Charge equalization apparatus

• US 8,120,322 B2
• Filed: 02/05/2008
• Issued: 02/21/2012
• Est. Priority Date: 02/09/2007
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology, SK On Company Limited (SK Innovation Company Limited)
• Original Assignee: Korea Advanced Institute of Science and Technology, SK Energy Co Ltd (SK Innovation Company Limited)
• Inventors: Lee, Joong Hui, Jang, Soo Yeup, Oh, Jeon Keun, Moon, Gun Woo, Kim, Chong Eun, Park, Hong Sun, Kim, Chol Ho
• Primary Examiner(s): RAMADAN, RAMY O
• Application Number:
  US12/449,313
• Publication Number:
  US 20100148726A1
• Time in Patent Office: 1,477 Days
• Field of Search: None
• US Class Current: 320/118
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

The present invention relates to a charge equalization apparatus, in which series-connected batteries are divided into modules having certain sizes, and intra-module charge equalization and inter-module charge equalization are simultaneously performed, thus improving charge equalization performance and reducing the circuit size.

Claims

1. A charge equalization apparatus for equalizing charges of M*N batteries, the charge equalization apparatus being configured such that the M*N batteries are connected in series and are divided into N battery modules, each having M series-connected batteries, comprising:

N intra-module charge equalization units, each connected in parallel with respective M series-connected batteries existing in each battery module, supplied with charge from the M series-connected batteries, and configured to discharge overcharged batteries and to charge undercharged batteries, thus equalizing charges of the M series-connected batteries;

an inter-module charge equalization unit connected in parallel with respective N battery modules and configured to discharge overcharged battery modules, among the N battery modules, and to charge undercharged battery modules, thus equalizing charges of the N battery modules;

a voltage detection and drive signal generation unit configured to detect voltages of respective M*N batteries, to set an average voltage of the detected voltages as a reference voltage, to generate a drive signal using both the detected voltages and the reference voltage, and to control driving of the N intra-module charge equalization units and the inter-module charge equalization unit by providing the generated drive signal to the N intra-module charge equalization units and the inter-module charge equalization unit; and

wherein each of the N intra-module charge equalization units comprises;

M first transformer units respectively connected in parallel with the M series-connected batteries, and configured to store a charge supplied by the M series-connected batteries and to supply the stored charge to undercharged batteries among the M series-connected batteries, thus equalizing charges of the M series-connected batteries;

M charge/discharge control switches connected between first ends of primary windings of the first transformer units and an anode of a first battery of the M series-connected batteries so as to supply a charge supplied by the M series-connected batteries to the primary windings of the transformer units; and

M first semiconductor switching devices connected between first ends of secondary windings of the first transformer units and anodes of the M series-connected batteries so as to prevent a charge supplied by the M series-connected batteries from being supplied to the secondary windings of the first transformer units.

2. The charge equalization apparatus according to claim 1, wherein each of the first transformer units comprises:

a first transformer connected in parallel with a corresponding one of the M series-connected batteries and configured to store a charge supplied by the M series-connected batteries and to supply the stored charge to undercharged batteries among the M series-connected batteries;

a first inductor connected between a first end of a primary winding of the first transformer and a corresponding one of the charge/discharge control switches; and

a second inductor connected between both ends of the primary winding of the first transformer so as to store a charge supplied by the M series-connected batteries in a form of magnetizing current.

3. The charge equalization apparatus according to claim 1, wherein the charge/discharge control switches are bidirectional switches.

4. The charge equalization apparatus according to claim 3, wherein the charge/discharge control switches are solid-state relays.

5. The charge equalization apparatus according to claim 1, wherein, in each of the first transformer units, a turns ratio of the primary winding to the secondary winding is N1:

N2.

6. The charge equalization apparatus according to claim 5, wherein each of the first transformer units is configured such that a dot formed on the primary winding and a dot formed on the secondary winding are placed on different sides.

7. The charge equalization apparatus according to claim 5, wherein each of the first transformer units is configured such that a dot formed on the primary winding and a dot formed on the secondary winding are placed on a same side.

8. The charge equalization apparatus according to claim 1, wherein the inter-module charge equalization unit comprises:

N second transformer units connected in parallel with the N series-connected battery modules and configured to store a charge, supplied by the N series-connected battery modules, and to supply the stored charge to undercharged battery modules, among the N series-connected battery modules, thus equalizing charges of the N series-connected battery modules; and

N first redistribution switches connected between second ends of primary windings of the second transformer units and cathodes of last batteries of respective battery modules in order to form closed loops so that a charge supplied by the battery modules is supplied to the primary windings of the first transformer units and the primary windings of the second transformer units.

9. The charge equalization apparatus according to claim 8, wherein each of the second transformer units comprises:

a second transformer connected in parallel with a corresponding one of the N series-connected battery modules and configured to store a charge, supplied by the N series-connected battery modules, and to supply the stored charge to undercharged battery modules among the N series-connected battery modules;

a third inductor connected between a first end of a primary winding of the second transformer and an anode of a first battery of a corresponding battery module; and

a fourth inductor connected between both ends of the primary winding of the second transformer so as to store a charge, supplied by the N series-connected battery modules, in a form of magnetizing current.

10. The charge equalization apparatus according to claim 8, wherein, in each of the second transformer units, a number of turns of a primary winding and a number of turns of a secondary winding are identical to each other.

11. The charge equalization apparatus according to claim 8, wherein each of the second transformer units is configured such that a dot formed on the primary winding and a dot formed on the secondary winding are placed on different sides.

12. The charge equalization apparatus according to claim 8, wherein each of the first transformer units is configured such that a dot formed on the primary winding and a dot formed on the secondary winding are placed on a same side.

13. The charge equalization apparatus according to claim 8, wherein the intra-module charge equalization units further comprise respective N second redistribution switches connected between common nodes of primary windings of the first transformer units and cathodes of last batteries of respective battery modules so as to form a closed loop so that a charge supplied by the battery modules is supplied to the primary windings of the first transformer units.

14. The charge equalization apparatus according to claim 13, wherein the inter-module charge equalization unit further comprises a second semiconductor switching device connected between an anode of a first battery of the M*N series-connected batteries and a common node of first ends of the secondary windings of the second transformer units so as to supply magnetizing current supplied by fourth inductors to the N series-connected battery modules.

15. The charge equalization apparatus according to claim 13, wherein the first redistribution switches and the second redistribution switches are Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), Bipolar Junction Transistors (BJTs), or relays.

16. The charge equalization apparatus according to claim 15, wherein the first redistribution switches and the second redistribution switches are N-type MOSFETs.

17. The charge equalization apparatus according to claim 14, wherein the first redistribution switches and the second redistribution switches are MOSFETs, BJTs, relays or diodes.

18. The charge equalization apparatus according to claim 17, wherein the first semiconductor switching devices and the second semiconductor switching devices are diodes.

19. The charge equalization apparatus according to claim 1, wherein the voltage detection and drive signal generation unit comprises:

a sensing unit for detecting voltages of each of the respective M*N batteries;

a microprocessor for setting the average voltage of the voltages detected by the sensing unit as the reference voltage, and setting ON/OFF times of charge/discharge control switches and redistribution switches on the basis of the reference voltage and the voltages detected by the sensing unit; and

a switch driving circuit unit for generating the drive signal required to drive the charge/discharge control switches and the redistribution switches on the basis of a signal input from the microprocessor.