Apparatus and method for diagnosing state of battery pack

Patent metadata

Field	Value
Publication number	US-12135356-B2
Application number	US-202017424280-A
Country	US
Kind code	B2
Filing date	Jul 10, 2020
Priority date	Jul 10, 2019
Publication date	Nov 5, 2024
Grant date	Nov 5, 2024

Abstract

The present disclosure relates to an apparatus and method for diagnosing a state of a battery pack, and more particularly, to an apparatus and method for diagnosing a state of a battery pack based on a SOC of a battery module included in the battery pack. According to the present disclosure, since the SOC of the battery module corresponding to an induced abnormal situation is estimated and the state of each battery module is diagnosed based on the estimated SOC, a risk factor that may occur in the battery module may be diagnosed in advance.

First claim

What is claimed is:

1. An apparatus for diagnosing a state of a battery pack, comprising:
a charging and discharging assembly configured to discharge and charge a plurality of battery modules having a plurality of battery cells connected to each other, in a plurality of cycles;
a monitoring assembly configured to measure a voltage or current of the plurality of battery modules in a fully charged state, in every cycle; and
a controller configured to, in every cycle:
change a number of battery cells included in the plurality of battery modules and connected to each other,
receive a measurement value for the voltage or current of the plurality of battery modules measured by the monitoring assembly,
estimate a state of charge (SOC) of each of the plurality of battery modules based on the received measurement value,
calculate a SOC change amount by comparing the estimated SOC of each of the plurality of battery modules with a preset reference value, and
diagnose a state of the plurality of battery modules based on the calculated SOC change amount and the changed number of battery cells included in the plurality of battery modules.

2. The apparatus for diagnosing the state of the battery pack according to claim 1 , wherein the controller is configured to change the number of battery cells included in the plurality of battery modules and connected to each other by:
selecting a target battery module among the plurality of battery modules,
selecting a target battery cell among the plurality of battery cells included in the selected target module, and
blocking a connection between the target battery cell and the remaining cells in the selected target battery module.

3. The apparatus for diagnosing the state of the battery pack according to claim 2 , wherein the controller is configured to select the target battery module in every cycle such that the selected target battery module does not overlap with a target battery module selected in a former cycle.

4. The apparatus for diagnosing the state of the battery pack according to claim 2 , wherein the controller is configured to, in every cycle, change a number of target battery cells selected in the target battery module.

5. The apparatus for diagnosing the state of the battery pack according to claim 2 , wherein the charging and discharging assembly is configured to discharge and charge battery cells connected to each other among the plurality of battery cells included in the plurality of battery modules.

6. The apparatus for diagnosing the state of the battery pack according to claim 1 , wherein the controller is configured to diagnose the state of each battery module as a normal state or a warning state according to a range of the calculated SOC change amount for each battery module, among a plurality of reference ranges set based on a number of total battery cells included in each battery module, and output the diagnosis result.

7. The apparatus for diagnosing the state of the battery pack according to claim 6 , wherein the controller is further configured to:
block a connection between the battery pack and the battery module among the plurality of battery modules whose state is diagnosed as the warning state,
re-estimate the SOC of the battery module disconnected from the battery pack after a predetermined time passes,
compare the re-estimated SOC with the preset reference value, and
output a diagnosis code based on the comparison result.

8. A battery pack, comprising the apparatus for diagnosing the state of the battery pack according to claim 1 .

9. A method for diagnosing a state of a battery pack, the method comprising:
changing a number of battery cells included in a plurality of battery modules and connected to each other, in every cycle;
discharging and charging the plurality of battery modules having a plurality of battery cells connected to each other, in every cycle;
measuring a voltage or current of the plurality of battery modules in a fully charged state;
estimating a state of charge (SOC) of each battery module based on the measured voltage or current;
calculating a SOC change amount by comparing the estimated SOC of each battery module with a preset reference value; and
diagnosing a state of the plurality of battery modules based on the calculated SOC change amount and the changed number of battery cells included in the plurality of battery modules.

10. The method for diagnosing the state of the battery pack according to claim 9 , further comprising, before the charging and discharging:
selecting a target battery module among the plurality of battery modules;
selecting a target battery cell among the plurality of battery cells included in the selected target battery module; and
blocking a connection between the target battery cell and the remaining cells in the selected target battery module.

11. The method for diagnosing the state of the battery pack according to claim 9 ,
wherein the diagnosing includes:
determining the state of each battery module as any one of a normal state and a warning state, based on a range to which the calculated SOC change amount belongs, among a plurality of reference ranges set based on a number of total battery cells included each battery module;
blocking a connection between the battery module determined as the warning state and the battery pack, as a result of the determination;
re-estimating the SOC of the battery module disconnected from the battery pack, after a predetermined time passes from the blocking the connection between the battery module determined as the warning state and the battery pack; and
comparing the re-estimated SOC with a predetermined reference value and outputting a diagnosis code based on the comparison result.

12. The method for diagnosing the state of the battery pack according to claim 10 , further comprising changing a number of target battery cells selected in every cycle.

13. The method for diagnosing the state of the battery pack according to claim 12 , comprising selecting the target battery module in every cycle so that the selected target battery module does not overlap with a target battery module selected in a former cycle.

Assignees

• Lg Energy Solution Ltd

Inventors

• Lee Dong-Chun
• Lee Won-Hoe
• Yoon Seog-Jin
• Lee Suk-Hoon

Classifications

• G01R31/388 Primary

  involving voltage measurements · CPC title

• G01R31/396

  Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery · CPC title

• H01M10/482 Primary

  for several batteries or cells simultaneously or sequentially · CPC title

• G01R31/3648

  comprising digital calculation means, e.g. for performing an algorithm · CPC title

• G01R31/3842

  combining voltage and current measurements · CPC title