Direct methanol feed fuel cell and system

• US 7,488,548 B2
• Filed: 08/30/2004
• Issued: 02/10/2009
• Est. Priority Date: 10/12/1993
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Narayanan, Sekharipuram R., Frank, Harvey A., Surampudi, Subbarao, Chun, William, Halpert, Gerald, Jeffries-Nakamura, Barbara, Kindler, Andrew
• Primary Examiner(s): Kalafut; Stephen J.
• Application Number:
  US10/930,505
• Publication Number:
  US 20050042487A1
• Time in Patent Office: 1,625 Days
• Field of Search: 429/13, 429/15, 429/22, 429/24, 429/30, 429/34
• 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. The fuel cell system also comprises a fuel supplying part including a meter which meters an amount of fuel which is used by the fuel cell, and controls the supply of fuel based on said metering.

Claims

1. A direct fed methanol system, comprising:

a fuel cell stack, including an anode, a cathode, and a proton conducting solid polymer electrolyte membrane coupled between said anode and cathode; and

a fuel supplying part, which supplies methanol containing fuel which is substantially free of free acid electrolyte to said anode of said fuel cell stack including a meter which meters an amount of fuel which is used by the fuel cell, and controls supply of fuel based on said metering.

2. A system as in claim 1, further comprising a temperature correction device for the fuel supplying part which controls a supplying based on at least partly a temperature correction.

12. A system as in claim 1, wherein said controlling part is an electrical controlling part, and power for the controlling part is provided from said fuel cells stack.

3. A direct fed methanol system, comprising:

a fuel cell stack, including an anode, a cathode, and a proton conducting solid polymer electrolyte membrane coupled between said anode and cathode; and

a fuel supplying part, which supplies methanol containing fuel which is substantially free of free acid electrolyte to said anode of said fuel cell stack, said fuel supplying part including a controlling part which controls an amount of fuel which is supplied and which includes a sensor which senses an amount of use of methanol fuel, and which controls supplying additional methanol fuel based on the sensing.

4. A system as in claim 3, wherein the sensor Includes an electronic sensor.

5. A system as in claim 4, further comprising a temperature sensor, which corrects an output of the electronic sensor.

6. A system as in claim 4, wherein said electronic sensor produces an electrical output, which is indicative of a methanol concentration.

7. A system as in claim 6, further comprising a temperature sensor, which produces information for correcting an output of the electronic sensor.

8. A system as in claim 7, wherein said temperature sensor includes a thermocouple.

9. A system as in claim 6, further comprising a controller which determines methanol concentration based on said electrical output.

10. A system as in claim 9, further comprising a temperature sensor, which produces temperature correction output for the electrical outlet, and wherein said controller uses said temperature correction information to determine methanol concentration for a specific temperature.

11. A system as in claim 10, wherein said controller controls a methanol concentration based on the determined methanol concentration.

13. A system as in claim 4, wherein power to operate said electronic sensor is provided from said fuel cell stack.

14. A method, comprising:

Supplying methanol fuel to a fuel cell stack of the direct fed methanol type;

carrying out an electrochemical reaction using said methanol fuel; and

metering an amount of fuel which is supplied to the fuel cell, wherein said metering comprises electrically metering the fuel, and wherein said electrochemical reaction comprises producing power using the electrochemical reaction and using said power to operate said electrically metering.