Lithium-ion Battery - Battery Charging Procedure

Battery Charging Procedure

The charging procedures for single Li-ion cells, and complete Li-ion batteries, are slightly different.

• A single Li-ion cell is charged in 2 stages:

1. CC
2. CV

• A Li-ion battery (a set of Li-ion cells in series) is charged in 3 stages:

1. CC
2. Balance (not required once a battery is balanced)
3. CV

Stage 1: CC: Apply charging current to the battery, until the voltage limit per cell is reached.

Stage 2: Balance: Reduce the charging current (or cycle the charging on and off to reduce the average current) while the State Of Charge of individual cells is balanced by a balancing circuit, until the battery is balanced.

Stage 3: CV: Apply a voltage equal to the maximum cell voltage times the number of cells in series to the battery, as the current gradually declines asymptotically towards 0, until the current is below a set threshold of about 3% of initial constant charge current.