Voltage balancer device for combination battery
First Claim
1. A voltage balancer device for a combination battery, the combination battery having a plurality of at least three of rechargeable cells connected in series, the voltage balancer device comprising:
- a potential divider circuit connected in parallel to the combination battery for detecting an average voltage of all of said cells;
a comparator for comparing the average voltage of all of said cells with an actual voltage of each of said cells; and
means for discharging the cells having a voltage higher than the average voltage to eliminate voltage unevenness among the cells.
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Accused Products
Abstract
A large number of rechargeable unit cells connected in series forming a combination battery are divided into groups of cells, each group including several cells, preferably, three to five cells. Voltage unevenness among the cells in each group is eliminated by operation of a voltage balancer device connected to each group of cells. The voltage balancer device includes a circuit for equally dividing a terminal voltage of the group of cells and obtaining an average voltage among the cells. The average voltage is compared with an individual cell voltage, and the cells having a voltage higher than the average voltage are discharged so that all cell voltages in the group become equal. A plurality of the battery modules each including the group of cells and the voltage balancer device are connected in series to form a single combination battery, and voltage unevenness among the battery modules are controlled by another voltage control device. The voltage unevenness among cells in a group may be eliminated by charging a capacitor from cells having a higher voltage and charging cells having a lower voltage from the charged capacitor. Thus, the voltage unevenness among the combination battery cells is eliminated by a simple and inexpensive device.
85 Citations
14 Claims
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1. A voltage balancer device for a combination battery, the combination battery having a plurality of at least three of rechargeable cells connected in series, the voltage balancer device comprising:
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a potential divider circuit connected in parallel to the combination battery for detecting an average voltage of all of said cells; a comparator for comparing the average voltage of all of said cells with an actual voltage of each of said cells; and means for discharging the cells having a voltage higher than the average voltage to eliminate voltage unevenness among the cells. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A combination battery system including a plurality of battery modules connected in series and means for eliminating voltage unevenness among the battery modules, at least one battery module comprising:
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a group of at least three rechargeable cells connected in series; a potential divider circuit connected in parallel to the group of rechargeable cells for detecting an average voltage of all of said cells; a comparator for comparing the average voltage of all of said cells with an actual voltage of each of said cells; and means for discharging the cells having a voltage higher than the average voltage to eliminate voltage unevenness among the cells in the group.
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11. A voltage balancer device for a combination battery, the combination battery having a plurality of at least three rechargeable cells connected in series at respective cell junctions, the voltage balancer device comprising:
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a potential divider circuit connected in parallel to the combination battery, the potential divider circuit having a plurality of resistances connected in series at respective divider junctions for equally dividing a whole potential of the combination battery according to the number of cells, each divider junction corresponding to each cell junction; a comparator for comparing a potential of a divider junction with a potential of the cell junction corresponding to that divider junction; and means for discharging the cells which are located at a higher potential side of the combination battery when the potential of the divider junction is higher than the potential of the cell junction corresponding to that divider junction, and for discharging the cells which are located at a lower potential side of the combination battery when the potential of the divider junction is lower than the potential of the cell junction corresponding to that divider junction.
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12. A method of eliminating voltage unevenness among a plurality of at least three rechargeable cells connected in series forming a combination battery, the method comprising steps of:
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detecting an average voltage of all of said cells; comparing the average voltage with a voltage of each cell; and discharging the cells having a higher voltage than the average voltage, so that the voltages of each of the cells become substantially equal to each other.
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13. A voltage balancer device for a combination battery, the combination battery having a plurality of number n rechargeable cells connected in series, n being at least 3 and each cell in said series being designated in order by a number from 1 through n, the voltage balancer device comprising:
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a potential devider circuit connected in parallel to the combination battery and detecting an average voltage of all of said cells, each potential divider circuit comprising n equal resistances connected in series, each resistance in said series being designated in order by a number from 1 through n; a comparator for comparing the average of all of said cells with an individual voltage of each of the cells; and a discharging circuit for discharging the cells having an individual voltage higher than the average voltage. - View Dependent Claims (14)
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Specification