METHOD FOR DETECTING DIELECTRIC FLUID CONTAMINATION IN A COOLING CIRCUIT OF A BATTERY TANK IN AN ELECTRIC OR HYBRID MOTOR VEHICLE

Abstract

The invention relates to a method for detecting contamination of a dielectric fluid in a cooling circuit of a battery tray in an electric or hybrid motor vehicle, said dielectric fluid being configured to foam when contaminated, said vehicle comprising a warning means, characterized in that said method comprises a step of measuring the conductivity (E1) of the dielectric fluid by the conductivity sensor; a step of measuring the level (E2) of the dielectric fluid in said battery tray by the level sensor, said level sensor being configured to malfunction when said dielectric fluid foams; and a step of issuing an alert (E3) by the warning means when the conductivity is below a predetermined threshold and when the level sensor malfunctions. Figure 1

Description

Title of the invention: METHOD FOR DETECTING CONTAMINATION OF A DIELECTRIC FLUID IN A COOLING CIRCUIT OF A BATTERY TANK OF AN ELECTRIC OR HYBRID MOTOR VEHICLE

[0001] The invention relates to means for detecting contamination of a dielectric fluid.

[0002] Prior art patent application FR3105597 is known, describing a thermal regulation device for an electrical or electronic component and a method for operating said device. The device comprises a housing containing the electrical or electronic component whose temperature is to be regulated by a dielectric fluid. The electrical or electronic component includes a reservoir for collecting the dielectric fluid. In addition, said device includes a conductivity sensor whose role is to provide information on the quality of the dielectric fluid. However, a drawback remains. Contamination of a dielectric fluid does not necessarily significantly impact its conductivity. Thus, when a conductivity sensor is used to determine whether a fluid is contaminated or not, it is not always capable of detecting potential contamination.

[0003] The objective of the present invention is to overcome these drawbacks and to effectively detect contamination of a dielectric fluid.

[0004] To achieve this objective, the invention proposes a method for detecting contamination of a dielectric fluid in a cooling circuit of a battery tray of an electric or hybrid motor vehicle, said cooling circuit comprising a dielectric fluid conductivity sensor, said battery tray comprising a level sensor, said dielectric fluid being configured to exhibit foaming when said dielectric fluid is contaminated, said vehicle comprising a warning means, notable in that said method comprises the following steps: - a step of measuring the conductivity of the dielectric fluid by the conductivity sensor; - a step of measuring the level of dielectric fluid in said battery tray by the level sensor, said level sensor is configured to present a fault when said dielectric fluid contains foam; - a step of issuing an alert by means of a warning when the conductivity is below a predetermined threshold and when the level sensor has a fault.

[0005] Thanks to the invention, it is possible to detect potential contamination of the dielectric fluid and to warn the driver so that he can carry out its control quickly.

[0006] Preferably, said level sensor is an ultrasonic sensor.

[0007] An ultrasonic sensor is effective for detecting a defect in the dielectric fluid.

[0008] Advantageously, said warning means includes a visual warning device.

[0009] Advantageously, said warning means includes an audible warning device.

[0010] This allows the driver to be warned effectively so that he can plan a check of the dielectric fluid in the battery tray of his vehicle.

[0011] The invention also relates to a battery tray configured to implement said method of detecting contamination of a dielectric fluid in a cooling circuit of a battery tray of an electric or hybrid motor vehicle previously described.

[0012] In addition, the invention relates to an electric or hybrid motor vehicle comprising a battery tray as previously described.

[0013] The invention will be further detailed by the description of a non-limiting embodiment, and on the basis of the attached figure illustrating the invention, in which [Fig.1] schematically illustrates, in the form of a logic diagram, a method for detecting contamination of a dielectric fluid in a cooling circuit of a battery tray of an electric or hybrid motor vehicle according to an embodiment of the invention.

[0014] A method for detecting contamination of a dielectric fluid in the cooling circuit of a battery tray in an electric or hybrid vehicle is schematically illustrated in Figure 1 in the form of a flowchart. The dielectric fluid is in a liquid state. The cooling circuit includes a dielectric fluid conductivity sensor. The conductivity sensor is a device that measures a solution's ability to conduct an electric current. The battery tray includes a level sensor. The dielectric fluid is present in the battery tray. Its level must remain substantially constant to allow optimal operation of the battery cooling circuit. Therefore, the dielectric fluid level is regularly checked using a level sensor.During its service life, the dielectric fluid can become contaminated, particularly in the presence of a material incompatible with said dielectric fluid. When the dielectric fluid is contaminated, it forms a foam on its surface. In this case, it is necessary to drain and replace the dielectric fluid. The invention proposes a method for detecting such contamination of the dielectric fluid without adding any extra components. The vehicle also includes a configured warning system. to issue an alert when contamination of the dielectric fluid is detected. During a conductivity measurement step E1, the conductivity of the dielectric fluid is measured by the conductivity sensor. During a level measurement step E2, the level of the electrical fluid in the battery tray is measured by the level sensor. The level sensor is configured to report a fault when the dielectric fluid contains foam. Preferably, the level sensor is an ultrasonic sensor. The ultrasonic sensor comprises a transmitter and a receiver. In this case, an ultrasonic sound wave is emitted at the speed of sound by the transmitter of the ultrasonic sensor at a predetermined first time. The wave is then reflected by the surface of the dielectric fluid back to the receiver of the ultrasonic sensor at a predetermined second time.The distance between the ultrasonic sensor and the surface of said dielectric fluid is then determined by a controller using the following mathematical formula: . _ vta-rû with being the distance between the ultrasonic sensor and the surface of said fluid dielectric; v being the speed of sound; t1 being the first determined time and t2 being the second determined time. In this way, it is possible to measure and monitor the evolution of the dielectric fluid level in the battery tray. When the surface of the dielectric fluid is covered with foam, the ultrasonic sound wave cannot be reflected. The receiver therefore receives no signal. It is then impossible to determine the dielectric fluid level in the battery tray. During an E3 alert emission step, the vehicle warning system issues an alert when the conductivity is below a predetermined threshold and when the level sensor is faulty. The warning system preferably includes a visual and / or audible warning. For example, it could be an indicator light intended to illuminate when the conductivity is below the predetermined threshold and when the level sensor is faulty.

[0015] In addition, the invention relates to a battery tray configured to implement said method of detecting contamination of a dielectric fluid in a cooling circuit of a battery tray of an electric or hybrid motor vehicle previously described, and to an electric or hybrid motor vehicle comprising such a battery tray.

Claims

Demands

1. A method for detecting contamination of a dielectric fluid in a cooling circuit of a battery tray of an electric or hybrid motor vehicle, said cooling circuit comprising a dielectric fluid conductivity sensor, said battery tray comprising a level sensor, said dielectric fluid being configured to exhibit foam when said dielectric fluid is contaminated, said vehicle comprising a warning means, characterized in that said method comprises the following steps: - a step of measuring the conductivity (E1) of the dielectric fluid by the conductivity sensor; - a step of measuring the level (E2) of dielectric fluid in said battery tray by the level sensor, said level sensor being configured to exhibit a fault when said dielectric fluid exhibits foam;- a step of issuing an alert (E3) by means of a warning when the conductivity is below a predetermined threshold and when the level sensor has a fault.;

2. Method according to claim 1 characterized in that said level sensor is an ultrasonic sensor.

3. Method according to claim 1 or 2 characterized in that said warning means comprises a visual warning device.

4. A method according to any one of claims 1 to 3 characterized in that said warning means comprises an audible warning device.

5. Battery tray configured to implement said method of detecting contamination of a dielectric fluid in a cooling circuit of a battery tray of an electric or hybrid motor vehicle according to any one of claims 1 to 4.

6. Electric or hybrid motor vehicle comprising a battery tray according to claim 5.