Study on the Effect of High Temperature and High-Current Rate on Fast Charging of Lithium-ion Batteries

A convenient and fast charging method is key to promote the development of electric vehicles (EVs). High current rate can improve the charging speed, nevertheless leading to more lithium plating. Increasing battery temperature can reduce the lithium plating caused by high rate charging, which benefits cell life. This paper delineates the behavior of lithium-ion batteries at high temperature and high current rate through the model analysis and experiments verification. The first-order equivalent circuit model of battery is used to analyze the variables that affect the charging process. The effect of temperatures and current rates on internal resistance is discussed. The variation law of internal resistance with the temperature and current rate is revealed. Experiments are applied against the 2.2Ah cylindrical ternary lithium batteries in different temperature ranges (25°C-55°C) and charging rates (1C-6C). Charging results demonstrate that high temperature and high current rate have dramatic effects on the fast charging performance of batteries. Charging the battery at 55°C and 6C can significantly improve the charging speed.