LITHIUM ION SECONDARY BATTERY CHARGING SYSTEM AND CHARGER

摘要

PROBLEM TO BE SOLVED: To efficiently and safely charge by suppressing a deterioration of a battery performance to a minimum limit, by controlling to charge according to a voltage of a battery cell in a battery pack containing a protective circuit. SOLUTION: A lithium ion secondary battery charging system comprises a cell voltage detector constituted as a differential amplifier of an amplification factor of '1' by an operational amplifier 13, and a charge controller 4 for monitoring a battery cell voltage and a charging current to control the charging voltage and the charging current. The controller 4 controls to charge by the voltage of the cell 1 without influence of a voltage drop of the circuit 2 in a battery pack P.