Lithium ion battery pack charge control device, control method, and lithium ion battery pack system

摘要

PROBLEM TO BE SOLVED: To more appropriately charge a lithium ion secondary battery when the same is used for an assembled battery.SOLUTION: A charge control device for a lithium ion battery pack comprises: voltmeters 4 to monitor charging voltage of each lithium ion cell 2; balance circuits 3 which are installed on each lithium ion cell 2 and individually discharges the same; and a controller 6 which activates, when the charging voltage of one portion of the lithium ion cells 2 is lower than a lower limit voltage of an appropriate charging voltage range and the charging voltage of the other portion of the lithium ion cells 2 continues to be in a state higher than the lower limit voltage for a predetermined period, the balance circuits 3 for a portion of the other lithium ion cells 2.