A negative electrode assembly

Abstract

The utility model provides a kind of negative pole assembly, negative pole assembly includes negative pole cover and negative pole connecting piece, negative pole cover is used to set in the end of battery shell, and negative pole cover is provided with liquid injection hole, and the liquid injection hole is formed with fillet in circumference, and the fillet extends with guide boss along battery liquid injection direction;Negative pole connecting piece is embedded between battery shell and negative pole cover, and the connecting position of negative pole connecting piece and battery shell and negative pole cover is provided with laser primary welding area.The utility model optimizes the welding mode and liquid injection hole sealing structure of negative pole connecting piece, solves the problem of low processing efficiency and high sealing risk in prior art, significantly improves processing efficiency, sealing reliability and battery safety.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery manufacturing technology, and in particular to a negative electrode component. Background Technology

[0002] Cylindrical batteries are widely used in new energy vehicles, energy storage systems, and other fields due to their high energy density and structural stability. The negative electrode structure of a cylindrical battery typically consists of a battery casing, a negative electrode connecting piece, and a negative electrode cover plate. In current manufacturing technology, the negative electrode connecting piece must first be welded to the cover plate and then to the casing. This process involves two welding steps, resulting in low processing efficiency and high cost.

[0003] Furthermore, the electrolyte injection hole on the negative electrode cover of cylindrical batteries is sealed with adhesive pins for better sealing. However, during production, due to process issues, the adhesive pins are prone to being squeezed and cut against the edge of the injection hole, generating debris. This debris may enter the battery, causing short circuits or electrolyte contamination, affecting battery performance and safety, and reducing battery yield.

[0004] Therefore, there is an urgent need for a technical solution that simplifies the processing procedure and improves sealing reliability. Utility Model Content

[0005] This invention provides a negative electrode assembly to address the shortcomings of low processing efficiency and high sealing risk in existing cylindrical batteries, thereby simplifying the processing procedure and improving sealing reliability.

[0006] This utility model provides a negative electrode assembly, including: a negative electrode cover plate and a negative electrode connecting piece. The negative electrode cover plate is used to be disposed at the end of the battery casing, and the negative electrode cover plate is provided with a liquid injection hole. The liquid injection hole is circumferentially rounded, and the rounded corner extends along the liquid injection direction of the battery with a guide boss. The negative electrode connecting piece is embedded between the battery casing and the negative electrode cover plate, and a laser primary welding area is provided at the connection position between the negative electrode connecting piece and the battery casing and the negative electrode cover plate.

[0007] According to the present invention, a negative electrode assembly is provided, the connection position includes the four ends of a negative electrode connecting piece, a battery casing and a negative electrode cover plate, an overlap is formed between the end of the battery casing and the negative electrode cover plate, and a laser primary welding area is formed between the overlap and the negative electrode connecting piece.

[0008] According to the present invention, the height of the guide boss in a negative electrode assembly is greater than or equal to 0.5 mm.

[0009] According to the present invention, the gap between the lower edge of the guide boss and the lower edge of the negative electrode connecting piece is greater than or equal to 0.25 mm and less than or equal to 0.60 mm.

[0010] According to the present invention, a negative electrode assembly further includes a sealing nail, which is used to be inserted into the injection hole to seal the injection hole.

[0011] According to the present invention, a negative electrode component is provided in which a sealing nail is interference-fitted with an injection hole.

[0012] According to the present invention, the interference fit between the sealing nail and the injection hole is greater than or equal to 0.05 mm.

[0013] According to the present invention, a negative electrode assembly further includes an injection port cover, which is sealed above the injection port.

[0014] According to the present invention, a negative electrode component is provided in which the liquid injection hole cap is sealed above the liquid injection hole by laser welding.

[0015] On the one hand, the negative electrode assembly provided by this utility model reduces welding steps, lowers production costs, and improves processing efficiency by using a laser one-time welding process at the connection positions of the negative electrode connecting piece, battery casing, and negative electrode cover plate around the perimeter.

[0016] On the other hand, the negative electrode assembly provided by this utility model reduces the risk of glue nail debris through the design of guide bosses and extended channels, solves the technical problems of low secondary welding efficiency and high risk of glue nail debris in traditional processes, and significantly improves battery safety and yield. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in 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 some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a cross-sectional view of the negative electrode assembly provided by this utility model.

[0019] Figure 2 This is a schematic diagram showing the dimensions of the guide boss of the negative electrode assembly provided by this utility model.

[0020] Figure 3 This is a schematic diagram of the laser primary welding zone of the negative electrode component provided by this utility model.

[0021] Figure 4 This is a schematic diagram of the structure of the negative electrode cover plate of the negative electrode assembly provided by this utility model.

[0022] Explanation of reference numerals in the attached figures:

[0023] 100. Battery casing;

[0024] 200. Negative electrode cover plate;

[0025] 300. Guide boss;

[0026] 400. Negative electrode connector;

[0027] 500, laser one-time welding zone;

[0028] 600. Sealing nails;

[0029] 700. Filling hole cap;

[0030] H1, the height of the guide boss;

[0031] H2, the gap between the lower edge of the guide boss and the lower edge of the negative electrode connecting piece;

[0032] W, Interference allowance. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0034] The following is combined with Figures 1-4 This invention describes a negative electrode component provided by the present invention.

[0035] Figure 1 This is a cross-sectional view of the negative electrode assembly provided by this utility model.

[0036] Figure 2 This is a schematic diagram showing the dimensions of the guide boss of the negative electrode assembly provided by this utility model.

[0037] Figure 3 This is a schematic diagram of the laser primary welding zone of the negative electrode component provided by this utility model.

[0038] Figure 4 This is a schematic diagram of the structure of the negative electrode cover plate of the negative electrode assembly provided by this utility model.

[0039] Reference Figures 1-4According to the present invention, a negative electrode assembly includes a negative electrode cover plate 200 and a negative electrode connecting piece 400. The negative electrode cover plate 200 is disposed at the end of the battery casing 100, and the negative electrode cover plate 200 is provided with a liquid injection hole. The liquid injection hole is circumferentially rounded, and a guide boss 300 extends from the rounded corner along the liquid injection direction of the battery. The negative electrode connecting piece 400 is embedded between the battery casing 100 and the negative electrode cover plate 200, and a laser primary welding area is provided at the connection position between the negative electrode connecting piece 400 and the battery casing 100 and the negative electrode cover plate 200.

[0040] In one embodiment of this utility model, the negative electrode structure includes a negative electrode cover plate 200 and a negative electrode connecting piece 400. The negative electrode cover plate 200 is used to be installed at the end of the battery casing 100. An injection hole is provided on the negative electrode cover plate 200. The injection hole is used to inject electrolyte into the battery, and the circumferential direction of the injection hole is rounded.

[0041] A guide boss 300 extends from the rounded corner along the direction of electrolyte injection. During electrolyte injection, the guide boss 300 guides the electrolyte to flow more smoothly and accurately into the battery, reducing splashing and deviation of the electrolyte during the injection process, and improving injection efficiency and uniformity.

[0042] The negative electrode connector 400 is embedded between the battery casing 100 and the negative electrode cover 200. This embedded installation method ensures that the negative electrode connector 400 can effectively connect the battery casing 100 and the negative electrode cover 200.

[0043] A laser primary welding zone is provided at the connection point between the negative electrode connecting piece 400 and the battery casing 100 and the negative electrode cover plate 200. Through laser welding technology, a strong and reliable connection is achieved in this area. Laser welding allows for precise control of welding heat and welding position, ensuring the sealing and conductivity of the connection, and preventing problems such as loosening and leakage at the connection point.

[0044] Therefore, according to one embodiment of the present invention, the negative electrode assembly improves the electrolyte injection process into the battery by using rounded corners around the injection hole and guide bosses 300 extending along the injection direction. The rounded corners reduce resistance during electrolyte injection, and the guide bosses 300 guide the electrolyte to flow in quickly and accurately, making the injection process smoother, effectively shortening the injection time, and ensuring the uniformity of electrolyte distribution inside the battery, thus improving the overall performance consistency of the battery. The laser-welded area at the connection point between the negative electrode connecting piece 400 and the battery casing 100 and negative electrode cover plate 200 utilizes the high precision and high energy density characteristics of laser welding to form a robust welded joint. This not only ensures the stability of the electrical connection and reduces resistance, facilitating current transmission during battery charging and discharging, but also enhances the mechanical strength of the connection, preventing loosening due to vibration, temperature changes, and other factors, thereby improving the reliability and service life of the battery.

[0045] Furthermore, laser welding allows for precise control of the welding process, ensuring a tight bond between the welded parts and effectively preventing electrolyte leakage from the battery, thus guaranteeing the battery's airtightness. Good airtightness is crucial for maintaining a stable internal chemical environment, preventing performance degradation or even failure due to electrolyte leakage, and improving the battery's safety and stability under various operating conditions.

[0046] The negative electrode assembly provided by this utility model also includes a sealing nail 600, which is inserted into the liquid injection hole.

[0047] The guide boss 300 guides the sealing nail 600 into the injection hole to seal it, reducing the possibility of the nail breaking. Simultaneously, the extended guide channel prevents foreign objects from the sealing nail 600, caused by squeezing and cutting against the edge of the injection hole, from entering the cylindrical battery.

[0048] As can be seen from the structure of the above negative electrode assembly, this utility model uses laser welding to weld the battery shell 100, the negative electrode cover plate 200 and the negative electrode connecting piece 400 together. This assembly method can be completed in one welding, reducing the manufacturing process of the negative electrode assembly, improving assembly efficiency and battery reliability.

[0049] According to the present invention, a negative electrode assembly is provided, wherein the connection position of the negative electrode assembly includes the four ends of the negative electrode connecting piece 400, the battery casing 100 and the negative electrode cover plate 200, an overlap portion is formed between the end of the battery casing 100 and the negative electrode cover plate 200, and a laser primary welding area is formed between the overlap portion and the negative electrode connecting piece 400.

[0050] In one embodiment of this invention, the connection points are located at the periphery of the negative electrode connecting piece 400, the battery casing 100, and the negative electrode cover plate 200, with welding or fixing operations covering the entire annular contact surface. This design ensures a uniform distribution of stress generated by external pressure, internal thermal expansion, and mechanical vibration, avoiding localized stress concentration and significantly reducing the risk of weld cracking. Furthermore, the laser welding at the periphery forms a seamless seal, eliminating micro-gaps that may remain with traditional spot welding or localized welding, thereby improving sealing performance.

[0051] According to the present invention, the height H1 of the guide boss 300 of the negative electrode assembly is ≥0.5 mm.

[0052] In one embodiment of this utility model, the height H1 of the guide boss 300 has a specific design requirement, namely, H1 ≥ 0.5 mm. The rounded corner of the guide boss 300 extends outward from the circumferential direction of the injection hole along the direction of battery injection. This height limitation ensures that the guide boss 300 can fully perform its guiding function in the entire injection system.

[0053] From a structural design perspective, when the height H1 reaches 0.5 mm or more, the guide boss 300 can provide a sufficient guiding path for the electrolyte during the electrolyte injection process.

[0054] In actual production, the guide boss 300 of this height can be achieved through processes such as precision mold manufacturing or high-precision machining to ensure that its dimensional accuracy meets the design requirements, thereby accurately installing it around the liquid injection hole of the negative electrode cover plate 200.

[0055] A guide boss 300 with a height H1 ≥ 0.5 mm provides a more stable and effective guiding effect for the electrolyte. During electrolyte injection, the sufficiently high guide boss 300 allows the electrolyte to flow into the battery along a predetermined path, reducing uneven electrolyte distribution caused by diffusion and splashing during injection. This helps improve the consistency of electrolyte distribution throughout the battery, thereby ensuring the stability of battery performance during charging and discharging.

[0056] Furthermore, the appropriate height allows the guide boss 300 to better guide the electrolyte quickly through the injection hole into the battery. Compared to guide bosses with insufficient height, the guide boss 300 with a height H1 ≥ 0.5 mm can effectively shorten the injection time, improve the injection efficiency in the battery production process, and reduce production costs.

[0057] According to the present invention, the gap H2 between the lower edge of the guide boss 300 and the lower edge of the negative electrode connecting piece 400 is in the range of 0.25 mm ≤ H2 ≤ 0.60 mm.

[0058] In one embodiment of this utility model, the gap between the guide boss 300 and the negative electrode connecting piece 400 is designed to prevent the guide boss 300 from squeezing the battery electrode assembly, while reducing the force of the electrolyte scouring the battery electrode assembly and avoiding damage to the battery electrode assembly.

[0059] According to the present invention, a negative electrode component is provided in which the sealing nail 600 is interference-fitted with the liquid injection hole, and the interference amount W is ≥ 0.05 mm.

[0060] In one embodiment of this utility model, the sealing nail 600 is designed to achieve an interference fit with the injection hole on the negative electrode cover plate 200. That is, the size of the sealing nail 600 is slightly larger than the size of the injection hole, and when the sealing nail 600 is installed into the injection hole, a certain amount of compression will occur between the two. Furthermore, it is explicitly specified that the interference amount W of this interference fit must satisfy W≥0.05 mm.

[0061] Sealing nails 600 are typically made of materials with good sealing performance and a certain degree of elasticity, such as rubber or special polymer materials. During installation, the sealing nail 600 is pressed into the injection hole under appropriate pressure, utilizing the elastic deformation and interference fit of the material to achieve a tight seal. The interference fit between the sealing nail 600 and the injection hole, along with a small amount of lateral compressive force, enhances the pressure resistance of the sealing nail 600, thereby improving sealing performance.

[0062] The design, with an interference fit W ≥ 0.05 mm, ensures a very tight fit between the sealing pin 600 and the electrolyte injection hole. This tight fit effectively prevents electrolyte leakage from inside the battery and also prevents external impurities such as air and moisture from entering the battery. Good sealing is crucial for maintaining a stable internal chemical environment, preventing performance degradation and short circuits caused by electrolyte leakage or impurities, thus significantly improving battery safety and reliability.

[0063] According to the present invention, a negative electrode assembly further includes an injection hole cover 700, which is sealed above the injection hole.

[0064] According to the present invention, a negative electrode assembly is provided in which a sealing nail 600 and an injection hole cover 700 are laser welded together.

[0065] Through the aforementioned laser welding process, a continuous and defect-free weld is formed between the injection port cover 700 and the sealing nail 600, eliminating the micro-gaps that may occur with traditional gluing or mechanical pressing, thus improving sealing performance and reducing the risk of electrolyte leakage. Furthermore, the localized high temperature of laser welding only affects the welding area, avoiding thermal damage to surrounding materials (such as the negative electrode cover plate and the material of the sealing nail). After welding, the injection port cover 700 and the sealing nail 600 form an integrated structure, maintaining structural integrity.

[0066] In addition, the laser welding process is automated, with short welding time per piece and no need for additional sealant curing time, which improves production line efficiency. Furthermore, the welding parameters are precise and controllable, resulting in stable yield and reduced rework costs.

[0067] In summary, the negative electrode assembly provided by this utility model adopts a laser one-time welding process at the connection positions of the negative electrode connecting piece, the battery casing and the negative electrode cover plate, so that an overlap is formed between the end of the battery casing and the negative electrode cover plate, and the laser one-time welding area is formed between the overlap and the negative electrode connecting piece, which reduces welding steps, lowers production costs and improves processing efficiency.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A negative electrode component, characterized in that, include: A negative electrode cover plate is provided at the end of the battery casing. The negative electrode cover plate is provided with a liquid injection hole. The liquid injection hole is circumferentially rounded. The rounded corner extends along the liquid injection direction of the battery and has a guide protrusion. A negative electrode connecting piece is used to be embedded between the battery casing and the negative electrode cover plate. The connection position between the negative electrode connecting piece and the battery casing and the negative electrode cover plate is provided with a laser primary welding area.

2. The negative electrode assembly according to claim 1, characterized in that, The connection points include the four ends of the negative electrode connecting piece, the battery casing, and the negative electrode cover plate. An overlap is formed between the end of the battery casing and the negative electrode cover plate. The laser primary welding area is formed between the overlap and the negative electrode connecting piece.

3. The negative electrode assembly according to claim 1, characterized in that, The height of the guide boss is greater than or equal to 0.5 mm.

4. The negative electrode assembly according to any one of claims 1-3, characterized in that, The gap between the lower edge of the guide boss and the lower edge of the negative electrode connecting piece is greater than or equal to 0.25 mm and less than or equal to 0.60 mm.

5. The negative electrode assembly according to claim 1, characterized in that, It also includes a sealing pin, which is used to be inserted into the injection hole to seal the injection hole.

6. The negative electrode assembly according to claim 5, characterized in that, The sealing nail is interference-fitted with the injection hole.

7. The negative electrode assembly according to claim 6, characterized in that, The interference fit between the sealing nail and the injection hole is greater than or equal to 0.05 mm.

8. The negative electrode assembly according to claim 6, characterized in that, It also includes a liquid injection port cover, which is sealed above the liquid injection port.

9. The negative electrode assembly according to claim 8, characterized in that, The injection port cap is sealed above the injection port by laser welding.

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