WO2019105760A1

WO2019105760A1 - Hybrid underbody protection device for a battery housing

Info

Publication number: WO2019105760A1
Application number: PCT/EP2018/081492
Authority: WO
Inventors: Dieter Kalemba; Fabian Schongen; Vanessa Wieschalla; Lothar Patberg; Daniel Nierhoff
Original assignee: Thyssenkrupp Steel Europe Ag; Thyssenkrupp Ag
Priority date: 2017-11-28
Filing date: 2018-11-16
Publication date: 2019-06-06
Also published as: DE102017221345A1

Abstract

The present invention relates to an underbody protection device for a motor vehicle, in particular for protecting a drive battery, wherein the underbody protection device comprises a base plate and an underride guard, the base plate and the underride guard being arranged in such a way that they at least partially enclose an intermediate space, wherein the base plate and/or the underride guard has a plastic layer. The present invention further relates to a method for producing such an underbody protection device.

Description

DESCRIPTION

title

Hybrid underbody protection device for battery case

State of the art

The present invention relates to an underbody protection device for a motor vehicle, in particular for the protection of a drive battery, wherein the underbody protection device comprises a bottom plate and an underrun protection, wherein the bottom plate and the underrun protection are arranged so that they at least partially enclose a gap. The invention further relates to a method for producing such a underbody protection device.

The drive battery of an electric vehicle is often mounted in the vehicle floor, resulting in the technical problem of storing the battery so that it is sufficiently protected against the penetration of foreign bodies from the outside space under the vehicle, or a strong deformation of the vehicle floor.

For storage of energy storage cells, a module is known for example from DE 10 2011 076 575 A1, in which the cells are arranged between two end plates and are braced by at least one tension element. The end plates in this case have a layer structure in which at least one wave-like shaped inner layer is surrounded by two outer layers. This design allows cells to be stably and low-weight combined in one module and to compensate, to some extent, for the deformations that occur due to pressure changes during operation of the storage cells. In contrast, to counteract deformations that occur due to strong external influences, such as the abrupt deformation of the vehicle, the layer structure is not sufficient because it distributes only the mechanical stress by relatively rigid elements on the entire surface of the end plates.

Disclosure of the invention

Against this background, it is an object of the present invention to provide a protective device that provides the drive battery against an unduly high load protects, which can be caused by a deformation or a failure of the vehicle floor due to the impact of a foreign body.

To achieve the object, an underbody protection device for a motor vehicle is proposed, in particular for the protection of a drive battery, wherein the underbody protection device has a base plate and an underrun protection, wherein the base plate and the underride protection are arranged such that they at least partially enclose a gap, wherein the bottom plate and / or the underrun protection has a plastic layer.

In the case of the underbody protection device according to the invention, the vehicle floor is protected by the double structure consisting of base plate and underrun protection against the exterior of the vehicle. For spatial description, the vertical to the direction of travel vertical is used, with respect to which the various elements can be arranged below or above each other. In the plane perpendicular to the vertical, the direction of travel is referred to as the longitudinal direction and the direction perpendicular to the vertical and to the longitudinal direction is referred to as the transverse direction. The bottom plate forms a partition of the substantially sealed inside of the battery case, in which various electronic assemblies and in particular the drive battery are mounted. The battery case can be an independent, detachable assembly or insoluble part structure of the vehicle body. The underride guard is disposed below the bottom plate and spaced from the bottom plate so that a gap is formed between the two. Both the bottom plate and the underrun protection are made of metal, preferably made of steel. In the space between the bottom plate and the underrun protection a plastic layer is arranged. Preferably, the plastic layer is made of a thermoplastic material and the bottom plate and / or the underrun protection provided with an optimized surface or a plastic coupling layer over which a material and / or positive connection with the plastic layer is made possible. The hybrid structure of base plate, plastic layer and underrun protection on the one hand forms an additional protective barrier between the outer space and the interior of the battery housing and on the other hand can preferably assume additional functions according to the invention, such as thermal insulation between the cooling of the drive battery and the vehicle floor or the Street. Further possible functions are described in the following preferred embodiments of the invention. Due to the intermediate space and the plastic layer, with this hybrid structure it is advantageous to have one, compared to a monolithic one. A particularly light design or a deformation space for targeted energy dissipation when a foreign body impact from below is realized.

If, for example, the underrun protection is so severely deformed by an accident that contact between the floor slab and underride protection would occur, the plastic layer can preferably be used to dampen the movement of the underrun protection to the extent that a mechanical contact between the floor slab and underrun protection is avoided. Such damping is already achieved by a simple plastic layer, which absorbs the impact energy by deforming itself elastically or plastically. An improved energy absorption compared with this simple embodiment can be achieved by means of a number of special designs of the plastic layer.

According to a preferred embodiment of the invention, the plastic layer consists of a fiber-reinforced plastic. As a result, the material properties of the plastic matrix can advantageously be combined with those of the fiber material, which in particular results in lower weight and higher strength or rigidity.

According to a preferred embodiment of the invention, a side of the plastic layer facing the intermediate space has a modulated contour. In this case, the contour can be, for example, wave-shaped or zigzag-shaped, with the waves or prongs being oriented in the longitudinal direction or transverse direction. Alternatively, grooves, bumps or nubs are conceivable. By means of such a modulation, the energy absorption can be advantageously improved if the underrun protection is so strongly deformed that it presses the plastic layer against the bottom plate.

According to a preferred embodiment of the invention, the plastic layer is connected to the bottom plate and / or the underrun protection via shock absorbing elements. Such shock absorbing elements can be formed by parts of a viscoelastic plastic, a porous foam, a nonwoven fabric or gel pads which have a strong damping effect against abrupt loads, shock waves or vibrations. As a result, it is advantageously possible to intercept strong and sudden contractions of the gap between the base plate and underrun protection and to prevent a critical transfer of energy to the overlying structure and thus the deformation of the base plate. According to a preferred embodiment of the invention, the plastic layer has at least one macroscopic cavity. The term "macroscopic" is used herein to distinguish the preferred cavities according to the invention from, for example, the smaller cavities of a porous structure. According to the invention, these are preferably chambers or channels in the size range of a few millimeters to one meter, which are formed in the plastic. With such macroscopic cavities, the energy absorption is increased, which intercepts the impact effect in the event of a rapid contraction of the space between the base plate and underbody protection. Furthermore, vibration damping or thermal insulation can advantageously be realized via such macroscopic cavities. According to the invention, the plastic layer preferably has a plurality of such macroscopic cavities.

According to a preferred embodiment of the invention, the plastic layer has at least one macroscopic cavity which is filled with a solid or liquid or gaseous medium. Preferably, the medium is a viscoelastic plastic or gel. As a result, it is advantageously possible to increase the absorption capacity of the plastic layer in relation to impact-like stresses. Furthermore, either an increased thermal insulation can be achieved via a suitably selected medium or an improved temperature compensation can be achieved by a medium having a correspondingly high thermal conductivity.

According to a preferred embodiment of the invention, the plastic layer is arranged on the underbody protection. This has the advantage, for example, that the joining of the plastic layer and underrun protection can be carried out in a first production step and the underrun protection provided with the plastic layer can then be attached as a whole to the bottom of the vehicle, in particular detachably below the bottom plate. The assembly can then be easily replaced as a sacrificial part in case of uncritical damage. According to a particularly preferred embodiment of the invention, the underride protection together with the plastic layer forms a metal-plastic-metal sandwich structure. The plastic layer is surrounded by two metallic layers, for example in the form of steel sheets. The composite structure thus formed combines the strength of the metal layers with the advantageous properties of the plastic, such as the ability to absorb shocks and vibrations. According to a particularly preferred alternative embodiment, the underrun protection forms a metal-plastic two-layer structure together with the plastic layer. The plastic layer is, for example, by gluing, injection molding, extrusion, thermal pressing, calendering or laminating on the, applied to the gap between the bottom plate and underride guard side of the lower plate.

According to a preferred embodiment of the invention, the plastic layer is arranged on the bottom plate. According to a particularly preferred embodiment, the plastic layer has one or a plurality of fastening domes. The attachment domes are formed by protruding parts of the plastic layer and serve to secure the bottom plate. The underride guard can be connected to the bottom plate by means of fasteners, such as screws, by countersunk the fastener into the mounting dome. As a result, a bore in the bottom plate can advantageously be dispensed with.

Another object of the invention is a method for producing a subfloor structure described above. According to a preferred embodiment of the invention, the bottom plate and / or the underrun protection is formed in a first process step of a metal sheet and applied the plastic layer by gluing, injection molding, thermal pressing, extrusion, lamination or calendering on the bottom plate or underrun protection. One of the forming methods for metal sheets familiar to the person skilled in the art can be used for the shaping of the base plate or underbody protection. The metal sheet itself is preferably made of steel, although other metals are conceivable. Preferably, it is a high-strength material with which sufficient strength or rigidity can be achieved with a small thickness. The metal sheet is particularly preferably a corrosion-resistant, coated steel sheet in order to achieve high media resistance. For example, the steel sheet can be galvanized or provided with a zinc-magnesium coating. The plastic is preferably a thermoplastic such as, for example, acrylonitrile-butadiene-styrene (ABS), polyamides (PA), polyactate (PLA), polymethylmethacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET) , Polyurethane (PU), Polyphenylsulfide (PPS), Polysulfone (PSU), Polyethylene (PE), Polypropylene (PP), Polystyrene (PS), Polyetheretherketone (PEEK), Polyvinylchloride (PVC), and other or mixtures and compounds of these plastics. Also possible are duroplastic plastics, elastomers and thermoplastic elastomers. Further possible materials are high-performance plastics for applications at higher temperatures, such as polyaryls, aromatic polyesters (polyarylates) and polyamides (polyaramides), such as polyphenylene isophthalamide (PMI), heterocyclic polymers, such as polyimides, polybenzimidazoles and polyetherimide, polyetherimides, polybenzimidazoles ( PBI), aromatic polyamides Based on poly-m-phenylene isophthalamide (PMI), polyaramide fibers, liquid crystal polymers (LCP Liquid Crystalline Polymers), fluoropolymers, perfluoroalkoxylalkane (PFA), polyphenylene etc. Denkar are also compounds in which base polymers are heat-activated by additives. and / or made electrically conductive

According to a preferred embodiment of the invention, the plastic layer by laminating, injection molding, extrusion, thermal pressing, calendering or gluing is applied to the bottom plate and / or underrun protection.

Further details, features and advantages of the invention will become apparent from the drawings, as well as from the following description of preferred embodiments with reference to the drawings. The drawings illustrate only exemplary embodiments of the invention, which do not limit the inventive concept.

Brief description of the figures

FIG. 1 shows a first exemplary embodiment of a underbody protection device according to the invention.

FIG. 2 shows a second embodiment of an underbody protection device according to the invention.

FIG. 3 shows a third embodiment of an underbody protection device according to the invention.

FIG. 4 shows a fourth exemplary embodiment of an underbody protection device according to the invention.

FIG. 5 shows a fifth exemplary embodiment of an underbody protection device according to the invention.

FIG. 6 shows a sixth exemplary embodiment of an underbody protection device according to the invention.

FIG. 7 shows a seventh embodiment of an underbody protection device according to the invention. Embodiments of the invention

In the various figures, identical parts are always provided with the same reference numerals and are therefore generally named or mentioned only once in each case.

FIG. 1 shows a first exemplary embodiment of a underbody protection device 1 according to the invention. Here and in the other figures, the vertical direction in the drawing plane corresponds to the vertical direction of the vehicle in normal position. That is, the illustrated underbody protection apparatus 1 is mounted on the underside of the vehicle, the floor panel 3 delimiting the interior of the vehicle at the bottom. Inside the vehicle, in particular the drive battery 2 is arranged together with the various electronic assemblies, which is protected by the underbody protection device 1 against the ingress of foreign bodies. Below the bottom plate 3, an underride guard 4 is arranged, so that the bottom plate 3 and the underride guard 4 include a gap 5, which acts as an additional protection zone in case of deformation of the underrun protection 4, so that the deformed underride guard 4 not in the bottom plate 3rd penetrates. In this embodiment, the underrun protection 4 consists of a composite structure of two metal layers which surround a plastic layer 6 and are connected to it in a positive and / or cohesive manner. The plastic layer 6 complements the strength and resilience of the two metal layers by the ability to dampen shocks or vibrations and to absorb the energy associated therewith by deformation work in a strong shock-like load.

FIG. 2 shows a second embodiment of an underbody protection device 1 according to the invention. In this embodiment, the underrun protection 4 consists of a two-layer structure, which is formed by a metal layer and a plastic layer 6. The metal layer and the plastic layer 6 are positively and / or materially connected to one another, so that the underrun protection 4, similar to the embodiment in FIG. 1, combines the advantages of the metal layer and the plastic layer 6 in it. The plastic layer 6 is arranged above the metal layer, so that the metal surface, which is harder than the plastic layer 6, forms a resistant outer surface of the underbody protection device 1. FIG. 3 shows a third embodiment of an underbody protection device 1 according to the invention. The bottom plate 3 and the underride guard 4 close the gap 5, in which the plastic layer 6 is arranged at the top of the underrun protection 4. The plastic layer 6 has on its upper side a modulated contour with a wave shape. If the underride guard 4 experiences a heavy load, deforms itself by the load and the gap 5 subsequently brews completely at least at one point, the wavy contour of the plastic ply 6 is pressed against the bottom plate 3, so that the movement of the underride guard 4 is damped is and deformation of the bottom plate 3 is prevented or at least mitigated.

FIG. 4 illustrates a fourth exemplary embodiment of an underbody protection device 1 according to the invention. The plastic layer 6 arranged on the upper side of the underrun protection 4 contains a plurality of macroscopic cavities 7 in the form of chambers 7, which are formed in the plastic. The chambers 7 are filled with a medium which can fulfill several functions. In the case in which the underrun protection 4 experiences a shock-like, heavy load and the gap 5 between the bottom plate 3 and underride guard 4 is at least partially pressed together, the medium can provide additional damping, which intercepts the movement of the underride guard 4 and so on large force effect on the bottom plate 3 prevented. For this purpose, the chamber 7 may be filled with a viscous or viscoelastic medium, for example a gel. A porous structure is also possible by which the kinetic energy is converted into deformation work and absorbed in this way. Other functions of the filled chambers may be to provide thermal insulation through reduced heat transfer. Conversely, a medium with high thermal conductivity can provide efficient temperature compensation. Other possible functions include sound or vibration damping. The chamber 7 may also simply contain a gaseous medium such as air, by which the impact of the underrun protection 4 is damped on the bottom plate 3.

FIG. 5 shows a fifth embodiment of an underbody protection device 1 according to the invention. The plastic layer 6 is attached in this embodiment to the underside of the bottom plate 3 and has a plurality of macroscopic cavities 7, which extend in the form of channels 7 perpendicular to the plane of the drawing. In the case in which the gap 5 is jerkily compressed, the plastic layer 6 with the channels 7 can at least partially absorb the impact energy and thus prevent penetration of the underrun protection 4 into the base plate 3. Furthermore, the channels 7 a Provide damping against shock or vibration and be filled for this purpose with a suitable medium. In a situation in which the temperature control of the intermediate space 5 is desirable, an improvement in the thermal insulation or an improvement in the temperature compensation can also be achieved via a medium with low or high thermal conductivity. It is also conceivable that the medium is introduced into the channels 7 via supply lines and so a regular or even continuous exchange of the medium is possible.

FIG. 6 shows a sixth embodiment of an underbody protection device 1 according to the invention. In this embodiment, the underride guard 4 is arranged with a fastening means 9 on the bottom plate 3. On the underside of the bottom plate 3, a plastic layer 6 is arranged, which in addition to a plurality of cavities 7 has one or more attachment domes 8. The fastening means 9 is sunk into the illustrated fastening dome 8, so that the connection between the base plate 3 and the underrun protection 4 takes place indirectly via the plastic layer 6. In this way, movements and vibrations of the underride guard 4 are damped by the plastic layer 6 and a transfer to the bottom plate 3 is reduced. In addition, additional openings or bores on the base plate for receiving the fastening means can advantageously be dispensed with in this way.

FIG. 7 shows a seventh exemplary embodiment of an underbody protection device 1 according to the invention. In this embodiment, the plastic layer 6 is attached to the top of the underride guard 4 and connected via shock absorbing elements 10 to the bottom plate 3. The shock-absorbing elements 10 are shown in the drawing by a general coupling 10, which is symbolically characterized by a parallel arrangement of a spring and a damping element. The coupling 10 transmits movements and in particular vibrations of the underrun protection 4 in an elastic, damped manner, in particular abrupt, rapid movements during the transmission suffer a high energy loss and the shock-like energy is thereby effectively absorbed. Such shock-absorbing elements 10 can be realized, for example, by viscoelastic polymer materials. LIST OF REFERENCE NUMBERS

1 underbody protection device

2 drive battery

3 base plate

4 underrun protection

5 gap

6 plastic layer

7 macroscopic cavity

8 fortification dome

9 fasteners

10 shock absorbing element

Claims

1. Underbody protection device 1 for a motor vehicle, in particular for the protection of a drive battery 2, wherein the underbody protection device 1 has a bottom plate 3 and an underrun protection 4, wherein the bottom plate 3 and the underrun protection 4 are arranged so that they at least partially enclose a gap 5, characterized characterized in that the bottom plate 3 and / or the underrun protection 4 has a plastic layer 6.

2. Underbody protection device 1 according to claim 1, wherein the plastic layer 6 consists of a fiber-reinforced plastic.

3. underbody protection device 1 according to claim 1 or 2, wherein a the intermediate space facing side of the plastic layer 6 has a modulated contour.

4. Underbody protection device 1 according to any one of the preceding claims, wherein the plastic layer 6 is connected to the bottom plate 3 and / or the underrun protection 4 via shock absorbing elements 10

5. Underbody protection device 1 according to any one of the preceding claims, wherein the plastic layer 6 has at least one macroscopic cavity 7.

6. Underbody protection device 1 according to claim 5, wherein the at least one macroscopic cavity 7 is filled with a solid or liquid or gaseous medium.

7. Underbody protection device 1 according to one of the preceding claims, wherein the plastic layer 6 is arranged on the underrun protection 4.

8. Underbody protection device 1 according to claim 6, wherein the underrun protection 4 together with the plastic layer 6 a metal-plastic-metal sandwich structure bil det.

9. Underbody protection device 1 according to claim 6, wherein the underrun protection 4 together with the plastic layer 6 forms a metal-plastic two-layer structure.

10. Underbody structure 1 according to any one of claims 1 to 6, wherein the plastic layer 6 is arranged on the bottom plate 3.

1 1. Underbody structure 1 according to claim 10, wherein the plastic layer 6 has one or a plurality of Befestigungsdomen 8.

12. A method for producing an underbody structure 1 according to one of claims 1 to 11, wherein the bottom plate 3 and / or the underrun protection 4 is formed in a first process step from a metal sheet and the plastic layer 6 by gluing, injection molding, thermal pressing , Extrusion, laminating or calendering

13. The method according to claim 12, wherein the plastic layer 6 is applied to the bottom plate 3 and / or the underrun protection 4 by lamination, injection molding, extrusion, thermal pressing, calendering or gluing.