Methods of refurbishing components of a fuel cell stack
View Patent ↗Methods for refurbishing components, such as interconnects of a fuel cell stack, include singulating the stack and removing the electrolyte, seals and oxide layer using non-mechanical methods. The various methods of may be used either singly or in combination.
1. A method of singulating a fuel cell stack comprising a first end, a second end and a stacking dimension between the first end and the second end, a plurality of interconnects and a plurality of solid oxide fuel cells, each fuel cell positioned between adjacent interconnects along the stacking dimension of the fuel cell stack, and an internal conduit extending from the first end to the second end, through the plurality of interconnects and fuel cells, for conveying a fuel to or spent fuel from the plurality of fuel cells, the method comprising:
connecting a fluid source to the internal conduit at the first end of the stack;
applying fluid in the conduit through the plurality of interconnects and fuel cells; and
blocking the conduit in a first interconnect at the second end of the stack while leaving the conduit unblocked in at least one second interconnect in the stack such that a fluid pressure within the stack exceeds an adhesive strength of a sealing material in the stack, causing the first interconnect at the second end of the stack to completely separate from the fuel cell stack.
2. The method of claim 1 , wherein the fluid comprises a compressed fluid.
3. The method of claim 2 , wherein the fluid comprises air or water.
4. The method of claim 3 , wherein the fluid comprises the air having a pressure greater than 20 psig.
5. The method of claim 4 , wherein the air has a pressure between 90 and 125 psig.
6. The method of claim 1 , wherein the fluid is continuously applied through the conduit or the fluid is applied in one or more bursts.
7. The method of claim 1 , further comprising removing debris from the interconnect separated from the stack, wherein the debris comprises at least one of electrolyte material, seal material and chromium oxide material.
8. The method of claim 7 , wherein removing the debris comprises non-mechanically removing at least part of the debris from the interconnect.
9. The method of claim 8 , wherein the step of non-mechanically removing at least part of the debris comprises removing the debris by at least one of inductive heating, radiative heating, thermally heating in a reducing gas containing environment, chemical wet etching, or acoustic energy.
10. The method of claim 9 , wherein a first part of the fuel cell debris is non-mechanically removed from the interconnect.
11. The method of claim 10 , further comprising removing a second part of the debris by mechanical scraping.
12. The method of claim 11 , wherein substantially all of the debris is removed from the interconnect without grit blasting the interconnect.
13. The method of claim 1 , wherein the plurality of interconnects comprise chromium-iron alloy interconnects.