A programmable charger for monitoring and control of multi-cell lithium-ion batteries

Lithium-Ion batteries are becoming the favorable selection for most portable electronics and more recently electric and hybrid-electric vehicles. This is mainly due to their high energy density and low self-discharge rate. On the other hand, lithium-ion batteries require supervision while charging and discharging to maintain the voltage and current within safe limits. This paper presents a real-time programmable approach to charge lithium-ion batteries with multiple cells. Mathwork´s Simulink environment is used in real-time to control a current source to charge the battery. The control logic monitors the battery cells voltages that are read through an A/D converter and then calculates the desired charging current levels. The proposed system allows engineers and researchers to easily implement and test different lithium ion battery charging methods. Furthermore, the Simulink environment allows real-time monitoring and permits charging profiles to be implemented at ease. The system is demonstrated through two different charging methods. The variations of the charging current and cell voltages are presented and compared, demonstrating the flexibility of the system.