软包锂离子电池应力特性及其建模

Stress Properties and Modeling of Lithium-ion Pouch Batteries

摘要:

锂离子电池是一个电-热-力耦合系统，对其充放电过程中力学特性的研究有重要意义。通过位移式应力传感器，测量并分析了软包单体锂离子电池在不同状态下的静态应力以及不同充放电电流下的动态应力特性。研究了电流、荷电状态、历史运行工况等因素对电池应力变化的影响规律，并通过拟合优度分析和相关性检验，建立了可靠的应力特性多元回归模型。研究表明，静态应力与电池SOC有单调对应关系；动态应力产生于充放电过程，且充电电流越大，动态应力越大。所建立的电池应力模型可较好地描述电池在充电不同阶段、不同电流下的应力变化。

Abstract:

Lithium-ion battery is an electro-thermo-mechanical coupling system. It is of great significance to study the mechanical properties during the charging and discharging processes. According to Linear Variable Differential Transformer (LVDT), the static stress properties at different states and the dynamic stress properties under different charging and discharging currents of single-cell Lithium-ion pouch battery are measured and analyzed. The effects of current, state of charge, historical operating conditions and other factors on the stress change of the battery are studied. Through goodness analysis of fit test and significance validation, a reliable multivariate regression model of stress properties is established. The research shows that there is a monotonous relationship between static stress and state of charge; dynamic stress is generated during the charging and discharging process, and as the charging current becomes larger, the dynamic stress will increase accordingly. The established battery stress model can well describe the stress changes of the battery at different charging phases and under different currents.