纯电动车用18650电池的一致性研究

Consistency study on 18650 cells used in electric vehicles

  • 摘要: 通过对国内外五款纯电动车用18650电池进行电化学性能测试、变异系数分析和相关性分析,评估电池在初始阶段和老化过程中的一致性,并系统分析电流、温度及电压范围对电池一致性的影响.结果表明:为了提高纯电动车用18650电池全寿命周期内的一致性,必须控制充电倍率小于0.3C,放电倍率小于0.5C,使用温度高于0℃.此外,优化电池筛选工艺也是改善电池一致性的一个重要方法.初始筛选时加入能够表征寿命因素的特征参数k值,即静置时开路电压的下降速率,是非常有效的.

     

    Abstract: The consistency of five different 18650 cells used in electric vehicles both at the initial and aged states was evaluated by electrochemical test and statistical analysis. The effects of current, temperature and voltage on the cell consistency were examined. The results show that, to ensure a reasonable level of the cell consistency, the current rates during the charging and discharging processes should be less than 0.3C and 0.5C, respectively, and the operating temperature should be higher than 0℃. In addition, the cell sorting process is crucial to control the cell consistency. An additional descriptor, the k value, representing the decreasing rate of open circuit voltage during calendar test, should be involved in the cell sorting.

     

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