Traction battery of a motor vehicle, method for manufacturing a traction battery, motor vehicle

Abstract

A traction battery (1) of a motor vehicle (100) comprising a battery housing (2) is proposed, wherein the battery housing (2) has a top plate (3), characterized in that the top plate (3) is provided with a weakening point (4). Furthermore, a method for manufacturing a traction battery (1) and a motor vehicle (100) are proposed.

Description

[0001] The present invention relates to a traction battery for a motor vehicle with a battery housing. The present invention further relates to a method for manufacturing a traction battery and a motor vehicle.

[0002] Motor vehicles with an electrified powertrain have an electric motor, power electronics to supply the electric motor, and a traction battery to provide electrical energy.

[0003] The traction battery is a component of the powertrain that receives special attention in safety considerations. If a local short circuit occurs in the traction battery, for example due to mechanical damage in an accident or contamination of the separator, the short-circuit current heats the immediate vicinity of the fault due to the internal resistance of the traction battery. This causes flammable gases to be expelled, leading to a self-reinforcing, heat-generating process known as thermal runaway. If the thermal runaway reaches and spreads to neighboring cells, a chain reaction can occur. This is referred to as thermal propagation.

[0004] To minimize damage from the expelled hot gases, degassing channels are typically present on the exterior or within the battery casing of the traction battery. These channels allow the hot gases to be vented from the battery in a controlled manner, and during this process, they are cooled and filtered. To prevent an opening between the interior and exterior of the battery casing from forming through the degassing channels, the casing is typically sealed at the interface with a rupture element. Such rupture elements are mounted on openings in the battery casing and seal them. If the pressure inside the traction battery increases due to thermal runaway, the rupture elements break, releasing the opening.

[0005] It is therefore an object of the present invention to provide a traction battery, a method for manufacturing a traction battery and a motor vehicle which makes it possible to do without additional bursting elements of the traction battery and allows for simple and cost-effective manufacturing of the traction battery.

[0006] This problem is solved by a traction battery according to claim 1. This problem is further solved by a method according to claim 9 and a motor vehicle according to claim 10.

[0007] The traction battery according to the invention is a traction battery for a motor vehicle. The battery housing of the traction battery has a top plate. The top plate is a cover that closes the battery housing. According to the invention, the top plate is provided with a weakening point. The weakening point is a location where the structure of the top plate is intentionally weakened. This advantageously makes it possible to define a location on the top plate where, at a certain overpressure inside the traction battery, the top plate ruptures, thus providing an opening for the controlled release of gases from the battery housing. Additional rupture elements and the associated modifications to the structure of the battery housing are therefore unnecessary apart from the top plate.This saves space on the one hand, and on the other hand, the weak point of the battery housing can be taken into account directly during the production of the top plate, making the production of the traction battery simpler and more cost-effective.

[0008] The weakening point is particularly preferably designed in the form of a closed curve. This advantageously allows a defined opening to be created at the weakening point when the head plate is torn open, which corresponds to the interior of the closed curve.

[0009] Advantageous embodiments and further developments of the invention can be found in the dependent claims and in the description with reference to the drawings.

[0010] According to a preferred embodiment of the present invention, the head plate has a thinner wall at the weakening point than elsewhere, the weakening point preferably comprising a V- or U-shaped recess in the head plate. This advantageously achieves a structural weakening that allows for controlled tearing of the head plate. It is conceivable that the V- or U-shaped recess is arranged on the inside of the head plate. However, it is also conceivable that the V- or U-shaped recess is arranged on both the inside and the outside of the head plate.

[0011] It is particularly preferred that the weakened area is created by material removal, preferably by laser cutting and / or engraving. This allows the head plate to be manufactured with the weakened area very cost-effectively. Furthermore, laser cutting and engraving are very precise, which allows the tensile strength of the weakened area to be correctly adjusted.

[0012] Alternatively, it is particularly preferred that the weakened area is produced by non-material-removing forming, preferably by stamping and / or cup drawing and / or deep drawing and / or thermoforming. This advantageously allows the weakened area to be introduced directly during the production of a three-dimensional structure on the head plate. For example, it is conceivable that an area of ​​the head plate is highlighted or recessed by cup drawing or deep drawing. In this process, the material thickness is reduced in the highlighted or recessed area, respectively, and at the edges of the highlighted or recessed area.

[0013] According to a further preferred embodiment of the present invention, the head plate comprises a first material and a second material. The first material has a higher tensile strength than the second material. The weakened area contains a higher proportion of the second material than the other areas of the head plate. This advantageously makes it possible to produce the weakened area while maintaining a constant wall thickness.

[0014] This eliminates the need for cutouts on the headstock, resulting in a smooth surface.

[0015] A particularly preferred embodiment of the present invention is one in which the head plate has ribs and / or beads for stiffening the head plate away from the weakening point. This advantageously improves the mechanical strength of the head plate away from the weakening point. It is conceivable that the weakening point is created by the absence of ribs and / or beads for stiffening the head plate.

[0016] According to a further preferred embodiment of the present invention, the head plate is made of aluminum and / or of a plastic, wherein the head plate is preferably made of aluminum or wherein the head plate is preferably made of plastic. Aluminum and plastic advantageously enable very lightweight head plates, which are highly suitable for controlled tearing at the weak points.

[0017] In particular, the top plate is designed to be screwed to the battery housing. This ensures a strong connection between the top plate and the rest of the battery housing. It is conceivable that a seal is provided between the top plate and the rest of the battery housing, so that hot gases from inside the battery housing escape only through the opening created at the weak point when the top plate is ripped open.

[0018] A further object of the present invention for solving the problem formulated at the outset is a method for manufacturing a traction battery, wherein a battery housing with a top plate is provided and the top plate is provided with a weakening point. In particular, it is provided that the traction battery is a traction battery according to the invention.

[0019] Another object of the present invention for solving the problem formulated at the outset is a motor vehicle comprising a traction battery according to the invention.

[0020] All details, features and advantages previously disclosed in connection with the traction battery according to the invention also relate to the method according to the invention and to the motor vehicle according to the invention.

[0021] Further details, features, and advantages of the invention will become apparent from the drawings and from 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 inventive concept. Fig. Figure 1 schematically illustrates a traction battery according to an exemplary embodiment of the present invention. Fig. Figure 2 schematically illustrates a head plate of a traction battery according to a further exemplary embodiment of the present invention. Fig. Figure 3 shows a schematic, cross-sectional view of a head plate of a traction battery according to a further exemplary embodiment of the present invention. Fig. Figure 4 shows a schematic, cross-sectional view of a head plate of a traction battery according to a further exemplary embodiment of the present invention. Fig. Figure 5 schematically illustrates a head plate of a traction battery according to a further exemplary embodiment of the present invention. Fig. Figure 6 schematically illustrates a motor vehicle according to an exemplary embodiment of the present invention.

[0022] Fig. Figure 1 schematically illustrates a traction battery 1 according to an exemplary embodiment of the present invention. The traction battery 1 is a traction battery 1 of a motor vehicle 100 (see Figure 1). Fig. 6).

[0023] The traction battery 1 has a battery housing 2. A top plate 3 is screwed to the top of the battery housing 2 and closes the battery housing 2.

[0024] To seal the interior of the battery housing 2, a seal (not shown) is provided on the top plate 3. This ensures that no dust or water can penetrate the battery housing 2.

[0025] In rare cases, thermal propagation can occur in battery 1, during which hot gases are expelled. It is crucial to vent these hot gases from battery housing 2 in a controlled manner, for example, by cooling and filtering them. To provide an opening in battery housing 2 that allows the high-pressure gases to escape when necessary, the top plate 3 has weak points 4. These weak points 4 are locations in the top plate 3 whose structural integrity fails when the maximum internal pressure of the battery housing 2 is reached, causing the top plate 3 to rupture. This rupture of the top plate 3 provides a defined path for the hot gases to escape from inside battery housing 2.

[0026] In the embodiments shown here, the weakening points 4 are designed as closed curves, so that the part enclosed by the weakening points 4 breaks away during thermal propagation.

[0027] Fig. Figure 1 shows weak points 4, which are created by cup drawing or deep drawing. In contrast to deep drawing, no material flows in during forming, so the wall thickness at the weak points 4 is reduced. The forming process has resulted in a bulge where, depending on the technique used, either the side walls or the base of the bulge are thinner than the rest of the end plate 3.

[0028] Fig. Figure 2 shows an alternative. The headplate 3 is shown, in which the weakening points 4 are incorporated by means of punching, laser cutting or engraving.

[0029] This is also in the Fig. Figure 3 shows the head plate 3 in a cross-sectional view. The V-shaped recesses at the weakening points 4, which were created by material removal during laser or engraving or by displacement during stamping, are clearly visible.

[0030] Another alternative to this is in Fig. 4 shown. Fig. Figure 4 also shows a cross-sectional view of the head plate 3, which in this case is manufactured using two different materials. The first material 3.1 of the head plate 3 has a higher tensile strength than the second material 3.2 of the head plate 3. The weakened areas 4 are formed by the fact that the proportion of the second material 3.2 is significantly higher in these areas than elsewhere.

[0031] Fig.Figure 5 shows a head plate 3, which is stiffened by ribs 5 or beads. The ribs 5 or beads are only arranged away from the weakening point 4, so that the weakening point 4 is significantly less stiff and consequently tears open more readily under overpressure than the areas of the head plate 3 that surround the weakening point 4. Reference symbol list 1 traction battery 2 battery cases 3 Head plate 3.1 First material 3.2 second material 4. Weak point 5th rib 100 motor vehicles

Claims

[1] Traction battery (1) of a motor vehicle (100) comprising a battery housing (2), wherein the battery housing (2) comprises a top plate (3), characterized by , that the head plate (3) is provided with a weakening point (4). [2] Traction battery (1) according to claim 1, characterized by , that the head plate (3) has a lesser wall thickness at the weakening point (4) than away from the weakening point (4), wherein the weakening point (4) preferably comprises a V- or U-shaped recess in the head plate (3). [3] Traction battery (1) according to claim 2, characterized by , that the weakening point (4) is produced by material removal, preferably by laser and / or engraving. [4] Traction battery (1) according to claim 2, characterized by, that the weakening point (4) is produced by non-material-removing forming, wherein the weakening point (4) is preferably produced by punching and / or cup drawing and / or deep drawing and / or thermoforming. [5] Traction battery (1) according to any one of the preceding claims, characterized by , that the head plate (3) has a first material (3.1) and a second material (3.2), wherein the first material (3.1) has a higher tensile strength than the second material (3.2), wherein the weakening point (4) has a higher proportion of the second material (3.2) than the other parts of the head plate (3). [6] Traction battery (1) according to any one of the preceding claims, characterized by , that the head plate (3) has ribs (5) and / or beads for stiffening the head plate (3) away from the weakening point (4). [7] Traction battery (1) according to any one of the preceding claims, characterized bythat the head plate (3) comprises aluminium and / or that the head plate (3) comprises a plastic, wherein the head plate (3) is preferably made of aluminium or wherein the head plate (3) is preferably made of plastic. [8] Traction battery (1) according to any one of the preceding claims, characterized by , that the top plate (3) is screwed to the battery housing (2). [9] Method for manufacturing a traction battery (1) wherein a battery housing (2) is provided with a top plate (3) wherein the top plate (3) is provided with a weakening point (4). [10] Motor vehicle (100) comprising a traction battery (1) according to one of the claims.

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