An electrode assembly for a lithium secondary battery

Abstract

The utility model relates to the technical field of electric core liquid injection sealing, disclose a kind of electric core liquid injection hole sealing structure, including substrate and sealing nail, wherein, the substrate is equipped with liquid injection hole, and the liquid injection hole includes the liquid injection step and liquid injection through-hole of intercommunication arrangement;The sealing nail includes glue nail and aluminium nail, the glue nail and aluminium nail integrally formed setting, the aluminium nail is set in the liquid injection step, the glue nail is worn in the liquid injection through-hole;The upper surface of the aluminium nail is provided with pickup groove.Aluminium nail and glue nail integrally formed do not exist the phenomenon that aluminium nail is warped, and the upper surface of aluminium nail has pickup groove, and the clamp pickup of equipment is facilitated.

Description

Technical Field

[0001] This utility model relates to the field of battery cell liquid injection sealing technology, and in particular to a battery cell liquid injection hole sealing structure. Background Technology

[0002] After the battery cell is filled with electrolyte, the filling hole needs to be sealed to prevent external moisture from entering the cell. For example, Chinese utility model patent CN222507944U discloses a fluororubber sealing nail structure for power batteries. In the above technical solution, the filling hole is sealed by first inserting a rubber nail for temporary sealing, and then adding an aluminum nail for laser welding. The rubber nail and aluminum nail are sealed together. However, due to the small size of the rubber nail, the equipment has limited precision, making it difficult for the equipment to pick up the nail. Moreover, the height of the nail cannot be accurately determined, and the nail is prone to warping. This can indirectly mask the defects in the laser welding of the aluminum nail, leading to missed detection by helium detection. Utility Model Content

[0003] To overcome at least one of the defects described in the prior art, this utility model provides a battery cell injection hole sealing structure. By integrally molding the aluminum nail and the adhesive nail, the phenomenon of the aluminum nail prying off is eliminated, and the upper surface of the aluminum nail has a pickup groove for easy pickup by the equipment's clamps.

[0004] The technical solution of this utility model is implemented as follows: A battery cell electrolyte filling hole sealing structure includes a substrate and a sealing pin. The substrate has an electrolyte filling hole, which includes an electrolyte filling step and an electrolyte filling through hole that are connected to each other. The sealing pin includes a plastic pin and an aluminum pin, which are integrally formed. The aluminum pin is disposed in the electrolyte filling step, and the plastic pin passes through the electrolyte filling through hole. The upper surface of the aluminum pin has a pickup groove.

[0005] Based on the above technical solutions, preferably, a busbar is provided on the lower surface of the substrate, and the busbar is fixedly connected to the substrate.

[0006] Based on the above technical solutions, preferably, the manifold is provided with a clearance groove for avoiding the rubber nail.

[0007] Based on the above technical solutions, preferably, the outer peripheral surface of the aluminum nail is welded and fixed to the inner peripheral surface of the liquid injection step.

[0008] Based on the above technical solutions, preferably, the upper surface of the aluminum nail is flush with the upper surface of the liquid injection step.

[0009] Based on the above technical solutions, preferably, the picking groove is an annular groove, and the annular groove surrounds and forms a picking plane.

[0010] Based on the above technical solutions, preferably, the diameter of the picking plane is greater than 2mm.

[0011] Based on the above technical solutions, preferably, the adhesive nail is made of fluororubber.

[0012] Based on the above technical solutions, preferably, the aluminum nail has an embedding groove inside, the top of the adhesive nail has an embedding block, and the embedding block is fixedly connected to the embedding groove.

[0013] Based on the above technical solutions, preferably, the horizontal distance between the embedding groove and the outer peripheral surface of the aluminum nail is greater than 2mm.

[0014] In summary, the battery cell injection hole sealing structure provided by this utility model has the following advantages over the prior art: (1) A pickup groove is set on the upper surface of the aluminum nail, and the diameter of the pickup plane formed by the center of the pickup groove is greater than 2mm. This design is convenient to adapt to the pickup needs of the equipment and solves the problem of pickup difficulty caused by the small size of traditional plastic nails. (2) The aluminum nail and the glue nail are integrally formed and are not easy to fall off. There is no phenomenon of aluminum nails being lifted. Moreover, the upper surface of the aluminum nail is flush with the upper surface of the liquid injection step, which avoids the phenomenon of inaccurate nailing height and nail lifting, and improves the flatness of the structure. (3) By setting the horizontal distance between the embedded groove and the outer circumference of the aluminum nail to be greater than 2mm, the high temperature during welding can be avoided from damaging the glue nail. (4) The material of the nail is fluororubber, which significantly improves the sealing effect and sealing durability. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a first-view perspective three-dimensional structural diagram of an embodiment of the present utility model; Figure 2 This is a second-view perspective three-dimensional structural diagram of an embodiment of the present utility model; Figure 3 This is a cross-sectional structural diagram of an embodiment of the present utility model; Figure 4 This is a first-view perspective three-dimensional structural diagram of the aluminum nail according to an embodiment of the present utility model; Figure 5This is a two-dimensional structural diagram of the aluminum nail from the second perspective of an embodiment of the present utility model; Figure 6 This is a three-dimensional structural diagram of the adhesive nail according to an embodiment of the present utility model; Figure 7 This is a schematic diagram of the planar structure of the adhesive nail according to an embodiment of the present utility model; Figure 8 This is a three-dimensional structural diagram of the busbar according to an embodiment of the present utility model; Figure 9 This is a schematic diagram of the cross-sectional structure of the aluminum nail according to an embodiment of the present utility model; Figure 10 This is a schematic diagram of the cross-sectional structure of the substrate according to an embodiment of the present invention.

[0017] The meanings of the reference numerals in the attached drawings are as follows: 1. Substrate; 11. Injection hole; 111. Injection step; 112. Injection through hole; 2. Sealing nail; 21. Adhesive nail; 211. Embedded block; 22. Aluminum nail; 221. Pick-up groove; 2211. Pick-up plane; 222. Embedded groove; 3. Manifold; 31. Clearance groove. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0020] See Figures 1-10 This utility model discloses a sealing structure for the electrolyte injection hole 11 of a battery cell, including a substrate 1, a sealing nail 2, and a manifold 3.

[0021] See Figure 1 , Figure 2 and Figure 10As shown, in this embodiment, substrate 1 is part of the top cover of the battery cell. Only substrate 1 will be described here. Substrate 1 has a liquid injection hole 11. Specifically, the liquid injection hole 11 is located at the center of substrate 1 and is opened along the thickness direction of substrate 1. The liquid injection hole 11 includes a liquid injection step 111 and a liquid injection through hole 112. The liquid injection step 111 and the liquid injection through hole 112 are connected. The liquid injection hole 11 is not a straight hole, but is designed as a stepped hole. Specifically, the cross-section of the liquid injection step 111 is trapezoidal, and the cross-section of the liquid injection through hole 112 is rectangular. The diameter of the liquid injection through hole 112 is smaller than the diameter of the liquid injection step 111. This design facilitates the formation of a stepped surface by the liquid injection step 111. The stepped surface provides a precise reference guide for the subsequent positioning and welding of the aluminum nail 22. Moreover, the liquid injection through hole 112 can easily accommodate the subsequent aluminum nail 22.

[0022] See Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown, in this embodiment, the sealing nail 2 includes a plastic nail 21 and an aluminum nail 22, which are integrally formed. The aluminum nail 22 serves as the upper part of the sealing nail 2, and the plastic nail 21 serves as the lower part. Specifically, the plastic nail 21 and the aluminum nail 22 are integrally injection molded structures, and there is no phenomenon of the aluminum nail 22 being warped. The aluminum nail 22 is disposed within the liquid injection step 111, and the plastic nail 21 passes through the liquid injection through hole 112. Since the cross-section of the liquid injection step 111 is trapezoidal, the cross-section of the aluminum nail 22 is also trapezoidal. This design facilitates the perfect fit of the aluminum nail 22 to the liquid injection step 111. Since the plastic nail 21 and the aluminum nail 22 are integrally formed, the lower part of the plastic nail 21 passes through the liquid injection through hole 112, while the lower part of the plastic nail 21 is exposed. Moreover, the aluminum nail 22 and the plastic nail 21 form a double-layer sealing effect, protecting the safety of the battery cell.

[0023] More specifically, see Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 9 and Figure 10 As shown, the aluminum nail 22 has an internal embedding groove 222, and the plastic nail 21 has an embedding block 211 on its top. The embedding block 211 is fixedly connected to the embedding groove 222. Specifically, the embedding groove 222 is T-shaped, and the embedding block 211 is also T-shaped, with the entire embedding block 211 located within the embedding groove 222. During manufacturing, the molten plastic nail 21 is injected into the mold of the aluminum nail 22 with the embedding groove 222. After cooling, the embedding block 211 of the plastic nail 21 and the embedding groove 222 of the aluminum nail 22 are firmly bonded together by injection molding, ensuring the stability of both the aluminum nail 22 and the plastic nail 21 during subsequent assembly and use.

[0024] See Figure 2 and Figure 8 As shown, in this embodiment, a busbar 3 is provided on the lower surface of the substrate 1. The busbar 3 is fixedly connected to the substrate 1. The busbar 3 is a thin sheet made of copper or aluminum. The busbar 3 is located on the lower surface of the substrate 1 and is used to collect the current of the electrode plates inside the battery cell. It should also be noted that, in order to avoid interference between the busbar 3 and the adhesive nail 21 passing through the substrate 1, a clearance groove 31 is provided on the busbar 3 to avoid the adhesive nail 21. Specifically, the clearance groove 31 is also opened at the center of the busbar 3. The fixed connection between the busbar 3 and the substrate 1 is welding, which makes the overall structure more robust. The size of the clearance groove 31 is adapted to the adhesive nail 21 to ensure that the bottom of the adhesive nail 21 can pass freely.

[0025] See Figure 3 As shown, in this embodiment, the outer peripheral surface of the aluminum nail 22 is welded and fixed to the inner peripheral surface of the liquid injection step 111. Welding and fixing can achieve a firm connection between the aluminum nail 22 and the substrate 1, forming a closed annular sealing surface, which effectively prevents external moisture, air, dust and other impurities from entering the cell. The welding method has better airtightness and watertightness, and can withstand temperature changes during the long-term use of the cell, avoiding sealing failure. Specifically, the welding method between the aluminum nail 22 and the liquid injection step 111 is laser welding. After the laser beam is focused, the spot is extremely small, which can accurately act on the annular mating surface of the aluminum nail 22 and the liquid injection step 111, avoiding thermal damage to the surrounding glue nail 21, substrate 1 or busbar 3; at the same time, it can achieve narrow weld seam welding, without occupying extra space, perfectly matching the compact and precise design characteristics of the liquid injection hole 11 sealing structure.

[0026] In this embodiment, the adhesive nail 21 is made of fluororubber. Fluororubber has high sealing reliability. The electrolyte inside the battery cell is highly corrosive. Existing solutions usually use molten rubber, which is easily corroded, leading to sealing failure. Fluororubber contains fluorine atoms, has strong chemical stability, and can withstand the erosion of electrolyte and corrosive media such as acids and alkalis for a long time. This ensures that the adhesive nail 21 maintains its sealing integrity throughout the entire life cycle of the battery cell, preventing electrolyte leakage or intrusion of external impurities. Moreover, the integral molding of fluororubber and adhesive nail 21 has good compatibility. During the molding process, it can fit tightly with the embedding groove 222 of aluminum nail 22 without peeling or falling off, ensuring the stability of the integrated structure of the sealing nail 2.

[0027] In this embodiment, the distance between the embedded groove 222 and the outer peripheral surface of the aluminum nail 22 is greater than 2mm. Since local high temperatures are generated during laser welding, and the material of the adhesive nail 21 is fluororubber, its long-term temperature resistance does not exceed 200℃. If the adhesive nail 21 is too close to the welding point, it is easy for the adhesive nail 21 to age, melt or crack under high temperature environment. Maintaining a distance of more than 2mm can effectively form thermal insulation through the body of the aluminum nail 22, blocking the high temperature from being conducted to the adhesive nail 21, avoiding the problem of sealing failure of the adhesive nail 21 due to high temperature, and ensuring that the sealing performance of fluororubber can be stable for a long time.

[0028] See Figure 3 and Figure 9 As shown, in this embodiment, the upper surface of the aluminum nail 22 is flush with the upper surface of the liquid injection step 111. This flush design keeps the surface of the substrate 1 flat, without any additional protrusions or depressions, avoiding interference with other components during the cell packaging and module assembly process. This design prevents packaging difficulties and structural jamming caused by protruding aluminum nails 22, and also avoids the formation of dust and liquid accumulation dead zones due to depressions, ensuring the compactness of the overall cell structure and smooth assembly, thus meeting the needs of large-scale module integration.

[0029] See Figure 1 and Figure 5 As shown, in this embodiment, the picking groove 221 is an annular groove, which surrounds and forms a picking plane 2211. The diameter of the picking plane 2211 is greater than 2mm. The annular groove surrounding the picking plane 2211 provides a flat working surface for the automated equipment, making it convenient for the equipment's clamps to pick up the items. The design of the annular structure and the diameter of the picking plane 2211 ensures that the working surface is large enough. Even if there is a slight deviation in the equipment positioning, the sealing nail 2 can still be picked up. This solves the problem of the traditional glue nail 21 being small in size and difficult to pick up, and reduces the assembly error rate.

[0030] In this embodiment, the length of the glue nail 21 is greater than the sum of the lengths of the injection through hole 112 and the clearance hole. This design prevents sealing failure caused by the glue nail 21 being tilted, thus ensuring the sealing effect.

[0031] The technical means disclosed in this utility model are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications are also considered within the scope of protection of this utility model.

Claims

1. A sealing structure for the electrolyte injection port of a battery cell, characterized in that, Includes a substrate (1) and a sealing pin (2), wherein, The substrate (1) is provided with a liquid injection hole (11), which includes a liquid injection step (111) and a liquid injection through hole (112) connected in series. The sealing nail (2) includes a rubber nail (21) and an aluminum nail (22), which are integrally formed. The aluminum nail (22) is disposed in the injection step (111), and the rubber nail (21) passes through the injection through hole (112). The upper surface of the aluminum nail (22) is provided with a pickup groove (221).

2. The cell injection hole sealing structure according to claim 1, characterized in that, A busbar (3) is provided on the lower surface of the substrate (1), and the busbar (3) is fixedly connected to the substrate (1).

3. The cell injection hole sealing structure according to claim 2, characterized in that, The manifold (3) is provided with a clearance groove (31) for avoiding the rubber nail (21).

4. The cell injection hole sealing structure according to claim 1, characterized in that, The outer peripheral surface of the aluminum nail (22) is welded and fixed to the inner peripheral surface of the liquid injection step (111).

5. The cell injection hole sealing structure according to claim 1, characterized in that, The upper surface of the aluminum nail (22) is flush with the upper surface of the liquid injection step (111).

6. The cell injection hole sealing structure according to claim 1, characterized in that, The pickup groove (221) is an annular groove, and the annular groove surrounds and forms a pickup plane (2211).

7. The cell injection hole sealing structure according to claim 6, characterized in that, The diameter of the picking plane (2211) is greater than 2 mm.

8. The cell electrolyte injection port sealing structure according to claim 1, characterized in that, The adhesive nail (21) is made of fluororubber.

9. The cell electrolyte injection port sealing structure according to claim 1, characterized in that, The aluminum nail (22) has an embedded groove (222) inside, and the top of the glue nail (21) has an embedded block (211), which is fixedly connected to the embedded groove (222).

10. The cell injection hole sealing structure according to claim 9, characterized in that, The horizontal distance between the embedded groove (222) and the outer peripheral surface of the aluminum nail (22) is greater than 2 mm.

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