Passive Detection of Overheating in Electrical Connectors

Abstract

The present invention relates to passive detection of overheating in an electrical connector. An electrical connector includes a detection device (110) for detecting potential overheating, the detection device including a conductive element (160) and an electrically insulating element (170) inserted between the conductive element (160) and a low-voltage line. The conductive element (160) exerts an elastic force on the insulating element (170). For example, the conductive element (160) is a spring. In the case of overheating, the insulating element (170) deforms under the pressure of the conductive element (160) and an electrical connection between two low-voltage lines is achieved. The overheating is detected due to the electrical design of this connection between the low-voltage lines.

Description

Field of the Invention

[0001] The present invention relates to the field of electrical connectors for electric or hybrid motor vehicles. Background Art

[0002] Electrical connectors are used in electric or hybrid motor vehicles, for example to charge a battery from a charging station, to interconnect a set of batteries with an electric motor, a power converter, etc.

[0003] In hybrid and electric motor vehicles, the current transmitted by the cables and connectors of the power supply circuit is relatively high and can reach 600 amperes at current peaks, or even more than 1000 amperes. Such current may cause overheating in the connectors.

[0004] Therefore, it is important to be able to limit the risk of such overheating and / or to disconnect the supply of the electric current transmitted by the connector in case of overheating and / or to provide information that overheating has occurred, in order to prompt an inspection of the circuit in which such overheating has occurred.

[0005] Solutions involving integrating temperature probes in the connectors are known. Temperature probes, such as thermocouples, can be relatively expensive, all the more so since electronic circuits must be used to perform and interpret the measurements at their terminals. Other solutions involve integrating fuses powered by a low voltage current in the connectors. Temperature probes, such as thermal fuses, have a specific shape, which can pose problems in integrating them in the connectors. Moreover, even if the information given by the temperature probe or fuse indicates that overheating has occurred, this does not necessarily prevent the continued use of the connector, which potentially creates a safety problem.

[0006] The present disclosure proposes an alternative to the existing solutions. Summary of the Invention

[0007] To this end, an electrical connector including a housing is proposed. The housing particularly houses at least one first conductive component and at least one second conductive component, where the at least one first conductive component is configured to be integrated in a first low-voltage electrical line, and the at least one second conductive component is configured to be integrated in a second low-voltage electrical line. In an exemplary embodiment, as described in detail below, the first low-voltage electrical line is configured to be electrically linked and connected to an interlock control circuit of a high-voltage circuit (also referred to as "HVIL" or "high-voltage interlock loop"). The interlock control loop or circuit is used in the connector to detect the connection or disconnection of the connector and the mating connector, and to trigger or disconnect the supply of power in the power contacts housed in the connector and the mating connector. The second low-voltage electrical line may include, for example, one or more shielding elements. In this case, the second conductive component may be a shielding element attached to the housing, such as a shielding metal sheet assembled to the housing. The shielding element enables at least partial shielding of electromagnetic waves generated by the flow of high current in the cables and the contacts housed in the connector housing. The shielding element is first electrically connected to the shielding braid of each cable and / or to the shielding sheath surrounding a plurality of cables, and second electrically connected to the shielding of the mating connector and / or the conductive wall on which the connector is mounted.

[0008] Solutions involving the use of low-voltage lines that are already provided for another function (interlock circuit or shield) enable the provision of a function for detecting potential overheating in a power connector without significantly complicating the manufacture and installation of such a connector, as this does not require the addition of specific contacts and / or wires dedicated to such detection.

[0009] The first conductive component may be an electrical contact, an electrical contact blade, a shunt, a spring, or any other element configured to be electrically connected, linked, or integrated into or in the first low-voltage line.

[0010] The electrical connector further includes at least one electrical insulating element and at least one conductive element inserted between the first conductive component and the second conductive component. In other words, the electrical insulating element may be inserted between the conductive element and the first conductive component, or between the conductive element and the second conductive component, or both between the conductive element and the first conductive component on one side and between the conductive element and the second conductive component on the other side. The insulating element is made of a material having a melting temperature less than or equal to the melting temperature of at least one of the materials forming the housing. For example, the insulating element is made of a material having a melting temperature between 125°C and 200°C. The insulating element may also be characterized by a glass transition temperature or any other property considering its ability to deform under the combined action of temperature and mechanical stress.

[0011] Specifically, when the electrical insulation element reaches a given temperature, for example a temperature greater than or equal to its melting temperature, the conductive element exerts an elastic force on the insulation element that is suitable for deforming the electrical insulation element. After this deformation, the conductive element establishes an electrical connection between the first conductive component and the second conductive component. This results in a short circuit between, for example, a first low-voltage line and a second low-voltage line, which can be reflected, for example, by the grounding of the first low-voltage line and the like.

[0012] Therefore, if excessive overheating occurs in the connector, the insulation element softens or even melts at least locally, and the conductive element that exerts pressure on the insulation element deforms the insulation element until an electrical contact is established with the first conductive component on the one hand and with the second conductive component on the other hand, thereby creating an electrical connection between the first conductive component and the second conductive component. This results in a modification of the voltage on the first low-voltage line and / or the second low-voltage line. This modification constitutes a signal that enables the detection of overheating. After this detection, information can be displayed on the vehicle's dashboard to signal that the vehicle should be repaired, and the detection device including the insulation element that has melted can be replaced, and as an alternative or in addition, it is possible to interrupt the current flowing through the conductor.

[0013] In any case, for the modification that occurs between the first low-voltage line and the second low-voltage line in the event of overheating, it can be advantageous to put the connection assembly, or at least the connector or mating connector, out of service. For example, when one of the low-voltage lines is connected to an interlock control circuit, grounding this line causes the circuit not to work, thereby not performing any electrical signal processing operations. In other words, putting the connection assembly, connector, or mating connector out of service in this case is not caused by any calculation or signal processing; it is a direct result of the material event (short circuit or grounding) caused by overheating that leads to the deformation of the electrical insulation element. It should be noted that in the same way that overheating is a dangerous event, overheating is the cause of the deformation of the electrical insulation element, and this dangerous event has the risk of damaging the connector housing made of plastic. In other words, the phenomenon used to detect overheating is the same as the phenomenon that is the cause of the problem that is desired to be avoided. Therefore, this gives a consistent and reliable method for detecting overheating.

[0014] Furthermore, the deformation of the electrical insulation element is an irreversible event, which requires the replacement of all or part of the connection assembly in which the electrical insulation element is placed. This represents an advantage in terms of safety level.

[0015] Therefore, the material of the electrical insulation element is selected according to its melting temperature, which defines the acceptable limit of the connector, mating connector, connection assembly or its components or its adjacent components.

[0016] The connector may also include one and / or the other of the following features, each feature being considered independent of each other or in combination with one or more other features:

[0017] - The first conductive component is configured to be connected to an interlock control circuit of a high-voltage circuit via the first low-voltage line;

[0018] - The second conductive component is a shielding element attached to the housing;

[0019] - The insulating element and the conductive element are integrated together in a passive detection device, and the passive detection device is installed in a recess of the housing;

[0020] - In the absence of overheating, the conductive element is in contact with the conductive component or with the shielding element;

[0021] - The conductive element exerts a force between 1 Newton and 50 Newtons on the electrical insulating element;

[0022] - The conductive element is a helical spring, and the helical spring is compressed between the electrical insulating element on one hand and the first conductive component or the shielding element on the other hand.

[0023] According to another aspect, a connection assembly is proposed, which includes the connector and a mating connector as described above. The mating connector includes a housing that houses signal contacts, and the signal contacts are configured to be integrated in the first low-voltage line. When the connector and the mating connector are coupled, these contacts are connected to the first conductive component.

[0024] According to yet another aspect, a method for detecting overheating in an electrical connection assembly is proposed, in which the deformation of an electrical insulating element made of plastic under stress from a conductive element is used to modify a circuit.

[0025] For example, the method includes an operation of collecting a signal by performing a series of electrical measurements on the first low-voltage line. The method further includes the following operations: monitoring whether the signal collected during the series of electrical measurements performed on the first low-voltage line changes over time after the first low-voltage line is connected to a second low-voltage line, and the connection is the result of the deformation of the electrical insulating element.

[0026] The method may include the following operations, in which the first conductive component is connected to an interlock control circuit of a high-voltage circuit, and a change in the signal occurs after the first conductive component is connected to the shielding element of the connector via the conductive element. Description of the Drawings

[0027] Other features and advantages of the present invention will become apparent by reading the following detailed description and with reference to the drawings. In these drawings:

[0028] Figure 1Schematically shows an exemplary embodiment of a connection assembly including a connector and a mating connector before the connector and the mating connector are coupled;

[0029] Figure 2 Schematically shows the connection assembly shown in Figure 1 after the connector and the mating connector have been coupled;

[0030] Figure 3 Schematically shows the connection assembly shown in Figure 1 after the connector and the mating connector have been coupled and after a passive detection device for detecting overheating has been deformed;

[0031] Figure 4 Schematically shows, from an electrical perspective, the state of a passive detection device for passive overheating detection before overheating;

[0032] Figure 5 Schematically shows, from an electrical perspective, the state of a passive detection device for passive overheating detection after overheating;

[0033] Figure 6 Schematically shows, in a perspective view, an example of an embodiment of a connector equipped with a passive detection device for detecting overheating;

[0034] Figure 7 Schematically shows Figure 6 a cross-sectional view of the connector;

[0035] Figure 8 Schematically shows, in a perspective view, an exemplary embodiment of a passive detection device for detecting overheating, which can be installed in a connector such as Figure 6 the connector;

[0036] Figure 9 Schematically shows, in a front view from its front or coupling face, the details of Figure 6 the connector. Detailed Description

[0037] Figure 1 Schematically shows an example of a connection assembly 1. The connection assembly includes a connector 100, which is configured to be coupled to a mating connector 200 parallel to a coupling direction A.

[0038] The connector 100 is a cable connector. The mating connector 200 is a socket configured to be mounted on a wall 300 and pass through the wall. According to this example, the connector 100 is a female connector and the mating connector 200 is a male connector.

[0039] The connector 100 particularly includes a housing 102, power contacts 104, a conduction member 106, a shielding element such as a shielding cage 108, and a passive detection device 110 for passively detecting potential overheating.

[0040] The housing 102 of the connector 100 is formed by one or more elements made of insulating plastic. The power contacts 104 are received in chambers formed in the housing 102. These are female power contacts that are each electrically connected to a cable 112. In this example, the conduction member 106 is an electrical contact blade having two flexible contact tabs 114 that are electrically connected to each other to form a shunt. The shielding cage 108 is constituted by one or more metal sheets made of a conductive material. The shielding cage 108 is configured to at least partially shield electromagnetic waves generated by the flow of high current through the connection assembly 1. The shielding cage 108 is in electrical contact with each shielding braid of the cable 112 (and / or in electrical contact with a shielding sheath shared by a plurality of cables 112, this configuration not shown).

[0041] The mating connector 200 particularly includes a housing 202, power contacts 204, signal contacts 206, and a shielding element, such as a shielding cage 208.

[0042] The housing 202 of the mating connector 200 is formed by one or more elements made of insulating plastic. The power contacts 204 are received in chambers formed in the housing 202. These are male power contacts that are each electrically connected to a cable 212. Two of the signal contacts 206 are each connected to an interlock control circuit 210 through a wire 214. Thus, the signal contacts 206 and the wire 214 are integrated in a first low-voltage electrical circuit. The interlock control circuit 210 controls the opening and closing of a high-voltage circuit including the power contacts 204 of the mating connector 200.

[0043] The shielding cage 208 is constituted by one or more metal sheets made of a conductive material. The shielding cage 208 is configured to at least partially shield electromagnetic waves generated by the flow of high current through the connection assembly 1. The shielding cage is in electrical contact with each shielding braid of the cable 212 (and / or in electrical contact with a shielding sheath shared by a plurality of cables 112, this configuration not shown). The shielding cage 208 is also in electrical contact with a wall 300 that is itself connected to the ground of the vehicle.

[0044] Thus, the shielding cages 108, 208 are intended to participate in a second low-voltage electrical circuit connected to the ground of the vehicle. Alternatively, the shielding cages 108, 208 are integrated in a low-voltage electrical circuit not connected to the ground of the vehicle.

[0045] When the connector 100 and the mating connector 200 are coupled, the male power contacts 204 and the female power contacts 104 are connected in pairs, and the signal contacts 206 are connected to the conductive member 106, thereby closing the loop of the interlock control circuit 210, and the corresponding shielding cages 108, 208 of the connector 100 and the mating connector 200 are in electrical contact with each other (thereby also potentially enabling the connection of the cages of the connectors to the ground of the vehicle).

[0046] When the connector 100 and the mating connector 200 are coupled, the interlock control circuit 210 controls and triggers the power supply to the power contacts 204 ( Figure 2 ). In the absence of overheating, the detection device 110 electrically insulates the conductive member 106 from the shielding cage 108 of the connector 100. The first low-voltage electrical line and the second low-voltage electrical line are isolated from each other.

[0047] In the case of overheating of the connector 100 and / or the mating connector 200, the detection device 110 deforms and connects the conductive member 106 to the shielding cage 108 of the connector 100 ( Figure 3 ). The interlock control circuit 210 detects a change in the signal measured on the loop of the interlock control circuit 210. For example, before overheating, the interlock control circuit 210 continuously measures the voltage corresponding to the resistance R, where the resistance R represents the resistance of the wire 214, the resistance of the signal contact 206, and the resistance of the conductive member 106, as well as the contact resistance between these various elements. After overheating, the interlock control circuit 210 measures the voltage corresponding to the resistance R', where the resistance R' represents the resistance of one of the wires 214, the resistance of one of the signal contacts 206, the resistance of the conductive member 106 and a part of the detection device 110, as well as the contact resistance between these various elements. The change between R and R' is sufficient to signal a change in the configuration in the detection device 110, which change is caused by overheating in the connection assembly 1. Alternatively, grounding the interlock control circuit renders it inoperative, which may cause the power supply to the power contacts 104, 204 to be disconnected.

[0048] The change in the configuration of the detection device 110 is schematically shown in Figure 4 and Figure 5 . In Figure 4 , before overheating, there is no connection between the loop 216 of the interlock control circuit 210 and the line 116 incorporating the shielding cage 108 (effectively an infinite resistance in the detection device 110) (the first low-voltage electrical line 116 and the second low-voltage electrical line 216 are isolated from each other). In Figure 5 , after overheating, the detection device 110 connects the loop 216 of the interlock control circuit 210 and the line 116 incorporating the shielding cage 108 (the first low-voltage electrical line 116 and the second low-voltage electrical line 216 are connected to each other).

[0049] Reference Figures 6 to 9 ( Figure 1 )A specific exemplary embodiment of the connector 100 is described.

[0050] According to this example, the connector 100 includes an inner housing element 120, an outer housing element 130, two shielding metal sheets 141, 142 forming a shielding cage 108, a conductive member 106, a detection device 110, and a coupling assist device 150.

[0051] The shielding metal sheets 141, 142 are inserted between the inner housing element 120 and the outer housing element 130.

[0052] The detection device 110 includes a conductive element 160 and an electrically insulating element 170( Figure 8 ). The conductive element 160 is a helical spring. The axial force Fx provided by the conductive element 160 is, for example, between 1 Newton and 50 Newtons. The conductive element 160 is mounted in a support 180. In Figure 8 the illustrated exemplary embodiment, the support 180 is integral with the electrically insulating element 170 and is made of a material having a melting temperature between 125 °C and 200 °C. For example, the melting temperature is equal to or close to 180 °C. For example, the polymeric material is polypropylene, polyethylene, or epoxy resin.

[0053] The support 180 and the electrically insulating element 170 form a part having a U-shaped cross-section. One of the branches of the U-shape includes an opening 182 for the conductive element 160 to pass through (see Figure 7 ). The other branch of the U-shape corresponds to the insulating element 170 on which the conductive element 160 is supported and to which the conductive element 160 applies a pressure corresponding to the axial force Fx.

[0054] When the detection device 110 is mounted in the connector 100, the support 180 is surrounded in a recess formed in the inner housing element 120 of the connector 100 such that the conductive element 160 is in electrical contact with the conductive member 106 (and more specifically, with one of its flexible tabs 114) via one of its axial ends, and is insulated from the shielding metal sheet 141 by the insulating element 170 at the other axial end ( Figure 9 ).

[0055] Thus, the electrically insulating element 170 is inserted between the conductive element 160 and the shielding metal sheet 141. The thickness E of the thus inserted electrically insulating element 170 is, for example, between 0.5 millimeters and 2 millimeters. For example, the thickness E is equal to or close to 0.8 millimeters.

[0056] Thus, in the case of overheating, that is to say, if the temperature in the connector becomes, for example, greater than or equal to 180 °C, the insulating element softens and, under the action of the pressure exerted by the conductive element 160 on the electrical insulating element 170, the conductive element 160 passes through the electrical insulating element 170 and establishes electrical contact with the shielding metal sheet 141.

[0057] Other variants of the detection device 110 described above are conceivable. For example, an electrical insulating element 170 similar to the above-described electrical insulating element can be inserted between the conductive element 160 and the conductive part 106. As an alternative, the electrical insulating element 170 is inserted between the conductive elements 160 on one side and between the conductive element 160 and the shielding cage 108 on the other side.

[0058] Likewise, the shielding element can be formed of other materials than metal sheets (for example, a housing element on which a conductive layer is deposited).

[0059] Likewise, the conductive element can be an element other than a spring (for example, a part that expands under the action of heat).

[0060] The detection device can be mounted in the mating connector 200 instead of in the connector 100, or in both the connector 100 and the mating connector 200.

[0061] The connecting device 1 can be designed to connect a single cable or more than two cables, rather than the connecting device 1 enabling the connection of a pair of two power cables 112, 212.

[0062] The connector and the mating connector do not necessarily have a shield and / or are not necessarily connected to an interlock control circuit. In this case, the low-voltage line can be a dedicated line or a line configured to transmit signals.

Claims

1. A power connector (100) for an electric or hybrid motor vehicle and configured to be coupled to a mating connector (200), the power connector (100) comprising a housing (102) that houses power contacts (104), at least one first conductive component (106) configured to be integrated in a first low-voltage electrical circuit, and at least one second conductive component (108) configured to be integrated in a second low-voltage electrical circuit, the first low-voltage electrical circuit being configured to be electrically connected to an interlock control circuit of a high-voltage circuit, the interlock control circuit controlling the opening and closing of the high-voltage circuit including the power contacts (104) of the power connector (100) and the power contacts (204) of the mating connector (200). Characterized in that, the power connector further comprises at least one electrical insulation element (170) and at least one conductive element (160) inserted between the first conductive component (106) and the second conductive component (108). The electrical insulation element (170) is made of a material having a melting temperature less than or equal to the melting temperature of at least one of the materials forming the housing (102). The conductive element (160) exerts an elastic force on the electrical insulation element (170), the elastic force being adapted to deform the electrical insulation element (170) when the temperature of the electrical insulation element (170) is greater than or equal to its melting temperature and establish an electrical connection between the first conductive component (106) and the second conductive component (108), and the first conductive component (106) is configured to be connected to the interlock control circuit (210) of the high-voltage circuit via the first low-voltage electrical circuit.

2. The power connector (100) according to claim 1, wherein, the second conductive component is a shielding element (108) attached to the housing (102).

3. The power connector (100) according to claim 2, wherein, the electrical insulation element (170) is inserted between the conductive element (160) and the shielding element (108).

4. The power connector (100) according to claim 1 or 2, wherein, the electrical insulation element (170) and the conductive element (160) are integrated together in a passive detection device (110), the passive detection device being mounted in a recess in the housing (102).

5. The power connector (100) according to claim 1 or 2, wherein, the conductive element (160) exerts a force between 1 Newton and 50 Newtons on the electrical insulation element (170).

6. The power connector (100) according to claim 1 or 2, wherein, the conductive element (160) is a helical spring compressed between at least one of the first conductive component (106) and the second conductive component (108) and the electrical insulation element (170).

7. A connection assembly (1), said connection assembly comprising a mating connector (200) and a power connector (100) according to any one of the preceding claims, said mating connector comprising a housing (202), said housing accommodating signal contacts (206), said signal contacts being configured to be integrated in said first low-voltage electrical line, and when said power connector (100) and said mating connector (200) are coupled, these signal contacts (206) are connected to said first conductive member (106).

8. A method for detecting overheating in a connection assembly (1) according to claim 7, wherein, the deformation of an electrically insulating element (170) made of plastic under stress from a conductive element (160) is used to change a circuit.

9. The method according to claim 8, said method comprising the operation of collecting signals by performing a series of electrical measurements on a first low-voltage line, said method further comprising the operation of monitoring whether the signals collected during a series of electrical measurements performed on said first low-voltage line change over time after said first low-voltage line is connected to a second low-voltage line, said connection of said first low-voltage line to said second low-voltage line being the result of said deformation of said electrically insulating element (170).

10. The method according to claim 9, said method comprising the operation of connecting a first conductive member (106) to an interlock control circuit (210) of a high-voltage circuit and said change in said signal occurring after said first conductive member (106) is connected to a shielding element (108) of said power connector (100) via said conductive element (160).

Images