Battery management system and method

• US 8,004,249 B2
• Filed: 12/19/2006
• Issued: 08/23/2011
• Est. Priority Date: 12/19/2005
• Status: Expired due to Fees

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Seo, Se-Wook, Lim, Gye-Jong, Yun, Han-Seok
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): Omar; Ahmed
• Application Number:
  US11/643,219
• Publication Number:
  US 20070139007A1
• Time in Patent Office: 1,708 Days
• Field of Search: 320/166, 320/116, 320/118, 324/428, 324/429, 324/431
• US Class Current: 320/166
• 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 adjacent to the first battery cell, the system comprising:

a first relay having first relay input terminals and first relay output terminals, the first relay input terminals configured to be 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 configured to be 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 first voltage transmitting unit output terminals, 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 through the first voltage transmitting unit output terminals in response to an on-voltage of a single third control signal, and to electrically disconnect the first voltage transmitting unit input terminals from the first voltage transmitting unit output terminals in response to an off-voltage of the third control signal;

a charging unit comprising a single capacitor having two capacitor input terminals, and a charging unit output terminal, the capacitor input terminals being respectively connected to the first voltage transmitting unit output terminals, the charging unit being configured to be charged to a voltage from the first voltage transmitting unit output terminals;

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 the 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;

separately assert the first and second control signals synchronously to the on-voltage of the third control signal before respectively measuring the voltage of the first battery cell and the voltage of the second battery cell; and

set the first, second, and third control signals as an off-voltage while measuring the voltage of the first battery cell and the voltage of the second battery cell,

wherein the charging unit is configured to be charged to the voltage of the first battery cell and to the voltage of the second battery cell as voltages having a same polarity, and

wherein voltages of different battery cells from among the plurality of battery cells are measured on consecutive assertions of the third control signal.

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 first voltage transmitting unit and the second voltage transmitting unit each includes a relay.

4. The system of claim 1, wherein the fourth control signal has an inverse voltage with respect to the third control signal.

5. The system of claim 4, further comprising a logic circuit configured to output the fourth control signal by inversing the third control signal.

6. The system of claim 4, further comprising a logic circuit configured to output the third control signal by inversing the fourth control signal.

7. 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.

8. The system of claim 7, further comprising a buffer configured to transmit the output voltage of the second voltage transmitting unit to the analog/digital converter.

9. The system of claim 7, 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.

10. 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 adjacent to the first battery cell, the method comprising:

charging a single capacitor having two terminals with a first battery cell voltage to a first capacitor voltage having a first polarity in response to an on-voltage of a first control signal for operating a first relay, an off-voltage of a second control signal for operating a second relay, and an on-voltage of a third control signal for operating a third relay, the first relay having first relay input terminals and first relay output terminals, the first relay input terminals respectively coupled to an anode and a cathode of the first battery cell, the second relay having second relay input terminals and second relay output terminals, the second relay input terminals respectively coupled to an anode and a cathode of the second battery cell, the third relay having third relay input terminals and third relay output terminals, the third relay input terminals respectively coupled to the first relay output terminals and the second relay output terminals, and the third relay output terminals respectively connected to the terminals of the capacitor;

measuring the first battery cell voltage using the first capacitor voltage in response to an off-voltage of the third control signal to electrically disconnect the third relay input terminals from the third relay output terminals;

charging the capacitor with a second battery cell voltage to a second capacitor voltage having the first polarity while the capacitor is charged with the first capacitor voltage having the same first polarity in response to an off-voltage of the first control signal, an on-voltage of the second control signal, and the on-voltage of the third control signal, to replace the first capacitor voltage with the second capacitor voltage; and

measuring the second battery cell voltage using the second capacitor voltage in response to the off-voltage of the third control signal,

wherein consecutive measurements of battery cell voltages are from different battery cells from among the plurality of battery cells.

11. The method of claim 10, 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.

12. The method of claim 11,

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

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

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

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

turning off the fourth relay; and

turning on the second relay while the fourth relay is turned off.

13. The method of claim 12,

wherein the measuring the first battery cell voltage using the first capacitor voltage includes:

turning off the first relay; and

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

wherein the measuring the second battery cell voltage using the second capacitor voltage includes;

turning off the second relay; and

turning on the fourth relay while the second relay is turned off.

14. The method of claim 12, wherein the turning off the fourth relay comprises turning on the third relay.

15. 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 single capacitor having two terminals, 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 as a first capacitor voltage having a first polarity in response to an on-voltage of a first control signal for operating a first relay, an off-voltage of a second control signal for operating a second relay, and an on-voltage of a third control signal for operating a third relay, the first relay having first relay input terminals and first relay output terminals, the first relay input terminals respectively coupled to an anode and a cathode of the first battery cell, the second relay having second relay input terminals and second relay output terminals, the second relay input terminals respectively coupled to an anode and a cathode of a second battery cell adjacent to the first battery cell among the plurality of battery cells of the corresponding one of the cell groups, the third relay having third relay input terminals and third relay output terminals, the third relay input terminals respectively coupled to the first relay output terminals and the second relay output terminals, and the third relay output terminals respectively connected to the terminals of the capacitor;

transmit the first capacitor voltage to the analog/digital converter in response to an off-voltage of the third control signal to electrically disconnect the third relay input terminals from the third relay output terminals;

charge a voltage of the second battery cell to the capacitor as a second capacitor voltage having the first polarity while the first capacitor voltage having the same first polarity is held in the capacitor in response to an off-voltage of the first control signal, an on-voltage of the second control signal, and the on-voltage of the third control signal, to replace the first capacitor voltage with the second capacitor voltage; and

transmit the second capacitor voltage to the analog/digital converter in response to the off-voltage of the third control signal,

wherein consecutive transmissions to the analog/digital converter of voltages charged to the capacitor are voltages charged to the capacitor by different battery cells from among the plurality of battery cells.

16. The system of claim 15, wherein each of the cell voltage measurers further includes a buffer configured to transmit the first capacitor voltage and the second capacitor voltage to the analog/digital converter.

17. The system of claim 15, 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.

18. The system of claim 15, 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.

19. The system of claim 15, 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.

20. 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 adjacent to the first battery cell; and

a battery management system,

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

charge a single capacitor having two terminals by the first battery cell with a first battery voltage to a first capacitor voltage having a first polarity in response to an on-voltage of a first control signal for operating a first relay, an off-voltage of a second control signal for operating a second relay, and an on-voltage of a third control signal for operating a third relay, the first relay having first relay input terminals and first relay output terminals, the first relay input terminals respectively coupled to an anode and a cathode of the first battery cell, the second relay having second relay input terminals and second relay output terminals, the second relay input terminals respectively coupled to an anode and a cathode of the second battery cell, the third relay having third relay input terminals and third relay output terminals, the third relay input terminals respectively coupled to the first relay output terminals and the second relay output terminals, and the third relay output terminals respectively connected to the terminals of the capacitor;

measure the first battery voltage from the capacitor in response to an off-voltage of the third control signal to electrically disconnect the third relay input terminals from the third relay output terminals;

charge the capacitor by the second battery cell with a second battery voltage to a second capacitor voltage having the first polarity while the capacitor holds the first capacitor voltage having the same first polarity in response to an off-voltage of the first control signal, an on-voltage of the second control signal, and the on-voltage of the third control signal, to replace the first capacitor voltage with the second capacitor voltage; and

measure the second battery voltage from the capacitor in response to the off-voltage of the third control signal,

wherein consecutive measurements of battery cell voltages from the capacitor are from different battery cells from among the plurality of battery cells.

21. The battery system of claim 20, 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.

22. The battery system of claim 21, wherein the cell voltage measurer comprise

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

23. The battery system of claim 21, 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.

24. The battery system of claim 21, 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.

25. The battery system of claim 21, further comprising a fuse coupled to a terminal of the battery.

26. The battery system of claim 20, wherein electrical energy is transmitted from the battery of the battery management system to operate a power generator of a vehicle.