Research On Fast Charging Of Lithium-ion Battery Based On Battery Model

Faced with the increasingly serious problem of air pollution and oil shortage,electric vehicle has become a major research target of many car companies and research institutions relying on the advantages of power driven,high energy efficiency and zero emissions.At present,the electric vehicle technology is developing rapidly,but its battery charging needs a long time,which is a bottleneck and restricts the popularization and promotion of electric vehicles.Therefore,it has great significance to study the fast charge technology of the battery to speed up the popularization of electric vehicle.This paper selected the lithium-ion battery with excellent performance as a research object,introduced the principles of the electrochemical reaction of lithium-ion batteries,and analyzed the battery polarization phenomenon.Based on the PNGV model,the experiments of testing battery performance parameters under different conditions were designed,and the battery model parameters were also identified.On the basis of analyzing battery model parameters and summarizing its variation laws,the lithium-ion battery charging principle was determined and a battery fast charging method was developed.Then,the values of charging parameters were determined by related experiments and tested battery model parameters.Due to the battery had the characteristics of nonlinear and time-varying parameters,the fuzzy PID controller of battery charging was selected and designed.And in order to verify the effect of the controller,a simulation model in Simulink environment was set up.At the same time,the charging experiment platform was constructed,and contrast experiments were finished with different charging methods,which verified the combination method could improve charging rate and shorten charging time of the battery.In this paper,the main circuit and control circuit of lithium-ion battery charging system were designed,and the components parameters of main circuit were calculated and selected.To drive the main circuit work,a control circuit was designed including the PIC18F4580 microcontroller work system,IGBT driving circuit and current voltage temperature acquisition circuit.Finally,the control software of main program was designed according to the charging method,and the process of each subroutine was designed and described.