Gas diffusion electrode substrate, and membrane electrode assembly and fuel cell provided therewith

Patent metadata

Field	Value
Publication number	US-2017012291-A1
Application number	US-201515119314-A
Country	US
Kind code	A1
Filing date	Feb 17, 2015
Priority date	Feb 24, 2014
Publication date	Jan 12, 2017
Grant date	—

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, and a microporous part (B) is formed in a part, of the inside of the electrode substrate, the gas diffusion electrode substrate having a part in which the microporous part (B) is continuously present from the electrode substrate surface on the side on which the microporous part (A) is formed to a position near the electrode substrate surf ace on the opposite side, and a part in which pores are continuously distributed front the electrode substrate surface on the side on which the microporous part (A) is formed to the electrode substrate surface on the opposite side.

First claim

1 . 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, and a microporous part (B) is formed in a part of the inside of the electrode substrate, the gas diffusion electrode substrate having a part in which the microporous part (B) is continuously present from the electrode substrate surface on the side on which the microporous part (A) is formed to a position near the electrode substrate surface on the opposite side, and a part in which pores are continuously distributed from the electrode substrate surface on the side on which the microporous part (A) is formed to the electrode substrate surface on the opposite side.

2 . The gas diffusion electrode substrate according to claim 1 , wherein the microporous part (B) is impregnated in the part of the inside of the electrode substrate.

3 . The gas diffusion electrode substrate according to claim 1 , wherein the microporous part (B) has an areal weight within the range of 0.25 times or more and 0.55 times or less as the areal weight of the electrode substrate.

4 . The gas diffusion electrode substrate according to claim 1 , wherein the microporous part (B) contains a carbon based filler, and contains a carbon based filler having an aspect ratio of 30 or more and 5000 or less as the carbon based filler.

5 . The gas diffusion electrode substrate according to claim 4 , wherein the carbon based filler having an aspect ratio of 30 or more and 5000 or less is a fibrous carbon having an aspect ratio of 30 or more and 5000 or less.

6 . The gas diffusion electrode substrate according to claim 1 , wherein, in the cross section of the electrode substrate, the density of the part in which the microporous part (B) is continuously present is 1 part/mm or more.

7 . The gas diffusion electrode substrate according to claim 1 , wherein, in the cross section of the electrode substrate, the density of the part in which the pores are continuously distributed is 1 part/mm or more.

8 . The gas diffusion electrode substrate according to claim 1 , wherein the microporous part (B) is present in a form connecting to the microporous part (A), and the microporous part (B) is impregnated having a width of 10 μm or more in a depth of ¾ or more of the thickness of the electrode substrate from the electrode substrate surface on the side where the microporous part (A) is formed.

9 . The gas diffusion electrode substrate according to claim 1 , wherein the thickness of the microporous part (A) is 10 μm or more and 60 μm or less, and the thickness of the electrode substrate is 50 μm or more and 190 μm or less.

10 . The gas diffusion electrode substrate according to claim 1 , wherein the electrode substrate has, as compared to the surface roughness on the side where the microporous part (A) is formed, the surface roughness on the opposite side is larger with a difference of 1 μm or more and 5 μm or less.

11 . The gas diffusion electrode substrate according to claim 1 , wherein the microporous part (B) contains a water repellent agent having 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 microporous part (B) contains a water repellent agent and a carbon based filler, and the mass ratio of the water repellent agent 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 microporous part (B) has a porosity of 60% or more and 90% or less.

14 . The gas diffusion electrode substrate according to claim 1 , wherein the porosity of the microporous part (B) is larger than the porosity of the microporous part (A) by 5% or more.

15 . 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.

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

17 . The gas diffusion electrode substrate according to claim 2 , wherein the microporous part (B) has an areal weight within the range of 0.25 times or more and 0.55 times or less as the areal weight of the electrode substrate.

18 . The gas diffusion electrode substrate according claim 2 , wherein the microporous part (B) contains a carbon based filler, and contains a carbon based filler having an aspect ratio of 30 or more and 5000 or less as the carbon based filler.

19 . The gas diffusion electrode substrate according to claim 3 , wherein the microporous part (B) contains a carbon based filler, and contains a carbon based filler having an aspect ratio of 30 or more and 5000 or less as the carbon based filler.

20 . The gas diffusion electrode substrate according to claim 2 , wherein, in the cross section of the electrode substrate, the density of the part in which the microporous part (B) is continuously present is 1 part/mm or more.

Assignees

• Toray Industries

Inventors

• Tanimura Yasuaki
• Utsunomiya Masamichi
• Kamae Toshiya

Classifications

• H01M4/96

  Carbon-based electrodes · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/0239

  Organic resins; Organic polymers · CPC title

• H01M4/8663

  Selection of inactive substances as ingredients for catalytic active masses, e.g. binders, fillers · CPC title

• H01M4/92

  Metals of platinum group (H01M4/94 {, H01M4/9058} take precedence) · CPC title