Movable anode fuel cell battery

• US 6,299,998 B1
• Filed: 03/15/1999
• Issued: 10/09/2001
• Est. Priority Date: 03/15/1999
• Status: Expired due to Fees

• Current Assignee: Reveo, Inc.
• Original Assignee: Reveo, Inc.
• Inventors: Tsai, Tsepin, Morris, William F.
• Primary Examiner(s): Nguyen, Nam
• Assistant Examiner(s): VERSTEEG, STEVEN H
• Application Number:
  US09/268,150
• Time in Patent Office: 939 Days
• Field of Search: 429/22, 429/26, 429/68, 429/69, 429/27
• US Class Current: 429/404
• CPC Class Codes: H01M 10/4214 Arrangements for moving electrodes or electrolyte
• 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: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell battery having an electrolyte, and a moving anode having anode material deposited on two sides of an electrically conductive substrate, which can be either a rotating anode disk, or a linearly moving anode, sandwiched between two air electrodes wherein the air electrodes each have at least one recharging portion and at least one discharging portion. The recharging portion of the air electrode is designed for optimum recharging and the discharging portion of the air electrode is designed for optimum discharging such that the fuel cell battery performs to its maximum ability. The recharging air electrode area can be larger than the discharging air electrode area for faster recharge times. The recharging air electrode can be operated at lower current densities to prevent anode densification, anode shape change and dendrite growth. Discharging the anode material on both sides of the anode increases the depth of the discharge and increases the battery'"'"'s capacity. The anode movement assures the anode is intermittently discharged to reduce passivation and further increase the depth of discharge. The motion of the anode helps to insure uniform replating during recharging. Further, the movement of the anode stirs the electrolyte assuring a uniform distribution of metal ions. As a result, the invention provides a metal/air Fuel Cell Battery with high energy density high power density and good rechargeability.

Claims

1. A rechargeable metal-air fuel cell battery (FCB) system comprising:

two air electrodes, each having at least one recharging portion and at least one discharging portion;

a movable anode having anode material disposed on two sides on electrically-conductive substrate, and being sandwiched between said two air electrodes with an electrolyte disposed between said anode material and said recharging portions and discharging portions.

2. The rechargeable metal-air FCB system of claim 1, further comprising:

a first electrically-conductive pathway coupled to the discharge air electrode portion of the two air electrodes,

a second electrically-conductive pathway coupled to the recharging air electrode portion of the two air electrodes,

a third electrically-conductive pathway coupled to the anode material of the metal anode,

wherein the first electrically-conductive pathway and third electrically-conductive pathway supply electrical current generated in the cell to a load when discharging the anode material, and wherein the second electrically-conductive pathway and third electrically-conductive pathway supply electrical current to the cell when recharging the anode material.

3. The rechargeable metal-air FCB system of claim 1, wherein said recharging portion of each said air electrode is designed for optimum recharging operations, and said discharging portion of said air electrode is designed for optimum discharging operations.

4. The rechargeable metal-air FCB system of claim 1, wherein the area of the recharging air electrode portion of each one of the two air electrodes is larger than the area of the discharging air electrode portions of each one of the two air electrode portions, thereby resulting in faster recharge times.

5. The rechargeable metal-air FCB system of claim 1, wherein said recharging air electrode is operated at lower current densities to prevent anode densification, anode shape change and dendrite growth.

6. The rechargeable metal-air FCB system of claim 1, wherein discharging said anode material on both sides of said movable anode increases depth of the discharge and increases capacity of said FCB system.

7. The rechargeable metal-air FCB system of claim 1, wherein movement of said movable anode assures said anode material is intermittently discharged to reduce passivation and further increase depth of discharge of said anode material.

8. The rechargeable metal-air FCB system of claim 1, wherein motion of said movable anode helps to insure uniform re-plating during recharging operations.

9. The rechargeable metal-air FCB system of claim 1, wherein movement of said anode stirs the electrolyte assuring a uniform distribution of metal ions.

10. The rechargeable metal-air FCB system of claim 1, wherein said movable anode is realized in the form of a rotating anode disk.

11. The rechargeable metal-air FCB system of claim 1, wherein said movable anode is realized in the form of a linearly moving anode, sandwiched between said two air electrodes.

12. The rechargeable metal-air FCB system of claim 1, wherein said discharge air electrode portion of the two air electrodes is used solely for discharging anode material.

13. The rechargeable metal-air FCB system of claim 1, wherein said recharging air electrode portion of the two air electrodes is used solely for recharging anode material.

14. A movable anode fuel cell battery (FCB) system comprising:

two air electrodes, each said electrode having at least one recharging air electrode portion and at least one discharge air electrode portion;

a metal anode having a substrate with metal anode material on either side of the substrate disposed proximate to and between the two air electrodes, wherein the metal anode is movable with respect to the two air electrodes,

an electrolyte for contacting the air electrodes and anode material to form a cell,

means for moving the anode material relative to the recharging air electrode portion for recharging the anode material and for moving the anode material relative to the discharging air electrode portion for discharging the anode material,

a first electrically-conductive pathway coupled to the discharge air electrode portion of the two air electrodes,

a second electrically-conductive pathway coupled to the recharging air electrode portion of the two air electrodes,

a third electrically-conductive pathway coupled to the anode material of the metal anode,

wherein the first electrically-conductive pathway and third electrically-conductive pathway supply electrical current generated in the cell to a load when discharging the anode material, and wherein the second electrically-conductive pathway and third electrically-conductive pathway supply electrical current to the cell when recharging the anode material.

15. The movable anode FCB system of claim 14, further comprising:

a controller operably coupled to the means for moving the anode material in order to control speed and direction of the anode'"'"'s motion.

16. The movable anode FCB system of claim 14, wherein:

area of the recharging air electrode portion for each one of the two air electrodes is greater than area of the discharging air electrode portion of each one of the two air electrodes such that recharging the anode will be faster than discharging and at a lower current density.

17. The movable anode FCB system of claim 14, further comprising:

a wiper blade attached to the air electrode, adjacent to the recharging air electrode portion, for contacting the anode such that dendrites on the anode are scraped off the anode by the wiper blade as the anode moves relative to the wiper blade.

18. The movable anode FCB system of claim 14, further comprising:

a mechanism for replacing said metal anode for mechanically recharging the fuel cell battery with new metal anodes.

19. The movable anode FCB system of claim 18, wherein:

said air electrodes have axle slots the metal anode has an axle that engages in the axle slots for removing and replacing metal anodes.

20. The movable anode FCB system of claim 14, wherein the anode material rotates relative the air electrodes.

21. The movable anode FCB system of claim 14, wherein the anode material moves linearly relative to the air electrodes.

22. The movable anode FCB system of claim 14, wherein a plurality of movable anode fuel cells operate simultaneously such that their combined electrical output is delivered to a load.

23. The movable anode FCB system of claim 22, wherein:

the means for moving the anode material comprises a motor that drives a common drive shaft connected to all anodes in the fuel cells such that the drive shaft moves all the anodes at the same time.

24. The movable anode FCB system of claim 22, wherein:

the means for moving the anode material comprises a separate motor for each anode fuel cell to drive the anode independently of other anodes.

25. The movable anode FCB system of claim 24, wherein a controller controls each motor such that speed and direction of each anode in each cell is controlled to maximize the efficiency of the fuel cell battery.

26. The movable anode FCB system of claim 22, wherein the plurality of cells are adjacent to each other and the recharging and discharging air electrodes for each cell are clocked with respect to the adjacent cells for air management.