Methods and apparatus for detecting electrical leakage in a vehicle

1. A vehicle comprising:

a battery pack;

an electric motor;

a contactor configured to electrically connect the battery pack and motor;

control circuitry for the contactor including a leak voltage detection sensor; and

a controller programed to output a leakage resistance between the battery pack and a chassis of the vehicle based on a leak voltage detected by the sensor and corresponding to a leak current that flows through the contactor.

2. The vehicle of claim 1 , wherein the controller is further programed to output an alert if the leakage resistance is less than a threshold value.

3. The vehicle of claim 1 , wherein the sensor is associated with a positive terminal of the battery pack.

4. The vehicle of claim 1 , wherein the sensor is associated with a negative terminal of the battery pack.

5. The vehicle of claim 1 , wherein the controller is further programmed to filter data from the leak voltage detection sensor to reduce noise associated therewith.

6. A leakage path detection circuit comprising:

a first circuit configured to detect a battery voltage of a traction battery in response to closing of a contactor circuit configured to electrically connect the traction battery and a motor, the first circuit including

an input terminal electrically connected with a first terminal of the traction battery, and

a grounded output terminal electrically connected with a second terminal of the traction battery having a polarity opposite the first terminal;

a second circuit configured to detect a leak voltage associated with the traction battery and corresponding to a leak current that flows through the contactor circuit in response to the closing of the contactor circuit, the second circuit including

an input terminal electrically connected with a contactor of the contactor circuit, and

a grounded output terminal; and

at least one controller configured to output a leakage resistance between the traction battery and a vehicle chassis based on the battery voltage and the leak voltage.

7. The leakage path detection circuit of claim 6 , wherein the second circuit is associated with the first terminal of the traction battery and wherein the first terminal has a positive polarity.

8. The leakage path detection circuit of claim 6 , wherein the second circuit is associated with the first terminal of the traction battery and wherein the first terminal has a negative polarity.

9. The leakage path detection circuit of claim 6 , wherein the at least one controller is further configured to apply a filter to the leak voltage and battery voltage to reduce noise associated therewith.

10. The leakage path detection circuit of claim 6 , wherein the at least one controller is further programed to output an alert message if the leakage resistance is less than a threshold value.

11. A method for detecting battery leakage in a vehicle comprising:

in response to closing of a contactor configured to electrically connect a traction battery to a motor, outputting a resistance of a leakage path between the traction battery and a chassis of the vehicle based on a leakage current that flows through the contactor and to the chassis.

12. The method of claim 11 , wherein the leakage path is defined between a positive terminal of the traction battery and the chassis.

13. The method of claim 11 , wherein the leakage path is defined between a negative terminal of the traction battery and the chassis.

14. The method of claim 11 , wherein the leakage path is defined between a positive terminal of the traction battery and the chassis, and a negative terminal of the traction battery and the chassis.

15. The method of claim 11 , further comprising in response to the resistance being less than a predefined threshold value, outputting an alert message.