CN115939630A - Battery pack, manufacturing method thereof and vehicle - Google Patents

Abstract

The invention provides a battery pack, a manufacturing method thereof and a vehicle, wherein the battery pack comprises a tray, a frame, a supporting structure and a battery cell, the frame encloses to form an installation space matched with the appearance of the tray so as to fix the frame at the periphery of the tray, the frame is abutted against the outer surface of the side wall of the tray, the bottom surface of the supporting structure is fixed at the upper surface of the bottom wall of the tray, and the periphery of the supporting structure is fixed at the inner surface of the side wall of the tray so as to divide the loading space of the tray into a plurality of positioning cavities for placing the battery cell. The battery pack provided by the invention has better strength and rigidity, can well meet the requirement of light weight, reduces energy consumption and improves safety.

Description

Battery pack, manufacturing method thereof and vehicle

Technical Field

The invention relates to the technical field of batteries of new energy vehicles, in particular to a battery pack, a manufacturing method of the battery pack and a vehicle with the battery pack.

Background

The power battery box is a bearing part of a new energy automobile power battery, consists of an upper cover and a lower shell, and is mainly used for protecting the lithium battery from being damaged when the lithium battery is collided and extruded from the outside. The battery box is used as a bearing body of the battery module and plays a key role in the safe operation and protection of the battery module.

At present, two types of aluminum alloy and steel battery packs mainly exist in the market. The aluminum alloy has the advantages of excellent processability, corrosion resistance, recyclability and the like, so that the application of the aluminum alloy material to power battery box products becomes the mainstream at present, and aluminum plates, extruded aluminum and cast aluminum of three different types are applied in batches on different projects. However, with the new energy subsidy of landslide and the policy of quitting 2022, the high cost of the aluminum alloy raw materials becomes a great adverse factor. In addition, the preparation of the aluminum alloy material is not beneficial to the requirements of energy conservation and environmental protection. After the collision extrusion, the aluminum alloy material has the property that the aluminum alloy material faces a larger problem in dealing with the combustion hindering working condition. Although the strength of the common steel shell is high, the safety of the power battery can be well protected, the self weight of the common steel shell is large, so that the whole vehicle is high in servicing quality, and the endurance and the energy consumption of the electric vehicle are influenced.

Disclosure of Invention

In view of the above, the present invention provides a battery pack, a method of manufacturing the battery pack, and a vehicle having the battery pack, which have good strength and rigidity, and can well satisfy the requirement of light weight, reduce energy consumption, and improve safety.

The technical scheme of the invention is as follows:

the invention provides a battery pack which comprises a tray, a frame, a supporting structure and a battery cell, wherein the frame is enclosed to form an installation space matched with the appearance of the tray so as to fix the frame on the periphery of the tray, the frame is abutted against the outer surface of the side wall of the tray, the bottom surface of the supporting structure is fixed on the upper surface of the bottom wall of the tray, and the periphery of the supporting structure is fixed on the inner surface of the side wall of the tray so as to divide the loading space of the tray into a plurality of positioning cavities for placing the battery cell.

Further, the tray comprises a side wall, a bottom wall and a flange outer edge, wherein the bottom side of the side wall is enclosed on the periphery of the bottom wall to form a loading space of the tray, the flange outer edge is enclosed on the periphery of the top side of the side wall, and the side wall, the bottom wall and the flange outer edge are made of steel plates through hot forming and stamping.

Furthermore, a triangular surface is formed at the boundary position between the corner of the side wall and the bottom wall.

Further, when the side wall draft angle β is 8 °, the triangular face draft angle γ ranges from 35 ° to 40 °; when the sidewall draft angle β is 12 °, the triangular face draft angle γ ranges from 30 ° to 40 °.

Further, the frame is including being the first welding wall, interior support wall, outer wall, lower support wall, inner wall, go up support wall, last outer wall and the second welding wall that "day" style of calligraphy cross section structure connects gradually, and the internal surface welded fastening of first welding wall and inner wall, second welding wall and interior support wall weld for outer wall and the outer wall of last outer wall form the outer wall of frame jointly down, and interior support wall supports between the outer wall and the inner wall of frame.

Further, bearing structure includes crossbeam and longeron, and the bottom surface of crossbeam and longeron all welds in the diapire upper surface, and the both ends of crossbeam and longeron all weld in the lateral wall internal surface.

Further, still include the liquid cooling board, the liquid cooling board adopts the steel sheet to press into the containment structure who has the cooling bath, and the cooling bath is the tortuous extension and is covered with the liquid cooling board, and the liquid cooling board edge is run through at the both ends of cooling bath to form feed liquor hole and play liquid hole respectively, liquid cooling board seal weld in the diapire lower surface of tray, the diapire be formed with the cooling bath one-to-one protruding muscle, protruding muscle is inwards gone into the cooling bath down, protruding muscle and cooling bath cooperate and form the passageway that supplies the cooling liquid circulation.

Furthermore, the liquid cooling plate further comprises a bottom reinforcing member, and two ends of the bottom reinforcing member are fixed on the frame to support the liquid cooling plate and the tray.

The invention also provides a manufacturing method of the battery pack, which comprises the following steps:

firstly, connecting a hot forming tray obtained by stamping according to technological parameters with a liquid cooling plate by adopting a rolling welding process, and welding the tray on a frame;

welding the support structure in the tray;

then, fixing the bottom reinforcing member and the bottom shield on the frame, and welding the bottom reinforcing member and the bottom shield;

placing a heating film in the tray or sticking the heating film on the bottom surface of the battery core, and then placing the battery cores into the positioning cavity one by one;

and the top cover and the support structure are fixed on the frame and the support structure by using bolts, so that the whole assembly of the battery pack is completed.

The invention also provides a vehicle which comprises the battery pack.

The invention has the beneficial effects that:

according to the battery pack provided by the invention, the frame is arranged on the periphery of the tray and abuts against the outer surface of the side wall of the tray, the supporting structure is arranged in the tray and abuts against the inner surface of the side wall of the tray and the upper surface of the tray, and the side wall of the tray is clamped by the frame and the supporting structure together and is matched with the bottom wall of the tray under the support of the supporting structure, so that the strength and rigidity of the battery pack are improved, the light weight requirement is met, the energy consumption is reduced, and the safety is improved. Through a plurality of location chambeies that loading space partition of bearing structure with the tray supplied electric core to put into, can effectively protect electric core like this, satisfy all kinds of extrusion, collision and the different requirements of bottom invasion operating mode, further improve the security and the reliability of battery package.

By adopting the manufacturing method of the battery pack, the assembling steps are reasonable, the operation is convenient, and the production efficiency and the product quality of the battery pack are improved.

Preferred embodiments of the present invention and advantageous effects thereof will be described in further detail with reference to specific embodiments.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings, there is shown in the drawings,

fig. 1 is a partial assembly view of a battery pack according to the present invention;

fig. 2 is a partially exploded view of a battery pack according to the present invention;

FIG. 3 is a perspective view of a prior art rounded square tray;

FIG. 4 isbase:Sub>A partial cross-sectional view taken along line A-A of FIG. 3;

FIG. 5 is a perspective view of a triangular face square tray of the present invention;

FIG. 6 is a partial cross-sectional view taken along line B-B of FIG. 5;

fig. 7 is a cross-sectional view of a frame of a battery pack of the present invention;

fig. 8 is an overall assembly view of the battery pack according to the present invention;

fig. 9 is an overall exploded view of the battery pack of the present invention;

fig. 10 is a sectional view of a battery pack according to the present invention;

fig. 11 is a partially enlarged view of fig. 10.

The reference numbers illustrate: the tray comprises a tray 1, a frame 2, a supporting structure 3, a side wall 11, a bottom wall 12, a positioning cavity 10, a flange outer edge 13, a triangular surface 14, a side wall draft angle alpha, a side wall draft angle beta, a triangular surface draft angle gamma, a first welding wall 21, an inner supporting wall 22, a lower outer wall 23, a lower supporting wall 24, an inner wall 25, an upper supporting wall 26, an upper outer wall 27, a second welding wall 28, a groove 29, a lifting lug 20, a cross beam 31, a longitudinal beam 32, a liquid cooling plate 4, a cooling tank 41, a liquid inlet hole 42, a liquid outlet hole 43, a convex rib 15, a bottom reinforcing member 5, a bottom shield 6 and a top cover 7.

Detailed Description

The following describes in detail embodiments of the present invention with reference to the drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Referring to fig. 1 and 2, the present invention provides a battery pack, which includes a tray 1, a frame 2, a supporting structure 3 and a battery cell, wherein the frame 2 encloses a mounting space adapted to the shape of the tray 1 to fix the frame 2 to the periphery of the tray 1, so that the frame 2 abuts against the outer surface of the sidewall 11 of the tray 1. The bottom surface of the supporting structure 3 is fixed on the upper surface of the bottom wall 12 of the tray 1, and the periphery of the supporting structure 3 is fixed on the inner surface of the side wall 11 of the tray 1, so as to divide the loading space of the tray 1 into a plurality of positioning cavities 10 for placing the battery core.

According to the battery pack provided by the invention, the frame 2 is arranged on the periphery of the tray 1 and abuts against the outer surface of the side wall of the tray 1, the supporting structure 3 is arranged in the tray 1 and abuts against the inner surface of the side wall of the tray 1 and the upper surface of the tray 1, and the side wall of the tray 1 is under the common clamping action of the frame 2 and the supporting structure 3 and is matched with the bottom wall 12 of the tray 1 under the support of the supporting structure 3, so that the strength and rigidity of the battery pack are improved, the light weight requirement is met, the energy consumption is reduced, and the safety is improved. Through a plurality of location chambeies 10 that supply electric core to put into are separated into with the loading space of tray 1 through bearing structure 3, can effectively protect electric core like this, satisfy all kinds of extrusion, collision and the different requirements of bottom invasion operating mode, further improve the security and the reliability of battery package.

In this embodiment, the tray 1 includes a side wall 11, a bottom wall 12 and a flange outer edge 13, the bottom side of the side wall 11 surrounds the periphery of the bottom wall 12 to form a loading space of the tray 1, the flange outer edge 13 surrounds the periphery of the top side of the side wall 11, and the side wall 11, the bottom wall 12 and the flange outer edge 13 are made of steel plates through hot forming and stamping. Alternatively, the flange outer edge 13 may fix the tray 1 to the frame 2 by bolts, but is not limited thereto, and the flange outer edge 1 may fix the tray 1 to the frame 2 by riveting, welding, or other fixing methods.

Since the pallet 1 is made by hot forming and stamping a steel plate, consideration of the formability of the material during stamping is inevitably required. In order to facilitate placing more cells and improve the energy density of the battery system, the larger the effective volume of the tray 1 is, the better the tray 1 should have good forming performance. Analysis of the tray 1 using the forming analysis software found that the interface between the corners of the side walls 11 and the bottom wall 12 was most susceptible to cracking and wrinkling during forming. In order to ensure that the material thinning rate at each position can meet the design requirement when the boundary position between the corner of the side wall 11 and the bottom wall 12 is formed by the material, and simultaneously, the effective volume of the tray 1 is not sacrificed, the invention firstly provides that the triangular surface 14 is designed at the boundary position between the corner of the side wall 11 and the bottom wall 12, and a reasonable range is analyzed. Referring to fig. 3 to 6, the tray of the battery pack of the present invention is hexagonal, and the hexagonal tray and the square tray have the same technical effect by adopting the triangular design, and for the convenience of comparative analysis, the following is described by taking the square tray as an example, specifically as follows:

in this embodiment, the basic parameters of the square tray are as follows:

depth of tray mm	Flange outer edge dimension mm	Thickness of material (mm)	R1(mm)	R2(mm)
					120	1210*1746	1.0	20	15

The above table is the basic parameters of the tray model created by the simulation analysis of the present invention. In order to compare the merits and disadvantages of the two tray schemes more intuitively, the key parameters of the two tray schemes need to be designed and corresponding analysis needs to be carried out, which is as follows:

the following table II shows simulation analysis of the existing fillet design scheme:

serial number	Side wall draft angle alpha DEG	Side wall included angle radius mm	Effective area m 2	Maximum reduction ratio%
					1	8	300	1.300	14.2
2	12	225	1.399	14.7
					3	8	150	1.511	25.3
4	8	200	1.439	19.6

The third table below is a simulation analysis of the triangular surface design scheme of the invention:

from the comparative analysis results in table two and table three, it can be seen that:

by adopting the round corner design scheme, when the side wall draft angle alpha is 8 degrees and the included angle radius of the side wall is less than or equal to 200mm, the maximum thinning rate is larger than the threshold value of 15 percent, so that the forming performance can not be met although the effective area is increased; when the side wall draft angle alpha is 12 degrees, the included angle radius of the side wall is 225mm, the effective area is not obviously increased, but the thinning rate is close to the critical value of 15 percent.

For the triangular surface design scheme, when the side wall draft angle beta is 8 degrees and the triangular surface draft angle gamma is 35 degrees, the maximum thinning rate is 14.1 percent, the design requirement is met, and the effective area is obviously increased compared with a fillet design scheme; when the triangular face draft angle gamma is less than or equal to 30 degrees, the effective area is not increased obviously, the maximum thinning rate exceeds the critical value by 15 percent, and the risk of forming and cracking exists.

In addition, when the side wall draft angle beta is 12 degrees and the triangular face draft angle gamma is more than or equal to 30 degrees, the maximum thinning rate is less than the critical value of 15 percent, the design requirement is met, and compared with a fillet design scheme, the effective area is also obviously increased; when the triangular face draft angle gamma is less than or equal to 25 degrees, the effective area is not obviously increased, the maximum thinning rate exceeds the critical value by 15 percent, and the risk of forming and cracking exists.

Therefore, when the triangular surface design scheme is adopted, when the side wall draft angle beta is 8 degrees, the triangular surface draft angle gamma ranges from 35 degrees to 40 degrees; when the sidewall draft angle β is 12 °, the triangular face draft angle γ ranges from 30 ° to 40 °.

Effective area definition: the tray bottom is horizontal, and the tray fillet area arc line or triangular surface sideline midpoint connecting line encloses the region, and the dotted line rectangular area in the figure is the effective area. Since the outer edge sizes of the designed trays 1 are the same, the depths of the designed trays 1 are also the same, but the effective areas of the bottoms of the designed trays 1 are different, so that the effective volumes are different.

The raw materials used by the steel battery pack designed by the invention are hot forming steel basal bodies, and the basal body comprises the following components in percentage by mass: 0.1 to 0.5; si:0.1 to 0.5; mn:0.5 to 2.0; p is less than or equal to 0.01; s is less than or equal to 0.01; the microalloy elements are added by alloying elements such as Ti, nb, V, ni, mo and the like or any combination thereof, the sum of Ti + Nb + V + Ni + Mo is less than or equal to 1, and the balance is Fe and inevitable impurities.

The thickness range of the steel plate used for pressing the tray 1 is 0.5-1.5 mm, and the surface state of the steel is an Al-Si coating, because the corrosion effect of the Al-Si coating to a cooling liquid is obviously better than that of other coating products or non-coating products.

The tray preparation process comprises the following steps: blanking → heating → transferring → stamping → pressure maintaining and quenching → laser cutting → tray finished product.

The thermal forming heating process comprises the steps of heating to 870-950 ℃, keeping the temperature for 2-10 min, transferring the material sheet to a press die after heating, then carrying out stamping and die assembly, keeping the pressure in the die for a period of time, keeping the pressure for 5-20 s, and transferring the formed part to a laser cutting machine for laser trimming. The mechanical properties of the tray after thermoforming are as follows: rp0.2 is more than or equal to 950MPa; rm is more than or equal to 1350MPa; a80 is more than or equal to 5 percent.

A triangular surface 14 is formed at the boundary position between the corner of the side wall 11 and the bottom wall 12 of the tray 1, and when the side wall draft angle beta is 8 degrees, the range of the triangular surface draft angle gamma is more than or equal to 35 degrees; when the side wall draft angle beta is 12 degrees, the triangular face draft angle gamma is more than or equal to 30 degrees. Therefore, the technical possibility of hot forming the steel tray is realized, and the contradiction relation between the forming performance and the effective volume of the traditional steel tray is solved. By using the tray scheme of the invention, the steel tray is ensured to have high effective volume, and good forming performance in the stamping process is ensured. Compare traditional aluminum alloy or mild steel material, use the hot forming steel material, tray intensity promotes by a wide margin to the anti bottom foreign matter invasion ability of tray has been strengthened, the security and the reliability of battery package have been improved.

Referring to fig. 7, in the present embodiment, the frame 2 is formed by rolling a steel plate, the frame 2 includes a first welding wall 21, an inner supporting wall 22, a lower outer wall 23, a lower supporting wall 24, an inner wall 25, an upper supporting wall 26, an upper outer wall 27, and a second welding wall 28, which are sequentially connected in a cross-sectional structure of a shape like a Chinese character ri, the first welding wall 21 is welded and fixed to an inner surface of the inner wall 25, the second welding wall 28 is welded to the inner supporting wall 22, so that the lower outer wall 23 and the upper outer wall 2 jointly form an outer wall of the frame 2, and the inner supporting wall 22 is supported between the outer wall and the inner wall 25 of the frame 2. Optionally, the lower outer wall 23 and the upper outer wall 27 are each formed with a groove 29 to further improve the structural strength and rigidity of the bezel 2. The side wall 11 of the tray 1 abuts against the inner wall 25, and the flange outer edge 13 of the tray 1 is fixed to the upper support wall 26. Through analysis and verification, the frame 2 adopting the cross section structure shaped like the Chinese character ri can meet the strict extrusion collision working condition, the requirement on a roller pressing die is low under the condition of ensuring the production efficiency, the strength and the rigidity are better, the interior of the battery pack can be well protected, and the safety and the reliability of the battery pack are further improved. As shown in fig. 1, a plurality of lifting lugs 20 are fixed to the outer wall of the rim 2 for easy assembly.

Referring to fig. 1 and fig. 2, in the present embodiment, the supporting structure 3 includes a cross beam 31 and a longitudinal beam 32, bottom surfaces of the cross beam 31 and the longitudinal beam 32 are welded to an upper surface of the bottom wall 12 of the tray 1, two ends of the cross beam 31 and two ends of the longitudinal beam 32 are welded to inner surfaces of the side walls 11 of the tray 1, and the longitudinal beam 32 is arranged perpendicular to the cross beam 31 to divide a loading space of the tray 1 into a plurality of positioning cavities 10 for placing the battery cells. It will be understood that the support structure 3 is not limited to the above-described structural forms, for example, the support structure 3 may also be provided with only the cross beams 31 or only the longitudinal beams 32. Alternatively, the cross beam 31 and the longitudinal beam 32 can be both made of steel plates and pressed into a cross-sectional structure shaped like a Chinese character 'ji'.

Referring to fig. 8 and 11, in the present embodiment, the battery pack further includes a liquid cooling plate 4, the liquid cooling plate 4 is made of a steel plate and is pressed into a container structure having a cooling tank 41, the cooling tank 41 is extended and zigzag distributed over the liquid cooling plate 4, and two ends of the cooling tank 41 penetrate through the edge of the liquid cooling plate 4 to form a liquid inlet hole 42 and a liquid outlet hole 43, respectively. The liquid cooling plate 4 is welded on the lower surface of the bottom wall 12 of the tray 1 in a sealing mode, the bottom wall 12 is provided with convex ribs 15 which correspond to the cooling grooves 41 one by one, the convex ribs 15 downwards protrude into the cooling grooves 41, and the convex ribs 15 are matched with the cooling grooves 41 to form channels for cooling liquid to circulate. The cooling liquid enters the cooling tank 41 through the liquid inlet hole 42 to cool the tray 1 and the battery core, and then flows out from the liquid outlet hole 43. The bottom wall 12 of the tray 1 is provided with the convex ribs 15 corresponding to the cooling grooves 41, so that the flatness, the structural strength and the rigidity of the inner side of the bottom wall 12 of the tray are improved, and the safety and the reliability of the battery pack are improved. The structure that the convex ribs 15 are matched with the cooling grooves 41 to form channels for cooling liquid to circulate can increase the heat dissipation area and improve the heat dissipation efficiency of the battery pack while ensuring the flow rate of the cooling liquid, and is conveniently realized by the conventional roll-pressing welding.

In this embodiment, the battery pack of the present invention further includes a bottom stiffener 5, and two ends of the bottom stiffener 5 are fixed to the bottom surface of the frame 2 to support the liquid cooling plate 4 and the tray 1. This can further improve the bonding strength and rigidity between the frame 2 and the tray 1.

In this embodiment, the battery pack of the present invention further includes a bottom shield 6, the periphery of the bottom shield 6 is fixed to the bottom surface of the frame 2, and the bottom shield 6 is welded to the bottom reinforcement 5. The liquid cooling plate 4 and the tray 1 can be protected by the bottom shield 6, so that the bottom foreign matter invasion resistance of the tray is enhanced, and the safety and the reliability of the battery pack are improved.

In this embodiment, the battery pack further includes a top cover 7, the periphery of the top cover 7 is fixed to the frame 2 through bolts, and the top cover 7 and the support structure 3 are fixed through bolts to fix the battery cell in the positioning cavity 10.

The tray 1, the frame 2, the supporting structure 3, the liquid cooling plate 4, the bottom reinforcing part 5, the bottom shield 6 and the top cover 7 of the battery pack can be formed by pressing and welding steel plates to form the battery pack with an all-steel structure.

The invention also provides a manufacturing method of the battery pack, which comprises the following steps:

firstly, connecting a hot forming tray 1 obtained by stamping according to technological parameters with a liquid cooling plate 4 by adopting a rolling welding process, and welding the tray 1 on a frame 2;

welding the supporting structure 3 in the tray 1;

then, fixing the bottom reinforcement 5 and the bottom shield 6 on the frame 2, and welding the bottom reinforcement 5 and the bottom shield 6;

placing a heating film in the tray 1 or sticking the heating film on the bottom surface of the battery core, and then placing the battery cores into the positioning cavity 10 one by one;

and the top cover 7 is fixed on the frame 2 and the supporting structure 3 by bolts, so that the integral assembly of the battery pack is completed.

By adopting the manufacturing method of the battery pack, the assembling steps are reasonable, the operation is convenient, and the production efficiency and the product quality of the battery pack are improved.

The invention also provides a vehicle using the battery pack, and the vehicle comprises an electric vehicle, a hybrid vehicle and the like.

In the description of the present invention, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first", "second", and the like are used for descriptive purposes only and are not to be construed as indicating or implying importance; the words "bottom" and "top", "inner" and "outer" refer to directions toward and away from, respectively, a particular component geometry.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the communication may be direct, indirect via an intermediate medium, or internal to both elements. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The utility model provides a battery pack, a serial communication port, including tray (1), frame (2), bearing structure (3) and electric core, frame (2) enclose to close the installation space who forms with tray (1) appearance looks adaptation to be fixed in tray (1) periphery with frame (2), make frame (2) support and hold in lateral wall (11) surface of tray (1), bearing structure (3) bottom surface is fixed in diapire (12) upper surface of tray (1), bearing structure (3) periphery is fixed in lateral wall (11) internal surface of tray (1), in order to separate into a plurality of location chambeies (10) with the loading space of tray (1), in order to put into electric core.

2. The battery pack according to claim 1, wherein the tray (1) comprises a side wall (11), a bottom wall (12) and a flange outer edge (13), wherein the bottom side of the side wall (11) is enclosed around the periphery of the bottom wall (12) to form a loading space of the tray (1), the flange outer edge (13) is enclosed around the periphery of the top side of the side wall (11), and the side wall (11), the bottom wall (12) and the flange outer edge (13) are made of steel plates through hot forming and stamping.

3. A battery pack according to claim 1, wherein a triangular surface (14) is formed at the boundary between the corner of the side wall (11) and the bottom wall (12).

4. The battery pack according to claim 3, wherein when the sidewall draft angle (β) is 8 °, the triangular face draft angle (γ) ranges from 35 ° to 40 °; when the sidewall draft angle (β) is 12 °, the triangular face draft angle (γ) ranges from 30 ° to 40 °.

5. The battery pack according to claim 1, wherein the frame (2) comprises a first welding wall (21), an inner supporting wall (22), a lower outer wall (23), a lower supporting wall (24), an inner wall (25), an upper supporting wall (26), an upper outer wall (27) and a second welding wall (28) which are sequentially connected in a cross-sectional structure shaped like a Chinese character ri, the first welding wall (21) is welded and fixed with the inner surface of the inner wall (25), the second welding wall (28) is welded with the inner supporting wall (22), so that the lower outer wall (23) and the upper outer wall (2) together form the outer wall of the frame (2), and the inner supporting wall (22) is supported between the outer wall and the inner wall (25) of the frame (2).

6. The battery pack according to claim 1, wherein the support structure (3) comprises a cross beam (31) and a longitudinal beam (32), the bottom surfaces of the cross beam (31) and the longitudinal beam (32) are welded to the upper surface of the bottom wall (12), and the two ends of the cross beam (31) and the longitudinal beam (32) are welded to the inner surface of the side wall (11).

7. The battery pack according to claim 1, further comprising a liquid cooling plate (4), wherein the liquid cooling plate (4) is formed by pressing a steel plate into a container structure with a cooling groove (41), the cooling groove (41) extends in a zigzag manner to be full of the liquid cooling plate (4), two ends of the cooling groove (41) penetrate through the edge of the liquid cooling plate (4) to form a liquid inlet hole (42) and a liquid outlet hole (43), the liquid cooling plate (4) is welded to the lower surface of the bottom wall (12) of the tray (1) in a sealing manner, the bottom wall (12) is provided with ribs (15) corresponding to the cooling groove (41) one by one, the ribs (15) protrude downwards into the cooling groove (41), and the ribs (15) are matched with the cooling groove (41) to form a channel for the circulation of cooling liquid.

8. The battery pack according to claim 7, further comprising a bottom reinforcement (5), wherein both ends of the bottom reinforcement (5) are fixed to the frame (2) to support the liquid-cooled plate (4) and the tray (1).

9. The manufacturing method of the battery pack is characterized by comprising the following steps:

firstly, connecting a hot forming tray (1) obtained by stamping according to technological parameters with a liquid cooling plate (4) by adopting a rolling welding process, and welding the tray (1) on a frame (2);

welding the supporting structure (3) in the tray (1);

then, fixing the bottom reinforcing member (5) and the bottom shield (6) on the frame (2), and welding the bottom reinforcing member (5) and the bottom shield (6);

a heating film is placed in the tray (1) or the heating film is pasted on the bottom surface of the battery cell, and then the battery cells are placed in the positioning cavity (10) one by one;

and the top cover (7) is fixed on the frame (2) and the supporting structure (3) by bolts, so that the integral assembly of the battery pack is completed.

10. A vehicle characterized by comprising the battery pack according to any one of claims 1 to 8.

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