Carbon-fiber nonwoven cloth and gas diffusion electrode for polymer electrolyte fuel cell using same, polymer electrolyte fuel cell, method for manufacturing carbon-fiber nonwoven cloth, and composite sheet

Patent metadata

Field	Value
Publication number	US-2015318558-A1
Application number	US-201314439954-A
Country	US
Kind code	A1
Filing date	Nov 27, 2013
Priority date	Dec 5, 2012
Publication date	Nov 5, 2015
Grant date	—

Abstract

Provided is a carbon-fiber nonwoven cloth with low resistance to gases or liquids passing through, and low resistance in the thickness direction to heat or electricity, which is particularly appropriate for a gas diffusion electrode of a polymer electrolyte fuel cell; the cloth having an air gap with a diameter of at least 20 μm, at least some of the carbon fibers being continuous from one surface to the other surface, and the apparent density being 0.2-1.0 g/cm 3 , or, having an air gap with a diameter of at least 20 μm and at least some of the carbon fibers being mutually interlaced, and further, at least some of the carbon fibers being oriented toward the thickness direction and the apparent density being 0.2-1.0 g/cm 3 .

First claim

1 . A carbon-fiber nonwoven cloth, which comprises carbon fibers and has two surfaces, and which has voids each having a diameter of 20 μm or more and has an apparent density of 0.2 to 1.0 g/cm 3 , at least one part of the carbon fibers being continuous from one of the surfaces to the other surface.

2 . A carbon-fiber nonwoven cloth, which comprises carbon fibers and which has voids each having a diameter of 20 μm or more and an apparent density of 0.2 to 1.0 g/cm 3 , at least one part of the carbon fibers being entangled with each other, and at least one part of the carbon fibers being oriented in the thickness direction of the nonwoven cloth.

3 . The carbon-fiber nonwoven cloth according to claim 1 , wherein the voids, the diameter of which is 20 μm or more, are used as a gas channel.

4 . The carbon-fiber nonwoven cloth according to claim 1 , which is usable as a gas diffusion electrode for a polymer electrolyte fuel cell.

5 . A gas diffusion electrode for a polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 1 is used.

6 . A polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 1 is used.

7 . A method for manufacturing a carbon-fiber nonwoven cloth, comprising: a bonding step of laminating a web comprising fibers each having a carbonization yield of 30% or more, and a fiber fabric having a carbonization yield of 20% or less to each other, and bonding the web and the fiber fabric to each other by needle punching and/or water jet punching; a hot-pressing step of hot-pressing the web and the fiber fabric bonded to each other to produce a composite sheet; and a firing step of firing the composite sheet to be made into a carbon fiber form.

8 . The method for manufacturing a carbon-fiber nonwoven cloth according to claim 7 , wherein the web is laminated onto one surface of the fiber fabric in the bonding step.

9 . The method for manufacturing a carbon-fiber nonwoven cloth according to claim 7 , wherein in the firing step, the composite sheet, which has been made into the carbon fiber form by the once-performed firing, is subjected to a carbonizing treatment of bonding a binder precursor having a carbonization yield of 30% or more to the composite sheet, and firing the binder-precursor-bonded composite sheet again.

10 . A composite sheet, comprising a web comprising fibers each having a carbonization yield of 30% or more, and a fiber fabric having a carbonization yield of 20% or less, wherein at least one part of the fibers having a carbonization yield of 30% or more penetrate the fiber fabric having a carbonization yield of 20% or less.

11 . The carbon-fiber nonwoven cloth according to claim 2 , wherein the voids, the diameter of which is 20 μm or more, are used as a gas channel.

12 . The carbon-fiber nonwoven cloth according to claim 2 , which is usable as a gas diffusion electrode for a polymer electrolyte fuel cell.

13 . The carbon-fiber nonwoven cloth according to claim 3 , which is usable as a gas diffusion electrode for a polymer electrolyte fuel cell.

14 . A gas diffusion electrode for a polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 2 is used.

15 . A gas diffusion electrode for a polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 3 is used.

16 . A gas diffusion electrode for a polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 4 is used.

17 . A polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 2 is used.

18 . A polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 3 is used.

19 . A polymer electrolyte fuel cell, wherein the carbon-fiber nonwoven cloth recited in claim 4 is used.

20 . The method for manufacturing a carbon-fiber nonwoven cloth according to claim 8 , wherein in the firing step, the composite sheet, which has been made into the carbon fiber form by the once-performed firing, is subjected to a carbonizing treatment of bonding a binder precursor having a carbonization yield of 30% or more to the composite sheet, and firing the binder-precursor-bonded composite sheet again.

Assignees

• Toray Industries

Inventors

• Kajiwara Kentaro
• Shimoyama Satoru
• Horiguchi Tomoyuki

Classifications

• B32B5/26

  another layer {next to it} also being fibrous or filamentary {(relative arrangement of fibres or filaments of different layers B32B5/12)} · CPC title

• H01M4/8875

  Methods for shaping the electrode into free-standing bodies, like sheets, films or grids, e.g. moulding, hot-pressing, casting without support, extrusion without support · CPC title

• H01M2300/0082

  Organic polymers · CPC title

• B32B2262/106

  Carbon fibres, e.g. graphite fibres · CPC title

• H01M4/8626 Primary

  characterised by the form · CPC title