Performance Analysis And Heat Dissipation Optimization Of Lithium-ion Batteries For Electric Vehicles

Under the dual pressure of declining fossil energy storage and environmental degradation,traditional internal combustion engine vehicles are forced to transform to new energy,among which the exploration of electric vehicles has attracted much attention.As the core driving energy of electric vehicles,power batteries have developed by leaps and bounds,which brings a problem that cannot be ignored-the thermal safety of batteries.The high density and high specific energy of the battery will inevitably make it produce a lot of heat during the working process,and if there is a lack of good heat dissipation conditions,it will lead to a decline in battery performance,shorten the life,and thermal runaway in serious cases,which has a serious threat.This paper takes a domestic 55 Ah LFP battery as the research object,and conducts the following research on its thermal characteristics and heat dissipation system:1.The basic structural principle and heat generation principle of lithium iron phosphate battery are described,and then the thermal performance test of the lithium-ion battery is carried out,mainly analyzing its voltage,capacity retention rate and internal resistance under different ambient temperatures,and testing the temperature change of the battery under different discharge rates,so as to provide support for the model establishment and simulation of subsequent batteries.2.Three-dimensional modeling of lithium-ion batteries,using the battery data obtained from the test,combined with the experience-based electrochemical model for simulation and solving,the temperature field of the battery is obtained,and the test results are compared.Next,ADVISOR software is used to simulate the heat generation of the battery under several different driving conditions,which provides a reference for the subsequent design of a reasonable heat dissipation model.3.Taking the traditional serpentine lithium-ion battery liquid cold plate as the analysis object,taking the highest temperature and maximum temperature difference as the most evaluation standard,three different structures are designed and compared with it,and the best liquid cold plate design scheme is obtained.Parameter optimization for the best liquid cold plate designed:(1)The overall parameters(including the width and depth of the internal flow channel of the liquid cold plate,as well as the flow rate and inlet temperature of the coolant)are optimized,and the optimal parameter combination is obtained by orthogonal analysis.(2)Then,the structural parameters of the local structure of the internal flow channel of the liquid cold plate-the fin structure were optimized.4.Test the final results of the designed optimization scheme to verify its reliability and accuracy,and provide a certain reference for the battery heat dissipation design.