Method and apparatus for internal hydration of a fuel cell system

A fuel cell system having internal pushback of water, with a compact, thermally integrated enthalpy exchanger enabling effective hydration control in a small fuel cell system is provided. The enthalpy exchanger provides for the moisture in the fuel cell effluent to be used to humidify the incoming air stream to allow the fuel cell to be operated at higher temperatures while avoiding dry out. The enthalpy exchanger includes a moisture permeable membrane which collects moisture from the exhaust flow and makes this moisture available to an incoming air stream, thus humidifying the incoming air stream. In addition, the waste heat from the fuel cell reactions is transferred to the incoming air stream. The exhaust stream from the anode can also be used to provide additional moisture and heat to the enthalpy exchanger to be added to the incoming air stream. A water separator is also provided in one embodiment.