Hochvolt-System

Abstract

The invention relates to a high-voltage system comprising: - a high-voltage cable (1) with a conductor (2), an inner insulation (3), a shield (4) in the form of a braided shield, and an outer insulation (5), - a plug-in and / or screw connector (6), comprising a shielding sleeve (8) contacted with the shield (4) and led out of one end of a housing (7) with at least one contact spring, a conductor pin (9) contacted with the conductor (2) and led out of the end of the housing (7), and an insulation (10) between the shielding sleeve (8) and the conductor pin (9), - a high-voltage unit with a unit housing (11), a busbar (13) and a pin tray with a busbar contact (12) contacted with the busbar (13) and a housing contact (14) contacted with the unit housing (11), wherein the conductor pin (9) can be contacted with the busbar contact (12), wherein the shielding sleeve (8) can be contacted with the housing contact (14), wherein the shield (4) and / or the shielding sleeve (8) and / or the housing contact (14) is interrupted at one point and at least one device (16, 17, 18) for regulating shield currents, comprising a defined ohmic resistance, is integrally connected to the shield (4), the shielding sleeve (8) or the housing contact (14) on both sides of the interrupted point.

Description

[0001] The invention relates to a high-voltage system according to the preamble of claim 1.

[0002] For energy transmission in the high-voltage electrical systems of battery-electric vehicles (BEVs), shielded high-voltage cables and shielded plug and / or screw connections are used to improve the vehicle's EMC properties. The electrical voltage induced in the shield results in a current flow (shield current) in the cable shields and shield contacts. Particularly in AC applications, the induced shield current can exceed 50% of the conductor current. The resulting undesirable ohmic resistance heating in the shield often requires oversizing the cable and contact cross-sections to counteract overheating. Furthermore, the ohmic resistance of the entire system increases due to the heating, which increases thermal losses and reduces the vehicle's range.In the event of a fault (e.g. short circuit), there are no protective devices for the shielding system, which in extreme cases leads to the destruction of the shield contacts and requires the replacement of the entire cable set.

[0003] To counteract high heat development in the shield, conductor cross-sections and contact surfaces are oversized, which leads to increased weight and costs in the vehicle.

[0004] DE 10 2017 005 597 A1 describes a high-voltage electrical cable for a motor vehicle with an electrical inner conductor and electrical insulation surrounding the electrical inner conductor. The high-voltage electrical cable is characterized by a soldered joint for electrical contact with a connector using a resistance soldering process, wherein the soldered joint comprises an aluminum shield, a flux-containing aluminum solder, and a shield connection element. The resistance soldering process allows the flux-containing aluminum solder to be liquefied and used as a contact element between the aluminum shield and the shield connection element. Due to the heat input during the resistance soldering process, the formation of an insulating aluminum oxide layer is reduced or prevented.

[0005] The patent application DE 10 2017 219 493 A1 aims to provide a solution with which the shield current and / or the radiation behavior of high-current cables, in particular coaxial cables, and high-current connectors can be optimized and specifically influenced. This is achieved by a module for high-current connectors and / or high-current cables, which comprises at least one coupling surface for connecting to the shield of the high-current cable and a device for specifically influencing the electromagnetic properties of the shield.

[0006] The invention is based on the object of providing a novel high-voltage system with which the level of the induced shield current can be specifically influenced.

[0007] The object is achieved according to the invention by a high-voltage system having the features of claim 1.

[0008] Advantageous embodiments of the invention are the subject of the subclaims.

[0009] A high-voltage system, in particular for an electrically powered vehicle, is proposed, comprising: - a high-voltage cable with a conductor, an inner insulation arranged concentrically around the conductor, a shield in the form of a braided shield arranged concentrically around the inner insulation, and an outer insulation arranged concentrically around the shield, - a plug-in and / or screw connector, comprising a housing, a shielding sleeve contacted with the shield and led out of one end of the housing with at least one contact spring, a conductor pin contacted with the conductor and led out of the end of the housing, and insulation between the shielding sleeve and the conductor pin, - a high-voltage unit with a unit housing, a busbar and a pin tray with a busbar contact contacted with the busbar and a housing contact contacted with the unit housing, wherein the conductor pin is contacted or contactable with the busbar contact, wherein the shielding sleeve is contacted or contactable with the housing contact, wherein further insulation is arranged between the housing contact and the busbar contact.

[0010] According to the invention, the shield and / or the shield sleeve and / or the housing contact are / is interrupted at one point and at least one device for regulating shield currents, comprising a defined ohmic resistance, is integrally connected to the shield, the shield sleeve or the housing contact on both sides of the interrupted point.

[0011] The solution according to the invention allows a reduction of the cable cross-sections, enables a reduction of thermal losses and provides electrical protection for the shielding system.

[0012] Embodiments of the invention are explained in more detail below with reference to drawings.

[0013] Showing: Fig. 1 a schematic view of a shielded high-voltage cable, Fig. 2 a schematic view of the high-voltage cable with a plug and / or screw connector, Fig. 3 a schematic view of the high-voltage cable with the plug and / or screw connector, which is contacted with a unit housing of a high-voltage unit, Fig. 4 a schematic view of the high-voltage cable with the plug and / or screw connector, which is in contact with the unit housing of the high-voltage unit, wherein at least one device for regulating shield currents is provided, Fig. 5 schematically shows a method for attaching the device to the shield of the high-voltage line, Fig. 6 a schematic view of an embodiment of the device with cooling channels, and Fig. 7 a schematic view of an embodiment of the device with an electrical fuse.

[0014] Corresponding parts are provided with the same reference numerals in all figures.

[0015] Fig. 1 is a schematic view of a shielded high-voltage cable 1 with a conductor 2 as core, an inner insulation 3 arranged concentrically around the conductor 2, a shield 4 in the form of a braided shield arranged concentrically around the inner insulation 3, and an outer insulation 5 arranged concentrically around the shield 4.

[0016] High-voltage cables 1 in a high-voltage electrical system of a vehicle are Fig. 1 shown shielded.

[0017] Fig. 2 is a schematic view of the high-voltage cable 1 with a plug and / or screw connector 6, comprising a housing 7, a shielding sleeve 8 contacted with the shield 4 and protruding from one end of the housing 7 with at least one contact spring, a conductor pin 9 contacted with the conductor 2 and protruding from the end of the housing 7, and an insulation 10 between the shielding sleeve 8 and the conductor pin 9.

[0018] Fig. 3 is a schematic view of the high-voltage cable 1 with the plug and / or screw connector 6, which is contacted with a unit housing 11 of a high-voltage unit.

[0019] Since the shield 4 is to be contacted to the unit housing 11 of a high-voltage unit, the plug and / or screw connector 6 has an element for contacting in the form of the shield sleeve 8 with contact spring(s).

[0020] Conductor pin 9, and thus conductor 2, is contacted via a busbar contact 12 of a pin tray to a busbar 13 of the high-voltage unit. Shield 4 is contacted via the shield sleeve 8 to the unit housing 11 of the high-voltage unit. For this purpose, a housing contact 14 of the pin tray can also be arranged on the unit housing 11. An additional insulation 15 can be arranged between the housing contact 14 and the busbar contact 12.

[0021] To ensure sufficient EMC properties of the shielding system, the contact resistances must be as small as possible.

[0022] The resulting shield current follows the voltage induced in the shield system according to Ohm's law. By introducing a defined ohmic resistance, the resulting shield current can be regulated. According to the invention, a current induced in the shielded high-voltage cable 1 and the resulting heat development are regulated by a defined ohmic resistance. This enables downsizing and overheating protection with a safety effect of the shield system.

[0023] Fig. 4 is a schematic view of the high-voltage cable 1 with the plug and / or screw connector 6, which is contacted with the unit housing 11 of the high-voltage unit, wherein at least one device 16, 17, 18 is provided for regulating shield currents.

[0024] The introduction of a defined ohmic resistance to regulate the resulting shielding current is possible without deterioration of the EMC properties by integrating the resistance and / or the device 16, 17, 18 into the shielding system in a material-to-material manner.

[0025] In Fig. 4 shows possible positionings of the devices 16, 17, 18 by way of example. For example, a device 16 can be arranged on or in the shield 4 of the high-voltage cable 1. Alternatively or additionally, a device 17 can be arranged on or in the shield sleeve 8. Alternatively or additionally, a device 18 can be arranged on or in the housing contact 14.

[0026] The device 16, 17, 18 can have a constant or temperature-dependent or adjustable ohmic resistance. The device 16 arranged on the shield 4 of the high-voltage cable 1 can be designed as a crimp sleeve 20 with a defined ohmic resistance. The integral connection can be established, for example, by electromagnetic pulse welding. A suitable coating of the crimp sleeve 20 maintains the insulating function and sealing effect of the outer insulation 5.

[0027] Fig. 5A to 5D schematically show a method for attaching the device 16 to the shield 4 of the high-voltage line 1. In Fig. 5A, the high-voltage line 1 is still undamaged. In Fig. 5B, the outer insulation 5 and the shield 4 were partially removed from the high-voltage line 1, so that the shield 4 is interrupted at this point, with the outer insulation 5 being removed in an area with a greater length than the shield 4, the removed area of ​​which lies within the removed area of ​​the outer insulation 5. In Fig. 5C, a spacer sleeve 19 was inserted into the removed area of ​​the shield 4, and a crimp sleeve 20 was pushed over the area where the outer insulation 5 was removed. The crimp sleeve 20 comprises a material with a defined resistance, which can be provided, in particular coated, with insulation 21 at least on an outer side and on the end faces of the crimp sleeve 20. The insulation 21 can further extend to an inner side of the crimp sleeve 20 at its ends and thus also serve to seal the crimp sleeve 20 against the outer insulation 5 of the high-voltage cable 1. A central area of ​​the inner side of the crimp sleeve 20, which lies over areas of the shield 4 and the spacer sleeve 19 exposed as a result of the removal of the outer insulation 5, is not provided with insulation 21. In Fig. 5C, the device 16 is ready for EMP welding and / or crimping. In Fig. 5D, the crimp sleeve 20 was formed by a crimping device using at least one electromagnetic pulse and the application of, for example, radially inwardly directed forces F. The central region of the crimp sleeve 20 is pressed into the recess formed by removing the outer insulation 5 and is firmly bonded to the shield 4 in contact areas 22 on both sides of the spacer sleeve 19. The insulation 21 on the inside of the crimp sleeve 20 at its ends serves as a seal 23 of the crimp sleeve 20 against the outer insulation 5 of the high-voltage cable 1.

[0028] Fig. 6 is a schematic view of an embodiment of the device 16, wherein cooling channels 24 are introduced into the area of ​​the crimp sleeve 20 lying above the spacer sleeve 19 and thus through which current can flow, through which a cooling medium can flow in order to cool the device 16.

[0029] Fig.7 is a schematic view of an embodiment of the device 16, wherein an electrical fuse 25 in the form of a region with a reduced material cross-section is introduced into the region of the crimp sleeve 20 lying above the spacer sleeve 19 and thus through which current potentially flows.

[0030] The device 16, 17, 18 can be used on a high-voltage system of an electrically powered vehicle, for example a commercial vehicle, a bus or a passenger car. List of reference symbols 1 high-voltage cable 2 conductors 3 internal insulation 4 umbrella 5 external insulation 6 screw connectors 7 housings 8 shielding sleeve 9 conductor pin 10 Insulation 11 Unit housing 12 Busbar contact 13 Busbar 14 Housing contact 15 Insulation 16 Device 17 Device 18 Device 19 Spacer sleeve 20 crimp sleeves 21 Insulation 22 Contact area 23 Seal 24 cooling channel 25 Fuse F Force

Claims

[1] High-voltage system, comprising: - a high-voltage cable (1) with a conductor (2), an inner insulation (3) arranged concentrically around the conductor (2), a shield (4) in the form of a braided shield arranged concentrically around the inner insulation (3), and an outer insulation (5) arranged concentrically around the shield (4), - a plug-in and / or screw connector (6), comprising a housing (7), a shielding sleeve (8) contacted with the shield (4) and led out of one end of the housing (7) with at least one contact spring, a conductor pin (9) contacted with the conductor (2) and led out of the end of the housing (7), and an insulation (10) between the shielding sleeve (8) and the conductor pin (9), - a high-voltage unit with a unit housing (11), a busbar (13) and a pin tray with a busbar contact (12) contacted with the busbar (13) and a housing contact (14) contacted with the unit housing (11), wherein the conductor pin (9) is contacted or contactable with the busbar contact (12), wherein the shielding sleeve (8) is contacted or contactable with the housing contact (14), wherein a further insulation (15) is arranged between the housing contact (14) and the busbar contact (12), characterized by that the shield (4) and / or the shield sleeve (8) and / or the housing contact (14) are interrupted at one point and at least one device (16, 17, 18) for regulating shield currents, comprising a defined ohmic resistance, is integrally connected to the shield (4), the shield sleeve (8) or the housing contact (14) on both sides of the interrupted point. [2] High-voltage system according to claim 1, characterized by that the defined ohmic resistance is designed as a constant or temperature-dependent or adjustable ohmic resistance. [3] High-voltage system according to claim 1 or 2, characterized by that the device (16) arranged on the shield (4) comprises a crimp sleeve (20) with a defined ohmic resistance. [4] High-voltage system according to claim 3, characterized by that the material-locking connection between crimp sleeve (20) is made by electromagnetic pulse welding. [5] High-voltage system according to claim 3 or 4, characterized by that the crimp sleeve (20) is provided, in particular coated, with an electrical insulation (21) on an outer side, on its end faces and at both ends of an inner side. [6] High-voltage system according to one of claims 3 to 5, characterized by that a spacer sleeve (19) made of an electrically insulating material is arranged in the interrupted point of the shield (4). [7] High-voltage system according to one of claims 3 to 6, characterized by that cooling channels (24) through which a cooling medium can flow are introduced into the crimp sleeve (20). [8] High-voltage system according to one of claims 3 to 6, characterized by that an electrical fuse (25) is incorporated in the crimp sleeve (20).

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