Design of semi-actively controlled battery-supercapacitor hybrid energy storage system

Abstract

For vehicle propulsion, electric vehicles (EVs) utilize lithium ion (Li-ion) based battery storage system. Electric powertrain provides high Efficiency, but Li-ion cells liable to degradation with increase in temperature and load. While a larger energy storage system (ESS) produces more power, but it also increases the ESS's cost, volume, and size. A hybrid energy storage system (HESS) based on batteries and supercapacitor can be utilized to minimize total ESS size and improve performance during heavy loading conditions, with the supercapacitor provide power during charging/discharging peak power. Battery and supercapacitor are connected together with the help of a DC-DC Converter. HESS is a single-unit battery and supercapacitor that combines the benefits of high battery energy density and high supercapacitor power density. Whereas Sizing of HESS is a challenging task because of adding supercapacitor it increases overall size and cost of ESS, to address this issue in this study particle swarm optimization (PSO) is used to optimize HESS size and increase battery cycle life (BCL). The MATLAB/SIMULINK environment is used to model both the Battery Energy Storage System (BESS) and the Hybrid Energy Storage System (HESS). Optimized results are used to compare battery cycle life of BESS and HESS. The optimization findings under the Urban Dynamometer Driving Schedule (UDDS) are compared to the battery-only ESS results, which show a 8.927 percent increase in battery cycle life.