Online detection of lithium plating onset during constant and multistage constant current fast charging for lithium-ion batteries

Lithium plating during the fast charging process significantly decreases the health and safety of lithium-ion batteries (LIBs). Hence, detecting the onset of lithium plating is essential to realize the highly effective and low-damage fast charging. However, an online lithium plating onset detection method that can be used in constant current (CC) and multiage constant current (MCC) fast charging under different working conditions without interrupting the charging process of LIBs has not been reported yet. To fill this gap, a novel method based on dynamic impedance measurement has been proposed. The abnormal drop of dynamic impedance at 1 Hz during the charging processes was treated as a universal feature of lithium plating onset. A method based on real-time impedance feedback and a long short-term memory (LSTM) was first proposed to identify this feature. It was validated in various CC and MCC charging rates at different temperatures and battery types. With the cross-validation of the voltage relaxation method, an error of <2.5% SOC in detecting the lithium plating onset was achieved. Besides, the proposed method effectively optimizes the misidentification and the time delay in detection. For practical applications, the method's accuracy and robustness were additionally validated in a rapid prototyping system. The method proposed in this paper solves the complex problem of lithium plating detection during the CC and MCC charging procedures, which is essential for improving the health and safety of LIBs under fast charging conditions.