Patent ID: 8274260
Filing Date: 2012-09-25
Classification: H01M,Y02E

Abstract:
1. A battery pack which is configured to be connected to an electricity-charging apparatus that charges the battery pack or a load apparatus that discharges the battery pack, comprising: a secondary battery having a battery plus terminal and a battery minus terminal; a battery pack plus terminal configured to connect to a plus terminal of a load apparatus and a plus terminal of an electricity-charging apparatus; a discharging minus terminal, through which a discharging current of the secondary battery flows, configured to directly connect a minus terminal of the load apparatus; a charging minus terminal, through which a charging current of the secondary battery flows, configured to connect a minus terminal of the electricity-charging apparatus, the charging minus terminal being provided independently of the discharging minus terminal; a voltage detecting means for detecting the voltage of the secondary battery; a current detecting means for detecting an electric current which flows in the secondary battery, said current detecting means being provided between the battery minus terminal and the charging minus terminal; a detection line for detecting if a current flows in the discharging minus terminal, said detection line being provided between the battery minus terminal and the discharging minus terminal; a state detecting means for detecting whether the secondary battery is in an electricity-charging state in which the electricity-charging apparatus and the battery pack are connected to each other or in an electricity-discharging state in which the load apparatus and the battery pack are connected to each other; a receiving means for receiving, from the load apparatus, a power notification signal for deciding whether the secondary battery is in a power-on state or a power-off state; a power deciding means for deciding that the secondary battery is in the power-on state when the receiving means has received the power notification signal, and that the secondary battery is in the power-off state when the receiving means has not received the power notification signal; and a residual-capacity calculating means for, in response to the state detecting means detecting that the secondary battery is in the electricity-charging state, calculating the residual capacity of the secondary battery by accumulating the electric current which is detected by the current detecting means, and in response to the state detecting means detecting that the secondary battery is in the electricity-discharging state, and the power deciding means deciding that the secondary battery is in the power-off state, calculating the residual capacity of the secondary battery based on the voltage which is detected by the voltage detecting means, the residual capacity being calculated by accumulating the electric current only when the secondary battery is in the electricity-charging state, and the residual capacity being calculated based on the voltage only when the secondary battery is in the electricity-discharging state and in the power-off state, wherein: the power notification signal transmitted from the load apparatus is indicative of a driving signal which flows in the load apparatus, said state detecting means decides that the secondary battery is in the electricity-charging state when the current detecting means detects the electric current, and that the secondary battery is in the electricity-discharging state when the detection line detects the current, the discharging minus terminal is configured to be directly connected to the battery minus terminal of the secondary battery, the charging current is smaller than the discharging current, and said current detecting means includes an electric current sensor configured to detect an electric current which flows in the secondary battery in the electricity-charging state.