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Abstract

An improved membrane electrode assembly for PEM fuel cells is provided. Catalyst layers (40, 44) are disposed, respectively, on both sides of the full planform proton exchange membrane (48). Gas diffusion layers (38, 50) are disposed, respectively, on sides of the catalyst layers (40, 44) not in communication with the full planform proton exchange membrane (48). Porous substrates (32, 34) are disposed, respectively, on sides of the gas diffusion layers (38, 50) not in communication with the catalyst layers (40, 44). The porous substrates (32, 34) are impregnated at their periphery with a sealant. The gas diffusion layers (38, 50) are coated with a sealant (60, 62) on respective sides thereof in regions which are in communication with sealant impregnated regions (36, 52) of the porous substrates (32, 34). The gas diffusion layers (38, 50), the porous substrates (32, 34), and the catalyst layers (40, 44) are co-extensive with the proton exchange membrane (48). The membrane electrode assembly (10) is continuously manufactured to eliminate step discontinuities and the associated strict tolerance requirements and resultant high scrap rates.

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First Claim