Thermal reliability assessment and sensitivity analysis of 18,650 cylindrical lithium-ion battery

Abstract

In order to solve the problems of thermal safety and thermal reliability of the battery, a method of thermal reliability assessment and reliability sensitivity analysis for an 18,650 cylindrical lithium-ion battery is proposed. The finite element analysis (FEA) software is used to establish an electrochemical-thermal coupling model of the lithium-ion battery. By comparing the expected and experimental results, the accuracy of the proposed model is verified, and the model is subsequently used to analyze the thermal reliability. The adaptive Kriging method is used to establish the thermal reliability performance function model and assess the thermal reliability of the lithium-ion battery. Additionally, in order to study the influence of the material parameters on the thermal reliability of the battery, gradual reliability and reliability sensitivity analyses are conducted. The results show that when the density is 3150 kg/m3, the reliability reaches 0.993, which is 14.4 % higher than that of the existing battery, while the sensitivity value decreases. When the specific heat capacity is 1310 J/kg·K, the reliability of the battery reaches 0.986, which is 13.6 % higher than that of the existing battery, while the sensitivity value decreases. Lastly, the thermal conductivity has little influence on the thermal reliability of the battery.