Battery pack box body, preparation method of frame of battery pack box body and vehicle

Abstract

The invention relates to the technical field of automobiles, in particular to a battery pack box body, a preparation method of a framework of the battery pack box body and a vehicle. The embodiment of the invention provides a battery pack box body. The battery pack box body comprises a frame, an upper cover and a bottom plate, the frame comprises a plurality of beams, and at least one beam extending in the width direction of the frame is an aluminum alloy rolling piece with the cross section shaped like a Chinese character'ri '. The upper cover and the bottom plate are located on the two sides of the frame in the height direction respectively. According to the battery pack box body, the preparation method of the frame of the battery pack box body and the vehicle provided by the invention, at least one beam, extending in the width direction of the frame, of the plurality of beams of the frame is the aluminum alloy rolling piece with the cross section in the shape of the Chinese character'ri '; the aluminum alloy rolling part has the advantages of high production efficiency of rolled high-strength steel and light weight of aluminum alloy extruded profiles, so that the production efficiency and the light weight effect of the battery pack box body are improved, and the strength of the battery pack box body is ensured due to the fact that the cross section of the aluminum alloy rolling part is shaped like the Chinese character'ri '.

Description

Technical Field

[0001] The present invention relates to the field of automobile technology, and in particular to a battery pack case, a method for preparing a frame of the battery pack case, and a vehicle. Background Art

[0002] The development of new energy vehicles around the world has entered an irreversible fast lane, and the electrification of automobiles has become a consensus among countries and companies around the world. The power battery box is a key structural component that carries and protects the power battery module of new energy vehicles. It is composed of several beams. However, in related technologies, it is difficult to produce power battery boxes while taking into account both efficiency and lightweight. Summary of the invention

[0003] The present application provides a battery pack case, a method for preparing a frame of a battery pack case, and a vehicle, which solves the technical problems in the related art that the production efficiency of power battery cases is low and the lightweight effect is poor.

[0004] In a first aspect, an embodiment of the present application provides a battery pack case, comprising:

[0005] The frame comprises a plurality of beams, and at least one of the beams extending in the width direction of the frame is an aluminum alloy rolled part with a Japanese-shaped cross section;

[0006] The upper cover and the bottom plate are located on both sides of the frame in the height direction.

[0007] In some embodiments, the frame includes a frame and multiple cross beams, and the multiple cross beams are arranged in the frame at intervals along the length direction of the frame. The cross beam located at the front end divides the inner cavity of the frame into a first installation cavity and a second installation cavity, and the remaining cross beams divide the second installation cavity into a plurality of battery cell compartments for installing battery cells.

[0008] In some embodiments, the frame includes a side cross beam and two side longitudinal beams, the two side longitudinal beams are respectively connected to the side cross beam and the two ends of the cross beam, the cross beam located at the front end is connected to the front end of the side longitudinal beam, and the cross beam and the side cross beam are both aluminum alloy rolled parts with a Japanese-shaped cross section.

[0009] In some embodiments, the height of the crossbeam is less than the height of the frame, and the heights of the plurality of crossbeams are consistent.

[0010] In a second aspect, an embodiment of the present application provides a method for preparing a frame of a battery pack box, the method comprising: preparing beams of the frame; welding the beams to obtain the frame; wherein the preparation process of the aluminum alloy rolled parts with a Japanese-shaped cross section in the beams of the frame comprises:

[0011] Performing multiple first roll-bending operations on the ends of the aluminum alloy sheet material to obtain an aluminum alloy deformed plate; wherein the aluminum alloy deformed plate has reinforcing ribs inside the aluminum alloy rolled part;

[0012] The two sides of the aluminum alloy deformed plate are simultaneously subjected to a plurality of second rolling bends to obtain an aluminum alloy rolled part with a Japanese-shaped cross section; wherein, during the first rolling bend and the second rolling bend, the bending angle of each pass is 5° to 20°, and the difference between two adjacent bending angles is ≤10°

[0013] In some embodiments, in the first roller bending, the number of bending passes is 5 to 6, and the bending angles of the 4th and 5th passes are greater than the bending angles of the other passes.

[0014] In some embodiments, when the number of bending passes of the first roller bending is 6, the bending angles of the 4th and 5th passes are the largest, which are 18° to 20°, and the bending angles of the 1st and 6th passes are the smallest, which are 8° to 10°.

[0015] In some embodiments, in the second roller bending, the number of bending passes is 7 to 8, and the bending angle of the 5th pass is the largest.

[0016] When the number of bending passes of the second roller bending is 7, the bending angles of the 4th pass and the 5th pass are the largest, both of which are 18° to 20°.

[0017] In a third aspect, an embodiment of the present application provides a vehicle, including a battery pack, wherein the battery pack includes the battery pack case described above.

[0018] The beneficial effects of this application are as follows:

[0019] The present application provides a battery pack case, a method for preparing a frame of a battery pack case, and a vehicle. Among the multiple beams of the frame, at least one beam extending along the width direction of the frame is an aluminum alloy rolled part with a S-shaped cross-section. The aluminum alloy rolled part combines the advantages of high production efficiency of rolled high-strength steel and lightweight aluminum alloy extruded profiles, thereby improving the production efficiency and lightweight effect of the battery pack case. Moreover, since the cross-section of the aluminum alloy rolled part is in the S-shape, the strength of the battery pack case is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0021] Figure 1 An exploded view of the battery pack case provided in an embodiment of the present application.

[0022] Figure 2 for Figure 1 Schematic diagram of the structure of the middle frame.

[0023] Figure 3a for Figure 2 Schematic diagram of the cross section of the beam of the middle frame Figure 1 .

[0024] Figure 3b for Figure 2 Schematic diagram of the cross section of the beam of the middle frame Figure 2 .

[0025] Figure 3c for Figure 2 Schematic diagram of the cross section of the beam of the middle frame III.

[0026] Figure 3d for Figure 2 Schematic diagram of the cross section of the beam of the middle frame Figure 4 .

[0027] Figure 4 A flow chart of a process for preparing an aluminum alloy rolled part having a Japanese-shaped cross section provided in an embodiment of the present application.

[0028] Figure 5 for Figure 4 Schematic diagram of the rolling process of the aluminum alloy sheet in step S100.

[0029] Figure 6 for Figure 4 Schematic diagram of the rolling process of the aluminum alloy deformed plate in step S200 Figure 1 .

[0030] Figure 7 for Figure 4 Schematic diagram of the rolling process of the aluminum alloy deformed plate in step S200 Figure 2 .

[0031] Figure 8 for Figure 2 Schematic diagram of the splicing of the side cross beams and side longitudinal beams of the middle frame.

[0032] Description of reference numerals:

[0033] 10-battery pack body, 100-frame, 110-frame, 111-side longitudinal beam, 112-side cross beam, 113-first installation cavity, 114-second installation cavity, 120-cross beam, 121-battery cell compartment, 122-aluminum alloy deformation plate, 130-front frame beam, 140-front frame reinforcement beam, 150-first lifting ear, 160-second lifting ear, 200-upper cover, 300-bottom plate. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0036] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0037] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] In the early stage of new energy vehicle development, the energy density of the battery cell was relatively small. In order to pursue lightweight and overcome mileage anxiety, the battery box will use more lightweight materials, such as aluminum die castings, aluminum stampings, aluminum extruded profiles, carbon fiber, etc. With the increase of battery cell energy density, vehicle manufacturers pay more attention to the balance of cost, performance, safety and cruising range of battery boxes, and put forward the technical solution of roll-pressed high-strength steel battery boxes, but the extruded aluminum profile battery box is still the mainstream technical route for electric vehicle boxes. The extruded aluminum alloy profile box is welded by extruding aluminum alloy profiles with different geometric sections. Its advantages are lightweight, simple structure and low extrusion die cost. Its disadvantages are that it is difficult to extrude some complex geometric sections or high-strength aluminum alloys, resulting in low production efficiency. The roll-pressed high-strength steel box is formed by rolling high-strength steel tube beams with different cross-sections, and then welded. It has high production efficiency, obvious cost advantages and long die life, but the lightweight effect is poor compared to the extruded aluminum profile box.

[0039] In order to improve the above technical problems to a certain extent, the embodiments of the present application provide a battery pack case, a method for preparing a frame of a battery pack case, and a vehicle, which can improve the production efficiency and lightweight effect of the battery pack case and ensure the strength of the battery pack case.

[0040] The following is an explanation of the embodiments of the present application with reference to the pictures:

[0041] See also Figure 1-Figure 3a The embodiment of the present application provides a battery pack box 10, including a frame 100, an upper cover 200 and a bottom plate 300. The frame 100 includes a plurality of beams, and at least one beam extending along the width direction of the frame 100 is an aluminum alloy rolled part with a Japanese-shaped cross section; the upper cover 200 and the bottom plate 300 are respectively located on both sides of the frame 100 in the height direction.

[0042] The frame 100 supports the entire battery pack and ensures the structural strength of the entire battery pack. The upper cover 200 is placed on the top of the frame 100, and the bottom plate 300 is placed on the bottom of the frame 100, so that the frame 100, the upper cover 200 and the bottom plate 300 together define a cell compartment 121 for installing a cell group. The cell group is supported on the bottom plate 300, and the bottom plate 300 supports the cell group.

[0043] Among them, the bottom plate 300 is sealedly connected to the bottom of the frame 100, and the upper cover 200 is also sealedly connected to the top of the frame 100, so that the battery cell compartment 121 is a sealed space, ensuring that the environment inside the battery cell compartment 121 is stable and not affected by the external environment, so as to improve the stability of the battery cell operation.

[0044] The frame 100 is composed of several connected beams, and at least one beam extending along the width direction of the frame 100 is an aluminum alloy rolled piece with a "day" - shaped cross - section. That is, it can be one beam extending along the width direction of the frame 100 being an aluminum alloy rolled piece with a "day" - shaped cross - section, or two, three, or even all the beams extending along the width direction of the frame 100 being aluminum alloy rolled pieces with a "day" - shaped cross - section. There is no restriction on this.

[0045] The aluminum alloy rolled piece is made by rolling an aluminum alloy blank. The rolling process has high production efficiency, and the aluminum alloy is light in weight. Therefore, the aluminum alloy rolled piece combines the advantages of high production efficiency of rolled high - strength steel and lightweight of aluminum alloy extruded profiles. Thus, by using aluminum alloy rolled pieces in the frame 100, the production efficiency and lightweight effect of the battery pack box 10 can be improved. And because the cross - section of the aluminum alloy rolled piece is "day" - shaped, the strength of the battery pack box 10 is ensured.

[0046] Of course, the remaining beams of the frame 100 can also all be aluminum alloy rolled pieces, that is, the whole frame 100 is made of aluminum alloy rolled pieces, thereby further improving the production efficiency and lightweight effect of the battery pack box 10.

[0047] Please refer to Figure 3a , the cross - section is "day" - shaped, that is, the cross - section includes two long ribs, two short ribs, and one reinforcing rib. The two long ribs and the two short ribs enclose a rectangle, and the reinforcing rib is located between the two long ribs and perpendicular to the two long ribs. The "day" - shaped cross - section has high bending and torsional resistance due to its unique geometric shape. This enables it to show high strength and stiffness when bearing loads and be able to withstand large forces.

[0048] It should be noted that the length direction, width direction, and height direction of the frame 100 are the same as those of the battery pack box 10, and when the battery pack box 10 is installed on a vehicle, the length direction, width direction, and height direction of the battery pack box 10 are also the same as those of the vehicle. In this field, the vehicle length direction is usually called the X - direction or longitudinal direction, the vehicle width direction is called the Y - direction or transverse direction, and the vehicle height direction is called the Z - direction or vertical direction. Correspondingly, the length direction of the battery pack is parallel to the X - direction, the width direction is parallel to the Y - direction, and the height direction is parallel to the Z - direction.

[0049] Since the length dimension of the vehicle is much larger than the width dimension, that is, the distance between the battery pack box 10 and the side of the vehicle is less than the distance between the battery pack box 10 and the front - rear of the vehicle. Therefore, when the vehicle is impacted in the width direction, the damage to the battery pack box 10 is greater than when the vehicle is impacted in the length direction. Since the beams extending along the width direction of the frame 100 are used to bear the side impact force, their strength requirements are higher. Therefore, at least one beam extending along the width direction of the frame 100 has a "day" - shaped cross - section.

[0050] See also Figure 2 In some embodiments, the frame 100 includes a frame 110 and a plurality of beams 120. The plurality of beams 120 are arranged in the frame 110 at intervals along the length direction of the frame 100. The beam 120 at the front end divides the inner cavity of the frame 110 into a first installation cavity 113 and a second installation cavity 114. The remaining beams 120 divide the second installation cavity 114 into a plurality of battery cell compartments 121 for installing battery cell groups.

[0051] The frame 110 is used to connect with the upper cover 200 and the lower plate. The cross beam 120 is a beam arranged along the width direction of the frame 100. The multiple cross beams 120 can all be aluminum alloy rolled parts with a Japanese-shaped cross section.

[0052] For the convenience of description, when the battery pack case 10 is installed in the vehicle, the forward driving direction of the vehicle is defined as forward. Since the crossbeam 120 at the front end divides the inner cavity of the frame 110 into a first installation cavity 113 and a second installation cavity 114, the functional area division inside the battery pack case 10 is realized, and the space utilization and safety are improved. The first installation cavity 113 is used to install circuit components, and the second installation cavity 114 is used to install battery cells, which separates the circuit elements from the battery cells, avoids the risk of short circuits that may be caused by direct contact, and facilitates the maintenance and management of circuit components.

[0053] The remaining cross beams 120 divide the second installation cavity 114 into a plurality of battery cell compartments 121 so that a plurality of battery cell groups can be installed in the plurality of battery cell compartments 121 , which not only facilitates the installation and management of the battery cell groups but also improves the energy density and overall performance of the battery pack.

[0054] See also Figure 2 In some embodiments, the frame 110 includes a side cross beam 112 and two side longitudinal beams 111. The two side longitudinal beams 111 are respectively connected to the two ends of the side cross beam 112 and the cross beam 120. The cross beam 120 at the front end is connected to the front end of the side longitudinal beam 111. The cross beam 120 and the side cross beam 112 are both aluminum alloy rolled parts with a Japanese-shaped cross section.

[0055] The side cross beam 112 and multiple cross beams 120 are all located between the two side longitudinal beams 111 and are perpendicular to the side longitudinal beams 111. The side cross beam 112 is located at the rear end of the side longitudinal beam 111. Since the cross beam 120 at the front end is connected to the front end of the side longitudinal beam 111, the two side longitudinal beams 111, the side cross beam 112 and the cross beam 120 at the front end together form a second installation cavity 114. Since the side cross beam 112 also needs to withstand the impact force on the side, the cross beam 120 and the side cross beam 112 are both aluminum alloy rolled parts with a Japanese-shaped cross section to improve the side bearing capacity of the battery pack box 10.

[0056] Of course, the side longitudinal beam 111 can also be an aluminum alloy rolled part with a Japanese-shaped cross section to improve the bearing capacity of the battery pack body 10 in the front and rear directions and provide the best protection for the battery cell group.

[0057] The crossbeam 120 at the rearmost end may be arranged in close contact with the side crossbeam 112 , thereby reducing useless space and allowing the battery cell group to maximize the use of the space in the second installation cavity 114 .

[0058] The frame 110 further includes a plurality of front frame beams 130, which together with the cross beam 120 at the front end form a first installation cavity 113. In order to enhance the strength of the first installation cavity 113, a plurality of crisscrossing front frame reinforcement beams 140 are further disposed in the first installation cavity 113, and the plurality of front frame reinforcement beams 140 are connected to the front frame beams 130. Since the first installation cavity 113 is used to install circuit components, which are less susceptible to damage than battery cells, the strength requirements of the front frame beams 130 and the front frame reinforcement beams 140 may be lower than those of the cross beams 120. Please refer to Figure 3b In order to simplify the process and improve production efficiency, the front frame beam 130 and the front frame reinforcement beam 140 can be aluminum alloy rolled parts with a rectangular cross-section.

[0059] Specifically, there are three front frame beams 130 , and the three front frame beams 130 and the cross beam 120 at the front end form a trapezoidal first installation cavity 113 .

[0060] Since the battery panel box is usually heavy, in order to provide a stable hanging point for the battery pack box 10 and ensure safety and reliability during transportation and installation, the frame 110 also includes a plurality of first hanging ears 150 and a second hanging ear 160. The plurality of first hanging ears 150 are connected to the side longitudinal beam 111, and the plurality of second hanging ears 160 are connected to the front frame beam 130. Specifically, the cross-sections of the first hanging ears 150 and the second hanging ears 160 may have an opening, and the first hanging ears 150 may have a cross-section such as Figure 3c The aluminum alloy rolled part shown in FIG. 1 may have a second lifting ear 160 with a cross section as shown in FIG. Figure 3d The aluminum alloy rolled part shown.

[0061] See also Figure 2 In some embodiments, the height of the crossbeam 120 is less than the height of the frame 110 , and the heights of the multiple crossbeams 120 are consistent.

[0062] Since the upper part of the frame 110 needs to be connected to the upper cover 200, and components such as a fireproof plate and a current detection circuit need to be arranged above the battery cell group, the height of the frame 110 needs to be higher than the height of the beam 120 to leave space for arranging other components.

[0063] Since multiple cross beams 120 divide the second installation cavity 114 into several battery cells compartments 121 for installing battery cell groups, both ends of the battery cell group are in contact with two adjacent cross beams 120 respectively, and the two adjacent cross beams 120 compress the battery cell group. Since the heights of multiple cross beams 120 are the same, that is, the cross-sectional areas of multiple cross beams 120 are the same, the contact areas between both ends of the battery cell group and the cross beams 120 are the same, and the pressures received by both ends of the battery cell group are the same. The uniform stress on the battery cell group helps to maintain the stability of the internal structure of the battery cell group, thereby extending the service life of the battery cell group.

[0064] Based on the same inventive concept, please refer to Figure 4-Figure 7 , an embodiment of the present application further provides a method for manufacturing a frame 100 of a battery pack housing 10. The manufacturing method includes: manufacturing each beam of the frame 100; welding each beam together to obtain the frame 100. Among them, in each beam of the frame 100, the manufacturing process of the aluminum alloy rolling part with a "day" - shaped cross section includes:

[0065] S100: Perform multiple passes of first rolling and bending on the end of the aluminum alloy sheet to obtain an aluminum alloy deformed sheet 122; among them, the aluminum alloy deformed sheet 122 has a reinforcing rib inside the aluminum alloy rolling part.

[0066] Among the beams of the frame 100, the side cross beams 112, side longitudinal beams 111, and cross beams 120 are all aluminum alloy rolling parts with a "day" - shaped cross section, so as to improve the bearing capacity of the battery pack housing 10 and provide the best protection effect for the battery cell group.

[0067] The reinforcing rib inside the aluminum alloy rolling part is the reinforcing rib inside the aluminum alloy rolling part with a "day" - shaped cross section. The cross section is in the shape of a "day", that is, the cross section includes two long ribs, two short ribs, and one reinforcing rib. The two long ribs and two short ribs enclose a rectangle, and the reinforcing rib is located between the two long ribs and perpendicular to the two long ribs.

[0068] When rolling the end of the aluminum alloy sheet, the aluminum alloy sheet needs to be placed in a pre - set roll gap, and the aluminum coil is constrained and pulled by the deformation rolls and auxiliary rolls arranged up, down, left, and right. After multiple passes of continuous rolling, the required geometric cross - sectional shape is obtained. The thickness of the aluminum alloy sheet used can be 2.0 mm - 2.5 mm, and the tensile strength can be 200 MPa - 300 MPa.

[0069] Please refer to Figure 5The initial state of the end of the aluminum alloy sheet is horizontal. During rolling, the upper and lower symmetrical auxiliary rollers are first used to constrain the middle area of ​​the aluminum alloy sheet. Under the action of friction, the high-speed rotating roller surface pulls the aluminum alloy sheet forward. At the same time, the deformation rollers on both sides apply deformation force to the end of the aluminum alloy sheet. After multiple continuous bendings, the end of the aluminum alloy sheet is perpendicular to the middle part of the aluminum alloy sheet. At this time, the end of the aluminum alloy sheet forms a reinforcing rib inside the aluminum alloy rolled part.

[0070] Of course, both ends of the aluminum alloy sheet are provided with overlapping edges. After the aluminum alloy sheet is rolled, the two overlapping edges need to be welded to form the aluminum alloy rolled part.

[0071] In some embodiments, in the first roller bending, the number of bending passes is 5 to 6, and the bending angles of the 4th and 5th passes are greater than the bending angles of the other passes.

[0072] Aluminum alloy sheets will undergo plastic deformation when bent, but this deformation is limited. If the bending angle is too large at one time, it may exceed the plastic deformation capacity of the material, causing the material to break or crack. In addition, aluminum alloy sheets will rebound after bending, that is, the material will partially return to its original state. If the single bending angle is too large, the actual angle after rebound may not meet the design requirements, affecting the accuracy of the product. Therefore, during the rolling process, the bending angle each time should not be too large. In the process of bending the end of the aluminum alloy sheet from 0° to 90°, the bending passes are 5 to 6 times, which can ensure the stability of the forming process and the quality of the final product.

[0073] The 4th and 5th passes are the middle and later passes. Due to the material hardening effect, during the first few bending processes, the material may increase its yield strength due to cold work hardening, which may result in a larger angle being required to achieve the same deformation effect during subsequent bending. In addition, during the bending process, the material may rebound after bending due to elastic recovery, resulting in the actual angle being smaller than expected. As the number of bendings increases, this rebound phenomenon may be gradually overcome, so the angle may be larger in the middle and later bends. Therefore, when the number of bending passes is 5 to 6, the bending angles of the 4th and 5th passes are greater than those of other passes.

[0074] In some embodiments, when the number of bending passes of the first roller bending is 6, the bending angles of the 4th and 5th passes are the largest, which are 18° to 20°, and the bending angles of the 1st and 6th passes are the smallest, which are 8° to 10°.

[0075] In the first pass of roll forming, a smaller bending angle allows the material to gradually adapt to the roll forming process, avoiding excessive plastic deformation of the material at the beginning, which can reduce the risk of material rupture and cracking. A smaller bending angle in the last pass enables more precise control of the forming angle in the final bending pass, ensuring the shape and dimensional accuracy of the final product. Therefore, the bending angles in the first pass and the sixth pass are the smallest.

[0076] S200: Simultaneously perform multiple passes of second roll bending on both sides of the aluminum alloy deformed plate 122 to obtain an aluminum alloy rolled part with a cross-section in the shape of a Chinese character 'Ri'; wherein, during the first roll bending and the second roll bending processes, the bending angle for each pass is 5° - 20°, and the difference between two adjacent bending angles ≤ 10°.

[0077] After the reinforcing ribs inside the aluminum alloy rolled part are roll formed, multiple passes of second roll bending can be simultaneously performed on both sides of the aluminum alloy deformed plate 122 to roll form two long ribs and two short ribs of the aluminum alloy rolled part on the aluminum alloy deformed plate 122.

[0078] Specifically, please refer to Figure 6 , adjust the position of the deformation roller, offset the bending area inward, and through multiple consecutive bends, form the aluminum alloy deformed plate 122 into a semi-closed C shape. Then, please refer to Figure 7 , further bend the aluminum alloy deformed plate 122 into a closed 'Ri' shape. Performing roll forming on both sides of the aluminum alloy deformed plate 122 can improve production efficiency and make the aluminum alloy deformed plate 122受力均匀.

[0079] Exemplarily, during the first roll bending and the second roll bending processes, the bending angle for each pass can be 8°, 10°, 12°, 15°, 18°, and the difference between two adjacent bending angles can be 5°, 6°, 7°, 8°, 9°.

[0080] In some embodiments, in the second roll bending, the number of bending passes is 7 - 8, and the bending angle in the fifth pass is the largest.

[0081] When the number of bending passes is 7 - 8, the fifth pass is a pass closer to the middle. Due to the work hardening effect of the material, during the previous bending processes, the material may increase its yield strength due to cold work hardening, which may result in a larger angle being required in subsequent bending to achieve the same deformation effect. And during the bending process, the material may spring back after bending due to elastic recovery, resulting in an actual angle smaller than expected. As the number of bending passes increases, this spring-back phenomenon may be gradually overcome. Therefore, in the bending of the pass closer to the middle, the angle may be larger. Consequently, when the number of bending passes is 7 - 8, the bending angle in the fifth pass is greater than that of other passes.

[0082] Specifically, when the number of bending passes of the second roller bending is 7, the bending angles of the 4th pass and the 5th pass are the largest, both of which are 18° to 20°.

[0083] It should be noted that, among the beams in the frame 100, aluminum alloy rolled parts with other cross-sectional shapes (such as the front frame beam 130, the front frame reinforcement beam 140, the first lifting ear 150, and the second lifting ear 160) can also be prepared in the above manner by adjusting the rolled portion accordingly according to the shape of the cross-sectional shape.

[0084] In some embodiments, connecting a plurality of aluminum alloy rolled parts specifically comprises:

[0085] After the aluminum alloy rolled part is prepared, it is cut into required lengths according to the sizes of the beams in the frame 100 to obtain the beams in the frame 100 .

[0086] After obtaining the beams in the frame 100, it is necessary to use a laser cutting machine to cut out the required holes. In addition to opening holes, for two beams that need to be vertically spliced, such as the side cross beam 112 and the side longitudinal beam 111, it is necessary to cut at the overlap of the side cross beam and the side longitudinal beam. Please refer to Figure 8 The cutting angle of the aluminum alloy deformed plate 122 can be 45° to ensure good subsequent assembly.

[0087] After the holes are drilled, referring to the arrangement structure in the frame 100 of the battery pack body 10, multiple aluminum alloy rolled parts are assembled and welded by a clamp to obtain the frame 100. Among them, the gap between two adjacent aluminum alloy rolled parts is ±1.2mm, the welding current is 115A~135A, the welding voltage is 18v~19v, and the welding rate is 45~55cm / min.

[0088] Adjacent beam structures can be connected together by cold metal transition welding in a protective gas of 99.99% Ar. In order to reduce stress concentration, welding is preferentially performed in areas with sudden structural changes, such as corners; in order to reduce the overall deformation of the battery box, left and right cross welding is performed according to the part structure, and then, for the welds on the assembly surface, grinding is performed after cold metal transition welding to remove the weld excess height.

[0089] In some embodiments, the preparation process of the upper cover 200 and the bottom plate 300 is:

[0090] (1) Blanking: The upper cover 200 is provided with a left-right symmetrical dimple structure, which can improve the structural strength and rigidity of the upper cover 200. According to the shape of the upper cover 200, the optimal blanking scheme is determined, and a 1.2 mm thick T4 state 6 series aluminum plate with a tensile strength of ≥200 MPa and an elongation after fracture of ≥20% is used to separate the plates of the required size and shape in the blanking die.

[0091] (2) Stamping: Place the aluminum sheet in a stamping die and perform stamping according to the set process parameters. Due to the difference in physical properties between steel and aluminum, for example, the elastic modulus of aluminum is one-third of that of steel, and the elongation and forming limit of aluminum are lower than those of steel. As a result, the springback of aluminum stamping is greater than that of steel, and it is more prone to wrinkling and cracking.

[0092] (3) Trimming: Use the trimming die to cut off the excess waste on the edge of the aluminum stamping part, and use an air gun to clean the aluminum debris generated during the trimming process in time;

[0093] (4) Punching: In order to realize the assembly connection between the upper cover 200 and the frame 100, a group of assembly holes with a radius of 3.5 mm and evenly distributed spacing are punched out 7.5 mm away from the edge of the upper cover 200, and the spacing between adjacent assembly holes is between 60-90 mm.

[0094] (5) Cleaning and grinding burrs: The oxide scale and oil stains of the aluminum upper cover 200 are removed by acid washing and alkaline washing in sequence, and then the incision position is ground to remove burrs.

[0095] In some embodiments, after the upper cover 200 , the frame 100 , and the bottom plate 300 are prepared, the upper cover 200 , the frame 100 , and the bottom plate 300 may be assembled together to form a battery pack body 10 .

[0096] The upper cover 200 and the box body can be connected by bolts and nuts, and a gasket can be added between the bolts and nuts to ensure air tightness. Stir friction welding can be used to achieve the connection between the bottom plate 300 and the frame 110 of the battery pack box body 10, which can ensure both connection strength and air tightness. Exemplarily, the stir friction welding process parameters are: stirring head speed 1100-1300r / min, welding speed 500-700mm / s.

[0097] Since each beam of the frame 100 of the battery pack case 10 has an aluminum alloy rolled part, the aluminum alloy rolled part combines the advantages of high production efficiency of rolled high-strength steel and lightweight of aluminum alloy extruded profiles. Therefore, the frame 100 uses an aluminum alloy rolled part to improve the production efficiency and lightweight effect of the battery pack case 10, and since the cross-section of the aluminum alloy rolled part is in the shape of a Japanese character, the strength of the battery pack case 10 is ensured.

[0098] Based on the same inventive concept, the embodiment of the present application also provides a vehicle, including a battery pack, which includes the above-mentioned battery pack box 10. The beneficial effects of the vehicle provided by the embodiment of the present application are the same as the beneficial effects of the above-mentioned battery pack box 10, which will not be repeated here.

[0099] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0100] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A battery pack box, characterized in that: include: The frame comprises a plurality of beams, and at least one of the beams extending in the width direction of the frame is an aluminum alloy rolled part with a Japanese-shaped cross section; The upper cover and the bottom plate are located on both sides of the frame in the height direction.

2. The battery pack case according to claim 1, characterized in that: The frame includes a frame and multiple cross beams, and the multiple cross beams are arranged in the frame at intervals along the length direction of the frame. The cross beam located at the front end divides the inner cavity of the frame into a first installation cavity and a second installation cavity, and the remaining cross beams divide the second installation cavity into a plurality of battery cell compartments for installing battery cells.

3. The battery pack case according to claim 2, characterized in that: The frame includes a side crossbeam and two side longitudinal beams, the two side longitudinal beams are respectively connected to the side crossbeam and the two ends of the crossbeam, the crossbeam located at the front end is connected to the front end of the side longitudinal beam, and the crossbeam and the side crossbeam are both aluminum alloy rolled parts with a Japanese-shaped cross section.

4. The battery pack case according to claim 2, characterized in that: The height of the crossbeam is smaller than the height of the frame, and the heights of the plurality of crossbeams are consistent.

5. A method for preparing a frame of a battery pack box, characterized in that: The preparation method comprises: preparing each beam of the frame; welding each beam to obtain the frame; wherein the preparation process of the aluminum alloy rolled parts with a Japanese-shaped cross section in each beam of the frame comprises: Performing multiple first roll-bending operations on the ends of the aluminum alloy sheet material to obtain an aluminum alloy deformed plate; wherein the aluminum alloy deformed plate has reinforcing ribs inside the aluminum alloy rolled part; The two sides of the aluminum alloy deformed plate are simultaneously subjected to multiple passes of second rolling bending to obtain an aluminum alloy rolled part with a Japanese-shaped cross section; wherein, during the first rolling bending and the second rolling bending process, the bending angle of each pass is 5° to 20°, and the difference between two adjacent bending angles is ≤10°.

6. The method for preparing the frame of the battery pack box according to claim 5, characterized in that: In the first roller bending, there are 5 to 6 bending passes, and the bending angles of the 4th and 5th passes are greater than the bending angles of the other passes.

7. The method for preparing the frame of the battery pack box according to claim 6, characterized in that: When the number of bending passes of the first roller bending is 6, the bending angles of the 4th and 5th passes are the largest, which are 18° to 20°, and the bending angles of the 1st and 6th passes are the smallest, which are 8° to 10°.

8. The method for preparing the frame of the battery pack box according to claim 5, characterized in that: In the second roller bending, the number of bending passes is 7 to 8, and the bending angle of the 5th pass is the largest.

9. The method for preparing the frame of the battery pack box according to claim 8, characterized in that: When the number of bending passes of the second roller bending is 7, the bending angles of the 4th pass and the 5th pass are the largest, both of which are 18° to 20°.

10. A vehicle, characterized in that: Comprising a battery pack, the battery pack comprising a battery pack case as described in any one of claims 1-4.

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