Active Cell Balancer Extends Run Time and Lifetime of Large Series-Connected Battery Stacks

October 01, 2013 // By Jim Drew, Linear Technology

cells are charged and discharged as a series stack and the state of charge (SoC) of each cell depends on its ability to store and maintain charge. Treating the cell stack as a single battery composed of capacity-matched cells can work well in the short term, but becomes increasingly inefficient in the long run.

Large stacks of series-connected battery cells are increasingly used to power electric vehicles or store energy in wind and solar power systems. It is not uncommon to have 100 cells connected in series in an electric vehicle, and even more in energy storage units for alternative energy systems. Typically, the stack is treated by the charge-discharge system as a single battery—
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