Battery

Abstract

The invention relates to the technical field of batteries, in particular to a battery which comprises a positive plate, a negative plate and a diaphragm, the diaphragm is located between the positive plate and the negative plate, in the thickness direction of the positive plate, the positive plate comprises a first surface and a second surface which are opposite to each other, the first surface comprises a plurality of concave parts, and the depth D2 of each concave part is 3-50 microns; the diaphragm comprises a base material layer and an organic coating located on at least one side surface of the base material layer, and the organic coating comprises organic particles. Through the synergistic effect of the organic coating of the diaphragm and the concave part structure of the positive plate, the high-temperature safety performance of the battery can be remarkably improved and the furnace temperature tolerance of the battery can be improved on the premise of not sacrificing the voltage stability and impedance performance in the high-temperature cycle process, so that the increasingly stringent high-temperature application requirement is met.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a battery. Background Technology

[0002] With the development of the new energy industry, lithium-ion batteries are widely used in electric vehicles, energy storage systems, and portable electronic devices due to their advantages such as high energy density and long cycle life. The furnace temperature performance of a battery, namely its thermal stability and operating efficiency at high temperatures, is crucial to its safety and reliability. Improving this performance is essential for enhancing overall battery performance, extending lifespan, and preventing thermal runaway accidents.

[0003] However, current battery material and structural design face severe challenges. The core contradiction lies in the difficulty of balancing cycle voltage drop and cycle impedance under high-temperature conditions. This is because high temperatures accelerate electrode material degradation, electrolyte decomposition, and interfacial side reactions, leading to increased internal resistance, expanded voltage drop, and reduced output efficiency. On the other hand, the adoption of high-stability electrolytes and high-temperature resistant separators can affect the kinetics of the electrode-electrolyte interface, exacerbating impedance growth during high-temperature cycling, thereby limiting the battery's high-rate performance and long-cycle stability.

[0004] In existing technologies, high-temperature performance of batteries can be improved through material modification, electrolyte additives, or thermal management optimization. However, these methods often struggle to achieve an effective balance between maintaining low cycle voltage drop, controlling impedance growth, and improving high-temperature safety. Therefore, there is an urgent need to develop a new type of battery that can significantly improve high-temperature safety performance while ensuring high-temperature cycle voltage stability and low cycle impedance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a battery. Through the synergistic effect of the organic coating on the separator and the recessed structure of the positive electrode, the high-temperature safety performance of the battery can be significantly improved without sacrificing voltage stability and impedance during high-temperature cycling, thereby enhancing the battery's furnace temperature tolerance and meeting increasingly stringent high-temperature application requirements.

[0006] A first aspect of the present invention provides a battery comprising a positive electrode, a negative electrode, and a separator, the separator being located between the positive electrode and the negative electrode. In the thickness direction of the positive electrode, the positive electrode includes a first surface and a second surface facing away from each other. The first surface includes a plurality of recesses, the depth D of which is... 2 The range is 3μm-50μm; The membrane includes a substrate layer and an organic coating located on at least one surface of the substrate layer. The organic coating includes organic particles, and the organic particles include a first compound whose molecular structure includes a nitrogen-containing fused heterocycle, the nitrogen-containing fused heterocycle being selected from one or more of the following structures: (I) (II) (III) (IV) (V) (VI); The battery satisfies the following relationship: 4.4 ≤ D 2 / D 1 ≤950, where D 1 Dv10 of the organic particles, in μm. 2 The depth of the concave portion is expressed in μm.

[0007] By employing the above technical solution, the present invention has at least the following advantages compared with the prior art: This invention achieves synergistic control of the Dv10 (D) of organic particles in the organic coating of the diaphragm. 1 ) and the depth of the concave portion of the positive electrode (D) 2 ), such that both satisfy 4.4≤D 2 / D 1 With a temperature ≤950°C, an optimized balance between battery furnace temperature performance and high-temperature electrochemical performance can be achieved. A suitable recess depth can store sufficient electrolyte, effectively promoting interfacial heat dissipation and significantly improving the battery's furnace temperature tolerance. Matching-sized organic particles undergo controllable micro-dissolution in the electrolyte, and the dissolved molecules migrate to the surface of the positive electrode active material to form a stable complex protective layer. This layer not only suppresses side reactions between the positive electrode and electrolyte at high temperatures and improves material structural stability, thus preventing increased internal resistance and voltage drop, but also fills micro-cracks that may occur during the setting of the recess in the positive electrode sheet, preventing particle breakage and puncture of the separator, thus avoiding short circuits. These two aspects work synergistically to enhance the battery's high-temperature thermal stability while reducing voltage drop and impedance growth during high-temperature cycling, thereby ensuring the safety and reliability of the battery during high-temperature use and significantly improving its furnace temperature tolerance.

[0008] Other features and advantages of the present invention will be described in detail in the following detailed description section.

[0009] 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 and 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. Attached Figure Description

[0010] Figure 1 The image shown is an SEM image of an organic coating provided in an embodiment of the present invention. Detailed Implementation

[0011] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the invention. Unless otherwise specified herein, data ranges include endpoints.

[0012] It should be noted that the numerical designations such as "first" and "second" in this invention are only used to distinguish different substances or methods of use, and do not represent a difference in order.

[0013] A first aspect of the present invention provides a battery comprising a positive electrode, a negative electrode, and a separator, the separator being located between the positive electrode and the negative electrode. In the thickness direction of the positive electrode, the positive electrode includes a first surface and a second surface facing away from each other. The first surface includes a plurality of recesses, the depth D of which is... 2 The range is from 3μm to 50μm, for example, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 41μm, 42μm, 43μm, 44μm, 45μm, 46μm, 47μm, 48μm, 49μm, or 50μm. In some instances, the depth D of the recess 2The depth is 5μm-35μm. In this invention, the plurality of recesses on the first surface of the positive electrode sheet can be obtained using conventional techniques in the art, such as by using an embossing roller (with raised dots) through an embossing process. In this invention, the depth of the recess refers to the maximum vertical distance from any point at the bottom of the recess to the surface of the positive electrode sheet in the thickness direction of the positive electrode sheet. When the number of recesses is greater than 1, the depth of the recess is the average depth; for example, when the number of recesses is less than or equal to 20, the depth of the recess is the average depth of all recesses; when the number of recesses is greater than 20, the depth of the recess is the average depth of any 20 recesses.

[0014] The membrane includes a substrate layer and an organic coating located on at least one surface of the substrate layer. The organic coating includes organic particles, and the organic particles include a first compound whose molecular structure includes a nitrogen-containing fused heterocycle, the nitrogen-containing fused heterocycle being selected from one or more of the following structures: (I) (II) (III) (IV) (V) (VI). Nitrogen-containing fused heterocycles are organic molecular compounds with nitrogen atoms as heteroatoms and containing two or more ring structures. The lone pair electrons of the nitrogen atom can form coordination bonds with metal ions on the surface of the positive electrode active material, allowing the nitrogen-containing fused heterocycle molecules to adsorb on the positive electrode surface and form a dense complex protective layer. This blocks the direct contact between the positive electrode and the electrolyte and suppresses high-temperature side reactions in the battery. Moreover, the nitrogen-containing fused heterocycles have two or more ring structures, and the conjugated π bonds make them stable at high temperatures, making them less prone to bond breakage or molecular decomposition. This allows them to maintain the integrity of the protective layer for a long time and improve the thermal safety of the complex protective layer.

[0015] The battery satisfies the following relationship: 4.4 ≤ D 2 / D 1 ≤950, for example, 4.4, 4.5, 5, 5.5, 6, 6.5, 7, 8, 9, 10, 20, 30, 40, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, or 950, where D 1 Dv10 of the organic particles, in μm. 2 D represents the depth of the concave portion, in μm. In some instances, 10 ≤ D 2 / D 1 ≤600.

[0016] Appropriate recess depth (D) 2 While ensuring sufficient electrolyte storage at the interface between the positive electrode and the separator can effectively promote heat dissipation at the positive electrode interface and thus improve the battery's furnace temperature tolerance, the degradation of the positive electrode active material, electrolyte decomposition, and interfacial side reactions will still be accelerated during high-temperature cycling as the temperature accumulates, leading to an increase in battery internal resistance and voltage drop. Based on this, the present invention adds organic particles containing nitrogen-containing fused heterocyclic molecular structures to the organic coating of the separator. These organic particles can achieve trace dissolution, diffusion, and migration to the surface of the positive electrode active material in the electrolyte. They adhere to the surface of the positive electrode sheet through adsorption and coordination and form a complex protective layer. This protective layer can, on the one hand, suppress the side reactions between the positive electrode active material and the electrolyte at high temperatures and improve the structural stability of the positive electrode active material, thereby avoiding an increase in battery internal resistance and voltage drop during high-temperature cycling. On the other hand, it can fill the microcracks that may be generated in the positive electrode active material particles during the setting of the positive electrode recess, preventing the cracks from expanding during high-temperature cycling and causing particle breakage, thereby avoiding the risk of short circuit caused by broken particles piercing the separator. The two work together to enhance the battery's high-temperature thermal stability while reducing voltage drop and impedance growth during high-temperature cycling, thereby ensuring the safety and reliability of the battery in high-temperature use and significantly improving the battery's furnace temperature tolerance.

[0017] Furthermore, with the depth of the concave portion (D) 2 The matched organic particle size undergoes controllable micro-dissolution in the electrolyte, and the dissolved molecules migrate to the surface of the positive electrode active material, which is beneficial for forming a more stable complex protective layer; therefore, this invention achieves this by synergistically controlling the Dv10 (D...) of the organic particles in the membrane organic coating. 1 ) and the depth of the concave portion of the positive electrode (D) 2 Within a suitable range, the relationship between D and the high-temperature electrochemical performance of the battery can be further optimized to achieve a balance. Specifically, when D... 2 / D 1 When the value is less than 4.4, it means that the particle size of the organic particles is too large relative to the depth of the recessed area of ​​the positive electrode. This imbalance will cause two problems: first, the amount of electrolyte stored at the interface between the positive electrode and the separator is insufficient, resulting in poor interfacial heat dissipation; second, the Dv10 of the organic particles is relatively too large, and their solubility in the electrolyte is insufficient to fully cover the surface of the positive electrode active material, which is not conducive to the stability of the positive electrode active particles under high temperature environment, and the improvement effect on the battery furnace temperature performance is weak; when D... 2 / D 1A value >950 indicates that the depth of the positive electrode recess is relatively large while the particle size of the organic particles is too small. This situation also causes multiple problems: the excessively deep recess will damage the positive electrode active particles, which will reduce the stability of the particles during high-temperature cycling, leading to breakage, detachment, or dissolution of transition metals—causing rapid capacity decay and increasing the risk of broken or detached particles puncturing the separator and causing internal short circuits, further worsening high-temperature cycling impedance and voltage drop; the relatively small Dv10 of the organic particles will cause excessive dissolution at high temperatures, reducing the stability of the separator-positive electrode interface, ultimately significantly increasing the battery interface impedance and high-temperature cycling voltage drop. Therefore, this invention, by setting an appropriate recess depth and organic particle size, makes Dv10... 1 With D 2 Satisfying 4.4≤D 2 / D 1 The formula with a value of ≤950 can further improve the furnace temperature performance of the battery, reduce the high-temperature cycling voltage drop and impedance, and enhance the high-temperature electrochemical performance of the battery.

[0018] In this invention, Dv10 refers to the particle size corresponding to the cumulative particle size distribution reaching 10% in the volumetric particle size distribution of the organic particles. In this invention, the volumetric particle size distribution of the organic particles can be obtained by measuring and statistically processing SEM images of the organic coating surface using image analysis software (e.g., ImageJ, NanoMeasurer, Matlab, etc.). The Dv10 of the organic particles can also be obtained by testing with a laser particle size analyzer. For example, before preparing the diaphragm, the Dv10 of the organic particles can be measured using a laser particle size analyzer within 5 minutes after thorough stirring.

[0019] In some instances, the Dv10 of the organic particles is 0.05 μm to 0.9 μm, for example, 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, 0.5 μm, 0.55 μm, 0.6 μm, 0.65 μm, 0.7 μm, 0.75 μm, 0.8 μm, 0.85 μm, or 0.9 μm. By controlling the Dv10 of organic particles within a suitable particle size range, the specific surface area of ​​the organic particles can be ensured to be moderate. This allows for controlled micro-dissolution in the electrolyte, with dissolved molecules migrating to the positive electrode surface to form a dense complex protective layer, suppressing high-temperature side reactions and filling microcracks caused by embossing. It also avoids the problems of excessive dissolution and compromised membrane interface stability due to excessively small particle size, or insufficient dissolution and incomplete protective layer coverage due to excessively large particle size. Simultaneously, this particle size range ensures uniform dispersion of organic particles in the membrane coating, without affecting the uniformity of membrane permeability and ion transport efficiency, further improving the high-temperature thermal stability of the battery, while reducing high-temperature cycling voltage drop and impedance growth.

[0020] In some instances, the width of the recess is 1mm-5mm, for example, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm.

[0021] In some instances, the morphology of the recess includes one or more of holes, lines, and grooves.

[0022] In this invention, the width of the recess refers to the maximum distance between any two points on the edge line of the recess. When the shape of the recess includes a hole, the width of the recess is the diameter of the hole. When the shape of the recess includes one or more of lines and grooves, the width of the recess refers to the average distance between the two long sides in the orthographic projection of the line and groove onto the surface of the positive electrode sheet. For example, 10 points are randomly selected on any one of the long sides, the width corresponding to each point is measured, and the average value is taken as the average distance between the two long sides. When the number of recesses is greater than 1, the width of the recess is the average width. For example, when the number of recesses is less than or equal to 20, the width of the recess is the average width of all the recesses; when the number of recesses is greater than 20, the width of the recess is the average width of any 20 recesses.

[0023] A suitable width range ensures that the recess stores sufficient electrolyte. However, if the recess is too narrow (<1mm), it hinders heat dissipation at the positive electrode interface; if it is too wide (>5mm), it damages the integrity of the positive electrode active layer, easily causing the active material to detach. This is detrimental to reducing voltage drop and impedance increase during high-temperature cycling. By controlling the width of the recess within a suitable range, the interfacial performance between the positive electrode and the separator can be further optimized, enhancing the synergistic effect with organic particles. Moreover, by controlling the width of the recess within the range of 1mm-5mm, interfacial heat dissipation efficiency can be improved, reducing local high-temperature accumulation. It can also reduce damage to the positive electrode active material particles caused by the embossing process, reducing the generation of microcracks. Combined with the protective layer effect of organic particles, this further suppresses the risk of short circuits, ensuring the voltage stability and low impedance characteristics of the battery during high-temperature cycling.

[0024] In this invention, the width and depth of the recess can be obtained by 3D profilometer or SEM testing.

[0025] In some instances, the battery satisfies the following relationship: 1.5 ≤ M 1 / M 2 ≤80, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40, where M 1 The number of recesses, M, is the area of ​​an optional 25mm × 25mm portion of the first surface. 2 The number of organic particles with a surface area of ​​25 μm × 19 μm and a particle size greater than 3.4 μm, optionally on the surface of the diaphragm, is expressed in units of particles. In some preferred embodiments, 3 ≤ M 1 / M 2 ≤40.

[0026] Excessive density of organic particles with a diameter greater than 3.4 μm is detrimental to the uniformity of gas permeability on the separator surface and also reduces the uniformity of lithium ion permeation along the thickness direction of the separator. Therefore, it is necessary to ensure that the density of organic particles is within a suitable range. Conversely, excessive density of the recesses will reduce the interfacial adhesion between the separator and the electrode, increasing the battery impedance. This invention further controls the number M of the recesses by selectively controlling the area of ​​the first surface to be 25 mm × 25 mm. 1 The number M of organic particles with a surface area of ​​optionally 25 μm × 19 μm and a particle size greater than 3.4 μm, relative to the surface area of ​​the diaphragm. 2 Satisfying 1.5≤M 1 / M 2A concentration ≤80 can ensure a uniform distribution of electrolyte content at the interface caused by embossing, improving the uniformity of lithium ions at the interface. This effectively addresses the problem of uneven lithium ion transport caused by large-diameter organic particles, thereby improving the high-temperature cycle resistance of the battery. Specifically, when M... 1 / M 2 When the value is <1.5, an excessive amount of large organic particles will lead to a decrease in the permeability of the separator and a reduction in the number of recesses. The uniformity of electrolyte distribution provided by the recesses will also decrease, resulting in a limited improvement on the uneven lithium-ion transport caused by large-particle organic particles, which is detrimental to improving the battery's cycle resistance; M 1 / M 2 When the value is greater than 80, the number of recesses is too large, and the increase in electrolyte content exceeds the demand of large-diameter organic particles. Furthermore, an excessive number of recesses will reduce the adhesion between the electrode and the separator, increase the interfacial impedance, and is not conducive to improving the cycle impedance of the battery.

[0027] In some instances, the first surface optionally has an area of ​​25mm × 25mm, and the number of recesses M 1 The number of recesses ranges from 15 to 165, for example, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, and 165. In some preferred embodiments, the first surface optionally has an area of ​​25mm × 25mm, and the number M of the recesses is... 1 The number of recesses M is 20-100, with an area of ​​25mm × 25mm arbitrarily chosen on the first surface. 1 A fixed measurement area of ​​25mm × 25mm can be calibrated using vernier calipers. The number of depressions within this area can then be counted manually or using image analysis software (such as ImageJ). To avoid uneven distribution of depressions, measurements can be repeated 3-5 times in different areas of the positive electrode, and the average value can be taken as the final M. 1 This value ensures the accuracy of the statistical count of the number of concave areas.

[0028] In some instances, the number M of organic particles with a surface area of ​​25 μm × 19 μm and a particle size greater than 3.4 μm is optionally present in the diaphragm. 2 The number of particles can range from 2 to 15, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15. The area of ​​the membrane surface, optionally 25 μm × 19 μm, refers to the region of the membrane surface in a 5K magnification SEM image with an area optionally 25 μm × 19 μm, containing the number M of organic particles larger than 3.4 μm. 2The number of organic particles larger than 3.4 μm can be counted using image analysis software (such as ImageJ). To avoid uneven distribution of organic particles, the measurement can be repeated 3-5 times in different areas of the diaphragm, and the average value is taken as the final M. 2 This ensures the accuracy of the statistical count of recesses. Further controlling the number of organic particles larger than 3.4 μm within a certain area is beneficial for improving the uniformity, density, and smoothness of the organic coating. On one hand, it ensures that the chemical function of the organic coating works uniformly and consistently inside the battery, which helps reduce the interfacial resistance between the separator and the electrode. On the other hand, it prevents large-diameter organic particles from breaking during battery cycle expansion, improving interfacial stability and reducing the risk of separator puncture, thus further enhancing battery safety.

[0029] In some instances, the first compound comprises one or more of the following structures: (I-1) (I-2) (I-3) (I-4) (I-5) (I-6) (I-7) (I-8) (I-9) (I-10) (I-11) (I-12) (I-13) (II-1) (II-2) (III-1) (IV-1) (V-1) (VI-1) (VI-2).

[0030] In some instances, the first compound comprises one or more of the following: lithium 2-thiolbenzimidazole, sodium 2-thiolbenzimidazole, potassium 2-thiolbenzimidazole, calcium 2-thiolbenzimidazole, magnesium 2-thiolbenzimidazole, aluminum 2-thiolbenzimidazole, and ammonium 2-thiolbenzimidazole.

[0031] In some instances, the organic coating further includes a first adhesive comprising one or more of polyvinyl alcohol, styrene-butadiene rubber, ethylene-vinyl acetate copolymer, polyvinylpyrrolidone, polyurethane, polyvinylidene fluoride, acrylate adhesives, styrene-acrylic latex, styrene-butadiene rubber, polyacrylonitrile, polyacrylic acid, polyvinyl acetate, polyurethane-modified polyvinylidene fluoride, and polyvinylidene fluoride-hexafluoropropylene.

[0032] In some instances, based on the total weight of the organic coating, the weight percentage of the organic particles is 45%-98%, for example, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98%. Controlling the weight percentage of the organic particles in the organic coating within the above range can further improve the wettability of the separator in the electrolyte, while also ensuring that the organic coating includes sufficient nitrogen-containing fused heterocycles, thereby inhibiting the dissolution and shuttle of the positive electrode transition metal, stabilizing the positive electrode-electrolyte interface; at the same time, it can efficiently capture harmful free radicals generated by electrolyte decomposition, significantly improving the capacity retention and voltage stability of the battery during high-temperature cycling.

[0033] In some examples, the acrylate adhesive includes one or more of the following: polymethyl methacrylate, polybutyl acrylate, acrylate monomer-acrylonitrile copolymer, acrylate monomer-ethylene copolymer, acrylate monomer-acrylonitrile-ethylene copolymer, styrene-acrylate monomer-acrylonitrile copolymer, ethylhexyl acrylate-methyl methacrylate copolymer, butyl acrylate-methyl methacrylate copolymer, methyl acrylate-N,N-dimethylacrylamide copolymer, ethyl acrylate-2-(diethylamino)ethyl acrylate copolymer, ethyl acrylate-N,N-diethylacrylamide copolymer, and ethyl acrylate-2-(diethylamino)ethyl acrylate.

[0034] In some instances, the acrylate monomers are selected from one or more of methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, and ethyl methacrylate.

[0035] In some instances, based on the total weight of the organic coating, the organic particles constitute 90%-98% by weight, for example, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 98%, and the first binder constitutes 2%-10% by weight, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. In the above embodiments, the organic coating may consist of the organic particles and the first binder.

[0036] In this invention, the organic coating can be prepared by the following method: mixing organic particulate raw materials and a first binder in a solvent (e.g., water), stirring thoroughly to form an organic coating slurry, and then coating the organic coating slurry onto a carrier to form an organic coating.

[0037] In some instances, the organic coating further includes filler particles, wherein the organic particles constitute 45%-98% of the total weight of the organic coating, for example, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 98% of the weight; the first binder constitutes 1%-10% of the weight, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10% of the weight; and the filler particles constitute 1%-50% of the weight, for example, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% of the weight. In the above embodiments, the organic coating may consist of the organic particles, the filler particles, and the first binder.

[0038] In this invention, the organic coating can be prepared by the following method: mixing organic particulate raw materials, filler particles and a first binder in a solvent (e.g., water), stirring thoroughly to form an organic coating slurry, and then coating the organic coating slurry onto a substrate layer to form an organic coating.

[0039] In some instances, the filler particles comprise boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, zirconium titanate, barium titanate, magnesium fluoride, poly(p-phenylene terephthalamide), poly(m-phenylene isophthalamide), phenolic resin, modified phenolic resin, 1,3,5-triazine-2,4,6-triamine, melamine thiocyanate, melamine cyanurate, symmetrical triaminotriazine, 2-(4-bromophenyl)- One or more of the following: 4,6-dimethyl-1,3,5-triazine, 1-(4,6-diamino-1,3,5-triazine-2-yl)guanidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, cyanuric chloride, 2,4,6-tris(2-pyridyl)triazine, 2,4,6-triphenyl-1,3,5-triazine, tris(tribromophenoxy)triazine, 2-amino-4,6-methoxy-1,3,5-triazine, 4-amino-2,6-dihydroxypyrimidine, cytosine, guanine, uracil, and cytosine.

[0040] In some examples, the diaphragm includes a carrier layer and an adhesive layer located on one or both surfaces of the carrier layer. The carrier layer includes a substrate layer and an organic coating located on at least one surface of the substrate layer. The adhesive layer includes a polymer, such as poly(p-phenylene terephthalamide), poly(m-phenylene isophthalamide), polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl fluoride, polyhexafluoropropylene, ethylene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, acrylate polymers, and styrene-butadiene rubber. The substrate layer comprises one or more of rubber, phenolic resin, polyimide, modified phenolic resin, and modified polyimide, wherein the substrate layer comprises polyolefin (such as polyethylene, modified polyethylene, polypropylene, modified polypropylene), polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, polytetrafluoroethylene, polyacrylonitrile, modified polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, poly(p-phenylene terephthalate), poly(m-phenylene isophthalate), or at least one of the above polymer derivatives.

[0041] In some instances, after being placed at 130°C for 1 hour, the thermal shrinkage rate of the diaphragm in the length direction (MD direction, i.e., the diaphragm stretching direction) is less than 10%.

[0042] In some instances, after being placed at 130°C for 1 hour, the thermal shrinkage rate of the diaphragm in the width direction (TD direction, i.e., the stretching direction perpendicular to the diaphragm) is less than 10%.

[0043] After being placed at 130℃ for 1 hour, the thermal shrinkage rate of the separator in both length and width directions is less than 10%, ensuring that the separator maintains its structural integrity in high-temperature environments and preventing short circuits caused by direct contact between the positive and negative electrodes due to shrinkage. Simultaneously, it maintains the pore morphology of the separator, preventing blockage of ion transport channels. Combined with the heat dissipation and electrolyte storage function of the positive electrode recess and the interface protection layer of organic particles, it prevents impedance surges caused by interface failure at high temperatures. The specific testing method is as follows: The separator is removed from the battery cell. Separators located at the head, tail, or superanode region of the cell are selected, where the separator is not bonded to the electrode, resulting in a separator with an organic coating. The separator is cleaned with anhydrous ethanol to remove electrolyte and residual lithium salts. It is then placed in a 40℃ vacuum oven to dry and remove solvent. The separator is cut to a suitable size to obtain the test sample, and then baked in a forced-air drying oven at 130℃ for 1 hour. After removal, the dimensional changes of the separator in both the width and length directions after shrinkage are measured to obtain the separator shrinkage rate.

[0044] In some instances, the diaphragm has a permeability value of 50 s / cc to 400 s / cc, for example, 50 s / cc, 60 s / cc, 70 s / cc, 80 s / cc, 90 s / cc, 100 s / cc, 110 s / cc, 120 s / cc, 130 s / cc, 140 s / cc, 150 s / cc, 160 s / cc, 170 s / cc, 180 s / cc, 190 s / cc, 200 s / cc, 2 10s / cc, 220s / cc, 230s / cc, 240s / cc, 250s / cc, 260s / cc, 270s / cc, 280s / cc, 290s / cc, 300s / cc, 310s / cc, 320s / cc, 330s / cc, 340s / cc, 350s / cc, 360s / cc, 370s / cc, 380s / cc, 390s / cc or 400s / cc.

[0045] The membrane's air permeability, ranging from 50-400 s / cc, balances ion transport efficiency and protection. It avoids the short-circuit risk of excessively low permeability while preventing excessively high permeability from hindering ion migration and increasing impedance. This improves electrolyte wettability and ion diffusion, working synergistically with the protective layer formed by organic particles to ensure smooth ion transport while suppressing side reactions, thus enhancing the battery's high-temperature cycle stability and safety. The specific testing method is as follows: Following the definition of air permeability in GB / T36363-2018, air permeability is defined as the area through which 100 mL of air passes under normal temperature, humidity, and pressure conditions, with the testing instrument applying a pressure of 1.21 kPa, and the area being 6.45 cm². 2 The time required for the diaphragm to rupture. The applied pressure of 1.21 kPa is constant, and the distance traveled is 6.45 cm. 2 The area is a fixed area.

[0046] In some examples, the acrylate polymers include one or more of polymethyl methacrylate, polybutyl acrylate, acrylate monomer-acrylonitrile copolymers, acrylate monomer-ethylene copolymers, acrylate monomer-acrylonitrile-ethylene copolymers, styrene-acrylate monomer-acrylonitrile copolymers, ethylhexyl acrylate-methyl methacrylate copolymers, butyl acrylate-methyl methacrylate copolymers, methyl acrylate-N,N-dimethylacrylamide copolymers, ethyl acrylate-2-(diethylamino)ethyl acrylate copolymers, ethyl acrylate-N,N-diethylacrylamide copolymers, and ethyl acrylate-2-(diethylamino)ethyl acrylate. In some preferred examples, the acrylate monomers are selected from one or more of methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, and ethyl methacrylate.

[0047] In some instances, the modified polyamide includes furanyl-modified polyamide, which is a polymer containing a five-membered furan ring and an amide group.

[0048] In some preferred embodiments, the structure of the furanyl-modified polyamide is shown in formula (VII). Equation (VII), where m is an integer from 5 to 100, n is an integer from 5 to 100, and Ar1 is selected from... , Ar2 is selected from one or more of the following groups: , , , , , , , , , , , , , , , , .

[0049] When an adhesive layer is included, the bonding strength between the separator and the electrode can be further improved, and the interfacial impedance can be further reduced. In particular, when the adhesive layer contains furanyl-modified polyamide, the large number of polar functional groups in furanyl-modified polyamide can further improve the electrolyte wetting ability of the separator-electrode interface and further reduce the interfacial impedance.

[0050] In some instances, the organic coating is located on the surface of one side of the substrate layer, with the positive electrode corresponding to the side of the separator where the organic coating is present.

[0051] In some instances, the positive electrode sheet includes a positive current collector and a positive active layer located on one or both sides of the surface of the positive current collector. The positive active layer includes a positive active material with a Dv50 of 3μm-25μm, for example, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, or 25μm.

[0052] The present invention does not impose any particular limitation on the positive electrode active material, and conventional positive electrode active materials in the art can be used. For example, the positive electrode active material may include one or more of lithium nickel oxide, lithium titanate, lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide.

[0053] In some instances, the positive electrode active material comprises a core and a coating layer, the coating layer covering the outer surface of the core, the core comprising lithium cobalt oxide, and the coating layer comprising materials with the chemical formula Li7La. 3-a Zr 2-b Q 1 a+b O 12 The substance, in which Q 1 It is one or more of Fe, Ti, Cu, and Mn, with 0.01≤a≤0.5 (e.g., 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, or 0.5) and 0.05≤b≤0.3 (e.g., 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3).

[0054] In some preferred embodiments, the thickness of the coating layer is 0.1nm-40nm, for example, 0.1nm, 0.5nm, 1nm, 2nm, 3nm, 4nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm or 40nm.

[0055] In some instances, the lithium cobalt oxide material includes doping elements, which include one or more of Al, Mg, Ti, Zr, La, and Y.

[0056] In some instances, the weight percentage of Al is 3ppm-12000ppm based on the total weight of the lithium cobalt oxide material, for example, 3ppm, 10ppm, 50ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm, 1000ppm, 2000ppm, 3000ppm, 4000ppm, 5000ppm, 6000ppm, 7000ppm, 8000ppm, 9000ppm, 10000ppm, 11000ppm, or 12000ppm.

[0057] In some instances, the weight percentage of Mg is 200ppm-1600ppm based on the total weight of the lithium cobalt oxide material, for example, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 1000ppm, 1100ppm, 1200ppm, 1300ppm, 1400ppm, 1500ppm or 1600ppm.

[0058] In some instances, the weight percentage of Ti is 100ppm-1600ppm based on the total weight of the lithium cobalt oxide material, for example, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 1000ppm, 1100ppm, 1200ppm, 1300ppm, 1400ppm, 1500ppm or 1600ppm.

[0059] In some instances, the weight percentage of Ti is 100ppm-1600ppm based on the total weight of the lithium cobalt oxide material, for example, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 1000ppm, 1100ppm, 1200ppm, 1300ppm, 1400ppm, 1500ppm or 1600ppm.

[0060] In some instances, the weight percentage of Zr is 40ppm-500ppm based on the total weight of the lithium cobalt oxide material, for example, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm, 200ppm, 300ppm, 400ppm or 500ppm.

[0061] In some instances, the weight percentage of Y is 100ppm-1000ppm based on the total weight of the lithium cobalt oxide material, for example, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm or 1000ppm.

[0062] In some instances, the weight percentage of La is 100ppm-1000ppm based on the total weight of the lithium cobalt oxide material, for example, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm or 1000ppm.

[0063] In some instances, the positive electrode active layer further includes a positive electrode conductive agent and a positive electrode binder, wherein the positive electrode conductive agent may include one or more of conductive carbon black, carbon nanotubes, conductive graphite and graphene; the positive electrode binder may include one or more of polyvinylidene fluoride (PVDF), acrylic acid-modified PVDF, polyacrylate polymers, acrylic polymers, polytetrafluoroethylene, polyacrylonitrile, polyimide, styrene-butadiene rubber and styrene-acrylic rubber.

[0064] In some instances, the negative electrode sheet includes a negative current collector and a negative active layer located on one or both sides of the negative current collector. The negative active layer includes a negative active material, which includes one or more of elemental silicon particles, silicon-oxygen particles, silicon-carbon particles, silicon-nitrogen particles, and silicon alloy particles.

[0065] In some instances, the average particle size of the silicon-carbon particles is 6 μm-10 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm.

[0066] In some instances, the negative electrode active layer further includes a negative electrode conductive agent and a negative electrode binder.

[0067] In some instances, the negative electrode conductive agent includes one or more of furnace black, acetylene black, Ketjen black, and carbon nanotubes.

[0068] In some instances, the negative electrode binder includes one or more of polyurethane, acrylic-acrylonitrile copolymer, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyacrylic acid (PAA), carboxymethyl cellulose (CMC), and styrene-butadiene rubber (SBR).

[0069] In this invention, the battery further includes an electrolyte.

[0070] In some instances, the electrolyte includes lithium salts, solvents, and additives, with the solvents including polar solvents.

[0071] In some instances, the electrolyte includes a polar solvent selected from at least one of 2,2-difluoroethyl acetate, ethyl 2,2-difluoroacetate, propyl propionate, ethyl propionate, diethyl carbonate, propylene carbonate, and ethylene carbonate.

[0072] In some instances, the lithium salt includes at least one of lithium hexafluorophosphate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium difluorophosphate, lithium tetrafluoroborate, lithium di(oxalate)borate, lithium di(fluorooxalate)borate, and lithium di(fluorobis(oxalate))phosphate.

[0073] In some instances, the additives can be selected based on battery performance requirements and in conjunction with industry-standard technologies.

[0074] In some instances, the solvent may also include organic solvents other than the aforementioned polar solvents.

[0075] In some instances, the lithium salt accounts for 5%-35% of the total weight of the electrolyte (e.g., 5%, 10%, 15%, 20%, 25%, 30%, or 35%), the solvent accounts for 30%-80% of the total weight of the electrolyte (e.g., 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, or 80%), and the additives account for 3%-35% of the total weight of the electrolyte (e.g., 3%, 5%, 10%, 15%, 20%, 25%, 30%, or 35%).

[0076] In some instances, the lithium-ion battery is a lithium-ion rechargeable battery.

[0077] The present invention will be described in detail below through embodiments. The embodiments described herein are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0078] Example 1 (1) Preparation of positive electrode Lithium cobalt oxide, polyvinylidene fluoride (PVDF 500) binder, and conductive material (SuperP: carbon nanotubes = 2:1) were mixed in N-methylpyrrolidone (NMP) solvent at a weight ratio of 98:2:2 and continuously stirred under the action of a stirrer to form a homogeneous and fluid positive electrode slurry. Subsequently, the positive electrode slurry was coated onto an aluminum foil with a thickness of 10 μm and dried in a vacuum oven at 120°C for 6 hours. Then, it was rolled, slit, and pressed to form concave portions to obtain the desired positive electrode sheet. The first surface of the positive electrode sheet has concave portions, and the second surface has convex portions, with the convex portions facing the concave portions.

[0079] (2) Preparation of negative electrode sheet Graphite, silicon carbide (average particle size = 9 μm), conductive material (carbon black: carbon nanotubes = 1:4), sodium carboxymethyl cellulose, and binder (styrene-butadiene rubber: polyacrylic acid = 1:2) were mixed in an aqueous solvent at a weight ratio of 30:65:3.5:1:0.5 and continuously stirred under the action of a stirrer to form a homogeneous and fluid negative electrode slurry. Subsequently, the slurry was coated on the surface of a current collector copper foil with a thickness of 8 μm and dried in a vacuum oven at 120℃ for 6 hours. Then, after rolling and slitting, the desired negative electrode sheet was obtained.

[0080] (3) Electrolyte preparation In an argon-filled glove box (moisture content <1 ppm, oxygen content <1 ppm), ethylene carbonate (EC), propylene carbonate (PC), propyl propionate (PP), and ethyl propionate (EP) solvents were mixed in a volume ratio of 1:5:5:10 to form a homogeneous solvent. Then, 15 wt% LiPF6, 1.5 wt% succinate, 1.5 wt% 1,4-dicyano-2-butene, and 12.5 wt% fluoroethylene carbonate were slowly added and stirred until homogeneous to obtain the desired lithium-ion battery electrolyte.

[0081] (4) Preparation of the diaphragm The organic particles 2-mercaptobenzimidazole (the first compound shown in formula (I-1)) (D 1 The mixture (Dv10 is 0.26 μm) and polyacrylic acid were mixed and thoroughly stirred to obtain a mixed slurry with a solid content of 20%. The slurry was applied to a substrate using a 100% solids mass ratio of organic particles (2-mercaptobenzimidazole) to acrylate adhesive (polyacrylic acid) of 96:4. After drying in a multi-section oven at 60°C, a heat-resistant coating with a thickness of 2 μm was formed. SEM images of the organic coating were obtained using a scanning electron microscope. Figure 1 As shown, vinylidene fluoride-hexafluoropropylene copolymer and alumina are dispersed in solvent N,N-dimethylacetamide (DMAC). After thorough stirring, a slurry with a solid content of 10% is obtained. The mixed slurry is coated on both sides of the above-mentioned diaphragm by gravure rollers. After water tank extraction and drying in a multi-section oven at 60°C, an adhesive layer is formed.

[0082] (5) Preparation of lithium-ion batteries The above-prepared positive electrode sheet, separator, and negative electrode sheet are wound together to form a bare cell. The bare cell is then placed in an aluminum-plastic film, and the prepared electrolyte is injected into the dried bare cell. After vacuum sealing, room temperature standing, and high temperature formation, the desired lithium-ion battery is obtained.

[0083] The depth D of the concave region was obtained through SEM testing. 2 The diameter of the recess is 18 μm, the width of the recess is 2 mm, the morphology of the recess is a hole, and the area of ​​the first surface is optionally 25 mm × 25 mm. The number of recesses M is... 1 There are 39; The number M of organic particles with a particle size greater than 3.4 μm and an area of ​​25 μm × 19 μm on the surface of the membrane was obtained by SEM testing. 2 There are 8, M 1 / M 2=4.88; After the diaphragm is placed at 130℃ for 1 hour, the thermal shrinkage rate of the diaphragm in the length direction is 5.3%, and after the diaphragm is placed at 130℃ for 1 hour, the thermal shrinkage rate of the diaphragm in the width direction is 5.3%; The air permeability of the diaphragm is 157s / cc.

[0084] Example 2 group This set of examples illustrates the effects that occur when the specific choice of the first compound changes.

[0085] This set of examples is based on Example 1, except that the specific selection of the first compound is changed, as detailed in Table 1-1.

[0086] Table 1-1 Example 3 Group This set of examples is used to illustrate when D 2 / D 1 The effects of changes.

[0087] This embodiment group is carried out with reference to Embodiment 1, except that D is changed. 2 / D 1 See Table 1-2 for details.

[0088] Comparative Example 1 This set of comparative examples is used to illustrate when D... 2 / D 1 The impact of changes.

[0089] This comparative example group was conducted in accordance with Example 1, except that D was changed. 2 / D 1 See Table 1-2 for details.

[0090] Table 1-2 Example 4 group This set of examples is used to illustrate when M 1 / M 2 The effects of changes.

[0091] This embodiment is based on Embodiment 1, except that M is changed. 1 / M 2 For details, please refer to Table 1-3.

[0092] Table 1-3 Example 5 group This set of examples illustrates the effects of changes in the weight percentage of organic particles in an organic coating.

[0093] This embodiment group is based on Embodiment 1, except that the weight ratio of organic particles in the organic coating is changed, as detailed in Tables 1-4.

[0094] Example 6 group This set of examples illustrates the effects that occur when the width of the recess changes.

[0095] This embodiment group is based on Embodiment 1, except that the width of the recess is changed, as detailed in Tables 1-4.

[0096] Table 1-4 Comparative Example 2 The procedure was carried out in accordance with Example 1, except that the organic particles were replaced with the same amount of alumina particles by weight.

[0097] Comparative Example 3 The procedure was carried out in accordance with Example 1, except that the organic particles were replaced with 2-mercaptoimidazole and tetramercaptobenzene, wherein the structural formula of 2-mercaptoimidazole is as follows: The structural formula of tetramercaptobenzene is Furthermore, the organic particles do not contain nitrogen-containing fused heterocycles.

[0098] Test case The lithium-ion batteries prepared in the above embodiments and comparative examples were subjected to the following tests.

[0099] (1) High-temperature cycling voltage drop and high-temperature cycling impedance change rate test: At 45℃±2℃, the circuit was left to stand for 20 minutes, then charged at 0.5C constant current and constant voltage to 4.53V, cut off at 0.05C, and left to stand for 10 minutes. The voltage V1 before cycling was measured and recorded. The initial fully charged impedance R1 was measured using an electrochemical workstation. Then, the circuit was discharged at 0.2C constant current to 3.0V and left to stand for 10 minutes. The circuit was then cycled for 550T as follows: charged at 0.5C to 4.53V, then charged at constant voltage to the cutoff current of 0.05C, left to stand for 5 minutes, and then discharged at 0.7C constant current to 3.0V. After cycling, the circuit was charged at 0.5C to 4.53V, then charged at constant voltage to the cutoff current of 0.05C, left to stand for 10 minutes, and the voltage V2 after cycling was measured and recorded. The fully charged impedance R2 after cycling was measured using an electrochemical workstation. The impedance change rate is calculated as [(R2-R1) / R1]×100%, in units of %; the voltage drop is calculated as V1-V2, in units of V (volts).

[0100] (2) Furnace temperature test A fully charged lithium-ion secondary battery cell was placed in a test chamber and heated to 135°C at a heating rate of 5°C / min, and held at that temperature for 60 minutes. The battery status was recorded. Twenty battery samples were tested for each example and comparative example. If the battery did not explode and / or catch fire, it was considered a "pass". If it exploded or caught fire, it was considered a "fail". The result was expressed as "number of passes / 20pcs". For example, "20 / 20pcs" means all passed, and "10 / 20pcs" means 10 out of 20 batteries passed.

[0101] The results are recorded in Table 2.

[0102] Table 2 As can be seen from Table 2, by comparing the comparative example and the embodiment, the high-temperature cycling voltage drop and cycling impedance change rate of the battery in the embodiment are significantly reduced, and the furnace temperature test pass rate is significantly improved. This indicates that through the synergistic effect of the organic coating of the separator and the concave structure of the positive electrode, the high-temperature safety performance of the battery can be significantly improved without sacrificing the voltage stability and impedance during high-temperature cycling, and the furnace temperature tolerance of the battery can be improved, thereby meeting the increasingly stringent high-temperature application requirements.

[0103] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A battery, characterized in that, The battery includes a positive electrode, a negative electrode, and a separator, with the separator located between the positive and negative electrode. In the thickness direction of the positive electrode, the positive electrode includes a first surface and a second surface facing away from each other. The first surface includes a plurality of recesses, the depth of which is D. 2 The range is 3μm-50μm; The membrane includes a substrate layer and an organic coating located on at least one surface of the substrate layer. The organic coating includes organic particles, and the organic particles include a first compound whose molecular structure includes a nitrogen-containing fused heterocycle, the nitrogen-containing fused heterocycle being selected from one or more of the following structures: (I)、 (II)、 (III)、 (IV)、 (V)、 (VI)? The battery satisfies the following relationship: 4.4 ≤ D 2 / D 1 ≤950, where D 1 Dv10 of the organic particles, in μm. 2 The depth of the concave portion is expressed in μm.

2. The battery according to claim 1, wherein, The Dv10 of the organic particles is 0.05 μm-0.9 μm; And / or, the width of the recess is 1mm-5mm; And / or, the morphology of the recess includes one or more of holes, lines, and grooves; And / or, the battery satisfies the following relationship: 1.5 ≤ M 1 / M 2 ≤80, preferably 3≤M 1 / M 2 ≤40, where M 1 The first surface is optionally 25m m The number of recesses with an area of ​​×25mm, in units of M. 2 The number of organic particles with a surface area of ​​25 μm × 19 μm and a particle size greater than 3.4 μm on the membrane, expressed in units of individual particles; And / or, the first surface is optionally 25m m ×25m m The area of ​​the recesses and the number of recesses M 1 The number ranges from 15 to 165, with 20 to 100 being preferred; And / or, the number M of organic particles with a surface area of ​​25 μm × 19 μm and a particle size greater than 3.4 μm on the membrane. 2 The number ranges from 2 to 15.

3. The battery according to claim 1, wherein, The first compound comprises one or more of the following structures: (I-1) (I-2) (I-3) (I-4) (I-5) (I-6) (I-7) (I-8) (I-9) (I-10) (I-11) (I-12) (I-13) (II-1) (II-2) (III-1) (IV-1) (V-1) (VI-1) (VI-2); And / or, the first compound comprises one or more of the following: lithium 2-thiolbenzimidazole, sodium 2-thiolbenzimidazole, potassium 2-thiolbenzimidazole, calcium 2-thiolbenzimidazole, magnesium 2-thiolbenzimidazole, aluminum 2-thiolbenzimidazole, and ammonium 2-thiolbenzimidazole.

4. The battery according to any one of claims 1-3, wherein, The organic coating further includes a first adhesive, which includes one or more of the following: polyvinyl alcohol, styrene-butadiene rubber, ethylene-vinyl acetate copolymer, polyvinylpyrrolidone, polyurethane, polyvinylidene fluoride, acrylate adhesives, styrene-acrylic latex, styrene-butadiene rubber, polyacrylonitrile, polyacrylic acid, polyvinyl acetate, polyurethane-modified polyvinylidene fluoride, and polyvinylidene fluoride-hexafluoropropylene. Preferably, based on the total weight of the organic coating, the organic particles account for 45%-98% of the total weight. Preferably, the acrylate adhesive comprises one or more of the following: polymethyl methacrylate, polybutyl acrylate, acrylate monomer-acrylonitrile copolymer, acrylate monomer-ethylene copolymer, acrylate monomer-acrylonitrile-ethylene copolymer, styrene-acrylate monomer-acrylonitrile copolymer, ethylhexyl acrylate-methyl methacrylate copolymer, butyl acrylate-methyl methacrylate copolymer, methyl acrylate-N,N-dimethylacrylamide copolymer, ethyl acrylate-2-(diethylamino)ethyl acrylate copolymer, ethyl acrylate-N,N-diethylacrylamide copolymer, and ethyl acrylate-2-(diethylamino)ethyl acrylate.

5. The battery according to claim 4, wherein, Based on the total weight of the organic coating, the organic particles account for 90%-98% of the weight, and the first binder accounts for 2%-10% of the weight. And / or, the acrylate monomers are selected from one or more of methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, and ethyl methacrylate.

6. The battery according to claim 4, wherein, The organic coating also includes filler particles, wherein, based on the total weight of the organic coating, the organic particles account for 45%-98% of the weight, the first binder accounts for 1%-10% of the weight, and the filler particles account for 1%-50% of the weight. And / or, the acrylate monomers are selected from one or more of methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate and ethyl methacrylate; Preferably, the filler particles comprise boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon dioxide, tin dioxide, titanium dioxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, cerium oxide, zirconium titanate, barium titanate, magnesium fluoride, poly(p-phenylene terephthalamide), poly(m-phenylene isophthalamide), phenolic resin, modified phenolic resin, 1,3,5-triazine-2,4,6-triamine, melamine thiocyanate, melamine cyanurate, symmetrical triaminotriazine, and 2-(4-bromophenyl)-4 One or more of the following: 6-dimethyl-1,3,5-triazine, 1-(4,6-diamino-1,3,5-triazine-2-yl)guanidine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, cyanuric chloride, 2,4,6-tris(2-pyridyl)triazine, 2,4,6-triphenyl-1,3,5-triazine, tris(tribromophenoxy)triazine, 2-amino-4,6-methoxy-1,3,5-triazine, 4-amino-2,6-dihydroxypyrimidine, cytosine, guanine, uracil, and cytosine.

7. The battery according to any one of claims 1-3, wherein, 10≤D 2 / D 1 ≤600; And / or, the diaphragm includes a carrier layer and an adhesive layer located on one or both surfaces of the carrier layer, the carrier layer including a substrate layer and an organic coating located on at least one surface of the substrate layer, the adhesive layer including a polymer, the polymer including one or more of poly(p-phenylene terephthalamide), poly(m-phenylene isophthalamide), polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl fluoride, polyhexafluoropropylene, ethylene fluoride-hexafluoropropylene copolymer, ethylene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, acrylate polymers, styrene-butadiene rubber, phenolic resin, modified polyamide, polyimide, modified phenolic resin, and modified polyimide; And / or, after being placed at 130°C for 1 hour, the thermal shrinkage rate of the diaphragm in the length direction is less than 10%, and / or, after being placed at 130°C for 1 hour, the thermal shrinkage rate of the diaphragm in the width direction is less than 10%; And / or, the air permeability of the diaphragm is 50s / cc-400s / cc.

8. The battery according to claim 7, wherein, The acrylate polymers include one or more of polymethyl methacrylate, polybutyl acrylate, acrylate monomer-acrylonitrile copolymers, acrylate monomer-ethylene copolymers, acrylate monomer-acrylonitrile-ethylene copolymers, styrene-acrylate monomer-acrylonitrile copolymers, ethylhexyl acrylate-methyl methacrylate copolymers, butyl acrylate-methyl methacrylate copolymers, methyl acrylate-N,N-dimethylacrylamide copolymers, ethyl acrylate-2-(diethylamino)ethyl acrylate copolymers, ethyl acrylate-N,N-diethylacrylamide copolymers, and ethyl acrylate-2-(diethylamino)ethyl acrylate. Preferably, the acrylate monomers are selected from one or more of methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, and ethyl methacrylate. And / or, the modified polyamide includes furanyl-modified polyamide, which is a polymer containing a five-membered furan ring and an amide group. Preferably, the structure of the furanyl-modified polyamide is shown in formula (VII). Equation (VII), where m is an integer from 5 to 100, n is an integer from 5 to 100, and Ar1 is selected from... , Ar2 is selected from one or more of the following groups: , , , , , , , , , , , , , , , , .

9. The battery according to any one of claims 1-3, wherein, The organic coating is located on one side of the substrate layer, and the positive electrode sheet corresponds to the side of the separator where the organic coating exists; And / or, the positive electrode sheet includes a positive current collector and a positive active layer located on one or both surfaces of the positive current collector. The positive active layer includes a positive active material with a Dv50 of 3μm-25μm. Preferably, the positive active material includes a core and a coating layer, the coating layer covering the outer surface of the core. The core includes lithium cobalt oxide material, and the coating layer includes materials with the chemical formula Li7La. 3-a Zr 2-b Q 1 a+b O 12 The substance, in which Q 1 The coating is one or more of Fe, Ti, Cu, and Mn, with 0.01≤a≤0.5 and 0.05≤b≤0.

3. More preferably, the thickness of the coating layer is 0.1nm-40nm. And / or, the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer located on one or both sides of the negative electrode current collector. The negative electrode active layer includes a negative electrode active material, which includes one or more of elemental silicon particles, silicon-oxygen particles, silicon-carbon particles, silicon-nitrogen particles, and silicon alloy particles. Preferably, the average particle size of the silicon-carbon particles is 6μm-10μm.

10. The battery according to claim 9, wherein, The lithium cobalt oxide material includes doping elements, which include one or more of Al, Mg, Ti, Zr, La and Y; Preferably, based on the total weight of the lithium cobalt oxide material, the weight percentage of Al is 3ppm-12000ppm; Preferably, based on the total weight of the lithium cobalt oxide material, the weight percentage of Mg is 200ppm-1600ppm; Preferably, the weight percentage of Ti is 100ppm-1600ppm based on the total weight of the lithium cobalt oxide material; Preferably, the weight percentage of Ti is 100ppm-1600ppm based on the total weight of the lithium cobalt oxide material; Preferably, based on the total weight of the lithium cobalt oxide material, the weight percentage of Zr is 40ppm-500ppm; Preferably, based on the total weight of the lithium cobalt oxide material, the weight percentage of Y is 100ppm-1000ppm; Preferably, the weight percentage of La is 100ppm-1000ppm based on the total weight of the lithium cobalt oxide material.

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