Patent ID: 7452441

Claim:
A method for manufacturing a membrane electrode assembly, comprising: a process for preparing a electrolyte membrane and two gas diffusion layers, and a bonding process for forming the membrane electrode assembly by pressing a layered unit in which the electrolyte membrane is sandwiched between the two gas diffusion layers in such a way that catalyst layers are located in the interfaces between the electrolyte membrane and the two gas diffusion layers, wherein the bonding process is undertaken in a condition in which surfaces of the electrolyte membrane are temporarily liquefied or softened, wherein the bonding process is undertaken while the surfaces of the electrolyte membrane are temporarily liquefied or softened by use of a modifying substance, wherein the modifying substance is applied in a first amount to a first portion of surfaces of the electrolyte membrane that are in contact with a gas diffusion layer, and the modifying substance is either not applied, or applied in second amount less than the first amount to a second portion of the surfaces of the electrolyte membrane that are in contact with a gas diffusion layer, and wherein said second portion is adjacent to a corner of one of the gas diffusion layers.