Underride protection with at least one degassing channel and traction battery arrangement with such underride protection

Description

[0001] The invention relates to an underride guard for a traction battery of a motor vehicle according to the preamble of claim 1. The invention further relates to a traction battery arrangement with an underride guard.

[0002] An underride guard of this type is designed to protect a traction battery (for electric propulsion), particularly one located in the area of ​​the vehicle's underbody, from external influences. Furthermore, with appropriate design and arrangement, such an underride guard can also be intended to vent the hot gases generated within the traction battery in the event of a fault (e.g., a short circuit) (degassing function). DE 10 2021 103 378 B3 describes a traction battery for a motor vehicle comprising a battery housing and a degassing collector with a degassing chamber located outside the housing's receiving space. The degassing chamber is bounded by the battery housing or its base and a heat shield of the degassing collector.The degassing collector is designed to capture the hot gas released from the battery housing's receiving chamber via a degassing unit and cool it there. It also features an outlet with openings that allow gas exchange between the degassing chamber and the surrounding environment. The heat shield can additionally function as underride protection for the traction battery.

[0003] The closest patent application, DE 10 2020 106 780 A1, describes a battery with a housing base that has a bottom and module holders extending above the bottom, the module holders also functioning as degassing channels. Such a module holder can, for example, be designed as an extruded profile.

[0004] The invention is based on the objective of providing an underride guard for a traction battery that is lightweight and enables effective degassing of the degassing chamber.

[0005] The problem is solved by the underride guard according to claim 1. By the dependent claim, the invention also extends to a traction battery arrangement according to the invention, which includes an underride guard according to the invention. Additional features of the invention are described analogously for both subject matter of the invention in the dependent claims, the following description of the invention (which expressly includes optional and exemplary features), and the figures, whereby this applies to all features, even independently of specific combinations of features.

[0006] The underride guard according to the invention for a traction battery has a shield-like or plate-like base module, which can also be referred to as a shield-like or plate-like base element. This base module is designed to be arranged below a traction battery, forming an intermediate space that at least functions as a degassing chamber.

[0007] According to the invention, the base module has at least one shell element arranged on its upper surface, which forms a degassing channel with a closed cross-section running along the upper surface (of the base module) for the discharge of hot gas from the degassing chamber. Furthermore, this shell element is designed as a plastic-metal composite component and has at least one gas-permeable overflow area within which the flow of hot gas from the degassing chamber into the degassing channel is possible or facilitated. The upper surface of the base module is the side facing the traction battery, which can also be referred to as the inner surface.

[0008] Preferably, the underride guard according to the invention has several such degassing channels, which in particular run parallel to each other. The following explanations apply analogously to an underride guard with only one degassing channel as well as to an underride guard with several degassing channels.

[0009] Preferably, the degassing channel extends longitudinally or transversely over the entire length or width of the underride guard. Preferably, the degassing channel is directly or indirectly connected to the environment at at least one of its ends, and a cover or similar device that opens under overpressure may be provided at that end. If, in the event of a fault, hot gas from the traction battery or battery housing enters the degassing space between the traction battery or battery housing and the base module of the underride guard, this hot gas can flow into or over the degassing channel through the at least one gas-permeable overflow area of ​​the shell element and then escape into the environment via the degassing channel. Due to the expansion that occurs during this process, the hot gas is also advantageously cooled.

[0010] The shell element is not completely gas-permeable, but only partially so, with at least one gas-permeable area designated as the overflow area. Within this overflow area, hot gas from the degassing chamber can flow into the degassing channel. In the relevant section, the degassing channel has a completely closed cross-section with a partially gas-permeable wall, which can also be described as a quasi-closed cross-section. The shell element is otherwise gas-impermeable, i.e., outside the at least one overflow area. This allows for both a rigid and stable design of the shell element and controlled flow guidance of the hot gas.

[0011] The shell element is a plastic-metal composite component. This means that the shell element is made of plastic, in particular thermoplastic plastic (e.g., polypropylene), or fiber-reinforced plastic, in particular fiber-reinforced thermoplastic plastic (e.g., glass fiber-reinforced polypropylene), and at least one metal component, e.g., a metal wire mesh or perforated sheet (su). The plastic used preferably has a V0 fire protection classification. The shell element can therefore be made lightweight and stable. Furthermore, common manufacturing processes, such as injection molding, can be used for its production. Manufacturing can thus be comparatively simple and cost-effective. The shell element can optionally, at least partially, also be made of an organosheet or the like. The shell element preferably has a wall thickness of...-thickness from 1.5 mm to 4.0 mm.

[0012] The shell element is suitably attached to the base module. Preferably, the shell element is bonded or welded to the base module. In particular, it is intended that the shell element and the base module are made of the same plastic, especially thermoplastic (e.g., polypropylene, especially glass fiber reinforced polypropylene), or at least of similar plastics. Preferably, both the shell element and the base module are made of thermoplastic, which offers advantages, among others, for recycling.

[0013] According to the invention, at least one overflow area is formed by an open metal wire mesh (this also includes wire fabric, wire mesh, knitted wire, or the like) or by an open perforated sheet, which refers to a perforated metal sheet. Such a metal wire mesh or perforated sheet has openings (degassing openings) that, on the one hand, allow the hot gas to flow from the degassing chamber into the degassing channel and, on the other hand, serve a particle retention function. The metal wire mesh or perforated sheet is preferably made of steel, i.e., of steel wires or a steel sheet.

[0014] According to the invention, the shell element is designed and manufactured as an injection-molded part, wherein the metal wire mesh or perforated sheet (so) is integrated into the injection-molded part as an overmolded or partially overmolded insert, i.e., as a metal wire mesh or perforated sheet insert. This means that the metal wire mesh or perforated sheet insert is connected to the injection-molded plastic at its edge, or that the metal wire mesh or perforated sheet insert, which may also extend over the entire surface of the shell element, is completely overmolded with plastic, with the exception of the at least one overflow area (which remains open or is not overmolded). If the shell element has several overflow areas, this can be achieved by several overmolded metal wire mesh or perforated sheet inserts or by a single overmolded metal wire mesh or perforated sheet insert.Such a shell element, designed as an injection-molded part and featuring at least one overmolded or overmolded metal wire mesh or perforated sheet insert, is a plastic-metal composite component in injection-molded metal hybrid construction.

[0015] The degassing channel may contain support ribs and / or domes for supporting the shell element. These support ribs and / or domes, preferably made of plastic, particularly thermoplastic, may be part of the base module or the shell element. In particular, the support ribs and / or domes are injection-molded onto the underside of the shell element. However, they may also be designed as separate components and attached to the base module and / or shell element in a suitable manner. The shell element may also be attached via the support ribs and / or domes. Such support ribs and / or domes can also increase the overall stiffness of the underride guard.

[0016] Preferably, the shell element is designed as a trapezoidal or at least trapezoidal-like profile element or as a trapezoidal profile (hereinafter also referred to as a trapezoidal shell element), which has at least two lateral flanks or side surfaces. Such a trapezoidal shell element offers many advantages. Due to its geometric properties, the trapezoidal shell element is very stable and can therefore also function as a spacer between the base module and the traction battery or the battery housing. The connecting web of the trapezoidal profile between the lateral flanks can be designed in such a way that it can simultaneously serve as a contact surface for the traction battery or the battery housing. The connecting web can also include screw elements or similar components for attaching the underride guard to the traction battery or the battery housing.These screw-in elements are primarily embedded or overmolded metallic inserts. Furthermore, the lower extensions of the trapezoidal shell element can be designed as laterally projecting flanges, which can be used as joining flanges, particularly as welding or adhesive flanges, to attach the shell element to the base module.

[0017] Preferably, at least one of the lateral flanks of the trapezoidal profile or shell element, and in particular both lateral flanks, contains at least one overflow area. This overflow area is formed, in particular, by an open metal wire mesh or perforated sheet (as explained above). Such an overflow area can extend over at least half the axial length of the shell element. This overflow area can have constant dimensions along the axial length of the profile or shell element, or it can have variable dimensions, i.e., dimensions that change along the axial length.

[0018] A traction battery arrangement according to the invention comprises at least one traction battery with a battery housing provided for receiving battery modules or the like, and at least one underride guard designed according to the invention, which (forming a degassing chamber) is arranged below the battery housing and is in particular also attached to the battery housing.

[0019] The invention is explained in more detail below with reference to the figures in a non-limiting manner. The features shown in the figures and / or explained below can, even independently of specific combinations of features, be general features of the invention and further develop the invention accordingly. Fig. 1 shows a perspective top view of an underride guard according to the invention with several degassing channels. Fig. 2 shows the cross-section of a degassing channel on the underride guard. Fig. 1 Fig. 3 shows analogous to Fig. 2 the cross-section of the degassing channel at another cross-sectional point with a screw connection point.

[0020] The in Fig. 1 The underride guard 100 shown has a shield-like or plate-like base module 110, which is formed with a circumferential collar-like edge 120. The base module 110 may include stiffening elements and spacers (not shown). The volume enclosed by the base module 110 and the edge 120 forms a degassing chamber for a traction battery (see Fig. 3 ). On the in Fig. 1 Several shell elements 130 are arranged on the visible upper surface of the base module 110, each forming a degassing channel 140 running along the upper surface of the base module 110, with the degassing channels 140 arranged parallel to each other. The degassing channels 140 are designed for the discharge of hot gas H from the degassing chamber, as illustrated for one of the degassing channels 140 by two arrows (H, H'). For this purpose, the shell elements 130 are designed with gas-permeable overflow areas 132, as explained in more detail below.

[0021] Fig. 2 Figure 1 shows an exemplary cross-section of a degassing channel 140. (The following explanations apply analogously to the other degassing channels 140.) The shell element 130 is designed as a trapezoidal profile element with two lateral flanks or side surfaces 131, an upper connecting web or top flange 133, and two lower extensions or bottom flanges 135, which function as joining flanges to which the shell element 130 is, for example, bonded or welded to the base module 110. The trapezoidal shell element 130, together with the base module 110, forms a degassing channel 140, which has a closed, i.e., structurally completely enclosed, trapezoidal cross-section, wherein the channel wall formed by the shell element 130 is partially gas-permeable at the cross-sectional point shown. Within the degassing channel 140, support ribs and / or support domes 150 are arranged to support the shell element 150.The support ribs and / or support domes 150 can also fulfill a flow-guiding function. Support is provided particularly in the overflow areas 132 described below.

[0022] In both lateral flanks 131 of the shell element 130 there are so-called overflow areas 132, which, as gas-permeable wall areas, allow hot gas H to flow from the degassing chamber into the degassing channel 140, as shown in Fig. 1 shown (see arrow H). The shell element 130 is designed as a plastic-metal composite component, wherein the gas-permeable overflow areas 132 are formed from an open (i.e., uncovered) metal wire mesh or open perforated sheet. It is intended that these are metallic inserts (metal wire mesh or perforated sheet inserts) which are integrated into the shell element 130 during injection molding, as explained above.

[0023] As from Fig. 1 As can be seen, the overflow areas 132 in the longitudinal direction of a degassing channel 140 do not extend over the entire length of the trapezoidal shell element 130 and are also designed along the shell element 130 with variable dimensions that change along the axial longitudinal extent of the trapezoidal shell element 130, referring in particular to the diameter in the vertical direction. This achieves a local gas permeability adapted to the overall system. The same can also be achieved by locally adapting the openings (degassing openings). The overflow areas 132 in the two flanks 131 of a trapezoidal shell element 130 can be designed either symmetrically (in the sense of being identical in shape and congruence) or asymmetrically.

[0024] At the in Fig. 3 At the cross-sectional point shown, there is a screw connection point where the underride guard 100 is attached to a battery housing 210 of a traction battery 200 by means of screws. Several such screw connection points are typically provided along the degassing channel 140. In the area of ​​the screw connection point, the base module 110 has a dome-shaped recess 115. The connecting web 133 is formed with a recess 134 in which a screw connection element 136 in the form of a washer or the like is arranged. The screw connection element 136 can also be designed as a so-called (metallic) insert and embedded in the plastic material of the shell element 130. The screw connection is made by means of a threaded bolt 220 on the battery side and a nut 160 screwed onto the underside, thus integrating the shell element 130. The fastening can also be carried out in other ways.

[0025] From the presentation of Fig. 3 It is further evident that the connecting web 133 of the shell element 130 also functions as a contact surface and is designed accordingly, without a protruding screw element 136. Fig. 3 Furthermore, the so-called degassing chamber is recognizable (see reference E).

Claims

1. An underride protection (100) for a traction battery (200), with a shield-like base module (110), which can be arranged under the traction battery (200) with formation of a degassing chamber (E), wherein the base module (110) has at least one shell element (130) arranged on its top, which forms a top-extending degassing channel (140) with a closed cross-section for discharging hot gas (H) from the degassing chamber (E), wherein the shell element (130) is formed as a plastic-metal composite component and has at least one gas-permeable overflow region (132), within which an overflow of the hot gas (H) from the degassing chamber (E) into the degassing channel (140) is possible, characterized in that the shell element (130) is formed as an injection molded part and the overflow region (132) is formed by an open metal wire mesh or by an open perforated plate, wherein the metal wire mesh or the perforated plate is integrated into the injection molded part as an overmolded or partially overmolded insert.

2. The underride protection (100) according to claim 1, characterized in that the shell element (130) is glued or welded to the base module (110).

3. The underride protection (100) according to any one of the preceding claims, characterized in that support ribs and / or support domes (150) are present in the degassing channel (140) to support the shell element (130).

4. The underride protection (100) according to any one of the preceding claims, characterized in that the shell element (130) is formed as a trapezoidal profile element with lateral flanks (131), wherein at least one overflow region (132) is located in at least one lateral flank (131).

5. The underride protection (100) according to claim 4, characterized in that the overflow region (132) is designed with variable dimensions.

6. The underride protection (100) according to claim 4 or 5, characterized in that the connecting web (133) between the lateral flanks (131) is also formed as a contact surface.

7. The underride protection (100) according to claim 6, characterized in that the connecting web (133) has screw elements (136) for securing the underride protection (100) to the traction battery (200).

8. A traction battery arrangement, comprising: - a traction battery (200) with a battery housing (210) to accommodate battery modules; and - an underride protection (100) arranged under the battery housing (210), which is formed according to at least one of the preceding claims.