Fuel cell electrode interconnect contact material encapsulation and method

Patent metadata

Field	Value
Publication number	US-9356300-B2
Application number	US-201314036342-A
Country	US
Kind code	B2
Filing date	Sep 25, 2013
Priority date	Sep 25, 2013
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

A fuel cell stack includes a plurality of fuel cell cassettes each including a fuel cell with an anode and a cathode. Each fuel cell cassette also includes an electrode interconnect adjacent to the anode or the cathode for providing electrical communication between an adjacent fuel cell cassette and the anode or the cathode. The interconnect includes a plurality of electrode interconnect protrusions defining a flow passage along the anode or the cathode for communicating oxidant or fuel to the anode or the cathode. An electrically conductive material is disposed between at least one of the electrode interconnect protrusions and the anode or the cathode in order to provide a stable electrical contact between the electrode interconnect and the anode or cathode. An encapsulating arrangement segregates the electrically conductive material from the flow passage thereby, preventing volatilization of the electrically conductive material in use of the fuel cell stack.

First claim

We claim:

1. A fuel cell stack having a plurality of fuel cell cassettes, each said fuel cell cassette comprising:
a fuel cell with an anode and a cathode;
an electrode interconnect adjacent to one of said anode and said cathode for providing electrical communication between an adjacent said fuel cell cassette and said one of said anode and said cathode, said electrode interconnect having a plurality of electrode interconnect protrusions defining a flow passage along said one of said anode and said cathode for communicating one of an oxidant and a fuel to said one of said anode and said cathode;
an electrically conductive material disposed between at least one of said plurality of electrode interconnect protrusions and said one of said anode and said cathode in order to provide an electrical contact between said electrode interconnect and said one of said anode and said cathode; and
an encapsulating arrangement that radially surrounds said electrically conductive material and segregates said electrically conductive material from the flow of said one of said oxidant and said fuel in said flow passage, thereby preventing volatilization of said electrically conductive material by said one of said oxidant and said fuel in use of said fuel cell stack.

2. A fuel cell stack as in claim 1 wherein said electrode interconnect is a cathode interconnect and said plurality of electrode interconnect protrusions define a cathode flow passage for communicating said oxidant to said cathode.

3. A fuel cell stack as in claim 1 wherein said encapsulating arrangement comprises a recess extending into said at least one of said plurality of electrode interconnect protrusions such that said recess in said at least one of said plurality of electrode interconnect protrusions defines a material cavity with said one of said anode and said cathode.

4. A fuel cell stack as in claim 3 wherein said electrode interconnect is a cathode interconnect and said plurality of electrode interconnect protrusions define a cathode flow passage for communicating said oxidant to said cathode.

5. A fuel cell stack as in claim 4 wherein said electrically conductive material comprises silver.

6. A fuel cell stack as in claim 5 wherein said electrically conductive material further comprises palladium.

7. A fuel cell stack as in claim 1 wherein said encapsulating arrangement comprises a glass ring radially surrounding said electrically conductive material and disposed between said at least one of said plurality of electrode interconnect protrusions and said one of said anode and said cathode.

8. A fuel cell stack as in claim 1 wherein said encapsulating arrangement comprises a skin formed on said electrically conductive material.

9. A fuel cell stack as in claim 8 wherein said skin comprises silica.

10. A method of forming a fuel cell stack having a plurality of fuel cell cassettes where each fuel cassette comprises a fuel cell with an anode and a cathode; an electrode interconnect adjacent to one of said anode and said cathode for providing electrical communication between an adjacent said fuel cell cassette and said one of said anode and said cathode, said electrode interconnect having a plurality of electrode interconnect protrusions defining a flow passage along said one of said anode and said cathode for communicating one of an oxidant and a fuel to said one of said anode and said cathode; and an electrically conductive material disposed between at least one of said plurality of electrode interconnect protrusions and said one of said anode and said cathode in order to provide an electrical contact between said electrode interconnect and said one of said anode and said cathode, said method comprising:
providing an encapsulating arrangement which radially surrounds said electrically conductive material and segregates said electrically conductive material from said flow passage, thereby preventing volatilization of said electrically conductive material in use of said fuel cell stack.

11. A method as in claim 10 wherein said step of providing said encapsulating arrangement comprises:
forming a recess extending into said at least one of said plurality of electrode interconnect protrusions to define a material cavity with said one of said anode and said cathode; and
disposing said electrically conductive material within said material cavity.

12. A method as in claim 10 wherein said step of providing said encapsulating arrangement comprises radially surrounding said electrically conductive material with a glass ring disposed between said at least one of said plurality of electrode interconnect protrusions and said one of said anode and said cathode.

13. A method as in claim 12 wherein said step of providing said encapsulating arrangement further comprises:
disposing a ring of glass paste between said at least one of said plurality of electrode interconnect protrusions and said one of said anode and said cathode;
disposing said electrically conductive material between said at least one of said plurality of electrode interconnect protrusions and said one of said anode and said cathode; and
sintering said ring of glass paste to form said glass ring.

14. A method as in claim 10 wherein said step of providing said encapsulating arrangement comprises forming a skin on said electrically conductive material.

15. A method as in claim 14 wherein said step of providing said encapsulating arrangement further comprises:
mixing said electrically conductive material with silicon and an organic liquid carrier to form an electrically conductive material/silicon paste;
disposing said electrically conductive material/silicon paste between said at least one of said plurality of electrode interconnect protrusions and said one of said anode and said cathode; and
sintering said electrically conductive material/silicon paste after said step of disposing said electrically conductive material/silicon paste to oxidize said silicon to form silica, thereby causing said silica to migrate toward said flow passage and form said skin.

16. A method as in claim 15 wherein said electrically conductive material/silicon paste is about 1% to about 10% silicon by volume.

Assignees

• Delphi Tech Inc

Inventors

• Derose Anthony J
• Haltiner Jr Karl J
• Gudyka Russell A
• Bonadies Joseph V
• Silvis Thomas W

Classifications

• H01M8/0282

  Inorganic material · CPC title

• H01M8/0202 Primary

  Collectors; Separators, e.g. bipolar separators; Interconnectors · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• H01M8/0271

  Sealing or supporting means around electrodes, matrices or membranes · CPC title

• H01M8/0297

  Arrangements for joining electrodes, reservoir layers, heat exchange units or bipolar separators to each other (H01M8/0271 takes precedence) · CPC title