CELL VOLTAGE EQUALIZER FOR MULTI-CELL BATTERY PACK
First Claim
1. A cell voltage equalizer for a multi-cell battery pack which includes a plurality of cells connected together in series and outputs a desired voltage, the cell voltage equalizer configured to equalize output voltages from the respective cells, the cell voltage equalizer comprising:
- a voltage measuring device configured to measure the output voltages from the respective cells;
a discharge device, provided to each of the cells, configured to discharge the output voltages from the respective cells by causing electric currents to flow between positive electrodes and negative electrodes of the cells;
a state-of-charge measuring device configured to find a state of charge of the multi-cell battery pack on the basis of at least an output voltage from a cell out of the output voltages from the cells which are measured by the voltage measuring device, and judging whether or not the state of charge is a predetermined level not greater than a preset first threshold value;
a differential value arithmetic device configured to find differential values by subtracting a preset predetermined baseline voltage from the output voltages from the cells measured by the voltage measuring device; and
an equalization controlling device configured to equalize the output voltages from the respective cells if there exists a cell whose differential value found by the differential value arithmetic device is not less than a first voltage threshold value, by making the cell discharged by the discharge device which is provided to the cell, whereinin a case where the state of charge measured by the state-of-charge measuring device is not the predetermined level, the equalization controlling device performs the equalizing process on the cells on the condition that a preset first waiting time has passed since the previous equalizing process, andin a case where the state of charge is the predetermined level, the equalization controlling device performs the equalizing process on the cells on the condition that a second waiting time, which is shorter than the first waiting time, has passed since the previous equalizing process.
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Accused Products
Abstract
Cell voltage equalizer includes voltage detection ICs configured to measure output voltages from cells, respectively; discharge circuits (40) provided to the respective cells, and configured to discharge the output voltages from the respective cells; and a main microcomputer (33 configured: to find a state of charge of a rechargeable battery (13) on the basis of the output voltages from the cells measured by the voltage detection ICs; to judge whether or not the state of charge is a predetermined level; to find differential values by subtracting a predetermined baseline voltage from the output voltages from the cells measured by the voltage detection ICs; and to equalize the output voltages if there exists a cell whose differential value is not less than a first voltage threshold value, by use of the corresponding discharge circuit (40).
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Citations
4 Claims
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1. A cell voltage equalizer for a multi-cell battery pack which includes a plurality of cells connected together in series and outputs a desired voltage, the cell voltage equalizer configured to equalize output voltages from the respective cells, the cell voltage equalizer comprising:
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a voltage measuring device configured to measure the output voltages from the respective cells; a discharge device, provided to each of the cells, configured to discharge the output voltages from the respective cells by causing electric currents to flow between positive electrodes and negative electrodes of the cells; a state-of-charge measuring device configured to find a state of charge of the multi-cell battery pack on the basis of at least an output voltage from a cell out of the output voltages from the cells which are measured by the voltage measuring device, and judging whether or not the state of charge is a predetermined level not greater than a preset first threshold value; a differential value arithmetic device configured to find differential values by subtracting a preset predetermined baseline voltage from the output voltages from the cells measured by the voltage measuring device; and an equalization controlling device configured to equalize the output voltages from the respective cells if there exists a cell whose differential value found by the differential value arithmetic device is not less than a first voltage threshold value, by making the cell discharged by the discharge device which is provided to the cell, wherein in a case where the state of charge measured by the state-of-charge measuring device is not the predetermined level, the equalization controlling device performs the equalizing process on the cells on the condition that a preset first waiting time has passed since the previous equalizing process, and in a case where the state of charge is the predetermined level, the equalization controlling device performs the equalizing process on the cells on the condition that a second waiting time, which is shorter than the first waiting time, has passed since the previous equalizing process. - View Dependent Claims (2, 3, 4)
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Specification