车用锂离子电池液冷式热管理系统实验研究

锂离子电池组的热管理对电动汽车的性能和安全性具有重要意义。基于多通道蛇形波纹管液冷式热管理系统,以200个18650型锂离子电池组为热管理对象,对电池在各种充放电倍率下所需的冷却液流量、泵功消耗以及热管理收益进行了实验研究。结果表明,热管理系统对动力电池在各种充放电应用条件下都具有较好的热管理效果,电池最大温度和最大温差基本可控制在40℃以下和5℃以内。提高冷却水流速对系统热管理能力的提升具有一定的效果,但是随着流速增大,热管理能力提升的边际效益也更趋明显;而系统运行所消耗的泵功增加导致了热管理收益随冷却水流速增加而大幅降低。从电池的性能安全以及热管理有效性的角度综合考虑,各充放电倍率下热管理系统的冷却水流速都是以保证电池安全和性能指标的最低流速为优。

Experimental Study on Liquid Cooling Thermal Management System of Lithium-Ion Battery for Electric Vehicles

The thermal management of the lithium-ion battery packs is crucial for keeping the temperature below the security limits and enhancing the system performance of the electric vehicles. In this paper, a comprehensive thermal analysis of a 18650-type lithium-ion battery pack that consists of 200 cells was experimentally conducted using a multi-channel liquid cooling system with a serpentine wavy configuration. The capability of the proposed cooling system was investigated under different coolant flow rates and pumping power for various charge/discharge conditions. The results showed that the proposed cooling system was effective, the battery pack temperature was kept below 40^oC under various charging and discharging conditions and achieved a maximum temperature difference of 5^oC for most of the tested conditions. It was found that increasing the coolant flow rate can enhance the thermal management capability of the system, but using high coolant flow rate may not likely lead to considerable improvements when considered in cost/benefit analysis. On the other hand, the increment of pumping power was shown to cause a significant decrease in the thermal performance of the battery pack. Therefore, it was concluded that the optimum coolant flow rate was the minimum value that was large enough to ensure the battery safety and deliver optimum performance.