GB1398491A - Battery casing and sealed primary sodium-halogen battery - Google Patents

Abstract

1398491 Sodium-halogen battery GENERAL ELECTRIC CO 15 Feb 1973 [1 March 1972] 7420/73 Heading H1B A battery casing for a sealed primary sodiumhalogen battery comprises an open-ended inner casing 11 of solid sodium-ion-conducting material, e.g. of sodium beta-alumina, an outer open-ended casing 14 surrounding the inner casing and also having an opening 16 therein, a cover 20 with a central opening 21 therein sealed to the upper open ends of both casings 11 and 14 and fill tubes 18, 22 associated with respective openings 16, 21 in the outer casing and cover and an electronic conductor 13 within the casing 11 and affixed to the fill tube 22. The outer casing is .preferably metallic, e.g. of niobium or tantalum, and the cover 20 may be made of a metal, e.g. nickel, Kovar (Registered Trade Mark) alloy, niobium or tantalum, of a sodium and halogen resistant glass or of alpha-alumina or beta-alumina. The cover 20 is sealed to the open ends of both casings by a sodium and halogen resistant glass washer 23. The anode 24 is disposed in the inner casing 11 and comprises sodium metal either alone, in an amalgam or in a non-aqueous electrolyte, e.g. a sodium halide salt in propylene carbonate. After casing 11 has been filled with the anode material the fill tube 22 is closed and sealed by welding as at 26. The cathode 25 comprises a halogen, e.g. bromine which may be mixed with 5-60% by weight iodine, in conductive material such as a porous matrix of carbon felt or foam metal, an aqueous electrolyte, a non-aqueous electrolyte such as sodium halide salts in propylene carbonate and with dissolved small amounts of additives such as NaCl, NaBr, KCl, AlCl 3 , AlBr 3 or POCl 3 . After filling the outer casing with the cathode the metallic fill tube 18 is sealed as by welding at 27. The conductor 13, e.g. of nickel, Kovar (Registered Trade Mark) alloy, niobium or tantalum, is welded to the fill tube 22.