GB662774A - Improvements in the manufacture of electric dry cells - Google Patents

Abstract

662,774. Primary batteries. BURNDEPT, Ltd., JONES, K., and GLATSTER, S. B. Jan. 24, 1950 [Jan. 26, 1949], No. 2158/49. Class 53. The anode of a dry cell consists of an agglomerate of paper pulp fibre, a gelling agent, and a finely-divided metal, for example zinc. In a method of manufacturing the anode a rag or sulphite wood pulp is stirred in water containing starch which is heated to form a viscous suspension. Zinc dust is then added and the mixture stirred until a uniform suspension of the metal and pulp is obtained. This is then moulded into cylindrical form in a filter press comprising a cylindrical mould chamber lined with wire gauze and enclosing a centrallydisposed mandrel. Openings in the bottom of the mould allow water and gel pressed out of the suspension to flow away. Above the mould is a charging cylinder fitted with a piston. The charging cylinder is filled with a measured quantity of the suspension which is forced by the piston into the annular space between the mould and enclosed mandrel. The mandrel and wire gauze are removed with the moulded anode which is then dried. A cylindrical anode may alternatively be made by making the suspension into a sheet and wrapping it round a mandrel. A thin sheet of the suspension may be wrapped several times round the depolarizer with which it is to be used. In a battery of the layer type the suspension may be made into flat form with a metal sheet beside it to serve as a current collector. Instead of starch other gelling agents may be used such as cellulose acetate, pyroxylin, casein, sodium alginate and gums. The anode may be used in a cell employing an electrolyte of caustic potash and a depolarizer of mercuric oxide. Into whatever shape the anode is formed the pulp fibres run generally parallel to its surface.