Carbon sheet, gas diffusion electrode substrate and fuel cell

Patent metadata

Field	Value
Publication number	US-2017237079-A1
Application number	US-201515518879-A
Country	US
Kind code	A1
Filing date	Oct 7, 2015
Priority date	Oct 17, 2014
Publication date	Aug 17, 2017
Grant date	—

Abstract

A porous carbon sheet includes a carbon fiber and a binding material, wherein when in a measured surface depth distribution, a ratio of an area of a portion having a depth of 20 μm or less in a measured area of one surface is a surface layer area ratio X, and a ratio of an area of a portion having a depth of 20 μm or less in a measured area of another surface is a surface layer area ratio Y, the surface layer area ratio X is larger than the surface layer area ratio Y, and a difference between the surface layer area ratios is 3% or more and 12% or less.

First claim

1 .- 15 . (canceled)

16 . A porous carbon sheet comprising a carbon fiber and a binding material, wherein when in a measured surface depth distribution, a ratio of an area of a portion having a depth of 20 μm or less in a measured area of one surface is a surface layer area ratio X, and a ratio of an area of a portion having a depth of 20 μm or less in a measured area of another surface is a surface layer area ratio Y, the surface layer area ratio X is larger than the surface layer area ratio Y, and a difference between the surface layer area ratios is 3% or more and 12% or less.

17 . The carbon sheet according to claim 16 , wherein the surface layer area ratio X is 13% or more and 17% or less, and the surface layer area ratio Y is 9% or more and 13% or less.

18 . The carbon sheet according to claim 16 , wherein when a surface having the surface layer area ratio X is a surface X 1 , and a surface having the surface layer area ratio Y is a surface Y 1 , a surface roughness of the surface X 1 is smaller than a surface roughness of the surface Y 1 , and a difference between the surface roughnesses of the surfaces X 1 and Y 1 is 1 μm or more and 4 μm or less.

19 . The carbon sheet according to claim 16 , wherein when a surface having the surface layer area ratio X is a surface X 1 , surface roughness of the surface X 1 is 16 μm or less.

20 . A carbon sheet comprising a carbon fiber and a binding material, wherein when a surface having a larger covering rate on the surface by the carbon fiber and the binding material is a surface X 2 , and a surface having a smaller covering rate on the surface by the carbon fiber and the binding material is a surface Y 2 , a difference in the covering rate between the surface X 2 and the surface Y 2 is 5% or more and 20% or less.

21 . The carbon sheet according to claim 20 , wherein the covering rate on the surface X 2 is 70% or more and 90% or less, and the covering rate on the surface Y 2 is 50% or more and 75% or less.

22 . The carbon sheet according to claim 16 , wherein the carbon sheet includes a hydrophobic material, and where among layers obtained by dividing the carbon sheet in a through-plane direction thereof into three equal parts within a section extending from a surface having a 50% average fluorine intensity, which is closest to one surface, to a surface having a 50% average fluorine intensity, which is closest to another surface, one of a layer close to one surface and a layer close to the other layer, which has a larger average fluorine intensity, is a layer A, the other one of a layer close to one surface and a layer close to the other layer, which has a smaller average fluorine intensity, is a layer B, and a layer between the layer A and the layer B is a layer C, the average fluorine intensity of the layer decreases in the order of the layer A, the layer B and the layer C.

23 . The carbon sheet according to claim 22 , wherein the melting point of the hydrophobic material is 200° C. or more and 320° C. or less.

24 . The carbon sheet according to claim 18 , wherein the sliding angle of water at the surface Y 1 or the surface Y 2 is 40 degrees or less.

25 . The carbon sheet according to claim 16 , wherein when a sum of volumes of pores having a pore diameter of 1 to 100 μm is 100%, a sum of volumes of pores having a pore diameter of 50 to 100 μm is 17 to 50%, and
porosity ((ρt−ρb)/ρt) calculated from bulk density (ρb) and true density (ρt) is 75 to 87%.

26 . The carbon sheet according to claim 25 , wherein the diameter of a pore having the largest volume (peak diameter) in the diameter range of 1 to 100 μm is 30 to 50 μm.

27 . A gas diffusion electrode substrate, wherein when a surface having a surface layer area ratio X is a surface X 1 , the gas diffusion electrode substrate has a microporous layer on the surface X 1 or surface X 2 side of the carbon sheet according to claim 16 .

28 . A fuel cell comprising the gas diffusion electrode substrate according to claim 27 .

29 . A carbon sheet comprising a carbon fiber and a binding material, wherein when a sum of volumes of pores having a pore diameter of 1 to 100 μm is 100%, a sum of volumes of pores having a pore diameter of 50 to 100 μm is 17 to 50%, and
porosity ((ρt−ρb)/ρt) calculated from bulk density (ρb) and true density (ρt) is 75 to 87%.

30 . The carbon sheet according to claim 29 , wherein the diameter of a pore having the largest volume (peak diameter) in the diameter range of 1 to 100 μm is 30 to 50 μm.

Assignees

• Toray Industries

Inventors

• Tanimura Yasuaki
• Chida Takashi
• Sugahara Toru
• Utsunomiya Masamichi
• Kamae Toshiya
• Sode Katsuya
• Ando Takashi

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/0234 Primary

  Carbonaceous material · CPC title

• H01M8/0241

  Composites · CPC title

• H01M8/0243

  in the form of mixtures · CPC title

• H01M8/0245

  in the form of layered or coated products · CPC title