Thermal Performance And Inconsistency Analysis Of The Liquid-cooled Thermal Management System For Cylindrical Battery Module

The transportation is an important source of fossil energy consumption and environmental pollution.Accelerating the electrification of transportation is an important measure to achieve the goal of reaching the carbon peak and solve environmental pollution problems such as haze and greenhouse effect.As the main component of new energy vehicles,the battery pack is a core component of electric vehicles.The electrochemical reaction and side reaction in the process of charge and discharge of lithium ion battery show obvious temperature dependence.The reliable thermal management system is the key to ensure the performance of the battery and prolong its service life,and has become a research hotspot in recent years.The electrochemical-thermal coupling model of cylindrical lithium ion battery was established in the COMSOL simulation environment.The battery terminal voltage and temperature were calculated and compared with the experimental results.The results showed that the simulation results were in good agreement with the experimental values.The electrochemical-thermal coupling model of cylindrical lithium ion battery can accurately predict the electrical and thermal properties of the battery,and can be used for subsequent numerical simulation research.The liquidcooled structure of cylindrical lithium-ion battery module was designed.The temperature distribution of the battery module under different working conditions is simulated and analyzed in COMSOL.The maximum temperature of battery pack and the maximum temperature difference of battery module were set as evaluation indexes to quantify the sensitivity of thermal performance of the liquid-based thermal management system under different discharge rate,ambient temperature,mass velocity and inlet temperature.The simulation results provide a reference for the design and optimization of the efficient thermal management system.The electrochemical-thermal coupling model at the module level of an 8P2S liquid-cooled battery module was developed.Based on this model,the influence of connection topology,connection resistance and cooling structure on current distribution,temperature distribution and released energy distribution of the battery pack are obtained.The influence of connection topology on the consistency of the battery pack was analyzed,including Inlet-layout,Outlet-layout and Cross-layout.The results show that Cross-layout is most beneficial to improve the consistency of battery pack and maximize the performance of battery pack.The influence of the connection resistance on the performance of the battery pack was analyzed.It was shown that the discharge consistency of the battery pack deteriorated with the increase of the connection resistance.It was pointed out that the connection resistance between the batteries should be reduced Finally,the effect of the contact angle increment of the heat conduction block on the consistency of the battery pack was obtained.Within the variation range of the contact angle of the thermal conductive block,the electrical performance of the battery pack was almost not affected by the change of the contact angle.However,the temperature uniformity of the battery module was significantly improved with the increase of the contact angle increment of the thermal conductive block.The research work in this paper was mainly based on the simulation of the thermal management system of cylindrical battery module.The electrochemicalthermal models from the cell level to the module level were established.The sensitivity of the thermal management system to different influencing factors was obtained.The designs of the high-efficiency liquid-based thermal management system for the cylindrical battery were supported from multiple levels and angles.