Motor vehicle with underride protection

Abstract

A motor vehicle (100) having an underride guard (1) is proposed, wherein the underride guard (1) has an EMC shield (2).

Description

[0001] The present invention relates to a motor vehicle with an underrun protection.

[0002] Modern motor vehicles feature a multitude of electrical and electronic components. Particularly in vehicles with electric drive systems, such as hybrid vehicles or electric vehicles, powerful electric motors, highly resilient power electronics, and high-voltage batteries are required.

[0003] Electrical and electronic components emit electrical or electromagnetic fields by design. To ensure that these emitted electrical or electromagnetic fields do not interfere with other components, or to ensure that the electrical or electronic component itself is not disturbed by fields from other components, measures are prescribed that lead to what is known as electromagnetic compatibility of the components. Electromagnetic compatibility, or EMC for short, is defined in the European EMC Directive 2014 / 30 / EU as follows: "the ability of equipment to operate satisfactorily in its electromagnetic environment without causing electromagnetic disturbances that would be unacceptable to other equipment in the same environment."

[0004] To ensure the required electromagnetic compatibility, electrical and electronic components are encased in shielding housings, for example.

[0005] With HV batteries in motor vehicles, special attention is paid to safety in the event of a thermal event. A thermal event can, for example, be triggered by a short circuit in the HV battery caused by mechanical impact, such as an accident. The short circuit in the HV battery generates considerable heat within the HV battery, leading to the expulsion of flammable gases from the electrodes of the HV battery. In order to discharge these flammable and hot gases from the HV battery in a controlled manner, a so-called cell vent is typically provided. A cell vent is an opening in the HV battery which opens in the event of excess pressure in a cell of the HV battery and through which the excess pressure can be relieved. If a thermal event causes the cell vent to open, the flammable gases must be discharged from the HV battery through the cell vent.For this purpose, openings are typically provided in the housing of the HV battery.

[0006] One problem arises from the fact that, on the one hand, openings must be provided in the housing to discharge the flammable gases from the housing of the HV battery and, on the other hand, the housing should be as closed as possible for electromagnetic shielding.

[0007] A vehicle with an underride guard and an HV battery is known from the generic document US 2009 / 0 242 299 A1 and JP 2016 - 41 586 A. The underride guard has EMC shielding. US 2014 / 0 329 125 A1 also shows a vehicle with an underride guard that has EMC shielding. This is indirectly connected to a housing of an HV battery via the body. DE 10 2021 005 538 A1 discloses an HV battery of a vehicle whose EMC shielding is permeable to venting gases.

[0008] It is an object of the present invention to provide a motor vehicle which does not have the aforementioned disadvantages of the prior art, but rather offers shielding to achieve electromagnetic compatibility without imposing design requirements on the components relating to electromagnetic compatibility.

[0009] This object is achieved by a motor vehicle according to claim 1.

[0010] The motor vehicle according to the invention has an underrun guard. The underrun guard is a part on the floor of the motor vehicle that protects components of the motor vehicle from damage caused by contact with the ground on which the motor vehicle is driven. According to the invention, the underrun guard has EMC shielding. This advantageously makes it possible to electromagnetically shield the motor vehicle downwards using the underrun guard in such a way that components in the motor vehicle meet the specifications relating to electromagnetic compatibility in this direction. Relocating the EMC shielding from the electrical and / or electronic components of the motor vehicle to the underrun guard of the motor vehicle allows for a high degree of flexibility in the design of the electrical and / or electronic components.

[0011] Advantageous embodiments and further developments of the invention can be found in the dependent claims and the description with reference to the drawings.

[0012] According to the invention, the motor vehicle has an HV battery, with the EMC shielding arranged below the HV battery. In this case, the electromagnetic compatibility of the HV battery, as an electrical component of the motor vehicle, is advantageously ensured by the EMC shielding of the underride protection of the motor vehicle. This makes it possible to design the housing of the HV battery in such a way that it meets the design requirements without being restricted by the provision of EMC shielding. The HV battery is preferably a traction battery of the motor vehicle. The motor vehicle is intended, in particular, as an electric vehicle or a hybrid vehicle.

[0013] According to a further preferred embodiment of the present invention, the HV battery is provided with a base plate. At least one opening for degassing the HV battery is provided in the base plate. This advantageously makes it possible, in the event of a thermal event, to discharge hot and flammable gases, which are expelled from the electrodes of the HV battery, from the housing of the HV battery in a controlled manner. For this purpose, it is conceivable for the base plate to comprise a cooling plate for cooling the HV battery. Using the base plate to cool the HV battery enables a space-saving design of the HV battery. This advantageously makes it possible to cool with the base plate, i.e. to provide only one element for this purpose instead of a base plate and cooling plate.The EMC shielding in the underrun protection ensures that the electromagnetic compatibility of the HV battery is still guaranteed despite the openings in the base plate of the HV battery, i.e. in the housing of the HV battery.

[0014] Preferably, the EMC shielding comprises a conductive layer of the underrun protection. The conductive layer within the meaning of the present invention is an electrically conductive layer and can be provided, for example, by using metallic components in the conductive layer. Because the EMC shielding only comprises a conductive layer of the underrun protection, the underrun protection does not have to be completely conductive, which leads to weight savings. It is conceivable that the conductive layer is not arranged over the entire surface of the underrun protection, but that the conductive layer is arranged only in the area of ​​the underrun protection that lies below the HV battery.

[0015] Furthermore, it is preferably provided that the conductive layer comprises a conductive foil and / or a preferably fine-mesh conductive grid and / or a metal-deposited layer. This advantageously makes it possible to provide highly effective EMC shielding in the underrun protection in a very simple design. Inserting a conductive foil, a preferably fine-mesh conductive grid, or a metal-deposited layer is inexpensive and easy to construct. A grid is considered fine-mesh within the meaning of the present invention if the mesh size is less than 2 cm.

[0016] According to a further preferred embodiment of the present invention, the conductive layer is arranged between an upper layer of the underrun protection and a lower layer of the underrun protection. This advantageously makes it possible to protect the EMC shielding from mechanical and chemical influences and thus ensure good electromagnetic compatibility over the long term. Preferably, the upper layer and / or the lower layer is a fiber composite. A fiber composite is typically highly stable and comparatively lightweight. It is also conceivable for the upper layer and / or the lower layer to be laminates, i.e., either laminated together from at least several layers and / or at least laminated onto the EMC shielding.

[0017] It is also conceivable to arrange a core layer between the lower layer and the conductive layer. This provides greater stability and thus greater mechanical resilience of the underrun protection. The core layer can be made of PU (polyurethane) or LFI-PUR, for example. For a core layer made of LFI-PUR, glass fibers are cut and wetted with liquid polyurethane. The wetted glass fibers are formed into the core layer under pressure. This has the advantage that the core layer is extremely strong and meets the highest standards of mechanical stability.

[0018] According to the invention, the HV battery has a battery protective housing, with the EMC shielding being electrically connected to the battery protective housing via a contact. This advantageously integrates the EMC shielding of the underrun protection into another EMC shielding of the battery protective housing, thus ensuring seamless electromagnetic compatibility of the HV battery.

[0019] For this purpose, the invention provides that the contact comprises at least one metallic bushing. An electrical contact is established between the EMC shielding and the battery protection housing via the metallic bushing. For this purpose, the invention provides that the at least one metallic bushing is pressed into the underrun protection and is arranged so as to connect the EMC shielding and the battery protection housing. It is conceivable that a screw, preferably a metallic screw, is screwed through the metallic bushing into the battery protection housing. This creates a secure and electrically conductive, but in particular also detachable, connection between the EMC shielding and the battery protection housing. For example, in the event of damage, the underrun protection can be easily replaced without structurally interfering with the HV battery.

[0020] Alternatively or additionally, according to a further preferred embodiment of the present invention, the contact comprises a metallic strip which is arranged to connect the EMC shielding and the battery protection housing. In particular, it can be provided that the battery protection housing is arranged so as to bear against the metallic strip. It is conceivable that the battery protection housing is screwed to the metallic strip. Preferably, the metallic strip is incorporated between the lower layer and the upper layer of the underrun protection and that the upper layer is removed in the region of the metallic strip. This provides for simple production of the contact via the metallic strip.

[0021] Further details, features, and advantages of the invention will become apparent from the drawings and the following description of preferred embodiments with reference to the drawings. The drawings merely illustrate exemplary embodiments of the invention, which do not limit the scope of the invention. Fig. 1 schematically illustrates a detail of a motor vehicle according to an exemplary embodiment of the present invention with an underrun protection and an HV battery. Fig. 2 schematically illustrates a motor vehicle according to an exemplary embodiment of the present invention.

[0022] Fig. Figure 1 schematically illustrates a detail of a motor vehicle 100 (see Fig.2) according to an exemplary embodiment of the present invention with an underrun protection 1 and an HV battery 3, only partially shown. The underrun protection 1 of the motor vehicle 100 serves to prevent damage to the motor vehicle 100, for example when the floor of the motor vehicle 100 touches the ground while driving or due to objects being thrown up and hitting the floor of the motor vehicle 100.

[0023] The motor vehicle 100 shown here is a hybrid or electric vehicle and has an HV battery 3 as an energy storage device for operating the electric drive motors. The HV battery 3 is arranged as low as possible in the motor vehicle 100, which enables a low center of gravity of the motor vehicle 100. In the embodiment shown here, the HV battery 3 is arranged practically directly above the underrun protection 1 and separated from the underrun protection 1 only by a gap.

[0024] In the event of a thermal event in the HV battery 3, hot, flammable gases may be expelled from the electrodes (not shown) of the HV battery 3. To enable controlled release of these gases, openings 5 ​​are provided in the base plate 4 of the HV battery 3. The gas from the HV battery 3 can flow through the openings 5 ​​into the space between the HV battery 3 and the underrun protection 1 and be discharged from there. In the embodiment shown here, the base plate 4 comprises a cooling plate for cooling the HV battery 3.

[0025] A battery protection housing 9 encloses the AV battery 3 on the sides and top (not shown above). The battery protection housing 9 is designed to ensure electromagnetic compatibility of the HV battery 3 on the sides and top, thus shielding the HV battery 3 against incoming and outgoing electrical and electromagnetic fields. This shielding cannot be fully ensured by the base plate 4, since the openings 5 ​​for degassing the HV battery 3 are provided here.

[0026] In order to ensure the electromagnetic compatibility of the HV battery 3 in all spatial directions, the underrun protection 1 has an EMC shield 2. The EMC shield 2 comprises a conductive layer 6 of the underrun protection 1. For this purpose, it is provided, for example, that a conductive foil and / or a preferably fine-meshed, conductive grid and / or a metallically vapor-deposited layer is arranged in the underrun protection 1. To protect against mechanical and chemical influences, in particular from the outside, it is provided that the underrun protection 1 has an upper layer 7 and a lower layer 8, between which the conductive layer 6 is arranged. The upper layer 7 and the lower layer 8 can each be a fiber composite, for example. It is also conceivable that the upper layer 7 and the lower layer 8 are laminates.

[0027] To increase the stability of the underrun protection 1, a core layer 13 is also provided, which is also arranged between the upper layer 7 and the lower layer 8. In the embodiment shown here, the core layer 13 is arranged between the lower layer 8 and the conductive layer 6. However, it is also conceivable for the core layer 13 to be arranged between the conductive layer 6 and the upper layer 7. The core layer 13 can be made of PU, for example. In particular, it is provided that the core layer 13 is made of LFI-PUR, which gives the underrun protection 1 particularly high stability.

[0028] The EMC shielding 2 is electrically connected to the battery protection housing 9 via a contact 10. For this purpose, in the exemplary embodiment shown here, metallic bushings 11 are pressed into the underrun protection 1 so that they rest against the conductive layer 6 and the battery protection housing 9. The battery protection housing 9 is further screwed through the metallic bushings 11 via metallic screws 12 and thus fastened to the underrun protection 1. The metallic screws 12 establish a further electrical connection between the conductive layer 6 and the battery protection housing 9. This achieves excellent electrical and electromagnetic shielding and thus good electromagnetic compatibility of the HV battery 3.

[0029] Alternatively or additionally, it can be provided that the battery protection housing 9 is arranged adjacent to a metallic band (not shown) and is electrically contacted with the conductive layer 6 via this. List of reference symbols 1 underrun protection 2 EMC shielding 3 HV battery 4 Base plate 5 Opening 6 conductive layer 7 upper layer 8 lower layer 9 Battery protective housing 10 Contacting 11 socket 12 screw 13 core layer 100 motor vehicles

Claims

[1] Motor vehicle (100) comprising an underrun protection (1), wherein the underrun protection (1) has an EMC shield (2), wherein the motor vehicle (100) has an HV battery (3), wherein the EMC shield (2) is arranged below the HV battery (3), wherein the HV battery (3) has a battery protection housing (9), wherein the EMC shield (2) is electrically contacted with the battery protection housing (9) via a contact (10), characterized by that the contact (10) comprises at least one metallic bushing (11), wherein the at least one metallic bushing (11) is pressed into the underrun protection (1) and is arranged connecting the EMC shielding (2) and the battery protection housing (9). [2] Motor vehicle (100) according to claim 1, characterized bythat the HV battery (3) has a base plate (4), wherein the base plate (4) has at least one opening (5) for degassing the HV battery (3), wherein the base plate (4) preferably comprises a cooling plate for cooling the HV battery (3). [3] Motor vehicle (100) according to one of the preceding claims, characterized by that the EMC shielding (2) comprises a conductive layer (6) of the underrun protection (1). [4] Motor vehicle (100) according to claim 3, characterized by that the conductive layer (6) comprises a conductive foil and / or a preferably fine-meshed conductive grid and / or a metallically vapor-deposited layer. [5] Motor vehicle (100) according to one of claims 3 to 4, characterized bythat the conductive layer (6) is arranged between an upper layer (7) of the underrun protection (1) and a lower layer (8) of the underrun protection, wherein the upper layer (7) and / or the lower layer (8) is preferably a fiber composite and / or wherein the upper layer (7) and / or the lower layer (8) are laminates. [6] Motor vehicle (100) according to claim 5, characterized by that a core layer (13), preferably made of PU or LFI-PUR, is arranged between the lower layer (8) and the conductive layer (6). [7] Motor vehicle (100) according to one of the preceding claims, characterized by that a screw (12) is screwed into the battery protection housing (9) through the metallic bushing (11). [8] Motor vehicle (100) according to one of the preceding claims, characterized bythat the contact (10) comprises a metallic band which is arranged to connect the EMC shielding (2) and the battery protection housing (9), wherein it is provided in particular that the upper layer (7) is removed in the region of the metallic band.

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