Patent ID: 8247119

Claim:
A fuel cell system comprising: a fuel cell stack formed by stacking a plurality of power generation cells; and a humidifier for humidifying at least one reactant gas supplied to said fuel cell stack using humidified fluid, wherein an end plate of said fuel cell stack and a casing of the humidifier are joined to each other using a knock pin, wherein an opening for a fluid pipe provided for said fuel cell stack is substantially aligned with an opening for a fluid pipe provided for said humidifier, the fluid pipe provided for the fuel cell stack and the fluid pipe provided for said humidifier not being in direct contact with each other, the openings of the fluid pipes connected by a separate intermediate pipe, wherein ends of the respective fluid pipes for the humidifier and the fuel cell stack include pipe connectors between which the intermediate pipe is located, the pipe connector for the fluid pipe provided for the fuel cell stack protruding from the end plate of the fuel cell stack, and wherein spaces are formed between an outer circumference formed by an exterior surface of said intermediate pipe and an inner circumference formed by an interior surface of the pipe connector of said fluid pipe for the fuel cell stack and between the outer circumference formed by the exterior surface of said intermediate pipe and an inner circumference formed by an interior surface of the pipe connector of said fluid pipe for the humidifier, O-rings being provided in said spaces that are the only point of contact between the intermediate pipe and the fluid pipes.