城轨动力电池系统的安全评估与优化设计

Safety Assessment and Optimization of Power-Battery-Equipped Traction System for Urban Rail Transit

针对目前城轨动力电池缺少相关产品标准,特别是缺乏对其可靠性与安全性的分析评估,以动力电池牵引系统发生安全事故为顶层事件建立了故障树模型,并对事故发生的概率进行了计算与分析,结果显示电芯老化造成的内部短路,电池过充电以及连接器虚接是造成系统安全的3大隐患。并针对这3个问题提出了优化方法,特别是针对电芯老化造成的内部短路,设计了一种更加高效准确的失效检测方法,该方法不仅减少了失效检测的时间成本,也使得测试更加接近于实际工况,最后通过对比优化前后事故发生的概率验证了优化的正确性与必要性。

Given the absence of dedicated standards for the power-battery-equipped traction system for urban rail transit,in particular those on reliability and safety,the paper builds the corresponding fault tree model where safety-related incidents are considered as top events.Based on the probability calculation of incident occurrence,the paper concludes the three main safety concerns,namely internal short circuit induced by cell aging,battery overcharge and poor or loose contact of connector.Methods for optimization are then proposed accordingly.Special attention is given to the internal short circuit caused by cell aging where an effective and accurate approach for fault inspection is designed.The new approach helps to cut the inspection time and ensure that the battery’s working state amid inspection is very similar to that amid actual operation.Afterwards,the paper verifies the effectiveness and the necessities of the upgrade of the safety performance by comparing the corresponding incident probabilities before and after the optimization.