“…In the first place, Tian et al and Tian et al use the second-order RC equivalent circuit model to estimate state of charge (SOC) and SOH, respectively [6,7]. To get a better result, Li et al introduction of battery hysteresis voltage segmentation into a second-order RC model to form an improved second-order RC model, and the estimation results error is under 0.0431 [8]. Furthermore, for researching charging safety and SOC, Zhang et al and Xu et al use an improved back propagation (BP) neural network to get results [9,10].…”