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A method of making a membrane-electrode-assembly (MEA) for a PEM/SPE fuel cell comprising applying a slurry of electrode-forming material directly onto a membrane-electrolyte film. The slurry comprises a liquid vehicle carrying catalyst particles and a binder for the catalyst particles. The membrane

A method of making a membrane-electrode-assembly (MEA) for a PEM/SPE fuel cell comprising applying a slurry of electrode-forming material directly onto a membrane-electrolyte film. The slurry comprises a liquid vehicle carrying catalyst particles and a binder for the catalyst particles. The membrane-electrolyte is preswollen by contact with the vehicle before the electrode-forming slurry is applied to the membrane-electrolyte. The swollen membrane-electrolyte is constrained against shrinking in the "x" and "y" directions during drying. Following assembly of the fuel cell, the MEA is rehydrated inside the fuel cell such that it swells in the "z" direction for enhanced electrical contact with contiguous electrically conductive components of the fuel cell.

대표청구항 ▼

[ What is claimed is:] [1.] In the process of making a membrane-electrode assembly for a PEM fuel cell said membrane-electrode-assembly having x and y directions perpendicular to each other in a plane of the membrane-electrode-assembly and a z direction through a thickness of the assembly normal to

[ What is claimed is:] [1.] In the process of making a membrane-electrode assembly for a PEM fuel cell said membrane-electrode-assembly having x and y directions perpendicular to each other in a plane of the membrane-electrode-assembly and a z direction through a thickness of the assembly normal to said plane, said process comprising the principal steps of (a) preparing an electrode-forming slurry comprising finely divided catalyst, a polymer binder for said catalyst and a liquid vehicle for the catalyst and binder, (b) coating a proton-conductive, polymeric membrane-electrolyte with said slurry to form a slurry-coated membrane, and (c) heating said slurry-coated membrane to remove said vehicle and cure said polymer binder, the improvement comprising:i. before said coating, contacting said membrane-electrolyte with said vehicle for a time sufficient to swell said membrane-electrolyte in the x, y and z directions, and thereby form a preswollen membrane-electrolyte;ii. constraining said preswollen membrane-electrolyte against shrinking in said x and y directions during drying;iii. coating the preswollen and constrained membrane with said slurry to form a slurry-coated membrane; andiv. heating the slurry-coated membrane to dry said slurry-coated membrane and cure said polymer binder, said heating being conducted while continuing said constraining to prevent the coated membrane from said shrinking.