An Overview of Active cell Balancing Electronic devices often use multiple cells connected in series for powering the applications. Each battery in the battery pack tends to age differently because of operating conditions and production tolerances. It causes an imbalance between the cells of the battery packs. If these differences are not taken care of using an equalizer, the battery pack cannot work to its full capacity, and its safety is also compromised. Such a situation is avoided through balancing. What is balancing? When cells are out of balance the battery pack cannot accept or deliver power. In the initial stages, the weak cell limits the whole pack's performance and renders the battery pack useless if it continues without balancing. Balancing ensures that the SoC (State of Charge) of each battery in the cell is the same by managing the charge distribution. It helps in protecting the cells when they operate out of the bounds of normal operating conditions. There are two types of balancing - passive and active. Passive balancing expends charge from batteries having too much charge and disperses bleeding energy as heat. It is a simple and inexpensive process but not as efficient as active balancing. Active balancing works by moving the charge from high voltage cells to the low voltage cells. Why Is Active Balancing Necessary? Without a balancer, after each charge and discharge, the differences between battery parameters are magnified, leading to quick deterioration of the battery packs. The whole battery can fail prematurely or become weaker due to the overstress it experiences because of these differences. However, by equalizing the charge in the battery chain using active balancing, it is possible to extend the battery life. Active balancing prevents battery damage, allows optimal battery usage, and provides overcharge protection. The circuits related to this arrangement are implemented either in the battery or the charger. Lithium ion battery chemistries work more efficiently using active balancing techniques than passive types.