Electrical connection element

Abstract

An electrical connection element (10) in a vehicle comprises a first electrical contact (16) and a second electrical contact (20), which are electrically conductively connected within a connection housing (24) of the electrical connection element (10). The connection housing (24) has a housing part (30) which is thermally coupled to the first electrical contact (16) and the second electrical contact (20) and comprises a display element (32) made of an irreversibly thermally thermochromic material. The housing part (30) is arranged such that the display element (32) is invisible in a use state of the electrical connection element (10) and is visible in a maintenance state of the electrical connection element (10).

Description

Technical Field

[0001] The invention relates to an electrical connection element in a vehicle. Background Art

[0002] One of the most common causes of failure in the automotive sector is the interruption of the electrical connection of the respective vehicle, which can be caused, for example, by degradation effects of the components involved in the electrical connection system. Such degradation effects are influenced by environmental influences occurring during driving operation, such as vibrations, temperature, humidity and / or dirt formation. It is therefore necessary to protect the electrical connection system from degradation mechanisms. This is of decisive importance in particular for autonomous driving, in order to be able to ensure a high availability of the electrical connection system. Furthermore, it is desirable to be able to predict an impending failure before it occurs, in order to be able to replace the components involved in a timely manner.

[0003] It is known to provide the electrical contacts of the connection system with a protective coating and / or to counteract the degradation mechanisms by means of constructive measures, for example by using clips or damping grommets. It is also possible to use measuring systems that analyze the current, voltage and / or temperature of the connection system to estimate the effects of the degradation. However, such solutions involve considerable effort and costs.

[0004] From DE 20 2021 004 014 U1 an electrical connector element is known for use in an electrical power network of an installation that has to be maintained at certain time intervals. The electrical connector element has at least one heat-conducting component having a surface area that is visible in the contact position of the electrical contacts involved in the electrical connector element. The surface area is formed by an irreversible thermochromic material that shows an irreversible color change as soon as a threshold temperature is exceeded. A disadvantage of this configuration is that the surface area is always exposed, so that it is also subject to environmental influences, which can lead to degradation of the electrical connector element. Summary of the invention

[0005] The object of the present invention is to provide an electrical connecting element, the state of which can be checked easily and reliably.

[0006] According to the invention, the object is achieved by an electrical connection element in a vehicle, wherein the electrical connection element comprises a first electrical contact and a second electrical contact, which are electrically conductively connected in a connection housing of the electrical connection element. The connection housing has a housing part, which is thermally coupled to the first electrical contact and the second electrical contact and comprises a display element consisting of an irreversible thermochromic material. The housing part is arranged such that the display element is not visible in the use state of the electrical connection element and is visible in the maintenance state of the electrical connection element.

[0007] The display element makes it possible to easily draw conclusions about the state of the electrical connection element via the color state of the irreversible thermochromic material.

[0008] Irreversible thermochromic materials are materials which, when a material-specific threshold temperature (also called "switching temperature") is exceeded, show a color change which is not reversed again, even if the temperature drops below the threshold temperature again. In this way, even after the threshold temperature has been exceeded once, for example during driving operation of the vehicle, it is possible to easily and reliably determine at a later point in time, for example during maintenance of the vehicle, whether the color change has exceeded the threshold temperature at any point in the past and therefore there is a risk of failure of the electrical connection element. In this case, the electrical connection element can be actively replaced even before actual failure, in order to ensure the high performance of the vehicle.

[0009] According to the invention, the threshold temperature is selected such that it is below the critical failure temperature at which the electrical connection element no longer has adequate functionality.

[0010] For example, if the connection housing consists of a plastic which no longer has the necessary mechanical properties at a critical failure temperature of 150°C, the threshold temperature may be 140°C or less, for example 120°C.

[0011] The necessary temperature difference between the threshold temperature and the critical failure temperature depends in particular on whether the respective component fails suddenly or only deteriorates gradually when the critical failure temperature is reached.

[0012] Irreversible thermochromic materials can be produced, for example, by using irreversible thermochromic pigments, which are known and available worldwide. Such pigments can have different threshold temperatures and color changes, so that the desired temperature behavior for the intended location of use can be set with little effort.

[0013] According to the invention, it is also provided that the display element of the housing part is not visible in the use state of the electrical connection element, i.e., for example, in driving operation of the vehicle, but is visible in the maintenance state. In this way, the display element can be arranged in the use state so that it is at least partially protected from direct environmental influences. This is particularly important for electrical connection elements that are arranged near heat-generating components and / or liquid lines of the vehicle, for example in the engine compartment or near the drive battery. The reliability of the information about the state of the electrical connection element that can be obtained by the display element is thus increased, because errors caused by degradation effects on the display element itself can be avoided or at least reduced.

[0014] According to the invention, the electrical connection element can also be a component of a charging interface of the vehicle, wherein the first electrical contact or the second electrical contact is assigned to a charging station which can be connected to the vehicle via the charging interface. In this sense, the corresponding electrical contacts assigned to the charging station are not a component of the vehicle itself, but are only temporarily connected to the vehicle, for example during a charging process. Such charging interfaces need to be easily monitorable in particular, since they are particularly exposed to environmental influences, such as rain and dirt.

[0015] According to the invention, the display element is arranged such that it is thermally coupled to the first and second electrical contacts as an integral part of the housing part. Excessive heating at the electrical contacts of the electrical connection element therefore has a direct effect on the display element.

[0016] In a variant, the display element is a test pin which is arranged in a non-destructively detachable manner in the connection housing. In the maintenance state of the electrical connection element, the test pin can be removed and optically inspected to check the state of the electrical connection element.

[0017] Furthermore, it is possible for the test pin to be a component of a locking mechanism of the connection housing, so that the test pin, in addition to its function as a status indicator, also serves as a mechanical fixing means.

[0018] In another variant, the display element is an indicator surface which is covered, in particular completely covered, by the cover in the use state of the electrical connection element. In this variant, in the maintenance state of the electrical connection element, the cover can be removed, in particular non-destructively, or the cover can be transferred into a release position in which the indicator surface is optically visible.

[0019] For example, the cover is connected to the connecting housing via a hinge, so that the cover can be transferred into the release position by a rotational movement and release the indicator surface.

[0020] The indicator surface can be an integral part of the connection housing, for example by forming the material of the connection housing with an irreversible thermochromic material in a corresponding part of the connection housing.

[0021] It is also possible for the indicator surface to be subsequently applied to the connection housing, for example adhesively bonded, vapor-deposited or sprayed onto it.

[0022] The electrical connecting element can be a plug connector, and the connecting housing can have a first housing section assigned to the first electrical contact and a second housing section assigned to the second electrical contact.

[0023] The first housing portion and the second housing portion are detachable from one another, in particular in a non-destructive manner.

[0024] In plug connectors, degradation effects are attributable in particular to relative movements of the electrical contacts involved in the plug connection, relaxation of the tension between the electrical contacts involved and electrical insulation layers, such as oxides, on the electrical contacts involved. Furthermore, no mechanical means can be provided in the plug connector to counteract degradation mechanisms, since the plug connector has a maximum permissible plugging force in order to be able to be releasably mounted without damage. However, by using the display element according to the invention, the plug connector can also be monitored easily and reliably, so that other complex protection mechanisms against degradation effects can be omitted. This is particularly advantageous since a large number of plug connectors are used in vehicles, the state of which must be monitored.

[0025] Such a configuration is also suitable for the case where the electrical connection element is a component of a charging interface of the vehicle.

[0026] The display element can be a housing section of the first housing section and / or the second housing section. In this case, the housing section is covered by, for example, another housing section in the use state of the electrical connection element.

[0027] In an alternative variant, the electrical connection element is crimped and / or ultrasonically welded. In other words, the electrical connection element can be designed such that the first electrical contact and the second electrical contact cannot be loosened without destruction. In this way, a particularly mechanically load-bearing electrical connection element can be obtained, the state of which can be checked by means of a display element.

[0028] In order to obtain redundant information about the behavior of the electrical connection element, in addition to the display element which is not visible in the state of use of the electrical connection element, additional means can be provided which provide information about the state of the electrical connection element.

[0029] For example, the first electrical contact and / or the second electrical contact can be connected in an electrically conductive manner to a stranded wire which is coated with an insulating coating, wherein the insulating coating comprises a thermochromic material or consists of a thermochromic material.

[0030] It has been recognized that the increased heating at the electrical contacts of the electrical connection element due to the generally high thermal conductivity of such electrical contacts can also lead to heating of the components connected to the electrical contacts. Therefore, the state of the electrical connection element can also be monitored by means of the temperature development at these connection components. For this purpose, thermochromic materials can also be used in order to easily allow the state to be checked optically.

[0031] In particular, a two-stage inspection method is obtained in this way, in which an initial assessment is obtained by the color of the insulating coating of the stranded wire, which can also be optically accessed at any time, as to whether the electrical connection element has deteriorated to such an extent that it should be replaced. If this is the case, the display element, which is only optically accessible in the maintenance state, can be checked to obtain a second assessment.

[0032] It is also possible that the electrical connection element comprises a grommet or a seal in which the connection housing is at least partially accommodated, wherein the grommet or the seal comprises a thermochromic material or consists of a thermochromic material. In this way, a two-stage verification mechanism of the state of the electrical connection element is obtained similar to the insulating coating.

[0033] In a further variant, a carrier or housing of a busbar electrically connected to the electrical connection element comprises a thermochromic material, so that a first indication of the state of the electrical connection element is possible via the color behavior of the busbar.

[0034] Preferably, the electrical connection element is a component of the DC power grid of the vehicle. In other words, the electrical connection element is particularly suitable for use in the DC power grid of the vehicle, for example in the 12V onboard power grid of the vehicle.

[0035] In particular, if the electrical connection element is part of a charging interface of the vehicle, the electrical connection element can be part of both a DC network and an AC network, so that the charging interface can be provided for both charging processes with DC current and charging processes with AC current. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further features and characteristics of the invention emerge from the following description of exemplary embodiments, which are not to be understood in a limiting sense, and from the drawings. In the drawings:

[0037] Figure 1 schematically shows a first embodiment of an electrical connection element with a display element before a threshold temperature of the display element is reached;

[0038] Figure 2 shows that after exceeding the threshold temperature of the display element Figure 1 Electrical connection elements;

[0039] Figure 3 schematically illustrates a second embodiment of an electrical connection element before a threshold temperature of a display element is reached;

[0040] Figure 4 shows that after the threshold temperature of the display element has been exceeded Figure 3 Electrical connection elements;

[0041] Figure 5 schematically shows a third embodiment of an electrical connection element before reaching a threshold temperature of a display element,

[0042] Figure 6 shows that after the threshold temperature of the display element has been exceeded Figure 5 Electrical connection elements;

[0043] Figure 7 schematically shows a fourth embodiment of an electrical connection element before a threshold temperature of a display element is reached;

[0044] Figure 8 shows that after the threshold temperature of the display element has been exceeded Figure 7 Electrical connection elements;

[0045] Fig. 9 schematically illustrates a fourth embodiment of an electrical connection element before a threshold temperature of a display element is reached; and

[0046] Fig.10 shows that after the threshold temperature of the display element has been exceeded Fig. 9 Electrical connection elements. DETAILED DESCRIPTION

[0047] Figure 1 A schematic sectional view shows a first embodiment of an electrical connection element 10 according to the invention in a vehicle (not shown in detail). The vehicle is, for example, an at least partially electrically driven vehicle.

[0048] The electrical connection element 10 is a plug connector which is composed of two plug connector halves 12 and 14 which are connected to one another.

[0049] The plug connector half 12 is defined by a first electrical contact 16 to which the first housing section 18 is assigned, while the plug connector half 14 is defined by a second electrical contact 20 to which the second housing section 22 is assigned.

[0050] The first housing section 18 and the second housing section 22 together form a connecting housing 24 .

[0051] Figure 1 The electrical connection element 10 is shown in a state of use in which the first electrical contact 16 engages in the second electrical contact 20 , so that the two electrical contacts 16 and 20 are electrically connected to one another via a contact point 26 (schematically indicated in the figure by means of a star).

[0052] For this purpose, in the embodiment shown, the first electrical contact 16 is designed as a piercing sword, and the second electrical contact 20 is designed as a sleeve complementary to the piercing sword. It goes without saying that other forms of contact point 26 and designs of electrical contacts 16 and 20 are also possible.

[0053] The electrical contacts 16 and 20 are electrically connected to further components of the electrical wiring network of the vehicle via the wire ends 28, which will not be discussed in more detail here. For example, the electrical wiring network is a 12V on-board electrical network of the vehicle.

[0054] According to the invention, the connection housing 24 has a housing part 30 which is thermally coupled to the first electrical contact 16 and the second electrical contact 20. For example, the housing part 30 is arranged such that the heat generated at the contact point 26 can be discharged to the housing part 30 at least indirectly.

[0055] As in Figure 1 As can be seen in FIG. 3 , the housing part 30 comprises a display element 32 which is designed as a test pin 33 in the first embodiment.

[0056] The test pin 33 is connected to the handle element 34 and can be inserted in a non-destructively releasable manner into a recess 36 which extends through the connecting housing 24 , ie through the second housing portion 22 .

[0057] The test pin 33 thus projects into the interior of the connection housing 24 and terminates in the region of the contact point 26 without contacting it. In this way, heat transfer from the contact point 26 to the test pin 33 can be achieved via the atmosphere in the connection housing 24.

[0058] As long as the electrical connection element 10 is in use, the display element 32 , ie the test pin 33 , is therefore not visible from the outside but is exposed to the heat generated at the contact point 26 .

[0059] The test pin 33 comprises an irreversible thermochromic material, so that if the test pin 33 is heated above a threshold temperature, the color of the test pin 33 changes from an initial color, eg white, to a warning color, eg red.

[0060] The threshold temperature is selected such that it is reached as soon as so much heat is generated at the contact point 26 that this can be interpreted as an indicator of an impending failure of the electrical connection element 10. Thus, conclusions can be drawn reliably in time, via the color of the display element 32, about the state of the electrical contact point 26 or the electrical contacts 16 and 20 involved, before a failure occurs.

[0061] It goes without saying that the color change does not necessarily occur suddenly. It is also possible that the first partial area of ​​the test pin 33 has already shown a color change, while the second partial area of ​​the test pin 33 has not yet undergone a color change.

[0062] Figure 2 FIG. 1 shows the electrical connection element 10 after reaching the threshold temperature. It can be seen that the test pin 33 has changed color, such as Figure 2 As shown by the shaded lines in .

[0063] In a maintenance state of the electrical connection element 10 , for example during a scheduled inspection of a vehicle, the test pin 33 can be removed using the handle element 34 and optically inspected, as shown. Figure 2 Indicated by arrows.

[0064] Since the test pin 33 is covered toward the outside in the use state of the electrical connection element 10, the test pin 33 is protected from environmental influences, for example from dirt and moisture and temperature influences caused by components of the vehicle outside the electrical connection element 10. In this way, the display element 32 according to the invention enables particularly reliable reporting on the state of the electrical connection element 10.

[0065] Figure 3 A second embodiment of an electrical connection element 10 according to the invention is shown.

[0066] The second embodiment corresponds substantially to the first embodiment, so that only the differences will be discussed below. Identical or functionally identical components are provided with the same reference numerals and reference is made to the above statements.

[0067] In the second embodiment, the housing part 30 comprises a cover 38 which is connected to the connecting housing 24 , ie the second housing portion 22 , via a hinge 40 .

[0068] Thus, the cover 38 can be rotated from Figure 3 The initial position shown is adjusted to the release position, as indicated by the arrow.

[0069] In the second embodiment, the display element 32 is designed as an indicator surface 41 which is arranged between the cover 38 and the second housing portion 22 .

[0070] The indicator surface 41 is, for example, adhesively bonded, vapor-deposited or sprayed onto the second housing portion 22 .

[0071] In the use state of the electrical connection element 10 , the indicator face 41 is covered by the cover 38 and protected from environmental influences, while a maintenance state can be easily achieved and the indicator face 41 can be inspected by adjusting the cover 38 into the release position.

[0072] Figure 4 The electrical connection element 10 of the second embodiment is shown after a threshold temperature of the display element 32 , ie the indicator face 41 , has been reached.

[0073] Figure 5 A third embodiment of an electrical connection element 10 according to the invention is shown.

[0074] The third embodiment corresponds substantially to the preceding embodiments, so that only the differences will be discussed below. Identical or functionally identical components are provided with the same reference numerals and reference is made to the above statements.

[0075] In the third embodiment, the display element 32 is designed as a housing section 42 of the first housing section 18. In other words, the display element 32 is a component of the first housing section 18, wherein the first housing section 18 is composed of an irreversible thermochromic material in the part forming the housing section 42.

[0076] In this case, the housing section 42 is arranged such that it is not visible from the outside in the use state of the electrical connection element 10 . Figure 5 In the variant shown, this is achieved in that the first housing section 18 has a smaller outer diameter than the second housing section 22 and the first housing section 18 is inserted into the second housing section 22 , wherein the housing section 42 is completely accommodated by the second housing section 22 .

[0077] In the variant shown, the housing section 42 is arranged only at the first housing section 18. Figure 5 It goes without saying that the housing section 42 can also be shaped differently, for example forming a surrounding area of ​​the first housing section 18 .

[0078] Figure 6 The third embodiment is shown in the state after the threshold temperature of the housing section 42 has been reached, ie after an irreversible color change of the thermochromic material has taken place.

[0079] The two housing sections 18 and 22 can be detached from one another in a non-destructive manner in a maintenance state, so that the housing section 42 can be inspected.

[0080] Figure 7 A fourth embodiment of an electrical connection element 10 according to the invention is shown.

[0081] The fourth embodiment corresponds substantially to the previous embodiments, so that only the differences will be discussed below. Identical or functionally identical components are provided with the same reference numerals and reference is made to the above statements.

[0082] In the fourth embodiment, both the first electrical contact 16 and the second electrical contact 20 are each electrically conductively connected to the litz wire 44 , in particular by means of a crimp connection.

[0083] Each of the twisted wires 44 has an insulating coating 46 that electrically insulates the respective twisted wire 44 , wherein the insulating coating 46 is or includes an irreversible thermochromic material.

[0084] Accordingly, the electrical connection element 10 according to the fourth embodiment has two different components which can indicate degradation of the electrical contact point 26 : on the one hand, the display element 32 which in the variant shown is designed as a housing segment 42 similarly to the third embodiment, and on the other hand, the insulating coating 46 .

[0085] As shown in FIG. 1 , the state of the electrical connection element 10 after reaching the threshold temperature Figure 8 It can be seen that the litz wire 44 and therefore the insulating coating 46 are thermally coupled to the associated electrical contact 16 or 20 , respectively, as schematically indicated by arrows.

[0086] The increased temperature development at the contact point 26 therefore results in heating not only of the display element 32 but also of the insulating coating 46. This can indicate, by triggering an irreversible color change of the insulating coating 46, that the electrical connection element 10 has been transferred to the maintenance state and that the display element 32, which is better shielded from environmental influences than the insulating coating 46, should be checked.

[0087] The threshold temperatures of the display element 32 and the insulating coating 46 may be different in order to accommodate different distances from the touch-through point 26 .

[0088] Fig. 9 A fifth embodiment of an electrical connection element 10 according to the invention is shown.

[0089] The fifth embodiment corresponds substantially to the previous embodiments, so that only the differences will be discussed below. Identical or functionally identical components are provided with the same reference numerals and reference is made to the above statements.

[0090] In the fifth embodiment, the first housing section 18 is received in a grommet 48 which consists of or includes an irreversible thermochromic material.

[0091] It goes without saying that the second housing portion 22 can also have a grommet 48 , or the entire connecting housing 24 can be surrounded by the grommet 48 .

[0092] Similar to the grommet 48, a seal (not shown) may also be used.

[0093] In a fifth embodiment, similar to the fourth embodiment, a dual mechanism for estimating the state of the electrical connection element 10 is provided: both the display element 32 (designed as an indicator surface 41 in the variant shown similarly to the second embodiment) and the grommet 48 are thermally coupled to the contact point 26 and show an irreversible color change as soon as a corresponding threshold temperature is reached, wherein the threshold temperature of the grommet 48 can be different from the threshold temperature of the indicator surface 41.

[0094] If the color change is determined using the grommet 48, such as Fig.10 As shown, the cover 38 can then be transferred into the release position and the indicator surface 41 can be used to check whether the electrical connection element 10 should be replaced.

[0095] The grommet 48 simultaneously protects the first housing section 18 from environmental influences.

[0096] In summary, the electrical connection element 10 according to the invention is characterized by the easy and reliable possibility of being able to assess the state of the electrical contact point 26 , so that the electrical connection element 10 can be replaced before a failure occurs.

Claims

1. An electrical connection element (10) in a vehicle, wherein: The electrical connection element (10) comprises a first electrical contact (16) and a second electrical contact (20), wherein the first electrical contact and the second electrical contact are electrically conductively connected in a connection housing (24) of the electrical connection element (10). The connecting housing (24) has a housing part (30) which is thermally coupled to the first electrical contact (16) and the second electrical contact (20) and comprises a display element (32) made of an irreversible thermochromic material, and The housing part (30) is arranged in such a way that the display element (32) is not visible in a use state of the electrical connection element (10) and is visible in a maintenance state of the electrical connection element (10).

2. The electrical connection element according to claim 1, wherein: The display element (32) is a test pin (33) which is arranged in the connection housing (24) so ​​that it can be detached without causing damage.

3. The electrical connection element according to claim 1 or 2, wherein: The display element (32) is an indicator surface (41) which is covered by a cover (38) in the use state of the electrical connection element (10).

4. The electrical connector according to claim 3, characterized in that: The cover (38) is connected to the connecting housing (24) via a hinge (40).

5. Electrical connection element according to one of the preceding claims, wherein The electrical connection element (10) is a plug connector, and the connection housing (24) has a first housing section (18) assigned to the first electrical contact (16) and a second housing section (22) assigned to the second electrical contact (20).

6. The electrical connection element according to claim 5, wherein: The display element (32) is a housing section (42) of the first housing section (18) and / or the second housing section (22).

7. The electrical connection element according to any one of claims 1 to 4, wherein: The electrical connection element (10) is crimped and / or ultrasonically welded.

8. Electrical connection element according to one of the preceding claims, wherein The first electrical contact (16) and / or the second electrical contact (20) are electrically conductively connected to a stranded wire (44), which is coated with an insulating coating (46), wherein the insulating coating (46) comprises a thermochromic material or consists of a thermochromic material.

9. Electrical connection element according to one of the preceding claims, wherein The electrical connection element (10) comprises a grommet (48) or a seal in which the connection housing (24) is at least partially accommodated, the grommet (48) or the seal comprising or consisting of a thermochromic material.

10. The electrical connection element according to claim 1, wherein: The electrical connection element (10) is a component of a DC power system of the vehicle.

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