Alkaline fuel cell pack with gravity fed electrolyte circulation and water management system

• US 20040161652A1
• Filed: 02/12/2003
• Published: 08/19/2004
• Est. Priority Date: 02/12/2003
• Status: Abandoned Application

• Current Assignee: Texaco Ovonic Fuel Cell, LLC
• Original Assignee: Texaco Ovonic Fuel Cell, LLC
• Inventors: Gradinarova, Latchezara, Wang, Hong, Ovshinsky, Stanford R., Faguy, Peter, Venkatesan, Srinivasan, Menjak, Zdravko, Dhar, Subhash K., Menjak, Ana
• Application Number:
  US10/364,978
• Publication Number:
  US 20040161652A1
• Time in Patent Office: Days
• US Class Current: 429/34
• CPC Class Codes: H01M 8/0271 Sealing or supporting means around electrodes, matrices or membranes
• CPC Class Codes: H01M 8/0273 with sealing or supporting means in the form of a frame
• CPC Class Codes: H01M 8/2457 with both reactants being gaseous or vaporised
• CPC Class Codes: H01M 8/2459 Comprising electrode layers with interposed electrolyte compartment with possible electrolyte supply or circulation
• CPC Class Codes: H01M 8/247 Arrangements for tightening a stack, for accommodation of a stack in a tank or for assembling different tanks
• CPC Class Codes: H01M 8/2483 characterised by internal manifolds
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An ambient temperature alkaline fuel cell pack supplied with a non-forced electrolyte and air stream which are circulated through the fuel cell pack via thermal convection resulting from heat produced during the reactions at the hydrogen and air electrodes.

Claims

1. A fuel cell pack comprising:

a fuel cell stack including at least one hydrogen electrode having a hydrogen contacting surface and an electrolyte contacting surface and at least one air electrode having an air contacting surface and an electrolyte contacting surface;

a convectional electrolyte circulating loop for supplying a stream of electrolyte to said fuel cell stack.

2. The fuel cell pack according to claim 1, wherein said electrolyte circulating loop comprises:

an electrolyte reservoir positioned at a height higher than the height of said fuel cell stack;

wherein said electrolyte reservoir

     1) is in fluid communication with said fuel cell stack,

     2) provides a stream of cooled electrolyte to said fuel cell stack via a gravity feed, and

     3) receives a heated stream of electrolyte from said fuel cell stack via thermal convection.

3. The fuel cell pack according to claim 2, wherein said electrolyte contacting surface of said air electrodes and said electrolyte contacting surfaces of said hydrogen electrodes are adjacent an electrolyte chamber.

4. The fuel cell pack according to claim 3, wherein said electrolyte chamber is formed between said electrolyte contacting surface of said air electrodes and said electrolyte contacting surfaces of said hydrogen electrodes.

5. The fuel cell pack according to claim 3, wherein said cooled stream of electrolyte enters the bottom of said electrolyte chamber and said heated stream of electrolyte exits the top of said electrolyte chamber via thermal convection.

6. The fuel cell pack according to claim 1, wherein each of said hydrogen contacting surfaces of said hydrogen electrodes are adjacent a hydrogen chamber.

7. The fuel cell pack according to claim 6, wherein said hydrogen chamber is formed between said hydrogen contacting surfaces of two of said hydrogen electrodes.

8. The fuel cell pack according to claim 6, wherein an ambient pressure stream of hydrogen is supplied to said hydrogen chamber at a rate equal to the consumption of hydrogen by said fuel cell stack.

9. The fuel cell pack according to claim 1, wherein each of said hydrogen electrodes are sealed in a hydrogen electrode frame exposing said hydrogen contacting surface and said electrolyte contacting surface of said hydrogen electrode.

10. The fuel cell pack according to claim 1, wherein each of said air contacting surfaces of said air electrodes are adjacent an air flow-through passageway.

11. The fuel cell pack according to claim 10, wherein a non-forced stream of air enters said air flow-through passageway via thermal convection and a non-forced oxygen depleted stream of air exits said air flow-through passageway via thermal convection and/or an oxygen concentration gradient.

12. The fuel cell pack according to claim 10, wherein said air flow-through passageway is formed between said air contacting surfaces of two of said air electrodes.

13. The fuel cell pack according to claim 1, wherein each of said air electrodes are sealed in an air electrode frame exposing said air contacting surface and said electrolyte contacting surface of said air electrode.

14. The fuel cell pack according to claim 1, further comprising:

a hydrogen supply subsystem; and

a protective casing.

15. The fuel cell pack according to claim 14, wherein said hydrogen supply subsystem is in gaseous communication with said fuel cell stack, said hydrogen supply subsystem being adapted to receive a supply of hydrogen from at least one hydrogen storage container and distribute said supply of hydrogen to said fuel cell stack.

16. The fuel cell pack according to claim 15, wherein said hydrogen storage containers are adapted to store hydrogen in a liquid form, gaseous form, a chemical hydride form, and a metal hydride form.

17. The fuel cell pack according to claim 15, wherein said hydrogen storage containers are adapted to store hydrogen in a metal hydride form.

18. The fuel cell pack according to claim 17, wherein said hydrogen storage container is placed in thermal contact with a non-forced stream of heated air exiting the top of said fuel cell stack via convection to aid in desorption of hydrogen from said metal hydride.

19. The fuel cell pack according to claim 17, wherein said electrolyte circulating loop is adapted to provide heat to said hydrogen storage containers to aid in desorption of hydrogen from said metal hydride.

20. The fuel cell pack according to claim 14, wherein said protective casing has a plurality of openings through which air enters and exits said fuel cell pack via thermal convection and/or an oxygen concentration gradient.