Fuel cells incorporating nanotubes in fuel feed

• US 6,589,682 B1
• Filed: 08/18/2000
• Issued: 07/08/2003
• Est. Priority Date: 01/27/2000
• Status: Expired due to Fees

• Current Assignee: Cynthia Buenviaje, David Lim, Feng Zheng, Fuji H. Sho, Jeff Pedersen, Jeremy Hergesheimer, Karen Fleckner, Michael Treiber, Yao Huang
• Original Assignee: Cynthia Buenviaje, David Lim, Feng Zheng, Fuji H. Sho, Jeff Pedersen, Jeremy Hergesheimer, Karen Fleckner, Michael Treiber, Yao Huang
• Inventors: Zheng, Feng, Lim, David, Pedersen, Jeff, Huang, Yao, Fleckner, Karen, Buenviaje, Cynthia, Treiber, Michael, Fuji, H. Sho, Hergesheimer, Jeremy
• Primary Examiner(s): Chaney, Carol
• Assistant Examiner(s): YUAN, DAH WEI D
• Application Number:
  US09/642,198
• Time in Patent Office: 1,054 Days
• Field of Search: 429/34, 429/37, 429/38, 429/46
• US Class Current: 429/458
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/0432 Temperature; Ambient temperature
• CPC Class Codes: H01M 8/04388 of anode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04395 of cathode reactants at the inlet or inside the fuel cell
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04589 of fuel cell stacks
• CPC Class Codes: H01M 8/04649 of fuel cell stacks
• CPC Class Codes: H01M 8/04701 Temperature
• CPC Class Codes: H01M 8/04753 of fuel cell reactants
• CPC Class Codes: H01M 8/04761 of fuel cell exhausts
• CPC Class Codes: H01M 8/0488 of fuel cell stacks
• CPC Class Codes: H01M 8/0491 of fuel cell stacks
• CPC Class Codes: H01M 8/04952 of fuel cell stacks
• CPC Class Codes: H01M 8/04992 characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 977/948 Energy storage/generating using nanostructure, e.g. fuel cell, battery

Abstract

A novel design and process for: a) a membrane electrode assembly (MEA) with aligned carbon nanotubes as a nano-scale gas distributor which yield better gas conversion efficiencies in PEM fuel cells, and (b) doped silicon flow field plates (FFP) which increase electrode conductivity of the membrane-catalyst-gas diffusion layer (GDL)-FFP interfaces of the proton exchange membrane fuel cell (PEMFC). Also, part of the invention are a stacking configuration and a gas distribution design that also enhance conductivity of carbon/metal catalyst/electrode, GDL, and FFP interfaces surfaces without crushing the FFPs. Aligned carbon nanoscale gas distributors are employed at the interfaces, thereby increasing the overall performance of the PEMFC. The FFPs are easy to manufacture and mass-producible, yet mechanically sturdy and significantly lighter in weigh than their conventional counterparts. Another novel feature of the invention is an integrated monitoring and communication/Internet system located directly or connected to the FFP.

Claims

1. A fuel cell which comprises:

first and second flow field plates;

an electrolyte between the flow field plates;

catalytic electrodes on first and second, opposite faces of the electrolyte for promoting the dissociation of a fuel at the first face of said electrolyte and the formation of water at the second face of the electrolyte, and

a system for delivering a gaseous fuel through the first flow field plate to the first face of the electrolyte, said system comprising an array of nanotubes oriented to discharge said fuel into contact with the catalyst on the first face of the electrolyte.

2. A fuel cell as defined in claim 1 in which the nanotubes are carbon fullerenes.

3. A fuel cell as defined in claim 1 in which the nanotubes are impregnated in said first flow field plate.

4. A fuel cell as defined in claim 1 in which said nanotubes are attached to a surface of said first flow field plate.

5. A fuel cell as defined in claim 4 in which said nanotubes are attached to the flow field plate by sputtering.

6. A fuel cell as defined in claim 4 in which the nanotubes are attached to the flow field plate by chemical vapor deposition.

7. A fuel cell as defined in claim 4 in which the flow field plates are attached to the flow field plate by physical vapor deposition.

8. A fuel cell as defined in claim 1 in which the nanotubes are placed only on selected areas of the FFP.

9. A fuel cell as defined in claim 1 in which the gaseous fuel delivery system:

comprises gas inlet channels in the flow field plate to which the fuel can be transferred from an external source;

said nanotubes being in fluid communication with said gas inlet channels.

10. A fuel cell as defined in claim 1 which has a system comprising an array of aligned nanotubes for delivering a gaseous oxidizer into contact with the catalyst on the second face of the electrolyte.

11. A fuel cell as defined in claim 1 in which the electrolyte is a proton exchange membrane.

12. A fuel cell as defined in claim 1 which includes circuitry comprising said nanotubes for conducting electrons liberated at the first face of the electrolyte to an external load.

13. A fuel cell as defined in claim 1 in which said nanotubes are impregnated in a carrier and said carrier is placed on said the face of the electrolyte.

14. An electrical power generation device comprises a stacked array of fuel cells as defined in claim 1.

15. An assembly for a fuel cell comprising:

an electrolyte membrane;

a plurality of catalyst sites on first and second, opposite faces of the electrolyte for promoting the disassociation of a gaseous fuel at the first face and the formation of a byproduct at the second face;

a plurality of electrically-conductive nanotubes oriented to conduct a gaseous fuel to the plurality of catalyst sites on the first face of the electrolyte, the nanotubes being electrically connected to the catalyst sites to receive an electrical current therefrom.

16. The assembly of claim 15 wherein the nanotubes have a first aperture proximate to catalyst on the first surface of the electrolyte and a second aperture remote therefrom, the apertures being of sufficient size that fuel can enter the nanotubes through the remote aperture assembly further comprising a first flow field plate for conducting a gaseous fuel to the second apertures of the nanotubes.

17. The assembly of claim 15 wherein the nanotubes are embedded in a layer of gas diffusion layer material.

18. The assembly of claim 16 wherein the nanotubes are embedded in an electrically-conductive layer of a gas diffusion layer material.

19. The assembly of claim 16 wherein the nanotubes extend through a conductive layer such that the first apertures of the nanotubes are on one side of the layer and the second apertures of the nanotubes are on the other, and wherein the nanotubes are electrically connected to the conductive layer.

20. The assembly of claim 15 wherein the electrolyte membrane comprises a proton exchange membrane.

21. The assembly of claim 15 wherein the electrolyte membrane blocks the flow of the gaseous fuel from the first side of the membrane to the second side of the membrane.

22. The assembly of claim 21 wherein the nanotubes have a first aperture proximate to catalyst on the first surface of the electrolyte and a second aperture remote therefrom, the apertures being of sufficient size that fuel can enter the nanotubes through the remote aperture assembly further comprising a first flow field plate for conducting a gaseous fuel to the second apertures of the nanotubes.

23. The assembly of claim 22 wherein the nanotubes are embedded in an electrically-conductive layer of a gas diffusion layer material.

24. The assembly of claim 22 wherein the nanotubes extend through a conductive layer such that the first apertures of the nanotubes are on one side of the layer and the second apertures of the nanotubes are on the other, and wherein the nanotubes are electrically connected to the conductive layer.

25. The assembly of claim 24 wherein the nanotubes are fullerenes.