Research Of Lithium-ion Battery Life Prediction Technique Based On Capacity Compensation And Attenuation Model

Compared with other commonly used batteries,lithium-ion batteries are featured by high energy density,long cycle life,no memory effect and slow self-discharge,and thus have applied widely in the area ranging from portable electronics,electric vehicles to military weapons.Accurate prediction of lithium-ion battery remaining life is an important foundation of developing replacement strategies and ensuring its security service.It has been found that lithium-ion battery life model stands out with non-linear,multi-factor correlation characteristics.At present,many models are built based on data-driven methods,however,their performance and effic iency largely depend on the parameters and structure.If electrochemical mechanism analysis is introduced into life prediction field,the limitations of the data-driven model could be avoided.Therefore,this article attempts to analyze the degradation of battery,builds capacity fading model,reveals the influence of environmental temperature and relaxation period,and then makes life prediction implementation progrem.The main contents are as follows:(1)The structure of lithium-ion batteries and basic working principles are discussed,the battery capacity fading mechanism is analyzed,the influence of temperature and other factors related to capacity is studied,and then a lithium-ion state model is obtained.(2)By studying the mechanism of ion diffusion law,environmental temperature correlation model and relaxation period correlation model are established.The parameters can be estimated by the least squares algorithm and nonlinear least squares algorithm respectively.(3)According to Markov theory,the capacity fading model can be built.Then particle filter(PF)is introduced,and the prediction process is explained.And particle diversity degradation problem is solved by increas ing random noise.(4)Lithium-ion battery life prediction implementation progrem is proposed,the battery charge and discharge test system is designed and built,the model results is validated,the implementation progrem is comparatively analyzed.The results demonstrates that compensation method based on correlation factor helps to improve life prediction.