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 nickel, silicon, boron, and an active metal element. The braze alloy includes nickel in an amount greater than about 50 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.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application relates to, and claims priority from, the provisionally filed U.S. patent application having Ser. No. 61 / 651,817, entitled “COMPOSITIONS FOR BRAZING, AND RELATED METHODS AND DEVICES”, filed on May 25, 2012, which application is hereby incorporated by reference.TECHNICAL FIELD[0002]This invention generally relates to a braze composition. In some specific embodiments, the invention relates to a braze composition that provides corrosion-resistant sealing and other benefits to high temperature rechargeable batteries.BACKGROUND OF THE INVENTION[0003]Many types of seal materials have been considered for use in high-temperature rechargeable batteries / cells for joining different components. Sodium / sulfur or sodium / metal halide cells generally include several ceramic and metal components. The ceramic components include an electrically insulating alpha-alumina collar and an ion-conductive electrolyte beta-alumina tube, and are gene...

AI Technical Summary

Benefits of technology

[0007]It may be desirable to develop new braze alloy compositions that have properties and characteristics that meet performance requirements for high temperature rechargeable batteries, and are less complicated and less expensive to process, as compared to the existing sealing methods.

[0008]Various embodiments of the present invention may provide braze alloy compositions for sealing a ceramic to a metal, to form a seal that can withstand corrosive environments.

Problems solved by technology

However, metal-to-ceramic bonding can sometimes present some difficulty, mainly due to thermal stress caused by a mismatch in the coefficient of thermal expansion for the ceramic and metal components.

However, most of the seals may not be able to withstand high temperatures and corrosive environments.

In short, the method is relatively expensive, and complicated, in view of the multiple processing steps, and the difficulty in controlling the processing steps.

However, most of the brazing materials (or braze materials) have limitations that prevent them from fulfilling all of the necessary requirements of high temperature batteries.

Moreover, some of the commercial braze materials can be quite expensive themselves; and using them efficiently in various processes can also be costly.

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