Fuel-cell gas diffusion layer, and method of producing same

Patent metadata

Field	Value
Publication number	US-10249886-B2
Application number	US-201414764213-A
Country	US
Kind code	B2
Filing date	Feb 7, 2014
Priority date	Feb 13, 2013
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A fuel cell gas diffusion layer includes:
a porous carbon fiber base substrate containing discontinuous carbon fibers bonded to each other with carbide, and a porous layer containing at least carbonaceous particles, the porous carbon fiber base substrate having a porous layer (A) with a mean thickness t1 of 10 to 55 μm deposited on one surface A thereof, the porous carbon fiber base substrate being impregnated with porous layer (J) at least part of which is exposed at an opposite surface B, the porous carbon fiber base substrate having internal pores with a cross-sectional area accounting for 5% to 40% of the total cross section in a through-plane direction, at least porous layer (A) and porous layer (J) both having a void percentage of 50% to 85%, the porous carbon fiber base substrate having a thickness of 60 to 300 μm, and the porous carbon fiber base substrate having a bulk density of 0.20 to 0.45 g/cm 3 .

First claim

The invention claimed is:

1. A fuel cell gas diffusion layer comprising:
a porous carbon fiber base substrate
1) consisting of discontinuous carbon fibers bonded to each other with carbonized material,
2) being impregnated with porous material (J) at least part of which is exposed at one surface B thereof,
3) having internal pores with a cross-sectional area accounting for 5% to 40% of the total cross section in a through-plane direction with carbonaceous particles in the porous carbon fiber base substrate, and
4) having a thickness of 60 to 300 μm and a density of 0.20 to 0.45 g/cm 3 , and

a layer (A) containing voids, the layer (A) having a mean thickness t1 of 10 to 55 μm and consisting of 1) carbonaceous particles, and 2) a hydrophobic polymer deposited on an opposite surface A of the porous carbon fiber base substrate,
at least layer (A) and porous material (J) both having a void percentage of 50% to 85%.

2. The fuel cell gas diffusion layer as described in claim 1 , wherein layer (A) and porous material (J) have different constitutions.

3. The fuel cell gas diffusion layer as described in claim 1 , wherein layer (A) and porous material (J) have the same constitution.

4. The fuel cell gas diffusion layer as described in claim 1 , further comprising layer (B) with a mean thickness t2 of 0 to 20 μm deposited on the opposite surface B.

5. The fuel cell gas diffusion layer as described in claim 1 , wherein layer (B) and porous material (J) utilize the same dispersion liquid.

6. The fuel cell gas diffusion layer as described in claim 1 , wherein the porous carbon fiber base substrate and the porous layers further contain a hydrophobic polymer.

7. The fuel cell gas diffusion layer as described in claim 6 , wherein the hydrophobic polymer is distributed unevenly in the porous carbon fiber base substrate, with a larger concentration near the layer (A).

8. The fuel cell gas diffusion layer as described in claim 1 , wherein the carbonaceous particles contained in the porous layer account for 5 to 95 mass %.

9. The fuel cell gas diffusion layer as described in claim 1 , wherein the carbonaceous particles contain at least carbon black.

10. The fuel cell gas diffusion layer as described in claim 1 , wherein the void percentage of layer (A) is higher than the void percentage of layer (B) or that of porous material (J).

11. The fuel cell gas diffusion layer as described in claim 1 , wherein crack frequency in the layer (A) is smaller than crack frequency in the porous material (J).

12. The fuel cell gas diffusion layer as described in claim 1 , wherein crack frequency in the layer (A) is one per square millimeter or less.

13. A fuel cell gas diffusion layer comprising:
a porous carbon fiber base substrate
1) consisting of discontinuous carbon fibers bonded to each other with carbonized material,
2) being impregnated with porous material (J) at least part of which is exposed at one surface B thereof,
3) having internal pores with a cross-sectional area accounting for 5% to 40% of the total cross section in a through-plane direction with carbonaceous particles in the porous carbon fiber base substrate,
4) having a thickness of 60 to 300 μm and a density of 0.20 to 0.45 g/cm 3 , and
a layer (A) containing voids, the layer (A) having a mean thickness t1 of 10 to 55 μm and consisting of 1) carbonaceous particles, and 2) a hydrophobic polymer deposited on an opposite surface A of the porous carbon fiber base substrate,
at least layer (A) and porous material (J) both having a void percentage of 50% to 85%, and porous material (J) is a part of the layer (A).

Assignees

• Toray Industries

Inventors

• Okano Yasutaka
• Antoku Koichi
• Wadahara Eisuke

Classifications

• H01M8/0239 Primary

  Organic resins; Organic polymers · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M4/8807

  Gas diffusion layers · CPC title

• H01M8/0245

  in the form of layered or coated products · CPC title

• H01M8/0241

  Composites · CPC title