Patent GB-596523-A (GB)
Title: Improvements in or relating to electric dry batteries
IPC: H01M6/38
Filed: 1945-07-28
Abstract: 596,523. Galvanic batteries. BURGESS BATTERY CO. July 28, 1945, No. 19362. Convention date, Sept. 20, 1944. [Class 53] A battery comprises a number of cells joined in series and enclosed in an outer container, the electrolyte being introduced into the cells when the battery is required for use. Each cell is provided with an opening communicating with the interior of the container and the electrolyte is contained in a frangible capsule within the container or is introduced into the container through a filling opening. In order to prevent short-circuiting of the cells by unabsorbed electrolyte, the latter is displaced from the vicinity of the cell openings by the introduction into the container of a non-conducting liquid which will not mix with the electrolyte and which is heavier than the electrolyte if the openings are in the lower ends of the cells. If the electrolyte is introduced into the upper ends of the cells alight non-conducting liquid is floated on the surface of the electrolyte. The non-conducting liquid may be contained in a separate frangible capsule which is broken some time after the electrolyte has been freed from its capsule or it may be introduced through the filling opening of the container. In an alternative method of introducing the non-conducting liquid it is contained in a capsule made of gelatine or other substance soluble in water. The cells may comprise bipolar electrodes dividing the container into a number of compartments or separate cylindrical cells may be used. The anodes may consist of zinc, magnesium, aluminium or calcium and the cathodes of carbon, copper, gold, silver or platinum. Depolarizers may be used such as manganese dioxide, copper oxide, lead oxide, silver chloride or bromide and the electrolyte may consist of a solution of zinc chloride or ammonium chloride. Solid ammonium or zinc chloride may be incorporated in the absorbent material in each cell in which case only water need be added to activate the battery. Suitable non-conducting liquids heavier than water are carbon tetrachloride, chloroform, ethyl iodide, propyl iodide, butyl iodide and tribromoethane. Lighter liquids for floating on the electrolyte may be kerosene, benzol, toluene and other hydrocarbons, amyl alcohol and amyl acetate. Fig. 1 shows a container 10 enclosing a number of cells 12 and two capsules containing electrolyte or water 37 and a heavy non-conducting liquid 38. Each cell comprises a carbon electrode 25 surrounded by depolarizer 24 and absorbent material 22 such as blotting paper. A zinc cup 16 is formed with an opening 17 at the bottom which is covered by the insulating liquid after the electrolyte has been absorbed in the material 22, any unabsorbed electrolyte floating on the non-conducting liquid as shown at 48. The capsules are broken in succession by striking the bottom of the container against a suitable surface, a pointed member 33 facilitating breakage of the capsules. Fig. 6 shows a modification in which bipolar electrodes are employed embedded at their sides and lower ends in sealing material 128, thus forming a number of cells open at the top. Capsules are enclosed in compartments at the ends of the container formed by insulating partitions 111, 115 and are broken by spring plungers 134, 135. The final level of the electrolyte is shown at 141 and the non-conducting liquid floats on the surface of the electrolyte as shown at 142. In another modification bipolar electrodes are sealed into the lid of the container and spaced from the bottom, the capsules being contained in a central space in the container, the non- conducting liquid being heavier than the electrolyte.