BATTERY STACK BALANCING APPARATUS

• US 20180040922A1
• Filed: 07/13/2016
• Published: 02/08/2018
• Est. Priority Date: 07/23/2015
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: SUNG, Chang-Hyun, LEE, Sang-Hoon
• Granted Patent: US 10,446,880 B2
• Time in Patent Office: Days
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 10/4257 Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries
• CPC Class Codes: H01M 10/4264 with capacitors
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 50/204 Racks, modules or packs for multiple batteries or multiple cells
• CPC Class Codes: H01M 50/51 Connection only in series
• CPC Class Codes: H01M 50/512 Connection only in parallel
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Disclosed is a balancing apparatus capable of performing balancing without wasting power and of rapidly transmitting power. A battery stack balancing apparatus for balancing a battery stack including a plurality of battery modules connected to each other in series includes a series resonant circuit including a first capacitor and a first inductor connected to the first capacitor in series, a polarity change circuit including a second inductor and a polarity change switch connected to the second inductor in series so as to be selectively turned on or off, and connected to the first capacitor in parallel, a plurality of transmission lines having ends, respectively, electrically connected to a plurality of nodes provided at a low-potential end of the battery stack, at a high-potential end of the battery stack, and between the plurality of battery modules connected to each other in series, and other ends connected to the series resonant circuit, a plurality of transmission switches provided on the plurality of transmission lines so as to be selectively turned on or off, and a control unit configured to control the plurality of transmission switches and the polarity change switch.

Claims

1. A battery stack balancing apparatus for balancing a battery stack comprising a plurality of battery modules connected to each other in series, the apparatus comprising:

a series resonant circuit comprising a first capacitor and a first inductor connected to the first capacitor in series;

a polarity change circuit comprising a second inductor and a polarity change switch connected to the second inductor in series so as to be selectively turned on or off, and connected to the first capacitor in parallel;

a plurality of transmission lines having ends, respectively, electrically connected to a plurality of nodes provided at a low-potential end of the battery stack, at a high-potential end of the battery stack, and between the plurality of battery modules connected to each other in series, and other ends connected to the series resonant circuit;

a plurality of transmission switches provided on the plurality of transmission lines so as to be selectively turned on or off; and

a control unit configured to control the plurality of transmission switches and the polarity change switch.

2. The battery stack balancing apparatus of claim 1, wherein the other ends of the plurality of transmission lines are alternately connected to an end and another end of the series resonance circuit.

3. The battery stack balancing apparatus of claim 2, wherein the control unit controls the plurality of transmission switches in such a manner that zero current switching or zero voltage switching is performed in accordance with a half period of a resonance period of the series resonant circuit.

4. The battery stack balancing apparatus of claim 2, wherein the control unit controls the polarity change switch in such a manner that zero current switching or zero voltage switching is performed in accordance with a half period of a resonance period of a parallel resonant circuit formed by the first capacitor and the second inductor when the polarity change switch is turned on.

5. The battery stack balancing apparatus of claim 2, wherein the control unit controls the polarity change switch and the plurality of transmission switches by comparing a polarity of a voltage of at least one battery module for supplying power to the series resonant circuit, to a polarity of a voltage charged in the first capacitor.

6. The battery stack balancing apparatus of claim 5, wherein the control unit controls the polarity change switch to be turned on and controls all of the plurality of transmission switches to be turned off, when the polarity of the voltage of the at least one battery module for supplying power to the series resonant circuit equals the polarity of the voltage charged in the first capacitor.

7. The battery stack balancing apparatus of claim 2, wherein the control unit controls the polarity change switch and the plurality of transmission switches by comparing a polarity of a voltage of at least one battery module for receiving power supplied from the series resonant circuit, to a polarity of a voltage charged in the first capacitor.

8. The battery stack balancing apparatus of claim 7, wherein the control unit controls the polarity change switch to be turned off, controls two transmission switches connected to two ends of the at least one battery module for receiving power supplied from the series resonant circuit, to be turned on, and controls transmission switches other than the two transmission switches to be turned off, when the polarity of the voltage of the at least one battery module for receiving power supplied from the series resonant circuit equals the polarity of the voltage charged in the first capacitor.

9. The battery stack balancing apparatus of claim 7, wherein the control unit controls the polarity change switch to be turned on and controls all of the plurality of transmission switches to be turned off, when the polarity of the voltage of the at least one battery module for receiving power supplied from the series resonant circuit differs from the polarity of the voltage charged in the first capacitor.

10. The battery stack balancing apparatus of claim 1, wherein each of the battery modules is a unit battery cell or an assembly of two or more battery cells.

11. A battery pack comprising the battery stack balancing apparatus of claim 1.

12. An electric vehicle comprising the battery stack balancing apparatus of claim 1.