GB1132897A - Improved primary cell - Google Patents

Abstract

1,132,897. Primary cells. DOW CHEMICAL CO. 26 May, 1966 [1 June, 1965], No. 23581/66. Heading H1B. A primary cell 10 comprises a carbonaceous cup as the cathode electrode 12 with a closed end 14 and open end 16, a Mg or Mg alloy anode assembly 20 which is adapted to change its configuration during operation of the cell and which is disposed within but spaced apart from the cup, and a cathode mix 34 which is electrically coupled to and disposed between the anode and cathode, but which is physically separated from the anode. The cup 12 is composed of carbonaceous particles mixed with a synthetic plastics binder material, and the anode assembly comprises an anode 20 composed of sheet Mg alloy rolled to form a tube with overlapping edges and is covered over at least the part of its length which is exposed to the cathode mix 22 by a paper tube or bobbin 24, an insulated wire 30 being fixed to the upper end 32 of the anode. A pair of insulating wafers 36, 38, usually paper, extend across the cup 12 above the anode 20, and above these is a wax seal 40. A metal wafer 44 having a protuberance 46 fits into the lower part of an insulating sleeve 42 surrounding cup 12. The cathode mix is preferably a mixture of MnO 2 and C black moistened with an electrolyte and moulded into a cake. The electrolyte is preferably an aqueous solution of ammonium or an alkali or alkaline earth metal bromide and a corresponding salt of chromic acid. In further embodiments the anode may contain a compressible material disposed therein, or it may be formed of two Mg plate elements or of a U-shaped sheet of Mg alloy having a layer of compressible material disposed or sandwiched therebetween.