Lower shell structure of battery pack, battery pack and operation machine

Abstract

The utility model relates to the technical field of power battery packs, and discloses a lower shell structure of a battery pack, the battery pack and an operation machine. The reinforcing frame comprises a frame body part and bent parts arranged at the two ends of the frame body part, the frame body part is fixedly connected with the bottom of the lower shell, and the bent parts are fixedly connected with the side part of the lower shell; and the mounting seat is fixedly arranged at the bending part, and the mounting seat is fixedly connected with the side part of the lower shell. According to the lower shell structure of the battery pack, the battery pack and the operation machine, the structural strength of the lower shell of the battery pack can be improved, and the safety is high.

Description

Technical Field

[0001] The utility model relates to the technical field of power battery packs, and in particular to a lower shell structure of a battery pack, a battery pack and an operating machine. Background Art

[0002] The battery pack shell is the outermost structure of the battery pack. The lower shell of the battery pack is used to install battery modules, electrical components, upper shell and other parts. The lower shell is the main load-bearing and sealing structural part of the power battery pack. It is generally installed on the lower body or chassis of special vehicles such as new energy vehicles and automobile cranes. Its main function is to form a closed and controllable space, which provides load-bearing and protection functions for various components inside the battery pack.

[0003] The battery pack shells used in new energy buses and truck cranes are commonly made of sheet metal, which are connected to the vehicle body at the lugs with bolts, and the lugs and the lower shell skin are welded. When the vehicle is driving or collides, the vibration load or impact load is transmitted through the lugs. Limited by the space of the vehicle, the design volume of the lugs is limited, and the welding area with the skin is very small, resulting in greater stress at the junction of the shell skin and the lugs. Under the impact load and alternating load, the battery pack shell is unevenly stressed, and it is easy to rupture the shell and fail the structure. In severe cases, the battery pack may catch fire or explode, causing harm to personnel. Utility Model Content

[0004] Therefore, the technical problem to be solved by the utility model is to overcome the defects in the prior art that the connection area between the hanging ear and the shell skin is small, the battery shell is unevenly stressed when impacted, structural failure is easy to occur, and the safety is low, and a lower shell structure of a battery pack, a battery pack and an operating machine are provided.

[0005] In the first aspect, the utility model provides a lower shell structure of a battery pack, which lower shell structure includes: a lower shell; a reinforcing frame, including a frame body and a bending portion arranged at both ends of the frame body, the frame body is fixedly connected to the bottom of the lower shell, and the bending portion is fixedly connected to the side of the lower shell; a mounting seat, fixedly arranged at the bending portion, and the mounting seat is fixedly connected to the side of the lower shell.

[0006] Optionally, the reinforcement frame includes a transverse beam and a longitudinal beam, the transverse beam and the longitudinal beam are cross-arranged, and bending portions are formed at both ends of the longitudinal beam.

[0007] Optionally, the frame body is provided with a first flange structure, which is fixedly connected to the bottom surface of the lower shell; the bending portion is provided with a second flange structure, which is fixedly connected to the side surface of the lower shell.

[0008] Optionally, the bent portion is embedded in a side of the mounting seat facing the lower shell, and the bent portion is welded to the mounting seat; the mounting seat is provided with a third flange structure, and the third flange structure is welded to the side of the lower shell.

[0009] Optionally, a first through hole is provided on the top of the mounting seat, and a second through hole is provided on the side of the mounting seat.

[0010] Optionally, the mounting seat includes an inner plate and an outer plate, the inner plate is arranged inside the outer plate and welded to the outer plate, and the inner plate and the outer plate jointly form a first through hole and a second through hole.

[0011] Optionally, the mounting seat further includes a sleeve, which is welded between the inner plate and the outer plate, and an inner cavity of the sleeve is arranged opposite to the first through hole.

[0012] Optionally, the outer side plate includes a first top plate and two first side plates, the two first side plates are connected to two sides of the first top plate, and the third flange structure is arranged on the first side plates.

[0013] In a second aspect, the utility model further provides a battery pack, comprising: the lower shell structure as described above.

[0014] In a third aspect, the utility model also provides a working machine, comprising the battery pack as described above.

[0015] By utilizing the technical solution of the utility model, the lower shell is fixed to the operating machine through the mounting seat, and the load on the operating machine will be transferred to the mounting seat. Since the mounting seat, the bending portion, and the frame portion form an integral structure, the load on the mounting seat can be transferred through the reinforcing frame, thereby improving the uniformity of the force on the lower shell, avoiding excessive stress at the connection between the lower shell and the mounting seat, and causing local structural rupture and failure, thereby improving the safety of the battery pack. In addition, the frame portion of the reinforcing frame is fixedly connected to the bottom of the lower shell, and the provision of the reinforcing frame can strengthen the structural strength and rigidity of the lower shell, so that the lower shell can withstand greater impact force and alternating stress, thereby improving the mechanical safety performance of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a schematic structural diagram of a lower shell structure of an embodiment of the utility model;

[0018] Figure 2 It is a partial structural schematic diagram of a lower shell structure of an embodiment of the utility model;

[0019] Figure 3 An exploded view of a lower shell structure according to an embodiment of the utility model;

[0020] Figure 4 This is a structural schematic diagram of a reinforcing frame and a mounting seat in a lower shell structure of an embodiment of the utility model;

[0021] Figure 5 for Figure 4 A partial enlarged view of the middle A;

[0022] Figure 6 This is a schematic diagram of the structure of a mounting seat in a lower shell structure of an embodiment of the utility model;

[0023] Figure 7 It is an exploded view of a mounting seat in a lower shell structure according to an embodiment of the utility model.

[0024] Description of reference numerals:

[0025] 1. Lower shell; 11. Outer shell; 12. Fixed frame; 2. Reinforcement frame; 2a. Frame body; 2b. Bending portion; 21. Crossbeam; 22. Longitudinal beam; 23. First flange structure; 24. Second flange structure; 3. Mounting seat; 31. Third flange structure; 32. First through hole; 33. Second through hole; 34. Outer plate; 341. First top plate; 342. First side plate; 35. Inner plate; 351. Second top plate; 352. Second side plate; 36. Sleeve. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0027] The battery pack shell of new energy buses, truck cranes, etc. in related technologies usually adopts a sheet metal structure, and the battery pack shell is connected to the vehicle body bolts through a lug. The battery pack shell includes a lower shell skin, and the lug and the lower shell skin are welded into shape. When the vehicle is running or collides, the vibration load or impact load is transmitted through the lug. Limited by the space of the whole vehicle, the design volume of the lug is limited, so the welding area between the lug and the lower shell skin is very small, which causes a large stress at the junction of the lower shell skin and the lug. Under the action of impact loads and alternating loads, the battery pack shell is unevenly stressed, and the shell is prone to rupture and structural failure. In severe cases, the battery pack may catch fire or explode, causing harm to personnel.

[0028] In some technical solutions, a concave-convex structure is provided at the bottom of the battery pack shell, and the concave-convex structure includes multiple bosses and multiple grooves arranged alternately. The arrangement of the bosses and grooves can enhance the strength and rigidity of the shell without increasing the thickness of the shell material. Removable hanging ears are provided on the left and right rear bosses of the battery pack shell. However, the production process of this technical solution is complicated and the cost is relatively high.

[0029] Based on this, the utility model provides a lower shell structure of a battery pack, a battery pack and an operating machine with high safety, simple production process and low cost.

[0030] Combine the following Figures 1 to 7 , describing an embodiment of the utility model.

[0031] According to an embodiment of the present utility model, on the one hand, a lower shell structure of a battery pack is provided, such as Figure 1-3 As shown, the lower shell structure includes a lower shell 1, a reinforcing frame 2 and a mounting seat 3. Among them, a mounting cavity is formed in the lower shell 1 for mounting the battery module. The reinforcing frame 2 includes a frame body 2a and a bending portion 2b provided at both ends of the frame body 2a, the frame body 2a is fixedly connected to the bottom of the lower shell 1, and the bending portion 2b is fixedly connected to the side of the lower shell 1. The mounting seat 3 is fixedly arranged at the bending portion 2b, and the mounting seat 3 is fixedly connected to the side of the lower shell 1.

[0032] It is understandable that in the present solution, the mounting seat 3 is fixedly arranged at the bending portion 2b, and the mounting seat 3 forms an integral structure with the bending portion 2b and the frame portion 2a. It should be noted that the mounting seat 3 in the present solution is suitable for being fastened to a partial structure of the operating machine (such as the body or chassis of the vehicle) so as to set the battery pack on the operating machine. Utilizing the technical solution of the present utility model, the lower shell 1 is fixed to the operating machine through the mounting seat 3, and the load on the operating machine will be transferred to the mounting seat 3. Since the mounting seat 3 forms an integral structure with the bending portion 2b and the frame portion 2a, the load on the mounting seat 3 can be transferred through the reinforcing frame 2, thereby improving the uniformity of the force on the lower shell 1, avoiding excessive stress at the connection between the lower shell 1 and the mounting seat 3, resulting in local structural rupture and failure, and thus improving the safety of the battery pack. In addition, the frame body 2a of the reinforcing frame 2 is fixedly connected to the bottom of the lower shell 1. The setting of the reinforcing frame 2 can strengthen the structural strength and rigidity of the lower shell 1, so that the lower shell 1 can withstand greater impact force and alternating stress, thereby improving the mechanical safety performance of the battery pack.

[0033] It should be noted that the operating machinery of the present invention includes but is not limited to new energy vehicles, truck cranes and other industrial equipment, aerospace equipment, power equipment, etc.

[0034] Further, in some embodiments, Figure 3 and 4 As shown, the reinforcement frame 2 includes a cross beam 21 and a longitudinal beam 22, the cross beam 21 and the longitudinal beam 22 are cross-arranged, and the bending portion 2b is formed at both ends of the longitudinal beam 22, and the frame body 2a is formed on the structure of the cross beam 21 and the longitudinal beam 22 except the bending portion 2b. The reinforcement frame 2 composed of the cross beam 21 and the longitudinal beam 22 has greater structural strength and rigidity and higher reliability.

[0035] Exemplarily, there are multiple cross beams 21 and longitudinal beams 22, multiple cross beams 21 are arranged at intervals along the first direction, multiple longitudinal beams 22 are arranged at intervals along the second direction, and the first direction and the second direction are perpendicular to each other. The multiple cross beams 21 and the multiple longitudinal beams 22 are arranged in a cross-shaped manner, and the overlaps of the cross beams 21 and the longitudinal beams 22 are welded into an integral structure. The first direction may be the length direction of the lower shell 1, and the second direction may be the width direction of the lower shell 1.

[0036] Exemplarily, the cross beam 21 and the longitudinal beam 22 are provided with a groove structure, and the two sides of the cross beam 21 and the longitudinal beam 22 are provided with a flange structure, and the flange structure is connected to the bottom and the side of the lower shell 1. Exemplarily, the cross section of the cross beam 21 and the longitudinal beam 22 can be constructed as a "J"-shaped flange structure, or, in some embodiments not shown in the figures, the groove structure on the cross beam 21 and the longitudinal beam 22 can be set to "W", "V", "U", "O" type, etc. The cross beam 21 and the longitudinal beam 22 set in this way can not only play a role in strengthening the structural strength of the lower shell, but also have a high degree of lightweight.

[0037] In some embodiments not shown in the figures, the cross beam 21 and the longitudinal beam 22 may also be constructed as a solid rod-shaped structure, and flange structures are provided on both sides of the rod-shaped structure. The present application does not specifically limit the structure of the cross beam 21 and the longitudinal beam 22, as long as the weight design requirements of the lower shell structure can be met.

[0038] Further, such as Figure 5 As shown, the flange structure includes a first flange structure 23 and a second flange structure 24. The frame body 2a is provided with the first flange structure 23, and the first flange structure 23 is fixedly connected to the bottom surface of the lower shell 1. The bending portion 2b is provided with the second flange structure 24, and the second flange structure 24 is fixedly connected to the side of the lower shell 1. The provision of the first flange structure 23 and the second flange structure 24 can increase the connection area between the reinforcing frame 2 and the lower shell 1, so that the force area for transferring the load between the reinforcing frame 2 and the lower shell 1 is increased, and the lower shell 1 is prevented from being broken by force.

[0039] Exemplarily, the first flange structure 23 is welded to the bottom surface of the lower shell 1, and the second flange structure 24 is welded to the side surface of the lower shell 1. Preferably, the first flange structure 23 and the bottom surface of the lower shell 1, and the second flange structure 24 and the side surface of the lower shell 1 can be connected by spot welding, which is simple to operate and highly efficient.

[0040] Furthermore, the above-mentioned bending portion 2b is embedded in the side of the mounting seat 3 facing the lower shell 1, and the bending portion 2b is welded to the mounting seat 3, so that the mounting seat 3 and the reinforcing frame 2 form an integral structure. The mounting seat 3 is provided with a third flange structure 31, and the third flange structure 31 is welded to the side of the lower shell 1. The third flange structure 31 increases the connection area between the mounting seat 3 and the lower shell 1, so that the force bearing area for transferring load between the mounting seat 3 and the lower shell 1 is increased, and the structural safety of the lower shell 1 is further ensured.

[0041] Exemplarily, the interior of the mounting seat 3 is hollow, the bent portion 2b is embedded in the interior of the mounting seat 3, and the bent portion 2b is welded to the mounting seat 3. Exemplarily, both sides of the bent portion 2b are provided with a first flange structure 23, and the first flange structure 23 is welded to the inner side of the mounting seat 3. Preferably, the first flange structure 23 is located on the inner side of the third flange structure 31, and the first flange structure 23 and the third flange structure 31 are located on the same plane, so that both are connected to the side of the lower shell 1.

[0042] Furthermore, the mounting seats 3 are arranged in pairs, and the mounting seats 3 arranged in pairs are respectively arranged on the bending portions 2b at both ends of the reinforcing frame 2 to provide balanced support points for the lower shell 1. Among them, the mounting seats 3 can be arranged in one pair or multiple pairs. In the lower shell structure arranged in this way, the mounting seats 3 arranged in pairs can provide balanced support points for the battery pack in the lower shell 1, avoiding the battery pack from tilting and achieving better stability.

[0043] For example, Figure 4 As shown, the reinforcing frame 2 includes two cross beams 21 and three longitudinal beams 22 arranged crosswise, and the two ends of the three longitudinal beams 22 are formed with the above-mentioned bending portions 2b, that is, the reinforcing frame 2 has six bending portions 2b. Correspondingly, the above-mentioned mounting seats 3 arranged in pairs are correspondingly arranged in three pairs, that is, six mounting seats 3 are arranged. The six mounting seats 3 are respectively fixed on the six bending portions 2b. In the lower shell structure arranged in this way, a plurality of mounting seats 3 are formed into an integral structure through the reinforcing frame 2. When subjected to impact force, if the force at a certain mounting seat 3 is large, the force can be transmitted to other mounting seats 3 with smaller force through the reinforcing frame 2, so that the overall force of the lower shell structure is uniform.

[0044] The utility model does not specifically limit the number of mounting seats 3 and bending portions 2b, as long as they can serve the function of connecting the battery pack and the operating machine. Among them, the number of mounting seats 3 and bending portions 2b can be the same or different, as long as the mounting seats 3 can provide balanced support points. When there are multiple longitudinal beams 22, you can choose to set the bending portion 2b on some of the multiple longitudinal beams 22, or you can choose to set the bending portion 2b on all the multiple longitudinal beams 22. Accordingly, there are multiple mounting seats 3, and the number of mounting seats 3 can be less than the number of bending portions 2b, or it can be the same as the number of bending portions 2b.

[0045] Exemplarily, in some embodiments not shown in the figures, three longitudinal beams 22 are provided, and two ends of two longitudinal beams 22 located on both sides of the three longitudinal beams 22 are formed with bending portions 2b, and two pairs of mounting seats 3 are provided, and the two pairs of mounting seats 3 are respectively connected to the bending portions 2b of the two longitudinal beams 22 located on both sides.

[0046] It should be noted that the present invention does not impose any specific limitation on the number of the cross beams 21 and the longitudinal beams 22 , as long as they can transmit the bearing capacity and enhance the structural strength of the lower shell.

[0047] Further, such as Figure 5-7 As shown, a first through hole 32 is provided on the top of the mounting base 3, and a second through hole 33 is provided on the side of the mounting base 3. The first through hole 32 can be passed through by a bolt to achieve a fastening connection with the operating machine. The second through hole 33 can be used as a lifting hole to provide a lifting point for the lower shell structure, avoiding the need to set a lifting hole on the lower shell 1 or the upper shell of the battery pack shell, and further ensuring the structural strength of the battery pack shell.

[0048] Furthermore, the mounting base 3 includes an inner plate 35 and an outer plate 34, wherein the inner plate 35 is disposed inside the outer plate 34 and is welded to the outer plate 34, and the inner plate 35 and the outer plate 34 together form a first through hole 32 and a second through hole 33. With the double-layer plate structure of the inner plate 35 and the outer plate 34, the mounting base 3 has a higher structural strength.

[0049] Exemplarily, the outer side plate 34 includes a first top plate 341 and two first side plates 342, and the two first side plates 342 are connected to both sides of the first top plate 341. The inner side plate 35 includes a second top plate 351 and a second side plate 352, and the two second side plates 352 are connected to both sides of the two second top plates 351. In other words, the longitudinal cross-section of the outer side plate 34 and the inner side plate 35 is roughly constructed as a "∩"-shaped structure. Among them, the two second side plates 352 are respectively located on the inner sides of the two first side plates 342, and the two second side plates 352 are respectively fixedly connected to the two first side plates 342. Exemplarily, the second side plate 352 and the first side plate 342 are welded into an integrated structure, which can be specifically spot welding or welding.

[0050] Exemplarily, both the inner panel 35 and the outer panel 34 can be made of sheet metal materials, preferably cold-rolled thin plates. The first top panel 341 and the two first side panels 342 of the outer panel 34 can be integrally formed by a bending forming process. The second top panel 351 and the two second side panels 352 of the inner panel 35 can also be integrally formed by a bending forming process. The process is simple and the production cost is low.

[0051] For example, Figure 7 As shown, the third flange structure 31 is arranged on the first side plate 342, and the third flange structure 31 is arranged at an angle with the first side plate 342. Preferably, the third flange structure 31 is arranged at a 90° angle with the first side plate 342, and the two third flange structures 31 on the two first side plates 342 are approximately located on the same plane, so as to facilitate welding with the lower shell 1.

[0052] Further, such as Figure 6 and7 As shown, the mounting seat 3 further includes a sleeve 36, which is welded between the inner plate 35 and the outer plate 34, and the inner cavity of the sleeve 36 is arranged opposite to the first through hole 32. Exemplarily, the sleeve 36 can be obtained by seamless steel pipe or machining. The top of the sleeve 36 is welded to the first top plate 341, and the bottom of the sleeve 36 is welded to the second top plate 351, preferably by welding, so that the sleeve 36, the inner plate 35, and the outer plate 34 form an integral structure, and are fixedly connected to the lower shell 1 through the third flange structure 31.

[0053] The mounting seat 3 is configured in this way, and adopts a double-layer side plate (outer plate 34 and inner plate 35) plus a sleeve 36. When the mounting seat 3 is fastened to the working machine through the first through hole 32 by bolts, the sleeve 36 can bear the pre-tightening force of fasteners such as bolts, reduce the stress amplitude of the outer plate 34 and the inner plate 35, and improve the reliability of the mounting seat 3. At the same time, a cavity structure is formed between the outer plate 34, the inner wall and the supporting sleeve 36, which optimizes the load transfer path and further improves the structural strength of the mounting seat 3.

[0054] Further, such as Figure 3 As shown, the lower shell 1 includes an outer shell 11 and a fixing frame 12. The outer shell 11 is the outer skin structure of the lower shell 1, and the outer shell 11 is formed with the above-mentioned mounting cavity for mounting the battery module. The fixing frame 12 is arranged in the mounting cavity and is located at the bottom of the mounting cavity. The fixing frame 12 is used to mount and fix the battery module. The present application does not specifically limit the structure of the outer shell 11 and the fixing frame 12. The specific structure of the outer shell 11 and the fixing frame 12 can be adjusted according to the distribution and structural adaptability of the battery module, as long as the function of carrying the battery module can be achieved.

[0055] It can be understood that the frame body 2a of the reinforcing frame 2 is fixedly connected to the bottom of the shell 11, the bent portion 2b is fixedly connected to the side of the shell 11, and the mounting seat 3 is fixedly connected to the side of the shell 11. In the lower shell structure configured in this way, when subjected to external impact, the mounting seat 3 and the reinforcing frame 2 are an integrated structure, and under the load transfer effect of the mounting seat 3 and the reinforcing frame 2, the shell 11 is subjected to a uniform load, and it is not easy to cause structural rupture or failure; and the structural strength of the reinforcing frame 2 is stronger than that of the shell 11, and the reinforcing frame 2 shares the load on the shell 11, and never avoids the shell 11 from being subjected to excessive load.

[0056] According to an embodiment of the utility model, on the other hand, a battery pack is provided, comprising the lower shell structure as described in the above embodiment. The battery pack of the present invention comprises the lower shell structure of the above embodiment, and has the same technical effect as the lower shell structure of the present invention, which will not be described in detail here.

[0057] The battery pack of the present invention also includes an upper shell structure and a battery module. The upper shell structure is connected to the lower shell structure, and the lower shell structure covers the opening of the installation cavity of the lower shell 1. The upper shell structure and the lower shell structure together form a closed installation space, and the above-mentioned battery module is arranged in the installation space.

[0058] According to an embodiment of the utility model, on the other hand, a working machine is provided, including the lower shell structure as described above, or including the battery pack as described above. The working machine of the present invention includes the lower shell structure or battery pack of the above embodiment, and has the same technical effect as the lower shell structure or battery pack of the present invention, which will not be described in detail here.

[0059] In the lower shell structure, battery pack and operating machinery of the present invention, the mounting base 3 and the reinforcing frame 2 form an integral structure. The connection area between the mounting base 3 and the reinforcing frame 2 and the lower shell 1 is large, the force-bearing area of ​​load transfer is increased, the overall strength of the lower shell structure of the battery pack is optimized, and it can withstand greater impact force and alternating stress, thereby improving the mechanical safety performance of the battery pack.

[0060] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A lower shell structure of a battery pack, characterized in that: The lower shell structure comprises: Lower housing (1); The reinforcing frame (2) comprises a frame body (2a) and bent portions (2b) provided at both ends of the frame body (2a), wherein the frame body (2a) is fixedly connected to the bottom of the lower shell (1), and the bent portions (2b) are fixedly connected to the side of the lower shell (1); The mounting seat (3) is fixedly arranged at the bending portion (2b), and the mounting seat (3) is fixedly connected to the side of the lower shell (1).

2. The lower shell structure of the battery pack according to claim 1, characterized in that: The reinforcing frame (2) comprises a cross beam (21) and a longitudinal beam (22), wherein the cross beam (21) and the longitudinal beam (22) are arranged crosswise, and the bent portion (2b) is formed at both ends of the longitudinal beam (22).

3. The lower shell structure of the battery pack according to claim 1 or 2, characterized in that: The frame portion (2a) is provided with a first flange structure (23), and the first flange structure (23) is fixedly connected to the bottom surface of the lower shell (1); the bending portion (2b) is provided with a second flange structure (24), and the second flange structure (24) is fixedly connected to the side surface of the lower shell (1).

4. The lower shell structure of the battery pack according to claim 3, characterized in that: The bent portion (2b) is embedded in a side of the mounting seat (3) facing the lower shell (1), and the bent portion (2b) is welded to the mounting seat (3); The mounting seat (3) is provided with a third flange structure (31), and the third flange structure (31) is welded to the side surface of the lower shell (1).

5. The lower shell structure of the battery pack according to claim 4, characterized in that: The top of the mounting seat (3) is provided with a first through hole (32), and the side of the mounting seat (3) is provided with a second through hole (33).

6. The lower shell structure of the battery pack according to claim 5, characterized in that: The mounting seat (3) comprises an inner plate (35) and an outer plate (34); the inner plate (35) is arranged inside the outer plate (34) and welded to the outer plate (34); the inner plate and the outer plate (34) together form the first through hole (32) and the second through hole (33).

7. The lower shell structure of the battery pack according to claim 6, characterized in that: The mounting seat (3) further comprises a sleeve (36), wherein the sleeve (36) is welded between the inner plate (35) and the outer plate (34), and an inner cavity of the sleeve (36) is arranged opposite to the first through hole (32).

8. The lower shell structure of the battery pack according to claim 6, characterized in that: The outer side plate (34) comprises a first top plate (341) and two first side plates (342), wherein the two first side plates (342) are connected to two sides of the first top plate (341), and the third flange structure (31) is arranged on the first side plates (342).

9. A battery pack, characterized in that: include: The lower shell structure according to any one of claims 1 to 8.

10. A working machine, characterized in that: Comprising the battery pack as claimed in claim 9.

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