Gas diffusion electrode substrate, and membrane electrode assembly and fuel cell equipped with same

Patent metadata

Field	Value
Publication number	US-10804544-B2
Application number	US-201515119163-A
Country	US
Kind code	B2
Filing date	Feb 17, 2015
Priority date	Feb 24, 2014
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

A gas diffusion electrode substrate that is used in a fuel cell and is constituted by an electrode substrate and microporous parts, in which a microporous part (A) is formed on one surface of the electrode substrate with a thickness in the range of 10 μm or more and 60 μm or less, and in the gas diffusion electrode substrate, the pore volume of pores with a pore size of 0.1 μm or more and less than 10 μm is within the range of 0.9 times or more and 5 times or less of the pore volume of pores with a pore size of 10 μm or more and less than 100 μm.

First claim

The invention claimed is:

1. A gas diffusion electrode substrate comprising:
an electrode substrate;
a first microporous portion comprising a carbon based filler and a water repellent agent which is formed on one surface of the electrode substrate with a thickness in the range of 10 μm or more and 60 μm or less; and
a second microporous portion comprising a carbon based filler and a water repellent agent which is impregnated in a part of the interior of the electrode substrate, wherein
the electrode substrate has pores with a size of 10 μm or more and less than 100 μm as volume of pores which corresponds to V(10-100): volume of pores with a size of 10 μm or more and less than 100 μm as measured by mercury porosimetry of the gas diffusion electrode substrate,
the first and second microporous portions have pores with a size of 0.1 μm or more and less than 10 μm as volume of pores which corresponds to V(0.1-10): volume of pores with a size of 0.1 μm or more and less than 10 μm measured by mercury porosimetry of the gas diffusion electrode substrate, and
V(0.1-10) is set in the range of 0.9 times or more and 5 times or less of V(10-100).

2. The gas diffusion electrode substrate according to claim 1 , wherein the thickness of the electrode substrate is in the range of 50 μm or more and 190 μm or less.

3. The gas diffusion electrode substrate according to claim 1 , wherein the volume of pores with a pore size of 0.03 μm or more and less than 0.3 μm is smaller than the volume of pores with a pore size of 0.3 μm or more and less than 3 μm.

4. The gas diffusion electrode substrate according to claim 1 , wherein V(0.1-10) is set in the range of one time or more and 5 times or less of V(10-100).

5. The gas diffusion electrode substrate according to claim 1 , wherein within the second microporous portion, the volume of pores with a pore size of 0.03 μm or more and less than 0.3 μm is smaller than the volume of pores with a pore size of 0.3 μm or more and less than 3 μm.

6. The gas diffusion electrode substrate according to claim 1 , wherein 20% or more and 70% or less of the pores of the electrode substrate interior are impregnated to form the second microporous portion.

7. The gas diffusion electrode substrate according to claim 1 , wherein the second microporous portion has a porosity in the range of 50% or more and 90% or less.

8. The gas diffusion electrode substrate according to claim 1 , wherein the porosity of the second microporous portion is larger than the porosity of the first microporous portion by 5% or more.

9. The gas diffusion electrode substrate according to claim 1 , wherein the carbon based filler of the second microporous portion has an aspect ratio of 30 or more and 5000 or less.

10. The gas diffusion electrode substrate according to claim 9 , wherein the carbon based filler of the second microporous portions is a fibrous carbon having a diameter of 1 nm or more and 500 nm or less.

11. The gas diffusion electrode substrate according to claim 1 , wherein the water repellent agent of the second microporous has a melting point of 200° C. or more and 320° C. or less.

12. The gas diffusion electrode substrate according to claim 1 , wherein the mass ratio of the water repellent agent to the carbon based filler of the second microporous portion is 5% by mass or more and 50% by mass or less, based on the carbon based filler.

13. The gas diffusion electrode substrate according to claim 1 , wherein the electrode substrate surface roughness on a first side including the first microporous portion is smaller than the electrode substrate surface roughness on a second opposite side by a difference of 1 μm or more and 5 μm or less.

14. A membrane electrode assembly having catalyst layers on both sides of the electrolyte membrane, and further having the gas diffusion electrode substrate as defined in claim 1 on the outer side of the catalyst layers.

15. A fuel cell having bipolar plates on both sides of the membrane electrode assembly as defined in claim 14 .

16. The gas diffusion electrode substrate according to claim 1 , wherein the electrode substrate comprises an electrically conductive porous material selected from the group comprising carbon fiber woven fabric, carbon fiber non-woven fabric, or carbon fiber papermaking substrate; or a metal porous material selected from the group comprising sintered foam metal, metal mesh or expanded metal.

Assignees

• Toray Industries

Inventors

• Tanimura Yasuaki
• Utsunomiya Masamichi
• Kamae Toshiya
• Okano Yasutaka

Classifications

• H01M8/0234

  Carbonaceous material · CPC title

• H01M8/0245 Primary

  in the form of layered or coated products · CPC title

• H01M8/0239

  Organic resins; Organic polymers · CPC title

• H01M8/0243 Primary

  in the form of mixtures · CPC title

• H01M8/1004

  characterised by membrane-electrode assemblies [MEA] (H01M8/12 takes precedence) · CPC title