US Patent 9627920 Battery pack and charging method thereof

A charging method of a battery and a battery pack thereof are described. A fully charged amount of the battery cell is changed upon comparing the charge amount of the battery to a reference capacity. If the battery cell is fully charged, charging of the battery cell may be interrupted and a counter incremented. The charged amount of the battery cell is compared to a reference capacity, and if the charged amount of the battery cell is equal to the first reference capacity, the fully charged amount of the battery cell may be set to another reference capacity, and the battery discharged the battery cell down to the new reference capacity.