CHARGE CONTROLLER, BATTERY PACK, AND CHARGE CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To increase the estimation accuracy of the charging rate on a vehicle mounted with no auxiliary battery.SOLUTION: A battery ECU 201 electrically connected to a main battery 202 is provided irrespective of the state of a main switch 204 which is connected parallel to the main battery 202 across the main battery 202 mounted on a vehicle and a load 70. The battery ECU 201 turns the main switch 204 OFF to obtain an open circuit voltage of the main battery 202. The battery ECU 201 subsequently turns ON the main switch 204. The battery ECU 201 estimates the charging rate of the main battery 202 using the obtained open circuit voltage.