The powertrain system is critical to the reliability of a battery electric vehicle (BEV). However, the BEV powertrain is a complex system; it includes the motor, motor controller, power distribution unit, battery system, etc. The failure of any of these components may result in the failure of the entire powertrain system and eventually cause serious traffic accidents on the road. However, how much does each component affect the reliability of the entire system, and which components are the most vulnerable in the entire system? These questions are still unanswered today. To develop a reliability design for a BEV powertrain system, it is essential to conduct detailed research by investigating the most vulnerable component parts of the entire powertrain. In the present study, a fault-tree model of the entire powertrain and its subsystems was developed. Based on this model, the failure rates of all components were calculated first. Then, trends in the reliability indices for the entire powertrain and its components were estimated against BEV service life. From the estimation results, we learned that with increased service time, the reliability of the entire powertrain system is indeed much lower than that of its individual subsystems. Moreover, through comparative research, we found that the battery module is the most unreliable component not only of the battery system, but the entire powertrain system. Additionally, it was interesting to find that the reliability of the motor components was higher than that of other subsystem components, but that the reliability indices for the entire motor were not the highest among all the powertrain subsystems studied in this paper. We believe the findings of the present study will be of great significance to an improved understanding of the reliability design and maintenance of BEVs.

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BEV动力总成系统及其组件的可靠性研究—案例研究

动力总成系统对于电池电动汽车（BEV）的可靠性至关重要。但是，BEV动力总成是一个复杂的系统。它包括电动机，电动机控制器，配电单元，电池系统等。任何这些组件的故障都可能导致整个动力总成系统发生故障，并最终在道路上造成严重的交通事故。但是，每个组件对整个系统的可靠性有多大影响？哪些组件在整个系统中最易受攻击？这些问题至今仍未得到解答。为了开发BEV动力总成系统的可靠性设计，必须通过研究整个动力总成中最易损坏的零部件来进行详细的研究。在目前的研究中，建立了整个动力总成及其子系统的故障树模型。基于此模型，首先计算所有组件的故障率。然后，根据BEV使用寿命估算了整个动力总成及其组件的可靠性指标趋势。从估算结果中，我们了解到，随着服务时间的增加，整个动力总成系统的可靠性确实比其各个子系统的可靠性要低得多。此外，通过比较研究，我们发现电池模块不仅是电池系统中最不可靠的组件，而且是整个动力总成系统中最不可靠的组件。此外，有趣的是发现电机组件的可靠性高于其他子系统组件的可靠性，但是在本文研究的所有动力总成子系统中，整个电动机的可靠性指标并不是最高的。我们认为，本研究的结果对增进对BEV的可靠性设计和维护的理解具有重要意义。