Patent ID: 7737658

Claim:
A battery pack having a secondary battery, the battery pack comprising: a voltage converter configured to provide a discharging voltage or a charging voltage based on an operational mode of the battery pack; a switching unit which switches the operation mode of the voltage converter between a charging mode in which the voltage converter is electrically coupled between the secondary battery and a power input terminal and a discharging mode in which the voltage converter is operatively electrically coupled between the secondary battery and a power output terminal; a power controlling unit configured to turn the voltage converter on or off; a voltage converter sensing unit configured to send a signal indicative of a temperature of the voltage converter to the power controlling unit; a secondary battery sensing unit coupled to the secondary battery and configured to send a signal indicative of the temperature of the secondary battery to the power controlling unit; a case housing the secondary battery, voltage converter, and the switching unit; and a plug having blades for reception into a power receptacle, the plug rotatably coupled to the case and having a first state when rotated to a first position and effecting the switching unit to switch the operation mode of the voltage converter to the charging mode and a second stated when rotated to a second position and effecting the switching unit to switch the operation mode of the voltage converter to the discharging mode, wherein, the power controlling unit is configured to turn off the voltage converter when the temperature of the voltage converter or secondary battery exceeds a predetermined threshold, in the charging mode, a charging voltage is output to the secondary battery, and in the discharging mode, a voltage of the secondary battery is converted into a predetermined discharging voltage and the converted voltage is output.