Structural element for a motor vehicle and method of manufacturing a structural element

Abstract

Structural element for a motor vehicle, in particular a frame part for a chassis or a passenger compartment of the motor vehicle, having at least a first and a second fiber layer forming a rigid fiber composite, the fiber layers being laminated to one another at least in sections, and at least one electrical flat conductor arranged between the fiber layers and laminated to the fiber layers. The flat conductor has a relief structure on at least one surface facing at least one fiber layer.

Claims

1. Motor vehicle structural element comprising: at least a first and a second fiber layer forming a rigid fiber composite, wherein the fiber layers are laminated to one another at least in sections, wherein the fiber composite is formed from fiber layers and a matrix of a composite material; and at least one electrical flat conductor arranged between the fiber layers and laminated with the fiber layers, wherein the flat conductor has a relief structure on at least one surface facing at least one fiber layer and the flat conductor is connected to the composite material via the relief structure in a form-fit, wherein the flat conductor and a second flat conductor overlap one another in sections and are electrically connected to one another in the area of the overlap.

2. Motor vehicle structural element according to claim 1, wherein the relief structure forms undercuts in the surface facing the fiber layer.

3. Motor vehicle structural element according to claim 1, wherein the relief structure is formed from protrusions and/or recesses, or wherein the relief structure is formed from recesses which penetrate through the flat conductor.

4. Motor vehicle structural element according to claim 1, wherein the flat conductor is formed as a grid.

5. Motor vehicle structural element according to claim 1, wherein the flat conductor is formed from aluminium material.

6. Motor vehicle structural element according to claim 1, wherein the fiber layers are formed from glass fibers, carbon fibers, ceramic fibers, aramid fibers, boron fibers, basalt fibers, natural fibers, nylon fibers, and/or wherein the composite material is formed from a polymer, a duroplast, synthetic resin, elastomer, and/or thermoplastic.

7. Motor vehicle structural element according to claim 1, wherein the flat conductor is deep-drawn together with the fiber layers.

8. Motor vehicle structural element according to claim 1, wherein the flat conductor is formed as at least one electrically closed conductor loop in the structural element.

9. Motor vehicle structural element according to claim 1, wherein the flat conductor extends along an entire length of the structural element.

10. Motor vehicle structural element according to claim 1, wherein at least one connection console is formed on the flat conductor, and wherein the connection console is routed out of the fiber composite.

11. Motor vehicle structural element according to claim 1, wherein a number of connection consoles are arranged on the flat conductor which exceeds the number of actual electrical connections on the flat conductor, so wherein the assembled state at least one connection console is free of an electrical connection.

12. Motor vehicle structural element according to claim 1, wherein at least two mutually insulated flat conductors are routed in the fiber composite.

13. Motor vehicle structural element according to claim 1, wherein the flat conductor is electrically connected to a first flexible cable via a connection console, and wherein the second flat conductor is electrically connected to a second flexible cable via a connection console.

14. Motor vehicle structural element according to claim 1, wherein at least one flexible cable is connected to a pole of a battery via a battery pole clamp.

15. Motor vehicle structural element according to claim 1, wherein the flat conductor and the second flat conductor are electrically connected to one another in the area of the overlap in a form-fit.

16. Motor vehicle structural element according to claim 1, wherein the structural element is at least part of a front axle module and/or of a passenger compartment.

17. Motor vehicle structural element according to claim 1, wherein at least one flat conductor is routed out of the structural element and projects into a rear vehicle area.

18. Method of manufacturing a structural element, according to claim 1, with the steps of providing a first fiber layer, placing a flat conductor with a surface with a relief structure onto the first fiber layer, providing a second fiber layer, laminating the first fiber layer, the second fiber layer, and the flat conductor with a matrix of a composite material in such a way that the flat conductor is connected to the composite material via the relief structure in a form-fit.

19. Method according to claim 18, wherein the first fiber layer, the flat conductor and the second fiber layer are deep-drawn, and subsequently the formed layers are laminated with the composite material so that the layers form a laminate.

20. Motor vehicle structural element according to claim 1, wherein the flat conductor and the second flat conductor are electrically connected to one another in the area of the overlap in a material-bond.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the subject matter is explained in more detail with reference to a drawing showing embodiments. In the drawing show:

(2) FIG. 1a-d different surface structures of flat conductors according to embodiments;

(3) FIG. 2a a cross-section through a structural element with a fiber composite and a flat conductor with a second relief structure;

(4) FIG. 2b a cross-section through a structural element with a fiber composite and a flat conductor with a third relief structure;

(5) FIG. 2c a cross-section through a structural element with a fiber composite and a flat conductor with a first relief structure;

(6) FIG. 3a-b a flat conductor with a lattice-like surface structure;

(7) FIG. 4a-d a flat conductor with different lattice-like structures;

(8) FIG. 5 structural elements with flat conductors and fiber composites;

(9) FIG. 6a-b a structural element with a fiber composite and flat conductors;

(10) FIG. 7 various connection consoles on flat conductors.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

(11) FIG. 1a shows a flat conductor 2, which may be formed from one of the abovementioned materials. The flat conductor 2 has a rectangular cross-section and two wide surfaces 2a and two narrow surfaces 2b as well as two end faces 2c.

(12) On at least one of the surfaces 2a, b, a relief structure 4 such as is on the surface 2a in FIG. 1a can be embossed. The surface structure provided in FIG. 1a is a grid structure and regular.

(13) FIG. 1b shows another example embodiment in which the surface structure 4 on the surface 2a is irregular, for example by introducing an increased roughness.

(14) FIG. 1c shows another example of a flat conductor 2 in which an undulating, regular relief structure is applied to the surface 4 on each of the surfaces 2a and 2b.

(15) FIG. 1d shows a further example of an embodiment of a flat conductor 2 in which a strip-shaped relief structure 4 is applied.

(16) The relief structure 4 can either be applied uninterruptedly along a longitudinal axis on one, two, three or four surfaces 2a, 2b, or areas with a relief structure can be spaced apart by areas without a relief structure.

(17) FIG. 2a shows a cross-section (strongly simplified) through a flat conductor 2 according to FIG. 1d in a fiber composite. The flat conductor 2 is incorporated in a fiber composite 6. The fiber composite 6 is formed of fiber layers 6a-d, which are stacked on top of each other. Between two fiber layers 6b, c, the flat conductor is included in the composite structure. A matrix of a composite material 8 is introduced between the fiber layers 6a-d of the composite structure 6. It can be seen that the composite material 8 is not only introduced between the fiber layers 6a-d, but penetrates into the relief structure of the surface of the flat conductor 2. After curing of the composite material 8, the laminate of the fiber layers 6a-d and the flat conductor 2 is bonded by the composite material 8. The protrusions and recesses in the surface of the relief structure 4 result in a considerably improved form fit between the fiber composite 6 and the flat conductor 2, so that delamination is counteracted.

(18) FIG. 2b shows a flat conductor 2 with a relief structure that has undercuts. It can be seen that the undercuts undercut the surface of the flat conductor that is adjacent to the fiber composite 6. The composite material can, as long as it is liquid, penetrate into these undercuts. When the composite material 8 has cured, it is interlocked with the undercuts so that the fiber composite 6 is held positively against the flat conductor 2.

(19) FIG. 2c shows another possible relief structure. Here, the surface of the flat conductor is porous with a penetration depth of up to, for example, 10 mm, preferably also 20 mm, in particular less than 20% of the total thickness of the flat conductor 2. The porosity is an open porosity with a pore size of more than 50 nm. The porosity is between 10% and 40%, preferably less than 50%, in particular less than 40% or less than 30%. Preferably, the porosity is more than 5% or 10%. The pores form the undercuts of the relief structure into which the composite material 8 can penetrate.

(20) FIG. 3a shows another flat conductor 2 which is lattice-shaped and has openings. Along section IIIb, which is shown in 3b, it can be seen that the composite material 8 penetrates into the lattice structure and is arranged between the webs of the flat conductor 2. After curing of the composite material 8, there is also a very good connection by form fit between the fiber layers 6a-d and the flat conductor 2.

(21) FIGS. 4a-d show various types of lattice structures, FIG. 4a showing a hexagonal lattice structure, FIG. 4b showing a first diamond-shaped lattice structure, FIG. 4c showing a coarse diamond-shaped lattice structure and FIG. 4d showing a square lattice structure, each with openings and webs of the flat conductor 2. These and other lattice structures are suitable for forming the structural element according to the subject matter. The lattice structures can be formed from expanded metal or wires.

(22) FIG. 5 schematically shows the structure of a motor vehicle with different structural elements. The motor vehicle has a crash structure 10, a front axle module 12, a passenger compartment 14 and a rear body 16. In particular, the structural elements in the areas 12, 14, 16 may be formed of a fiber composite material. In one or more structural elements in the areas 12-16, a flat conductor 2 may be introduced either as a single layer or in multiple layers with two flat conductor layers 2′, 2″. The two flat conductor layers 2′, 2″ can be electrically insulated from one another by at least the composite material, but in particular also by at least one fiber layer. Electrical connections 18a, 18b can be provided on the flat conductor layers 2′, 2″, for example in the region of the rear body 16. These electrical connections may be formed by flexible leads connected to a motor vehicle battery 20, for example, each with one pole of each of the batteries 20.

(23) In each of the areas 12, 14, a structural element with a flat conductor 2 in it may be hermetic, and at the transitions between the areas 12-16, the respective flat conductors 2 may be led out of the composite material and short-circuited to each other.

(24) Connection consoles 22 may be provided at one or more of the flat conductor layers 2′, 2″. The connection consoles 22 can be equipped with electrical conductors 24 as required, in accordance with the respective requirement of an equipment variant. The number of connection consoles 22 can be greater than the actual number of connected electrical conductors 24 to accommodate different requirement variants.

(25) FIG. 6a shows a structural element, for example a frame 26 with 5 layers, wherein two flat conductor layers 2′, 2″ are arranged between respective fiber layers 6a-d. Each of the flat conductor layers 2′, 2″ may have at least one connection console 22.

(26) The arrangement of the flat conductor or the flat conductor layers 2′, 2″ in the fiber composite is shown again in FIG. 6b. The flat conductor layers 2′, 2″ can be integrated between the fiber layers 6a-d and a composite material 8.

(27) FIG. 7 shows a flat conductor 2 in a composite layer 6 with two connection consoles 22, which branch off from the flat conductor 2 transversely to the longitudinal axis of the flat conductor 2. A connection console 22 may be formed bimetallically as a first material 22a and a second material 22b. In this context, for example, the material 22b, which is connected to the flat conductor 2 in a material bond, for example, may be formed from the same material as the flat conductor 2, and the area 22a may be formed from a metal material that is different therefrom. For example, the metal material of the area 22b can be an aluminium material and the area of the material 22a can be a copper material. Thus, an electrical cable 24 made of aluminium, for example, can be very easily connected to the copper material in the region 22a by means of soldering, crimping or the like.

LIST OF REFERENCE SIGNS

(28) 2 flat conductor 2′, 2″ layers 2a-c surfaces 4 relief structure 6 fiber composite 6a-d fiber layers 8 composite material 10 crash structure 12 front axle module 14 passenger compartment 16 rear body 18a, b battery cables 20 automotive battery 22 connection console 24 flexible cable 26 frame structure