Active Cell Balancing Design Integrated With SoC Estimator In Lithium-Ion Batteries

Abstract

The reliability and safety of lithium-ion batteries in electric vehicle applications significantly depend on accurate State
of Charge (SOC) estimation and effective cell balancing mechanisms. This study proposes the design of an active cell
balancing system integrated with an SOC estimator to improve the performance, lifespan, and thermal stability of
lithium-ion battery packs. The research adopts a Research and Development (R&D) approach, involving both hardware
and software design. The hardware utilizes an Arduino-based control system to monitor individual cell voltages,
temperature, and current, while the software implements an algorithm for active energy redistribution among cells to
achieve real-time balance. A 4S1P lithium-ion battery pack (3.7V/2500mAh per cell) was developed and experimentally
tested. The results demonstrate that the integrated active balancing system effectively minimizes voltage deviation
between cells and maintains uniform SOC levels, reducing overcharge and overdischarge conditions. Consequently, the
proposed system enhances energy utilization efficiency and extends the operational life of the battery. The integration
of SOC estimation into the active balancing control loop offers a promising approach for intelligent Battery Management
System (BMS) design in electric mobility and renewable energy storage applications.