IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0266965
(2002-10-08)
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발명자
/ 주소 |
- Bhaskar, Sompalli
- Gasteiger, Hubert
- Litteer, Brian A.
|
인용정보 |
피인용 횟수 :
10 인용 특허 :
7 |
초록
▼
A membrane electrode assembly comprising an ionically conductive member and an electrode, wherein the electrode is a smooth, continuous layer that completely covers and supports the ionically conductive member. The electrode further comprises a central region and a peripheral region, wherein a gradi
A membrane electrode assembly comprising an ionically conductive member and an electrode, wherein the electrode is a smooth, continuous layer that completely covers and supports the ionically conductive member. The electrode further comprises a central region and a peripheral region, wherein a gradient of electrochemically active material exists between the central region and the peripheral region such that a content of the electrochemically active material is greater in the central region than the peripheral region.
대표청구항
▼
1. An assembly for a fuel cell comprising:an ionically conductive membrane having a major surface; an electrode adjacent said major surface and having a peripheral extent essentially the same as said major surface, said electrode, including a central region, and a peripheral region; said central reg
1. An assembly for a fuel cell comprising:an ionically conductive membrane having a major surface; an electrode adjacent said major surface and having a peripheral extent essentially the same as said major surface, said electrode, including a central region, and a peripheral region; said central region comprising a binder and a first group of particles and said peripheral region comprising a binder and a second group of particles; and wherein said first group of particles is catalyzed, and said second group of particles is uncatalyzed or has a catalyst content less than the catalyst content of said first group of particles. 2. The assembly according to claim 1, wherein said catalyzed particles are catalyzed carbon particles, and said binder of said central and peripheral regions is the same.3. The assembly according to claim 2, wherein said carbon particles have a particle size equal to or less than 15 μm.4. The assembly according to claim 2, wherein said catalyst is selected from the group consisting of platinum, palladium, titanium, ruthenium, rhodium, tungsten, tin, molybdenum, and alloys thereof.5. The assembly according to claim 1, wherein said central region and said peripheral region each provide substantially similar mechanical support to the ionically conductive member, thereby minimizing flexing of said membrane.6. The assembly according to claim 1, which further comprises an electrically conductive member adjacent to said electrode, said electrically conductive member is a gas diffusion medium selected from the group consisting of carbon cloth, carbon foam, and carbon paper.7. The assembly according to claim 1, wherein said peripheral region is thermally conductive.8. The assembly according to claim 1, wherein said electrode is in the form of a continuous layer, and said peripheral region encompasses said central region.9. The assembly according to claim 5, wherein said peripheral region minimizes contact between said electrically conductive member and said membrane.10. The assembly according to claim 1, wherein said peripheral region is electrically conductive.11. The assembly according to claim 2, wherein said membrane comprises a polymeric ionomer which is the same as said binder of said central and peripheral region.12. A membrane electrode assembly comprising:an ionically conductive membrane having a major surface; an electrode at said major surface, said electrode defining a continuous layer supporting said membrane and comprising a central region and a peripheral region; and wherein a gradient of electrochemically active material exists between said central region and said peripheral region such that a content of said electrochemically active material is greater in said central region than said peripheral region. 13. The membrane electrode assembly according to claim 12, wherein said electrode restricts movement of said membrane.14. The membrane electrode assembly according to claim 12, wherein said electrode layer further comprises a sealing region outboard of said peripheral region, wherein said central, peripheral and sealing regions collectively form said continuous layer and provide continuous, consistent mechanical support to the membrane, thereby minimizing flexing of said membrane.15. The membrane electrode assembly according to claim 12, which further comprises an electrically conductive member adjacent said electrode, and wherein said electrode layer maintains said electrically conductive member spaced from said ionically conductive member.16. An assembly for a fuel cell comprising:a proton exchange membrane with a first surface and a second surface; an anode electrode disposed at said first surface; a cathode electrode opposing said anode, and disposed at said second surface; gas diffusion media disposed at said anode and cathode, said anode electrode and said cathode electrode each comprising a central region and a peripheral region; said central region including an electrochemically active material; and said peripheral region including a thermally conductive material and a sealing material; and wherein said anode and said cathode are each in the form of continuous layers that support said proton exchange membrane, minimize flexing of said membrane, and prevent said gas diffusion media from contacting said proton exchange membrane. 17. The assembly according to claim 16, wherein said electrochemically active material comprises a plurality of catalyst-coated particles dispersed in an ionomer.18. The assembly according to claim 16, wherein said thermally conductive material comprises a plurality of particles dispersed in an ionomer.19. The assembly according to claim 18, wherein said thermally conductive material is also electrically conductive.20. The assembly according to claim 16, wherein said sealing material is a thermoplastic resin.21. The assembly according to claim 16, wherein said thermally conductive material is adjacent to said central region and said sealing material is outboard of said thermally conductive material.22. A method for manufacturing an electrode for a membrane electrode assembly, comprising:applying a first casting solution to a first region on a surface of a substrate, said first casting solution comprising carbon particles and an ionomer; applying a second casting solution to a second region of said surface of said substrate, said second casting solution comprising carbon particles and an ionomer; wherein said first region is a centrally located region on the surface of said substrate, and said second region is outboard of said centrally located region on the surface of said substrate; wherein said first solution comprises catalyst and said second solution has less catalyst content than said first solution; and drying each of said applied solutions to form a continuous electrode film. 23. The method of claim 22 wherein said second casting solution is applied before said first casting solution has dried to a film.24. The method of claim 22 wherein said second solution does not contain catalyst.25. The method of claim 22 wherein said substrate is an ionically conductive membrane.26. The method of claim 22 wherein said continuous electrode film is removed from said substrate and then pressed to an ionically conductive membrane, thereby forming a membrane electrode assembly.
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