Double integral sliding mode controller for increasing lead–acid battery life in hybrid energy storage systems

Vehicle cranking is associated with high discharge currents, contributing to the shortened lifespan of lead–acid batteries (LABs). One way to address this problem is by combining LAB and supercapacitors, creating a combined battery and supercapacitor energy storage system (HBSCESS) in which the supercapacitor provides some currents during cranking. Different control techniques exist to distribute power between energy storage systems (ESSs) in an HBSCESS configuration. However, non-optimised controllers cannot compensate for complex connections among components of the system and constraint vagueness, which are directly associated with HBSCESSs. This article presents an optimised double integral sliding mode-based genetic algorithm controller (ODISMC-GA) that efficiently distributes the cold cranking current (CCC) between the battery and supercapacitor. The optimisation cost fitness function minimises the difference between the converter output current and voltage with 0.3 % accuracy. This accuracy is compared with a reference range of 0–0.5 % to ensure a small variation in results and improve system efficiency. In addition, the HBSCESS scheme utilises a single-inductor multi-input DC–DC bidirectional converter to interface with the ESSs. The system ensures stability by using the Lyapunov technique. This study evaluated three LABs with 50, 70, and 80 Ah capacities. In addition, it assessed the ability of the HBSCESS system to provide the required cranking current. The respective batteries provided maximum cranking currents of 425, 505, and 710 A for 5 s. The performance analysis considers 20 % and 80 % of the current contributions for the desired CCC from the LAB and supercapacitor, respectively, to ensure enhanced battery life. The results indicate that the proposed controller improves the battery life from 5 to 7.9 years. The HBSCESS allows only 0.09 battery cycle loss during cranking. The optimal sizing of the HBSCESS components, specifically the battery-to-supercapacitor ratio, is crucial for achieving an efficient and lightweight system. The analysis focused on understanding the effect of this ratio on the weight of the HBSCESS. The results obtained for 50, 70, and 80 Ah battery capacities revealed optimised weights of 312, 404, and 458 Wh/kg, respectively. HBSCESS demonstrates higher energy density and power capabilities by efficiently synergising the battery and supercapacitor. • Optimised double integral sliding mode-genetic algorithm controller boosts battery life & system efficiency in vehicle cranking. • Smart battery-supercapacitor synergy boosts cranking, enhances performance & cuts cycle loss by efficiently distributing current. • An optimal design for an efficient and lightweight hybrid battery-supercapacitor energy storage system.