Oxygen getters for anode protection in a solid-oxide fuel cell stack

Abstract

In a fuel cell assembly, nickel-based anodes are readily oxidized when exposed to oxygen as may happen through atmospheric invasion of the assembly during cool-down following shutdown of the assembly. Repeated anode oxidation and reduction can be destructive of the anodes, leading to cracking and failure. To prevent such oxygen migration, oxygen getter devices containing oxygen-gettering material such as metallic nickel are provided in the fuel passageways leading to and from the anodes. Oxidation of the oxygen-gettering material is readily reversed through reduction by fuel when the assembly is restarted.

What is claimed is:  
     
         1 . In a fuel cell assembly including nickel-containing anodes and passageways leading to and from the anodes for conducting fuel to and from the anodes, the improvement comprising oxygen getter means disposed in each of said passageways for preventing gaseous oxygen from reaching and oxidizing said nickel in said anodes.  
     
     
         2 . An improvement in accordance with  claim 1  wherein said getter means comprises: 
 a) a passageway having an inlet and an outlet for passage of gas therethrough; and  
 b) reducing means disposed within said passageway for reacting with oxygen.  
 
     
     
         3 . A fuel cell assembly in accordance with  claim 2  wherein said reducing means includes metallic nickel.  
     
     
         4 . A fuel cell assembly in accordance with  claim 2  wherein said reducing means includes nickel alloy.  
     
     
         5 . A fuel cell assembly in accordance with  claim 3  wherein said metallic nickel is in a form selected from the group consisting of nickel metal foam, nickel wire, and nickel mesh.  
     
     
         6 . A fuel cell assembly in accordance with  claim 4  wherein said nickel alloy is in a form selected from the group consisting of nickel metal foam, nickel wire, and nickel mesh.  
     
     
         7 . A fuel cell assembly in accordance with claim I wherein said oxidation of said reducing means is reductively reversible by fuel.  
     
     
         8 . A fuel cell assembly in accordance with  claim 1  wherein said assembly is mounted on a vehicle.  
     
     
         9 . A fuel cell assembly in accordance with  claim 1  wherein said assembly is mounted stationary.  
     
     
         10 . A fuel cell assembly in accordance with  claim 8  wherein said vehicle is selected from the group consisting of car, truck, boat, and airplane.  
     
     
         11 . A fuel cell assembly in accordance with  claim 10  wherein said assembly is an auxiliary power unit for said vehicle.  
     
     
         12 . A fuel cell assembly in accordance with  claim 1  wherein said fuel cell is a solid-oxide fuel cell.  
     
     
         13 . An automotive vehicle, comprising a fuel cell assembly for generating auxiliary power for said vehicle, the assembly including 
 nickel-containing anodes,    passageways leading to and from said anodes for conducting fuel to and from said anodes, and    oxygen getter means disposed in each of said passageways for preventing gaseous oxygen from reaching and oxidizing said nickel in said anodes.