Membrane electrode assembly manufacturing process

Patent metadata

Field	Value
Publication number	US-10367217-B2
Application number	US-201514616968-A
Country	US
Kind code	B2
Filing date	Feb 9, 2015
Priority date	Feb 9, 2015
Publication date	Jul 30, 2019
Grant date	Jul 30, 2019

Abstract

A method of making a component of a membrane electrode assembly comprising the steps of forming an electrode on an air-permeable backer comprising ePTFE, depositing a mixture comprising ionomer and a water-insoluble alcohol onto said electrode, drying said mixture to form a protective ionomer layer, and depositing an ePTFE-reinforced ionomer layer onto said protective ionomer layer.

First claim

What is claimed is:

1. A method of making a component for a membrane electrode assembly comprising the steps of:
(a) providing an air-permeable backer;
(b) depositing an electrode onto said backer;
(c) depositing an aqueous wet layer comprising a fluoroionomer mixture comprising a water-insoluble alcohol and an ionomer onto said electrode;
(d) substantially drying said wet layer to form a protective ionomer layer; and
(e) depositing, after substantially drying said wet layer, a proton conducting composite wet layer onto said protective ionomer layer, wherein the proton conducting composite wet layer has an occlusive interior volume.

2. A method as defined in claim 1 wherein the air-permeable backer comprises an expanded polymer having release characteristics.

3. A method as defined in claim 2 wherein the expanded polymer is ePTFE.

4. A method as defined in claim 3 wherein said expanded polymer has a mass per area of less than about 16 g/m 2 of ePTFE.

5. A method as defined in claim 3 wherein said expanded polymer has a bubble point of greater than about 70 psi.

6. A method as defined in claim 3 wherein said air-permeable backer has a Z-strength sufficient to prevent cohesive failure of said ePTFE when said electrode is peeled off of said air-permeable backer.

7. A method as defined in claim 1 wherein the air-permeable backer is a gas diffusion layer.

8. A method as defined in claim 1 further comprising coupling a fabric to said backer.

9. A method as defined in claim 8 wherein said air-permeable backer is dimensionally stable within +/−4% throughout the manufacturing process.

10. A method as defined in claim 8 wherein said fabric comprises polyester.

11. A method as defined in claim 8 wherein said fabric has a thickness of less than about 0.006 inches.

12. A method as defined in claim 8 wherein said fabric has a mass/area of less than about 64 g/yd 2 .

13. A method as defined in claim 8 further comprising the step of bonding said fabric to said backer with an adhesive in a discontinuous pattern.

14. A method as defined in claim 13 wherein said fabric is dot-laminated to said backer with a urethane adhesive.

15. A method as defined in claim 13 wherein said adhesive is a solvent-resistant adhesive.

16. A method as defined in claim 1 wherein said ionomer is perfluorosulfonic acid (PFSA) ionomer.

17. A method as defined in claim 1 wherein said wet layer is aqueous and comprises greater than about 60 wt % water.

18. A method as defined in claim 1 wherein said wet layer is aqueous and comprises greater than about 90 wt % water.

19. A method as defined in claim 1 wherein said wet layer is aqueous and comprises less than about 3 wt % of said water-insoluble alcohol.

20. A method as defined in claim 1 wherein said wet layer is aqueous and comprises less than about 5 wt % of said water-insoluble alcohol.

21. A method as defined in claim 1 wherein said water-insoluble alcohol comprises hexanol.

22. A method as defined in claim 1 wherein said wet layer further comprises a water-soluble alcohol.

23. A method as defined in claim 22 wherein said wet layer comprises less than about 10 wt % of said water-soluble alcohol.

24. A method as defined in claim 22 wherein said water-soluble alcohol comprises glycol ether present in an amount of less than about 5 wt %.

25. A method as defined in claim 1 wherein said proton conducting composite wet layer comprises an ionomer.

26. A method as defined in claim 1 wherein said proton conducting composite wet layer comprises a reinforcement.

27. A method as defined in claim 26 wherein said reinforcement comprises an ePTFE membrane.

28. A method as defined in claim 1 further comprising the step of depositing an ionomer layer onto said proton conducting composite wet layer.

29. A method as defined in claim 28 further comprising the step of depositing another electrode onto said ionomer layer.

30. A method as defined in claim 1 further comprising the step of depositing another electrode onto said proton conducting layer.

31. A method as defined in claim 1 wherein said protective ionomer layer has a thickness of about 0.1 to about 25 microns.

32. A method as defined in claim 1 wherein said protective ionomer layer has a thickness of about 0.1 to about 10 microns.

33. A method as defined in claim 1 wherein said protective ionomer layer has a thickness of about 0.1 to about 3 microns.

Assignees

• Gore & Ass

Inventors

• Freese Donald T
• Busby F Colin

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M4/8828

  Coating with slurry or ink · CPC title

• B32B2375/00

  Polyureas; Polyurethanes · CPC title

• H01M2300/0085

  Immobilising or gelification of electrolyte · CPC title

• H01M8/106

  characterised by the chemical composition of the porous support · CPC title