Cell balancing is the process of adjusting voltage differences between the cells that make up a battery to equalize them. This is performed by the battery management system (BMS) installed in the pack.
What is a battery energy storage system (BESS)?
Battery energy storage systems (BESSs) are widely utilized in various applications, e.g. electric vehicles, microgrids, and data centres. However, the structure of multiple cell/module/pack BESSs causes a battery imbalance problem that severely affects BESS reliability, capacity utilization, and battery lifespan.
This article has conducted a thorough review of battery cell balancing methods which is essential for EV operation to improve the battery lifespan, increasing driving range and manage safety issues. A brief review on classification based on energy handling methods and control variables is also discussed.
How does a battery balancing system work?
The BMS compares the voltage differences between cells to a predefined threshold voltage, if the voltage difference exceeds the predetermined threshold, it initiates cell balancing, cells with lower voltage within the battery pack are charged using energy from cells with higher voltage (Diao et al., 2018).
What is a battery energy storage system?
Battery energy storage systems (BESSs) have gained significant attention during the past decades, due to low CO 2 emission and the mature development of battery technologies and industry . In order to gain high voltage/capacity, the BESS usually uses multiple low voltage/capacity batteries in series/parallel connections .
Why is battery balancing important?
Due to manufacturing irregularity and different operating conditions, each serially connected cell in the battery pack may get unequal voltage or state of charge (SoC). Without proper cell balancing, serious safety risks such as over-charging and deep discharging in cells may occur.
Can a simple battery balancing scheme reduce individual cell voltage stress?
Individual cell voltage stress has been reduced. This study presented a simple battery balancing scheme in which each cell requires only one switch and one inductor winding. Increase the overall reliability and safety of the individual cells. 6.1.