Parasitic Parameter Extraction And Electromagnetic Interference Research Of Lithium-ion Power Battery Pack

Power Lithium battery is one of the important components of electric vehicle and hybrid electric vehicle.However,the research on the electromagnetic interference of the Lithium battery of the electric vehicle is very rare.Electromagnetic interference caused by the transient of the power Lithium-ion battery voltage or current,parasitic parameters of Lithium battery itself and the parasitic parameters between the Lithium battery and the chassis has not been considered.Study on parasitic parameters of power lithium battery,interference mechanism of vehicle electronic components and suppression measures will help to improve the operational reliability of new energy vehicles.The main research contents and results of this dissertation are listed as follows.(1)In this paper,based on the analysis of the physical structure of the battery,an experimental platform for parasitic extraction of Li-ion battery based on the precision impedance analyzer is built,and the parameters of parasitic inductance and parasitic capacitance of the passive device and the lithium battery are extracted.(2)Research platform for interference of batteries is built to study and restrain the electromagnetic interference caused by the Lithium battery in the case of transient current.(3)An experimental method based on the sensitivity of the sensitive components in the battery circuit is proposed.The feasibility and validity of the method are verified by experimental measurement and analysis and this method has certain universality to other sensitive parts of the battery pack circuit.At the same time,it shows that the electromagnetic disturbance reaches certain limit,which will cause the fluctuation of the output of sensitive parts in the battery circuit,and some optimization filtering measures need to be taken.(4)Based on the electromagnetic interference in the case of transient current and the impedance spectrum curve of the components such as capacitance and inductance,the structure of the filter and the selection of components are determined and the electromagnetic interference filtering circuit of lithium battery group is constructed.The results show that the EMI average attenuation in 25dB-35 dB.So the filter circuit composed of X capacitor,Y capacitor,common mode inductor and differential mode inductor can effectively suppress the conducted electromagnetic interference in the battery loop system and improve the safety and reliability of sensitive components in the battery circuit.