Air cooled fuel cell module

• US 20040214057A1
• Filed: 04/28/2003
• Published: 10/28/2004
• Est. Priority Date: 04/28/2003
• Status: Active Grant

• Current Assignee: Emergent Power Inc. (Plug Power Inc.)
• Original Assignee: Relion Incorporated (Plug Power Inc.)
• Inventors: Fuglevand, William A., Wright, Matthew M., Bayyuk, Shibli Hanna I., Lloyd, Greg A., Wilkerson, Shalena V.
• Granted Patent: US 6,939,636 B2
• Time in Patent Office: Days
• US Class Current: 429/20
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 8/0232 Metals or alloys
• CPC Class Codes: H01M 8/0245 in the form of layered or coated products
• CPC Class Codes: H01M 8/0247 characterised by the form characterised by a channel configuration H01M8/0258
• CPC Class Codes: H01M 8/0254 corrugated or undulated
• CPC Class Codes: H01M 8/0267 having heating or cooling means, e.g. heaters or coolant flow channels
• CPC Class Codes: H01M 8/04014 Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
• 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 8/04291 Arrangements for managing water in solid electrolyte fuel cell systems H01M8/04119 takes precedence
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/241 with solid or matrix-supported electrolytes
• CPC Class Codes: H01M 8/2418 Grouping by arranging unit cells in a plane H01M8/2425, H01M8/244 take precedence
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An air cooled fuel cell module is described and which includes an ion exchange membrane having opposite anode and cathode sides; an electrode borne by each of the anode and cathode sides; and a cathode heat sink positioned in heat removing relation relative to the cathode side of the ion exchange membrane, and which, in one form of the invention, can simultaneously act as a current collector.

Claims

1. An air cooled fuel cell module, comprising:

an ion exchange membrane having opposite anode and cathode sides;

an electrode borne by each of the anode and cathode sides; and

a cathode heat sink positioned in heat removing relation relative to the cathode side of the ion exchange membrane.

2. An air cooled fuel cell module as claimed in claim 1, and wherein the cathode heat sink simultaneously acts as a cathode current collector.

3. An air cooled fuel cell module as claimed in claim 1, and further comprising:

a current collector disposed in ohmic electrical contact with each of the anode and cathode sides, and wherein the cathode heat sink is positioned between cathode side of the ion exchange membrane and the cathode current collector.

4. An air cooled fuel cell module as claimed in claim 1, and further comprising:

a current collector disposed in ohmic electrical contact with each of the anode and cathode sides, and wherein the cathode current collector is positioned between the ion exchange membrane and the cathode heat sink.

5. An air cooled fuel cell module as claimed in claim 2, and wherein the cathode heat sink acts simultaneously as a cathode current collector, and wherein the cathode heat sink is fabricated from an air-permeable metal foam having an open-celled microstructure.

6. An air cooled fuel cell module as claimed in claim 2, and wherein the cathode heat sink acts simultaneously as a cathode current collector, and wherein the cathode heat sink is fabricated from a metal substrate which defines a plurality of channels which are oriented in substantially the same direction, and which extend across the cathode heat sink.

7. An air cooled fuel cell module as claimed in claim 6, and wherein the metal substrate forming the cathode heat sink is corrugated.

8. An air cooled fuel cell module as claimed in claim 6, and wherein the metal substrate forming the cathode heat sink includes a plurality of vanes which define the respective channels.

9. An air cooled fuel cell module as claimed in claim 1, and wherein the cathode heat sink acts simultaneously as a cathode current collector, and wherein water and heat energy are produced as a byproduct of fuel cell module operation, and wherein the cathode heat sink facilitates the transmission of heat energy which is generated during fuel cell module operation away from the ion exchange membrane at a rate which does not cause either excessive evaporation of water from the ion exchange membrane, or excessive retention of water by the ion exchange membrane.

10. An air cooled fuel cell module as claimed in claim 1, and further comprising:

a cathode air flow which has a flow rate, and which passes over the cathode heat sink, and which further is supplied, in part, to the cathode side of the ion exchange membrane, and wherein water and heat energy are produced as byproducts of fuel cell module operation, and wherein the cathode air flow is supplied at a flow rate which facilitates the removal of a portion of the heat energy transmitted away from the ion exchange membrane by way of the cathode heat sink, while simultaneously supplying a cathode air flow in an amount which, while supporting fuel cell module operation, does not simultaneously cause evaporation of water from the ion exchange membrane in an amount which would substantially impede fuel cell module operation.

11. An air cooled fuel cell module, comprising:

an ion exchange membrane having opposite anode and cathode sides;

an electrode borne by each of the anode and cathode sides; and

a current collector disposed in ohmic electrical contact with each of the anode and cathode sides, and wherein at least one of the current collectors is fabricated from an air-permeable metal foam having an open-celled microstructure, and which further acts as a heat sink to remove heat energy generated by the fuel cell module during operation.

12. An air cooled fuel cell module as claimed in claim 11, and further comprising an ambient air flow which is provided to the air cooled fuel cell module to at least, in part, dissipate heat energy generated during fuel cell module operation, and wherein the open-celled microstructure has a plurality of pores which are oriented in a fashion to facilitate the passage of the ambient air stream therethrough while simultaneously facilitating the removal of the heat energy from the fuel cell module and the dissipation of the heat energy to the ambient air flow.

13. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector has a plurality of pores which have an average dimension of about 80 micrometers to about 8 millimeters.

14. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector has a plurality of pores having an average pore size of about 3 to about 300 pores per inch.

15. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector has a porosity of about 50% to about 98.5%.

16. An air cooled fuel cell module as claimed in claim 11, and wherein the fuel cell module, during operation, generates both heat energy, and water as byproducts, and wherein the water hydrates, at least in part, the ion exchange membrane, and wherein the air-permeable metal foam current collector, acting as a heat sink, dissipates, at least in part, the heat energy generated during fuel cell module operation and further simultaneously facilitates the operable hydration of the ion exchange membrane.

17. An air cooled fuel cell module as claimed in claim 11, and wherein a gas diffusion layer is borne on one of the anode or cathode sides of the ion exchange membrane, and wherein the air-permeable metal foam current collector exerts force on the gas diffusion layer borne on one of the anode and/or cathode sides of the ion exchange membrane to minimize an ohmic electrical resistance which exists between the air-permeable metal foam current collector and the adjacent gas diffusion layer.

18. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector is fabricated, in whole, or in part, from a material which is selected from a group comprising aluminum;

copper;

a transition metal, or an alloy thereof.

19. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector has a thermal conductivity of about 1.0 W/M-K to about 117 W/M-K at a temperature of 25 degrees C.

20. An air cooled fuel cell module as claimed in claim 11, and wherein at least one electrically conductive gas diffusion layer is borne by one of the electrodes, and wherein the air-permeable metal foam current collector lies in ohmic electrical contact thereagainst the electrically conductive gas diffusion layer.

21. An air cooled fuel cell module as claimed in claim 11, and wherein at least one electrically conductive gas diffusion layer having a variable porosity and hydrophobicity is borne by one of the electrodes, and wherein the air-permeable metal foam current collector lies in ohmic electrical contact thereagainst the electrically conductive gas diffusion layer.

22. An air cooled fuel cell module as claimed in claim 11, and wherein at least one electrically conductive gas diffusion layer having an outwardly facing surface is borne by one of the electrodes, and wherein a porous metal coating is borne by the outwardly facing surface, and wherein the air-permeable metal foam current collector lies in ohmic electrical contact thereagainst the porous metal coating, and wherein a substantially pressure independent contact resistance is established between the porous metal coating and the adjacent air-permeable metal foam current collector.

23. An air cooled fuel cell module as claimed in claim 11, and wherein the fuel cell module, during operation, generates heat energy, and wherein the air cooled fuel cell module has a cathode air flow which passes, at least in part, through the air-permeable metal foam current collector, and wherein the cathode air flow removes a preponderance of the heat energy generated during operation of the air cooled fuel cell module.

24. An air cooled fuel cell module as claimed in claim 11, and wherein the air-cooled fuel cell module, during operation, generates heat energy, and wherein the air-permeable metal foam current collector is disposed in ohmic electrical contact with the cathode side of ion exchange membrane, and wherein the air cooled fuel cell module has an air flow having a component which passes, at least in part, through the air-permeable metal foam current collector, and wherein the component of the air flow passing through the current collector dissipates less than a preponderance of the heat energy generated during operation of the air cooled fuel cell module.

25. An air cooled fuel cell module as claimed in claim 24, and wherein the air cooled fuel cell module includes an anode heat sink which is disposed in heat removing relation relative to the anode side of the ion exchange membrane, and wherein the air flow provided to the fuel cell module has a second component which passes, at least in part, over the anode heat sink, and wherein the second component of the air flow dissipates a preponderance of the heat energy generated during operation of the fuel cell to ambient.

26. An air cooled fuel cell module as claimed in claim 25, and wherein the anode heat sink is fabricated from an air-permeable metal foam.

27. An air cooled fuel cell module as claimed in claim 11, and wherein an electrically conductive gas diffusion layer is borne on one of the anode and cathode sides, and wherein a contact resistance is created between the air-permeable metal foam current collector, and the electrically conductive gas diffusion layer, and wherein the air-permeable metal foam current collector exerts a force on the underlying electrically conductive gas diffusion layer to minimize the contact resistance.

28. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector is fabricated from a metal or metal alloy which has an electrical resistivity of about 1.65 microohms-centimeter to about 15 microohms-centimeter at 25 degrees C.

29. An air cooled fuel cell module as claimed in claim 11, and wherein the air cooled fuel cell module has a cathode air flow which controls, at least in part, the operating temperature of the air cooled fuel cell module, and wherein the air cooled fuel cell module, during operation, generates heat energy, and water which operably hydrates the ion exchange membrane, and wherein the air-permeable metal foam current collector substantially minimizes evaporative water loss from the ion exchange membrane.

30. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector is fabricated from a metal or a metal alloy which has a thermal conductivity value of about 218 W/M-K at a temperature of 25 degrees C.

31. An air cooled fuel cell module as claimed in claim 11, and wherein the air-permeable metal foam current collector has a porosity which is greater than about 50%.

32. A fuel cell module, comprising:

an ion exchange membrane having opposite anode and cathode sides;

an electrode borne on each of the anode and cathode sides;

an electrically conductive gas diffusion layer borne by one of the electrodes;

a cathode air flow supplied to the cathode side of the ion exchange membrane; and

an air-permeable metal foam current collector disposed in ohmic electrical contact with the cathode side of the ion exchange membrane, and wherein the fuel cell module generates heat energy during operation, and wherein the air-permeable metal foam current collector has a thermal conductivity value which facilitates both the efficient transmission of the heat energy generated during fuel cell module operation away from the ion exchange membrane and to the cathode air flow, and the operational hydration of the ion exchange membrane.

33. A fuel cell module as claimed in claim 32, and wherein the cathode air flow passes at least in part through the air-permeable metal foam current collector.

34. A fuel cell module as claimed in claim 32, and wherein the air-permeable metal foam current collector is fabricated from a metal or metal alloy which has a thermal conductivity value of about 1.0 W/M-K to about 117 W/M-K at a temperature of 25 degrees C.

35. A fuel cell module as claimed in claim 32, and wherein the air-permeable metal foam current collector has a porosity of greater than about 72%.

36. A fuel cell module as claimed in claim 32, and wherein the air-permeable metal foam current collector has a plurality of pores each having an average dimension of about 80 micrometers to about 8 millimeters.

37. A fuel cell module as claimed in claim 32, and wherein water is produced as a byproduct of fuel cell module operation and which is utilized to hydrate the ion exchange membrane, and wherein the air-permeable metal foam current collector has a selected thermal conductivity value which facilitates the transmission of heat energy generated during fuel cell module operation away from the ion exchange membrane at a rate which does not cause either, excessive evaporation of water from the ion exchange membrane, or excessive retention of water by the ion exchange membrane.

38. A fuel cell module as claimed in claim 37, and wherein the cathode air flow has a flow rate which facilitates the removal of a portion of the heat energy transmitted away from the ion exchange membrane by way of the air-permeable metal foam current collector, while simultaneous supplying a cathode air flow in an amount which, while supporting fuel cell module operation, does not simultaneously cause evaporation of water from the ion exchange membrane in an amount which would substantially impede fuel cell module operation.

39. A fuel cell module comprising:

an ion exchange membrane having opposite anode and cathode sides;

an electrode borne on each of the anode and cathode sides, and wherein the fuel cell, during operation, generates heat energy and water as byproducts, and wherein the water produced as a byproduct operably hydrates, at least in part, the ion exchange membrane;

an electrically conductive gas diffusion layer borne on one of the anode and/or cathode sides and which is disposed in at least partial covering relation relative to the electrode;

a cathode air flow having a flow rate, and which is supplied to the cathode side of the ion exchange membrane; and

an air-permeable metal foam current collector disposed in ohmic electrical contact with the cathode side of the ion exchange membrane, and which has a porosity and a thermal conductivity value, and wherein the porosity and thermal conductivity values of the air permeable metal foam current collector are selected so as to permit the cathode air flow which passes through air-permeable metal foam to have a reduced flow rate while simultaneously providing an adequate amount of air to support fuel cell module operation, and while simultaneously facilitating the dissipation of at least a portion of the heat energy generated during fuel cell module operation, and wherein the cathode air flow rate further does not cause either, evaporation of excessive amounts of water from the ion exchange membrane, or retention of water by the ion exchange membrane in an excessive amount which would substantially impede fuel cell module operation.

40. A fuel cell module as claimed in claim 39, and wherein the air-permeable metal foam current collector has at least about 3 pores/inch.

41. A fuel cell module as claimed in claim 40, and wherein the pores of the air permeable metal foam current collector have an average dimension of at least about 80 micrometers to about 8 millimeters.

42. A fuel cell module as claimed in claim 39, and wherein the air-permeable metal foam current collector has a porosity of at least about 72%.

43. A fuel cell module as claimed in claim 39, and wherein the air-permeable metal foam current collector is fabricated of a metal or metal alloy which has a thermal conductivity value of greater than 50 W/M-K at a temperature of 25 degrees C.

44. A fuel cell as claimed in claim 43, and wherein the air-permeable metal foam current collector has an outwardly facing surface which rests in ohmic electrical contact thereagainst the cathode side of the ion exchange membrane, and wherein the air-permeable metal foam current collector is fabricated from a metal or metal alloy which has an electrical resistivity of at least about 1.65 microohms-centimeter to about 15 microohms-centimeter at a temperature of 25 degrees C.

45. A fuel cell module as claimed in claim 39, and wherein the fuel cell module is substantially self-hydrating, and air cooled.

46. A fuel cell module as claimed in claim 39, and wherein the cathode air flow provided to the fuel cell module dissipates a preponderance of the heat energy generated during fuel cell module operation to ambient.

47. A fuel cell module as claimed in claim 39, and wherein the cathode air flow provided to the fuel cell module dissipates less than a preponderance of the heat energy generated during fuel cell module operation to ambient.

48. A fuel cell module as claimed in claim 39, and wherein the air-permeable metal foam current collector has an outwardly facing surface, and wherein a contact resistance is established between the outwardly facing surface and the adjacent electrically conductive gas diffusion layer, and wherein the air-permeable metal foam current collector exerts a force on the ion exchange membrane which substantially minimizes the contact resistance.

49. A fuel cell module as claimed in claim 48, and wherein the air-permeable metal foam current collector exerts a pressure of at least about 10 to about 280 PSI.

50. A fuel cell module as claimed in claim 39, and further comprising:

a porous metal layer borne by the electrically conductive gas diffusion layer, and wherein a substantially pressure independent contact resistance is established between the air-permeable metal foam current collector and the porous metal layer.

51. A fuel cell as claimed in claim 39, and wherein the gas diffusion layer has a variable porosity and hydrophobicity.