Cathode cylinder for use in metal-air fuel cell battery systems and method of fabricating the same

• US 6,190,792 B1
• Filed: 08/10/1998
• Issued: 02/20/2001
• Est. Priority Date: 10/06/1997
• Status: Expired due to Fees

• Current Assignee: Reveo, Inc.
• Original Assignee: Reveo, Inc.
• Inventors: Faris, Sadeg M., Yao, Wayne, Tsai, Tsepin, Chen, Muguo, Legbandt, Thomas J.
• Primary Examiner(s): KALAFUT, STEPHEN J
• Application Number:
  US09/232,328
• Time in Patent Office: 925 Days
• Field of Search: 429/27, 429/68, 429/127, 429/306, 429/317, 429/254, 296/235
• US Class Current: 429/404
• CPC Class Codes: H01M 10/4214 Arrangements for moving electrodes or electrolyte
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 12/06 with one metallic and one gaseous electrode
• CPC Class Codes: H01M 12/08 composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
• CPC Class Codes: H01M 2004/024 Insertable electrodes
• CPC Class Codes: H01M 2300/0085 Immobilising or gelification of electrolyte
• CPC Class Codes: H01M 4/42 Alloys based on zinc
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: H01M 6/5011 for several cells simultaneously or successively
• CPC Class Codes: H01M 8/184 Regeneration by electrochemical means
• CPC Class Codes: H01M 8/186 by electrolytic decomposition of the electrolytic solution or the formed water product
• CPC Class Codes: H01M 8/22 Fuel cells in which the fuel is based on materials comprising carbon or oxygen or hydrogen and other elements; Fuel cells in which the fuel is based on materials comprising only elements other than carbon, oxygen or hydrogen
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

In an air-metal fuel cell battery (FCB) system, wherein metal-fuel tape, the ionically-conductive medium and the cathode structures are transported at substantially the same velocity at the locus of points at which the ionically-conductive medium contacts the moving cathode structure and the moving metal-fuel tape during discharging and recharging modes of operation. In a first generalized embodiment of the present invention, the ionically-conductive medium is realized as an ionically-conductive belt, and the metal-fuel tape, ionically-conductive belt, and movable cathode structure are transported at substantially the same velocity at the locus of points which the ionically-conducing belt contacts the metal-fuel tape and the cathode structure during system operation. In a second generalized embodiment of the present invention, the ionically-conductive medium is realized as a solid-state (e.g. gelatinous) film layer integrated with the metal-fuel tape. In a third generalized embodiment of the present invention, the ionically-conductive medium is realized as a solid-state film layer integrated with the movable cathode structure. By transporting the movable cathode structure, ionically contacting medium and metal-fuel tape within the system as described above, generation of frictional forces among such structures are minimized during system operation, and thus the damage to the cathode structure and metal-fuel tape is substantially reduced.

Claims

1. An ionically-conductive belt structure for use in a metal-air fuel cell battery (FCB) system, comprising:

a flexible belt portion for contacting a movable cathode structure and a length of metal-fuel tape transportable relative to said flexible belt portion during operation of said metal-air fuel cell battery system;

an ionically-conducting medium contained within said flexible belt portion, for supporting ionic conduction between said cathode structure and said metal-fuel tape during operation of said system; and

a hygroscopic agent.

2. The ionically-conductive belt structure of claim 1, wherein said flexible belt portion is made from a polymer material, and said ionically-conducting medium is a source of hydroxide ions.

3. The ionically-conductive belt structure of claim 2, wherein said polymer material is polyethylene oxide (POE).

5. The ionically-conductive belt structure of claim 1, wherein said hygroscopic agent is calcium chloride.

6. The ionically-conductive belt structure of claim 1, wherein the thickness of said flexible belt portion is the range of about 0.2 to about 0.5 millimeters.

4. The ionically-conductive belt structure of claim 68, wherein said source of hydroxide ions is potassium hydroxide (KOH).

7. A method of fabricating an ionically-conductive belt structure for use in a metal-air fuel cell battery system, said method comprising the steps of;

(a) dissolving a hydroxide ion source and a hygroscopic agent, into a solvent comprising water to produce a mixture;

(b) adding a polymer material to said mixture of step (a) to produce a coating material;

(c) applying a film of said coating material onto a substrate having a surface tension higher than said film applied in step (b);

(d) evaporating said solvent from said film coating so as to form a solid-state ionically-conductive membrane on said substrate; and

(e) removing said solid-state ionically-conductive membrane from said substrate;

(f) cutting said solid-state ionically-conductive membrane into a shape membrane; and

(g) joining the ends of said shaped membrane by an adhesive, ultra-sonic welding, or appropriate fasteners to form said solid-state ionically conductive belt structure.

8. The method of claim 7, wherein said polymer material is polyethylene oxide (POE).

9. The method of claim 8, wherein said substrate comprises poly alcohol (PVA) plastic material.

10. The method of claim 8, wherein said hydroxide ion source is potassium chloride (KOH).

11. The method of claim 10, wherein said hygroscopic agent is calcium chloride.

12. The method of claim 8, wherein said mixed solvent further comprises tetrahydrogen furan (THF).

13. The method of claim 7, wherein said polymer material is polyvinyl chloride (PVC).

14. The method of claim 13, wherein said hydroxide ion source is potassium chloride (KOH).

15. The method of claim 14, wherein said hygroscopic agent is calcium chloride.

16. The method of claim 13, wherein said substrate comprises polyvinyl alcohol (PVA, plastic material.

17. The method of claim 13, wherein said mixed solvent further comprises tetrahydrogen furan (THF).