TECHNIQUES TO REDUCE FAILURE IN LEAD CALCIUM BATTERIES USING EXPANDED TYPE GRIDS

Recent developments have improved the following characteristics of lead/acid batteries that employ expanded lead-calcium grids: (i) recovery after overdischarging and long standing; (ii) battery life at high temperature; (iii) battery life under deep-cycling conditions. It is widely known that the addition of tin to Pb-Ca-Sn alloys is effective in assisting recovery after overdischarging and long standing. It has also been found that the surface-treatment technology developed to make a Pb-Sn alloy thin layer on the expanded Pb-Ca-Sn wrought alloy grid has improved these characteristics. Since the temperature of engine compartments in Japanese automobiles has risen in recent times, the life of batteries subjected to these temperatures has become increasingly important. Through combination of surface treatment with a thin Pb-Sb-Sn alloy layer, and increases in the corrosion resistance and mechanical strength of Pb-Ca-Sn wrought alloys, the life of automotive batteries at high temperatures has been extended remarkably. Such an approach has also improved the life of batteries used in deep-cycling conditions.