Battery management system, battery management method, battery pack and electric vehicle

Patent metadata

Field	Value
Publication number	US-12308689-B2
Application number	US-202117783066-A
Country	US
Kind code	B2
Filing date	Jul 19, 2021
Priority date	Jul 20, 2020
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

A battery management system includes a voltage sensor to generate a voltage signal indicating a voltage of a battery, a current sensor to generate a current signal indicating a current flowing through the battery, and a control unit to record a voltage history and a current history of the battery based on the voltage signal and the current signal at a predetermined time interval during constant current charging of the battery. The control unit determines a differential capacity curve indicating a correlation between the voltage of the battery and a differential capacity in a reference voltage range. The control unit performs a first protection operation for the battery by comparing a first characteristic voltage of a main feature point with a reference voltage when the main feature point is detected from the differential capacity curve.

First claim

What is claimed is:

1. A battery management system, comprising:
a voltage sensor configured to generate a voltage signal indicating a voltage of a battery;
a current sensor configured to generate a current signal indicating a current flowing through the battery; and
a control unit configured to record a voltage history and a current history of the battery based on the voltage signal and the current signal at a predetermined time interval during constant current charging of the battery,
wherein the control unit is configured to:
determine a differential capacity curve indicating a correlation between the voltage of the battery and a differential capacity in a reference voltage range based on the voltage history and the current history;
detect a main feature point of the differential capacity curve; and
in a first protection operation for the battery, compare a first characteristic voltage of the main feature point with a reference voltage.

2. The battery management system according to claim 1 , wherein the main feature point is a first maximum point of the differential capacity curve during the constant current charging of the battery.

3. The battery management system according to claim 1 , wherein the control unit is configured to set, in the first protection operation:
a decreased cut-off voltage of the constant current charging, wherein the cut-off voltage is decreased by a compensation voltage corresponding to a voltage difference between the first characteristic voltage and the reference voltage, and
a lower limit of the cut-off voltage to an upper limit voltage of the reference voltage range.

4. The battery management system according to claim 1 , wherein the control unit is configured to set, in the first protection operation:
a decreased reference current of the constant current charging, wherein the reference current is decreased by a first compensation current corresponding to a voltage difference between the first characteristic voltage and the reference voltage.

5. The battery management system according to claim 4 , wherein the control unit is configured to:
detect a second feature point from the different capacity curve, the second feature point having a second characteristic voltage that is larger than the first characteristic voltage; and
perform a second protection operation for the battery in response to detection of the second feature point.

6. The battery management system according to claim 5 , wherein the control unit is configured to additionally decrease, in the second protection operation, the reference current.

7. The battery management system according to claim 1 , wherein the control unit is configured to stop the constant current charging in response to a feature point not being detected from the differential capacity curve.

8. The battery management system according to claim 1 , wherein the control unit is configured to determine the reference voltage range based on a maximum capacity of the battery.

9. A battery pack comprising the battery management system according to claim 1 .

10. An electric vehicle comprising the battery pack according to claim 9 .

11. A battery management method performed at a predetermined time interval during constant current charging of a battery, the battery management method comprising:
recording a voltage history and a current history of the battery based on a voltage signal indicating a voltage of the battery and a current signal indicating a current flowing through the battery;
determining a differential capacity curve indicating a correlation between the voltage of the battery and a differential capacity in a reference voltage range based on the voltage history and the current history;
detecting a main feature point of the differential capacity curve; and
in a first protection operation for the battery, comparing a first characteristic voltage of the main feature point with a reference voltage.

12. The battery management method according to claim 11 , further comprising:
detecting a second feature point of the differential capacity curve, the second feature point having a second characteristic voltage that is larger than the first characteristic voltage; and
performing a second protection operation for the battery in response to detecting the second feature point.

Assignees

• Lg Energy Solution Ltd

Inventors

• Cha A-Ming
• Bae Yoon-Jung
• Jeong Hee-Seok

Classifications

• H02J7/94

  in response to battery current · CPC title

• H02J7/963 Primary

  in response to battery voltage gradient · CPC title

• H02J7/933

  the cycle being controlled or terminated in response to electric parameters · CPC title

• H02J7/92

  with prioritisation of loads or sources · CPC title

• H02J7/64

  against overvoltage · CPC title