Fuel cell system having a valve controlling the flow of water to a reformer based on fuel tank pressure

A fuel cell system comprising:

• a fuel cell stack;
• a reformer to generate a reformed gas through a reforming reaction between a gaseous fuel and water and to supply the reformed gas to the fuel cell stack;
• a fuel tank to compress the gaseous fuel, store the compressed fuel in at least a partially liquid phase, and to supply the gaseous fuel to the reformer;
• a water tank connected to the fuel tank and the reformer to store water and to supply the water to the reformer by an internal air pressure of the fuel tank;
• a first valve installed in a connection line connecting the water tank to the fuel tank to selectively open or close the connection line according to an electrical on/off pulse signal, and
• a second valve installed in a connection line directly connecting the reformer to the water tank to selectively open or close the connection line and return water to the water tank in response to the absence or reduction in air pressure from the fuel tank.