Electrochemical stack assembly for ceramic oxygen purification

Abstract

Systems for oxygen concentration and pressurization. An assembly includes an electrochemical stack comprising: a plurality of wafers, wherein the plurality of wafers comprises a first ceramic wafer and a second ceramic wafer; a ceramic spacer disposed in between the first ceramic wafer and the second ceramic wafer; and an interconnect disposed in between the first ceramic wafer and the second ceramic wafer that facilitates electrical communication between the first ceramic wafer and the second ceramic wafer. The assembly includes a metal tube for porting the purified oxygen gas output by the electrochemical stack. The assembly includes a terminal plumbing assembly that couples the electrochemical stack to the metal tube, wherein the terminal plumbing assembly comprises a ceramic adapter, a metal adapter, and an adapter skirt, and wherein the adapter skirt extends outward relative to a sidewall of the metal adapter.

What is claimed is: 
     
         1 . A stack assembly for outputting purified oxygen gas, the stack assembly comprising:
 an electrochemical stack comprising:
 a plurality of wafers, wherein the plurality of wafers comprises a first ceramic wafer and a second ceramic wafer; 
 a ceramic spacer disposed in between the first ceramic wafer and the second ceramic wafer; and 
 an interconnect disposed in between the first ceramic wafer and the second ceramic wafer that facilitates electrical communication between the first ceramic wafer and the second ceramic wafer; and 
   a metal tube for porting the purified oxygen gas output by the electrochemical stack; and   a terminal plumbing assembly that couples the electrochemical stack to the metal tube, wherein the terminal plumbing assembly comprises a ceramic adapter, a metal adapter, and an adapter skirt, and wherein the adapter skirt extends outward relative to a sidewall of the metal adapter.   
     
     
         2 . The assembly of  claim 1 , wherein the terminal plumbing assembly comprises:
 the ceramic adapter, wherein at least a portion of the ceramic adapter comprises a frustrum geometry;   the metal adapter comprising the sidewall, wherein the sidewall defines a hollow cylindrical geometry; and   the adapter skirt attached to the metal adapter;   wherein the adapter skirt receives the ceramic adapter; and   wherein a sealant is disposed in between an exterior surface of the ceramic adapter and an interior surface of the adapter skirt.   
     
     
         3 . The assembly of  claim 1 , wherein the ceramic spacer is attached to the first ceramic wafer with a first glass-ceramic seal, and the ceramic spacer is attached to the second ceramic wafer with a second glass-ceramic seal; and
 wherein at least one of the first glass-ceramic seal or the second glass-ceramic seal is a gastight seal after undergoing two or more sintering cycles.   
     
     
         4 . The assembly of  claim 1 , wherein the interconnect is sealed to a porous cathode layer of the first ceramic wafer and is further sealed to an anode cap layer of the second ceramic wafer; and
 wherein the interconnect comprises from about 5 vol. % to about 80 vol. % an electrically conductive metal.   
     
     
         5 . The assembly of  claim 1 , wherein the plurality of wafers of the electrochemical stack output the purified oxygen gas by transporting oxygen ions across at least a portion of the plurality of wafers in response to the electrochemical stack being supplied with an electrical potential. 
     
     
         6 . The assembly of  claim 1 , wherein the interconnect carries current in between the first ceramic wafer and the second ceramic wafer in response to the electrochemical stack being supplied with the electrical potential. 
     
     
         7 . The assembly of  claim 1 , wherein the interconnect comprises a through-porosity that enables an oxygen-containing gas to pass through the interconnect or diffuse into the interconnect. 
     
     
         8 . The assembly of  claim 1 , wherein each of the plurality of wafers of the electrochemical stack comprises:
 an anode cap that is sufficiently nonporous to prevent molecular diffusion across the anode cap;   a porous anode;   an electrolyte that is sufficiently nonporous to prevent molecular diffusion across the electrolyte; and   a porous cathode.   
     
     
         9 . The assembly of  claim 8 , wherein the ceramic spacer is attached to a first electrolyte of the first ceramic wafer and a second anode cap of the second ceramic wafer. 
     
     
         10 . The assembly of  claim 9 , wherein an exposed portion of the ceramic spacer is disposed in between the first ceramic wafer and the second ceramic wafer to define a gap in between the first ceramic wafer and the second ceramic wafer. 
     
     
         11 . The assembly of  claim 1 , wherein each of the first ceramic wafer and the second ceramic wafer comprises a through-hole;
 wherein the ceramic spacer comprises a sidewall defining a hollow cylindrical geometry; and   wherein a first through-hole of the first ceramic wafer is aligned with a second through-hole of the second ceramic wafer, and is further aligned with an internal hole defined by the sidewall of the ceramic spacer to collectively form an exhaust port through the electrochemical stack.   
     
     
         12 . The assembly of  claim 11 , wherein the metal tube is in fluid communication with the electrochemical stack such that the purified oxygen gas is output through the exhaust port of the electrochemical stack and is further output through the metal tube. 
     
     
         13 . The assembly of  claim 1 , wherein the interconnect comprises from about 30 vol. % to about 70 vol. % a ceramic powder. 
     
     
         14 . The assembly of  claim 1 , wherein the interconnect comprises a resistance less than or equal to one ohm. 
     
     
         15 . The assembly of  claim 1 , wherein the terminal plumbing assembly further comprises an adapter skirt attached to the metal adapter, and wherein the adapter skirt comprises a hollow frustrum geometry such that the adapter skirt comprises:
 an upper circular base comprising an upper radius; and   a lower circular base comprising a lower radius;   wherein the lower radius is longer than the upper radius.   
     
     
         16 . The assembly of  claim 15 , wherein the adapter skirt extends outward relative to the sidewall of the metal adapter to define an exterior skirt angle;
 wherein the exterior skirt angle is defined by a first ray running parallel to the sidewall of the metal adapter, and a second ray running parallel to an exterior surface of the adapter skirt; and   wherein the exterior skirt angle is from about 95° to about 170°.   
     
     
         17 . The assembly of  claim 1 , wherein the terminal plumbing assembly comprises a secondary seal disposed on at least a portion of interior surfaces and exterior surfaces of the metal adapter and an adapter skirt that is attached to the metal adapter; and
 wherein the secondary seal comprises a glass seal.   
     
     
         18 . The assembly of  claim 1 , wherein the ceramic spacer is sufficiently nonporous to prevent molecular diffusion through the ceramic spacer. 
     
     
         19 . The assembly of  claim 1 , wherein the ceramic spacer is attached to the first ceramic wafer with a first glass-ceramic seal, and the ceramic spacer is attached to the second ceramic wafer with a second glass-ceramic seal; and
 wherein one or more of the first glass-ceramic seal or the second glass-ceramic seal is a fully devitrified seal.   
     
     
         20 . The assembly of  claim 1 , wherein the ceramic spacer is attached to the first ceramic wafer with a first glass-ceramic seal, and the ceramic spacer is attached to the second ceramic wafer with a second glass-ceramic seal; and
 wherein one or more of the first glass-ceramic seal or the second glass-ceramic seal comprises one or more of lithium oxide, silicon dioxide, aluminum oxide, potassium oxide, boron oxide, or phosphorus pentoxide.