Voltage Relaxation to Detect the Onset of Lithium Plating on Graphite for Fast Charging

Abstract

Li-ion battery fast charging is critical to reduce electric vehicle ‘range anxiety’ and enable emerging technologies such as aerial drones and high-performance portable electronics. Fast charging is primarily limited by lithium plating on graphite, which can cause capacity fade and catastrophic cell shorting. The ability to detect the initial onset of lithium plating using easily accessible battery management system parameters (current, voltage, and capacity) would dramatically improve the safety of fast charging protocols. In this work, we highlight the application of a differential open-circuit voltage analysis (dOCV) to detect when Li plating first begins during room temperature fast charging. We quantify the Li detection limit of the technique to be approximately 4 mAh plated Li per gram graphite, showing that this method has high sensitivity and significant commercial promise.

Modeling of Lithium Plating and Stripping Dynamics during Fast Charging

“…It should be noted that while the plateau in the voltage profile during relaxation is commonly assessed in the literature as an indicator of Li-stripping [22,28,[32][33][34], the peak in the applied current during the CV phase under very low currents is a novel indicator of stripping in this study. The presence of a plating-to-stripping transition during CV charging is strongly dependent on the parameters of the CC-CV charge profiles.…”