Switched capacitor system for automatic battery equalization
First Claim
1. An apparatus for equalizing output voltages of at least two batteries comprising:
- a capacitive storage element;
first and second switching circuits coupled to said storage element;
a control circuit wherein said control circuit is coupled to said switching circuits and wherein said switching circuits, in response to said control circuit, couple said storage element to first one battery and then the other thereby equalizing output voltages thereof.
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Accused Products
Abstract
A switched capacitor system for automatic battery equalization can be used with series coupled batteries as well as primary and backup batteries which are alternately couplable to a load. The system includes a plurality of capacitors and a plurality of switching elements. Each of the capacitors is switched back and forth between a predetermined pair of batteries for the purpose of transferring charge therebetween and equalizing the output voltages of each of the batteries in the pair. The capacitors and switching elements can be configured in a modular fashion. Multiple modules can be used, for example, in combination with multiple batteries which are series coupled to one another. The system could be used in electric vehicles and in battery back-up systems of all types.
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Citations
38 Claims
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1. An apparatus for equalizing output voltages of at least two batteries comprising:
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a capacitive storage element; first and second switching circuits coupled to said storage element; a control circuit wherein said control circuit is coupled to said switching circuits and wherein said switching circuits, in response to said control circuit, couple said storage element to first one battery and then the other thereby equalizing output voltages thereof. - View Dependent Claims (2, 3, 4)
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5. A modular circuit for equalizing voltage on first and second batteries comprising:
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a passive electrical energy storage element; at least first and second solid state switches, wherein said switches each have a pole terminal and at least one output terminal and wherein said output terminals are coupled to respective batteries; and wherein said pole terminals of each of said switches are coupled to said storage element whereby electrical energy from one battery can be transferred to said storage element and then transferred to the other battery thereby equalizing voltages thereof. - View Dependent Claims (6, 7, 8, 9, 10)
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11. An electrical vehicle comprising:
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a moveable vehicle; a plurality of series connected, rechargeable storage cells; a plurality of battery equalization capacitors carried on said vehicle, wherein each of said capacitors is associated with at least one of said storage cells; and a plurality of solid state switches, coupled between said cells and said capacitors wherein first and second selected ones of said switches couple an associated capacitor to first one, then another of said cells to equalize output voltages thereof. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A vehicular propulsion system comprising:
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a platform supported by a plurality of wheels; an electric motor for driving at least one of said wheels to move said platform; a plurality of series coupled, rechargeable batteries; drive circuitry for coupling said plurality of batteries to said motor; and battery equalizer which includes; a plurality of battery balancing capacitors and a plurality of solid state switches wherein each said switch and an associated capacitor are coupled to a common node; and wherein said capacitors are switchable between first and second batteries from said plurality at a predetermined rate thereby to minimize voltage differences therebetween. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method of equalizing output voltages of first and second batteries comprising:
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(a) providing an electrical energy storage device; (b) coupling one of the batteries, having a higher output voltage than the other to the storage device and transferring electrical energy from the coupled battery to the storage device during a first time interval; (c) coupling the other of the batteries to the storage device and transferring at least part of the electrical energy stored thereat to the other battery during a second, different time interval; and (d) repeating steps (b)-(c) above. - View Dependent Claims (26, 27)
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28. An apparatus for equalizing output voltages of a plurality of batteries comprising:
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a capacitive storage element; switching circuits coupled to the batteries and to said element; and a control circuit coupled to said switching circuits and wherein said switching circuits in response to said control circuit couple said elements to said batteries sequentially thereby equalizing output voltages of the batteries. - View Dependent Claims (29)
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30. A system to supply DC-type electrical energy to a load primarily from a source of AC and secondarily from a plurality of batteries, the system comprising:
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at least first and second batteries; a battery equalizer having at least one battery voltage equalizing capacitor; at least first and second solid state switches wherein said switches couple said capacitor, first across one then the other of the batteries, at a predetermined rate, to thereby equalize output voltages thereof; a transfer switch having a primary input, a secondary import and output port wherein said secondary input is coupled to at least one of said batteries and said output port is coupled to the load; an AC to DC converter system with an AC input and a DC output wherein said AC input is couplable to a source of AC and said DC output is coupled to said primary input of said switch. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38)
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Specification