Humidifier for fuel cell and process for warming the same

A fuel cell system comprising a humidifier for humidifying a fuel cell, comprising:

• at least one hollow fiber membrane module for migrating moisture between a supply gas, which is supplied to the fuel cell, and an exhaust gas, which is exhausted from the fuel cell to thereby humidify the supply gas;
• a supply gas inlet head and a supply gas outlet head for holding both ends of the hollow fiber membrane module therebetween,
• a connecting member for connecting the supply gas inlet head and the supply gas outlet head, and
• a warming device for warming the humidifier including a first conduit in communication with a cooling medium outlet of the fuel cell through which a cooling medium exhausted from the fuel cell is passed, wherein the first conduit is arranged relative to the supply gas outlet head to warm the supply gas exiting the humidifier by heat exchange with the heated cooling medium passing through the first conduit, and a second conduit in communication with the first conduit and arranged relative to the supply gas inlet head for warming the supply gas entering the humidifier by heat exchange with the cooling medium after warming the supply gas exiting the humidifier, the second conduit communicating with a cooling medium inlet of the fuel cell to pass the cooling medium to the fuel cell after warming the supply gas, and the warming device being unified with the connecting member.