Battery management system and method

• US 20070139007A1
• Filed: 12/19/2006
• Published: 06/21/2007
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Seo, Se-Wook, Lim, Gye-Jong, Yun, Han-Seok
• Granted Patent: US 8,004,249 B2
• Time in Patent Office: Days
• US Class Current: 320/116
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: G01R 19/10 Measuring sum, difference or ratio
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• 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

A battery management system is provided. A voltage of a first battery cell is charged to a capacitor. Then, the voltage of the capacitor is measured, the measured voltage being the voltage of the first battery cell. Subsequently, a voltage of a second battery cell is again charged to the capacitor while the capacitor holds the voltage of the first battery cell. The voltage of the capacitor is then measured, the measured voltage being the voltage of the second battery cell. With such a scheme, the time for discharging the capacitor may be removed, and accordingly, a period for measuring a voltage of the battery cell may become shorter.

Claims

1. A system for managing a battery having a plurality of battery cells coupled in series, the plurality of battery cells including at least a first battery cell and a second battery cell, the system comprising:

a first relay having first relay input terminals and first relay output terminals, the first relay input terminals being respectively coupled to a first battery cell anode and to a first battery cell cathode, the first relay being configured to operate in response to a first control signal;

a second relay having second relay input terminals and second relay output terminals, the second relay input terminals being respectively coupled to a second battery cell anode and to a second battery cell cathode, the second relay being configured to operate in response to a second control signal;

a first voltage transmitting unit having first voltage transmitting unit input terminals and a first voltage transmitting unit output terminal, the first voltage transmitting unit input terminals being respectively coupled to the first relay output terminals and to the second relay output terminals, the first voltage transmitting unit being configured to output a voltage from the first voltage transmitting unit input terminals in response to an on-voltage of a third control signal;

a charging unit having a charging unit input terminal and a charging unit output terminal, the charging unit input terminal being coupled to the first voltage transmitting unit output terminal, the charging unit being configured to be charged to a voltage from the first voltage transmitting unit output terminal;

a second voltage transmitting unit having a second voltage transmitting unit input terminal and a second voltage transmitting unit output terminal, the second voltage transmitting unit input terminal being coupled to the charging unit output terminal, the second voltage transmitting unit being configured to output a voltage of the charging unit in response to an on-voltage of a fourth control signal; and

a control signal generator configured to set the voltage of the charging unit as a voltage of the second battery cell by setting the second control signal as an on-voltage while the voltage of the charging unit corresponds to a voltage of the first battery cell.

2. The system of claim 1, wherein the control signal generator is further configured to:

set the first control signal and the third control signal as an on-voltage and the second control signal and the fourth control signal as an off-voltage during a first period;

set the fourth control signal as an on-voltage and the first control signal, the second signal, and the third control signal as an off-voltage during a second period following the first period;

set the second control signal and the third control signal as an on-voltage and the first control signal and the fourth control signal as an off-voltage during a third period following the second period; and

set the fourth control signal as an on-voltage, and the first control signal, the second control signal, and the third control signal as an off-voltage during a fourth period following the third period.

3. The system of claim 1, wherein the charging unit includes at least one capacitor.

4. The system of claim 1, wherein the first voltage transmitting unit and the second voltage transmitting unit each includes a relay.

5. The system of claim 1, wherein

the fourth control signal has an inverse voltage with respect to the third control signal.

6. The system of claim 5, further comprising a logic circuit configured to output the fourth control signal by inversing the third control signal.

7. The system of claim 5, further comprising a logic circuit configured to output the third control signal by inversing the fourth control signal.

8. The system of claim 1, further comprising:

an analog/digital converter configured to convert an output voltage of the second voltage transmitting unit into a digital signal; and

a controller configured to measure voltages of the first battery cell and the second battery cell by using the digital signal from the analog/digital converter.

9. The system of claim 8, further comprising a buffer configured to transmit the output voltage of the second voltage transmitting unit to the analog/digital converter.

10. The system of claim 8, wherein the controller includes the control signal generator, the controller thus generating the first control signal, the second control signal, the third control signal, and the fourth control signal.

11. A method of managing a battery having a plurality of battery cells coupled in series, the plurality of battery cells including a first battery cell and a second battery cell, the method comprising:

charging a capacitor with a first battery cell voltage;

measuring the first battery cell voltage using the voltage charged to the capacitor corresponding to the first battery cell voltage;

charging the capacitor with a second battery cell voltage under a condition that the capacitor is charged with the first battery cell voltage; and

measuring the second battery cell voltage using the voltage charged to the capacitor corresponding to the second battery cell voltage.

12. The method of claim 11, wherein measuring the first battery cell voltage and the second battery cell voltage comprises:

outputting a capacitor voltage charged to the capacitor to a buffer;

converting a buffer output voltage into a digital signal; and

measuring the capacitor voltage using the converted digital signal.

13. The method of claim 12,

wherein charging the capacitor with the first battery cell voltage includes:

turning off a first relay coupled between the capacitor and the buffer; and

turning on a second relay coupled between the first battery cell and the capacitor while the first relay is turned off, and

wherein charging the capacitor with the second battery cell voltage under the condition that the capacitor is charged with the first battery cell voltage includes;

turning off the first relay; and

turning on a third relay coupled between the second battery cell and the capacitor while the first relay is turned off.

14. The method of claim 13,

wherein measuring the first battery cell voltage using the voltage charged to the capacitor corresponding to the first battery cell voltage includes:

turning off the second relay; and

turning on the first relay while the second relay is turned off, and

wherein measuring the second battery cell voltage using the voltage charged to the capacitor corresponding to the second battery cell voltage includes;

turning off the third relay; and

turning on the first relay while the third relay is turned off.

15. The method of claim 13, wherein turning off the first relay further comprises turning on a fourth relay coupled between the second relay and the third relay and the capacitor.

16. A system for managing a battery having a plurality of battery cells, the plurality of battery cells being divided into a plurality of cell groups, the system comprising:

a plurality of cell voltage measurers respectively coupled to the plurality of cell groups;

an analog/digital converter configured to convert voltages measured by the plurality of cell voltage measurers into digital signals; and

a controller configured to control charging and discharging of the plurality of battery cells included in each of the cell groups according to the digital signals converted by the analog/digital converter,

wherein each of the cell voltage measurers includes a capacitor and is configured to;

charge a voltage of a first battery cell among the plurality of battery cells of a corresponding one of the cell groups to the capacitor;

transmit a voltage charged to the capacitor by the first battery cell to the analog/digital converter;

charge a voltage of a second battery cell among the plurality of battery cells of a corresponding one of the cell groups to the capacitor while the voltage of the first battery cell is held in the capacitor; and

transmit a voltage charged to the capacitor by the second battery cell to the analog/digital converter.

17. The system of claim 16, wherein each of the cell voltage measurers further includes a buffer configured to transmit the voltage charged to the capacitor by the first battery cell and the voltage charged to the capacitor by the second battery cell to the analog/digital converter.

18. The system of claim 16, further comprising a cell voltage measurer configured to measure a voltage between an anode output terminal of the battery and a cathode output terminal of the battery and transmit the measured voltage to the analog/digital converter.

19. The system of claim 16, further comprising:

a current sensor configured to measure a current flowing through the plurality of battery cells; and

a cell current measurer configured to transmit a measured current to the analog/digital converter.

20. The system of claim 16, further comprising a temperature measurer configured to measure a temperature of the battery or a temperature of the periphery of the battery, and transmit a measured temperature to the controller.

21. A battery system comprising:

a battery having a plurality of battery cells coupled in series, the plurality of battery cells including a first battery cell and a second battery cell; and

a battery management system,

wherein the battery management system includes a cell voltage measurer configured to;

measure a capacitor voltage charged to a capacitor after the capacitor is charged by the first battery cell with a first battery voltage, and

measure the capacitor voltage after the capacitor is charged by the second battery cell with a second battery voltage, the capacitor being charged by the second battery cell while the capacitor holds a capacitor voltage equal to the first battery voltage.

22. The battery system of claim 21, further comprising:

an analog/digital converter configured to convert the capacitor voltage into a digital signal; and

a controller configured to measure a converted digital signal.

23. The battery system of claim 22, wherein the cell voltage measurer comprises:

a first relay coupled between a first battery cell anode and a first battery cell cathode and terminals of the capacitor, the first relay being configured to transmit the first battery voltage in response to a first control signal;

a second relay coupled between a second battery cell anode and a second battery cell cathode and the terminals of the capacitor, the second relay being configured to transmit the second battery voltage in response to a second control signal; and

a third relay having input terminals coupled to the terminals of the capacitor, the third relay being configured to transmit the capacitor voltage to the analog/digital converter in response to a third control signal.

24. The battery system of claim 22, further comprising a current sensor configured to sense a current flowing through the battery, and

wherein the battery management system further includes:

a battery current measurer configured to measure a current sensed by the current sensor and to transmit a measured current through the analog/digital converter to the controller;

a battery voltage measurer configured to measure a voltage between terminals of the battery, and to transmit a measured voltage through the analog/digital converter to the controller; and

a temperature measurer configured to measure a temperature of the battery or a temperature of a periphery of the battery.

25. The battery system of claim 22, further comprising:

a cooling fan controlled by the controller; and

a main switch coupled to a terminal of the battery and controlled by the controller.

26. The battery system of claim 22, further comprising a fuse coupled to a terminal of the battery.

27. The battery system of claim 21, wherein electrical energy is transmitted from the battery of the battery management system to operate a power generator of a vehicle.