Patent ID: 7087328

Claim:
A fuel cell system, which has a fuel cell that generates electrical power by the electrochemical reaction between a fuel gas supplied to an anode and an oxidant gas supplied to a cathode, and a humidifying apparatus that humidifies the gases with water permeable membranes, comprising: a first humidifier, which is provided in said humidifying apparatus; and non-porous water permeable membranes having a pore size less than 10 nanometers, which are provided in said first humidifier to humidify said fuel gas supplied to said anode by means of the moisture contained in off-gas discharged from said fuel cell, wherein said humidifying apparatus has a second humidifier, and said second humidifier has porous water permeable membranes having a pore size of 10 nanometers or greater, which humidify said oxidant gas supplied to said cathode by means of said off-gas.