Frame for protecting battery box of vehicle

Abstract

The present disclosure relates to a frame (10) for protecting a battery case (20) of a vehicle, where the frame (10) is fixed to the battery case (20). The frame (10) includes a first longitudinal outer member (11) directly attached to an underside of a first rocker (31) of the vehicle and a second longitudinal outer member (14) directly attached to an underside of a second rocker (32) of the vehicle. The frame (10) further comprises a plurality of cross members (12) below the battery case (20), the plurality of cross members (12) joining the first longitudinal outer member (11) to the second longitudinal outer member (14). The present disclosure further relates to a vehicle comprising such a frame.

Description

[0001] This application claims the benefit of EP22383156.1 filed on November 30, 2022.

[0002] The present disclosure relates to a frame for protecting a battery compartment of a vehicle and a vehicle including such a frame. Background Art

[0003] Traction batteries are an important part of electric and hybrid vehicles, powering the vehicle's electric motors. The electronic and chemical properties of these batteries make them particularly sensitive to high mechanical loads, such as crash shock.

[0004] One of the challenges in the automotive industry is protecting the traction battery in the event of a crash, in order to ensure passenger safety and avoid failures.

[0005] Vehicles such as cars contain a structural framework that is designed to withstand and absorb impacts, such as in the event of a collision with another car, an obstacle, or a pedestrian. In this sense, the structural framework of a car may include, for example, bumpers, pillars (A-pillars, B-pillars, C-pillars, D-pillars), side impact beams, rocker sills or door sills, hinge pillars, and shock absorbers.

[0006] In a vehicle, the traction battery is typically placed inside a battery box, which is typically mounted in the lower area of ​​the vehicle below the passenger compartment. In the event of a crash, the vehicle's structural frame absorbs most of the impact energy, but some energy may still be transferred to the battery box.

[0007] In order to extend battery life and protect it from external impact, the automotive industry has invested a lot of effort to provide battery housings and load-bearing structures suitable for electric vehicles. As a result, over the past few years, a variety of protective elements have been designed and manufactured to house and protect traction batteries.

[0008] Battery boxes can be made of materials with high stiffness, high strength and low weight. To improve the protection of the battery in the event of an impact, steel battery boxes or battery trays and battery boxes made of polymer (plastic) or composite components have been designed. However, the battery box of an electric vehicle may not always be configured to handle the energy involved in a car collision. Problems have been found with inward intrusion in the event of a side impact.

[0009] One way to protect the battery in a crash could be to modify the structural properties of the vehicle's body-in-white (BIW) so that more energy can be absorbed and less impact energy reaches the battery compartment. For example, the door sills could be reinforced. However, due to space constraints, modifying the vehicle's body-in-white (BIW) may not always be an option and could negatively impact the vehicle's overall design.

[0010] US2022 / 0134857 A1 discloses a frame-mounted battery housing. This document discloses a vehicle comprising a vehicle frame having first and second frame rails. The disclosed battery housing includes first and second side members that are connected and deformable relative to the first and second frame rails of the vehicle. The frame rails are attached to the inner side of the rocker rails.

[0011] Protecting the integrity of the battery box without significantly increasing the overall weight of the vehicle or changing its design is a challenge. There is also the further challenge of safeguarding the integrity of the battery box within the given space constraints. Summary of the Invention

[0012] In a first aspect, a frame for protecting a battery compartment of a vehicle is provided. The frame can be secured to the battery compartment. The frame includes a first longitudinal outer member directly attached to the underside of a first rocker of the vehicle and a second longitudinal outer member directly attached to the underside of a second rocker of the vehicle. The frame includes a plurality of transverse members below the battery compartment for connecting the first longitudinal outer member to the second longitudinal outer member.

[0013] Because the rocker primarily transfers energy to the frame, to which it is directly attached, the load on the battery compartment is significantly reduced. The frame absorbs and transmits the energy generated during an impact, thereby protecting the integrity of the battery compartment. This provides a simple and efficient way to protect the battery compartment without the need for additional components.

[0014] Additionally, multiple cross members can transfer energy to the other side of the vehicle during a vehicle impact, thereby distributing the energy and reducing damage to the battery compartment. By attaching the outer members directly to the underside of the rocker rails, the space between the rocker rails is unoccupied. As a result, the space between the rocker rails can be occupied by the battery compartment. This allows the size of the battery compartment to be increased, which allows for the accommodation of increased-sized battery cells or the placement of systems or reinforcement structures within the battery compartment.

[0015] Throughout this disclosure, a battery case may be considered herein as a housing for a battery, wherein the battery may be composed of a plurality of battery cells. The battery case may include a battery tray and a cover, wherein the battery tray is made of, for example, steel or a polymer-reinforced composite material.

[0016] The underside of the rocker may be considered the bottom or lower side or surface of the rocker.

[0017] In some examples, the plurality of cross-members connecting the first longitudinal outer member to the second longitudinal outer member can be tubular or at least partially tubular. In some examples, the tubes can be made of steel. Steel tubes can provide the cross-members with resistance to high loads and efficiently distribute energy.

[0018] In other examples, the plurality of cross members connecting the first longitudinal outer member to the second longitudinal outer member may be stamped beams.Stamping, particularly hot stamping, is a well-known technique for providing components with high strength and suitable shape.

[0019] In some examples, the plurality of transverse members may include at least one transverse member that is curved in the lateral direction. On the one hand, the curvature can predefine the kinematics of the deformation in the event of an impact. On the other hand, it can help transform a lateral impact accompanied by lateral deformation into a deformation extending in the longitudinal direction, thereby reducing the energy and impact that needs to be absorbed in the lateral direction.

[0020] In some examples, two or more cross members may have the same size and shape. In some examples, all cross members may have the same size and shape. This can facilitate the manufacture and assembly of the battery protection frame.

[0021] In some examples, one or more cross members include a first end portion for connecting to a first longitudinal outer member, a second end portion for connecting to a second longitudinal outer member, and a curved intermediate portion. Compared to straight cross members, the curved cross members can have increased buckling strength, thereby better absorbing side impacts or better controlling deformation during impacts.

[0022] In some examples, the first end portion and the second end portion are positioned at substantially the same longitudinal position, wherein the curved intermediate portion is positioned further rearward or further forward than the first end portion and the second end portion. In the event of a side impact, lateral deformation of the outer member and the cross member can be at least partially converted into longitudinal deformation.

[0023] In some examples, two adjacent cross-members from the plurality of cross-members are joined at their curved mid-portions. The curved cross-members enable energy transfer from one end portion to the other. Furthermore, energy absorbed in a collision can be transferred between adjacent curved cross-members in the longitudinal direction of the vehicle. The load of a side impact can be transmitted along the length of the vehicle.

[0024] In some examples, multiple cross members can be joined to the first and second longitudinal outer members via brackets. The brackets can be considered structural elements. They can be configured to receive the cross members at the inner sides of the brackets. One or more brackets can be configured to receive more than one cross member.

[0025] In some examples, the first and second longitudinal outer members and the cross member are joined to the bracket by welding.

[0026] Throughout this disclosure, longitudinal, vertical, and lateral directions are defined to provide spatially oriented components of (the structural framework of) a vehicle. These directions are generally perpendicular to one another. Thus, a longitudinal outer member has a length in the longitudinal direction (the longitudinal direction is generally parallel to the direction of travel of the vehicle on which the component is mounted), a height in the vertical direction, and a width in the lateral direction. For example, a rocker may generally extend in the longitudinal direction, and a cross member may generally extend in the lateral direction between the longitudinal outer members. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Non-limiting examples of the present disclosure will now be described with reference to the accompanying drawings, in which:

[0028] Figure 1A A top view illustrating an example of a frame for protecting a battery compartment of a vehicle;

[0029] Figure 1B Shown include Figure 1A a bottom view of the vehicle showing a frame for protecting the battery box;

[0030] Figure 1C shows a front view of another example of a frame for protecting a battery box of a vehicle;

[0031] Figure 1D Shown Figure 1A a top view of a lateral end portion of the frame in FIG;

[0032] Figure 2 A top perspective view showing yet another example of a frame for protecting a battery box of a vehicle;

[0033] Figure 3 A top perspective view illustrating yet another example of a frame for protecting a battery compartment of a vehicle;

[0034] Figure 4 shows a bottom view of another example of a frame for protecting a battery compartment of a vehicle;

[0035] Figure 5A A top perspective view showing yet another example of a frame for protecting a battery box of a vehicle;

[0036] Figure 5B Shown Figure 5A a top view of a lateral end portion of the frame in FIG;

[0037] Figure 6 A front view showing an example of a portion of a frame for protecting a battery box of a vehicle, the frame being secured to the battery box and attached directly to a rocker of the vehicle;

[0038] Figure 7shows a top perspective view of an example of a frame for protecting a battery box of a vehicle, the frame being secured to the battery box and attached directly to a rocker of the vehicle;

[0039] The drawings refer to example embodiments and are merely intended to aid understanding of the claimed subject matter and are not intended to limit the same in any way. DETAILED DESCRIPTION

[0040] In the drawings, the same reference numerals are used in different drawings to indicate matching elements.

[0041] Figures 1A to 1D The frame 10 for protecting the battery box 20 of a vehicle according to an example of the present disclosure is schematically shown. Figures 1A to 1D In the example, the vehicle may be an electric truck.

[0042] The frame is fixed to the battery box 20 (not shown in this figure). The frame 10 includes a first longitudinal outer member 11, a second longitudinal outer member 14, and a plurality of cross members 12 below the battery box 20, which connect the first longitudinal outer member 11 to the second longitudinal outer member 14. The first longitudinal outer member 11 and the second longitudinal outer member 14 of the frame 10 are directly attached to the underside of the first rocker 31 and the second rocker 32 of the vehicle, respectively (not shown).

[0043] In the event of a side impact, one of the first longitudinal outer member 11 and the second longitudinal outer member 14 may absorb energy and transfer it to the other longitudinal outer member of the frame, thereby reducing the impact energy received by the battery box 20 .

[0044] like Figure 1A As shown schematically, the plurality of cross-members may include at least one curved cross-member, i.e., the cross-member may be curved in a lateral direction. One or more cross-members may include: a first end portion 17 for connecting to the first longitudinal outer member 11; a second end portion 18 for connecting to the second longitudinal outer member 14; and a curved middle portion 19, wherein the first end portion 17 and the second end portion 18 may be positioned at approximately the same longitudinal position, and wherein the curved middle portion 19 may be positioned further rearward or further forward of the first end portion 17 and the second end portion 18.

[0045] Connecting the longitudinal outer members 11, 14 with the curved cross member 12 can result in higher energy transfer between one longitudinal outer member and the other, thereby resulting in improved force distribution and a reduction in the energy received by the battery compartment 20. Compared to straight cross members, the curved cross member can have increased buckling strength. After a crash event, the structural integrity of the battery compartment 20 can be maintained.

[0046] like Figure 1A As shown, two adjacent cross-members from the plurality of cross-members may be joined to each other at their curved mid-portions 19, for example, by welding. In some examples, a cross-member may be joined to only a single other adjacent cross-member. An interior space may be defined between adjacent curved cross-members that are not joined to each other. In some examples, the interior space may define a generally diamond-shaped space.

[0047] When the cross members are joined together, the energy and load generated during an impact are distributed not only from the cross members 12 to the longitudinal outer members 11, 14, but also between adjacent curved cross members 12 in the longitudinal direction of the vehicle. The connection between adjacent curved cross members 12 improves load transfer and further reduces the negative impact that an impact may have on the battery compartment 20. In particular, because the load is more effectively transferred and displaced elsewhere, inward intrusion of the rocker and / or battery compartment can be reduced or avoided.

[0048] In some examples, the two or more cross members 12 connecting the first longitudinal outer member 11 to the second longitudinal outer member 14 of the frame 10 can have the same size and shape. The same cross members 12 can simplify the structure of the frame and thus simplify the manufacturing process and assembly of the battery protection frame. In some examples, such as Figure 1A As shown, all cross members are identical in shape.

[0049] exist Figure 1A In the example of , eight cross members may be used. In other examples, the number of cross members may vary, for example, depending on the length of the vehicle's rocker or the length of the vehicle's battery box.

[0050] In some examples, the first longitudinal outer member 11 and the second longitudinal outer member 14 can be roll-formed. In other examples, the longitudinal outer members can be formed using hot stamping or cold stamping. In some examples, two parts can be formed, for example, by hot stamping or cold stamping, and then attached to each other to form a closed cross-section.

[0051] In some examples, longitudinal outer members 11 and 14 may be made of steel. In some examples, martensitic steel may be used. In some examples, longitudinal outer members 11 and 14 may be made of ultra-high-strength steel. The use of ultra-high-strength steel can provide longitudinal outer members 11 and 14 that are lightweight, strong, and durable. This can achieve protection for battery compartment 20 without significantly increasing the weight of the vehicle.

[0052] Ultra-high-strength steel may be considered herein as steel having an ultimate tensile strength of at least 1000 MPa, and optionally at least 1500 MPa. Ultra-high strength can be achieved by applying suitable heat treatment to achieve this ultimate tensile strength. In particular, the ultimate tensile strength can be achieved by applying suitable heat treatment to achieve a martensitic microstructure. Boron steels such as 22MnB5 or 37MnB5 are two examples of suitable steels. In other examples, martensitic cold-forming steels such as MS1200 may be used.

[0053] In some examples, the plurality of cross members 12 may be hydroformed. In some examples, the plurality of cross members 12 may be tubes. The tubes may be made of steel. In further examples, the plurality of cross members 12 may be made of ultra-high strength steel.

[0054] like Figure 1A As shown, a plurality of cross members 12 can be joined to the first longitudinal outer member 11 and the second longitudinal outer member 14. In particular, the cross members 12 can be joined at corresponding flanges of the longitudinal outer members. Figure 1A In the embodiment, the transverse members can be attached to the longitudinal outer members with brackets 13.

[0055] The bracket can be configured to receive the cross member at the inner side of the bracket. In some examples, the bracket 13 can join the end portions 17, 18 of the cross member 12 to the longitudinal outer members 11, 14. This is also Figure 1D As can be seen in the figure, the Figure 1A lateral end portions of the frame.

[0056] At the front and rear ends of the frame 10, a single cross member is connected to the longitudinal outer members. In various examples, a single bracket 13 can join the end portions of two adjacent cross members 12 to the longitudinal outer members 11, 14. The bracket 13 can receive the end portions of adjacent cross members 12. The end portions of adjacent cross members can be welded to each other and to the bracket 13. Thus, a side impact affecting the bracket will affect multiple cross members.

[0057] One cross member (e.g., a curved tube) can be attached to an adjacent cross member at the longitudinal outer member, and the same cross member can be attached to another adjacent cross member at the central area below the battery compartment. So the cross member is connected to the adjacent cross members on both sides.

[0058] In some examples, bracket 13 can be a structural element made of steel. Bracket 13 can have any shape suitable for connecting longitudinal outer members 11, 14 to cross member 12. In some examples, bracket 13 can be generally rectangular. Bracket 13 can be wide enough to ensure secure engagement of cross member 12 to longitudinal outer members 11, 14.

[0059] In some examples, the first and second longitudinal outer members 11 and 14 and the cross member 12 may be joined to the bracket 13 by welding.

[0060] Figure 1B Schematically shows the Figure 1A The frame 10 of the vehicle is fixed to the battery box 20. The frame 10 includes a plurality of cross members 12 below the battery box 20, and the plurality of cross members 12 connect the first longitudinal outer member 11 to the second longitudinal outer member 14. The first longitudinal outer member 11 of the frame 10 is directly attached to the underside of the first rocker of the vehicle, and the second longitudinal outer member 14 of the frame 10 is directly attached to the underside of the second rocker of the vehicle.

[0061] As in Figure 1B As can be seen in FIG, the longitudinal outer members 11, 14 of the frame 10 can extend between the front and rear wheels of the vehicle. In some examples, the length of the longitudinal outer members 11, 14 can correspond at least to the length of the battery box 20. In some examples, the length and width of the longitudinal outer members 11, 14 can be similar to the length and width of the vehicle's rocker 31, 32. In some examples, the length of the longitudinal outer members 11, 14 can extend the entire length of the battery box, or extend at least 70% of the length of the battery box. In various examples, the length of the longitudinal outer members 11, 14 can be between 70% and 90% of the length of the rocker. In some examples, the longitudinal outer members 11, 14 can have a width of, for example, 80 mm. The width of the longitudinal outer members can be, for example, 50% to 100% of the width of the rocker to which they are attached.

[0062] Figure 1C A cross section of another example of a frame 10 for protecting a battery compartment 20 of a vehicle is shown. In this example, the first longitudinal outer member 11 and the second longitudinal outer member 14 of the frame 10 can have a generally figure-eight-shaped cross-section, i.e., two cavities or hollow cells separated by an intermediate wall. Longitudinal outer members having such a figure-eight-shaped cross-section can improve energy absorption at the beginning of a collision event while also reducing the weight of the frame 10. The figure-eight-shaped cross-section can be formed by, for example, roll forming. The figure-eight-shaped cross-section can also be formed by joining two hot stamped and / or cold stamped parts to each other.

[0063] In other examples, the first longitudinal outer member 11 and the second longitudinal outer member 14 may be completely hollow. Figure 1C It is not shown in the figure, but the frame is fixed to the battery box, and the first longitudinal outer member 11 and the second longitudinal outer member 14 are directly attached to the lower side of the rocker of the vehicle.

[0064] In a further example, for example Figure 2 and Figure 3As shown, the frame 10 may include one or more straight cross members 16 for connecting the first longitudinal outer member 11 to the second longitudinal outer member 14 .

[0065] Figure 2 An example of a frame 10 is shown which includes a straight cross member 16 at the front end of the frame and a straight cross member at the rear end of the frame. Figure 1A 、 Figure 1B and Figure 1D The bent cross members can be bent in a similar manner as shown in the example of Figure 1A A similar approach is described for attachment to adjacent curved cross members.

[0066] The straight cross member at the front end and / or the straight cross member at the rear end can be joined to the corresponding adjacent curved cross member by, for example, welding. The first and second ends of the straight cross member 16 can be joined to the first and second longitudinal outer members with brackets 13. The cross member 12 in this example can be a tubular cross member, as shown in FIG. Figure 1A shown.

[0067] In some other examples, such as Figure 3 As shown, straight cross members 16 may be located between adjacent curved cross members 12. In some examples, straight cross members 16 may be located between curved cross members that are not joined to one another.

[0068] exist Figure 3 In the example shown, a single bracket 13 can join three cross members 12 to the longitudinal outer members. More specifically, in this example, a single bracket is used to join one straight cross member and two curved cross members to the longitudinal outer members 11, 14. At the opposite end, a similar arrangement of brackets can be found that receive multiple cross members.

[0069] A plurality of cross members may be welded to each other and to the bracket. A wider area below the battery box and between the longitudinal outer members 11, 14 may be covered by the cross member 12, thereby enabling better energy distribution and potentially reducing battery damage.

[0070] In some examples, such as Figure 1A 、 Figure 1B and Figure 3 In some examples, the frame 10 may include at least eight curved cross members 12 . In other examples, the frame 10 may include at least eight curved cross members 12 and at least three straight cross members 16 .

[0071] In a further example, Figure 4As shown, the plurality of cross members 12 of the frame 10 may be roll-formed tubes that may be joined to the first and second longitudinal outer members 11, 14 using brackets.

[0072] In this example, as in Figure 4 As can be seen in FIG, two adjacent curved cross members 12 of the plurality of curved cross members of the frame 10 can be joined to each other along their curved middle portions 19 by means of brackets 13, rather than by means of brackets 13 as shown in FIG. Figures 1A to 3 The cross members are welded to each other as shown in the example.

[0073] Further, the frame 10 may include two straight rolled formed tubes at the front and rear ends of the frame. Figure 4 As shown, each straight roll-formed tube may be joined to the middle portion of an adjacent curved roll-formed tube by a bracket.

[0074] Figure 5A and Figure 5B Another example of a frame 10 for protecting a battery box 20 of a vehicle is shown. In this example, the plurality of transverse members 12 connecting the first longitudinal outer member 11 to the second longitudinal outer member 14 may be beams. The beams may be made of steel, such as ultra-high strength steel.

[0075] The cross member in the example of the fifth figure can be formed by stamping. The cross section of the stamped cross member can be generally hat-shaped. The cross section can include a bottom wall and first and second side walls. The cross section can further include flanges extending outwardly from the first and second side walls.

[0076] The cross member in this example may have an open cross section. In some examples, a cover plate may be provided to provide a cross member with a closed cross section and a corresponding increase in torsional strength and stiffness.

[0077] The stamped cross member may be joined to the longitudinal outer members using brackets in a similar manner as previously shown. However, the stamped cross member may also be formed in such a way that it includes one or more flanges for attachment to the longitudinal outer members.

[0078] In some examples, the beam can be a hot stamped beam. In other examples, the beam can be a cold stamped beam. Hot stamping can involve heating the blank to a suitable temperature, particularly above the austenitizing temperature, more particularly above the Ac3 temperature. After suitable austenitization, the blank can be positioned in a press, deformed in the press to give it its final shape, and rapidly cooled (quenched, particularly at a rate above the critical cooling rate of the steel used) in the press to obtain a martensitic microstructure.

[0079] Ultra high strength steel (UHSS), such as boron steel, may be used to obtain an ultimate tensile strength of 1000 MPa or more, in particular 1500 MPa or more.Using ultra high strength steel may provide a cross member that is lightweight while being stiff and strong.

[0080] In the example of FIG5A, the cross member includes six curved stamped beams, each including a first end portion connected to a first longitudinal outer member, a second end portion connected to a second longitudinal outer member, and a curved middle portion. Adjacent cross members can be joined to each other at their curved middle portions, for example, by welding. Figure 5A The frame 10 further includes two straight stamped beams at or near the front and rear ends of the frame, which may be joined to the middle portions of adjacent curved stamped beams, such as by welding.

[0081] Furthermore, the stamped beam may comprise a hat-shaped cross section. Figure 5B As shown, the end portions 17, 18 of the stamped beams can be shaped so that the cross members can be directly joined to the longitudinal outer members without any additional components (e.g., without brackets). The end portions 17, 18 of the stamped beams can be directly joined to the longitudinal outer members by welding (e.g., spot welding). This can provide a simpler frame with fewer parts and faster assembly.

[0082] Figure 6 Another example of a frame 10 for protecting a battery compartment 20 of a vehicle is schematically shown. The frame 10 is secured to the battery compartment 20, with a first longitudinal member of the frame directly attached to the underside of a first rocker 31. A second longitudinal outer member 14 of the frame 10 is directly attached to the underside of a second rocker 32 of the vehicle (not shown). Figure 6 The first longitudinal outer member 11 is shown attached with screws directly to the underside of the first rocker 31. In some examples, the first and second longitudinal outer members may be attached directly to the underside of the rocker by welding or using other fasteners.

[0083] In a side impact, the rockers 31, 32 receive energy that could potentially damage the battery compartment 20. Surprisingly, it has been discovered that by attaching the longitudinal outer members 11, 14 of the frame 10 directly to the underside of the rockers 31, 32, the energy generated by a side impact can be effectively absorbed and distributed throughout the frame 10, and a significant reduction in the energy received by the battery compartment can be achieved. Furthermore, the space between the rockers 31, 32 is unoccupied, and thus, such space can be occupied by the battery compartment 20. As a result, the size of the battery compartment 20 can be increased.

[0084] like Figure 6As shown, the frame 10 can be secured to the battery box 20 with at least one or more bolts. In this example, the battery box can be secured to a bracket of the frame 10. The bracket can include suitable bolt holes or other fastener holes.

[0085] Figure 7 Visible in Figure 6 A top perspective view of the frame 10 disclosed in FIG. Figure 7 The frame 10 is shown secured to a rectangular battery box 20 and to a first rocker 31 and a second rocker 32 of the vehicle. The longitudinal outer members 11, 14 of the frame 10 are attached directly to the undersides of the rockers 31, 32 of the vehicle. In some examples, once the frame 10 is secured to the battery box 20, the longitudinal outer members 11, 14 of the frame 10 can be attached directly to the undersides of the rockers 31, 32.

[0086] In the event of a side impact, the longitudinal outer members 11 and 14 of the frame 10 can receive energy and load from the rocker rails 31 and 32, absorb the energy, and transmit it to the other side of the frame 10 through the cross members 12 and 16. The frame 10 can absorb and redistribute the impact energy, and the integrity of the battery box 20 can be protected.

[0087] Although only a few examples are disclosed herein, other substitutions, modifications, uses, and / or equivalents of these examples are possible. Furthermore, all possible combinations of the examples are contemplated. Thus, the scope of this disclosure should not be limited by the specific examples, but should be determined solely by a reasonable reading of the following claims.

Claims

1. A frame (10) for protecting a battery box (20) of a vehicle, wherein: The longitudinal direction is defined as a direction parallel to the driving direction of the vehicle, the lateral direction is defined as a horizontal direction perpendicular to the driving direction, and the vertical direction is defined as a direction perpendicular to the longitudinal direction and the lateral direction, and wherein, The frame (10) is configured to be fixed to the battery box (20), and The framework (10) comprises: a first longitudinal outer member (11) extending substantially in the longitudinal direction and configured to be directly attached to a lower side of a first rocker (31) of the vehicle, a second longitudinal outer member (14) extending generally in the longitudinal direction and configured to be attached directly to an underside of a second rocker (32) of the vehicle; and a plurality of transverse members (12, 16) arranged below the battery box to extend in the lateral direction, the plurality of transverse members (12, 16) connecting the first longitudinal outer member (11) to the second longitudinal outer member (14), The plurality of transverse members (12, 16) include one or more transverse members (12) bent forward or backward along the lateral direction.

2. The frame according to claim 1, wherein Two or more of the cross members (12, 16) are of the same size and shape, and optionally wherein all of the cross members are of the same size and shape.

3. The frame according to claim 1 or 2, wherein: At least two cross members (12, 16) are joined to one another, in particular by welding or by means of a bracket (13).

4. The frame according to any one of claims 1 to 3, wherein One or more of the cross members (12) include: a first end portion (17) for connecting to the first longitudinal outer member (11); a second end portion (18) for connecting to the second longitudinal outer member (14); and a curved middle portion (19), wherein the first end portion (17) and the second end portion (18) are positioned at approximately the same longitudinal position, and wherein the curved middle portion (19) is positioned further rearward or further forward than the first end portion (17) and the second end portion (18).

5. The frame according to claim 4, wherein Two adjacent cross members among the plurality of cross members (12) are joined to each other at curved middle portions (19) thereof.

6. The frame according to any one of claims 1 to 5, wherein The plurality of transverse members (12, 16) are joined to the first longitudinal outer member (11) and the second longitudinal outer member (14) via brackets (13).

7. The frame according to claim 6, wherein A single bracket (13) joins at least two transverse members (12) to longitudinal outer members (11, 14).

8. A frame according to claims 6 and 7, wherein The first longitudinal outer member (11), the second longitudinal outer member (14) and the transverse member (12) are joined to the bracket (13) by welding.

9. The frame according to any one of claims 1 to 8, wherein The plurality of cross members (12) are tubes.

10. The frame according to any one of claims 1 to 8, wherein The plurality of transverse members (12) are beams.

11. The frame according to any one of claims 1 to 10, wherein The first longitudinal outer member (11) and the second longitudinal outer member (14) have a substantially hollow cross-section, and optionally have at least two hollow cells.

12. A frame according to any one of claims 1 to 11, wherein The first longitudinal outer member (11) and the second longitudinal outer member (14) are roll-formed.

13. A frame according to any one of claims 1 to 12, wherein The first longitudinal outer member (11) and the second longitudinal outer member (14) are made of ultra-high strength steel.

14. A frame according to any one of claims 1 to 13, wherein The frame (10) is fixed to the bottom of the battery box (20).

15. A vehicle comprising a frame according to any one of claims 1 to 14.

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