Development of battery-supercapacitor management systems for electric vehicles

Electric vehicles (EV) consuming low-carbon electricity are important assets to decarbonise the transport sector. Currently, most battery electric vehicles including Tesla and Nissan use lithium-ion (Li-ion) batteries as the energy source. Li-ion batteries have high energy and power capacities and have found commercial success in the EV markets. However, Li-ion batteries suffer from significant cell degradation during deep and rapid discharge. The driving behaviour of individuals directly influences the energy discharged from the EV. To prolong Li-ion batteries lifetime and for optimal operation, supercapacitors can also be an additional energy source with rapid discharge characteristic and high power density. For EVs, the battery management system ensures that the rechargeable battery operates within the safe operating region and also with maximum efficiency.

This research project aims to study the technical and economic viability of a hybrid energy storage system for EVs comprising of Li-ion batteries and supercapacitors. The system and its components will be modelled to evaluate the energy storage system's electrical and thermal performances under different driving cycles. The objectives of this research project include:

To develop a battery-supercapacitor management system for the optimal operation of Li-ion battery and supercapacitor in EVs.
To determine the optimal sizing of energy and power capacities for the battery-supercapacitor system.
To investigate the electrical drive system (e.g., power converters) with battery-supercapacitor management systems.
To validate the system with hardware-in-the-loop and software-in-the-loop studies.
To investigate the techno-economic viability of the hybrid energy storage system in EVs.