Continuous electroforming process to form a strip for battery electrodes and a mandrel to be used in said electroforming process

Abstract

A continuous electroforming process to form a strip for battery electrodes, comprising the steps of providing a mandrel having on its surface a reusable pattern subdivided into conductive and non-conductive areas; moving said mandrel through an electroforming bath to deposit a metal layer on said mandrel while it moves through the electroforming bath until the metal layer has assumed the shape of the conductive pattern and a thickness at least sufficient to provide strength for the layer to be removed from said mandrel; and separating said layer from said mandrel; is characterised by moving said strip through at least one subsequent bath in which electrodeposition of metal takes place on both sides of said strip while it is moved through said subsequent bath, applying a current density of at least 10 A/dm2 and up to 300 A/dm2 to the conductive surface of the moving mandrel and to the metal surface of the strip in each of the subsequent baths; and directing a forced flow of electrolyte onto the surface of the layer and said strip, wherein the reusable conductive pattern of the surface of the mandrel takes the form of at least one battery electrode and the electrolyte contains additives providing increased hardness, increased corrosion resistance and being suited specifically to permit combining a high rate of deposition with controlled surface roughness and controlled composition of the deposit.