State-of-Charge Estimation of Reconfigurable Lithium-ion Batteries: A Nonlinear Switched Approach

The estimation of the state-of-charge (SOC) in lithium-ion batteries has garnered significant attention, with current research primarily concentrating on individual batteries. In practice, however, lithium-ion batteries often require connection to a balancing circuit to correct battery imbalance. In such cases, the system topology differs from that of an individual battery. Therefore, it is essential to account for this change. This article proposes a method for estimating the SOC of lithium-ion battery cells within reconfigurable circuits. We established a switching system model for lithium-ion batteries in reconfigurable circuits. We then design a nonlinear switching observer and examine its stability. Additionally, we conducted extensive experiments to evaluate the proposed observer’s performance and compared it with other observers.