Battery management apparatus, battery management method, and energy storage system including the battery management apparatus

Patent metadata

Field	Value
Publication number	US-11205905-B2
Application number	US-201916649100-A
Country	US
Kind code	B2
Filing date	Feb 11, 2019
Priority date	May 3, 2018
Publication date	Dec 21, 2021
Grant date	Dec 21, 2021

Abstract

Provided is a battery management apparatus, a battery management method and an energy storage system including the same. The battery management apparatus according to an embodiment of the present disclosure includes a first battery pack, a second battery pack, a first switch connected in series to the first battery pack between a first terminal and a second terminal, a second switch connected in series to the second battery pack between the first terminal and the second terminal, and a control unit. The control unit is configured to turn on both the first switch and the second switch when a voltage difference between the first battery pack and the second battery pack at a time point at which both the first switch and the second switch are turned off is less than a threshold voltage.

First claim

What is claimed is:

1. A battery management apparatus connectable to a power conversion system through a first terminal and a second terminal of the power conversion system, the battery management apparatus comprising:
a first battery pack;
a second battery pack;
a first switch connected to the first battery pack between the first terminal and the second terminal;
a second switch connected to the second battery pack between the first terminal and the second terminal; and
a control unit configured to:
determine whether a pack current of the first battery pack and a pack current of the second battery pack are within a preset current range in a shutdown preparation mode in response to a first notification signal from the power conversion system, while any one of balancing steps for parallel connection between the first battery pack and the second battery pack is performed; and
turn off the first switch and the second switch when the pack current of the first battery pack and the pack current of the second battery pack are determined to be within the preset current range,
wherein the balancing steps, performed by the control unit, comprise:
determining whether a voltage difference between the first battery pack and the second battery pack is less than a first threshold voltage,
when the voltage difference is less than the first threshold voltage, turning on both the first switch and the second switch to connect the first battery pack and the second battery pack in parallel, and
when the voltage difference is greater than or equal to the first threshold voltage:
turning on the first switch and maintaining the second switch in a turn off state, and
determining whether a state of charge (SOC) difference between the first battery pack and the second battery pack is less than a threshold SOC.

2. The battery management apparatus according to claim 1 , wherein the control unit is further configured to execute the shutdown preparation mode at a time point at which a preset preparation period has passed from a time point at which the first notification signal was received by the control unit.

3. The battery management apparatus according to claim 2 , wherein:
the preset preparation period is equal to or longer than a tracking period of the power conversion system; and
the tracking period indicates a minimum time required for the power conversion system to reduce power supplied between the first terminal and the second terminal down to 0 W.

4. The battery management apparatus according to claim 2 , wherein the control unit is further configured to resume one of the balancing steps being performed at the time point at which the first notification signal was received, when a second notification signal from the power conversion system is received before the preset preparation period has passed from the time point at which the first notification signal was received.

5. The battery management apparatus according to claim 1 , wherein the control unit is further configured to execute a current diagnosis mode for monitoring each of the pack current of the first battery pack and the pack current of the second battery pack for an indefinite time, when at least one of the pack current of the first battery pack and the pack current of the second battery pack at a time point at which the shutdown preparation mode was executed is determined to be outside of the preset current range.

6. The battery management apparatus according to claim 5 , wherein the control unit is further configured to turn off the first switch and the second switch, when the pack current of the first battery pack and the pack current of the second battery pack are within the preset current range during execution of the current diagnosis mode.

7. The battery management apparatus according to claim 5 , wherein the control unit is further configured to maintain the first switch and the second switch in a turn on state when a second notification signal from the power conversion system is received during execution of the current diagnosis mode, when the first switch and the second switch were already turned on at the time point at which the first notification signal was received by the control unit.

8. The battery management apparatus according to claim 1 , wherein the first notification signal indicates that power supply from an electrical grid electrically connected to the power conversion system was interrupted.

9. The battery management apparatus according to claim 4 , wherein the second notification signal indicates that power supply from the electrical grid is resumed.

10. An energy storage system, comprising:
the battery management apparatus according to claim 1 ,
wherein the power conversion system is connectable to the battery management apparatus through the first terminal and the second terminal.

11. A battery management method for protecting the battery management apparatus according to claim 1 , the battery management method comprising:
executing the shutdown preparation mode in response to the first notification signal from the power conversion system, while any one of the balancing steps for parallel connection between the first battery pack and the second battery pack is performed;
determining whether the pack current of the first battery pack and the pack current of the second battery pack are within the preset current range in the shutdown preparation mode; and
turning off the first switch and the second switch when the pack current of the first battery pack and the pack current of the second battery pack are determined to be within the preset current range.

12. The battery management apparatus according to claim 1 , wherein the balancing steps further comprise:
when the SOC difference is greater than or equal to the threshold SOC:
transmitting a first command to the power conversion system to control the power conversion system to supply a first constant power between the first terminal and the second terminal; and
repeating the determining whether the SOC difference between the first battery pack and the second battery pack is less than the threshold SOC;

when the SOC difference is less than the threshold SOC:
transmitting a second command to the power conversion system to control the power conversion system to supply a second constant power between the first terminal and the second terminal, the second constant power being less than the first constant power;
determining whether the voltage of the first battery pack is lower than the voltage of the second battery pack;
when the voltage of the first battery pack is lower than the voltage of the second battery pack, repeating the transmitting the second command to the power conversion system;
when the voltage of the first battery pack is greater than or equal to the voltage of the second battery pack, determining whether the voltage difference between the first battery pack and the second battery pack is larger than a second threshold voltage; and
when the voltagee difference is less than or equal to the second threshold voltage, turning on the second switch such that the first battery pack and the second battery pack are connected in parallel between the first terminal and the second terminal.

13. The battery management apparatus according to claim 12 , wherein the balancing steps further comprise, when the voltage difference is larger than the second threshold voltage:
transmitting a third command to the power conversion system to control the power conversion system to stop supplying the second constant power;
determining whether a stabilization period has passed from a time point at which the third command w

Assignees

• Lg Chemical Ltd

Inventors

• Park Mi-So

Classifications

• H02J7/52 Primary

  for charge balancing, e.g. equalisation of charge between batteries · CPC title

• H02J7/60 Primary

  including safety or protection arrangements · CPC title

• H01M10/482

  for several batteries or cells simultaneously or sequentially · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title

• H01M10/4207

  for several batteries or cells simultaneously or sequentially · CPC title