Production method of catalyst ink for fuel cell, manufacturing method of catalyst layer for fuel cell and manufacturing method of membrane electrode assembly for fuel cell

Patent metadata

Field	Value
Publication number	US-9819030-B2
Application number	US-201414779409-A
Country	US
Kind code	B2
Filing date	Jan 14, 2014
Priority date	Mar 28, 2013
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

It becomes easy to regulate the storage modulus of the ionomer solution to be not lower than 150 Pa. The production method of catalyst ink for fuel cell includes steps of; (i) preparing a catalyst dispersion by mixing an electrode catalyst, water and an alcohol; (ii) preparing a gelated ionomer solution by mixing an ionomer and a solvent; and (iii) producing catalyst ink by mixing the catalyst dispersion and the gelated ionomer solution, wherein the step (ii) comprises concentration a step of concentrating the gelated ionomer solution.

First claim

The invention claimed is:

1. A production method of catalyst ink for fuel cell, comprising steps of:
(i) preparing a catalyst dispersion by mixing an electrode catalyst, water and an alcohol;
(ii) preparing a gelated ionomer solution by mixing an ionomer and a solvent; and
(iii) producing catalyst ink by mixing the catalyst dispersion and the gelated ionomer solution, wherein
the gelated ionomer solution in the step (ii) includes a solid content and a solvent content; and
the step (ii) comprises concentration a step of concentrating the gelated ionomer solution,
wherein the concentration step comprises a step of regulating a solubility parameter (SP value) of the solvent content to be not higher than 12.3.

2. The production method of the catalyst ink for fuel cell according to claim 1 ,
wherein the concentration step comprises a step of concentrating the gelated ionomer solution to increase percent by mass of the ionomer to 40 to 50%.

3. The production method of the catalyst ink for fuel cell according to claim 1 , further comprising a step of:
after the concentration step, adding an alcohol to the gelated ionomer solution to regulate percent by mass of a solid content in the gelated ionomer solution between 17.5 wt % and 25 wt %, inclusive.

4. The production method of the catalyst ink for fuel cell according to claim 1 , further comprising a step of:
after the concentration step, adding an alcohol to the gelated ionomer solution to regulate percent by mass of a solid content in the gelated ionomer solution between 20 wt % and 25 wt %, inclusive.

5. The production method of the catalyst ink for fuel cell according to claim 3 , the step (ii) further comprising a step of:
keeping the gelated ionomer solution at temperature of 70° C. to 90° C. for at least 4 hours.

6. The production method of the catalyst ink for fuel cell according to claim 5 ,
wherein retention time to keep the gelated ionomer solution at the temperature of 70° C. to 90° C. is at least 5 hours.

7. A manufacturing method of a catalyst layer for fuel cell, comprising a steps of:
applying the catalyst ink for fuel cell produced by the production method according to claim 1 , on a substrate; and
heating and drying the catalyst ink.

8. A manufacturing method of a membrane electrode assembly for fuel cell, comprising a step of:
transferring the catalyst layer for fuel cell manufactured by the manufacturing method according to claim 7 from the substrate to an electrolyte membrane by hot pressing at temperature of 130° C.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ishihara Noriaki
• Okumura Masao

Classifications

• H01M4/8882

  Heat treatment, e.g. drying, baking · CPC title

• H01M4/8828 Primary

  Coating with slurry or ink · CPC title

• C09D11/10

  based on artificial resins · CPC title

• H01M4/88

  Processes of manufacture · CPC title

• H01M4/8807

  Gas diffusion layers · CPC title