Structure and operation method of battery pack

• US 20040121223A1
• Filed: 11/26/2003
• Published: 06/24/2004
• Est. Priority Date: 11/29/2002
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Kim, Te-Hyun
• Granted Patent: US 7,790,307 B2
• Time in Patent Office: Days
• US Class Current: 429/61
• 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 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 50/202 Casings or frames around the primary casing of a single cell or a single battery
• CPC Class Codes: H01M 50/204 Racks, modules or packs for multiple batteries or multiple cells
• CPC Class Codes: H01M 50/269 Mechanical means for varying the arrangement of batteries or cells for different uses, e.g. for changing the number of batteries or for switching between series and parallel wiring methods or arrangements for servicing or maintenance H01M6/50, H01M10/42
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack for reducing a memory effect is disclosed. The battery pack includes at least one or more battery cells. A battery cell with the smallest residual voltage is selected from battery cells each having a residual voltage greater than a minimum threshold voltage, and first charged. Power is supplied to a terminal from a battery cell having the smallest residual voltage among battery cells having the residual voltage greater than the minimum threshold voltage, thereby lengthening a life span of the battery pack.

Claims

1. A battery pack comprising:

at least one or more battery cells;

first and second switches connected to each battery cell;

a switch controller for controlling the first and second switches;

a voltage measuring unit for measuring a voltage of a battery cell through the first and second switches; and

a controller for selecting one or several battery cells according to a residual voltage of each battery cell and a control signal of a terminal, and performing charging of a battery cell or supplying of power.

2. The battery pack of claim 1 further comprises:

an interface unit for interfacing an external terminal and a charging unit.

3. The battery pack of claim 2, wherein the interface unit comprises:

a power input terminal for transferring power supplied from the charging unit to the first switch;

a power supply unit for supplying power of a battery cell received through the second switch to the terminal;

a command input terminal for outputting a control signal of the terminal to the controller; and

a command output terminal for outputting result data of the controller to the terminal.

4. The battery pack of claim 1, wherein the first switch is a charge switch and the second switch is a supply switch.

5. The battery pack of claim 1, wherein the control signal of the terminal indicates a mode change, a switch manipulation and measurement of a residual voltage of a battery cell.

6. The battery pack of claim 1, wherein the controller comprises:

a voltage measuring unit for measuring a charge voltage and residual voltage of battery cells;

a command interpreting and controlling unit for performing a controlling operation according to the measurement voltage of the voltage measuring unit and a control signal of the terminal; and

a switch controller for controlling the first and second switches according to a control signal of the command interpreting and controlling unit.

7. The battery pack of claim 6, wherein the voltage measuring unit, the command interpreting and controlling unit and the switch controller is implemented as a low voltage logical circuit or as a microcomputer.

8. The battery pack of claim 1, wherein the controller depends only on the control signal of the terminal in a manual mode and performs charging of the battery cell or power supplying by itself according to the residual voltage of the battery cell regardless of the control signal in an automatic mode.

9. The battery pack of claim 8, wherein the controller selects and charges a battery cell having the least memory effect according to a residual voltage of the battery cell.

10. The battery pack of claim 9, wherein the controller charges battery cells in a sequential order beginning with those battery cells having the least memory effect according to residual voltages of battery cells.

11. The battery pack of claim 8, wherein the controller selects only those battery cells having a residual voltage greater than a minimum threshold voltage from a plurality of battery cells, and uses the selected battery cells for supplying power to the terminal.

12. The battery pack of claim 10, wherein the controller sequentially supplies power to the terminal using the battery cells beginning with the battery cell having the smallest residual voltage.

13. The battery pack of claim 8, wherein if the residual voltage of the battery cells is lower than the minimum threshold voltage, the controller is switched to a basic mode for performing charging and power supplying by connecting all the battery cells in parallel.

14. The battery pack of claim 8, wherein when there is an external request for a residual voltage measurement of a battery cell, the controller measures and reports a voltage of each battery cell.

15. A method for charging a battery pack having at least one or more battery cells and supplying power, comprising:

selecting a battery cell with the smallest memory effect from a plurality of battery cells and charging the selected battery cell; and

selecting a battery cell with the smallest memory effect from the charged plurality of battery cells and supplying power to a terminal.

16. The method of claim 15, wherein the charging step comprises:

measuring residual voltages of each battery cell;

comparing the measured residual voltages with the minimum threshold voltage; and

selecting a battery cell having the smallest residual voltage among residual voltages which are greater than the minimum threshold voltage and charging the selected battery cell.

17. The method of claim 16, wherein the residual voltage of the selected battery cell is greater than the minimum threshold value but smaller than a reference threshold voltage.

18. The method of claim 17, wherein the reference threshold voltage is the lowermost voltage in a range of maximum charge voltages.

19. The method of claim 16 further comprising:

connecting the plurality of battery cells in parallel and charging these battery cells if there is no residual voltage greater than a minimum discharge threshold voltage.

20. The method of claim 15, wherein the power supply step comprises:

measuring each residual voltage of the plurality of battery cells;

comparing the measured residual voltages with the minimum threshold voltage; and

supplying power of a battery cell, having the smallest residual voltage among residual voltages which are greater than the minimum threshold voltage, to the terminal.

21. The method of claim 20 further comprising:

connecting the plurality of battery cells in parallel and supplying power if there is no residual voltage greater than the minimum threshold voltage.

22. An operation method of a battery pack including at least one or more battery cells, comprising:

selecting a first battery cell according to a control signal inputted from a terminal;

charging the selected first battery cell;

selecting one or more second battery cells which have been previously charged according to a control signal of the terminal; and

supplying power of the selected second battery cell to the terminal.

23. The method of claim 22, wherein the first battery cell has the least memory effect.

24. The method of claim 22, wherein the first battery cell has the smallest residual voltage among battery cells which have a residual voltage greater than a minimum threshold voltage.

25. The method of claim 22, wherein the second battery cell has a residual voltage greater than the minimum threshold voltage.