Fast Charging of Lithium ion Batteries using Constant Voltage & Constant Temperature Method

Abstract

Abstract Current charging techniques for lithium-ion batteries use a predominantly open-loop strategy, where the charging profile is defined on the basis of a prior knowledge of cell parameters. With the given CC-CV method where temperature has no effect, a new method which uses Voltage and Temperature values to modulate the current value is needed. This paper tackles this gap by proposing a constant temperature constant voltage (CTCV) charging technique, which considers cell temperature as a key degradation metric. The proposed CT-CV charging method uses a simple (PID) controller with feed-forward support. The charging current is dynamically modified in response to the temperature of the battery, which implicitly represents its aging and thermal environment. As per recent tests, the proposed method would result in a 20 percent faster charging at the same total temperature rise as the constant-current constant-voltage (CCCV) technique. Conversely, the change in cell temperature is 20 percent smaller, despite the total charge time. It can easily satisfy applications that need even faster charging by simply increasing the set temperature. This paper points out the advantages of the proposed cell-level charging of CTCV and increases the prospect of expanding it to the pack level by incorporating it into the battery management systems