Battery carrier for an electric vehicle

Abstract

Battery carrier for an electric vehicle comprising a tray (1) with a base (2) and a circumferential wall projecting from the base (2), which is formed by mutually coupled side walls (3) and a circumferential flange (4) projecting outwards from the wall, characterized in that the tray (1) is manufactured as a folded component in one piece and of a single material from a sheet metal blank (6), wherein in at least one corner region (8) of the circumferential wall at least one joining tab (5) is formed on a side wall (3) which overlaps the adjacent side wall (3) and the joining tab (5) and the adjacent side wall (3) are joined together by spot welding with the incorporation of a sealant.

Description

[0001] The present invention relates to a battery carrier for an electric motor vehicle according to the features in the preamble of claim 1.

[0002] Electromobility has become increasingly important in the use of motor vehicles. Electric vehicles are powered predominantly or exclusively by electrical energy. To store this electrical energy in the electric vehicle, batteries, also called accumulators, high-voltage batteries, or traction batteries, are necessary. These batteries have a significant volume and a relatively high weight. To store a sufficient amount of energy, for example, to achieve a range of 300 km on a single charge, these batteries are located in the underfloor area of ​​the vehicle. The batteries themselves are housed in a battery tray, which protects them from external weather conditions and prevents the release of substances contained within the batteries into the environment.

[0003] Battery carriers made of plastic materials, fiber composites, or metallic materials are known from the prior art. These battery carriers are also referred to as "battery trays".

[0004] Such a battery carrier is usually mounted from below on a motor vehicle and extends significantly over a large part of the vehicle's width and also a part of its length.

[0005] A battery tray is characterized by a trough-shaped housing in which multiple batteries are arranged. To ensure sufficient rigidity, a frame made of a hollow profile is arranged around the outside, which can also serve as the surrounding wall of the tray. A battery tray is located in the non-visible underfloor area of ​​the vehicle. The requirements regarding sealing and production tolerances are stringent. However, the manufacturing costs of the battery tray are subject to significant cost pressure.

[0006] The battery tray of a battery carrier is sometimes manufactured as a sheet metal forming component. A generic publication on this topic is US 2016 / 0263639 A1.

[0007] Furthermore, enclosures for energy storage devices are known from JP 2015-116 706 A, US 2012 / 0 244 422 A1 and FR 2 961 443 A1.

[0008] However, problems sometimes arise in the corner areas when bending.

[0009] The object of the present invention is therefore to provide a battery carrier which, with regard to its manufacture and in particular the corner connections produced, is improved compared to battery carriers known from the prior art.

[0010] The aforementioned problem is solved according to the invention in a battery carrier with the features in claim 1.

[0011] Advantageous design variants are described in the dependent claims.

[0012] The battery carrier for an electric vehicle has a tray, hereinafter also referred to as the battery tray. The tray itself has a base and a surrounding wall projecting from the base, which is made of interconnected side walls. A flange projects outwards from the wall. According to the invention, the tray is manufactured as a single-piece, folded or bent component from a sheet of material, wherein at least one joining tab is formed on each side wall in at least one corner region, preferably in all corner regions, overlapping the adjacent side wall. The joining tab and the respective adjacent side wall are joined together by spot welding.

[0013] Preferably, the tub can be manufactured as a folded or bent component. This offers the advantage that a small bending radius can be created between the bottom and the side wall, which is preferably less than 10 times the wall thickness, more preferably less than 5 times, particularly preferably less than 3 times, and especially less than 1.5 times the wall thickness of the sheet metal blank. The bending radius is thus determined between the bottom and the side wall, as well as between the side wall and the joining tab, and therefore between side walls themselves.

[0014] The manufacturing process according to the invention thus makes it possible to achieve a tensile strength Rm greater than 600 MPa when using a sheet metal blank made of a steel alloy.

[0015] Furthermore, when using a mill-hardened aluminum alloy for manufacturing the tub, a tensile strength Rm greater than 250 MPa can be achieved. Since no deep-drawing process is used for manufacturing the tub, materials with higher strengths can be employed. This, in turn, allows for a reduction in wall thickness, which in turn reduces the weight and / or the mass of the raw material used, while maintaining at least the same strength properties.

[0016] The circuit board is a sheet metal board, preferably made of steel or an aluminum alloy. The tray itself is essentially rectangular. The connecting tab is formed integrally and from a single piece of material on each side wall and overlaps a portion or section of the adjacent side wall. It is thermally joined to this portion of the side wall, particularly by weld sealing. In the context of this invention, weld sealing means, in particular, that contaminants or moisture from the outside cannot enter the battery tray, which can optionally be closed with a lid. Furthermore, any liquids leaking from the batteries will not be able to escape from the battery tray. Preferably, an adhesive can also be used additionally or alternatively. A sealant is applied between the connecting tab and the side wall or around the connecting tab.

[0017] The joining tab itself can then, with respect to the interior of the tub, overlap the respective adjacent side wall on the outside or inside. In a particularly preferred embodiment, both side walls adjacent to each other in a corner area have a joining tab, with each joining tab overlapping the opposite adjacent side wall, preferably one joining tab being arranged on the inside and one on the outside.

[0018] The externally projecting flange is connected at each corner by means of a thermally welded joint extending along a projection from a side wall. Alternatively, the flange can also be formed at a 45° angle at each corner by means of a thermally welded joint. The respective flange sections of the adjacent side walls are then connected to each other via this joint.

[0019] Reinforcing struts can be arranged within the tub itself, which can be used in particular to support batteries located within the tub. These reinforcing struts can also be used to transfer crash energy.

[0020] The thermal joining seam is generally designed as a continuous weld. Particularly preferably, in the case of two joining lugs of adjacent side walls, at least one joining seam is coupled with a continuous weld. This continuous weld preferably extends from the flange across the side wall to the bottom. The second joining lug can, for example, also be coupled to the side wall by spot welding.

[0021] Preferably, the side walls and / or the base also have embossings, in particular line-like embossings. These can preferably be introduced into the sheet metal blank before forming or folding. Preferably, the embossings are directed outwards. They can also be directed inwards. Particularly preferably, the embossings are arranged in the area below a reinforcing strut. In particular, the embossing projects into a cavity of a reinforcing strut.

[0022] In an alternative embodiment of the present invention, the previously described tray, also referred to as a folding tray, is not arranged at the bottom but at the top when installed, relative to the vertical direction of the vehicle. The folding tray is thus designed as a hood. The batteries are then preferably positioned on a base plate, and subsequently the folding tray manufactured according to the invention is placed over the batteries on the base plate and connected to the base plate.

[0023] In all the aforementioned design variants, cooling structures can be integrated between the batteries and the base of the tray or hood. For example, separate cooling plates can be arranged on the underside of the batteries. A cooling structure can also be arranged on the side of the base of the tray or hood facing away from the batteries. For example, cooling plates can be applied here.

[0024] To ensure particularly good heat exchange between the underside of the batteries and the base of the tray or cover, a thermal conductor can be incorporated. This can be a film or a thermal paste.

[0025] Further advantages, features, properties, and aspects of the present invention are the subject of the following description. Preferred embodiments are illustrated in the schematic figures. These serve to facilitate understanding of the invention. They show: Fig. 1 a tub according to the invention in perspective view, Fig. 2 a circuit board cut for the manufacture of a tub according to Fig. 1, Fig. 3 an alternative design variant of a bathtub according to Fig. 1, Fig. 4 a circuit board cut for the manufacture of a tub according to Fig. 3, Fig. 5 an alternative design variant of a bathtub Fig. 1, Fig. 6 an alternative design variant of a bathtub Fig. 1, Fig. 7, Fig. 8, Fig. 9 different cross-sectional views through a corner area, Fig. 10 a - c a battery carrier according to the invention in various views, Fig. 11 a sectional view through a flange in the corner area and Fig. 12 an alternative embodiment of the present invention with a hood as a folding tub and Fig. 13 an alternative design variant with a hood as a folding tub.

[0026] In the figures, the same reference symbols are used for identical or similar components, even if a repeated description is omitted for the sake of simplicity.

[0027] Fig. Figure 1 shows a perspective view of a tray 1 of a battery carrier according to the invention. The tray 1 has a base 2 and a surrounding wall, made of interconnected side walls 3. A surrounding flange 4 is arranged projecting from the side walls 3. According to the invention, a joining tab 5 is arranged in a corner region 8 of adjacent side walls 3 and overlaps the right outer side wall (relative to the plane of the image) and is connected by a joint 7. Furthermore, an angle α between the base 2 and the side wall 3 is shown. According to the invention, this angle α can be 90°, since the folding tray is not manufactured like a thermoformed tray. The angle α can also be greater than 90°, but preferably less than 95°, and in particular less than 92°.

[0028] Fig. Figure 2 shows a section of a circuit board 6, from which the following is then made: Fig. The tub 1 shown in Figure 1 is produced by folding or bending operations. If the tub 1 is produced by forming, joining seams 7 are also formed, wherein the joining tabs 5 are materially coupled to the side wall 3 and the adjacent parts of the circumferential flange 4. The joining tabs 5 are according to Fig. 1. The flanges are arranged externally and formed on two opposite side walls 3. Holes 13 can be provided in the flange 4, for example, to later mount a cover. Furthermore, two holes 14 can be provided in the base, for example, to later attach screw connections or for drainage, for example, after painting or KTL coating from the tub.

[0029] Fig. 3 and Fig. 4 show a design variant analogous to Fig. 1 and Fig. 2, with the difference that here, not only does a joining tab 5 of one side wall 3 overlap the adjacent side wall 3 at each produced corner region 8, but rather two joining tabs 5 are formed in each corner region 8. In this illustration, the joining tabs 5 of the respective end-face side wall 3 are arranged on the inside, relative to an interior space 9 of the wall, and the joining tabs 5 of the longitudinal side walls 3 are arranged on the outside, relative to the interior space 9. Joining seams 7 are again formed on the outside to couple the outer joining tabs 5 to the side walls 3. It is particularly preferred that the outermost joining tab 5 is welded tightly to the side wall 3. The innermost joining tabs 5 are spot-welded to the side wall 3. The flange is welded at a 45° angle in the corner regions.

[0030] Fig. 5 and Fig. Figure 6 shows alternative design variants, where, according to Fig. 5 on the inside the joining tab 5 is arranged on the respective side wall 3 and a sealing weld is carried out here in particular.

[0031] According to Fig. 6, the connecting tab 5 is arranged on the outside. Another difference is that... Fig. 5 and Fig. 6 shows that the outer circumferential flange 4 of two adjacent side walls 3 is each formed with a joining seam 7 in a projection of the extension of the respective end-face side wall 3 itself and not as in Fig. 1, Fig. 2, Fig. 3 to Fig. 4 is shown with a 45° angle. The resulting advantage is that the bending radius between the end-face side wall 3 and the flange lies in the parting plane of the flange 4 itself, whereas in the 45° variant according to Fig. 1, Fig. 2, Fig. 3 to Fig. 4 the respective edges of the resulting flange 4 can be positioned better relative to each other.

[0032] Fig. 7, Fig. 8 and Fig. Figure 9 shows different arrangements of the joining tabs 5 according to a sectional view through the corner area 8. Fig. With respect to an interior space 9, the joining tab 5 of an end-face side wall 3 is arranged on the inside opposite the adjacent side wall 3. A joining seam 7 is provided on each of two sides. At least one joining seam is designed as a tight seam, or both joining seams enclose a sealant. In particular, the outer joining seam 7 is designed as a tight weld seam in conjunction with a 45° flange and its continuous joining seam.

[0033] Furthermore, in Fig. Figure 7 shows an inner radius R3 between the joining tab 5 and the side wall 3. This is preferably less than 10 times the wall thickness W of the side wall 3. The same applies to a radius at the bending edge 15 between the side wall 3 and the base 2 (see Figure 7). Fig. 1).

[0034] According to Fig. 8 is the joining tab 5 of a side wall 3, the adjacent side wall 3, relating to an interior space 9 of the tub 1, shown encompassing the outside and coupled with a joining seam 7.

[0035] According to Fig. 9 Two joining tabs 5 are formed, one joining tab 5 on each side wall 3. Each joining tab 5 is angled so that one joining tab 5, relative to an interior space 9, encompasses the upper side wall 3 (relative to the image plane) on its outer side, and the joining tabs 5 of the upper side wall 3 abut the side wall 3 on the left side of the image plane on its inner side. Each of the two joining tabs is coupled to the respective side wall 3 by a joint 7.

[0036] Fig. Figure 10a shows a top view of a battery carrier 10 according to the invention with a respective sectional view according to Fig. 10b and Fig. 10c. The battery carrier 10 has the tray 1 according to the invention, wherein batteries 11 are arranged in the tray 1. Reinforcing struts 12 are also arranged transversely and longitudinally in the tray 1. The batteries 11 can, for example, be attached to the reinforcing struts 12 and, optionally, to the tray 1 itself. The flange 4 is shown circumferentially. The tray 1 can optionally be closed with a cover (not shown in detail), for example, by screwing it to the flange with the inclusion of a seal.

[0037] Fig. Figure 11 shows a cross-sectional view through a flange 4. The right flange 4, relative to the plane of the image, is embossed or offset by a wall thickness W, so that it engages the left flange 4. A resulting bearing surface 17 (see Figure 11) is shown. Fig. 5) The surface for placing a lid is therefore flat. Sealing compound 16 can be applied in a gap.

[0038] Fig. Figure 12 shows an alternative embodiment of the present invention, in which the folding tray is designed as a hood 18. The batteries 11 are initially positioned on a base plate 19. The base plate 19 itself can be a reinforced base plate 19, so that it can support the weight of the batteries 11, which can be up to several hundred kg.

[0039] The batteries 11 are then covered by the folding tray as a hood 18. The hood 18 also has an externally circumferential flange 4, via which it is coupled to the base plate 19. The hood 18 is manufactured as previously described for the tray, in particular in the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10 to Fig. 11 is described. The hood 18 also has a surrounding wall and a base 2. The surrounding wall is formed by the side walls 3.

[0040] Fig. Figure 13 shows an alternative design to the folding tub designed as a hood 18 of the Fig. 12. In the embodiment according to Fig. In the installed position, the electrical connections 20 of the batteries 11 are arranged pointing downwards in the vertical direction of the vehicle. The electrical connections 20 are thus directed towards the floor panel 19. The batteries 11 can therefore be mounted suspended in the hood 18. They can be fixed in the hood 18 to the floor 2 or to the surrounding side walls 3. Reference symbol: 1 tub 2 floors 3 side wall 4 flange 5 wing tabs 6 circuit boards 7 Joining seam 8 Corner area 9 Interior 10 battery holders 11 Battery 12 Reinforcing strut 13 holes 14 holes 15 Bending edge 16 Sealant 17 support areas 18 Hood 19 Floor plate 20 connections α angle R3 inner radius W wall thickness

Claims

[1] Battery carrier for an electric motor vehicle comprising a tray (1) with a base (2) and a circumferential wall extending from the base (2), which is formed by mutually coupled side walls (3) and a circumferential flange (4) extending outwards from the wall, characterized by , that the tub (1) is manufactured as a folded component in one piece and of a single material from a sheet metal blank (6), wherein at least one joining tab (5) is formed on a side wall (3) in at least one corner area (8) of the circumferential wall, which overlaps the adjacent side wall (3) and the joining tab (5) and the adjacent side wall (3) are joined together by spot welding with the incorporation of a sealant. [2] Battery carrier according to claim 1, characterized by that the joining is carried out as welding and as gluing. [3] Battery carrier according to claim 1 or 2, characterized by, that the wing tab (5), with respect to an interior space (9) of the tub (1), overlaps the adjacent side wall (3) on the outside or inside. [4] Battery carrier according to claims 1 to 3, characterized by , that the flange (4) is coupled to two adjacent side walls (3) in a respective corner area (8) in a parallel projected extension of a side wall (3) by means of a thermal joining seam (7) or that the flange (4) is formed by two adjacent side walls (3) in a corner area (8) each at a 45° angle to the outside by means of a thermal joining seam (7). [5] Battery carrier according to claims 1 to 4, characterized by , that the tub (1) is made from a metallic sheet (6), in particular from a steel sheet, preferably from a hardenable steel. [6] Battery carrier according to claims 1 to 5, characterized by, that reinforcing struts (12) are arranged in the tub (1), which are used in particular to accommodate batteries (11) arranged in the tub (1). [7] Battery carrier according to claims 4 to 6, characterized by , that the thermal joining seam (7) is a continuous weld seam. [8] Battery carrier according to any one of claims 1 to 7, characterized by , that the tub (1) is made of high-strength steel, preferably with a tensile strength Rm greater than 600 MPa. [9] Battery carrier according to any one of claims 1 to 8, characterized by , that the base (2) and / or the side walls (3) have indentations for stiffening. [10] Battery carrier according to one of claims 1 to 4 or 6 or 9, characterized by that the tub is made of a roll-hardened aluminum alloy, preferably with a tensile strength Rm greater than 250 MPa.

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