The problem of state identification has always been an important factor limiting the large-scale development of battery energy storage systems. At present, impedance-based state identification methods have been widely studied. The premise of this method is to accurately measure the impedance of the battery. This article proposes an online battery impedance identification method based on a novel reconfigurable circuit. This article first introduces the shape of the reconfigurable circuit and theoretically analyzes the feasibility and rationality of the method. Then, a simulation model was constructed to verify the feasibility and effectiveness of the method. Finally, the battery impedance results were obtained and the method was validated.