Method for producing fuel cell electrolyte membrane and method for producing membrane-electrolyte assembly

Abstract

An electrolyte membrane having recesses and projections on the surface thereof is obtained. In addition, a membrane-electrode assembly including the electrolyte membrane, in which the effective contact area between the electrolyte membrane surface and an electrode catalyst layer is increased, is obtained. An electrolyte membrane which includes a fluorine-based electrolyte is heated and pressed with the use of plates each having recesses and projections on the surface thereof such that recesses and projections are formed on the surface of the electrolyte membrane. Thereafter, the electrolyte membrane is subjected to a treatment for imparting ion exchange properties to an electrolyte polymer, such as hydrolysis, such that an electrolyte membrane having recesses and projections on the surface thereof is obtained. Electrode catalyst layers are separately laminated on the both surfaces of the electrolyte membrane such that a membrane-electrode assembly is obtained.

1 - 5 . (canceled) 
     
     
         6 . A method for producing a fuel cell electrolyte membrane, comprising:
 applying fluorine-based electrolyte particles to a surface of a porous reinforcing membrane;   impregnating the porous reinforcing membrane, the impregnating comprising heating the porous reinforcing membrane, to which electrolyte particles have been applied, with the use of a heated plate, melting the electrolyte particles, and allowing the electrolyte particles to impregnate the porous reinforcing membrane so as to obtain an electrolyte membrane;   pressing the electrolyte membrane with a plate having recesses and projections on the surface thereof so as to form recesses and projections on a surface of the electrolyte membrane; and   separating the plate and the electrolyte membrane from one another after the pressing.   
     
     
         7 . A method for producing a membrane-electrode assembly using a fuel cell electrolyte membrane produced by a method, comprising:
 applying fluorine-based electrolyte particles to a surface of a porous reinforcing membrane;   impregnating the porous reinforcing membrane, the impregnating comprising heating the porous reinforcing membrane, to which electrolyte particles have been applied, with the use of a heated plate, melting the electrolyte particles, and allowing the electrolyte particles to impregnate the porous reinforcing membrane so as to obtain an electrolyte membrane;   pressing the electrolyte membrane with a plate having recesses and projections on the surface thereof so as to form recesses and projections on a surface of the electrolyte membrane;   separating the plate and the electrolyte membrane from one another after the pressing;   applying electrode catalyst particles or a mixture of an electrode catalyst resin and fluorine-based electrolyte particles to the surface of the electrolyte membrane, on which recesses and projections have been formed, so as to obtain a laminate;   heating the laminate such that the electrode catalyst layer binds to the electrolyte membrane so as to be combined therewith; and   carrying out a treatment for imparting ion exchange properties to an electrolyte polymer constituting the electrolyte membrane.