基于电化学阻抗谱的锂离子电池析锂检测方法

The EIS-Ohm method and the EIS-SEI method were proposed based on the variation tendency of electrochemical impedance spectroscopy (EIS) in different temperatures for the lithium ion batteries with and without lithium plating, and the equivalent circuit model was applied to fit the Ohmic impedance and the solid-electrolyte interface impedance in the EIS respectively. With temperature increase, the EIS of the lithium plating batteries showed an increase and then a decrease in Ohmic impedance, while the impedance at the solid-electrolyte interface showed a smaller change. Scanning electron microscopy (SEM) and chemical methods were used to determine the morphology and chemical transformation of the plating lithium metal from the electrode surface. The feasibility of two lithium identification methods was discussed by combining the operating temperature (-10~60 °C) and detection time (> 21 min) of the battery. The results show that the two detection methods developed based on electrochemical impedance spectroscopy can clearly identify the lithium plating, and the rapid, non-dissembling identification methods have important applications for battery life and safety management.