The Research Of Charging Equalization Control For Li-ion Power Battery Of Electric Vehicle

The power battery is the key part of the electric vehicle,the performance of the power battery decides the performance of the electric vehicle.According to the development on battery,Li-ion battery has some good characteristic,such as high operating voltage 、high energy ratio、long life、low self discharging ratio、no memory effect 、no pollution and so on,which has obvious superiority beyond others.So it is very suit for the electric vehicle as its power battery.When the Li-ion battery series provide the energy to the electric vehicle,these Li-ion battery begin to produce the problem of the energy disequilibrium.The problem decreases the ability of providing electricity and cuts down the battery life,which directly influences the performance of batter.In order to solve the problem,adding battery manage system to the electric vehicle is the best effective way.So paper does the research on the Li-ion battery charging on the electric vehicle,the main research content as follows:①Summarying the equilibrium technology development situation of the electric vehicle at home and abroad at the moment 、studying the characteric of the Li-ion battery 、analying the reasons that the energy disequilibrium about the Li-ion battery of the electric vehicle,from above study can paper provide some measures to solve the disequilibrium problem.②Summarying the common equalization circuit,Analying the merits and demerits about kinds of equalization circuit,from above discussion can paper choose the symmetrical inductance equalization circuit.Aiming at the equalization task of the paper,paper finishes the components and parts choosing about equalization circuit:Power inductor 、MOSFET、Schottky diodes.Paper makes two stages equalization strategy:Quick equalization stage 、 Equalization amendment stage.At quick equalization stage,batter entries charging process.Equalization strategy designs that control the difference value under 50 m V at the voltage across the plateau and control the difference value under 30 m V at terminal voltage plateau. At equalization amendment stage,battery keeps quietness. Equalization strategy continue equalization battery to make sure difference value under 30 m V. Building the modern of the system on simulink.Meanwhile,paper demonstrates that two stages equalization strategy is validity and feasibility by simulation experiment.③Putting forward the whole design program about the electric vehicle charging equalization control system,the program includes detection、operation、control and show. Combining with the theory research,paper finishes designing the hardware and making the model machine.④Making charged equalization control experiment on the model machine.Finally paper acquires the good equalization effect,and successfully control the difference value under 30 m V.According to the above work,paper successfully demonstrates the validity and feasibility of the design in practical application and shows the value and meaning of the design.