Gas diffusion electrode base material, method for producing same, gas diffusion electrode, membrane electrode assembly and solid polymer fuel cell

Patent metadata

Field	Value
Publication number	US-2019165379-A1
Application number	US-201716312782-A
Country	US
Kind code	A1
Filing date	Jul 4, 2017
Priority date	Jul 14, 2016
Publication date	May 30, 2019
Grant date	—

Abstract

The purpose of the present invention is to improve water drainage performance of a gas diffusion electrode including a carbon fiber nonwoven fabric. The present invention provides a gas diffusion electrode base material essentially consisting of a carbon fiber nonwoven fabric, wherein the carbon fiber nonwoven fabric has an in-plane basis weight pattern in which high basis weight regions having a relatively high basis weight and low basis weight regions having a relatively low basis weight are arranged, and the carbon fiber nonwoven fabric has on at least one surface an uneven pattern in which recesses and projections are arranged, the uneven pattern being formed independently of the basis weight pattern.

First claim

1 . A gas diffusion electrode base material essentially consisting of a carbon fiber nonwoven fabric, wherein the carbon fiber nonwoven fabric has an in-plane basis weight pattern in which high basis weight regions having a relatively high basis weight and low basis weight regions having a relatively low basis weight are arranged, and the carbon fiber nonwoven fabric has on at least one surface an uneven pattern in which recesses and projections are arranged, the uneven pattern being formed independently of the basis weight pattern.

2 . The gas diffusion electrode base material according to claim 1 , wherein in the uneven pattern, the recess is formed over a boundary line between the low basis weight region and the high basis weight region, and 10% or more of the total length of the boundary line between the low basis weight region and the high basis weight region overlaps the recess in plan view.

3 . The gas diffusion electrode base material according to claim 1 , wherein at least one of the basis weight pattern and the uneven pattern is a regular pattern.

4 . The gas diffusion electrode base material according to claim 3 , wherein the basis weight pattern and the uneven pattern are regular patterns.

5 . The gas diffusion electrode base material according to claim 3 , wherein the basis weight pattern is a striped pattern.

6 . The gas diffusion electrode base material according to claim 1 , wherein an opposite surface at the same position in plan view as the projections on one surface is recessed.

7 . The gas diffusion electrode base material according to claim 1 , wherein broken fibers of carbon fibers are not observed on the wall surfaces of the unevenness in plan view.

8 . The gas diffusion electrode base material according to claim 1 , wherein at least some of carbon fibers that form the wall surfaces of unevenness is oriented in the height direction of the unevenness.

9 . The gas diffusion electrode base material according to claim 1 , further comprising a hydrophobic material.

10 . The gas diffusion electrode base material according to claim 1 , further comprising a microporous layer on a surface of the gas diffusion electrode base material.

11 . A gas diffusion electrode in which a catalyst layer is formed on a surface of the gas diffusion electrode base material according to claim 1 .

12 . A membrane electrode assembly comprising a polymer electrolyte membrane, a catalyst layer, and the gas diffusion electrode base material according to claim 1 .

13 . A polymer fuel cell obtained using the membrane electrode assembly according to claim 12 .

14 . A method for producing a gas diffusion electrode base material, the method comprising:
a step A of applying a water flow to a web including carbon fiber precursor fibers to obtain a carbon fiber precursor fiber nonwoven fabric having an in-plane basis weight pattern in which high basis weight regions having a relatively high basis weight and low basis weight regions having a relatively low basis weight are arranged; a step B of forming an uneven pattern by pressing a surface of the carbon fiber precursor fiber nonwoven fabric obtained in the step A with a member having unevenness; and a step C of carbonizing the carbon fiber precursor fiber nonwoven fabric provided with the uneven pattern in the step B.

15 . The method for producing a gas diffusion electrode base material according to claim 14 , wherein in the step A, a water flow is applied to the web at a pressure of 15 MPa or more.

Assignees

• Toray Industries

Inventors

• Kajiwara Kentaro
• Shimoyama Satoru
• Watanabe Fumitaka
• Tanimura Yasuaki

Classifications

• H01M8/0245

  in the form of layered or coated products · CPC title

• H01M8/0234 Primary

  Carbonaceous material · CPC title

• D04H1/4242

  Carbon fibres · CPC title

• H01M8/1004

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

• D04H1/495

  for formation of patterns, e.g. drilling or rearrangement · CPC title