锂电池内部温度与单频率相位角相关性研究

Study on correlation between internal temperature and single frequency phase angle of lithiumion batteries

热失控作为锂离子电池的失效方式之一,如何对其早期预警成为目前关注的焦点。通过对锂离子电池在恒温静置与单边受热状态下进行实验,验证锂离子电池内部温度与单频率相位角的相关性。结果表明:在30~60℃范围内,锂离子电池相位角随其内部温度的升高而单调增加;以二项式为回归方程,基于最小二乘算法对在低频(5 Hz)至高频(500Hz)范围内的相位角与电池内部温度进行拟合,发现二者均具有良好的拟合优度。选取5 Hz相位角进行单边加热实验,发现无论在恒温静置还是单边加热状态下,单频率相位角与电池内部温度均存在二阶线性关系。该研究结果及实验方法对开发交流阻抗实时监测电池温度技术具有重要的实际意义。

Thermal runaway is one of the failure modes of lithium ion batteries.The correlation between the internal temperature of lithium ion battery and the phase angle of single frequency was verified by experiments under the condition of constant temperature standing and unilateral heating.The results show that the phase angle of lithium ion battery increases monotonically with the increase of internal temperature in the range of 30-60 ℃.The binomial regression equation was used to fit the phase angle and the internal temperature of the battery in the range from low frequency(5 Hz) to high frequency(500 Hz) based on the least square algorithm.A phase angle of 5 Hz was selected for unilateral heating experiment.The result shows that there is a second-order linear relationship between the phase angle of a single frequency and the internal temperature of the battery,no matter in the state of constant temperature standing or unilateral heating.The research results and experimental methods are of great practical significance for the development of AC impedance real-time monitoring battery temperature technology.