Braze compositions, and related devices

Abstract

A braze alloy composition for sealing a ceramic component to a metal component in an electrochemical cell is presented. The braze alloy composition includes copper, nickel, and an active metal element. The braze alloy includes nickel in an amount less than about 30 weight percent, and the active metal element in an amount less than about 10 weight percent. An electrochemical cell using the braze alloy for sealing a ceramic component to a metal component in the cell is also provided.

1 . An electrochemical cell comprising:
 a tubular separator disposed in a cell case defining a portion of a cathodic chamber and an anodic chamber, wherein the cathodic chamber comprises an alkali metal halide, and forms an ion capable of conducting through the separator;   an electrically insulating ceramic collar disposed on a top end of the separator, and   a metal ring disposed on the electrically insulating ceramic collar,   wherein the electrically insulating ceramic collar is joined to the metal ring by a braze alloy composition comprising nickel, chromium, iron, silicon, boron and an active metal element, wherein chromium is present in an amount less than 10 weight percent, iron is present in an amount less than 10 weight percent, silicon is present in an amount from about 2 weight percent to about 10 weight percent, boron is present in an amount less than 5 weight percent, the active metal element is present in an amount from about 1 weight percent to about 3 weight percent, based on a total weight of the braze alloy composition, wherein the active metal element comprises titanium, zirconium, hafnium, vanadium, or a combination thereof, and wherein the braze alloy composition is in direct contact with both the electrically insulating ceramic collar and the metal ring.   
     
     
         2 . The electrochemical cell of  claim 1 , wherein the alkali metal halide comprises sodium halide. 
     
     
         3 . The electrochemical cell of  claim 1 , wherein the anodic chamber contains sodium. 
     
     
         4 . The electrochemical cell of  claim 1 , wherein the braze alloy composition comprises from about 2 weight percent to about 5 weight percent of silicon. 
     
     
         5 . The electrochemical cell of  claim 1 , wherein the active metal element comprises titanium. 
     
     
         6 . The electrochemical cell of  claim 1 , wherein the braze alloy composition has a liquidus temperature in a range from about 850 degrees Celsius to about 1250 degrees Celsius. 
     
     
         7 . The electrochemical cell of  claim 1 , wherein the metal ring comprises nickel. 
     
     
         8 . The electrochemical cell of  claim 1 , wherein the electrically insulating ceramic collar comprises alumina. 
     
     
         9 . The electrochemical cell of  claim 1 , wherein the braze alloy composition comprises an active braze seal that joins the metal ring to the electrically insulating ceramic collar. 
     
     
         10 . The electrochemical cell of  claim 9 , wherein the active braze seal comprises a thin reaction layer at an interface of the electrically insulating ceramic collar and the braze alloy composition. 
     
     
         11 . An energy storage device comprising a plurality of electrochemical cells as defined in  claim 1 .