纯电动汽车锂离子动力电池热特性研究

Research of the thermal characteristics of EVs lithium-ion power battery

分析锂离子动力电池的发热机理,总结出电池发热与电动势温度系数、电池荷电状态(SOC)值、电池内阻、电流倍率等因素有关,通过实验在不同环境温度下对三元锂离子电池重要特性指标进行研究。得出结论:放电容量随环境温度的升高而增大,随放电倍率的增大而降低;直流内阻在低温时升高明显,放电内阻大于充电内阻;在低温下荷电状态-开路电压曲线低于高温下曲线;放电效率曲线得出电池正常工作的温度参考范围。对于电动汽车电池热管理系统的设计具有重要的意义。

The heat generation mechanism of lithium-ion power battery was analyzed. It was concluded that the battery heating was related to the SOC of the battery, the resistance of the battery and the current ratio. Based on the experiment, the important characteristic of the NCM were studied at different ambient temperatures. Experimental results are as follows. The discharge capacity increases with the increase of ambient temperature, and decreases with the increase of discharge ratio. The battery resistance rises obviously at low temperature, and discharge resistance is greater than the charging resistance. The SOC-OCV curve in the low temperature is lower than in the high temperature. The discharge efficiency curve gave the temperature reference range for normal operation of the battery. The study provides an important basis for the technology progress of battery thermal management technology for electric vehicles.