Effects of Lithium Sulfate and Zinc Sulfate Additives on the Cycle Life and Efficiency of Lead Acid Batteries

Abstract

The influence of lithium and zinc sulfate additives on the cycle life and efficiency of a 2 V/20 A H lead acid battery was investigated. Charging and discharging processes (cycle) were carried out separately for dilute sulfuric acid electrolyte, sulfuric acid-lithium sulfate electrolyte, and sulfuric acid-zinc sulfate electrolyte solutions for one (1) hour each. The voltage after 30 min of the charging process yielded 2.30 V for dilute H2SO4, 2.74 V for H2SO4 + Li2SO4, and 2.90 V for H2SO4 + ZnSO4 solutions. A load of 6 V, 10.3 W incandescent lamp was applied, and after 30 min of the discharge process for each electrolyte, the voltage was 1.10 V for H2SO4, 1.90 V for H2SO4 + ZnSO4, and 1.30 V for H2SO4 + Li2SO4. A calculated efficiency of 77% for H2SO4, 74% for H2SO4 + ZnSO4, and 85% for H2SO4 + Li2SO4 solution was obtained. The cycle test is evidence that the addition of lithium sulfate salt improved the cycle life and efficiency of the 2 V/20 A H lead acid battery, while zinc sulfate offered no significant improvement. The cycle life of a battery increases with decrease in acid concentration, longer discharge time, and increase in efficiency.