White Paper - The 3 charging stages

Charging a Pack with a CCCV charger and a BMS

Fully chanrging a Li-Ion battery pack with a CCCV (Constant Current / Constant Voltage) charger and a BMS requires three stages

1. Full charge: charger is fully on (CC), until a cell reaches its maximum voltage
2. Balance: charger goes off and on (CC), while BMS balances the cells, until all cells reach 100 % SOC
3. Top off: charger stays on (CV), while the current is reduced exponentially down to 0

The Constant Voltage of the charger must be set to CV = number of cells in series x max cell voltage.

For more details, please see FIGURE 6.26 and section 6.2.3 of the book Battery Management Systems for Large Lithium-Ion Battery Packs .