Multi-functional hermetic seal for non-aqueous electrochemical cells

#1. Field of the Invention

#The present invention relates to the field of non-aqueous electrochemical cells which contain highly corrosive chemical components and so require hermetic sealing. More particularly, the invention concerns improvement in the hermetic seals of such cells which reduces corrosion and allows the electrical connector bridging the seal or pin terminal to be either positive or negative.

#2. Description of the Prior Art

#Reference is hereby made to the drawings in which:

#FIG. 1 is a schematic view, in section, of a prior art seal of the class described,

#FIG. 2 is a schematic top view showing the preferred embodiment of the present invention; and

#The header device of the prior art device of U.S. Pat. No. 4,358,514 is shown generally in FIG. 1. That invention accomplished the forming of an hermetic seal between the header, the terminal pin and the body of an electrical chemical cell. The stainless steel header 11 is sized to hermetically fit the body of a cell, whereby welding or other hermetically bonding can be accomplished in a conventional manner. An annular glass ring 12 is fitted inside and bonded to the stainless steel header 11. A pin terminal which consists of a central nickel core 13, and a stainless steel sleeve 14 is fitted within the annular glass ring 12. High temperature nickel brazing 15 is applied to keep the thin outer shell 14 solidly bonded to the nickel core 13.

#The temperatures of fabrication, which may range from at least 1800.degree. F. to in excess of 2000.degree. F. The brazing 15 further prevents circumferential growth of the sleeve 14. The nickel braze 15 also provides a low resistance electrical contact through the seal to the terminal pin. By making the sleeve 14 slightly longer than the nickel core 13, subsequent trimming of the sleeve and welding of the enclosures into the inside diameter of the sleeve can be accomplished. The glass 12 and the nickel core 13 have relatively closely matched coefficients of expansion, particularly when compared to the coefficient of expansion of the stainless steel.

#Now, the cell sealing structure contemplated by the present invention, will be described with respect to FIGS. 2 and 3. The conventional stainless steel torus-shaped header is depicted, in part, at 20 (FIG. 3). Of course, this header is sized to hermetically fit the body of the cell, normally also stainless steel, for which it is designed and can be bonded thereto in any compatible conventional manner such as by welding. Concentrically, inside the header is a glass ring 21 which is typically made of an aluminoborate glass such as Fusite #425 glass manufactured by Fusite Corporation of Cincinnati, Ohio. The terminal pin of the invention is located inside the glass ring 21 and is made up of a composite structure including an outer case surrounding and increasing the lower portion of a solid central pin member 23 and fixed thereto as by high temperature brazing at 24 to present a solid unit with regard to the integrity of the opening in the glass ring 21.