The influence of different negative expanders on the performance of VRLA batteries

The behaviour of different novel expander additives and negative plate formulations has been investigated in cylindrical VRLA batteries under different electric (EV) and hybrid (HEV) vehicle service conditions, using negative active mass (NAM) compositions previously optimised in 2 V VRLA cells. The most interesting results are related to the cycling behaviour under both EV and HEV specifications, where up to 900 cycles and more than 180,000 cycles have been achieved, respectively, depending on the NAM additive used. Other interesting battery characteristics, such as charge acceptance at low temperatures, have been also improved by introducing an appropriate NAM formulation.