Battery pack voltage adjustment device and battery pack voltage adjustment method

摘要

PROBLEM TO BE SOLVED: To prevent overdischarge and overcharge of each unit cell, and make the charging capacity of a combined battery which is constituted by connecting the respective unit cells in series to be not restricted as much as possible by irreguralities in the capacities of the respective unit cells. SOLUTION: A terminal voltage of a combined battery 22, which is constituted by connecting three unit cells 21(1)-21(3) in series is divided with a voltage dividing circuit 26 constituted by connecting resistors 23, 24, 25 in series. On the basis of output signals of comparators 27H-28L, a logic circuit 37 turns on a switch 35 of a discharge circuit 33, corresponding to a unit cell whose terminal voltage, is higher than a mean voltage, from among the unit cells 21(1)-21(3), and makes the unit automatically discharge, so that irregularities are eliminated by making the terminal voltages of all the unit cells 21(1)-21(3) almost equal in the end.