A reliability study of electric vehicle battery from the perspective of power supply system

Battery cells and modules are critical to the reliability of the power supply system of an EV. Therefore, their reliability is mainly concern before. However, EV's power supply system is a complex system. Besides battery cells and modules, it also includes many other components, the failure of which can cause a breakdown of the system as well. So, the reliability of the battery should be evaluated from the perspective of the entire power supply system rather than only considering the reliability of the battery cells and modules. This motivates the research of this paper. In the present study, the failure rates of all major components are predicted first. Then, based on the prediction results, the reliability of the entire battery system is assessed. From the assessment results, it is found that the reliability of the entire battery system is indeed much lower than those of individual components including battery modules. Moreover, as compared to the degradation of individual components, the entire system degrades more rapidly over time. Additionally, it is interestingly found that the Battery Management System (BMS) controller is not as reliable as the battery modules in the battery system considered in this paper.