Method and apparatus for diagnosing low voltage of secondary battery cell

Patent metadata

Field	Value
Publication number	US-11940501-B2
Application number	US-201917281361-A
Country	US
Kind code	B2
Filing date	Oct 4, 2019
Priority date	Oct 5, 2018
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

The present invention relates to a method and an apparatus for diagnosing low voltage of a secondary battery cell. The method for diagnosing low voltage of a secondary battery cell according to an embodiment of the present invention includes pre-aging a battery cell, charging the battery cell according to a preset charging condition, measuring a parameter for determining low voltage failure of the battery cell, comparing the measured parameter with a reference parameter, and performing formation when the battery cell is determined to be normal.

First claim

The invention claimed is:

1. A method for diagnosing low voltage failure of a secondary battery cell, the method comprising:
pre-aging a battery cell;
charging the battery cell to have a preset voltage according to a preset charging condition, wherein the preset voltage is set to a voltage of which a voltage change rate with respect to a state of charge (SOC) is greater than or equal to a preset reference value;
measuring a parameter for determining the low voltage failure of the battery cell;
comparing the measured parameter with a reference parameter to determine whether the battery cell is normal; and
subjecting the pre-aged battery cell to a subsequent charging under a predetermined voltage condition when the battery cell is determined to be normal, wherein the subsequent charging is an initial charging of a formation process.

2. The method of claim 1 , wherein the parameter is a charging duration from when the charging is started to when the battery cell reaches the preset voltage.

3. The method of claim 2 , wherein the charging duration is either a charging duration in a constant current mode, or a charging duration in a constant current charging interval of a constant current-constant voltage mode.

4. The method of claim 1 , wherein the parameter is a cumulative current amount accumulated from when the charging is started to when the battery cell reaches the preset voltage.

5. The method of claim 4 , wherein the cumulative current amount is measured in a constant current mode.

6. The method of claim 1 , wherein the parameter is a cumulative current amount accumulated from when the charging is started to when the battery cell reaches the preset voltage and a preset current.

7. The method of claim 6 , wherein the cumulative current amount is measured either in a constant current-constant voltage mode or in a constant current charging interval of the constant current-constant voltage mode.

8. The method of claim 1 , wherein the parameter is an amount of voltage drop of the battery cell from when the battery cell has reached the preset voltage and self-discharge is then started to a preset time.

9. The method of claim 1 , wherein the reference parameter is set differently depending on a type of the battery cell.

10. An apparatus for diagnosing low voltage failure of a secondary battery cell, the apparatus comprising:
a charging unit configured to charge a battery cell to have a preset voltage according to a preset charging condition, after a pre-aging process and before subjecting the pre-aged battery cell to a subsequent charging under a predetermined voltage condition, wherein the preset voltage is set to a voltage of which a voltage change rate with respect to a state of charge (SOC) is greater than or equal to a preset reference value, and wherein the subsequent charging is an initial charging of a formation process;
a measurement unit configured to measure a parameter for determining the low voltage failure of the battery cell; and
a control unit configured to compare the measured parameter with a reference parameter and determine the low voltage failure of the battery cell on the basis of a comparison result.

11. The apparatus of claim 10 , wherein the measurement unit measures, as the parameter, a charging duration from when the charging is started to when the battery cell reaches the preset voltage.

12. The apparatus of claim 11 , wherein the charging duration is measured either in a constant current mode or in a constant current charging interval of a constant current-constant voltage mode.

13. The apparatus of claim 10 , wherein the measurement unit measures, as the parameter, a cumulative current amount accumulated from when the charging is started to when the battery cell reaches the preset voltage.

14. The apparatus of claim 13 , wherein the cumulative current amount is measured in a constant current mode.

15. The apparatus of claim 10 , wherein the measurement unit measures, as the parameter, a cumulative current amount accumulated from when the charging is started to when the battery cell reaches the preset voltage and a preset current.

16. The apparatus of claim 15 , wherein the cumulative current amount is measured either in a constant current-constant voltage mode or in a constant current charging interval of the constant current-constant voltage mode.

17. The apparatus of claim 10 , wherein the measurement unit measures, as the parameter, an amount of voltage drop of the battery cell from when the battery cell has reached the preset voltage and self-discharge is then started to a preset time.

18. The apparatus of claim 10 , wherein the reference parameter is set differently depending on a type of the battery cell.

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Lee Yong Tae
• Ko Myung Hoon
• Kim Jee Ho
• Kang Gyung Soo

Classifications

• H02J7/80

  including monitoring or indicating arrangements · CPC title

• G01R31/3842 Primary

  combining voltage and current measurements · CPC title

• G01R31/3865 Primary

  related to manufacture, e.g. testing after manufacture · CPC title

• H01M10/44

  Methods for charging or discharging (circuits for charging H02J7/00) · CPC title

• H01M10/48

  Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) · CPC title