Electrochemical Techniques to Detect and Quantify Li Plating after Fast Charge of Li-Ion Batteries

摘要

Despite electric vehicles (EVs) gaining a small foothold in the light vehicle market, long charging times and battery safety have been key limitations in EV's general acceptance. In commercial Li-ion batteries, fast charging is limited by the deposition of metallic lithium on graphite, or 'Li plating', which can cause capacity fade and catastrophic cell shorting. The ability to detect plating on-line in vehicles is critical to allow faster charging while maintaining safety standards. Analyzing the cell voltage relaxation after charge is a promising approach for in-situ Li detection. Plated Li can insert into the graphite at rest, which gives a dV/dt feature unique to plating. Our work shows that voltage relaxation can be used to detect small quantities of Li plating immediately after battery charging at any charge rate, including those relevant for fast charging.