System for purging non-fuel material from fuel cell anodes

• US 20090269634A1
• Filed: 01/29/2009
• Published: 10/29/2009
• Est. Priority Date: 01/29/2008
• Status: Abandoned Application

• Current Assignee: Ardica Technologies Incorporated
• Original Assignee: Ardica Technologies Incorporated
• Inventors: Fabian, Tibor, Braithwaite, Daniel, Fisher, Tobin J.
• Application Number:
  US12/322,337
• Publication Number:
  US 20090269634A1
• Time in Patent Office: Days
• US Class Current: 429/430
• CPC Class Codes: H01M 2250/30 Fuel cells in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 8/0273 with sealing or supporting means in the form of a frame
• CPC Class Codes: H01M 8/04067 Heat exchange or temperature measuring elements, thermal insulation, e.g. heat pipes, heat pumps, fins
• CPC Class Codes: H01M 8/04089 of gaseous reactants
• CPC Class Codes: H01M 8/04298 Processes for controlling fuel cells or fuel cell systems
• CPC Class Codes: H01M 8/1097 Fuel cells applied on a support, e.g. miniature fuel cells deposited on silica supports
• CPC Class Codes: H01M 8/2475 Enclosures, casings or containers of fuel cell stacks
• CPC Class Codes: Y02B 90/10 Applications of fuel cells in buildings
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A fuel cell gas purge system is provided that includes at least one fuel cell, such as a fuel cell stack or a fuel cell array, a fuel supply, and an adjustable fuel cell current load. The system further includes at least one passive purge valve disposed to purge accumulated non-fuel matter in the fuel cell, and operates according to a pressure differential across the valve. The valve can be a passive bi-directional valve, such as a dome valve, or a passive unidirectional valve. Further included is a purge management module that has a purge request module to determine when to increase the pressure of the hydrogen fuel to initiate the purge, and a purge complete module to determine when to adjust the pressure of the hydrogen fuel to complete the purge. The non-fuel matter can include non-fuel gases or condensed water.

Claims

1. A fuel cell purge system comprising:

a. at least one fuel cell;

b. a fuel supply;

c. an adjustable fuel cell current load;

d. at least one passive purge valve disposed to purge accumulated non-fuel matter in said fuel cell, wherein said passive purge valve operates according to a pressure differential across said passive purge valve; and

e. a purge management module, wherein said purge management module comprises a purge request module and a purge complete module, wherein said purge request module determines when to increase a pressure of said fuel to initiate said purge and said purge complete module determines when to decrease said pressure of said fuel to complete said purge.

2. The fuel cell purge system of claim 1, wherein said fuel cell is selected from the group consisting of hydrogen fuel cell, propane fuel cell, butane fuel cell and methane fuel cell.

3. The fuel cell purge system of claim 1, wherein said at least one fuel cell is selected from the group consisting of a single fuel cell, a fuel cell stack and a fuel cell array.

4. The fuel cell purge system of claim 1, wherein said non-fuel matter is selected from the group consisting of non-fuel gases and condensed water.

5. The fuel cell purge system of claim 1, wherein during normal operation said adjustable fuel cell load is adjusted to keep said pressure that is upstream of said passive purge valve below a cracking pressure of said passive purge valve, wherein during said purge said adjustable fuel cell load is adjusted to increase said pressure upstream of said passive purge valve above said cracking pressure.

6. The fuel cell purge system of claim 1, wherein said adjustable fuel cell load comprises a battery charger circuit attached to a battery, wherein a charging current of said battery can be adjusted.

7. The fuel cell purge system of claim 1, wherein said passive purge valve is selected from the group consisting of a passive bi-directional valve and a passive unidirectional valve.

8. The fuel cell purge system of claim 7, wherein said bi-directional valve comprises a dome valve.

9. The fuel cell purge system of claim 1, wherein a cracking pressure of said passive purge valve is as low as 1 PSI.

10. The fuel cell purge system of claim 1, wherein said passive purge valve is disposed at a distal end of at least two said fuel cells having said fuel connected in series, wherein a source of said fuel is disposed at a proximal end of said array.

11. The fuel cell purge system of claim 1, wherein said purge request module determines when said non-fuel matter needs to be purged by sensing when a voltage of any of said fuel cells drop below a predetermined threshold.

12. The fuel cell purge system of claim 11, wherein said purge request module determines when said non-fuel matter needs to be purged by sensing when a voltage in said fuel cell that is most proximal to said passive purge valve drops below a predetermined threshold.

13. The fuel cell purge system of claim 1, wherein said purge complete module determines when said non-fuel material has been purged from at least one said fuel cell by sensing when said purge comprises primarily said fuel.

14. The fuel cell purge system of claim 1, wherein said purged non-fuel matter from said passive purge valve is directed across a cathode of one said fuel cell in an array of said fuel cells, wherein said purge complete module determines when said non-fuel matter has been purged by sensing when a voltage of said upstream fuel cell drops below a threshold voltage.

15. The fuel cell purge system of claim 1, wherein said purged non-fuel matter from said passive purge valve is directed to a catalyst bed in the presence of ambient air, wherein said purge complete module determines when said non-fuel matter has been purged by sensing when a temperature of said catalyst bed exceeds a threshold level.

16. The fuel cell purge system of claim 15, wherein said catalyst is selected from the group consisting of Platinum, Palladium, Ruthenium, Manganese oxide, Silver oxide and Cobalt oxide.

17. The fuel cell purge system of claim 1, wherein said purge complete module determines when said non-fuel material has been purged by using a timer.

18. The fuel cell purge system of claim 17, wherein a duration of said timer is determined according to a current load in one said fuel cell before said purge was initiated.

19. The fuel cell purge system of claim 1, wherein said purged non-fuel matter from said passive purge valve is directed to the anode of an auxiliary fuel cell, wherein said purge complete module determines when said non-fuel matter has been purged by sensing when an output of said fuel cell exceeds a threshold level, wherein said output comprises a current or a voltage.