A core wrap structure and a single battery

Abstract

The application discloses a core package structure and a single battery. The core package structure comprises a core package body, a tab and a coating. The tab is connected to the core package body. An end of the tab away from the core package body is provided with a cutting surface formed by cutting. The coating covers the cutting surface and is used for covering metal burrs generated by cutting. The application aims to solve the technical problem of burr and wire drawing metal foreign matter falling off after cutting of the tab.

Description

Technical Field

[0001] This application relates to the field of battery cell structure technology, and in particular to a cell pack structure and a single battery cell. Background Technology

[0002] As a crucial structure for both internal current convergence and external current extraction within a battery cell, the quality of the tab's processing directly impacts the cell's electrical and safety performance. Currently, the most widely used tab processing methods are mechanical cutting, such as die-cutting, punching, or laser cutting. However, during tab cutting, due to the inherent ductility of the metal material and the limitations of the cutting method, irregular metal debris such as burrs, wire drawing, and edge chipping is easily generated on the cut end face of the tab. These tiny metal foreign objects often adhere to the tab edges or hang on its surface, posing a potential risk of detachment.

[0003] During subsequent assembly, these metallic foreign objects may detach from the electrode surface and enter the internal structure of the battery cell due to disturbances caused by processes such as vibration, hot pressing, and liquid injection. Once embedded in the electrode gaps or separator area, these foreign objects may form micro-short circuit paths locally, causing continuous weak self-discharge of the battery cell, thereby affecting the cell's capacity retention and cycle life. More seriously, short circuits caused by foreign objects may accumulate local heat during charging and discharging, triggering thermal runaway reactions, leading to cell swelling, smoke, or even explosion, posing serious safety hazards.

[0004] Therefore, how to avoid the risk of detachment caused by burrs and wires or other metallic foreign objects after the tabs are cut has become an urgent technical problem to be solved. Utility Model Content

[0005] One objective of this application is to provide a core pack structure and a single cell that aims to solve the technical problem of burrs and wires falling off metal foreign objects after the tabs are cut.

[0006] To achieve the above objectives, this application provides a solution as follows: a core package structure, the core package structure including a core package body; a tab connected to the core package body, the end of the tab away from the core package body having a cut surface formed by cutting; and a coating covering the cut surface for covering the metal burrs generated during cutting.

[0007] Optionally, the coating includes a main area and a flow edge area, with the main area covering the cut surface and the flow edge area extending from the main area to the side of the tab.

[0008] Optionally, the thickness of the main body area is d1, which satisfies: 0.5mm≤d1≤1mm.

[0009] Optionally, the length of the region covering the side of the electrode tab in the flow edge region is t, which satisfies: 0.3mm≤t≤0.6mm.

[0010] Optionally, the coating is a hot melt adhesive, which forms the main body area and the flow edge area covering the cut surface through melting and flow.

[0011] Optionally, the electrode tab also includes a welding surface, with its two opposite ends connected to the cutting surface and the core package body, respectively. The welding surface is provided with a pre-welding area. When the pre-welding area is spaced apart from the cutting surface, the distance between the cutting surface and the pre-welding area is d2, satisfying: 0≤d2≤4mm; or when the pre-welding area is connected to the cutting surface, the distance between the edge of the pre-welding area away from the cutting surface and the cutting surface is d3, satisfying: 3mm≤d3≤8mm.

[0012] Optionally, the tab includes multiple layers of current collectors, which are stacked to form the tab, and the number of current collector layers is at least 40.

[0013] Optionally, the width of the current collector decreases first and then tends to be constant along the direction from the core body to the cut surface.

[0014] Optionally, the central axes of the multilayer current collectors are collinear in the tab width direction.

[0015] Optionally, the coating is an insulating layer.

[0016] To achieve the above objectives, one solution provided in this application is: a single-cell battery, which includes the aforementioned core pack structure and housing, wherein the core pack structure is disposed within the housing.

[0017] The beneficial effects of this application are as follows: Compared to existing technologies that rely on passive control measures such as cleaning the tab ends, filtering metal shavings, and enhancing cleanliness to reduce the risk of metal foreign object detachment, this application introduces a coating into the tab cutting surface and its edge areas to actively seal and retain burrs, wires, and other metal micro-shavings generated during the cutting process, thus suppressing the possibility of foreign object detachment. The coating possesses excellent insulation, corrosion resistance, and electrolyte stability, not only constructing a physical isolation barrier but also blocking potential electrical contact paths, effectively preventing local short circuits or self-discharge problems caused by metal foreign objects. Furthermore, the coating passivates and buffers the tab edges, further enhancing the tab ends' resistance to mechanical disturbances and improving the overall safety and stability of the cell structure. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application 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 application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1This is an overall schematic diagram of a core-packing structure provided in an embodiment of this application; Figure 2 This is provided by the embodiments of this application. Figure 1 A magnified view of a portion of region A in the middle; Figure 3 This is a partially enlarged view of another core-encapsulation structure provided in the embodiments of this application; Figure 4 This is a side view of a core-encapsulation structure provided in an embodiment of this application; Figure 5 This is provided by the embodiments of this application. Figure 4 A magnified view of a portion of region B in the middle.

[0020] Explanation of icon numbers: 10. Core package body; 20. Electrode tab; 21. Cutting surface; 22. Welding surface; 221. Pre-welding area; 23. Current collector; 30. Coating; 31. Body area; 32. Flow edge area. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0023] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.

[0024] Please see Figure 1 and Figure 2 , Figure 1 This is an overall schematic diagram of a core-packing structure provided in an embodiment of this application. Figure 2 This is provided by the embodiments of this application. Figure 1 A magnified view of a portion of region A in the middle.

[0025] This application provides a core-packing structure to address the problem that burrs, wires, and other metallic foreign objects generated after the tabs 20 are cut can easily fall off and enter the battery cell, thereby improving the overall structural safety of the battery cell. The core-packing structure mainly includes a core-packing body 10, multiple tabs 20, and a coating 30 disposed at the ends of the tabs 20.

[0026] The core package body 10 is the core functional part of the battery cell. It preferably adopts a wound or stacked structure, which is composed of positive electrode plates, negative electrode plates and separators stacked alternately. The core package body 10 is connected to corresponding tabs 20. The tabs 20 can be led out from the same side or opposite side of the core package body 10 to form a symmetrical or asymmetrical arrangement.

[0027] The tab 20 extends perpendicularly to the plane of the core package body 10 or at an angle for subsequent connection to the busbar, sampling plate, or housing lead-out end. The tab 20 is typically made of aluminum, nickel, or nickel-plated copper to meet the requirements of low impedance and structural flexibility. The end of the tab 20 is cut to a predetermined length during processing. The cut surface 21 is the exposed terminal structure. Conventional processes such as mechanical shearing, stamping, die cutting, and laser cutting can easily form burrs, wires, micro-shavings, and other metal microstructures at the cut edge under high-speed and high-frequency processing. These residual structures are easily detached due to stress disturbance or fluid erosion during subsequent processes such as cell packaging, electrolyte injection, and activation, and then fall into the core package, posing a short circuit hazard.

[0028] Therefore, this application provides a coating 30 in the cut surface 21 area of ​​the tab 20. Specifically, the coating 30 covers the entire cut end face of the tab 20 and the side edge extending from that end face towards the substrate of the tab 20, forming a closed encapsulation structure. The coating 30 can be in the form of liquid coating and curing, hot melt encapsulation, molding encapsulation, etc., and the material can be epoxy resin, polyimide, fluorosilicone rubber, polyolefin hot melt adhesive, etc., possessing excellent insulation, corrosion resistance and electrolyte stability.

[0029] In this embodiment, by providing a coating 30 in the cutting surface 21 area of ​​the tab 20, the present application seals and structurally holds in minute metal foreign objects such as burrs and wires generated during the cutting process, effectively preventing these foreign objects from falling off due to mechanical disturbance or liquid erosion in subsequent manufacturing stages. This coating structure not only forms a continuous and dense protective layer geometrically, but also possesses excellent electrical insulation and chemical stability. It can effectively block the electrical contact path between metal burrs and other potential structures while ensuring that conductivity is not affected, thereby avoiding cell failure phenomena such as local short circuits, self-discharge, or heat accumulation caused by foreign object embedding.

[0030] Furthermore, the coating 30, by edge-wrapping and shape-passivating the ends of the tabs 20, also plays an auxiliary role in eliminating stress concentration and improving mechanical anti-interference capabilities. Compared to traditional solutions that rely on post-processing cleaning, filtration, or enhanced cleanliness control to reduce the risk of metal foreign objects, this structure is a pre-processing elimination solution. It is simple to implement, highly adaptable, and can be carried out without relying on high-precision processing equipment.

[0031] Furthermore, in some optimized embodiments, to enhance the coating effect of the coating 30 on the burrs at the cut portion of the tab 20, and to improve the mechanical stability and durability of the structure, the coating 30 specifically includes two functional areas: a main body area 31 and a flow edge area 32. The main body area 31 mainly covers the cut end face of the tab 20, that is, the exposed surface formed after the metal material is physically cut. This area is usually where the micro-defects such as metal burrs and wire drawing are most concentrated. The coating of the main body area 31 can effectively fill, wrap, and electrically isolate the burr structure, preventing it from being directly exposed to the air or electrolyte environment.

[0032] The flow edge region 32 is formed by the natural extension of the main body region 31 towards the thickness direction of the tab 20, covering the side wall area or edge transition area adjacent to the cut end of the tab 20. The presence of the flow edge region 32 not only makes the coating 30 geometrically continuous, avoiding sharp transitions or void accumulation between the end face and the side face, but also plays a role in edge passivation and stress diffusion, reducing the risk of coating peeling caused by subsequent hot pressing, welding or vibration.

[0033] The extension length of the flow edge region 32 can be adjusted according to the size of the tab 20 and the burr distribution characteristics to ensure sufficient edge protection coverage without affecting the normal electrical connection or welding fit between the tab 20 and the external connection structure. In addition, the edge of the flow edge region 32 can be set as a rounded corner or a gradient transition structure to enhance the adhesion and compliance between the coating and the metal substrate.

[0034] Please see Figure 2 , Figure 2 This is provided by the embodiments of this application. Figure 1 A partial enlarged view of region A in the middle. While retaining the main structural framework of the above embodiments, some embodiments further limit the dimensional parameters of the coating 30 to better balance the ability to cover the burrs of the tab 20, structural stability, and adaptability to subsequent processes, ensuring that the coating 30 meets functional requirements without adversely affecting the core packaging assembly, electrical connection, or heat treatment processes.

[0035] Specifically, in this embodiment, the main body area 31 of the coating 30 is disposed on the cut end face of the tab 20, and its thickness is d1, preferably satisfying the following range: 0.5mm≤d1≤1mm. The lower limit of this thickness range (0.5mm) ensures that the coating has sufficient coverage depth to completely cover the metal burrs, wires, and pit structures formed by the cutting process, effectively preventing foreign matter from falling off and electrical exposure; while the upper limit (1mm) avoids excessive structural protrusions caused by excessive coating thickness, which may affect the fit or welding reliability between the tab 20 and external connecting components (such as busbars, electrode clamps, etc.). In addition, the coating controlled within this thickness range is also conducive to achieving uniform curing, reducing internal stress concentration, and improving overall adhesion strength and long-term durability.

[0036] Simultaneously, the coating 30 naturally extends along the edge of the tab 20 to form a flow edge region 32, which covers the sidewall area adjacent to the cut surface 21 of the tab 20, thereby further enhancing the edge sealing effect. The coverage length of this flow edge region 32 on the side of the tab 20 is defined as t, preferably satisfying: 0.3mm ≤ t ≤ 0.6mm. This extension length is sufficient to cover secondary burrs and microcracks that are usually distributed at the end edges, while avoiding interference with the spatial layout of the area where the tab 20 is located or interference with other structural components due to excessive coverage. Especially in the compact internal environment of the module, reasonable control of the length of the flow edge region 32 can effectively avoid problems such as assembly interference, coating peeling, or edge curling caused by excessive coating overlap.

[0037] In this embodiment, by setting the functional partitions and size boundaries of the coating 30, this application constructs a stable and efficient electrical safety barrier in structure, ultimately achieving the technical effects of improving the terminal insulation of the tab 20, preventing metal foreign object contamination, and enhancing the internal safety and reliability of the core package.

[0038] In one implementation, the coating 30 is made of hot melt adhesive material. Hot melt adhesive is solid at room temperature and has good dielectric properties and chemical stability. It can be transformed into a molten state with a certain degree of fluidity after being heated to a specific temperature, and has excellent filling and encapsulating properties. In this embodiment, the hot melt adhesive is applied to the cut end of the tab 20 through a hot melt device, and naturally extends through its own fluidity and capillary action in the heated molten state to form a main body area 31 covering the cut surface 21, and a flow edge area 32 extending along the cut edge towards the side of the tab 20.

[0039] The main area 31 is formed by the preferential deposition and spreading of molten hot melt adhesive on the cut end face of the tab 20. This effectively fills irregular structures such as metal burrs and wire-drawing depressions formed during the cutting process, sealing the exposed metal surface and forming a continuous and dense insulating barrier. Later in the coating process, as the hot melt adhesive flows along the edges and cools naturally, some of the material extends further along the edge of the cut surface 21 towards the side of the tab 20 and solidifies, forming the flow edge area 32. This creates a corner-enclosing structure in the three-dimensional structure, transitioning from the end face to the edge. This transition structure not only improves the integrity of the coverage of edge burrs but also achieves a rounded transition in the mechanical structure, reducing the probability of stress concentration points and enhancing the coating's anti-peeling ability and structural stability.

[0040] Furthermore, using hot melt adhesive as the coating material 30 offers significant process advantages. The processing requires no solvents or additional curing agents, making it environmentally friendly. In industrial production, it can be applied efficiently and with high precision through various methods such as hot melt spraying, molding, and hot-pressing roller coating, making it suitable for large-scale automated production. Simultaneously, a wide variety of hot melt adhesive materials are available, and their glass transition temperature, softening point, adhesion properties, and heat resistance can be customized according to the tab 20 material and the battery cell's operating environment, thereby meeting the diverse requirements of different battery cell products for heat resistance, electrolyte stability, and thickness control.

[0041] Please see Figure 2 and Figure 3 , Figure 2 This is provided by the embodiments of this application. Figure 1 A magnified view of a portion of region A in the middle. Figure 3 This is a partially enlarged view of another core-packing structure provided in an embodiment of this application. In some other embodiments, in order to balance the stability of the lead-out structure of the tab 20 with the compatibility of subsequent welding processes, the tab 20 structure is further refined to include a welding surface 22. This welding surface 22 is the area used for electrical connection with the busbar, sampling plate, or external connection terminal, and is usually a flat metal surface to facilitate the efficient implementation of welding processes such as laser welding, ultrasonic welding, or resistance welding.

[0042] Specifically, the two ends of the welding surface 22 are connected to the cutting surface 21 of the electrode tab 20 and the core package body 10, respectively. The welding surface 22 may have a pre-welding area 221, which is used to guide the positioning of the weld point or improve the welding quality, depending on the welding structure. The relative relationship between the pre-welding area 221 and the cutting surface 21 can be divided into two cases: The first scenario involves a certain distance between the pre-welded area 221 and the cut surface 21, meaning the pre-welded area 221 is not directly in contact with the cut surface 21. In this structure, the pre-welded area 221 is positioned back, which helps to keep the welding heat source away from the cut end where metal burrs exist, reducing the impact of heat conduction on the coating 30 or the covered area. In this case, the distance between the cut surface 21 and the pre-welded area 221 is d2, preferably satisfying: 0 ≤ d2 ≤ 4 mm. A lower limit of 0 mm indicates that the pre-welded area 221 is adjacent to the cut surface 21, suitable for compact structures; while an upper limit of 4 mm ensures sufficient isolation distance to provide a thermal buffer zone, preventing the coating 30 at the cut from melting, bubbling, or peeling during the high-temperature welding process.

[0043] The second scenario involves the pre-welding area 221 being directly connected to the cut surface 21. In this structure, although the cut end is the starting point of the weld, a certain welding buffer length still needs to be reserved to ensure uniform heat diffusion and welding reliability. Therefore, the length between the edge of the pre-welding area 221 away from the cut surface 21 and the cut surface 21 is defined as d3, preferably satisfying: 3mm ≤ d3 ≤ 8mm. Within this range, the lower limit of d3 ensures an effective unfolded length of the welding surface 22 to support the weld joint, while the upper limit of d3 avoids material waste or structural wiring interference caused by an excessively long welding area.

[0044] Please see Figure 4 and Figure 5 , Figure 4 This is a side view of a core-encapsulation structure provided in an embodiment of this application. Figure 5 This is provided by the embodiments of this application. Figure 4 A magnified view of region B in the middle. In some optimized embodiments, to improve the current carrying capacity of the tab 20 and reduce resistance loss, the tab 20 structure is designed as a multi-layer current collector 23 stacked structure. The tab 20 is composed of multiple metal current collector 23 unit sheets stacked together, piled and pressed along the thickness direction to form an integrated tab 20 structure, which has higher structural density and electrical performance compared to the traditional single-piece or multi-strand parallel tab 20 structure.

[0045] The current collector 23 is preferably a highly conductive metal material, such as nickel-plated copper foil, pure nickel sheet, or aluminum foil, with a thickness of 10μm to 30μm and a width comparable to that of a single-layer tab 20. Through multi-layer stacking, each layer can be effectively bonded using ultrasonic welding, thermocompression bonding, or high-temperature diffusion welding to ensure minimal overall resistance and avoid uneven current distribution or localized heating due to poor interface conditions.

[0046] In this structure, the current collector 23 has at least 40 layers, meaning that the total number of metal conductors stacked along the thickness direction in the tab 20 is not less than 40 layers, mainly to meet the requirements for current carrying capacity. As the number of current collector 23 layers increases, the total thickness can be controlled within a reasonable range by controlling the ratio between the thickness of a single layer and the total stack thickness, so as to balance structural flexibility and mechanical strength.

[0047] In this embodiment, by adopting the tab 20 structure of the multilayer current collector 23, the resistance value per unit length of the tab 20 can be significantly reduced and the overall conductivity can be improved. Secondly, the bonding interface between the multilayer metals also has a certain mechanical buffering effect, which is conducive to absorbing the structural stress during the thermal expansion and contraction of the battery cell and improving the reliability of the connection between the tab 20 and the core package.

[0048] Furthermore, to improve the bending resistance of the tab 20, in some optimized embodiments, the width arrangement structure of the current collector 23 in the tab 20 is specially designed. The tab 20 is composed of multiple layers of metal current collector 23 stacked together. The length and thickness of each current collector 23 layer are consistent, but its width gradually decreases from one end of the core body 10 to the end of the tab 20 cut surface 21, until the width at the end region tends to be constant. As a result, the tab 20 forms a geometric shape that gradually shrinks from bottom to top in the cross-section perpendicular to its length direction, and the overall cross-section presents an "inverted T-shaped" contour feature.

[0049] In this embodiment, by setting a wider current collector 23 layer near the core package connection, the metal coverage width at the root of the tab 20 is increased, thereby effectively improving the bending stiffness and structural stability of this area. In practical applications, the tab 20 often faces repeated bending or displacement disturbances applied by processes such as hot pressing, welding, and module assembly. If its root rigidity is insufficient, it is prone to plastic deformation or metal fatigue. By adopting an inverted T-shaped cross-section structure, the wide bottom area can provide good structural support, significantly enhancing bending resistance and reducing the risk of permanent deformation of the tab 20 under stress.

[0050] Meanwhile, the relatively constant width of the end current collector 23 helps maintain the dimensional consistency of the tab 20, facilitating subsequent automated welding, insulation coating, and other processes, thus improving process stability and batch consistency. Furthermore, the progressively decreasing width transition provides a natural and flexible visual and structural transition, reducing localized stress concentration and enhancing the long-term reliability of the tab 20 under dynamic loads.

[0051] As one implementation method, based on the above structure, in order to improve the overall stability of the tab 20 structure, the arrangement of the multilayer current collectors 23 in the width direction of the tab 20 adopts an axisymmetric design. The central axes of all current collector layers 23 coincide with each other in the width direction, that is, they are evenly distributed along the center line of the tab 20 width direction, ensuring that each layer of current collectors 23 is centered and aligned in the width direction, so that the geometry of the tab 20 in the cross-section presents a symmetrical structure and the overall outline remains symmetrical from left to right.

[0052] The symmetrical arrangement of the tabs 20 in the width direction helps to achieve uniform current distribution, avoiding electrical hazards such as uneven resistance and concentrated current density caused by local current collector 23 misalignment, and improving the electrical reliability of the tabs 20 in high-rate charging and discharging scenarios. Secondly, the symmetrical structure also allows the tabs 20 to achieve better mechanical balance under stress, reducing structural warping or torsion caused by uneven loads. In particular, alignment is easier to control during module assembly and hot pressing, which is beneficial to improving the assembly accuracy and consistency of the entire package.

[0053] This application also provides a single-cell battery, which includes a core pack structure according to any of the above embodiments and a housing for encapsulation and protection, wherein the core pack structure is disposed within the internal space of the housing. The core pack structure and the housing can be fixed together by certain limiting structures, cushioning materials or adhesive media to prevent the core pack from shaking, colliding or misaligning during transportation and use.

[0054] In this embodiment, by integrating the core-pack structure with burr-covered structure into the battery casing, the electrical connection reliability of the tab 20 can be maintained while effectively suppressing internal micro-short circuit problems caused by burr shedding, thereby improving the structural integrity and safety performance of the single battery cell.

[0055] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0056] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the content of this application's specification and drawings under the concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A core-encapsulation structure, characterized in that, include: Core package body; A tab is connected to the core package body, and the end of the tab away from the core package body has a cut surface formed by cutting. A coating is applied to the cut surface to cover the metal burrs produced during cutting.

2. The core-encasing structure according to claim 1, characterized in that, The coating includes a main area and a flow edge area, the main area covering the cut surface, and the flow edge area extending from the main area to the side of the tab.

3. The core-encasing structure according to claim 2, characterized in that, The thickness of the main body area is d1, which satisfies: 0.5mm≤d1≤1mm.

4. The core-encasing structure according to claim 2, characterized in that, The length of the area covered by the flow edge region on the side of the electrode tab is t, which satisfies: 0.3mm≤t≤0.6mm.

5. The core-encasing structure according to any one of claims 2 to 4, characterized in that, The coating is a hot melt adhesive, which melts and flows to form the main body area and the flow edge area covering the cut surface.

6. The core-encasing structure according to claim 1, characterized in that, The electrode tab also includes a welding surface, the two opposite ends of which are respectively connected to the cutting surface and the core package body, and the welding surface is provided with a pre-welding area; When the pre-welded area is spaced from the cutting surface, the distance between the cutting surface and the pre-welded area is d2, satisfying: 0 ≤ d2 ≤ 4 mm; or When the pre-welded area is connected to the cutting surface, the distance between the edge of the pre-welded area away from the cutting surface and the cutting surface is d3, which satisfies: 3mm≤d3≤8mm.

7. The core-encasing structure according to claim 1, characterized in that, The electrode tab includes multiple layers of current collectors, which are stacked to form the electrode tab, and the number of current collector layers is at least 40.

8. The core-encasing structure according to claim 7, characterized in that, The width of the current collector decreases first and then tends to be constant along the direction from the core body to the cut surface.

9. The core-encasing structure according to claim 8, characterized in that, The central axes of the multilayer current collectors are collinear in the width direction of the tabs.

10. The core-encasing structure according to any one of claims 1 to 9, characterized in that, The coating is an insulating layer.

11. A single-cell battery, comprising a core pack structure and a housing as described in any one of claims 1 to 9, wherein the core pack structure is disposed within the housing.

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