BALANCING DEVICE AND METHOD

• US 20150236534A1
• Filed: 02/17/2015
• Published: 08/20/2015
• Est. Priority Date: 02/18/2014
• Status: Active Grant

• Current Assignee: Silicon Works Co., Ltd.
• Original Assignee: Silicon Works Co., Ltd.
• Inventors: KIM, Jae Wan, SONG, Myoung Soo, YUN, Jin Kook
• Granted Patent: US 9,722,437 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits

Abstract

Provided are balancing device and method which can achieve a balancing function between energy storage units connected in series using a small number of switch elements, thereby reducing the manufacturing cost and size and enabling various balancing modes. The balancing device for balancing between a plurality of energy storage units a battery module, in which the energy storage units are connected in series, includes: a transformer; and a switch network comparing a cell switch unit, a polarity switch unit, and au auxiliary switch unit, wherein the auxiliary switch unit includes: a first auxiliary switch unit for connecting a second common node to one terminal of the secondary winding of the transformer; and a second auxiliary switch unit for connecting a first common node to the other terminal of the secondary winding of the transformer.

Claims

1. A balancing device for balancing for an energy storage module comprising a plurality of energy storage units connected in series between a first connection terminal and a second connection terminal, the device comprising:

a transformer comprising a primary and secondary windings; and

a switch network for dividing nodes between the first connection terminal, the plurality of energy storage units, and the second connection terminal into a first group and a second group, forming a first common node corresponding to nodes of the first group, forming a second common node corresponding to nodes of the second group, selectively connecting each of both terminals of the primary winding of the transformer to the first common node or the second common node, and connecting one of both terminals of the secondary winding of the transformer to the first common node and connecting another of both terminals of the secondary winding to the second common node, respectively.

2. The balancing device according to claim 1, wherein the switch network comprises:

a plurality of cell switch units configured to have each one terminal individually connected corresponding to the nodes of the first and second groups, and to have each another terminal individually connected in common corresponding to the first group and the second group, thereby forming the first common node and the second common node;

a polarity switch unit configured to comprise a plurality of polarity switches which are configured to selectively connect each of both terminals of the primary winding of the transformer to the first common node or the second common node; and

an auxiliary switch unit configured to comprise first and second auxiliary switches which are configured to connect one of both terminals of the secondary winding of the transformer to the first common node and connect another of both terminals of the secondary winding to the second common node, respectively.

3. The balancing device according to claim 2, wherein the polarity switch unit comprises:

a first polarity switch provided between one terminal of the primary winding of the transformer and the second common node;

a second polarity switch provided between the one terminal of the primary winding of the transformer and the first common node;

a third polarity switch provided between another terminal of the primary winding of the transformer and the second common node; and

a fourth polarity switch provided between the other terminal of the primary winding of the transformer and the first common node.

4. The balancing device according to claim 2, further comprising a module switch unit configured to connect first and second coupling terminals of the energy storage module to the terminals of the secondary winding of the transformer.

5. The balancing device according to claim 4, wherein the module switch unit comprises:

a first module switch configured to connect the first coupling terminal to one terminal of the secondary winding of the transformer; and

a second module switch configured to connect the second coupling terminal to another terminal of the secondary winding of the transformer.

6. The balancing device according to claim 2, wherein the cell switch unit, the polarity switch unit, and the auxiliary switch unit comprise two-way controllable switches.

7. The balancing device according to claim 1, wherein the switch network is controlled in a pulse width modulation (PWM) scheme to perform balancing.

8. The balancing device according to claim 1, wherein the switch network is controlled to use a winding, which is used for charging the transformer, when energy stored in the transformer is discharged.

9. The balancing device according to claim 1, wherein the switch network is controlled to discharge energy stored in the transformer using a winding, except for another winding used for charging the transformer, and to transfer energy from at least one energy storage unit to at least one energy storage unit.

10. The balancing device according to claim 1, wherein the switch network is controlled to discharge energy stored in the transformer using a winding, except for another winding used for charging the transformer, and to transfer energy between at least one energy storage unit and an energy storage module.

11. The balancing device according to claim 1, wherein the winding ratio of the primary winding and the secondary winding is 1:

T, and the switch network is controlled to vary a current gain, which is a ratio of a magnitude of discharging current of the transformer to a magnitude of charging current of the transformer, depending on selections of a winding for charging the transformer and a winding for discharging the transformer with respect to the winding ratio.

12. A balancing method for an energy storage module in which a plurality of energy storage units are connected in series, wherein a balancing device comprises a switch network and a transformer, the transformer comprises two windings, and the switch network comprises a plurality of switches which are configured to selectively connect each of four terminals of the two windings of the transformer to at least one of terminals of the plurality of energy storage units, the balancing method comprising an inductor mode operation and comprising the steps of:

allowing the transformer to be supplied with energy through one winding of the two windings from at least one of the energy storage units; and

allowing the transformer to supply energy to at least one of other energy storage units through the one winding used when energy is supplied.

13. The balancing method according to claim 12, wherein, in the inductor mode operation, current does not flow through the other winding of the two winding of the transformer.

14. The balancing method according to claim 12, wherein the at least one energy storage unit which supplies energy to the transformer in the inductor mode operation is the energy storage module.

15. The balancing method according to claim 12, wherein the at least one energy storage unit which is supplied with energy from the transformer in the inductor mode operation is the energy storage module.

16. The balancing method according to claim 12, wherein energy transference from at least one energy storage unit to at least one energy storage unit, from at least one energy storage unit to the energy storage module, and from the energy storage module to at least one energy storage unit is all possible by the inductor mode operation.

17. The balancing method according to claim 16, wherein, by a transformer mode operation utilizing a winding ratio of the two windings of the transformer, energy transference from at least one energy storage unit to at least one energy storage unit, from at least one energy storage unit to the energy storage module, and from the energy storage module to at least one energy storage unit is all possible.

18. A balancing device for balancing for a battery module comprising a plurality of battery cells connected in series to each other, the balancing device comprising:

a transformer comprising a primary and secondary windings; and

a switch network provided between the battery module and the primary and secondary windings of the transformer, and configured to comprise a plurality of switches for performing selectively switching,

wherein the switch network performs by selecting one mode among a mode for transferring energy from at least one battery cell to at least another battery cell, a mode for transferring energy from at least one battery cell to the battery module, and a mode for transferring energy from the battery module to at least another battery cell, according to selective switching of the plurality of switches.

19. The balancing device according to claim 18, wherein:

the primary and secondary windings of the transformer has a winding ratio; and

the switch network is configured to transfer energy through one of the primary and secondary windings of the transformer, or to transfer energy through a current gain by the winding ratio of the primary and secondary windings of the transformer.