ON-BOARD ELECTRICAL SYSTEM COMPONENT OF A MOTOR VEHICLE

Description

[0001] The invention relates to a vehicle electrical system component for a motor vehicle comprising a chassis support component made of a fiber composite material and comprising two electrical conductors of an electrical power train extending in a longitudinal direction, wherein the conductors are embedded in the support component.

[0002] Such a vehicle electrical system component can be found, for example, in DE 10 2010 007 108 A1. Several conductors, which can be configured differently, are an integral part of a body component. These conductors serve, for example, as ground wires, power supply wires, and data wires.

[0003] From DE 10 2014 005 001 B4 a body part made of a fiber composite material can also be taken, in which an electrical power train, which is designed in the manner of a sandwich or laminate structure, is arranged on an underside of the body part.

[0004] Further body parts made of fiber composite material with attached electrical conductors can be found, for example, in DE 10 2014 213 881 A1 and US 2010 / 0195959 A1.

[0005] WO 2020 / 048736 A1 describes, for example, a structural element forming a frame, made of fiber-reinforced plastic, in which flat conductors are embedded.

[0006] Integrating such a powertrain, also known as the backbone, of a vehicle's electrical system into a fiber-reinforced composite support structure offers the advantage that the plastic of the chassis support structure provides electrical insulation, thus eliminating the need for a separate insulating sheath. Furthermore, no additional fasteners or mounting measures are required for the powertrain on the vehicle.

[0007] At the same time, the integration into the typically high-strength and sometimes brittle material of the fiber-reinforced composite creates additional requirements that must be considered with regard to long-term usability and thus service life. Furthermore, requirements for the assembly and integration of the conductors into the fiber-reinforced composite must also be taken into account to avoid unduly compromising the integrity of the chassis support component. This means that the actual function and properties of the chassis support component, such as high (intrinsic) stiffness, high load-bearing capacity, etc., must be maintained.

[0008] Based on this, the invention aims to provide a vehicle electrical system component with conductors integrated into a chassis support component made of a fiber-reinforced composite material, which is improved with regard to the longest possible service life. Alternatively or additionally, the invention aims to provide such a vehicle electrical system component in which the integrity of the chassis support component is impaired as little as possible.

[0009] The problem is solved according to the invention by a vehicle electrical system component for a motor vehicle according to claim 1, comprising a chassis support component made of a fiber composite material, with two electrical conductors of an electrical power train extending in a longitudinal direction, forming a conductor pair. The conductors of the conductor pair are embedded in the support component and separated by an insulating layer made of an elastomeric material.

[0010] By using an elastomeric material as an intermediate layer between the two conductors, two main technical advantages are achieved. Firstly, the intermediate layer dampens vibrations that occur during vehicle operation. This reduces the mechanical stress on the conductors. Vibrations in vehicle electrical systems often cause problems, such as conductor breakage, loose connections, or unwanted chafing.

[0011] Furthermore, the elastomeric interlayer allows for compensation of the conductor's (intrinsic) movements, especially those resulting from thermal expansion. It is particularly important to consider that the application in question here involves conductors in a (high-)power electrical system, specifically a so-called backbone of a motor vehicle. These conductors therefore provide the primary power supply to components within the vehicle. Typically, the backbone, and thus the electrical system described here, represents a main connection between a front and rear section of the vehicle for the transmission of electrical power. For example, the electrical system connects a (high-)voltage source, such as a battery or generator, to one or more electrical loads.Typically, the power line begins and / or ends at a power distribution unit, from which several consumers are supplied with electrical power.

[0012] The power train is typically designed to transmit currents of several tens of amperes, preferably several hundred amperes. It can be designed and used for different vehicle electrical system voltages, for example, a conventional 12 V system, a 48 V system, or a high-voltage system, such as one with an AC voltage of 30 V or more, or a DC voltage of 60 V or more. Specifically, the power train is also used in electric motor vehicles (electric vehicles) and serves, for example, to supply power to an electric drive motor. When used in a high-voltage electric vehicle, the power train is typically designed for a vehicle electrical system voltage of several hundred volts.

[0013] When referring to a support component made of a fiber-reinforced composite material, this means a generally known component made of a carbon fiber reinforced polymer (CFRP) or glass fiber reinforced polymer (GFRP) composite material, in which the conductors are integrated and embedded in the matrix of the composite material. This means that the matrix of the composite material, i.e., the composite material itself, completely surrounds the two conductors when viewed in cross-section. The matrix consists of a plastic with the fibers embedded within it.

[0014] In this context, "embedding" means that the conductor pair is directly surrounded by the fiber composite material over its entire circumference, as seen in cross-section. The conductors are preferably bare, meaning they are not surrounded by an (additional) insulating sheath.

[0015] When the term chassis support component is used here, it refers to a body component of a motor vehicle, specifically designed to absorb forces. It is a part of the load-bearing body structure or a part of a panel or other support element. Specifically, the chassis support component is a (vehicle) floor, for example, the floor of a passenger compartment. In electric vehicles, the battery storage system is typically located beneath the passenger compartment in a sandwich floor.

[0016] In a preferred further development, the insulating layer consists of a rubber or a thermoplastic elastomer. Such materials are particularly suitable and offer both good electrical insulation properties and good elastic behavior. The hardness of the insulating layer is, for example, in the range of 20 Shore A to 90 Shore A, or—especially in the case of thermoplastic elastomers—somewhat higher, for example in the range of 30 Shore A to 80 Shore D.

[0017] The conductors are flat conductors, in particular solid flat conductors, specifically of the type of busbars or conductor rails.

[0018] The insulating layer arranged between these is designed like an insulating strip, which is positioned and placed between the two flat conductors. In a preferred embodiment, the insulating strip and the flat conductors have the same width. This results in a kind of stacked sandwich structure in which the ribbon-shaped flat conductors alternate with the insulating strip. This stacked sandwich structure is a prefabricated component that is inserted as an insert during the production of the fiber-reinforced composite substrate, for example, during a lamination process. This ensures good integration of the sandwich structure into the component.

[0019] According to a preferred embodiment, the conductors have conductor ends at one and preferably both ends that extend from the support component and form a contact surface outside the support component. This contact surface provides a connection point for further integration into the rest of the vehicle electrical system.

[0020] Preferably, the conductor ends are angled so that they are suitable for leading out of the supporting component and also form the desired contact surfaces. Specifically, they are either U-shaped or Z-shaped. Each has a section extending from the interior of the supporting component to the outside, to which an angled end section is attached, forming the contact surface. This end section is preferably oriented parallel to a top surface of the supporting component.

[0021] The elastomeric insulating layer is also arranged in the outward-leading section between the conductors.

[0022] In In a preferred embodiment, the contact surfaces of the two conductors are aligned longitudinally. This results in a compact design. In the embodiment with angled conductor ends, specifically with the end sections oriented parallel to the surface of the support component, the contact surfaces, and thus the end sections of the two conductors, are angled in opposite directions and are preferably at the same level. This results in a very compact design overall, and the contact surfaces are virtually flush with the surface of the support component. In In one design variant, the end sections lie, for example, on the surface of the supporting component or are only slightly spaced from it, for example by a few millimeters up to, for example, 10-20 mm.

[0023] In a preferred embodiment, several pairs of conductors, and thus in particular several sandwich structures, are arranged side by side, i.e., in the transverse direction Q perpendicular to the longitudinal direction L. This arrangement creates multiple electrical conductor strands within the supporting component. Current can be distributed across these strands, thus minimizing the load on a single conductor strand. Each sandwich structure can therefore be smaller and designed for a lower current-carrying capacity. This facilitates integration into the supporting component, as the sandwich structure does not need to be as robust. By distributing the load across multiple sandwich structures, the integrity and thus the load-bearing capacity of the supporting component are only minimally affected.

[0024] The two conductors of the conductor pair preferably form a forward and a return conductor when installed. One conductor, when connected and installed in the vehicle, is connected to a supply voltage, and the other conductor is connected to ground potential. Specifically, the power cable is a direct current (DC) line between two electrical components.

[0025] According to the invention, the problem is further solved by a vehicle electrical system component comprising a chassis support component made of a fiber-reinforced composite material with at least two electrical conductors of a power train extending in a longitudinal direction and embedded in the support component, wherein the two conductors are electrically connected to each other. The two conductors form an electrically connected conductor group.

[0026] The electrical connection advantageously achieves a division of the entire power string into several sub-strings, so that the individual sub-strings and thus conductors can be less massive and thus impair the integrity of the supporting component less, as was previously done in connection with the sandwich structures arranged side by side.

[0027] This solution according to the invention with the electrically connected conductors is preferably combined with the sandwich structure described above, in which the elastomeric insulating layer is arranged between two conductors.

[0028] The two conductors of the conductor group are, for example, the two conductors of the sandwich structure, i.e., the conductors of the conductor pair are electrically connected to each other. In a preferred embodiment, however, at least two sandwich structures are provided, and the two conductors of the conductor group are each formed by one conductor of the respective sandwich structure.

[0029] The conductors of the conductor group are in particular flat conductors, especially solid flat conductors and especially busbars or conductor rails.

[0030] In a preferred embodiment, the two conductors of the conductor group are arranged side by side within the support component, i.e., they are arranged next to each other in a direction transverse to the longitudinal direction. Since the support components typically have a limited thickness, the distribution of the multiple conductors of the conductor group in the transverse direction (and thus perpendicular to the thickness direction) achieves good distribution within the fiber-reinforced composite material, and its integrity is only minimally affected.

[0031] In a preferred embodiment, the at least two conductors of the conductor group are electrically connected in parallel via the electrically conductive connection. This results in a distribution of the current load across the multiple conductors during operation, as previously described.

[0032] For this purpose, the at least two conductors of the conductor group are preferably electrically connected to each other at at least one of their conductor ends and in particular at both conductor ends.

[0033] Alternatively, it is also possible that the conductors are connected in series.

[0034] In a practical design, the conductors also have conductor ends on both sides that extend from the supporting component. The electrically conductive connection between the two conductors is preferably made directly at the supporting component and thus directly within the area of ​​the supporting component.

[0035] As previously described, the conductor ends preferably have angled contact surfaces that run parallel to the surface of the support component. For the specific design of these angled conductor ends, reference is made to the preceding description in connection with the sandwich structure. These contact surfaces protruding from the support component are electrically connected to each other via a conductor element. For this purpose, a flat conductor is provided in each case, specifically a conductor rail designed like a connecting plate.

[0036] Generally, the at least two conductors of the conductor group are electrically connected to each other via a conductor element. This conductor element preferably forms a common connection terminal for the conductor group. Specifically, in the embodiment where the conductor element connects the contact surfaces, a connection terminal is thus created directly on the top side of the support component, through which the supply line can be connected to the rest of the vehicle's electrical system. This is achieved, for example, by the connection terminal having a terminal bolt to which an electrical conductor can be connected via a suitable contact connector, such as a contact shoe.

[0037] According to a preferred embodiment, several pairs of conductors constructed in a sandwich design are arranged next to each other.

[0038] Each pair of conductors preferably defines a forward conductor and a return conductor when connected, specifically in a DC line. The forward conductor forms a supply line and is typically connected to a positive terminal, and the return conductor forms a ground conductor and is typically connected to ground potential.

[0039] The two conductors of the sandwich-constructed conductor pair are therefore not electrically connected to each other. At the same time, the conductors of each conductor pair are electrically connected to the conductors of the other conductor pair. The two outgoing conductors and the two return conductors of the two adjacent conductor pairs are therefore electrically connected to each other and each form a conductor group, as described previously.

[0040] According to a preferred embodiment, it is further provided that, in the connected state, the conductors are connected to different voltage sources with different voltage potentials. This provides multiple voltage levels and thus partial electrical systems. Therefore, several power lines are designed for different voltage levels. For at least one, and preferably for each, voltage level, at least two pairs of conductors are preferably designed in a sandwich construction, the conductors of which are electrically connected to each other to form the conductor groups.

[0041] In general, it is possible to use more than two conductors, for example three, four, or even more, in both conductor groups with electrically interconnected conductors and conductors stacked in a sandwich construction with an intervening elastomeric insulating layer. In the case of the sandwich construction, adjacent conductors (conductor pairs) are separated from each other by the elastomeric insulating layer, with the conductors in direct contact with the insulating layer. In the case of the conductor group, the multiple conductors are electrically interconnected and preferably arranged side by side in the transverse direction. Preferably, in all embodiments, only the fiber-reinforced composite material is used as insulating material between the conductors of the conductor group.

[0042] An embodiment of the invention is explained in more detail below with reference to the figures. These show simplified representations. FIG 1 a perspective partial view of a vehicle electrical system component, FIG 2 a longitudinal section through the vehicle electrical system component according to FIG 1 FIG 3 shows a partial representation of a sandwich structure of a conductor pair with an insulating layer arranged between them, and FIG 4 shows a partial and schematic representation of a motor vehicle.

[0043] In FIG 1 Figure 2 is a vehicle electrical system component, for example, a vehicle floor of a motor vehicle, shown in a partially and highly schematically represented manner. The vehicle electrical system component 2 has a support component 4 made of a fiber-reinforced composite material, for example, CFRP or GFRP. Several power lines 6 are integrated into this support component 4, which are part of a vehicle electrical system (not shown in detail here). The power lines 6 are embedded in the fiber-reinforced composite material. This means that they are completely surrounded by the material of the support component 4, except for their end sections.

[0044] In the present context, power train 6 refers to a conductor arrangement that connects two electrical components of the vehicle electrical system for power supply. In the embodiment according to the Figur 1 Several power strands 6 are formed, namely a total of three power strands 6.

[0045] Each power string 6 has at least one sandwich structure 8 with two conductors 10 designed in the manner of conductor rails, which are arranged one above the other with an insulating layer 12 in between. FIG 1 A total of four such sandwich structures 8 are shown. The two middle sandwich structures 8 are connected to each other via conductor elements 14 and thus form two partial strands of a common power strand 6.

[0046] The in FIG 1 The illustrated on-board network component 2 is used, for example, in an on-board network with multiple power sources and multiple voltage levels. For instance, the central power line 6, formed by the two interconnected sandwich structures 8, is connected to a first power source, for example, with a supply voltage of 12 V. The two outer sandwich structures 8 each form their own power line 6 and are connected, for example, to a second power source, for example, with a supply voltage of 48 V.

[0047] The insulating layer 12 - as especially made up of FIG 2 und FIG 3 As can be seen from the diagram, the insulating layer 12 is located directly adjacent to the two conductors 10. Otherwise, the conductors 10 are surrounded by the insulating material of the fiber composite. The conductors 10 are, in particular, bare conductor rails made of solid metal, specifically copper or aluminum. The insulating layer 12 is formed by a ribbon-shaped insulating strip, which preferably has the same width as the conductors 10, as shown in the diagram. FIG 3 proceeds. The insulating layer 12 consists of an elastomeric material, specifically rubber.

[0048] The insulating layer 12 serves, firstly, to electrically insulate the two conductors 10 from each other. Secondly, due to its elasticity, it serves as vibration protection and / or to compensate for thermally induced expansion of the conductors 10.

[0049] The respective sandwich structure 8 and thus also the ladder 10 extend in a longitudinal direction L. Perpendicular to this, the ladder 10 have a width in the transverse direction Q and the entire sandwich structure 8 has a height in a vertical direction V.

[0050] The individual sandwich structures 8 are each embedded in the supporting component 4 and are preferably arranged at the same height (viewed in the vertical direction V). The individual conductors 10, i.e., the upper conductors 10 and the lower conductors 10 of a respective sandwich structure 8, preferably lie within a common plane, which is spanned by the longitudinal direction L and the transverse direction Q.

[0051] Each conductor 10 has angled conductor ends 14 at both of its ends. As can be seen specifically from the FIG 2 As can be seen, the upper conductor 10 has U-shaped angled conductor ends 16 and the lower conductor 10 has approximately Z-shaped angled conductor ends 16.

[0052] The conductor ends 16 each have a section extending approximately in the vertical direction V, which leads out of the support component 4 and to which an end section is connected outside the support component 4, each of which forms a contact surface 18. The end sections, and thus the contact surfaces 18, preferably extend parallel to a surface of the support component 4. The end sections of the upper conductor are oriented towards each other, and the end sections of the lower conductor are oriented in opposite directions.

[0053] The conductors 10 are, with the exception of the end section – and optionally a portion of the section oriented in the vertical direction V – completely integrated into the support component 4. Preferably, the end section, which forms the contact surface 18, rests directly on the top surface of the support component 4, as shown by FIG 2 This can be seen from the contact surfaces 18. Each of these surfaces provides a contact point for further connection elements.

[0054] As can be seen specifically from the cross-sectional view of the FIG 2 As a result, the insulating layer 12 is also arranged in the vertically extending sections between the two conductors 10. This allows the insulating layer 16, due to its elasticity, to very effectively compensate for expansions of the conductors 10 in the longitudinal direction L.

[0055] The two conductors 10 of each sandwich structure 8 form a conductor pair A. In the exemplary embodiment, one conductor 10 of the conductor pair A is connected to a supply voltage and the other conductor 10 to a ground potential. The two conductors 10 of the conductor pair A thus form the forward and return conductors of a DC power supply line.

[0056] The previously mentioned conductor elements 14, which are specially designed like connecting plates, connect the contact surfaces 18 of the conductors 10 of adjacent sandwich structures 8. Specifically, the conductors 10 at the same voltage potential are connected to each other. Each pair of connected conductors 10 from adjacent sandwich structures 8 forms a conductor group B. The conductors 10 of each conductor group B are therefore connected in parallel, so that the entire power string 6 is divided into two sub-strings. The conductor elements 14 are attached to the contact surfaces 18, in particular by a material bond, for example, by welding. Alternatively, they are connected via screw connections.

[0057] In principle, it is possible that special contact connections, such as connecting bolts, are formed on the end sections / contact surfaces 18 or on the conductor elements 14, so that the end sections or the conductor elements 14 each form connection terminals to which outgoing conductor arrangements, such as conventional sheathed cables or other busbars, can be connected.

[0058] In FIG 4 The positioning of the vehicle electrical system component 2 within a motor vehicle 22, specifically a fully electric motor vehicle 22, is shown as an example. FIG 4 Only one power train 6 is shown as an example, which is formed from two sub-trains, each with a sandwich structure 8. The two sandwich structures 8 are connected to each other on both sides via two conductor elements 14. In the exemplary embodiment, the vehicle electrical system component 2 is formed in particular by a floor 20 of a passenger compartment. Below this floor 20 is a FIG 4 The traction battery 24, shown in dashed lines, is arranged and serves as a DC power source and to supply an electric drive motor 26. The power train 6 connects the traction battery 24 to an inverter 28 assigned to the drive motor 26. It connects one positive and one negative terminal of the battery 24 to corresponding terminals on the inverter 28.

[0059] Alternatively, the power train 6 connects the battery 24 to, for example, a power distributor to which several electrical consumers are connected.

[0060] As from Fig 4As can be seen, connecting cables 30 are attached to the ends of the power train 6, for example, in the form of conventional sheathed cables. A respective ground conductor or supply conductor of the power train 6 is connected via the connecting cables 30 to the positive terminal or negative terminal of the respective electrical component 24, 28. The connecting cable 30 is typically a two-core cable. Each core is connected to one of the two conductor elements 14 of the power train 6. The traction motor 26 and the inverter 28 are arranged in a motor compartment 32, and in the exemplary embodiment, the connecting cable 30 is routed through an end wall 34 into the motor compartment 32.

[0061] The invention is not limited to the embodiment described above. Rather, other variants of the invention can also be derived by a person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the embodiment can also be combined with one another in other ways without departing from the subject matter of the invention. Reference symbol list

[0062] 2 On-board electrical system component 4 Support component 6 Power train 8 Sandwich structure 10 Conductor 12 Insulation layer 14 Conductor element 16 Conductor end 18 Contact surface 20 Ground 22 Vehicle 24 Battery 26 Traction motor 28 Inverter 30 Connecting cable 32 Engine compartment 34 Front wall Longitudinal direction, Transverse direction, Vertical direction

Claims

1. An on-board network component (2) for a motor vehicle, with a chassis support component (4) of a fibre-reinforced composite material, with at least two electrical conductors (10) of an electrical power cable (6), extending in a longitudinal direction (L), which form a pair of conductors (A) and which are flat conductors, wherein the pair of conductors (A) is embedded into the support component (4), such that the pair of conductors (A), viewed in cross-section, is directly and on its entire periphery surrounded by the material of the fibre-reinforced composite material, characterized in that the conductors (10) are separated by an insulating layer (12) of an elastomeric material, wherein the insulating layer (12) is placed between both electrical conductors (10) in the manner of an insulating strip, such that a stacked sandwich structure (8) is formed from the conductors (10) and the insulating layer (12), which is inserted as an insert element into the component (2).

2. The on-board network component (2) according to the preceding claim, characterized in that the insulating layer (12) consists of a rubber or a thermoplastic elastomer.

3. The on-board network component (2) according to any one of the preceding claims, characterized in that the insulating strip has the same width as the flat conductors.

4. The on-board network component (2) according to any one of the preceding claims, characterized in that the conductors (10) have conductor ends (16) that protrude from the support component (4) and form a contact surface (18) outside the support component.

5. The on-board network component (2) according to the preceding claim, characterized in that the conductors (10) are configured as a U or Z shape at the ends (16) of the conductors.

6. The on-board network component (2) according to any one of the two preceding claims, characterized in that the contact surfaces (18) of both conductors (10) connect to each other in the longitudinal direction (L).

7. The on-board network component (2) according to any one of the preceding claims, characterized in that several pairs of conductors (A) are arranged side by side.

8. The on-board network component (2) according to any one of the preceding claims, characterized in that, in the mounted state, one of the conductors (10) of the pair of conductors is connected to ground potential and the other conductor (10) is connected to a supply voltage.

9. The on-board network component (2) according to any one of the preceding claims, characterized in that the at least two conductors (10) are electrically connected to each other and form a conductor group (B).

10. The on-board network component (2) according to the preceding claim, characterized in that two sandwich structures (8) are arranged side by side in the transverse direction (Q), wherein both conductors (10) of the conductor group (B) each are formed by a conductor (10) of the respective sandwich structure (8), such that the at least two conductors (10) of the conductor group (B) are arranged side by side in the transverse direction (Q).

11. The on-board network component (2) according to any one of both preceding claims, characterized in that the at least two conductors (10) of the conductor group (B) are electrically connected in parallel.

12. The on-board network component (2) according to any one of claims 9 to 11, characterized in that the at least two conductors (10) of the conductor group (B) have conductor ends (16) which protrude from the support component (4) and are electrically connected to each other directly on the support component (4).

13. The on-board network component (2) according to any one of claims 9 to 12, characterized in that the conductor ends (16) have angled contact surfaces (18), which are electrically conductively connected by a conductive element (14).

14. The on-board network component (2) according to the preceding claim, characterized in that the conductive element (14) forms a common connection terminal for the conductor group (B).

15. The on-board network component (2) according to any one of the preceding claims, characterized in that, in the mounted state, the conductors (10) are connected to different voltage sources at different voltage potentials.