Constant-temperature constant-voltage charging method for lithium-ion battery technology

Abstract

Lithium-ion batteries are the Electrical Vehicles' (EVs) best choice of Energy Storage Systems (ESS) on account of their energy density, power density, and life cycle. In order for the EVs to compete with conventional vehicles, they need faster-charging methods to have equivalent refueling time. However, fast-charging can hamper the life cycle due to higher currents applied to the battery because of the Li-ion battery's uncontrolled temperature increase. This thesis evaluates the Constant-Temperature and Constant-Voltage (CT-CV) charging methodology for three different Li-ion batteries over a temperature range of 0°C-50°C. Similarly, the conventional Constant-Current and Constant-Voltage (CCCV) charging methodology is assessed for comparison. Moreover, a Battery Automated System (BAS) is developed to acquire the charging time, coulombic efficiency, and life cycle. Finally, a model capable of predicting the charging time, battery voltage, and surface temperature is described.