Lithium battery residual life prediction method based on cubic polynomial function

The invention discloses a lithium battery residual life prediction method based on a cubic polynomial function. The method comprises the following steps: A, establishing a lithium ion battery degradation model based on a nonlinear Wiener process of the cubic polynomial function; b, a subjective parameter estimation method based on envelope extraction: (1) a lithium ion battery real degradation track estimation method based on envelope extraction; (2) two-step off-line parameter estimation; c, online parameter updating based on Kalman is carried out; and D, probability density distribution of the remaining life of the lithium ion battery. According to the method, the problems that a nonlinear Wiener process degradation model is simple and the parameter estimation precision is not high can be solved, the individual life and the overall reliability life characteristic quantity of the lithium ion battery are predicted and analyzed, and the method can also be used as an effective analysis tool for predicting the r