Method of making fluid diffusion layers and electrodes having reduced surface roughness
AssigneeBallard Power Systems Inc.
InventorsJürgen Stumper, John Robert Gordon, Herwig Robert Haas, Kelvin Keen-Ven Fong
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Abstract
The present methods make fluid diffusion layers having reduced surface roughness. The methods used for adhering the loading material to the substrate surface can reduce the average surface roughness of the fluid diffusion layers, thereby reducing leaks in and damage to ion exchange membranes. When fluid diffusion layers and electrodes having reduced surface roughness are employed in membrane electrode assemblies, better reliability and performance are obtained. A method of calculating the surface roughness of a fluid diffusion layer may be used.
Claims56
A method of making a fluid diffusion layer comprising a substrate and a loading material adhered to the substrate, wherein the loading material is adhered to the substrate by the steps of:
- (a) applying a first loading composition comprising a first portion of the loading material to the substrate in a first applying step;
- and
- (b) applying a second loading composition comprising a second portion of the loading material to the substrate in a second applying step.
A method for making a fluid diffusion layer comprising a substrate and at least one loading material adhered to the substrate, wherein the loading material is adhered to the substrate by the steps of:
- (a) applying a loading composition to the substrate wherein the loading composition comprises the loading material,
- (b) partially drying the substrate and the loading composition applied thereto in a first drying step,
- (c) compacting the substrate and the loading material applied thereto in a compacting step, and
- (d) further drying the substrate and the loading material applied thereto in a second drying step.
A method for making a fluid diffusion layer comprising a substrate and a loading material adhered to the substrate, wherein the method comprises providing a release material, and the method comprises the steps of:
- (a) applying a loading composition comprising the loading material to at least one of the substrate and the release material so that a coated surface is formed;
- (b) contacting the substrate and the release material so that the coated surface is disposed between the substrate and the release material;
- (c) compacting the substrate, the release material, and the applied loading composition in a compacting step, and
- (d) drying the substrate, the release material, and the applied loading composition in a drying step, and
- (e) removing the release material from the substrate and the loading material.
Dependencies are inferred from the claim text.