GB189811640A - Improvements in Accumulators or Secondary Batteries, and Apparatus for their Manufacture. - Google Patents

Abstract

11,640. Heimel, F. May 23. Secondary batteries.-Positive plates are made by fitting a lead tray into the underside of a frame n, Fig. 2, and then forcing this tray into a mass of active material on the rotary web e, Fig. 1. This active material has been formed into a layer of uniform thickness on its passage from the hopper h between the rollers b, f, the latter of which is covered with a loose web g. The frame n is carried along by the web e, and its guide-rollers m finally engage with parallel curved rails i, so that, when the tray reaches the rotary web l, it is reversed in position and may be taken out of the frame n. Two such trays filled with active material are placed face to face with their flanged edges in contact, and are held together by clamps or by slit tubes of acid-resisting material fitted over the flanges of the trays. The electrode is then perforated, preferably with blunt punches so as to leave a burr at the edge of the perforations. The negative electrodes may be similarly made of lead foil, and a group of electrodes with interposed grids of celluloid, glass, &c. are held together by springs, which may be of steel coated with lead. To prevent splashing, the cells may be provided with a loose cover which floats on the electrolyte. Fig. 10 shows in vertical section a form of cell in which the negative electrode consists of a zinc plate w or a layer of zinc amalgam which is in contact with a conducting-strip v through a hole in the cell which is filled with mercury or zinc amalgam and covered on the outer side by the strip v. A grid x of acidproof material is placed on the zinc w, and on this is placed a sheet of asbestos paper, silk, &c. on which the positive electrode y is then placed and covered by a grid z of acidproof material. The electrolyte employed is a mixture of dilute sulphuric acid, zinc sulphate, and magnesium sulphate.