SYSTEMS AND METHODS FOR BALANCING MULTI-CELL BATTERIES

• US 20110140663A1
• Filed: 12/08/2010
• Published: 06/16/2011
• Est. Priority Date: 12/14/2009
• Status: Active Grant

• Current Assignee: Leach International Corporation (Transdigm Group Incorporated)
• Original Assignee: Leach International Corporation (Transdigm Group Incorporated)
• Inventors: Tran, Anhtai Le, Tofigh, Farshid
• Granted Patent: US 9,685,797 B2
• Time in Patent Office: Days
• US Class Current: 320/116
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits

Abstract

Systems and methods for balancing multi-cell batteries are provided. In one embodiment, the battery balancing circuit includes a battery including a plurality of cells coupled in series, a first terminal and a second terminal, a transformer including a primary winding and a plurality of secondary windings, where each secondary winding is coupled to one of the plurality of cells via a secondary switch and a rectifier circuit, where the primary winding is coupled between the first terminal and the second terminal of the battery, a primary switch in series with the primary winding of the transformer, and a control circuitry coupled to the primary switch, the plurality of secondary switches, and each of the plurality of cells.

Claims

1. A battery balancing circuit comprising:

a battery comprising a plurality of cells coupled in series, a first terminal and a second terminal;

a transformer comprising a primary winding and a plurality of secondary windings, wherein each secondary winding is coupled to one of the plurality of cells via a secondary switch and a rectifier circuit, wherein the primary winding is coupled between the first terminal and the second terminal of the battery;

a primary switch in series with the primary winding of the transformer; and

a control circuitry coupled to the primary switch, the plurality of secondary switches, and each of the plurality of cells.

2. The circuit of claim 1, wherein the control circuitry is configured to:

detect an imbalance condition in at least one cell of the plurality of cells; and

actuate the primary switch and at least one secondary switch of the plurality of secondary switches such that energy is transferred from the battery to the at least one cell.

3. The circuit of claim 2, wherein the control circuitry is configured to:

measure a voltage at each of the plurality of cells;

identify a cell of the plurality of cells having a voltage below a preselected threshold;

actuate a secondary switch coupled to the identified cell; and

actuate, repeatedly, the primary switch such that energy is transferred from the battery to the identified cell.

4. The circuit of claim 2, wherein the control circuitry is configured to actuate the primary switch at a preselected frequency and with a preselected duty cycle.

5. The circuit of claim 2, wherein the imbalance condition is selected from the group consisting of an under-voltage and an over-voltage.

6. The circuit of claim 1, wherein the control circuitry is configured to:

detect a level of charge in each of the plurality of cells;

energize the primary winding by switching the primary switch; and

provide a path for energy from the primary winding to at least one cell of the plurality of cells by switching at least one corresponding secondary switch of the plurality of second switches.

7. The circuit of claim 1, wherein each of the rectifier circuits comprise a full wave rectifier.

8. The circuit of claim 7, wherein the full wave rectifier comprises a center tapped full wave rectifier including at least two diodes.

9. The circuit of claim 1, wherein each secondary winding is connected to a corresponding rectifier circuit and a corresponding secondary switch is connected between the corresponding rectifier circuit and a corresponding cell of the battery.

10. The circuit of claim 1, wherein each of the rectifier circuits consist of a diode.

11. A battery balancing circuit comprising:

a battery comprising a plurality of cells coupled in series, a first terminal and a second terminal;

a transformer comprising a primary winding and a plurality of secondary windings, wherein each secondary winding is coupled to one of the plurality of cells via a secondary switch and a rectifier circuit, wherein a center-tap terminal of the primary winding is coupled to the first terminal of the battery;

a first primary switch coupled in series between a first terminal of the primary winding and the second terminal of the battery;

a second primary switch coupled in series between a second terminal of the primary winding and the second terminal of the battery; and

a control circuitry coupled to the first primary switch, the second primary switch, the plurality of secondary switches, and each of the plurality of cells.

12. The circuit of claim 11, wherein the control circuitry is configured to:

detect an imbalance condition in at least one cell of the plurality of cells; and

actuate the first primary switch, the second primary switch and at least one secondary switch of the plurality of secondary switches such that energy is transferred from the battery to the at least one cell.

13. The circuit of claim 12, wherein the control circuitry is configured to:

measure a voltage at each of the plurality of cells;

identify a cell of the plurality of cells having a voltage below a preselected threshold;

actuate a secondary switch coupled to the identified cell; and

actuate, repeatedly, the first primary switch and the second primary switch whereby energy is transferred from the battery to the identified cell.

14. The circuit of claim 12, wherein the control circuitry is configured to actuate the first primary switch and second primary switch at a preselected frequency and with a preselected duty cycle.

15. The circuit of claim 12, wherein the imbalance condition is selected from the group consisting of an under-voltage and an over-voltage.

16. The circuit of claim 11, wherein a first control line is coupled between the control circuitry and the first primary switch and wherein an inverter is coupled between the first control line and the second primary switch.

17. The circuit of claim 11, wherein the control circuitry is configured to:

detect a level of charge in each of the plurality of cells;

energize the primary winding by switching the first primary switch and the second primary switch; and

provide a path for energy from the primary winding to at least one cell of the plurality of cells by switching at least one corresponding secondary switch of the plurality of second switches.

18. The circuit of claim 11, wherein each of the rectifier circuits comprise a full wave rectifier.

19. The circuit of claim 18, wherein the full wave rectifier comprises a center tapped full wave rectifier including at least two diodes.

20. The circuit of claim 11, wherein each secondary winding is connected to a corresponding rectifier circuit and a corresponding secondary switch is connected between the corresponding rectifier circuit and a corresponding cell of the battery.

21. The circuit of claim 11, wherein each of the rectifier circuits consist of a diode.

22. A method for balancing energy stored in a plurality of cells of a battery having a first terminal and a second terminal, the method comprising:

detecting an imbalance condition in one of the plurality of cells of the battery;

actuating, repeatedly, a primary switch coupled between the first terminal of the battery and a transformer comprising a primary winding and a plurality of secondary windings, wherein each secondary winding is coupled to one of the plurality of cells via a secondary switch and a rectifier circuit, wherein the primary winding is coupled between the first terminal and the second terminal of the battery; and

actuating the secondary switch corresponding to the one of the plurality of battery cells having the imbalance condition.