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I have a 3 cell Li-Ion battery connected in series and want to charge them with a single battery charger IC. What I found is BQ24105, a Stand-Alone Battery Charger with following schematic for charging 2 cell battery.
The BQ24105 can handle multicell battery charging as stated in the datasheet. The IC just takes care of the charging of the batteries but assumes that the battery pack (the dashed box in Figure. 1) has all the necessary protection circuit.
A battery pack with multiple batteries in series should have a protection circuit that monitors battery voltage, temperature and current. A balancing circuit is also necessary to monitor each cell in the pack to equalize the voltage for all cells.
Even if you buy the same type of batteries from a single manufacturer, each cell has small variations causing them to charge and discharge differently which makes it necessary to have a balancing circuit.
BQ24105 will not handle cell balancing, But it should be take cared as suggested by Oskar Persson Answer. Note that battery balancing can be implimented passively or using active components.
Fortunately in a system with a fully integrated battery charger(like in my case), circuit comes with a Battery Fuel Gauge IC like BQ40Z50-R2 to measure state of charge(SoC) in the battery pack.
This seems a miracle to me, as these Fuel Gauge IC comes with an integrated battary balancer. So as long as you have a Battery Fuel Gauge in your system, that thing will handle cells balancing for you.
