Load access detection method, switch circuit, and battery management system

Patent metadata

Field	Value
Publication number	US-12009682-B2
Application number	US-202117479505-A
Country	US
Kind code	B2
Filing date	Sep 20, 2021
Priority date	Apr 9, 2020
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A load access detection method, a switch circuit, and a battery management system, relating to the field of circuit technology. The load access detection method includes: detecting a voltage at a first detection point; detecting a voltage at a second detection point; if a voltage difference between the voltage at the first detection point and the voltage at the second detection point is less than or equal to a preset voltage threshold, controlling a switch circuit to enter a pre-charging mode, and pre-charging a load capacitor in the load circuit through the battery pack, where a charging current of the switch circuit in the pre-charging mode is less than a charging current of the switch circuit in a charging mode.

First claim

What is claimed is:

1. A load access detection method, comprising:
detecting a voltage at a first detection point, wherein the first detection point is electrically connected to a positive electrode of a battery group in a battery pack through a bridging resistor;
detecting a voltage at a second detection point, wherein the second detection point is short-circuited with the first detection point when the battery pack is connected to a load circuit; and
under a voltage difference between the voltage at the first detection point and the voltage at the second detection point being less than or equal to a preset voltage threshold condition, controlling a switch circuit to enter a pre-charging mode, and pre-charging a load capacitor in the load circuit through the battery pack, wherein a charging current of the switch circuit in the pre-charging mode is less than a charging current of the switch circuit in a charging mode.

2. The load access detection method according to claim 1 , wherein the under a voltage difference between the voltage at the first detection point and the voltage at the second detection point being less than or equal to a preset voltage threshold condition, controlling a switch circuit to enter a pre-charging mode, and pre-charging a load capacitor in the load circuit through the battery pack comprises:
under the voltage difference between the voltage at the first detection point and the voltage at the second detection point being less than or equal to the preset voltage threshold within a first preset period condition, controlling the switch circuit to enter the pre-charging mode, and pre-charging the load capacitor in the load circuit through the battery pack.

3. The load access detection method according to claim 2 , wherein the switch circuit comprises a first switch, a second switch, and a third switch, and the method comprises:
turning off the second switch, turning on a charging direction of the first switch, and turning on a charging direction of the third switch, so as to form the charging mode of the switch circuit; and
turning off the first switch, turning on a charging direction of the second switch, and turning on the charging direction of the third switch, so as to form the pre-charging mode of the switch circuit; wherein
the first switch is connected in parallel with the second switch; the first switch is connected in series with the third switch; and the second switch is connected in series with the third switch through at least one resistor.

4. The load access detection method according to claim 1 , wherein the switch circuit comprises a first switch, a second switch, and a third switch, and the method comprises:
turning off the second switch, turning on a charging direction of the first switch, and turning on a charging direction of the third switch, so as to form the charging mode of the switch circuit; and
turning off the first switch, turning on a charging direction of the second switch, and turning on the charging direction of the third switch, so as to form the pre-charging mode of the switch circuit; wherein
the first switch is connected in parallel with the second switch; the first switch is connected in series with the third switch; and the second switch is connected in series with the third switch through at least one resistor.

5. The load access detection method according to claim 1 , wherein the controlling a switch circuit to enter a pre-charging mode, and pre-charging a load capacitor in the load circuit through the battery pack comprises:
controlling the switch circuit to maintain the pre-charging mode within a second preset period, and pre-charging the load capacitor through the battery pack.

6. The load access detection method according to claim 1 , further comprising:
determining that an access fault occurs under the voltage difference between the voltage at the first detection point and the voltage at the second detection point being greater than the voltage threshold condition.

7. A battery management system, comprising:
a detection unit, configured to detect a voltage at a first detection point, wherein the first detection point is electrically connected to a positive electrode of a battery group in a battery pack through a bridging resistor;
the detection unit is further configured to detect a voltage at a second detection point, wherein the second detection point is short-circuited with the first detection point when the battery pack is connected to a load circuit; and
a processing unit, configured to control a switch circuit to enter a pre-charging mode, and pre-charge a load capacitor in the load circuit through the battery pack when a voltage difference between the voltage at the first detection point and the voltage at the second detection point is less than or equal to a preset voltage threshold, wherein a charging current of the switch circuit in the pre-charging mode is less than a charging current of the switch circuit in a charging mode.

8. The battery management system according to claim 7 , wherein the processing unit is configured to control the switch circuit to enter the pre-charging mode, and pre-charge the load capacitor in the load circuit through the battery pack when the voltage difference between the voltage at the first detection point and the voltage at the second detection point is less than or equal to the preset voltage threshold within a first preset period.

9. The battery management system according to claim 8 , wherein the switch circuit comprises a first switch, a second switch, and a third switch, wherein the first switch is connected in parallel with the second switch; the first switch is connected in series with the third switch; and the second switch is connected in series with the third switch through at least one resistor;
the processing unit is specifically configured to: turn off the first switch, turn on a charging direction of the second switch, and turn on a charging direction of the third switch, so as to form the pre-charging mode of the switch circuit; and
the processing unit is specifically configured to: turn off the second switch, turn on a charging direction of the first switch, and turn on the charging direction of the third switch, so as to form the charging mode of the switch circuit.

10. The battery management system according to claim 7 , wherein the switch circuit comprises a first switch, a second switch, and a third switch, wherein the first switch is connected in parallel with the second switch; the first switch is connected in series with the third switch; and the second switch is connected in series with the third switch through at least one resistor;
the processing unit is specifically configured to: turn off the first switch, turn on a charging direction of the second switch, and turn on a charging direction of the third switch, so as to form the pre-charging mode of the switch circuit; and
the processing unit is specifically configured to: turn off the second switch, turn on a charging direction of the first switch, and turn on the charging direction of the third switch, so as to form the charging mode of the switch circuit.

11. The battery management system according to claim 7 , wherein the processing unit is configured to control the switch circuit to maintain the pre-charging mode within a second preset period, and pre-charge the load capacitor through the battery pack.

12. The battery management system according to claim 7 , wherein the processing unit is further configured to determine that an access fault occurs when the voltage difference between the voltage at the first detection point and the voltage at the second detection point is greate

Assignees

• Contemporary Amperex Technology Co Ltd

Inventors

• Zhang Xu
• Ma Hang
• Wang Xingchang

Classifications

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/80 Primary

  including monitoring or indicating arrangements · CPC title

• H02J7/855

  with circuits adapted for supplying loads from the battery · CPC title

• H02J7/62

  against overcurrent · CPC title

• H02J7/345

  using capacitors as storage or buffering devices · CPC title