Research Progress Of Accelerated Life Test And Life Prediction Of Lithium Ion Battery

Lithium-ion battery is getting more application than ever which brings an increasing demand of high performance and long life.In order to fully improve the performance of lithium-ion battery,the research on the life of lithium ion battery has stepped onto the historical stage.From the decay mechanism analysis and accelerated life test to the residual life prediction,the life evaluation methods of lithium-ion battery is emerging in an endless stream.Therefore,it is necessary to summarize and analyze the research progress of lithium-ion battery life evaluation.In this paper,the research status of accelerated life test of lithium ion battery is analyzed from two aspects including influencing factors and performance attenuation mechanism.The influences of ambient temperature,charged state and cyclic rate on lithium-ion batteries were compared and analyzed.The attenuation mechanism of lithium-ion batteries under different types of accelerating stresses and different values of accelerating stresses were analyzed from the perspectives of negative electrode,positive electrode and the amount of active lithium storage.It is found that different accelerating stress conditions,different accelerating stress ranges and different battery systems will have different effects on the attenuation mechanism of lithium ion battery.However,in recent years,accelerated life attenuation test seems to have hit a bottleneck since no new accelerated stress has been investigated,which results in no big breakthrough in accelerated life test.In this paper,based on the working conditions of vehicle-borne lithium ion battery,pulse rate is proposed to accelerate the attenuation of lithium ion battery.However,more in-depth analysis and characterization are needed to clarify the impact of pulse rate on the life of lithium ion battery.This paper summarizes four life prediction technologies including the empirical method,the method based on model,data driven and integrated regarding to research progress on lithium ion battery life evaluation.We make a comparison of different life prediction methods considering model complexity,difficulty of receipt collection,prediction precision and the degree of use generalization,the direction and hotspot of future research have also been pointed out.The method based on experience has the diagnostic accuracy and reliability that other methods cannot match.However,it is time-consuming,requires a large amount of experimental data as the basis,and has poor universality,so it is difficult to be applied in practical engineering.The model method is easy to implement embedded management,but the electrochemical mechanism model calculation is too much.The structure of the equivalent circuit model is simple and the calculation is small,but the estimation accuracy is affected by the model structure.The data-driven method can make full use of the operating data of the battery,and combine the battery performance parameter database of large samples with the intelligent learning algorithm,so the training cost is high and the model complexity is high.The synthesis method can give full play to the advantages of each model and algorithm,which is an important research content of developing battery health state diagnosis technology.The future life prediction is still mainly based on the synthesis method,and the future research direction is mainly to simplify the model and improve the prediction accuracy.