System and method for cell balancing and charging using a serially coupled inductor and capacitor
First Claim
1. A method for charging and balancing a plurality of series-coupled battery cells, comprising the steps of:
- receiving a charging voltage for the plurality of series-coupled battery cells;
transferring charge from a primary side of a transformer to a plurality of portions of a secondary side in a charging mode by generating a resonant input to the primary side of the transformer responsive to the charging voltage;
dividing the voltage from the primary side amongst the plurality of portions of the secondary side in proportion to an amount of charge needed by at least one battery cell associated with the portion of the secondary side;
coupling a total series voltage of the plurality of series-coupled battery cells to the primary side of the transformer in a discharging mode;
increasing an impedance between the portion of the secondary side and the at least one of the plurality of series-coupled battery cells in a first state; and
decreasing the impedance between the portion of the secondary side and the at least one of the plurality of series-coupled battery cells in a second state.
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Accused Products
Abstract
An apparatus for charging a plurality of series connected battery cells, includes a first and second input terminals for providing a charging voltage to the plurality of series connected battery cell. A transformer includes a primary side associated with the charging voltage and a secondary side includes a plurality of portions. Each of the plurality of portions is connected across at least one of the plurality of series connected battery cell. A switch in series between each of the plurality of portions of the secondary side and the at least one of the plurality of series connected battery cells increases an impedance between the portion of the secondary side and the associated one of the plurality of series connected battery cells in a first state and decreases the impedance between the portion of the secondary side and the associated one of the plurality of series connected battery cells in a second state.
25 Citations
15 Claims
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1. A method for charging and balancing a plurality of series-coupled battery cells, comprising the steps of:
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receiving a charging voltage for the plurality of series-coupled battery cells; transferring charge from a primary side of a transformer to a plurality of portions of a secondary side in a charging mode by generating a resonant input to the primary side of the transformer responsive to the charging voltage; dividing the voltage from the primary side amongst the plurality of portions of the secondary side in proportion to an amount of charge needed by at least one battery cell associated with the portion of the secondary side; coupling a total series voltage of the plurality of series-coupled battery cells to the primary side of the transformer in a discharging mode; increasing an impedance between the portion of the secondary side and the at least one of the plurality of series-coupled battery cells in a first state; and decreasing the impedance between the portion of the secondary side and the at least one of the plurality of series-coupled battery cells in a second state. - View Dependent Claims (2, 3)
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4. An apparatus, comprising:
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first and second nodes configured to be coupled across a first plurality of series-coupled battery cells; a series combination of an inductor and a capacitor, the series combination having a third node coupled to the second node and having a fourth node; a transformer having a first primary side coupled between the second node and the fourth node, and having a first secondary side including a plurality of portions each coupled across a respective at least one of the plurality of series-coupled battery cells, the transformer and the series combination of the inductor and the capacitor configured to resonate and balance a charge on at least one of the battery cells relative to a charge on at least one other of the battery cells; and a respective first electronic device in series between each of the plurality of portions of the secondary side and the respective at least one of the plurality of series-coupled battery cells, the respective electronic device configured to decrease an impedance between the portion of the secondary side and the at least one of the plurality of series-coupled battery cells while the transformer and the series combination of the inductor and the capacitor are balancing the charge on the at least one of the plurality of series-coupled battery cells. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. An apparatus for charging and balancing a first plurality of series-coupled battery cells, the apparatus comprising:
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first and second input terminals for providing a charging voltage to the first plurality of series-coupled battery cells; a transformer including a primary side associated with the charging voltage and a secondary side including a plurality of portions, each of the plurality of portions coupled across at least one of the first plurality of series-coupled battery cells; a series resonant circuit coupled between the primary side of the transformer and at least one of the first and second input terminals; a switch in series between each of the plurality of portions of the secondary side and the at least one of the first plurality of series-coupled battery cells for increasing an impedance between the portion of the secondary side and the at least one of the first plurality of series-coupled battery cells in a first state and for decreasing the impedance in a second state; wherein in a charging mode charge on the primary side is transferred to the plurality of portions of the secondary side the charge from the primary side divided amongst the plurality of portions of the secondary side in proportion to an amount of charge needed by the at least one battery cell associated with the portion of the secondary side, and in a discharging mode the primary side of the transformer is coupled to a total series voltage of the first plurality of series-coupled battery cells; wherein each of the at least one of the first plurality of series-coupled battery cells includes a respective second plurality of series-coupled battery cells; at least one pair of second and third input terminals each associated with one of the second plurality of series-coupled battery cells for providing a second charging voltage to the second plurality of series-coupled battery cells; at least one second transformer each associated with one of the second plurality of series-coupled battery cells including a second primary side associated with the second charging voltage and a second secondary side including a second plurality of portions, each of the second plurality of portions coupled across an associated battery cell of the second plurality of series-coupled battery cells; and at least one second switch each coupled in series between each of the second plurality of portions of the secondary side and the associated battery cell for increasing an impedance between the second portion of the secondary side and the battery cell in a first state and for decreasing the impedance between the second portion of the secondary side and the associated battery cell in the second state. - View Dependent Claims (12, 13, 14, 15)
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Specification