Patent ID: 8877404

Claim:
A fuel cell, comprising: an electrolyte membrane; first and second catalyst layers formed on respective faces of the electrolyte membrane; and first and second reinforcing layers holding therebetween the electrolyte membrane and the first and second catalyst layers, a joint strength between the first catalyst layer and the first reinforcing layer being not less than a specific joint strength that suppresses expansion and contraction of the electrolyte membrane, a joint strength between the second catalyst layer and the second reinforcing layer being less than a specific joint strength that releases a stress due to expansion and contraction of the electrolyte membrane or zero, wherein before the first and second catalyst layers and the first and second reinforcing layers are joined together, the first catalyst layer and the first reinforcing layer meet both a condition that the resin volume content of the first catalyst layer is not less than 35% and a condition that the resin volume content of the first reinforcing layer is not less than 18%, and the second catalyst layer and the second reinforcing layer meet either a condition that the resin volume content of the second catalyst layer is less than 35% or a condition that the resin volume content of the second reinforcing layer is less than 18%.