Abstract: A charge control device includes a voltage detector that detects a voltage of a battery, a temperature detector that detects a battery temperature, a voltage setting unit that sets at least one of a charge completion voltage and an abnormality determination voltage to a high temperature time voltage that is lower than a normal voltage when the battery temperature detected by the temperature detector is or is above a high temperature determination threshold set in advance, and a charging current limiting unit that reduces a charging current a charger supplies to the battery when the battery temperature is in a temperature range between a set temperature that is lower by a predetermined temperature than the high temperature determination threshold and the high temperature determination threshold and the battery voltage detected by the voltage detector is in a voltage range between the normal voltage and the high temperature time voltage.

Abstract: A battery pack includes: a connecting portion connected to a battery charger; a battery chargeable by the battery charger connected to the connecting portion; an environment temperature detecting element detecting an environment temperature around the battery; and a control circuit. The control circuit periodically detects the environment temperature via the environment temperature detecting element and controls the battery charger to suspend starting of charging the battery or to temporarily discontinue charging the battery when a variation of the environment temperature detected exceeds a predetermined range, when the battery charger is connected to the connecting portion.

Abstract: A battery pack for an electric power tool includes a control device that determines the necessity of a balancing control to reduce difference in voltages of cells of a battery based upon voltages of the respective cells measured by a voltage measuring device. The control device controls a subject cell, which is subject to the balancing control to discharge via the discharging device when the balancing control is determined to be necessary. A voltage measuring device measures the voltages of the respective cells when a battery charger detecting device detects the connection of the battery charger in a state where the battery has not been connected to the battery charger for a predetermined specified period of time or more and power feeding to the electric power tool has not been performed for the specified period of time or more.

Abstract: A charge control device includes a voltage detector that detects a voltage of a battery, a temperature detector that detects a battery temperature, a voltage setting unit that sets at least one of a charge completion voltage and an abnormality determination voltage to a high temperature time voltage that is lower than a normal voltage when the battery temperature detected by the temperature detector is or is above a high temperature determination threshold set in advance, and a charging current limiting unit that reduces a charging current a charger supplies to the battery when the battery temperature is in a temperature range between a set temperature that is lower by a predetermined temperature than the high temperature determination threshold and the high temperature determination threshold and the battery voltage detected by the voltage detector is in a voltage range between the normal voltage and the high temperature time voltage.

Abstract: A battery pack includes: a connecting portion connected to a battery charger; a battery chargeable by the battery charger connected to the connecting portion; an environment temperature detecting element detecting an environment temperature around the battery; and a control circuit. The control circuit periodically detects the environment temperature via the environment temperature detecting element and controls the battery charger to suspend starting of charging the battery or to temporarily discontinue charging the battery when a variation of the environment temperature detected exceeds a predetermined range, when the battery charger is connected to the connecting portion.

Abstract: A battery pack for an electric power tool includes a control device that determines the necessity of a balancing control to reduce difference in voltages of cells of a battery based upon voltages of the respective cells measured by a voltage measuring device. The control device controls a subject cell, which is subject to the balancing control to discharge via the discharging device when the balancing control is determined to be necessary. A voltage measuring device measures the voltages of the respective cells when a battery charger detecting device detects the connection of the battery charger in a state where the battery has not been connected to the battery charger for a predetermined specified period of time or more and power feeding to the electric power tool has not been performed for the specified period of time or more.