Anti-precipitation lithium cathode plate and anti-precipitation lithium battery

Abstract

The utility model provides an anti-precipitation lithium cathode piece and anti-precipitation lithium battery, including cathode current collector and cathode active material layer, the cathode active material layer is provided on the cathode current collector, the cathode current collector includes the bending section and the straight section, the part of the cathode current collector located in the bending area is the bending section, and the straight section is the straight section. The part, located in the straight area, of the cathode current collector is a straight section, the bent section and the straight section are alternately arranged in the first direction, the first direction is the extending direction of the cathode piece, the bent section comprises an inner concave surface and an outer convex surface which are opposite to each other, the inner concave surface faces the interior of the winding cell and is provided with a cathode active material layer, and the outer convex surface faces the interior of the winding cell. The outer convex surface faces the outer part of the winding cell and is provided with a cathode active material layer, the cathode current collector comprises a body and a bulge, at least one of the transition region, the outer convex surface and the inner concave surface is provided with the bulge, the bulge protrudes along a second direction relative to the body, and the second direction is the thickness direction of the anti-precipitation lithium cathode plate. And lithium precipitation in the bending area of the battery cell can be effectively avoided.

Description

Technical Field

[0001] This utility model relates to the field of new energy technology, and in particular to an anti-lithium plating cathode sheet and an anti-lithium plating battery. Background Technology

[0002] With continuous technological advancements and innovation, the demand for various smart devices, especially smartphones and computers, is growing daily. The widespread adoption of these devices has led to higher requirements for the performance and safety of smart products. Among numerous performance indicators, energy density and safety have become the focus of attention for both consumers and manufacturers. To meet these demands, higher coating weights and compaction are employed, posing increasing challenges to the charging capacity of the system and making batteries more prone to lithium plating. This is especially true in the bending areas of the electrodes, where lithium plating is more likely to occur. In wound battery cells, after the positive and negative electrodes and separator are stacked, they need to be wound to form the cell. During the charging and discharging process, towards the later stages of cycling, the electrodes in the bending section, primarily the anode electrodes, expand from the inner to the outer ring of the cell. This causes the electrolyte between the electrodes to be squeezed out and lost, resulting in insufficient lithium-ion kinetics and making lithium plating more likely. Secondly, the bending deformation in the bending section leads to either insufficient anode active material or excessive cathode active material, further contributing to lithium plating. Therefore, a new battery design is needed to prevent lithium plating in the bending areas. Utility Model Content

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an anti-lithium-plating cathode sheet, which can effectively prevent lithium plating from occurring in the bending areas of the battery cell.

[0004] This utility model also proposes an anti-lithium plating battery.

[0005] According to a first aspect of the present invention, an anti-lithium plating cathode sheet is used to manufacture a wound battery cell. The wound battery cell includes an anti-lithium plating cathode sheet, a separator, and an anode sheet. The anti-lithium plating cathode sheet, the separator, and the anode sheet are sequentially stacked and wound to form a wound battery cell. The wound battery cell includes a bending region and a straight region. The anti-lithium plating cathode sheet, the separator, and the anode sheet have a bending arc in the bending region, and the anti-lithium plating cathode sheet, the separator, and the anode sheet are planar in the straight region. The anti-lithium plating cathode sheet includes a cathode current collector and a cathode active material layer. The cathode active material layer is disposed on the cathode current collector. The cathode current collector includes a bent section and a straight section. The portion of the cathode current collector located in the bending region is the bent section. The curved section, wherein the portion of the cathode current collector located in the straight region is the straight section, the curved section and the straight section are alternately arranged along the first direction, the first direction being the direction in which the anti-lithium plating cathode sheet extends, the curved section includes an inner concave surface and an outer convex surface facing away from each other, the inner concave surface facing the inside of the wound cell and having a cathode active material layer disposed thereon, the outer convex surface facing the outside of the wound cell and having a cathode active material layer disposed thereon, a transition region is provided on the straight section connecting the two ends of the curved section, the cathode current collector includes a body and a protrusion, at least one of the transition region, the outer convex surface and the inner concave surface is provided with the protrusion, the protrusion protruding relative to the body along a second direction, the second direction being the thickness direction of the anti-lithium plating cathode sheet.

[0006] The lithium plating-resistant cathode sheet according to the first aspect of the present invention has at least the following beneficial effects: by providing protrusions on the curved section with a bending arc, the mass of cathode active material at the curved section and / or transition region of the cathode current collector is reduced, the CB value of the curved section is increased, thereby reducing the number of lithium ions that need to be embedded in the curved section. At the same time, the protrusions on the curved section and the protrusions in the transition region can also resist the outward expansion of the electrode sheet, reduce the leakage of electrolyte between the electrodes by compression, thereby effectively avoiding the lithium plating phenomenon caused by compression in the curved area of ​​the wound cell.

[0007] According to some embodiments of the present invention, the current collector includes a first layer and a second layer, the second layer covering the first layer to form the coating surface, and the first layer is provided with protrusions to form protrusions on the coating surface.

[0008] According to some embodiments of the present invention, the first layer is an insulating layer and the second layer is a conductive layer.

[0009] According to some embodiments of this utility model, the area on the straight section where the distance between the straight section and the curved section is no more than 10mm is the transition area.

[0010] According to some embodiments of the present invention, the protrusion array is disposed on the transition region, the concave surface and the convex surface, and the height of the protrusion in the second direction is not less than 1 μm and not more than 200 μm.

[0011] According to some embodiments of the present invention, the interval between the protrusions in the first direction is not less than 0.5 mm, the interval between the protrusions in the third direction is not less than 0.5 mm, and the third direction is the width direction of the cathode current collector.

[0012] According to some embodiments of the present invention, the height of the protrusion in the second direction does not exceed the height of the cathode active material layer in the second direction.

[0013] According to some embodiments of the present invention, in the first direction, the interval between the protrusions on the concave surface is greater than the interval between the protrusions on the convex surface.

[0014] According to some embodiments of the present invention, both the concave surface and the convex surface are provided with protrusions, and the protrusions on the concave surface and the protrusions on the convex surface are staggered along the first direction.

[0015] The lithium-plating-resistant battery according to a second aspect of the present invention includes the lithium-plating-resistant cathode sheet described in any of the above embodiments.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the cell structure of a lithium plating-resistant cathode sheet according to the present invention;

[0018] Figure 2 This is a schematic diagram of the bent and straight sections of the cathode current collector in an anti-lithium plating cathode sheet according to the present invention.

[0019] Figure 3 This is a schematic diagram of the front structure of the cathode current collector on an anti-lithium plating cathode sheet according to the present invention;

[0020] Figure 4 This is a schematic cross-sectional view of the anti-lithium plating cathode sheet in the bending region according to the present invention;

[0021] Figure 5 This is a schematic diagram of the internal structure of the cathode current collector of an anti-lithium plating cathode sheet according to the present invention.

[0022] Icon labels:

[0023] 1. Cathode current collector; 11. Bending section; 111. Concave surface; 112. Convex surface; 12. Straight section; 13. Body; 14. Protrusion; 15. Insulator; 16. Conductive layer; 17. Transition region; 21. Bending region; 22. Straight region; 3. Cathode active material layer. Detailed Implementation

[0024] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0025] In the description of this utility model, it should be understood that the orientation descriptions, such as up and down, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] In the description of this utility model, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features or their sequential relationship.

[0027] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0028] In the battery manufacturing process, the anode, cathode, and separator need to be stacked. After stacking and pressing, they are wound to form a wound cell. During the charging and discharging of the electrodes, the outward expansion of the electrodes creates internal stress at the bending points. This causes the active material layer to be subjected to greater compressive force at the bending points, resulting in less electrolyte at the bending points. At the same time, the bending deformation reduces the lithium intercalation kinetics in the bending area, making lithium plating more likely to occur at the bending points.

[0029] Reference Figure 1 , Figure 2 , Figure 3 and Figure 4The lithium-plating-resistant cathode sheet in the first embodiment of this utility model is used to manufacture a wound battery cell. The wound battery cell includes: a lithium-plating-resistant cathode sheet, a separator, and an anode sheet. The lithium-plating-resistant cathode sheet, separator, and anode sheet are stacked and wound sequentially to form the wound battery cell. The wound battery cell includes a bending region 21 and a straight region 22. The lithium-plating-resistant cathode sheet, separator, and anode sheet have a bending arc in the bending region 21, and the lithium-plating-resistant cathode sheet, separator, and anode sheet are flat in the straight region 22. The bending region 21 of the wound battery cell is located at both ends of the straight region 22, so that the middle section of the wound battery cell is flat, while the two ends are curved.

[0030] The lithium plating-resistant cathode sheet includes a cathode current collector 1 and a cathode active material layer 3. The cathode active material layer 3 is disposed on the cathode current collector 1. The cathode current collector 1 includes a bent section 11 and a straight section 12. The portion of the cathode current collector 1 located in the bent region 21 is the bent section 11, and the portion of the cathode current collector 1 located in the straight region 22 is the straight section 12. The bent section 11 and the straight section 12 are alternately arranged along a first direction, which is the direction in which the lithium plating-resistant cathode sheet extends. A portion of the lithium plating-resistant cathode sheet is located in the straight region 22 of the wound cell, where the lithium plating-resistant cathode sheet is straight, and the portion of the cathode current collector 1 located in this region is the straight section 12. A portion of the lithium plating-resistant cathode sheet is also located in the bent region 21 of the wound cell, where the lithium plating-resistant cathode sheet is curved, and the portion of the cathode current collector 1 located in this region is the bent section. Furthermore, the bent section and the straight section 12 of the cathode current collector 1 are alternately arranged along the winding direction of the current collector, and compression will occur between the bent section of the cathode current collector 1 and the anode plate.

[0031] The curved section 11 includes a concave surface 111 and a convex surface 112 facing each other. The concave surface 111 faces the inside of the wound cell and is provided with a cathode active material layer 3. The convex surface 112 faces the outside of the wound cell and is also provided with a cathode active material layer 3. The cathode current collector 1 includes a body 13 and a protrusion 14. A transition region 17 is provided on the straight section 12 connecting the two ends of the curved section 11. At least one of the transition region 17, the convex surface 112, and the concave surface 111 is provided with a protrusion 14. The protrusion 14 protrudes relative to the body 13 along a second direction, which is the thickness direction of the anti-lithium plating cathode sheet. Due to the arc-shaped bend in the curved section 11 of the cathode current collector 1, the concave surface 111 and the convex surface 112 facing each other will appear. Both the concave surface 111 and the convex surface 112 will experience compression, and the compression between the concave surface 111 and the anode sheet will be more severe. The protrusion 14 is provided in the bending section 11 to reduce the cathode active material on the bending section 11, thereby effectively avoiding lithium plating in the bending section 11. In addition, the protrusion 14 can also increase the contact area between the cathode current collector 1 and the cathode active material layer 3, thereby reducing the internal resistance of the cell.

[0032] The protrusions 14 on the surface of the cathode current collector 1 can be of various types, including metal protrusions, conductive colloid protrusions, and conductive polymer protrusions. The structure of the protrusions 14 on the cathode current collector 1 can be obtained by modifying the morphology of the intermediate layer of a composite current collector, or by applying metal spraying, dispensing / drip coating, coating, and drying to the metal layer on the surface of the cathode current collector 1. When setting the protrusions 14, they can be directly set on the body 13 of the cathode current collector 1, and their shape can be adjusted after setting. When the protrusions 14 are metal protrusions, they can also be obtained by stamping to achieve the desired shape of the cathode current collector 1. The structure of the protrusions 14 on the cathode current collector 1 can be obtained by modifying the morphology of the intermediate insulating layer of a composite current collector, or by applying metal spraying, dispensing / drip coating, coating, and drying to the conductive layer 16 on the surface of the cathode current collector 1 to obtain metal protrusions, colloid protrusions, conductive polymer protrusions, etc. The cathode current collector 1 features pre-set metal protrusions 14, which enhance conductivity and resistance to deformation. Protrusions containing colloidal materials, such as conductive adhesive protrusions, offer advantages such as better plasticity, ductility, and flexibility compared to metal protrusions. They are also less prone to overpressure of the active material in the protruding areas during rolling. Furthermore, the conductive adhesive, due to the principle of organic similarity solubility and its ease of forming porous structures, can increase liquid retention. This further prevents lithium plating.

[0033] According to some embodiments of this utility model, refer to Figure 5 The cathode current collector 1 includes an insulator 15 and a conductive layer 16. The conductive layer 16 wraps around the insulator 15 to form the cathode current collector 1. Protrusions are provided on the insulator 15 to form protrusions 14 on the bent section 11. In the prior art, there are composite current collectors, which include an insulating layer and a conductive layer 16. The conductive layer 16 is disposed on both sides of the insulating layer to form a conductive current collector. The conductive layer 16 can also be disposed on one side of the insulating layer. Electroplating, deposition, or other methods can be used to dispose of the conductive layer 16 on the insulating layer. The insulator 15 is typically a thin film, which allows for a smaller thickness of the cathode current collector 1. The first layer can also be a metal layer or an alloy conductive layer, thereby improving the overall structural strength of the current collector.

[0034] Composite current collectors in battery cells not only significantly improve battery performance but also demonstrate numerous advantages in practical applications. First, by employing lightweight and highly conductive materials, composite current collectors significantly reduce the overall weight of the battery, crucial for applications such as portable electronic devices and electric vehicles. This material allows the battery to maintain high energy density while providing longer driving range and more efficient energy utilization. Second, the mechanical strength and flexibility of composite current collectors are significantly enhanced. This not only helps maintain the structural integrity of the battery under impact or pressure but also improves the battery's cycle stability under different temperature and environmental conditions, thereby extending battery life. Furthermore, the design flexibility of composite current collectors allows engineers to customize current collectors with specific surface properties based on different electrode materials and battery design requirements, optimizing electrode material adhesion and battery charge / discharge performance. Finally, the use of composite current collectors effectively reduces the battery's internal resistance, meaning the battery can operate more efficiently during charge and discharge, reducing energy loss and providing stronger power output and faster charging speeds. In conclusion, composite current collectors are playing an increasingly important role in battery technology. They not only improve battery performance but also open up new possibilities for innovative battery design and applications.

[0035] According to some embodiments of this utility model, the area on the straight section where the distance between it and the curved section does not exceed 10mm is the transition region 17. During battery cycling, the anode expands and deforms, compressing the cathode. Due to the high stress and easy electrolyte loss in the transition region, lithium intercalation is poor, leading to lithium plating. Therefore, it is necessary to set a protrusion on the straight section close to the curved section to effectively prevent lithium plating in the transition region.

[0036] According to some embodiments of this utility model, the array of protrusions 14 is disposed on the transition region 17, the concave surface 111, and the convex surface 112. The height of the protrusions 14 in the second direction is not less than 1 μm and not more than 200 μm. The spacing between the protrusions 14 in the first direction is not less than 0.5 mm, and the spacing between the protrusions 14 in the third direction is not less than 0.5 mm, where the third direction is the width direction of the cathode current collector 1. When the spacing between the protrusions 14 is too small, it is difficult to place the active material into the gaps between the protrusions 14 when the cathode active material is disposed on the cathode current collector 1 to form the cathode active material layer 3, which will lead to the formation of bubbles in the active material layer. Therefore, the spacing between the protrusions 14 in the first direction and the spacing between the protrusions 14 in the third direction are both limited to not less than 0.5 mm so that the active material can be fully filled into the gaps between the protrusions 14.

[0037] The formation of air bubbles in the active material layer of a battery is a significant problem. These tiny air pockets not only interfere with internal chemical reactions but also severely impact overall battery performance. When bubbles form in the active material layer, they occupy valuable space, reducing the effective contact area between the active material and the electrolyte. This reduction in contact area directly leads to a decrease in battery charging and discharging efficiency, thus affecting the battery's output power and range. Worse still, bubble accumulation can cause abnormal increases in internal battery pressure. As pressure increases, the battery casing may expand, and in extreme cases, even rupture. This physical damage not only shortens battery life but can also pose safety hazards. In some extreme cases, the continuous accumulation of bubbles can even trigger internal short circuits, leading to overheating and even the risk of combustion or explosion. Therefore, engineers must take a series of measures to prevent and reduce bubble formation during battery design and manufacturing. This includes optimizing battery manufacturing processes, ensuring uniform material mixing, and strictly controlling environmental conditions during battery assembly. Through these meticulous efforts, the negative impacts of bubbles can be significantly reduced, thereby ensuring battery performance and safety.

[0038] According to some embodiments of this utility model, the height of the protrusion 14 in the second direction does not exceed the height of the cathode active material layer 3 in the second direction. When the height of the protrusion 14 in the second direction exceeds the height of the cathode active material layer 3 in the second direction, the protrusion 14 will be exposed. This may damage the separator, leading to an internal short circuit in the battery, or cause compression between the protrusion and the electrode, resulting in a decrease in the energy density of the battery. Therefore, it is necessary to limit the height of the protrusion 14 in the second direction to not exceeding the height of the cathode active material layer 3 in the second direction.

[0039] According to some embodiments of the present invention, in the first direction, the spacing between the protrusions 14 on the concave surface 111 is greater than the spacing between the protrusions 14 on the convex surface 112. When the bent section is bent, the gap between the protrusions 14 on the concave surface 111 in the first direction will decrease due to the bending effect, while the spacing between the protrusions 14 on the convex surface 112 in the first direction will increase. Therefore, in order to avoid the gap between the protrusions 14 on the concave surface 111 being too small or causing interference after the cathode current collector 1 is bent, and the spacing between the protrusions 14 on the convex surface 112 being too large, the spacing between the protrusions 14 on the concave surface 111 is made greater than the spacing between the protrusions 14 on the convex surface 112.

[0040] According to some embodiments of this utility model, both the concave surface 111 and the convex surface 112 are provided with protrusions 14, and the protrusions 14 on the concave surface 111 and the convex surface 112 are staggered along a first direction. By staggering the protrusions 14 on the concave surface 111 and the convex surface 112 along the first direction, stress concentration in the cathode current collector 1 is avoided during bending, thereby improving the structural strength of the cathode current collector 1.

[0041] The lithium-plating-resistant battery according to a second aspect of the present invention includes a lithium-plating-resistant cathode sheet according to any one of the above embodiments.

[0042] The energy density of a battery cell refers to the energy that can be stored per unit volume or unit mass of the cell. It is usually expressed in watt-hours per liter (Wh / L) for volumetric energy density and in watt-hours per kilogram (Wh / kg) for gravimetric energy density. Higher energy density means the cell can store more electrical energy per unit volume or mass, which is crucial for applications such as portable electronic devices and electric vehicles. How is the energy density of a battery cell calculated? The energy density of a battery cell, i.e., the energy stored per unit volume or unit mass of the battery, is one of the key indicators for measuring battery performance. It is influenced by a variety of complex factors, spanning a wide range of fields from materials science to engineering design. First, the chemical composition of the cell is the core factor affecting energy density. Different cathode materials, such as lithium cobalt oxide (LiCoO2), lithium nickel cobalt manganese oxide (NCM), or lithium iron phosphate (LFP), have different energy storage capacities. Anode materials, such as graphite or silicon-based materials, also affect the overall energy density due to their different electrochemical properties. The choice of electrolyte and the material of the separator are equally important, as they determine the efficiency and safety of ion transport within the battery. Design and manufacturing processes are also crucial factors affecting energy density. The battery's structural design, including electrode thickness, active material loading, and packaging method, significantly impacts energy density. For example, thinner electrodes reduce the use of inactive materials, thus increasing energy density per unit volume. The precision of the manufacturing process, such as coating uniformity, compaction density, and assembly accuracy, all affect battery performance. Furthermore, material quality and purity also have a significant impact on energy density. High-purity materials reduce internal side reactions and improve energy utilization. The microstructure of materials, such as particle size and distribution, also affects the surface area of ​​electrode materials and ion diffusion paths, thereby influencing the battery's charge and discharge performance.

[0043] Lithium plating in batteries refers to the uneven deposition of lithium ions on the surface of the negative electrode during battery charging, eventually forming lithium metal dendrites. The appearance of these dendrites poses a significant threat to the health of the battery. First, from a safety perspective, the growth of lithium dendrites is a double-edged sword. It can not only pierce the battery's internal separator, causing direct contact between the positive and negative electrodes, but this contact often has catastrophic consequences. Once a short circuit occurs, the internal temperature of the battery will rise sharply, triggering a series of chain reactions, potentially leading to overheating, expansion, or even fire and explosion, posing a significant safety hazard to users. Second, the battery's lifespan will be significantly reduced due to the formation of lithium dendrites. The continuous growth of lithium dendrites consumes the battery's precious lithium-ion resources. As the number of lithium ions decreases, the number of rechargeable cycles and the battery's capacity will gradually decline. Users will find that a battery that could have lasted for several years may experience significant performance degradation in a very short time. Furthermore, the battery's charging and discharging efficiency will also be severely affected. The formation of lithium dendrites increases the internal resistance of the battery, making the flow of electrons within the battery less smooth. This increased resistance not only reduces charging speed but also affects power output during discharge, thus lowering the overall battery performance. Finally, the stability of battery performance is also affected by the uneven growth of lithium dendrites. The growth of lithium dendrites can lead to voltage instability during battery use. These voltage fluctuations directly affect the devices powered by the battery, causing them to operate unstably or even shut down unexpectedly. Therefore, lithium plating is a phenomenon that must be strictly controlled and avoided in the design and use of lithium-ion batteries. Battery manufacturers and researchers have been working to reduce or eliminate lithium dendrite formation by improving battery materials, optimizing battery structure, and optimizing charging strategies to ensure battery safety, extend its lifespan, and maintain its performance stability and reliability.

[0044] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A lithium precipitation-preventing cathode sheet for manufacturing a jelly-roll battery cell, the jelly-roll battery cell comprising: A lithium precipitation-preventing cathode sheet, a separator, and an anode sheet are sequentially stacked and wound into a wound battery cell, the wound battery cell includes a bending region and a flat region, the lithium precipitation-preventing cathode sheet, the separator, and the anode sheet have a bending curvature in the bending region, and the lithium precipitation-preventing cathode sheet, the separator, and the anode sheet are flat in the flat region. The lithium precipitation-preventing cathode sheet includes a cathode current collector and a cathode active material layer, the cathode active material layer is arranged on the cathode current collector, the cathode current collector includes a bending section and a flat section, a part of the cathode current collector in the bending region is the bending section, a part of the cathode current collector in the flat region is the flat section, the bending section and the flat section are alternately arranged along a first direction, the first direction is a direction in which the lithium precipitation-preventing cathode sheet extends, the bending section includes an inner concave surface and an outer convex surface facing away from each other, the inner concave surface faces an inside of the wound battery cell and is provided with the cathode active material layer, the outer convex surface faces an outside of the wound battery cell and is provided with the cathode active material layer, two ends of the flat section connecting the bending section are provided with a transition region, the cathode current collector includes a body and a protrusion, at least one of the transition region, the outer convex surface, and the inner concave surface is provided with the protrusion, the protrusion protrudes in a second direction relative to the body, the second direction is a thickness direction of the lithium precipitation-preventing cathode sheet.

2. The lithium plating prevention cathode sheet according to claim 1, characterized by The current collector includes a first layer and a second layer, the second layer is arranged on the first layer to form a coated surface, and the first layer is provided with a bump to form a protrusion on the coated surface.

3. The lithium plating prevention cathode sheet according to claim 2, characterized by The first layer is an insulating layer, and the second layer is a conductive layer.

4. The lithium plating prevention cathode sheet according to claim 1, characterized by, A region on the flat section with a distance of no more than 10 mm from the bending section is the transition region.

5. The lithium plating prevention cathode sheet according to claim 1, characterized by The array of protrusions is arranged on the transition region, the inner concave surface, and the outer convex surface, and a height of the protrusion protruding in the second direction is no less than 1 μm and no more than 200 μm.

6. The lithium plating prevention cathode sheet according to claim 5, characterized by An interval of the protrusions in the first direction is no less than 0.5 mm, and an interval of the protrusions in a third direction is no less than 0.5 mm, the third direction being a width direction of the cathode current collector.

7. The lithium plating prevention cathode sheet according to claim 5, characterized by The height of the protrusion in the second direction is no more than a height of the cathode active material layer in the second direction.

8. The lithium plating prevention cathode sheet according to claim 6, characterized by In the first direction, an interval between the protrusions on the inner concave surface is greater than an interval between the protrusions on the outer convex surface.

9. The lithium plating prevention cathode sheet according to claim 1, characterized by, The inner concave surface and the outer convex surface are both provided with protrusions, and the protrusions on the inner concave surface and the protrusions on the outer convex surface are staggered along the first direction.

10. A lithium precipitation preventing battery, characterized by The lithium precipitation-preventing cathode sheet includes a cathode current collector and a cathode active material layer, the cathode active material layer is arranged on the cathode current collector, the cathode current collector includes a bending section and a flat section, a part of the cathode current collector in the bending region is the bending section, a part of the cathode current collector in the flat region is the flat section, the bending section and the flat section are alternately arranged along a first direction, the first direction is a direction in which the lithium precipitation-preventing cathode sheet extends, the bending section includes an inner concave surface and an outer convex surface facing away from each other, the inner concave surface faces an inside of the wound battery cell and is provided with the cathode active material layer, the outer convex surface faces an outside of the wound battery cell and is provided with the cathode active material layer, two ends of the flat section connecting the bending section are provided with a transition region, the cathode current collector includes a body and a protrusion, at least one of the transition region, the outer convex surface, and the inner concave surface is provided with the protrusion, the protrusion protrudes in a second direction relative to the body, the second direction is a thickness direction of the lithium precipitation-preventing cathode sheet.

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