Plug connection for releasable contacting of busbars

Abstract

The invention relates to a plug connection for releasable contacting of a first busbar and at least one second busbar, comprising a plug-connection connector for the electrically insulating enclosure of the first busbar and a plug-connection mating connector for the electrically insulating enclosure of the at least one second busbar, wherein the busbars are releasably electrically conductively contacted by contact elements and a locking screw secures the contact elements against release of the contact element connection.

Description

[0001] Description

[0002] Plug connection for detachable contacting of busbars

[0003] The invention relates to a plug connection for detachably contacting a first busbar and at least one second busbar, comprising a plug connection plug for electrically insulating the first busbar and a plug connection mating plug for electrically insulating the at least one second busbar.

[0004] Plug connectors, contacting elements, pole connectors, receptacles, etc., in a wide variety of designs and variants are used to make contact or create detachable, electrically conductive connections. Contact systems based on prismatic geometries for accommodating one or more contact pins have been developed, particularly but not exclusively for electrical contacting tasks in the higher power range.

[0005] High-voltage connectors are often designed with one or more plug contact pins and, in addition to reliable, detachable and durable contact, must also be protected against unintentional disconnection or disconnection caused by axial tensile loads.

[0006] One of the many possible applications for electrically conductive, detachable connectors is in vehicles, such as passenger cars with electric drives, where the electric drive motor is supplied with electrical energy by a high-voltage battery. Detachable or non-detachable electrically conductive connectors are also used within high-voltage batteries.

[0007] High-voltage batteries typically comprise a plurality of cells, each of which generates high electrical power and is connected in series. The cells—also known as modules—are electrically connected to form the series circuit using cables and plug-in connections or cell connectors. Due to the high electrical power flowing, the cross-sections of the cables are large, requiring high contact forces to connect them. Typically, the electrical conductors are pressed against each other using a screw connection and a contact element mounted between the two conductors. The contact elements of the electrically conductive connection to be realized are often formed by two busbars, for example, by an axial surface contact on the front side of the electrical transmission elements.The force required for contact is applied via a steel screw to ensure the necessary high axial preload. The tightening torque of the screw, which directly influences the screw preload, must be adhered to with great precision.

[0008] The high contact pressure generated by preloading the screw is necessary not only to move the electrical conductors or busbars, which are typically heavy and rigid for high direct currents, but also to smooth out surface irregularities through elastic deformation of the contact surfaces of the conductors and contact element pressed against each other, thereby achieving the largest possible contact area. The larger the area over which the electrical contact element and the electrical conductors serving as mating contacts are in direct contact, the lower the contact resistance. Low contact resistance reduces electrical losses and reduces the heat buildup of the connector.

[0009] The disadvantage of this solution is that, due to the high preload forces required, only high-strength metallic materials can be used for the tensioning screw, which are always electrically conductive. Since contact with the electrically conductive screw poses a life-threatening risk, especially in the higher electrical power range, access to it must either be prevented by enclosures or covered by an insulator, for example, plastic parts or a plastic overmold.

[0010] A permanent electrical contact suitable for higher and higher electrical power is demonstrated by DE 10 2015 000 988 B3, which discloses a method for producing an electrically conductive connection using a brazing process between copper wires and a copper strip carrier. The carrier is provided with a punched hole into which a brazing preform in the form of a rivet is placed and riveted to the carrier. The wires are then soldered to the rivet head by melting the brazing solder. DE 10 2017 205 360 B3 describes an electrical contact element and its method for producing a brazed, electrically conductive connection with a mating contact using a pressed-in brazing body.The electrical contact element is designed to create a bonded, electrically conductive connection with a mating contact, having at least one recess on a contact surface of the contact element and having a brazing body made of hard solder that is pressed into the recess and protrudes from the recess beyond the contact surface. To reduce the electrical contact resistance of the contact element, the contact element and the mating contact are pressed against each other at the contact surface by the preload forces of a screw, and the solder body is heated and melted, creating a bonded connection. The high preload forces required by the screw require high tightening torques, which can only be achieved with metallic screw materials of suitable strength.Since the screw must be accessible for assembly and is electrically conductive, contact protection must be provided, for example by a non-conductive housing and / or an insulating body.

[0011] The object of the invention is to further develop a plug connection suitable for the transmission of high electrical power in such a way that an integrated contact protection solution and a reliable electrically conductive detachable connection with reduced electrical contact resistance are sought and the disadvantages of known solutions are at least partially reduced.

[0012] The invention proposes a plug connection suitable for transmitting high electrical power, particularly in electric motor-driven vehicles and / or their energy storage devices, which has both an integrated contact protection solution and a locking mechanism secured against self-loosening. The plug connection according to the invention realizes the electrically conductive, detachable mechanical connection between two busbars or flat conductors, has at least one mechanical coding for the correct positional plug connection of the contact elements, and strives for integrated, minimized external dimensions of the plug connection. The invention recognizes that the detachable, electrically conductive contacting of the busbars can be provided particularly advantageously by a largely parallel position to one another and by using contact elements in the form of a combination of contact socket and contact pin.By utilizing the inherent contact forces of the contact elements, the invention eliminates the need for contact preload forces through a screw connection and limits the functional task of the screw preload force to locking or securing the plug connection against loosening. This makes it possible to design the required screw preload force for the locking function, which is much lower than the required preload force for the functional combination prevalent in the prior art, consisting of the sum of the contact force preload and the locking force preload.

[0013] Due to the reduced preload force required for the screw, limited to the locking force preload, the material strength of the screw can be selected significantly lower, enabling the use of materials with electrical insulation properties, such as plastic. This makes it possible to use the screw, consisting of a non-conductive material and thus providing quasi-integrated touch protection for the electrically conductive contact elements and busbars, without the need for additional insulating components or covers for the screw. This integration of touch protection eliminates the need for additional components for the screw with the touch protection function, thus supporting a cost-effective, simple, and space-saving design.The complete touch protection of the components involved in the electrical line, consisting of contact elements and busbars, is implemented by an at least one-piece housing of the plug connection with insulating properties, for example by means of plastic materials.

[0014] To further reduce the required installation space for the plug connection and thus its external dimensions of the at least one-piece housing, the invention provides in an optional embodiment that the thread required for the locking function of the screw is integrated in a threaded blind hole or a threaded bore in a contact element. To facilitate assembly and / or reduce the number of assembly components, the screw can be movably attached to a housing by means of a geometric design and secured against loosening in the assembled position after the tightening torque has been applied. The detachable, electrically conductive contact of the busbars is formed by contact elements consisting of a combination of contact socket and contact pin. The contact elements are compatible with one another such that the contact pin can be inserted into the contact socket.The contact socket has spring-elastic contact blades that apply the contact forces. The contact elements are each electrically conductively attached to a busbar with their axial extent, and thus their plug-in and contact-making direction, radial to the longitudinal extent of the busbars. The contact forces acting between the contact elements in the plugged-in state are radial to them and axially parallel to the longitudinal extent of the busbars. If a battery is to be electrically contacted with a consumer, a busbar is assigned to the battery and a busbar to a plug-in connector of the connector and are each arranged in an insulating housing together with the fixed contact element. When contacting cells within a battery, the busbars are each assigned to a battery cell.

[0015] The locking screw is inserted and screwed in, aligned and centered with the common center axis of the mated contact elements. The screw preload forces act axially toward the contact elements, whose contact forces are directed radially toward the center axis of the screw shaft and contact elements. The screw preload forces lock the contact elements in their mated position, so the screw function is limited to locking or securing the contact elements against loosening of the plug-in contact connection.The inventive design and positioning of the screw as a functional locking screw also has a particularly advantageous effect on the installation space requirement, since the screw is screwed directly within the contact element arrangement in a very space-saving manner. In this way, the locking elements commonly used in the prior art, for example, in the form of latches on the outer contour of the connector housing, are replaced, and the free outer housing surfaces are available, for example, for mechanical coding elements. The invention recognizes a further advantageous connection through the functional separation of the locking preload force and the contact preload force, which leads to the use of an electrically non-conductive screw material with reduced strength compared to steel materials.Despite the properties of reduced strength and frequently observed relaxation processes and the associated settlement of screw connections made of plastic, the functional separation of the locking and contact force according to the invention ensures that even in the case of such settlement processes and the associated preload losses, the contact force between the contact elements is not affected.

[0016] The invention is explained in more detail below using exemplary embodiments in conjunction with the figures. In the figures:

[0017] Fig. 1 shows a sectional side view of a first possible embodiment of the plug connection for releasably electrically contacting a first busbar and at least one second busbar;

[0018] Fig. 2 shows a sectional side view of a second possible embodiment of the plug connection for releasably electrically contacting a first busbar and at least one second busbar;

[0019] Fig. 3 a sectional detailed view of the locking screw with securing function and loss protection.

[0020] Figure 1 shows a sectional side view of a first possible embodiment of the plug connection 1 for releasably electrically contacting a first busbar 10 and at least one second busbar 20. The plug connection partners of this exemplary embodiment are formed by a plug connection plug 50 and a plug connection mating plug 60. Depending on the components to be contacted, the plug connection mating plug 60 is, for example, a battery (when a consumer, electric motor, or the vehicle electrical system of a vehicle is releasably electrically coupled to the battery as an electrical energy storage device) or a cell within a battery (when internal cells of the battery are electrically connected to one another). The plug connection plug 50 has the electrically conductive components in the form of the first busbar 10 and contact socket 30, 31 within a plug connection plug housing 51 and plug connection plug housing element 52.The electrically conductive coupling of the first busbar 10 and the contact socket 31 is achieved, for example, by pressing the contact socket 30, 31 into a bore of the busbar 10. The plug-in connector housing 51 and the plug-in connector housing element 52 are based on a material that is insulating against electrical energy, for example plastic, and house the electrically conductive components (10, 30, 31) within the formed housing interior, so that contact protection is realized.

[0021] The plug connection mating connector 60 has, within a plug connection mating connector housing 61 and plug connection mating connector housing element 62, the electrically conductive components in the form of a second busbar 20 and contact pin 30, 32. The electrically conductive coupling of the second busbar 20 and contact pin 32 is achieved, for example, by pressing the contact pin 30, 32 into a bore of the busbar 20. The plug connection mating connector housing 61 and the plug connection mating connector housing element 62 are based on a material that is insulating against electrical energy, for example plastic, and house the electrically conductive components (20, 30, 32) within the formed housing interior, so that contact protection is realized. Alternatively, it is possible to use the plug connection mating connector housing 61 and

[0022] Plug connection mating connector housing element 62 and the

[0023] The plug connector housing 51 of the plug connector 50 is to be constructed in such a way that, in the plugged-in state of the plug connection 1, the electrically conductive components (10, 20, 30, 31, 32) are enclosed in a contact-protected manner by the plug connector housing 51 and the plug connector housing element 52.

[0024] The busbars 10, 20, whose longitudinal extensions are largely axially parallel or in one plane, are contacted by their respective contact elements 30, 31, 32 through a radial plug-in direction. The contact elements 30, 31, 32 extend radially to the longitudinal extension of the busbars 10, 20 and can in turn be contacted by a plug-in movement in their axial direction. Thus, the locking screw 40, which is axially aligned with the contact elements 30, 31, 32, prevents the contact elements 30, 31, 32 from becoming loose and does not require any contact forces to be exerted between the contact elements 30, 31, 32.

[0025] The locking screw 40, with its function of locking or securing the contact elements 30, 31, 32 against loosening of the plug-in contact connection, achieves this function through the preload forces of the locking screw 40 through its tightening torque and acts in a preloading manner in the axial direction of the locking screw 40, which is axially parallel and aligned with the plug-in axis of the contact elements 30, 31, 32 and orthogonal to the plane of the extension direction of the busbars 10, 20. Due to the lower preload locking forces compared to a summary combination of preload locking force and contact preload force, the invention uses a locking screw 40 made of an electrically non-conductive material of lower strength, for example, plastic. This design eliminates the need for separate contact protection, i.e., the prevention of a person from coming into contact with electrically conductive components.

[0026] The locking screw 40 of this exemplary embodiment is arranged with its screw axis congruent with the plug-in axis of the contact elements 30, 31, 32. The screw-in thread is an internal thread 33 in the contact pin 30, 32, which is designed as a cylindrical hollow pin with a centrally and axially extending hollow bore in the form of a through-hole or a blind hole (a through-hole is shown here). The functional and spatial consolidation of the locking function by the locking screw 40 into the installation space of the contact elements 30, 31, 32 results in a particularly advantageous minimization of the overall installation space required for the plug connection 1.The design of the locking screw 40, consisting of an electrically non-conductive material, also reduces the installation space required for the plug connection because touch protection measures such as enclosing or covering the screw head, which must be accessible from the outside in order to tighten the locking screw 40, are no longer necessary. Also reducing installation space is the elimination of locking elements on the outer contour of the plug connection 1 by integrating the locking mechanism into the contact elements 30, 31, 32 and designing it as a locking screw 40 made of electrically non-conductive material. The locking screw 40 of the exemplary embodiment shown in Figure 1 is designed, in a first possible variant, as a simple push-through screw through a bore in the plug connector housing element 52.It is also possible to design the locking screw 40 as a through-bolt through a hole in the connector housing element 52 with a safeguard against loosening and / or to be movably fixed to the connector housing element 52 so that a loss protection and / or a pre-assembled assembly consisting of.

[0027] Plug connector housing element 52 and locking screw 40. This optional design variant is described in connection with the second embodiment in Figures 2 and 3.

[0028] The separation plane TR shown schematically in Figure 1 shows the plane from which the release and de-contacting of the plug connection plug 50 and the plug connection mating plug 60 of the plug connection 1 takes place when the locking screw 40 is at least loosened and, if necessary, also removed.

[0029] Figure 2 illustrates the sectional side view of a second possible embodiment of the plug connection 1 for detachably electrically contacting a first busbar 10 and at least one second busbar 20. The plug connection partners are formed by a plug connection plug 50 and a plug connection mating plug 60.

[0030] The plug connector 50 has, within a plug connector housing 51 and plug connector housing element 52, the electrically conductive components in the form of a first busbar 10 and contact pins 30, 32. The plug connector mating connector 60 has, within a plug connector mating connector housing 61 and plug connector mating connector housing element 62, the electrically conductive components in the form of a second busbar 20 and contact socket 30, 31.

[0031] The mating connector housing element 62 has an internal thread 63, aligned with the center axis of the contact elements 30, 31, 32, introduced into a through-bore or blind hole for screwing in the locking screw 40. The contact pin 30, 32 is designed as a cylindrical hollow pin with a centrally and axially longitudinally extending hollow bore in the form of a through-bore, so that the locking screw 40 can be guided through the through-bore and screwed into the internal thread 63 of the through-bore or blind hole of the mating connector housing element 62. The functions shown and explained in connection with Figure 1 apply equally to the second embodiment of Figure 2.

[0032] An optionally provided embodiment of the combination of locking screw 40 and connector housing element 52 is shown in the embodiment variant of Figure 2. Here, the locking screw 40 is movably attached to the connector housing element 52, thus providing a captive device and / or a preassembled assembly consisting of the connector housing element 52 and the locking screw 40. This captive assembly is realized in that the locking screw 40 has a constriction 41 of the screw shaft below its screw head, which has a smaller diameter than the screw shaft and the through-hole of the connector housing element 52.The length of the constriction 41 is adapted to the required axial mobility, at least to the level of the screw-in depth of the locking screw 40, into the internal thread 63 of the plug connector housing element 62 or into the internal thread 33 of the contact pin 30, 32, when the assembly is realized in connection with the first embodiment according to Figure 1.

[0033] To ensure that the locking screw 40 is secured against loss, the screw shaft is slightly oversized compared to the through-hole of the

[0034] Connector housing element 52. The assembly, consisting of locking screw 40 and connector housing element 52, is manufactured by pressing the locking screw 40 through the through-hole of the connector housing element 52. This is possible because the locking screw 40 is made of an electrically non-conductive material with lower material strength that has sufficient elastic deformability. Optionally, in addition to or as an alternative to the loss protection, a safety device 54, shown schematically here, can be provided to prevent the locking screw 40 from loosening. Figure 3 includes a sectional detailed view of the locking screw 40 and connector housing element 52 with a securing function in the form of the safety device 54 and the loss protection achieved by the assembly 40, 52.To implement the securing function against loosening of the screw connection, a variety of variants are generally considered: spring washers, toothed washers between the screw head and the bearing surface of the screw head on the connector housing element 52, screw locking using a locking adhesive between the threaded partners, and so on. Here, as an example, a toothing pair is realized and illustrated, formed from a radially outwardly extending external toothing 43, machined onto a screw head flange 42. The compatible mating toothing in the form of a radially inwardly extending internal toothing 56 is provided on the inside of a collar 55 of the connector housing element 52, which receives the screw head flange 42.The tooth pair 43, 56 secures the locking screw 40 in its tightened state against unintentional loosening, for example, due to vibrations caused by the meshing of the tooth pair 43, 56. This type of securing 54 is possible and supported by the elastic material behavior of the locking screw 40, which is formed from an electrically non-conductive material, such as plastic. This elasticity allows the at least partially required elastic deformation of the external tooth pair 43 when screwing in and tightening the locking screw 40, and the meshing of the tooth pair 43, 56 after tightening.When selecting the material for the connector housing element 52 and the collar 55 from an electrically non-conductive material with lower strength, the elastic material behavior is at least similar and offers similar elastic properties, so that in this case the internal toothing 56 also additionally realizes the partially elastic deformation. Reference numeral.

[0035] 1 plug connection

[0036] 10 first busbar

[0037] 20 second busbar

[0038] 30 contact element

[0039] 31 contact socket

[0040] 32 contact pin

[0041] 33 internal thread

[0042] 40 Screw, locking screw

[0043] 41 Constriction

[0044] 42 Bolt head flange

[0045] 43 External gearing

[0046] 50 plug connectors

[0047] 51 connector housings

[0048] 52 Connector housing element

[0049] 53 Coding

[0050] 54 Security

[0051] 55 collar

[0052] 56 internal gearing

[0053] 60 connector mating connectors

[0054] 61 connector mating connector housing

[0055] 62 Plug connection mating connector housing element

[0056] 63 internal thread

[0057] TR parting line

Claims

Claims 1. Plug connection (1) for detachably contacting a first busbar (10) and at least one second busbar (20), comprising a plug connection plug (50) for electrically insulating the first busbar (10) and a plug connection mating plug (60) for electrically insulating the at least one second busbar (20), characterized in that the busbars (10, 20) are detachably electrically conductively contacted by contact elements (30) and a locking screw (40) secures the contact elements (30) against loosening of the contact element connection.

2. Plug connection (1) according to claim 1, characterized in that the plug connection plug (50) and the plug connection mating plug (60) enclose the contact elements (30) in an electrically insulating manner.

3. Plug connection (1) according to claim 1, characterized in that the busbars (10, 20) lie with their longitudinal extent largely in one plane and the contact elements (30) are arranged with their plugging direction largely orthogonal to this plane.

4. Plug connection (1) according to claim 1, characterized in that the contact elements (30) are formed by a contact socket (31) and a contact pin (32) which are compatible with one another in terms of plugging and contacting.

5. Plug connection (1) according to claim 4, characterized in that the contact pin (32) is hollow and has a threaded blind hole or a threaded bore with an internal thread (33).

6. Plug connection (1) according to claim 1, characterized in that the plug connection plug (50) is formed by a plug connection plug housing (51) and at least one plug connection plug housing element (52).

7. Plug connection (1) according to claim 1, characterized in that the plug connection mating connector (60) is formed by a plug connection mating connector housing (61) and at least one plug connection mating connector housing element (62).

8. Plug connection (1) according to claim 7, characterized in that the plug connection mating connector housing element (62) has an internal thread (63).

9. Plug connection (1) according to claim 1, characterized in that the locking screw (40) is screwed axially aligned and congruent to the center axis of the contact elements (30, 31, 32).

10. Plug connection (1) according to claim 5 and 9, characterized in that the locking screw (40) is screwed into the internal thread (33) of the contact pin (32).

11. Plug connection (1) according to claim 8 and 9, characterized in that the locking screw (40) is screwed into the internal thread (63) of the plug connection mating connector housing element (62).

12. Plug connection (1) according to claim 1, characterized in that the locking screw (40) consists of a material with current insulating properties.

13. Plug connection (1) according to claim 6, characterized in that the locking screw (40) and the connector plug housing element (52) are movable relative to one another and are fixed to one another, so that a pre-assembled assembly is formed and the locking screw (40) is secured against loss.

14. Plug connection (1) according to claim 6, characterized in that the plug connection (1) has a safety device (54) against loosening of the screw connection, wherein the safety device (54) is formed by a tooth pair consisting of an external toothing (43) on the screw head flange (42) of the locking screw (40) and an internal toothing (56) on a collar (55) of the plug connection plug housing element (52).

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