Lithium-Ion Battery Management Systems

Batteries play an important role in our daily life and many high power applications such as satellite, electric vehicle and hybrid electric vehicles. Lithium-ion battery technology is the most recommended technology over other battery technology due to its good energy density, good power rating and charge/discharge efficiency in pulsed energy flow systems. Lithium-ion batteries can produce a cell voltage of 3.2V-3.7V. To produce a voltage of 48V, fifteen lithium-ion battery cells of voltage 3.2V are connected in series. Each battery has different internal resistance because of the manufacturing defect. Due to this total discharging rate increases. This decays the batteries faster. Overcharging and deep discharge of lithium batteries also decays the batteries faster. To overcome this problem a proper battery management system (BMS) is needed. This paper presents different phases of Battery Management System (BMS). The first phase proposed the design and developed the primary BMS with passive components, which is to maintain the voltage in all cells. In the second phase, a model of the active BMS with TL431 ICs was designed and developed, which regulates the voltage over the batteries. In the third phase, a modified active BMS was designed and developed, which controls the charge level of the battery i.e. an almost fully-integrated active charge equalizer.