Perforated cylindrical fuel cells

• US 20040001988A1
• Filed: 06/28/2002
• Published: 01/01/2004
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: Graftech, Incorporated
• Original Assignee: Graftech, Incorporated
• Inventors: Reynolds, Robert Anderson III, Yazici, Mehmet Suha, Mercuri, Robert Angelo
• Granted Patent: US 6,960,402 B2
• Time in Patent Office: Days
• US Class Current: 429/34
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/921 Alloys or mixtures with metallic elements
• CPC Class Codes: H01M 8/0232 Metals or alloys
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/0252 tubular
• CPC Class Codes: H01M 8/0265 the reactant or coolant channels having varying cross sections
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

The invention relates to tubular fuel cells and methods of making such fuel cells. The inventive fuel cells include at least one fluid permeable structure having a plurality of perforations or channels. The perforations allow fluids, e.g., hydrogen or oxygen, to flow through the structure. The inventive methods include forming at least one perforated structure and forming the perforated structure into a tubular fuel cell or at least a potential component of a tubular fuel cell.

Claims

1. A fuel cell comprising:

an electrolyte;

a catalyst layer in communication with said electrolyte; and

a fluid permeable structure having a plurality of perforations said structure having at least a first major surface in communication with said catalyst, wherein a shape of said cell comprises tubular.

2. The fuel cell according to claim 1 wherein said structure comprises a material selected from stainless steel, titanium, carbon, graphite, graphite-polymer composite, or carbon-graphite composite.

3. The fuel cell according to claim 2 wherein said graphite comprises flexible graphite.

4. The fuel cell according to claim 3 wherein said structure further comprises at least a polymeric material.

5. The fuel cell according to claim 1 wherein a combination of said structure and said catalyst comprises at least one selected from an anode and a cathode.

6. The fuel cell according to claim 1 wherein said structure comprises an opposing second major surface and a cross sectional area of at least one perforation of said structure increases from said first major surface to said second major surface.

7. The fuel cell according to claim 6 wherein said structure comprises at least about two perforated flexible graphite layers.

8. The fuel cell according to claim 6 wherein a ratio of the cross sectional areas of said perforation of said first major surface to said second major surface comprises up to about 150:

1.

9. The fuel cell according to claim 1 wherein a fluid permeability of said structure comprises at least about 1 μ

l/cm²-s.

10. The fuel cell according to claim 1 wherein said cell is substantially devoid of an internal support element separate from said structure.

11. The fuel cell according to claim 1 wherein said cell is substantially devoid of a gas diffusion layer element separate from said structure.

12. The fuel cell according to claim 1 wherein said cell is substantially devoid of a field flow plate element separate from said structure.

13. The fuel cell according to claim 1 further comprising an interior passage along a longitudinal axis of said cell.

14. The fuel cell according to claim 1 wherein said cell consists of said electrolyte, said catalyst, said structure, a second catalyst in communication with said electrolyte, and a second fluid permeable structure having a plurality of perforations, said second structure in communication with said second catalyst.

15. The fuel cell according to claim 1 wherein said structure further comprises a carbon, graphite, or carbon-graphite coating on said first major surface of said structure, and said first surface facing with said catalyst.

16. The fuel cell according to claim 15 wherein said coating further comprises at least one polytetrafluoroethylene and a sulfonated polyfluoroaliphatic hydrogel.

17. The fuel cell according to claim 1 wherein said structure comprises flexible graphite and at least one of the group consisting of metal wire, metal shavings, metal foam, polymer foam, molded synthetic graphite, metal-alloy, and combinations thereof.

18. The fuel cell according to claim 1 wherein said structure comprises an unperforated perimeter region.

19. The fuel cell according to claim 1 further comprising a fluid distribution element positioned along an interior passage of said structure.

20. The fuel cell according to claim 1 further comprising a polyvinyldifluoride coating between said structure and said catalyst.

21. The fuel cell according to claim 1 wherein at least one of said perforations has a circular cross section on said first major surface and a rectangular cross section on a second major surface of said sheet.

22. The fuel cell according to claim 1 further comprising a gas diffusion layer between said sheet and said electrolyte, wherein a material of construction of said gas diffusion layer comprises flexible graphite and said gas diffusion layer having a coating of carbon particles on a surface of said gas diffusion layer, said coating facing said electrolyte.

27. The fuel cell according to claim 1 further comprising an outer surface of said cell comprises a polymeric material.

23. A membrane electrode assembly comprising:

an electrode and an ion exchange membrane in communication with said electrode, said electrode comprising at least one sheet of a compressed mass of expanded graphite particles having a plurality of transverse fluid channels passing through said sheet between first and second parallel opposed surfaces, wherein each channel comprises openings at both of said first and second surfaces and a shape of said assembly comprises tubular.

24. The membrane assembly according to claim 23 wherein at least one of said channels extends obliquely from said first opposed surface to said second opposed surface.

25. The membrane assembly according to claim 23 wherein at least one of said openings on said first surface has a larger cross-sectional area than at least one of said openings on said second surface.

26. The membrane assembly according to claim 24 wherein said electrode has an outer perimeter region substantially devoid of said channels.

28. A fuel cell comprising

graphite tube having at least on perforated region;

a catalyst applied to an exterior surface of said graphite tube;

an electrolyte in communication with said catalyst,

wherein a shape of said fuel cell comprises cylindrical.

29. The fuel cell according to claim 28 further comprising a second catalyst in communication with said electrolyte and a perforated sheet of flexible graphite surrounding said second catalyst.

30. The fuel cell according to claim 29 further comprising a fluid permeable polymeric layer applied to an exterior surface of said sheet of flexible graphite.