
Battery Management Systems for Hybrid Electric Vehicles and Electric Vehicles 31-11
31.4.6.1 Why Batteries Need to Be Balanced
Balancing is the most important concept concerning the life of the battery system because without the
balancing system, the individual cell voltages dri apart over time. e capacity of the total pack also
decreases more quickly during operation, which results in the failure of the total battery system. is
condition is especially severe when the battery has a long string of cells (high-voltage battery systems)
and frequent regenerative braking (charging) is done via the battery pack.
Imbalance of cells in battery sy ...