One of the greatest challenges today is in developing economical and effective active cell balancing.   Today various methods of cell balancing are employed, including passive balancing and those labeled as active balancing or dynamic active balancing.  What is needed is a balancing method able to efficiently balance cells in a battery pack throughout entire charge and discharge cycles without energy loss / heat generation. 

The importance of proper cell balancing cannot be overstated.  Operating temperature (even with active cooling) and Coulomb efficiency differs from cell to cell. From the start, cells exhibit initial capacity, impedance and self-discharge differences.

Figure 3: Cells are different prior to being assembled into a battery. Technologies that minimize the impact of these differences in battery operation can reduce manufacturing costs.

Left untreated, cells will eventually be in different States of Charge (SOC), will discharge to different depths, will age at different rates and will eventually fail at different times.  Imbalance grows throughout cell life. 

Sendyne^® is working with the University of Toronto’s Electrical and Computer Engineering Department Laboratory for Power Management and Integrated SMPS for the development of a novel power management system for large-scale storage.

Battery Control
Sendyne’s^® team has extensive experience in Digitally Assisted Analog (DAA) and embedded firmware for the development of microcontroller-based battery management for both the module and total system management of a battery pack.

Quoted from Sendyne company website. For the original article, please refer to Sendyne's website: http://www.sendyne.com//Technology/technology.html