Abstract: In order to prevent a battery pack from being overly discharged during use in a power tool, a discharge voltage limit circuit is provided. The circuit disconnects the battery pack from the motor when the voltage of the battery pack falls below a predetermined level. However, the circuit is operable only when the main switch is OFF, that is, when no load is imposed on the motor.

Abstract: When a battery pack having an output voltage of 14.4 V that is connectable to an electric tool in a sliding manner is used as a power supply source for the electric tool that is connectable to a battery pack in an insertion manner and has a rated voltage of 12 V, the electric tool and the battery pack are connected to each other with an adaptor interposed therebetween. The adaptor has an FET that is switched at a predetermined duty of a predetermined frequency. The battery pack and the electric tool are connected or disconnected to or from each other by the switching operation, thereby dropping the output voltage of the battery pack. The voltage from the battery pack is detected. When the detected voltage is out of a predetermined value range, it is judged that the overcurrent or overdischarge has occurred. Then, the FET is turned off to stop the electric tool.

Abstract: A charging device has a charging unit and a control unit. The charging unit charges a battery pack the battery pack being either a first type or a second type of battery pack. The first type of battery pack includes a single battery cell or a first plurality of battery cells connected in series. The second type of battery pack includes a single battery unit or a second plurality of battery units connected in series. Each battery unit includes at least two battery cells connected in parallel. The control unit controls the charging unit to control at least one of a charging current flowing through the battery pack and a charging voltage applied across the battery pack, depending on the battery pack to be charged.

Abstract: A setting current switching circuit 120 includes a comparator 127. A battery temperature signal corresponding to a battery temperature detected by a battery temperature detecting unit 8 is inputted to one input terminal (?) of the comparator 127 and a reference signal corresponding to a reference temperature is inputted to the other input terminal (+) of the comparator 127 to vary the setting charging current value of a charging current setting unit 80 and the setting full-charge current value of a full-charge current setting unit 90 correspondingly to the output of the comparator 127.

Abstract: A cordless power tool uses a lithium battery as a power source of a motor and is provided with an overcurrent protection circuit. The circuit allows an overcurrent to instantaneously flow at the start-up time of the motor and shuts off an overcurrent which may flow when the motor is brought into a locked state during the use of the power tool.

Abstract: A battery device is constituting by connecting such cell assemblies in parallel as each comprises: a first cell group having a plurality of cells connected in series; a housing container for housing said first cell group; current detecting means housed in said container for detecting a current to flow through the first cell group; a switching element connected with said first cell group for turning ON/OFF the current to flow through said first cell group; and means for controlling the ON/OFF of said switching element in response to the output signal of said current detecting means.

Abstract: A charging signal Vi responding to a charging current is inputted to one input terminal (?) of an operational amplifier 95 forming a comparator and a setting signal Vr corresponding to a setting current value is inputted to the other input terminal (+) of the operational amplifier 95. When the charging signal Vi is not higher than the setting signal Vr, a charging stop signal is generated from the output terminal of the operational amplifier 95 to interrupt a switch unit 4. A starting signal Vcc larger than the setting signal Vr applied to the other input terminal (+) is applied to the one input terminal (?) of the operational amplifier 95 through a condenser 94 till a prescribed time elapses from the start of a charging operation to generate a charging start signal from the output terminal of the operational amplifier 95 and electrically conduct the switch unit 4.

Abstract: A battery charger for charging a lithium-ion battery includes a temperature control unit and a current supplying unit. The temperature control unit controls a temperature of the lithium-ion battery to fall in a predetermined range. The predetermined range is divided into a plurality of sub-divided temperature ranges. The current supplying unit supplies the lithium-ion battery with a temperature-dependent current relation to a sub-divided temperature range in which the temperature of the lithium-ion battery falls.

Abstract: To reduce power consumption when charging a secondary battery is not performed, a first power supply circuit is disabled but a second power supply circuit is enabled when the secondary battery is unloaded from a battery charger. Both the first and second power supply circuits are enabled when the battery is loaded in the charger. The first power supply circuit is provided for supplying power to the secondary battery. The second power supply circuit is provided for supplying a first voltage to such components that are operated with the first voltage and a second voltage to such components that are operated with the second voltage, wherein the second voltage is greater than the first voltage. When the battery is unloaded from the charger, the second power supply circuit supplies only the first voltage whereas when the battery is loaded in the charger, the second power supply circuit supplies the first and second voltages to the corresponding components.

Abstract: A battery pack includes a plurality of lithium battery cells, an analog thermo sensing member, and an analog switch. The analog thermo sensing member detects, in an analog form, a battery temperature of at least one of the plurality of lithium battery cells, and outputs an output preventing signal if the battery temperature is over a first predetermined temperature. The analog switch element is the plurality of lithium battery cells in series, and is switched, based on the output preventing signal, to a state in which a current is prevented from flowing in the plurality of lithium battery cells.

Abstract: To prevent a battery pack from being over-discharged even under a state that the battery pack (a secondary battery) is connected to a discharging device that is not connected to an ac input power source for a long time. A charging device 200 has a pair of output lines L1 and L2 and an anode terminal O1 and a cathode terminal O2 of a secondary battery 2 electrically connected between the output lines L1 and L2 to carry out a charging operation. In the charging device 200 including a component circuit part (a resistance 33, a series connecting circuit of resistances 102, 103 and 105, a series connecting circuit of resistances 91 and 92 and an inner circuit part of a shunt regulator 116) electrically connected by traversing a part between the pair of output lines L1 and L2, a switching element 121 is inserted between the component circuit part (the resistance 33 or the like) and one of the pair of output lines L1 and L2.

Abstract: To provide a universal battery charger with low power consumption during a standby condition and a rush current suppressing capability at the time of commencement of charging, a voltage slightly larger than a battery voltage is produced and applied to the battery. Thereafter, the highest voltage is produced and applied to the battery to charge the same. When the battery is unloaded from the battery charger, the lowest voltage is produced to save power consumption.

Abstract: A power tool 1 is connected to a battery pack 5 including an overcurrent detector 533 which detects overcurrent of a battery module 51 and outputs a detection signal, and an overdischarge detector 532 which detects overdischarge of the battery module 51 and outputs a detection signal. The power tool 1 includes a motor 2 which is driven by electric power supplied from the battery pack 5, a trigger switch 31 for setting the power supply from the battery pack 5 to the motor 2 in ON/OFF state, and an FET 410 which sets the power supply to the motor 2 in ON/OFF state on the basis of the detection signal from the overcurrent detector 533 or the overdischarge detector 532.

Abstract: A power tool includes a main housing, a motor, a hammer case, an end-tool holding part, a driving-force transmitting mechanism, a light-unit mounting part, a light unit, and a cover. The motor is accommodated in the main housing and is configured to generate a driving force. The hammer case has an outer peripheral surface. The end-tool holding part is configured to hold an end tool. The driving-force transmitting mechanism is accommodated in the hammer case. The driving-force transmitting mechanism is configured to transmit the driving force to the end-tool holding part. The light-unit mounting part is formed integrally with the hammer case. The light unit is mounted to the light-unit mounting part. The cover covers the outer peripheral surface of the hammer case and accommodates the light-unit mounting part and the light unit.

Abstract: In a battery pack which comprises: a battery set 2 composed of two or more lithium battery cells 21 connected in series; a first protection circuit 32 including a first voltage detect part 321 for detecting the voltage(s) of a part of the two or more battery cells, and a first signal output part 325 for issuing an output signal when a detect voltage detected by the first voltage detect part 321 goes below a given over-discharge judgment voltage value; a second protection circuit 33 including a second voltage detect part 331 for detecting the voltage(s) of another part of the two or more battery cells, and a second signal output part 335 for issuing an output signal when the detect voltage of the battery cell 21 detected by the second voltage detect part 331 goes below a given over-discharge judgment voltage value; and, a switch 31 which is connected to the current path of the battery set 2 and can be turned on or off according to the output signals of the first and second signal output parts 325 and 335, ther

Abstract: In a charging device, a driving power supply circuit for driving a control circuit is formed as a separate system from a first power supply circuit, regardless of whether the first power supply circuit is in a driving state or a non-driving state. A microcomputer alternately and intermittently controls the first power supply circuit in the driving state or the non-driving state when the battery pack is not mounted in the charging device in order to reduce the potential difference between the battery pack and the output voltage of the first power supply circuit, thereby avoiding an excessive discharge current from the battery pack when the battery pack is mounted in the charging device.

Abstract: A charging device includes a battery voltage detecting circuit for detecting the voltage of a battery pack; and a microcomputer having RAM for temporarily storing a battery voltage detected by the battery voltage detecting circuit, and a CPU for calculating a battery voltage gradient from the battery voltage detected by the battery voltage detecting circuit and a battery voltage sampled a prescribed time earlier. The charging device determines that the life of the battery has expired when the voltage of the battery pack prior to charging is less than or equal to a prescribed value J and the battery voltage gradient within a prescribed time period after the start of charging is greater than or equal to a first prescribed value K. The charging device also includes a display circuit for notifying the user when the life of the battery pack has deteriorated.

Abstract: A DC power source unit supplies a DC voltage to a power tool through an adapter when a power switch of the tool is turned ON and also charges a battery pack used as an alternative power source of the tool when the power tool is not operated. A minimum battery temperature gradient amongst battery temperature gradients ever computed is used to determine whether the battery pack has cooling effect when forcibly cooled by a cooling fan or whether the battery pack has reached a full charge condition. When charging the battery pack is interrupted due to operation of the power tool, computing the battery temperature gradient is halted for some time or determination of the battery pack's full charge condition is not performed for some time in order to prevent the minimum battery temperature from being updated during interruption of charging of the battery pack.

Abstract: A battery charger for charging a lithium-ion battery includes a temperature control unit and a current supplying unit. The temperature control unit controls a temperature of the lithium-ion battery to fall in a predetermined range. The predetermined range is divided into a plurality of sub-divided temperature ranges. The current supplying unit supplies the lithium-ion battery with a temperature-dependent current relation to a sub-divided temperature range in which the temperature of the lithium-ion battery falls.

Abstract: A compact battery pack with high handling ability and restraining degradation of battery cells. The battery pack includes an insertion portion to be inserted into a handle portion of a cordless power tool and an accommodation portion in which all battery cells are accommodatable. A protection board with a protection circuit that protects batteries against overcharge and over-discharge is installed in the insertion portion. A switching element is connected between the battery cells and a drive motor of the power tool. An air passage in communication with the battery pack is formed within the handle and a main housing of the cordless power tool. The switching element is positioned at the air passage.