Design And Thermal Simulation Of Soft-package Lithium-ion Battery Module With Laminated Structure

Poor environmental problems have forced many governments to take action in the field of new energy,and electrification has become an important trend in the development of automobiles.As the core component of pure electric vehicles,battery life is a key factor affecting the development of electric vehicles,especially the battery overheating affects its service life.Therefore,it is necessary to analyze the heat generation mechanism of the battery and take heat dissipation measures.In this paper,the 37 Ah laminated soft-package ternary lithium-ion battery is studied.The main work is as follows:(1)In-depth understanding of the working principle and basic performance parameters of lithium-ion batteries,the effects of temperature,rate and cycle number on the basic performance parameters of the battery were developed.The effects of temperature and SOC on the internal resistance and open circuit voltage of the battery were studied.The temperature rise test of the battery under different charge and discharge rates obtained the corresponding data.(2)According to the principle of battery module design,the advantages and disadvantages of the two schemes are compared,the superiority of the analysis and the series connection is determined,and the welding mode of the battery in series and parallel when the module is tested is determined.(3)In-depth understanding of the heat generation mechanism of lithium-ion batteries,learning the basic theory of heat transfer,constructing a three-dimensional physical model of single cells,fitting the heat generation power formula of batteries,positive and negative ear at each magnification,and writing the heat simulation internal heat source code.The literature theory is used to calculate the thermal properties of the battery,and the thermal simulation of the single cell in different environments and different discharge rates is performed.The simulation results are verified by comparison with experimental data.(4)The three heat dissipation methods of battery modules are studied,and the basic theory of phase change cooling and heat dissipation methods and the solidification\melting module dedicated to phase change cooling simulation in Fluent are discussed in detail.The simulation results effectively verify the heat dissipation effect of the phase change material on the battery module in the natural environment: the temperature field uniformity of the battery module is ensured during low-rate discharge,and the overall battery cell module is 6 °C lower than the phase-change-free material module at high magnification.