BATTERY PACK FOR CORDLESS POWER TOOLS
First Claim
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1. An electronics module of a battery pack for powering a cordless power tool, the pack including a plurality of lithium-ion battery cells therein, the module comprising:
- an integrated circuit which includes a first voltage monitoring unit for monitoring individual lithium-ion cell voltages and total stack voltage of the lithium cells during charge and discharge operations;
a microcontroller external to and in connection with the integrated circuit;
a discharge FET for controlling one of current and power output from the battery pack to control a motor of the tool, wherein the microcontroller selectively controls the discharge FET so as to control current to the tool motor;
a second voltage monitoring circuit distinct from the first voltage monitoring unit that monitors individual cell voltages and, without interfacing with the battery electronic control unit, generates a disable signal in a charge operably coupled to the battery pack when any cell reaches an over-voltage condition during a charging operation; and
a fuse in a charge return line to the module.
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Abstract
A battery pack which includes a battery pack electronic control circuit adapted to control an attached power tool and/or an attached charger. The battery pack includes additional protection circuits, methodologies and devices to protect against fault conditions within the pack, as the pack is operatively attached to and providing power to the power tool, and/or as they pack is operatively attached to and being charged by the charger.
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Citations
18 Claims
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1. An electronics module of a battery pack for powering a cordless power tool, the pack including a plurality of lithium-ion battery cells therein, the module comprising:
an integrated circuit which includes a first voltage monitoring unit for monitoring individual lithium-ion cell voltages and total stack voltage of the lithium cells during charge and discharge operations; a microcontroller external to and in connection with the integrated circuit; a discharge FET for controlling one of current and power output from the battery pack to control a motor of the tool, wherein the microcontroller selectively controls the discharge FET so as to control current to the tool motor; a second voltage monitoring circuit distinct from the first voltage monitoring unit that monitors individual cell voltages and, without interfacing with the battery electronic control unit, generates a disable signal in a charge operably coupled to the battery pack when any cell reaches an over-voltage condition during a charging operation; and a fuse in a charge return line to the module. - View Dependent Claims (2, 3, 4, 5, 6, 12)
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7. A secondary circuit for providing over-voltage protection for battery cells in a battery pack, the battery pack having a first voltage monitoring circuit that monitors individual cell voltages of battery cells residing in the battery pack, the secondary circuit comprising:
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a secondary voltage monitoring circuit in the battery pack, distinct from the first voltage monitoring circuit, that monitors individual cell voltages and sends a disable signal to a battery charger operably coupled to the battery pack upon detecting any cell reaching an over-voltage condition; and a second circuit in the battery charger configured to receive the disable signal and interrupt charge current from the charger in response to the disable signal. - View Dependent Claims (8, 9, 10)
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11. A cordless power tool system having a battery pack that operably couples to a battery charger, the system includes a first voltage monitoring unit that monitors individual cell voltages of battery cells residing in the battery pack and a charge control unit that controls delivery of a charge current to the battery pack during charging, the battery pack comprising:
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a housing; a plurality of battery cells within the housing; and a secondary voltage monitoring circuit separate from the first monitoring unit that monitors the plurality of battery cells individually to detect when any cell reaches an over-voltage condition and provides a disable signal to the battery charger upon detecting a battery cell having an over-voltage condition, wherein the battery charger interrupts the charge current in response to receiving the disable signal. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification