Negative electrode sheet and preparation method therefor, cylindrical battery, and electronic cigarette

Abstract

The present invention provides a negative electrode sheet, which uses pure silicon particles as a negative electrode active material. By controlling the mass proportion of the pure silicon particles in the silicon-based negative electrode active material and adjusting the areal density and compacted density of the negative electrode sheet, the thickness of a coating layer on the negative electrode sheet is controlled, thereby improving the energy density and electrical conductivity of the negative electrode sheet. The present invention further provides a preparation method for the negative electrode sheet. The viscosity and solid content of a slurry are controlled by selecting a preferred conductive agent and binder, thereby realizing the preparation of the negative electrode sheet. The present invention further provides a cylindrical battery using the negative electrode sheet. By changing the width and length of the positive and negative electrode sheets, various types of high-energy-density cylindrical batteries can be prepared, and the batteries also have excellent rate capability.

Description

A negative electrode sheet, its preparation method, a cylindrical battery, and an electronic cigarette.

[0001] This application claims priority to Chinese Patent Application No. CN202510040934.6, filed on January 10, 2025, entitled "A negative electrode sheet, its preparation method and cylindrical battery, electronic cigarette", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of battery technology, and in particular to a negative electrode sheet, its preparation method, a cylindrical battery, and an electronic cigarette. Background Technology

[0003] Lithium-ion batteries, with their high energy density, long cycle life, and small volume-to-weight ratio, have become the ideal power source for portable electronic devices such as e-cigarettes. In recent years, with the continuous development of the e-cigarette market, consumers' expectations for e-cigarettes have also been constantly evolving, not only pursuing long battery life but also desiring a refined and rich flavor experience. Against this backdrop, high-energy-density and high-rate lithium-ion batteries, as a core element in enhancing the overall e-cigarette experience, have seen their market demand continue to rise, becoming a major driving force for the e-cigarette industry's development.

[0004] The high state of energy (SEE) of lithium-ion batteries for e-cigarettes is a crucial factor determining their lifespan. High-energy-density batteries can provide more energy within the same volume and weight, thus extending the e-cigarette's usage time. The high rate performance of lithium-ion batteries is also a significant factor influencing the user experience. High-rate batteries can provide higher discharge currents, supporting the efficient operation of the e-cigarette atomizer, producing more vapor and a better flavor. However, the energy density and rate performance of lithium-ion batteries are affected by multiple factors, including electrode materials, cell electrode design, and manufacturing processes. Therefore, in pursuit of high-energy-density and high-rate e-cigarette lithium-ion batteries, manufacturers are constantly exploring new battery materials and manufacturing processes, driving continuous updates and iterations in e-cigarette products.

[0005] For example, Chinese patent application CN111342005B discloses a method for preparing a lithium-ion battery for electronic cigarettes. Its positive electrode uses high-voltage, high-compact lithium cobalt oxide, with an antioxidant coating. The negative electrode uses silicon-carbon material, combined with an optimized electrolyte formulation, thus achieving the preparation of a high-voltage, high-energy-density, and high-rate lithium-ion battery for electronic cigarettes. However, this method uses a composite material of silicon-carbon and graphite as the negative electrode active material, and the specific capacity of the negative electrode material is only about 500 mAh / g at most, which cannot achieve higher energy density. Another example is a method for preparing an ultra-large diameter cylindrical electronic cigarette battery disclosed in Chinese patent application CN118738292A. Its positive electrode uses high-rate-performance lithium cobalt oxide and a rate-type ternary composite material, combined with graphite as the negative electrode. The battery capacity is increased by controlling the positive electrode ratio, areal density, and compaction density; simultaneously, a highly conductive agent is selected to increase the proportion of the active main material, thereby achieving the goal of improving the battery's volumetric energy density and rate performance. However, its negative electrode uses graphite, which has a theoretical capacity of only 374mAh / g, limiting the battery's energy density.

[0006] Therefore, effectively improving the energy density and rate performance of lithium-ion batteries for e-cigarettes requires comprehensive consideration of electrode materials and electrode design. Silicon materials, with a theoretical capacity of 4200 mAh / g, have already been applied in anode materials, such as silicon-based, silicon-oxygenated, and silicon-carbon high-capacity materials. However, the addition of large amounts of carbon diminishes the high capacity of silicon, failing to meet the demand for higher energy densities. Summary of the Invention

[0007] The purpose of this invention is to provide a negative electrode sheet, its preparation method, a cylindrical battery, and an electronic cigarette. The negative electrode sheet of this invention uses pure silicon particles as the negative electrode material, which has extremely high specific capacity and can significantly improve the energy density of the battery. At the same time, by controlling the coating thickness of the negative electrode sheet, a thinner design of the negative electrode sheet is achieved, which shortens the migration distance of electrons and ions, which is beneficial to reducing the internal resistance of the battery and improving the rate performance of the battery.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, the present invention provides a negative electrode sheet, comprising a negative electrode current collector, a negative electrode tab disposed on the negative electrode current collector, and a negative electrode silicon-based active material;

[0010] The negative electrode silicon-based active material includes pure silicon particles, and the pure silicon particles have a mass percentage content of 65-100% in the negative electrode silicon-based active material.

[0011] The negative electrode silicon-based active material forms a first coating surface and a second coating surface on the upper and lower surfaces of the negative electrode current collector, respectively, and the sum of the thickness of the first coating surface and the second coating surface is 12μm-20μm;

[0012] In one embodiment, the specific capacity of the pure silicon particles is ≥3200mAh / g.

[0013] In one embodiment, the average particle size of the pure silicon particles is 3.0-6.0 μm.

[0014] In one embodiment, the bifacial areal density of the negative electrode sheet is 1.6-2.4 mg / cm³. 2 .

[0015] In one embodiment, the compaction density of the negative electrode sheet is 1.1-1.3 g / cm³. 3 .

[0016] In one embodiment, the thickness of the negative electrode sheet is 18μm-28μm.

[0017] In one embodiment, the first coating surface and the second coating surface each include two negative electrode coating areas, and the negative electrode tab is welded in a first blank area between the two negative electrode coating areas of the first coating surface, or the negative electrode tab is welded in a second blank area between the two negative electrode coating areas of the second coating surface.

[0018] In one embodiment, the distance between the two coated areas is 2-8 times the width of the negative electrode tab.

[0019] In one embodiment, the welding area between the negative electrode tab and the negative electrode sheet is greater than 8 mm². 2 .

[0020] The beneficial effects of the negative electrode sheet provided by this invention are as follows: by selecting high-specific-capacity, easily manufactured micron-sized silicon particles as the main negative electrode material, not only can the production cost of the main negative electrode material be effectively reduced, but the requirement for high volumetric energy density can also be met. Simultaneously, by controlling the areal density and compaction density of the negative electrode sheet to regulate the thickness of the micron-sized silicon particles on the negative electrode current collector, while ensuring the lithium storage capacity of the negative electrode sheet, the thickness of the coating layer of the negative electrode sheet is reduced, thus reducing the migration distance of lithium ions during charging and discharging. This helps to improve the migration resistance of lithium ions during charging and discharging, reduce the internal resistance of the negative electrode sheet, achieve the purpose of increasing current, and improve the conductivity of the negative electrode sheet.

[0021] Secondly, the present invention also provides a method for preparing the above-mentioned negative electrode sheet, comprising the following steps:

[0022] A: Pure silicon particle material, conductive agent and binder are evenly dispersed in solvent to obtain negative electrode coating slurry. The solid content of the negative electrode coating slurry is 10-15wt%, and the viscosity of the negative electrode coating slurry is 4000-15000mPa·s.

[0023] B: The negative electrode coating slurry is coated on the surface of the current collector, and the negative electrode sheet is obtained after drying and rolling.

[0024] The beneficial effects of the method for preparing a negative electrode sheet provided by this invention are as follows:

[0025] This invention increases the total specific surface area of ​​all particles in the slurry by using various conductive agents with high specific surface area, combined with a binder system with good thickening effect, and optimizes the mixing sequence to ensure the fluidity and stability of the slurry. This ensures the uniformity and consistency of the coating even when the negative electrode is coated thinly, avoiding scratches and uneven thickness.

[0026] Thirdly, the present invention also provides a cylindrical battery, comprising an aluminum-plastic shell, an electrolyte disposed within the shell, and a cylindrical core, wherein the cylindrical core comprises a positive electrode, a separator, and the aforementioned negative electrode.

[0027] In one embodiment, the positive electrode sheet includes a positive current collector, a positive electrode tab disposed on the positive current collector, and a positive active material, wherein the positive active material is one of lithium manganese oxide or lithium cobalt oxide.

[0028] In one embodiment, the positive electrode active material is lithium cobalt oxide, and the proportion of lithium cobalt oxide in the positive electrode active material is 80-100 wt%.

[0029] In one embodiment, the lithium cobalt oxide has an average particle size of 4.5-6.0 μm.

[0030] In one embodiment, the positive electrode active material is characterized in that a third coating surface and a fourth coating surface are formed on the upper and lower surfaces of the positive electrode current collector, respectively; the third coating surface and the fourth coating surface each include two positive electrode coating areas, and the positive electrode tab is welded in a third blank area between the two positive electrode coating areas of the third coating surface, or the positive electrode tab is welded in a fourth blank area between the two positive electrode coating areas of the fourth coating surface.

[0031] In one embodiment, the positive electrode has a length of 745-750 mm and a width of 20-25 mm; the negative electrode has a length of 800-805 mm and a width of 20-25 mm; and the cylindrical battery has a capacity of 580-700 mAh at a discharge rate of 0.2C.

[0032] In one embodiment, the positive electrode has a length of 745-750 mm and a width of 25-30 mm; the negative electrode has a length of 800-805 mm and a width of 25-30 mm; and the cylindrical battery has a capacity of 710-810 mAh at a discharge rate of 0.2C.

[0033] In one embodiment, the positive electrode has a length of 745-750 mm and a width of 30-35 mm; the negative electrode has a length of 800-805 mm and a width of 30-35 mm; and the cylindrical battery has a capacity of 820-920 mAh at a discharge rate of 0.2C.

[0034] In one embodiment, the positive electrode has a length of 1300-1320 mm and a width of 25-35 mm; the negative electrode has a length of 1360-1380 mm and a width of 25-35 mm; and the cylindrical battery has a capacity of 1000-1600 mAh at a discharge rate of 0.2C.

[0035] In one embodiment, the positive electrode has a length of 1300-1320 mm and a width of 40-45 mm; the negative electrode has a length of 1360-1380 mm and a width of 40-45 mm; and the cylindrical battery has a capacity of 2100-2400 mAh at a discharge rate of 0.2C.

[0036] In one embodiment, the positive electrode has a length of 1300-1320 mm and a width of 50-55 mm; the negative electrode has a length of 1360-1380 mm and a width of 50-55 mm; and the cylindrical battery has a capacity of 2500-2900 mAh at a discharge rate of 0.2C.

[0037] The beneficial effects of the cylindrical battery provided by this invention are as follows: Using the aforementioned negative electrode sheet with pure silicon particles as the negative electrode material fully leverages the high-capacity characteristics of silicon, significantly improving the battery's capacity. By optimizing the electrode sheet manufacturing process, high-rate discharge characteristics are also achieved, enhancing the overall performance of the cylindrical battery. This meets the market's urgent demand for high-efficiency, high-capacity, safe, and reliable battery products, demonstrating broad market application prospects and social value. Furthermore, the aforementioned negative electrode sheet can meet the design requirements of cylindrical batteries of different sizes and can be customized according to the needs of different electronic devices. It is widely used in portable electronic devices, electric vehicles, energy storage systems, and many other fields, showcasing broad applicability and market competitiveness.

[0038] Fourthly, the present invention also provides an electronic cigarette, including the aforementioned cylindrical battery.

[0039] The beneficial effects of the electronic cigarette provided by the present invention are as follows: by using the above-mentioned cylindrical battery, the electronic cigarette can be provided with a longer battery life, meeting the user's demand for high performance and long standby time, and improving the user's experience. Attached Figure Description

[0040] Figure 1 is a schematic diagram of the structure of the first coating surface of the negative electrode current collector of a negative electrode sheet provided by the present invention;

[0041] Figure 2 is a schematic diagram of the structure of the second coating surface of the negative electrode current collector of a negative electrode sheet provided by the present invention;

[0042] Figure 3 is a side view of the negative current collector of a negative electrode sheet provided by the present invention;

[0043] Figure 4 is a schematic diagram of the third coating surface of the positive current collector of a positive electrode sheet provided by the present invention;

[0044] Figure 5 is a schematic diagram of the fourth coating surface of the positive current collector of a positive electrode sheet provided by the present invention;

[0045] Figure 6 is a side view of the positive current collector of a positive electrode sheet provided by the present invention;

[0046] Figure 7 is a schematic diagram of the structure of a cylindrical battery provided by the present invention;

[0047] Explanation of reference numerals in the attached drawings: 100, cylindrical battery; 10, negative electrode; 20, positive electrode; 30, separator; 40, aluminum-plastic shell; 11, negative current collector; 111, first coated surface; 111A, first coated area; 111B, second coated area; 111C, first blank area; 112, second coated surface; 112A, third coated area; 112B, fourth coated area; 112C, second blank area; 113, first side edge; 114, second side edge; 12, negative electrode tab; 121, first conductive sheet; 121A, first ultrasonic solder mark; 122, first insulating sheet; 123, second insulating sheet; 21, positive current collector; 211, third coated surface; 211A, fifth coated area; 211B, sixth coated area; 211C, third blank area; 212, Fourth coating surface; 212A, Seventh coating area; 212B, Eighth coating area; 212C, Fourth blank area; 213, Third side; 214, Fourth side; 22, Positive electrode tab; 221, Second conductive sheet; 221A, Second ultrasonic solder mark; 222, Third insulating sheet; 223, Fourth insulating sheet. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0050] The "scope" disclosed in this invention is defined by a lower limit and an upper limit. A given scope is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific scope. This method of defining a scope includes endpoints and allows for arbitrary combinations; that is, any lower limit can be combined with any upper limit to form a scope.

[0051] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0052] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.

[0053] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially.

[0054] With the increasing demand for higher energy density and shorter charging times in lithium-ion batteries, the theoretical capacity of graphite anodes (374 mAh / g) is gradually limiting the development of batteries towards higher energy density. Silicon anodes, with their high theoretical capacity, are considered the most promising anode material for high-energy-density lithium-ion batteries. Compared to nano-silicon, micron-sized silicon has lower raw material costs, higher tap density, and smaller surface area, offering advantages in improving volumetric energy density and limiting interfacial side reactions. Therefore, the inventors of this application selected high-specific-capacity micron-sized pure silicon as the anode active material. By controlling the areal density and tap density of the anode sheet 10, the thickness of the anode sheet 10 can be controlled to minimize its thickness, reducing the migration distance of lithium ions during charging and discharging, improving the migration resistance of lithium ions during charging and discharging, enhancing the conductivity of the anode sheet 10, and ultimately improving the energy density and rate performance of the lithium-ion battery.

[0055] Figures 1-3 show schematic diagrams of a negative electrode sheet 10 provided by this invention. In this invention, the length direction of the negative electrode sheet 10 is defined as X, its width direction as Y, and its thickness direction as Z. It should be understood that the above definitions of directions are for the convenience of describing this invention, and the directions defined in this invention can be understood based on the relative positions of the figures and the actual product. It is understood that the length, width, and thickness directions of the negative electrode current collector 11 and the negative electrode silicon-based active material are the same as those of the negative electrode sheet 10. Figures 1 and 2 show the negative electrode sheet 10 along its length direction X in one embodiment of this invention, and Figure 3 shows the negative electrode sheet 10 along its thickness direction Z in one embodiment of this invention.

[0056] As shown in Figures 1-3, the negative electrode sheet 10 provided by the present invention includes a negative electrode current collector 11, a negative electrode tab 12 disposed on the negative electrode current collector 11, and a negative electrode silicon-based active material. The negative electrode current collector 11 includes a first coating surface 111 and a second coating surface 112 disposed along its own thickness direction Z. The negative electrode silicon-based active material provided by the present invention is disposed on both the first coating surface 111 and the second coating surface 112 of the negative electrode current collector 11.

[0057] As shown in Figures 1 and 3, a first coating surface 111 is formed on the upper surface of the negative electrode current collector 11 by a silicon-based negative electrode active material. A first coating area 111A and a second coating area 111B are provided on the first coating surface 111, with the same length. The thickness of the first coating area 111A is the thickness of the active material formed after the silicon-based negative electrode active material is coated and rolled on the upper surface of the negative electrode current collector 11. A first blank area 111C is also provided between the first coating area 111A and the second coating area 111B. The first blank area 111C does not contain any silicon-based negative electrode active material and is used for welding the negative electrode tab 12. A first side edge 113 is also provided on the first coating surface 111. The first side edge 113 does not contain any silicon-based negative electrode active material. The first blank area 111C and the first side edge 113, which do not contain any silicon-based negative electrode active material, constitute the surface of the negative electrode current collector 11 itself.

[0058] As shown in Figures 2-3, a second coating surface 112 is formed on the lower surface of the negative electrode current collector 11 by the negative electrode silicon-based active material. A third coating region 112A and a fourth coating region 112B are provided on the second coating surface 112, and the third coating region 112A and the fourth coating region 112B have the same length. The thickness of the second coating surface 112 is the thickness of the active material formed after the negative electrode silicon-based active material is coated and rolled on the lower surface of the negative electrode current collector 11. A second blank area 112C is also provided between the third coating region 112A and the fourth coating region 112B. The second blank area 112C does not contain the negative electrode silicon-based active material and is the back side of the first blank area 111C where the negative electrode tab 12 is soldered. A second side 114 is provided on the second coating surface 112. There is no negative electrode silicon-based active material in the second side 114. The second blank area 112C and the second side 114 without negative electrode silicon-based active material are the surface of the negative electrode current collector 11 itself.

[0059] To better control the stability of the negative electrode silicon-based active material on the negative electrode current collector 11 during battery operation and to improve the conductivity of the negative electrode silicon-based active material, the thickness of the first coating surface 111 of the negative electrode sheet 10 in this invention is 6μm-10μm; the thickness of the second coating surface 112 is 6μm-10μm. The sum of the thicknesses of the first coating surface 111 and the second coating surface 112 on the negative electrode sheet 10 is controlled between 12μm and 20μm, so that the thickness of the negative electrode sheet 10 is much smaller than that of conventional negative electrode sheets. The thickness of the negative electrode silicon-based active material disposed on the first coating surface 111 and the second coating surface 112 of the negative electrode current collector 11 in the negative electrode sheet 10 provided by this invention can be the same or different; that is, the thickness of the first coating surface 111 and the second coating surface 112 can be the same, or the thickness of the first coating surface 111 can be greater than the thickness of the second coating surface 112, or the thickness of the first coating surface 111 can be smaller than the thickness of the second coating surface 112. The thickness of the negative electrode silicon-based active material on the first coating surface 111 or the thickness of the negative electrode silicon-based active material on the second coating surface 112 can be adjusted individually as needed. Adjusting the thickness of the negative electrode silicon-based active material on both surfaces individually requires controlling the sum of the thicknesses of the two coating surfaces between 12μm and 20μm. By controlling the sum of the thicknesses of the first coating surface 111 and the second coating surface 112 of the negative electrode sheet 10 between 12μm and 20μm, this invention can effectively shorten the transport distance of electrons and lithium ions within the electrode sheet. This helps to reduce the internal resistance of the battery and improve its rate performance.

[0060] The negative electrode 10 provided by this invention uses a silicon-based active material comprising pure silicon particles. The mass percentage of pure silicon in the silicon-based active material is 65-100%, for example, 65%, 75%, 85%, 95%, 100%, or any value between any two of the above ranges. However, it is worth noting that 100% pure silicon content is only discussed as a theoretical limit. In practical applications, since pure silicon is difficult to achieve a completely impurity-free state in its natural state, the so-called "100% pure silicon content" does not actually exist. Even after a highly refined process, silicon materials will still contain trace amounts of impurity elements such as iron, aluminum, and calcium. The silicon-based active material provided by this invention can be pure silicon, or pure silicon and graphite, or pure silicon and silicon-carbon materials, or silicon composite materials.

[0061] When the silicon-based active material for the negative electrode is selected from pure silicon and graphite, pure silicon and silicon-carbon materials, or silicon composite materials, the mass percentage of pure silicon in the silicon-based active material is controlled at 65-100%. This invention selects a negative electrode active material containing pure silicon particles, which have a very high theoretical specific capacity (up to 4200 mAh / g), far exceeding the theoretical specific capacity of traditional graphite negative electrodes (372 mAh / g). Therefore, using a negative electrode active material containing pure silicon particles can significantly improve the energy density of the battery, enabling the battery to store more energy with the same weight or volume. Furthermore, compared to other high-performance negative electrode materials, pure silicon particles have a relatively low cost, giving them a potential cost advantage in large-scale commercial applications.

[0062] In one embodiment, the specific capacity of the pure silicon particles in the negative electrode active material provided by this invention is ≥3200mAh / g. As the main component for lithium storage in a battery, the negative electrode silicon-based active material enables the insertion and extraction of lithium ions during charging and discharging. The selection of the negative electrode silicon-based active material directly affects the overall lithium storage capacity of the lithium-ion battery, i.e., the capacity of a single cell. This invention selects high-specific-capacity pure silicon particles as a key component of the negative electrode active material to ensure the energy density of the negative electrode silicon-based active material.

[0063] In one embodiment, the average particle size of the pure silicon particles in the negative electrode active material provided by the present invention is 3.0-6.0 μm. For example, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 5.0 μm, 5.5 μm, 6.0 μm, preferably any value within any two of the above ranges. By optimizing the particle size of the pure silicon particles to be within the range of 3.0-6.0 μm, the present invention helps to shorten the diffusion path of lithium ions within the pure silicon particles, thereby improving the charge and discharge rate of the battery. Furthermore, the smaller particle size of the pure silicon particles provides more interparticle contact points, which helps to disperse the stress caused by volume changes and improve the stability of the battery.

[0064] In one embodiment, the bifacial areal density of the negative electrode 10 is 1.6-2.4 mg / cm³. 2 For example, the areal density of the two coated surfaces of the negative electrode 10 is 1.6 mg / cm³. 2 1.8 mg / cm 2 2.0 mg / cm 2 2.2 mg / cm 2 2.4 mg / cm 2 Or any value between any two of the above-mentioned numerical ranges. The areal density values ​​in this invention are rounded to one decimal place during design and recording; however, slight fluctuations in the areal density values ​​still need to be considered in actual production, and this fluctuation must be ensured to be within a controllable range. This application, by optimizing the bifacial areal density of the negative electrode sheet 10, can achieve control over the thickness of the negative electrode sheet 10, improve the utilization rate of the negative electrode material, and thus increase the battery capacity and energy density.

[0065] The double-sided areal density of the negative electrode sheet 10 mentioned in this invention refers to the mass of the negative electrode active material per unit area, wherein both the upper and lower surfaces of the negative electrode sheet 10 are coated with negative electrode active material. The method for measuring the unit areal density of the negative electrode sheet 10 is as follows: Step 1. Use a sampler to take a circular piece of foil of a predetermined area from the empty foil and weigh it to obtain the foil weight; Step 2. Use a sampler to take a circular electrode sheet of the same size from the double-sided coated electrode sheet and weigh it, subtract the foil weight from Step 1, and divide by the circular area to obtain the unit areal density; Steps 1-2 can be repeated to obtain the actual areal density at different positions of the negative electrode sheet 10 and then take the average value.

[0066] When the areal density of both sides of the negative electrode 10 is greater than 2.4 mg / cm³ 2This means that more negative electrode active material is loaded on the same area, which theoretically may increase the battery capacity. However, excessively high areal density increases the thickness of the negative electrode sheet 10, leading to increased internal resistance and affecting the battery's charge and discharge efficiency, thus limiting the increase in battery capacity to some extent. When the bifacial areal density of the negative electrode sheet 10 is less than 1.6 mg / cm³, the battery capacity improvement is limited. 2 When the amount of active material in the double-sided coating is reduced, the amount of active material in the coating means that the number of lithium ions that can be stored and released during charging and discharging is reduced, and the energy that can be stored per unit volume is also reduced, so the battery capacity will also decrease.

[0067] In one embodiment, the compaction density of the negative electrode 10 is 1.10-1.30 g / cm³. 3 For example, the compaction density of the negative electrode 10 is 1.10 g / cm³. 3 1.15g / cm 3 1.20g / cm 3 1.25g / cm 3 1.30g / cm 3 Or any value between any two of the above-mentioned numerical ranges. The compaction density values ​​in this invention are rounded to two decimal places during design and recording; however, slight fluctuations in the areal density values ​​must still be considered in actual production, and these fluctuations must be ensured to be within a controllable range. By controlling the compaction density of the negative electrode sheet 10, the porosity and void distribution of the negative electrode sheet 10 can be controlled, thereby adjusting the ion conduction capability of the battery during charging and discharging, and thus changing the rate performance of the battery. When the compaction density of the negative electrode sheet 10 is greater than 1.30 g / cm³... 3 Excessive compaction density can easily lead to excessive stress within the negative electrode 10, causing particle breakage within the silicon-based negative electrode material and affecting electrode performance; when the compaction density of the negative electrode 10 is less than 1.10 g / cm³... 3 If the compaction density is too low, it will lead to insufficient filling of active material in the negative electrode 10, thereby reducing the battery capacity. On the other hand, it may also lead to an increase in the voids inside the negative electrode 10, thereby increasing the internal resistance of the battery and affecting the rate performance of the battery.

[0068] The inventors of this application utilize the principle of interaction between the compaction density and the areal density of the negative electrode sheet 10. By controlling the compaction density and the areal density of both sides of the negative electrode sheet 10, the thickness of the negative electrode silicon-based active material on the negative electrode current collector 11 can be controlled. Furthermore, by optimizing the negative electrode copper foil current collector, the thickness of the current collector is controlled within the range of 6-8 μm, thereby controlling the overall thickness of the negative electrode sheet 10 between 18 μm and 28 μm. This precise control of the thickness of the negative electrode sheet 10 helps reduce the voids inside the battery, thereby reducing the battery's internal resistance and improving its charge / discharge efficiency and power output capability. Simultaneously, it can also optimize the battery's volumetric capacity, thereby increasing the battery's energy density.

[0069] In one embodiment, the first coating surface 111 and the second coating surface 112 of the negative electrode sheet 10 each include two negative electrode coating areas. The negative electrode tab 12 is disposed within a first blank area 111C between the two negative electrode coating areas of the first coating surface 111, and the negative electrode tab 12 may also be disposed within a second blank area 112C between the two negative electrode coating areas of the second coating surface 112. The first coating area 111A and the second coating area 111B of the first coating surface 111 of the negative electrode sheet 10 have the same length, and the third coating area 112A and the fourth coating area 112B of the second coating surface 112 of the negative electrode sheet 10 also have the same length.

[0070] As shown in Figures 1-3, the negative electrode sheet 10 provided by the present invention has a negative electrode tab 12 disposed in the middle of the first blank area 111C between the two negative electrode coating areas of the first coating surface 111. This arrangement allows electrons to flow simultaneously from the first coating area 111A and the second coating area 111B on both sides of the first blank area 111C to the negative electrode tab 12; or from the negative electrode tab 12 to the first coating area 111A and the second coating area 111B on both sides of the first blank area 111C. This shortens the electron path in the negative electrode sheet 10, thereby reducing the internal resistance of the negative electrode sheet 10 and improving the rate performance of the battery.

[0071] In one embodiment of the present invention, the negative electrode tab 12 includes a first conductive sheet 121 and a first insulating sheet 122. The first conductive sheet 121 is welded to the first blank area 111C of the first coating surface 111 by a first ultrasonic solder joint 121A. The first insulating sheet 122 is attached to the first conductive sheet 121 and the negative current collector 11 to protect the first conductive sheet 121 within the first insulating sheet 122 and prevent short circuits between the positive and negative electrodes caused by burrs generated by the first conductive sheet 121. Similarly, a second insulating sheet 123 is attached to the second blank area 112C of the second coating surface 112, i.e., the side opposite to the negative electrode tab 12, to prevent short circuits between the positive and negative electrodes caused by burrs generated by the first conductive sheet 121. In this embodiment, the first conductive sheet 121 in the negative electrode tab 10 is a copper-nickel tab with a width of 2-4 mm, and the first insulating sheet 122 and the second insulating sheet 123 are made of polyimide tape.

[0072] In one embodiment, the distance between the two coating areas of the first coating surface 111 of the negative electrode 10 is 2-8 times the width of the negative electrode tab 12. In this invention, the width of the negative electrode tab 12 is preferably 2-4 mm, and the distance between the first coating area 111A and the second coating area 111B is preferably 4-32 mm. By reasonably setting the distance between the two coating areas, the space between the negative electrode tab 12 and the two coating areas can be fully utilized, which helps to increase the amount of active material within a limited battery volume, thereby increasing the battery's energy density. When the distance between the first coating area 111A and the second coating area 111B is too narrow, it may lead to current concentration, increasing local resistance and heat generation, and increasing the risk of thermal runaway. When the distance between the first coating area 111A and the second coating area 111B is too wide, it means that the area on the negative electrode 10 without active material coating is larger, which will lead to a reduction in the amount of negative electrode active material, thereby reducing the battery's energy density.

[0073] In one embodiment, the welding area between the negative electrode tab 12 and the negative electrode sheet 10 is greater than 8 mm². 2 Ensure the welding area is greater than 8mm. 2 The purpose is twofold: firstly, to ensure a more stable and reliable connection between the negative electrode tab 12 and the negative electrode sheet 10, which helps reduce the risk of local overheating and thermal runaway caused by poor connection; secondly, to reduce the contact resistance between the negative electrode tab 12 and the negative electrode sheet 10 by increasing the area of ​​the welding area, which helps improve the charging and discharging efficiency and rate performance of the battery.

[0074] Secondly, the present invention also provides a method for preparing a negative electrode sheet 10, comprising the following steps:

[0075] A: Pure silicon particle material, conductive agent and binder are evenly dispersed in solvent to obtain negative electrode coating slurry. The solid content of the negative electrode coating slurry is 10-15wt%, and the viscosity of the negative electrode coating slurry is 4000-15000mPa·s.

[0076] B: The negative electrode coating slurry is coated on the surface of the current collector, and after drying and rolling, the negative electrode sheet 10 is obtained.

[0077] In this invention, the conductive agent includes a one-dimensional conductive agent, a two-dimensional conductive agent, and super carbon black (SP). The one-dimensional conductive agent preferably includes one or more of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), carbon nanofibers (CNFs), silver nanofibers, and copper nanofibers. The two-dimensional conductive agent includes graphene (RGO) and / or graphyne (GDY). Since super carbon black and the one-dimensional conductive agent have large specific surface areas, their addition can increase surface energy and improve the viscosity of the slurry, but it is not conducive to the dispersion of the slurry. Therefore, a two-dimensional conductive agent, such as graphene, is also needed. The addition of graphene can have a lubricating effect, making the slurry easier to disperse. This invention preferably uses single-walled carbon nanotubes, super carbon black, and graphene as the negative electrode conductive agent, wherein the conductive agent can be in slurry form. The mass ratio of pure silicon particles to the conductive agent is preferably (80-99):(0.5-20), more preferably (85-95):(5-15).

[0078] In this invention, the binder includes one or more of polyacrylic acid (PAA), polyacrylamide (PAM), sodium alginate (SA), sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR); the addition of polyacrylic acid (PAA), polyacrylamide (PAM), sodium alginate (SA), sodium carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR) can all increase the viscosity of the slurry. This invention preferably uses polyacrylic acid (PAA) and polyacrylamide (PAM) as the negative electrode binder, wherein the binder can be in slurry form. The mass ratio of pure silicon particles to conductive agent is preferably (80-99):(0.5-20), more preferably (80-95):(5-15).

[0079] In this invention, the total mass of pure silicon particles, conductive agent, and binder is 100%, wherein the proportion of pure silicon particles is 80-99%, preferably 85-95%, such as 85%, 90%, 95%, preferably within the range of any of the above values ​​as the upper or lower limit. The proportion of conductive agent is 0.5-20%, more preferably 0.5-10%, such as 0.5%, 5%, 10%, preferably within the range of any of the above values ​​as the upper or lower limit. The proportion of binder is 0-20%, more preferably 0.5-10%, such as 0.5%, 5%, 10%, preferably within the range of any of the above values ​​as the upper or lower limit. In this invention, deionized water is preferred as the solvent.

[0080] In this invention, the solid content of the negative electrode coating slurry is controlled at 10-15 wt%, and the viscosity is controlled at 4000-15000 mPa·s. The solid content directly affects the uniformity of the coating. Excessive solid content may lead to poor slurry flowability, making it difficult to form a uniform coating on the electrode, thus affecting battery performance. Insufficient solid content, on the one hand, makes coating difficult, and on the other hand, may cause the active materials inside the electrode to easily peel off or be lost during charge-discharge cycles, damaging the stability of the electrode structure and thus shortening the battery's lifespan. In this invention, when the solid content is within the range of 10-15 wt% and the viscosity is controlled within the range of 4000-15000 mPa·s, the slurry has moderate flowability, making it easy to level and dry, which is beneficial for improving coating efficiency and ensuring battery performance.

[0081] In this invention, pure silicon particles, binder, and conductive agent are mixed and stirred evenly in deionized water at a mass ratio of (80-95):(5-15):(5-15) to prepare a negative electrode coating slurry. To ensure uniform dispersion, the mixing time is preferably more than 3 hours. The one-dimensional conductive agent is preferably added last. This is because one-dimensional conductive agents, such as carbon nanotubes (CNTs), have a unique fibrous structure and are prone to agglomeration under van der Waals forces. To avoid agglomeration, they are usually added at the final stage of the mixing process. This ensures that the conductive agent can be rapidly and uniformly dispersed in the electrode material after addition, thereby improving its conductivity.

[0082] In this invention, the current collector can be a copper foil, a carbon-coated copper foil, or a three-dimensional porous copper foil, and the thickness of the current collector is controlled between 6μm and 8μm, preferably 6μm or 8μm.

[0083] The present invention does not impose any special limitation on the coating method; any coating method commonly used by those skilled in the art can be used.

[0084] In this invention, the drying temperature is preferably 70-120℃, more preferably 80-100℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, and preferably a range of values ​​with any of the above values ​​as the upper or lower limit.

[0085] This invention increases the total specific surface area of ​​all particles in the slurry by using various conductive agents with high specific surface area, combined with a binder system with good thickening effect, and at the same time, optimizes the mixing sequence to ensure the fluidity of the slurry, so that it can be mixed evenly in a short time.

[0086] Thirdly, the present invention also provides a cylindrical battery 100, as shown in Figure 7, which is a structural schematic diagram of the cylindrical battery 100 provided by the present invention. The cylindrical battery 100 provided by the present invention includes a cylindrical core formed by an aluminum-plastic shell 40, a positive electrode 20, a negative electrode 10, and a separator 30, and an electrolyte disposed within the shell. The aluminum-plastic shell 40 contains the separator 30, the negative electrode 10, the separator 30, and the positive electrode 20 wound together to form a cylindrical core. The electrolyte is disposed within the aluminum-plastic shell 40, with one end outside the shell being the positive terminal and the other end being the negative terminal.

[0087] In one embodiment, the cylindrical battery 100 provided by the present invention further includes a positive electrode 20. Figures 4-6 show schematic diagrams of the structure of the positive electrode 20 provided in the cylindrical battery 100 of the present invention. The positive electrode 20 includes a positive current collector 21, a positive electrode tab 22 disposed on the positive current collector 21, and a positive active material. The positive active material can be selected from lithium manganese oxide or lithium cobalt oxide, both of which can be combined with the negative electrode 10 of the present invention to obtain a high-performance cylindrical battery 100. Because the electronic cigarette industry has certain requirements for high voltage and high rate of operation of batteries, lithium iron phosphate and ternary materials, due to their lower voltage, have limited their application to some extent.

[0088] The positive electrode active material in the positive electrode sheet 20 provided by this invention is lithium cobalt oxide, with a proportion of 80-100 wt% in the positive electrode active material. Lithium cobalt oxide has a high initial discharge specific capacity. When the proportion of lithium cobalt oxide in the positive electrode active material of this invention reaches 80-100 wt%, it indicates that lithium cobalt oxide is the main component of the positive electrode material. This is because it is difficult to obtain 100% pure lithium cobalt oxide in actual production and application. This invention uses high-content lithium cobalt oxide as the positive electrode active material of the e-cigarette battery, which can store more electrical energy and provide a longer battery life. In addition, the voltage platform of lithium cobalt oxide is generally higher than that of many other common lithium-ion battery positive electrode materials. The charging voltage of high-voltage lithium cobalt oxide materials can even reach 4.3V or even 4.4V. Using lithium cobalt oxide as the positive electrode active material to prepare e-cigarette lithium batteries helps to provide a more stable voltage output during operation, ensuring the normal operation of the e-cigarette.

[0089] In one embodiment, the average particle size of the positive electrode active material lithium cobalt oxide provided by the present invention is 4.5-6.0 μm. For example, 4.5 μm, 5.0 μm, 5.5 μm, 6.0 μm, preferably any value within any two of the above ranges. By employing small-diameter lithium cobalt oxide particles, the present invention facilitates the insertion and extraction of Li+ ions, shortens the transport paths of ions and electrons within the material, reduces internal resistance, and further improves battery performance.

[0090] In the positive electrode sheet 20 provided by the present invention, as shown in FIG. 6, the positive current collector 21 includes a third coating surface 211 and a fourth coating surface 212 disposed along its own thickness direction Z. The third coating surface 211 includes a fifth coating region 211A and a sixth coating region 211B, and the fourth coating surface 212 includes a seventh coating region 212A and an eighth coating region 212B. The positive electrode active material is disposed on the fifth coating region 211A and the sixth coating region 211B of the third coating surface 211, and on the seventh coating region 212A and the eighth coating region 212B of the fourth coating surface 212, that is, the positive electrode active material is respectively located on two opposite surfaces of the positive current collector 21. The fifth coating region 211A and the sixth coating region 211B of the third coating surface 211 of the positive electrode sheet 20 have the same length. The seventh coating region 212A and the eighth coating region 212B of the fourth coating surface 212 of the positive electrode sheet 20 also have the same length. A third side 213 is provided on the third coating surface 211. The third side 213 does not contain any negative electrode silicon-based active material. The third blank area 211C, which does not contain any positive electrode active material, and the third side 213 constitute the surface of the positive electrode current collector 21 itself. A fourth side 214 is provided on the fourth coating surface 212. The fourth side 214 does not contain any negative electrode silicon-based active material. The positive electrode tab 22 is disposed in the third blank area 211C between the two positive electrode coating areas of the third coating surface 211, or in the fourth blank area 212C between the two positive electrode coating areas of the fourth coating surface 212.

[0091] As shown in Figures 4-6, the positive electrode 20 provided by this invention has a positive electrode tab 22 disposed in the middle of the third blank area 211C between the two positive electrode coating areas of the third coating surface 211. This arrangement allows electrons to flow simultaneously from the fifth coating area 211A and the sixth coating area 211B on both sides of the third blank area 211C to the positive electrode tab 22; or from the positive electrode tab 22 to the fifth coating area 211A and the sixth coating area 211B on both sides of the third blank area 211C. This shortens the electron path in the positive electrode 20, thereby reducing the internal resistance of the positive electrode 20. This helps to improve the charging and discharging efficiency of the battery and improve the rate performance of the battery.

[0092] In one embodiment of the present invention, the positive electrode tab 22 includes a second conductive sheet 221 and a third insulating sheet 222. The second conductive sheet 221 is welded to the third blank area 211C of the third coating surface 211 by a second ultrasonic solder joint 221A. The third insulating sheet 222 is attached to the second conductive sheet 221 and the positive current collector 21 to protect the second conductive sheet 221 within the third insulating sheet 222, preventing a short circuit between the positive and negative electrodes caused by burrs generated by the second conductive sheet 221. Similarly, a fourth insulating sheet 223 is attached to the fourth blank area 212C of the fourth coating surface 212, i.e., the side opposite to the positive electrode tab 22, to prevent a short circuit between the positive and negative electrodes caused by burrs generated by the second conductive sheet 221.

[0093] The width of the positive electrode tab 22 of the positive electrode 20 provided by this invention is the same as the width of the negative electrode tab 12 of the negative electrode 10. That is, the width of the second conductive sheet 221 in the positive electrode 20 is the same as the width of the first conductive sheet 121 in the negative electrode 10. In this embodiment, the second conductive sheet 221 in the positive electrode 20 is made of aluminum tab with a width of 2-4 mm, and the third insulating sheet 222 and the fourth insulating sheet 223 are made of polyimide tape.

[0094] In one embodiment of the present invention, the length of the negative electrode 10 is greater than the length of the positive electrode 20, and the negative electrode 10 covers the positive electrode 20. Specifically, the length of the third side 213 or the fourth side 214 of the positive electrode 20 is greater than the length of the first side 113 or the second side 114 of the negative electrode 10, and the length of the third blank area 211C or the fourth blank area 212C of the positive electrode 20 is greater than the length of the first blank area 111C or the second blank area 112C of the negative electrode 10, so that the negative electrode active material can completely cover the positive electrode active material, thereby avoiding lithium deposition on the negative electrode 10 and / or the positive electrode 20. During the cylindrical core winding process of the present invention, the separator 30 is wound first, and after the negative electrode 10 is wound 1.5 turns, the positive electrode 20 is wound next, so that the negative electrode 10 covers the positive electrode 20, and the outer separator 30 covers the negative electrode 10.

[0095] In one embodiment, the length of the positive electrode 20 in the cylindrical battery 100 provided by the present invention is 745-750 mm; for example, the length of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 745 mm, 746 mm, 747 mm, 748 mm, 749 mm, 750 mm, or any value between any two of the above ranges. The width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 20-25 mm; for example, the width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, or any value between any two of the above ranges. The negative electrode 10 of the cylindrical battery 100 provided by the present invention has a length of 800-805 mm; for example, the length of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 800 mm, 801 mm, 802 mm, 803 mm, 804 mm, 805 mm, or any value between any two of the above ranges. The width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 20-25 mm; for example, the width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, or any value between any two of the above ranges. The capacity ratio (N / P ratio) of the positive electrode 20 and the negative electrode 10 in the cylindrical battery 100 provided by the present invention is 1.2-1.4. The cylindrical battery 100 provided by this invention has negative electrode 10 and positive electrode 20 whose lengths meet the casing dimensions of a 13300 model battery, wherein the casing dimensions of the cylindrical battery 100 corresponding to the 13300 model are a diameter of 13mm and a height of 300mm. The cylindrical battery 100 provided by this invention has a capacity of 580-700mAh at a discharge rate of 0.2C.

[0096] In one embodiment, the length of the positive electrode 20 in the cylindrical battery 100 provided by the present invention is 745-750 mm; for example, the length of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 745 mm, 746 mm, 747 mm, 748 mm, 749 mm, 750 mm, or any value between any two of the above ranges. The width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 25-30 mm; for example, the width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, or any value between any two of the above ranges. The negative electrode 10 of the cylindrical battery 100 provided by the present invention has a length of 800-805 mm; for example, the length of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 800 mm, 801 mm, 802 mm, 803 mm, 804 mm, 805 mm, or any value between any two of the above ranges. The width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 25-30 mm; for example, the width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, or any value between any two of the above ranges. The capacity ratio (N / P ratio) of the positive electrode 20 and the negative electrode 10 in the cylindrical battery 100 provided by the present invention is 1.2-1.4. The cylindrical battery 100 provided by this invention has negative electrode 10 and positive electrode 20 whose lengths meet the casing dimensions of a 13350 model battery, wherein the casing dimensions of the cylindrical battery 100 corresponding to the 13350 model are a diameter of 13mm and a height of 350mm. The cylindrical battery 100 provided by this invention has a capacity of 710-810mAh at a discharge rate of 0.2C.

[0097] In one embodiment, the length of the positive electrode 20 in the cylindrical battery 100 provided by the present invention is 745-750 mm; for example, the length of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 745 mm, 746 mm, 747 mm, 748 mm, 749 mm, 750 mm, or any value between any two of the above ranges. The width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 30-35 mm; for example, the width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, or any value between any two of the above ranges. The negative electrode 10 of the cylindrical battery 100 provided by the present invention has a length of 800-805 mm; for example, the length of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 800 mm, 801 mm, 802 mm, 803 mm, 804 mm, 805 mm, or any value between any two of the above ranges. The width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 30-35 mm; for example, the width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, or any value between any two of the above ranges. The capacity ratio (N / P ratio) of the positive electrode 20 and the negative electrode 10 in the cylindrical battery 100 provided by the present invention is 1.2-1.4. The cylindrical battery 100 provided by this invention has negative electrode 10 and positive electrode 20 whose lengths meet the casing dimensions of a 13400 model battery, wherein the casing dimensions of the cylindrical battery 100 corresponding to the 13400 model are a diameter of 13mm and a height of 400mm. The cylindrical battery 100 provided by this invention has a capacity of 820-920mAh at a discharge rate of 0.2C.

[0098] In one embodiment, the length of the positive electrode 20 in the cylindrical battery 100 provided by the present invention is 1300-1320 mm; for example, the length of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 1300 mm, 1305 mm, 1310 mm, 1315 mm, 1320 mm, or any value between any two of the above ranges. The width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 25-35 mm; for example, the width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 25 mm, 27 mm, 29 mm, 31 mm, 33 mm, 35 mm, or any value between any two of the above ranges. The negative electrode 10 of the cylindrical battery 100 provided by the present invention has a length of 1360-1380 mm; for example, the length of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 1360 mm, 1365 mm, 1370 mm, 1375 mm, 1380 mm, or any value between any two of the above ranges. The width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 25-35 mm; for example, the width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 25 mm, 27 mm, 29 mm, 31 mm, 33 mm, 35 mm, or any value between any two of the above ranges. The capacity ratio (N / P ratio) of the positive electrode 20 and the negative electrode 10 in the cylindrical battery 100 provided by the present invention is 1.2-1.4. The cylindrical battery 100 provided by this invention has negative electrode 10 and positive electrode 20 whose lengths meet the casing dimensions of the 18350 model battery, wherein the casing dimensions of the cylindrical battery 100 corresponding to the 18350 model are 18mm in diameter and 350mm in height. The cylindrical battery 100 provided by this invention has a capacity of 1000-1600mAh at a discharge rate of 0.2C.

[0099] In one embodiment, the length of the positive electrode 20 in the cylindrical battery 100 provided by the present invention is 1300-1320 mm; for example, the length of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 1300 mm, 1305 mm, 1310 mm, 1315 mm, 1320 mm, or any value between any two of the above ranges. The width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 40-45 mm; for example, the width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 40 mm, 41 mm, 42 mm, 43 mm, 44 mm, 45 mm, or any value between any two of the above ranges. The negative electrode 10 of the cylindrical battery 100 provided by the present invention has a length of 1360-1380 mm; for example, the length of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 1360 mm, 1365 mm, 1370 mm, 1375 mm, 1380 mm, or any value between any two of the above ranges. The width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 40-45 mm; for example, the width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 40 mm, 41 mm, 42 mm, 43 mm, 44 mm, 45 mm, or any value between any two of the above ranges. The capacity ratio (N / P ratio) of the positive electrode 20 and the negative electrode 10 in the cylindrical battery 100 provided by the present invention is 1.2-1.4. The cylindrical battery 100 provided by this invention has negative electrode 10 and positive electrode 20 whose lengths meet the casing dimensions of an 18500 model battery, wherein the casing dimensions of the cylindrical battery 100 corresponding to the 18500 model are a diameter of 18mm and a height of 500mm. The cylindrical battery 100 provided by this invention has a capacity of 2100-2400mAh at a discharge rate of 0.2C.

[0100] In one embodiment, the length of the positive electrode 20 in the cylindrical battery 100 provided by the present invention is 1300-1320 mm; for example, the length of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 1300 mm, 1305 mm, 1310 mm, 1315 mm, 1320 mm, or any value between any two of the above ranges. The width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 50-55 mm; for example, the width of the positive electrode 20 of the cylindrical battery 100 provided by the present invention is 50 mm, 51 mm, 52 mm, 53 mm, 54 mm, 55 mm, or any value between any two of the above ranges. The negative electrode 10 of the cylindrical battery 100 provided by the present invention has a length of 1360-1380 mm; for example, the length of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 1360 mm, 1365 mm, 1370 mm, 1375 mm, 1380 mm, or any value between any two of the above ranges. The width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 50-55 mm; for example, the width of the negative electrode 10 of the cylindrical battery 100 provided by the present invention is 50 mm, 51 mm, 52 mm, 53 mm, 54 mm, 55 mm, or any value between any two of the above ranges. The capacity ratio (N / P ratio) of the positive electrode 20 and the negative electrode 10 in the cylindrical battery 100 provided by the present invention is 1.2-1.4. The cylindrical battery 100 provided by this invention has negative electrode 10 and positive electrode 20 whose lengths meet the casing dimensions of an 18600 model battery, wherein the casing dimensions of the cylindrical battery 100 corresponding to the 18600 model are a diameter of 18mm and a height of 600mm. The cylindrical battery 100 provided by this invention has a capacity of 2500-2900mAh at a discharge rate of 0.2C.

[0101] Furthermore, the present invention also provides an electronic cigarette, including the aforementioned cylindrical battery 100. The cylindrical battery 100 has a high energy density, which can extend the usage time of the electronic cigarette and reduce the need for frequent charging. The cylindrical battery 100 of the present invention has a high voltage platform, which helps ensure consistent vapor production and flavor during use, improves the user experience, and contributes to the superior performance of the electronic cigarette product, thereby enhancing its market competitiveness.

[0102] The present invention will be further described in detail below with reference to embodiments and comparative examples:

[0103] The following describes embodiments of this application. The facts described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Specific techniques or conditions are not specified in the embodiments; they are performed according to techniques or conditions described in the literature in the art or according to product instructions. All reagents used, or those whose manufacturers are not specified, are conventional products that can be obtained commercially.

[0104] 100 cylindrical batteries

[0105] Example 1:

[0106] (1) Preparation of negative electrode 10:

[0107] Micron-sized pure silicon particles were used as the silicon-based active material for the negative electrode. These particles were mixed with binder PAA, binder PAM, conductive agent CNT, conductive agent SP, and conductive agent RGO in deionized water at a mass ratio of 91:0.8:1.7:1:2:2 to prepare a negative electrode coating slurry. The slurry was prepared at a concentration of 1.9 mg / cm³. 2 The areal density is coated on both sides of a copper foil with a thickness of 6μm and a length of 803mm. The coated length is 784mm, with a 7mm blank length at one end. A 12mm blank area is left in the middle of the front length direction of the negative electrode 10. After cold pressing, it is cut into an electrode with a width of 24mm, a thickness of 21μm, and a length of 803mm. After welding the tab to the 12mm blank area in the middle of the front length direction of the negative electrode 10, a negative electrode 10 with a negative silicon-based active material attached to the surface is obtained. The specific capacity of the negative silicon-based active material in the negative electrode 10 is 3600mAh / g.

[0108] (2) Preparation of positive electrode 20:

[0109] Lithium cobalt oxide (LCO) was used as the positive electrode active material. It was mixed with binder polytetrafluoroethylene (PVDF), conductive agent SP, and conductive agent MWCNT in N-methylpyrrolidone (NMP) at a mass ratio of 96:1.14:1.5:1.09 to form a positive electrode slurry. The positive electrode slurry was coated on both sides of an aluminum foil with a thickness of 12μm and a length of 748mm at a surface density of 28mg / cm2. One end was left blank for 10mm. A blank area of ​​48mm was left in the middle of the front length direction of the positive electrode sheet 20. The positive electrode sheet 20 was cold-pressed and cut into a positive electrode sheet 20 with a width of 23±1mm, a thickness of 81μm, and a length of 748mm. Positive electrode tabs 22 were welded in the blank area in the middle of the front length direction of the positive electrode sheet 20 to obtain a positive electrode sheet 20 with positive electrode active material attached to its surface.

[0110] (3) Preparation of diaphragm 30

[0111] The selected diaphragm is 30 with a thickness of 16μm, made of a ceramic / polyethylene (PE) / ceramic three-layer separator, with a length of 1850mm and a width of 27mm.

[0112] (4) Preparation of electrolyte

[0113] In an argon-filled glove box (moisture <10 ppm, oxygen <10 ppm), diethyl carbonate (DEC), propylene carbonate (PC), ethylene carbonate (EC), and fluoroethylene carbonate (FEC) were mixed in a mass ratio of DEC:PC:EC:FEC = 45:21:11:3 to obtain an organic solvent. Lithium salt LiPF6 was then dissolved in the mixed organic solvent to prepare a solution with a lithium salt concentration of 1.0 mol / L. Vinyl sulfate (DTD), adiponitrile (ADN), and 1,3-propenesulfonate lactone (PST) were then added and mixed thoroughly to obtain the electrolyte.

[0114] (5) Assembly of cylindrical battery 100

[0115] (a): Place the prepared negative electrode 10 and positive electrode 20 into a vacuum oven and bake to remove moisture;

[0116] (b): The baked negative electrode 10, positive electrode 20, and separator 30 are stacked in the order of "separator 30 / negative electrode 10 / separator 30 / positive electrode 20" and then wound into a cylindrical core. When winding, first wind the side of the negative electrode 10 that has no side edge, while ensuring that the coating surface of the negative electrode 10 completely covers the coating surface of the positive electrode 20.

[0117] (c): Punch the aluminum-plastic film according to the ratio of the diameter of the cylindrical core to the inner diameter of the aluminum-plastic film pit depth of 0.98, and fit the cylindrical core into the aluminum-plastic shell 40 pit.

[0118] (d): Hot press the aluminum-plastic shell 40 on both sides of the positive and negative electrode tabs at 180-290℃ and 0.4-0.6MPa for 3-6s to make the electrode tab sealing strength >30N and the aluminum-plastic shell 40 sealing strength >100N;

[0119] (e): Bake the semi-finished battery cell, inject 1.67g of electrolyte according to the electrolyte injection process, seal and impregnate, then charge to form:

[0120] (f): After formation, the cell edges are trimmed and then resealed with a vacuum of -90 kPa, a sealing temperature of 200-220°C, and a sealing pressure of 0.4-0.5 MPa to achieve a sealing strength >100 N;

[0121] (g): After the cells are sealed twice, the edges are folded, the tabs are folded, and the adhesive is applied according to the packaging process to obtain the finished 13300 model cells.

[0122] Examples 2-5:

[0123] Examples 2-5 illustrate other cylindrical batteries 100 of the present invention, including most of the operations in Example 1, except that the negative electrode active materials of the cylindrical batteries 100 in Examples 2-4 are different. When silicon-carbon and graphite materials are used as silicon-based negative electrode active materials, the different contents of silicon-carbon or graphite in the silicon-based negative electrode active materials result in different mass percentage contents of silicon in the silicon-based negative electrode active materials. The specific parameters are based on the data shown in Table 1 for each example.

[0124] Comparative Examples 1-3:

[0125] Comparative Examples 1-3 are used to compare and illustrate the cylindrical battery 100 of model 13300, including most of the operations in Example 1. The difference is that the materials selected in the negative electrode silicon-based active material in Comparative Examples 1-3 are different, resulting in different mass percentage contents of silicon element in the negative electrode silicon-based active material. The specific parameters are based on the data shown in Table 1 for each example.

[0126] Examples 6-10:

[0127] Examples 6-10 illustrate the cylindrical battery 100 of model 13400 of the present invention, which includes most of the operations in Example 1, except that the average particle size of the negative electrode active material is different in Examples 6-10. The specific parameters are based on the data shown in Table 1 for each example.

[0128] Examples 11-16:

[0129] Examples 11-16 are used to illustrate the cylindrical battery 100 of model 13350 of the present invention, which includes most of the operations in Example 1, except that the coating density of the negative electrode sheet 10 is different in Examples 11-16, resulting in different layer thicknesses of the negative electrode sheet 10. The specific parameters are based on the data shown in Table 1 for each example.

[0130] Examples 17-23:

[0131] Examples 17-23 are used to illustrate the cylindrical battery 100 of model 18600 of the present invention, which includes most of the operations in Example 1, except that the compaction density of the silicon-based active material of the negative electrode is different in Examples 17-23, resulting in different thicknesses of the 10 layers of negative electrode sheet. The specific parameters are based on the data shown in Table 1 for each example.

[0132] Examples 24-25:

[0133] Examples 24-25 illustrate the cylindrical battery 100 of model 18350 of the present invention, which includes most of the operations in Example 1, except that the positive electrode active material is different in Examples 24-25. The specific parameters are based on the data shown in Table 1 for each example.

[0134] Examples 26-30:

[0135] Examples 26-30 illustrate the cylindrical battery 100 of model 18500 of the present invention, which includes most of the operations in Example 1, except that the average particle size of the positive electrode active material is different in Examples 26-30. The specific parameters are based on the data shown in Table 1 for each example.

[0136] Table 1. Parameter table for Examples 1-30 and Comparative Examples 1-3

[0137] II. Performance testing of the cylindrical battery 100 obtained by the above preparation method.

[0138] (1) 0.2C discharge test method and battery capacity test

[0139] At an ambient temperature of 25℃, the battery was charged to 4.35V at a rate of 0.2C, then charged at a constant voltage until fully charged. After standing for 30 minutes, the battery was discharged to 2.5V at a rate of 0.2C. The discharge temperature rise and capacity utilization were recorded, and the discharge capacity was recorded as the nominal capacity of the cell.

[0140] (2) 3A discharge test method

[0141] At an ambient temperature of 25°C, the battery was charged to 4.35V at a rate of 0.2C, then charged at a constant voltage until fully charged. After resting for 30 minutes, it was discharged to 2.5V at a current of 3A. The discharge temperature rise and capacity utilization were recorded.

[0142] (3) 6A discharge test method

[0143] At an ambient temperature of 25°C, the battery was charged at a rate of 0.2C to 4.35V, then charged at a constant voltage until fully charged. After resting for 30 minutes, it was discharged at a current of 6A to 2.5V. The discharge temperature rise and capacity utilization were recorded.

[0144] (4) 8A discharge test method

[0145] At an ambient temperature of 25°C, the battery was charged at a rate of 0.2C to 4.35V, then charged at a constant voltage until fully charged. After standing for 30 minutes, it was discharged at a current of 8A to 2.5V. The discharge temperature rise and capacity utilization were recorded.

[0146] III. Analysis of Test Results for Each Embodiment and Comparative Example

[0147] Cylindrical batteries 100 of each embodiment and comparative example were prepared according to the above method, and various performance parameters were measured. The results are shown in Table 2 below.

[0148] Table 2 Test Results of Examples 1-30 and Comparative Examples 1-3

[0149] As shown in Example 1, for the 13300 model cylindrical battery 100, when the pure silicon content in the negative electrode silicon-based active material is 100%, the negative electrode active material consists of 3.5 μm pure silicon particles, and the areal density of the negative electrode sheet 10 is 1.9 mg / cm³. 2 The compacted density is 1.27 g / cm³. 3 At this time, the active material coating thickness on the negative electrode 10 is 15μm, that is, the sum of the thicknesses of the first coating surface 111 and the second coating surface 112 on the upper and lower surfaces of the negative electrode current collector 11 is controlled between 12μm and 20μm. Meanwhile, when the positive electrode active material is 5.0μm lithium cobalt oxide, under these parameters, the battery capacity is 650mAh, that is, at a discharge rate of 0.2C, the capacity of the 13300 model cylindrical battery 100 is 580-700mAh. The battery retains 98% of its capacity at a discharge rate of 3A, with a temperature rise of 16.9℃; at discharge rates of 6A and 8A, the capacity retention drops below 90%, and the temperature rise also increases significantly. This is mainly because as the discharge rate increases, the discharge current increases, generating more heat, while the time for the battery to dissipate heat from the external environment decreases, making it difficult for the heat generated inside the battery to dissipate quickly, thus leading to a rise in battery temperature. Simultaneously, the electrochemical reaction rate inside the battery accelerates accordingly, and the polarization effect inside the battery intensifies. This polarization effect hinders the migration of lithium ions, leading to a decrease in battery capacity. Comparing the data of different models of cylindrical batteries 100 in Table 2, all conform to the above-mentioned trend.

[0150] As can be seen from Examples 1-5 and Comparative Examples 1-3, the capacity of the 13300 cylindrical battery 100 gradually decreases as the proportion of pure silicon in the silicon-based negative electrode active material gradually decreases. This is mainly because pure silicon has an extremely high theoretical specific capacity, far exceeding that of traditional graphite. A decrease in the proportion of pure silicon in the silicon-based material leads to a decrease in the overall specific capacity of the negative electrode active material, thus causing a gradual decrease in battery capacity. Example 2 shows that when the pure silicon content is 95%, the battery capacity is 630mAh, slightly lower than in Example 1, but the capacity retention rate is relatively high at discharge rates of 6A and 8A. This is mainly because the negative electrode active material contains a small amount of graphite. Graphite has better rate performance than pure silicon particles, and the combination of the two active materials helps improve the rate performance and increase the capacity retention rate. Combined with Examples 2-5, it can be seen that using a small amount of graphite combined with pure silicon particles or silicon-carbon materials as the negative electrode active material results in a battery with high energy density and excellent rate performance. As can be seen from Comparative Examples 1-3, when the proportion of graphite or silicon-carbon materials in the negative electrode active material is relatively high, although the rate performance of the battery is improved to a certain extent, the specific capacity of graphite and silicon-carbon materials is lower than that of pure silicon, which will affect the energy density of the entire negative electrode material to a certain extent, and thus the battery capacity is lower than 600mAh.

[0151] As shown in Examples 6-10, the main adjustment for the 13400 model cylindrical battery 100 is the average particle size of the pure silicon particles used as the negative electrode active material. The table shows that when the average particle size of the pure silicon particles is between 3.0 and 6.5 μm, the capacity of the 13400 model cylindrical batteries 100 in Examples 6-8 is all above 820 mAh. However, as the average particle size increases, the battery capacity gradually decreases. This is because as the particle size of the negative electrode material increases, the effective surface area decreases, and the contact area between the electrode and the electrolyte also decreases, leading to a decrease in battery capacity. Under high-rate discharge conditions, the battery capacity retention rate gradually decreases as the average particle size of the pure silicon particles increases, while the internal temperature rise of the battery gradually increases. This is mainly because large-diameter pure silicon particles, due to their larger volume changes during lithium insertion and extraction, are more prone to mechanical stress and thermal effects. This accelerates heat accumulation inside the battery, increasing the battery temperature, and may also lead to particle breakage and pulverization. The reduced electrical contact between pulverized silicon particles and the current collector leads to decreased utilization of the active material, resulting in a decline in battery capacity retention. Therefore, selecting pure silicon particles with an average particle size of 3.0-6.0 μm helps maintain more stable battery performance.

[0152] As shown in Examples 11-16, for the 13350 model cylindrical battery 100, the main adjustment is to the areal density of the negative electrode sheet 10. Table 1 shows that when the areal density of the negative electrode sheet 10 is between 1.6-2.4 mg / cm³... 2When adjusted within the specified range, the capacity of the 13350 model cylindrical battery 100 is consistently above 710mAh. As the areal density of the negative electrode 10 increases, the coating thickness of the negative electrode 10 gradually increases, but remains controlled between 12μm and 20μm. This is mainly because with the increase in the coating thickness of the negative electrode 10, more active material is available, which can increase the battery's lithium storage capacity to some extent, thus contributing to the improvement of battery capacity. As shown in Example 15, when the areal density of the negative electrode 10 is 1.6 mg / cm³... 2 At this point, a lower areal density means less active material per unit area, resulting in a limited number of lithium ions that can be stored and released during charging and discharging, thus leading to the lowest battery capacity. As shown in Example 16, when the areal density of the negative electrode 10 is 2.4 mg / cm³... 2 At the same time, a higher areal density means that more negative electrode active material is loaded on the same area. However, the increase in areal density will also increase the thickness of the negative electrode sheet 10, increase the internal resistance of the battery, thereby affecting the rate performance of the battery and limiting the increase in battery capacity to a certain extent.

[0153] As shown in Examples 17-23, for the 18600 model cylindrical battery 100, the main adjustment is the compaction density of the negative electrode sheet 10. The table shows that when the compaction density of the negative electrode sheet 10 is between 1.10 and 1.30 g / cm³... 3 When adjusted within the specified range, the battery capacity of the 18600 model cylindrical battery 100 is consistently above 2500mAh. As can be seen from Examples 19-21, as the compaction density of the negative electrode sheet 10 increases, the coating thickness of the negative electrode sheet 10 gradually decreases, but remains controlled between 12μm and 20μm. With the decrease in the thickness of the negative electrode sheet 10, the length of the negative electrode sheet 10 increases while maintaining the same battery volume, thus gradually increasing the battery capacity. Examples 17-19 and Examples 21-23 are respectively at 1.10 g / cm³. 3 and 1.30g / cm 3 Test results for batteries with different thicknesses of negative electrode sheet 10 at the compaction density. As the thickness of the negative electrode sheet 10 decreases, the cell capacity shows a decreasing trend, mainly due to the effect of the areal density adjustment.

[0154] As shown in Examples 24-25, the adjustment of the positive electrode active material is mainly for the 18350 cylindrical battery 100. Due to the specific requirements of the e-cigarette industry for high voltage and high rate of discharge, the large-scale application of materials such as lithium iron phosphate and ternary lithium is limited to some extent by their relatively low voltage. The test results of Examples 24-25 show that when pure silicon is used as the negative electrode and lithium cobalt oxide or lithium manganese oxide is used as the positive electrode, the battery capacity is between 1000-1450 mAh. Since lithium manganese oxide has a lower theoretical capacity compared to lithium cobalt oxide, the corresponding battery capacity is also lower. Lithium cobalt oxide has excellent rate performance, with a high capacity retention rate at high discharge rates. Lithium manganese oxide performs poorly at high discharge rates, mainly because the battery temperature rises significantly under high discharge conditions, causing manganese ions to dissolve, thus severely affecting the battery's rate performance.

[0155] As shown in Examples 26-30, the main adjustment for the 18500 model cylindrical battery 100 is the adjustment of the average particle size of the positive electrode active material. The table shows that when the average particle size of the positive electrode material, lithium cobalt oxide, is between 4.5-6.5 μm, the capacity of the 18500 model cylindrical battery 100 in Examples 26-30 is 2250 mAh. This is mainly because the average particle size of high-voltage lithium cobalt oxide can generally reach the range of 16 μm-20 μm, while the average particle size of the lithium cobalt oxide used in this invention is between 4.5-6.5 μm. Smaller particle sizes result in relatively smaller volume changes during charging and discharging, which helps maintain stable battery performance and therefore has less impact on battery capacity. As shown in Example 28, when the particle size of the positive electrode material, lithium cobalt oxide, is greater than 6.0 μm, the rate performance of the battery gradually decreases. This is because as the particle size of the positive electrode material increases, the diffusion path of lithium ions within the material becomes longer, and the diffusion resistance also increases accordingly. This slows down the lithium-ion transport rate during charging and discharging, thus affecting the battery's rate performance. Therefore, selecting lithium cobalt oxide particles with an average particle size of 4.5-6.0 μm helps maintain more stable battery performance.

[0156] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A negative electrode sheet, characterized in that, It includes a negative electrode current collector, a negative electrode tab disposed on the negative electrode current collector, and a negative electrode silicon-based active material; The negative electrode silicon-based active material includes pure silicon particles, and the pure silicon particles have a mass percentage content of 65-100% in the negative electrode silicon-based active material. The negative electrode silicon-based active material forms a first coating surface and a second coating surface on the upper and lower surfaces of the negative electrode current collector, respectively, and the sum of the thicknesses of the first coating surface and the second coating surface is 12μm-20μm.

2. The negative electrode sheet as described in claim 1, characterized in that, The specific capacity of the pure silicon particles is ≥3200mAh / g.

3. A negative electrode sheet as described in claim 2, characterized in that, The average particle size of the pure silicon particles is 3.0-6.0 μm.

4. The negative electrode sheet as described in claim 1, characterized in that, The areal density of the negative electrode sheet is 1.6-2.4 mg / cm³. 2 .

5. A negative electrode sheet as described in claim 4, characterized in that, The compacted density of the negative electrode sheet is 1.1-1.3 g / cm³. 3 .

6. A negative electrode sheet as described in claim 5, characterized in that, The thickness of the negative electrode sheet is 18μm-28μm.

7. A negative electrode sheet as described in claim 1, characterized in that, The first coating surface and the second coating surface each include two negative electrode coating areas. The negative electrode tab is welded in a first blank area between the two negative electrode coating areas of the first coating surface, or the negative electrode tab is welded in a second blank area between the two negative electrode coating areas of the second coating surface.

8. A negative electrode sheet as described in claim 7, characterized in that, The distance between the two coated areas is 2-8 times the width of the negative electrode tab.

9. A negative electrode sheet as described in claim 7, characterized in that, The welding area between the negative electrode tab and the negative electrode sheet is greater than 8mm². 2 .

10. A method for preparing a negative electrode sheet according to any one of claims 1-9, characterized in that, Includes the following steps: A. Pure silicon particle material, conductive agent and binder are uniformly dispersed in a solvent to obtain a negative electrode coating slurry. The solid content of the negative electrode coating slurry is 10-15wt%, and the viscosity of the negative electrode coating slurry is 4000-15000mPa·s. B. The negative electrode coating slurry is coated on the surface of the current collector, and the negative electrode sheet is obtained after drying and rolling.

11. A cylindrical battery, characterized in that, It includes an aluminum-plastic shell, an electrolyte placed inside the shell, and a cylindrical core, wherein the cylindrical core includes a positive electrode, a separator, and a negative electrode as described in any one of claims 1-9.

12. A cylindrical battery as described in claim 11, characterized in that, The positive electrode includes a positive current collector, a positive electrode tab disposed on the positive current collector, and a positive active material, wherein the positive active material is either lithium manganese oxide or lithium cobalt oxide.

13. A cylindrical battery as described in claim 12, characterized in that, The proportion of lithium cobalt oxide in the positive electrode active material is 80-100 wt%.

14. A cylindrical battery as described in claim 13, characterized in that, The average particle size of the lithium cobalt oxide is 4.5-6.0 μm.

15. A cylindrical battery as described in claim 12, characterized in that, The positive electrode active material forms a third coating surface and a fourth coating surface on the upper and lower surfaces of the positive electrode current collector, respectively; the third coating surface and the fourth coating surface each include two positive electrode coating areas, and the positive electrode tab is welded in the third blank area between the two positive electrode coating areas of the third coating surface, or the positive electrode tab is welded in the fourth blank area between the two positive electrode coating areas of the fourth coating surface.

16. A cylindrical battery as described in claim 15, characterized in that, The positive electrode has a length of 745-750mm and a width of 20-25mm; the negative electrode has a length of 800-805mm and a width of 20-25mm; the cylindrical battery has a capacity of 580-700mAh at a discharge rate of 0.2C.

17. A cylindrical battery as described in claim 15, characterized in that, The positive electrode has a length of 745-750mm and a width of 25-30mm; the negative electrode has a length of 800-805mm and a width of 25-30mm; the cylindrical battery has a capacity of 710-810mAh at a discharge rate of 0.2C.

18. A cylindrical battery as described in claim 15, characterized in that, The positive electrode has a length of 745-750mm and a width of 30-35mm; the negative electrode has a length of 800-805mm and a width of 30-35mm; the cylindrical battery has a capacity of 820-920mAh at a discharge rate of 0.2C.

19. A cylindrical battery as described in claim 15, characterized in that, The positive electrode has a length of 1300-1320mm and a width of 25-35mm; the negative electrode has a length of 1360-1380mm and a width of 25-35mm; the cylindrical battery has a capacity of 1000-1600mAh at a discharge rate of 0.2C.

20. A cylindrical battery as described in claim 15, characterized in that, The positive electrode has a length of 1300-1320mm and a width of 40-45mm; the negative electrode has a length of 1360-1380mm and a width of 40-45mm; the cylindrical battery has a capacity of 2100-2400mAh at a discharge rate of 0.2C.

21. A cylindrical battery as described in claim 15, characterized in that, The positive electrode has a length of 1300-1320mm and a width of 50-55mm; the negative electrode has a length of 1360-1380mm and a width of 50-55mm; the cylindrical battery has a capacity of 2500-2900mAh at a discharge rate of 0.2C.

22. An electronic cigarette, characterized in that, Including a cylindrical battery as described in any one of claims 11-21.

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