Effect of chlorine-containing species on lead/acid battery posts

Chloride in the electrolyte of lead/acid batteries has long been thought to cause early failure due to accelerated corrosion of the positive-plate group. This study investigates the effect of chloride species, added as either hydrochloric acid or sodium chloride, on positive posts of lead/acid cells under float conditions. The introduction of chloride from either source results in higher float currents and enhanced corrosive attack of the positive post above the electrolyte level. The presence of sodium chloride also promotes an additional and distinctive form of corrosion. Given these findings, a review of maximum chloride levels in industry standards for both battery acid and makeup water is indicated.