An integrated steel roller-pressed profile and battery shell

Abstract

The utility model discloses an integrated steel roller pressing section bar, which is obtained by cold bending a steel plate for multiple times and has a closed structure including three closed rectangular cavities, comprising a first cavity, a second cavity and a third cavity; the first cavity and the second cavity are formed by bending the two ends of the plate material, and a pair of top corners of the first cavity and the second cavity are fixedly connected through a first welding point; the third cavity is formed by bending the middle part of the plate material, and each of the first cavity and the third cavity and the second cavity and the third cavity has a shared edge beam; the outer edge surface of the roller pressing section bar is a plane, and the roller pressing section bar has sufficient rigidity, strength and bending resistance, and the structure design is reasonable and the material is saved. The utility model also discloses a battery shell using the integrated steel roller pressing section bar, which has the advantages of lightweight, high strength, high production efficiency, flexible design and the like.

Description

Technical Field

[0001] This utility model relates to the field of automotive profile technology, and in particular to an integrated steel roll-formed profile and battery casing. Background Technology

[0002] With the increasing global emphasis on environmental protection and sustainable development, new energy vehicles, as a green and low-carbon mode of transportation, are experiencing rapid development. In the development of new energy vehicles, battery technology, as a core component, has always been a key focus of research and innovation. The battery casing, as a crucial component protecting the battery's safety and stable operation, has also received considerable attention for its technological development. The battery casing of new energy vehicles is mainly used to protect the battery pack and needs to possess good safety, lightweight, reliability, and cost-effectiveness. Common battery casing materials include aluminum alloys, steel, and composite materials. Among them, aluminum alloys, due to their light weight and good machinability, have become the mainstream technology for power battery system casings. However, their processing cost is high, increasing the manufacturing cost of new energy vehicles. Their strength is relatively lower than that of steel materials, resulting in slightly inferior protective performance in extreme situations such as collisions. Composite materials, on the other hand, have shown certain advantages in weight reduction and electrical insulation, but their cost is relatively high, and large-scale application still faces certain challenges. Therefore, developing a lightweight, high-strength, high-production-efficiency, and low-cost battery casing and its profile has become an effective method to improve the performance and reduce the cost of new energy vehicles. Utility Model Content

[0003] To address the aforementioned problems in the existing technology, the purpose of this utility model is to provide an integrated steel roll-formed profile and battery casing.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: An integral steel roll-formed profile, wherein the roll-formed profile is a closed structure containing three closed rectangular cavities, formed by multiple cold bending of a steel plate, including a first cavity, a second cavity, and a third cavity; the first cavity and the second cavity are formed by bending the two ends of the plate, and a pair of apex corners of the first cavity and the second cavity are fixedly connected by a first weld point; the third cavity is formed by bending the middle of the plate, and the first cavity and the third cavity, as well as the second cavity and the third cavity, each have a cavity wall shared by the two cavities; the outer edge surface of the roll-formed profile is flat; the width of the third cavity is not less than the width of the first cavity.

[0005] A further improvement of the present utility model lies in that: the roll-formed profile comprises a first upper wall, a first left side wall, a first lower wall, a first right side wall, a second upper wall, a second left side wall, a second lower wall, a second right side wall, a third left side wall and a third lower wall; the first upper wall, the first left side wall, the first right side wall and the first lower wall enclose to form a first cavity, the second upper wall, the second left side wall, the second right side wall and the second lower wall enclose to form a second cavity; the first lower wall, the third left side wall, the third lower wall and the second left side wall enclose to form a third cavity.

[0006] A further improvement of the present utility model lies in that: the included angle between the first lower wall and the first right side wall, and the included angle between the second upper wall and the second left side wall are fixedly connected by a first welding spot.

[0007] A further improvement of the present utility model lies in that: when the width of the third cavity is the same as the width of the first cavity, the cross-section of the roll-formed profile is L-shaped; when the width of the third cavity is greater than the width of the first cavity, the cross-section of the roll-formed profile is in a "product-shaped" structure.

[0008] A further improvement of the present utility model lies in that: two ends of the plate are respectively welded and fixed to the cavity walls of the third cavity, and the welding method can be lap welding, hook edge welding, bent seam welding or vertical welding.

[0009] A further improvement of the present utility model lies in that: the third left side wall and the third lower wall are provided with an inwardly recessed hat-shaped reinforcing rib structure, and the hat-shaped reinforcing rib structure and the end of the plate form a mating surface.

[0010] A further improvement of the present utility model lies in that: the corners of the first cavity, the second cavity and the third cavity are all rounded corners.

[0011] A battery case comprises a frame structure formed by four side beams connected end to end, and a central connecting beam arranged inside the frame structure, wherein the side beams adopt L-shaped integrated steel roll-formed profiles, and the central connecting beam adopts product-shaped integrated steel roll-formed profiles.

[0012] Due to the adoption of the above technical solution, the technical progress obtained by the present utility model is: The present utility model discloses an integrated steel roll-formed profile, the cross-section of which is a multi-cavity structure. The three cavities are connected into one body successively through rolling spot welding and laser welding, and all the three cavities are of closed structure, so that the overall profile has sufficient rigidity, strength and bending resistance, realizes the substitution of complex multi-cavity aluminum profile structures, and overcomes the problems of low safety performance, low strength, high cost and the like of aluminum profiles in the prior art. Therefore, the roll-formed profile of the present utility model can provide load-bearing and protection functions for the new energy vehicle battery system structure, resist impact force from front and side collisions, and effectively absorb energy and reduce bending deformation with large intrusion.

[0013] The rolled profile of the present utility model adopts an integrated design concept, and replaces the side beam structure assembled and spliced from traditional simple profiles with "square", "grid-like" and "multi-cell grid-like" cross-sections. The integrated design has a more reasonable structure, uses less material to meet the requirement of lightweight design, reduces offline assembly, splicing and welding processes, improves processing efficiency, reduces processing costs, and greatly saves human, financial and material resources; all outer edge surfaces of the profile are flat surfaces, which makes assembly and connection easier when the profile is used as a battery side beam profile.

[0014] The present utility model further provides a battery case manufactured by using an integrated steel rolled profile, which has the following advantages: (1) Lightweight: The rolled profile of the present utility model adopts a high-strength lightweight material, and combined with the roll forming process, can significantly reduce the mass of the battery case while ensuring the strength of the battery case, thereby increasing the cruising range of new energy vehicles, and has more advantages in lightweight compared with traditional aluminum alloy battery cases; (2) High strength: The integrated roll forming process enables the battery case to have a more compact structure and higher overall strength, which can better protect the safe and stable operation of the battery under various working conditions, and effectively compensates for the deficiency of aluminum alloy battery cases in terms of strength; (3) High production efficiency: The roll forming process is a continuous production mode with high production efficiency, which can meet the demand for large-scale production of new energy vehicles; (4) Good cost effectiveness: Although high-strength lightweight materials are used, due to the high efficiency of the integrated roll forming process and the improvement of material utilization, the overall production cost can be effectively controlled, and the present utility model has certain competitiveness in cost compared with aluminum alloy battery cases; (5) High design flexibility: The roll forming process has strong adaptability to the shape and size of the battery case, and can flexibly adjust the shape and size of the battery case according to the design requirements of different vehicle models and battery packs to meet diversified market demands. Description of Drawings

[0015] Figure 1 is a cross-sectional schematic diagram of Embodiment 1 of the present utility model; Figure 2 is a cross-sectional schematic diagram of Embodiment 2 of the present utility model; Figure 3 is a cross-sectional schematic diagram of Embodiment 3 of the present utility model; Figure 4 is a cross-sectional schematic diagram of Embodiment 4 of the present utility model; Figure 5 is a cross-sectional schematic diagram of Embodiment 5 of the present utility model; Figure 6 is a cross-sectional schematic diagram of Embodiment 6 of the present utility model; Figure 7 is a cross-sectional schematic diagram of Embodiment 7 of the present utility model; Figure 8 is a cross-sectional schematic diagram of Embodiment 8 of the present utility model; Figure 9 This is a cross-sectional schematic diagram of Embodiment 9 of this utility model; Figure 10 This is a cross-sectional schematic diagram of Embodiment 10 of the present utility model; Figure 11 This is a cross-sectional schematic diagram of Embodiment 11 of this utility model; Figure 12 This is a schematic diagram of the battery casing. In the figure, 1 is the first cavity, 1-1 is the first upper wall, 1-2 is the first left side wall, 1-3 is the first lower wall, 1-4 is the first right side wall, 2 is the second cavity, 2-1 is the second upper wall, 2-2 is the second left side wall, 2-3 is the second lower wall, 2-4 is the second right side wall, 3 is the third cavity, 3-1 is the third left side wall, 3-2 is the third lower wall, 4 is the first weld point, 100 is the side beam, and 200 is the central connecting beam. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] An integral steel roll-formed profile is a closed structure consisting of three enclosed rectangular cavities, formed by multiple cold bending processes from a single steel plate. These cavities include a first cavity 1, a second cavity 2, and a third cavity 3. The outer edges of the roll-formed profile are all flat, facilitating assembly and connection.

[0018] The first cavity 1 and the second cavity 2 are rectangular cavities formed by bending both ends of a sheet material, and the structures of the first cavity 1 and the second cavity 2 are similar. The third cavity 3 is formed by bending the middle of a sheet material. The first cavity 1 and the third cavity 3, as well as the second cavity 2 and the third cavity 3, each share a common cavity wall. Both ends of the sheet material are welded and fixed to the cavity wall of the third cavity 3, thereby sealing the first cavity 1 and the second cavity 2. After the third cavity 3 is formed, the two corners of the first cavity 1 and the second cavity 2, after being bent, come into contact and are fixedly connected by welding, thus linking the first cavity 1, the second cavity 2, and the third cavity 3 into a single unit.

[0019] The bending method at both ends of the sheet metal is not strictly limited; simultaneous symmetrical outward bending or bending one side inward and the other side outward (i.e., figure-eight forming) are both acceptable. Different bending methods result in different welding positions at the ends of the sheet metal, but have little impact on the strength of the profile. When using the profile, the choice can be made based on the space requirements of the location where the profile will be used and the difficulty of profile processing.

[0020] The width of the third cavity 3 is not less than the width of the first cavity 1. When the width of the third cavity 3 is the same as the width of the first cavity 1, the first cavity 1 is located directly above the third cavity 3, and the second cavity 2 is located on the horizontal side of the third cavity 3, so that the overall cross-section of the rolled profile is L-shaped, which can be used as a peripheral frame structure of a battery case frame; when the width of the third cavity 3 is greater than the width of the first cavity 1, the rolled profile is in a "product-shaped" structure, which can be used as a central connecting beam structure of a battery case frame.

[0021] The corners of the first cavity 1, the second cavity 2 and the third cavity 3 are all rounded, so that the impact force can be synchronously transmitted along the symmetrically arranged plates when under stress, the stress is more uniform, and there are no obstacles or dead corners.

[0022] Laser welding is preferably adopted for the welding of the corners of the first cavity 1 and the second cavity 2, which has high welding speed and high weld strength, so as to ensure the overall strength of the rolled profile. It should be noted that in the actual processing process, considering the processing difficulty and welding strength, process edges can be formed at the corners of the first cavity 1 / the second cavity 2 to increase the welding contact area and improve the welding strength.

[0023] The welding between the two ends of the plate and the cavity wall of the third cavity 3 can be selected from lap welding, edge hooking welding, bent seam welding or vertical welding. Different welding methods have different connection strengths, which can be selected according to the strength requirements of the specific application purpose of the profile. Single-station double-row roll spot welding is preferred for forming.

[0024] When lap welding is adopted, the lap end can be directly welded to the adjacent cavity wall, or a recessed matching surface can be arranged at the adjacent cavity wall, so that the lap end and the adjacent cavity wall are connected into a plane after welding, so as to meet the requirements of the installation space of the profile.

[0025] When lap welding is adopted, the lap length is not less than 3 times the material thickness, so as to ensure the welding strength and the impact resistance strength of the final profile product.

[0026] The following are embodiments of the integrated steel rolled profile of the present utility model, and appropriate modifications and derivations based on these embodiments are all within the protection scope of the present utility model. Example 1

[0027] An integrated steel rolled profile, see Figure 1It includes a first upper wall 1-1, a first left side wall 1-2, a first lower wall 1-3, a first right side wall 1-4, a second upper wall 2-1, a second left side wall 2-2, a second lower wall 2-3, a second right side wall 2-4, a third left side wall 3-1, and a third lower wall 3-2. The first upper wall 1-1, the first left side wall 1-2, the first right side wall 1-4, and the first lower wall 1-3 together form a first cavity 1; the second upper wall 2-1, the second left side wall 2-2, the second right side wall 2-4, and the second lower wall 2-3 together form a second cavity 2; and the first lower wall 1-3, the third left side wall 3-1, the third lower wall 3-2, and the second left side wall 2-2 together form a third cavity 3.

[0028] As shown in the figure, the first cavity 1 and the second cavity 2 are formed by symmetrically bending the two ends of the sheet metal, and are closed simultaneously. The included angles of the first lower wall 1-3 and the first right side wall 1-4, and the included angles of the second upper wall 2-1 and the second left side wall 2-2 are in contact and fixedly connected by laser welding.

[0029] The first upper wall 1-1 and the first lower wall 1-3 have the same length, the third left side wall 3-1 and the second right side wall 2-4 have the same length, the third cavity 3 is located directly below the first cavity 1, the second left side wall 2-2 and the third left side wall 3-1 are connected to form a plane, and the cross-section of the roll-formed profile is L-shaped.

[0030] In this embodiment, the welding method between the two ends of the sheet metal and the wall of the third cavity 3 is overlay welding. Specifically, the third left side wall 3-1 and the third lower wall 3-2 are inwardly recessed hat-shaped reinforcing rib structures in the early stage of forming. The hat-shaped reinforcing rib structure forms a mating surface with the end of the sheet metal to strengthen the welding connection. The overlay length is not less than 3 times the material thickness to ensure welding strength and impact resistance of the final profile product. Example 2

[0031] See Figure 2 The structure of this embodiment is basically the same as that of Embodiment 1, except that the third left side wall 3-1 and the third lower wall 3-2 are both planar and do not have a hat-shaped reinforcing rib structure. The end of the first left side wall 1-2 is directly stacked and welded to the third left side wall 3-1, and the end of the second lower wall 2-3 is directly stacked and welded to the third lower wall 3-2. Example 3

[0032] See Figure 3 The structure of this embodiment is basically the same as that of embodiment 2, except that the first cavity 1 and the second cavity 2 are closed by different welding methods. This embodiment adopts hook welding.

[0033] Two ends of the plate are bent inward by 90° to form hooked edges respectively. After the first left side wall 1-2 is hooked inward, it is attached to the first lower wall 1-3 for penetration seam welding, and after the second lower wall 2-3 is hooked inward, it is attached to the second left side wall 2-2 for penetration welding.

[0034] When the length of the third lower wall 3-2 is equal to the length of the first upper wall 1-1, it forms as shown in Figure 3 -a, an L-shape; when the length of the third lower wall 3-2 is greater than the length of the first upper wall 1-1, it forms as shown in Figure 3 -b, a "pin" shape. Example 4

[0035] Referring to Figure 4 , the structure of this example is basically the same as that of Example 1, and the difference lies in that the bending mode and closed welding mode of the second cavity 2 are different; asymmetric splayed forming is adopted at both ends of the plate.

[0036] The first cavity 1 is formed by bending the left end of the plate inward, the end of the first left side wall 1-2 and the third left side wall 3-1 are subjected to lap welding, and the third left side wall 3-1 is provided with a cap-shaped reinforcing rib structure matching with the end of the first left side wall 1-2.

[0037] The second cavity 2 is formed by bending the right end of the plate outward, the second lower wall 2-3 and the third lower wall 3-2 form an integral plane. The end of the second left side wall 2-2 is hooked outward by 90°, and is attached to the third lower wall 3-2 for lap penetration welding. Example 5

[0038] Referring to Figure 5 , this example is basically the same as the structure of Example 4 in structure, and the difference lies in that the closed welding mode of the first cavity 1 is different, and hook edge welding is adopted.

[0039] The end of the first left side wall 1-2 is bent inward by 90° to form a hook edge, which is attached to the first lower wall 1-3 for penetration seam welding.

[0040] When the length of the third lower wall 3-2 is equal to the length of the first upper wall 1-1, it forms as shown in Figure 5 -a, an L-shape; when the length of the third lower wall 3-2 is greater than the length of the first upper wall 1-1, it forms as shown in Figure 5 -b, a "pin" shape. Example 6

[0041] Referring to Figure 6 , the structure of this example is basically the same as that of Example 4, and the difference lies in that the closed welding mode of the second cavity 2 is not completely the same, and the hook welding position of the second left side wall 2-2 is different.

[0042] An end of the second left side wall 2-2 is bent inward by 90° to form a hooked edge, which is attached to the third lower wall 3-2 for lap penetration welding. Example 7

[0043] Referring to Figure 7 , the structure of this example is substantially the same as that of Example 6, with the difference that: the first cavity 1 adopts a different closing welding mode, specifically hooked edge welding is used.

[0044] An end of the first left side wall 1-2 is bent inward by 90° to form a hooked edge, which is attached to the first lower wall 1-3 for penetration seam welding.

[0045] When the length of the third lower wall 3-2 is equal to the length of the first upper wall 1-1, an L-shape as shown in Figure 7 -a is formed; when the length of the third lower wall 3-2 is greater than the length of the first upper wall 1-1, a "pin-shaped" structure as shown in Figure 7 -b is formed. Example 8

[0046] Referring to Figure 8 , the structure of this example is substantially the same as that of Example 4, with the difference that: the second cavity 2 adopts a different closing welding mode, specifically vertical welding is used.

[0047] An end of the second left side wall 2-2 is directly attached to the third lower wall 3-2, and vertical penetration welding is adopted. Example 9

[0048] Referring to Figure 9 , the structure of this example is substantially the same as that of Example 8, with the difference that: the first cavity 1 adopts a different closing welding mode, specifically hooked edge welding is used.

[0049] An end of the first left side wall 1-2 is bent inward by 90° to form a hooked edge, which is attached to the first lower wall 1-3 for penetration seam welding.

[0050] When the length of the third lower wall 3-2 is equal to the length of the first upper wall 1-1, an L-shape as shown in Figure 9 -a is formed; when the length of the third lower wall 3-2 is greater than the length of the first upper wall 1-1, a "pin-shaped" structure as shown in Figure 9 -b is formed. Example 10

[0051] Referring to Figure 10 in this example, the cross-sections of the roll-formed profiles are all "pin-shaped", and the closing welding mode of the first cavity 1 is all hooked edge welding, that is, the end of the first left side wall 1-2 is bent outward by 90° to form a hooked edge, which is attached to the part extending from the outer edge of the first lower wall 1-3 to the third cavity 3, and then penetration seam welding is performed.

[0052] as shown in Figure 10-a, two ends of the plate are bent symmetrically. The closed welding mode of the second cavity 2 adopts edge hooking welding, and the second lower wall 2-3 is hooked inward and then fitted with the second left side wall 2-2 for penetration welding.

[0053] As shown in Figure 10 -b, two ends of the plate are bent asymmetrically, and the second lower wall 2-3 and the third lower wall 3-2 form an integral plane. An end portion of the second left side wall 2-2 is hooked by 90° outward, and is fitted with the third lower wall 3-2 for laminated material penetration welding.

[0054] As shown in Figure 10 -c, two ends of the plate are bent asymmetrically, and the second lower wall 2-3 and the third lower wall 3-2 form an integral plane. An end portion of the second left side wall 2-2 is hooked by 90° inward, and is fitted with the third lower wall 3-2 for laminated material penetration welding.

[0055] As shown in Figure 10 -d, two ends of the plate are bent asymmetrically, and the second lower wall 2-3 and the third lower wall 3-2 form an integral plane. A head end of the second left side wall 2-2 is directly fitted with the third lower wall 3-2, and vertical penetration welding is adopted. Example 11

[0056] Referring to Figure 11 , cross-sections of the roll-formed profile in this example are all in a "pin-shaped" structure, the closed welding mode of the first cavity 1 is all vertical welding, the head end of the first left side wall 1-2 is directly fitted with the first lower wall 1-3, and vertical penetration welding is adopted.

[0057] As shown in Figure 11 -a, two ends of the plate are bent symmetrically. The closed welding mode of the second cavity 2 adopts edge hooking welding, and the second lower wall 2-3 is hooked inward and then fitted with the second left side wall 2-2 for penetration welding.

[0058] As shown in Figure 11 -b, two ends of the plate are bent asymmetrically, and the second lower wall 2-3 and the third lower wall 3-2 form an integral plane. An end portion of the second left side wall 2-2 is hooked by 90° outward, and is fitted with the third lower wall 3-2 for laminated material penetration welding.

[0059] As shown in Figure 11 -c, two ends of the plate are bent asymmetrically, and the second lower wall 2-3 and the third lower wall 3-2 form an integral plane. An end portion of the second left side wall 2-2 is hooked by 90° inward, and is fitted with the third lower wall 3-2 for laminated material penetration welding.

[0060] As shown in Figure 11-d, the two ends of the plate are asymmetrically bent and formed, and the second lower wall 2-3 and the third lower wall 3-2 form an integral plane. The end of the second left side wall 2-2 is directly attached to the third lower wall 3-2, and vertical penetration welding is adopted.

[0061] The present utility model also provides a battery case, as Figure 12 shown in the figure, comprises a frame structure formed by four side beams 100 connected end to end, and a central connecting beam 200 is arranged inside the frame structure. The side beam 100 adopts the L-shaped integrated steel roll-formed profile of the present utility model, and the central connecting beam 200 adopts the "pin-shaped" integrated steel roll-formed profile of the present utility model.

[0062] The central connecting beam 200 presents a "cross"-shaped structure formed by intersecting one transverse beam and one longitudinal beam; the number and arrangement of the transverse beams and longitudinal beams can also be adjusted according to the specific structure of the battery to adjust the support structure.

[0063] It should be noted that there is another common battery case structure, which is an integrally stamped battery case with the battery installed in the case. The L-shaped integrated steel roll-formed profile of the present utility model can be used as a support beam and welded to the outer periphery of the integrally stamped battery case to achieve effective protection of the battery.

[0064] The above description is only a preferred embodiment of the present utility model, and all equivalent changes and modifications made in accordance with the scope of the patent application of the present utility model shall fall within the scope of coverage of the present utility model.

Claims

1. A one-piece steel roll-formed profile, characterized in that: The roll-formed profile is a closed structure formed by cold bending a single steel plate for multiple times and comprising three closed rectangular cavities, including a first cavity (1), a second cavity (2) and a third cavity (3); the first cavity (1) and the second cavity (2) are formed by bending both ends of the plate, and a pair of vertex angles of the first cavity (1) and the second cavity (2) are fixedly connected through a first welding spot (4); the third cavity (3) is formed by bending the middle part of the plate, and a shared cavity wall shared by two cavities is respectively provided between the first cavity (1) and the third cavity (3) and between the second cavity (2) and the third cavity (3); all outer edge surfaces of the roll-formed profile are flat surfaces; the width of the third cavity (3) is not less than the width of the first cavity (1).

2. The integrated steel roll-formed profile according to claim 1, characterized in that: The roll-formed profile comprises a first upper wall (1-1), a first left side wall (1-2), a first lower wall (1-3), a first right side wall (1-4), a second upper wall (2-1), a second left side wall (2-2), a second lower wall (2-3), a second right side wall (2-4), a third left side wall (3-1) and a third lower wall (3-2); the first upper wall (1-1), the first left side wall (1-2), the first right side wall (1-4) and the first lower wall (1-3) enclose to form the first cavity (1), and the second upper wall (2-1), the second left side wall (2-2), the second right side wall (2-4) and the second lower wall (2-3) enclose to form the second cavity (2); the first lower wall (1-3), the third left side wall (3-1), the third lower wall (3-2) and the second left side wall (2-2) enclose to form the third cavity (3).

3. The integrated steel roll-formed profile according to claim 2, characterized in that: The included angle between the first lower wall (1-3) and the first right side wall (1-4) and the included angle between the second upper wall (2-1) and the second left side wall (2-2) are fixedly connected through the first welding spot (4).

4. The integrated steel roll-formed profile according to claim 1, characterized in that: When the width of the third cavity (3) is the same as the width of the first cavity (1), the cross-section of the roll-formed profile is L-shaped; when the width of the third cavity (3) is greater than the width of the first cavity (1), the cross-section of the roll-formed profile is in a "pin-shaped" (three stacked squares) configuration.

5. The integrated steel roll-formed profile according to claim 1, characterized in that: Both ends of the plate are respectively welded and fixed to the cavity wall of the third cavity (3), and the welding method can be lap welding, edge hook welding, bent seam welding or vertical welding.

6. The integrated steel roll-formed profile according to claim 5, characterized in that: The third left side wall (3-1) and the third lower wall (3-2) are provided with inwardly recessed hat-shaped reinforcing rib structures, and the hat-shaped reinforcing rib structures and the end of the plate form a mating surface.

7. The integrated steel roll-formed profile according to claim 1, characterized in that: The corners of the first cavity (1), the second cavity (2) and the third cavity (3) are all rounded corners.

8. A battery casing, comprising a frame structure formed by four side beams (100) joined end to end, and a central connecting beam (200) disposed inside the frame structure, characterized in that: The side beam (100) adopts the L-shaped integrated steel roll-formed profile according to any one of claims 1 to 7, and the central connecting beam (200) adopts the "pin-shaped" integrated steel roll-formed profile according to any one of claims 1 to 7.

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