PURPOSE: To eliminate generation of syneresis and obtain a leakage free lead- acid battery by mixing silica fine powder in positive active material of a clad type lead-acid battery using gelled electrolyte.

CONSTITUTION: Silica fine powder is mixed in positive active material of a lead- acid battery in which gelled electrolyte formed with silica and dilute sulfuric acid is used and clad type plate is used as a positive plate. For example, 8wt% of silica powder is added to 1kg of lead powder with an oxidation degree of 70%, and they are filled in a tube to prepare a clad type plate. Dilute sulfuric acid with a specific gravity of 1.28 containing 10wt% of silica is poured to form a lead-acid battery. Since free dilute sulfuric acid is absorbed by silica powder existing in fine pores of active material, generation of syneresis is prevented.