Enhancing Battery Performance with Active Balancing and Fault Tolerance in Lead-Acid Energy Storage Systems

This paper proposes a battery management system (BMS) with integrated balancing and fault-tolerant capabilities, designed for series-connected battery energy storage architectures. The system incorporates cascaded half-bridge multilevel converters and a digital signal processor (DSP), employing a sorting-based level-shifted pulse width modulation (PWM) technique to dynamically regulate the charging and discharging current of each battery module. This enables rapid balancing control during charging, discharging, and idle conditions. Compared to conventional methods, the proposed approach effectively suppresses inter-cell voltage deviation to within 0.1 V, prolongs battery lifespan, and eliminates the need for additional balancing circuits. The system also features fault detection and bypass functionality. When a faulty battery module is detected, the system automatically isolates the affected unit and adjusts the converter control levels to maintain stable output. Experimental results confirm that the proposed BMS achieves high-efficiency balancing and stable power delivery even in the presence of aged or degraded batteries, demonstrating its practical applicability and potential in modern energy storage systems.