METAL-AIR FUEL CELL BATTERY SYSTEM EMPLOYING HYDROSTATIC FORCES TO ENABLE SIMULTANEOUS TRANSPORT OF METAL-FUEL TAPE, MOVABLE CATHODE STRUCTURE, AND IONICALLY-CONDUCTIVE MEDIUM THERETHROUGH DURING SYSTEM OPERATION

• US 6,403,244 B2
• Filed: 08/12/1998
• Issued: 06/11/2002
• 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:
  US09/133,166
• Publication Number:
  US 20010007725A1
• Time in Patent Office: 1,399 Days
• Field of Search: 429/27, 429/63, 429/68, 429/69, 429/80, 429/127
• 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

Abstract

In an air-metal fuel cell battery (FCB) system, wherein a movable cathode structure is mounted within a housing through which metal-fuel tape is transported along a predetermined path while an ionically-conductive medium is disposed between the metal-fuel tape and the movable cathode structure. In illustrative embodiments, the movable cathode structure is realized as a rotatable cathode cylinder, and a transportable cathode belt. The ionically-conductive medium is realized as a solid-state ionically-conductive film applied to the cathode structures and/or metal-fuel tape, as well as ionically-conductive belt structures. During system operation, the metal-fuel tape and/or the ionically-conductive medium are wetted in order create sufficient surface tension, and thus sufficient hydrostatic forces, between the metal-fuel tape and ionically-conductive medium and between the ionically-conductive medium and the movable cathode structure, to enable the movable cathode structure, ionically-conductive medium and metal-fuel tape to move at substantially the same velocity at points of contact therebetween while only one or these three moving system components are being actively driven by a transport mechanism. By virtue of the present invention, it is possible to transport the moving components of the FCB system using a various types of low power devices including, for example, miniature electrical and spring-driven motors, while substantially reducing the likelihood of damage thereto during system operation.

Claims

1. A metal-air fuel cell battery system for generating electrical power, comprising:

a movable cathode structure mounted within a housing to enable movement about a closed path;

a supply of metal-fuel tape transportable relative to said movable cathode structure;

a solid-state ionically-conductive medium transportable relative to both said movable cathode structure and said metal-fuel tape and disposed between said movable cathode structure and said metal-fuel tape during system operation, for contacting said movable cathode structure and said metal-fuel tape during system operation, and supporting ionic conduction between said movable cathode structure and said metal-fuel tape during system operation;

a transport mechanism for actively transporting at least one of said movable cathode structure, said metal-fuel tape and said ionically-conductive medium relative to said housing; and

a surface tension maintenance mechanism including a dispenser and an applicator for applying a coating of water (H2O) and/or an electrolyte make-up solution to the surface of said metal-fuel tape and/or said ionically-conductive medium during system operation so that, during system operation, wetting occurs between (i) said ionically-conductive medium and said metal-fuel tape, and (ii) said ionically-conductive medium and said movable cathode structure, thereby maintaining a sufficient level of surface tension between (i) said ionically-conductive medium and said metal-fuel tape and/or (ii) said ionically-conductive medium and said movable cathode structure during system operation so as to cause said metal-fuel tape, said ionically-conductive medium and said movable cathode structure to move at substantially the same velocity at points of contact therebetween, by virtue of hydrostatic forces created by said maintained level of surface tension.

2. The metal-air fuel cell battery system of claim 1, wherein the thickness of said coating of water and/or said electrolyte make-up solution depends on the speed and water absorption properties of said metal fuel tape.

3. The metal-air fuel cell battery system of claim 1, wherein said wetting device comprises a mechanism for dispensing and applying said coating of water and/or said electrolyte make-up solution to the surface of said metal-fuel tape and/or said ionically-conductive medium.

4. The metal-air fuel cell battery system of claim 1, wherein said transport mechanism comprises a motor driven by either mechanical, electrical, or pneumatic forces.

5. The metal-air fuel cell battery system of claim 4, wherein said motor is driven by a spring mechanism.

6. The metal-air fuel cell battery system of claim 1, wherein said movable cathode structure is cylindrically shaped and has a hollow center permitting air flow therethrough.

7. The metal-air fuel cell battery system of claim 1, wherein said ionically-conductive medium is an ionically-conductive belt structure transported between said movable cathode structure and at least a portion of said metal-fuel tape.

8. The metal-air fuel cell battery system of claim 1, wherein said movable cathode structure is a cathode belt structure.

9. The metal-air fuel cell battery system of claim 1, wherein said movable cathode structure is a cathode belt structure, and said ionically-conductive medium is an ionically-conductive belt structure disposed between at least a portion of said cathode belt structure and said metal-fuel tape.

10. The metal-air fuel cell battery system of claim 1, wherein only one of said movable cathode structure and said metal-fuel tape is actively transported relative to said housing during system operation.

11. The metal-air fuel cell battery system of claim 1, wherein said solid-state ionically-conductive medium comprises an ionically-conductive belt.

12. The metal-air fuel cell battery system of claim 11, wherein said ionically-conductive belt is made from an open-cell polymer material having a porous structure.

13. The metal-air fuel cell battery system of claim 11, wherein said ionically-conductive belt further comprises a solid-state film formed on a substrate material having a higher surface tension than the solid-state film.

14. The metal-air fuel cell battery system of claim 13, wherein said solid-state film is formed by:

depositing a solution comprising liquid electrolyte and solvent on said substrate material, and evaporating the solvent.

15. The metal-air fuel cell battery system of claim 13, wherein said substrate material is polyvinyl alcohol (PVA).

16. A method of producing electrical power from a metal-air fuel cell battery system having a housing, a movable cathode structure, a supply of a metal-fuel tape, and an source of ionically-conductive medium for supporting ion transport between said movable cathode structure and said metal-fuel tape during system operation, said method comprising the steps of:

(a) providing a solid-state ionically conductive medium transportable relative to both said movable cathode structure and said metal-fuel tape;

(b) arranging said moving cathode structure and said supply of metal-fuel tape within said housing so that said ionically-conductive medium is disposed in physical contact with said movable cathode structure and said metal-fuel tape; and

(c) while actively transporting at least one of said movable cathode structure, said metal-fuel tape and said ionically-conductive medium relative to said housing, applying a coating of water (H2O) and/or an electrolyte make-up solution from a dispenser in fluid communication with an applicator to the surface of said metal-fuel tape and/or said ionically-conductive medium during system operation so that, during system operation, wetting occurs between (i) said ionically-conductive medium and said metal-fuel tape, and (ii) said ionically-conductive medium and said movable cathode structure, thereby maintaining a sufficient level of surface tension between said ionically-conductive medium and the metal-fuel tape and said ionically-conductive medium and said movable cathode structure during system operation causing said metal-fuel tape, said ionically-conductive medium and said movable cathode structure to move at substantially the same velocity at points of contact therebetween by hydrostatic forces created by said maintained level of surface tension.

17. The method of claim 16, wherein said movable cathode structure is cylindrically shaped and has a hollow center permitting air flow therethrough.

18. The method of claim 16, wherein said movable cathode structure is a cathode belt structure.

19. The method of claim 16, wherein said movable cathode structure is a cathode belt structure, and said ionically-conductive medium is an ionically-conductive belt structure disposed between at least a portion of said cathode belt structure and said metal-fuel tape.

20. The method of claim 16, where during step (a) only one of said movable cathode structure and said metal-fuel tape is actively transported relative to said housing during system operation.

21. The method of claim 16, wherein said solid-state ionically-conductive medium comprises an ionically-conductive belt.

22. The method of claim 21, wherein said ionically-conductive belt is made from an open-cell polymer material having a porous structure.

23. The method of claim 21, wherein said ionically-conductive belt further comprises a solid-state film formed on a substrate material having a higher surface tension than the solid-state film.

24. The method of claim 23, wherein said solid-state film is formed by:

depositing a solution comprising liquid electrolyte and solvent on said substrate material, and evaporating the solvent.

25. The method of claim 23, wherein said substrate material is polyvinyl alcohol (PVA).