Interconnect

Patent metadata

Field	Value
Publication number	US-10096843-B2
Application number	US-201514641745-A
Country	US
Kind code	B2
Filing date	Mar 9, 2015
Priority date	Feb 10, 2015
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

An interconnect for a low temperature solid oxide fuel cell, the interconnect comprising: a stainless steel substrate comprising a first surface and a second surface; a layer comprising chromium oxide on the first surface of the substrate, wherein the chromium oxide layer has a thickness in the range of 350-600 nm; and a metal oxide coating on the chromium oxide layer. A process for making an interconnect for a low temperature solid oxide fuel cell, the process comprising: coating a first surface of a stainless steel substrate with a metal oxide to form a coated substrate; and heating the coated substrate to a temperature in the range of 800-900° C. to form a layer comprising chromium oxide between the first surface and the metal oxide coating.

First claim

We claim:

1. An interconnect for a low temperature solid oxide fuel cell, the interconnect comprising:
a stainless steel substrate comprising a first surface and an opposed second surface for use on the an air/oxidant side and a fuel side of the interconnect, respectively;
a layer comprising chromium oxide on the first surface of the substrate, wherein the chromium oxide layer has a thickness in the range of 350 nm to 600 nm;
a metal oxide coating on the chromium oxide layer; and
a continuous aluminum oxide layer directly on the second surface of the substrate, there being no intervening layer between the continuous aluminum oxide layer and the second surface.

2. The interconnect according to claim 1 , wherein the chromium oxide layer is an oxide scale.

3. The interconnect according to claim 1 , wherein the stainless steel comprises 17 wt % to 25 wt % chromium.

4. The interconnect according to claim 3 , wherein the stainless steel is a ferritic stainless steel.

5. The interconnect according to claim 1 , wherein the metal oxide comprises a metal oxide selected from cobalt oxide, manganese cobalt oxide, copper oxide or combinations thereof.

6. The interconnect according to claim 1 , wherein the metal oxide coating has a thickness in the range of 0.5 μm to 20 μm.

7. The interconnect according to claim 1 , wherein the chromium oxide layer has a thickness in the range of 350 nm to 500 nm.

8. The interconnect according to claim 1 , wherein the chromium oxide layer has a thickness in the range of 350 nm to 450 nm.

9. The interconnect according to claim 1 , wherein the metal oxide coating comprises cobalt oxide.

10. A fuel cell stack comprising at least one interconnect according to claim 1 .

11. The fuel cell stack according to claim 10 , wherein a cathode contact paste, or contact layer is present between the cathode and a cathode side of at least one interconnect.

12. A fuel cell stack according to claim 10 , wherein the metal oxide coating is in contact with the air supplying the fuel cell.

13. A process for making an interconnect for a low temperature solid oxide fuel cell, the process comprising:
coating a first surface of a stainless steel substrate with a metal oxide coating to form a coated substrate;
heating the coated substrate to a temperature in the range of 800° C. to 920° C. to form a layer comprising a chromium oxide between the first surface and the metal oxide coating; and
resulting in the interconnect for the low temperature solid oxide fuel cell comprising:
the stainless steel substrate comprising the first surface and an opposed second surface for use on an air/oxidant side and a fuel side of the interconnect, respectively;

the layer comprising the chromium oxide on the first surface of the substrate, wherein the chromium oxide layer has a thickness in the range of 350 nm to 600 nm;
the metal oxide coating on the chromium oxide layer; and
a continuous aluminum oxide layer directly on the second surface of the substrate, there being no intervening layer between the continuous aluminum oxide layer and the second surface.

14. The process according to claim 13 , wherein the coated substrate is heated for a time in the range of 3 hours to 6 hours.

15. The process according to claim 13 , wherein the coating is applied to the substrate by a method selected from, vapour deposition, printing, roll-to-roll processing, spraying, or combinations thereof.

16. The process according to claim 13 , wherein the coating is applied to the substrate by a method comprising:
providing a metallic layer and a reactive layer on the stainless steel substrate,
allowing the metallic layer and the reactive layer to react with each other or diffuse into each other, and
oxidizing the metallic layer and the reactive layer to form the metal oxide coating.

17. The process according to claim 13 , wherein an interconnect form is provided by processing either prior to heating the coated substrate, or after heating the coated substrate.

Assignees

• Ceres Ip Co Ltd

Inventors

• Leah Robert
• Selcuk Ahmet

Classifications

• H01M8/021 Primary

  Alloys based on iron · CPC title

• H01M8/124

  characterised by the process of manufacturing or by the material of the electrolyte · CPC title

• C23C16/40

  Oxides · CPC title

• H01M8/0228 Primary

  in the form of layered or coated products · CPC title

• C23C8/10

  Oxidising · CPC title