Frame type battery box body with good sealing performance and assembling method of frame type battery box body

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a frame type battery box body with good sealing performance and an assembling method thereof, the assembling method comprises two steps of obtaining parts of the frame type battery box body and assembling the frame type battery box body, and the frame type battery box body assembled by the method has good sealing performance on the aspect of structural design. And through the reasonable layout and connection mode of the supporting plate and the bottom protection plate, the overall stability and impact resistance of the box body are effectively enhanced. In the aspect of sealing performance, the first sealing piece and related bolt connection between the bottom protection plate and the frame, the riveting and bolt connection between the supporting plate and the frame and the bottom protection plate, and the sealing pieces are matched, so that the waterproof, dustproof, sound insulation and vibration isolation effects are greatly improved, external water vapor, dust and other impurities are effectively prevented from entering, the risks of battery short circuit, corrosion, poor heat dissipation and the like are reduced, and the service life is prolonged. Safe and stable operation of the battery is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries, and in particular relates to an assembling method of a frame-type battery box with good sealing performance. Background Art

[0002] In today's era of rapid technological development, battery technology, as a key support in many fields, has attracted much attention. The performance of the battery box, as an important protective shell of the battery system, directly affects the overall performance and service life of the battery. Especially in scenarios where batteries are used on a large scale, such as electric vehicles and energy storage power stations, the requirements for battery boxes are becoming increasingly stringent.

[0003] In the complex and ever-changing actual use environment, the battery box may encounter various external factors. For example, in a humid environment, water vapor can easily penetrate into the interior through the gaps in the box. The presence of water vapor may not only cause a short circuit inside the battery, affecting the normal charging and discharging function of the battery, but may also cause corrosion of the battery electrodes, reducing the performance and life of the battery. At the same time, dust is also a problem that cannot be ignored. After a large amount of dust enters the box, it may accumulate on the surface of the battery, affecting the heat dissipation efficiency of the battery, and then causing local overheating of the battery, creating safety hazards. Summary of the invention

[0004] In order to overcome the problems existing in the related art, the present invention discloses a frame-type battery box with good sealing performance and an assembly method thereof, which improves the sealing performance of the box by optimizing the structural design and ensures the stable operation of the battery pack in harsh environments.

[0005] To achieve the above object, a technical solution adopted by the present invention is:

[0006] A method for assembling a frame-type battery box with good sealing performance comprises the following steps:

[0007] S1. Provide a frame, a bottom plate and a sealing assembly; wherein the frame includes a surrounding frame, and the sealing assembly includes a first sealing member;

[0008] S2. Assembling: arranging the first sealing member at the periphery of the lower end of the surrounding frame, and pressing the bottom plate onto the first sealing member, and then fixing the bottom plate to the frame, thereby sealing the connection between the frame and the bottom plate.

[0009] Furthermore, the frame further comprises a crossbeam; the sealing assembly further comprises a second sealing member;

[0010] In step S2, it also includes: arranging a second sealing member at the connection between the cross beam and the bottom plate, and fixing the bottom plate to the lower end of the cross beam, thereby sealing the connection between the cross beam and the bottom plate.

[0011] Furthermore, the step S1 further includes providing a first bolt and a first protective structure; the bottom plate includes a support plate and a bottom guard plate, the bottom guard plate has a peripheral portion that exceeds the peripheral edge of the support plate and is arranged opposite to the surrounding frame, the peripheral portion of the bottom guard plate is provided with a plurality of first through holes, the surrounding frame has first threaded blind holes corresponding to the plurality of first through holes one by one, and the first sealing member has second through holes corresponding to the plurality of first through holes one by one;

[0012] In step S2, it specifically includes:

[0013] S21: fixing the support plate to the surrounding frame and the crossbeam;

[0014] S22: arranging the first sealing member at the periphery of the lower end of the enclosure frame, aligning the plurality of the second through holes with the plurality of the first threaded blind holes one by one, and arranging the second sealing member at the position where the support plate is connected to the bottom guard plate;

[0015] S23: Pressing the bottom guard plate onto the first sealing member and the second sealing member so that the first through holes are aligned one by one with the second through holes;

[0016] S24: Assemble the first bolt onto the first protective structure, and then sequentially pass the first bolt through the first through hole and the second through hole and threadably fix the first bolt to the first threaded blind hole.

[0017] Furthermore, the step S1 further includes: providing a first rivet, the first rivet having a first threaded blind hole; the surrounding frame having third through holes corresponding to the first through holes, each of the third through holes being riveted with a first rivet;

[0018] The step S24 specifically includes: assembling the first bolt onto the first protective structure, and then sequentially passing the first bolt through the first through hole and the second through hole and threading the first bolt into the first threaded blind hole of the first rivet.

[0019] Furthermore, the lower end of the surrounding frame and the lower end of the crossbeam each have a plurality of fifth through holes, and the support plate has fourth through holes corresponding one-to-one to the plurality of the fifth through holes;

[0020] The step S1 further includes: providing a second rivet;

[0021] In step S21, it specifically includes:

[0022] S211: placing the support plate at the lower end of the surrounding frame so that the plurality of fourth through holes are aligned one by one with the plurality of fifth through holes;

[0023] S212: Weld the support plate to the surrounding frame by friction stir welding, and insert a second rivet into the fourth through hole and the fifth through hole and rivet them, so as to fix the support plate to the surrounding frame and the crossbeam.

[0024] Furthermore, the second rivet has a second threaded blind hole, and the bottom guard plate has a plurality of sixth through holes corresponding to some of the fourth through holes at positions corresponding to the crossbeams;

[0025] The step S1 further includes: providing a second bolt and a second protective structure;

[0026] In step S24, it also includes: assembling the second bolt onto the second protective structure, and then passing the second bolt through the sixth through hole and threading it with the second threaded blind hole.

[0027] Furthermore, the second sealing member has a mounting through hole;

[0028] The S22 step is specifically as follows: arrange the first seal at the periphery of the lower end of the frame, align the plurality of the second through holes with the plurality of the first threaded blind holes one by one, and arrange the second seal at the position where the support plate is connected to the bottom guard plate, and align the installation through holes of the plurality of the second seals with the plurality of the sixth through holes one by one.

[0029] Furthermore, step S1 further includes: obtaining an insulating layer;

[0030] Before step S22, it also includes:

[0031] S22a: Form an insulating layer on the side of the support plate close to the bottom guard plate and the side close to the frame by coating or spraying.

[0032] Furthermore, step S1 further includes: obtaining a buffer pad and a protective layer;

[0033] Before step S23, the method further includes:

[0034] S23a: Arrange the buffer pad on the inner side of the bottom guard plate;

[0035] S23b: Arrange the protective layer on the side of the bottom guard plate away from the frame.

[0036] The present invention also provides a frame-type battery box with good sealing performance, which is assembled by any of the above-mentioned assembly methods.

[0037] The present invention discloses an assembly method of a frame-type battery box with good sealing performance, and the frame-type battery box assembled by this method has many beneficial effects. In terms of structural stability, the combination of stir friction welding and rivet fixings makes the connection of each component tight and reliable, and can withstand large external force impact and vibration, ensuring the structural integrity of the box during transportation and use. At the same time, the special frame design and reasonable bolt connection layout effectively reduce the overall weight under the premise of ensuring strength, improve energy utilization efficiency, and facilitate the application and promotion of battery boxes in new energy equipment. In terms of sealing and protection performance, the synergistic effect of sealing components, protective structures and friction welding forms a strict protection system, which not only prevents the invasion of impurities such as water vapor and dust from the outside, but also effectively isolates noise and vibration, creating a stable and clean working environment for the battery pack, greatly extending the service life of the battery pack and improving its working performance. The setting of the protective layer further enhances the wear resistance and corrosion resistance of the bottom guard plate, improves the durability and reliability of the box as a whole, can adapt to a variety of complex and harsh working environments, and reduces maintenance costs and frequencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0039] Figure 1 A three-dimensional diagram of an embodiment of a frame-type battery box with good sealing performance according to the present invention;

[0040] Figure 2 A top view of an embodiment of a frame-type battery box with good sealing performance according to the present invention;

[0041] Figure 3 for Figure 2 A schematic diagram of the structure enlarged at B in the middle;

[0042] Figure 4 for Figure 2 Sectional view along AA direction;

[0043] Figure 5 for Figure 4 A schematic diagram of the structure enlarged at C in the middle;

[0044] Figure 6 for Figure 5 A schematic diagram of the structure at D in the middle is enlarged;

[0045] Figure 7 for Figure 6 A schematic diagram of the structure enlarged at E in the middle;

[0046] Figure 8 for Figure 7A schematic diagram of the structure enlarged at F in the middle;

[0047] Fig. 9 for Figure 2 Schematic diagram after hiding the bottom guard plate and protective layer;

[0048] Fig.10 for Fig. 9 A schematic diagram of the structure enlarged at G in the middle;

[0049] Fig.11 for Fig. 9 A schematic diagram after hiding the first seal, the second seal, the buffer pad, the first bolt and the second bolt;

[0050] Fig.12 for Fig.11 A schematic diagram of the structure enlarged at H in the middle;

[0051] Fig.13 for Fig.11 A schematic diagram after hiding the first rivet fixture and the second rivet fixture;

[0052] Fig.14 for Fig.13 A schematic diagram of the structure enlarged at M in the middle;

[0053] Fig.15 for Figure 1 A schematic diagram showing only the first seal and the second seal;

[0054] Fig.16 for Fig.15 A schematic diagram of the structure enlarged at N in the middle;

[0055] Fig.17 A flowchart of an embodiment of an assembly method of the present invention;

[0056] Fig.18 This is a sub-step flow chart of step S2 in an embodiment of the assembly method of the present invention;

[0057] Fig.19 This is a flow chart of sub-steps of step S21 in an embodiment of the assembly method of the present invention.

[0058] The meanings of the symbols in the accompanying drawings are:

[0059] Base plate 1a, frame 1, first threaded blind hole 11, third through hole 12, first rivet 13, fifth through hole 14, surrounding frame 15, cross beam 16, support plate 2, fourth through hole 21, buffer pad 22, bottom guard plate 3, first through hole 31, sixth through hole 32, protective layer 33, sealing assembly 4a, first sealing member 4, second through hole 41, first bolt 5, second rivet 6, second threaded blind hole 61, second bolt 7, second sealing member 71, anti-slip gasket 72. DETAILED DESCRIPTION

[0060] The present invention will be further described below in conjunction with the accompanying drawings.

[0061] Please refer to Figure 1-Figure 19 As shown, the assembly method of the frame-type battery box with good sealing performance in this embodiment specifically includes the following steps:

[0062] S1. Obtain the components of the frame-type battery box: including obtaining the frame 1, the bottom plate 1a, the sealing assembly 4a, the first bolt 5, the first protective structure, the first rivet 13, the second rivet 6, the second bolt 7, the second protective structure, the buffer pad 22, the insulating layer and the protective layer 33.

[0063] The bottom plate 1a includes a support plate 2 and a bottom guard plate 3. The bottom guard plate 3 has a peripheral portion that exceeds the periphery of the support plate 2 and is arranged opposite to the surrounding frame 15. The peripheral portion of the bottom guard plate 3 is provided with a plurality of first through holes 31. The support plate 2 has fourth through holes 21 that correspond one-to-one to the plurality of fifth through holes 14. The bottom guard plate 3 has a plurality of sixth through holes 32 that correspond one-to-one to some of the fourth through holes 21 at the position corresponding to the cross beam 16.

[0064] The frame 1 includes a surrounding frame 15 and a crossbeam 16 fixed in the surrounding frame 15. The surrounding frame 15 has first threaded blind holes 11 corresponding to the first through holes 31. The surrounding frame 15 also has third through holes 12 corresponding to the first through holes 31. Each third through hole 12 is riveted with a first rivet 13. The lower end of the surrounding frame 15 and the lower end of the crossbeam 16 also have a plurality of fifth through holes 14. In this embodiment, in order to reduce the weight of the frame 1, the frame 1 adopts a hollow frame structure.

[0065] The sealing assembly 4a includes a first sealing member 4 and a second sealing member 71. The first sealing member 4 can be configured as a frame-type sealing ring adapted to the plane size of the surrounding frame 15. The first sealing member 4 has second through holes 41 corresponding to the first through holes 31 one by one, and the second sealing member 71 has a mounting through hole. Both the first sealing member 4 and the second sealing member 71 can be made of rubber material, which has good sealing and aging resistance and can maintain a stable sealing effect during long-term use. At the same time, the elasticity of the rubber material can also effectively absorb and disperse the vibration and noise generated by the box when it is subjected to external impact, further improving the overall performance and comfort of the box.

[0066] The first rivet 13 has a first threaded blind hole 11 , and the second rivet 6 has a second threaded blind hole 61 .

[0067] S2. Assemble the frame-type battery box: arrange the first seal 4 at the periphery of the lower end of the frame 15, arrange the second seal 71 at the connection between the cross beam 16 and the bottom plate 1a, and press the bottom plate 1a onto the first seal 4, then fix the bottom plate 1a to the frame 1 and the cross beam 16, and fix the bottom plate 1a to the lower end of the cross beam 16, so as to seal the connection between the frame 1 and the bottom plate 1a and between the cross beam 16 and the bottom plate 1a.

[0068] In step S2, it specifically includes:

[0069] S21, fixing the support plate 2 to the surrounding frame 15 and the crossbeam 16.

[0070] In step S21, it specifically includes:

[0071] S211: placing the support plate 2 at the lower end of the surrounding frame 15 so that the plurality of fourth through holes 21 are aligned with the plurality of fifth through holes 14 one by one.

[0072] S212 : The support plate 2 and the surrounding frame 15 are welded by friction stir welding, and the second rivet 6 is inserted into the fourth through hole 21 and the fifth through hole 14 and riveted, so that the support plate 2 is fixed to the surrounding frame 15 and the crossbeam 16 .

[0073] It is worth mentioning that the friction stir welding connection method has the advantages of high strength, good sealing, and not easy to loosen, ensuring a stable connection between the support plate 2 and the frame 1. It is worth mentioning that in terms of sealing, the friction welding technology can achieve seamless connection, avoiding gaps or holes that may appear in traditional connection methods. This high degree of sealing is particularly important for application scenarios that need to prevent the penetration of liquids, gases or tiny particles, and can effectively ensure the safety and stability of the system.

[0074] During the welding operation, a step groove is provided on the inner side surface of the enclosure 15 near the lower end surface. The step groove penetrates the inner side surface of the enclosure 15 toward the inner cavity, and the step groove also penetrates the lower end surface of the enclosure 15 downward, so that the step groove is L-shaped. Before welding, the enclosure 15 is mounted upside down on the welding fixture, and then the support plate 2 is aligned and placed in the step groove. After placement, the upper end surface of the edge of the support plate 2 should be flush with the upper end surface of the enclosure 15. Then, the support plate 2 is fixed by the welding fixture to ensure that the support plate 2 and the enclosure 15 remain fixed, completing the preparation work before welding. During welding, the welding equipment applies axial pressure to the contact surface of the edge of the support plate 2 and the step groove through the welding head at the same time and rotates at high speed. During the high-speed rotation process, the metal on the contact surface generates high temperature due to friction. When the temperature reaches the melting point of the metal, the metals of the two begin to melt and mix together under the action of rotation. During this process, the welding equipment controls the welding head to move along the joint of the two for one circle. During this process, the metal in front of the moving track will be heated by friction until it melts and is stirred and mixed, and the metal behind the moving track will cool and solidify due to the end of friction, thus forming a seamless weld. The holes formed after the welding head at the end of the welding track is removed can be filled by repair welding to ensure the integrity and strength of the weld.

[0075] In this embodiment, since the frame 1 is a hollow structure, the threaded holes need to be formed by riveting the frame 1 with rivets. In other embodiments, the frame 1 may be a non-hollow structure, so that the corresponding threaded holes can be directly processed on the frame 1.

[0076] S22a: An insulating layer is formed on the side of the support plate 2 close to the bottom guard plate 3 and the side close to the frame 1 by coating or spraying.

[0077] It should be noted that step S22a is preferably performed between step S21 and step S22, so as to ensure the integrity of the insulating layer. Of course, in other embodiments, other step positions may be considered, such as before step S21.

[0078] The insulating layer can be formed by coating or spraying to ensure that it is evenly covered on the surface of the support plate 2 to form a good insulating barrier. In terms of material selection, high-performance insulating materials such as epoxy resin, polyimide, polyethylene, polytetrafluoroethylene or fluoroplastics can be considered. The selection of these insulating materials can be comprehensively considered based on the specific working environment, temperature range, mechanical strength requirements and cost of the box. By spraying these high-performance insulating materials, the insulation performance of the support plate 2 can be effectively improved, and the occurrence of electrical short circuits and electric shock accidents can be prevented, thereby improving the overall safety of the box.

[0079] S22: Arrange the first seal 4 on the periphery of the lower end of the frame 15, align the plurality of second through holes 41 with the plurality of first threaded blind holes 11 one by one, and at the same time arrange the second seal 71 at the position where the support plate 2 is connected to the bottom guard plate 3, and align the installation through holes of the plurality of second seals 71 with the plurality of sixth through holes 32 one by one.

[0080] S23a, arrange the buffer pad 22 on the inner side of the bottom guard plate 3.

[0081] The buffer pad 22 is arranged between the support plate 2 and the bottom guard plate 3 to effectively absorb and disperse vibration energy and protect the battery pack from external impact. The buffer pad 22 can be made of flexible materials such as rubber material or polyurethane foam, which not only have good shock absorption performance, but also can maintain a stable shape and performance during long-term use, and is not easy to age or deform.

[0082] S23b, arrange the protective layer 33 on the side of the bottom guard plate 3 away from the frame 1.

[0083] Providing the protective layer 33 not only enhances the surface strength of the bottom guard plate 3 and effectively resists external friction and wear, but also effectively isolates the direct contact between corrosive substances and the bottom guard plate substrate through the chemical stability and dense structure of the protective layer 33, thereby greatly reducing the risk of corrosion.

[0084] It should be noted that step S23a and step S23b may be performed in any order.

[0085] S23: Press the bottom guard plate 3 onto the first sealing member 4 and the second sealing member 71 so that the plurality of first through holes 31 are aligned with the plurality of second through holes 41 one by one.

[0086] S24: Assemble the first bolt 5 onto the first protective structure, then pass the first bolt 5 through the first through hole 31 and the second through hole 41 in sequence and threadedly fix them to the first threaded blind hole 11 of the first rivet 13, assemble the second bolt 7 onto the second protective structure, then pass the second bolt 7 through the sixth through hole 32 and threadedly fix them to the second threaded blind hole 61.

[0087] In this embodiment, the first protective structure and the second protective structure are both anti-skid pads 72 arranged between the bolt head and the corresponding component. By setting the anti-skid pads, when the box is subjected to vibration or external force impact, the bolts can be effectively prevented from loosening and causing connection failure, thereby ensuring the stability and sealing of the connection between the components, avoiding the increase of structural gaps caused by the loosening of the bolts, and then preventing external impurities such as water vapor and dust from invading the interior of the box and causing damage to key components such as batteries. In other embodiments, the protective structure can also use screw glue, which can fill the tiny gap between the bolt and the threaded hole, and form a high-strength bond after curing, further enhancing the reliability and stability of the bolt connection. Even in long-term and complex working conditions, such as frequent temperature changes, humidity fluctuations, and continuous vibration interference, the bolts can always be kept in a tight state, ensuring that the integrity and sealing of the overall structure of the battery box are not affected, and providing a solid guarantee for the safe and stable operation of the battery system.

[0088] In this embodiment, among the plurality of second threaded blind holes 61 corresponding to the positions of the cross beam 16, when one of the second threaded blind holes 61 is threadedly connected to the second bolt 7, the two second bolts 7 adjacent to it on the left and right are not connected to the second bolt 7. The fourth through holes 21 corresponding to the second threaded blind holes 61 connected to the second bolts 7 are part of the fourth through holes 21. Such a setting can reduce the overall weight by reducing unnecessary bolt connections without affecting the structural strength.

[0089] In this step, sealing is achieved through the first seal 4 and the second seal 71 while assembling the bottom guard plate 3 and the surrounding frame 15. Such a design can not only effectively prevent external impurities such as moisture and dust from entering the interior of the box, but also can isolate noise and vibration to a certain extent, providing a quieter and more stable operating environment for the battery pack.

[0090] After the frame-type battery box is assembled by the above assembly method, the support plate 2 and the bottom guard plate 3 are fixed to the lower end of the frame 1. This structural design can protect the support plate 2. When the lower end of the box is impacted, the bottom guard plate 3, as the first line of defense, can effectively absorb and disperse the impact force, thereby reducing damage to the support plate 2 and even the entire battery box.

[0091] In summary, the present invention discloses an assembly method for a frame-type battery box with good sealing performance, and the frame-type battery box assembled by this method has many beneficial effects. In terms of structural stability, the combination of stir friction welding and rivet fixings makes the connection of each component tight and reliable, and can withstand large external force impact and vibration, ensuring the structural integrity of the box during transportation and use. At the same time, the special frame design and reasonable bolt connection layout effectively reduce the overall weight while ensuring strength, improve energy utilization efficiency, and facilitate the application and promotion of battery boxes in new energy equipment. In terms of sealing and protection performance, the synergistic effect of sealing components, protective structures and friction welding forms a strict protection system, which not only prevents the intrusion of impurities such as water vapor and dust from the outside, but also effectively isolates noise and vibration, creating a stable and clean working environment for the battery pack, greatly extending the service life of the battery pack and improving its working performance. The setting of the protective layer further enhances the wear and corrosion resistance of the bottom guard plate, improves the durability and reliability of the box as a whole, can adapt to a variety of complex and harsh working environments, and reduces maintenance costs and frequencies.

[0092] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for assembling a frame-type battery box with good sealing performance, characterized in that: The following steps are involved: S1. Obtaining frame-type battery box parts: including obtaining a frame, a bottom plate and a sealing assembly; wherein the frame includes a surrounding frame, and the sealing assembly includes a first sealing member; S2. Assemble the frame-type battery box: arrange the first sealing member on the periphery of the lower end of the surrounding frame, press the bottom plate onto the first sealing member, and then fix the bottom plate to the frame to seal the connection between the frame and the bottom plate.

2. The assembly method according to claim 1, characterized in that: The frame further comprises a crossbeam; the sealing assembly further comprises a second sealing member; In step S2, it also includes: arranging a second sealing member at the connection between the cross beam and the bottom plate, and fixing the bottom plate to the lower end of the cross beam, thereby sealing the connection between the cross beam and the bottom plate.

3. The assembly method according to claim 2, characterized in that: The step S1 further includes obtaining a first bolt and a first protective structure; the bottom plate includes a support plate and a bottom guard plate, the bottom guard plate has a peripheral portion that exceeds the peripheral edge of the support plate and is arranged opposite to the surrounding frame, the peripheral portion of the bottom guard plate is provided with a plurality of first through holes, the surrounding frame has first threaded blind holes corresponding to the plurality of first through holes one by one, and the first sealing member has second through holes corresponding to the plurality of first through holes one by one; In step S2, it specifically includes: S21: fixing the support plate to the surrounding frame and the crossbeam; S22: arranging the first sealing member at the periphery of the lower end of the enclosure frame, aligning the plurality of the second through holes with the plurality of the first threaded blind holes one by one, and arranging the second sealing member at the position where the support plate is connected to the bottom guard plate; S23: Pressing the bottom guard plate onto the first sealing member and the second sealing member so that the first through holes are aligned one by one with the second through holes; S24: Assemble the first bolt onto the first protective structure, and then sequentially pass the first bolt through the first through hole and the second through hole and threadably fix the first bolt to the first threaded blind hole.

4. The assembly method according to claim 3, characterized in that: The step S1 further includes: obtaining a first rivet, the first rivet having a first threaded blind hole; the surrounding frame having third through holes corresponding to the first through holes, each of the third through holes being riveted with a first rivet; The step S24 specifically includes: assembling the first bolt onto the first protective structure, and then sequentially passing the first bolt through the first through hole and the second through hole and threading the first bolt into the first threaded blind hole of the first rivet.

5. The assembly method according to claim 3, characterized in that: The lower end of the surrounding frame and the lower end of the crossbeam both have a plurality of fifth through holes, and the support plate has fourth through holes corresponding to the plurality of the fifth through holes one by one; The step S1 further includes: obtaining a second rivet fixture; In step S21, it specifically includes: S211: placing the support plate at the lower end of the surrounding frame so that the plurality of fourth through holes are aligned one by one with the plurality of fifth through holes; S212: Weld the support plate to the surrounding frame by friction stir welding, and insert a second rivet into the fourth through hole and the fifth through hole and rivet them, so as to fix the support plate to the surrounding frame and the crossbeam.

6. The assembly method according to claim 5, characterized in that: The second rivet has a second threaded blind hole, and the bottom guard plate has a plurality of sixth through holes corresponding to some of the fourth through holes at positions corresponding to the crossbeams; The step S1 further includes: obtaining a second bolt and a second protective structure; In step S24, it also includes: assembling the second bolt onto the second protective structure, and then passing the second bolt through the sixth through hole and threading it with the second threaded blind hole.

7. The assembly method according to claim 6, characterized in that: The second sealing member has a mounting through hole; The S22 step is specifically as follows: arrange the first seal at the periphery of the lower end of the frame, align the plurality of the second through holes with the plurality of the first threaded blind holes one by one, and arrange the second seal at the position where the support plate is connected to the bottom guard plate, and align the installation through holes of the plurality of the second seals with the plurality of the sixth through holes one by one.

8. The assembly method according to claim 3, characterized in that: The step S1 further includes: obtaining an insulating layer; Before step S22, it also includes: S22a: Form an insulating layer on the side of the support plate close to the bottom guard plate and the side close to the frame by coating or spraying.

9. The assembly method according to claim 3, characterized in that: The step S1 further includes: obtaining a buffer pad and a protective layer; Before the step S23, the method further includes: S23a: arranging a buffer pad inside the bottom guard plate; S23b: Arrange a protective layer on the side of the bottom guard plate away from the frame.

10. A frame-type battery box with good sealing performance, which is assembled by any assembly method according to any one of claims 1 to 9.

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