Direct methanol feed fuel cell and system

• US 7,470,478 B2
• Filed: 03/09/2004
• Issued: 12/30/2008
• Est. Priority Date: 10/12/1993
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Kindler, Andrew, Narayanan, Sekharipuram R., Frank, Harvey A., Surampudi, Subbarao, Chun, William, Halpert, Gerald, Jeffries-Nakamura, Barbara
• Primary Examiner(s): Kalafut; Stephen J.
• Application Number:
  US10/797,625
• Publication Number:
  US 20050003254A1
• Time in Patent Office: 1,757 Days
• Field of Search: 429/12, 429/13, 429/14, 429/16, 429/30, 429/33, 429/42, 429/17
• US Class Current: 429/410
• CPC Class Codes: H01M 2300/0082 Organic polymers
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8663 Selection of inactive substances as ingredients for catalytic active masses, e.g. binders, fillers
• CPC Class Codes: H01M 4/921 Alloys or mixtures with metallic elements
• CPC Class Codes: H01M 8/0202 Collectors; Separators, e.g. bipolar separators; Interconnectors
• CPC Class Codes: H01M 8/0228 in the form of layered or coated products
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/0247 characterised by the form characterised by a channel configuration H01M8/0258
• CPC Class Codes: H01M 8/04156 with product water removal
• CPC Class Codes: H01M 8/04186 of liquid-charged or electrolyte-charged reactants
• CPC Class Codes: H01M 8/04194 Concentration measuring cells
• CPC Class Codes: H01M 8/04201 Reactant storage and supply, e.g. means for feeding, pipes
• CPC Class Codes: H01M 8/0687 Reactant purification by the use of membranes or filters
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1009 with one of the reactants being liquid, solid or liquid-charged H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1011 Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
• CPC Class Codes: H01M 8/1018 Polymeric electrolyte materials
• 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: H01M 8/2455 with liquid, solid or electrolyte-charged reactants
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Improvements to non acid methanol fuel cells include new formulations for materials. The platinum and ruthenium are more exactly mixed together. Different materials are substituted for these materials. The backing material for the fuel cell electrode is specially treated to improve its characteristics. A special sputtered electrode is formed which is extremely porous.

Claims

1. A fuel cell system, comprising:

a fuel cell stack comprising an anode, a cathode, and a solid polymer electrolyte membrane between said anode and cathode, said anode and cathode being each in contact with fluid, wherein the fluid in contact with said anode includes a methanol fuel which is substantially free of acid electrolyte liquid; and

a turbine, driven by pressure of one of an output fluid from said cathode that includes both liquid and gas, and recycling pressure.

2. A fuel cell system as in claim 1, wherein said anode is in contact with pressurized gas, and said turbine is driven by said pressurized gas.

3. A fuel cell system as in claim 1, further comprising an air compressor, driven by said turbine, and recycling pressure, driving said turbine.

4. A fuel cell system as in claim 1, wherein said polymer electrolyte membrane is a proton conducting, solid polymer electrolyte membrane.

5. A fuel cell system as in claim 1, wherein said anode includes an electrochemical catalyst thereon.

6. A liquid feed direct oxidation organic fuel cell, comprising:

a fuel cell stack formed of an anode, including an electrochemical catalyst thereon, a proton conducting solid polymer electrolyte membrane, coupled to said anode, and a cathode, coupled to another side of said proton conducting solid polymer electrolyte membrane, said fuel cell stack capable of oxidizing liquid methanol without free soluble acid or base electrolytes; and

a pressure recycling device, operating to recycle pressure from a liquid and gas combination which is in contact with said fuel cell stack.

7. A fuel cell as in claim 6, wherein said pressure recycling device includes a turbine.

8. A fuel cell as in claim 6, wherein said pressure recycling device includes an expander.

9. A fuel cell as in claim 6, wherein said pressure recycling device is coupled to gases in contact with said anode.

10. A fuel cell as in claim 9, further comprising a water/air separator, also coupled to gases in contact with said anode, operating to separate air from water.

11. A fuel cell as in claim 10, further comprising a water recycling part, which feeds back water from the water/air separator to be reused in subsequent reactions.

12. A fuel cell as in claim 11, further comprising a vent, allowing excess water to be removed.

13. A fuel cell as in claim 6, further comprising a water recycling part, operating to recycle water from a cathode back to an anode.

14. A fuel cell as in claim 13, further comprising a vent for excess water.

15. A fuel cell as in claim 14, further comprising a controller, which monitors an amount of water in the system, and controls said vent for excess water to remove water when too much water is being recirculated.

16. A fuel cell as in claim 6, further comprising at least one fan, driven by said pressure recycling device.

17. A fuel cell as in claim 16, further comprising at least one pump, operating to pump methanol.

18. A fuel cell system, comprising:

a fuel cell stack, including an anode, a cathode, and a proton conducting solid polymer membrane, connected between said anode and cathode, and connected thereto, wherein said anode is formed with an electrochemical catalyst, and a proton conducting material therein, and also being electrically conducting, and said cathode formed of a gas diffusion material which allows diffusion of gas;

a fluid feed system including a liquid methanol source, in contact with said fuel cell stack, and providing methanol to said fuel cell stack, which methanol is substantially free of any free acid electrolytes therein, and a gas source, providing gas to said cathode for an electrochemical reaction; and

a pressure device, coupled to receive a mix of liquid-gas material from said cathode, and to use pressure from said fluid in said fluid feed system in another system.

19. A system as in claim 18, wherein said pressure device includes a turbine driven from pressure from said fluid feed system.

20. A system as in claim 19, wherein said turbine is coupled to said gas source part of said fluid feed system.

21. A system as in claim 18, wherein said pressure device is coupled to said gas source part of said fluid feed system.

22. A system as in claim 18, further comprising a gas/liquid separator, coupled to said gas source part of said fluid feed system.

23. A system as in claim 22, further comprising a water recycling part, feeding back liquid from said gas/liquid separator.

24. A system as in claim 18, further comprising a pressure driven device, driven to receive its pressure from said pressure device.

25. A system as in claim 24, wherein said pressure driven device includes a fan.

43. A system as in claim 18, wherein said pressure device includes a gas/liquid separator, separating liquid from gas in the material received from said cathode, and recycling pressure based on gas in the mixture.

26. A method, comprising:

operating a fuel cell which operates with a liquid, organic alcohol containing fuel;

receiving an output that includes both liquid and gas and

using a pressure from said output to drive a pressure-driven device.

27. A method as in claim 26, wherein said using comprises using said pressure to drive another portion of the fuel cell.

28. A method as in claim 26, wherein said one portion of the fuel cell is in contact with fluid used within the fuel cell.

29. A method as in claim 28, wherein said one portion of the fuel cell is in contact with a gas supply to the cathode.

30. A method as in claim 27, wherein said another portion of the fuel cell includes a fan driven by recycled pressure.

31. A method as in claim 26, further comprising using the pressure to carry out another operation in the fuel cell.

32. A method as in claim 26, wherein said operating comprises carrying out an electrochemical reaction on the methanol fuel cell using a methanol fuel which is substantially free of free acid electrolytes.

44. A method as in claim 26 wherein said using a pressure comprises separating liquid from gas, and recycling pressure from the separated materials.

33. A method, comprising:

supplying fluids to a direct fed methanol fuel cell stack, which fluids include at least one liquid which includes an anode, a cathode, and a proton conducting solid polymer electrolyte membrane between said anode and cathode;

carrying out an electrochemical reaction using fluids; and

receiving an output from said electrochemical reaction that includes both liquids and gas recovering pressure from the output.

34. A method as in claim 33, wherein said recovering pressure comprises using pressure from said fluids to carry out another operation in said fuel cell.

35. A method as in claim 34, wherein said recovering pressure comprises using pressure from said fluids to drive a fan.

36. A method as in claim 33, further comprising recovering fluids after the electrochemical reaction has been carried out, so that at least part of the fluids after the electrochemical reaction are fed back for a subsequent electrochemical reaction.

37. A method as in claim 33, wherein said recovering pressure comprises using the pressure to drive a turbine.

45. A method as in claim 33, wherein said recovering pressure comprises separating liquids from said gas in said output, and recycling pressure from the separated materials.

38. A fuel cell system, comprising:

a fuel cell stack, including an anode, a cathode, and a proton conducting solid polymer membrane, connected between said anode and cathode, and connected thereto, wherein said anode is formed with an electrochemical catalyst, and a proton conducting material therein, and also electrically conducting, and said cathode is formed of a gas diffusion material which allows diffusion of gas therein;

a liquid feed system including a liquid methanol source, in contact with said fuel cell stack, and providing liquid methanol to said fuel cell stack, which methanol is substantially free of any free acid electrolytes therein, and a gas source, providing gas to said cathode for an electrochemical reaction; and

a fluid recycling device, coupled to receive a mixed gas-liquid material after reaction with the cathode, and recycling a pressure of said fluid, and a part of said fluid back to the anode.

39. A fuel cell system as in claim 38, further comprising a liquid/gas separator, separating liquid parts of the recycled fuel from gas parts of the recycled fuel.

40. A fuel cell system as in claim 39, wherein said liquid parts of the recycled fuel are fed back to the anode.

41. A fuel cell system as in claim 38, further comprising a valve, which vents excess water if too much water has been recycled.

42. A fuel cell system as in claim 38, further comprising a pressure recycling system, in contact with said fluid feed system, and operating to recycle pressure within the fluid feed system by receiving pressure therefrom, and providing recycling pressure to carry out another operation in the fuel cell.

46. A system as in claim 38, wherein said fluid recycling device includes a liquid/gas separator, separating liquid from gas, and recovering pressure from the separated materials.