VOLTAGE EQUALIZATION CIRCUIT FOR ELECTRIC ENERGY STORAGE DEVICE

• US 20110204722A1
• Filed: 10/19/2009
• Published: 08/25/2011
• Est. Priority Date: 10/27/2008
• Status: Abandoned Application

• Current Assignee: Kim's Techknowledge Inc.
• Original Assignee: Kims's Techknowledge Incorporated
• Inventors: Kim, Seong Min
• Application Number:
  US13/126,458
• Publication Number:
  US 20110204722A1
• Time in Patent Office: Days
• US Class Current: 307/77
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices

Abstract

The present invention is aimed at providing a simple and inexpensive device for equalizing voltage between electric energy storage cells such as batteries or capacitors connected in serial in an electric energy storage device. The invention provides a voltage equalization device that enables voltage equalization between the electric energy storage cells by transferring the electric energy of a high voltage electric energy storage cells to a low voltage electric energy storage cell through at least one voltage equalization cell. The voltage equalization circuit according to the invention comprises: a serial string of plural electric energy storage cells connected in a serial; at least one string of voltage equalization cells which includes at least one voltage equalization cell; plural 1^st switching units that connect the electric energy storage cells to the voltage equalization cells in parallel; at least one 2^nd switching unit that connects the serial string of electric energy storage cells to the string of voltage equalization cell in parallel; and a controller that controls the 1^st and 2^nd switching units, and restraining those two switching units from being in ON state simultaneously.

Claims

1. A voltage equalization circuit, comprising:

an electric energy storage cell serial string in which a plurality of electric energy storage cells are connected in series;

at least one voltage equalization cell string that includes at least one voltage equalization cell;

a plurality of first switching units that connects the electric energy storage cell with the voltage equalization cell in parallel;

at least one second switching unit that connects the electric energy storage cell serial string with the voltage equalization cell string in parallel; and

a controller that controls the first switching unit and the second switching unit and performs a control so that the first switching unit and the second switching unit are not simultaneously in an ON state.

2. The voltage equalization circuit of claim 1, wherein the control performs a control so that the first switching unit and the second switching unit are alternately in an ON state.

3. The voltage equalization circuit of claim 1, wherein the voltage equalization cell string includes the plurality of voltage equalization cells so as to correspond to the plurality of electric energy storage cells, respectively.

4. The voltage equalization circuit of claim 3, further comprising a third switching unit that connects the plurality of voltage equalization cells in series, wherein the third switching unit is controlled by the controller.

5. The voltage equalization circuit of claim 4, wherein the third switching unit is in an ON state when the second switching unit is in an ON state.

6. The voltage equalization circuit of claim 3, further comprising a current direction setting unit that is connected the electrice energy storage cell and the voltage equalization cell corresponding thereto in series.

7. The voltage equalization circuit of claim 6, wherein the current direction setting unit further includes a voltage detector that measures a potential difference between the electric energy storage cell and the voltage equalization cell.

8. The voltage equalization circuit of claim 3, wherein each of the plurality of voltage equalization cells are connected with a resistor in parallel.

9. The voltage equalization circuit of claim 1, further comprising a voltage detector that measures the voltage of the electric energy storage cell connected to the voltage equalization cell.

10. The voltage equalization circuit of claim 1, further comprising a discharge unit that is connected to the voltage equalization cell to discharge the electric energy storage cell when the voltage of the electric energy storage cell exceeds the predetermined value.

11. The voltage equalization circuit of claim 1, wherein the voltage equalization cell string includes at least one of voltage buffer cells connected with the voltage equalization cell in series.

12. The voltage equalization circuit of claim 11, wherein the voltage equalization cell string further includes a unit to prevent reverse polarity that is connected to the voltage buffer cell.

13. The voltage equalization circuit of claim 1, wherein the switching frequency of a first switching unit or a second switching unit is variable according to the voltage of the electric energy storage cell serial string.

14. The voltage equalization circuit of claim 1, wherein when the electric energy storage device and the voltage equalization circuit are divided into a plurality of modules, the divided voltage equalization circuits each include the controller.

15. The voltage equalization circuit of claim 14, wherein each controller of each of the divided voltage equalization circuits is operated by being synchronized.

16. The voltage equalization circuit of claim 14, wherein each controller of each of the divided voltage equalization circuits is operated by being asynchronized.

17. The voltage equalization circuit of claim 14, wherein each of the divided voltage equalization circuits includes a connection switch unit with the divided electric energy storage cells in order to provide the voltage equalization operation for the divided electric energy storage cell serial strings included in the module.

18. The voltage equalization circuit of claim 1, wherein the voltage equalization cell string includes at least one of an electric double layer capacitor, an aluminum electrolytic capacitor, and a tantalum electrolytic capacitor.