Electric vehicle lithium battery SOC estimation method based on UKF

The invention discloses an electric vehicle lithium battery SOC estimation method based on UKF, and relates to the field of lithium battery SOC estimation methods. The method comprises the five stepsof: (A), building a Thevenin-based improved circuit model of a lithium battery according to the dynamic characteristics of the lithium battery; (B) establishing a function relationship between Thevenin-based improved circuit model parameters and SOC, and establishing a battery system state space model; (C) discretizing the battery system state space model; (D) establishing a lithium battery SOC estimation model based on a UKF algorithm to estimate the SOC of the lithium battery; and (E) building a hardware platform of a battery detection system, and verifying the applicability of the UKF algorithm. According to the method, the problems of parameter change, inaccurate noise statistical characteristics and self-correction characteristics in the system state calculation process can be effectively solved, the linear e