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 charging device includes a charging unit, a detecting unit, a determining unit, a current generating unit, an adjusting unit, and a display unit. The charging unit charges a battery. The detecting unit detects a voltage developed across the battery. The determining unit determines a charging state of the battery based on the voltage. The current generating unit generates a current. The adjusting unit adjusts the current based on the charging state. The display unit emits a first light having a first color and a first intensity in response to the current supplied thereto. The first intensity changes in accordance with changing of the current.

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: 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 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. In order to prevent a rush current from flowing in a switch interposed between a switching power source circuit and the battery pack when charging the battery pack is commenced, the switch is rendered OFF when the output voltage from the switching power source is greater than the battery voltage. Charging the battery is started upon once lowering the output of the switching power source to a level lower than the battery voltage.

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 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.

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 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 charger including a charging power supply circuit connected to an input power supply and adapted to charge a battery to be charged, a charging control circuit adapted to control charging of the battery, and a constant voltage power supply adapted to drive the charging control circuit, wherein the charging control circuit stops an output of the constant voltage power supply when the battery is detached from the charger.

Abstract: A battery charger detects a battery voltage, a battery temperature, and computes a change in the battery voltage between two timings at which the battery voltages are detected and also a change in the battery temperature between two timings at which the battery temperatures are detected. A charge current is determined based on the battery voltage gradient information, the battery temperature gradient information, and at least one of the battery voltage information and the battery temperature information. Also, a full charge discrimination value is also determined based on at least three parameters mentioned above. The battery is determined to be a full charge condition when the computed battery temperature change has exceeded a sum of the minimum battery temperature gradient value and the full charge discrimination value.

Abstract: A battery charger for charging a battery pack having a battery, a temperature sensor for sensing a temperature of the battery, and a battery terminal. The battery charger includes a charger terminal to which the battery terminal is connected when the battery is charged, a charge current generating circuit that generates a charge current for charging the battery, a battery temperature detector, and a controller. The battery temperature detector is configured to include a circuit, for example, to detect a temperature of the battery while cooperating with the temperature sensor and to output a temperature signal indicative of the temperature of the battery. The controller which is supplied with the temperature signal from the battery temperature detector, corrects the temperature signal, and provides a corrected temperature signal.

Abstract: A battery charging apparatus includes a switching power source supplying a current to a battery pack, an input voltage detecting unit detecting an input voltage of the switching power source, a charging current control unit that detects a charging current of the battery and controlling the charging current in accordance with a charging current set value, and a microcomputer detecting whether the current supplied to the battery to be charged is less than a predetermined value on the basis of a detection signal of the input voltage detecting unit and controls the charging current set value in accordance with the input voltage. When it is discriminated that the input voltage is less than a predetermined value on the basis of the detection signal, the microcomputer sets the charging current set value to be a value less than the predetermined value.

Abstract: A battery charger includes a battery voltage detector for detecting the voltage of a secondary battery and a battery temperature sensor for detecting the temperature of the secondary battery. A controller determines the voltage of the secondary battery prior to beginning the charging process based on output from the battery voltage detector. The controller also determines the charging level from among a plurality of levels that indicate how much time is required for the secondary battery to reach a full charge, based on the determined voltage of the secondary battery and output from the battery temperature sensor. A display is provided for displaying the charging level that indicates the time remaining to achieve a full charge.

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 charging apparatus includes a cooling fan; a battery temperature detecting unit; and a control unit configured to determine presence or non-presence of cooling effect by the cooling fan, and to control a charging current based on an output of the battery temperature detecting unit. When there is no cooling effect and the battery temperature reaches a first predetermined value smaller than a maximum value of a temperature range in which a battery is chargeable without making a life time thereof shorter, the control unit changes the charging current to a first charging current value where increase of the battery temperature can be suppressed. When there is cooling effect and the battery temperature reaches a second predetermined value higher than the first predetermined value, the control unit changes the charging current to a second charging current value larger than the first charging current value.

Abstract: A full charge condition of a battery is determined based on a battery temperature gradient computed at every sampling time based on two values of detected battery temperatures. However, the battery temperature detected when the level of a charge current is switched does not exhibit an accurate temperature of the battery due to contact resistance existing in contact portion of a battery side terminal and a charger side terminal, resulting in inaccurate detection of the full charge condition. A microcomputer corrects the battery temperatures detected after the level of the charge current is switched and the full charge determination is made through computation of the battery temperature gradient using the corrected battery temperatures.