Study On The Safety Evaluation Method Of Railway Dangerous Goods Transportation For Power Lithium Batteries

With the development of new energy vehicles, lithium batteries as the main power source of new energy vehicles, the production and transportation demand increase year by year. According to international regulations, the power lithium batteries of new energy vehicles are dangerous goods and have their own risk, which have always been the focus of international and domestic concerns. However, the power lithium batteries have not yet been transported by rail, and the safety conditions of the railway transportation are not clear. Therefore, it is of great importance that study on the safety evaluation of power lithium batteries transported by rail. The main contents of this paper are as follows:(1) The induction and summary of related theoretical methods of safety evaluation.After study and compare evaluation methods of several papers, this paper introduces the dissipative structure theory and the entropy theory to develop the research on safety evaluation of power lithium batteries transported by rail. Then the dissipative structure theory and entropy theory related to the method of evaluation are discussed, and the dissipative structure and dissipative mechanism of railway transportation system of lithium batteries are analyzed.(2) Construction of safety evaluation index system of lithium battery transported by rail. The paper firstly analyzes the harmfulness of power lithium batteries transported by rail combined with structure of lithium batteries, the physical and chemical properties of lithium batteries and the thermal disaster mechanism mechanism of lithium batteries. Secondly, in view of the risk of lithium batteries, the paper puts forward the safety requirements of technology equipment and carrying tools and packaging, organization conditions of railway transportation, staff training and transportation safety management requirements. Thirdly, in order to determine the safety factors of lithium batteries transported by rial, the paper analyzes the accidents of railway dangerous goods at home and abroad by grey correlation analysis. Finally,according to the analysis results above, the safety evaluation index system of lithium batteries transported by rial was constructed from 5 aspects of "people - machine ?environment - management - goods".(3) The safety entropy is used to evaluate the stability and order of the rail transport system of lithium batteries. Firstly, based on the information entropy, a safety entropy calculation model for lithium batteries transported by rail is established. The probability of the risk of the index is obtained by using the fuzzy mathematics, and the entropy weight-analytic hierarchy process determines the weight of the index. Secondly,the safety entropy can be calculated by the combination of risk membership and weight.Thirdly, the paper builds the fault tree model of lithium batteries transported by rail, and map it to bayesian networks. Buckley method is used to calibrate the prior probabilities of root nodes, and Netica is used to update posterior probabilities of root nodes. Finally,posterior probabilities of root nodes are used to calculate the entropy of the transportation system of the lithium batteries occurred to fire accident for defining the safety state of the system.(4) Example analysis and conclusion. The paper simulates the process of power lithium batteries transported by rail to evaluate its transportation status with selecting a representative railway dangerous goods container handling station and the lithium batteries' information provided by actual company. The evaluation results show that the evaluated system is in a safe state that can guarantee the safe transportation of lithium batteries.