Nonwoven carbon fiber fabric, process for producing nonwoven carbon fiber fabric, and polymer electrolyte membrane fuel cell

Patent metadata

Field	Value
Publication number	US-2017244113-A1
Application number	US-201515521831-A
Country	US
Kind code	A1
Filing date	Nov 20, 2015
Priority date	Dec 10, 2014
Publication date	Aug 24, 2017
Grant date	—

Abstract

An object of the present invention is to provide a nonwoven carbon fiber fabric suitable as a gas diffusion electrode, which achieves good water discharge performance and maintains high gas diffusibility even when electricity is generated in humid conditions. The present invention provides a nonwoven carbon fiber fabric which has ridges on at least one surface thereof and which is provided with a water repellent, the ridges having a pitch that is less than 500 μm.

First claim

1 . A nonwoven carbon fiber fabric which comprises ridges on at least one surface thereof and which is provided with a water repellent, the ridges having a pitch that is less than 500 μm.

2 . The nonwoven carbon fiber fabric according to claim 1 , wherein a ratio of ridge area is 0.1 to 0.9.

3 . The nonwoven carbon fiber fabric according to claim 1 , wherein a contact angle of water drop on the surface that has the ridges thereon is 100 degrees or more.

4 . The nonwoven carbon fiber fabric according to claim 1 , wherein the water repellent is localized at the ridges.

5 . A polymer electrolyte fuel cell comprising:
a gas diffusion electrode formed from the nonwoven carbon fiber fabric according to claim 1 ; and a separator that has channels in the form of parallel grooves, wherein the surface of the gas diffusion electrode which has the ridges thereon is in contact with a surface of the separator which has the channels therein.

6 . The polymer electrolyte fuel cell according to claim 5 , wherein the separator is stacked on the gas diffusion electrode in a manner such that a direction in which the channels extend is substantially parallel to a direction in which the ridges on the gas diffusion electrode extend.

7 . The polymer electrolyte fuel cell according to claim 5 , wherein the separator is stacked on the gas diffusion electrode in a manner such that a direction in which the channels extend intersects a direction in which the ridges on the gas diffusion electrode extend.

8 . The polymer electrolyte fuel cell according to claim 5 , wherein a contact angle of water drop on a wall of each of the channels in the separator is less than 100 degrees.

9 . The polymer electrolyte fuel cell according to claim 5 , wherein a tensile strength of the gas diffusion electrode is greater in a direction perpendicular to a direction in which the grooves in the separator extend than in the direction in which the grooves in the separator extend.

10 . A process for producing a nonwoven carbon fiber fabric, comprising the steps of:
A) forming ridges on a surface of a nonwoven carbon-fiber-precursor fabric by pressing, against the surface of the nonwoven carbon-fiber-precursor fabric, a shaping member having indentations and protrusions corresponding to the ridges; B) carbonizing the nonwoven carbon-fiber-precursor fabric obtained in step A) to obtain a nonwoven carbon fiber fabric; and C) giving a water repellent to the nonwoven carbon fiber fabric obtained in step B).

Assignees

• Toray Industries

Inventors

• Kajiwara Kentaro
• Shimoyama Satoru
• Horinouchi Ayanobu
• Horiguchi Tomoyuki

Classifications

• H01M8/1018

  Polymeric electrolyte materials · CPC title

• H01M8/0245

  in the form of layered or coated products · CPC title

• H01M8/0247

  characterised by the form (characterised by a channel configuration H01M8/0258) · CPC title

• H01M4/96 Primary

  Carbon-based electrodes · CPC title

• D06M15/256

  containing fluorine · CPC title