Research On Cycle-life Predictions And Automatic Evaluation System Of Power Battery

Because of diversified energy sources,small environmental pollution and high energy utilization rate,electric vehicles have become the key way to solve the problem of energy and environment in the present world.For electric vehicles,power battery's performance and price are the main bottlenecks that restrict the course of the large-scale industrialization and functionalization.In recent years,safety accidents triggered by power battery happen frequently,experiment and test standard of battery groups is not perfect.In order to ensure power battery run securely,efficiently and reliably,we must understand internal and external characteristic change of power battery deeply and realize the rapid and accurate estimation for battery status.Taking lithium-ion power battery as the research object,this paper aims to develop an automatic evaluation and simulation system software of power battery with independent intellectual property rights which can provide support for battery power's production,application and scientific research etc.The detailed research contents are as follows:First of all,taking LiFePO4 battery as the research object,a battery test platform has been set up and a set of battery test plan has been designed which including the maximum available capacity test,HPPC charge-discharge test,different ratio test and life cycle test.Then according to the experimental data,the basic characteristics of LiFePO4 battery have been analyzed:discharge ratio,discharge capacity,internal resistance and aging properties and so on that laid the data and theory foundation for prediction of lithium-ion battery cycle life.Secondly,selecting the particle filter algorithm to predict the lithium-ion battery cycle life,the main principle of particle filter algorithm is analyzed,battery capacity degradation model is established,the working process of the particle filter algorithm is expounded and the battery life predictions are realized finally.Aiming at the defect of standard particle filter algorithm,the improved extended Kalman particle filter algorithm is used to predict the battery cycle life.As a result,this algorithm is proved to be has a higher estimation precision which is a reliable life prediction algorithm for power battery automatic evaluation and simulation system.Finally,detailed schemes of power battery automatic evaluation and simulation system are made including power battery test software,power battery automatic evaluation software,power battery simulation software and database.At present,the core function modules of power battery automatic evaluation software and power battery simulation software have been completed based on the LabVIEW software development platform,combining with the MySQL database and data analysis software MATLAB.The finished product of power battery automatic evaluation and simulation system does not rely on any other software platform to run that has great realistic significance and academic value.