Microfabricated Fuel Cell

• US 20080050637A1
• Filed: 08/22/2007
• Published: 02/28/2008
• Est. Priority Date: 08/22/2006
• Status: Abandoned Application

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Bhusari, Dhananjay, Kohl, Paul, Prakash, Shruti
• Application Number:
  US11/843,634
• Publication Number:
  US 20080050637A1
• Time in Patent Office: Days
• US Class Current: 429/34
• 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 8/0269 Separators, collectors or interconnectors including a printed circuit board
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] 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 8/1046 Mixtures of at least one polymer and at least one additive
• CPC Class Codes: H01M 8/1069 characterised by the manufacturing processes
• CPC Class Codes: H01M 8/1097 Fuel cells applied on a support, e.g. miniature fuel cells deposited on silica supports
• CPC Class Codes: H05K 1/16 incorporating printed electric components, e.g. printed resistor, capacitor, inductor
• 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

One or more microfabricated fuel cells may be integrated into a printed circuit board or a printed wiring board within an electronic device. The electrical energy created by the integrated microfabricated fuel cells within the metal wiring on the PWB may then be used by the electronic components within and on the PWB.

Claims

1. A method of making a microfabricated fuel cell integrated into a printed circuit board, the method comprising:

depositing at least one cathode current collector on the printed circuit board substrate;

creating at least one air hole through the printed circuit board substrate;

depositing a sacrificial polymer over the surface of the cathode current collector, patterning the sacrificial polymer in order to expose regions of the underlying cathode current collector;

depositing at least one cathode catalyst over the sacrificial polymer;

depositing a proton exchange membrane on the cathode catalyst;

removing the sacrificial polymer layer from between the cathode catalyst and the cathode current collector;

depositing at least one anode catalyst on the proton exchange membrane; and

providing a fuel for oxidation at the anode catalyst.

2. The method of claim 1, wherein the fuel is stored in a fuel reservoir which surrounds the at least one anode catalyst and is below the printed circuit board.

3. The method of claim 1, wherein an anode current collector is deposited on the anode catalyst.

4. The method of claim 1, wherein the anode catalyst includes at least one anode current collector.

5. The method of claim 1, wherein the cathode current collector comprises an electrical conductor selected from the group consisting of titanium, gold, copper, chromium, tungsten, tantalum, and combinations thereof.

6. The method of claim 1, wherein the depositing at least one cathode current collector comprises depositing a layer of titanium followed by a layer of gold.

7. The method of claim 6, wherein the layer of titanium is approximately 200 Å

thick and the layer of gold is approximately 600 Å

thick.

8. The method of claim 1, wherein the sacrificial polymer comprises at least one poly(propylene-carbonate) and at least one photoacid generator.

9. The method of claim 8, wherein the sacrificial polymer comprises at least 20% by weight of poly(propylene-carbonate) and at least 5% by weight of a photoacid generator.

10. The method of claim 1, wherein the sacrificial polymer is removed by thermal decomposition.

11. The method of claim 1, wherein the sacrificial polymer is a photo-patternable sacrificial polymer.

12. The method of claim 1, wherein the proton exchange membrane comprises a phosphorus doped silicon dioxide glass.

13. The method of claim 1, wherein the proton exchange membrane is deposited using plasma enhanced chemical vapor deposition (PECVD).

14. A method of making a microfabricated fuel cell integrated into a printed circuit board, the method comprising:

depositing at least one cathode current collector on the printed circuit board substrate;

depositing a photo resist mask on the cathode current collector;

patterning the photo resist mask to reveal at least one region of the cathode current collector;

removing the photo resist mask from the cathode current collector;

creating at least one air hole, wherein the air hole extends through the printed circuit board substrate;

depositing a sacrificial polymer over the surface of the cathode current collector;

depositing at least one cathode catalyst over the sacrificial polymer;

depositing a proton exchange membrane on the cathode catalyst;

removing the sacrificial polymer layer from between the cathode catalyst and the cathode current collector;

depositing at least one anode catalyst on the proton exchange membrane; and

providing a fuel for oxidation at the anode catalyst.

15. The method of claim 14, wherein the fuel is stored in a fuel reservoir which is below the printed circuit board.

16. The method of claim 14, wherein the anode catalyst includes an anode current collector.

17. The method of claim 14, wherein an anode current collector is deposited on the anode catalyst.

18. The method of claim 14 further comprising polishing the sacrificial polymer.

19. The method of claim 14, wherein the cathode current collector comprises an electrical conductor selected from the group consisting of titanium, gold, copper, chromium, tungsten, tantalum, and combinations thereof.

20. The method of claim 14, wherein the depositing at least one cathode current collector comprises depositing a first layer of titanium followed by a layer of gold and then followed by a second layer of titanium.

21. The method of claim 20, wherein the first and second layers of titanium are approximately 200 Å

thick and the layer of gold is approximately 600 Å

thick.

22. The method of claim 14, wherein the sacrificial polymer comprises at least one poly(propylene-carbonate) and at least one photoacid generator.

23. The method of claim 22, wherein the sacrificial polymer comprises at least 20% by weight of poly(propylene-carbonate) and at least 5% by weight of a photoacid generator.

24. The method of claim 14, wherein the sacrificial polymer is removed by thermal decomposition.

25. The method of claim 14, wherein the sacrificial polymer is a photo-patternable sacrificial polymer.

26. The method of claim 14, wherein the proton exchange membrane comprises a phosphorus doped silicon dioxide glass.

27. The method of claim 14, wherein the proton exchange membrane is deposited using plasma enhanced chemical vapor deposition (PECVD).

28. A microfabricated fuel cell integrated into a printed circuit board comprising:

at least one anode comprising an anode current collector deposited on an anode catalyst;

at least one cathode comprising a cathode current collector disposed between the printed circuit board and a cathode catalyst and at least one air hole extending through the printed circuit board and allowing ambient air to contact the cathode catalyst, wherein the cathode current collector is in electrical communication with the anode current collector;

at least one proton exchange membrane in contact with the cathode catalyst, wherein the anode catalyst is deposited on the proton exchange membrane; and

a fuel cell reservoir configured to deliver liquid fuel to the anode.

29. The microfabricated fuel cell of claim 28, wherein the anode is disposed below the printed circuit board.

30. The microfabricated fuel cell of claim 28, wherein the fuel cell reservoir is configured to prevent the liquid fuel from contacting the printed circuit board.

31. An electronic device comprising the microfabricated fuel cell of claim 28.