ENHANCED CONDUCTIVE FLUID SENSOR FOR HV LIQUID COOLED BATTERY PACKS

• US 20140015511A1
• Filed: 07/10/2012
• Published: 01/16/2014
• Est. Priority Date: 07/10/2012
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Matthe, Roland, Namou, Andrew J.
• Granted Patent: US 9,853,330 B2
• Time in Patent Office: Days
• US Class Current: 324/71.1
• CPC Class Codes: G01M 3/165 by means of cables or similar elongated devices, e.g. tapes
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/633 characterised by algorithms, flow charts, software details or the like
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A sensor for detecting leaked cooling fluid in a battery pack or container. The sensor is part of a sensor wire, where one end of the wire is electrically coupled to the positive terminal or the negative terminal of the battery pack and the other end of the wire is positioned at a location where the leaked cooling fluid may accumulate. A fault isolation detection circuit monitors a voltage output from the sensor and determines that there is a cooling fluid leak if the measured voltage potential is greater than a predetermined voltage threshold.

Claims

1. A method for detecting a cooling fluid leak from a liquid cooled battery pack, said battery pack including a positive terminal and a negative terminal, said method comprising:

electrically coupling a first end of a sensor wire to one of the positive terminal or the negative terminal of the battery pack;

positioning a second end of the sensor wire at a location where leaked cooling fluid may accumulate;

measuring a voltage output from the sensor wire; and

determining that there is a cooling fluid leak if the measured voltage output is greater than a predetermined voltage threshold.

2. The method according to claim 1 wherein the sensor wire includes a resistor and wherein measuring the voltage output includes measuring the voltage output across the resistor.

3. The method according to claim 2 wherein the sensor wire includes a diode electrically coupled in series with the resistor for preventing electrical current from traveling into the battery pack terminal.

4. The method according to claim 1 wherein positioning the second end of the sensor wire includes positioning the second end of the sensor wire relatively close to a support tray on which the battery pack is mounted.

5. The method according to claim 4 wherein a distance between the second end of the sensor wire and the support tray is adjustable.

6. The method according to claim 1 wherein measuring the voltage output includes measuring the voltage output using a voltage isolation circuit.

7. The method according to claim 6 wherein the voltage isolation circuit monitors a voltage balance between the positive terminal and the negative terminal of the battery pack.

8. The method according to claim 1 wherein measuring a voltage output of the sensor wire includes providing an electrical connection between the battery pack terminal and a ground potential by a conductive path from the first end of the sensor wire through the leaked cooling fluid.

9. The method according to claim 1 wherein the battery pack is a high voltage battery pack on an electric vehicle.

10. A method for detecting a cooling fluid leak from a liquid cooled battery pack on an electric vehicle, said battery pack including a positive terminal and a negative terminal, said method comprising:

providing a sensor wire including a sensor resistor, said sensor wire having a first end and a second end;

electrically coupling the first end of the sensor wire to either the positive terminal or the negative terminal of the battery pack;

positioning the second end of the sensor wire at a location where leaked cooling fluid may accumulate;

providing a fault isolation circuit;

monitoring a voltage output across the sensor resistor using the fault isolation circuit; and

determining that there is cooling fluid leak if the voltage output of the sensor resistor exceeds a voltage threshold.

11. The method according to claim 10 wherein the sensor wire includes a diode electrically coupled in series with the resistor for preventing electrical current from traveling into the battery pack terminal.

12. The method according to claim 10 wherein the fault isolation circuit monitors a voltage balance between the positive terminal and the negative terminal of the battery pack.

13. The method according to claim 10 wherein measuring a voltage output of the sensor wire includes providing an electrical connection between the battery pack terminal and a ground potential by a conductive path from the first end of the sensor wire through the leaked cooling fluid.

14. A battery circuit electrically coupled to a battery pack, said battery pack including a positive terminal and a negative terminal, said battery circuit comprising:

a leak detection circuit for detecting a cooling fluid leak from a cooling fluid channel that cools the battery pack, said leak detection circuit including a resistor provider within a sensor wire, said sensor wire having a first end electrically coupled to the positive terminal or the negative terminal of the battery pack and a second end positioned at a location where the leaked cooling fluid may accumulate; and

a fault isolation circuit electrically coupled to the positive terminal and the negative terminal of the battery pack, said fault isolation circuit monitoring a voltage potential across the resistor and providing a leak detected signal if the second end of the wire is positioned within the leaked cooling fluid and creates an electrical path from the battery pack terminal to ground.

15. The battery circuit according to claim 14 wherein the leak detection circuit includes a diode electrically coupled in series with the resistor for preventing electrical current traveling into the battery pack terminal.

16. The battery circuit according to claim 14 where a distance between the second end of the sensor wire and a component at ground potential is adjustable.

17. The battery circuit according to claim 14 wherein the fault isolation circuit monitors a voltage balance between a positive terminal and a negative terminal of the battery pack.

18. The battery pack according to claim 14 wherein the battery pack is a high voltage battery pack on an electric vehicle.