Device for electrical power distribution in a motor vehicle and busbar arrangement for a motor vehicle

Abstract

The invention relates to a device for electrical power distribution in a vehicle (2) having a stacked busbar arrangement (4) with a supply conductor (16) and with an earth conductor (18) which bear against one another and are each in the form of flat conductors, and having a vehicle body component (10) along which the busbar arrangement (4) is guided, wherein the earth conductor (18), at least in the regions in which it bears against the supply conductor (16) and preferably also in relation to the vehicle body component (10), is in the form of a blank metal conductor without insulation. The earth conductor (18) rests, in particular, on the blank vehicle body component (10) which is, in particular, a battery cover of a traction battery (12). This results in an improved EMC property, a small installation space requirement and good cooling.

Description

[0001] Description

[0002] Device for electrical power distribution in a motor vehicle and busbar arrangement for a motor vehicle

[0003] The invention relates to a device for electrical power distribution in a motor vehicle and a busbar arrangement for electrical power distribution for a motor vehicle.

[0004] The device is part of a motor vehicle electrical system, via which a large number of electrical components in the motor vehicle are supplied with electrical energy and electrical power. The busbar arrangement is used, for example, as a battery cable or generally as a main supply line, the so-called backbone. Such a cable is usually led from the front of the vehicle to the rear of the vehicle. The busbar arrangement is typically designed to transmit high currents of at least several 10 A, typically more than 100 A. Such a main supply line can be used both in low-voltage electrical systems with an on-board voltage of less than 60 V, for example 12 V or 48 V, or for high-voltage applications, for example in connection with electric motor-driven vehicles with voltages in the range of several 100 V and, for example, in the range of 300 V to 1000 V.

[0005] Such busbar arrangements often involve direct current lines (DC lines), where one busbar is designed as a supply line (forward conductor) and is connected to a positive reference potential during operation, for example to a positive terminal of the battery. The other busbar is designed as a ground line (return conductor), which is connected to the ground potential and / or to the negative terminal of the battery. In such main supply lines (backbone), strong magnetic fields can arise due to the high direct currents, which in unfavorable cases can lead to high, unacceptable magnetic fields in the passenger compartment. This problem occurs particularly in electric motor-driven vehicles, where a traction battery is often located below the body floor and electrical supply lines are then laid in the passenger compartment.This eliminates the shielding effect of the body floor that would otherwise be present.

[0006] Due to the high currents, the thermal load is also high and / or large conductor cross-sections are required. Overall, such main supply lines require a large amount of installation space.

[0007] To reduce disruptive magnetic fields and improve EMC (electromagnetic compatibility), it is known to stack the busbars of the forward conductor / supply conductor and the return conductor / ground conductor in layers. Such a stacked arrangement can be found, for example, in DE 10 2015 220 115 B4. The ground conductor rests on a body component and is surrounded by insulation. In one design variant, the ground conductor and the body component are coated together with a layer of paint.

[0008] Based on this, the invention is based on the object of enabling an electrical power supply in a motor vehicle that has good EMC properties with a small installation space requirement and with good thermal properties.

[0009] The object is achieved according to the invention by a device for electrical power distribution in a vehicle with a stacked busbar arrangement, as well as by such a busbar arrangement. The advantages and preferred embodiments specified below with regard to the device are analogously applicable to the busbar arrangement.

[0010] The busbar arrangement comprises a supply conductor and a ground conductor as busbars, each designed as a flat conductor and abutting against one another with their flat sides. The device further comprises a body component along which the busbar arrangement is guided. The ground conductor is designed as a bare metal conductor and without insulation, at least in the areas where it abuts the supply conductor. The flat conductor is therefore free of insulation, at least on its (upper) flat side. The conductor material, i.e. the metal, is therefore exposed at least on the upper flat side and is not protected by insulation.

[0011] In contrast, the supply conductor has an insulating sheath that completely surrounds the actual metallic and solid conductor. This insulating sheath electrically insulates the supply conductor and the ground conductor from each other. The bare ground conductor lies directly against this insulating sheath. The insulating sheath is designed, in particular, as an extruded insulating sheath that is extruded onto the supply conductor. The insulating sheath preferably has a constant thickness over its entire circumference and preferably also over its entire length.

[0012] This design with the stacked busbar arrangement with the two flat conductors initially achieves the desired good EMC properties. By omitting electrical insulation, several positive properties are achieved at the same time. Firstly, omitting insulation leads to material and therefore cost savings. At the same time, this omission is also accompanied by a reduction in the required installation space. Finally, at least in variants where the bare conductor is in direct contact with a heat sink such as the body component, this omission also leads to improved cooling of the return conductor, as the heat can be dissipated more effectively. In contrast, electrical insulation typically leads to thermal insulation, which only allows reduced heat dissipation.The improved thermal properties in turn allow a reduction in the conductor cross-section, which also leads to a smaller installation space requirement and lower costs.

[0013] Another particular advantage is that by omitting insulation on the upper flat side, the ground conductor moves closer to the supply conductor, thereby improving the EMC properties.

[0014] Overall, this results in improved EMC properties, reduced installation space requirements and improved cooling.

[0015] Preferably, the busbar arrangement has only two conductor layers, namely the supply conductor and the ground conductor. Each layer is formed by a monolithic, single-layer conductor rail.

[0016] The ground conductor usually rests directly on the body component. Preferably, it is also designed as a bare metal conductor without insulation, at least in these areas. The flat conductor is therefore also designed without (its own) insulation on its lower flat side, where it rests on the body component, and rests as a bare metal rail. This creates direct surface contact between the flat side of the ground conductor and the body component. This keeps the installation height low and also has a positive effect on cooling.

[0017] In particular, the ground conductor, at least in the sections with which it is in contact with both the supply conductor and the body component, is completely without insulation and is therefore free of its own insulation.

[0018] Specifically, its flat side facing away from the supply conductor, as well as its two opposite narrow sides, are bare metal surfaces without insulation. Only in relation to the supply conductor is an insulating layer adjacent to one (bare) flat side of the ground conductor—due to its insulation.

[0019] Preferably, the ground conductor is uninsulated along its entire length. It is therefore a bare metal bar along its entire length.

[0020] The busbar arrangement is, in particular, a main supply line, a so-called backbone of a motor vehicle electrical system, as mentioned and defined at the beginning. The busbar arrangement typically extends from a front part of the vehicle to a rear part of the vehicle. The length of the busbar arrangement is typically greater than 1 m, preferably greater than 1.5 m or even greater than 2 m. It is designed to transmit high currents of at least several 10 A, typically more than 100 A. When flat conductors are mentioned here, this means a solid metal rail with a rectangular cross-sectional profile which - in the case of the supply conductor - is surrounded by the insulating sheath.

[0021] In a preferred embodiment, the body component is electrically conductive and the ground conductor rests on the body component, with no electrical insulation being formed between the return conductor and the body component. The bare ground conductor therefore rests on the bare body component. This creates both an electrical connection between the ground conductor and the body component and a good thermal connection, so that a particularly good additional cooling effect is achieved. The ground conductor preferably rests on the body component over at least a large part of its length, for example at least over 50%, at least over 80% or even at least over 90% of its length. In particular, it rests fully on the body component with one of its flat sides.

[0022] Due to the improved heat dissipation, the thermal load during operation is reduced compared to a variant with an insulated flat conductor. This also results in improved cooling of the entire busbar arrangement. Compared to a conventional variant with an insulated ground conductor, the conductor cross-section of the supply conductor and / or the ground conductor can therefore be reduced. In particular, the thermal load is reduced compared to the supply conductor surrounded by the insulating sheath. Due to this reduced thermal load, the conductor cross-section of the ground conductor in particular can be reduced, particularly compared to the supply conductor. In a preferred embodiment, the cross-sectional area of ​​the ground conductor is therefore also smaller than that of the supply conductor.

[0023] In a preferred embodiment, the ground conductor is electrically connected to the body component via an additional contact element. The contact element is designed, in particular, as a laterally protruding contact element, specifically as a laterally protruding contact tab. This additional contact element achieves a defined and reliable electrical contact connection between the ground conductor and the body component, regardless of the fact that, in the preferred embodiment, the bare ground conductor rests on the bare body component.

[0024] The contact element is preferably generally a screw contact element so that the ground conductor and the body component can be screwed together.

[0025] Two electrical components are usually connected to one another via the busbar arrangement, so that a power and energy supply can be established. Connection terminals are typically formed at the ends of the busbar arrangement, for example cable lugs, connection bolts or connecting cables, to which a contact element, e.g. a cable lug, is optionally arranged. The two flat conductors are designed as stacked and layered flat conductors over the entire length, or at least over almost the entire length (at least 90%) between the two ends / connection terminals. The layered arrangement can only be dissolved in the connection area and thus in the area of ​​the components to be connected.

[0026] According to a preferred embodiment, the ground conductor is routed at least at one of its two ends only as far as the component connected to the supply conductor there, and is electrically connected to the body component at this end, in particular via the contact element, without, however, being electrically connected to the component. Therefore, a separate connection terminal and separate contacting of the ground conductor to the electrical component are omitted. The electrical component therefore has no contact element or connection terminals for the direct electrical and mechanical connection of the ground conductor. The required ground connection can be established in another way, for example, via another contact connection to the body component.This design is based on the consideration that, on the one hand, a current path via the body component is fundamentally possible and sufficient for the ground connection, but that the stacked arrangement of the flat conductors achieves the advantage of good EMC properties, so that, for example, no or at most only minimal exposure to magnetic or electromagnetic fields is to be feared within the passenger compartment. In this design, the ground conductor is therefore preferably shorter at one end than the supply conductor, i.e. ends before it. In particular, the ground conductor - unlike the supply conductor - does not have a connection terminal for connecting to the component at this end. On the opposite end, the ground conductor preferably has a connection terminal.

[0027] Alternatively, in addition to being connected to the body component via the contact element, the ground conductor is also connected directly to the component via a connection terminal.

[0028] In a preferred embodiment, the busbar arrangement and at least the ground conductor are mechanically attached to the body component at at least several attachment points. According to a first embodiment, no electrical contact is made between the ground conductor and the body component at the attachment points. Alternatively, an electrical connection between the ground conductor and the body component is also established via the attachment points. In the latter case, therefore, at least several of the previously described contact elements are provided.

[0029] The fastening is typically done via a screw connection or clips. Adhesive fastening is also possible, for example, using adhesive or adhesive tape, which are electrically conductive, for example.

[0030] In one design variant, for example, the ground conductor is welded to the body component, for example along the outer longitudinal edges of the ground conductor.

[0031] In a preferred embodiment, the two flat conductors are held together along their length by means of several connecting elements, such as hook-and-loop fasteners, clips, or the like. The two flat conductors are attached to the body component, particularly in the area of ​​these connecting elements. The connecting elements are therefore specifically designed as fastening elements and thus perform a dual function. The connecting elements are preferably made of an electrically insulating material such as plastic.

[0032] According to a preferred embodiment, the body component is part of a passenger compartment and is, in particular, a body floor of the passenger compartment. The busbar arrangement is arranged on the side of the body component facing the passenger compartment. The busbar arrangement with the bare ground conductor therefore runs within the passenger compartment, protected from environmental influences.

[0033] The body component is preferably a battery cover for a traction battery. The motor vehicle is therefore an electric motor-driven vehicle, for example a hybrid vehicle or a purely electric vehicle. The traction battery provides the energy required for the electric motor drive of the motor vehicle. Such traction batteries are typically located beneath the vehicle floor. The entire traction battery, which typically consists of a plurality of individual, suitably interconnected battery modules, is closed off at the top by a battery cover. This battery cover is often also used as the vehicle floor and is thus part of the load-bearing vehicle body.This battery cover is, in particular, a metal cover, preferably made of bare metal, for example, aluminum, and thus without any insulation or coating. The bare ground wire is therefore routed on the bare battery cover.

[0034] The power and energy supply device described here, with its two stacked flat conductors, is generally part of a motor vehicle electrical system. It is preferably part of a low-voltage electrical system with an on-board voltage of less than 60 V, for example, with an on-board voltage of 12 V or 48 V. Especially at these low voltages, no special additional measures are required for occupant protection. The necessary electrical insulation for contact protection is provided by the trim panels typically present inside the passenger compartment.

[0035] The interconnected components are generally loads, power distributors, a fuse box, a battery, an inverter, or a DC / DC converter. Preferably, a power source is connected at least indirectly to a load via the busbar arrangement. The power source is, in particular, a battery or a generator.

[0036] Specifically, a vehicle battery, and in particular a DC / DC converter, is connected to a consumer or a power distributor via the busbar assembly. The DC / DC converter transforms the voltage of the (traction) battery, typically a high-voltage battery, to the desired low-voltage vehicle electrical system voltage. The busbar assembly is generally a prefabricated assembly unit that simply needs to be installed in the vehicle. This assembly unit comprises the two stacked flat conductors, with the ground conductor—in its pre-assembled state (immediately) before its installation on the body component—being a bare metal conductor and free of insulation.

[0037] The prefabricated unit further comprises one or more, and preferably all, of the following and previously described elements:

[0038] The at least and preferably exactly one contact element for the electrical and mechanical connection of the ground conductor to the body component;

[0039] - connecting elements for connecting and holding the two flat conductors together, which are preferably also designed as fastening elements;

[0040] - Connection terminals for connecting to the components to be connected.

[0041] Furthermore, the busbar arrangement is preferably adapted to the contour and shape of the body component, i.e., it is designed and, in particular, curved in sections, so that it rests flat against the body component over its entire length. This is especially true if the body component is not flat but rather has a three-dimensional contour, so that the ground conductor can rest against this three-dimensional component.

[0042] An embodiment of the invention is explained in more detail below with reference to the figures, which show, in some cases highly simplified representations:

[0043] FIG 1 shows a representation of a motor vehicle,

[0044] FIG 2 shows a cross-sectional view of a busbar arrangement with a bare ground conductor resting on a bare body component, and FIG 3 shows a partial side view of a device for electrical power supply with a busbar arrangement shown in FIG 2.

[0045] A motor vehicle 2 shown in FIG. 1 has a busbar arrangement 4 as part of a device for supplying electrical power within the motor vehicle 2. The busbar arrangement 4 connects two electrical components, in the exemplary embodiment a DC / DC converter 6 with a power distributor 8. The busbar arrangement 4 is installed on a battery cover as a body component 10. The battery cover is part of a traction battery 12 (not shown in detail here). The battery cover also forms an underbody of a passenger compartment (not shown in detail here).

[0046] At one end side, in the exemplary embodiment the end side directed towards the converter 6, the busbar arrangement 4 has line pieces as connection terminals 14, which connect the busbar arrangement 4, namely on the one hand a supply conductor 16 and on the other hand a ground conductor 18 (see also FIGS. 2 and 3) with suitable contact connections of the converter 6.

[0047] On the opposite end of the busbar arrangement 4, in this embodiment, the power distributor 8, the supply conductor 16 is connected, preferably directly, to a power distributor 20, for example, a distribution plate. From this, several supply lines 22, each protected by fuse elements, branch off, particularly with different conductor cross-sections, to then lead to consumers (not shown in detail here) and supply them with power.

[0048] FIG. 1 also shows a contact element 24, which is formed directly in the area of ​​the power distributor 8 and which serves for electrical contact as well as for the mechanical fastening of the ground conductor 18 to the body component 10. Furthermore, distributed along the length of the busbar arrangement 4, a plurality of connecting elements 26 are shown, via which the two flat conductors, i.e. the supply conductor 16 and the ground conductor 18, are held together and via which a fastening to the body component 10 is also carried out. In this case, preferably only a mechanical fastening is carried out, without an electrical connection of the ground conductor 18 to the body component 10.

[0049] Both the supply conductor 16 and the ground conductor 18 are flat conductors, i.e., metal bars with a rectangular cross-sectional profile. As can be seen particularly from FIG 2, the ground conductor 18 is designed as a bare metal conductor, which therefore has no insulation of its own around its circumference. In contrast, the supply conductor 16 has insulation 28 that surrounds the supply conductor 16 around its circumference in the manner of an insulating sheath. The insulating sheath is preferably designed as a sheath extruded onto the supply conductor 16. The insulating sheath generally has a constant thickness over its circumference and, in particular, over its entire length. Only at its end sides is the supply conductor 16 free of insulation 28 in order to enable the electrical connection there. Conversely, the ground conductor 18 is free of any insulation over its entire length.Insulation to the supply conductor 16 is provided via the insulation 28 of the supply conductor 16. Therefore, if it is stated here that the ground conductor 18 is free of insulation, this is understood to mean that the ground conductor 18 does not have its own insulation, i.e., no insulation that completely surrounds it in the manner of a sheath.

[0050] In the prefabricated unit, which represents the busbar arrangement 4 before its installation in the motor vehicle, the flat side opposite the supply conductor 16 and the two opposite lateral narrow sides are therefore present as bare metal surfaces to which no insulation is applied.

[0051] In the embodiment of FIG. 2, it is further provided that a conductor cross-section of the ground conductor 18 is smaller than a conductor cross-section of the supply conductor 16. For this purpose, either the width and / or the height of the ground conductor 18 is reduced compared to the supply conductor 16. If only the width or only the height is reduced, the extension in the other direction (i.e., height or width) is preferably identical to that of the supply conductor 18.

[0052] The side view of FIG. 3 shows a variant in which, on one end, connecting bolts, specifically screw bolts, are attached, in particular welded, to the two flat conductors 16, 18 as connection terminals 14. At the opposite end, the supply conductor 16 is inserted via a housing nozzle into the housing of the connected component, specifically the described power distributor 8. The electrical connection is made inside, for example, via the power distributor 20 described in FIG. 1.

[0053] FIG. 3 also shows an exemplary embodiment in which the ground conductor 16 is routed only to immediately before the component connected via the supply conductor 16, in this case the power distributor 8, without direct electrical contact being made with the power distributor 8. Any necessary ground contact is made, for example, directly via a suitable ground connection element with the body component 10.

[0054] The invention is not limited to the exemplary embodiment described above. Rather, other variants of the invention can also be derived therefrom by those skilled in the art without departing from the scope of the invention. In particular, all individual features described in connection with the exemplary embodiment can also be combined with one another in other ways without departing from the scope of the invention.

[0055] List of reference symbols

[0056] 2 motor vehicles

[0057] 4 Busbar arrangement 6 DC / DC converter

[0058] 8 power distributors

[0059] 10 body component

[0060] 12 Traction battery

[0061] 14 Connection terminal 16 Supply conductor

[0062] 18 ground conductors

[0063] 20 power distributors

[0064] 22 supply lines

[0065] 24 Contact element 26 Connecting element

[0066] 28 Insulation

Claims

Claims: Device for electrical power distribution in a vehicle comprising a stacked busbar arrangement (4) with a supply conductor (16) and a ground conductor (18) which are in contact with each other and are designed as flat conductors, and with a body shell along which the busbar arrangement (4) is guided, characterized in that the ground conductor (18) is in contact with the supply conductor (16) at least in the area where it is formed as a bare metal conductor. Device according to claim 1, characterized in that the ground conductor (18) is in contact with the body shell component (10) and is also designed as a bare metal conductor in the area where it is in contact with the body shell component (10). Device according to one of the preceding claims, characterized in that the body shell component (10) is electrically conductive and the ground conductor (18) rests on the body shell component (10), wherein no electrical connection is formed between the ground conductor (18) and the body shell component (10).Device according to one of the preceding claims, characterized in that the ground conductor (18) has a smaller cross-sectional supply conductor (16). Device according to one of the preceding claims, characterized in that the ground conductor (18) is electrically connected via a contact element (2- body component (10)). Device according to the preceding claim, characterized in that... A device according to one of the two preceding claims, characterized in that the busbar assembly (4) connects two electrical components, wherein the ground conductor (18) extends at least at one end only as far as the component connected there to the supply conductor (16) and is electrically connected at this end to the body component (10) via the contact element (24), without being electrically connected to the component. A device according to one of the preceding claims, characterized in that the busbar assembly (4) is attached to the body component (10) at least at several attachment points. A device according to one of the preceding claims, characterized in that the two flat conductors are held together by connecting elements (26), in particular hook-and-loop fasteners or clips, and are attached to the body component (10) in particular in the area of ​​the connecting elements (26).Device according to one of the preceding claims, characterized in that the body component (10) is part of a passenger compartment, in particular a body floor of the passenger compartment, wherein the busbar arrangement (4) is mounted on the side of the body component (10) oriented towards the passenger compartment. Device according to one of the preceding claims, characterized in that the body component (10) is a battery cover of a traction battery (12). Device according to one of the preceding claims, characterized in that it is part of a low-voltage electrical system with an electrical system voltage of less than 60 V. Device according to one of the preceding claims, characterized in that the busbar arrangement (4) is a vehicle battery. in particular connects a DC / DC converter (6) to a load or a power distributor (8). Busbar arrangement (4) for a vehicle with a device according to one of the preceding claims, which has two stacked flat conductors, namely a supply conductor (16) and a ground conductor (18), wherein the ground conductor (18) is designed as a bare metal conductor without insulation, at least in the areas where it is in contact with the supply conductor (16). Busbar arrangement according to the preceding claim, characterized in that the ground conductor (18) is designed entirely as a bare metal conductor and the flat side opposite the supply conductor (16) as well as the narrow edges are bare metal surfaces. Busbar arrangement according to the preceding claim, characterized in that the supply conductor (16) has an insulation (28), in particular an extruded insulation, with a constant thickness around its circumference.

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