Atmel Introduces First Solution to Support Active Cell Balancing in High-cell-count Li-Ion Battery Packs

The advantage of an active cell balancing is that it avoids the energy loss as occurs with passive balancing methods. The charge is transferred with a shuffle capacitor or inductor from one cell to another with nearly no losses, leading to higher efficiency and a longer battery life. In passive methods, cells of large battery stacks are balanced by discharging overcharged cells through a resistor.

In a typical battery pack, no cell is identical to another. The cells differ in the state-of-charge, self-discharge rate, cell impedance and capacity, and aging. After several charge and discharge cycles, this may result in increased voltage differences between the individual cells. This effect will impact the cells where several cells may no longer be properly charged, with the possibility of weak cells being over or undercharged. This will decrease the overall lifetime of a battery. Active balancing is a perfect method to constantly ensure that all the cells have the same state-of-charge.

Battery efficiency and lifetime are key elements for industrial and automotive battery applications, said Claus Mochel, Automotive High-Voltage Marketing Manager of Atmel Corporation. Atmel's ATA6870 addresses these issues by offering a battery management solution with a superb active balancing technique.