Research On The Rapid Charging System Of Li-ion Power Battery

Since the beginning of the 21 st century,scientists have begun to explore the green energy instead of fossil fuels in order to reduce the environmental pollution caused by traditional fossil fuels.At present,China has also begun to develop new energy vehicles to reduce environmental pollution and energy demand.Lithium iron phosphate battery has the advantages of low cost,high stability and long service life,so it is widely used in electric vehicles.At present,the fast charging method of lithium ion power battery is large current charging.This method has a great damage to the battery,which seriously affects the life of the battery.But the conventional charging method is too long to charge,which leads to the short mileage of electric vehicles.Therefore,it is of great significance to design a fast,efficient and lossless lithium ion power battery rapid charging system.This topic to lithium iron phosphate battery as the research object,through the research on lithium ion power battery charging and discharging characteristics,combined with the 3.2 V / 20 ah lithium iron phosphate monomer battery charging and discharging experiments,the author understands its under different charging and discharging rate of features,and the polarization of the battery to the battery charge and discharge.On this basis,combining with the three laws of mas for lithium ion power battery quick charging method,the author determines the charging amplitude with negative pulse fast charging method,charge and discharge time,discharge amplitude time,and puts forward a kind of lithium ion power battery with negative pulse fast charge method.In order to verify the effectiveness of this method,a quick charging strategy model of lithium ion power battery was built in Simulink,which included lithium ion power battery model,charging device model and control strategy.By comparing the actual charging data and the simulated charging data,the validity of the model is verified.On this basis,the proposed fast charging method is put into the model to simulate.Compared with the proposed control method and simulation data,the correctness of the charging strategy model is verified.On this basis,this paper designed a lithium ion power battery quick charging system.In order to validate its feasibility,the hardware model and software model are built in Simulink.The hardware model includes single-phase bridge rectifier circuit model,full-bridge dc-dc circuit model,transformer model,battery model and power switch tube model.The software model includes SPWM model,PID control model and control strategy model.The feasibility of the system is verified by simulation.Under the condition that the charging capacity reaches 80% of the total electric quantity,the fast charging method with negative pulse is compared with the traditional fast charging method by this model.Results show that with the negative pulse fast charge method used in the 1819 s,the traditional large current fast charge method used in 2880 s.The fast charging method with negative pulse saves 1061s(36.84%)compared with the traditional fast charging method,and verifies the effectiveness of the proposed fast charging method with negative pulse.On this basis,a prototype of lithium ion power battery rapid charging system was developed.Under the premise that the charge capacity reached 80%,the fast charging method with negative pulse saves 652 s(22.64%)compared with the traditional fast charging method.To a certain extent,the system can realize fast,efficient and lossless charging.