Gas diffusion layer for fuel cell and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-9325022-B2
Application number	US-201214126634-A
Country	US
Kind code	B2
Filing date	May 31, 2012
Priority date	Jun 17, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

A gas diffusion layer for a fuel cell includes a gas diffusion layer substrate and a microporous layer formed on the surface of the gas diffusion layer substrate. The microporous layer is formed into a sheet-like shape including a binder and a carbon material containing at least scale-like graphite, and the sheet-like microporous layer is attached to the gas diffusion layer substrate. The gas diffusion layer for a fuel cell having such a configuration, prevents the components included in the microporous layer from entering the gas diffusion layer substrate, so as to ensure gas permeability. In addition, the scale-like graphite contained in the microporous layer as an electrically conductive material improves electrical conductivity and gas permeability. Accordingly, the gas diffusion layer contributes to an improvement in performance of a polymer electrolyte fuel cell.

First claim

The invention claimed is:

1. A gas diffusion layer for a fuel cell, comprising:
a gas diffusion layer substrate including carbon fiber; and
a microporous layer formed on a surface of the gas diffusion layer substrate, the microporous layer being formed into a sheet shape including:
a binder; and
a carbon material containing scale graphite and a spacer material,

wherein the spacer material is granular graphite having an average grain diameter in a range from 1 μm to 10 μm,
wherein a mass proportion of the granular graphite is in a range from 5% to 35% of the entire microporous layer, and
wherein the microporous layer is attached to the gas diffusion layer substrate.

2. The gas diffusion layer for a fuel cell according to claim 1 , wherein an average flat diameter of the scale graphite is in a range from 5 μm to 50 μm.

3. The gas diffusion layer for a fuel cell according to claim 2 , wherein the carbon material further contains an electrically conductive path material, and the electrically conductive path material is scale graphite having an average flat diameter of smaller than 5 μm.

4. The gas diffusion layer for a fuel cell according to claim 3 , wherein a mass proportion of the scale like scale graphite is in a range from 30% to 70% of the entire microporous layer.

5. The gas diffusion layer for a fuel cell according to claim 1 , wherein the carbon material further contains an electrically conductive path material, and the electrically conductive path material is acetylene black.

6. The gas diffusion layer for a fuel cell according to claim 5 , wherein a mass proportion of the acetylene black is in a range from 5% to 25% of the entire microporous layer.

7. The gas diffusion layer for a fuel cell according to claim 1 , wherein the carbon material further contains an electrically conductive path material, and the electrically conductive path material is carbon black having a specific surface area of 1000 m 2 /g or greater.

8. The gas diffusion layer for a fuel cell according to claim 7 , wherein a mass proportion of the carbon black is in a range from 1% to 5% of the entire microporous layer.

9. A membrane electrode assembly for a fuel cell, comprising:
an electrolyte membrane;
a catalyst layer stacked on the electrolyte membrane; and
the gas diffusion layer for a fuel cell according to claim 1 stacked on the catalyst layer.

10. The gas diffusion layer for a fuel cell according to claim 1 , wherein the binder binds the carbon material of the microporous layer together.

11. A method for manufacturing a gas diffusion layer for a fuel cell, comprising:
preparing ink for forming a microporous layer sheet including a binder and a carbon material;
applying the ink to a holding sheet and baking it to form the microporous layer sheet on the holding sheet;
removing the microporous layer sheet from the holding sheet; and
attaching the microporous layer sheet removed from the holding sheet to a gas diffusion layer substrate.

Assignees

• Okuyama Yozo
• Kuwata Shigemasa
• Kodama Kazufumi
• Nissan Motor

Inventors

• Okuyama Yozo
• Kuwata Shigemasa
• Kodama Kazufumi

Classifications

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• Y02E60/521

  Cross-Sectional Technologies · mapped topic

• H01M8/0245 Primary

  in the form of layered or coated products · CPC title

• H01M8/1002 Primary

  Electricity · mapped topic

• H01M8/0243

  in the form of mixtures · CPC title