基于退化轨迹的锂离子电池加速试验研究

Study of Li-ion Cells Accelerated Test Based on Degradation Path

针对锂离子电池长寿命、高可靠的特点,提出了使用恒定应力加速退化试验对其进行可靠性评估与寿命预测的方法。首先对锂离子电池进行FMEA分析,得出容量衰减是最常见的失效模式,并以温度作为主要的加速应力。其次,确定锂离子电池的加速退化模型和参数退化轨迹模型,并进行锂离子电池的加速退化试验设计。确定加速应力水平时,在锂离子电池参数退化轨迹的基础上,根据巴特利特检验统计量确定退化机理一致的边界应力。最后,基于伪寿命对锂离子电池的可靠性进行评估。

According to the characteristics of long life, high reliability of Li-ion cell, a constant stress accelerated degradation test method was put forward to accesses reliability and predicts life time of Li-ion cell. FMEA analysis was carried out on Li-ion cell regarding capacity reduction as the most common failure mode and using temperature as the most important accelerated stress. The accelerated degradation models and parameters of the degradation path model of Li-ion cell were determined and the accelerated degradation test of Li-ion cell was designed. Degradation mechanism consistency boundary was determined by the Bartlett statistic based on parameter degeneration path and the determined accelerated stress level. The reliability of Li-ion cell was accessed based on pseudo life.