SEPARATOR FLEECE FOR MAINTENANCE-FREE LEAD ACCUMULATORS WITH FIXED ELECTROLYTE

摘要

The undesired acid stratification in lead accumulators whose electrolyte is held in fleece separators, preferably glass fleeces, can be avoided by artificially increasing the flow resistance within the fleece, without preventing ion movement. This is achieved by soaking the fleece before incorporation with an approximately 3% colloidal silicic acid and subsequently drying it, the SiO2 deposited on the fibres resulting in the weight of the fleece increasing by approximately 20% and its inner surface area increasing from approximately 1 m2/g to approximately 50 m2/g. The SiO2 particles suitable for producing the colloidal silicic acid have BET surface areas between 100 m2/g and 300 m2/g with a diameter of approximately 15 nm (15 x 107 cm).