基于电化学阻抗谱的电芯内部温度估计研究

Estimation of internal battery temperature based on electrochemical impedance spectroscopy

锂离子电池在新能源汽车和储能领域的广泛运用带来了内部状态估计方面的挑战,尤其是电芯内部温度的准确估计,这对于电池的热失控预警至关重要。本文回顾了经典的无传感器电池温度检测方法,介绍了目前采用的基于电化学阻抗谱(EIS)的温度估计方法,研究了电池内部参数对EIS估算温度的影响,分析了大容量三元锂离子动力电池在不同频率下阻抗幅值、相角与温度之间的关系,提出了一种基于电化学阻抗谱的锂离子电池在线温度估计模型,通过分析不同频率下的阻抗幅值、相角与温度的关系,实现了对电池内部温度的准确估计。研究表明适合使用阻抗幅值信息来估算温度的频率点为10 Hz,适合使用阻抗相角信息来估算温度的频率点为17.5 Hz。该模型在-20℃到45℃的范围内,使用阻抗幅值进行温度估算的最大误差为3.79℃,使用阻抗相角信息进行温度估算的最大误差为2.69℃。验证结果表明,使用阻抗谱的幅值与相角信息能有效估算电池内部的真实温度。本研究有助于提升汽车BMS的采集功能,可用于改善电池热管理和热失控的管理策略。

The widespread application of lithium-ion batteries in new energy vehicles and energy storage presents challenges in accurately estimating their internal states,particularly the temperature within the battery core,which is crucial for thermal runaway prediction.This paper reviews classical sensor-less methods for battery temperature detection and introduces a temperature estimation approach based on electrochemical impedance spectroscopy(EIS).Moreover,this study investigates the influence of internal battery parameters on temperature estimation using EIS and analyzes the relationship between impedance magnitude,phase angle,and temperature for high-capacity ternary lithium-ion power batteries at different frequencies.A model for the online temperature estimation of lithium-ion batteries based on EIS is proposed,which achieves an accurate estimation of the internal battery temperature by analyzing the relationship between the magnitude of the impedance,phase angle,and temperature at different frequencies.The study indicates that a frequency point of 10 Hz is suitable for estimating temperature using impedance magnitude information,while a frequency point of 17.5 Hz is suitable for estimating temperature using impedance phase angle information.Within the range of-20℃to 45℃,the maximum temperature estimation errors obtained when using the impedance magnitude and impedance phase angle are 3.79℃and 2.69℃,respectively.Validation results demonstrate that the use of the impedance spectrum magnitude and phase angle information effectively estimates the true internal temperature of the battery.This study helps to improve the acquisition function of automotive BMS,which can be used to improve the management strategy of battery thermal management and thermal runaway.