Porous electrode substrate, method for manufacturing same, precursor sheet, membrane electrode assembly, and polymer electrolyte fuel cell

Patent metadata

Field	Value
Publication number	US-9825304-B2
Application number	US-201615077613-A
Country	US
Kind code	B2
Filing date	Mar 22, 2016
Priority date	Jan 27, 2011
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

According to the present invention, a porous electrode substrate with greater sheet strength, lower production cost, and excellent gas permeability and conductivity as well as its manufacturing method are provided. Also provided are a precursor sheet for forming such a substrate, and a membrane electrode assembly and a polymer electrolyte fuel cell containing such a substrate. The method for manufacturing such a porous electrode substrate includes the following steps [1]˜[3]: [1] a step for manufacturing a sheet material in which short carbon fibers (A) are dispersed; [2] a step for manufacturing a precursor sheet by adding a water-soluble phenolic resin and/or water-dispersible phenolic resin to the sheet material; and [3] a step for carbonizing the precursor sheet at a temperature of 1000° C. or higher. The present invention also relates to a porous electrode substrate obtained by such a manufacturing method as well as a precursor sheet to be used for manufacturing the substrate, a membrane electrode assembly and a polymer electrolyte fuel cell.

First claim

The invention claimed is:

1. A method for manufacturing a porous electrode substrate for a polymer electrolyte fuel cell, the method comprising:
manufacturing a sheet material in which short carbon fibers (A) are dispersed without using a binder;
continuously entangling the sheet material;
adding a water-soluble phenolic resin and a water-dispersible phenolic resin to the entangled sheet material, thereby forming a precursor sheet; and
carbonizing the precursor sheet at a temperature of 1000 C or higher.

2. The method according to claim 1 , further comprising:
drying the sheet material between the manufacturing and the adding.

3. The method according to claim 1 , further comprising:
drying the sheet material between the manufacturing and the entangling, the entangling and the adding, or both.

4. The method according to claim 1 ,
wherein the manufacturing is manufacturing a sheet material in which short carbon fibers (A) along with carbon fiber precursor short fibers (b1), fibrillar fibers (b2), or both are dispersed.

5. The method according to claim 1 , further comprising:
hot pressing the precursor sheet at a temperature of from 100° C. to 250° C. between the adding and the carbonizing.

6. The method according to claim 5 , further comprising:
drying the precursor sheet between the adding and the hot pressing.

7. The method according to claim 1 ,
wherein the sheet material obtained during the manufacturing comprises a water-soluble binder, and
an amount of the water-soluble binder in the sheet material is 10 g/m 2 or less.

8. The method according to claim 1 , wherein the adding is adding the water-soluble phenolic resin and water-dispersible phenolic resin to the sheet material by spraying, dripping, or flowing.

9. A porous electrode substrate manufactured by the method according to claim 1 .

Assignees

• Mitsubishi Rayon Co
• Mitsubishi Chem Corp

Inventors

• Tatsuno Hiroto
• Sumioka Kazuhiro
• Samejima Tadao

Classifications

• H01M4/8807

  Gas diffusion layers · CPC title

• D21H17/46

  obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• Y02P70/56

  Cross-Sectional Technologies · mapped topic

• D21H13/50

  Carbon fibres · CPC title

• H01M8/0234

  Carbonaceous material · CPC title