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

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.

A switch circuit, comprising 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 switch circuit is configured to enter a pre-charging mode according to control of the battery management system;
• and
• the switch circuit is further configured to pre-charge 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.