Charging end time specifying method, charging end time specifying device, and battery pack

摘要

After the highest voltage of a rechargeable battery becomes higher than 4.0 V, when the charging current keeps lower than 50 mA for 20 seconds, a first point is detected for stopping charging the battery. Also, after the highest voltage becomes higher than 4.0 V, the charged capacity value and the discharged capacity value are added and subtracted for integrating the charged/discharged capacity if the highest voltage keeps higher than the integration start voltage. When the integration result shows that the battery is charged totally after the highest voltage becomes higher than 4.0 V, and when the absolute value of the integration result becomes larger than 50% of the designed capacity of the battery, the point second is detected for stopping charging the battery.