"Energy Optimization in Electric Vehicles: Model-Based approach for Lithium-Ion and Sodium-Ion Hybrid Energy Storage System "

In recent years, the transition to fully electric vehicles has emerged as one of the most effective strategies to combat climate change and reduce environmental pollution. Among the various energy storage technologies, lithium-ion batteries are the most widely used in electric vehicles due to their high energy density and reliability. This thesis aims to explore how the performance of electric vehicles powered by lithium-ion batteries can be enhanced through the integration of sodium-ion batteries. Specifically, the study will investigate the potential benefits of combining lithium-ion and sodium-ion batteries, with a primary focus on reducing the C-rate experienced by the lithium battery. Lowering the C-rate is crucial for preserving battery health and preventing degradation over time, which in turn can improve overall vehicle performance and longevity. To achieve the objectives of this research, a model-based analysis will be conducted across various scenarios. Initially, the analysis will focus on a real vehicle equipped with a lithium-ion battery pack. Following this, the same procedure will be applied to the vehicle, but with an energy storage system that incorporates both lithium-ion and sodium-ion batteries. Key performance metrics, such as C-rate and driving range in kilometres, will be evaluated to highlight the differences between the two configurations. In the dual-battery scenario, the lithium-ion and sodium-ion batteries will be connected in parallel using a DC-DC converter. This setup will allow both batteries to share the load demand, except in specific cases where one battery may need to handle the load independently. A carefully designed control strategy will be implemented to manage the current flow between the two batteries. The primary objective of this control strategy is to reduce the stress on the lithium-ion battery by distributing the load demand and leveraging the contribution of the sodium-ion battery. Furthermore, a scaled-down model of the vehicle will be analysed under both configurations: with only a lithium-ion battery pack and with a combination of lithium-ion and sodium-ion batteries. This secondary study aims to generate theoretical results that can be compared with experimental data obtained from testing a prototype of the vehicle's powertrain components. Through this comprehensive analysis, the thesis seeks to demonstrate the potential advantages of integrating sodium-ion batteries into electric vehicles, ultimately contributing to advancements in energy storage systems and sustainable transportation.