GB232802A - Improvements in or relating to electric batteries - Google Patents

Abstract

232,802. James, R. W., (Manhattan Electrical Supply Co., Inc.). May 27, 1924. Absorbents; electrodes; electrolytes.-In a dry cell of LeclanchÚ type the depolarizer is in the form of tablets 1 with a central perforation 3 through which the carbon electrode 7 passes, the tablets having bevelled edges and'grooves 2, 4 to form channels for distribution of water or electrolyte. The carbon electrode may be hollow, with perforations 9 preferably registering with the grooves 2, the upper end through which water or electrolyte is introduced having a stopper 11. The lower end may also be closed, and the electrode may contain absorbent material. Alternatively, the electrode may be solid with a surface groove, or with corrugations, in which case the apertures 3 in the tablets may be correspondingly corrugated to fit the electrode. The tablets contain manganese dioxide and graphite in impalpable and flaked form. The impalpable graphite used is treated with hydrochloric, sulphuric, or nitric acid preferably with permanganate or other oxidizing agent, and then with alkali, to remove impurities. The flaked graphite is produced artificially by mixing powdered graphite with chloride of zinc, ammonium, calcium, or sodium in solution or dry, and compressing. Weak organic acids or other materials may be added as binders. The material of the tablets is preferably graded as regards fineness in concentric rings 25, 26, 27, Fig. 2, the outer ring 25 being the most porous. A lining 10 of paper coated with paste may be placed within the zinc electrode container 6, but preferably, the tablets are coated with bibulous material by dipping or spraying, the material described being a mixture of wood pulp, plaster of paris, coarsely granulated manganese dioxide, diatomaceous earth and the like, with flour, starch, &c. zinc chloride or other electrolyte, and water.