Patent Description:
In electromobility, HV plug-in connectors with large conducting cross-sections are needed for propulsion and for charging the HV battery. In order to shorten the charging times, temperature sensors are used in the HV system. In HV plug-in connectors too, temperature sensors are increasingly needed. The more accurate the temperature measurement in the plug-in connector, the better can the HV system adjust the charging parameters, and thus shorten the charging times. In conventional HV plug-in connectors it is difficult to position the temperature sensor in the vicinity of the contact point (in the following also referred to as 'hotspot'). Often there only remains the option of installing the temperature-measurement sensor in the crimping region or at the current rail (remote from the hotspot).

<FIG> illustrate a known HV plug-in connector arrangement. <FIG> shows a schematic sectional view of a plug-in connector <NUM> in the plugged-in state. The plug-in connector <NUM> comprises a plug-in connector element <NUM> and a mating plug-in connector element <NUM>. As shown, the plug-in connector element <NUM> is a socket element with an electrically conductive spring-loaded contact element <NUM> and the mating plug-in connector element <NUM> is a plug-in element with an electrically conductive blade contact <NUM>.

<FIG> shows the plug-in connector element <NUM> in a perspective view. <FIG> shows the mating plug-in connector element <NUM> in a perspective view. In addition, <FIG> illustrate the functionality of the contact protection in both connecting elements <NUM>, <NUM>, in that test probes <NUM> (known as test fingers), which are not allowed to touch the electrically conductive parts, are in each case shown schematically.

The electrical contact between the plug-in connector element <NUM> and the mating plug-in connector element <NUM> takes place in contact region <NUM>, in which the electrically conductive spring-loaded contact element <NUM> presses on the blade contact <NUM>. In order to monitor the temperature of the contact region <NUM>, a temperature sensor 212A, 212B should be mounted as close as possible to the contact region <NUM>. In the known arrangement shown, however, due to the spatial conditions, this is possible only in the connecting region of blade contact <NUM> (temperature sensor 212A) and/or in the crimping region of the socket element (temperature sensor 212B). For this reason, however, the distance to the actual generation zone of a potential temperature increase is too great to be able to react quickly enough to overheating. The consequence is that e.g. batteries have to be charged with lower charging currents over longer times.

Document <CIT> relates to a load contact module for a charging plug-in connection, comprising: a load contact, which is designed to electromechanically contact a load contact to be inserted and/or slid on; a mounting portion, which is designed to connect the load contact module to a support of a charging plug and/or of a charging socket; and a temperature sensor for the temperature monitoring of a charging process, characterized in that the temperature sensor has a distance from the mounting portion.

Document <CIT> relates to an electric connector that includes a male connector and a female connector, the male connector including a cylindrical main portion and a male contact terminal is formed at the main portion, the female connector including a hole into which the main portion is fit, the male connector including a guide shaft axially extending in a direction in which the male connector is fit into the female connector, the female connector including a guide hole for allowing the guide shaft to be inserted thereinto to guide the guide shaft in the direction.

There exists, therefore a need for a plug-in connector element that overcomes the drawbacks of the known solutions, such that the enclosed plug-in connections are safe and reliable in operation, but nevertheless can be fabricated cost-effectively.

This object is solved by the subject matter of the independent patent claims. Advantageous embodiments of the present invention are the subject matter of the dependent patent claims.

The present invention is based on the idea of embedding at least one temperature sensor in an HV plug-in connector not in a housing element but in a contact protection element or arranging it at the surface of the contact protection element. In this way the temperature sensor can be arranged directly in the electrical contact zone between the plug-in connector element and the mating plug-in connector element and be connected thermally over the shortest possible distance with the region in which potential overheating arises.

In particular, a plug-in connector element for detachable electrical contacting of a mating plug-in connector element comprises at least one electrically conductive contact element, one housing, and one contact protection element, which is so disposed that between the housing and the contact protection element, access to the electrically conductive contact element is prevented for objects with a diameter above a defined value. At least one temperature sensor, which at least in part is accommodated within the contact protection element, can be operated in order to measure a temperature of the electrically conductive contact element.

This arrangement has the advantage that the temperature sensor can be situated installation-space-neutrally and flexibly even in the immediate vicinity of the hotspot. The sensor is arranged in the contact protection element at the optimal position as regards contact layout. The necessary contact pressure of the sensor on the measurement surface is produced, depending on the mounting position, either by the plugging-in process or when assembling the contact protection. The connecting line of the sensor too, can be reliably installed and routed away in the contact protection element. With this solution, temperature measurement in the HV plug-in connector becomes more accurate and more flexible.

At this point let it be noted that of course not only one single temperature sensor but also a large number of temperature sensors can be arranged in and/or at the contact protection element. Furthermore, temperature sensors with more than only one sensitive region can also be deployed.

In order to be able to monitor the temperature in real time as far as possible, the at least one temperature sensor is so arranged according to an advantageous embodiment that it measures the temperature of the electrically conductive contact element in a contact region in which the electrically conductive contact element is electrically contactable through an electrically conductive mating contact element of the mating plug-in connector element.

According to an advantageous aspect, the housing has an essentially cylindrical inner surface at which the electrically conductive contact element is disposed, wherein the electrically conductive contact element grips the contact protection element around at least in part. In this way an especially compact construction can be realized.

Here the contact protection element can have a columnar structure and the temperature sensor is arranged at an external wall of the contact protection element. Then the temperature sensor comes into especially tight heat-conducting contact with the contact region, in which the electrically conductive contact element is electrically contactable through an electrically conductive mating contact element of the mating plug-in connector element, and the achievable response times to a temperature increase are especially short.

Alternatively or additionally, it can also be provided that the contact protection element has a columnar structure and the temperature sensor is arranged on the inside of the contact protection element. Here the temperature sensor is especially well protected against mechanical stressing during the plugging-in process.

According to a further advantageous embodiment of the present invention, the electrically conductive contact element comprises a cylindrical main body and a spring element (also referred to as a spring contact) for spring-loaded contacting of the electrically conductive mating contact element. Thus the necessary contact pressure between the electrical contact elements to one another and to the temperature sensor can be produced in a simple way when connecting together the plug-in connector with the mating plug-in connector.

In particular, the spring element can have an essentially ring-like shape and have a large number of bilaterally fastened flexible tongues, which at their center are bent radially inward in order to contact the electrically conductive mating contact element. Thereby a uniform and firm contact pressure is ensured which guarantees reliable electrical and mechanical contact even in the presence of vibrations and wide temperature ranges.

In order to protect the connecting line especially, it can be provided that the electrical connecting line of the at least one temperature sensor is routed through the contact protection element.

According to an advantageous further development of the present invention, the contact protection element is implemented as an electrically insulating, electrically insulating synthetic part pressed into the electrically conductive contact element. Thereby the temperature sensor can be for example directly so overmolded, that its housing simultaneously forms the contact protection element. This reduces the manufacturing costs and ensures a compact construction.

The present invention further concerns a plug-in connector with a plug-in connector element according to the present invention and an associated mating plug-in connector element.

According to an exemplary embodiment, the mating plug-in connector element has an electrically conductive mating contact element with a cylindrical contact region, where in the plugged-in state of the plug-in connector the contact region of the electrically conductive mating contact element grips the contact protection element around. Such a concentric construction has the advantage of an especially compact construction and symmetrical force distribution when plugging in the connector elements.

In order to achieve especially good heat transfer and thus a short response time, it can be provided that the at least one temperature sensor is pressed onto the electrically conductive mating contact element in the plugged-in state of the plug-in connector.

So that both connector elements satisfy the requirements of contact safety for HV components, it can be provided that the mating plug-in connector element further has a second housing and a contact protection covering, where the contact protection covering is so disposed that between the second housing and the contact protection covering, access to the electrically conductive mating contact element is prevented for objects with a diameter above a defined value. For example, the contact protection covering is formed by an essentially ring-shaped electrically insulating synthetic part, which is arranged on a front-side end region of the electrically conductive mating contact element. Such a synthetic part can be manufactured cost-effectively and is either clipped or injection-molded onto a metallic contact element.

The advantageous properties of the invention's plug-in connector come into effect especially when the plug-in connector is implemented as a high-voltage plug-in connector for an electric vehicle.

For better understanding of the present invention, it is elucidated in more detail by means of the embodiments shown in the following figures. Here the same parts are given the same reference numerals and the same component designations. Furthermore also, some features or feature combinations from the various shown and described embodiments can represent separate independent, innovative, or inventive solutions. The figures show:.

In the following, the present invention is elucidated in more detail by reference to the figures, and in particular first by reference to the perspective view of <FIG>. Note that in all figures the size relationships and in particular the layer thickness relationships are not necessarily reproduced to scale.

<FIG> shows in the form of a schematic perspective view a contact protection element <NUM>, which finds use in a high-voltage (HV) round plug (e.g. with a diameter of <NUM>). Other plug-in connector geometries can of course likewise be designed with temperature detection according to the principles of the present invention.

According to an aspect of the present invention, the contact protection element <NUM> has an electrically insulating main body <NUM> with an elongated, in the assembled state columnar shape. For example, the main body <NUM> can be fabricated from a synthetic material.

According to the invention, a temperature sensor <NUM> is embedded in the main body <NUM> of the contact protection element <NUM>. The temperature sensor <NUM> can exhibit for example an NTC thermistor, a thermoelement, a resistance temperature sensor (e.g. Pt), or any other suitable temperature sensor.

NTC denotes 'negative temperature coefficient. " An NTC thermistor is a temperature sensor that uses the resistance properties of ceramic-metal composite materials for temperature measurement. NTC sensors offer many advantages for temperature measurement, e.g. small size, durable stability, high accuracy, and precision.

A thermoelement sensor consists of two unequal metals, joined to each other at one end. The temperature is measured at this branching. The two metals generate a small voltage, which can be measured and evaluated by a control system. The unequal metals are insulated individually, and with the help of a jacket a tight bifilar configuration is maintained. Thermoelement sensors have the advantage of a wide operating temperature range, largely constant sensitivity over their entire range, and availability in suitable miniaturized sizes.

Resistance sensors, known as RTDs (resistance temperature detectors), are sensors that are used for temperature measurement, in that the resistance varies proportionally to the temperature. RTD temperature sensors function even at locations with a harsh or hazardous environment with various official permits.

The temperature sensor <NUM> has a sensitive region <NUM> that performs the actual temperature detection, and an electrical connecting line <NUM> which connects the temperature sensor <NUM> with the necessary power supply and measured signal acquisition (not shown in the figures).

According to an aspect of the present invention, the connecting line <NUM> is routed through the main body <NUM> and emerges from the main body <NUM> at a base region <NUM>. Thereby the temperature sensor <NUM> and the connecting line <NUM> are protected optimally against mechanical stressing.

As becomes evident from the following <FIG>, the contact protection element <NUM> has at the base region <NUM> a radially surrounding latching ledge <NUM>, which engages with an associated latching groove <NUM> for fastening the contact protection element <NUM> in a plug-in connector element. A flange <NUM> serves in the assembled state for the sealing and mechanical support of the contact protection element <NUM>.

Advantageously, such a contact protection element <NUM> fitted with a temperature sensor <NUM> can be fabricated as a separate part e.g. through overmolding of the temperature sensor <NUM> and be held ready for the final assembly. Thereby, the mounting of a temperature sensor in a plug-in connector is significantly simplified.

<FIG> shows in perspective view an HV plug-in connector element <NUM> that is mounted on a current rail <NUM>. As is apparent from the synopsis with the sectional view of <FIG>, the contact protection element <NUM> is so arranged inside an electrically conductive socket contact <NUM> that access to the electrically conductive parts from outside is impossible for objects that have a larger diameter than a defined test probe. The plug-in connector element <NUM> comprises an electrically insulating housing <NUM>, which covers the socket contact <NUM> radially all around and on the front side in the insertion region.

The socket contact <NUM> comprises an electrically conductive contact main body <NUM>, which establishes the electrical junction to the current rail <NUM>. For electrical contacting of a mating plug-in connector (see <FIG>), the socket contact <NUM> comprises a spring contact <NUM>. The spring contact <NUM> comprises a large number of bilaterally fastened, radially inward curved flexible tongues <NUM>, which exert a contact pressure on the contact element of the mating plug-in connector. The inward curved region of the flexible tongues <NUM> forms in the plugged-in state of the plug-in connector the actual electrical contact region <NUM>, in which an undesirable heat buildup first occurs.

In order to detect overheating rapidly, according to a first advantageous aspect of the present invention the temperature sensor <NUM> is so arranged that its sensitive region <NUM> is located in immediate vicinity to the contact region <NUM>.

<FIG> elucidate the plugging together of the plug-in connector element <NUM> with a mating plug-in connector element <NUM> to form a plugged-in state of the plug-in connector <NUM>.

According to the shown embodiment, the mating plug-in connector element <NUM> comprises a hollow cylindrical electrically conductive mating contact element <NUM>, which when plugging together in the <NUM> direction grips the contact protection element <NUM> around and at the same time contacts it electrically from the outside through the spring contact <NUM>.

For electric insulation, the mating plug-in connector <NUM> has an electrically insulating second housing <NUM> and an electrically insulating contact protection covering <NUM>. The contact protection covering <NUM> is so formed that between the second housing and the contact protection covering, access to the electrically conductive mating contact element <NUM> is prevented for objects with a diameter above a defined value.

If one provides that the temperature sensor <NUM> at least in the sensitive region <NUM> projects slightly from the otherwise smooth outer surface of the contact protection element <NUM>, the temperature sensor is pressed in the plugged-in state on the inner surface of the electrically conductive mating contact element <NUM>. Thus an especially tight thermal contact is ensured and the temperature sensor <NUM> can respond especially rapidly and reliably to overheating in the critical region <NUM> marked by a dashed line.

<FIG> illustrate how the otherwise unmodified plug-in connector <NUM> can be modified in its temperature detection functionality by using different variants of the contact protection element <NUM>.

<FIG> shows again for comparison the arrangement elucidated by reference to <FIG>.

As shown in <FIG>, the temperature sensor can also be arranged closer at the base region <NUM> of the contact protection element <NUM>, in order to be able to monitor the temperature in the vicinity of the current rail.

Furthermore, it can also be provided that the temperature sensor is routed centrally through the contact protection element <NUM>, in order to make possible in this way on the one hand symmetrical temperature detection and on the other protect the temperature sensor mechanically.

Finally, each of the shown contact protection elements <NUM>, preferably the one shown in <FIG>, can also be used simply without temperature sensor <NUM>. This variant is shown in <FIG>.

All the variations shown in <FIG> can also be combined with each other, by using more than only one temperature sensor <NUM> or a sensor with more than one sensitive region <NUM>.

<FIG> illustrates again in a perspective view the invention's plug-in connector <NUM> in the plugged-in state.

In <FIG> the contact protection functionality of the plug-in connector element <NUM> is illustrated. As shown, a test probe <NUM> cannot penetrate into the free space between the contact protection element <NUM> and the housing <NUM> and touch the conductive parts, i.e. the socket contact <NUM>.

Likewise, as shown in <FIG>, the interaction of the second housing <NUM> with the contact protection covering <NUM> prevents the test probe <NUM> (and for this reason all objects that have a larger diameter than the test probe) touching the electrically conductive mating contact element <NUM>.

In summary, according to an exemplary aspect of the present invention, it is made possible through a new arrangement of the contact parts e.g. with a <NUM> round contact with the finger protection to situate the temperature sensor installation-space-neutrally and flexibly even in the immediate vicinity of the hotspot. The sensor is arranged in the contact protection element at the optimal position as regards contact layout. The necessary contact pressure of the sensor on the measurement surface is generated, depending on the mounting position, either by the plugging-in process or when assembling the contact protection. The connecting line of the sensor can also be reliably installed and routed away in the contact protection element. With this solution, the temperature measurement in the HV plug-in connector becomes more accurate and more flexible.

It should further be noted that although in the above description as an example always a round contact is described, nevertheless other contact cross-sections and also multiple contacts can of course likewise be designed according to the principles of the present invention.

Claim 1:
Plug-in connector element for detachable electrical contacting of a mating plug-in connector element (<NUM>), wherein the plug-in connector element (<NUM>) comprises:
at least one electrically conductive contact element (<NUM>),
a housing (<NUM>),
a contact protection element (<NUM>) which has a columnar structure and is arranged inside the at least one electrically conductive contact element (<NUM>) so that between the housing (<NUM>) and the contact protection element (<NUM>) access to the electrically conductive contact element (<NUM>) is prevented for objects with a diameter above a defined value, characterized in that
at least one temperature sensor (<NUM>), which at least in part is accommodated within the contact protection element (<NUM>) and can be operated to measure a temperature of the electrically conductive contact element (<NUM>).