Lithium ion cylindrical battery, method of manufacturing the same, and electric device
By applying a protective film to the flattened layer of a lithium-ion cylindrical battery and then peeling it off during transport, the problem of dust contamination and mechanical damage to the flattened layer during transport is solved, thus achieving improved battery performance with lower internal resistance, higher charge/discharge rates, and longer cycle life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU RELIANCE ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2026-04-23
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, during the transfer of lithium-ion cylindrical batteries after flattening, the end face of the flattened layer is easily contaminated by dust and mechanically damaged, affecting battery performance and safety.
The smoothing layer is sealed with a protective film. The protective film is applied to the end face of the core using a film-applying device, and then peeled off during transportation using a film-peeling device to ensure that the smoothing layer is not contaminated or damaged.
It effectively avoids dust pollution and mechanical damage, improves the battery's low internal resistance, high-rate charge and discharge and long cycle life performance, increases the cell qualification rate and reduces production costs.
Smart Images
Figure CN122393429A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery technology, and in particular to a lithium-ion cylindrical battery, its preparation method, and an electrical device thereof. Background Technology
[0002] For lithium-ion cylindrical batteries, especially all-tab cylindrical batteries, the quality of the end faces of the cell tabs after flattening is crucial to ensuring the final performance and safety of the battery. This is typically achieved by improving the flattening precision and implementing post-flattening dust removal to eliminate dust generated during the flattening process, thereby resulting in cells with lower internal resistance and higher reliability.
[0003] In the existing technology, in order to realize the transfer of the flattened battery cell to the subsequent casing and packaging process, the relevant technologies usually adopt conventional transfer methods, such as direct transfer and transportation through ordinary material boxes or belt conveyors; however, this method directly exposes the flattened end face of the battery cell to the external environment. The end face of the battery cell is exposed for a period of time, which can easily affect the final performance of the battery.
[0004] Therefore, how to obtain a lithium-ion cylindrical battery with low internal resistance, high charge-discharge rate, and long cycle life has become an important research topic. Summary of the Invention
[0005] In view of this, the present invention aims to at least partially solve one of the technical problems in the related art. To this end, the present invention provides a lithium-ion cylindrical battery and its preparation method, as well as an electrical device thereof, which can effectively avoid the impact of dust contamination on the internal structure of the battery, ensuring that the battery has properties such as low internal resistance, high-rate charge / discharge, and long cycle life.
[0006] To solve the above-mentioned technical problems, the present invention is implemented as follows: According to one aspect of the present invention, a lithium-ion cylindrical battery is provided, comprising: case; A core is disposed in the housing; the core includes a laminate, the laminate being wound in a winding direction to form the core; the laminate includes a positive electrode sheet, a separator, and a negative electrode sheet stacked sequentially; the positive electrode sheet has at least one positive electrode tab on at least one side in the width direction, and the negative electrode sheet has at least one negative electrode tab on the other side in the width direction; A flattening layer is disposed on at least one end of the core; the flattening layer includes a positive electrode flattening layer and a negative electrode flattening layer, the positive electrode tab is formed by pressing to form the positive electrode flattening layer, and the negative electrode tab is formed by pressing to form the negative electrode flattening layer; The number of dust particles on the surface of the kneaded layer is 'a', in units of particles; 'a' satisfies: a≤150; The particle size of the dust particles is 5μm to 15μm.
[0007] In some embodiments, the surface area of the kneaded layer is S = 320 mm². 2 ≤S≤350mm 2 .
[0008] In some embodiments, the surface of the smoothed layer contains b scratches, in units of scratches; The condition b satisfies: b≤0; The length of the scratch is 0.5mm to 2mm.
[0009] According to another aspect of the present invention, a method for preparing a lithium-ion cylindrical battery is provided, comprising the following steps: The prepared positive electrode sheet, separator and negative electrode sheet are stacked in sequence to form a laminate; the laminate is then wound in the winding direction to form a core. The tabs on the end face of the core are squeezed to form a flattened layer; wherein, the tabs include positive tabs and negative tabs; the flattened layer includes a positive flattened layer and a negative flattened layer; The core is placed on the film-applying device, a protective film is applied to the end face of the core, the core with the protective film applied is placed into the housing, and the protective film is peeled off using the film-peeling device.
[0010] In some embodiments, the protective film has the same shape as the end face of the core.
[0011] In some embodiments, the material of the protective film includes at least one of polyethylene terephthalate, polypropylene, and polyethylene.
[0012] In some embodiments, the thickness of the protective film is 0.03 mm to 0.05 mm.
[0013] In some embodiments, the radius of any end face of the core is R1, and the radius of the protective film is R2; Wherein, 1.1≤R2 / R1≤1.5.
[0014] In some of these embodiments, the value of R1 ranges from 19.5 mm to 21 mm.
[0015] In some of these embodiments, the value of R2 ranges from 21.45 mm to 31.5 mm.
[0016] In some embodiments, during the film application process, the film application device includes a film-pressing roller, the pressure applied by the film-pressing roller is 0.1MPa~0.5MPa, and the temperature of the film-pressing roller is 30℃~60℃.
[0017] In some embodiments, the peeling device peels off the protective film at an angle of 90° to 180° and at a speed of 10 mm / s to 50 mm / s.
[0018] In some embodiments, the surface of the pressing roller is provided with an elastomer, the hardness of which is 40 Shore A to 60 Shore A.
[0019] According to another aspect of the present invention, an electrical device is provided, comprising: a lithium-ion cylindrical battery as described in any of the above embodiments; And / or, lithium-ion cylindrical batteries prepared by the preparation method described in any of the above embodiments.
[0020] Implementing the technical solution of the present invention has at least the following beneficial effects: 1. In this invention, by limiting the number of dust particles on the surface of the core flattening layer, the stability of battery performance can be better guaranteed: the impact of end face damage and dust pollution on the internal structure of the battery can be avoided, ensuring the core performance of the battery such as low internal resistance, high rate charge and discharge, and long cycle life, thereby improving product quality.
[0021] 2. In the preferred embodiment of the present invention, the pass rate of cylindrical battery cells is effectively improved, secondary dust pollution and mechanical impact damage are reduced, and the pass rate of cells is increased by more than 8% (taking the 21700 model as an example, from 90.5% to 99.2%), which significantly reduces the amount of scrapped cells and lowers production costs.
[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description
[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0024] Figure 1 The diagram shown is a schematic diagram of the laminated structure provided by the present invention.
[0025] Figure 2 The diagram shown is a schematic diagram of the core structure provided by the present invention.
[0026] Figure 3 The diagram shows the end face of the core and the protective film provided by the present invention.
[0027] Explanation of reference numerals in the attached figures: 100 – Laminated body; 100a – Core; 101 – Positive electrode tab; 102 – Negative electrode tab; 110 – Flattened layer; 111 – Positive electrode flattened layer; 112 – Negative electrode flattened layer; 200 – Protective film.
[0028] The accompanying drawings have illustrated specific embodiments of the invention, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art through reference to particular embodiments. Detailed Implementation
[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.
[0030] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges or individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.
[0031] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.
[0032] Unless otherwise specified, all technical features and optional technical features of this invention can be combined to form new technical solutions.
[0033] 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. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.
[0034] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.
[0035] Currently, in the manufacturing process of lithium-ion cylindrical batteries, especially all-tab cylindrical batteries, the common practice to achieve continuous transfer of cells from the leveling process to the casing and packaging process is to directly transfer and buffer the leveled cells using open material boxes, trays, or belt conveyors. Specifically, this approach uses mechanical handling equipment to grab or push the cells, moving them a certain distance in an open environment. Its basic working principle is to physically transport the cells from one workstation to the next using a material conveying system. Its widespread application is mainly due to its ability to achieve a simple and continuous production process and high transfer efficiency.
[0036] However, this solution performs poorly when applied to a specific scenario where the flattened battery cells require 0.5 to 2 hours of multi-stage transfer and temporary storage. A fundamental contradiction lies in the fact that, in order to optimize the continuity of its transfer process and the versatility of its equipment, the inherent design of this solution inevitably compromises the isolation and protection of the critical parts of the battery cell—namely, the fragile flattened layer end face—and may even lead to secondary contamination and physical damage. Specifically, on the battery production line, the flattened layer end face of the battery cell is directly exposed to the production environment during this transfer cycle, making it susceptible to adhesion from floating dust particles. Simultaneously, mechanical contact, collisions, and friction between the battery cell and the transfer carrier (such as the inner wall of the material box) or adjacent cells can cause scratches, dents, or powder shedding on the flattened layer surface. These problems directly affect the bonding accuracy and welding quality of subsequent encapsulation, thereby threatening the internal resistance, rate performance, and safety reliability of the battery product.
[0037] Therefore, it is of great significance to obtain a lithium-ion cylindrical battery with a high-quality flattened layer at its end face, thereby enabling the battery to have good overall performance.
[0038] In view of the technical problems existing in the prior art, the present invention provides a lithium-ion cylindrical battery and its preparation method and power device, which can effectively avoid the impact of dust pollution on the internal structure of the battery and ensure that the battery has performance such as low internal resistance, high rate charge and discharge and long cycle life.
[0039] The specific technical solution of the present invention is as follows: In some embodiments of the present invention, a lithium-ion cylindrical battery is provided, comprising: a casing, a core 100a, and a flattening layer 110; the core 100a is disposed in the casing; the core 100a includes a laminate 100, the laminate 100 being wound in a winding direction to form the core 100a; the laminate 100 includes a positive electrode sheet, a separator, and a negative electrode sheet stacked sequentially; the positive electrode sheet has at least one positive electrode tab 101 on at least one side in the width direction, and the negative electrode sheet has at least one negative electrode tab 102 on the other side in the width direction; the flattening layer 110 is disposed on at least one end of the core 100a; the flattening layer 110 includes a positive electrode flattening layer 111 and a negative electrode flattening layer 112, the positive electrode tab 101 being formed by pressing to form the positive electrode flattening layer 111, and the negative electrode tab being formed by pressing to form the negative electrode flattening layer 112.
[0040] Furthermore, the number of dust particles on the surface of the leveling layer 110 is denoted as 'a', with the unit being 'particles'; 'a' satisfies the condition: a≤150; wherein the particle size of the dust particles is 5μm~15μm.
[0041] As an example, see reference Figure 1 , Figure 2 and Figure 3 The positive electrode sheet includes a positive current collector and a positive active coating on at least one surface of the positive current collector in the thickness direction. The positive active coating includes a positive electrode material, a conductive agent, and a binder. The positive electrode material includes, but is not limited to, lithium iron phosphate, lithium manganese iron phosphate, and ternary materials. The conductive agent can be SP conductive agent, carbon nanotubes, etc., and the binder can be polyvinylidene fluoride, etc. The negative electrode sheet includes a negative current collector and a negative active coating on at least one surface of the negative current collector in the thickness direction. The negative active coating includes a negative electrode material, a conductive agent, and a binder. The negative electrode material includes silicon carbide materials, graphite, hard carbon, etc., and the binder can be sodium carboxymethyl cellulose, etc. The specific components of the above positive and negative electrode sheets are not specifically limited here.
[0042] Further, the positive electrode sheet, separator, and negative electrode sheet are stacked sequentially to form a laminate 100. The laminate 100 is then wound in a winding direction to obtain a core 100a. It can be understood that the winding direction is the length direction of the unfolded positive electrode sheet, negative electrode sheet, or separator. One or more positive electrode tabs 101 are provided on one or both sides of the positive electrode sheet in the width direction. Similarly, one or more negative electrode tabs 102 are provided on one or both sides of the negative electrode sheet in the width direction. After forming the core 100a, at the ends of the core 100a, i.e., on one or both sides of the core 100a in the width direction, the positive electrode tabs 101 are pressed to form a positive electrode flattened layer 111, and the negative electrode tabs 102 are pressed to form a negative electrode flattened layer 112. The positive electrode flattened layer 111 and the negative electrode flattened layer 112 may or may not be at the same end in the width direction of the core 100a.
[0043] Optionally, the lithium-ion cylindrical battery includes a full-tab cylindrical battery, which includes a positive electrode, a negative electrode, and a separator. As an example, the positive electrode includes a positive current collector and a positive active coating disposed on at least one surface of the positive current collector along its thickness direction. The phrase "positive active coating disposed on at least one surface of the positive current collector" means that the positive active coating can be disposed on one surface or two surfaces of the positive current collector along its thickness direction. Here, "surface" can refer to the entire area of the positive current collector or only a portion of it; this application does not impose any particular limitation, as long as the purpose of this application is achieved. In this application, the separator is not particularly limited, as long as the purpose of this application is achieved; optionally, the separator includes, but is not limited to, at least one polymer separator selected from polyethylene, polypropylene, polyacrylonitrile, polysulfonyl, polyarylethersulfone, polyvinyl alcohol, and polyvinylidene fluoride.
[0044] Furthermore, the number 'a' of dust particles on the surface of the flattened layer 110 can be any one of 0, 10, 20, 50, 100, 120, 140, or 150, or any value between any two. The particle size can be any value of 5μm, 8μm, 10μm, 12μm, or 15μm. By controlling the range of dust particle counts on the flattened layer 100 at the end face of the core 100a, the battery can be effectively protected, preventing problems such as internal short circuits and poor contact of the electrode tabs, thereby improving battery safety and cycle life. It is also understood that the particle size and number of the aforementioned dust particles can be measured under magnification using SEM (scanning electron microscopy) or a microscope.
[0045] In some embodiments, the surface area of the flattening layer 110 is S = 320 mm². 2 ≤S≤350mm 2 For example, the surface area S of the leveled layer can be 320 mm². 2 322mm 2 325mm 2 328mm 2 330mm 2 335mm 2 338mm 2 340mm 2 342mm 2 345mm 2 348mm 2 349mm 2 Or 350mm 2 Any point value in either or between any two of them.
[0046] In some embodiments, the surface of the flattening layer 110 contains a number of scratches, b, in units of scratches; b satisfies: b≤0; wherein the length of the scratches is 0.5mm~2mm.
[0047] As an example, the number of scratches on the surface of the flattening layer 110 within the range of 0.5mm, 1mm, 1.5mm, 1.8mm or 2mm can be 0. By limiting the above range of scratches, problems such as tab breakage and damage to the flattening layer 110 can be effectively prevented. This further protects the integrity of the flattening layer 110, and improves the bonding accuracy of the core 100a when it is subsequently installed into the housing, thereby solving problems such as poor welding and battery leakage.
[0048] In some embodiments of the present invention, a method for preparing a lithium-ion cylindrical battery is provided, comprising the following steps: S101. The prepared positive electrode sheet, separator and negative electrode sheet are stacked in sequence to form a laminate 100; the laminate 100 is wound in the winding direction to form a core 100a.
[0049] S102. The tabs on the end face of the core 100a are squeezed to form a flattened layer; wherein, the tabs include positive tabs and negative tabs; the flattened layer includes a positive flattened layer and a negative flattened layer.
[0050] S103. Place the core 100a on the film application device, apply a protective film 200 to the end face of the core 100a, place the core with the protective film 200 applied into the housing, and peel off the protective film using the film peeling device.
[0051] As an example, the film application device may include a cell positioning component, a protective film supply component, and a film application execution component. The cell positioning component may employ a three-jaw centering clamp, adaptable to different models of all-tab cylindrical cells such as 21700 and 46800, with a positioning accuracy of ±0.05mm, ensuring precise alignment between the end face of the core 100a and the protective film 200. The protective film supply component may include a protective film roll, guide rollers, and an automatic cutting mechanism. The protective film 200 is made of flexible transparent PET (polyethylene terephthalate) film, coated with a residue-free coating, and its cutting size matches the end face of the core 100a, ensuring complete coverage of the smoothing layer 110. The film application execution component may employ a pneumatic pressure head with a flexible rubber pad on its surface to prevent excessive pressure from damaging the smoothing layer, while ensuring tight film application without bubbles or wrinkles, preventing the protective film 200 from falling off during transport.
[0052] Optionally, the film-unwrapping device includes film-unwrapping grippers, a traction component, and a recycling component. The film-unwrapping grippers can be flexible silicone grippers, which can accurately hold the edge of the protective film 200 and avoid damaging the end face of the core 100a and the flattened layer 110. The traction component can be driven by a servo motor, and the traction speed is synchronized with the conveying speed of the core 100a to ensure smooth film unwrapping without pulling the flattened layer 110. The recycling component can include a recycling roll and a drive motor, which can concentrate and recycle the removed protective film 200 to avoid environmental pollution and reduce consumable costs.
[0053] In some embodiments, the protective film 200 has the same shape as the end face of the core 100a.
[0054] As an example, the shape of the protective film 200 can be the same as the end face shape of any end of the core 100a, thereby effectively protecting the flattening layer 110 from contamination.
[0055] In some embodiments, the material of the protective film 200 includes, but is not limited to, one or more of polyethylene terephthalate, polyethylene, and polypropylene.
[0056] In some embodiments, the thickness of the protective film 200 is 0.03 mm to 0.05 mm. Exemplarily, the thickness of the protective film 200 can be any one of 0.03 mm, 0.04 mm, or 0.05 mm, or any value between any two. The thickness of the protective film can be measured using a vernier caliper or a micrometer.
[0057] In some embodiments, the radius of any end face of the core 100a is R1, and the radius of the protective film 200 is R2; wherein 1.1 ≤ R2 / R1 ≤ 1.5. Exemplarily, the ratio of the radius of the protective film 200 to the end face of any end of the core 100a, i.e., R2 / R1, can be any one of 1.1, 1.2, 1.3, 1.4, or 1.5, or any value between any two. By limiting the range of R2 / R1, the protective film 200 can be effectively adhered to the end face of the core 100a, ensuring that the protective film 200 effectively protects the flattened layer 110 of the end face of the core 100a. Simultaneously, the protective film 200 can be easily removed before the core 100a is installed into the housing, preventing damage to the core 100a during removal.
[0058] In some embodiments, the value of R1 ranges from 19.5mm to 21mm. For example, R1 can be any one of 19.5mm, 19.8mm, 20mm, 20.2mm, 20.5mm or 21mm or any point value between any two of them.
[0059] In some embodiments, the value of R2 ranges from 21.45mm to 31.5mm. For example, R2 can be any one of 21.45mm, 21.5mm, 22mm, 24mm, 25mm, 28mm, 29mm, 30mm, 31mm or 31.5mm, or any point value between any two of them.
[0060] In some embodiments, during the film application process, the film application device includes a pressure roller, the pressure applied by the pressure roller is 0.1 MPa to 0.5 MPa, and the temperature of the pressure roller is 30°C to 60°C. Exemplarily, the pressure applied by the pressure roller can be any one of 0.1 MPa, 0.2 MPa, 0.4 MPa, or 0.5 MPa, or any value between any two; the temperature of the pressure roller can be any one of 30°C, 35°C, 40°C, 50°C, or 60°C, or any value between any two.
[0061] In some embodiments, the peeling device peels off the protective film at an angle of 90° to 180° and at a speed of 10 mm / s to 50 mm / s. For example, the peeling angle can be any one of 90°, 100°, 120°, 150°, or 180°, or any value between any two; the peeling speed can be any one of 10 mm / s, 20 mm / s, 30 mm / s, 40 mm / s, or 50 mm / s, or any value between any two.
[0062] In some embodiments, the surface of the pressure roller is provided with an elastomer, the hardness of which is 40 Shore A to 60 Shore A. Exemplarily, the hardness of the elastomer can be any value between 40 Shore A, 45 Shore A, 50 Shore A, or 60 Shore A.
[0063] In some embodiments of the present invention, an electrical device is provided, comprising: a lithium-ion cylindrical battery as described in any of the above embodiments.
[0064] In some embodiments, the power device comprises a lithium-ion cylindrical battery prepared by the preparation method described in any of the above embodiments.
[0065] Since the battery provided in this embodiment of the invention adopts all the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be described in detail here.
[0066] As examples, electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, power tools, energy storage devices, amusement equipment, elevators and lifting equipment, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, or electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices can be energy storage walls, base station energy storage, container energy storage, etc.; amusement equipment can be carousels, drop towers, etc. The aforementioned vehicles can be gasoline-powered vehicles, natural gas-powered vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. The vehicle has a battery installed inside, which can be located at the bottom, front, or rear of the vehicle. The battery can be used to power the vehicle; for example, the battery can serve as the vehicle's operating power source. The vehicle may also include a controller and a motor. The controller controls the battery's power supply to the motor, for example, to meet the vehicle's power needs during starting, navigation, and driving. The battery can serve not only as the vehicle's operating power source but also as its driving power source, replacing or partially replacing fuel or natural gas to provide propulsion.
[0067] The present application will be specifically described below with reference to examples, but the implementation and protection of the present invention are not limited thereto. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.
[0068] Example 1 Positive electrode preparation: 96.2% of the positive electrode active material LiNi 0.6 Co 0.2 Mn 0.2 O2, 2% polyvinylidene fluoride (PVDF) and 1.8% SP were added to the solvent NMP (N-methylpyrrolidone) and stirred to obtain a positive electrode slurry with a solid content of 68%. The slurry was then coated on both sides of an aluminum foil and dried to obtain a positive electrode sheet.
[0069] Negative electrode preparation: 96% artificial graphite and silicon carbide (artificial graphite and silicon carbide mass ratio of 85%:15%), 1.0% SP, 1.0% thickener (CMC, sodium carboxymethyl cellulose) and 2.0% SBR (styrene-butadiene rubber) are added to deionized water and stirred to obtain a negative electrode slurry with a solid content of 40%. The slurry is then coated on both sides of copper foil and dried to obtain a negative electrode sheet.
[0070] The membrane consists of a high-porosity PE base membrane and ceramic coatings on opposite sides of the base membrane. The PE base membrane is 9 μm thick, and the ceramic coatings on both sides are 1 μm thick. PVDF is used as a binder to bond the ceramic coatings to the surface of the base membrane. The PVDF coating is 1 μm thick.
[0071] Electrolyte: Lithium salt LiPF6 is dissolved in an organic solvent, which is prepared by mixing ethylene carbonate (EC), diethyl carbonate (DEC) and methyl ethyl carbonate in a volume ratio of 1:1:1, and finally prepared into an electrolyte with a lithium salt concentration of 1 mol / L.
[0072] Battery Assembly: After the positive and negative electrode sheets are slit and die-cut using a winding machine, they are wound together with the separator to form a core. The core is then cut and stacked with positive and negative electrode tabs. The positive and negative busbars are then welded to the core, and the negative busbar is welded to the steel shell. An insulating sheet is placed on top of the positive busbar, and the positive busbar is welded to the cap. Next, grooving, electrolyte injection, and sealing are completed. Finally, a formation process yields the experimental full-tab cylindrical battery.
[0073] The differences between Examples 2 to 8 and Comparative Examples 1 and 2 are only as shown in Table 1.
[0074] Performance testing: 1. Dust particle count: Cover the flattened end face of the battery cell with a clean dust collection paper, apply pressure of about 1-3 kg for 5-10 seconds to allow the dust to be fully transferred to the paper, and then collect the number of foreign particles in the area through a microscope.
[0075] 2. Internal resistance: Apply a weak AC signal with a fixed frequency (usually 1kHz) and a fixed current (usually in the range of 50mA or 100mA) to the battery, measure the change in AC voltage generated, and then calculate the internal resistance.
[0076] 3. Rate performance: The test is usually conducted in a constant temperature environment (e.g., 25℃±2℃) using a battery charge and discharge tester.
[0077] 4. Cyclic performance: At a set temperature (e.g., 25℃±2℃), the battery is repeatedly charged and discharged hundreds or thousands of times using a battery charge and discharge tester until the battery capacity decays to a specified value (usually 80% of the initial capacity). The total number of cycles recorded is the cycle life.
[0078] The test results are shown in Table 1.
[0079] Table 1 The parts of this invention not described in detail are techniques known to those skilled in the art.
[0080] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.
[0081] It should be noted that the terms "and / or" or " / " used herein are merely descriptions of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The singular forms "a," "described," and "the" used in the embodiments of the invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.
[0082] In the detailed description and claims, a list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms may mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another example, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single element or multiple elements. Item B may contain a single element or multiple elements. Item C may contain a single element or multiple elements.
[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A lithium-ion cylindrical battery, characterized in that, include: case; A core is disposed in the housing; the core includes a laminate, the laminate being wound in a winding direction to form the core; the laminate includes a positive electrode sheet, a separator, and a negative electrode sheet stacked sequentially; the positive electrode sheet has at least one positive electrode tab on at least one side in the width direction, and the negative electrode sheet has at least one negative electrode tab on the other side in the width direction; A flattening layer is disposed on at least one end of the core; the flattening layer includes a positive electrode flattening layer and a negative electrode flattening layer, the positive electrode tab is formed by pressing to form the positive electrode flattening layer, and the negative electrode tab is formed by pressing to form the negative electrode flattening layer; The number of dust particles on the surface of the kneaded layer is 'a', in units of particles; 'a' satisfies: a≤150; The particle size of the dust particles is 5μm to 15μm.
2. The lithium-ion cylindrical battery according to claim 1, characterized in that, The surface area of the kneaded layer is S = 320 mm². 2 ≤S≤350mm 2 .
3. The lithium-ion cylindrical battery according to claim 1, characterized in that, The number of scratches on the surface of the smoothed layer is b, in units of scratches; The condition b satisfies: b≤0; The length of the scratch is 0.5mm to 2mm.
4. A method for preparing a lithium-ion cylindrical battery as described in any one of claims 1 to 3, characterized in that, Includes the following steps: The prepared positive electrode sheet, separator and negative electrode sheet are stacked in sequence to form a laminate; the laminate is then wound in the winding direction to form a core. The tabs on the end face of the core are squeezed to form a flattened layer; wherein, the tabs include positive tabs and negative tabs; the flattened layer includes a positive flattened layer and a negative flattened layer; The core is placed on the film-applying device, a protective film is applied to the end face of the core, the core with the protective film applied is placed into the housing, and the protective film is peeled off using the film-peeling device.
5. The method for preparing a lithium-ion cylindrical battery according to claim 4, characterized in that, The shape of the protective film is the same as the shape of the end face of the core. And / or, the material of the protective film includes at least one of polyethylene terephthalate, polypropylene, and polyethylene; And / or, the thickness of the protective film is 0.03mm~0.05mm.
6. The method for preparing a lithium-ion cylindrical battery according to claim 4 or 5, characterized in that, The radius of any end face of the core is R1, and the radius of the protective film is R2; Wherein, 1.1≤R2 / R1≤1.
5.
7. The method for preparing a lithium-ion cylindrical battery according to claim 6, characterized in that, The value of R1 ranges from 19.5mm to 21mm; And / or, the value of R2 ranges from 21.45mm to 31.5mm.
8. The method for preparing a lithium-ion cylindrical battery according to claim 4, characterized in that, During the film application process, the film application device includes a film-pressing roller, the pressure applied by the film-pressing roller is 0.1MPa~0.5MPa, and the temperature of the film-pressing roller is 30℃~60℃; And / or, during the process of peeling off the protective film, the peeling angle of the peeling device is 90°~180° and the peeling speed is 10mm / s~50mm / s.
9. The method for preparing a lithium-ion cylindrical battery according to claim 9, characterized in that, The surface of the pressing roller is provided with an elastomer, and the hardness of the elastomer is 40 Shore A to 60 Shore A.
10. An electrical appliance, characterized in that, include: The lithium-ion cylindrical battery according to any one of claims 1 to 3; And / or, a lithium-ion cylindrical battery prepared by the preparation method according to any one of claims 4 to 9.