可变低温环境锂电池组内部短路故障诊断

针对可变低温环境下锂离子电池组易发生的内部短路故障问题，提出基于模型的电池组参数估计和故障诊断方法. 通过特性实验，建立三元锂电池容量与温度的关系. 根据标准-偏差模型，采用无迹卡尔曼滤波实时估计标准电池状态和参数，结合双卡尔曼滤波得到电池组状态和参数的实时估计结果，根据电池容量衰减定量诊断内部短路故障. 在5~25 °C时变温度下，结合实际工况进行电池组充放电实验，通过并联电阻法模拟内部短路故障，得到电池组状态和内部短路电阻估计值和真实值的对比. 实验结果表明，利用提出的方法能够快速、精确地跟踪电池组状态，准确地诊断电池内部短路故障.

Fault diagnosis of internal short circuit of lithium battery pack in variable low temperature environment

A model-based method of parameters estimation and fault diagnosis for lithium-ion battery pack was proposed considering the internal short circuit fault which was easy to occur in lithium-ion battery pack under variable low temperature environment. The relationship between capacity and temperature of lithium-ion battery was established through the characteristic test. The unscented Kalman filter was utilized to estimate state and parameters of standard cell according to the standard-deviation model. The real-time estimation results of battery pack were obtained by double Kalman filter, and the internal short-circuit fault was quantitatively diagnosed depending on the depletion of capacity. The actual driving condition test was conducted on a series-connected battery pack under the time-varying temperature of 5~25 °C, and internal short circuit fault was simulated by the parallel resistance method. The battery state estimation and internal short circuit fault diagnosis results were compared with real value. The experimental results show that the proposed method can precisely track the state of battery pack and accurately diagnose the internal short-circuit fault.