Influence of Carbon and Interaction of Carbon and Lignosulfonate on Dynamic Charge Acceptance of Flooded (Enhanced) Lead Acid Batteries

Lead acid batteries are being developed to suit automotive micro hybrid (stop-start) applications that demands, cycling continuously at high rate of discharge and charge in partial state of charge (HRPSoC) mode. High rate of discharge is necessary for engine cranking and acceleration, while high rate charge associated with regenerative braking. In Lead acid, enhanced flooded battery is a cost effective solution for above such vehicles. Various studies reported that, flooded lead acid batteries operated in HRPSoC mode loses capacity on cycling, because of sulfation of negative plates. In order to suppress this process, the rate of charge process or the dynamic charge acceptance (DCAT) during PSoC cycling need to be enhanced. Numerous studies reported the improvement on DCAT and its impact of improved cycle life using increased level of carbon in negative active material and also with high surface area carbon materials [1]. In this study, we have used conventional carbon black and high surface area carbon at different levels along with varied level of ligno-sulfonate to understand the impact comprehensively on dynamic charge acceptance and high rate discharge performance. Results show that increase in carbon and high surface area carbon improves the dynamic charge acceptance, however the level of ligno-sulfonate also influences this performance. Increase in the ligno-sulfonate addition affects the high surface area carbon influence and hence affects the charge acceptance also. This indicates that the ratio of carbon to lignosulfonate need to be adjusted and extent of high surface area carbon addition to be made very carefully by assessing the other impacts on battery performance.