Patent ID: 8148939

Claim:
A battery pack comprising a secondary battery, a positive charge and discharge terminal and a negative charge and discharge terminal which are connected to a positive electrode and a negative electrode of the secondary battery, respectively, and battery operating state detection means for detecting an operating state of the secondary battery, wherein: the battery operating state detection means includes at least one of a temperature detection means for detecting battery temperatures, a voltage detection means for detecting a battery voltage, and a current detection means for detecting a charging and discharging current, the battery pack is provided with information signal sending means which modulates operating state detection information detected by the battery operating state detection means into an operating state detection signal, which can be transmitted to a charging device for supplying charging energy to the secondary battery by connecting it to the positive charge and discharge terminal and the negative charge and discharge terminal or a loading device which is operated by the discharging energy of the secondary battery by connecting it to the positive charge and discharge terminal and the negative charge and discharge terminal through the positive charge and discharge terminal or the negative charge and discharge terminal, and sends the operating state detection signal thereto.