Device and method for establishing an electrical connection between an electrical traction energy storage unit and a high-voltage electrical system for a motor vehicle

Description

[0001] The invention relates to a device and a method for establishing an electrical connection between an electrical traction energy storage device and a high-voltage electrical system for a motor vehicle, as well as to a motor vehicle having the device.

[0002] For the general state of the art, reference is made to KR 10-1131735 B1. This discloses a high-voltage junction box for a vehicle used in a power control system for a hybrid or electric vehicle in which an inverter controls a drive motor using energy supplied by a vehicle battery. The high-voltage junction box includes a high-voltage control circuit with a high-voltage relay capable of connecting or disconnecting power by an external signal, and installed on an upper surface of a main block. Furthermore, the high-voltage junction box includes a bus bar formed in a three-dimensional structure for electrically connecting the high-voltage control circuit, and a high-voltage cable connection provided on a lower surface of the main block.Further, the high-voltage junction box includes a fixed shield for protecting the main block, which is fixed to and disposed within the vehicle, and a cover for protecting the high-voltage control circuit by covering the upper surface of the main block.

[0003] Hybrid, plug-in hybrid, fuel cell, and electric vehicles feature a traction energy storage system that stores and supplies recuperation and propulsion energy. Traction energy storage systems can be based on rechargeable batteries, such as lithium-ion batteries, or so-called supercapacitors, or contain a combination of such storage types. Typically, such traction energy storage systems have a modular design, with individual energy storage cells electrically combined into individual modules, which in turn are connected in series and / or parallel.

[0004] It is also known in practice to provide a battery junction box for traction energy storage units. The contactor box for high-voltage (HV) traction energy storage units consists of isolating elements and fuses to selectively disconnect and connect the live part of the traction energy storage unit from the high-voltage (HV) vehicle electrical system. Such devices, referred to as contactor boxes or contactor box arrangements, ensure that no dangerous voltage is present on parts at risk of contact, such as externally accessible contacts, etc.

[0005] A disadvantage of the contactor boxes known from the prior art is the potential hazards during assembly or disassembly caused by surfaces that are not protected against contact. For example, contactor boxes are known from the prior art that feature a contact-protected plastic component as a cover. Several interfaces of the contactor box are formed on such a plastic component, which are connected to the traction energy storage unit via busbars. It is important to note that contact protection is ensured by additional plastic components that cover the busbars and the interfaces.

[0006] To disassemble such a contactor box, all connections between the interfaces must be removed. However, this means that when a connection is removed, e.g., by dismantling a busbar, a non-contact-protected surface, namely the free interface of the contactor box, remains, but voltage is still present at the contactor box. This creates a potential hazard.

[0007] The invention is therefore based on the object of providing an improved technology for establishing an electrical connection between an electrical traction energy storage device and a high-voltage electrical system for a motor vehicle, which avoids the disadvantages of known approaches. In particular, the object is to provide a device with a contactor box arrangement that enables permanent contact-protected assembly and disassembly of the contactor box arrangement.

[0008] The problem is solved by the features of the independent claims. Advantageous further developments are specified in the dependent claims and the description.

[0009] According to a first general aspect of the invention, a device for establishing an electrical connection between an electrical traction energy storage device and a high-voltage electrical system for an (electrically powered) motor vehicle is provided. The device comprises a housing, preferably made of metal, particularly preferably aluminum, and a contactor box arrangement that is or can be connected to the housing by means of a first detachable connection. The connection of the contactor box arrangement to the housing can occur after inserting the contactor box arrangement into the housing (i.e., receiving the contactor box arrangement within the housing).

[0010] The contactor box arrangement has a switching device that is arranged on a carrier plate and is designed to selectively establish or break an electrical connection between a first terminal for connecting the electrical traction energy storage device and a second terminal for connecting the high-voltage vehicle electrical system. The contactor box arrangement further comprises a contact guard, preferably made of plastic, that is designed as a cover for the switching device and is connected or connectable to the carrier plate by means of a second detachable connection. The second detachable connection is preferably arranged such that it is not accessible when the device is in the assembled state. The device is in the assembled state when the contact guard is connected to the carrier plate by means of the second detachable connection (iethe contactor box assembly is assembled) and the (assembled) contactor box assembly is connected to the housing by means of the first detachable connection. The second detachable connection is inaccessible if it cannot be removed manually or with standard tools.

[0011] The device is advantageously designed such that the contactor box arrangement is permanently protected against contact during assembly, disassembly, and in the assembled state. A so-called box-in-box system is provided, wherein the contactor box arrangement (inner box of the box-in-box system) is arranged within the housing (outer box of the box-in-box system) in the assembled state. Due to its arrangement, loosening of the second detachable connection is impossible, and thus also removal of the contact protection, as long as the contactor box arrangement is inserted in the housing and the two terminals of the contactor box arrangement are electrically connected to the electrical traction energy storage device or the high-voltage vehicle electrical system. The contact protection cannot therefore be dismantled or bypassed before the device has been de-energized and the contactor box arrangement has been removed from the housing.

[0012] The arrangement of the second detachable connection in such a way that it is not accessible when the device is assembled means that the second detachable connection is only accessible to a user when the contactor box assembly is not inserted into the housing. Protection against direct contact according to specified IP (International Protection) ratings, e.g., IPXXB, is always guaranteed by this "fail-safe system," as it ensures permanent contact protection and thus safe assembly and disassembly of the contactor box assembly.

[0013] The housing can be designed exclusively to accommodate the contactor box assembly and, if applicable, the electrical connecting cables. The housing can be box-shaped and / or open on one side. One open side of the housing can be closed, for example, by means of a fastenable (screwable) cover. The contact guard can be box-shaped and / or open on one side, at least in sections. The contact guard and the carrier plate, e.g., projections formed on the carrier plate, can be designed to engage one another in a form-fitting manner, at least in sections. The carrier plate is preferably made of plastic.

[0014] According to a particularly preferred embodiment, the second detachable connection can be arranged in the assembled state of the device in the region of a gap between an outer surface of the contact guard and an inner surface of the housing and / or on a side of the support plate facing away from the contact guard. The gap can have a width of less than 2 cm, preferably less than 1 cm, or can be designed such that the second detachable connection rests against the inner surface of the housing.

[0015] Advantageously, the second detachable connection is not accessible when the device is mounted. A user cannot manually loosen the second detachable connection, i.e., with their fingers or with conventional tools, when the device is mounted, and thus cannot remove the contact protection in this state, thus ensuring permanent protection. Thus, for example, during disassembly, the device is protected against contact at all times, since the second detachable connection prevents the contact protection from being removed, and furthermore, it is not possible to loosen the second detachable connection because the distance between the housing and the contact protection is too small.

[0016] The second detachable connection can comprise one or more connections of different connection types. According to a further preferred embodiment, the second detachable connection can comprise at least one clip, snap, screw, and / or latching connection. In addition to the second detachable connection, at least one further detachable connection can be provided for connecting the contact protection to the carrier plate. The second detachable connection and the at least one further detachable connection can comprise connections of the same connection type.

[0017] It was stated above that the housing and the contactor box arrangement are or can be connected by means of a first detachable connection. According to a further preferred embodiment, the first detachable connection can comprise at least one screw that is captively inserted into the contact protection. The at least one screw can be inserted into a socket that is integrated in the contact protection. The at least one screw and / or the respective socket can be injection-molded components and / or made of plastic. The respective socket can be designed such that the at least one screw cannot be removed from the socket. The at least one screw can be specially (exclusively) designed to connect the contactor box arrangement to the housing.

[0018] Advantageously, this prevents the contactor box assembly from being connected to the housing if the contact guard is forgotten or not installed. The device can advantageously be designed in such a way that the contactor box assembly cannot be secured to the housing with "foreign" screws.

[0019] According to a further embodiment, the first connection can comprise a plurality of electrical cables, each of which is passed through one of a plurality of openings formed by the contact guard and / or the carrier plate and is connected (mechanically and electrically) to the switching device. The openings thus serve as cable passages. One end of each electrical cable can be connected directly, e.g., by screwing, to the switching device, preferably a contactor of the switching device. The first connection can be two-pole and comprise two, preferably four or more, electrical lines (cables). For example, two electrical lines (cables) can be provided for connection to a positive pole of the electrical traction energy storage device and two electrical lines (cables) can be provided for connection to a negative pole of the electrical traction energy storage device.

[0020] Advantageously, in contrast to the prior art, the contactor box assembly does not have any additional detachable electrical connection interfaces located on the outside, e.g., on the contact guard, which must each be electrically connected to the first connection via a busbar. Accordingly, when dismantling the contactor box assembly, no connections of such interfaces need to be removed, which would expose electrical contacts. Instead, the cables are routed through the openings (passages) into the interior of the contactor box assembly and screwed in place. This eliminates any potential hazards because no live components are exposed and live during assembly or disassembly. Furthermore, additional assembly steps and additional components, e.g., cables or busbars, are eliminated.

[0021] According to a further embodiment, at least one of the multiple openings can have an adjacent holder for one of the multiple electrical cables, which, when the device is assembled, is formed by a form-fitting connection between the contact guard and the support plate. The holder can be designed and arranged relative to the respective opening such that the cable emerging from the respective opening has a U-shaped, curved, wave-shaped, S-shaped, meandering, and / or labyrinthine course in this area.

[0022] Advantageously, each of the several cables can be led out of the contactor box arrangement and held in a fixed position.

[0023] According to a further embodiment, the plurality of electrical cables can each have an insulated (high-voltage) connector and can be guided or passed through openings in the housing. The lengths of the plurality of electrical cables can be dimensioned such that, in the assembled state of the device, each of the openings is occupied by one of the plurality of electrical cables. The lengths of the plurality of electrical cables can further be dimensioned such that, in the assembled state of the device, each of the insulated connectors is arranged (completely) outside the housing.

[0024] Advantageously, a simple electrical connection of the device to the electrical traction energy storage device and thus simple installation in a motor vehicle can be provided. By expediently selecting the lengths of the multiple electrical cables, it can be ensured that the electrical plug connections to the electrical traction energy storage device can only be made once the device is in the assembled state. The lengths of the electrical cables can also be dimensioned such that when the contactor box arrangement is removed from the housing, the electrical cables would preferably stretch after a short time and, furthermore, to completely remove the contactor box arrangement, the electrical cables would have to be disconnected from the plug connectors. This ensures that the supply voltage is automatically disconnected during removal.

[0025] Furthermore, the contactor box assembly can only be removed from the housing once the electrical plug connections have been disconnected, or the electrical plug connections are automatically disconnected when the contactor box assembly is removed, because removal of the contactor box assembly would otherwise be impossible due to the cable lengths. Due to the selected lengths of the multiple electrical cables and the optional holders formed in the contactor box assembly, it can be ensured that the electrical connections to the traction energy storage device are released by the respective tensile force on the multiple cables, for example, when the contactor box assembly is removed.

[0026] According to a further embodiment, the second terminal can comprise a (high-voltage) plug-in unit formed in the housing and at least one electrical line, preferably at least one busbar, for establishing an electrical connection between the plug-in unit and the switching device. The at least one electrical line can be covered by the contact guard when the device is in the assembled state. The second terminal can be bipolar and / or comprise two or more electrical lines.

[0027] Advantageously, a simple electrical connection of the device to the high-voltage electrical system can be provided, thus facilitating easy installation in a motor vehicle. At the same time, it ensures that the second connection is also permanently protected against contact.

[0028] According to a further embodiment, at least one contact screw, with which the at least one electrical line is or can be screwed to a contact of the plug-in unit, can be held captive by the contact guard in a receiving opening of the at least one electrical line or in a receiving opening for the at least one electrical line. The captive lock formed in the contact guard can have an opening for each of the at least one contact screw, which can be designed, for example, as a dome-shaped or elongated opening, through which the respective contact screw can be screwed using a tool. The at least one contact screw can be made of plastic.

[0029] Advantageously, the second terminal can only be electrically connected to the switching device once the contact protection is in place and the contactor box assembly is inserted into the housing. Furthermore, the contactor box assembly can only be removed from the housing once the electrical contact between the plug-in unit and the electrical cable has been broken by loosening at least one contact screw. This design ensures the contact protection requirements.

[0030] According to a further embodiment, a control unit for the preferably automated control of the switching device can also be arranged on the carrier plate, preferably wherein the control unit is arranged outside the contact guard when the device is in the assembled state. The switching device can comprise a sensor system for measuring a current conducted through the switching device (a current intensity and / or a current voltage) and at least one isolating element, preferably at least one contactor, for controllably establishing or disconnecting the electrical connection between the first terminal and the second terminal. The contactors can be the main contactors of the traction energy storage device. The switching device can also have at least one fuse, preferably at least one fusible link and / or a semiconductor protection element.The control unit can further be configured to control the at least one isolating element depending on the measurement. The control unit can be preprogrammed. The control unit can include predetermined conditions under which the electrical connection between the first terminal and the second terminal is to be established and / or broken based on the current values ​​and / or voltage values ​​measured by the sensors. The predetermined conditions can be stored in a memory of the control unit.

[0031] According to a second general aspect of the invention, a method for assembling a device for establishing an electrical connection between an electrical traction energy storage device and a high-voltage electrical system of a motor vehicle, preferably the device as disclosed herein, is provided. The method comprises assembling a contactor box arrangement by connecting a carrier plate to a contact guard, which is designed as a cover for a switching device arranged on the carrier plate, by means of a second detachable connection. The second detachable connection is preferably arranged such that it is not accessible when the device is in its assembled state. The method further comprises inserting the (assembled) contactor box arrangement into a housing and connecting the (assembled) contactor box arrangement to the housing by means of a first detachable connection.The method further comprises connecting the electrical traction energy storage device to a first terminal of the device and the high-voltage vehicle electrical system to a second terminal of the device, preferably after assembling the contactor box arrangement and after connecting the contactor box arrangement to the housing.

[0032] Advantageously, the device is designed in such a way that assembly is only possible in this sequence of process steps, thus permanently protecting the contactor box assembly from contact. In particular, the electrical connections to the electrical traction energy storage system and the high-voltage electrical system of the motor vehicle are only established once the device is already in the assembled state.

[0033] In order to avoid repetition, features previously disclosed purely in accordance with the device should also be considered as disclosed in accordance with the method and be claimable.

[0034] According to a further general aspect of the invention, a method is provided for disassembling a device for establishing an electrical connection between an electrical traction energy storage device and a high-voltage electrical system of a motor vehicle, preferably the device as disclosed herein. The method comprises disconnecting the electrical traction energy storage device from a first terminal of the device and the high-voltage electrical system from a second terminal of the device. The method further comprises releasing a first detachable connection that connects a contactor box arrangement to a housing and removing the contactor box arrangement from the housing. The method further comprises disassembling the removed contactor box arrangement by releasing a second detachable connection that connects a carrier plate to a contact guard that is designed as a cover for a switching device arranged on the carrier plate.The second detachable connection is preferably arranged such that it is not accessible in an assembled state of the device.

[0035] Advantageously, the device is designed in such a way that disassembly is only possible in this sequence of process steps, thus permanently protecting the contactor box assembly from contact. In particular, the electrical connections to the electrical traction energy storage unit and the high-voltage electrical system of the motor vehicle are initially disconnected or must be disconnected before the actual disassembly of the device takes place or before the actual disassembly can take place.

[0036] According to a further general aspect of the invention, an (electrically powered) motor vehicle is provided, comprising a device as disclosed herein. An electrical traction energy storage device is connected to the first terminal of the device, and a high-voltage vehicle electrical system is connected to the second terminal of the device. The device can be (directly) attached to the traction energy storage device. The traction energy storage device can comprise counterparts for insulated connectors of the plurality of cables of the first terminal.

[0037] The previously described embodiments, variants, and features of the invention can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings. They show: Figure 1 shows a schematic top view of a device according to an embodiment; Figure 2 shows a schematic side view of a contactor box arrangement according to an embodiment; Figure 3 shows a schematic section of a sectional view of the contactor box arrangement according to an embodiment; Figure 4 shows a schematic section of a sectional view of the device according to an embodiment; Figure 5 shows a schematic section of a top view of the device according to an embodiment; and Figure 6 shows a schematic representation of a method according to an embodiment.

[0038] For simplified understanding, the alignment of the device 100 or contactor box arrangement 10 according to the invention is shown in the Figures 1 to 5 using an exemplary Cartesian coordinate system, wherein, for example, the x-direction corresponds to a length direction, the y-direction to a width direction, and the z-direction to a height direction of the device 100 in an assembled state.

[0039] Figure 1 shows a schematic top view of the device 100 for establishing an electrical connection between an electrical traction energy storage device and a high-voltage electrical system for a motor vehicle. The device 100 is shown here in an assembled state.

[0040] The device 100 comprises a housing 12 and a contactor box arrangement 10, which in turn has a switching device 30, a carrier plate 14 and a contact protection 16.

[0041] In Figure 1 In the assembled state of the device 100 shown, the contactor box assembly 10 is inserted into the housing 12 and connected to the housing 12 by means of a first detachable connection 22. The first detachable connection 22 can comprise one or more screws 22 that are captively inserted into the contact protection 16.

[0042] The switching device 30 is arranged on the carrier plate 14 and is designed to selectively establish or break an electrical connection between a first terminal 18 for connecting the electrical traction energy storage device and a second terminal 20 for connecting the high-voltage vehicle electrical system.

[0043] The contact guard 16 is designed as a cover for the switching device 30 and is connected or connectable to the carrier plate 14 by means of a second detachable connection 26. The contact guard 16 is made of a non-conductive material, preferably a plastic. In the assembled state of the device 100 shown, the contact guard 16 is connected to the carrier plate 14, and the switching device 30 is accordingly arranged below the contact guard 16.

[0044] The device 100 is characterized, among other things, by the fact that the second detachable connection 26 is arranged such that it is not accessible in the assembled state of the device 100. For this purpose, the second detachable connection 26 can be arranged, for example, in the region of a gap 28 between an outer surface of the contact protection 16 and an inner surface of the housing 12.

[0045] This gap 28 can be configured such that a user cannot release or close the second detachable connection 26 manually or with conventional tools. The gap 28 can, for example, have a width of less than 2 cm or 1 cm or be configured such that the second detachable connection 26 rests against the inner surface of the housing 12. Alternatively or additionally, the second detachable connection 26 can be arranged on a side of the carrier plate 14 facing away from the contact guard 16.

[0046] The second detachable connection 26 can comprise at least one clip, snap, screw, and / or latching connection. In the illustrated embodiment, the second detachable connection comprises several lateral clip connections between the contact protection device 16 and the support plate 14, which are arranged in the region of the gap 28 in the assembled state, as well as screw connections between the contact protection device 16 and the support plate 14, which are only accessible from the underside of the contactor box assembly 10, i.e., from the side of the support plate.

[0047] The first terminal 18 can comprise a plurality of electrical cables 18, each of which is electrically and mechanically connected to the switching device 30 at one end and each having an insulated connector 24 at the other end. The electrical cables 18 and the insulated connectors 24 can be guided or passed through openings 48 of the housing 12, preferably with the lengths of the plurality of electrical cables 18 being dimensioned such that, in the assembled state of the device 100, each of the openings 48 is occupied by one of the plurality of electrical cables 18.

[0048] The second terminal 20 may comprise a plug-in unit 40 formed in the housing 12, which is electrically connected to the switching device 30.

[0049] Furthermore, a control unit 50 for controlling the switching device 30 can be arranged on the carrier plate 14, wherein the control unit 50 is arranged outside the contact protection 16 in the assembled state of the device 100. The control unit 50 can be connected to the switching device 30 via signaling, wherein the switching device 30 comprises a sensor system for measuring a current conducted through the switching device 30 and at least one isolating element, preferably at least one contactor, for controllably establishing or breaking the electrical connection between the first terminal 18 and the second terminal 20. The control unit 50 is designed to control the at least one isolating element depending on the measurement.During operation, the control unit can independently decide, based on predetermined conditions, at which current values ​​and / or voltage values ​​measured by the sensors the electrical connection between the first terminal and the second terminal should be established and / or broken. If a measured voltage value of the current conducted from the electrical traction energy storage device via the switching device 30 to the high-voltage vehicle electrical system is above a predetermined limit, for example, the control unit 50 can instruct the at least one disconnecting element to disconnect the electrical connection established by the switching device 30 and prevent possible damage to the electrical traction energy storage device and / or the high-voltage vehicle electrical system.

[0050] Figure 2shows a schematic side view of the contactor box arrangement 10 in an assembled state, ie the contact protection 16 is connected to the carrier plate 14 by means of the second detachable connection 26, which in this embodiment comprises several laterally arranged clip connections.

[0051] Figure 3 schematically shows a section of a sectional view of the contactor box assembly 10, in which, in particular, a captive screw 22 of the second detachable connection 22 is shown. The screw 22 is inserted into a socket 22A, which is integrated in the contact protection 16, wherein the respective socket 22A is designed such that the screw 22 cannot be removed from the socket.

[0052] As in Figure 4As shown, the electrical cables 18 of the first terminal 18 can each be passed through one of a plurality of openings 32 formed by the contact guard 16 and / or the support plate 14. At least one of the plurality of openings 32 can have an adjacent holder 38 for one of the passed-through electrical cables 18, which, in the assembled state of the device 100, is formed in a form-fitting manner by the contact guard 16 and the support plate 14.

[0053] The holder 38 can be formed by a curved, for example U-shaped or semicircular, recess 34 in the contact guard 16 and a projection 36 of the carrier plate. The recess 34 can have an open end 34A for inserting the at least one electrical cable 18 and a closed end 34B. In the assembled state of the device 100, the recess 34 and the projection 38 can engage with each other in a form-fitting manner, so that one of the electrical cables 18 is threaded and held in the closed end 34B of the recess 34. The holder 38 can also be referred to as a labyrinth.

[0054] Furthermore, as in Figure 4As shown, the length of the at least one electrical cable 18 is dimensioned such that the at least one electrical cable 18 is guided through the opening 48 of the housing 12 in the assembled state of the device 100 and the insulated plug connector 24 of the at least one electrical cable 18 is arranged completely outside the housing 12. The length of the electrical cables 18 is further dimensioned such that when the contactor box arrangement 10 is removed from the housing 12, the cables would stretch after a short time and, in order to completely remove the contactor box arrangement 10, the electrical cables 18 would have to be disconnected from the plug connectors 24. This ensures that the supply voltage is automatically disconnected during removal.

[0055] Figure 5schematically shows the second terminal 20, which comprises the plug-in unit 40 formed in the housing 12 and at least one electrical line 42, preferably at least one busbar, for establishing an electrical connection between the plug-in unit 40 and the switching device 30. In the illustrated assembled state of the contactor box arrangement 10, the at least one electrical line 42 is covered by the contact protection 16.

[0056] At least one contact screw 44 can be provided, with which the at least one electrical line 42 is screwed or can be screwed to a contact of the plug-in unit 40. The at least one contact screw 44 can be held captively in a receiving opening of the at least one electrical line 42 by the contact guard 16. For this purpose, a captive device 46 can be designed in the contact guard 16 in such a way that the at least one contact screw 44 is prevented from falling out of the receiving opening and preferably at least one opening is provided through which at least one contact screw 44 can be screwed to the contact of the plug-in unit 40 using conventional tools.

[0057] Figure 6 schematically illustrates the method for assembling the device 100 for establishing an electrical connection between an electrical traction energy storage device and a high-voltage electrical system of a motor vehicle.

[0058] In step S1 of the method 100, the contactor box arrangement 10 is assembled by connecting the carrier plate 14 to the contact protection 16 by means of the second detachable connection 26.

[0059] In steps S2 and S3 of the method 100, the assembled contactor box assembly 10 is inserted into the housing 12 and connected to the housing 12 by means of the first detachable connection 22.

[0060] In step S4 of method 100, the electrical traction energy storage device is connected to the first terminal 18 of the device 100, and the high-voltage electrical system is connected to the second terminal 20 of the device 100. This establishes the electrical connection between the traction energy storage device and the high-voltage electrical system.

[0061] Since the method is only possible in this sequence and thus an electrical connection of the device 100 with the electrical traction energy storage device and the high-voltage electrical system of the motor vehicle is only established when the device 100 is in the assembled state, the contactor box arrangement 10 is permanently protected against contact during the entire assembly and in the assembled state.

[0062] However, even when disassembling the device 100, it is ensured that the contactor box assembly 10 is permanently protected against contact. It is not possible to remove the contactor protection 16 from the carrier plate 14 and access "bare" live parts of the switching device 30, the first terminal 18, or the second terminal 20 as long as the traction energy storage device and the high-voltage electrical system are still electrically connected to the contactor box assembly 10. Instead, the electrical traction energy storage device is disconnected from the first terminal 18 and the high-voltage electrical system is disconnected from the second terminal 20, thereby "de-energizing" the contactor box assembly 10. The contactor box assembly 10 is then unscrewed from the housing 12, i.e., the first detachable connection 22 is released, and the contactor box assembly 10 is removed from the housing 12.

[0063] If an attempt is made to remove the contactor box assembly 10 from the housing 12 without disconnecting the electrical connections to the electrical traction energy storage device, the selected lengths of the plurality of electrical cables 18 and optionally also the at least one bracket 38 can result in the electrical connections to the traction energy storage device being disconnected by a respective tensile force on the plurality of cables 18. For example, the connectors 24 can thus be separated from their respective counterparts of the traction energy storage device.

[0064] If the contactor box assembly 10 is then located, for example, at the user's workstation, the second detachable connection 26 can be released and the contact protection 16 removed. Thus, the contactor box assembly 10 is permanently protected against contact when electrical voltage is applied, i.e., when it is connected to the traction energy storage device.

[0065] The invention is not limited to the preferred embodiments described above. Rather, numerous variants and modifications are possible that also utilize the inventive concept and therefore fall within the scope of protection. List of reference symbols

[0066] 10 Contactor box arrangement 12 Housing 14 Support plate 16 Contact protection 18 First connection, electrical cable 20 Second connection 22 First detachable connection, screw 22A Socket 24 Connector 26 Second detachable connection 28 Gap 30 Switching device 32 Opening 34 Cutout 34A, 34BOn or closed end of the cutout 36 Projection 38 Bracket 40 Plug-in unit 42 Electrical cable 44 Contact screw 46 Captive device 48 Breakout 50 Control unit 100 Device S1, S2, S3, S4 Process steps

Claims

1. A device (100) for establishing an electrical connection between an electrical traction energy storage unit and a high-voltage on-board electrical system for a motor vehicle, comprising: - a casing (12), preferably made of metal; and - a contactor box arrangement (10) connected or connectable to the casing (12) by a first detachable connection (22), comprising: - a switching device (30), arranged on a carrier plate (14) and configured to selectively establish or interrupt an electrical connection between a first terminal (18) for connecting the electric traction energy storage unit and a second terminal (20) for connecting the high-voltage on-board electrical system, and - a touch protection (16), preferably made of plastic, formed as a cover of the switching device (30) and connected or connectable to the carrier plate (14) by a second detachable connection (26), characterized in that the second detachable connection (26) is arranged such that it is not accessible in an assembled state of the device (100).

2. The device (100) according to claim 1, wherein the second detachable connection (26) is arranged in the mounted state of the device (100) in the region of a gap (28) between an outer surface of the touch protection (16) and an inner surface of the casing (12) and / or on a side of the carrier plate (14) facing away from the touch protection (16).

3. The device (100) according to claim 2, wherein the gap (28) has a width of less than 2 cm, preferably less than 1 cm, or is formed such that the second detachable connection (26) abuts against the inner surface of the casing (12).

4. The device (100) according to any one of the preceding claims, wherein the second detachable connection (26) comprises at least one clip, snap, screw, and / or latch connection.

5. The device (100) according to any one of the preceding claims, wherein the first detachable connection (22) comprises at least one screw (22) inserted into the touch protection (16) in a loose-proof manner.

6. The device (100) according to any one of the preceding claims, wherein the first terminal (18) comprises a plurality of electrical cables (18), each of which is passed through one of a plurality of openings (32) formed by the touch protection (16) and / or the carrier plate (14) and connected to the switching device (30).

7. The device (100) according to claim 6, wherein at least one of the plurality of openings (32) comprises adjacent thereto a holder (38) for one of the plurality of electrical cables (18), which, in the mounted state of the device (100), is formed in a form-fitting manner by the touch protection (16) and the carrier plate (14).

8. The device (100) according to one of claims 6 or 7, wherein the plurality of electrical cables (18) each comprise an insulated plug connector (24) and can be passed through or are passed through through-holes (48) of the casing (12), preferably wherein lengths of the plurality of electrical cables (18) are dimensioned such that, in the assembled state of the device (100), each of the through-holes (48) is occupied by one of the plurality of electrical cables (18).

9. The device (100) according to any one of the preceding claims, wherein the second terminal (20) comprises a plug-in unit (40) formed in the casing (12) and at least one electrical conduit (42), preferably at least one busbar, for establishing an electrical connection between the plug-in unit (40) and the switching device (30).

10. The device (100) according to claim 9, wherein the at least one electrical conduit (42) is covered by the touch protection (16) in the mounted state of the device (100).

11. The device (100) according to claim 10, wherein at least one contact screw (44), with which the at least one electrical conduit (42) is screwed or can be screwed to a contact of the plug-in unit (40), is held in a loose-proof manner in a receiving opening of the at least one electrical conduit (42) by the touch protection (16).

12. The device (100) according to any one of the preceding claims, wherein a control unit (50) for controlling the switching device (30) is arranged on the carrier plate (14), preferably wherein the control unit (50) is arranged outside the touch protection (16) in the mounted state of the device (100).

13. The device (100) according to claim 12, wherein the switching device (30) comprises a sensor means for measuring a current conducted through the switching device (30) and at least one separating element, preferably at least one contactor, for controllably establishing or interrupting the electrical connection between the first terminal (18) and the second terminal (20), and the control unit (50) is configured to control the at least one separating element as a function of the measurement.

14. A method for assembling a device (100) for establishing an electrical connection between an electrical traction energy storage unit and a high-voltage on-board electrical system of a motor vehicle, preferably the device (100) according to one of the preceding claims 1 to 13, comprising the steps of: - assembling a contactor box arrangement (10) by connecting a carrier plate (14) to a touch protection (16), designed as a cover of a switching device (30) arranged on the carrier plate (14), by a second detachable connection (26), the second detachable connection (26) being arranged such that it is not accessible in an assembled state of the device (100); - inserting the contactor box arrangement (10) into a casing (12); - connecting the contactor box arrangement (10) to the casing (12) by a first detachable connection (22); and - connecting the electric traction energy storage unit to a first terminal (18) of the device (100) and the high-voltage on-board electrical system to a second terminal (20) of the device (100).

15. A motor vehicle, comprising a device (100) according to one of the preceding claims 1 to 13, wherein an electrical traction energy storage unit is connected to the first terminal (18) of the device (100) and a high-voltage on-board electrical system is connected to the second terminal (20) of the device (100).