BALANCING CONTROL CIRCUIT FOR BATTERY CELL MODULE USING LC SERIES RESONANT CIRCUIT

• US 20140340022A1
• Filed: 10/28/2013
• Published: 11/20/2014
• Est. Priority Date: 05/16/2013
• Status: Active Grant

• Current Assignee: Postech Academy-Industry Foundation
• Original Assignee: Postech Academy-Industry Foundation
• Inventors: Kang, Bong Koo, Sung, Chang Hyeon, Choe, Hyung Jin, Yoon, Ho Young, Cho, Min Gi, Chung, Yoo Chae, Lee, Kyung Min
• Granted Patent: US 9,203,246 B2
• Time in Patent Office: Days
• US Class Current: 320/103
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Provided is a battery cell balancing circuit including: a battery cell module including a plurality of battery cells connected in series; a series resonant circuit including an inductor unit and a capacitor unit which are connected in series so as to store electric energy recovered from a corresponding battery cell of the battery cell module and supply the stored electric energy to a corresponding battery cell of the battery cell module; and a switch unit configured to provide an electric energy recovery path for storing the electric energy recovered from the corresponding battery cell of the battery cell module into the capacitor unit of the series resonant circuit and provide an electric energy supply path for supplying the stored electric energy to the corresponding battery cell of the battery cell module.

Claims

1. A battery cell balancing circuit comprising:

a battery cell module comprising a plurality of battery cells connected in series;

a series resonant circuit comprising an inductor unit and a capacitor unit which are connected in series so as to store electric energy recovered from a corresponding battery cell of the battery cell module and supply the stored electric energy to a corresponding battery cell of the battery cell module; and

a switch unit configured to provide an electric energy recovery path for storing the electric energy recovered from the corresponding battery cell of the battery cell module into the capacitor unit of the series resonant circuit and provide an electric energy supply path for supplying the stored electric energy to the corresponding battery cell of the battery cell module.

2. The battery cell balancing circuit of claim 1, wherein one or more of the inductor unit and the capacitor unit have a variable capacity.

3. The battery cell balancing circuit of claim 1, wherein the inductor unit comprises:

a plurality of inductors; and

one or more switches configured to connect an arbitrary number of inductors in parallel to each other among the plurality of inductors.

4. The battery cell balancing circuit of claim 1, wherein the inductor unit comprises:

a first inductor;

a second inductor; and

a 21st switch configured to perform a switching operation such that the first and second inductors are connected in parallel to each other or separated from each other.

5. The battery cell balancing circuit of claim 1, wherein the capacitor unit comprises:

a plurality of capacitors; and

one or more switches configured to connect an arbitrary number of capacitors in parallel to each other among the plurality of capacitors.

6. The battery cell balancing circuit of claim 1, wherein the capacitor unit comprises:

a first capacitor;

a second capacitor; and

a 22nd switch configured to perform a switching operation such that the first and second capacitors are connected in parallel to each other or separated from each other.

7. The battery cell balancing circuit of claim 1, wherein the switch unit comprises:

a first switch unit comprising a plurality of switches connected between a first common node and one terminals of the plurality of battery cells, respectively;

a second switch unit comprising a plurality of switches connected between a second common node and the other terminals of the plurality of battery cells, respectively; and

a third switch unit comprising switches connected between the first common node and both terminals of the series resonant circuit and switches connected between the second common node and both terminals of the series resonant circuit.

8. The battery cell balancing circuit of claim 7, wherein the respective switches of the first to third switch units comprise one or more of an SPST (single pole single throw) switch and a MOS transistor.

9. The battery cell balancing circuit of claim 1, wherein the electric energy recovered from the corresponding battery cell of the battery cell module comprises electric energy recovered from a battery cell storing the highest electric energy among the battery cells of the battery cell module.

10. The battery cell balancing circuit of claim 1, wherein the battery cell receiving the stored electric energy comprises a battery cell storing the lowest electric energy among the battery cells of the battery cell module.

11. A battery cell balancing circuit using an LC series resonant circuit, comprising a plurality of battery modules,

wherein each of the battery modules comprises:

a battery cell module comprising a plurality of battery cells connected in series;

a series resonant circuit configured to store electric energy recovered from a corresponding battery cell of the battery cell module and supply the stored electric energy to a corresponding battery cell of the battery cell module;

a switch unit configured to provide an electric energy recovery path for storing the electric energy recovered from the corresponding battery cell of the battery cell module into a capacitor of the series resonant circuit and provide an electric energy supply path for supplying the stored electric energy to a corresponding battery cell of the battery cell module; and

a coil of a transformer connected in parallel to the capacitor,

the battery cell modules are connected in series, and

the coils included in the series resonant circuits are magnetically coupled so that the levels of electric energies stored in or discharged from the capacitors are varied at the same level.

12. The battery cell balancing circuit of claim 11, wherein the switch unit comprises:

a first switch unit comprising a plurality of switches connected between a first common node and one terminals of the plurality of battery cells, respectively;

a second switch unit comprising a plurality of switches connected between a second common node and the other terminals of the plurality of battery cells, respectively; and

a third switch unit comprising a plurality of switches connected between the first common node and both terminals of the series resonant circuit and a plurality of switches connected between the second common node and both terminals of the series resonant circuit.

13. The battery cell balancing circuit of claim 12, wherein the respective switches of the first to third switch units comprise one or more of an SPST switch and a MOS transistor.

14. The battery cell balancing circuit of claim 11, wherein the switch unit forms a path for alternately supplying a voltage to the coil of the transformer in both directions, when the electric energy recovered from the corresponding battery cell of the battery cell module is stored and the stored electric energy is supplied to the corresponding battery cell of the battery cell module.

15. The battery cell balancing circuit of claim 11, wherein the coil of the transformer is separated from the capacitor when a separate electric energy balancing operation is performed in the corresponding battery module and connected to the capacitor when electric energy exchange is required between the battery modules after the separate electric energy balancing operation, through a select switch.

16. The battery cell balancing circuit of claim 11, wherein each of the battery cells has a larger capacity by a predetermined value than the capacitor.

17. The battery cell balancing circuit of claim 11, wherein the electric energy recovered from the corresponding battery cell of the battery cell module comprises electric energy recovered from a battery cell storing the highest electric energy among the battery cells of the battery cell module.

18. The battery cell balancing circuit of claim 11, wherein the battery cell receiving the stored electric energy comprises a battery cell storing the lowest electric energy among the battery cells of the battery cell module.