Abstract: A cordless power tool has a housing which includes a mechanism to couple with a removable battery pack. The battery pack includes one or more battery cells as well as a vent system in the battery pack housing which enables fluid to move through the housing. A mechanism is associated with the battery pack to dissipate heat from the battery pack.

Abstract: A system of cordless power tools includes a cordless power tool adapted to removably receive a rechargeable battery pack. The system further includes a battery pack charger and a converter for converting AC electricity to DC electricity. A battery pack interface block is captured between clam shell halves of a battery pack housing and includes a plurality of male blade terminals. The male blade terminals are received within recessed female terminals of a tool terminal block and similarly received by recessed female terminals of the charger. The tool terminal block further includes a pair of male terminals which engage recessed female terminals of the converter.

Abstract: A method for charging a rechargeable battery pack includes identifying battery capacity, determining sampling interval length according to the battery capacity, and implementing the determined sampling interval length. Also disclosed herein is a method for charging batteries comprising identifying battery capacity, determining current-on period length in duty cycle according to the battery capacity, and implementing the determined current-on period length. Further, disclosed herein is a battery charging apparatus comprising a charger for charging first and second batteries, where the first battery comprises a microprocessor. The charger further comprises at least one terminal for receiving a battery identification signal, so that the charger can distinguish between the first and second batteries.

Abstract: A cordless power tool has a housing which includes a mechanism to couple with a removable battery pack. The battery pack includes one or more battery cells as well as a vent system in the battery pack housing which enables fluid to move through the housing. A mechanism is associated with the battery pack to dissipate heat from the battery pack.

Abstract: A method for charging a rechargeable battery pack includes identifying battery capacity, determining sampling interval length according to the battery capacity, and implementing the determined sampling interval length. Also disclosed herein is a method for charging batteries comprising identifying battery capacity, determining current-on period length in duty cycle according to the battery capacity, and implementing the determined current-on period length. Further, disclosed herein is a battery charging apparatus comprising a charger for charging first and second batteries, where the first battery comprises a microprocessor. The charger further comprises at least one terminal for receiving a battery identification signal, so that the charger can distinguish between the first and second batteries.

Abstract: A method for charging a rechargeable battery pack includes identifying battery capacity, determining sampling interval length according to the battery capacity, and implementing the determined sampling interval length. Also disclosed herein is a method for charging batteries comprising identifying battery capacity, determining current-on period length in duty cycle according to the battery capacity, and implementing the determined current-on period length. Further, disclosed herein is a battery charging apparatus comprising a charger for charging first and second batteries, where the first battery comprises a microprocessor. The charger further comprises at least one terminal for receiving a battery identification signal, so that the charger can distinguish between the first and second batteries.

Abstract: A system of cordless power tools includes a cordless power tool adapted to removably receive a rechargeable battery pack. The system further includes a battery pack charger and a converter for converting AC electricity to DC electricity. A battery pack interface block is captured between clam shell halves of a battery pack housing and includes a plurality of male blade terminals. The male blade terminals are received within recessed female terminals of a tool terminal block and similarly received by recessed female terminals of the charger. The tool terminal block further includes a pair of male terminals which engage recessed female terminals of the converter.

Abstract: A system of cordless power tools includes a cordless power tool adapted to removably receive a rechargeable battery pack. The system further includes a battery pack charger and a converter for converting AC electricity to DC electricity. A battery pack interface block is captured between clam shell halves of a battery pack housing and includes a plurality of male blade terminals. The male blade terminals are received within recessed female terminals of a tool terminal block and similarly received by recessed female terminals of the charger. The tool terminal block further includes a pair of male terminals which engage recessed female terminals of the converter.

Abstract: A system of cordless power tools includes a cordless power tool adapted to removably receive a rechargeable battery pack. The system further includes a battery pack charger and a converter for converting AC electricity to DC electricity. A battery pack interface block is captured between clam shell halves of a battery pack housing and includes a plurality of male blade terminals. The male blade terminals are received within recessed female terminals of a tool terminal block and similarly received by recessed female terminals of the charger. The tool terminal block further includes a pair of male terminals which engage recessed female terminals of the converter.

Abstract: A method for charging a rechargeable battery pack includes identifying battery capacity, determining sampling interval length according to the battery capacity, and implementing the determined sampling interval length. Also disclosed herein is a method for charging batteries comprising identifying battery capacity, determining current-on period length in duty cycle according to the battery capacity, and implementing the determined current-on period length. Further, disclosed herein is a battery charging apparatus comprising a charger for charging first and second batteries, where the first battery comprises a microprocessor. The charger further comprises at least one terminal for receiving a battery identification signal, so that the charger can distinguish between the first and second batteries.

Abstract: The charging method includes providing a current to the battery pack, sensing battery temperature, determining temperature change rate, and disabling termination of the charging method based on a temperature-based scheme if the temperature change rate exceeds a first predetermined threshold within a first predetermined period of time. Termination of the charging method based on a temperature-based scheme may be re-enabled if the temperature change rate is less than a second predetermined threshold. Preferably the second predetermined threshold is equal to the first predetermined threshold. Alternatively, termination of the charging method based on a temperature-based scheme may be re-enabled after a second predetermined period of time has elapsed.

Abstract: A method for charging and monitoring a rechargeable battery is proposed. The charging method includes charging a rechargeable battery, sensing temperature of said battery, and calculating temperature change rate. The method further includes sensing voltage of said battery after the temperature change rate reaches a predetermined value, calculating voltage change rate, and reducing current sent to the battery when the voltage change rate reaches a predetermined value. A second embodiment of the charging method may include charging a rechargeable battery, sensing temperature and voltage of said battery, and calculating temperature and voltage change rates. The method further includes sensing for a maximum voltage change rate after the temperature change rate reaches a predetermined value, and reducing current sent to the battery when the maximum voltage change rate is sensed.

Abstract: A battery charger including a battery temperature monitoring device. The battery temperature monitoring device includes a first thermistor bonded to one of the terminals of the battery charger to provide a temperature signal of the temperature of the terminal, and a second thermistor positioned within the battery charger to provide a temperature signal of the ambient temperature. The temperature signals from both the first and second thermistors are applied to a temperature monitoring circuit that compares the temperature signals to a known discharge rate of an RC circuit. A microprocessor receives output signals from the temperature monitoring circuit and, using an algorithm, determines the actual temperature of the battery.

Abstract: A method for charging and monitoring a rechargeable battery is proposed. The charging method includes charging a rechargeable battery, sensing temperature of said battery, and calculating temperature change rate. The method further includes sensing voltage of said battery after the temperature change rate reaches a predetermined value, calculating voltage change rate, and reducing current sent to the battery when the voltage change rate reaches a predetermined value. A second embodiment of the charging method may include charging a rechargeable battery, sensing temperature and voltage of said battery, and calculating temperature and voltage change rates. The method further includes sensing for a maximum voltage change rate after the temperature change rate reaches a predetermined value, and reducing current sent to the battery when the maximum voltage change rate is sensed.

Abstract: A battery monitor system that determines battery pack temperature and battery pack identification. The battery pack includes a battery pack circuit having a thermistor and an AC circuit component. The battery monitoring system determines the battery pack temperature by measuring the resistance of the thermistor when the battery pack circuit is in a steady-state condition, and determines the value of the AC component based on a changing or dynamic electrical condition of the battery pack circuit. In one embodiment, to determine battery pack identification, an identification capacitor is connected in circuit with the thermistor. One terminal of a comparator is switched to a low reference voltage potential once the identification capacitor has been charged, and the output of the comparator gives an indication of the discharge rate of the capacitor, and thus its identification.

Abstract: A battery charger including a battery temperature monitoring device. The battery temperature monitoring device includes a first thermistor bonded to one of the terminals of the battery charger to provide a temperature signal of the temperature of the terminal, and a second thermistor positioned within the battery charger to provide a temperature signal of the ambient temperature. The temperature signals from both the first and second thermistors are applied to a temperature monitoring circuit that compares the temperature signals to a known discharge rate of an RC circuit. A microprocessor receives output signals from the temperature monitoring circuit and, using an algorithm, determines the actual temperature of the battery.

Abstract: A battery charger for simultaneously charging a plurality of batteries from a single power source includes a microcontroller-based circuit that is programmed to multiplex full charging current sequentially to each battery in the charger. Charge termination in the preferred embodiment is determined by monitoring total charge time and by detecting a predetermined drop in battery voltage--i.e., "minus .DELTA.V". The microcontroller is programmed to individually track the actual charge time of each battery in the charger and to adjust the clock rate of each battery accordingly when multiple batteries are charged at the same time. In addition, the minus .DELTA.V charge termination criteria is temporarily disabled for any battery in the charging process when one or more batteries are inserted into the charger to prevent erroneous detection of a full charge condition.

Abstract: A state of charge test is first performed on the battery by applying a current pulse and then observing the voltage decay characteristics which result. Batteries which are initially nearly fully charged exhibit a larger voltage decay than batteries which are not as fully charged. The result of this initial state of charge test is used to determine how to best terminate battery charging. In this way battery overcharging is prevented regardless of the initial state of charge of the battery.

Abstract: The falling voltage slope charge termination routine is performed during intervals of the charging cycle in which signal-to-noise ratio is comparatively high. The falling voltage slope charge termination technique is automatically disabled or rendered less sensitive to noise during times when the signal-to-noise ratio is comparatively low. In this way, accurate charge termination is accomplished without error otherwise induced by voltage noise during charging. The charge termination technique responds quickly to a charged battery indication, since signal averaging to negate the effects of noise can be minimized or eliminated.

Abstract: An ultra-quick charging device for charging battery packs for an assortment of different appliances, such as power tools, having a wide range of output voltages. The charging device includes an AC to DC high current power supply circuit and a microcomputer-based controller circuit for monitoring the voltage of the battery and converting from fast charge to trickle charge when the second inflection point in the battery voltage charge curve is detected. In order to permit the device to charge battery packs of different rated voltages, the device includes a logarithmic analog-to-digital converter circuit having a selectable prescaler circuit that attenuates the battery voltage signal.