VOLTAGE MEASURING APPARATUS AND BATTERY MANAGEMENT SYSTEM INCLUDING THE SAME

• US 20140239897A1
• Filed: 02/25/2014
• Published: 08/28/2014
• Est. Priority Date: 02/25/2013
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Fairchild Korea Semiconductor Limited (ON Semiconductor Corporation)
• Inventors: SONG, Moonsik, HEO, Seok
• Granted Patent: US 9,553,462 B2
• Time in Patent Office: Days
• US Class Current: 320/118
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• 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 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0034 using reverse polarity correcting or protecting circuits mechanical means of polarity protection H02J7/0045
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

Disclosed are a voltage measuring apparatus and a battery management system including the same. The voltage measuring apparatus is connected to a plurality of battery cells connected to each other in series to measure respective voltage of the battery cells. The voltage measuring apparatus includes a first node coupled to one of an positive electrode and a negative electrode of one of a plurality of battery cells as a voltage measuring target, amplifies a voltage difference between the first node and the second node to generate an error voltage, converts the error voltage into a digital signal, and compensates for a polarity of the digital signal.

Claims

1. A voltage measuring apparatus coupled to a plurality of battery cells coupled to each other in series to measure respective voltages of the battery cells, the voltage measuring apparatus comprising:

a first multiplexer configured to couple one of a positive electrode or a negative electrode of a battery cell among the battery cells serving as a voltage measuring target to a first node;

a second multiplexer configured to couple a remaining one of the positive electrode and the negative electrode of the battery cell serving as the voltage measuring target to a second node;

a flying capacitor coupled between the first node and the second node;

an error amplifier configured to amplify a voltage charged in the flying capacitor to generate an error voltage;

an analog-to-digital converter configured to convert the error voltage into a digital signal; and

a polarity correction unit configured to compensate a polarity of the digital signal.

2. The voltage measuring apparatus of claim 1, wherein the polarity correction unit is configured to output the digital signal as it is when the error voltage is a positive voltage and to invert the digital signal to output an inverted digital signal when the error voltage is a negative voltage.

3. The voltage measuring apparatus of claim 2, wherein the polarity correction unit comprises:

an inverter configured to invert each bit of the digital signal to generate an inverted digital signal; and

a polarity multiplexer configured to select one from the digital signal and the inverted digital signal according to a selection synchronous signal to output a correction digital signal.

4. The voltage measuring apparatus of claim 3, wherein the error amplifier comprises:

a non-inverting terminal coupled to the first node; and

an inverting terminal coupled to the second node.

5. The voltage measuring apparatus of claim 4, wherein when a positive electrode of a first battery cell among battery cells is coupled to the first node, and a negative electrode of the first battery cell is coupled to the second node,

the polarity multiplexer is configured to output the digital signal as the correction digital signal according to the selection synchronous signal.

6. The voltage measuring apparatus of claim 4, wherein when a negative electrode of a first battery cell among battery cells is coupled to the first node, and a positive electrode of the first battery cell is coupled to the second node,

the polarity multiplexer is configured to output the inverting digital signal as the correction digital signal according to the selection synchronous signal.

7. The voltage measuring apparatus of claim 2, wherein the polarity correction unit is configured to identify a polarity of the digital signal and configured to output one of the digital signal and the inverted digital signal according to the identified polarity of the digital signal.

8. The voltage measuring apparatus of claim 1, further comprising:

a relay configured to control a connection between the first node and a first input terminal of the error amplifier and a connection between the second node and a second input terminal of the error amplifier.

9. The voltage measuring apparatus of claim 8, wherein the relay comprises:

a first switch coupled between the first node and the first input terminal of the error amplifier; and

a second switch coupled between the second node and the second input of the error amplifier, and

wherein the flying capacitor is charged by the battery cell serving as the voltage measuring target, and then the first switch and the second switch are turned-on during a predetermined period.

10. A battery management system for managing a battery pack including a plurality of battery cells coupled to each other in series, the battery management system comprising:

a voltage measuring apparatus including a first node coupled to one of a positive electrode and a negative electrode of a battery cell among battery cells serving as a voltage measuring target and a second node coupled to a remaining one of the positive electrode and the negative electrode, and configured to amplify a voltage difference between the first node and the second node to generate an error voltage, to convert the error voltage to generate a digital signal, and to compensate a polarity of the digital signal; and

a controller configured to receive a correction digital signal having a compensated polarity to control charge and discharge of the battery pack.

11. The battery management system of claim 10, wherein the voltage measuring apparatus comprises:

a first multiplexer configured to couple the first node to one of a positive electrode and a negative electrode of the battery cell serving as the voltage measuring target;

a second multiplexer configured to couple the second node to a remaining one of the positive electrode and the negative electrode of the battery cell serving as the voltage measuring target;

a flying capacitor coupled between the first node and the second node;

an error amplifier configured to amplify a voltage charged in the flying capacitor to generate the error voltage;

an analog-to-digital converter configured to convert the error voltage into a digital signal; and

a polarity correction unit configured to compensate a polarity of the digital signal.

12. The battery management system of claim 11, wherein the polarity correction unit is configured to output the digital signal as it is when the error voltage is a positive voltage and to invert the digital signal to output the inverted digital signal when the error voltage is a negative voltage.

13. The battery management system of claim 12, wherein the polarity correction unit comprises:

an inverter configured to invert each bit of the digital signal to generate an inverted digital signal; and

a polarity multiplexer configured to select one from the digital signal and the inverted digital signal according to a selection synchronous signal to output a correction digital signal.

14. The battery management system of claim 13, wherein the error amplifier comprises:

a non-inverting terminal coupled to the first node; and

an inverting terminal coupled to the second node.

15. The battery management system of claim 14, wherein:

when a positive electrode of a first battery cell among battery cells is coupled to the first node, and a negative electrode of the first battery cell is coupled to the second node,

the polarity multiplexer is configured to output the digital signal as the correction digital signal according to the selection synchronous signal.

16. The battery management system of claim 14, wherein:

when an negative electrode of a first battery cell among battery cells is coupled to the first node, and a positive electrode of the first battery cell is coupled to the second node,

the polarity multiplexer is configured to output the inverting digital signal as the correction digital signal according to the selection synchronous signal.

17. The battery management system of claim 12, wherein:

the polarity correction unit is configured to identify a polarity of the digital signal and to output one of the digital signal and the inverted digital signal according to the identified polarity of the digital signal.

18. The battery management system of claim 11, wherein the voltage measuring apparatus, further comprises a relay configured to control connection between the first node and a first input terminal of the error amplifier and connection between the second node and a second input terminal of the error amplifier.

19. The battery management system of claim 18, wherein the relay comprises:

a first switch coupled between the first node and the first input terminal of the error amplifier; and

a second switch coupled between the second node and the second input of the error amplifier, and

wherein the flying capacitor is charged by the battery cell serving as the voltage measuring target, and then the first switch and the second switch are turned-on during a predetermined period.