Charge control apparatus capable of high speed cell balancing and energy saving and method thereof

A charge control apparatus for controlling charging of a high voltage battery including first to nth battery cells connected in series, the charge control apparatus comprising:

• first to nth discharge circuits connected respectively to the first to nth battery cells;
• a high voltage charge line through which high voltage charging power is applied to the first battery cell and the nth battery cell, the high voltage charge line including a high voltage charge switch unit;
• a supplemental charge line through which low voltage charging power is applied;
• first to nth supplemental charge switch circuits connected respectively to the first to nth battery cells to selectively connect the supplemental charge line to at least one of the first to nth battery cells;
• and
• a control unit electrically coupled with the high voltage charge switch unit, the first to nth discharge circuits, and the first to nth supplemental charge switch circuits,
• wherein the control unit is configured to:
• (a) calculate a state of charge of the first to nth battery cells,
• (b) turn off the high voltage charge switch unit when at least one of the first to nth battery cells reaches a fully charged state during charging of the first to nth battery cells,
• (c) determine at least one of the first to nth battery cells with lowest state of charge to be a target for supplemental charging and the remaining battery cells to be a target for forced discharging,
• (d) operate the discharge circuit connected to each battery cell determined to be the target for forced discharging to forcedly discharge the corresponding battery cell, and at the same time, operate the supplemental charge switch circuit connected to the battery cell determined to be the target for supplemental charging to connect the corresponding battery cell to the supplemental charge line to supplementally charge the battery cell, and
• (e) when among the battery cells being forcedly discharged, any battery cell with the same state of charge as the battery cell being supplementally charged appears, stop the operation of the discharge circuit connected to the corresponding battery cell and operate the supplemental charge switch circuit connected to the corresponding battery cell.