Abstract: According to one embodiment, a storage battery device includes a battery group, a charge-and-discharge control FET unit, and a drive controller. The battery group includes a plurality of battery cells connected in series. The charge-and-discharge control FET unit is connected to a low potential side of the battery group and includes at least a pair of N-channel MOSFETs source terminals of which are back-to-back connected. The drive controller outputs a drive control signal to a gate terminal of the respective N-channel MOSFETs included in the charge-and-discharge control FET unit. The drive control signal is generated based on a potential level of the source terminals.

Abstract: According to one embodiment, battery module includes a main circuit, a resistive element, a current-amount detection circuit, and a breaker. A charge and discharge current of a battery flows through the main circuit via a positive connecting terminal and a negative connecting terminal. The resistive element is provided in a current path branched from the main circuit, and able to form a closed circuit with an external control device via one of the positive connecting terminal and the negative connecting terminal while an insulating state between the main circuit and the external control device is maintained. The current-amount detection circuit detects an amount of current flowing through the resistive element, and outputs a current-amount detection signal. The breaker circuit interrupts the current flowing through the main circuit when the amount of current flowing through the resistive element is smaller than a predetermined threshold current based on the current-amount detection signal.

Abstract: An overcharge protection device according to an embodiment includes a switching unit and a controller. The switching unit includes a plurality of switching elements connected in series. The plurality of switching elements is connected in parallel to a fuse and a rechargeable battery. The fuse is interposed between and connected to the rechargeable battery and a charger configured to charge the rechargeable battery. The controller detects output voltage of the rechargeable battery, and, if the detected output voltage exceeds a certain overcharge detection voltage, short-circuits a positive electrode terminal and a negative electrode terminal of the rechargeable battery by turning on the switching elements.

Abstract: According to one embodiment, battery module includes a main circuit, a resistive element, a current-amount detection circuit, and a breaker. A charge and discharge current of a battery flows through the main circuit via a positive connecting terminal and a negative connecting terminal. The resistive element is provided in a current path branched from the main circuit, and able to form a closed circuit with an external control device via one of the positive connecting terminal and the negative connecting terminal while an insulating state between the main circuit and the external control device is maintained. The current-amount detection circuit detects an amount of current flowing through the resistive element, and outputs a current-amount detection signal. The breaker circuit interrupts the current flowing through the main circuit when the amount of current flowing through the resistive element is smaller than a predetermined threshold current based on the current-amount detection signal.