Gas diffusion electrode substrate

Patent metadata

Field	Value
Publication number	US-10256477-B2
Application number	US-201515119325-A
Country	US
Kind code	B2
Filing date	Feb 17, 2015
Priority date	Feb 24, 2014
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

A gas diffusion electrode substrate that is used in a fuel cell, wherein a microporous layer constituted by a carbon based filler and a fluororesin is formed on one surface of the electrode substrate, the sliding angle of water on the surface on the opposite side of the surface on which the microporous layer is formed is 30 degrees or less, and the through-plane gas permeation resistance is 15 to 190 mmAq.

First claim

The invention claimed is:

1. A gas diffusion electrode substrate for a fuel cell, which comprises a microporous layer formed on a first surface of an electrode substrate, wherein the microporous layer comprises a carbon based filler and a fluororesin, and
wherein
a water sliding angle on a second surface of the electrode substrate, which is opposite to the first surface on which the microporous layer is formed, is 30 degrees or less, and
the through-plane gas permeation resistance of the gas diffusion electrode substrate is 15 to 190 mmAq at a flow rate of 58 cc/min/cm 2 .

2. The gas diffusion electrode substrate according to claim 1 , wherein the electrical resistance in the through-plane direction in a state where the gas diffusion electrode substrate is pressurized at 1 MPa is 7.4 mΩ·cm2 or less.

3. The gas diffusion electrode substrate according to claim 1 , wherein the carbon based filler is adhered to a carbon fiber surface that can be observed on the second surface of the electrode substrate, and the gas diffusion electrode substrate has a pore diameter of 10 μm or more on the second surface of the electrode substrate.

4. The gas diffusion electrode substrate according to claim 1 , wherein the carbon based filler is adhered to a carbon fiber surface that can be observed on the second surface of the electrode substrate, and the carbon based filler of the gas diffusion electrode substrate is a linear carbon having an aspect ratio of 30 to 5000.

5. The gas diffusion electrode substrate according to claim 1 , wherein the electrode substrate comprises carbon fiber, and 1 to 70% of the second surface of the electrode substrate surface is covered with the carbon based filler as observable from the second surface of the electrode substrate.

6. The gas diffusion electrode substrate according to claim 1 , wherein the thickness of the electrode substrate is 160 μm or less.

7. The gas diffusion electrode substrate according to claim 1 , wherein the surface roughness of the second surface of the electrode substrate is larger by 1.0 μm or more and 5.0 μm or less than the surface roughness of the first side of the electrode substrate where the microporous layer is formed.

8. The gas diffusion electrode substrate according to claim 1 , wherein the electrode substrate comprises carbon fiber, and the fluororesin is present on the second surface of the electrode substrate as observable from the second surface of the electrode substrate.

9. The gas diffusion electrode substrate according to claim 1 , wherein the fluororesin has a melting point of 200° C. or more and 320° C. or less.

10. The gas diffusion electrode substrate according to claim 1 , wherein the fluororesin is tetrafluoroethylene-hexa fluoro propylene copolymer (FEP).

11. The gas diffusion electrode substrate according to claim 1 , wherein the carbon based filler contains a vapor grown carbon fiber.

12. A membrane electrode assembly having catalyst layers on both sides of an electrolyte membrane, and having the gas diffusion electrode substrate as defined in claim 1 disposed on at least an outer side of one of the catalyst layers.

13. A fuel cell having bipolar plates on both sides of the membrane electrode assembly as defined in claim 12 .

14. A method for producing the gas diffusion electrode substrate as defined in claim 1 , comprising:
coating on one surface of an electrode substrate a carbon coating solution which comprises a carbon based filler, a fluororesin and a dispersion medium at a thickness of 160 μm or less so as to produce a coated electrode substrate, wherein the fluororesin is not coated before coating the carbon coating solution,
then holding the coated electrode substrate, for a period of 10 seconds or more and less than 5 minutes, so as to allow for infiltration of the carbon coating solution into the coated electrode substrate, and
subsequently drying and sintering the coated electrode substrate,
wherein the fluororesin is not coated before coating the carbon coating solution, or sintering is not performed before coating the carbon coating solution.

15. The method for producing the gas diffusion electrode substrate according to claim 14 , wherein the dispersion medium is water.

16. The method for producing the gas diffusion electrode substrate according to claim 14 , comprising, in the case that, before coating the carbon coating solution, sintering is not performed after coating the fluororesin, drying it at a temperature of 90° C. or more and less than 200° C., after coating the fluororesin.

Assignees

• Toray Industries

Inventors

• Utsunomiya Masamichi
• Tanimura Yasuaki
• Kamae Toshiya

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/0239

  Organic resins; Organic polymers · CPC title

• H01M8/0234

  Carbonaceous material · CPC title

• H01M8/0243 Primary

  in the form of mixtures · CPC title

• Y02P70/50

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