PERFORMANCE ENHANCEMENT OF ELECTRIC VEHICLE HYBRID ENERGY STORAGE SYSTEMS USING ULTRACAPACITORS AND BATTERY AGING ANALYSIS

Abstract

With the proliferation of Electric Vehicles (EVs) and the need for efficient, reliable, and sustainable energy storage solutions that enhance vehicle performance and battery life, the market is experiencing a surge in demand for such solutions. Lithium-ion batteries are popular in EVs due to their high-energy density and durability, but they are sensitive to degradation from repeated charging and discharging cycles, heat effects, heavy current surges and aging. This can lead to reduced battery capacity, high battery internal resistance, and a negative impact on the vehicle's performance. This project aims to address these constraints by developing an Ultracapacitor-Assisted Battery-Based Hybrid Energy Storage System (HESS) for Electric Vehicles (EVs) in the presence of battery ageing. The proposed system incorporates a Model Predictive Control (MPC) based Energy Management Strategy to optimize the power distribution, bidirectional DC-DC conversion, lithium ion battery and an Ultracapacitor. The battery provides the average energy demand and the ultracapacitor provides high power demand when accelerating and for regenerative braking. This synchronized operation helps to reduce the fluctuation of battery current, reduces thermal stress, and improves battery energy utilization. The proposed methodology is different from the traditional ones that assume a constant C-rate during the battery charging process because it takes into account a real-time battery aging model that takes into account the variable C-rate conditions which makes the estimation of battery degradation more accurate. The system is designed and tested in MATLAB/Simulink under similar driving conditions. The simulation results show better power sharing, voltage stability, regenerative energy recovery, less battery degradation and extended battery life. This proposed HESS is a smart, cost-effective and energy efficient solution for next generation EVs and supports sustainable transportation and advanced energy management applications.