Battery pack

Abstract

A battery pack. The battery pack comprises a case (1) and a BDU (2); a battery module and expansion beams (11) are provided in the case (1); the battery module comprises single cells (3) arranged in a first direction; in the first direction, one expansion beam (11) is attached to each of two ends of the battery module; the expansion beams (11) generate elastic deformation in the first direction at least when the single cells (3) expand; the BDU (2) is located between the expansion beams (11) and the case (1), and comprises a fixing frame (21), a BDU body (22), and a fastener (23); the fixing frame (21) is fixedly connected to the expansion beams (11); a slide portion is provided on the BDU body (22); and the fastener (23) is fixedly connected to the fixing frame (21) and is slidably provided on the slide portion in the first direction.

Description

Battery pack

[0001] This application claims priority to Chinese patent applications No. 202422394942.4 and 202411379018.7, filed on September 30, 2024, with the Chinese Patent Office, the contents of which are incorporated herein by reference in their entirety.

[0002] TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, for example to a battery pack.

[0004] BACKGROUND

[0005] Battery disconnect unit (BDU) is an important component designed inside the battery pack, often used as a distribution box. When the battery pack system reports an error, the BDU can cut off the internal current of the power battery to ensure system safety.

[0006] TECHNICAL PROBLEM

[0007] In the battery pack design in the related art, the fixing bracket connected to the BDU base is usually welded on the expansion beam in the battery pack shell. When the battery pack expands, the expansion beam will bend and deform, and the fixing bracket and the BDU will move together. The BDU is squeezed by the expansion beam and the battery pack shell at the same time, causing the BDU shell to deform, affecting the service life.

[0008] Currently, the related art often thickens the expansion beam to increase the strength of the expansion beam, or adds a cross beam (i.e. a beam perpendicular to the extension direction of the expansion beam) to reduce the expansion force generated by the battery pack expansion. However, both methods will occupy the space of other components in the battery pack shell, making the battery pack design layout process complex.

[0009] TECHNICAL SOLUTION

[0010] The present application provides a battery pack to solve the technical defects in the related art of thickening the expansion beam in the battery pack shell or adding a cross beam, which occupies the space of other components in the battery pack shell, affecting the design and production of the battery pack.

[0011] The present application provides a battery pack having a first direction and a second direction, the first direction being perpendicular to the second direction, the battery pack comprising:

[0012] a shell, the shell having a receiving cavity, the receiving cavity having a battery pack and an expansion beam, the battery pack comprising a plurality of single cells, the plurality of single cells being arranged in sequence along the first direction, and each end of the battery pack being provided with an expansion beam along the first direction, the expansion beam being configured to elastically deform along the first direction at least when the single cells expand;

[0013] The BDU unit is arranged in the accommodating cavity and located between the expansion beam and the shell. The BDU unit comprises a fixing frame, a BDU body and a fastener. The fixing frame is fixedly connected to the expansion beam. The BDU body is provided with a sliding part. The fastener is fixedly connected to the fixing frame and is arranged on the sliding part in a sliding manner along the first direction.

[0014] Advantages

[0015] By arranging the sliding part on the BDU body, when the expansion beam is elastically deformed, the expansion beam will slide on the sliding part with the fastener, avoiding the movement of the BDU body, so that the position of the BDU body remains unchanged. That is, the sliding part absorbs the displacement amount of the fixing frame when the expansion beam is elastically deformed, thereby avoiding the situation that the BDU body is squeezed and deformed due to the movement of the BDU body, improving the use safety of the BDU body, and avoiding the additional occupation of the installation space of other parts in the battery pack shell, preventing the overall design and manufacture of the battery pack from becoming complex.

[0016] BRIEF DESCRIPTION OF DRAWINGS

[0017] FIG. 1 is a schematic view of the internal structure of a battery pack according to some embodiments of the present application;

[0018] FIG. 2 is an enlarged view of a portion of FIG. 1;

[0019] FIG. 3 is a sectional view taken along line B-B of FIG. 2;

[0020] FIG. 4 is an enlarged view of a portion of FIG. 3;

[0021] FIG. 5 is a schematic view of the structure of a BDU unit according to some embodiments of the present application;

[0022] FIG. 6 is an exploded view of the structure of a BDU unit according to some embodiments of the present application;

[0023] FIG. 7 is an enlarged view of a portion of FIG. 6;

[0024] FIG. 8 is an enlarged view of a portion of FIG. 6;

[0025] FIG. 9 is a schematic view of a first relief chamfer and a second relief chamfer according to some embodiments of the present application.

[0026] In the drawings:

[0027] 1, shell; 2, BDU unit; 3, single cell;

[0028] 11, expansion beam; 12, cross beam;

[0029] 21, fixing frame;

[0030] 22, BDU body; 2201, mounting waist hole; 2202, mounting through hole; 221, upper cover; 2211, upper cover body; 2212, clamping structure; 22121, clamping groove; 22122, clamping plate; 22123, rib; 22124, first chamfer; 2213, avoidance gap; 2214, pressing groove; 2215, limiting plate; 222, base; 2221, boss; 22211, second chamfer; 2222, guide structure; 223, electrical assembly;

[0031] 23, fastener; 231, locking bolt; 2311, third flange; 232, rivet nut; 2321, first flange; 233, first screw sleeve; 2331, screw sleeve body; 2332, second flange;

[0032] 24, locking piece;

[0033] 31, first avoidance chamfer; 32, second avoidance chamfer.

[0034] Embodiments of the present application

[0035] The technical solutions provided by the present application will be described below in conjunction with the drawings and specific embodiments.

[0036] In the drawings of the embodiments of the present application, the bidirectional arrow marked X represents the first direction, the bidirectional arrow marked Y represents the second direction, and the bidirectional arrow marked Z represents the third direction. In the present embodiment, the first direction X corresponds to the thickness direction of the single cell 3, and for a square single cell 3, the directions corresponding to the two large faces are the thickness direction, i.e., the first direction X; the second direction Y corresponds to the height direction of the single cell 3; and the third direction Z corresponds to the length direction of the single cell 3. In the present embodiment, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other in pairs.

[0037] The present embodiment provides a battery pack, which comprises a shell 1 and an upper cover 221 matched with the shell 1, and the shell 1 is provided with a containing cavity, and the upper cover 221 is buckled on the shell 1 to seal the containing cavity. As shown in FIG. 1, the containing cavity is provided with a battery pack and an expansion beam 11, the battery pack comprises a plurality of single cells 3 arranged in sequence along the first direction, and along the first direction, one expansion beam 11 is attached to each of the two ends of the battery pack, the length of the expansion beam 11 extends along the third direction, and the two ends of the expansion beam 11 are fixed on the inner side wall of the shell 1. In the present embodiment, the battery pack abandons the traditional module structure, and a plurality of single cells 3 are arranged in groups to form a battery pack, and the battery pack is directly arranged in the containing cavity and is shaped by the expansion beams 11 attached to the two ends to avoid shaking of the battery pack, so that the battery pack can be directly grouped, the assembly process of the battery pack is simplified, the number of parts used is reduced, the volume and production cost of the battery pack are reduced, and the energy density of the battery pack is improved.

[0038] In addition, during the charging and discharging of the single battery cell 3, the single battery cell 3 expands in the thickness direction, so that the overall size of the battery pack expands to both sides in the first direction. The expansion beam 11 can elastically deform in the first direction after being pressed to provide space for the expansion of the single battery cell 3.

[0039] It can be understood that more expansion beams 11 can be arranged in the first direction in the battery pack, so that more assembly spaces for assembling the battery pack can be defined by arranging more expansion beams 11, thereby enabling more battery packs to be assembled.

[0040] Referring to FIG. 2, the battery pack further includes a BDU unit 2 arranged in the accommodating cavity. The BDU unit 2 is located between the shell 1 and one of the expansion beams 11 at the edge. The BDU unit 2 includes a fixing frame 21, a BDU body 22, and a fastener 23. The fixing frame 21 is fixedly connected to the expansion beam 11, and the BDU body 22 is fixedly installed on the fixing frame 21 by the fastener 23 to complete the installation of the BDU unit 2 in the battery pack. When the single battery cell 3 expands, the expansion beam 11 elastically deforms in the first direction. At this time, the expansion beam 11 moves forward with the entire BDU unit 2, causing the BDU body 22 to be pressed by the expansion beam 11 and the shell 1 and deformed, thereby affecting the service life. However, the thickening of the expansion beam 11 or the addition of the cross beam 12 (a beam perpendicular to the length extension direction of the expansion beam 11) in the related art still cannot eliminate the phenomenon of elastic deformation of the expansion beam 11 being pressed, and the BDU unit 2 still has the risk of being damaged by being pressed.

[0041] The BDU body 22 provided in the embodiment is provided with a sliding portion, and the fastener 23 is fixedly connected to the fixing frame 21 and is slidably arranged on the sliding portion in the first direction. When the expansion beam 11 expands and deforms, the fastener 23 can slide on the sliding portion to absorb the displacement of the fixing frame when the expansion beam deforms.

[0042] In one of the embodiments of the present embodiment, the BDU body 22 is provided with a mounting waist hole 2201 penetrating in the second direction, the length direction of the mounting waist hole 2201 is parallel to the first direction, the fastener 23 is arranged in the mounting waist hole 2201 and fixedly connected to the fixing frame 21, and the fastener 23 is slidably arranged in the mounting waist hole 2201. Through the arrangement, when the expansion beam 11 is elastically deformed, the expansion beam 11 will slide with the fastener 23 in the mounting waist hole 2201, avoiding driving the BDU body 22 to move along the first direction. That is, the mounting waist hole 2201 absorbs the displacement amount of the fixing frame 21 when the expansion beam 11 is deformed, thereby avoiding the situation that the BDU body 22 is squeezed and deformed due to movement, improving the safety of the BDU body 22, and avoiding occupying the installation space of other parts in the battery pack shell 1, preventing the overall design and manufacture of the battery pack from becoming complex.

[0043] In addition, the mounting waist hole 2201 can absorb the manufacturing tolerance of the fixing frame 21, ensuring that the fastener 23 can be accurately fixed on the fixing frame 21 through the mounting waist hole 2201, thereby improving the assembly of the BDU body 22 and the manufacturability of the fixing frame 21.

[0044] In the present embodiment, referring to FIG. 4, the fastener 23 includes a locking bolt 231 and a pull rivet nut 232, the pull rivet nut 232 is arranged on the fixing frame 21, the locking bolt 231 is arranged in the mounting waist hole 2201 and connected with the pull rivet nut 232, and the pull rivet nut 232 includes a first flange 2321 at the end of the pull rivet nut 232, and the first flange 2321 is clamped between the BDU body 22 and the fixing frame 21. Through the arrangement of the locking bolt 231 and the pull rivet nut 232, the BDU body 22 can be fixed and mounted on the fixing frame 21 in a threaded connection manner, not only saving the operation of tapping internal threads on the fixing frame 21, simplifying the fixing method, but also facilitating the fixation of the BDU body 22 in a narrow space.

[0045] In addition, by clamping the first flange 2321 between the BDU body 22 and the fixing frame 21, on the one hand, the surface of the BDU body 22 can be protected, avoiding the BDU body 22 being squeezed and deformed by the fixing frame 21 when the BDU body 22 and the fixing frame 21 are in direct contact; on the other hand, the first flange 2321 can replace the fixing frame 21 to contact the BDU body 22, thereby reducing the contact area of the fixing frame 21 and the BDU body 22, and further facilitating the movement of the fixing frame 21 and reducing the obstruction of the BDU body 22.

[0046] Continuing to refer to FIG. 4, the fastener 23 further comprises a first sleeve 233, which comprises a sleeve body 2331 embedded in the mounting waist hole 2201 and a second flange 2332 arranged at an end of the sleeve body 2331 and abutting against the BDU body 22. In addition, the locking bolt 231 comprises a stud body and a third flange 2311, the stud body is arranged through the sleeve body 2331 and connected with the pull nut 232, and the third flange 2311 is arranged at an outer periphery of the stud body and abuts against the second flange 2332. It can be understood that the BDU body 22 is usually a plastic part to achieve electrical insulation. By arranging the first sleeve 233 on the BDU body 22, the pressure of the locking bolt 231 is not directly applied to the BDU body 22, but is applied to the first sleeve 233, so that the possibility of deformation or even damage of the BDU body 22 caused by being crushed by the locking bolt 231 can be avoided.

[0047] The end of the sleeve body 2331 away from the second flange 2332 is flush with the opening of the mounting waist hole 2201 and is connected to the first flange 2321 to support the first sleeve 233 through the pull nut 232, so that the pressure of the second flange 2332 on the BDU body 22 is eliminated, and the second flange 2332 abuts against the BDU body 22, so that when the battery pack expands and the fixed frame 21 moves forward, the locking bolt 231 and the first sleeve 233 can move freely.

[0048] In the embodiment, as shown in FIG. 9, a first chamfer 31 is arranged at the connection between the sleeve body 2331 and the second flange 2332, and a second chamfer 32 is arranged at the opening of the mounting waist hole 2201 facing the second flange 2332, and the first chamfer 31 is arranged relative to the second chamfer 32 to have a certain assembly gap between the first sleeve 233 and the mounting waist hole 2201, increase the freedom of movement of the first sleeve 233 in the second direction Y, and facilitate the assembly of the first sleeve 233. It can be understood that the first chamfer 31 and the second chamfer 32 can be round chamfers or bevel chamfers, and the present application is not limited thereto.

[0049] Optionally, referring to FIG. 1, a cross beam 12 is arranged in the shell 1, the length extension direction of the cross beam 12 is parallel to the first direction X, and the cross beam 12 is fixedly connected with a expansion beam 11 at both ends in the first direction, so as to effectively reduce the elastic deformation amount of the expansion beam 11, thereby helping to reduce the movement distance of the fixed frame 21, the locking bolt 231 and the first sleeve 233, and effectively avoiding the risk of the BDU body 22 being crushed and deformed due to the movement distance of the first sleeve 233 exceeding the length of the mounting waist hole 2201.

[0050] In the embodiment, three expansion beams 11 are arranged in the first direction in the shell 1, and two cross beams 12 are arranged in the third direction between the adjacent two expansion beams 11. The arrangement of the cross beams 12 can reduce the elastic deformation amount of the expansion beam 11, so that the elastic deformation amount of the expansion beam 11 is controlled within a reasonable range. The opposite sides of the cross beam 12 can be provided with a battery pack. For example, in the embodiment, one battery pack is arranged between the two cross beams 12, and one battery pack is arranged between the cross beam 12 and the shell 1. In this way, six battery packs can be placed in the shell 1 to meet the energy density use requirement under actual working conditions.

[0051] Optionally, in the embodiment, as shown in FIG. 5, two mounting waist holes 2201 are arranged on the BDU body 22 in the third direction, and a plurality of fixing frames 21 are fixedly arranged on the expansion beam 11. Each mounting waist hole 2201 is fixedly connected with a fixing frame 21 through a fastener 23, so that the mounting stability of the BDU body 22 in the battery pack can be improved through the plurality of fasteners 23. At the same time, since the expansion beam 11 is provided with a plurality of battery packs in the third direction, the expansion degrees of these battery packs are not completely the same due to different factors such as heat dissipation conditions, environment, material batch, etc. during actual use. The positions of the two mounting waist holes 2201 in the embodiment are designed at the two positions which are prone to expansion deformation on the expansion beam 11, so that when the expansion beam 11 expands and deforms at different positions, there are corresponding mounting waist holes 2201 to absorb the displacement amount generated by the expansion beam 11, the fixing frame 21 and the fastener 23, thereby avoiding the deformation of the BDU body 22 caused by the extrusion of the expansion beam 11 and the shell 1.

[0052] In the embodiment, one of the mounting waist holes 2201 is located at one end of the side of the BDU body 22 adjacent to the expansion beam 11, and the other mounting waist hole 2201 is located at the middle position of the side of the BDU body 22 adjacent to the expansion beam 11. It can be understood that the number and position of the mounting waist hole 2201 are not limited in the embodiment, as long as the BDU body 22 can be prevented from being extruded and deformed when the expansion beam 11 expands and deforms, which is within the protection scope of the application.

[0053] Optionally, the BDU body 22 provided in the embodiment is further provided with three mounting through holes 2202 on the outer circumferential surface. One of the three mounting through holes 2202 is located at the other end of the side of the BDU body 22 adjacent to the expansion beam 11 and is fixedly connected with the shell 1 through a locking piece 24. The other two mounting through holes 2202 are located on the side of the BDU body 22 away from the expansion beam 11 and are fixedly connected with the shell 1 through two locking pieces 24. In this way, the mounting stability of the BDU unit 2 in the battery pack can be improved by increasing the fixing points on the BDU body 22.

[0054] The locking member 24 comprises a locking bolt and a second threaded sleeve, the structure of the second threaded sleeve is the same as that of the first threaded sleeve 233, which will not be described herein again, the second threaded sleeve is embedded in the mounting through hole 2202, and the locking bolt is threadedly connected to the shell 1 through the second threaded sleeve. It should be noted that in the embodiment, the second threaded sleeve is fixed in the mounting through hole 2202 by welding or bonding, so that the second threaded sleeve is integrated with the BDU body 22. Since the locking bolt does not need to move in the first direction X in the mounting through hole 2202, the second threaded sleeve and the mounting through hole 2202 do not need to be designed in a movable connection manner, and the second threaded sleeve is fixed in the mounting through hole 2202, which can reduce the installation failure caused by loosening of the locking member 24, thereby ensuring the stability of use of the BDU body 22.

[0055] Optionally, in order to improve the installation efficiency of the battery pack, the BDU body 22 is improved in the embodiment.

[0056] Referring to FIG. 6, the BDU body 22 comprises a base 222 and an upper cover 221, wherein the base 222 is provided with an electrical assembly 223, the base 222 is provided with a mounting waist hole 2201, and the end surface of the base 222 is provided with a boss 2221 outwardly protruding in the third direction Z. In addition, the upper cover 221 comprises an upper cover body 2211 and a clamping structure 2212, the upper cover body 2211 is provided with the clamping structure 2212, the clamping structure 2212 has a clamping groove 22121, and when the upper cover body 2211 is buckled on the base 222, the boss 2221 is clamped in the clamping groove 22121. In this way, after the electrical assembly 223 is accurately arranged in the base 222, the upper cover 221 is sealed and buckled on the base 222, and the boss 2221 can be clamped in the clamping groove 22121, so that the fixed connection of the upper cover 221 and the base 222 is completed, thereby simplifying the fixing mode of the upper cover 221 and the base 222, improving the assembly efficiency of the BDU unit 2, and ensuring the good connection firmness between the upper cover 221 and the base 222.

[0057] It can be understood that the electrical assembly 223 in the BDU unit 2 usually comprises main fuses, main relays, pre-charging relays, pre-charging resistors, shunt relays, positive temperature coefficient (PTC) relays, PTC fuses, high voltage high rupture capacity (HVH) fuses and the like, which will not be described herein again.

[0058] Optionally, the base 222 is further provided with a guide structure 2222, which is a guide rib plate shown in FIG. 8 and located at one side of the boss 2221 and extends in the second direction. During the process of buckling the upper cover body 2211 on the base 222, the guide structure 2222 is in sliding contact with the clamping structure 2212 and can guide the clamping groove 22121 to be clamped on the boss 2221, thereby effectively improving the assembly accuracy between the upper cover body 2211 and the base 222 and reducing the assembly error. In the embodiment, one guide structure 2222 is arranged at each of the opposite sides of the boss 2221 to prevent the guide structure 2222 from being deviated during the movement of the upper cover body 2211.

[0059] In order to improve the operability, in the embodiment, the clamping structure 2212 comprises a clamping plate 22122 and a rib 22123, wherein the clamping plate 22122 has the clamping groove 22121, each of the opposite sides of the clamping plate 22122 is connected to the upper cover body 2211 by a rib 22123 to form an avoiding gap 2213 between the side wall of the clamping plate 22122 and the upper cover body 2211, the clamping plate 22122 has a pressing groove 2214 at one end thereof and the upper cover body 2211, the pressing groove 2214 is in communication with the avoiding gap 2213 to enable the clamping plate 22122 to rotate around the rib 22123. Through the arrangement, when it is necessary to disassemble the upper cover 221 to maintain and repair the electrical components 223 in the base 222, the staff can press the other end of the clamping plate 22122 to rotate the clamping plate 22122 around the rib 22123, move the one end of the clamping plate 22122 outward, and form an included angle between the clamping plate 22122 and the boss 2221 which is less than 90°, thereby facilitating the disassembly of the upper cover 221.

[0060] The one end of the clamping structure 2212 facing the boss 2221 further has a first chamfer 22124, and the one end of the boss 2221 facing the clamping structure 2212 has a second chamfer 22211, the first chamfer 22124 and the second chamfer 22211 are oppositely arranged to reduce the sliding resistance between the clamping structure 2212 and the boss 2221 and facilitate the clamping of the boss 2221 in the clamping groove 22121.

[0061] In the embodiment, the upper cover body 2211 is provided with two clamping structures 2212 at two ends thereof, one of the clamping structures 2212 is provided with a pressing groove 2214, and the other clamping structure 2212 is not provided with a pressing groove 2214. In this way, the disassembly efficiency of the upper cover 221 and the base 222 is improved by simplifying one of the clamping structures 2212, and the manufacturing cost of the upper cover body 2211 is also reduced. In other embodiments, the two clamping structures 2212 can also be designed to have the pressing groove 2214 according to the actual needs of customers, and thus both the two embodiments are within the scope to be protected by the present application.

[0062] Optionally, in the embodiment, the opposite two inner side walls of the upper cover body 2211 are provided with limiting plates 2215 (only the limiting plate 2215 of one side of the upper cover body 2211 is shown in the figure) which are protruded downward. When the upper cover body 2211 is buckled on the base 222, the two limiting plates 2215 can be respectively abutted against the opposite two inner side walls of the base 222, and the two limiting plates 2215 cooperatively limit the upper cover body 2211 from being deviated along the first direction X, so as to ensure that the upper cover body 2211 is completely abutted against the base 222 without any gap. At the same time, since the upper cover 221 and the base 222 are both made of plastic material, the plastic material itself has the characteristic of deformation, so that the base 222 has a deformation characteristic of being concave inward when in use. In the embodiment, the limiting plates 2215 are provided to suppress the tendency of the base 222 to be concave inward, so as to support the side walls of the base 222 to be flat and straight, and thus the structural stability of the BDU body 22 is maintained, and the service life is prolonged.

Claims

1. A battery pack having a first direction and a second direction, the first direction being perpendicular to the second direction, the battery pack comprising: a housing (1) having a receiving cavity, a battery pack and an expansion beam (11) being arranged in the receiving cavity, the battery pack comprising a plurality of single cells (3) arranged in sequence along the first direction, and one expansion beam (11) being arranged at each end of the battery pack along the first direction, the expansion beam (11) being arranged to elastically deform along the first direction at least when the single cells (3) expand; a BDU unit (2) arranged in the receiving cavity and between the expansion beam (11) and the housing (1), the BDU unit (2) comprising a fixing frame (21), a BDU body (22) and a fastener (23), the fixing frame (21) being fixedly connected to the expansion beam (11), the BDU body (22) being provided with a sliding portion, and the fastener (23) being fixedly connected to the fixing frame (21) and slidably arranged on the sliding portion along the first direction.

2. The battery pack of claim 1, wherein, Along the second direction, the BDU body (22) is provided with a mounting waist hole (2201) arranged to form the sliding portion, and the length direction of the mounting waist hole (2201) is parallel to the first direction, the fastener (23) being arranged in the mounting waist hole (2201) and fixedly connected to the fixing frame (21), and the fastener (23) being slidably arranged in the mounting waist hole (2201).

3. The battery pack of claim 2, wherein, The fastener (23) comprises a locking bolt (231) and a pull rivet nut (232), the pull rivet nut (232) being arranged on the fixing frame (21), the locking bolt (231) being arranged in the mounting waist hole (2201) and connected to the pull rivet nut (232), and the pull rivet nut (232) comprising a first flange (2321) clamped between the BDU body (22) and the fixing frame (21).

4. The battery pack of claim 3, wherein, The fastener (23) further comprises a first screw sleeve (233), the first screw sleeve (233) comprising a screw sleeve body (2331) and a second flange (2332), the screw sleeve body (2331) being embedded in the mounting waist hole (2201), and the second flange (2332) being arranged at the end of the screw sleeve body (2331) and abutting against the BDU body (22); The locking bolt (231) comprises a stud body and a third flange (2311), the stud body being arranged in the screw sleeve body (2331) and connected to the pull rivet nut (232), and the third flange (2311) being arranged at the outer periphery of the stud body and abutting against the second flange (2332).

5. The battery pack of claim 4, wherein, The connecting part of the screw sleeve body (2331) and the second flange (2332) is provided with a first avoiding chamfer (31), and the opening of the mounting waist hole (2201) facing the second flange (2332) is provided with a second avoiding chamfer (32), and the first avoiding chamfer (31) is arranged relative to the second avoiding chamfer (32).

6. The battery pack of claim 4, wherein, The end of the screw sleeve body (2331) away from the second flange (2332) is flush with the opening of the mounting waist hole (2201) and is connected to the first flange (2321) to support the first screw sleeve (233) through the pull rivet nut (232).

7. The battery pack of claim 2, wherein, In the third direction, the BDU body (22) is provided with a plurality of mounting waist holes (2201), and the expansion beam (11) is provided with a plurality of fixing frames (21), and each mounting waist hole (2201) is fixedly connected to the fixing frame (21) through a fastener (23), the third direction is parallel to the length extension direction of the expansion beam (11), and the third direction, the second direction and the first direction are perpendicular to each other.

8. The battery pack of any one of claims 2-7, wherein, The BDU body (22) comprises a base (222) and an upper cover (221), the base (222) is provided with an electrical assembly (223), the base (222) is provided with the mounting waist hole (2201), and the side wall of the base (222) is provided with a boss (2221). The upper cover (221) comprises an upper cover body (2211) and a clamping structure (2212), the upper cover body (2211) is provided with the clamping structure (2212), the clamping structure (2212) has a clamping groove (22121), and when the upper cover body (2211) is buckled on the base (222), the boss (2221) is clamped in the clamping groove (22121).

9. The battery pack of claim 8, wherein, The base (222) is also provided with a guide structure (2222), and when the upper cover body (2211) is buckled on the base (222), the guide structure (2222) can guide the clamping groove (22121) to be clamped on the boss (2221).

10. The battery pack of claim 8, wherein, At least two inner side walls of the upper cover body (2211) are provided with limiting plates (2215) downwardly protruding, and when the upper cover body (2211) is buckled on the base (222), two limiting plates (2215) are respectively abutted on the opposite two inner side walls of the base (222).

11. The battery pack of claim 8, wherein, The clamping structure (2212) comprises a clamping plate (22122) and a rib (22123), the clamping plate (22122) has the clamping slot (22121), each of opposite sides of the clamping plate (22122) is connected to the upper cover body (2211) by a rib (22123) to form an avoiding gap (2213) between the side wall of the clamping plate (22122) and the upper cover body (2211), one end of the clamping plate (22122) and the upper cover body (2211) have a pressing slot (2214) in communication with the avoiding gap (2213) so that the clamping plate (22122) can rotate around the rib (22123).

12. The battery pack of claim 8, wherein, The clamping structure (2212) has a first chamfer (22124) at one end facing the boss (2221), the boss (2221) has a second chamfer (22211) at one end facing the clamping structure (2212), and the first chamfer (22124) and the second chamfer (22211) are oppositely arranged.

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