Patent GB-610719-A (GB)
Title: Alkaline dry cell
IPC: H01M4/36
Filed: 1945-10-08
Abstract: 610,719. Batteries. MALLORY & CO., Inc., P. R., and TRIGGS, W. W. Oct. 8, 1945, No. 26188. [Class 53] A dry cell has an air-tight container and an alkaline electrolyte having dissolved in it a quantity of zincate sufficient to inhibit on opencircuit any reaction between the electrolyte and anode. Fig. 1 shows a cell in which a depolarizer 31 is placed in a steel container 30 and covered by a porous disc 32 supporting an anode consisting of a roll of amalgamated zinc foil wound with an intervening sheet of filter paper and enclosed in an insulating sleeve. The top of the zinc projects above the roll and makes contact with an amalgamated zinc disc 37 which is separated from the container 30 by an insulating grommet 38. The disc 37 or a wire 42 attached thereto forms the negative pole, the container forming the positive pole. The top of the disc 37 may be coated with lacquer to assist in excluding air from the cell. The anode roll is dipped in a solution of potassium hydrate containing a zincate before being inserted in the cell. The separator 32 may consist of a porous disc of magnesium silicate or hydroxide, ceramic, glass, asbestos, &c. or regenerated sheet cellulose, synthetic resin &c. The depolarizer may consist of oxide of mercury, silver, copper or lead or a permanganate of potassium, calcium, silver, copper or lead, and may be mixed with finely-divided graphite, the mixture being pressed into pellet form. A flat form of cell is also described in which the steel container is dish-shaped and the zinc electrode consists of a number of perforated zinc discs as shown in Fig. 5. The discs are connected together and folded over one another with blotting paper between adjacent discs. Mercury cyanide may be added to the electrolyte to amalgamate the zinc. In another modification the anode consists of compressed zinc powder. Flat cells may be stacked in a steel can to form a battery. Fig. 11 shows a cylindrical form of cell in which a steel container encloses depolarizing material in the form of a cylinder 431 which is covered with layers of a polyvinyl alcohol film 432 and porous paper 435. Instead of paper a spacer of compressed magnesium hydroxide and silicate or of polystyrene fibres or ceramic material may be used. The anode 434 is a cylinder of porous amalgamated zinc powder within which is a roll 448 of porous polystyrene fibre or paper. Electrolyte is poured on to the roll 448 and percolates to all parts of the cell. The cell is closed by a zinc top 437 which makes contact with the anode 434. Another modification comprises a steel container lined on its sides with insulating material and enclosing a roll consisting of corrugated zinc foil, sheets of porous paper and of plasticized polyvinyl alcohol, and a steel strip coated with a depolarizer and binder. The zinc projects at the upper end of the roll and makes contact with a zinc closure, the cathode projecting at the bottom and making contact with a steel support resting on the bottom of the container. Fig. 15 shows a further modification in which a pressed powdered zinc anode 634 makes contact with a zinc plate 637 having a shank 627 moulded into an insulating container 630. A paper roll 645 impregnated with electrolyte and a porous organic film 632 separate the zinc from the depolarizer 631 which is compressed into a steel cup 620 forming the positive pole of the cell. An anode in the form of a roll may be made by spraying zinc on one side of a strip of paper, cloth, regenerated cellulose, &c., rolling the coated strip and enclosing it in an insulating sleeve.