针对目前新能源汽车中圆柱形电池组横向流散热方式存在的主要问题，提出了电池组可采用纵向流散热方式散热，并基于经典对流换热理论对该散热方式进行理论研究。通过计算和分析，该散热方式可以实现无间隙电池组设计，减小了电池间的空隙，有效减小电池组体积，提高体积能量密度，同时保证了良好的均温性能和较高的换热效率。研究表明，纵向流散热方式在提高电池组体积能量密度方面具有明显优势，可通过提高冷却介质流速等措施来优化其散热性能，为后期圆柱形电池组的散热设计和优化提供了理论依据和指导。

In view of the main problems existing in the transverse flow heat dissipation mode of cylindrical battery pack in the new energy vehicle, it was proposed that the longitudinal flow heat dissipation mode could be adopted for the battery pack heat dissipation. Based on the classical convective heat transfer theory, a theoretical study on this heat transfer mode was carried out. Through calculation and analysis, the heat dissipation method could realize the no-gap battery pack design, reduce the gap between the batteries, effectively reduce the battery pack volume, and increase the volume energy density, and meanwhile ensure the good uniform temperature performance and higher heat transfer efficiency. The results show that the longitudinal flow heat dissipation method has obvious advantages in increasing the bulk energy density of battery pack, and the heat dissipation performance can be optimized by increasing the cooling medium flow rate, which provides a theoretical basis and guidance for the heat dissipation design and optimization of cylindrical battery pack.