Patent ID: 8822095

Claim:
A fuel cell system comprising: a fuel cell stack comprising a plurality of fuel cells sandwiched between two end plates; a fuel supply system to supply a stream of fuel gas to the fuel cell stack; an oxidizer supply system to supply a stream of oxidizer gas to the fuel cell stack; a closed loop coolant circulation system to drive a cooling liquid through the fuel cell stack so that the cooling liquid enters the fuel cell stack, absorbs heat from the fuel cells, and exits the fuel cell stack, the coolant circulation system comprising a circulation pump to drive the cooling liquid, a heat exchanger to remove heat from the cooling liquid and for at least partially transferring the heat to the stream of fuel gas and/or the stream of oxidizer gas; wherein the heat exchanger comprises a tube made from a heat-conducting material and inserted into a bore in one of the end plates, the tube and the bore defining at least a first fluid channel inside the tube and a second fluid channel in a space existing between the tube and sides of the bore in the end plate, one of the first and second fluid channels being for the cooling liquid, and the other fluid channel being for the fuel or the oxidizer gas.