Patent GB-491782-A (GB)
Title: Improvements in accumulators
IPC: H01M50/627
Filed: 1937-02-04
Abstract: 491,782. Batteries. ANDRE, H. G. Feb. 4, 1937, No. 3387. Convention date, Sept. 23, 1936. [A Specification was laid open to inspection under Sect. 91 of the Acts, Aug. 5, 1937.] [Classes 38 (i) and 53] An accumulator comprises a negative electrode on which zinc or other metal soluble in the electrolyte is deposited during charging, a separator of a cellulosic material between the negative and positive electrodes, and retaining means such as wire gauze between the separator and negative electrode to receive and retain metal deposited on the negative electrode and provide room for the latter to expand. Fig. 2 shows a part of an accumulator in which the negative electrode consists of a zinc sheet 110 surrounded by powdered zinc 111, the positive electrode consisting of copper or silver mesh 1 surrounded by finely divided silver 102. The latter is enclosed in a cellulosic envelope 3 which may be covered by a second perforated cellulosic envelope 107a. Between the positive and negative electrodes is a retaining mesh or gauze 108 adapted to support zinc deposited from the electrolyte. The lower ends of the electrodes and the positive connections may be embedded in paraffin wax 105. Layers of glass threads may be placed between the gauze 108 and cellulosic separators. Fig. 5 shows an accumulator having electrodes as described above and in which the negative electrodes are connected to the metal container at 116. The container is silvered internally, and the electrolyte consists of potash solution. The insulating material 105 rests on a rubber disc 117.and the positive lead is surrounded by an insulating sleeve 115. The positive terminal is surrounded by two hollow rubber members 119, 120, the former of which protects the terminal from particles of zinc when the accumulator is inverted. The negative terminal 126 is soldered to the accumulator lid. A metal stirrup 131 soldered to the lid indicates the correct level of the electrolyte and is insulated from the electrodes by a rubber strip 134. The gas exit and closure plug comprise a tube 136 closed at the upper end by a piece of rubber tubing 138 carrying a spongy mass 145 to absorb liquid. A glass tube 141 carries a perforated rubber cap 140. The Specification as open to inspection under Sect. 91 describes an accumulator in which the positive electrode consists of a number of silver plates 1, Fig. 2 (Cancelled), covered with finely divided silver agglomerated with potash and seaweed. The plates are joined by wires 2 and wrapped in a cellulosic covering 3, the band so formed being then folded in zigzag fashion as shown in Fig. 3 (Cancelled). The negative electrodes 6 are placed in the folds of the positive electrode and consists of silver covered with zinc. The electrolyte is a solution of potassium carbonate and lithia. The negative electrodes are given an initial coating of zinc by electrodeposition. A gas exit consists of a tube 9 into which is screwed a member 10 which presses on a rubber diaphragm 12 having a central aperture. A perforated brass disc may be placed between the diaphragm 12 and member 10. The upper part of the tube 9 is filled with layers of asbestos 13. The space above the electrodes is sufficient to receive all the electrolyte when the cell is inverted. The positive terminal consists of a rod 17 to the lower end of which the positive lead 20 is soldered. The rod 17 passes through insulating members 15, 16, a recess in the lower part of the member 15 being filled with pitch. The negative plates 6 may be in the form of gratings or of zinc sheet surrounded by silver wire or of coiled or twisted wires. This subjectmatter does not appear in the Specification as accepted.