Research On The Quick Charging Technology Based On The Li-ion Power Battery Used By EV

In recent years,with the rise and rapid development of electric vehicles,electric vehicle charging attracts more and more attention of people.Compared with the traditional fuel vehicles,electric vehicles have the advantages of energy-saving,environmental protection,but it's slow charging problem is always being criticized,and this problem become the main bottleneck of the electric car development.At present most of the electric car battery is lithium ion power battery.Although some of the new battery technologies emerge in endlessly,they are mostly at the test stage,no large-scale production and application.In this context,doing deep research on charging technology based on lithium ion power battery,in order to improve the charging speed,at the same time reduce the impact on battery life as far as possible,is very important.In this paper,the lithium ion power battery is thoroughly researched.The software MATLAB is used as a tool to simulate the charge and discharge process of the lithium ion power battery.The battery voltage,SOC and other factors,which are changed in the process of charge and discharge,are analyzed in this paper.The charge and discharge experiment platform is set up to do some charge and discharge experiments using different methods.Through the comparison and analysis of the experimental results,the feasible of the charging method proposed in this paper is verified.The following work is mainly completed in this thesis:1.The structure and working principle of lithium ion power battery are studied in this paper,then the charging and discharging properties of lithium ion power battery are researched through the charging and discharging experiments.The polarization phenomenon in the process of battery charging and discharging is analyzed.2.Five kinds of lithium ion battery model are studied,then PNGV equivalent circuit model is chosen to be analyzed.Battery model parameters identification on the basis of PNGV equivalent circuit model is carried out.3.Battery SOC estimation methods are introduced,and the four estimation methods are analyzed and compared.4.Step reflex charging method is put forward based on the study of the existingcharging methods.The feasibility of the proposed charging method is proved by using MATLAB simulation.The charging and discharging plan is designed according to the step reflex charging method.Then the charging and discharging experiment platform is set up and used to do experiments.Through the comparison and analysis of the experimental results,the feasible of the charging method proposed in this paper is further verified.