Systems and methods for disengaging a battery

1. A system for disengaging a battery string of a vehicle, comprising:

one or more contactors between the battery string and a direct-current (DC) bus of the vehicle;

at least one transistor connected to the one or more contactors in series;

monitoring circuitry configured to detect a voltage across the transistor after the transistor is switched on; and

a controller configured to:

switch off the transistor after the detected voltage reaches a first voltage level; and

open the one or more contactors.

2. A system for engaging and disengaging a battery string of a vehicle, comprising:

one or more contactors between the battery string and a direct-current (DC) bus of the vehicle;

at least one transistor connected to the one or more contactors in series; and

a controller configured to:

switch off the transistor and open the one or more contactors; and

switch on the transistor and close the one or more contactors after the transistor is switched on.

3. A method for disengaging a battery string of a vehicle, comprising:

detecting, by monitoring circuitry, a voltage across at least one transistor between the battery string and a direct-current (DC) bus of the vehicle after the transistor is switched on, the transistor being connected with one or more contactors in series;

switching off, by the controller, the transistor after the detected voltage reaches a first voltage level; and

opening, by the controller, the one or more contactors between the battery string and the DC bus.

4. A method for engaging and disengaging a battery string of a vehicle, comprising:

switching off, by a controller, at least one transistor between the battery string and the DC bus;

opening, by the controller, one or more contactors between the battery string and the DC bus;

switching on, by the controller, the transistor; and

closing, by the controller, the one or more contactors after the transistor is switched on,

wherein the transistor and the one or more contactors are connected in series.

5. A method for disengaging one of a plurality of battery strings from a direct-current (DC) bus of a vehicle, comprising:

increasing, by a controller, an impedance of a connection between the battery string and the DC bus, wherein increasing the impedance of the connection includes:

operating at least one transistor between the battery string and the DC bus in a linear region to increase an impedance of the transistor;

detecting, by monitoring circuitry, whether a current flowing through the battery string reaches a first current level; and

opening, by the controller, one or more contactors between the battery string and the DC bus after the current flowing through the battery string reaches the first current level.

6. A method for disengaging one of a plurality of battery strings from a direct-current (DC) bus of a vehicle, comprising:

increasing, by a controller, an impedance of a connection between the battery string and the DC bus; detecting, by the monitoring circuitry, whether a current flowing through the battery string reaches a first current level;

opening, by the controller, the one or more contactors between the battery string and the DC bus after the current flowing through the battery string reaches the first current level;

monitoring, by the monitoring circuitry, a voltage across the impedance; and

opening, by the controller, the one or more contactors after the voltage reaches a first level.