Method and device for protecting an HV battery in the vehicle floor by means of a damping gel

Abstract

The present invention relates to a method for protecting a high-voltage battery (11), in which a damping gel (14) is arranged in a space (15) between an underride guard (13) and the high-voltage battery, in which a plenum is arranged adjacent to the space, and in which the plenum is connected to the space via a valve unit configured to open when a predetermined pressure within the space is exceeded and to allow damping gel to flow into the plenum, wherein the damping gel in the space is in fluid contact with the valve unit. Furthermore, a device (10) is presented by which the method can be implemented.

Description

[0001] The present invention relates to a method for protecting a high-voltage battery, wherein a damping gel is arranged between the underride guard and the high-voltage battery. Furthermore, a device is presented by which the method can be implemented.

[0002] When an electric vehicle with an underfloor battery or high-voltage (HV) battery located directly above an underride guard drives over obstacles, high forces can act on the underride guard. Especially during rapid impacts perpendicular to the underbody, where the vehicle's inertia comes into play, locally high forces can act on the underride guard. For this reason, the underride guard must be very robust, resulting in high weight and high costs, such as the use of expensive materials (CFRP) or costly manufacturing processes.

[0003] German patent application DE 10 2017 221 345 A1 discloses an underfloor battery and an underride guard for an electric vehicle, wherein a plastic element with cavities is provided on a base plate of the underfloor battery or on the underride guard. The cavities can be filled with air or with a gel.

[0004] German patent application DE 10 2004 031 086 A1 describes a safety device for a motor vehicle. The safety device has at least one energy absorption element.

[0005] From publication DE 101 36 302 A1, an impact damper is known which is designed to serve as a gas spring and as a deformation element.

[0006] Against this background, it is an object of the present invention to propose a method for protecting a high-voltage (HV) battery located near the underride guard of an electric vehicle, in which a damping gel is arranged between the underride guard and the HV battery. The damping gel is intended, on the one hand, to support the HV battery and, on the other hand, to distribute forces occurring perpendicular to the underride guard evenly in the event of an impact. Additionally, deformations of the underride guard caused by the impact and the resulting increased pressure on the damping gel are not to be transmitted to the HV battery; in particular, deformation of the housing of the adjacent HV battery is to be prevented. Furthermore, a device by which the method can be implemented is presented.

[0007] To solve the aforementioned problem, a method for protecting a high-voltage battery is proposed in which a damping gel is arranged in a space between an underride guard and the battery. A plenum is arranged adjacent to this space. The plenum is connected to the space via a valve unit. The valve unit is designed to open when a predetermined pressure within the space is exceeded, allowing damping gel to flow into the plenum. During this process, the damping gel in the space is in fluid contact with the valve unit.

[0008] A value for the predetermined pressure in the space or in the damping gel is determined in test series prior to carrying out the method according to the invention by ensuring that no impairment or damage to the outer casing of the HV battery occurs below or up to this pressure. Thus, the pressure value at which deformation of the outer casing of the HV battery begins is determined, and the predetermined pressure value is set with a safety margin of, for example, 10% below this pressure value.

[0009] The damping gel arranged according to the invention advantageously distributes forces occurring in the gap, for example during a vertical upward impact originating from a road surface irregularity while driving over it and thereby deforming the underride guard, evenly in all directions and thus across all surfaces limiting the gap. This also advantageously provides support to any area of ​​the underride guard that may be deformed by the impact. By distributing the forces, the maximum force value from one impact direction is reduced, and damage to adjacent areas is prevented.

[0010] It is conceivable to produce the damping gel with distilled water and mixed-in diatomaceous earth and antifreeze. Furthermore, air bubbles could be mixed in to equalize volume and increase the damping effect.

[0011] The viscosity of the damping gel is chosen such that, on the one hand, the damping gel is insensitive to movements of a vehicle chassis occurring during driving, and on the other hand, the damping gel can be deflected or easily pushed away in the event of deformations caused by an impact against the underride protection.

[0012] It is conceivable that the valve unit is additionally designed with a return line and a corresponding pressure relief valve to allow damping gel to flow back from the plenum into the space after a prior inflow of damping gel into the plenum and a subsequent pressure drop below the specified pressure. This would allow the space to be refilled with damping gel that had previously flowed into the plenum, even in the event of, for example, a workshop-induced dent in the underride guard – following an impact with deformation.

[0013] In one embodiment of the method according to the invention, a damping gel enclosed in a bag is arranged, the bag being open relative to the valve unit. According to the invention, the damping gel arranged in the space between the underride guard and a base plate of the high-voltage battery is thus advantageously protected from escaping into the surrounding environment in the event of leaks, for example, in the case of a crack in the underride guard. The bag is defined as a media-tight sealable container with a flexible, stretchable cover. The bag should be media-tightly connectable to the valve unit, with the damping gel contained in the bag being in fluid contact with the valve unit, and when the predetermined pressure is exceeded, the damping gel can escape into the plenum through the open valve of the valve unit.

[0014] In a further embodiment of the method according to the invention, at least one compressible filling element and / or at least one compressible compensating element are arranged in the bag in addition to the damping gel. Additionally, air bubbles can be integrated into the bag's outer layer, for example, similar to bubble wrap.

[0015] In a further embodiment of the method according to the invention, the volume of the arranged damping gel is selected to be smaller than the volume enclosed by the gap, thereby forming at least one expansion space. In the remaining expansion space within the gap, the damping gel can expand upon impact from below against the underride guard.

[0016] In a further embodiment of the method according to the invention, the damping gel is formed with at least one property from the following list: electrically non-conductive, frost-resistant, temperature-stable in the operating range of the high-voltage battery, and a conspicuous coloration compared to the surrounding material. An electrically non-conductive damping gel is particularly advantageous in the case of severe damage to the high-voltage battery, so that short circuits are not triggered by the penetration of damping gel into the damaged high-voltage battery. Due to its conspicuous coloration, the damping gel advantageously has a marker function by means of which a leak point can be identified, which, for example, indicates severe damage to the underride guard.

[0017] Furthermore, a device is claimed which comprises an underride guard, a high-voltage battery, a space enclosed by the underride guard and the high-voltage battery, a damping gel, and a plenum connected to the space via a valve unit. The damping gel is arranged in the space between the underride guard and the high-voltage battery. The damping gel is in fluid contact with the valve unit in the space. The valve unit is designed to open when a predetermined pressure within the space is exceeded and to allow damping gel to flow into the plenum.

[0018] It is conceivable that the valve unit of the device additionally has a return line with a corresponding further pressure valve, which is additionally designed to allow damping gel to flow back from the plenum into the space after a previous inflow of damping gel into the plenum and a subsequent pressure drop below the specified pressure.

[0019] In one embodiment of the device according to the invention, a damping gel enclosed in a bag is arranged, wherein the bag is open opposite the valve unit.

[0020] In a further embodiment of the device according to the invention, at least one compressible filling body and / or at least one compressible compensating body are arranged in the bag in addition to the damping gel.

[0021] In a further embodiment of the device according to the invention, the volume of the arranged damping gel is selected to be smaller than the volume enclosed by the space between the layers. This creates at least one expansion space.

[0022] In a further embodiment of the device according to the invention, the damping gel is formed with at least one property from the following list: electrically non-conductive, frost-proof, temperature-stable in the operating range of the HV battery, and with a conspicuous coloration compared to the surrounding material.

[0023] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0024] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0025] The characters are described in a coherent and overarching way. Fig. Figure 1 schematically shows a section of an embodiment of the device according to the invention. Fig. Figure 2 schematically shows a load case during an impact on the embodiment of the device according to the invention. Fig. 1. Fig. Figure 3 schematically shows a valve unit with plenum in a further embodiment of the device according to the invention. Fig. Figure 4 shows pouches containing damping gel in further embodiments of the device according to the invention.

[0026] In the Fig. Figure 1 schematically shows a section 10 of an embodiment of the device according to the invention. The device comprises an underride guard 13, a high-voltage battery 11, a space 15 enclosed by the underride guard 13 and the high-voltage battery 11, and a damping gel 14. The high-voltage battery 11 has a plurality of energy storage cells in its high-voltage interior 12, which must be protected from impacts from the road surface (from below). The damping gel 14 does not completely fill the space 15, but rather areas with a respective expansion space 19 remain free, so that if the underride guard deforms and the space 15 is compressed, the damping gel 14 can expand into the respective expansion space 19.

[0027] In Fig. Figure 2 schematically shows a load case during an impact 26 on the embodiment of the device according to the invention. The impact 26, occurring vertically upwards and originating, for example, during a drive over an unevenness in the road surface, depresses the underride guard 23, so that the space 25 is compressed and the damping gel 24 is also forced into the respective expansion space (reference numeral 19 in Figure 2). Fig. 1) deflects. The damping gel 24 distributes the forces occurring during the impact evenly in all directions, so that the forces act on all surfaces limiting the gap 25. This also provides further advantageous support to the deformed area of ​​the underride guard 23.

[0028] In Fig. Figure 3 schematically shows a valve unit 36 ​​with a plenum 37 in a further embodiment 30 of the device according to the invention. If an impact (reference numeral 26 in Figure 36) occurs, the valve unit 36 ​​is opened. Fig. 2) If a predetermined pressure of the damping gel 34 is exceeded, the valve unit 36 ​​opens a pressure relief valve 38 to the plenum 37 and damping gel 34 flows out of the compressed space (reference numeral 25 in Fig. 2) into the plenum 37. If, as a result, the pressure of the damping gel 34 drops by, for example, 10% below a standard value, a check valve 39 can ensure a return flow of the drained damping gel from the plenum 37. The standard value can, for example, correspond to an atmospheric pressure of 1013 hPa. A drop below this standard value can occur, for example, during the straightening process of a dented area in the underride guard. In this case, refilling the straightened space with damping gel from the plenum 37 is advantageous.

[0029] In Fig.Figure 4 shows two pouches containing damping gel 44 in further embodiments of the device according to the invention. In a first embodiment 41, a plurality of compressible filling elements 43 are arranged in the pouch in addition to the damping gel 44. In a second embodiment 42, several compressible compensating elements 45 are arranged on an inner surface of a pouch shell 49. Each filling element 43 or each compensating element 45 can, for example, be filled with air. Reference symbol list 10 Device 11 Battery housings 12 HV interior 13 Underride protection 14 damping gel 15 space 19 Expansion area 20 stress case 23. Dented underride guard 24 Evasive damping gel 25 Compressed space with force arrows 26 thrust 30 Device with compensating plenum 34 damping gel 35 bags 36 Valve unit 37th Plenary 38 Pressure relief valve to plenum 39 Check valve from plenum 40 bag designs 41 Initial design 42 Second design 43 Compressible packing materials 44 damping gel 45 air cushions compressible 49 bag covers

Claims

[1] Method for protecting an HV battery (11) in which a damping gel (14, 24, 34, 44) is arranged in an intermediate space (15) between an underride guard (13, 23) and the HV battery (11), in which a plenum (37) is arranged adjacent to the intermediate space (15, 25), in which the plenum (37) is connected to the intermediate space (15, 25) via a valve unit (36) which is designed to open when a predetermined pressure is exceeded within the intermediate space (15, 25) and to allow damping gel (14, 24, 34, 44) to flow into the plenum (37), wherein the damping gel (14, 24, 34, 44) in the intermediate space (15, 25) is in fluid contact with the valve unit (36). [2] Method according to claim 1, wherein a damping gel (14, 24, 34, 44) enclosed by a bag is arranged, the bag being open relative to the valve unit (36). [3] Method according to claim 2, wherein at least one compressible filling element (43) and / or at least one compressible compensating element (45) are arranged in the bag in addition to the damping gel (14, 24, 34, 44). [4] Method according to one of the preceding claims, wherein a volume of the arranged damping gel (14, 24, 34, 44) is selected to be smaller than a volume enclosed by the space (15, 25), thereby forming at least one expansion space (19). [5] Method according to one of the preceding claims, wherein the damping gel (14, 24, 34, 44) is formed with at least one property from the following list: electrically non-conductive, frost-proof, temperature-stable in the operating range of the HV battery (11), conspicuous coloration compared to surrounding material. [6] Device comprising an underride guard (13), an HV battery (11), an intermediate space (15, 25) enclosed by the underride guard (13) and the HV battery (11), a damping gel (14, 24, 34, 44), and a plenum (37) connected to the intermediate space (15, 25) via a valve unit (36), wherein the damping gel (14, 24, 34, 44) is arranged in the intermediate space (15, 25) between the underride guard (13) and the HV battery (11), wherein the damping gel (14, 24, 34, 44) is in fluid contact with the valve unit (36) in the intermediate space (15, 25), and the valve unit (36) is configured to open when a predetermined pressure is exceeded within the intermediate space (15, 25). To allow damping gel (14, 24, 34, 44) to flow into the plenary. [7] Device according to claim 6, wherein a damping gel (14, 24, 34, 44) enclosed by a bag is arranged, and wherein the bag is open relative to the valve unit (36). [8] Device according to claim 7, wherein in the bag, in addition to the damping gel (14, 24, 34, 44), at least one compressible filling element (43) and / or at least one compressible compensating element (45) are arranged on an inner surface of a bag shell (49). [9] Device according to one of claims 6 to 8, wherein a volume of the arranged damping gel (14, 24, 34, 44) is selected to be smaller than a volume enclosed by the space (15, 25), whereby at least one expansion space (19) is formed. [10] Device according to one of claims 6 to 9, wherein the damping gel (14, 24, 34, 44) is formed with at least one property from the following list: electrically non-conductive, frost-proof, temperature-stable in the operating range of the HV battery (11), conspicuous coloration compared to surrounding material.

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