Carbon sheet, gas diffusion electrode substrate, wound body, and fuel cell

Patent metadata

Field	Value
Publication number	US-10637069-B2
Application number	US-201615767503-A
Country	US
Kind code	B2
Filing date	Oct 11, 2016
Priority date	Oct 22, 2015
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

The purpose of the present invention is to provide a carbon sheet that is suitably employed in a gas-diffusion-electrode substrate that has excellent flooding resistance and with which it is possible to suppress internal peeling of the carbon sheet. In order to achieve the aforementioned purpose, the present invention has the following configuration. Specifically, provided is a porous carbon sheet containing carbon fibers and a binder, wherein, in a section between a surface on one side of the carbon sheet and a surface on the other side thereof, when layers obtained by dividing, under compression, the carbon sheet into six equal parts in the thickness direction are assumed to be layer 1 , layer 2 , layer 3 , layer 4 , layer 5 , and layer 6 , in order starting from the layer including the surface on the one side to the layer including the surface on the other side, the layer in which the packing ratio under compression is the greatest is layer 2 , and the relationships of the packing ratios under compression among layer 2 , layer 3 , layer 4 , layer 5 , and layer 6 are such that layer 2 has the greatest packing ratio, and layer 3 has the second-greatest packing ratio.

First claim

The invention claimed is:

1. A porous carbon sheet comprising a carbon fiber and a binding material, wherein
the binding material has a concentration gradient in the thickness direction of the carbon sheet such that layers obtained by dividing the carbon sheet in a thickness direction into six equal parts under compression within a section extending from one surface to the other surface include a layer 1 , a layer 2 , a layer 3 , a layer 4 , a layer 5 and a layer 6 in this order from the layer including one surface to the layer including the other surface, a layer having the largest filling rate with the binding material under compression at a pressure of 0.15 MPa is the layer 2 ,
the filling rates of the layer 2 , the layer 3 , the layer 4 , the layer 5 and the layer 6 under compression satisfy the relationship of: the layer 2 has the largest filling rate, and the layer 3 has the second largest filling rate, and
the filling rates of the layer 2 , the layer 3 , the layer 4 , the layer 5 and the layer 6 under compression satisfy the relationship of: filling rate of layer 2 >filling rate of layer 3 >filling rate of layer 4 >filling rate of layer 5 >filling rate of layer 6 , and
wherein the carbon sheet is prepared from one prepreg.

2. The carbon sheet according to claim 1 , wherein the filling rate of the layer 2 is 10% or more and 50% or less.

3. The carbon sheet according to claim 1 , having a difference in filling rate between the layer 2 and the layer 1 (filling rate of layer 2 −filling rate of layer 1 ) of 5% or more.

4. The carbon sheet according to claim 1 , having differences in filling rate between the layer 2 and each of the layers 4 to 6 (filling rate of layer 2 −each of filling rates of layers 4 to 6 ) of each 5% or more.

5. The carbon sheet according to claim 1 , having a difference in filling rate between the layer 2 and the layer 3 (filling rate of layer 2 −filling rate of layer 3 ) of 3% or more.

6. The carbon sheet according to claim 1 , wherein when a surface included in the layer 6 is a surface 6 , the surface 6 has a surface coverage of 7% or less.

7. A gas diffusion electrode substrate, wherein the gas diffusion electrode substrate has a microporous layer on a surface 1 of a layer 1 of a porous carbon sheet comprising a carbon fiber and a binding material, wherein
the binding material has a concentration gradient in the thickness direction of the carbon sheet such that layers obtained by dividing the carbon sheet in a thickness direction into six equal parts under compression within a section extending from one surface to the other surface include the layer 1 , a layer 2 , a layer 3 , a layer 4 , a layer 5 and a layer 6 in this order from the layer including one surface to the layer including the other surface, a layer having the largest filling rate with the binding material under compression at a pressure of 0.15 MPa is the layer 2 ,
the filling rates of the layer 2 , the layer 3 , the layer 4 , the layer 5 and the layer 6 under compression satisfy the relationship of: the layer 2 has the largest filling rate, and the layer 3 has the second largest filling rate, and
the filling rates of the layer 2 , the layer 3 , the layer 4 , the layer 5 and the layer 6 under compression satisfy the relationship of: filling rate of layer 2 >filling rate of layer 3 >filling rate of layer 4 >filling rate of layer 5 >filling rate of layer 6 .

8. A wound body, which is the carbon sheet according to claim 1 wound up.

9. A wound body, which is the gas diffusion electrode substrate according to claim 7 wound up.

10. A fuel cell comprising the gas diffusion electrode substrate according to claim 7 .

Assignees

• Toray Industries

Inventors

• Sode Katsuya
• Sugahara Toru
• Ando Takashi

Classifications

• C04B35/83

  Carbon fibres in a carbon matrix · CPC title

• H01M4/8657

  layered · CPC title

• H01M4/8652 Primary

  as mixture · CPC title

• B32B5/28

  impregnated with or embedded in a plastic substance {(not used)} · CPC title

• H01M8/10

  Fuel cells with solid electrolytes · CPC title