Flyback converter employed non-dissipative cell equalization in electric vehicle lithium-ion batteries

Abstract

The effective and dependable usage of rechargeable batteries has emerged as a central topic for automobile manufacturers in the wake of the rise of electric vehicle technology. When it comes to rechargeable batteries with high specific energy and specific power, lithium-ion battery technology is the most well-known. The low terminal voltage battery cells in the lithium-ion battery pack are linked in series to provide the necessary voltage for the electric vehicle system. The low charge cell in the string limits the usable capacity of the battery pack, though. Disturbances in the battery pack's charge are due to variations in manufacturing quality and to the unique operating circumstances of each individual cell. These inconsistencies cause a decline in usable capacity, a quickening of cell deterioration, and, most significantly, substantial safety issues including overcharging. The cell balancing controller is a critical component of the battery management system in all electric vehicle and hence performs a crucial function in extending battery life and ensuring the battery's safety. This paper presents a hardware-in-the-loop simulation of a RCD buffer included fly-back converter-based active cell equaliser for lithium-ion batteries in electric vehicles. With the equaliser, all the series-connected cells may be brought to a more even State of Charge. All of the MOSFETs employed in the proposed approach are selected for their low conduction loss. The suggested equaliser is able to produce equalization without the need for a switch driving circuit or sophisticated control method, allowing it to function automatically. The system's overall price is reduced, and the balanced circuit's complexity is considerably reduced. In-depth discussions on circuit configuration, operating principle, modeling, and design consideration are presented. Finally, both Matlab simulation results and Hardware-in-loop based experimental findings are offered to back up the claims that the suggested cell equaliser is both practical and effective.