Electrical AC system of a motor vehicle

Abstract

An alternating current electrical arrangement (11) of a motor vehicle, comprising two electrical components (12, 13) connected via at least one busbar (1, 1', 1''), wherein the busbar (1, 1', 1'') is received in a housing (20) and sealed in a partial area of ​​the passage through the housing (20), wherein the busbar (1, 1', 1'') has rounded edges (2) in the sealed partial area, characterized in that the busbar (1, 1', 1'') is a flat conductor and the rounded edges (2) are provided in the transition between the broad and narrow sides of the flat conductor.

Description

[0001] The invention relates to an electrical alternating current arrangement of a motor vehicle, comprising two electrical components connected via at least one busbar, wherein the busbar is received in a housing and sealed in a partial area of ​​the passage through the housing.

[0002] Modern motor vehicles with partially or fully electric drive systems have one or more such alternating current electrical arrangements, comprising two electrical components electrically coupled via one or, more commonly, several busbars. For example, such an alternating current electrical arrangement includes power electronics and an electric motor that drives the vehicle, coupled via the busbar(s), or a charging device and an energy storage device, where an external charging cable can be connected to the charging device so that the energy storage device, coupled via the busbar(s), can be charged.

[0003] A detailed description of an electric drive can be found in an article in the journal ATZ, 63rd year, 05 / 20, 6, pages 360-365, by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, entitled: Highly Integrated and Flexible Electric Drive Unit for E-Vehicles. This article describes a drive unit for a vehicle axle, comprising an electric motor arranged concentrically to a bevel gear differential. Such drive units are also referred to as e-axles.

[0004] A busbar is typically a conductor, usually rectangular in cross-section, made of copper, for example, which has a geometry corresponding to the given installation space and is connected to the electrical components via appropriate connection interfaces.

[0005] Publications DE 20 2022 101 493 U1 and DE 10 2014 216 765 A1 already disclose sealed busbars arranged in a housing. German patent application DE 10 2016 100 389 A1 discloses an electric drive system comprising an electric machine and a pulse inverter, which is connected to the electric machine via busbars arranged in a busbar housing.

[0006] In the development of electric motors intended for e-axles or hybrid modules, there is a continuing need to increase their power densities, making the cooling of these electric motors increasingly important. Due to the required cooling capacity, hydraulic fluids, such as cooling oils, have become the standard in most designs for dissipating heat from the thermally stressed areas of an electric motor.

[0007] In this context, so-called direct slot cooling and winding head cooling systems have become known. These systems use a liquid cooling medium flowing directly into the slots to achieve very effective cooling of the electrical conductors, as well as good heat dissipation from the winding heads by applying the cooling medium to them. For this to work, it is generally necessary to enclose the winding heads to accommodate the cooling medium. The corresponding high-voltage connections must also be routed through this enclosure.

[0008] The invention is based on the problem of providing an improved electrical alternating current arrangement.

[0009] To solve this problem, in an AC electrical arrangement of a motor vehicle comprising two electrical components connected via at least one busbar, wherein the busbar is enclosed in a housing and sealed in a portion of its passage through the housing, the busbar is provided with rounded edges in the sealed portion. The busbar itself is a flat conductor, i.e., it has a rectangular cross-section, with its width typically being a multiple of its thickness. The rounded edges are located in the transition area between the broad and narrow sides of the flat conductor.

[0010] The alternating current arrangement according to the invention is characterized by the removal of sharp edges from the busbars, which are usually manufactured by stamping. Sharp edges are more difficult to seal and there is a risk that the sealing effect will not be permanent.

[0011] According to a first embodiment of the invention, the rounded edges are produced by melting. This eliminates the need for relatively expensive machining to round the edges. Furthermore, melting the edges to round them does not produce any chips that could contaminate the electrical AC circuitry.

[0012] Melting is preferably carried out using a laser. This allows the edge to be processed particularly precisely and selectively compared to other thermal methods such as heating with a gas flame, without affecting unwanted areas.

[0013] In one embodiment of the AC electrical arrangement, the portion of the passage through the housing is sealed by means of an O-ring, a molded seal, or a potting compound. This allows the housing to remain liquid-tight despite the busbar passing through, reliably sealing off areas exposed to the cooling medium, such as the winding head and / or the stator of the electric motor.

[0014] In addition to the alternating current electrical arrangement, the invention further relates to a motor vehicle comprising at least one such alternating current electrical arrangement.

[0015] The AC electrical arrangement can comprise power electronics and an electric machine connected via at least one busbar as modular units. Alternatively, the AC arrangement can also comprise a charging connection device and an energy storage device connected via at least one busbar as modular units.

[0016] The invention is explained below with reference to exemplary embodiments and the drawings. The drawings are schematic representations and show: Fig. 1 a schematic representation of various busbars to be used for an electrical alternating current arrangement according to the invention, Fig. 2 A schematic representation of the production of the rounded edges of a busbar to be used for an electrical AC arrangement according to the invention in an embodiment according to Fig. 1b, Fig. 3 a schematic representation of a busbar to be used for an electrical alternating current arrangement according to the invention Fig. 2 after melting the edges, Fig. 4 a schematic representation of a busbar arranged in a housing for use in an electrical alternating current arrangement according to the invention;

[0017] The Fig. Figure 1 shows various embodiments of a busbar 1, 1' and 1'' for an alternating current electrical arrangement 11 according to the invention. The busbars 1, 1' and 1'' basically consist of bodies 3, 4, 5, 6, 7 and 8, which are stamped and / or cold-formed from a sheet with a rectangular cross-section. The material is usually copper due to its high conductivity; the busbars 1, 1', 1'' are designed as flat conductors. The busbar 1 is shown as consisting of only one uniform body 3. The busbar 1' consists of two bodies 4, 5, which differ only in their cross-section; the body 5 has a smaller cross-section. The busbar 1" consists of three bodies 6, 7, 8, where bodies 6 and 8 have the same cross-section and the body 7, located between them, has a smaller cross-section. Each body 3, 4, 5, 6, 7, 8 has a rectangular cross-section and is essentially designed like a flat conductor.Each 1, 1', 1'' busbar can have almost any shape, depending on the available installation space; a busbar can also consist of two bodies arranged at an angle to each other. It should also be noted that 1, 1', 1'' busbars, and any angled busbars, are usually stamped, formed, and possibly bent from a single sheet of metal.

[0018] After stamping, the individual bodies 3, 4, 5, 6, 7 and 8 have sharp edges 2 which may damage any seal or, in the case of potting or overmolding, may not reliably ensure a tight, permanent seal of the sealing material.

[0019] In Fig. Figure 2 shows the busbar 1' consisting of bodies 4 and 5. A laser beam 90, emitted from a laser 9, is directed at the edges 2 of body 5. The laser beam 90 heats the material of the edges 2 such that it melts near the surface and solidifies again after the laser is switched off. Since liquids form droplets, the melt creates a rounded shape, as is the case with the edges 2, as shown in Figure 2. Fig. Figure 3 illustrates this case. The resulting cross-section of body 5 in the laser processing area can be seen in section AA. It is also not necessary for the laser processing to extend over the entire length of edges 2; the rounding is only required in the area of ​​a planned seal.

[0020] Fig.Figure 4 shows an embodiment of an electrical AC arrangement 11 according to the invention, comprising two schematically depicted electrical components 12, 13, which can be, for example, power electronics on the one hand and an electric machine on the other, or a connection device to which an external charging plug can be connected, and an energy storage device. The two components 12, 13 are electrically connected to each other via one or more busbars 1' according to the invention. Of course, busbars according to one of the previously described embodiments can also be used.

[0021] In this embodiment, the busbar 1' is arranged within a housing 20 and extends through it such that the ends of the busbar protrude on both sides of the housing 12 for connection with electrical components 12, 13. An O-ring 15 is provided, which is located in the area of ​​the rounded edges 2 and seals the busbar 1' against the housing 20. The O-ring 15 prevents the passage of a liquid medium through the housing 20. Such a liquid medium, typically a hydraulic fluid, is used, for example, to cool one of the electrical components 13, in particular a stator of an electric motor. Contamination with the liquid medium of the other electrical component 12, for example an inverter, can be effectively prevented by the electrical AC arrangement 11 according to the invention. Reference symbol list 1, 1', 1'' Busbar 2 edge 3 bodies 4 bodies 5 bodies 6 bodies 7 bodies 8 bodies 9 lasers 90 laser beam 10 Connection element 11 AC arrangement 12 electrical component 13 electrical component AA cut 15 O-ring 20 cases

Claims

[1] Alternating current electrical arrangement (11) of a motor vehicle, comprising two electrical components (12, 13) connected via at least one busbar (1, 1', 1''), wherein the busbar (1, 1', 1'') is received in a housing (20) and sealed in a partial area of ​​the passage through the housing (20), wherein the busbar (1, 1', 1'') has rounded edges (2) in the sealed partial area, characterized by , that the busbar (1, 1', 1'') is a flat conductor and the rounded edges (2) are provided at the transition between the wide and narrow sides of the flat conductor. [2] Alternating current electrical arrangement (11) according to claim 1, characterized by , that the rounded edges (2) are produced by melting. [3] Alternating current electrical arrangement (11) according to claim 2, characterized by , that the melting is carried out using a laser (9). [4] Alternating current electrical arrangement (11) according to any one of the preceding claims, characterized by, that the portion of the passage through the housing (20) is sealed by means of an O-ring (15), a molded seal or a potting. [5] Motor vehicle comprising at least one alternating current electrical arrangement (11) according to any one of the preceding claims.

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