Research On Safety Monitoring System Of Electric Vehicle Ternary Lithium Battery

With the rapid development of new energy vehicles,ternary lithium batteries have become the main power source of electric passenger vehicles due to their high energy density and superior comprehensive performance.However,due to the particularity of the materials in ternary lithium batteries,compared with other lithium batteries,it is easier to cause thermal runaway.At present,the state safety monitoring and control system of ternary lithium battery mounted on electric vehicles is not effective,which has become one of the important factors restricting its further development and application in all kinds of automobiles.Therefore,in order to improve the safety of electric vehicles equipped with ternary lithium batteries,it is of great significance to study the thermal runaway safety monitoring system.This paper briefly analyzes the internal structure composition,charging and discharging principle,heat generation mechanism and heat transfer characteristics of ternary lithium battery and mainly analyzes and studies the thermal runaway theory of ternary lithium battery,and summarizes the concept,inducement,trigger mechanism,side reaction and thermal runaway characteristics of ternary lithium battery.At the same time,this paper analyzes the technical standards and specifications for the prevention and control of ternary lithium battery.This paper takes the power battery box of a pure electric vehicle powered by ternary lithium battery of Beijing automotive company as the research object.The thermal runaway characteristics of ternary lithium battery are taken as the control parameters,mainly including temperature,flame,gas,smoke and air pressure inside the battery box,formulating the control scheme and control strategy of sanyuan lithium battery thermal runaway safety monitoring system.Furthermore,according to the characteristic parameters of ternary lithium battery to carry out the hardware selection of safety monitoring system.According to the thermal runaway ignition characteristics of ternary lithium battery,analyzing and studying the active fire extinguishing of device,selecting the Water Mist Extinguishing Egent as extinguishing medium.In order not to change the structure of the battery box,designing the layout of the nozzle of the fire extinguishing of device in the battery box.Using Pyrosim simulation software establishes the fire extinguishing system model with water mist,simulating the dynamic extinguishing process of water mist extinguishing system,when the fire source is near the middle,upper left corner and lower right corner of the battery box.The simulation results show that no matter where the ignition source is,the maximum temperature of the battery box varies in the same tendency(the temperature drops sharply).It shows that the fire extinguishing effect of the layout plan is effective.In this paper,building a simulation test bench for thermal runaway safety monitoring system of ternary lithium battery.In Keil u Vision5 IDE program development platform for the thermal control safety monitoring system software design.Designing the hardware circuit design of each module of the simulation test device.According to the control strategy of characteristic parameters of ternary lithium battery,designing the temperature,gas,flame,air pressure inside the battery box and smoke simulation monitoring tests.The test results show that the monitoring effect of each control parameter is good,the actuator responds timely,and all conform to the control strategy logic of the designed thermal runaway safety monitoring system.The monitoring system simulation device is feasible and can complete the safety prevention and control function of the safety monitoring system simulation device.