Housing part, battery housing, and traction battery

Abstract

The invention relates to a housing part (10), in particular a housing cover (10), for a battery housing (100) of a traction battery (200) of an electrically operatable vehicle for connecting to a second housing part (12) of the battery housing (100). The housing part comprises a structure made of multiple layers (20, 22, 24, 26) with different materials, at least comprising an outer layer (20) made of plastic, a metal layer (22) made of steel, and a structure layer (26) made of a structure material, wherein the outer layer (20) and the metal layer (22) are connected over a large surface area, and the structure layer (26) covers at least one part of the surface area of the outer layer (20) and / or the metal layer (22). An intermediate layer (24) is arranged between the structure layer (26) and the combination of the outer layer (20) and the metal layer (22). The invention additionally relates to a battery housing (100) for a traction battery (200) and to a traction battery (200) for an electrically operatable vehicle.

Description

[0001] Housing part, battery housing and traction battery

[0002] The invention relates to a housing part, in particular a housing cover, for a battery housing of a traction battery of an electrically operated vehicle, a battery housing for a traction battery and a traction battery for an electrically operated vehicle.

[0003] Housing covers or large-surface parts of traction batteries must be stabilized via additional attachment points due to potentially disruptive vibration behavior and fatigue strength. This results in significant testing effort to ensure leak tightness and corrosion resistance. Reinforcing beads result in additional installation space being lost within the battery.

[0004] DE 10 2020 101 039 A1 discloses a housing cover for a battery housing of a traction battery of an electrically driven motor vehicle, which housing cover serves to be placed on a lower housing part of the battery housing. The housing cover has a covering layer for closing off, in particular for sealing, an interior space of the battery housing. The interior space is designed to accommodate at least one battery cell. Furthermore, the housing cover has a protective layer that overlaps the covering layer at least in some areas to withstand thermal stress caused by heat exposure to the housing cover during emergency degassing of the at least one battery cell.The protective layer is mechanically connected to the cover layer in connection areas and is arranged at a distance from the cover layer in protection areas, forming a gap intended to increase a thermal contact resistance between the protective layer and the cover layer.

[0005] An object of the invention is to provide an improved housing part, in particular an improved housing cover, for a battery housing of a traction battery of an electrically operated vehicle, which is space-saving and can be manufactured cost-effectively.

[0006] A further object is to provide a battery housing for a traction battery of an electrically operated vehicle with such an improved housing part.

[0007] A further object is to create a traction battery for an electrically operated vehicle with such a battery housing.

[0008] The above-mentioned objects are solved by the features of the independent claims.

[0009] Advantageous embodiments and advantages of the invention emerge from the further claims, the description and the drawing.

[0010] According to one aspect of the invention, a housing part, in particular a housing cover, for a battery housing of a traction battery of an electrically operated vehicle is proposed, for connection to a second housing part of the battery housing, having a structure made of several layers of different materials. The housing part comprises at least one outer layer made of a plastic, a metal layer, in particular made of steel, and a structural layer made of a structural material, wherein the outer layer and the metal layer are connected over a large area. The structural layer covers at least part of a surface of the outer layer and / or the metal layer. An intermediate layer is arranged between the structural layer and the combination of outer layer and metal layer.

[0011] The proposed housing part, in particular the housing cover, for a traction battery consists of several layers with different properties.

[0012] The outer layer forms a corrosion protection layer for the housing part, as well as thermal insulation and stone chip protection for traction batteries in the underbody area of ​​a vehicle.

[0013] This outer layer is firmly bonded to the metal layer, which can be designed as a steel insert. This metal layer can, for example, be overmolded with the housing part's material during the manufacturing process or cast into the material. The metal layer protects the interior of the traction battery against point loads in the vertical Z-direction of the vehicle, as the battery can deform significantly and does not crack under load. This ensures that the housing part is leak-tight. The metal layer also protects against the housing part burning through in the event of a thermal event in a battery cell from a cell module. The metal layer also forms an electromagnetic shield. This eliminates the need for additional metallic covers for improved electromagnetic compatibility (EMC), and saves installation space.

[0014] An intermediate layer is placed on the metal layer, which serves as a connecting layer between the metal layer or the combination of outer layer and metal layer and an overlying structural layer arranged at a distance towards the interior of the housing part.

[0015] The structural layer is made of a material with a higher modulus of elasticity, such as steel and / or aluminum and / or fiber-reinforced plastic, and forms a so-called upper chord in the layered structure. Bending or torsional forces are transmitted through the upper or lower layer, respectively. A material with a high modulus of elasticity can be advantageously used here.

[0016] The stresses on the housing cover in a high-voltage battery are caused by vibrations during vehicle operation, for example, by air currents that create negative pressure, or vibrations triggered by the road surface, but also by contact with or driving over large objects, as well as by the gas pressure that develops in the high-voltage battery during a thermal event. Large-surface parts, such as housing covers in high-voltage vehicle batteries, which are very easily subject to vibration, usually require additional screw points to support them, which can be eliminated with the proposed housing component.

[0017] With the inventive layered construction of the housing part, in particular the housing cover, vibrations and / or unpleasant noises can be reduced or completely eliminated. This reduces the stresses on the materials. The multi-layer structure makes it possible to span a housing cover over a large area without additional support for this area. The loads are absorbed by the formed upper chord layer. The loads in the so-called lower chord are transmitted via the outer cover layer. An intermediate structure arranged between the outer layer with the metal layer and the structural layer can serve to distribute the load.

[0018] If the casing is subjected to bending stress, for example, due to vibrations during vehicle operation, impact with an object, or gas pressure during a thermal event, the top layer is subjected to tensile stress. This is where the highest forces occur. The same forces occur in the lowest layer, the bottom chord, but in a different direction than compressive forces. An intermediate structure is subjected to little to no stress. Therefore, a high-performance top chord and bottom chord, for example, made of steel, ensure the high load-bearing capacity of the structure.

[0019] The combination of multiple layers made of different materials enables improved inherent rigidity of large-surface parts. Structural layers eliminate the need for connection points for large-surface components and ensure even load distribution when applied at specific points. For example, forces in the vertical Z-direction of the component are distributed over a large area during proper installation in a vehicle, so that only a reduced surface load acts on the interior of the battery. The integration of multiple requirements into the individual layers, such as the formation of gas channels and the presence of insulating properties, is advantageously possible.

[0020] According to an advantageous embodiment of the housing part, the metal layer can be integrated into the outer layer. In particular, the metal layer can be overmolded with the material of the outer layer or cast into the material of the outer layer. This allows for a firm connection or integration of the metal layer into the outer layer, which can be manufactured cost-effectively using common plastic manufacturing processes.

[0021] According to an advantageous embodiment of the housing part, the structural layer can be formed from a material with a higher modulus of elasticity than the modulus of elasticity of the combination of outer layer and metal layer. In particular, the structural layer can comprise at least steel and / or aluminum and / or fiber-reinforced plastic. In particular, the structural layer can be formed from steel and / or aluminum and / or fiber-reinforced plastic. In this way, bending forces or torsional forces can advantageously be conducted through the upper layer or lower layer of the multi-layer structure of the housing part.

[0022] Together with the steel insert of the outer layer, this creates a structural upper and lower chord structure. This significantly increases the rigidity of the housing component and significantly reduces overall vibrations. This makes it possible to avoid any bolted support connections and the associated complex process steps.

[0023] According to an advantageous embodiment of the housing part, the intermediate layer can comprise a molded foam. In particular, the intermediate layer can comprise at least one of a plastic foam, in particular polyurethane foam, folding cores made of paper, glass fabric, or textiles.

[0024] The molded foam intermediate layer can be placed on top of the steel insert of the outer layer. The molded foam can advantageously be made of a material that distributes the force evenly when loaded in the Z direction, reducing the point load on a cell module located inside the battery housing. The intermediate layer can be manufactured, for example, by foaming or gluing it onto the outer layer with the steel insert.

[0025] According to an advantageous embodiment of the housing part, the intermediate layer can have channels for discharging fluids, in particular gases. Gases generated during a thermal event, for example, can be discharged via the channels.

[0026] According to an advantageous embodiment, the housing part can further comprise an electrical insulation layer made of an electrically insulating material, in particular at least one of plastic, ceramic, or fiber-plastic composite material. The insulation layer can advantageously be applied as the innermost layer of the battery housing and used as an electrical insulator for a cell module mounted above it.

[0027] According to an advantageous embodiment of the housing part, the metal layer can be firmly bonded to the intermediate layer and / or the structural layer to the electrical insulation layer. This allows a solid layered construction of the housing part to be achieved, which offers advantageous housing rigidity compared to conventional battery housings.

[0028] According to an advantageous embodiment of the housing part, at least one continuous gas passage region can be arranged in the structural layer and the electrical insulation layer to conduct fluids, in particular gases, from a housing interior into channels of the intermediate layer. Gases or particles generated in the event of a thermal event can be conducted via the gas passage region into the channels of the intermediate layer and thus removed from the housing interior.

[0029] According to a further aspect of the invention, a battery housing is proposed for a traction battery of an electrically operated vehicle, comprising a first housing part, in particular a housing cover, and a second housing part, wherein the first housing part has a structure made of several layers with different materials, at least comprising an outer layer made of a plastic, a metal layer with a steel insert, and a structural layer made of a structural material, wherein the outer layer and the metal layer are connected over a large area. The structural layer covers at least part of a surface of the outer layer and / or the metal layer. An intermediate layer is arranged between the structural layer and the combination of outer layer and metal layer.

[0030] In the battery housing designed with at least one first housing part as described above, some of the screw connections of a conventional battery housing can be eliminated due to the increased rigidity provided by the multi-layer construction with different materials. This reduces manufacturing and testing costs for the battery housing.

[0031] Furthermore, disruptive vibration behavior of large-surface components such as the housing cover or housing tray can be improved. Furthermore, easier disassembly in the event of a necessary repair is possible due to a reduced number of screws or fasteners.

[0032] The battery housing advantageously features functional integration, with individual layers performing different functions such as increasing strength, dampening vibration behavior, and creating gas channels. This creates more space for battery cells and thus achieves greater range.

[0033] According to a further aspect of the invention, a traction battery for an electrically operated vehicle is proposed, comprising a plurality of battery cells and such a battery housing, wherein the battery cells are arranged in a housing interior of the battery housing.

[0034] Advantageously, a traction battery with a battery housing such as the one described above allows for a larger internal volume for accommodating battery cells while maintaining the same external volume. This results in a greater energy content of the traction battery, which leads to a longer range for the vehicle equipped with it.

[0035] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0036] Showing:

[0037] Fig. 1 shows a cross section through part of a housing part, in particular a housing cover, for a battery housing of a traction battery of an electrically operated vehicle according to an embodiment of the invention;

[0038] Fig. 2 is an isometric view of a section of the housing part according to Figure 1 with an exposed intermediate layer according to an embodiment of the invention; and

[0039] Fig. 3 is an isometric view of a section of the housing part according to Figure 1 with exposed intermediate layer according to a further embodiment of the invention.

[0040] In the figures, identical or similar components are designated by identical reference numerals. The figures merely show examples and are not to be understood as limiting. Figure 1 shows a cross section through part of a housing part 10, in particular housing cover 10, for a battery housing 100 of a traction battery 200 of an electrically operated vehicle according to an exemplary embodiment of the invention.

[0041] The housing cover 10 is shown partially cut away in cross-section to provide an enlarged view of the structure. A second housing part 12 of the battery housing 100, which is connected to the housing cover 10, is shown only schematically as a plate. At least one battery module 52 is shown in the housing interior 40, which further comprises battery cells 50 of the traction battery 200 (not shown).

[0042] The housing cover 10 has a structure consisting of several layers 20, 22, 24, 26 made of different materials and includes an outer layer 20 made of a plastic, a metal layer 22 made of steel, and a structural layer 26 made of a structural material. The outer layer 20 and the metal layer 22 are bonded over a large area.

[0043] In the embodiment shown in Figure 1, the metal layer 22 rests on the outer layer 20 and is firmly connected to it. Alternatively, the metal layer 22 can be integrated into the outer layer 20. In particular, the metal layer 22 can be overmolded with the material of the outer layer 20 or cast into the material of the outer layer 20 to form a solid bond. This enables a firm connection or integration of the metal layer 22 into the outer layer 20, which can be manufactured inexpensively using common plastic manufacturing processes.

[0044] The structural layer 26 covers at least a part of a surface of the outer layer 20 and / or metal layer 22. An intermediate layer 24 is arranged between the structural layer 26 and the combination of outer layer 20 and metal layer 22.

[0045] The structural layer 26 is preferably formed from a material with a higher modulus of elasticity than the modulus of elasticity of the combination of outer layer 20 and metal layer 22. In particular, the structural layer 26 can comprise at least steel and / or aluminum and / or fiber-reinforced plastic, or can be formed from steel and / or aluminum and / or fiber-reinforced plastic. Bending forces or torsional forces can thus advantageously be conducted through the upper layer or lower layer of the multi-layer structure of the housing part 10. The intermediate layer 24 can preferably comprise a molded foam. In particular, the intermediate layer 24 can comprise plastic foam, for example polyurethane foam. Alternatively or additionally, it is also possible for the intermediate layer 24 to have folding cores made of paper, and / or glass fabric, and / or textiles.

[0046] The molded foam can advantageously be made of a material that distributes the force evenly when loaded in the Z direction and reduces the point load on a cell module 52 arranged inside the battery housing 100. The intermediate layer 24 can be manufactured, for example, by foaming or gluing it to the outer layer with a steel insert.

[0047] The housing part 10 comprises, on the side of the structural layer 26 facing the housing interior 40, an electrical insulation layer 28 made of an electrically insulating material. In particular, the electrical insulation layer 28 can be formed, for example, from plastic, ceramic, or a fiber-plastic composite material. The structural layer 26 is firmly connected to the electrical insulation layer 28. The insulation layer 28 can advantageously be applied as the innermost layer of the battery housing 100 and, for safety reasons, used as an electrical insulator for a cell module 52 mounted above it.

[0048] As further shown in Figure 1, the intermediate layer 24 can have channels 30 for discharging fluids, particularly gases. Fluids, particularly gases, generated during a thermal event, for example, can be discharged via the channels 30.

[0049] Furthermore, a continuous gas passage region 32 is arranged in the structural layer 26 and the electrical insulation layer 28 in order to conduct the fluids, in particular gases, from the housing interior 40 into the channels 30 of the intermediate layer 24. In the battery module 52, an opening region 54 of the battery cells 50 is schematically shown, from which fluids, in particular gases, can flow into the channels 30 via the gas passage region 32.

[0050] The combination of multiple layers 20, 22, 24, 26 made of different materials enables improved inherent rigidity of the housing cover 10. Such a multi-layer structure eliminates the need for attachment points for the housing cover 10 and ensures even load distribution when forces are applied at specific points. For example, forces in a vertical Z-direction of the component 10 are distributed over a large area during proper installation in a vehicle, so that only a reduced surface load acts on the interior of the battery 200. The integration of multiple requirements into the individual layers 20, 22, 24, 26, such as the formation of gas channels 30 and the presence of insulating properties, is advantageously possible.

[0051] Figure 2 shows an isometric view of a section of the housing part 10 according to Figure 1 with exposed intermediate layer 24 according to an embodiment of the invention.

[0052] The housing part 10 is shown cut away, so that in a part of the housing part 10 only the intermediate layer 24 can be seen. The intermediate layer 24 is made of molded foam and is shown in a design for prismatic battery cells. This can be seen from the elliptical venting openings 34 arranged in a row, which are located in the central region of the intermediate layer 24. Fluids, in particular gases from venting openings of the battery cells, can escape through the venting openings 34 of the intermediate layer 24. In the intermediate layer 24, the fluids can then be discharged from the venting openings 34 via the channels 30. For reasons of clarity, only individual venting openings 34 and channels 30 are provided with reference symbols.

[0053] Figure 3 shows an isometric view of a section of the housing part according to Figure 1 with an exposed intermediate layer according to a further embodiment of the invention.

[0054] This design of the intermediate layer 24 is intended for round cells. The vents 34 in the intermediate layer 24 are circular and arranged in a densely packed configuration for cylindrical round cells, which are arranged side by side. The channels 30 for draining the fluids connect the various vents 34. List of Reference Symbols

[0055] 10 Housing part

[0056] 12 second housing part

[0057] 20 Outer layer

[0058] 22 metal layer

[0059] 24 Connection layer

[0060] 26 structural layer

[0061] 28 electrical insulation layer

[0062] 30 channels

[0063] 32 Gas passage area

[0064] 34 Degassing opening

[0065] 40 Housing interior

[0066] 50 battery cells

[0067] 52 Battery module

[0068] 54 Opening area

[0069] 100 battery cases

[0070] 200 traction battery

Claims

Patent claims 1. Housing part (10), in particular housing cover (10), for a battery housing (100) of a traction battery (200) of an electrically powered vehicle, for connecting to a second housing part (12) of the battery housing (100), with a structure of several layers (20, 22, 24, 26) with different materials, comprising at least - an outer layer (20) made of a plastic, - a metal layer (22), in particular made of steel, - a structural layer (26) made of a structural material, wherein the outer layer (20) and the metal layer (22) are connected over a large area, wherein the structural layer (26) covers at least a part of an area of ​​the outer layer (20) and / or the metal layer (22), wherein an intermediate layer (24) is arranged between the structural layer (26) and the combination of outer layer (20) and metal layer (22).

2. Housing part according to claim 1, wherein the Meta II layer (22) is integrated into the outer layer (20), in particular wherein the metal layer (22) is overmolded with the material of the outer layer (20) or is cast into the material of the outer layer (20).

3. Housing part according to claim 1 or 2, wherein the structural layer (26) is made of a Material with a higher modulus of elasticity than the modulus of elasticity of a combination of outer layer (20) and metal layer (22), in particular wherein the structural layer (26) comprises at least steel and / or aluminium and / or fiber-reinforced plastic, in particular is made of steel and / or aluminium and / or fiber-reinforced plastic.

4. Housing part according to one of the preceding claims, wherein the Intermediate layer (24) comprises a molded foam, in particular wherein the Intermediate layer (24) comprising at least one of plastic foam, in particular polyurethane foam, folding cores made of paper, glass fabric, textiles.

5. Housing part according to claim 4, wherein the intermediate layer (24) has channels (30) for draining fluids, in particular gases.

6. Housing part according to one of the preceding claims, further comprising an electrical insulating layer (28) made of an electrically insulating material, in particular of at least one of plastic, ceramic, fiber-reinforced plastic composite material.

7. Housing part according to claim 6, wherein the Meta II layer (22) is firmly connected to the intermediate layer (24) and / or the structural layer (26) is firmly connected to the electrical insulating layer (28).

8. Housing part according to one of claims 5 to 7, wherein at least one continuously formed gas passage area (32) is arranged in the structural layer (26) and the electrical insulation layer (28) to guide fluids, in particular gases, from a housing interior (40) into channels (30) of the intermediate layer (24).

9. Battery housing (100) for a traction battery (200) of an electrically powered vehicle, comprising a first housing part (10), in particular a housing cover (10), according to one of the preceding claims, and a second housing part (12), wherein the first housing part (10) has a structure of several layers (20, 22, 26) with different materials, comprising at least - an outer layer (20) made of a plastic, - a metal layer (22) with a steel insert, - a structural layer (26) made of a structural material, wherein the outer layer (20) and the metal layer (22) are connected over a large area, wherein the structural layer (26) covers at least a part of an area of ​​the outer layer (20) and / or the metal layer (22), wherein an intermediate layer (24) is arranged between the structural layer (26) and the combination of outer layer (20) and metal layer (22).

10. Traction battery (200) for an electrically powered vehicle, comprising a plurality of battery cells (50) and a battery housing (100) according to claim 9, wherein the battery cells (50) are arranged in a housing interior (40) of the battery housing (100).

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