Thermal runaway safety analysis of eVTOL based on evidence theory and interval analysis

基于证据理论和区间分析的eVTOL热失控安全性分析

¹ Key Laboratory of Civil Aircraft Airworthiness Technology, Civil Aviation University of China, Tianjin 300300, China
² Institute of Science and Technology Innovation, Civil Aviation University of China, Tianjin 300300, China
³ Sino-European Institute of Aviation Engineering, Civil Aviation University of China, Tianjin 300300, China

Received: 7 June 2023

Abstract

In order to ensure the safety of eVTOL, safety analysis of thermal runaway problem of lithium battery is needed. Due to insufficient failure data, a safety assessment method based on evidence theory and interval analysis is proposed. Firstly, a fault tree model for system is constructed. Secondly, for the imprecise failure rate of bottom events in fault tree analysis, the failure probability interval of bottom event is calculated by using the evidence theory, and combining with the importance analysis to address the problem of inaccurate failure rate of bottom events in fault tree analysis. The evidence theory is used to calculate the probability interval of failure of bottom events and combine it with interval theory to calculate the top events of the fault tree. Finally, the importance analysis is used to find out the basic events that have the greatest impact on the top events. The proposed method is used to analyze the safety of the eVTOL′s battery thermal runaway and calculate the importance of each bottom event, so as to provide a basis for reducing the system failure probability and improving the system safety level.

摘要

为保证eVTOL的安全性, 需要对锂电池的热失控问题进行安全性分析。针对锂电池热失控失效数据不足这一问题, 提出一种基于证据理论和区间分析的安全性评估方法：对系统进行故障树建模; 针对故障树分析中存在的底事件失效率不精确的问题, 使用证据理论计算底事件失效概率区间, 并结合区间理论对故障树顶事件进行计算; 通过重要度分析, 找出对顶事件影响最大的底事件。利用所提方法, 对eVTOL电池热失控进行安全性分析并计算各底事件的重要度, 从而为降低系统失效概率、提升系统安全性水平提供依据。