Claims
- 1. A fuel reservoir for a liquid fuel cell, comprising:
(a) a container having a wall and an interior defining a cavity holding a liquid fuel for the liquid fuel cell; (b) a wicking structure disposed within the cavity and into which at least a portion of the liquid fuel wicks and from which the liquid fuel may subsequently be delivered, wherein substantially all of the free liquid fuel in the container is contactable by the wicking structure, wherein the wicking structure has a longest dimension and the free rise wick height of the wicking structure is greater than at least one half of the longest dimension; and (c) an outlet that provides fluid communication of the wicking structure through the wall of the container to a location exterior of the container, wherein the fuel reservoir is selectively detachable from or attachable to a liquid fuel cell.
- 2. The fuel reservoir of claim 1, wherein the free rise wick height of the wicking structure is greater than the longest dimension.
- 3. The fuel reservoir of claim 2, wherein the wicking structure comprises a wicking material selected from the group consisting of foams, bundled fibers, matted fibers, woven fibers, nonwoven fibers and inorganic porous materials.
- 4. The fuel reservoir of claim 1, wherein the wicking structure comprises a wicking material selected from the group consisting of foams, bundled fibers, matted fibers, woven fibers and nonwoven fibers.
- 5. The fuel reservoir of claim 4, wherein the wicking material is selected from the group consisting of polyurethane foam, melamine foam, cellulose foam, nonwoven felts of polyamide, polyethylene, polypropylene, polyester, polyacrylonitrile, or mixtures thereof, bundled, matted or woven fibers of cellulose, polyester, polyethylene, polypropylene and polyacrylonitrile, or mixtures thereof.
- 6. The fuel reservoir of claim 5, wherein the polyurethane foam is a felted polyurethane foam, reticulated polyurethane foam or felted reticulated polyurethane foam, the polyamide is nylon and the polyester is polyethylene terephthalate.
- 7. The fuel reservoir of claim 6, wherein the wicking material is selected from the group consisting of a felted polyurethane foam, reticulated polyurethane foam and felted reticulated polyurethane foam.
- 8. The fuel reservoir of claim 4, wherein the wicking structure comprises a polyurethane foam with a density in the range of about 0.5 to about 45 pounds per cubic foot and pore sizes in the range of about 10 to about 200 pores per linear inch.
- 9. The fuel reservoir of claim 8, wherein the wicking structure comprises a polyurethane foam with a density in the range of 0.5 to 15 pounds per cubic foot and pore sizes in the range of 40 to 200 pores per linear inch.
- 10. The fuel reservoir of claim 4, wherein the wicking structure is a felted reticulated polyurethane foam with a density in the range of 2 to 45 pounds per cubic foot and a compression ratio in the range of 1.1 to 30.
- 11. The fuel reservoir of claim 1, wherein the wicking structure has a capillarity gradient.
- 12. The fuel reservoir of claim 11, wherein the wicking structure comprises two or more components, wherein at least two of such components have different capillarities.
- 13. The fuel reservoir of claim 11, wherein the wicking structure comprises a foam felted to varying degrees of compression along a length of the foam.
- 14. The fuel reservoir of claim 11, wherein the capillarity is greatest at a portion of the wicking structure proximate the outlet, and a distal portion of the wicking structure is of lesser capillarity.
- 15. The fuel reservoir of claim 1, further comprising:
a liquid delivery means in fluid communication with the outlet to deliver the liquid fuel out of the container through the outlet to the location exterior of the container.
- 16. A combination comprising the fuel reservoir of claim 15 and an anode of a liquid fuel cell, wherein the liquid delivery means is in fluid communication with the anode.
- 17. The combination of claim 16, wherein the liquid delivery means is a wick, said wick delivering the liquid fuel to the anode.
- 18. The combination of claim 16, wherein the liquid delivery means is a wick, said wick being in contact with a wicking link in fluid communication with the anode, said wicking link comprising at least a second wick, wherein said wick and said wicking link form a capillarity gradient that directs the liquid fuel to flow from the outlet to the anode.
- 19. The fuel reservoir of claim 1, further comprising:
an air inlet through the container, said air inlet having a one-way valve to permit gas flow into the cavity of the container.
- 20. The fuel reservoir of claim 1, wherein the container has flexible sidewalls.
- 21. The fuel reservoir of claim 20, wherein the container comprises an envelope formed from one or more sheets of a plastic film or a plastic-coated film.
- 22. The fuel reservoir of claim 21, further comprising a removable tape that covers the outlet passageway when the container is shipped or stored prior to use.
- 23. The fuel reservoir of claim 21, wherein the container is flexibly bendable.
- 24. The fuel reservoir of claim 21, wherein the envelope has a first face and a second face and said first and second faces are substantially planar.
- 25. The fuel reservoir of claim 21, wherein the envelope is a pouch formed by heat-sealing or ultra-sonic welding.
- 26. The fuel reservoir of claim 1 which is recyclable, wherein the outlet has a valve that allows liquid fuel to be introduced into the cavity.
- 27. The fuel reservoir of claim 1 which is recyclable, wherein the outlet has a sealable cap that allows liquid fuel to be introduced into the cavity.
- 28. The fuel reservoir of claim 27, wherein the sealable cap has a membrane that upon puncture allows the introduction of the liquid fuel into the cavity, and after liquid fuel introduction the membrane reseals the cavity.
- 29. The fuel reservoir of claim 28, wherein the membrane comprises rubber.
- 30. The fuel reservoir of claim 12, wherein the wicking structure comprises first and second components, said first component having a higher capillarity than the second component, wherein said first component has a longest dimension, and the free rise wick height of the first component is greater than one half of the longest dimension of said first component.
- 31. The fuel reservoir of claim 52, wherein the free rise wick height of the first component is greater than the longest dimension of said first component.
- 32. The fuel reservoir of claim 1, wherein the wicking structure is made of a permanently compressed wicking material.
- 33. The fuel reservoir of claim 1, wherein the wicking structure is made of a reversibly compressed wicking material.
- 34. The fuel reservoir of claim 1, wherein the wicking structure has a wicking structure volume and the wicking structure volume is no more than about 50% of a volume of the cavity.
- 35. The fuel reservoir of claim 34, wherein the wicking structure volume is no more than about 25% of the volume of the cavity.
- 36. The fuel reservoir of claim 35, wherein the wicking structure volume is no more than about 10% of the volume of the cavity.
- 37. The fuel reservoir of claim 1, wherein the wicking structure has an external volume and the void volume of the wicking structure is at least about 50% of the external volume of the wicking structure.
- 38. The fuel reservoir of claim 37, wherein the void volume of the wicking structure is about 65% to about 98% of the external volume of the wicking structure.
- 39. The fuel reservoir of claim 38, wherein the void volume of the wicking structure is about 70% to about 85% of the external volume of the wicking structure.
- 40. The fuel reservoir of claim 39, wherein the void volume of the wicking structure is about 75% of the external volume of the wicking structure.
- 41. The fuel reservoir of claim 40, wherein the void volume of the wicking structure is about 80% of the external volume of the wicking structure.
- 42. The fuel reservoir of claim 41, wherein the void volume of the wicking structure is about 85% of the external volume of the wicking structure.
- 43. The fuel reservoir of claim 1, wherein the liquid fuel comprises methanol.
- 44. The fuel reservoir of claim 1, wherein the liquid fuel is pure methanol.
- 45. The fuel reservoir of claim 1, wherein the liquid fuel is an aqueous mixture of methanol.
- 46. The fuel reservoir of claim 45, wherein the methanol concentration of the aqueous mixture is at least 25% by weight.
- 47. The fuel reservoir of claim 46, wherein the methanol concentration of the aqueous mixture is at least 50% by weight.
- 48. The fuel reservoir of claim 47, wherein the methanol concentration of the aqueous mixture is about 70% to 99% by weight.
- 49. The fuel reservoir of claim 48, wherein the methanol concentration of the aqueous mixture is about 90% by weight.
- 50. The fuel reservoir of claim 49, wherein the methanol concentration of the aqueous mixture is about 95% by weight.
- 51. The fuel reservoir of claim 50, wherein the methanol concentration of the aqueous mixture is about 99% by weight.
- 52. The fuel reservoir of claim 15, wherein the liquid delivery means is a pump or a wick having greater capillarity than the wicking structure.
- 53. The fuel reservoir of claim 52, wherein the liquid delivery means is the pump.
- 54. The fuel reservoir of claim 52, wherein the liquid delivery means is the wick.
- 55. The combination of claim 16, wherein the liquid delivery means is a pump or a wick having greater capillarity than the wicking structure.
- 56. A fuel reservoir for a liquid fuel cell, comprising:
(a) a container having a wall and an interior defining a cavity holding a liquid fuel for the liquid fuel cell; (b) a wicking structure disposed within the cavity and into which at least a portion of the liquid fuel wicks and from which the liquid fuel may subsequently be delivered, wherein substantially all of the free liquid fuel in the container is contactable by the wicking structure, wherein the wicking structure has a longest dimension and the free rise wick height of the wicking structure is greater than at least one half of the longest dimension; (c) an outlet that provides fluid communication of the wicking structure through the wall of the container to a location exterior of the container; and (d) a liquid delivery means interspersed between the outlet and the location exterior of the container, wherein the liquid delivery means delivers the liquid fuel from the outlet to the location exterior of the container.
- 57. A fuel reservoir for a liquid fuel cell, comprising:
(a) a container having a flexible wall and an interior defining a cavity holding a liquid fuel for the liquid fuel cell; (b) a wicking structure disposed within the cavity and into which at least a portion of the liquid fuel wicks and from which the liquid fuel may subsequently be delivered, wherein substantially all of the free liquid fuel in the container is contactable by the wicking structure, wherein the wicking structure has a longest dimension and the free rise wick height of the wicking structure is greater than at least one half of the longest dimension; and (c) an outlet that provides fluid communication of the wicking structure through the wall of the container to a location exterior of the container.
- 58. A combination, comprising:
(i) a recyclable fuel reservoir, wherein said recyclable fuel reservoir comprises
(a) a container having a wall and an interior defining a cavity holding a liquid fuel for the liquid fuel cell; (b) a wicking structure disposed within the cavity and into which at least a portion of the liquid fuel wicks and from which the liquid fuel may subsequently be delivered, wherein substantially all of the free liquid fuel in the container is contactable by the wicking structure, wherein the wicking structure has a longest dimension and the free rise wick height of the wicking structure is greater than at least one half of the longest dimension; and (c) an outlet that provides fluid communication of the wicking structure through the wall of the container to a location exterior of the container, said outlet having a valve or a sealable cap containing a membrane, wherein the membrane can be punctured by a needle for liquid fuel introduction and the membrane seals the cavity after the liquid fuel introduction; and (ii) a liquid fuel cell comprising an anode, wherein the anode is in fluid communication with the outlet of the recyclable fuel reservoir.
Parent Case Info
[0001] This application claims the benefit of U.S. Provisional Patent Application No.______ , entitled “Liquid Fuel Delivery System for Fuel Cells”, filed on Jun. 28, 2001 by the instant inventors, the disclosure of which is incorporated by reference.