Method and device for monitoring battery cells of a battery pack and method and arrangement for balancing battery cell voltages during charge
First Claim
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1. A battery monitoring device of a battery pack configured for powering a cordless power tool, comprising:
- an integrated circuit connected to an microprocessor of the pack that is external to the integrated circuit, and connected to each of N battery cells of the pack, the integrated circuit configured to take, singly or sequentially, a sampled reading comprising one of an individual cell voltage or a total pack voltage for all cells in the pack, wherein the sampled reading is filtered in the integrated circuit prior to being read by the microprocessor.
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Abstract
A battery monitoring device of a battery pack configured for powering a cordless power tool may include an integrated circuit connected to a microprocessor of the pack that is external to the integrated circuit, and which is connected to each of N battery cells of the pack. The integrated circuit may be configured to take, singly or sequentially, a sampled reading comprising one of an individual cell voltage or a total pack voltage for all cells in the pack. The sampled reading is filtered in the integrated circuit prior to being read by the microprocessor.
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Citations
33 Claims
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1. A battery monitoring device of a battery pack configured for powering a cordless power tool, comprising:
an integrated circuit connected to an microprocessor of the pack that is external to the integrated circuit, and connected to each of N battery cells of the pack, the integrated circuit configured to take, singly or sequentially, a sampled reading comprising one of an individual cell voltage or a total pack voltage for all cells in the pack, wherein the sampled reading is filtered in the integrated circuit prior to being read by the microprocessor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of monitoring battery cells of a battery pack that is configured for powering a cordless power tool, comprising:
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receiving a first serial data command from a microprocessor of the pack to take a voltage measurement from channels connected to one or more of the cells, the voltage measurement embodied as a differential voltage value measured across an individual cell or a differential voltage value measured across all cells to reflect a total pack voltage, storing the voltage measurement in a capacitor, wherein the voltage measurement is filtered so that the capacitor charges up to an average of the differential voltage value for a given cell or across all cells of the pack, and receiving a second serial data command to connect the capacitor to a buffer amplifier so that the microprocessor can read the average voltage value off the capacitor.
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19. A method of balancing cell voltages while charging of a plurality of cells in a battery pack, comprising:
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periodically measuring the cell voltage across each cell of the pack and a total pack voltage in a sequential manner, determining, based on the measured total pack voltage, a current average cell voltage for all cells in the pack, the current average cell voltage representing a threshold value, comparing each measured cell voltage to the threshold value, and discharging one or more cells having a measured cell voltage which exceeds the threshold value for a given duration during the charge. - View Dependent Claims (20, 21, 22)
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23. An arrangement in a battery pack for balancing cell voltages during charging of a plurality of cells of the pack, the arrangement comprising:
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a microprocessor, and an integrated circuit in operative communication with the microprocessor and connected to each of the cells, the microprocessor directing the integrated circuit to periodically measure, throughout the duration of charging, the cell voltage across each cell of the pack and the total pack voltage in a sequential manner, the integrated circuit communicating the measured individual cell voltage and a current average cell voltage for all cells to the microprocessor, wherein the measured total pack voltage automatically divided by the number of cells within the integrated circuit to determine the current average cell voltage, and the microprocessor controlling balancing of each of the cell voltages based on each measured individual cell voltage and the determined current average cell voltage. - View Dependent Claims (24, 25, 26, 27)
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28. A method of adaptively balancing cell voltages of a plurality of cells in a battery pack during charging of the battery pack, comprising:
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continuously monitoring cell voltages for each cell in the pack in a sequential manner, detecting a voltage differential for one or more cells, the voltage differential represented as the difference a given measure cell voltage exceeds a current average cell voltage value calculated from the continuously monitoring step, and balancing cell voltages during the charge by discharging those cells which have a detected voltage differential, until a measured cell voltage for the discharging cell has dropped to equal the average cell voltage.
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29. A battery pack configured to monitor voltages of cells therein, the battery pack operatively attachable to a cordless power tool, comprising:
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a microprocessor;
an integrated circuit in operative communication with the microprocessor for monitoring cell voltages of at least N individual cells and total pack voltage during discharge of the pack, based on commands received from the microprocessor, and a motor control semiconductor device operatively controlled by the microprocessor, wherein as the battery pack is engaged to a cordless power tool, and upon an initial actuation of a trigger of the power tool, the microprocessor directs the integrated circuit to sequentially measure the individual cell voltages of all the cells, and wherein the microprocessor energizes the motor control semiconductor device to enable battery current to flow to a motor of the power tool, if the determined individual cell voltages are acceptable as compared to a given voltage threshold. - View Dependent Claims (30, 31, 32, 33)
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Specification