Patent ID: 7830121
Filing Date: 2010-11-09
Classification: H02J

Abstract:
1. A battery pack comprising: a secondary battery; a measurement unit for measuring a terminal voltage and a current of the secondary battery; a protection unit for preventing the secondary battery from being overcharged when the terminal voltage measured by the measurement unit is equal to or higher than an overcharge detection voltage; and a control unit to which the terminal voltage and current measured by the measurement unit are input, the control unit having a first operating mode and a second operating mode in which the consumed current is small, as compared to that in the first operating mode, wherein: a voltage in a range of from a full charge voltage of the secondary battery to less than the overcharge detection voltage is defined as a voltage threshold, the control unit changes from the first operating mode to the second operating mode when a state in which a transition requirement is satisfied lasts for a predetermined period of time, and the transition requirement is that the current measured by the measurement unit be smaller than a current threshold and the terminal voltage measured be equal to or smaller than the voltage threshold.