Improvements in and relating to the production of electric batteries

833,050. Batteries. BURNDEPT Ltd. Aug. 1, 1958 [May 1, 1957], No. 13925/57. Class 53. A cell consisting of a metal electrode 5, a sheet of absorbent paper 4, and a depolarizer 3 is provided with a casing by placing the elements of the cell on a plastic sheet 1 and applying a covering 6 of plastic material in liquid form or as a sheet or ribbon sufficiently plasticized to sink over the edges of the elements and adhere to the sheet 1. A gas space 8 is left in the cell. A continuous method of providing cases for a number of cells consists in passing the plastic sheet beneath punches to make holes 2 above which the cell elements are placed. The sheet is then passed under, a nozzle which sprays plastic material over the cells and the adjacent parts of the sheet 1. The electrode 5 is exposed through an opening made in the plastic by a tube bevelled at its lower end. Fig. 3 shows'an alternative method in which a viscous plastic issues from a hopper 9 between rollers which spread the plastic into a sheet or ribbon which covers the cells and adheres to the sheet 1 which may be heated or treated with a solvent to form a weld with the plastic covering. Apertures are made in the cover to expose the metal electrode, and these apertures and the holes 2 may be filled with a conductive plastic. The whole of the sheet 1 may be made of conductive plastic, in which case the holes 2 may be dispensed with. The spraying process may be performed with the use of a static electric field whereby the material to be sprayed is flung off the edge of a rotating disc which is kept at a high potential. Specification 798,452 is referred to.