CN210607369U

CN210607369U - Aluminum alloy battery pack lower shell

Info

Publication number: CN210607369U
Application number: CN201921642217.7U
Authority: CN
Inventors: 段利斌; 吴闯; 龙宜凡; 江浩斌
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2019-09-29
Filing date: 2019-09-29
Publication date: 2020-05-22
Anticipated expiration: 2029-09-29

Abstract

The utility model discloses an aluminum alloy battery pack lower shell, which comprises a frame structure, a beam, a floor and a middle lifting lug; the frame structure is formed by splicing four frames with L-shaped sections; the two groups of beams are identical in structure and are arranged in parallel, the cross section of one group of beams is in an inverted T shape, the cross section of the other group of beams is in a step shape, and the two groups of beams and the L-shaped frame are connected in an overlapping mode through a male end and a female end in an inserting connection mode and then welded; the cross section of the floor is in a shape of a straight line, and is welded with the L-shaped frame and the cross beam after being spliced; the middle lifting lug comprises a middle lifting lug main body of a cylindrical hollow structure, the middle lifting lug main body penetrates through the cross beam from bottom to top, the top of the middle lifting lug main body is matched with the nut, and the circular ring piece penetrates through the middle lifting lug main body from top to bottom and is fixed by MIG welding. The utility model discloses fully absorbed the advantage of aluminum alloy, realized the lightweight design of battery package box, and connect reliably, the leakproofness is good, machining efficiency is high.

Description

Aluminum alloy battery pack lower shell

Technical Field

The utility model relates to an electric automobile technical field, concretely relates to casing under aluminum alloy battery package.

Background

With the annual output and sales of automobiles increasing year by year, the problems of energy crisis and environmental deterioration are increasingly aggravated, and the development of electric automobiles is an important way for solving the problems. However, the short driving range is a primary problem restricting the development of the electric automobile at present. The battery pack is used as one of core components of the electric automobile, the mass of the battery pack body accounts for about one third of the service mass of the whole automobile, and therefore the development of the lightweight design of the battery pack structure has important significance for improving the target endurance mileage of the electric automobile.

The existing battery pack mainly comprises three structural forms, namely a steel battery pack, an aluminum alloy die-casting battery pack and an aluminum alloy section battery pack. The steel battery pack has the advantages of low cost, high strength, good mechanical property, mature manufacturing process and the like, but has the defect of heavy weight, so that the large-scale popularization and application of the steel battery pack are limited. Aluminum alloy die-cast battery packs enable complex cross-sectional designs, but the high die cost is a major factor limiting their large-scale deployment.

The battery pack based on the aluminum alloy extruded section provides a new idea for solving the problems, and the aluminum alloy section has the advantages of light weight, low mold cost, good energy absorption effect and the like. The prior art realizes the lightness of the lower shell of the battery pack to a certain extent, but still has the defects of over-design, short service life of welding lines, complex section of a section bar, high manufacturing cost and the like.

Disclosure of Invention

In order to solve the problem, the utility model provides a casing under aluminum alloy ex-trusions battery package aims at realizing lightweight, low-cost design and the manufacturing of casing under the battery package.

The utility model adopts the following technical scheme:

the aluminum alloy battery pack lower shell comprises a frame structure, a cross beam, a floor and a middle lifting lug, wherein the frame structure is formed by splicing four frames with L-shaped cross sections; the cross beams are divided into two groups, each group of cross beams are identical in structure and arranged in parallel, the cross section of one group of cross beams is in an inverted T shape, the cross section of the other group of cross beams is in a step shape, and the two groups of cross beams and the L-shaped frame are lapped and welded by adopting a male end and female end splicing structure; the floor is in a straight-line shape in cross section, and the floor is spliced with the cross beam and the L-shaped frame and then welded; the middle lifting lug comprises a middle lifting lug main body with a cylindrical hollow structure, and the middle lifting lug main body penetrates through the inverted T-shaped cross beam from bottom to top; the bottom flange of the middle lifting lug main body is attached to the lower surface of the inverted T-shaped cross beam, the top of the middle lifting lug main body is matched with the nut, and the circular ring piece penetrates through the middle lifting lug main body from top to bottom and is fixed by MIG welding.

In the technical scheme, the section of the L-shaped frame is formed by integrally forming a mesh-shaped cavity structure and a triangular cavity structure which are sequentially arranged, and the mesh-shaped cavity structure is positioned in the inner side direction of the battery pack; the upper ribs of the cavity structure in the shape of the Chinese character 'mu' are horizontally arranged, and the lower ribs are obliquely arranged; a boss extends from the bottom of the square-shaped cavity structure along the inner side direction of the battery pack, a groove A is formed in the corner position of the bottom of the boss, the boss is of a hollow structure, belongs to a male end and is used for being inserted into and bearing a cross beam; the triangular cavity structure is provided with a lifting lug mounting hole A along the height direction of the battery pack and used for mounting a rivet nut to be in bolted connection with the frame.

In the technical scheme, the cross-section of the inverted T-shaped cross beam is formed by integrally forming a reversed-T-shaped cavity structure and a reversed-T-shaped cavity structure A, the reversed-T-shaped cavity structure is positioned in the middle, and the reversed-T-shaped cavity structure A is closely adjacent to the reversed-T-shaped cavity structure and positioned on two sides; a convex edge A and a turned edge A extend from the end part of the inverted T-shaped cross beam, and the convex edge A and the turned edge A jointly form a female end for being inserted with bosses at the bottoms of the No. 2 frame and the No. 4 frame; and the middle part of the cavity structure shaped like the Chinese character 'ri' is provided with a lifting lug mounting hole B for mounting a middle lifting lug.

In the technical scheme, the cross-section of the cross beam in the shape of the ladder is integrally formed by two cavity structures B in the shape of a Chinese character kou which are different in size and are sequentially arranged, and partial materials are cut off at the bottom edge positions of the cavity structures B in the shape of the Chinese character kou along the length direction of the cavity structures B and are used for being spliced with bosses at the bottoms of the frames 1 and 3; a convex edge B and a turned edge C extend from the end part of the step-shaped cross beam, and the convex edge B and the turned edge C jointly form a female end for being spliced with bosses at the bottoms of the No. 2 frame and the No. 4 frame; the upper part of the larger square-shaped cavity structure B is provided with a bolt hole for fixing the cushion block.

In the technical scheme, the I-shaped floor is integrally formed by the mouth-shaped cavity structures C which are sequentially arranged, and the bottom surface of the end part of the I-shaped floor extends to form a flange E for being inserted into the groove A of the boss at the bottom of the L-shaped frame.

In the technical scheme, the edge angle positions of the mouth-shaped cavity structure A with the cross section in the shape of an inverted T on the outermost side of the cross beam along the length direction of the cavity structure A are respectively provided with a groove B or a turned edge B; the cross section of the small square-shaped cavity structure B in the stepped cross beam is provided with a flanging D or a groove C along the edge angle position in the length direction; the edge positions of the two sides of the floor in the length direction are respectively provided with a flanging E and a groove D; the beam and the floor adopt a mode of inserting a flanging and a groove, wherein the flanging of the beam corresponds to the groove of the floor, and the groove of the beam corresponds to the flanging of the floor.

The utility model discloses a beneficial achievement:

1) the utility model discloses the structure aluminum alloy quantity is few, and the crossbeam adopts the grafting mode of public end, female end with the frame, has advantages such as light in weight, with low costs, welding seam fatigue life-span, part small in quantity, simple structure, provides fine solution for lightweight, low-cost design and the manufacturing of battery package.

2) The utility model discloses the structure can increase battery module quantity through the mode that increases battery package length or width and crossbeam quantity to satisfy the battery module of the nimble different quantity of installation of different demands of consumer to the continuation of the journey mileage, realize battery package platformization and modular design and manufacturing.

Drawings

Figure 1 is the utility model discloses casing shaft mapping under the aluminum alloy battery package.

Fig. 2 is a schematic view of the connection relationship of the frame structure of the present invention, fig. 2(a) is a top view of the frame structure of the present invention, fig. 2(b) is a schematic view of the frame structure of the present invention, and fig. 2(c) is a schematic view of the cross section of the frame of the present invention.

Fig. 3 is the structure schematic diagram of the cross beam of the utility model, fig. 3(a) is the utility model discloses "shape of falling T" beam structure schematic diagram, fig. 3(b) is the utility model discloses "shape of falling T" crossbeam cross-section schematic diagram, fig. 3(c) is the utility model discloses "shape of falling T" crossbeam elevation view, fig. 3(d) is the utility model discloses "shape of falling T" crossbeam tip enlarger, fig. 3(e) is the utility model discloses "ladder" shape crossbeam structure schematic diagram, fig. 3(f) is the utility model discloses "ladder" shape crossbeam cross-section schematic diagram, fig. 3(g) is the utility model discloses "ladder" shape crossbeam elevation view, fig. 3(h) is the utility model discloses "ladder" shape crossbeam tip enlarger.

Fig. 4 is a schematic structural view of the floor board of the present invention, fig. 4(a) is a schematic structural view of the floor board of the present invention, fig. 4(b) is a schematic sectional view of the floor board of the present invention, and fig. 4(c) is a front view of the floor board of the present invention; fig. 4(d) is an enlarged view of the floor end of the present invention.

Fig. 5 is the utility model discloses middle lug structure schematic diagram, and fig. 5(a) is the utility model discloses middle lug explosion chart, and fig. 5(b) is the utility model discloses middle lug assembly relation schematic diagram, fig. 5(c) is the utility model discloses middle lug is connected with last casing, "shape of falling T" crossbeam schematic diagram.

Fig. 6 is the utility model discloses structure crossbeam and frame structural connection relation sketch map, fig. 6(a) is the utility model discloses "shape of falling T" crossbeam and No. 2 frames, No. 4 frames connection relation sketch maps, fig. 6(b) is the utility model discloses "ladder" shape crossbeam and No. 2 frames, No. 4 frames connection relation sketch maps, fig. 6(c) is the utility model discloses "ladder" shape crossbeam and No. 1 frames, No. 3 frames connection relation sketch maps.

Fig. 7 is a schematic view of the connection relationship between the structural floor and the frame structure and the cross beam of the present invention, fig. 7(a) is a schematic view of the connection relationship between the floor and the frame No. 2 and the frame No. 4 of the present invention, and fig. 7(b) is a schematic view of the connection relationship between the floor and the "inverted T-shaped" cross beam and the "stepped" cross beam of the present invention;

fig. 8 is a schematic view of the assembly relationship between the battery module and the frame structure and the cross beam of the present invention.

Wherein: 100-frame structure, No. 110-1 frame, 111- 'mu' shaped cavity structure, 112-triangular cavity structure, 113-upper rib, 114-lower rib, 115-rivet nut mounting hole A, 116-small boss, 117-boss, 118-groove A, 119-lifting lug mounting hole A, 120-2 frame, 130-3 frame, 140-4 frame, 200-beam, 210- 'inverted T' beam, 211- 'Ri' shaped cavity structure, 212- 'Koujin' shaped cavity structure A, 213-rivet nut mounting hole B, 214-lifting lug mounting hole B, 215-convex edge A, 216-flanging A, 217-groove B, 218-flanging B, 220- 'ladder' shaped beam, 221- 'Koujin' shaped cavity structure B, 222-convex edge B, 223-flanging C, 224-bolt hole, 225-rivet nut mounting hole C, 226-flanging D, 227-groove C, 300-floor, 301-square-shaped cavity structure C, 302-flanging E, 303-groove D, 400-middle lifting lug, 401-middle lifting lug main body, 402-flange, 403-nut, 404-circular sheet, 405-sealing pad, 406-gasket, 500-sealing ring, 600-upper shell, 700-cushion block and 800-rivet nut.

Detailed Description

The invention is described in further detail below with reference to the drawings and specific examples.

Fig. 1 is a perspective view of a lower shell of an aluminum alloy battery pack of the present invention, which includes four parts, namely, a frame structure 100, a beam 200, a floor 300, and a middle lifting lug 400; the beam 200 and the frame structure 100 are fixed by inserting a male end and a female end and welding by MIG welding; the floor 300 is arranged between the cross beams and fixed by friction stir welding and MIG welding; the middle lifting lug 400 penetrates through the cross beam 200 from bottom to top and is fixed through MIG welding. Wherein, through the mode that increases side frame length, the quantity of crossbeam can be a plurality of to satisfy the consumer to the different demands of continuation of the journey mileage, install the battery module of different quantity in a flexible way, realize battery package platformization and modular design and manufacturing.

Fig. 2 is a schematic view of the connection relationship of the frame structure of the present invention, wherein fig. 2(a) is a schematic view of the connection relationship of the frame structure, fig. 2(b) is a schematic view of the L-shaped frame structure, and fig. 2(c) is a schematic view of the cross section of the L-shaped frame. The frame structure 100 comprises a No. 1 frame 110, a No. 2 frame 120, a No. 3 frame 130 and a No. 4 frame 140 which have the same cross-sectional shape, and the frames are spliced end to end through MIG welding to form a closed rectangular frame structure; because the cross sections of the frames have the same shape, the common use of the die can be realized during processing, thereby reducing the manufacturing cost. The cross section of each frame is L-shaped, and is formed by integrally forming a sequentially arranged mesh-shaped cavity structure 111 and a triangular cavity structure 112 (equivalent to a lifting lug), wherein the mesh-shaped cavity structure 111 is positioned in the inner side direction of the battery pack, an upper rib 113 of the mesh-shaped cavity structure 111 is horizontally arranged, a lower rib 114 is obliquely arranged, and the two ribs are favorable for sequentially transmitting the load of the battery pack to the triangular cavity structure 112 (equivalent to the lifting lug) and the vehicle body by using the fastest path. A rivet nut mounting hole A115 is formed in the upper surface of the cavity structure 111 in the shape of the Chinese character 'mu', and is used for being connected with the upper shell 600 and the sealing strip 500 through bolts; a small boss 116 which is arranged upwards is arranged at the corner position of the upper surface of the square-shaped cavity structure 111, which is close to the inner side direction of the battery pack, and is used for preventing external water vapor and dust from entering the battery pack; the bottom of the cavity structure 111 shaped like a Chinese character 'mu' extends out of a boss 117 along the inner side direction of the battery pack, a groove A118 is arranged at the corner position of the bottom of the boss 117, the boss 117 is of a hollow structure, and the boss 117 belongs to a male end and is used for being plugged and bearing the cross beam 200. The triangular cavity structure 112 is provided with a lifting lug mounting hole A119 along the height direction of the battery pack and used for mounting a rivet nut to be in bolt connection with a frame.

Fig. 3 is a schematic structural view of the cross beam of the present invention, fig. 3(a) is a schematic structural view of an "inverted T-shaped" cross beam, and fig. 3(b) is a schematic cross-sectional view of the "inverted T-shaped" cross beam; specifically, the Chinese character 'ri' shaped cavity structure 211 and the Chinese character 'kou' shaped cavity structure A212 are integrally formed, the Chinese character 'ri' shaped cavity structure 211 is positioned in the middle, the Chinese character 'kou' shaped cavity structure A212 is positioned at two sides close to the Chinese character 'ri' shaped cavity structure 211, and the number of the Chinese character 'kou' shaped cavity structures A212 is not limited; a rivet nut mounting hole B213 is formed in the upper surface of the square-shaped cavity structure A212 and used for mounting a battery module; the middle part of the hollow cavity structure 211 shaped like a Chinese character 'ri' is provided with a lifting lug mounting hole B214 for mounting the middle lifting lug 400.

Fig. 3(c) is a front view of the "inverted T" beam, the end of the "inverted T" beam 210 extends to form a convex edge a215 and a turned edge a216, as shown in fig. 3(d), the convex edge a215 and the turned edge a216 together form a female end for being inserted into the boss 117 at the bottom of the No. 2 frame 120 and the No. 4 frame 140.

Fig. 3(e) is a schematic view of a structure of a step-shaped beam, and fig. 3(f) is a schematic view of a cross section of the step-shaped beam, specifically, two different size "square" shaped cavity structures B221 which are sequentially arranged are integrally formed, and a part of material is cut off at the corner position of the bottom of the larger "square" shaped cavity structure along the length direction thereof for being inserted with the bosses a117 at the bottom of the No. 1 frame 110 and the No. 2 frame 130; fig. 3(g) is a front view of the step-shaped beam, a convex edge B222 and a turned edge B223 extend from the end of the step-shaped beam 220, and as shown in fig. 3(h), the convex edge B222 and the turned edge B223 together form a female end for inserting into the boss 117 at the bottom of the No. 2 frame 120 and the No. 4 frame 140; the upper part of the larger square-shaped cavity structure is provided with a bolt hole 224 for fixing the cushion block 700, and the upper surface of the larger square-shaped cavity structure is provided with a rivet nut mounting hole C225 for mounting the battery module.

Fig. 4 is a schematic structural view of a floor, fig. 4(a) is an isometric view of the floor, fig. 4(b) is a schematic sectional view of the floor, the sectional shape of the floor 300 is in a shape of a straight line, specifically, the floor is integrally formed by cavity structures C301 in a shape of a square with a mouth, which are sequentially arranged, fig. 4(C) is a front view of the floor 300 in a shape of a straight line, fig. 4(d) is an enlarged view of the end part of the floor, and flanges C302 extend from the bottom surface and two side surfaces of the end part of the floor 300 in a shape of a straight line and are used for being inserted into the grooves a118 of the bosses.

Fig. 5 is a schematic view of the structure of the middle lifting lug of the present invention, fig. 5(a) is an exploded view of the middle lifting lug of the present invention, and fig. 5(b) is a schematic view of the assembly relationship of the middle lifting lug of the present invention; the middle lifting lug 400 comprises a middle lifting lug main body 401 of a cylindrical hollow structure, the middle lifting lug main body 401 penetrates through the inverted-T-shaped cross beam 210 from bottom to top, and a bottom flange 402 of the middle lifting lug main body 401 is attached to the lower surface of the inverted-T-shaped cross beam 210 to realize Z-direction positioning (as shown in fig. 5 (c)). The top of the middle lifting lug is matched with a nut 403, a circular ring piece 404 penetrates through the middle lifting lug main body 401 from top to bottom and is fixed by MIG welding, and the upper shell 600 is fixed between the circular ring piece 404 and the nut 403; in actual use, a sealing gasket 405 and a gasket 406 are arranged between the circular ring piece 404 and the nut 403 to improve the sealing performance of the battery pack (as shown in fig. 5 (c)). Bolts are placed inside the middle lifting lug main body 401 and are used for being connected with a vehicle body cross beam, the middle lifting lug 400 is connected with the vehicle body cross beam, and deformation of the middle area of the battery pack can be effectively reduced.

Fig. 6 is the utility model discloses structure crossbeam and frame structural connection relation sketch map, fig. 6(a) is "shape of falling T" crossbeam 210 and No. 2 frames 120, No. 4 frames 140 relation sketch map, "shape of falling T" crossbeam 210 and No. 2 frames 120, No. 4 frames 140 adopt behind the grafting structure of "public end, female end" and MIG welding, grafting structure is first defence line, the welding seam is the second defence line, grafting structure not only is favorable to the stability of structure, avoid the welding seam to become invalid, and can improve the leakproofness of battery package.

Fig. 6(b) is a schematic view of a connection relationship between the step-shaped beam 220 and the frames 2, 4, 140, wherein the step-shaped beam 220 and the frames 2, 4, 140 adopt a plug-in structure of a male end and a female end and are subjected to MIG welding, the plug-in structure is a first defense line, the welding line is a second defense line, the plug-in structure is not only beneficial to the stability of the structure, but also avoids the failure of the welding line, and can improve the sealing performance of the battery pack. Fig. 6(c) is a schematic view of a connection relationship between the step-shaped beam 220 and the frames 1 and 3, wherein a cushion block 700 is arranged on the upper surface of the boss 117 at the bottoms of the frames 1 and 3, so that deformation of the step-shaped beam can be effectively reduced, and the cushion block 700 is welded with the upper surfaces of the bosses 117 of the frames 1 and 3, and then is connected with the bolt holes 224 of the step-shaped beam 220 by bolts.

Fig. 7 is the utility model discloses structure floor and frame structure, crossbeam connection relation sketch map, floor 300 tip lower surface extends turn-ups E302, be used for with No. 2 frame 120, No. 4 frame 140 bottom boss 117's recess A118 pegs graft (shown in fig. 7 (a)), the position department of "falling T" crossbeam 210 both sides edges and corners is equipped with recess B217 or turn-ups B218, "ladder" shape crossbeam 220 less "mouth" font cavity structure edges and corners position department is equipped with recess C227 or turn-ups D226, floor both sides edges and corners position department is equipped with recess D303 or turn-ups E302, the crossbeam adopts the grafting mode of turn-ups and recess with the floor, wherein the crossbeam turn-ups corresponds with the floor recess, the crossbeam recess corresponds with the floor turn-ups (shown in fig. 7 (B)), the grafting structure not only is favorable to the stability of structure, avoid the failure welding seam, and can improve the leakproofness of battery package.

Fig. 8 is the assembly relation schematic diagram of the battery module of the utility model discloses battery module and frame structure, crossbeam, four angular positions of battery module open and have the bolt hole, utilize the bolt and inlay in frame structure 100, the inside rivet nut 800 of crossbeam 200 carry out bolted connection, realize battery module and frame structure 100, the fastening connection of crossbeam 200.

The above is only the preferred embodiment of the present invention, it is not right the utility model discloses the restriction of embodiment, to the designer who belongs to this technical field, can also make a plurality of improvement schemes to above-mentioned embodiment, (thereby reach to expand and reduce battery package module quantity or propose a mixed structure based on similar structure, perhaps change the aluminum alloy into light materials such as magnesium alloy, engineering plastics through changing frame length or crossbeam quantity), all belong to the technical scheme under the thinking of the utility model discloses a protection scope.

Claims

1. The utility model provides a casing under aluminum alloy battery package, includes frame structure (100), crossbeam (200), floor (300) and middle lug (400), its characterized in that: the frame structure (100) is formed by splicing four frames with L-shaped cross sections; the cross beams (200) are divided into two groups, each group of cross beams are identical in structure and arranged in parallel, the cross section of one group of cross beams is in an inverted T shape, the cross section of the other group of cross beams is in a step shape, and the two groups of cross beams and the L-shaped frame are lapped and welded by adopting a male end and female end splicing structure; the cross section of the floor (300) is in a straight shape, and the floor (300) is lapped and welded with the cross beam (200) and the L-shaped frame by adopting a splicing structure of a boss and a groove; the middle lifting lug (400) comprises a middle lifting lug main body (401) with a cylindrical hollow structure, and the middle lifting lug main body (401) penetrates through the inverted T-shaped cross beam from bottom to top; a flange (402) at the bottom of the middle lifting lug main body (401) is attached to the lower surface of the inverted T-shaped beam (210), the top of the middle lifting lug main body is matched with a nut (403), and a circular ring piece (404) penetrates through the middle lifting lug main body (401) from top to bottom and is fixed by MIG welding.

2. The aluminum alloy battery pack lower case according to claim 1, wherein: the section of the L-shaped frame is formed by integrally forming a mesh-shaped cavity structure (111) and a triangular cavity structure (112) which are sequentially arranged, and the mesh-shaped cavity structure (111) is positioned in the inner side direction of the battery pack; the upper ribs (113) of the square-shaped cavity structure are horizontally arranged, and the lower ribs (114) are obliquely arranged; a boss (117) extends out of the bottom of the square-shaped cavity structure (111) along the inner side direction of the battery pack, a groove A (118) is formed in the corner position of the bottom of the boss (117), the boss (117) is of a hollow structure, and the boss (117) belongs to a male end and is used for being inserted into and bearing the cross beam (200); the triangular cavity structure (112) is provided with a lifting lug mounting hole A (119) along the height direction of the battery pack and used for mounting a blind rivet nut to be in bolt connection with the frame.

3. The aluminum alloy battery pack lower case according to claim 1, wherein: the cross beam with the inverted T-shaped cross section is formed by integrally forming a reversed-T-shaped cavity structure (211) and a square-shaped cavity structure A (212), the reversed-T-shaped cavity structure (211) is located in the middle, and the square-shaped cavity structure A (212) is located on two sides of the reversed-T-shaped cavity structure in a close proximity mode; the end part of the inverted T-shaped beam (210) extends to form a convex edge A (215) and a turned edge A (216), the convex edge A (215) and the turned edge A (216) jointly form a female end which is used for being spliced with bosses (117) at the bottoms of the No. 2 frame (120) and the No. 4 frame (140); and a lifting lug mounting hole B (214) is formed in the middle of the hollow cavity structure (211) in the shape of the Chinese character 'ri', and is used for mounting a middle lifting lug (400).

4. The aluminum alloy battery pack lower case according to claim 1, wherein: the cross section of the cross beam is in a ladder shape, and is integrally formed by two opening-shaped cavity structures B (221) which are arranged in sequence and have different sizes, and partial materials are cut off at the bottom edge positions of the larger opening-shaped cavity structures B (221) along the length direction of the bottom edge positions of the opening-shaped cavity structures B (221) and are used for being spliced with bosses (117) at the bottoms of the No. 1 frame (110) and the No. 3 frame (130); a convex edge B (222) and a turned edge C (223) extend out of the end part of the step-shaped cross beam, the convex edge B (222) and the turned edge C (223) jointly form a female end for being spliced with bosses (117) at the bottoms of the No. 2 frame (120) and the No. 4 frame (140); the upper part of the larger square cavity structure B (221) is provided with a bolt hole (224) for fixing the cushion block (700).

5. The aluminum alloy battery pack lower case according to claim 1, wherein: the I-shaped floor (300) is formed by integrally forming a mouth-shaped cavity structure C (301) which are sequentially arranged, and a flanging E (302) extends from the bottom surface of the end part of the I-shaped floor (300) and is used for being spliced with a groove A (118) of a boss (117) at the bottom of a No. 2 frame (120) and a No. 4 frame (140).

6. The aluminum alloy battery pack lower case according to any one of claims 1, 3, 4, and 5, wherein: the edge angle positions of the outermost square-shaped cavity structure A (212) of the cross section of the cross beam with the shape of the inverted T are respectively provided with a groove B (217) or a flanging B (218) along the length direction; a flanging D (226) or a groove C (227) is respectively arranged at the edge angle position of the smaller square-shaped cavity structure B (221) in the cross beam with the cross section in the shape of a ladder along the length direction; the edge corners of the floor in the length direction at two sides are respectively provided with a flanging E (302) and a groove D (303); the beam (200) and the floor (300) adopt a mode of inserting a flanging and a groove, wherein the flanging of the beam corresponds to the groove of the floor, and the groove of the beam corresponds to the flanging of the floor.