Study On Simulation Of Temperature Field In Railway Transport Power Lithium-ion Battery

With the implementation of the " double carbon " strategy and the optimization and adjustment of the transportation structure,container transportation and new energy automobile industry have developed rapidly.The transportation environment of the railway determines that mechanical abuse and heat abuse are the main inducing factors for the thermal runaway of the battery.Among them,the high temperature environment contained in heat abuse is a safety problem that has always existed in the process of railway transportation.Therefore,under the premise of considering the characteristics and packaging conditions of the power lithium battery,the transient thermal analysis method is used to numerically analyze the temperature field of the container,the whole cargo of the power lithium battery in the container,the single package in the high temperature zone and the different loading schemes in the static scene.It is of practical significance to study the feasibility,transportation requirements and transportation conditions of railway container transportation of power lithium batteries,and it is also an urgent problem to be solved.The research contents of this paper are as follows :(1)According to the national standards,industry standards and other contents,the technical conditions and safety requirements of railway transportation power lithium battery transportation equipment and facilities,packaging conditions and other technical conditions and safety requirements are systematically studied,and the risk factors of container transportation lithium battery are analyzed in detail.Based on the theory of heat transfer,the temperature influence model of container and power lithium battery packaging is constructed,and the temperature influence factors and heat transfer process of container and container goods in the yard are analyzed.(2)Based on the HOTTLE solar radiation model and the basic theory of heat transfer,combined with the railway container transportation conditions and the basic characteristics of the power lithium battery,the finite element method is used to analyze the single package in the overall and local high temperature zone of the power lithium battery cargo in the container.The results show that the temperature of the cargo in the container is mainly affected by the heat conduction from the yard ground to the container floor.The high temperature zone of the power lithium battery cargo is mainly concentrated in the underlying cargo.The temperature of the battery pack in the package will increase as a whole in the high temperature environment,and the maximum temperature that can be reached on the packaging surface is40.227℃.The maximum temperature of the battery pack is 35.984℃.It is much lower than the thermal runaway temperature(90 ℃-120 ℃)and the high temperature experimental temperature(75±2℃)in UN38.3.The container can be used as a carrier for power lithium batteries and the high temperature environment in the container will not affect its transportation safety,and the temperature experiment content in UN38.3 is suitable for power lithium battery cargo transported by railway in southern cities.(3)Based on the temperature variation law and high temperature zone distribution of the power lithium battery goods in the box,the finite element analysis of the power lithium battery packaging under different loading schemes is carried out.The results show that in terms of stacking height,the stacking height of the power lithium battery in the box mainly affects the temperature distribution of the upper layer goods and the middle layer goods.The temperature changes on the upper surface,front and side of the goods tend to decrease with the increase of stacking height,and the heating rate is faster and the temperature is higher when loading close to the inner wall of the container.In terms of stacking method,the temperature of goods on both sides of the longitudinal three-body stacking is higher than that of the integrated stacking,but the variation trend of high,medium and low temperature regions and the distribution characteristics of high temperature regions of the two stacking methods are similar.