Patent ID: 7682738
Filing Date: 2010-03-23
Classification: H01M,Y02E,Y02P,Y10T

Abstract:
1. A method for producing a lead acid battery that operates on the oxygen cycle, said method comprising the steps of: assembling a cell comprising a pasted, unformed positive plate, a pasted, unformed negative plate, and, between the plates, a sheet of separator material which is an absorbent, porous filtration medium wherein there is free space between at least one of the plates and at least one of the surfaces of the separator, inserting the cell into a case, introducing into the case a mixture of sulfuric acid, of a given, first specific gravity, and silica including at least 10 percent by weight of silica from a never dried precipitated silica slurry, the mixture containing silica in a first, given silica concentration, which is below that which would cause sulfuric acid having the given specific gravity to gel, whereby sulfuric acid is absorbed into the plates and the absorbent, porous filtration medium of the separator material while silica is filtered out of that sulfuric acid, thereby increasing the concentration of silica in sulfuric acid which remains in the free space to a second silica concentration which is higher than the first concentration and is below the concentration which would cause the sulfuric acid in the mixture in the free space to gel, sealing the case, and forming the plate to increase the concentration of the sulfuric acid in the cell to one which, at the second concentration of silica, causes gelation of the sulfuric acid in the free space.