Model Development of Charge Equalization Controller for Lithium-Ion Battery

The concept of electric vehicle (EV) has been developing as efficient and environ-friendly transportation by powering lithium-ion (li-ion) battery now-a-days. Although secondary li-ion batteries are highly attractive in EV energy storage application for their worthwhile features, their performances are degraded due to overcharge, undercharge and unequalization conditions when they are experienced with a number of charge-discharge cycles. To enhance the performance and to prevent the anomalies, the model development of charge equalization controller is necessary. This paper deals with the development of charge equalization controller model for li-ion battery with simple design and control using a bidirectional flyback DC-DC converter that protects the battery, and equalizes the batteries in series stack. The equalization results show the perfect equalization of battery with 15% SOC difference for overcharged and undercharged conditions.