HV battery with coolant drain and underrun protection mounting in a cascaded arrangement

Abstract

In various embodiments, an access area of an HV battery of an electric vehicle is provided, which is arranged in an underbody of the electric vehicle, wherein an underrun protection (6) rests against the HV battery from below, wherein the access area has: a first receptacle (13) for a fastening element (8), by means of which the underrun protection (6) can be fastened from below to an underbody of the HV battery (1); a second receptacle (15) for a closure element (12), by means of which an opening to the interior (2) of the HV battery can be closed, wherein the second receptacle (15) has a smaller diameter than the first receptacle (13); and wherein, viewed from the underbody (1) of the HV battery, the second receptacle (13) is at least partially encompassed by the first receptacle (15) or is arranged behind the first receptacle (13). Furthermore, a corresponding HV battery is provided.

Description

[0001] The present invention relates to an HV battery with coolant drain and underrun protection attachment in a cascaded arrangement.

[0002] To drain operating fluids such as coolant, lubricating oil, and similar fluids from a (battery-electric) vehicle during service, drain openings should ideally be located at the lowest point of the associated fluid circuit. These drain plugs typically only serve the function of opening and closing the fluid circuit, separating the environment from the fluid circuit.

[0003] In new development generations of HV components, especially HV batteries, of vehicles with electrified powertrains, a so-called oil direct cooling is used, in which the fluid circuit is not designed as a separate cooling component, but in which the battery cells are directly surrounded by the cooling medium.

[0004] If the HV battery is located on the vehicle's underbody—which is usually the case—it typically has a separate protective component on its underside, the so-called underrun bar. The underrun bar is designed to protect the HV battery from damage, for example, when driving over foreign objects (curbs, bollards, loose parts on the road, etc.). Recently, the underrun bar can also be used to meet legal requirements for thermal propagation. This requires the gases escaping from the HV battery during a thermal runaway to be directed into the vehicle's surroundings in a targeted and controlled manner. This requires a gas-tight connection between the underrun bar and the HV battery housing that can withstand high temperatures and sudden gas pressure surges.

[0005] Since the HV battery is directly exposed to cooling fluid, and when positioned on the vehicle underbody, this also represents the lowest point of the cooling circuit, a drain plug should be installed on the underside of the HV battery housing. This poses the challenge of ensuring that the required opening in the underride guard remains gas-tight during thermal propagation. Furthermore, the need to remove the underride guard prior to draining the cooling fluid should be avoided. Conversely, the cooling circuit should also be prevented from being opened and causing coolant to leak when removing the underride guard.

[0006] In light of the above conflict situation, the object of the present invention can be seen in providing an HV battery arranged in the vehicle floor that is easy to maintain, in particular without having to remove the underrun protection.

[0007] This object is achieved by the subject matter of the independent patent claim. Further preferred embodiments can be found in the dependent patent claims.

[0008] The present invention is based on the idea of ​​providing, according to a preferred embodiment, a fastening screw for the underrun protection or a thread provided for this purpose on the battery housing and a drain screw for draining a coolant, e.g. a cooling oil, from the interior of the battery or a thread provided for this purpose in a predetermined spatial arrangement. The combination created in this way can be used for the (reversible) opening and closing of the cooling circuit on the HV battery underbody as well as for the (reversible) loosening and fastening of a gas-tight underrun protection. The two functions of draining the coolant and gas-tight fastening of the underrun protection to the underbody of the HV battery are combined locally in such a way that access to the closure element for draining the cooling oil is achieved through the fastening element for attaching the underrun protection, without the latter having to be loosened.Conversely, the fastening element that secures the underrun protection to the underbody of the HV battery can be released without having to loosen or open the locking element. Consequently, both functions—cooling oil drain and underrun protection removal—can be triggered independently of each other.

[0009] According to the invention, an access area for an HV battery of an electric vehicle is provided, which is arranged in an underbody of the electric vehicle, with an underrun guard adjacent to the HV battery from below. The access area can also be understood as an HV battery or an HV battery housing on which an underrun guard is arranged. However, a sub-area of ​​these two components is relevant for the definition of the invention.

[0010] The access area according to the invention has a first receptacle for a fastening element, by means of which the underrun protection can be fastened from below to an underbody of the HV battery, and a second receptacle for a closure element, by means of which an opening to the interior of the HV battery can be closed. The second receptacle has a smaller diameter than the first receptacle and, viewed from the underbody of the HV battery, the second receptacle is at least partially enclosed by the first receptacle or arranged behind the first receptacle. The underrun protection can have a plate which is designed as a crumple zone for energy absorption and is fastened to the HV battery from below.

[0011] When viewed from the side, perpendicular to the direction of insertion of the elements into the respective receptacle, the second receptacle can be positioned in front of the first receptacle, i.e., closer to the external environment than the first receptacle. Both receptacles can have means on their inner sides, e.g., internal threads, for securing the fastening or closure element. If the receptacles are configured as threads, the second thread can be configured as an internal thread when the first thread is configured as an external thread and can be located in the area encompassed laterally by the first thread.

[0012] For the purposes of this description, an access area can be understood as an area on the HV battery that is used to access the HV battery during a scheduled workshop visit, e.g., for an inspection. The access area can also be used for any unplanned repair and maintenance work, e.g., replacing a defective component or repairing accident damage. In all of these cases, draining operating fluids may be necessary, which can be performed at the access area.

[0013] According to further embodiments of the access area according to the invention, the first receptacle can be arranged in a first recess which merges into a second recess which corresponds to the second receptacle. The second recess can be directly adjacent to the first recess. The two recesses can together form a through-opening which has an intermediate step. When the fastening element and the closing element are screwed into their respective sockets, the closing element for draining the cooling oil can be arranged at the end of the fastening element for fastening the undercarriage floor. Both recesses can together form a through-opening which extends through the undercarriage floor and the underbody of the HV battery.

[0014] According to further embodiments of the access region according to the invention, a diameter of the first recess can be larger than a diameter of the second recess. The smaller diameter of the second recess can lead to the intermediate step described in the previous paragraph within the through-opening, which, for example, accommodates the two threads.

[0015] According to further embodiments of the access area according to the invention, the first receptacle can have a first thread and / or the second receptacle can have a second thread. Based on this embodiment, the second thread can preferably be arranged concentrically to the first thread.

[0016] According to further embodiments of the access area according to the invention, the first receptacle and the second receptacle can be arranged in a material block which is fastened in an opening in the underbody of the HV battery by means of at least one weld seam. The material block can be a bushing or a weld nut which is used to provide the receptacles, e.g. in the form of threaded lengths, at the required height. This is particularly useful when the wall thickness of the HV housing is small. The material block can be fastened to the battery housing by means of at least one weld seam running all the way around on one side, preferably by means of two weld seams running all the way around on both sides.

[0017] According to further embodiments of the access area according to the invention, the underrun protection can have an opening in the area of ​​the access area. The first receptacle and the second receptacle can be exposed through the opening, provided the fastening and closing elements are not inserted.

[0018] According to further embodiments of the access area according to the invention, a sealing material can be arranged around the opening between the underbody of the HV battery and the underrun protection, thereby sealing the area between the underbody of the HV battery and the underrun protection in a gas-tight manner towards the opening. The sealing material can, for example, be in the form of a sealing disc or a foam seal and can be arranged around the material block or around the through-opening in which the two threads are located.

[0019] According to further embodiments of the access area according to the invention, it can further comprise the closure element. The closure element can preferably comprise a drain plug, which is screwed into the second receptacle, which is then configured as a thread, wherein the drain plug preferably comprises a grub screw. This allows the space required for the screw head to be saved, so that the drain plug has the smallest possible outer diameter.

[0020] The drain plug can also have a force application point for a tool and a circumferential groove for a sealing element (e.g., an O-ring). Furthermore, an axial stop can be provided in the recess for the drain plug, which can ensure a structurally defined screw-in depth.

[0021] According to further design screws, the drain plug can have a conical thread around which, for example, Teflon tape can be wrapped when tightening in order to obtain a seal.

[0022] According to further embodiments of the access area according to the invention, it can further comprise the fastening element. The fastening element can preferably comprise the fastening screw, which is screwed into the second receptacle, which is then designed as a thread, and has a through-hole (e.g., a through-bore) in its shaft. The drain plug can be opened and closed with a tool through the through-hole and removed as needed. The through-hole provides access to the drain plug located behind the fastening screw.

[0023] According to further embodiments of the access area according to the invention, the through-opening can be closed with a closure cap on the outside of the access area. The closure cap serves to prevent the ingress of dirt.

[0024] According to further embodiments, the fastening element and / or the closure element may, in deviation from the aforementioned embodiment, not be designed as a screw, but rather be realized by means of another element which is based on a different operating principle, e.g. as a nut, bolt with interference fit, bayonet closure, plug made of plastic.

[0025] According to the invention, an HV battery is further provided, in particular for a vehicle, comprising an HV battery housing in which at least one battery cell is arranged, and an underrun protection which is fastened to the underbody of the HV battery, wherein the HV battery has an access area according to one of the previously described embodiments.

[0026] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0027] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings. In Fig. 1 illustrates an embodiment of an access area according to the invention. In this embodiment, the first and second receptacles are designed as threads. Accordingly, in this embodiment, the fastening element is designed as a fastening screw and the closure element as a closure screw. As already explained, threads and corresponding screws represent a suitable embodiment of the two receptacles, including the fastening and closure elements, but are not intended to limit them in this respect.

[0028] The access area encompasses an area around the underside 1 of the HV battery housing, to which an underrun protection 6 is attached from below. The access area is shown here with the associated screws, i.e., the fastening screw 8 and the drain plug 12. This state corresponds to the state after assembly of the vehicle, in which it can also be delivered to a customer.

[0029] In the access area, a first thread 13 is arranged, in which the fastening screw 8 is received, by means of which the underrun protection 6 is fastened from below to an underbody 1 of the HV battery. In the access area, a second thread 15 is also arranged, in which the drain screw 12 is received, by means of which an opening to the interior 2 of the HV battery is closed. The second thread 15 has a smaller diameter than the first thread 13. Viewed from the underbody 1 of the HV battery, the second thread 15 is encompassed by the first thread 13. Viewed from the side, the second thread 15 is arranged behind the first thread 13. The first thread 13 is machined here in the inner wall of a first recess 14 and the second thread is machined in an inner wall of an adjoining second recess 16.The first recess 14 and the second recess 16 form a through-opening through the material block 4.

[0030] The underside or underbody 1 of the HV battery housing serves to separate the internal volume 2 of the HV battery, through which the cooling medium flows, from the vehicle environment 3. The battery housing can typically be made of metal. In the case of thin walls, the integration of a drain opening for the cooling medium requires a local thickening of the material in order to provide the necessary threads and sealing points at the required height. For this reason, in the example shown, a material block 4, such as a bushing or a weld nut, is arranged in the underbody 1 of the HV battery. In this case, the material block 4 is attached to the underbody 1 of the HV battery housing via weld seams 5 running around both sides.

[0031] The underrun protection 6 is attached to the battery underbody 1. This is recessed in the area of ​​the drain opening, for example, with a circular cutout. To seal this cutout against gases in the event of thermal propagation, a circumferential sealing element 7, such as a circumferential foam seal, is inserted into the gap between the underbody 1 and the underrun protection 6. A fastening screw 8 is provided to press this foam seal against the battery underbody 1 with the required preload for gas tightness. It has an extra-wide collar to enable the most flat pressing of the assembly comprising the underrun protection 1, the sealing element 7, and the battery housing.

[0032] In the example shown, the fastening screw 8 is screwed into the material block 4. The fastening screw 8 also has a through-hole 9 in the form of a concentric bore, through which, when screwed in, access to the drain screw 12 located behind it is possible. This can, as in Fig. 1, it is designed as a grub screw for the smallest possible outer diameter. This allows it to be opened / closed and removed with a tool through the through-hole in the fastening screw 8. Furthermore, the fastening screw 8 in the example shown has an internal force application 10 for a tool, by means of which it can be screwed in and out of the first thread 13. To protect the through-hole from the ingress of dirt, a closure cap 11 is inserted into it.

[0033] The drain plug 12, which is located in the Fig. 1, is screwed into the second recess 16, also has a force application point for a tool. Furthermore, it can have a recess for a sealing element (e.g., an O-ring). The drain plug can also have an axial stop in order to achieve a structurally defined screw-in depth. As an alternative to such a sealing element, the sealing of the oil chamber or interior 2 of the HV battery by the drain plug 12 can also be ensured by a conical thread with Teflon tape (in Fig. 1 not shown graphically).

[0034] In Fig.Figure 1 shows the access area occupied by the two screws 8 and 12. An electric vehicle with the HV battery can be delivered in this state. After removing the cap 11, either the drain screw 12 can be removed separately to drain the coolant from the interior 2 or the fastening screw 12 can be removed separately to remove the underrun protection 6. This allows for separate performance of both service procedures, thus enabling cost-effective repairs / maintenance. There are no disadvantages in complying with legal requirements regarding thermal propagation of the HV battery, as the assembly is gas-tight.

Claims

[1] Access area of an HV battery of an electric vehicle, which is arranged in an underbody of the electric vehicle, wherein an underrun protection (6) is applied to the HV battery from below, wherein the access area comprises: a first receptacle (13) for a fastening element (8), by means of which the underrun protection (6) can be fastened from below to an underbody of the (1) HV battery; a second receptacle (15) for a closure element (12), by means of which an opening to the interior (2) of the HV battery can be closed, wherein the second receptacle (15) has a smaller diameter than the first receptacle (13); and wherein, viewed from the underbody (1) of the HV battery, the second receptacle (13) is at least partially encompassed by the first receptacle (15) or is arranged behind the first receptacle (13). [2] Access area according to claim 1, wherein the first receptacle (13) is arranged in a first recess (14) which merges into a second recess (16) which corresponds to the second receptacle (15). [3] Access area according to claim 2, wherein a diameter of the first recess (14) is larger than a diameter of the second recess (16). [4] Access area according to one of 1 to 3, wherein the first receptacle (13) has a first thread and / or the second receptacle (15) has a second thread; wherein the second thread (15) is preferably arranged concentrically to the first thread (13). [5] Access area according to one of claims 1 to 4, wherein the first receptacle (13) and the second receptacle (15) are arranged in a material block (4) which is fastened in an opening in the underbody (1) of the HV battery by means of at least one weld seam (5). [6] Access area according to one of claims 1 to 5, wherein the underrun protection (6) has an opening in the area of the access area. [7] Access area according to claim 6, wherein a sealing material (7) is arranged between the underbody (1) of the HV battery and the underrun protection (6) around the opening, whereby the area between the underbody (1) of the HV battery and the underrun protection (6) is sealed gas-tight towards the opening. [8] Access area according to one of claims 1 to 7, further comprising: the closure element (12). [9] Access area according to one of claims 4 to 8, as long as it refers back to claim 4, wherein the closure element (12) has a drain screw which is screwed into the second thread (15), wherein the drain screw (12) preferably has a grub screw. [10] Access area according to one of claims 1 to 9, further comprising: the fastening element (8). [11] Access area according to one of claims 4 to 10, when dependent on claim 4, wherein the fastening element (8) comprises a fastening screw which is screwed into the first thread (13) and has a through opening (9) in its shaft. [12] Access area according to claim 11, wherein the passage opening is closed with a closure cap (11) towards the outside of the access area. [13] HV battery, comprising: an HV battery housing in which at least one battery cell is arranged; an underrun protection (6) which is attached to the underbody of the HV battery; wherein the HV battery has an access area according to one of claims 1 to 12.

Images