Thermal safety study of Li‐ion batteries under limited overcharge abuse based on coupled electrochemical‐thermal model. (23rd January 2020)

• Record Type: Journal Article
• Authors: Zeng, Ganghui; Bai, Zhonghao; Huang, Peifeng; Wang, Qingsong
• Is Part Of: International journal of energy research. Volume 44:Number 5(2020)
• Page Start: 3607
• Page End: 3625
• Publication Date: 2020-01-23
• Subjects: battery thermal safety -- electrochemical‐thermal coupled model -- Li‐ion battery -- overcharge; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.5125
• Languages: English
• ISSNs: 0363-907X

Abstract

Summary: Many fire accidents of electric vehicles were reported that happened during the charging process. In order to investigate the reasons that lead to this problem, this paper studies the thermal safety of Li‐ion batteries under limited overcharge abuse. A 3D electrochemical‐thermal coupled model is developed for modeling thermal and electrochemical characteristics from normal charge to early overcharge state. This model is validated by experiment at charge rates of 0.5C, 1C, and 2C. The simulation results indicate that irreversible heat contributes most to temperature rise during the normal charge process, but the heat induced by Mn dissolution and Li deposition gradually dominates heat generation in the early overcharge period. Based on this, a threshold selection method for multistage warning of batteries overcharge is proposed. Among them, level 1 should be considered as a critical stage during the early overcharge process due to the deposited lithium starts to react with electrolyte at the end of level 1, where temperature rate increases to 0.5°C min −1 for 1C charge. While the thresholds of levels depend on charge rate and composition of battery. Furthermore, several critical parameters are analyzed to figure out their effects on thermal safety. It is found that the temperature at the end of overcharge is significantly influenced by the change of positive electrode thickness and solid electrolyte interface (SEI) film resistance. The final temperature increases by 17.5°C and 7.9°C, respectively, with positive electrode thickness ranging from 50 to 80 μm and SEI film resistance increasing from 0.002 to 0.03 Ω. Abstract : This paper established a 3D electrochemical‐thermal coupled model to simulating thermal and electrochemical characteristics from normal charging to early overcharge state. This paper proposed a threshold selection method for multistage warning of battery overcharge. Three critical parameters were investigated to figure out their effects on thermal safety during the early overcharge process.