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 new energy vehicle batteries, in particular to a battery pack, a method for manufacturing the battery pack, and a vehicle with the battery pack.

Background technique

The power battery box is the carrier of the new energy vehicle power battery. It consists of an upper cover and a lower case. It is mainly used to protect the lithium battery from damage when it is impacted or squeezed by the outside world. As the carrier of the battery module, the battery box plays a key role in the safe operation and protection of the battery module.

At present, there are mainly two types of aluminum alloy and steel battery packs in the market. Aluminum alloy benefits from its excellent processability, corrosion resistance and recyclability, making the application of aluminum alloy materials in power battery box products become the mainstream at present. There are three different types of aluminum plates, extruded aluminum and cast aluminum Aluminum materials have been applied in batches on different projects. However, with the decline of new energy subsidies and the complete exit policy by the end of 2022, the high cost of aluminum alloy raw materials has become a great unfavorable factor. In addition, the preparation of aluminum alloy materials is not conducive to the needs of energy saving and environmental protection. After the collision and extrusion, the properties of the aluminum alloy material make it also face a big problem in dealing with the combustion obstruction condition. Although the ordinary steel shell has high strength and can well protect the safety of the power battery, its heavy weight leads to a large curb weight of the vehicle, which affects the battery life and energy consumption of electric vehicles.

Contents of the invention

In view of the above, the present invention provides a battery pack, a method for manufacturing the battery pack, and a vehicle with the battery pack, which not only have good strength and rigidity, but also can well meet the demand for lightweight, reduce energy consumption, and improve safety. sex.

Technical scheme of the present invention:

The present invention provides a battery pack, including a tray, a frame, a supporting structure, and a battery cell. The frame surrounds and forms an installation space suitable for the shape of the tray, so that the frame is fixed on the periphery of the tray, so that the frame is held against the side wall of the tray. The outer surface and the bottom surface of the supporting structure are fixed on the upper surface of the bottom wall of the tray, and the outer 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 multiple positioning cavities for placing batteries.

Further, the tray includes a side wall, a bottom wall and a flange outer edge, the bottom side of the side wall is enclosed by the periphery of the bottom wall to form a loading space for the tray, the flange outer edge is enclosed by the outer periphery of the top side of the side wall, and the side wall , The bottom wall and the outer edge of the flange are made of steel plate thermoforming stamping.

Further, a triangular surface is formed at the junction between the corner of the side wall and the bottom wall.

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

Further, the frame includes a first welded wall, an inner support wall, a lower outer wall, a lower support wall, an inner wall, an upper support wall, an upper outer wall, and a second welded wall that are sequentially connected in a "day"-shaped cross-sectional structure. The first welded wall is welded and fixed to the inner surface of the inner wall, and the second welded wall is welded to the inner support wall so that the lower outer wall and the upper outer wall together form the outer wall of the frame, and the inner support wall is supported between the outer wall and the inner wall of the frame.

Further, the support structure includes a beam and a longitudinal beam, the bottom surfaces of the beam and the longitudinal beam are welded to the upper surface of the bottom wall, and both ends of the beam and the longitudinal beam are welded to the inner surface of the side wall.

Further, it also includes a liquid cooling plate, the liquid cooling plate is pressed into a container structure with a cooling groove, the cooling groove extends in a zigzag manner and is covered with the liquid cooling plate, and the two ends of the cooling groove run through the edge of the liquid cooling plate to respectively form a Holes and liquid outlet holes, the liquid cooling plate is sealed and welded to the lower surface of the bottom wall of the tray, and the bottom wall is formed with ribs that correspond to the cooling tank one by one, and the ribs protrude downward into the cooling tank, and the ribs match the cooling tank Create channels for coolant to circulate.

Further, a bottom reinforcement is also included, and the two ends of the bottom reinforcement are fixed to the frame to support the liquid cooling plate and the tray.

The present invention also provides a method for manufacturing a battery pack, comprising the following steps:

First, the thermoformed tray stamped according to the process parameters is connected to the liquid cooling plate by rolling welding process, and the tray is welded to the frame;

Then weld the support structure in the tray;

Then, fix the bottom reinforcement and the bottom shield to the frame, and weld the bottom reinforcement and the bottom shield;

Put the heating film in the tray or stick the heating film on the bottom surface of the cell, and then put the cells into the positioning cavity one by one;

Use bolts to fix the top cover to the frame and support structure to complete the overall assembly of the battery pack.

The present invention also provides a vehicle, including the above-mentioned battery pack.

Beneficial effects of the present invention:

In the battery pack provided by the present invention, a frame is set on the outer periphery of the tray to hold against the outer surface of the side wall of the tray, and a support structure is set in the tray to hold against the inner surface of the side wall of the tray and the upper surface of the tray. Under the common clamping effect of the structure, and with the support of the bottom wall of the tray under the support of the supporting structure, the strength and rigidity of the battery pack are improved, which meets the demand for lightweight, reduces energy consumption, and improves safety. The supporting structure divides the loading space of the tray into multiple positioning cavities where the power supply core is placed, which can effectively protect the battery core, meet the different requirements of various extrusion, collision and bottom intrusion conditions, and further improve the safety of the battery pack and reliability.

By adopting the manufacturing method of the battery pack, the assembly steps are reasonable and easy to operate, which is beneficial to improving the production efficiency and product quality of the battery pack.

The preferred embodiments of the present invention and their beneficial effects will be further described in detail in combination with specific embodiments.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but should not be construed as limiting the present invention. In the attached picture,

Fig. 1 is a partial assembly diagram of the battery pack of the present invention;

Figure 2 is a partial exploded view of the battery pack of the present invention;

Fig. 3 is the perspective view of existing rounded square tray;

Fig. 4 is a partial sectional view along line A-A in Fig. 3;

Fig. 5 is the three-dimensional view of triangular surface square pallet of the present invention;

Fig. 6 is a partial sectional view along line B-B in Fig. 5;

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

8 is an overall assembly diagram of the battery pack of 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 the battery pack of the present invention;

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

Description of reference numerals: tray 1, frame 2, support structure 3, side wall 11, bottom wall 12, positioning cavity 10, flange outer edge 13, triangular surface 14, side wall draft angle α, side wall draft angle β , Triangular surface draft angle γ, first welded wall 21, inner support wall 22, lower outer wall 23, lower support wall 24, inner wall 25, upper support wall 26, upper outer wall 27, second welded wall 28, groove 29, Lifting lugs 20, beams 31, longitudinal beams 32, liquid cooling plates 4, cooling tanks 41, liquid inlet holes 42, liquid outlet holes 43, ribs 15, bottom reinforcements 5, bottom shields 6, and top covers 7.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

Please refer to Figures 1 and 2, the present invention provides a battery pack, including a tray 1, a frame 2, a support structure 3 and batteries, the frame 2 encloses an installation space that matches the shape of the tray 1, so that the frame 2 It is fixed on the periphery of the tray 1 so that the frame 2 is against the outer surface of the side wall 11 of the tray 1 . The bottom surface of the support structure 3 is fixed on the upper surface of the bottom wall 12 of the tray 1, and the outer periphery of the support 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 Batteries.

In the battery pack provided by the present invention, a frame 2 is arranged on the outer periphery of the tray 1 to abut against the outer surface of the side wall of the tray 1, and a support structure 3 is arranged in the tray 1 to abut against the inner surface of the side wall of the tray 1 and the upper surface of the tray 1, The side wall of the tray 1 is jointly clamped by the frame 2 and the support structure 3, and the bottom wall 12 of the tray 1 is supported by the support structure 3, which improves the strength and rigidity of the battery pack, meets the demand for lightweight, and reduces the energy consumption and improved safety. The supporting structure 3 divides the loading space of the tray 1 into a plurality of positioning cavities 10 where the power supply core is placed, which can effectively protect the battery core, meet the different requirements of various extrusion, collision and bottom intrusion conditions, and further improve the battery pack. safety and reliability.

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 is enclosed by the periphery of the bottom wall 12 to form a loading space for the tray 1, and the flange outer edge 13 is enclosed by The outer periphery of the top side of the side wall 11, the side wall 11, the bottom wall 12 and the outer edge of the flange 13 are made by thermoforming stamping of steel plates. Optionally, the flange outer edge 13 fixes the tray 1 to the frame 2 by bolts, but it is not limited thereto. The flange outer edge 1 can also fix the tray 1 to the frame 2 by riveting or welding.

Since the tray 1 is manufactured by hot stamping of steel plate, it is inevitable to consider the formability of the material during the stamping process. In order to facilitate the placement of more batteries and increase the energy density of the battery system, the larger the effective volume of the tray 1 is, the better. At the same time, the tray 1 should have good formability. Using the forming analysis software to analyze the tray 1, it is found that the junction between the corner of the side wall 11 and the bottom wall 12 is most prone to cracking and wrinkling during forming. In order to ensure that the material thinning rate at each position at the junction between the corner of the side wall 11 and the bottom wall 12 can meet the design requirements when the material is formed without sacrificing the effective volume of the tray 1, the present invention proposes for the first time that the corner of the side wall 11 A triangular surface 14 is designed at the junction with the bottom wall 12, and a reasonable range is analyzed. Please refer to Fig. 3 to Fig. 6, the tray of the battery pack of the present invention has a hexagonal shape, and the hexagonal shaped tray and the square tray adopt the triangular surface design scheme to have the same technical effect. In order to facilitate comparative analysis, the square tray is taken as an example to illustrate ,details as follows:

In the present embodiment, the basic parameters of the square tray are as follows in Table 1:

Tray depth mm Flange outer edge size mm*mm Material thickness(mm) R1(mm) R2(mm) 120 1210*1746 1.0 20 15

Table 1 above shows the basic parameters of the pallet model established by the simulation analysis of the present invention. In order to compare the advantages and disadvantages of the two pallet schemes more intuitively, it is necessary to design their key parameters and carry out corresponding analysis, as follows:

The following table 2 shows the simulation analysis of the existing fillet design scheme:

serial number Side wall draft angle α° Side wall angle radius mm Effective area m^2 Maximum thinning rate% 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 following table three is the simulation analysis of the triangular surface design scheme of the present invention:

From the comparative analysis results in Table 2 and Table 3, it can be seen that:

With the rounded corner design scheme, when the side wall draft angle α is 8°, and the side wall angle radius is ≤200mm, the maximum thinning rate is greater than the threshold value of 15%. Therefore, although the effective area increases, the formability cannot meet the requirements. ; When the side wall draft angle α is 12°, the included angle radius of the side wall is 225mm, the effective area does not increase significantly, but the thinning rate is close to the critical value of 15%.

And for the triangular surface design scheme of the present invention, when the side wall draft angle β is 8°, and the triangular surface draft angle γ is 35°, the maximum thinning rate is 14.1%, which meets the design requirements, and compared with the rounded corner design scheme , the effective area has been significantly increased; and when the triangular surface draft angle γ≤30°, the effective area does not increase significantly, and the maximum thinning rate exceeds the critical value of 15%, there is a risk of molding cracking.

In addition, when the sidewall draft angle β is 12° and the triangular surface draft angle γ≥30°, the maximum thinning rate is less than the critical value of 15%, which meets the design requirements, and compared with the rounded corner design scheme, the effective area is the same There is a significant increase; and when the draft angle of the triangular surface γ≤25°, the effective area does not increase significantly, and the maximum thinning rate exceeds the critical value of 15%, and there is a risk of molding cracking.

Therefore, when defining the triangular surface design scheme, when the side wall draft angle β is 8°, the triangular surface draft angle γ ranges from 35° to 40°; when the side wall draft angle β is 12°, the triangular surface The draft angle γ ranges from 30° to 40°.

Effective area definition: the horizontal area at the bottom of the pallet, the area enclosed by the line connecting the midpoints of the arcs in the rounded area of the pallet or the midpoints of the edges of the triangles, that is, the area of the dotted rectangle in the figure is the effective area. Since the dimensions of the outer edge of the design tray 1 are the same, the depth of the tray 1 is also the same. However, the effective area of the bottom of the tray 1 corresponding to different design schemes is different, resulting in a certain difference in effective volume.

The raw material used in the steel battery pack designed by the present invention is a hot-formed steel matrix, and the matrix composition (mass percentage wt%) is C: 0.1～0.5; Si: 0.1～0.5; Mn: 0.5～2.0; P≤0.01; S≤ 0.01; Microalloying elements are added as Ti, Nb, V, Ni, Mo and other alloying elements or any combination thereof, and Ti+Nb+V+Ni+Mo≤1, and the rest are Fe and unavoidable impurities.

The thickness of the steel plate used to press the pallet 1 ranges from 0.5 to 1.5 mm, and the surface state of the steel is Al-Si coating, because the corrosion resistance of the Al-Si coating against cooling liquid is significantly better than that of other coated products or non-coated products.

The pallet preparation process is: blanking→heating→transfer→stamping→press quenching→laser cutting→finished pallet.

The thermoforming heating process is to heat at 870-950 ° C, and the holding time is 2-10 minutes. After heating, the material is transferred to the press mold, and then the stamping is carried out, and the pressure is maintained in the mold for a period of time. The holding time is 5 ~20s, the formed parts are transferred to the laser cutting machine for laser trimming. The mechanical properties of the thermoformed tray are: Rp0.2≥950MPa; Rm≥1350MPa; A80≥5%.

A triangular surface 14 is formed at the junction between the corner of the side wall 11 and the bottom wall 12 of the tray 1 of the present invention. When the draft angle β of the side wall is 8°, the range of the draft angle γ of the triangular surface is ≥ 35°; when the side wall When the draft angle β is 12°, the draft angle γ range of the triangular surface is ≥30°. In this way, the technical possibility of using hot-formed steel pallets is realized, and the contradictory relationship between the forming performance and effective volume of traditional steel pallets is resolved. Using the pallet scheme of the present invention not only ensures the high effective volume of the steel pallet, but also ensures its good formability in the stamping process. Compared with traditional aluminum alloy or mild steel materials, the use of hot-formed steel materials can greatly improve the strength of the tray, thereby enhancing the ability of the tray to resist the intrusion of foreign objects at the bottom, and improving the safety and reliability of the battery pack.

Please refer to Fig. 7. In this embodiment, the frame 2 is formed by rolling of steel plate, and the frame 2 includes a first welded wall 21, an inner support wall 22, a lower outer wall 23, a lower support Wall 24, inner wall 25, upper support wall 26, upper outer wall 27 and second welded wall 28, first welded wall 21 and the inner surface of inner wall 25 are welded and fixed, and second welded wall 28 is welded with inner support wall 22, so that the lower The outer wall 23 and the upper outer wall 2 jointly form the outer wall of the frame 2 , and the inner support wall 22 is supported between the outer wall and the inner wall 25 of the frame 2 . Optionally, grooves 29 are formed on the lower outer wall 23 and the upper outer wall 27 to further improve the structural strength and rigidity of the frame 2 . The side wall 11 of the tray 1 is against the inner wall 25 , and the flange outer edge 13 of the tray 1 is fixed on the upper supporting wall 26 . After analysis and verification, the frame 2 with a "day"-shaped cross-section structure can meet the strict extrusion and collision conditions. Under the condition of ensuring production efficiency, the requirements for the rolling die are low, and it has good strength and rigidity. The inside of the battery pack can be well protected, further improving the safety and reliability of the battery pack. As shown in FIG. 1 , in order to facilitate assembly, a plurality of lifting lugs 20 are fixed on the outer wall of the frame 2 .

Please refer to Fig. 1 and Fig. 2, in the present embodiment, support structure 3 comprises crossbeam 31 and longitudinal beam 32, and the bottom surface of crossbeam 31 and longitudinal beam 32 is all welded on the bottom wall 12 upper surface of tray 1, and crossbeam 31 and longitudinal beam 32 The two ends of each are welded to the inner surface of the side wall 11 of the tray 1, and the longitudinal beams 32 are arranged perpendicular to the beams 31, so as to divide the loading space of the tray 1 into a plurality of positioning cavities 10 for placing power supply cores. It can be understood that the supporting structure 3 is not limited to the above-mentioned structural forms, for example, the supporting structure 3 may also be arranged only with beams 31 or only with longitudinal beams 32 . Optionally, both the cross beam 31 and the longitudinal beam 32 can be pressed into a cross-section structure of "Ji" by steel plate.

Please refer to Fig. 8 and Fig. 11. In this embodiment, the battery pack of the present invention also includes a liquid cooling plate 4. The liquid cooling plate 4 is pressed into a container structure with a cooling groove 41 by steel plate. Both ends of the plate 4 and the cooling groove 41 run through the edge of the liquid cooling plate 4 to respectively form a liquid inlet hole 42 and a liquid outlet hole 43 . The liquid cooling plate 4 is sealed and welded to the lower surface of the bottom wall 12 of the tray 1. The bottom wall 12 is formed with ribs 15 corresponding to the cooling tank 41 one by one. The ribs 15 protrude downward into the cooling tank 41. The slots 41 cooperate to form passages for the coolant to flow through. The cooling liquid enters the cooling tank 41 through the liquid inlet hole 42 to cool the tray 1 and the battery cells, and then flows out from the liquid outlet hole 43 . The bottom wall 12 of the tray 1 is provided with ribs 15 corresponding to the cooling groove 41 , which improves the flatness, structural strength and rigidity of the inner side of the bottom wall 12 of the tray, thereby improving the safety and reliability of the battery pack. The ribs 15 and the cooling groove 41 are used to form a channel for the circulation of the coolant. This structure can ensure the flow rate of the coolant while increasing the heat dissipation area and improving the heat dissipation efficiency of the battery pack. It is convenient to use the existing roll welding to fulfill.

In this embodiment, the battery pack of the present invention further includes a bottom reinforcement 5 , and both ends of the bottom reinforcement 5 are fixed on the bottom surface of the frame 2 to support the liquid cooling plate 4 and the tray 1 . In this way, the bonding strength and rigidity between the frame 2 and the tray 1 can be further improved.

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 on 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, which enhances the ability of the tray to resist the intrusion of foreign objects at the bottom, and improves the safety and reliability of the battery pack.

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

The tray 1, frame 2, support structure 3, liquid cooling plate 4, bottom reinforcement 5, bottom shield 6 and top cover 7 of the battery pack of the present invention can be pressed and welded by steel plates to form a battery pack with an all-steel structure .

The present invention also provides a manufacturing method of the battery pack as follows:

Firstly, the thermoformed tray 1 stamped according to the process parameters is connected to the liquid cooling plate 4 by a roll welding process, and the tray 1 is welded to the frame 2;

Then the support structure 3 is welded in the tray 1;

Then, the bottom reinforcement 5 and the bottom shield 6 are fixed on the frame 2, and the bottom reinforcement 5 and the bottom shield 6 are welded together;

Put the heating film in the tray 1 or stick the heating film on the bottom surface of the battery cell, and then put the battery cells into the positioning cavity 10 one by one;

The top cover 7 is fixed on the frame 2 and the support structure 3 by using bolts to complete the overall assembly of the battery pack.

By adopting the manufacturing method of the battery pack, the assembly steps are reasonable and easy to operate, which is beneficial to improving the production efficiency and product quality of the battery pack.

The present invention also provides a vehicle using the above-mentioned battery pack, and the vehicle includes electric vehicles, hybrid vehicles and the like.

In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. It is not intended to indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and operate in a particular orientation, and thus should not be construed as limiting the invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying importance; the words "bottom" and "top", "inner" and "outer" respectively refer to Or away from a particular part geometry.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "communication", and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; may be mechanically connected, may also be electrically connected; may be directly communicated, may also be indirectly communicated through an intermediary, and may be internally communicated between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention Inside.

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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