Hybrid Battery–Supercapacitor Energy Storage for High-Power EV Charging Stations

Abstract

High-power electric vehicle (EV) charging stations can impose large and rapidly varying electrical loads on the grid and on local storage systems. A battery-only storage arrangement can provide substantial energy capacity, but repeated high-current transients may increase electrical and thermal stress and can accelerate ageing. This project presents a hybrid energy storage approach that combines a battery bank with a supercapacitor bank so that energy and power requirements are handled by complementary storage devices. The proposed station uses bidirectional DCDC converters, a common DC bus, and an energy management system (EMS) to coordinate grid supply, renewable generation, battery storage, supercapacitor support, and fast charging demand. During normal charging intervals, the battery supplies the slower and sustained component of power, while the supercapacitor responds rapidly to shortduration peaks and fluctuations. The framework includes demand acquisition, signal decomposition, state-of-charge monitoring, converter control, power allocation, and performance evaluation. Key evaluation indicators include peak current, DC-bus voltage variation, battery stress, charging response, and renewable-energy utilization. The resulting architecture provides a practical foundation for high-power charging stations that require smoother power flow, flexible storage operation, and improved utilization of battery capacity.