Surface replica fuel cell for micro fuel cell electrical power pack

• US 5,759,712 A
• Filed: 01/06/1997
• Issued: 06/02/1998
• Est. Priority Date: 01/06/1997
• Status: Expired due to Term

• Current Assignee: Digital Equipment Corporation (HP Inc.), Manhattan Scientifics Inc.
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Hockaday, Robert G.
• Primary Examiner(s): Skapars, Anthony
• Application Number:
  US08/779,106
• Time in Patent Office: 512 Days
• Field of Search: 429/19, 429/26, 429/30, 429/34, 429/35, 429/40, 429/42
• US Class Current: 429/423
• CPC Class Codes: H01M 16/006 of fuel cells with rechargeable batteries
• CPC Class Codes: H01M 8/0206 Metals or alloys
• 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 8/04119 with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying
• CPC Class Codes: H01M 8/04141 by water containing exhaust gases
• CPC Class Codes: H01M 8/04149 by diffusion, e.g. making use of membranes
• 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 8/04208 Cartridges, cryogenic media or cryogenic reservoirs
• CPC Class Codes: H01M 8/04291 Arrangements for managing water in solid electrolyte fuel cell systems H01M8/04119 takes precedence
• CPC Class Codes: H01M 8/0488 of fuel cell stacks
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: H01M 8/1007 with both reactants being gaseous or vaporised 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 8/1023 having only carbon, e.g. polyarylenes, polystyrenes or polybutadiene-styrenes
• CPC Class Codes: H01M 8/1039 halogenated, e.g. sulfonated polyvinylidene fluorides
• CPC Class Codes: H01M 8/1081 starting from solutions, dispersions or slurries exclusively of polymers
• 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 8/242 comprising framed electrodes or intermediary frame-like gaskets H01M8/2425, H01M8/244 take precedence
• CPC Class Codes: H01M 8/2457 : with both reactants being gaseous or vaporised
• CPC Class Codes: H01M 8/2483 : characterised by internal manifolds
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 70/50 : Manufacturing or production processes characterised by the final manufactured product

Abstract

A miniature fuel cell system uses porous plastic membranes as substrates of fuel cells. A cost effective pore-free electrode or inter electrolyte foil that is permeable only to hydrogen as an ion. The new electrode makes direct alcohol fuel cells efficient. It blocks the poisoning alcohol diffusion through the electrolyte. Compound electrodes are formed by vacuum deposition methods and slurries. That leads to printed circuit designs of small fuel cells systems integrated with rechargeable batteries and electrical power electronics to power applications that are currently powered by batteries. By directly utilizing alcohol fuels the new fuel cells have higher energy per unit mass and higher energy per unit volume. They are more convenient for the energy user, environmentally less harmful and less expensive than conventional batteries.

Claims

1. A fuel cell apparatus comprising a central membrane having an oxygen side and a fuel side, electrodes positioned on the fuel side and on the oxygen side of the membrane, each electrode further comprising a first fuel catalyst film layer deposited on the central membrane, metal film layers deposited over the catalyst film layer, and hydrophobic film layers positioned on the metal film layers, an electrolyte disposed in voids between the catalyst film layer and the central membrane, a hydrogen permeable pore-free metal membrane interposed between the electrodes, the central membrane having a first water circulating, a fuel circulating and regulating membrane positioned above the electrode on the fuel side, a fuel channel flow manifold positioned above the first water circulating and regulating membrane and sealed to the electrode on the fuel side, a fuel inlet connected to the fuel manifold for delivering fuel to a region between the fuel manifold and the first water circulating and regulating membrane, a second water circulating and regulating membrane positioned below the electrode on the oxygen side, an oxidizer gas manifold positioned below the second water circulating and regulating membrane and sealed to the electrode on the oxygen side, and an oxidizer gas inlet connected to the oxidizer gas manifold for delivering oxidizer gas to a region between the oxidizer gas manifold and the second water circulating and regulating membrane, a first electrical contact connected to the hydrogen electrode and a second electrical contact connected to the oxygen electrode, and a sealing rim extending around and connected to outer edges of the cell.

2. The apparatus of claim 1, wherein the central membrane is a porous dielectric membrane.

3. The apparatus of claim 1, further comprising a fuel bottle attached to the fuel cell.

4. The apparatus of claim 1, further comprising a housing for enclosing the cell.

5. The apparatus of claim 1, further comprising an energy source attached to the electrodes for delivering electrical energy.

6. The apparatus of claim 5, wherein the energy source is voltage regulating electronics.

7. The apparatus of claim 5, wherein the energy source is a battery.

8. The apparatus of claim 1, wherein the central membrane is reinforced with fibers.

9. The apparatus of claim 1 wherein the central membrane comprises at least two membranes.

10. The apparatus of claim 3, wherein the fuel bottle comprises a needle insert for effecting a fuel connection with the fuel cell.

11. The apparatus of claim 3, further comprising an evaporative manifold for wicking out fuel from the fuel bottle to the evaporative manifold.

12. The apparatus of claim 4, further comprising the electrodes being on one side of the membrane, and a fold of the membrane is for forming the fuel side and the oxygen side and for positioning the electrodes opposite each other to form the fuel cell.

13. The apparatus of claim 12, further comprising an electrolyte and membranes interposed into the fold of the membrane.

14. The apparatus of claim 12, further comprising an electrolyte interposed into the fold of the membrane.

15. The apparatus of claim 12, further comprising membranes interposed into the fold of the membrane.

16. The apparatus of claim 2, further comprising microscopic geometry on the porous dielectric substrate membrane for enhancing electrolyte properties.

17. The apparatus of claim 1 further comprising additional members interposed in the electrolyte for selectively blocking different molecular species over ion transport based on geometrical designs or chemical properties of the species.

18. The apparatus of claim 1, wherein the fuel is a hydrogen bearing compound.

19. The apparatus of claim 1, wherein the fuel is a hydrogen bearing compound used electrocatalytically by the fuel cell electrodes.

20. The apparatus of claim 18, wherein the fuel is reformed before reaching the fuel cell electrodes.

21. The apparatus of claim 1, wherein the hydrogen permeable pore-free metal membrane interposed between the fuel and oxygen electrodes is electrically connected to the fuel electrodes.

22. The apparatus of claim 1, wherein the hydrogen permeable pore-free metal membrane interposed between the fuel and oxygen electrodes is electrically connected to the oxidizer electrodes.

23. The apparatus of claim 1, further comprising the electrodes having multiple electrode and electrolyte layers on a porous substrate.

24. The apparatus of claim 1, further comprising deposits on surfaces of the films for cell electrical separations.

25. The apparatus of claim 24, wherein the deposits comprise ink jet printing deposits.

26. The apparatus of claim 24, wherein the deposits comprise paints.

27. The apparatus of claim 24, wherein the deposits comprise vapors deposited by a method selected from a group comprising chemical vapor deposition, photolithography, vacuum deposition or electrochemical deposition.

28. The apparatus of claim 1, further comprising voltage regulation electronics electrically connected to the fuel cell for pulse cleaning of the electrodes, for maintaining performance of the fuel cell, and for changing voltages in the same or opposite polarity of the fuel cell.

29. The apparatus of claim 1, further comprising the fuel cell having a profile to fit into batteries and electrical profiles for matching existing uses of batteries.

30. The apparatus of claim 1, wherein the fuel cell is a thin bag having fuel on an inside and air on an outside.

31. The apparatus of claim 30, further comprising a backing membrane on the bag for allowing exhaust gases diffuse out and retaining the fuel gases.

32. The apparatus of claim 1, wherein the fuel cell comprises at least two back to back fuel cell assemblies.

33. The apparatus of claim 2, wherein the fuel bottle is a replaceable sealed ampoule of fuel.

34. The apparatus of claim 2, further comprising electronics connected to the fuel cell for regulating a voltage and a current output of the fuel cell to produce desired voltage and current characteristics, including alternating current, arbitrary wave functions, and steady voltage.

35. The apparatus of claim 1, further comprising at least two different electrolytes separated by the pore-free metal membrane.

36. The apparatus of claim 1, wherein the pore-free metal membrane comprises at least one film of a material deposited on a porous substrate for plugging the pores of the substrate.

37. The apparatus of claim 1, wherein the at least one film contains at least one transition element from the periodic table of elements.

38. The apparatus of claim 1, further comprising at least two electrodes forming the fuel electrode, each comprising a base electrode and a surface replica electrode, with the electrode being formed by deposition techniques of sputtering, vacuum evaporation, powder ink spraying, xerography, low pressure gas vapor deposition, chemical vapor deposition, electroplating, photolithography, or co-deposited materials.

39. The apparatus of claim 1, wherein the fuel cell is adapted to drive electronics goods.

40. The apparatus of claim 39, wherein the electronics goods is selected from a group consisting of cellular phones, portable radios, portable computers, pagers, portable audio equipment, hearing aids, medical equipment, or portable electronics.

41. The apparatus of claim 36, wherein the porous substrate material has a porosity collimated perpendicular to a plane of the material by use of drawing inks and solvents vertically, into the material rather than lateral blotting.

42. The apparatus of claim 41, wherein the material having ink are powders in a solvent.

43. The apparatus of claim 41, wherein the material comprises substances that change to electrode films after being delivered to the substrate.

44. The apparatus of claim 1, wherein the electrolyte is collimated for preventing lateral conduction through the electrolyte and preventing electrical shorting.

45. The apparatus of claim 1, wherein the fuel cells comprise side by side non-bipolar fuel cell series cells on a single membrane having different potentials.

46. The apparatus of claim 45, wherein the electrolyte is collimated for confining the pore-free membrane pinhole defect leaks from laterally affecting fuel cell electrode performance.

47. The apparatus of claim 1, further comprising a water and heat counter flow heat exchanger for humidifying and heating air entering the fuel cell.

48. The apparatus of claim 1, wherein the electrodes have tapered thickness for optimizing use of a bulk conductor metal.

49. The apparatus of claim 1, further comprising a wick for wicking liquid fuel out of the fuel tank, vaporizing fuel from the wick and condensing fuel on the fuel cell.

50. The apparatus of claim 1, wherein the fuel comprises a stoichiometric mixture of water and hydrocarbon for direct hydrocarbon electrocatalyst oxidation and for liberation of hydrogen to the fuel cell.

51. The apparatus of claim 31, wherein the fuel comprises a 1:

1 molar mixture of methanol and water, and wherein exhaust carbon dioxide product exits as a gas through a membrane permeable to carbon dioxide and impermeable to methanol and water.

52. The apparatus of claim 1, further comprising a selectively permeable membrane proximal to the fuel cell electrode for excluding selected molecular species and allowing others to pass through.

53. The apparatus of claim 1, further comprising a selectively permeable membrane formed as part of the gas manifold for excluding selected molecular species and allowing others to pass through.