Explosion-proof battery cover plate assembly

Abstract

An explosion-proof battery cover plate assembly. A protection assembly (5) is provided on an electrolyte injection hole (2), such that the protection assembly (5) wraps around the outer wall of the electrolyte injection hole (2) and forms a vertically-penetrating through hole in the middle for injection of a battery electrolyte; the protection assembly (5) has a structure with a closed bottom and a flow channel (501) formed at the periphery; the lower surface of a cover plate (1) is covered with a plastic protective layer (6) to form a cover over the lower surface of the cover plate (1), such that the cover plate (1) is isolated from the battery electrolyte inside a battery box by means of the plastic protective layer (6). The present device uses the protection assembly (5) arranged inside the electrolyte injection hole (2); during electrolyte injection, the battery electrolyte flows into a cavity of the battery box through the flow channel (501) formed on the side of the protection assembly (5), without directly impacting a battery electrode sheet located in the battery box, thereby providing protection for the battery electrode sheet, prolonging the actual service life of a battery; and the protection assembly (5) can provide an effective seal in combination with a plug nail for sealing, and when expansion occurs in the battery, the protection assembly (5) can serve as an explosion-proof valve for pressure relief effects.

Description

An explosion-proof battery cover assembly Technical Field

[0001] The present invention belongs to the technical field of battery equipment, and in particular relates to an explosion-proof battery cover assembly. Background Art

[0002] New energy electric vehicles are currently widely used. They use safer and more environmentally friendly electricity. Therefore, in actual use, the stored chemical energy can be stably converted into kinetic energy for driving the vehicle.

[0003] However, since the battery body uses the mutual conversion of electrical energy and chemical energy, in actual use, once there is incomplete conversion or defects in the energy conversion process, it will cause the chemical energy in the battery itself to undergo violent chemical reactions. Therefore, in order to ensure the safety of the battery, a pressure relief valve is usually provided in the battery body. When a violent chemical reaction occurs in the battery body, chemical substances will be ejected from the position of the pressure relief valve to reduce the damage to the battery body.

[0004] Chinese patent application publication number CN114583344 A discloses a battery cover and battery, relating to the field of new energy technology. The battery cover includes a battery cover body, which is an injection-molded cover. A pole for connecting to a pole piece is provided on the battery cover body. A liquid injection hole and an explosion-proof valve are also provided on the battery cover body. The battery cover body in this patent is made of plastic. While plastic has certain insulating properties, its mechanical strength and corrosion resistance are relatively weak. In actual use, once subjected to external impact, it will severely deform, and may even cause leakage of chemical substances within the battery, posing a greater risk.

[0005] Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an explosion-proof battery cover assembly to solve the above-mentioned technical problems in the prior art.

[0007] The purpose of the present invention can be achieved through the following technical solutions:

[0008] An explosion-proof battery cover assembly includes a cover body, a liquid injection hole, an explosion-proof valve installation hole, and an electrode column through hole opened on the cover body.

[0009] A protective component is provided on the injection hole, so that the protective component wraps around the outer wall where the injection hole is located and forms a through hole running vertically through the middle portion for injecting battery liquid. The protective component has a closed bottom and a flow channel structure opened at the periphery, so that when the battery liquid is injected, the battery liquid flows into the cavity of the battery box through the flow channel on the side;

[0010] An explosion-proof disc is provided on the explosion-proof valve installation hole;

[0011] The electrode column through-holes are provided in two groups, and are provided with a positive electrode column assembly and a negative electrode column assembly respectively, and are connected to the electrode sheet inside the battery box;

[0012] The lower surface of the cover body is covered with a plastic protective layer, so that the cover body and the interior of the battery box are isolated from each other by the plastic protective layer.

[0013] Furthermore, the injection holes are provided in one or two groups on the upper surface of the cover body, and are located at the edge boss position of the through hole where the injection holes are located, and are arranged as an inclined slope structure that is narrow at the top and wide at the bottom;

[0014] The lower surface where the boss structure is located protrudes from the lower surface where the cover plate body is located.

[0015] Furthermore, the protection component is made of EPDM or TPV material.

[0016] Furthermore, the boss extending toward the center of the injection hole allows the protection component to fully wrap the boss inside the injection hole during injection molding, and form a through hole for injection in the middle.

[0017] Furthermore, the protection component and the plastic protective layer are made of the same material and are an integral injection-molded structure.

[0018] Furthermore, the protection component and the plastic protective layer are independently processed and formed, and a first connecting hole is provided below the plastic protective layer where the protection component is located, so that liquid can flow through the first connecting hole when the liquid is injected through the injection hole where the protection component is located.

[0019] Furthermore, when the battery box explodes, the protective component is separated from the arrangement on the injection hole to quickly release the chemical reaction pressure in the battery box.

[0020] Furthermore, a second communication hole is provided in the plastic protective layer area below the explosion-proof valve installation hole, and the interior of the battery box covered by the cover body is connected through the second communication hole.

[0021] Furthermore, the positive electrode post assembly includes a positive terminal and a positive electrode welding sheet, which is fixed to the electrode post through-hole through the positive electrode welding sheet, and the positive terminal is fixed to the positive electrode welding sheet, and the positive terminal is simultaneously connected to the electrode sheet inside the battery box;

[0022] At the same time, the negative electrode pole assembly is composed of the same structural parts as the positive electrode pole assembly.

[0023] Furthermore, a plurality of positioning grooves are provided on the outer edge of the cover plate body where the electrode pole through-hole is located. The positioning grooves are radially opened outward from the center of the electrode pole through-hole, and the welding piece is fixedly welded to the positioning grooves.

[0024] Beneficial effects of the present invention:

[0025] 1. A protective component is set inside the injection hole used in this device to protect the inner wall of the injection hole and reduce the erosion of the battery liquid. At the same time, when injecting liquid, the battery liquid can flow into the cavity of the battery box through the flow channel opened on the side, and will not directly impact the end of the battery electrode located in the battery box. Therefore, it can protect the battery electrode and improve the actual service life of the battery.

[0026] 2. The protective component and the sealing pin used in the liquid injection hole of this device can be effectively combined and sealed. When chemical reaction and expansion occur inside the battery, the pin on the protective component can be quickly ejected as an explosion-proof valve to release pressure in time, thereby improving the safety of the battery.

[0027] 3. The liquid injection hole used in this device is integrally formed with the plastic protective layer located under the cover body. It is directly injection molded on the cover body, which reduces the process of separate molding and then secondary assembly, and improves the efficiency and cost expenditure of product molding.

[0028] 4. The protective component used in this device and the plastic protective layer located under the cover body are separately molded. During the secondary assembly, when the battery liquid in the battery box undergoes a violent chemical reaction, the protective component body can also pop out from the position of the liquid injection hole, acting as a pressure relief valve, greatly improving the rapid pressure relief when the expansion reaction occurs inside the battery, and improving the safety of battery use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments or the prior art.

[0030] FIG1 is a schematic diagram of the overall structure of a battery cover assembly with a single injection hole according to an embodiment of the present invention;

[0031] FIG2 is a schematic diagram of the front structure of the cover plate body according to an embodiment of the present invention;

[0032] FIG3 is a schematic structural diagram of the back side of the cover plate body according to an embodiment of the present invention;

[0033] FIG4 is a schematic diagram of the structure of a protection component according to an embodiment of the present invention;

[0034] FIG5 is a schematic diagram of the structure of a plastic protective layer according to an embodiment of the present invention;

[0035] FIG6 is a schematic diagram of the overall structure of a battery cover assembly with dual injection holes according to an embodiment of the present invention;

[0036] 7 is a schematic diagram of the overall cross-sectional structure of a single injection hole in a simultaneous molding state according to an embodiment of the present invention;

[0037] FIG8 is a schematic diagram of the structure of part A in FIG7 according to an embodiment of the present invention;

[0038] 9 is a schematic diagram of the overall cross-sectional structure of the dual injection holes in the simultaneous molding state according to an embodiment of the present invention;

[0039] 10 is a schematic diagram of the overall cross-sectional structure of a single injection hole in a split molding state according to an embodiment of the present invention;

[0040] 11 is a schematic diagram of the overall cross-sectional structure of the double injection holes in the split molding state according to an embodiment of the present invention;

[0041] 12 is a schematic diagram of the back structure of a battery cover assembly with a single injection hole in a simultaneous molding state according to an embodiment of the present invention;

[0042] 13 is a schematic diagram of the back structure of a battery cover assembly with dual injection holes in a split-molded state according to an embodiment of the present invention;

[0043] 14 is a schematic diagram of the molding process of a battery cover assembly with a single injection hole in a split molding state according to an embodiment of the present invention;

[0044] FIG15 is a schematic diagram of the explosion structure of the explosion-proof battery cover assembly according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] As shown in Figures 1, 2, 3 and 15, an embodiment of the present invention provides an explosion-proof battery cover assembly, including a cover body 1 (generally made of a harder metal material, and this application uses a high-strength aluminum plate, which can provide a certain protective function), an injection hole 2, an explosion-proof valve mounting hole 3, and an electrode pole through-hole 4 are opened on the cover body 1; a protective component 5 is provided on the injection hole 2, and the lower surface of the cover body 1 is covered with a plastic protective layer 6.

[0047] A protective assembly 5 is provided over the liquid injection port 2. This protective assembly 5 is made of EPDM or TPV, a material with a certain degree of elasticity and corrosion resistance, allowing for long-term storage in conjunction with the liquid injection port 2. Due to its small size, the protective assembly 5 can be individually processed during actual use, enabling the production of multiple parts using a single mold, followed by assembly and subsequent assembly, thereby improving production efficiency.

[0048] The protective component 5 is wrapped around the outer wall where the injection hole 2 is located and a through hole is formed in the middle that passes through the upper and lower parts (this through hole is used for the injection of battery liquid to reduce the erosion of the side wall of the injection hole 2 caused by the battery liquid during injection). As shown in FIG4 , the protective component 5 has a closed bottom and a flow channel 501 structure opened at the periphery (at this time, the outer diameter of the structure at the bottom of the protective component 5 is larger than the actual inner diameter of the injection hole 2, which can play a good protective role and prevent it from accidentally falling off or being easily pulled out). When the battery liquid is injected, the battery liquid flows into the cavity of the battery box from the side flow channel 501. Since the battery box flows in a vertical direction, in the traditional battery box, the position below the injection hole 2 is located. Each time the injection operation is performed, the impact of the battery liquid will be on the position directly below the injection hole 2. The battery electrode at the right side causes corrosion to the battery electrode, and this corrosion is different from the battery electrode at the adjacent position (this battery liquid itself is highly corrosive. When placed normally, the corrosion degree of adjacent battery electrodes is the same, so there will not be a large potential difference). When the battery electrode located below the injection hole 2 is injected for a long time, this battery liquid is under the impact of a large water flow pressure. Especially now, in order to improve the storage capacity of the battery, its volume is getting larger and larger. Therefore, during processing, the amount of battery liquid injected increases, but the diameter of the injection hole 2 does not increase. Therefore, a longer injection time is required, which can easily cause corrosion at the upper part of the electrode, affecting the actual output potential difference of the battery, and there are also safety hazards in the storage of this battery liquid.

[0049] Therefore, as shown in Figure 8, in the present application, a protective component 5 is provided at the position of the injection hole 2. With this structure, when the battery liquid is injected, even if the pressure is high, the bottom of the protective component 5 is a closed structure, and will not directly impact the battery pole piece located below the injection hole 2 in the battery box, thereby ensuring the safety of the battery pole piece and the overall battery service life. In addition, the flow channel 501 provided at the bottom side of the protective component 5 can disperse the injected battery liquid into the interior of the battery box, thereby avoiding direct impact on the upper part of the battery pole piece and causing unnecessary corrosion.

[0050] As needed, the injection hole 2 extends toward the center hole and forms a boss structure (at this time, there is still a through hole in the middle part surrounded by the boss for injecting liquid, which is a non-closed structure). At this time, the cross-section of the upper surface where the boss is located is a trapezoidal inclined structure, and the lower surface where the boss structure is located protrudes from the lower surface where the cover body 1 is located. Therefore, when the protective component 5 is injection molded, it can be firmly connected to the structure at this position of the injection hole 2 to avoid falling off easily from this position.

[0051] The outer wall where the protection component 5 is located forms a boss that fully wraps the injection hole 2, and a through hole is formed in the middle that passes through it from top to bottom (the upper surface of this boss is lower than the upper plane where the cover body 1 is located. Therefore, when the protection component 5 is injection molded, the upper surface where the protection component 5 is located is flush with the upper surface of the cover body 1. At this time, the thickness formed by the protection component 5 makes up for the depth of the boss sinking. This boss located at the injection hole 2 can be formed by stamping or directly cast), thereby realizing the assembly molding of the protection component 5 and the injection hole 2, making the protection component 5 an integrated injection molding structure. This injection molding method can achieve a firm locking of the protection component 5 and the inner wall of the injection hole 2, and there is no need to use the process of separately molding the protection component 5 and then performing a secondary assembly, thereby improving the molding efficiency.

[0052] After the protective component 5 located on the injection hole 2 is formed, the middle opening position of the protective component 5 is blocked by a pin made of the same material. Compared with the traditional direct molding of the injection hole 2, a direct sealed connection between the pin and the protective component 5 can be achieved. At this time, the two materials use the same plastic material and have a certain elasticity (due to the different materials of the injection hole 2, the traditional injection hole 2 is prone to leakage when connected to the pin), and when high temperature occurs, the traditional pin is easily affected by high temperature carbonization and is difficult to detach from the opening position of the injection hole 2. However, in this application, since the protective component 5 and the pin are softly connected, when subjected to high temperature, the pin can be quickly ejected from the through-hole position of the protective component 5, and therefore, it can also play a good role in pressure relief.

[0053] At this time, the injection holes 2 are arranged in one group or two groups as needed, specifically referring to Figures 7 and 12. For a small-volume battery box, one group of injection holes 2 can be used; when two groups are used (specifically as shown in Figure 9), the battery box generally used is larger in volume (more battery liquid needs to be injected, and when one group of injection holes 2 is used for injection, the injection time will be longer. At the same time, the exposed injection holes 2 without any protection will directly contact the battery liquid junction, and will also cause a certain degree of deformation of the edges of the injection holes 2, affecting the airtightness when the cap is sealed at the position where the injection holes 2 are located). Therefore, two groups of injection holes 2 can be used for simultaneous injection to improve the injection efficiency.

[0054] At this time, the protective component 5 and the plastic protective layer 6 are made of the same material (EPDM or TPV material) and are an integrated injection molding structure. This method can realize the direct molding of the plastic protective layer 6 without the need for secondary assembly, saving process operations. This plastic protective layer 6 can reduce the direct contact between the cover body 1 and the liquid in the battery box.

[0055] The protective component 5 and the plastic protective layer 6 can also be independently processed and formed (formed separately using different materials), and then assembled on the cover body 1. The specific assembly process can be shown in Figure 14, and a first connecting hole 601 (as shown in Figure 5) is opened below the plastic protective layer 6 where the protective component 5 is located, so that when the liquid is injected through the injection hole 2 where the protective component 5 is located, it flows through the first connecting hole 601 (this first connecting hole 601 is a convex structure, and forms a cover for the bottom of the protective component 5, and there is a certain gap between the bottom and side walls of the protective component 5, which is convenient for assembly and further protects the protective component 5). When this structural design is adopted, once the interior of the battery box expands, the explosion-proof disk 31 provided on the explosion-proof valve mounting hole 3 is first ejected (when the pressure in the battery box reaches 0.4-0.8MPa, that is, at this time, the explosion-proof disk 31 is ejected from the position where the explosion-proof valve mounting hole 3 is located).

[0056] Compared with the existing technology, after the explosion-proof plate is integrally formed (that is, the position where the explosion-proof plate is located is integrally formed with the cover plate), it is also necessary to perform a knife pressing process on the upper surface of the explosion-proof plate (that is, embossing is formed on the surface of the explosion-proof plate. When the battery expands, the embossing on the explosion-proof plate will crack, thereby achieving the effect of rupture and pressure relief of the explosion-proof plate). Once the force of the knife pressing on the explosion-proof plate is insufficient, or the knife pressing is frustrated during a long period of pressing, the explosion-proof plate 31 will not be able to effectively burst when it reaches the specified pressure, affecting the safe pressure relief of the explosion-proof plate.

[0057] As shown in Figure 15, during assembly, an explosion-proof valve 301 is provided at the inner edge of the explosion-proof valve mounting hole 3, and the welding end of the explosion-proof valve 301 is set at the arc position of the explosion-proof valve 301. The advantage of this design is that the explosion-proof plate 31 can be processed and formed separately (no secondary pressing process for the explosion-proof plate 31 is required, which improves the processing efficiency and reduces the cost), and its thickness and morphology can be better controlled. Therefore, the explosion-proof plate 31 in this application has a good explosion-proof effect, and the explosion-proof valve bursting pressure value is 0.6±0.20MPa. Before the explosion, the explosion-proof plate 31 and its weld are leak-proof. When the pressure increases further, the protective component 5 located on the injection hole 2 will pop out under the action of the internal pressure and detach from the injection hole 2 (the injection hole 2 is twice as large as the traditional battery box injection hole, which can facilitate the molding of the side wall of the protective component 5, and the through hole for injection is formed in the middle of the formed protective component 5). Therefore, the injection hole 2 at this time can be used as a pressure relief port, and cooperated with the explosion-proof valve mounting hole 3 on the cover body 1 to discharge the chemical substances in the battery box to the greatest extent and reduce the occurrence of secondary damage.

[0058] Of course, as needed, one or two groups of injection holes 2 are opened on the upper surface of the cover body 1. When one group of injection holes 2 is used, as shown in Figure 10, when two groups are used (as shown in Figures 6, 11, and 13), the battery box generally used is larger in volume (more battery liquid needs to be injected. When one group of injection holes 2 is used for injection, the injection time will be longer. At the same time, the exposed injection holes 2 without any protection will directly contact the battery liquid junction, which will also cause a certain degree of deformation of the edge of the injection hole 2, affecting the airtightness when the cover is sealed at the position where the injection holes 2 are located). Therefore, two groups of injection holes 2 can be used to inject liquid at the same time to improve the injection efficiency. Of course, when explosion protection occurs, the protection components 5 located on the two groups of injection holes 2 can be effectively detached, thereby making room for the injection holes 2 to quickly release the chemical reaction pressure in the battery box.

[0059] A second communication hole 602 is formed in the plastic protective layer 6 below the explosion-proof valve mounting hole 3 , and the interior of the battery box covered by the cover body 1 is connected via the second communication hole 602 .

[0060] Two groups of electrode post through-holes 4 are provided, and are respectively provided with a positive electrode post assembly 41 and a negative electrode post assembly 42, and are connected to the electrode pieces inside the battery box; the positive electrode post assembly 41 includes a positive terminal 411 and a positive welding piece 412, which is fixed to the electrode post through-hole 4 through the positive welding piece 412, and the positive terminal 411 is fixed on the positive welding piece 412, so that the positive terminal 411 is connected to the electrode piece inside the battery box at the same time.

[0061] At the same time, the negative electrode column assembly 42 is composed of the same structural parts as the positive electrode column assembly 41, that is, the negative electrode column assembly 42 includes a negative terminal 421 and a negative electrode welding plate 422, which is fixed to another set of electrode column through holes 4 through the negative electrode welding plate 422, and the negative terminal 421 is fixed on the negative electrode welding plate 422, and the negative terminal 421 is simultaneously connected to the electrode inside the battery box.

[0062] The positive terminal 411 and the positive electrode welding tab 412 , as well as the negative terminal 421 and the negative electrode welding tab 422 are connected via sealing rings 402 .

[0063] At this time, the plastic protective layer 6 is located below the electrode post through-hole 4 and is set to be through-hole. Through the setting of the through-hole position, the positive electrode post assembly 41 and the negative electrode post assembly 42 can lead out the potential generated by the battery pole in the battery box.

[0064] In order to improve the fixation firmness of the positive pole assembly 41 and the negative pole assembly 42 on the two groups of electrode pole through-holes 4, a plurality of positioning grooves 401 are provided on the outer edge of the cover plate main body 1 where the electrode pole through-holes 4 are located. The positioning grooves 401 are radially opened outward from the center of the electrode pole through-holes 4, and the positive electrode welding piece 412 is fixedly welded on the positioning grooves 401. This welding method can greatly improve the firmness of the positive electrode welding piece 412 and the negative electrode welding piece 422.

[0065] The cover plate main body 1 and the battery liquid inside the battery box are isolated from each other by the plastic protective layer 6, which can reduce the corrosion of the battery liquid on the cover plate main body 1.

[0066] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the invention as claimed.

Claims

1. An explosion-proof battery cover assembly, comprising a cover body (1), a liquid injection hole (2), an explosion-proof valve mounting hole (3), and an electrode post through hole (4) provided on the cover body (1), characterized in that: A protective component (5) is provided on the injection hole (2), so that the protective component (5) forms a wrap around the outer wall where the injection hole (2) is located and forms a through hole running through the middle portion thereof, which is used for injecting battery liquid. The protective component (5) has a closed bottom and a flow channel (501) opened at the periphery, so that when the battery liquid is injected, the battery liquid flows into the cavity of the battery box from the side flow channel (501); An explosion-proof disc (31) is provided on the explosion-proof valve mounting hole (3); The electrode column through-holes (4) are provided in two groups, and are respectively provided with a positive electrode column assembly (41) and a negative electrode column assembly (42), and are communicated with the electrode sheets inside the battery box; The lower surface of the cover plate body (1) is covered with a plastic protective layer (6), so that the cover plate body (1) and the interior of the battery box are isolated from each other by the plastic protective layer (6).

2. The explosion-proof battery cover assembly according to claim 1, characterized in that: The injection holes (2) are provided in one or two groups on the upper surface of the cover plate body (1), and are located at the edge boss position of the through hole where the injection holes (2) are located, and are configured as an inclined slope structure that is narrow at the top and wide at the bottom; The lower surface where the boss structure is located protrudes from the lower surface where the cover plate body (1) is located.

3. The explosion-proof battery cover assembly according to claim 1, characterized in that: The protection component (5) is made of EPDM or TPV material.

4. The explosion-proof battery cover assembly according to claim 3, characterized in that: The boss extending toward the center of the injection hole (2) enables the protection component (5) to fully wrap the boss inside the injection hole (2) during injection molding, and forms a through hole for injection in the middle.

5. The explosion-proof battery cover assembly according to claim 4, characterized in that: The protective component (5) and the plastic protective layer (6) are made of the same material and are an integral injection-molded structure.

6. The explosion-proof battery cover assembly according to claim 4, characterized in that: The protective component (5) and the plastic protective layer (6) are independently processed and formed, and a first connecting hole (601) is provided below the plastic protective layer (6) where the protective component (5) is located, so that liquid can flow through the first connecting hole (601) when the liquid injection operation is performed through the liquid injection hole (2) where the protective component (5) is located.

7. The explosion-proof battery cover assembly according to claim 6, characterized in that: When the battery box explodes, the protective component (5) is separated from the arrangement on the injection hole (2) so as to quickly release the chemical reaction pressure in the battery box.

8. The explosion-proof battery cover assembly according to claim 1, characterized in that: A second communication hole (602) is provided in the plastic protective layer (6) area below the explosion-proof valve mounting hole (3), and the interior of the battery box covered by the cover plate body (1) is connected via the second communication hole (602).

9. The explosion-proof battery cover assembly according to claim 1, characterized in that: The positive pole column assembly (41) includes a positive terminal (411) and a positive welding sheet (412), which is fixed to the electrode pole through-hole (4) via the positive welding sheet (412). The positive terminal (411) is fixed to the positive welding sheet (412), and the positive terminal (411) is simultaneously connected to the pole piece inside the battery box. At the same time, the negative pole assembly (42) is composed of the same structural components as the positive pole assembly (41).

10. The explosion-proof battery cover assembly according to claim 9, characterized in that: A plurality of positioning grooves (401) are provided on the outer edge of the cover plate body (1) where the electrode pole through-hole (4) is located. The positioning grooves (401) are radially opened outward from the center of the electrode pole through-hole (4) and enable the welding piece (412) to be fixedly welded to the positioning grooves (401).

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