WO2025000735A1 - Battery terminal and battery - Google Patents

Abstract

A battery terminal and a battery. The battery terminal comprises a pole and a sealing portion. A blind via structure is formed in the upper end surface of the pole. The blind via structure comprises a bottom portion and at least two holes which are communicated with each other. The two holes are conical holes. The diameter of the holes gradually increases from the bottom to the upper end surface of the pole. The sealing portion is arranged in the blind via structure. The sealing portion is used for sealing the blind via structure. The sealing portion at least abuts against part of the side wall of the blind via structure.

Description

Battery Terminals and Batteries Technical Field

The present application relates to the technical field of batteries, and in particular to a battery terminal and a battery.

Background Art

Lithium-ion batteries refer to batteries that contain lithium (including metallic lithium, lithium alloys, lithium ions, lithium polymers, etc.) in the electrochemical system. Lithium-ion batteries have the advantages of high energy density, good cycle performance and long service life. They are widely used in products such as electric equipment, electrical appliances and smart machines.

At present, in the existing manufacturing process of lithium-ion batteries, a pole hole is generally provided at the upper end of the battery terminal. After the battery terminal is welded to the positive/negative current collecting plate, the fluctuation of welding energy may cause poor sealing at the pole hole. Therefore, the battery terminal in the related technology is at risk of leakage.

SUMMARY OF THE INVENTION

The embodiments of the present application provide a battery terminal and a battery to solve or at least partially solve the deficiencies of the above-mentioned background technology.

The present application provides a battery terminal, comprising:

A pole, wherein the upper end surface of the pole is provided with a blind hole structure, wherein the blind hole structure comprises a bottom and at least two openings connected to each other, and the openings are all conical holes, and the aperture of the openings gradually increases from the bottom toward the upper end surface of the pole;

A sealing portion is disposed in the blind hole structure, and is used to seal the blind hole structure, and the sealing portion abuts against at least a portion of the side wall of the blind hole structure.

The present application also provides a battery, comprising a shell and the above-mentioned battery terminal, wherein the shell is provided with a pole through hole, and the pole of the battery terminal is arranged in the pole through hole.

Beneficial Effects

The beneficial effects of the present application are as follows: an embodiment of the present application provides a battery terminal and a battery, the battery terminal comprising a pole and a sealing portion, the upper end face of the pole is provided with a blind hole structure, the blind hole structure comprises a bottom, and at least two openings interconnected, and the openings are all conical holes, the aperture of the openings gradually increases from the bottom toward the upper end face of the pole, the sealing portion is arranged in the blind hole structure, the sealing portion is used to seal the blind hole structure, and the sealing portion at least abuts against part of the side wall of the blind hole structure, thereby enhancing the sealing ability of the pole and avoiding the risk of leakage of the battery terminal in the related art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a first cross-sectional view of a battery provided in an embodiment of the present application;

FIG2 is a schematic diagram of the structure of a pole provided in an embodiment of the present application;

FIG3 is a schematic diagram of a first structure of a sealing portion provided in an embodiment of the present application;

FIG. 4 is a second cross-sectional view of a battery provided in an embodiment of the present application.

FIG. 5 is a schematic diagram of a second structure of a sealing portion provided in an embodiment of the present application.

Embodiments of the present invention

In the description of this application, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, a mechanical connection or an electrical connection, a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

In the description of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

This embodiment provides a battery terminal and a battery module. They are described in detail below. It should be noted that the description order of the following embodiments is not intended to limit the preferred order of the embodiments.

Please refer to FIG. 1 , which is a first cross-sectional view of a battery provided in an embodiment of the present application.

The present embodiment provides a battery terminal and a battery, wherein the battery terminal can be used as a component of a battery 100, and is used to electrically connect the battery cell of the battery 100 with an electrical device, wherein the battery 100 includes a shell 10 and a battery terminal 1, wherein the shell 10 is provided with a pole through hole 11, and the battery terminal 1 includes a pole 20 and a sealing portion 30, wherein the pole 20 is arranged in the pole through hole 11, and the upper end surface 21 of the pole 20 is provided with a blind hole structure 20A, and the sealing portion 30 is arranged in the blind hole structure 20A, and the sealing portion 30 is used to seal the blind hole structure 20A, and the sealing portion 30 at least abuts against a part of the side wall of the blind hole structure 20A; wherein the sealing portion 30 includes but is not limited to a sealing nail structure made of aluminum material, and the blind hole structure 20A can be used as the pole hole of the pole 20, and the sealing portion 30 is fixed to the blind hole structure 20A by welding.

It should be noted that in the manufacturing process of lithium-ion batteries in the related art, the upper end of the battery terminal is generally provided with a pole hole. After the battery terminal is welded to the positive/negative collector plate, the fluctuation of welding energy may cause poor sealing at the pole hole, so the battery terminal in the related art has the risk of leakage. For example, after the battery terminal is electrically connected to the collector plate, since the connection position is connected by welding, air holes are easily generated at the connection position, which may cause certain leakage failure of the battery terminal during later use.

It can be understood that, in this embodiment, the sealing portion 30 is arranged in the blind hole structure 20A, and the sealing portion 30 is used to seal the blind hole structure 20A, and the sealing portion 30 at least abuts against a portion of the side wall of the blind hole structure 20A, thereby improving the sealing ability of the pole 20 and avoiding the risk of leakage in the battery terminal 1 in the related art.

In addition, since the present embodiment uses a sealing portion 30 such as a sealing nail structure to perform hole plugging welding in the blind hole structure 20A, laser welding can be performed on the sealing portion 30 when performing external Pack assembly welding, thereby avoiding the situation in which when welding on the pole 20, the laser heat affects the lower plastic at the bottom of the pole 20 due to the lower plastic pressing down on the pole 20, thereby causing insulation failure and leakage.

In one of the embodiments, please refer to Figure 1 and Figure 2, wherein Figure 2 is a schematic diagram of the structure of the pole provided in the embodiment of the present application; the blind hole structure 20A includes a bottom 22 and at least two openings 2 that are interconnected, and the openings 2 are all conical holes, and the aperture of the opening 2 gradually increases from the bottom 22 toward the upper end surface 21 of the pole 20, thereby making the installation and disassembly of the sealing portion 30 simple and quick, and optimizing the production process.

Furthermore, the blind hole structure 20A includes a first opening 21A and a second opening 21B, the second opening 21B is located on a side of the first opening 21A away from the bottom 22, the minimum diameter L3 of the second opening 21B is equal to the maximum diameter L1 of the first opening 21A, and the sealing portion 30 abuts against at least part of the side wall of the second opening 21B, thereby avoiding the problem of sealing failure caused by the sealing portion 30 being easily fallen off or offset during the production process of assembly and transportation in the related art, and reducing the probability of the sealing portion 30 being deflected during welding, thereby improving the sealing performance.

In one embodiment, the maximum diameter L1 of the first opening 21A and/or the minimum diameter L3 of the second opening 21B are greater than or equal to 5 mm and less than or equal to 10 mm; and/or the minimum diameter L2 of the first opening 21A is greater than or equal to 3 mm and less than or equal to 8 mm; and/or the maximum diameter L4 of the second opening 21B is greater than or equal to 8 mm and less than or equal to 13 mm, wherein the minimum diameter of the first opening 21A is the diameter of the bottom 22 of the blind hole structure 20A, thereby forming the first opening 21A and the second opening 21B that are interconnected on the pole 20; the blind hole structure 20A has a simple manufacturing process, and the first opening 21A and the second opening 21B can be integrally formed, thereby reducing production costs; and the set diameter range can adapt to the size of the pole 20, while ensuring the current carrying capacity of the pole, improving the insulation performance.

Further, the first opening 21A has a first side wall 22A, and the angle between the first side wall 22A and the bottom 22 in the vertical direction is a first preset angle α, and the first preset angle α is greater than or equal to 40 degrees and less than or equal to 80 degrees; the second opening 21B has a second side wall 22B, and the angle between the second side wall 22B and the bottom 22 in the vertical direction is a second preset angle β, and the second preset angle β is greater than 0 degrees and less than or equal to 18 degrees; and/or, the spacing H1 between the junction of the first side wall 22A and the second side wall 22B and the bottom 22 is 3 mm to 5 mm, so that when the battery terminal 1 is in the assembly and transportation process, the sealing portion 30 and the blind hole structure 20A are not easy to shake, thereby making the subsequent welding between the sealing portion 30 and the blind hole structure 20A firm and reliable, thereby improving the sealing of the battery terminal 1.

In this embodiment, the maximum diameter L1 of the first opening 21A is preferably in the range of 6 mm to 8 mm, the minimum diameter L1 of the first opening 21A is preferably in the range of 4 mm to 6 mm, the maximum diameter L4 of the second opening 21B is preferably in the range of 9 mm to 11 mm, the minimum diameter L3 of the second opening 21B is equal to the maximum diameter L1 of the first opening 21A, the first preset angle α is preferably 45 degrees to 65 degrees, the second preset angle β is preferably 5 degrees to 15 degrees, the first preset angle α is greater than the second preset angle β, and the spacing H1 between the junction of the first side wall 22A and the second side wall 22B and the bottom 22 is preferably 3 mm to 4 mm, so that The first opening 21A and the second opening 21B are formed on the pole 20 and are connected to each other, wherein the sealing portion 30 abuts against at least part of the side wall of the second opening 21B, and the side of the second side wall 22B close to the sealing portion 30 is an inclined surface, and the force exerted by the second side wall 22B on the sealing portion 30 can be decomposed into a first force F1 along the first direction X and a second force F2 along the second direction Y. The sealing portion 30 is limited by the first force F1 and the second force F2 at the same time, thereby enhancing the sealing effect of the pole 20 and reducing the problem of sealing failure caused by the sealing portion 30 being easy to fall off or deviate during assembly and transportation in the related art.

It should be noted that, as shown in FIG. 1 , this embodiment takes an example where X indicates the first direction, Y indicates the second direction, and the first direction X and the second direction Y are perpendicular to each other to illustrate the technical solution of the present application.

Further, please refer to FIG. 1 and FIG. 3 , wherein FIG. 3 is a schematic diagram of the first structure of the sealing portion provided in an embodiment of the present application.

In this embodiment, the sealing portion 30 includes a first sealing sub-portion 31 and a second sealing sub-portion 32, the second sealing sub-portion 32 is connected to the side of the first sealing sub-portion 31 away from the bottom 22, and the second sealing sub-portion 32 is used to seal the second opening 21B; the surface of the second sealing sub-portion 32 close to the second side wall 22B is an inclined surface, and the side of the second sealing sub-portion 32 close to the second side wall 22B is in contact with the second side wall 22B, and the surface of the second sealing sub-portion 32 close to the second side wall 22B and the bottom 22 in the vertical direction form a third preset angle γ, and the size of the third preset angle γ is equal to the size of the second preset angle β, so that the second sealing sub-portion 32 is completely in contact with the second side wall 22B of the second opening 21B, thereby enhancing the sealing effect of the pole 20 and thereby reducing the risk of sealing failure caused by the falling off of the sealing portion 30.

Further, in the present embodiment, the forming method of the sealing portion 30 includes but is not limited to one of stamping forming or upsetting forming, and the first sealing sub-portion 31 and the second sealing sub-portion 32 are of an integrally formed design, which has simple loading and unloading operations, a firm structure, and very low cost; wherein, the first sealing sub-portion 31 is spaced apart from the first side wall 22A, and the surface of the first sealing sub-portion 31 close to the first side wall 22A is an inclined surface; the surface of the first sealing sub-portion 31 close to the first side wall 22A and the angle in the vertical direction of the bottom 22 are a fourth preset angle g, and the fourth preset angle g is greater than or equal to 30 degrees and less than or equal to 60 degrees; it can be understood that in the present embodiment, by arranging the first sealing sub-portion 31 to be spaced apart from the first side wall 22A, when the blind hole structure 20A is sealed by the sealing portion 30, the first sealing sub-portion 31 can guide the second sealing sub-portion 32, so that the installation and disassembly of the sealing portion 30 becomes simple and quick, the production process is optimized, and the equipment addition is reduced.

Specifically, in this embodiment, a diameter range L5 of the first sealing sub-portion 31 away from the second sealing sub-portion 32 is greater than or equal to 3 mm and less than or equal to 8 mm, a diameter L6 of the second sealing sub-portion 32 away from the first sealing sub-portion 31 is equal to a maximum diameter L4 of the second opening 21B, a diameter of the second sealing sub-portion 32 close to the first sealing sub-portion 31 is equal to a diameter of the first sealing sub-portion 31 close to the second sealing sub-portion 32, and a distance H3 between the junction of the first sealing sub-portion 31 and the second sealing sub-portion 32 and the side of the second sealing sub-portion 32 away from the first sealing sub-portion 31 is greater than or equal to 1 mm and less than or equal to 5 mm.

Further, in one of the embodiments, please refer to Figures 1 and 2, the pole 20 is provided with a groove 20B, the shell 10 is clamped in the groove 20B, and the groove 20B is insulated from the shell 10 by a sealing ring 50, the battery also includes a limiter 40, the pole 20 is formed with an upper end 210, a connecting part 220 and a lower end 230 connected in sequence through the groove 20B, the limiter 40 is arranged on the outer periphery of the connecting part 220 and is located between the sealing ring 50 and the lower end 230, so as to prevent the sealing ring 50 from shaking when the shell 10 is clamped in the groove 20B, thereby avoiding the occurrence of a short circuit and achieving reliable sealing.

Specifically, in this embodiment, the sealing ring 50 includes a first sealing ring 51 and a second sealing ring 52, the first sealing ring 51 is located between the shell 10 and the upper end 210 and is at least partially disposed between the shell 10 and the connecting portion 220, and the second sealing ring 52 is located between the shell 10 and the limit member 40 and is at least partially disposed between the shell 10 and the connecting portion 220, thereby isolating the shell 10 from the pole 20 to avoid a short circuit caused by contact between the two.

Preferably, the first sealing ring 51 is provided with a first return hook structure 51A, and the first return hook structure 51A is located between the shell 10 and the bottom 22 of the groove 20B. The second sealing ring 52 is provided with a second return hook structure 52A, and the second return hook structure 52A is located between the shell 10 and the bottom 22 of the groove 20B. The first return hook structure 51A and the second return hook structure 52A abut against each other, thereby wrapping the side of the shell 10 close to the groove 20B, so that the first sealing ring 51 and the second sealing ring 52 can be more tightly sealed, thereby improving the sealing effect.

It can be understood that, in this embodiment, the battery can be applied to electrical equipment in various fields such as automobiles, aircraft, and mechanical production equipment to provide electrical energy for the electrical equipment, and has strong practicality.

In one of the embodiments, in combination with FIG. 3 and FIG. 4 , FIG. 3 is a second cross-sectional view of the battery provided in the embodiment of the present application, and FIG. 4 is a second structural schematic diagram of the sealing portion provided in the embodiment of the present application.

In this embodiment, the structure of the battery is similar to/the same as that of the battery provided in the above embodiment. Please refer to the description of the battery in the above embodiment for details, which will not be repeated here. The difference between the two is only that:

In this embodiment, in a direction perpendicular to the bottom 22 , the height of the highest point of the sealing portion 30 is greater than or equal to the height of the upper end surface 21 of the pole 20 ; preferably, the height of the highest point of the sealing portion 30 is greater than the height of the upper end surface 21 of the pole 20 .

It should be noted that when the battery terminal 1 is being welded for external Pack assembly, for example, when the pole 20 is welded and fixed to the busbar in the related art, fluctuations in welding energy can easily damage the pole 20, thereby causing insulation failure and leakage.

It can be understood that, in this embodiment, the sealing portion 30 is arranged in the blind hole structure 20A, and the height of the highest point of the sealing portion 30 is greater than the height of the upper end surface 21 of the pole 20. The sealing portion 30 can serve as one end of the battery terminal 1 connected to the busbar, thereby ensuring the sealing and insulation of the battery terminal 1 during the Pack assembly process.

Specifically, the sealing portion 30 includes a positioning portion 34 and a main body portion 33, the positioning portion 34 is located on the side of the main body portion 33 away from the bottom 22, the side of the main body portion 33 close to the second opening 21B is in contact with the side wall of the second opening 21B, and the side of the main body portion 33 away from the bottom 22 is flush with the upper end surface 21 of the pole 20; by providing the positioning portion 34, when the battery terminal 1 is being assembled and welded in an external Pack, the positioning portion 34 can be used as a connection between the battery terminal 1 and the busbar. One end, thereby ensuring the sealing and insulation of the battery terminal 1 during the Pack assembly process, avoiding the phenomenon that when welding on the pole 20, a large amount of heat will be generated during welding, which will cause the pole 20 to have cracks or slight deformation, and then insulation failure and leakage will occur; and, by arranging the positioning portion 34 to be located on the side of the main body 33 away from the bottom 22, it is also possible to avoid that after the sealing portion 30 is welded, welding slag is attached to the upper end surface 21 of the pole 20, thereby affecting the subsequent welding of the battery terminal 1.

Further, in the present embodiment, the ratio of the length of the orthogonal projection of the positioning portion 34 on the main body 33 to the length of the main body 33 on the side close to the upper end surface 21 of the pole 20 is in the range of 7% to 76%; and/or, the height range of the positioning portion 34 is greater than 0 mm and less than or equal to 0.3 mm; wherein, the ratio of the length of the orthogonal projection of the positioning portion 34 on the main body 33 to the length of the main body 33 on the side close to the second opening 21B is preferably 50% to 60%, and the height range of the positioning portion 34 is preferably 0.1 mm to 0.2 mm, so that when the battery terminal 1 is subjected to external Pack assembly welding, the contact area between the positioning portion 34 and the busbar is increased, and the welding strength between the positioning portion 34 and the busbar is correspondingly improved, thereby improving reliability.

In this embodiment, the main body 33 is spaced apart from the bottom 22, and the spacing H4 between the side of the main body 33 close to the bottom 22 and the bottom 22 is greater than or equal to 0.2 mm and less than or equal to 0.5 mm; the spacing H4 between the side of the main body 33 close to the bottom 22 and the bottom 22 is preferably 0.2 mm to 0.3 mm. By arranging the main body 33 and the bottom 22 to be spaced apart, a closed space is provided between the bottom 22 and the sealing portion 30, which is used as a storage portion when leakage occurs at the blind hole structure 20A, thereby improving the service life and safety of the battery terminal 1.

Furthermore, this embodiment provides an electrical device, which includes the battery described in any of the above embodiments, and the battery module is used as a power supply for the electrical device. Therefore, the electrical device also has the advantages of the above battery module, which helps to simplify the overall structure of the electrical device; wherein the electrical device can be a car, an aircraft, a mechanical production equipment, etc.

Claims (20)

A battery terminal, comprising: A pole, wherein the upper end surface of the pole is provided with a blind hole structure, wherein the blind hole structure comprises a bottom and at least two openings connected to each other, and the openings are all conical holes, and the aperture of the openings gradually increases from the bottom toward the upper end surface of the pole; A sealing portion is disposed in the blind hole structure, and is used to seal the blind hole structure, and the sealing portion abuts against at least a portion of the side wall of the blind hole structure. The battery terminal according to claim 1, wherein the blind hole structure comprises a first opening and a second opening, the second opening is located on a side of the first opening away from the bottom, the minimum diameter of the second opening is equal to the maximum diameter of the first opening, and the sealing portion abuts against at least a portion of the side wall of the second opening. The battery terminal according to claim 2, wherein the maximum diameter range of the first opening and/or the minimum diameter range of the second opening is greater than or equal to 5 mm and less than or equal to 10 mm; And/or, the minimum diameter of the first opening is greater than or equal to 3 mm and less than or equal to 8 mm; And/or, the maximum diameter of the second opening is greater than or equal to 8 mm and less than or equal to 13 mm. The battery terminal according to claim 2, wherein the first opening has a first side wall, and the angle between the first side wall and the bottom in a vertical direction is a first preset angle, and the first preset angle is greater than or equal to 40 degrees and less than or equal to 80 degrees; The second opening has a second side wall, and the angle between the second side wall and the bottom in a vertical direction is a second preset angle, and the second preset angle is greater than 0 degrees and less than or equal to 18 degrees; And/or, the distance between the junction of the first side wall and the second side wall and the bottom is greater than or equal to 3 mm and less than or equal to 5 mm. The battery terminal according to claim 3, wherein the sealing portion comprises a first sealing sub-portion and a second sealing sub-portion, the second sealing sub-portion is connected to a side of the first sealing sub-portion away from the bottom, and the second sealing sub-portion is used to seal the second opening; The surface of the second sealing sub-portion close to the second side wall is a slope, and the side of the second sealing sub-portion close to the second side wall abuts against the second side wall. The angle between the surface of the second sealing sub-portion close to the second side wall and the bottom in the vertical direction is a third preset angle, and the size of the third preset angle is equal to the size of the second preset angle. The battery terminal according to claim 5, wherein the first sealing sub-portion is spaced apart from the first side wall, and a surface of the first sealing sub-portion close to the first side wall is an inclined surface; An angle between a surface of the first sealing sub-portion close to the first side wall and the bottom in a vertical direction forms a fourth preset angle, and the fourth preset angle is greater than or equal to 30 degrees and less than or equal to 60 degrees. The battery terminal according to claim 5, wherein the diameter range of the first sealing sub-portion away from the second sealing sub-portion is greater than or equal to 3 mm and less than or equal to 8 mm. The battery terminal according to claim 5, wherein the diameter of the second sealing sub-portion away from the first sealing sub-portion is equal to the maximum diameter of the second opening, and the diameter of the second sealing sub-portion close to the first sealing sub-portion is equal to the diameter of the first sealing sub-portion close to the second sealing sub-portion. The battery terminal according to claim 5, wherein the distance between the intersection of the first sealing sub-portion and the second sealing sub-portion and the side of the second sealing sub-portion away from the first sealing sub-portion is greater than or equal to 1 mm and less than or equal to 5 mm. The battery terminal according to claim 5, wherein the first sealing sub-portion and the second sealing sub-portion are integrally formed. The battery terminal according to any one of claims 1 to 10, wherein, in a direction perpendicular to the bottom, the height of the highest point of the sealing portion is greater than or equal to the height of the upper end surface of the pole. The battery terminal according to claim 11, wherein the sealing portion includes a positioning portion and a main body portion, the positioning portion is located on a side of the main body portion away from the bottom, a side of the main body portion close to the second opening abuts against a side wall of the second opening, and a side of the main body portion away from the bottom is flush with an upper end surface of the pole. The battery terminal according to claim 12, wherein the ratio of the length of the positive projection of the positioning portion on the main body to the length of the main body on the side close to the upper end surface of the pole is in the range of 7% to 76%; And/or, the height range of the positioning portion is greater than 0 mm and less than or equal to 0.3 mm. The battery terminal according to claim 12, wherein the main body portion is spaced apart from the bottom portion. The battery terminal according to claim 14, wherein a spacing range between a side of the main body portion close to the bottom and the bottom is greater than or equal to 0.2 mm and less than or equal to 0.5 mm. A battery, comprising a shell and a battery terminal as claimed in any one of claims 1 to 15, wherein the shell is provided with a pole through hole, and the pole of the battery terminal is arranged in the pole through hole. The battery according to claim 16, wherein the pole ring is provided with a groove, the shell is clamped in the groove, and the groove is insulated from the shell by a sealing ring. The battery according to claim 17, wherein the battery further comprises a limiter, the pole is formed with an upper end, a connecting portion and a lower end connected in sequence through the groove, and the limiter is arranged on the outer periphery of the connecting portion and is located between the sealing ring and the lower end. The battery according to claim 18, wherein the sealing ring includes a first sealing ring and a second sealing ring, the first sealing ring is located between the shell and the upper end portion and is at least partially disposed between the shell and the connecting portion, and the second sealing ring is located between the shell and the limit member and is at least partially disposed between the shell and the connecting portion. The battery according to claim 19, wherein the first sealing ring is provided with a first hook structure, the first hook structure is located between the shell and the bottom of the groove, the second sealing ring is provided with a second hook structure, the second hook structure is located between the shell and the bottom of the groove, and the first hook structure and the second hook structure abut against each other.