Smart contactor for battery disconnection unit

1. A switching device comprising:

a first connector and a second connector, the first connector being configured to connect to a first terminal of a battery and the second connector being configured to connect to a first power line of a power system;

a first input and a second input, the first input being configured to receive a first switch control signal from a battery control unit and the second input being configured to receive a second switch control signal from the battery control unit, the first switch control signal and the second switch control signal each selectively commanding one of an open switch state and closed switch state;

an output configured to operably connect to a contactor that is connected between a second terminal of the battery and a second power line of the power system, the contactor being operated via the output;

a switch connected between the first connector and the second connector;

a current sensor configured to measure a current flowing through the switch; and

a controller operatively connected to the current sensor, the switch, the first input, the second input, and the output, the controller being configured to:

operate the switch based on the first switch control signal at the first input;

pass through the second switch control signal from the second input to the output;

operate the switch to open in response to the current flowing through the switch exceeding a predetermined current limit; and

interrupt the pass through of the second switch control signal to the output in response to the current flowing through the switch exceeding the predetermined current limit.

2. The switching device of claim 1 further comprising:

a temperature sensor configured to measure a temperature of the switch; and

the controller being connected to the temperature sensor and further configured to:

operate the switch to open in response to the temperature of the switch exceeding a predetermined temperature limit; and

interrupt the pass through of the second switch control signal to the output in response to the temperature of the switch exceeding the predetermined temperature limit.

3. The switching device of claim 1 , the controller being further configured to:

after operation of the switch to open in response to the current flowing through the switch exceeding a predetermined current limit, resume operation of the switch based on the first switch control signal at the first input in response to a first switch control signal having a logical zero value; and

after operation of the switch to open in response to the current flowing through the switch exceeding a predetermined current limit, resume the pass through of the second switch control signal to the output in response to a first switch control signal having a logical zero value.

4. The switching device of claim 1 , the switch further comprising:

a field-effect transistor.

5. The switching device of claim 4 , the switch further comprising:

at least two field-effect transistors arranged in parallel.

6. The switching device of claim 1 further comprising:

a DC/DC converter connected to the first connector and to the controller, the DC/DC converter being configured to provide power to the controller by converting a DC voltage at the first connector into a DC voltage for the controller.

7. The switching device of claim 1 further comprising:

a driver circuit connected to the switch and to the controller, the driver circuit being configured to:

receive a control signal from the controller; and

operate the switch to open and close based on the received control signal from the controller.

8. The switching device of claim 1 , further comprising:

a housing configured to enclose the switch, the current sensor, and the controller, the first connector and the second connector being arranged on the housing.

9. The switching device of claim 1 , wherein the first connector is configured to connect to a negative terminal of a vehicle battery and the second connector is configured to connect to a negative power line of a vehicle power system.

10. A vehicle battery system comprising:

a battery having a first terminal and a second terminal;

a battery control unit configured to output a first switch control signal and a second switch control signal, the first switch control signal and the second switch control signal each selectively commanding one of an open switch state and closed switch state;

a contactor connected between the first terminal of the battery and a first power line of a vehicle power system; and

a switching device connected between the second terminal of the battery and a second power line of the vehicle power system, the switching device comprising:

a first connector and a second connector, the first connector being connected to the second terminal of the battery and the second connector being connected to the second power line of the vehicle power system;

a first input and a second input, the first input being connected to receive the first switch control signal from the battery control unit and the second input being connected to receive the second switch control signal from the battery control unit;

an output operably connected to operate the contactor;

a switch connected between the first connector and the second connector;

a current sensor configured to measure a current flowing through the switch; and

a controller connected to the current sensor, the switch, the first input, the second input, and the output, the controller being configured to:

operate the switch based on the first switch control signal at the first input;

pass through the second switch control signal from the second input to the output;

operate the switch to open in response to the current flowing through the switch exceeding a predetermined current limit; and

interrupt the pass through of the second switch control signal to the output in response to the current flowing through the switch exceeding the predetermined current limit.

11. The vehicle battery system of claim 10 , the switching device further comprising:

a temperature sensor configured to measure a temperature of the switch; and

the controller being connected to the temperature sensor and further configured to:

operate the switch to open in response to the temperature of the switch exceeding a predetermined temperature limit; and

interrupt the pass through of the second switch control signal to the output in response to the temperature of the switch exceeding the predetermined temperature limit.

12. The vehicle battery system of claim 10 , the controller being further configured to:

after operation of the switch to open in response to the current flowing through the switch exceeding a predetermined current limit, resume operation of the switch based on the first switch control signal at the first input in response to a first switch control signal having a logical zero value; and

after operation of the switch to open in response to the current flowing through the switch exceeding a predetermined current limit, resume the pass through of the second switch control signal to the output in response to a first switch control signal having a logical zero value.

13. The vehicle battery system of claim 10 , the switch further comprising:

a field-effect transistor.

14. The vehicle battery system of claim 13 , the switch further comprising:

at least two field-effect transistors arranged in parallel.

15. The vehicle battery system of claim 10 , the switching device further comprising:

a DC/DC converter connected to the first connector and to the controller, the DC/DC converter being configured to provide power to the controller by converting a DC voltage at the first connector into a DC voltage for the controller.

16. The vehicle battery system of claim 10 , the switching device further comprising:

a driver circuit connected to the switch and to the controller, the driver circuit being configured to:

receive a control signal from the controller; and

operate the switch to open and close based on the received control signal from the controller.

17. The vehicle battery system of claim 10 , the switching device further comprising:

a housing configured to enclose the switch, the current sensor, and the controller, the first connector and the second connector being arranged on the housing.