COAXIAL CABLE

Description

AREA OF INVENTION

[0001] The invention relates to a coaxial cable for the transmission of electric current in a high-voltage system of a motor vehicle comprising an inner conductor comprising a plurality of individual wires; an outer conductor comprising a plurality of individual wires; an inner insulating layer arranged between the inner and outer conductors; and an insulating cable sheath; wherein the outer conductor is designed to transmit between 50% and 150% of the electrical power that can be transmitted by the inner conductor, and the use of such a cable in a high-voltage system of a motor vehicle with an electric drive.

[0002] In automotive engineering, high-voltage systems, also known as high voltage or HV for short, are systems that operate with alternating voltages above 30 V up to 1 kV or with direct voltages above 60 V up to 1.5 kV. Such high-voltage systems are found particularly in vehicles with an electric drive, such as electric vehicles, hybrid vehicles, or vehicles with fuel cells.

[0003] Coaxial cables are generally understood to be cables with a cable structure consisting of an inner conductor and at least one outer conductor surrounding the inner conductor in cross-section, with an inner insulating layer providing electrical isolation between the inner conductor and the outer conductor. Furthermore, cables generally also include an insulating cable jacket, which preferably forms the outermost layer of the cable, insulates the interior of the cable from the environment, and is usually made of a plastic or an elastomer. STATE OF THE ART

[0004] In high-voltage systems, cables are typically used to electrically connect the electrical components. These cables have two parallel conductors. Each conductor has a corresponding first insulating layer, also called conductor insulation, with the electrical conductor within the insulation usually being stranded. The two conductors are surrounded by an insulating sheath, which is made of a dielectric material, typically a cross-linked plastic or an elastomer. The sheath usually forms the outer insulating layer of the cable. Electrically conductive materials, especially metals such as copper or aluminum, or alloys containing these metals, are suitable for the electrical conductor, particularly the inner conductor.

[0005] For example, DE 10 2014 010 346 B3 also discloses a DC cable designed as a coaxial cable for a high-voltage electrical system of a motor vehicle, wherein in the cross-section the wire conductors of one cable arrangement are arranged in a ring shape around the wire conductors of the other cable arrangement.

[0006] One disadvantage of state-of-the-art cables is that contacting the outer conductor is difficult and requires separating it from the inner conductor. Furthermore, especially with large nominal cross-sections, disadvantages arise regarding the dissipation of heat generated in the inner conductor during operation, as well as in terms of the ease of cable installation. TASK OF INVENTION

[0007] It is therefore an object of the invention to overcome the disadvantages of the prior art and to propose a coaxial cable that enables simplified contacting of the outer conductor. Furthermore, the properties required for laying the coaxial cable are to be improved, and preferably, improved heat dissipation from the inner conductor is to be achieved. A further object of the invention is to propose such a cable design that is cost-effective and economical to manufacture. PRESENTATION OF THE INVENTION

[0008] This problem is solved in a coaxial cable according to the invention of the type mentioned at the outset by the characterizing features of claim 1.

[0009] While in conventional coaxial cables the inner conductor and the ring-shaped outer conductor are arranged coaxially, with the cable axis thus forming the axis of symmetry of the inner and outer conductors, in the coaxial cable according to the invention the inner conductor is arranged eccentrically to the cable axis, which runs through a center point of the cross-section. This eccentric arrangement of the inner conductor is achieved by dividing the individual wires of the outer conductor into at least three separate sector bundles, which are dimensioned such that a conductor axis of the inner conductor arranged inside the sector bundles is offset from the cable axis. Such a dimensioning according to the invention can be achieved, for example, by varying the number of individual wires and / or the number of layers of individual wires in the radial direction, whereby the diameters of the individual wires of the sector bundles are varied.These dimensions vary for three or more of the at least three sector bundles. If several layers of individual wires are provided within a sector bundle, the number of individual wires per layer can also vary. Depending on the relative position of a sector bundle with respect to the cross-section and the total number of sector bundles, different sector bundles can also have the same structure.

[0010] It goes without saying that the individual wires of the inner conductor and / or the outer conductor can also be designed as strands. For example, sector bundles can consist of strands, each of which in turn comprises a plurality of individual wires.

[0011] In other words, the sector bundles are designed to occupy different proportions of the outer conductor's cross-sectional area. For example, a sector bundle located in the area of ​​smallest distance between the inner conductor and the cable sheath can occupy the smallest proportion of the cross-sectional area, while a sector bundle located in the area of ​​greatest distance between the inner conductor and the cable sheath can occupy the largest proportion of the cross-sectional area.

[0012] Preferably, an outer surface of the inner insulation layer of the inner conductor rests against the inner surfaces of the sector bundles, i.e., against the radially inner surfaces of the sector bundles. Accordingly, the design of the inner surfaces of the sector bundles can be used, in particular, to dimension the sector bundles for achieving the eccentricity.

[0013] A coaxial cable with an eccentric inner conductor is particularly easy to manufacture if the insulated inner conductor is stranded with the sector bundles. In other words, the sector bundles are wound around the insulated inner conductor using a stranding machine and / or corresponding components of a stranding system, whereby the stranding process also moves the center of the eccentrically oriented inner conductor along a helical path relative to the cable axis. In other words, the position of the inner conductor in cross-section, relative to the cable axis, changes from one cross-sectional plane to the next. Therefore, another embodiment of the invention provides that the inner conductor and the sector bundles of the outer conductor are stranded together.

[0014] The eccentric orientation of the inner conductor allows for particularly easy separation of the outer conductor in the exposed end section of the coaxial cable, as the outer conductor can be split in the sector bundle that runs along the area of ​​maximum eccentric deflection of the inner conductor and thus offers the least resistance. The separated outer conductor can then be bundled, for example, in a stranded connection section.

[0015] Furthermore, the eccentricity of the inner conductor ensures easier heat dissipation from the inner conductor.

[0016] Finally, the eccentric orientation of the inner conductor and the use of sector bundles as outer conductors also reduce the direction-dependent bending resistance, thus making installation easier.

[0017] Another positive effect of the coaxial cable is that additional electromagnetic shielding is not strictly necessary, especially if one of the conductors is designed as the positive conductor and the other conductor as the negative conductor of a DC HV system.

[0018] Another embodiment of the coaxial cable according to the invention provides that the number of individual wires and the diameters of the individual wires in any sector bundle differ from the number of individual wires and the diameters of the individual wires in an adjacent sector bundle. In principle, it is also conceivable that the number of layers of individual wires differs, although, particularly for manufacturing purposes, it has proven advantageous if the number of layers is the same. The different number of individual wires and the different diameters of the individual wires in adjacent sector bundles make it particularly easy to adjust the eccentricity of the inner conductor.For example, a sector bundle running in the area of ​​smallest distance between the inner conductor and the cable sheath can comprise a larger number of individual wires with smaller diameters than the radially adjoining sector bundle.

[0019] It is particularly preferred that the number of individual wires and the diameters of the individual wires of the sector bundles are selected depending on the position of the respective sector bundle relative to the eccentricity of the inner conductor.

[0020] Advantageously, the number of sector bundles is even, preferably four, six, eight, or ten, although—depending on the diameter of the coaxial cable—more sector bundles are also conceivable. This allows for a simpler geometric design of the coaxial cable's cross-section. The stranding of the inner conductor and sector bundles is also easier to accomplish when the number of sector bundles is even. Therefore, another embodiment of the invention provides that the number of sector bundles is even and that the individual wires of the outer conductor are subdivided into at least four, preferably at least six, or at least eight, sector bundles. A preferred embodiment of the invention provides that exactly four sector bundles are provided.

[0021] In a further embodiment of the invention, for the simple and reliable production of the eccentricity, the sector bundles are designed as opposing and corresponding pairs of sector bundles within the cross-sectional area, wherein the nominal cross-section of any given pair of sector bundles lies between 25% and 175%, preferably between 50% and 150%, and particularly between 75% and 125%, of the average nominal cross-section of all pairs of sector bundles. The nominal cross-section of a sector bundle is understood to be the sum of the cross-sectional areas of the individual wires of the sector bundle, while the nominal cross-section of the pair of sector bundles corresponds to the sum of the nominal cross-sections of the two sector bundles. The average nominal cross-section of all pairs of sector bundles can be calculated as the arithmetic, geometric, or harmonic mean of the nominal cross-sections of all pairs of sector bundles.

[0022] Regardless of the preferred size ratios of the sector bundle pairs to each other, it is advantageous if the sector bundles are subdivided into complementary sector bundle pairs in order to be able to adjust the eccentricity of the inner conductor by dimensioning opposing sector bundles of a sector bundle pair.

[0023] While the design of the inner surfaces of the sector bundles is crucial for the eccentric positioning of the inner conductor within the outer conductor, the outer surfaces of the sector bundles are decisive for the outer shape of the outer conductor. To approximate the outer conductor's enveloping surface as closely as possible to a cylinder, which is advantageous or even necessary for extruding the cable jacket, for example, the sector bundles are dimensioned in another embodiment such that the outer conductor's enveloping surface essentially corresponds to a cylinder with a circular cross-sectional area. This dimensioning can be achieved, analogous to the dimensioning of the sector bundles for the eccentric positioning of the inner conductor, by varying the number of individual wires per sector bundle and / or the number of layers of individual wires in the radial direction per sector bundle and / or the diameters of the individual wires within a sector bundle.Preferably, the aforementioned cylindrical shape of the enveloping surface is achieved by appropriately dimensioning the sector bundles in combination with the stranding.

[0024] To ensure greater flexibility and bendability of the coaxial cable for both small and large nominal cross-sections, another design variant provides that the individual wires of the sector bundles are arranged in single or multiple layers, depending on the nominal cross-section of the outer conductor. For example, the sector bundles are single-layered for small nominal cross-sections and multi-layered for larger nominal cross-sections.

[0025] Another embodiment of the invention provides that a cable foil, a metal foil, or a composite foil is arranged between the outer conductor and the cable sheath. While a metal foil, for example an aluminum foil, and / or a composite foil can also improve the electromagnetic shielding properties of the coaxial cable, a cable foil, particularly made of plastic, can contribute to easier manufacturing and / or removal of the cable sheath on or from the outer conductor.

[0026] A high optical coverage of the outer conductor is particularly advantageous for the electromagnetic shielding properties of the outer conductor and, if necessary, for the most accurate possible approximation of the cylindrical cladding surface. Therefore, a further embodiment of the coaxial cable according to the invention provides that the coverage of the outer conductor is greater than 90%, preferably greater than 95%.

[0027] In high-voltage systems, a particularly high temperature resistance of the cables used is advantageous. To achieve the application-specific temperature resistance, another design variant provides that the cable sheath and / or the inner insulation layer is made of a thermoplastic and / or cross-linked plastic, an elastomer, or a silicone. Silicone in this context refers to silicone-containing plastics, especially those from the poly(organo)siloxane group.

[0028] To ensure that the two conductors, i.e., the inner conductor and the outer conductor, of the coaxial cable can each be connected at one end to the same power source and at the other end to the same current collector, one embodiment of the invention provides that the outer conductor is designed in such a way that it can transmit the same electrical power as the inner conductor.

[0029] Regarding the electrical power to be transmitted by the inner conductor, it should be noted that charging stations for electric vehicles, such as electric cars, are designed for an electrical power output of up to 350 kW, which must be transmitted in the vehicle's high-voltage system when the electric vehicle is connected to the charging station. Of course, it is also conceivable that lower electrical power outputs may be transmitted during operation or the charging process, or that the high-voltage system as a whole is designed for higher or lower maximum power outputs.

[0030] The power transmission between the inner and outer conductors can be coordinated in a particularly simple manner through design measures, especially when the conductors are made of the same materials, and when the nominal cross-section of the spiral conductor is between 75% and 125%, preferably between 90% and 110%, and particularly 100%, of the nominal cross-section of the inner conductor. Advantageously, the nominal cross-section of the inner conductor is between 3 mm² and 95 mm², and particularly between 6 mm² and 60 mm².

[0031] To enable the outer conductor to be easily connected to a power source and / or a current collector and / or a connecting element, as mentioned above, a further embodiment provides that, in a contact state of the coaxial cable, the outer conductor is detached from the inner conductor in an end region of the coaxial cable that has been freed from the cable jacket, and the detached individual wires of the outer conductor are bundled in the form of a stranded connecting section. Through a simple process step, the detached individual wires of the outer conductor can be bundled into a stranded section within this connecting section. The stranded connecting section can then be connected to an electrical terminal like a conventional conductor, thus enabling the simple application of the coaxial cable according to the invention in conventional high-voltage systems.Of course, it is also conceivable that an alternative contacting device is provided, by means of which the coaxial cable can be contacted without prior detachment of the outer conductor.

[0032] The eccentric orientation of the inner conductor allows for particularly easy separation of the outer conductor from the inner conductor by utilizing the locally reduced thickness of the outer conductor. Therefore, a further embodiment of the invention provides that the outer conductor is split in the contact state to create the stranded connection section in the area of ​​maximum eccentric deflection of the inner conductor. This significantly reduces the effort required for deformation and separation.

[0033] As mentioned at the outset, the coaxial cable according to the invention is intended for use in a high-voltage system of a motor vehicle. Motor vehicles with high-voltage systems are characterized by an electric drive, which is either an alternative to an internal combustion engine in a hybrid vehicle or the sole drive in an electric vehicle. Due to its improved flexibility compared to alternative designs and the improved properties of the coaxial cable according to the invention, such a coaxial cable is particularly well suited for use in a high-voltage system of a motor vehicle with an electric drive. Further advantageous uses are defined in dependent claims 13 and 14. BRIEF DESCRIPTION OF THE FIGURES

[0034] The invention will now be explained in more detail using exemplary embodiments. The drawings are exemplary and are intended to illustrate the inventive concept, but in no way to restrict or even exhaustively represent it.

[0035] This shows: Fig. 1 an axonometric view of a first embodiment of a partially exposed coaxial cable; Fig. 2 a side view of the coaxial cable according to Fig. 1 ; Fig. 3 an enlarged cross-section of the coaxial cable according to Fig. 1 Fig. 4 an axonometric view of a second embodiment of a partially exposed coaxial cable; Fig. 5 an enlarged cross-section of the coaxial cable according to Fig. 4 ; Fig. 6 a schematic representation of a coaxial cable in a contact state. WAYS TO IMPLEMENT THE INVENTION

[0036] The Figures 1 to 3 show the construction of a first embodiment and the Figures 4 to 5This document describes the construction of a first embodiment of a coaxial cable 1 according to the invention for use in a high-voltage system of a motor vehicle for the transmission of electric current. Such coaxial cables 1 are typically used to connect power sources, for example, batteries, to current consumers, such as electric drive units, particularly electric motors. The nominal cross-sections of the conductors 2 and 4 of the cable 1 are selected accordingly to be able to transmit the currents and voltages of the high-voltage system. For clarity, the individual sections of the coaxial cable are shown exposed.

[0037] In the Figures 1 and 2It can be seen that the coaxial cable 1 comprises an inner conductor 2 consisting of several individual wires, which is insulated from the surrounding outer conductor 4 by means of an inner insulating layer 3. The outer conductor also comprises several individual wires, which are subdivided into different sector bundles 5 to achieve an eccentric orientation of the inner conductor 2, as will be described in detail below. The coaxial cable 1 further comprises an outer insulating cable jacket 7 made of plastic, which is preferably designed as silicone insulation. Additionally, a foil 8, preferably a metal foil, in particular an aluminum foil, is provided between the outer conductor 4 and the cable jacket 7. This foil improves the properties of the coaxial cable 1 but is not essential for its basic construction.

[0038] The detailed construction of coaxial cable 1 will now be described using the Figure 3As can be clearly seen, the inner conductor 2 in the depicted cross-section, which is oriented normal to a cable axis 9 of the coaxial cable, is positioned eccentrically relative to the cable axis 9. In other words, there is an offset between the cable axis 9 and a conductor axis 6 of the inner conductor 2.

[0039] This offset between conductor axis 6 and cable axis 9 is achieved by dimensioning the sector bundles 5 such that the inner conductor 2 is positioned eccentrically to the cable axis 9 within the cross-sectional area. In detail, the outer conductor 4 in this embodiment is divided into four sector bundles 5: a first sector bundle 5a, which runs in the area of ​​greatest distance between the inner conductor 2 and the cable sheath 7; a third sector bundle 5c, which runs in the area of ​​smallest distance between the inner conductor 2 and the cable sheath 7; and a second sector bundle 5b and a fourth sector bundle 5d, each arranged between the first sector bundle 5a and the third sector bundle 5c.

[0040] By appropriately dimensioning the different sector bundles 5, i.e. by choosing the number of individual wires per sector bundle 5 and the diameter of the individual wires per sector bundle 5, the eccentric offset of the inner conductor 2 can be adjusted, wherein the individual wires of the sector bundles 5 are designed to run in a single layer in the present embodiment.

[0041] In detail, in the present embodiment, the diameter of the individual wires of the first sector bundle 5a is larger than the diameter of the individual wires of the adjacent second sector bundle 5b or the adjacent fourth sector bundle 5d. Considering the third sector bundle 5c, the number of individual wires in the adjacent sector bundles 5b and 5d is smaller, and the diameter of the individual wires in the adjacent sector bundles 5b and 5d is larger than that of the third sector bundle 5c.

[0042] When considering the cross-section, it also becomes apparent that the first sector bundle 5a and the third sector bundle 5c, or the second sector bundle 5b and the fourth sector bundle 5d, each form a sector bundle pair, since the respective sector bundles 5 in the cross-section are opposite each other on the one hand and complement each other on the other hand in order to determine the position of the inner conductor 2.

[0043] As from Figure 3As can be seen, the eccentric positioning of the inner conductor 2 is determined by the design of the surfaces of the sector bundles 5 facing the inner conductor 2. To further ensure that a surface of the outer conductor 4 essentially corresponds to a cylinder with a circular cross-sectional area, which is particularly advantageous or necessary for the application of the cable sheath 7, the individual wires of the sector bundles 5 are also dimensioned or designed such that the outer surfaces of the sector bundles 5 facing the cable sheath 7 exhibit this property.

[0044] In the present embodiment, the sector bundles 5 of the outer conductor 4 are stranded with the inner conductor 2. Due to the stranding process, the position of the inner conductor 2 in the cross-section relative to the cable axis 9 also changes from one section plane to the next. In other words, the eccentric inner conductor 2 runs helically around the cable axis. 9.This "waving motion" of the inner conductor 2 is, for example, in Figure 2 particularly easy to see.

[0045] The Figures 4 and 5 Figure 1 shows a second embodiment of the coaxial cable 1, which has a larger nominal cross-section than the coaxial cable 1 according to the first embodiment. The basic structure of the second embodiment is analogous to the previously described structure, so only the differences will be discussed.

[0046] While the individual wires of the sector bundles 5 of the first embodiment are arranged in a single layer, the individual wires of the sector bundles 5 of the second embodiment are arranged in multiple layers, more precisely in two layers. This allows the diameters of the individual wires to be kept smaller compared to a single-layer design, in order to increase the flexibility of the coaxial cable 1.

[0047] It goes without saying that the same principle could also be applied to more than four sector bundles 5, for example six or eight or more. Likewise, in this case, a correspondingly larger number of complementary sector bundle pairs would also be provided.

[0048] In Figure 6An advantageous design of an end region 10 of a coaxial cable 1 in a contact state is shown, which simplifies the connection of the coaxial cable 1 according to the invention to an electrical connection. In the end region 10 of the cable 1, at least the cable sheath 7 is removed, so that the outer conductor 4 is exposed. Because the outer conductor 4 is helically wound around the inner conductor 2, i.e., stranded, the individual wires of the outer conductor 4 can be easily detached from the inner conductor 2. After the individual wires of the outer conductor 4 have been detached, they are brought together on one side of the inner conductor 2 and bundled in a strand-like connecting section 11.

[0049] By bundling the individual wires of the outer conductor 4 in the stranded connecting section 11, the end area of ​​the cable corresponds to 1,when the inner insulation layers 3 in the end section of the end region 10 are removed and the inner conductor 2 is thus stripped, a cable with two stranded cable connection sections for connection to an electrical terminal, wherein the stripped end section of the inner conductor 2 represents a first cable connection section and the stranded connection section 11 of the outer conductor 4 represents a second cable connection section.

[0050] It is particularly advantageous if, for the purpose of separating the outer conductor 4, the sector bundle 5 is divided which lies in the area of ​​maximum eccentric deflection of the inner conductor 2. In the two exemplary embodiments, the outer conductor would therefore be divided in the area of ​​the third sector bundle 5c.

[0051] The coaxial cable 1 can thus be easily connected to another electrical component, such as a power source or a current collector. This is because, in the stranded connecting section 11, which represents the end section of the outer conductor 4, the individual wires of the outer conductor 4 are transformed into a stranded conductor and bundled together. This stranded connecting section 11 can then be connected to the electrical component in the conventional manner. Since the inner conductor 2 and the stranded connecting section 11 of the coiled conductor 4 can therefore be connected separately and, if necessary, arranged differently relative to each other, the provision of the stranded connecting section 11 in the coaxial cable 1 according to the invention means that there is no longer any significant difference in the contact condition compared to the connection of a conventional two-core cable.In other words, the coaxial cable 1 according to the invention also has two strand-shaped cable connection sections in the contact state, which essentially correspond to the end section of a conventional two-core cable.

[0052] For the reasons mentioned above, the cable 1 according to the invention is particularly suitable for use in high-voltage systems of motor vehicles with electric drive, since it is designed in particular for the transmission of current between a power source and a current consumer, wherein, for example, in a direct current system, the inner conductor 2 connects the positive terminal of the power source to the consumer, while the coiled conductor 4 connects the negative terminal of the power source to the consumer, whereby of course the reverse assignment of the conductors is also conceivable. REFERENCE MARK LIST

[0053] 1 Coaxial cable 2 Inner conductor 2a Inner conductor bundle 3 Inner insulation layer 4 Outer conductor 5 Sector bundle 5a First sector bundle 5b Second sector bundle 5c Third sector bundle 5d Fourth sector bundle 6 Conductor axis 7 Cable sheath 8 Foil 9 Cable axis 10 End section 11 Stranded connection section

Claims

1. A coaxial cable (1) for transmitting electrical current in a high-voltage system of a motor vehicle, comprising - an inner conductor (2) comprising a plurality of wires; - an outer conductor (4) comprising a plurality of wires; - an inner insulation layer (3) arranged between the inner conductor (2) and the outer conductor (4); - and an insulating cable sheath (7); the outer conductor (4) being configured to to transmit between 50% and 150%, preferably between 75% and 125%, particularly preferably 100% + / - 5%, of electrical power that can be transmitted by the inner conductor (2), the wires of the outer conductor (4), in a cross-sectional area of the coaxial cable (1), when viewed normal to a cable axis (9) of the coaxial cable (1), being divided into at least three separate sector bundles (5), the inner conductor (2) and the sector bundles (5) of the outer conductor (4) being twisted together, characterized in that the sector bundles (5) are dimensioned such that a conductor axis (6) of the inner conductor (2) is positioned eccentrically relative to the cable axis (9) in the cross-sectional area, the diameters of the wires of an arbitrary sector bundle (5, 5a) are different from the diameters of the wires of a sector bundle (5, 5b, 5d) adjoining the arbitrary sector bundle (5, 5a).

2. The coaxial cable (1) according to claim 1, characterized in that the number of wires of an arbitrary sector bundle (5, 5a) is different from the number of wires of a sector bundle (5, 5b, 5d) adjoining the arbitrary sector bundle (5, 5a).

3. The coaxial cable (1) according to any one of claims 1 to 2, characterized in that the number of sector bundles is even and the wires of the outer conductor are divided into at least four, preferably at least six or at least eight, sector bundles.

4. The coaxial cable (1) according to claim 3, characterized in that the sector bundles (5) are configured as sector bundle pairs (5a, 5c; 5b, 5d) that are opposite one another within the cross-sectional area and correspond to one another, a nominal cross section of an arbitrary sector bundle pair (5a, 5c; 5b, 5d) being between 25% and 175%, preferably between 50% and 150%, in particular between 75% and 125%, of an average nominal cross section of all the sector bundle pairs (5a, 5c; 5b, 5d).

5. The coaxial cable (1) according to any one of claims 1 to 4, characterized in that the sector bundles (5) are dimensioned such that an enveloping surface of the outer conductor (4) substantially corresponds to a cylinder having a circular cross-sectional area.

6. The coaxial cable (1) according to any one of claims 1 to 5, characterized in that the wires of the sector bundles (5) are arranged in a single layer or multiple layers depending on a nominal cross section of the outer conductor (4).

7. The coaxial cable (1) according to any one of claims 1 to 6, characterized in that a film (8), preferably a cable film, a metal foil, or a composite film, is arranged between the outer conductor (4) and the cable sheath (7).

8. The coaxial cable (1) according to any one of claims 1 to 7, characterized in that a degree of coverage of the outer conductor (4) is greater than 90%, preferably greater than 95%.

9. The coaxial cable (1) according to any one of claims 1 to 8, characterized in that the cable sheath (7) and / or the inner insulation layer (3) are made of a thermoplastic and / or cross-linked plastics material or an elastomer or a silicone.

10. The coaxial cable (1) according to any one of claims 1 to 9, characterized in that the outer conductor (4) is configured such that it can transmit the same electrical power as the inner conductor (1).

11. The coaxial cable (1) according to any one of claims 1 to 10, characterized in that a nominal cross section of the outer conductor (4) is between 75% and 125%, preferably between 90% and 110%, in particular 100%, of a nominal cross section of the inner conductor (2).

12. Use of a coaxial cable (1) according to any one of claims 1 to 11 in a high-voltage system of a motor vehicle comprising an electric drive.

13. The use according to claim 12, characterized in that the outer conductor (4) is detached from the inner conductor (2) in an end region (10) of the coaxial cable (1) from which the cable sheath (7) has been removed, and the detached wires of the outer conductor (4) are bundled up in the form of a stranded connecting portion (11) in order to bring the coaxial cable (1) into a contact state.

14. The use according to claim 13, characterized in that the outer conductor (4), in the contact state, is split in the region of maximum eccentric displacement of the inner conductor (2) to produce the stranded connecting portion (11).