Development of advanced lead acid batteries for electric vehicles the use of additives to increase performance and extend life

Trojan Battery Company and Ensci Incorporated, have completed a program which evaluated the use of additives to improve the specific energy and ultimately the life of lead acid batteries. The increase in specific energy has been achieved through the use of additives incorporated into the positive active material. The additives allow higher active material utilization efficiency which manifests itself in increased discharge capacity, extended vehicle range, enhanced power capability, faster recharge, longer life and lower battery manufacturing costs. This performance improvement ranges from 10-280% depending on the rate of discharge. It has been suggested in many publications that batteries with antimony containing positive grids have longer life. It is well known that antimony from the positive grid will be liberated by corrosion mechanisms and eventually deposited on the negative active material. Once deposited on the negative, antimony has the undesirable effect of increased self-discharge, hydrogen evolution and water loss. Antimony deactivating additives have been incorporated into the negative active material to minimize or eliminate these adverse effects. We have shown that these additives are altering the negative electrode behavior significantly, indicating that antimony deposition on the negative electrode is being hindered.