Switched supercapacitor based active cell balancing in lithium-ion battery pack for low power EV applications

Abstract

The two-wheel segment in the EV sector is significant for the economic development of society due to its affordability and convenience. Low budget designs need energy storage system (ESS). This research paper aims to present a battery pack suitable for the application, with a sizing and rating of 48 V, 3.84 kWh, and 80 Ah capacity. To achieve this, 260 cells of the 21700 model of lithium-ion cells are used in series-parallel combinations, following the current standard specifications. The performance of the designed battery pack is evaluated for the urban dynamometer drive schedule (UDDS) drive cycle current profile as the load. During operation, the differences in the manufacturing process and varying internal resistances of the individual cells cause an imbalance in the cell voltage levels and state of charge (SoC). To overcome this issue an active cell balancing method using the switched supercapacitor (SC) with a simple on-off hysteresis control logic is proposed. The effectiveness of this approach is validated through MATLAB/Simulink simulations. The simulation results demonstrate the proposed cell balancing approach’s excellent operation speed and efficiency. Additionally, the construction of the circuit is simple and economical. On comparison with the state-of-art it may be concluded that the proposed system can improve the performance and cycle life of the battery pack with minimum control complexity.

Keywords

• Active cell balancing
• battery pack design
• lithium-ion 21700 cell model
• on–off hysteresis control
• switched supercapacitor
• Electrical and Electronic Engineering