Battery Module Design And Thermal Characteristics Analysis For The Pure Electric Vehicle

Environmental pollution and energy shortage are two major challenges of today’s automotive industry faces.Automobile manufacturers of various countries are successively proceed vigorously develop new energy vehicles, our country has even taken the development of the new energy vehicles as a national strategy. Pure electric vehicles rely solely on electricity as an energy-driven vehicles with low noise, zero emissions, and simple structure, which is currently one of the most promising new energy vehicles. Technology of battery has been one of several key technologies of electric vehicles.The characteristics of safety, high energy density, stable performance and good temperature uniformity is an essential trait for excellent battery pack.This paper takes the postdoctoral project of Changfeng Group as the basis,and takes a company’s polymer ternary lithium-ion battery with soft pack as an object,conducts the research and design of the cells and batteries modules from the view of thermal by experiment and simulation.The main work is as follows :(1) The structure and principles of single battery was analyzed.By the method of trial,the effect of temperature on the internal resistance, voltage,cycle life, charge and discharge characteristics,charge maintenance,security was researched.In order to study the cell’s heat generation during battery discharge, the cells were carried out under adiabatic temperature rise testing and natural cooling conditions of different discharge currents.(2) Based on the characteristics of the cells, two battery module with different thermal design was designed and was successfully trial-produced.The advantages and disadvantages of the two modules analyzed bind battery module design principles.(3) The heat and heat transfer mechanism of lithium-ion battery was analyzed.The rate of heat generation of the battery was calculated by using the model established by Bernardi et al.Application of ANSYS/workbench software,the temperature of the battery case was analyzed and calculated at different discharge rate,and so was to under different ambient temperature conditions of the cells.(4)The thermal simulation model of two different thermal design of the battery module was established.The different modules at different discharge rate of temperature distribution and temperature rise was analyzed by the application of ANSYS/workbench software.In order to verify the accuracy of the module thermalsimulation,the temperature testing of the 8 parallels and 12 series battery module under different discharge rate was conducted.The simulation analysis of the discharge temperature of a plurality of modules to expand the program was conducted.Then the battery pack constituted by 8 parallels and 12 series batteries was introduced.