Battery roll core and cylindrical battery

Abstract

The utility model discloses a kind of battery roll core and cylindrical battery, including positive pole piece, negative pole piece and diaphragm, positive pole piece is coated with positive pole slurry with clearance, the positive pole slurry is formed with the positive pole blank area for connecting positive pole lug between, positive pole lug is spaced apart on positive pole piece by positive pole blank area, negative pole piece is coated with negative pole slurry with clearance, the blank area for connecting negative pole lug is formed between negative pole slurry, negative pole lug is spaced apart on negative pole piece by negative pole blank area. Gap coating process is used on positive and negative pole piece to form blank area for setting lug, and make positive and negative lug spaced apart on the blank area, improve the liquid injection process efficiency and electrolyte infiltration effect of cylindrical battery, solve the problem of slow liquid injection speed caused by lug full coverage, help shorten the process time of battery manufacturing, improve overall production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery core and a cylindrical battery. Background Technology

[0002] With the rapid development of new energy vehicles and energy storage technologies, large-size cylindrical lithium battery technology has emerged and gained widespread attention to meet the demands for high energy density, long driving range, and low cost. The core feature of this technology is increasing energy density and integration efficiency by increasing the volume of individual cells. Its manufacturing process typically involves winding positive and negative electrode sheets coated with active materials together with a separator to form a battery core. The tab structure extending from the electrode sheets is a key component connecting the internal and external circuitry of the cell, and its design and manufacturing method directly affect the battery's production efficiency and final performance.

[0003] In traditional technologies, several improved solutions have emerged to address the problem of electrolyte penetration into the interior of large-size cylindrical batteries. For example, the technology disclosed in patent CN220138635U addresses this issue through structural optimization of the electrode sheet. Specifically, a first through-hole is provided near the root of the active material coating on the electrode tab, and a second through-hole is provided in the area of ​​the electrode sheet coated with the active material. The purpose of this design is to create additional flow channels for the electrolyte through these holes, especially at the root of the electrode tab and in the middle of the core, thereby improving the lateral and radial wetting effect of the electrolyte.

[0004] However, current electrode structures and battery manufacturing methods still face fundamental challenges in improving production efficiency, with the most prominent and critical issue being electrolyte injection efficiency. After large-size cells are wound, their internal structure is highly compacted. Especially with full-tab or continuous electrode designs, the electrodes themselves severely obscure the core end face, forming a dense physical barrier. This results in significant flow resistance for the electrolyte during injection, making it difficult to quickly and evenly penetrate the central area of ​​the core. Although attempts have been made to increase local flow channels through methods such as opening holes, the overall high-density structure of the core has not been fundamentally changed. To ensure wetting effect, existing processes have had to adopt strategies such as extending the injection time and increasing the subsequent standing wetting time. However, this directly slows down the production cycle, forming a key bottleneck in the entire production process, significantly reducing production efficiency and increasing manufacturing costs. Utility Model Content

[0005] Therefore, it is necessary to provide a battery core and a cylindrical battery to address the above problems.

[0006] This application provides a battery core, including a positive electrode sheet, a negative electrode sheet, and a separator. The positive electrode sheet is coated with a positive electrode slurry at intervals, and positive electrode blank areas for connecting positive electrode tabs are formed between the positive electrode slurries. The positive electrode tabs are spaced apart on the positive electrode sheet through the positive electrode blank areas. The negative electrode sheet is coated with a negative electrode slurry at intervals, and negative electrode tabs are spaced apart on the negative electrode sheet through the negative electrode blank areas.

[0007] Optionally, the positive electrode tab and the positive electrode sheet are welded together.

[0008] Optionally, the negative electrode tab and the negative electrode sheet are welded together.

[0009] Optionally, a first through hole is provided on the end of the positive electrode tab away from the positive electrode sheet.

[0010] Optionally, a second through hole is provided on the end of the negative electrode tab away from the negative electrode sheet.

[0011] Optionally, the first through hole and / or the second through hole are circular holes.

[0012] Optionally, the positive electrode tab is provided with a first variable diameter structure at the end away from the positive electrode sheet, and the first variable diameter structure converges in the direction away from the positive electrode sheet.

[0013] Optionally, the negative electrode tab is provided with a second variable diameter structure at the end away from the negative electrode sheet, and the second variable diameter structure converges in the direction away from the negative electrode sheet.

[0014] Optionally, the first variable diameter structure and / or the second variable diameter structure are trapezoidal structures.

[0015] This application also provides a cylindrical battery, including the battery core described above.

[0016] Compared with the prior art, the technical solution provided in this application has the following advantages: The aforementioned battery core employs a gap coating process on both the positive and negative electrode sheets to form blank areas for setting the tabs, with the positive and negative tabs spaced apart within these blank areas. This improves the efficiency of the electrolyte injection process and the electrolyte wetting effect in cylindrical batteries. According to background technology, traditional full-tab or continuous tab designs result in very high density in the wound battery core, especially in large-size cylindrical batteries, making it difficult for the electrolyte to quickly and evenly penetrate into the core, which greatly limits battery production efficiency. In this embodiment, the tabs are spaced apart within the blank areas of the electrode sheets, replacing the continuously covered tab structure. When the positive and negative electrode sheets are wound together with the separator into a core, these areas not covered by the tab metal sheets form through gaps or channels on the end face of the core. These gaps provide a low-resistance path for electrolyte injection and flow, allowing it to penetrate deeper into the core more quickly, thereby effectively improving the injection speed and wetting efficiency. This design directly solves the problem of slow liquid injection speed caused by full tab coverage, which helps to shorten the battery manufacturing process time and improve overall production efficiency. Attached Figure Description

[0017] Figure 1 This is a perspective view of the present utility model; Figure 2 This is a diagram showing the unfolded negative electrode sheet with tabs according to this utility model. Figure 3 This is a diagram showing the unfolded positive electrode sheet with tabs according to this invention.

[0018] Explanation of reference numerals in the attached figures: 1. Negative electrode sheet; 2. Negative electrode slurry; 3. Negative electrode tab; 4. Positive electrode sheet; 5. Positive electrode slurry; 6. Positive electrode tab; 7. Separator. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0020] See Figures 1 to 3An embodiment of this utility model provides a battery core, including a positive electrode sheet 4, a negative electrode sheet 1, and a separator 7. The positive electrode sheet 4 is coated with a positive electrode slurry 5 at intervals, and positive electrode blank areas are formed between the positive electrode slurries 5 for connecting positive electrode tabs 6. The positive electrode tabs 6 are arranged on the positive electrode sheet 4 at intervals through the positive electrode blank areas. The negative electrode sheet 1 is coated with a negative electrode slurry 2 at intervals, and negative electrode blank areas are formed between the negative electrode slurries 2 for connecting negative electrode tabs 3. The negative electrode tabs 3 are arranged on the negative electrode sheet 1 at intervals through the negative electrode blank areas.

[0021] In this embodiment, a gap coating process is used on both the positive and negative electrode sheets to form blank areas for setting the tabs, and the positive and negative tabs are spaced apart in these blank areas, improving the electrolyte injection process efficiency and electrolyte wetting effect of the cylindrical battery. According to the background art, traditional full-tab or continuous tab designs result in very high density of the wound battery core, especially in large-size cylindrical batteries, making it difficult for the electrolyte to quickly and evenly penetrate into the core, which greatly limits battery production efficiency. In this embodiment, the tabs are spaced apart in the blank areas of the electrode sheets, replacing the continuously covered tab structure. When the positive and negative electrode sheets are wound together with the separator 7 into a core, these areas not covered by the tab metal sheets form through gaps or channels on the end face of the core. These gaps provide a low-resistance path for electrolyte injection and flow, allowing it to penetrate deeper into the core more quickly, thereby effectively improving the injection speed and wetting efficiency. This design directly solves the problem of slow injection speed caused by full tab coverage, helping to shorten the battery manufacturing process time and improve overall production efficiency. In this embodiment, the positive electrode 4 is specifically an aluminum foil, the positive electrode tab 6 is specifically an aluminum sheet, the negative electrode 1 is specifically a copper foil, and the negative electrode tab 3 is specifically a copper sheet.

[0022] In one embodiment, the positive electrode tab 6 and the positive electrode sheet 4 are welded together. Welding achieves functional separation between the tab and the current collector (positive electrode aluminum foil). To achieve high energy density, the current collector typically needs to be very thin, while the tab, as the main current path, needs sufficient thickness and cross-sectional area to carry large currents and ensure mechanical strength. Welding allows for the selection of specialized, thicker aluminum sheets as the tab material, with thickness adjustable according to process requirements, without being limited by thin aluminum foil current collectors. This optimizes battery conductivity and structural reliability without sacrificing energy density. Secondly, from a process perspective, welding is a key technology for achieving the spaced tab structure in the aforementioned embodiment. Welding allows for the flexible and precise fixing of individual tab sheets in the blank areas of the electrode sheet. This process not only forms the liquid injection channel and improves injection efficiency but also simplifies the tab manufacturing process. Compared to complex laser cutting or stamping from a single electrode sheet to form an integrated tab, directly welding pre-fabricated tab sheets may be more efficient and help reduce manufacturing costs.

[0023] In one embodiment, the negative electrode tab 3 is welded to the negative electrode sheet 1. Similarly, the welded connection between the negative electrode tab 3 and the negative electrode sheet 1 provides crucial support for material optimization, improved electrical performance, and process implementation on the negative electrode side. Through welding, the negative electrode current collector (copper foil) and the negative electrode tab 3 (typically a copper sheet or copper-nickel composite strip) can be designed and selected independently. Thin copper foil maximizes the proportion of active material, while thicker, specialized tab materials with superior mechanical and welding properties ensure low current transmission losses and long-term connection reliability. This material decoupling is essential for high-performance batteries.

[0024] See Figures 1 to 3 In one embodiment, the positive electrode tab 6 has a first through hole at the end furthest from the positive electrode plate 4. Specifically, after the core is placed into the battery casing, the tab needs to be precisely aligned and welded to the battery cover or current collector. The through hole can be used to cooperate with the positioning structure (such as a positioning pin) on the current collector to ensure that the tab can accurately stop at the preset welding position after bending. This mechanical positioning method is more reliable than simple visual positioning, and can significantly improve the accuracy and consistency of welding, thereby ensuring the reliable connection of the current conduction path and reducing the risk of battery failure due to poor welding. It is a key link in realizing a high-efficiency, high-yield automated production line and is of great significance for ensuring the quality consistency of cylindrical batteries in large-scale production.

[0025] See Figures 1 to 3 In one embodiment, a second through hole is provided on the end of the negative electrode tab 3 furthest from the negative electrode plate 1. Corresponding to the design of the positive electrode tab 6, this embodiment provides a second through hole on the end of the negative electrode tab 3 furthest from the negative electrode plate 1. The technical effect is also to achieve precise positioning during the assembly process, thereby ensuring welding quality and production automation efficiency. In battery assembly, the negative electrode tab 3 typically needs to be welded to the bottom of the battery casing or the bottom current collector. This second through hole provides a reliable mechanical positioning reference for automated equipment, ensuring that the negative electrode tab 3 is accurately aligned at the welding station. This is crucial for forming a stable, low-resistance electrical connection, effectively avoiding manufacturing defects such as incomplete or over-welded connections that may result from positioning deviations, thereby improving the overall safety and electrical performance consistency of the battery.

[0026] See Figures 1 to 3In one embodiment, the first through hole and / or the second through hole are circular holes. Specifically setting the first and / or second through holes used for positioning as circular holes is a technical feature based on a comprehensive consideration of mechanical fit, stress distribution, and manufacturing process. Its technical effects include improving positioning reliability, enhancing the mechanical strength of the tab, and simplifying the manufacturing process. From a mechanical fit perspective, a circular hole is the ideal fit shape for cylindrical locating pins widely used in industrial automation. This fit has an automatic centering effect, ensuring that the tab is precisely guided to the predetermined position regardless of the angle from which the locating pin is inserted. This provides extremely high precision and repeatability for subsequent welding processes, which is the foundation for ensuring consistency in large-scale production. In terms of mechanical strength, a circular hole effectively avoids stress concentration. Compared to other shapes with sharp corners (such as squares), the smooth circular contour evenly distributes the mechanical stress experienced by the tab during handling, bending, or use at the edge of the hole. This reduces the risk of cracks or tears in the tab at the hole opening, thereby improving the long-term reliability of the entire battery structure. Finally, from a manufacturing process perspective, the process of stamping or cutting circular holes is mature, inexpensive, and of stable quality. It is easy to achieve high-precision and high-efficiency mass production, which perfectly meets the needs of large-scale power battery manufacturing.

[0027] See Figures 1 to 3 In one embodiment, the positive electrode tab 6 has a first diameter-changing structure at the end away from the positive electrode sheet 4, and the first diameter-changing structure converges in the direction away from the positive electrode sheet 4. In this embodiment, the first diameter-changing structure at the end of the positive electrode tab 6 is specifically trapezoidal in shape. This structure can optimize the core winding and tab flattening process, solve the wrinkling problem caused by geometric deformation, and thus improve the subsequent welding yield and battery connection reliability. In the manufacturing process of cylindrical battery cores, when the tabs distributed on different levels are uniformly collected and flattened (i.e., flattened), they will converge inward due to the geometric relationship of the winding. If the tab is a simple rectangle, the outer tab will have more material accumulation than the inner tab due to its longer path, resulting in wrinkles and unevenness on the surface after flattening. This trapezoidal diameter-changing structure is designed to solve this problem. The converged shape provides a buffer space for material deformation when the tab converges inward, so that the tabs of all levels can be tightly and flatly attached together after being flattened to form a uniform welding surface. This effectively avoids problems such as incomplete soldering or weak welding caused by wrinkle stacking, and greatly improves the yield and quality of welding between the electrode tab and the collector plate.

[0028] See Figures 1 to 3In one embodiment, the negative electrode tab 3 has a second variable diameter structure at the end away from the negative electrode sheet 1, and the second variable diameter structure converges in the direction away from the negative electrode sheet 1. In this embodiment, the second variable diameter structure for the negative electrode tab 3 is also trapezoidal, and its technical effect is completely consistent with the design on the positive electrode side, aiming to solve the problem of stacking wrinkles caused by geometric deformation of the negative electrode tab 3 during winding and flattening. After the core is wound and formed, the negative electrode tabs 3 located at different winding radii will also experience inward convergence when they are uniformly collected and flattened. Without optimized design, the excess material of the outer tab will cause unevenness on the surface, directly affecting the welding quality with the battery casing or negative electrode current collector. By designing the negative electrode tab 3 as a trapezoid that converges in the direction away from the electrode sheet, buffering and accommodation space can be effectively provided for this material deformation. This allows all negative electrode tabs 3 to form a smooth, dense contact surface after being flattened, creating ideal conditions for subsequent laser welding. This ensures low resistance and high reliability of the negative electrode connection, avoiding safety hazards such as localized overheating that may result from poor welding. Therefore, using this variable diameter structure at both the positive and negative ends constitutes a symmetrical and complete solution, comprehensively improving the process stability of cylindrical batteries in key manufacturing stages and the quality of the final product.

[0029] See Figures 1 to 3 In one embodiment, the first and / or second variable diameter structures are trapezoidal structures. This embodiment explicitly defines the aforementioned variable diameter structure as a trapezoidal structure. As described above and in patent CN220138635U, after the cylindrical battery core is wound, its positive and negative tabs will experience material stacking due to the inward contraction effect when flattened. Designing the tabs as trapezoidal—that is, the bottom long side connects to the electrode sheet, and the top short side is away from the electrode sheet—is a compensatory design for this physical phenomenon. This trapezoidal structure can effectively accommodate the excess length of the outer tabs, avoiding wrinkles after flattening, thus forming a flat and dense welding surface. Its ultimate technical effect is a significant improvement in the yield of the tab-current collector welding, a reduction in contact resistance, and an enhancement of the long-term mechanical reliability of the connection, which is a key detail in ensuring the manufacturing quality of high-performance cylindrical batteries.

[0030] One embodiment of this utility model also provides a cylindrical battery, including the aforementioned battery core. This embodiment ultimately applies the battery core, integrating all the above-mentioned technical features, to a cylindrical battery, resulting in a systemic improvement in manufacturing efficiency, product performance, and long-term reliability. At the manufacturing level, by employing spaced welded tabs, the bottleneck problem of low liquid injection efficiency caused by traditional all-tab designs is fundamentally solved; while the circular positioning through-hole and trapezoidal variable-diameter structure at the end of the tabs jointly ensure high-precision positioning and flat compaction of the tab bundle during automated assembly, significantly improving the yield and production efficiency of key welding processes.

[0031] These optimizations in manufacturing processes ultimately translate into superior performance and reliability in the finished battery. Efficient and uniform electrolyte wetting ensures full utilization of active materials, laying the foundation for high capacity and long lifespan. High-quality, low-resistance welding connections ensure lower temperature rise and higher energy efficiency during high-current charging and discharging. Therefore, cylindrical batteries equipped with this battery core exhibit significant comprehensive advantages in energy density, rate performance, safety, and quality consistency, making them promising for applications in demanding fields such as new energy vehicles and energy storage.

[0032] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0033] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A battery core, comprising a positive electrode (4), a negative electrode (1), and a separator (7), characterized in that, The positive electrode sheet (4) is coated with a positive electrode paste (5) at the gaps. A positive electrode blank area is formed between the positive electrode pastes (5) for connecting the positive electrode tabs (6). The positive electrode tabs (6) are arranged on the positive electrode sheet (4) at intervals through the positive electrode blank area. The negative electrode sheet (1) is coated with a negative electrode paste (2) at the gaps. A negative electrode blank area is formed between the negative electrode pastes (2) for connecting the negative electrode tabs (3). The negative electrode tabs (3) are arranged on the negative electrode sheet (1) at intervals through the negative electrode blank area.

2. The battery core according to claim 1, characterized in that, The positive electrode tab (6) and the positive electrode plate (4) are welded together.

3. The battery core according to claim 1, characterized in that, The negative electrode tab (3) and the negative electrode sheet (1) are welded together.

4. The battery core according to claim 1, characterized in that, The positive electrode tab (6) has a first through hole at the end away from the positive electrode plate (4).

5. The battery core according to claim 4, characterized in that, The negative electrode tab (3) has a second through hole at the end away from the negative electrode plate (1).

6. The battery core according to claim 5, characterized in that, The first through hole and / or the second through hole are round holes.

7. The battery core according to claim 1, characterized in that, The positive electrode tab (6) is provided with a first variable diameter structure at the end away from the positive electrode plate (4), and the first variable diameter structure is converging in the direction away from the positive electrode plate (4).

8. The battery core according to claim 7, characterized in that, The negative electrode tab (3) is provided with a second variable diameter structure at the end away from the negative electrode plate (1), and the second variable diameter structure is converging in the direction away from the negative electrode plate (1).

9. The battery core according to claim 8, characterized in that, The first variable diameter structure and / or the second variable diameter structure are trapezoidal structures.

10. A cylindrical battery, characterized in that, Includes the battery core according to any one of claims 1-9.

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