stopping a supply of fuel and oxidant to the reformer; and discharging water in the reformer by moving the pressing members in a second direction opposite to the first direction while pressing the pump pipe with the pressing members, wherein the water transferring pump further comprises a rotating body, and a motor configured to rotate the rotating body, wherein the pressing members are installed to an edge of the rotating body, and wherein each of the pressing members is configured to rotate at the edge of the rotating body and to revolve around a periphery of the rotating body while the motor rotates the rotating body, wherein the pump pipe is installed to contact the pressing members and has elasticity to be contracted by the pressing members, wherein supplying water to the reformer comprises moving the pressing members while pressing the pump pipe in a rotatable direction of the rotating body, and wherein the rotating body contacts the pump pipe.