Battery cell structure and single battery

Abstract

The invention discloses a battery cell structure and a single battery, the battery cell structure comprises a pole piece main body and a plurality of tabs, the pole piece main body comprises a starting end and a terminating end located in the length direction of the pole piece main body, the pole piece main body is used for winding to the terminating end by taking the starting end as a starting point to form the battery cell structure, and the plurality of tabs are arranged on the pole piece main body at intervals. The width of the tab close to the terminating end is greater than that of the tab close to the starting end; wherein when the pole piece main body is wound, the projection of the pole lug close to the starting end falls into the projection of the pole lug close to the ending end in the thickness direction perpendicular to the pole lugs, and the technical problem of pole lug dislocation caused by accumulated thickness deviation in the pole piece winding process is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery structures, and in particular to a battery core structure and a single battery. Background Art

[0002] With the widespread application of lithium-ion batteries in new energy vehicles, energy storage systems, and portable electronic devices, their manufacturing processes and structural design are attracting increasing attention. Among them, wound cells are widely used in cylindrical, pouch, and some prismatic batteries due to their high energy density and good processability. In the winding process, the positive electrode sheet, separator, and negative electrode sheet are stacked and wound together to form a "cell roll," which ultimately forms the basic energy storage unit of the battery.

[0003] During the winding process, the thickness errors between the various layers of pole pieces and separators gradually accumulate, forming what is known as "cumulative thickness deviation." This deviation can arise from factors such as uneven pole piece coating thickness, fluctuations in separator thickness, and unstable tension control. When the cumulative error reaches a certain level in the winding axial or radial directions, it can cause local asymmetry in the cell structure, leading to offset positions of the pole piece ends and, in turn, misalignment of the tabs during final molding.

[0004] Tab misalignment not only affects welding accuracy and consistency, but can also lead to abnormal connection resistance, poor welds, and even localized heating or safety hazards. Furthermore, tab misalignment can interfere with subsequent cell assembly and module connection processes, reducing finished product consistency and production yield. Therefore, controlling cumulative thickness deviation and improving tab alignment accuracy during the winding process has become a key technical issue in optimizing battery manufacturing processes. Summary of the Invention

[0005] An object of the present invention is to provide a battery cell structure and a single battery, which aims to solve the technical problem of tab misalignment caused by cumulative thickness deviation during the winding process of the electrode sheet.

[0006] To achieve the above-mentioned purpose, the present invention provides a solution: a battery cell structure, which includes a pole piece body, including a starting end and an ending end located in its length direction, and the pole piece body is used to be wound from the starting end to the ending end to form a battery cell structure; a plurality of pole ears are arranged at intervals on the pole piece body, and the width of the pole ear close to the ending end is greater than the width of the pole ear close to the starting end; wherein, when the pole piece body is wound, in the thickness direction perpendicular to the pole ear, the projection of the pole ear close to the starting end falls within the projection of the pole ear close to the ending end.

[0007] Optionally, the plurality of tabs are divided into a plurality of levels along the direction from the starting end to the ending end, the width of the tabs between different levels gradually increases, and the width of all tabs in the same level is the same.

[0008] Optionally, the width difference of the tabs between adjacent layers is d1, satisfying the relationship: 3 mm ≤ d1 ≤ 5 mm.

[0009] Optionally, each level includes the same number of tabs.

[0010] Optionally, the number of tabs included in each level gradually decreases from the starting end to the ending end.

[0011] Optionally, the width of the tab increases continuously and gradually from the starting end to the ending end; the difference between the tab width at the starting end and the tab width at the ending end is d2, which satisfies: 5㎜≤d2≤10㎜.

[0012] Optionally, from the starting end to the ending end, the width of the tab first increases continuously and gradually, and then remains unchanged at a fixed value; the difference between the tab width at the starting end and the fixed value is d3, satisfying: 5㎜≤d3≤8㎜.

[0013] Optionally, the distance between adjacent tabs gradually increases from the starting end to the ending end.

[0014] Optionally, the spacing increment S between adjacent tabs and the average thickness h of the pole piece body satisfy the relationship: S=Kh, where K is a compensation coefficient and satisfies 0.5≤K≤1.5.

[0015] To achieve the above object, the present invention further provides a solution: a single cell battery comprising the above cell structure.

[0016] The beneficial effects of the present invention are:

[0017] Compared to the existing technology in which the tabs cannot adapt to the positional offset caused by material thickness fluctuations and tension changes during the winding process, this application effectively improves the tab alignment tolerance by gradually increasing the tab width, especially by setting wider tabs near the terminal end. This allows the projection of the narrow and wide tab at the starting end to fall within the projection range of the wide tab at the terminal end, forming a clear and stable overlapping relationship, thereby improving the welding alignment accuracy between the tabs and reducing quality risks such as misalignment, crossover, and cold welding. This structure can achieve structural adaptive compensation for winding errors without relying on complex calibration mechanisms, significantly improving the manufacturing consistency and welding yield of battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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 use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0019] Figure 1 1 is a schematic diagram of an expanded battery cell structure provided by an embodiment of the present invention;

[0020] Figure 2 The embodiment of the present invention provides Figure 1 A partial enlarged view of area A in the middle;

[0021] Figure 3 The embodiment of the present invention provides Figure 1 A partial enlarged view of the middle B area;

[0022] Figure 4 It is a schematic diagram of another battery cell structure provided by an embodiment of the present invention.

[0023] Description of Figure Numbers:

[0024] 10. Pole body; 11. Starting end; 12. Ending end; 20. Pole ear; 31. First level; 32. Second level; 33. Third level. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship and movement status of the various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0027] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element through an intervening element.

[0028] See also Figures 1 to 3 , Figure 1 is a schematic diagram of an expanded battery cell structure provided by an embodiment of the present invention. Figure 2 The embodiment of the present invention provides Figure 1 A partial enlarged view of area A in the middle. Figure 3 The embodiment of the present invention provides Figure 1 A partial enlarged view of area B in the middle.

[0029] The present invention provides a battery cell structure for alleviating the misalignment of the tab 20 caused by winding errors. The distribution characteristics of the tab 20 width are adjusted to compensate for the cumulative thickness deviation during the winding process, thereby improving the consistency of the tab 20 alignment.

[0030] The cell structure includes a pole piece body 10 and multiple pole tabs 20. The pole piece body 10 is defined along its length by a starting end 11 and an ending end 12. During the winding process, the pole piece body 10 is continuously wound from the starting end 11 toward the ending end 12 to form a wound cell body with a certain thickness and number of layers. The pole piece body 10 can be made of a single polarity material or a bipolar laminated structure sandwiched between multiple layers of separators, making it suitable for the manufacturing requirements of soft-pack cells.

[0031] Multiple tabs 20 are spaced apart at the edge of the electrode body 10 and arranged along the length of the electrode. Each tab 20 extends from its corresponding electrode layer to provide a conductive connection between the battery cell and the external circuit. To effectively address cumulative thickness errors during the winding process, this embodiment specifies that the width of the tab 20 near the end end 12 is greater than the width of the tab 20 near the start end 11. This means that the width of the tab 20 gradually increases as its position on the electrode increases. Figure 2 and Figure 3 In FIG. 1 , L represents the original width of the tab 20 .

[0032] Since the pole piece is easily affected by factors such as material thickness fluctuations and tension changes during the winding process, the thickness error from the starting end 11 to the ending end 12 will continue to accumulate, causing the tab 20 near the ending end 12 to shift significantly during the final molding due to accumulated misalignment. Therefore, increasing the width of the tab 20 near the ending end 12 can provide a larger "alignment tolerance" in the direction perpendicular to the tab 20 (i.e., the winding thickness direction), thereby expanding the coverage of its projected profile, making it easier to achieve visual or welding alignment with the narrow and wide tab 20 of the previous layer.

[0033] Specifically, after the battery cell is wound, the projection of the tab 20 at the starting end 11 falls within the projection of the tab 20 at the ending end 12 in the thickness direction perpendicular to the direction of the tab 20, thereby ensuring a clear overlap between the tabs 20 at different levels. This overlap not only improves the alignment tolerance during subsequent welding or lead-out, but also reduces the probability of problems such as cold solder joints and poor overlap caused by misalignment of the tab 20. Through the above structure, without introducing complex process adjustments or additional calibration mechanisms, the position error of the tab 20 caused by winding can be compensated in a structural manner, thereby improving the manufacturing consistency and finished product yield of the battery cell, and further ensuring the electrical performance and reliability of the battery cell.

[0034] In some optimized embodiments, in order to more regularly control the distribution of the width of the tabs 20 and improve the alignment accuracy of the tabs 20 after the battery cell is wound, the multiple tabs 20 are divided into several levels along the length direction of the pole piece body 10, that is, from the starting end 11 to the ending end 12. Each level corresponds to a section of the pole piece area and includes several tabs 20.

[0035] Structurally, the width of the tabs 20 increases between different levels. That is, the tabs 20 in the levels near the end 12 are wider than those in the levels near the starting end 11, creating a segmented, gradual width distribution. Within the same level, all tabs 20 maintain a consistent width, avoiding the increased processing complexity and production tolerance fluctuations caused by frequent width switching.

[0036] In this embodiment, by adopting a hierarchical arrangement, the width adjustment of the tabs 20 is made more controllable, making it easier to match the specific requirements of different battery cell sizes, electrode thickness error ranges, and the number of winding layers by setting the specific number of layers and the number of tabs 20 per layer during process design. When the battery cell is wound, the tabs 20 of different layers form a progressive projection overlap relationship in the thickness direction, so that the entire array of tabs 20 presents a layer-by-layer inclusive and gradually increasing width arrangement. This arrangement can significantly alleviate the problem of tab 20 misalignment caused by the cumulative error of each layer, and improve the positioning reliability in the subsequent welding process.

[0037] In a further embodiment, the width difference of the tabs 20 between adjacent layers is set to a fixed value d1, which satisfies: 3 mm ≤ d1 ≤ 5 mm. Figure 2 and Figure 3 , Figure 3 The width of the tab 20 is relative to Figure 2 The width of the tab 20 in the embodiment is increased by d1, wherein, Figure 2 and Figure 3 The tabs 20 in the figure belong to adjacent levels.

[0038] If the width variation of the tab 20 is too small, for example, less than 3mm, manufacturing tolerances or cutting errors may result in unclear differences between layers, making it difficult to form an effective width progression relationship after actual winding, thereby weakening the ability to compensate for thickness deviations. If the width variation is too large, for example, exceeding 5mm, it may cause a sudden change in the structure of the tab 20, affecting the arrangement uniformity of the battery cell ends and even causing excessive accumulation in high-level areas, increasing the difficulty of subsequent module packaging and the risk of localized heat concentration.

[0039] In this embodiment, by controlling the width difference between 3 mm and 5 mm, it is possible not only to ensure that the tabs 20 of each level form a gradually widening projection relationship in the vertical thickness direction, thereby accommodating the misalignment of the tabs 20 caused by winding, but also to take into account the structural continuity and the stability of the manufacturing process, so that the tabs 20 have both error tolerance and will not cause adverse effects on processing.

[0040] In some embodiments, the number of tabs 20 included in each level is set to the same value. That is, in the process of dividing the tabs 20 from the starting end 11 to the ending end 12 into several levels, the same number of tabs 20 are evenly set in the length section of the pole piece allocated to each level. Figure 1 , Figure 1 The embodiment includes two levels, and the number of tabs 20 in the first level 31 and the second level 32 is the same.

[0041] On the one hand, equal-number layering facilitates rapid mapping between the tab 20 position and width and the electrode sheet expansion diagram in the early stages of design, facilitating standardized mold design and layout control, reducing tooling switching frequency, and improving manufacturing efficiency. On the other hand, during the winding process, since each layer contains a consistent number of tabs 20, the spatial increments corresponding to the changes in tab 20 width can form a periodic projection overlap in the thickness direction, thereby maintaining a high degree of alignment consistency and structural symmetry in the tab 20 area of ​​the entire battery cell.

[0042] Furthermore, equal-number layering facilitates compatibility with subsequent automated welding or inspection systems. For example, if each layer contains four tabs 20, then during cell welding layout, laser positioning, or quality inspection, template processing can be performed based on the same periodic arrangement, improving process adaptability and positioning accuracy while reducing equipment control complexity.

[0043] Additionally, see Figure 4 , Figure 4 is a schematic diagram of another battery cell structure provided by an embodiment of the present invention. In other embodiments, the hierarchical division method for controlling the width variation of the tab 20 is adjusted along the direction from the starting end 11 to the terminating end 12 of the electrode body 10: the number of tabs 20 included in each level gradually decreases, that is, the closer the level is to the terminating end 12, the fewer tabs 20 it contains, thereby achieving a gradually increasing frequency of the tab 20 width variation.

[0044] The core logic of this layout lies in the fact that the thickness deviation of the pole piece during the winding process is not uniformly distributed, but has a cumulative characteristic: the deviation is small in the first few turns, but as the number of winding layers increases, the material thickness fluctuations and tension disturbances are superimposed, the deviation will gradually increase. Therefore, near the starting end 11, the winding is stable and the error is low. Only a small number of layers and low-frequency adjustment of the pole tab 20 width are required to meet the alignment requirements; however, near the ending end 12, the error increases significantly. To achieve more precise deviation compensation, the pole tab 20 width needs to be adjusted more frequently, that is, shorter layers are set and the number of pole tabs 20 in each layer is reduced.

[0045] For example, if the entire electrode is divided into three levels, wherein the first level 31 includes four pole tabs 20, the second level 32 includes three pole tabs 20, and the third level 33 includes two pole tabs 20, the width of the pole tabs 20 within each level is consistent, and the width of the pole tabs 20 between levels is adjusted according to a set incremental increment, so that the thicker the winding position of the battery cell, the finer the adjustment of the width of the pole tab 20, which effectively improves the deviation adaptability and alignment accuracy.

[0046] In some optimized embodiments, the width of the tabs 20 no longer varies in a hierarchical, step-by-step manner, but rather adopts a continuous, gradual distribution. Specifically, the width of the tabs 20 increases gradually from the starting end 11 to the ending end 12, forming a smoothly varying width curve. Through this continuous gradual change, each tab 20 is slightly wider than the previous tab 20, achieving a higher adjustment frequency and more detailed error compensation capabilities, capable of accurately addressing the thickness deviations that accumulate during the winding process.

[0047] In this structure, the initial width of the tab 20 at the starting end 11 is smaller, while the width at the ending end 12 is larger to compensate for the positional deviation of the tab 20 caused by the increased thickness. The width difference between the tab 20 at the starting end 11 and the ending end 12 is defined as d2, and satisfies the requirement of 5 mm ≤ d2 ≤ 10 mm. While this minimum width difference of 5 mm provides effective alignment margin to accommodate deviations, a maximum width of no more than 10 mm prevents end accumulation, heat concentration, or structural interference caused by excessively wide tabs 20.

[0048] In this embodiment, by adopting a continuously gradient width distribution of the tabs 20, the battery cell structure achieves greater flexibility and adaptability in dealing with winding errors. The width of each tab 20 can be precisely controlled, ensuring nearly continuous overlap of the tab 20 projections in the thickness direction, effectively preventing quality issues such as tab 20 misalignment, crossover, or poor solder joints caused by winding deviations. This structure also avoids the discontinuous boundary issues caused by hierarchical division, improving the overall smoothness and processing consistency of the tab 20 arrangement, making it particularly suitable for battery cell structures requiring high precision and high consistency.

[0049] Furthermore, in some other embodiments, the width of the tab 20 varies along the electrode body 10 from the starting end 11 to the ending end 12 in a manner that "gradually changes in the front section and remains constant in the back section." Specifically, near the starting end 11, the width of each tab 20 increases continuously, forming a gradual width variation zone; after reaching a set threshold, the width of all subsequent tabs 20 remains fixed and no longer increases, forming a constant width zone.

[0050] The key consideration in the width distribution of this embodiment is that as the roll diameter increases, the marginal impact of each additional thickness difference on the thickness direction of the tab 20 gradually decreases. This is because a larger roll diameter reduces the amplitude of the perturbation of the unit thickness error at the projected position of the tab 20. Therefore, in the front section, due to the small roll diameter and sensitive position of the tab 20, it is suitable to improve the positioning tolerance through a higher-frequency width gradient. In the back section, although the cumulative deviation is larger, the perturbation amplitude of the additional error has stabilized. At this time, further increasing the width of the tab 20 will bring limited marginal benefits and may even lead to problems such as structural stacking and increased manufacturing complexity.

[0051] To achieve a balance between structure and process, the difference between the width of the tab 20 at the starting end 11 and the fixed width at the end is set to d3, satisfying the following conditions: 5 mm ≤ d3 ≤ 8 mm. This range allows the tab 20 to have sufficient width gradient in the beginning to compensate for the rapid accumulation of errors in the early stages, while maintaining a constant width in the end to avoid structural accumulation.

[0052] In some embodiments, see Figure 1 , Figure 1 Here, represents the original spacing between adjacent tabs 20. The spacing between adjacent tabs 20 gradually increases as the pole piece body 10 moves from the starting end 11 to the ending end 12. In other words, the tabs 20 are arranged with increasing spacing along the length of the pole piece, such that the distance between each pair of adjacent tabs 20 gradually increases as the winding process progresses.

[0053] The increase in spacing is based on the preset average thickness change during the winding process. By gradually increasing the spacing between the tabs 20 in the direction of the unfolded length of the pole piece, the error caused by the accumulated thickness is compensated, thereby reducing the risk of positioning deviation of the tabs 20. However, since the thickness error during the winding process is not absolutely uniform, there are often local fluctuations, such as instantaneous thickness changes caused by factors such as uneven coating of the pole piece, uneven thickness of the diaphragm, or tension fluctuations. For this reason, in this embodiment, the setting of gradually increasing the width of the tabs 20 is combined, that is, on the basis of gradually increasing the spacing, the width of the tabs 20 is also gradually increased in the winding direction. By combining the two, a layer of redundant tolerance is superimposed on the structural dimension. Even if local thickness fluctuations cause individual tabs 20 to have a slight deviation relative to the theoretical position, they can still be effectively contained in the thickness direction by virtue of the wider tabs 20.

[0054] In this embodiment, by combining the incremental increase in the spacing between the tabs 20 with the gradual change in the width of the tabs 20, the incremental increase in spacing is used to match the macroscopic variation trend of the overall thickness accumulation, while the increase in width is used to absorb the thickness fluctuations at the microscopic level, thereby significantly improving the alignment stability and manufacturing tolerance of the tabs 20 in the later stage of winding.

[0055] Furthermore, the spacing increment between adjacent tabs 20 is denoted as S, and the average thickness of the pole piece body 10 is denoted as h, which satisfies the following relationship: S=K·h, where K is a compensation coefficient, 0.5≤K≤1.5.

[0056] h represents the average effective thickness of the electrode during winding, typically including the combined average thickness of the positive and negative electrode bodies, double-sided coatings, and separators. It is a key parameter for measuring the rate of winding thickness growth. The spacing increment S represents the increase in the spacing between each pair of adjacent tabs 20 along the length of the electrode, used to match increasing thickness deviations.

[0057] K serves as a thickness fluctuation buffer adjustment factor, introducing structural redundancy into the spacing design to account for thickness variations across batches, operating conditions, or material systems. For production environments with relatively stable thickness control, K can be set close to 1 to achieve a compact layout. For winding structures with large thickness fluctuations, K can be set closer to 0.5 or 1.5 to enhance spacing tolerance and improve the anti-interference capabilities of the 20-tab arrangement.

[0058] The embodiment of the present invention further provides a single cell battery, which includes the battery cell structure described above to improve the structural stability of the battery.

[0059] The single cell can be in the form of a square aluminum shell battery, a soft-pack battery, or a cylindrical battery, and its core energy storage unit is the aforementioned wound cell structure. This cell structure effectively compensates for thickness errors generated during the winding process from a structural perspective by rationally configuring the arrangement of the tabs 20 in the length direction, including but not limited to a continuous gradient and segmented increase in the width of the tabs 20, and a layer-by-layer increase in the spacing between the tabs 20. Compared to traditional tab 20 structures, the cell of the present application has higher tab 20 overlap stability and alignment tolerance in the thickness direction.

[0060] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0061] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A battery cell structure, characterized in that: include: The pole piece body includes a starting end and an ending end in its length direction, and the pole piece body is used to be wound from the starting end to the ending end to form the battery cell structure; A plurality of tabs are spaced apart on the pole piece body, and the width of the tab near the terminating end is greater than the width of the tab near the starting end; When the pole piece body is wound, in a direction perpendicular to the thickness of the pole tab, the projection of the pole tab close to the starting end falls within the projection of the pole tab close to the ending end.

2. The battery cell structure according to claim 1, characterized in that: Along the direction from the starting end to the ending end, the plurality of tabs are divided into a plurality of levels, the width of the tabs between different levels gradually increases, and the width of all the tabs in the same level is the same.

3. The battery core structure according to claim 2, characterized in that: The width difference of the tabs between adjacent layers is d1, which satisfies the relationship: 3 mm ≤ d1 ≤ 5 mm.

4. The battery core structure according to claim 2, characterized in that: Each of the levels includes the same number of tabs.

5. The battery core structure according to claim 2, characterized in that: Along the direction from the starting end to the ending end, the number of the tabs included in each level gradually decreases.

6. The battery core structure according to claim 1, characterized in that: The width of the tab increases continuously and gradually from the starting end to the ending end; The difference between the width of the tab at the starting end and the width of the tab at the terminating end is d2, which satisfies: 5㎜≤d2≤10㎜.

7. The battery core structure according to claim 1, characterized in that: From the starting end to the ending end, the width of the tab first increases continuously and gradually, and then remains constant; The difference between the width of the tab at the starting end and the fixed value is d3, which satisfies: 5㎜≤d3≤8㎜.

8. The battery core structure according to any one of claims 1 to 7, characterized in that: From the starting end to the ending end, the distance between adjacent tabs gradually increases.

9. The battery core structure according to claim 8, characterized in that: The spacing increment S between adjacent pole tabs and the average thickness h of the pole piece body satisfy the relationship: S=Kh, where K is a compensation coefficient and satisfies 0.5≤K≤1.

5.

10. A single cell battery, characterized in that: The battery cell structure comprises the battery cell structure according to any one of claims 1 to 9.

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