Patent Application
20240145993
The present invention relates to a safety element for an electrical connector and to a connector having such a safety element.
Safety elements for electrical connectors known from the prior art always have the same mode of operation regardless of environmental influences. If a large amount of heat is generated due to a malfunction in the connector, this malfunction cannot be detected and the connector fails.
Based on this, the object of the invention is to create a safety element for a connector that allows dangerous malfunctions to be avoided and the associated damage to be prevented.
This object is attained by the features of claim 1. Furthermore, this object is attained by the features of claim 10. Advantageous embodiments and further developments are the subject of the subclaims.
According to the invention, an electrical connector has a safety element. This safety element is designed in such a way that it is an electrically insulating below a predetermined limit temperature. Furthermore, the safety element is designed in such a way that it is electrically conductive above the limit temperature.
Furthermore, according to the invention, a connector is provided comprising such a safety element or a safety element described further below.
The limit temperature is the temperature at which the electrical resistance or electrical conductivity of the safety element changes in such a way that the safety element becomes electrically conductive above the limit temperature. Below the limit temperature, the safety element is electrically insulating. This ensures that the safety element is designed in such a way that a connector having such a safety element has its intended functionality below the limit temperature in the sense of providing an electrical connection. Above the limit temperature, the safety element becomes electrically conductive and an intentional malfunction occurs in the connector. This malfunction can be, for example, a short circuit or an electrically measurable malfunction of the connector. This can also trigger a safety function.
In particular, the insulation resistance of the safety element is temperature dependent. This means that the insulation resistance changes with the temperature of the safety element. The insulation resistance of the safety element refers to the safety element as a structural unit, regardless of how many components the safety element comprises as a whole. The insulation resistance of the safety element can change, for example, due to melting of a component or part and/or due to temperature-dependent changes in the material properties (such as changes in electrical conductivity or electrical resistance) of individual components of the safety element.
A first threshold value of the insulation resistance (Riso) at which the safety element is considered electrically conductive in the sense of the invention may be, for example, 500 KF. Further, a second threshold value may be, for example, 100 KF.
Preferably, the limit temperature is such that even if the limit temperature is reached or exceeded, the connector is not damaged or destroyed but remains intact. This is achieved in particular by the limit temperature only occurring in a hottest zone of the connector holding at least part of the safety element.
In a further development of the invention, it is provided that the safety element is a secondary interlock that is preferably designed to lock together a first plug-in connection element and a second plug-in connection element of a plug-in connector. This defines that the safety element is a secondary interlock that is designed to secondarily interlock a connector, i.e. to provide an additional interlock to a primary interlock of a connector.
The secondary interlock may be a separate component from the first connector element and the second connector element that is formed independently of the first connector element and the second connector element of the connector. This allows the secondary interlock to be easily replaced, which may be necessary, for example, after the limit temperature has been exceeded.
In further development of the invention, it is provided that the limit temperature lies in a range from 200° C. to 250° C., preferably in a range from 210° C. to 240° C., further preferably in a range from 220° C. to 230° C. This ensures that the limit temperature that is preferably present only in the hottest zone of the connector, is in a temperature range in which damage to the connector is prevented.
In a further embodiment of the safety element, it is provided that the safety element is formed from a polymer that is electrically conductive above the limit temperature. This provides a safety element that is electrically conductive above the limit temperature due to its material properties.
In further development of the safety element, it is provided that the safety element comprises a base body made of a polymer that has a melting temperature corresponding to the limit temperature. This ensures that the base body melts when the limit temperature is reached.
In a further embodiment, it is provided that the base body of the safety element is formed from a polymer that is electrically conductive above the limit temperature.
Furthermore, in a further development of the safety element, it is provided that the base body is formed with at least one bore that accommodates at least one electrically conductive element.
In particular, the safety element is designed in such a way that, when the limit temperature is exceeded, the polymer from which the base body is formed melts and the at least one electrically conductive element is exposed, so that the safety element becomes electrically conductive when the limit temperature is exceeded. This ensures that electrical contact can be established through the electrically conductive element of the safety element, so that the safety element is electrically conductive. As a result, after the limit temperature has been exceeded once, the safety element becomes permanently conductive. If such a permanently conductive safety element is installed in a connector, the safety function is triggered until the safety element is replaced.
In an advantageous embodiment, the at least one electrically conductive element may be formed from a conductive polymer or a metal.
In a further advantageous embodiment, two bores are formed in the base body. An electrically conductive element is preferably in each bore.
In further aspects of the invention, the at least one electrically conductive element may be a pin.
In a further embodiment of the safety element, it is provided that the safety element comprises an element made of bimetallic material that is designed to change electrical resistance and/or shape depending on the temperature in such a way that it is electrically insulating below a limit temperature and an electrically conducting effect above the limit temperature.
In a further embodiment, this may be a reversible safety element that is electrically conductive when the limit temperature is exceeded and electrically insulating when the temperature falls below the limit again.
Furthermore, this can be a reusable safety element that allows the limit temperature to be exceeded and/or undershot several times.
It is further provided that the safety element comprises a shape-memory alloy that changes shape above the limit temperature so that the safety element becomes electrically conductive when the limit temperature is exceeded. Herein, another alternative embodiment is disclosed based on a change in shape of the safety element. In this way, an electrically conductive effect can also be reliably produced when used overhead or in other cases in which the function of a safety element could possibly be restricted.
In further development of the safety element, it is provided that the safety element is a shape memory element, preferably a 3D-printed element that is designed in such a way that it changes its shape above the limit temperature so that the safety element becomes electrically conductive when the limit temperature is exceeded. This makes it possible to realize shapes that cannot be realized by other manufacturing processes. Furthermore, as described above, the possibility of changing the shape means that an electrically conductive effect can be reliably produced even in overhead use or in other cases in which the function of a safety element might be restricted.
In a further development of the connector, it is provided that the connector is a HV connector (high-voltage connector). “High voltage” in the sense of the invention, refers here to alternating voltages (AC) of 30 V to 1 kV or to direct voltages (DC) of 60 V to 1.5 kV. This relates to a connector that meets the requirements of modern vehicle systems such as battery electric vehicles (BEV) or plug-in hybrid vehicles (PHEW).
Further, in another embodiment of the connector, it includes a first plug connector and a second plug connector.
Further, the safety element may be configured as a secondary interlock to lock together the first plug connector and the second plug connector.
Preferably, the connector also has a primary interlock in addition to the safety element designed as a secondary interlock.
In a further development of the connector, it is provided that in a secondary locked position of the connector, the safety element is in the hottest zone of the connector and is electrically conductive above the limit temperature, so that a planned malfunction of the connector occurs above the limit temperature.
In addition to the environmental parameters of temperature described above, a second environmental parameter, such as humidity, can also influence the electrical conductivity or electrical resistance of the safety element.
Further details and advantages of the invention will be apparent from the following embodiments described with reference to a drawing in which:
The safety element 10 according to
Such a secondary interlock is preferably configured to lock together a first connector element 110 and a second connector element 120 of the connector 100.
The limit temperature TLimit is preferably in a range from 200° C. to 250° C., further preferably in a range from 210° C. to 240° C., in particular in a range from 220° C. to 230° C.
The safety element 10 according to
Alternatively, the safety element 10 may comprise a base body 10′ made of a polymer having a melting temperature corresponding to the limit temperature TLimit. This ensures that the base body melts when the limit temperature is exceeded, exposing conductive elements of the safety element so that electrical contact is established.
As can be seen in
Further, the safety element 10 comprises at least one guide 18 for guiding and properly positioning the safety element 10 in the connector 100 or in the first connector element 110 and the second connector element 120 of the connector 100.
Furthermore, the safety element 10 has at least one latching surface that serves to latch the safety element in the connector 100 or in the first connector element 110 and the second connector element 120 of the connector 100.
The base body 10′ is formed with at least one bore 12. In general, the bore 12 accommodates an electrically conductive rod element 14. The safety element 10 is designed in such a way that, when the limit temperature TLimit is exceeded, the polymer from which the base body 10′ is formed melts and the at least one electrically conductive element 14 is exposed, so that the safety element 10 is electrically conductive when the limit temperature TLimit is exceeded.
Preferably, the conductive element is formed as a pin 14 and, as shown in
As can be seen from
According to the embodiment shown in
In this regard, the holes 12 are each formed in the projections 16 that serve to lock together the first connector element 110 and the second connector element 120 of the connector 100.
Preferably, the at least one bore 12 is designed as a blind hole or blind bore, so that it is only open at one end and so that the at least one electrically conductive element 14 can be pressed in through the open end. In the pressed-in state, the electrically conductive element 14 is surrounded by a uniformly thick material layer of the base body 10′ and only the opening through which the conductive element 14 was pressed in remains open.
Deviating from the second embodiment, only a single electrically conductive element 14 is formed in the third embodiment. The electrically conductive element 14 is formed such that it has a plurality of outer ends 14E, each outer end 14E being associated with a respective bore 12. Thus, the electrically conductive element 14 engages in all bores 12. When the limit temperature TLimit, is exceeded, the polymer from which the base body 10′ is formed melts and the electrically conductive element 14, in particular the outer ends 14E of the electrically conductive element 14 are exposed, so that the safety element 10 becomes electrically conductive when the limit temperature TLimit is exceeded. In the case of the third embodiment example according to
The second plug-in connection element 120 of the connector 100 has two electrical contacts 122, 124. The hottest zone H of the electrical connector 100 is located in the area of these electrical contacts 122, 124. The projecting parts 16 of the safety element 10 engage each of these electrical contacts 122, 124. If an impermissibly high temperature is reached at one of the electrical contacts 122, 124 in the form of the limit temperature TLimit being exceeded, the polymer of the respective projecting part 16 melts and electrical contact occurs. This is achieved by the pin 14 coming into electrical contact with the electrical contact 122, 124 of the second connector element 120. This triggers a measurable malfunction that can be detected so that it can be determined that the limit temperature TLimit in the connector 100 has been exceeded.
Preferably, the connector according to
The connector 100 has a first connector element 110 and the second connector element 120 already described with reference to
As described above with reference to
As already explained above, the safety element 10 has the guide 18. This guide 18 is formed as a groove, as can be seen clearly in
As can also be seen well in
Furthermore, the guide 18 and complementary guide formation 128 are configured such that the safety element 10 is guided relative to the second plug-in connection element 120 by the guide 18 and complementary guide formation 128.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 110 613.3 | Apr 2022 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/061105 | 4/26/2022 | WO |
