Separator, method for manufacturing the same, secondary battery, battery module, battery pack, and power consumption device

Abstract

The present application provides a separator, a manufacturing method thereof, and a secondary battery, a battery module, a battery pack, and a power consumption device including the separator, wherein the separator includes a substrate and a coating applied to at least one surface of the substrate, the coating includes 40-90 wt% of first organic particles, 2-15 wt% of a pressure-sensitive adhesive, and optionally 0-50 wt% of second organic particles, wherein the first organic particles include an organic polymer and an inorganic material, and the pressure-sensitive adhesive includes an organic polymer and a plasticizer. The separator according to the present application has good ion conduction ability and adhesion performance at room temperature, and does not adhere under the action of a pressure of ≦1 MPa, but obviously adheres under the action of a pressure of ≧2 MPa, which can obviously improve the structural stability and ion conduction of electrochemical devices, and at the same time, can balance the manufacturing yield and dynamic performance requirements of battery cores.

Description

[Technical Field]

[0001] This application relates to the battery technology field, and more particularly to separators, methods for manufacturing the same, and secondary batteries, battery modules, battery packs, and power consumption devices including the separator. [Background technology]

[0002] In the manufacturing process of electrochemical device battery cores, misalignment of the electrode plates and separators is unavoidable during transport. In mild cases, this can cause the electrode plates to wrinkle after full charge, seriously affecting dynamic performance and reducing the safety performance of the battery core. In severe cases, the electrode plates may come into contact with each other, rendering the dry cell battery core unusable. Therefore, engineers apply an adhesive coating to the separators and, generally, pre-pressure with appropriate pressure during the first compounding process of the electrochemical device's electrode plates and separators to ensure a certain level of adhesion before the electrode plates and separators proceed to the next process. However, due to production efficiency requirements, the pressure and application time in the first process are often insufficient to achieve proper adhesion between the electrochemical device's electrode plates and separators. On the other hand, proper adhesion is also required between separators during transport. If the adhesive force is too strong, it can cause the separator layers to stick together, which is detrimental to the subsequent high-speed compounding of the electrode plates and separators. Therefore, how to ensure proper adhesion between the separator and the electrode plate to improve safety performance, and how to prevent excessive adhesion between separators during transportation that could affect subsequent use of the separators, are urgent issues that require the engineers to resolve quickly.

[0003] In addition to resolving the above issues, it is also necessary to consider whether excessively high surface density of the adhesive material degrades the separator's resistance, whether the adhesive strength of the material is appropriate at high and low temperatures, and whether blocking the separator's holes increases its resistance and further affects the dynamic performance of the battery core.

[0004] As can be understood from this, it is very meaningful to develop a separator that can solve the above problems simultaneously.

Summary of the Invention

[0005] The present invention has been made in view of the above problems, and its object is to provide a separator, a method for manufacturing the same, a secondary battery, a battery module, a battery pack, and a power consumption device including the separator.

[0006] To achieve the above object, the first aspect of the present application provides a separator, which includes a substrate, and a coating applied to at least one surface of the substrate, where the coating includes 40-90 wt% of first organic particles, 2-15 wt% of a pressure-sensitive adhesive, and optionally 0-50 wt% of second organic particles, the first organic particles include an organic polymer and an inorganic substance, and the pressure-sensitive adhesive includes an organic polymer and a plasticizer, optionally, the volume average particle size of the first organic particles satisfies (Dv90-Dv10) / Dv50≦2.5, optionally ≦2, and further optionally ≦1.8, and the glass transition temperature of the first organic particles is 20-100°C, optionally 30-80°C, optionally, the separator satisfies 0.1 g·m -2 ·Ω -1 ≦ρ / R≦1.0 g·m -2 ·Ω -1 optionally 0.5 g·m -2 ·Ω -1 ≦ρ / R≦0.9 g·m -2 ·Ω -1 further optionally 0.6 g·m -2 ·Ω -1 ≦ρ / R≦0.8 g·m -2 ·Ω -1 where ρ represents the surface density of the coating on the substrate, and R represents the resistance of the separator at 25°C.

[0007] This separator contains a pressure-sensitive adhesive and has good pressure-sensitive properties, with an adhesive strength of 0.08 N / m or less at ≤1 MPa, thus preventing adhesion between separators during winding and storage. At the same time, a clear adhesive action can be generated with the electrode plate at room temperature (generally 20-30°C, e.g., 25°C) and a pressure of ≥2 MPa, so when manufacturing battery cores using this separator, the electrode plate and separator can be tightly bonded at room temperature and appropriate pressure. Selectively, the separator is 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 The separator satisfies these conditions, thereby providing excellent adhesive performance while simultaneously preventing deterioration of dynamic performance due to increased separator resistance.

[0008] In each embodiment, the first organic particle is selectively, (1) The volume-average particle size Dv50 of the first organic particle is 3-36 μm, and selectively 5-20 μm. (2) The vitrification transfer temperature of the first organic particles is 20-100°C, selectively 30-80°C. (3) The weight-average molecular weight of the organic polymer in the first organic particle is 500 × 10 3 g / mol - 1000 × 10 3 g / mol, selectively 800 × 10 3 g / mol - 1000 × 10 3 It satisfies one or more of the following conditions: it is g / mol.

[0009] In each embodiment, the organic polymer in the first organic particle is selectively at least A first polymerizable monomer having at least one ester bond and selectively being one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, vinyl acetate, trifluoroethyl methacrylate, glycidyl methacrylate, or trimethylolpropane triacrylate, and further selectively being one or more of methyl methacrylate, lauryl acrylate, lauryl methacrylate, or trimethylolpropane triacrylate, A second polymerizable monomer having at least one cyanide bond, selectively being one or more of acrylonitrile, methacrylonitrile, and ethacrylonitrile, and further selectively being one or more of acrylonitrile and methacrylonitrile, It is polymerized with a monomer having at least one amide bond, which is selectively one or more of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide, and further selectively one or more of acrylamide and N-methylolacrylamide, Selectively, the weight ratios of the first polymerizable monomer, the second polymerizable monomer, and the third polymerizable monomer are 1:0-0.8:0.05-0.75 and selectively 1:0.1-0.6:0.1-0.6.

[0010] When an organic polymer is produced by polymerizing the above polymerizable monomer, the first organic particles produced have good adhesive performance and a relatively low vitrification transfer temperature. Furthermore, the density ρ of the adhesive material on the separator and the resistance R of the separator are 0.1 g·m². -2 ·Ω -1≤ρ / R ≤ 1.0g·m -2 ·Ω -1 By satisfying this condition, the resistance of the separator is reduced, which helps improve the dynamic performance of batteries employing this separator.

[0011] In each embodiment, the content of the organic polymer in the first organic particles is selectively 50-99.9%, selectively 60-99%, and more selectively 70-99%, based on the total dry weight of the first organic particles. The inorganic content in the first organic particles is 0.1-50%, selectively 1-40%, and more selectively 1-30%, based on the total dry weight of the first organic particles.

[0012] In each embodiment, selectively, the weight ratio of the organic polymer to the inorganic material in the first organic particles is 99:1-1:1, and selectively, 70:30-1:1.

[0013] In each embodiment, selectively, based on the total weight of the organic polymer in the first organic particles, The content of the first polymerizable monomer is 35-80% by weight, and selectively 45-70% by weight. The content of the second polymerizable monomer is 0-30% by weight, selectively 5-25% by weight, and The content of the third polymerizable monomer is 5-40% by weight, and selectively 8-35% by weight.

[0014] In any embodiment, the inorganic material in the first organic particle is selectively selected from one or more of silicon, aluminum, calcium, zinc, magnesium oxides and sodium sulfate, sodium benzoate, calcium carbonate and their modifiers, selectively selected from one or more of silicon dioxide, silica sol, aluminum oxide, zinc oxide, magnesium oxide, and sodium benzoate, and further selectively selected from one or more of fumed silicon dioxide, silicon fine powder, aluminum oxide, and sodium benzoate.

[0015] In each embodiment, the surface of the first organic particles is selectively uneven, and inorganic oxide clusters with a particle size of 10-200 nm are uniformly distributed thereon.

[0016] In each embodiment, selectively, the mass ratio of the organic polymer to the plasticizer contained in the pressure-sensitive adhesive is (4-25):1, and selectively, (4-11):1.

[0017] By ensuring that the relative content of organic polymers and plasticizers in the pressure-sensitive adhesive is within the above range, a relatively large adhesive strength is obtained between the electrode plate and the separator, which is advantageous for improving adhesive performance and cycle performance without significantly increasing the resistance of the separator.

[0018] In each embodiment, the pressure-sensitive adhesive selectively has a core-shell structure, where the core and housing of the core-shell structure both contain an organic polymer and a plasticizer, where the mass ratio of the organic polymer to the plasticizer in the core is (3-4):1, selectively (3.2-3.8):1, and the mass ratio of the organic polymer to the plasticizer in the housing structure is (7-9):1, selectively (7.5-8.5):1.

[0019] The core and housing of the core-shell structure are mainly composed of organic polymers and plasticizers, which can further improve the pressure-sensitive performance of the pressure-sensitive adhesive, thereby improving the applicability of the separator to different pressure modes and favorably reducing the resistance of the separator, thereby enhancing the dynamic performance of the separator.

[0020] In each embodiment, selectively, in the pressure-sensitive adhesive, a portion of the plasticizer is grafted onto the organic polymer, and selectively, in the pressure-sensitive adhesive, at least 5 wt% of the plasticizer, based on the weight of the plasticizer, is grafted onto the organic polymer.

[0021] When some of the plasticizer is grafted onto the organic polymer, it is possible to prevent a large amount of the plasticizer from migrating into the electrolyte during the cycle, thereby avoiding the consumption of various functional additives in the electrolyte, and further increasing the resistance of the separator, which would affect the dynamic performance of the battery core.

[0022] In each embodiment, the volume-average particle size Dv50 of the pressure-sensitive adhesive is selectively 0.3-3.5 μm, and selectively 0.8-2.0 μm.

[0023] A pressure-sensitive adhesive with an appropriate particle size helps to be uniformly distributed among the first organic particles or both the first and second organic particles, contributing to the adhesion between the core and housing and the electrode plates at a constant pressure, and to an effective improvement in the kinetic performance of the separator.

[0024] In each embodiment, the vitrification transfer temperature of the pressure-sensitive adhesive is selectively -50°C to 100°C, and selectively -45°C to 60°C.

[0025] If the vitrification transfer temperature of the pressure-sensitive adhesive is within the above range, it is advantageous for ensuring adhesive strength at room temperature, avoiding the problem of the separator sticking together during storage due to an adhesive strength greater than 0.08 N / m at 1 MPa, making it difficult to wind and unwind the separator, and also avoiding the problem of the adhesive strength being less than 0.1 N / m at room temperature and 2 MPa, resulting in weak adhesion between the separator and the electrode plate, which is disadvantageous for shaping the battery core.

[0026] In any embodiment, selectively, the pressure-sensitive adhesive comprises a copolymer obtained by copolymerizing a mixture of at least one of the following first monomer group, at least one of the second monomer group, at least one of the third monomer group, and at least one of the reactive dispersants, i.e., The first group of monomers includes acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylolacrylamide, acrylamide, styrene, and acrylonitrile. The second group of monomers is acrylic acid C4-C 22 Alkyl esters, such as isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate (isoooctyl acrylate), cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, ethyleneurea ethyl methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylic methacrylate, and dicyclopentenyloxyethyl methacrylate, The third group of monomers includes 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, γ-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethacrylamide, diacetoneacrylamide (DAAM), acetate acetate methacrylate (AAEM), divinylbenzene, epoxy resins with an epoxy value of 0.35-0.50, and divinylbenzene. The reactive dispersant includes polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, and polyvinyl alcohol.

[0027] In each embodiment, the degree of alcohol decomposition of the reactive dispersant is selectively ≥ 85%, the number-average degree of polymerization is 400-2000, preferably the degree of alcohol decomposition is ≥ 88%, and the number-average degree of polymerization is 500-1600.

[0028] In each embodiment, the plasticizer is selectively glycerol C4-C 10 Alkyl diether or monoether, glycerol C4-C 10 Carboxylic acid monoester or diester, propylene glycol C4-C 10 Selected from one or more alkyl monoethers or glycerols.

[0029] In each embodiment, the average thickness of the coating is selectively 0.8–22 μm and selectively 2–15 μm.

[0030] In any embodiment, the second organic particle is selectively a polymer of one or more monomers including a halogen, a phenyl group, an epoxy group, a cyano group, an ester group, and an amide group. Selectively, the second organic particle is selected from at least one of the following: homopolymers or copolymers of fluorine-containing alkenyl monomer units, homopolymers or copolymers of olefin-based monomer units, homopolymers or copolymers of unsaturated nitrile-based monomer units, homopolymers or copolymers of alkylene oxide-based monomer units, dipolymers, homopolymers or copolymers of monosaccharide monomer units, and modified compounds of each of the above homopolymers or copolymers.

[0031] In any embodiment, the fluorine-containing alkenyl monomer unit is selectively selected from one or more of difluoroethylene, vinylidene fluoride, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene, or derivatives thereof.

[0032] In each embodiment, the olefin monomer unit is selectively selected from one or more of ethylene, propylene, butadiene, isoprene, styrene, or their derivatives.

[0033] In each embodiment, the unsaturated nitrile monomer unit is selectively selected from one or more of acrylonitrile, methacrylonitrile, or their derivatives.

[0034] In each embodiment, the alkylene oxide monomer unit is selectively selected from one or more of ethylene oxide, propylene oxide, or derivatives thereof.

[0035] In each embodiment, the monosaccharide monomer unit is selectively selected from glucose or its derivatives.

[0036] In any embodiment, the second organic particle is selectively selected from at least one of polyperfluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polystyrene-co-methyl methacrylate, polystyrene-co-butyl acrylate, styrene-butyl acrylate-isooctyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyethylene-co-vinyl acetate, polyimide, polyethylene oxide, cellulose acetate, cellulose butyrate acetate, cellulose propionate acetate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethylcellulose, and cyanoethyl sucrose.

[0037] In any embodiment, the second organic particle is selectively selected from at least one of polyvinylidene fluoride-co-hexafluoropropylene, polystyrene-co-butyl acrylate, styrene-butyl acrylate-isooctyl acrylate, polyperfluoroethylene, polyvinylidene fluoride, and polyvinylidene fluoride-co-trichloroethylene.

[0038] In each embodiment, the second organic particle is selectively, (1) The volume-average particle size Dv50 of the second organic particle is 2-20 μm, and selectively 6-15 μm. (2) The melting point of the second organic particle is 130-160°C, and selectively 138-150°C. (3) The weight-average molecular weight of the second organic particle is 400 × 10 3 g / mol - 1000 × 10 3 g / mol, selectively 450 × 10 3 g / mol - 650 × 10 3 It is g / mol, It satisfies one or more of the following conditions.

[0039] The melting point of the second organic particle is within the above range, allowing it to withstand the swelling of the electrolyte. On the other hand, it does not consume excessive electrolyte, and residual monomers are less likely to bubble up due to the electrolyte, blocking the separator and increasing the resistance of the separator, thereby affecting the dynamic performance of the battery core. On the other hand, the adhesion between the separator and the electrode plate is not significantly reduced, and the electrode plate is less likely to suffer pressure loss due to the second organic particle, thus reducing its safety performance.

[0040] In each embodiment, the separator is selectively provided. (1) The porosity of the substrate is 10-95%. (2) The pore diameter of the substrate is 20-60 nm. (3) The thickness of the substrate is 3-12 μm, and selectively 5-9 μm. (4) The substrate is a film or nonwoven fabric selected from one or more of polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cycloolefin copolymer, polyphenylene sulfide, and polyethylene naphthalene. It satisfies one or more of the following conditions.

[0041] If the separator satisfies one or more of the above conditions, it is advantageous for further improving the adhesive performance of the separator and the kinetic and cyclic performance of the corresponding secondary battery.

[0042] In each embodiment, selectively, in the separator, the mass ratio of the first organic particles to the second organic particles is 10-100:0-90, selectively, 20-90:0-60. Selectively, the ratio of the sum of the masses of the first organic particles and the second organic particles to the mass of the pressure-sensitive adhesive is 20-92:8-20, and selectively 60-90:10-15.

[0043] A second aspect of this application provides a method for manufacturing the separator of the first aspect of this application, which manufacturing method is Step S1 involves adding the first organic particles and a dispersant to the solvent to form the first polymer solution, Step S2 involves adding a pressure-sensitive adhesive to the first polymer solution obtained in step S1 and mixing thoroughly to form a second polymer solution. Optionally, step S3 involves adding a second organic particle to the second polymer solution obtained in step S2 and mixing thoroughly to form a third polymer solution. Step S4 includes applying the second polymer solution obtained in step S2 or the third polymer solution obtained in step S3 to at least one surface of the substrate, drying, and then obtaining a separator. The separator comprises a substrate and a coating applied to at least one surface of the substrate, wherein the coating comprises 40-90 wt% of first organic particles, 2-15 wt% of a pressure-sensitive adhesive, and optionally 0-50 wt% of second organic particles, wherein the first organic particles comprise an organic polymer and an inorganic substance, and the pressure-sensitive adhesive comprises an organic polymer and a plasticizer, wherein the volume-average particle size of the first organic particles satisfies (Dv90-Dv10) / Dv50 ≤ 2.5, optionally ≤ 2, and further optionally ≤ 1.8, and the vitrification transfer temperature of the first organic particles is 20-100°C, optionally 30-80°C, and optionally the separator is 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 , selectively 0.5g·m -2 ·Ω -1 ≤ρ / R ≤0.9g·m -2 ·Ω -1 Furthermore, selectively 0.6 g·m -2 ·Ω -1 ≤ρ / R ≤0.8g·m -2 ·Ω -1 The following conditions are met, where ρ represents the surface density of the coating on the substrate, and R represents the resistance of the separator at 25°C.

[0044] A third aspect of this application provides a secondary battery comprising a positive electrode plate, a negative electrode plate, a separator located between the positive electrode plate and the negative electrode plate, and an electrolyte, wherein the separator is a separator according to the first aspect of this application or a separator manufactured by the method according to the second aspect of this application.

[0045] In each embodiment, selectively, the adhesive force between the positive electrode plate and the separator of the secondary battery satisfies 1.2 ≤ F2 / F1 ≤ 4, and selectively, 1.5 ≤ F2 / F1 ≤ 3.8, where F1 represents the adhesive force between the positive electrode plate and the separator at 25°C and ≥ 2 MPa, and F2 represents the adhesive force between the positive electrode plate and the separator at 95°C and ≥ 2 MPa.

[0046] A fourth aspect of this application provides a battery module, which includes a secondary battery as described in the third aspect of this application. The battery module can be manufactured by employing methods commonly used in the art.

[0047] A fifth aspect of this application provides a battery pack comprising at least one of the secondary battery described in the third aspect of this application or the battery pack described in the fourth aspect of this application. The battery pack can be manufactured by employing methods commonly used in the art.

[0048] A sixth aspect of this application provides a power consumption device comprising at least one of a secondary battery according to a third aspect of this application, a battery module according to a fourth aspect of this application, or a battery pack according to a fifth aspect of this application. The power consumption device can be manufactured by employing methods commonly used in the art. [Effects of the Invention]

[0049] The separator according to this application comprises a substrate and a coating applied to at least one surface of the substrate, wherein the coating comprises 40-90 wt% of first organic particles, 2-15 wt% of a pressure-sensitive adhesive polymer, and optionally 0-50 wt% of second organic particles. The pressure-sensitive adhesive comprises an organic polymer and a plasticizer, and the combined action of both allows the pressure-sensitive adhesive to have good pressure-sensitive properties, thereby giving the coating good pressure-sensitive properties, and furthermore, the separator also has good pressure-sensitive properties. In particular, the separator exhibits slight adhesion to the electrode plate at room temperature (generally 20-30°C, e.g., 25°C) and a pressure of ≤1 MPa, but exhibits clear adhesion to the separator electrode plate at room temperature and a pressure of ≥2 MPa, and the adhesion between the separator and the electrode plate is significantly improved, especially at 95°C and a pressure of ≥2 MPa. This allows for close contact between the electrode plates and separator of the electrochemical device at room temperature, thereby preventing misalignment during production transfer, effectively preventing wrinkles in the negative electrode due to insufficient adhesion between the separator and electrode plates, and further ensuring the structural stability of the electrochemical device. This is advantageous for increasing the yield of shell insertion, thereby improving the shaping and safety performance of the battery core and reducing production costs. On the other hand, the separator according to this application does not adhere excessively during winding and storage, making it convenient for use in the subsequent manufacture of battery cores. Selectively, the volume-average particle size of the first organic particles satisfies (Dv90-Dv10) / Dv50 ≤ 2.5, and the vitrification transfer temperature is 20°C-100°C, which is advantageous for improving the application of the adhesive coating and avoiding blockage of the separator holes, thereby avoiding an increase in the internal resistance of the separator. Finally, selectively, the separator described in this application has a particle size of 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 By satisfying these conditions, it is advantageous to ensure an appropriate separator coating surface density and to avoid excessive separator resistance, thereby achieving both the manufacturing yield and dynamic performance requirements for the battery core.

[0050] The battery module, battery pack, and power consumption device described in this application include the separator described in the first aspect of this application or the secondary battery described in the second aspect of this application, and therefore have the same advantages as the separator or secondary battery of this application. [Brief explanation of the drawing]

[0051] To more clearly illustrate the technical concept of the embodiments of this application, the following is a brief introduction to the drawings that may be used in the embodiments of this application. It is obvious that the drawings described below represent only a few embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without expending any creative effort. [Figure 1] This is a schematic diagram of a secondary battery according to one embodiment of the present application. [Figure 2] This is a schematic diagram of a battery module according to one embodiment of the present application. [Figure 3] This is a schematic diagram of a battery pack according to one embodiment of the present application. [Figure 4] Figure 3 is a schematic diagram of the exploded view. [Figure 5] This is a schematic diagram of a power consumption device according to one embodiment of the present application. [Figure 6] Figures 6-a, 6-b, and 6-c show topographic images of the pressure-sensitive coating of a separator manufactured according to one embodiment of this application, with scanning electron microscope images at different magnifications. [Figure 7] Figures 7-a, 7-b, and 7-c show topographic images of the pressure-sensitive coating of a separator manufactured according to one embodiment of this application, with scanning electron microscope images at different magnifications. [Modes for carrying out the invention]

[0052] The following describes in detail embodiments of the separator, its manufacturing method, secondary battery, battery module, battery pack, and power consumption device of this application, with appropriate reference to the drawings. However, unnecessary detailed explanations may be omitted. For example, detailed explanations of well-known matters and redundant explanations of structures that are actually the same may be omitted. This is to avoid making the following explanation unnecessarily long and to make it easily understandable to those skilled in the art. The drawings and the following explanation are provided to enable those skilled in the art to fully understand this application and do not limit the topics described in the claims.

[0053] The “range” disclosed in this application is limited in the form of a lower limit and an upper limit, and a given range is limited by selecting one lower limit and one upper limit, which define the boundary of a particular range. The range thus limited may or may not include the endpoints, and any combination is possible, that is, any lower limit can be combined with any upper limit to form a range. For example, if the ranges 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges 60-110 and 80-120 can also be assumed. Furthermore, if the minimum range values ​​are listed as 1 and 2, and the maximum range values ​​are listed as 3, 4 and 5, then the ranges 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5 can all be assumed. In this application, unless otherwise specified, the numerical range “ab” represents an abbreviated expression for any combination of real numbers a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have already been listed in this specification, and "0-5" is simply an abbreviated representation of combinations of these numbers. Also, when a parameter is described as an integer ≥ 2, it is equivalent to disclosing that this parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0054] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical inventions.

[0055] Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical concepts.

[0056] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the fact that the method includes steps (a) and (b) means that the method may include steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, the fact that the method referred to above may further include step (c) means that step (c) may be added to the method in any order, for example the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), and so on.

[0057] Unless otherwise specified, the terms “includes” and “inclusion” as used in this application may be open or closed. For example, “includes” and “inclusion” may mean that other components not listed may be included or inclusion, or that only the listed components may be included or inclusion.

[0058] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the conditions A is true (or exists) and B is false (or does not exist), the condition A is false (or does not exist) but B is true (or exists), and the condition both A and B are true (or exist) all satisfy "A or B."

[0059] In the descriptions herein, unless otherwise specified, "greater than or equal to" and "less than or equal to" include the number, and "plural" in "one or more" means two or more.

[0060] It should be explained that in this application, the term "average degree of polymerization" refers to the fact that a polymer consists of identical polymer molecules with different degrees of polymerization, and that degree of polymerization has a statistically average significance. There are two most commonly used methods for expressing the average degree of polymerization: the degree of polymerization obtained by averaging by the number of molecules is called the number-average degree of polymerization, and the degree of polymerization obtained by averaging by weight is called the weight-average degree of polymerization. In this application, the aforementioned "average degree of polymerization" refers to the number-average degree of polymerization.

[0061] It should be explained that in this application, the term "degree of alcohol decomposition" refers to the percentage of hydroxyl groups in the product obtained after alcohol decomposition relative to the original group, and its unit is mole fraction (%). For example, if there are 100 original groups (ester groups) and 60 hydroxyl groups after alcohol decomposition, the degree of alcohol decomposition is 60%.

[0062] It should be explained that in this application, the terms "primary particle" and "secondary particle" have the meanings commonly used in this art. Specifically, a "primary particle" is a particle that does not form an aggregated state, while a "secondary particle" is a particle that forms an aggregated state when two or more primary particles aggregate. Primary and secondary particles can be easily distinguished by scanning electron microscope (SEM) images.

[0063] Secondary batteries are preferred as power sources for power-consuming devices due to their advantages such as high energy density, portability, no storage requirements, and environmental friendliness. In secondary batteries, the separator is a crucial part that guarantees battery safety performance. However, in the manufacturing process of battery cores for electrochemical devices, misalignment of the electrode plates and separator is unavoidable during production transfer. In mild cases, this can cause the electrode plates to wrinkle after full charge, seriously affecting dynamic performance and reducing the safety performance of the battery core. In severe cases, the electrode plates may come into contact with each other, rendering the dry battery core unusable. Therefore, engineers apply an adhesive coating to the separator and generally pre-pressure it with appropriate pressure during the first composite process of the electrode plates and separator of the electrochemical device to ensure a certain level of adhesion before the electrode plates and separator enter the next process. However, due to the demands of production efficiency and considering that relatively high pressure degrades the material structure, the pressure and application time in the first process generally cannot satisfy the requirement for the electrode plates and separator of the electrochemical device to achieve adequate adhesion. Furthermore, in order to ensure the margin of the battery core group and the yield of shell insertion, it is generally necessary to sinter the electrode plates and separators of the electrochemical device in a tunnel furnace at 80-100°C for ≥700 s and then apply pressure to ensure close contact between the electrode plates and separators of the electrochemical device. Therefore, if the matching relationship between the adhesive strength between the separator and electrode plates at room temperature (25°C) and the adhesive strength at high temperatures (e.g., 95°C) is poor, the adhesion of the battery core may be insufficient or excessive, and the resistance of the separator may increase significantly, degrading the dynamic performance of the battery core and potentially leading to safety risks.

[0064] On the other hand, proper adhesion is also necessary between the separators during transport. If the adhesive force is too strong, it may cause the separator layers to adhere to each other, which is detrimental to the high-speed compounding of the subsequent electrode plates and separators. Furthermore, in the course of their research, the inventors discovered that an inappropriate adhesive material and an inappropriate surface density of the adhesive material can lead to blockage of the separator holes, potentially resulting in a decrease in the manufacturing yield of the battery core and a decrease in the dynamic performance of the battery core.

[0065] To solve the above problem, the inventors conducted extensive research and found that by coating the separator substrate with a pressure-sensitive adhesive coating, they could relatively well achieve low viscosity at low pressure and high viscosity at high pressure. Furthermore, the coating density of the pressure-sensitive coating and the resistance of the separator were 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 We discovered that by adjusting the separator to satisfy the following conditions, the resistance of the separator can be further reduced, thereby improving the dynamic performance of the secondary battery employing the separator.

[0066] Separator A first aspect of this application provides a separator, which is a separator, Substrate and, The coating comprises a coating applied to at least one surface of the substrate, wherein the coating comprises 40-90 wt% of first organic particles, 2-15 wt% of a pressure-sensitive adhesive, and optionally 0-50 wt% of second organic particles. The first organic particles comprise an organic polymer and an inorganic substance, and the pressure-sensitive adhesive comprises an organic polymer and a plasticizer. Selectively, the volume-average particle size of the first organic particles satisfies (Dv90-Dv10) / Dv50 ≤ 2.5, selectively ≤ 2, and further selectively ≤ 1.8, and the vitrification transfer temperature of the first organic particles is 20-100°C, selectively 30-80°C. Selectively, the separator is 0.1 g·m³ -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω-1 , selectively 0.5g·m -2 ·Ω -1 ≤ρ / R ≤0.9g·m -2 ·Ω -1 Furthermore, selectively 0.6 g·m -2 ·Ω -1 ≤ρ / R ≤0.8g·m -2 ·Ω -1 The following conditions are met, where ρ represents the surface density of the coating on the substrate, and R represents the resistance of the separator at 25°C.

[0067] This application relates to applying a coating to at least one surface of a porous separator substrate, comprising 40-90 wt% of a first organic particle, 2-15 wt% of a pressure-sensitive adhesive, and optionally 0-50 wt% of a second organic particle. The pressure-sensitive adhesive comprises an adhesive polymer and a plasticizer, and through the combined action of both, the pressure-sensitive adhesive polymer can have good pressure-sensitive properties, thereby giving the coating good pressure-sensitive properties, and furthermore, the separator also has good pressure-sensitive properties. In particular, the separator exhibits slight adhesion to the electrode plate under pressure of ≤1 MPa, but exhibits clear adhesion to the electrode plate under pressure of ≥2 MPa, and the adhesion between the separator and the electrode plate is significantly improved, especially at 95°C and pressure of ≥2 MPa. This allows for close contact between the electrode plate and separator of the electrochemical device at room temperature, thereby preventing misalignment during production transfer, effectively preventing wrinkles in the negative electrode due to insufficient adhesion between the separator and electrode plate, and further ensuring the structural stability of the electrochemical device. This is advantageous for increasing the yield of shell insertion, thereby improving the shaping and safety performance of the battery core and reducing production costs. On the other hand, the separator according to this application does not adhere during winding and storage, making it convenient for use in the subsequent manufacture of battery cores. Selectively, the volume-average particle size of the first organic particles satisfies (Dv90-Dv10) / Dv50 ≤ 2.5, and the vitrification transfer temperature is 20°C-100°C, which is advantageous for improving the application of the adhesive coating and avoiding blockage of the separator hole. Finally, selectively, the separator described in this application is 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 Satisfying these conditions ensures appropriate separator coating surface density and is advantageous in reducing the internal resistance of the separator, thereby achieving both the manufacturing yield and dynamic performance requirements for the battery core.

[0068] In some embodiments, the dry weight ratio of the first organic particles, the second organic particles, and the pressure-sensitive adhesive is selectively 20-90:0-60:8-20, and selectively 30-80:30-50:10-15.

[0069] When the mass ratio of the first organic particles, the second organic particles, and the pressure-sensitive adhesive is within the above range, the permeability and uniformity of the electrolyte distribution can be effectively improved, the synergistic advantages of each component can be fully utilized, and the adhesive performance, dynamic performance, and cycle performance can be improved.

[0070] It should be explained that in this application, the first organic particles are generally designed as primary particles, while the second organic particles are generally designed as secondary particles. The combined action of the first and second organic particles reinforces the adhesion between the separator and the electrode plate, while also effectively ensuring that the separator has a moderately and non-uniformly porous structure, and the coating density ρ of the coating on the separator and the resistance R of the separator at 25°C are 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 This is advantageous in satisfying the following conditions. For example, the ρ / R of the coating is 0.52 g·m -2 ·Ω -1 , 0.65g·m -2 ·Ω -1 , 0.8gm -2 ·Ω -1 , 0.83g·m -2 ·Ω -1 , 0.9g·m -2 ·Ω -1 , 0.96g·m -2 ·Ω -1 Or 0.98 g·m -2 ·Ω -1 This range consists of both of these.

[0071] It should be explained that in this application, both the first organic particles and the pressure-sensitive adhesive contain an organic polymer. To facilitate distinction, the organic polymer contained in the first organic particles may be called the "first organic polymer," and the organic polymer in the pressure-sensitive adhesive may be called the "third organic polymer."

[0072] In some embodiments, the coating density on the separator of the coating is selectively set to 0.1–1.9 g / m². 2 Therefore, selectively 0.25-1.5 g / m 2 Furthermore, it is selectively 0.65-1.2 g / m 2 That is the case.

[0073] Furthermore, in the manufacturing process of the battery core, the fact that the first organic particles are primary particles helps to form a uniform coating interface, and can effectively improve the problem of tab misalignment during the manufacturing of the battery core.

[0074] [First organic particle] In some embodiments, the volume-average particle size Dv50 of the first organic particles is selectively 3–36 μm, and selectively 5–20 μm. For example, it may be in the range of 3 μm, 5 μm, 20 μm, 30 μm, or 36 μm, or any two of these.

[0075] When the volume-average particle size Dv50 of the first organic particles is within the above range, the first organic particles have a relatively large average particle size, which on the one hand increases the effective contact area between the electrode plate and the separator, and can further significantly enhance the adhesion between the electrode plate and the separator, while on the other hand prevents these organic particles from penetrating the holes formed on the separator substrate. At the same time, the presence of relatively large gaps in the large size solves the problem of poor air permeability of the separator, reduces the possibility of small particles blocking the separator holes, and reduces the risk of increased internal resistance. Furthermore, because the compounding of corners is difficult during the manufacturing process of the battery core (especially for prismatic housing batteries), the separator and electrode plate are not bonded at these points, and the separator cannot effectively transfer and release the stress accumulated on the electrode plate to its surroundings. Moreover, due to the structural characteristics of the battery core module itself in prismatic housing batteries, the corners are punctured, and the stress formed by the expansion of the electrode plate is difficult to release. Therefore, if there is insufficient space at the corners of the battery, after a certain number of cycles, i.e., when the stress becomes greater than the elongation rate of the copper-aluminum foil, the electrode plate will break, and further penetrate the separator, leading to a serious safety risk. On the other hand, in this application, since the first organic particles have a relatively large average particle size and a certain compressive capacity, when present at the corners of the battery core, they can effectively provide stress-relieving space at the corners. At the same time, by satisfying (Dv90-Dv10) / Dv50≦2.5 for the first organic particles, the variation in separator thickness is relatively small, ensuring that the displacement of the tab due to changes in separator thickness does not increase and the manufacturing yield of the battery core does not decrease.

[0076] In some embodiments, the vitrification transfer temperature of the first organic particles is selectively 20-100°C, and selectively 30-80°C. For example, it may be in the range of 20°C, 30°C, 40°C, 60°C, 80°C, or 100°C, or any two of these.

[0077] When the glass transition temperature of the first organic particles is within the above range, it can withstand the swelling of the electrolyte. On the one hand, without consuming excessive electrolyte, the residual monomers are vaporized by the electrolyte to block the separator, which is less likely to affect the kinetic performance of the battery core. On the other hand, the adhesion between the separator and the electrode plate does not significantly decrease, and the electrode plate is less likely to be pressured by the first organic particles and the safety performance is less likely to decrease.

[0078] In some embodiments, optionally, the weight average molecular weight of the organic polymer in the first organic particles is 500×10 3 g / mol - 1000×10 3 g / mol, and optionally 800×10 3 g / mol - 1000×10 3 g / mol. The weight average molecular weight can be measured by methods commonly used in the art, for example, by gel permeation chromatography referring to GB / T 21863-2008.

[0079] In some embodiments, optionally, the first organic particles in the separator of the present application contain an organic polymer and an inorganic substance, where the organic polymer in the first organic particles is at least A first polymerizable monomer having at least one ester bond and selectively being one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, vinyl acetate, trifluoroethyl methacrylate, glycidyl methacrylate, or trimethylolpropane triacrylate, and further selectively being one or more of methyl methacrylate, lauryl acrylate, lauryl methacrylate, or trimethylolpropane triacrylate, A second polymerizable monomer having at least one cyanide bond, selectively being one or more of acrylonitrile, methacrylonitrile, and ethacrylonitrile, and further selectively being one or more of acrylonitrile and methacrylonitrile, It is polymerized with a monomer having at least one amide bond, which is selectively one or more of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide, and further selectively one or more of acrylamide and N-methylolacrylamide, Selectively, the weight ratios of the first polymerizable monomer, the second polymerizable monomer, and the third polymerizable monomer are 1:0-0.8:0.05-0.75 and selectively 1:0.1-0.6:0.1-0.6.

[0080] When an organic polymer is produced by polymerizing the above polymerizable monomers, the first organic particles produced possess good adhesive properties as well as a relatively low vitrification transfer temperature. Furthermore, the spray surface density ρ of the adhesive material on the separator and the resistance of the separator are R0.1g·m². -2 ·Ω -1≦ρ / R≦1.0 g·m -2 ·Ω -1 By satisfying this, the resistance of the separator is reduced, which helps to improve the kinetic performance of the battery employing this separator.

[0081] In some embodiments, optionally, the content of the organic polymer in the first organic particles is 50 - 99.9% based on the total dry weight of the first organic particles, optionally 60 - 99%, and further optionally 70 - 99%, the content of the inorganic substance in the first organic particles is 0.1 - 50% based on the total dry weight of the first organic particles, optionally 1 - 40%, and further optionally 1 - 30%.

[0082] If the content of the organic polymer in the first organic particles is too low or the content of the inorganic substance is too high, the adhesion performance of the whole first organic particles is insufficient, and as a result, there is a possibility that the organic polymer and the inorganic substance cannot be held together. If the content of the inorganic substance in the first organic particles is too low, the flame retardancy of the first organic particles may be relatively poor.

[0083] In some embodiments, optionally, the weight ratio of the organic polymer to the inorganic substance in the first organic particles is 99:1 - 1:1, optionally 70:30 - 1:1.

[0084] When the weight ratio of the organic polymer to the inorganic substance in the first organic particles is within the above range, it is advantageous to fully exert the synergistic function of the organic polymer and the inorganic substance and endow the first organic particles with good adhesion performance and flame retardancy.

[0085] In some embodiments, optionally, based on the total weight of the organic polymer in the first organic particles, the content of the first polymerizable monomer is 35 - 80% by weight, optionally 45 - 70% by weight, the content of the second polymerizable monomer is 0 - 30% by weight, optionally 5 - 25% by weight, and The content of the third polymerizable monomer is 5-40% by weight, and selectively 8-35% by weight.

[0086] When the content of the first polymerizable monomer, the second polymerizable monomer, and the third polymerizable monomer are all within the above range, the cooperative advantages of each monomer are fully utilized, which is advantageous for improving the adhesive performance of the organic polymer, while also providing an appropriate vitrification transfer temperature and further improving the adhesive performance of the first organic particles.

[0087] In some embodiments, the inorganic material in the first organic particle is selectively selected from one or more of silicon, aluminum, calcium, zinc, magnesium oxides and sodium sulfate, sodium benzoate, calcium carbonate and their modifiers, selectively selected from one or more of silicon dioxide, silica sol, aluminum oxide, zinc oxide, magnesium oxide, and sodium benzoate, and further selectively selected from one or more of fumed silicon dioxide, silicon powder, aluminum oxide, and sodium benzoate.

[0088] In some embodiments, the surface of the first organic particles is selectively uneven, with inorganic oxide clusters having a particle size of 10-200 nm uniformly distributed therein.

[0089] This application further provides a method for producing the first organic particles of this application, the method comprising at least the following steps:

[0090] Step 1: Provide a first polymerizable monomer, a second polymerizable monomer, and a third polymerizable monomer, the weight ratio of the first polymerizable monomer to the second polymerizable monomer and the third polymerizable monomer being 1:0-0.8:0.05-0.75, and selectively 1:0.1-0.6:0.1-0.6. Step 2: Polymerize the polymerizable monomer to obtain an organic polymer. Step 3: Add organic solvent and inorganic substance to the organic polymer from Step 2, stir, and obtain a mixed slurry. Step 4: The mixed slurry from Step 3 is dried, polished, and ground to obtain the first organic particles described in this application.

[0091] It should be noted that the polymerization of polymerizable monomers may be carried out by polymerization methods commonly used in this field, such as emulsion polymerization or suspension polymerization.

[0092] In some embodiments, additives, such as emulsifiers, such as sodium lauryl sulfate, and polymerization initiators, such as ammonium persulfate, may be selectively added to the polymerization system of the polymerizable monomer.

[0093] [Pressure-sensitive adhesive] The pressure-sensitive adhesive described in this application comprises an organic polymer and a plasticizer.

[0094] In some embodiments, the mass ratio of the organic polymer to the plasticizer contained in the pressure-sensitive adhesive is selectively (4-25):1, and selectively (4-11):1.

[0095] The relative content of plasticizers in the pressure-sensitive adhesive is within the above range, ensuring a relatively high adhesive strength between the electrode plate and the separator, which is advantageous for improving adhesive performance and cycle performance without significantly increasing the separator's resistance.

[0096] In some embodiments, the pressure-sensitive adhesive selectively has a core-shell structure, where both the core and housing of the core-shell structure contain an organic polymer and a plasticizer, where the mass ratio of the organic polymer to the plasticizer in the core is (3-4):1, selectively (3.2-3.8):1, and the mass ratio of the organic polymer to the plasticizer in the housing structure is (7-9):1, selectively (7.5-8.5):1.

[0097] In a core-shell structure, both the core and housing are composed of organic polymers and plasticizers, which further improves the pressure-sensitive performance of the pressure-sensitive adhesive, thereby improving the applicability of the separator to different pressure modes and favoring a reduction in separator resistance, thereby enhancing the separator's dynamic performance. On the other hand, the pressure-sensitive adhesive contains a plasticizer, and under a certain pressure (e.g., 1-2 MPa), the plasticizer rapidly migrates between the organic polymer and the separator main material, plasticizing the adhesive polymer and extending its molecular chains. This generates intermolecular hydrogen bonding with, for example, styrene-butadiene rubber (SBR) adhesives and carboxymethylcellulose sodium (CMC) thickeners on the negative electrode plate, and with adhesives on the positive electrode plate, for example, polyvinylidene fluoride (PVDF), increasing interfacial wettability and reinforcing the riveting action between the two interfaces. Under pressures of ≥2 MPa, the core structure is broken down, releasing the plasticizer in the core, further improving the above effects.

[0098] In some embodiments, selectively, in the pressure-sensitive adhesive, a portion of the plasticizer is grafted onto the organic polymer, and selectively, in the pressure-sensitive adhesive, at least 5 wt% of the plasticizer, based on the weight of the plasticizer, is grafted onto the organic polymer. For example, 0 wt%, 3 wt%, 5 wt%, or 8 wt% of the plasticizer may be grafted onto the organic polymer, and selectively, 8 wt% of the plasticizer may be grafted onto the organic polymer.

[0099] When a portion of the plasticizer is grafted onto the organic polymer, it is possible to prevent large amounts of the plasticizer from migrating into the electrolyte during the cycle, thereby consuming various functional additives in the electrolyte, increasing the resistance of the separator, and avoiding an impact on the dynamic performance of the battery core. In particular, when at least 5 wt% of the plasticizer is grafted onto the organic polymer main chain, the separator and the electrode can form a "separated yet connected" effect, further enhancing the durability of room-temperature bonding, reducing repulsion, and further ensuring that excess plasticizer does not migrate into the electrolyte during the cycle, thus preventing an impact on the performance of the battery core.

[0100] It should be noted that the graft ratio can be adjusted by methods well known in this field, for example, by adjusting the synthesis time. For further details, refer to the patent document with PCT application number PCT / CN2021 / 143069.

[0101] The graft rate may be tested by methods commonly used in this field, such as infrared testing. For example, this may be done by the following steps: Obtain Fourier infrared spectrograms from the tests of the organic polymer, plasticizer, and pressure-sensitive adhesive, and the pressure-sensitive adhesive at 1500-1700 cm². -1 At this position, a peak distinct from that of the organic polymer and the plasticizer alone appears. This peak represents the grafted plasticizer, and the area under the peak represents the amount of grafted plasticizer, thereby allowing the grafting rate of the plasticizer to be calculated.

[0102] In some embodiments, the volume-average particle size Dv50 of the pressure-sensitive adhesive is selectively 0.3–3.5 μm, and selectively 0.8–2.0 μm. For example, it may be in the range of 0.3 μm, 0.5 μm, 0.8 μm, 1.0 μm, 2.0 μm, 3.0 μm, or 3.5 μm, or any two of these.

[0103] A pressure-sensitive adhesive with an appropriate particle size helps to be uniformly distributed on the first or second organic particles, contributing to the adhesion between the core and housing and the electrode plate at a constant pressure, and to the effective improvement of the separator's resistance.

[0104] In some embodiments, the vitrification transfer temperature of the pressure-sensitive adhesive is selectively -50°C to 100°C, and selectively -45°C to 60°C.

[0105] When the vitrification transfer temperature of the pressure-sensitive adhesive polymer is within the above range, it is advantageous for ensuring adhesive strength at room temperature, avoiding the adhesive strength being greater than 0.08 N / m at room temperature and 1 MPa, which would cause the separator to curl and adhere, and also avoiding the adhesive strength being less than 0.1 N / m at room temperature and 2 MPa, which would result in weak adhesion between the separator and the electrode plate, making it unfavorable for shaping the battery core.

[0106] In some embodiments, selectively, the pressure-sensitive adhesive comprises a copolymer obtained by copolymerizing a mixture of at least one of the following first monomer group, at least one of the second monomer group, at least one of the third monomer group, and at least one of the reactive dispersants, i.e., The first group of monomers generally has a melting point higher than 80°C and includes acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylolacrylamide, acrylamide, styrene, and acrylonitrile. The second group of monomers generally has a melting point of 80°C or lower, and is acrylic acid C4-C 22Alkyl esters, such as isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate (isoooctyl acrylate), cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, ethyleneurea ethyl methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylic methacrylate, and dicyclopentenyloxyethyl methacrylate, The third group of monomers is a crosslinkable monomer comprising at least one of a hydroxyl group, an amino group, and a double bond, and includes 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, γ-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethacrylamide, diacetoneacrylamide (DAAM), acetate acetate methacrylate (AAEM), divinylbenzene, epoxy resins with an epoxy value of 0.35-0.50, and divinylbenzene. The reactive dispersant includes polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, and polyvinyl alcohol.

[0107] In some embodiments, the mass ratio of the first monomer group monomer, the second monomer group monomer, the third monomer group monomer, and the reactive dispersant is selectively 35-45:45-60:4-8:2-5.

[0108] In this application, the reactive dispersant plays a role in dispersion during the synthesis of a pressure-sensitive adhesive by copolymerizing with the first monomer, the second monomer, and the third monomer. Selectively, the degree of alcohol decomposition of these reactive dispersants is ≥85% and the number average degree of polymerization is 400-2000, and selectively, the degree of alcohol decomposition is ≥88% and the number average degree of polymerization is 500-1600.

[0109] In some embodiments, the plasticizer is selectively glycerol C4-C 10 Alkyl diether or monoether, glycerol C4-C 10 Carboxylic acid monoester or diester, propylene glycol C4-C 10 Selected from one or more alkyl monoethers or glycerols.

[0110] In some embodiments, the pressure-sensitive adhesive polymer can be selectively manufactured with reference to the patent document with PCT application number PCT / CN2021 / 143069, all of which are incorporated herein by reference.

[0111] In some embodiments, the pressure-sensitive adhesive polymer may be selectively synthesized according to a method comprising the following steps.

[0112] Step 1: Add the emulsifier and oligomer to the solvent, disperse them uniformly, and obtain the first mixed solution. Step 2: Add the stabilizer to the first mixed solution and disperse it uniformly to obtain the second mixed solution. Step 3: Add the aqueous initiator to the second mixed solution, mix uniformly, and react at 60-80°C for 20-60 minutes to obtain the third mixed solution. Step 4: While stirring, uniformly add the reaction monomer mixture dropwise to the third mixed solution to obtain the fourth mixed solution after 80-100 minutes, for example, 80 minutes. Step 5: Heat the fourth mixed solution to 80-90°C, for example 84°C, and continue stirring for 120-240 minutes, for example 180 minutes, to obtain the fifth mixed solution. Step 6: Add the plasticizer to the fifth mixed solution and react at 80-90°C, for example 84°C, for 120-240 minutes, for example 180 minutes, to obtain the sixth mixed solution. Step 7: Add the aqueous initiator to the sixth mixed solution and react at 60-80°C, e.g., 72°C, for 20-60 minutes, e.g., 30 minutes, to obtain the seventh mixed solution. Step 8: While stirring, uniformly add the reaction monomer mixture dropwise to the seventh mixed solution to obtain the fourth mixed solution after 100-160 minutes, for example, 120 minutes. Step 9: Add the plasticizer to the eighth mixed solution and react at 80-90°C, for example 84°C, for 120-240 minutes, for example 180 minutes, to obtain the ninth mixed solution. Step 10: The ninth mixed solution is cooled to below 50°C and filtered to obtain a pressure-sensitive adhesive.

[0113] In some embodiments, the solvent used in step 1 is selectively deionized water.

[0114] In some embodiments, 0.1–1% by weight of an emulsifier and 2–3% by weight of an oligomer are selectively added in step 1, based on the total weight of the reaction monomer mixture (including monomers from the first monomer group, monomers from the second monomer group, monomers from the third monomer group, and a reactive dispersant), auxiliary agents (including emulsifiers, stabilizers, and aqueous initiators) and plasticizers added when synthesizing the pressure-sensitive adhesive, and the same applies hereafter.

[0115] In some embodiments, the emulsifier is selectively selected from one or more of propyl sulfonates, polyoxyethylene alkyl ethers, polyoxyethylene aryl ethers, and sorbitol.

[0116] In some embodiments, the stabilizer is selectively selected from one or more of polyethylene oxide, allyl polyether sulfate, methylene succinic acid (itaconic acid), styrene sulfonic acid, sodium vinyl sulfonate, and sodium nanocellulose.

[0117] In some embodiments, the aqueous initiator is selectively selected from one or more of the following: sodium bicarbonate, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxybenzoate, t-butyl peroxypivalate, methyl ethyl ketone peroxide, cyclohexanone peroxydiisopropyl carbonate, dicyclohexyl peroxydicarbonate, potassium persulfate, sodium persulfate, ammonium persulfate, azobisisobutyronitrile, azobisisoheptonitrile, and ammonium persulfate-sodium bicarbonate.

[0118] In some embodiments, the number-average molecular weight of the oligomer is selectively ≤ 1000, and the melting point is 0-30°C.

[0119] In some embodiments, the oligomer is selectively selected from, for example, stearyl methacrylate.

[0120] In some embodiments, uniform distribution is selectively achieved in step 1 by distributing the material for 20-60 minutes, for example, 50 minutes, at a rotational speed of 8000-12000 r / min (revolutions per minute), for example, 10000 r / min.

[0121] In some embodiments, the operating temperature in step 1 is selectively 20-40°C, for example, 25°C.

[0122] In some embodiments, 1-4% by weight of a stabilizer is selectively added to the first mixed solution in step 2.

[0123] In some embodiments, uniform mixing is selectively achieved in step 2 by mixing at 6000-8000 r / min, for example 6500 r / min, for 20-60 minutes, for example 30 minutes.

[0124] In some embodiments, the operating temperature in step 2 is selectively 20-60°C, for example, 45°C.

[0125] In some embodiments, 0.05–0.5% by weight of an aqueous initiator is selectively added to the second mixed solution in step 3.

[0126] In some embodiments, uniform mixing is selectively achieved in step 3 by mixing at 8000-12000 r / min, for example 8000 r / min for 20-60 minutes, for example 30 minutes.

[0127] In some embodiments, the operating temperature in step 3 is selectively 60-80°C, for example, 72°C.

[0128] In some embodiments, 35%–45% by weight of the reaction monomer mixture is selectively added dropwise to the third mixed solution in step 4.

[0129] In some embodiments, the stirring speed in step 4 is selectively 100-1000 r / min, for example, 400 r / min.

[0130] In some embodiments, selectively, the dripping is completed in step 4, preferably in 60 minutes.

[0131] In some embodiments, selectively, the stirring speed in step 5 is 12,000-18,000 r / min, for example, 15,000 r / min.

[0132] In some embodiments, 10-20% by weight of a plasticizer, such as glycerol, is selectively added to the fifth mixed solution in step 6.

[0133] In some embodiments, selectively, the stirring speed in step 6 is 12,000-18,000 r / min, for example, 15,000 r / min.

[0134] In some embodiments, 0.05–0.5% by weight of an aqueous initiator is selectively added to the sixth mixed solution in step 7.

[0135] In some embodiments, the stirring speed in step 7 is selectively 8000-12000 r / min, for example, 8000 r / min.

[0136] In some embodiments, 30%–40% by weight of the reaction monomer mixture is selectively added dropwise to the seventh mixed solution in step 8.

[0137] In some embodiments, the stirring speed in step 8 is selectively 100-1000 r / min, for example, 400 r / min.

[0138] In some embodiments, selectively, in step 8, the dropwise addition of the reaction monomer mixture is completed in exactly 60 minutes.

[0139] In some embodiments, 5-20% by weight of a plasticizer, such as glycerol, is selectively added to the eighth mixed solution in step 9.

[0140] In some embodiments, selectively, the stirring speed in step 9 is 12,000-18,000 r / min, for example, 15,000 r / min.

[0141] It should be noted that those skilled in the art can also synthesize and obtain non-core-shell structured pressure-sensitive adhesive polymers by referring to the above method (omitting steps 7-9 and accordingly changing the mass fraction of the plasticizer and reaction monomer mixture to be added).

[0142] [Second organic particle] The separator coating described in this application further selectively includes a second organic particle.

[0143] In some embodiments, the second organic particles are selectively polymers of one or more monomers, including halogens, phenyl groups, epoxy groups, cyano groups, ester groups, and amide groups.

[0144] In some embodiments, the second organic particle is selectively selected from at least one of the following: homopolymers or copolymers of fluorine-containing alkenyl monomer units, homopolymers or copolymers of olefin-based monomer units, homopolymers or copolymers of unsaturated nitrile-based monomer units, homopolymers or copolymers of alkylene oxide-based monomer units, dipolymers, homopolymers or copolymers of monosaccharide monomer units, and modified compounds of each of the above homopolymers or copolymers.

[0145] In some embodiments, the fluorine-containing alkenyl monomer unit is selected from one or more of difluoroethylene, vinylidene fluoride, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, hexafluoropropylene, or derivatives thereof.

[0146] In some embodiments, the olefin monomer unit is selected from one or more of ethylene, propylene, butadiene, isoprene, styrene, or their derivatives.

[0147] In some embodiments, the unsaturated nitrile monomer unit is selected from one or more of acrylonitrile, methacrylonitrile, or their derivatives.

[0148] In some embodiments, the alkylene oxide monomer unit is selected from one or more of ethylene oxide, propylene oxide, or derivatives thereof.

[0149] In some embodiments, the monosaccharide monomer unit is selected from glucose or its derivatives.

[0150] In some embodiments, the second organic particle is selected from at least one of polyperfluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polystyrene-co-methyl methacrylate, polystyrene-co-butyl acrylate, styrene-butyl acrylate-isooctyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyethylene-co-vinyl acetate, polyimide, polyethylene oxide, cellulose acetate, cellulose butyrate acetate, cellulose propionate acetate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethylcellulose, and cyanoethyl sucrose.

[0151] In some embodiments, the second organic particle may be at least one selected from polyvinylidene fluoride-co-hexafluoropropylene, polystyrene-co-butyl acrylate, styrene-butyl acrylate-isooctyl acrylate, polyperfluoroethylene, polyvinylidene fluoride, and polyvinylidene fluoride-co-trichloroethylene.

[0152] The second organic particles may be similar to the first organic particles and may be produced by polymerization methods commonly used in the art, such as emulsion polymerization or suspension polymerization.

[0153] In some embodiments, the second organic particle is (1) The volume-average particle size Dv50 of the second organic particle is 2-20 μm, and selectively 6-15 μm. (2) The melting point of the second organic particle is 130-160°C, and selectively 138-150°C. (3) The weight-average molecular weight of the second organic particle is 400 × 10 3 g / mol - 1000 × 10 3 g / mol, selectively 450 × 10 3 g / mol - 650 × 10 3 It is g / mol, It satisfies one or more of the following conditions.

[0154] By employing a second organic particle within the specified particle size range, the secondary battery can further form sufficient and uniformly distributed gaps between the first and second organic particles during normal operation, ensuring smoother ion transmission channels and thereby providing the battery with even better cycle performance. The combined action of the first and second organic particles reinforces the adhesion between the separator and the electrode plate, while also effectively ensuring that the separator has an appropriate and non-uniform pore structure.

[0155] The melting point of the second organic particle is within the above range, allowing it to withstand the swelling of the electrolyte. On the other hand, it does not consume excess electrolyte, and the residual monomer is bubbled by the electrolyte, blocking the separator and thus minimizing the impact on the dynamic performance of the battery core. On the other hand, the adhesion between the separator and the electrode plate is not significantly reduced, and the electrode plate is less likely to suffer pressure loss due to the second organic particle, thus reducing its safety performance.

[0156] For example, the volume-average particle size Dv50 of the second organic particle may be 2 μm, 8 μm, 10 μm, or 12 μm.

[0157] In some embodiments, the separator is (1) The porosity of the substrate is 10-95%. (2) The pore diameter of the substrate is 20-60 nm. (3) The thickness of the substrate is 3-12 μm, and selectively 5-9 μm. (4) The substrate is a film or nonwoven fabric selected from one or more of polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cycloolefin copolymer, polyphenylene sulfide, and polyethylene naphthalene. It satisfies one or more of the following conditions.

[0158] If the separator satisfies one or more of the above conditions, it is advantageous for further improving the adhesive performance of the separator and the kinetic and cyclic performance of the corresponding secondary battery.

[0159] In some embodiments, selectively, in the separator, the mass ratio of the first organic particles to the second organic particles is 10-100:0-90, and selectively, 20-90:0-60. Selectively, the ratio of the sum of the masses of the first organic particles and the second organic particles to the mass of the pressure-sensitive adhesive is 20-92:8-20, and selectively 60-90:10-15.

[0160] For example, the mass ratio of the first organic particle to the second organic particle may be in the range of 100:0, 90:10, 70:30, 50:50, 40:60, 65:25, or 75:10, or any two of these ratios.

[0161] For example, the ratio of the sum of the masses of the first organic particles and the second organic particles to the mass of the pressure-sensitive adhesive may be in the range of 60:10, 80:10, 85:15, 90:10, or 110:10, or any two of these ratios.

[0162] In some embodiments, the average thickness of the coating is 0.8–22 μm, and selectively 2–15 μm. For example, the average thickness may be in the range of 0.8 μm, 2 μm, 3 μm, 4 μm, 6 μm, 10 μm, 12 μm, 15 μm, 20 μm, or 22 μm, or any two of these.

[0163] Separator manufacturing method A second aspect of this application provides a method for manufacturing a separator as described in the first aspect of this application, the method being Step S1 involves adding the first organic particles and a dispersant to the solvent to form the first polymer solution, Step S2 involves adding a pressure-sensitive adhesive to the first polymer solution obtained in step S1 and mixing thoroughly to form a second polymer solution. Optionally, in step S3, a second organic particle is added to the second polymer solution obtained in step S2 and thoroughly mixed to form a third polymer solution. Step S4 involves applying the second polymer solution obtained in step S2) or the third polymer solution obtained in step S3) to at least one surface of the substrate, drying, and then obtaining a separator. Includes, The separator comprises a substrate and a coating applied to at least one surface of the substrate, wherein the coating comprises 40-90 wt% of first organic particles, 2-15 wt% of a pressure-sensitive adhesive, and optionally 0-50 wt% of second organic particles, wherein the first organic particles comprise an organic polymer and an inorganic substance, and the pressure-sensitive adhesive comprises an organic polymer and a plasticizer, wherein the volume-average particle size of the first organic particles satisfies (Dv90-Dv10) / Dv50 ≤ 2.5, optionally ≤ 2, and further optionally ≤ 1.8, and the vitrification transfer temperature of the first organic particles is 20-100°C, optionally 30-80°C, and optionally the separator is 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 , selectively 0.5g·m -2 ·Ω -1 ≤ρ / R ≤0.9g·m-2 ·Ω -1 Furthermore, selectively 0.6 g·m -2 ·Ω -1 ≤ρ / R ≤0.8g·m -2 ·Ω -1 The following conditions are met, where ρ represents the surface density of the coating on the substrate, and R represents the resistance of the separator at 25°C.

[0164] In some embodiments, non-limiting examples of the dispersant used in step S1 may include acrylates (e.g., BYK brand 22136), branched alcohol polyethers (e.g., Dow brand TMN-6), polyethylene glycol trimethylnonyl ether, or mixtures thereof.

[0165] In some embodiments, non-limiting examples of the solvent used in step S1 may include acetone, tetrahydrofuran, dichloromethane, chloroform, dimethylformamide, N-methyl-2-pyrrolidone, cyclohexane, water, or mixtures thereof.

[0166] In some embodiments, non-limiting examples of the coating method used in step S4 may include dipping, die coating, roller coating, comma coating, spray coating, or a combination thereof. The density of the coated surfaces on both sides after drying is 0.32–1.92 g / m². 2 That's fine.

[0167] [Secondary battery] A third aspect of this application provides a secondary battery having good safety performance and kinetic performance.

[0168] Generally, a secondary battery includes a positive electrode plate, a negative electrode plate, an electrolyte, and a separator. During battery charging, active ions intermittently

[0169] In the secondary battery according to this application, the separator may be a separator according to the first embodiment of this application, which has good ion conductivity and adhesive performance at room temperature, and its resistance at room temperature (generally 20-30°C, e.g., 25°C) is 1.6 Ω or less, particularly 1.2 Ω or less, its adhesive strength at an action of ≤1 MPa is 0.1 N / m or less, particularly 0.08 N / m or less, and its adhesive strength to the electrode plate at ≥2 MPa, room temperature is 0.15 N / m or more, particularly 0.4 N / m or more, and its adhesive strength to the electrode plate at ≥2 MPa, 95°C is 4.9 N / m or less, particularly 1.8 N / m or less.

[0170] When a secondary battery is manufactured using a separator according to the first aspect of this application, the adhesive strength F1 between the positive electrode plate and the separator at room temperature of 25°C and ≥2 MPa, and the adhesive strength F2 between the positive electrode plate and the separator at 95°C and ≥2 MPa, satisfy 1.2 ≤ F2 / F1 ≤ 4, and selectively 1.5 ≤ F2 / F1 ≤ 3.8. At the same time, the surface density ρ coated on the substrate and the resistance R of the separator at 25°C are 0.1 g·m -2 ·Ω -1 ≤ρ / R ≤ 1.0g·m -2 ·Ω -1 , selectively 0.5g·m -2 ·Ω -1 ≤ρ / R ≤0.9g·m -2 ·Ω -1 Furthermore, selectively 0.6 g·m -2 ·Ω -1 ≤ρ / R ≤0.8g·m -2 ·Ω -1The following conditions are met. If F2 / F1 > 4, insufficient pre-cooling press during battery core winding may cause the battery core to swell, misalignment of the separator and electrode plates, and consequently, slippage of the inner electrode plates, potentially creating a safety risk of a wrap short circuit on the electrode plates. Furthermore, inappropriately excessive thermal pressure bonding may lead to difficulty in electrolyte penetration, potentially affecting the chemical conversion efficiency of the battery core. Additionally, black spots may form after full capacity charging, leading to lithium deposition, severely impacting the dynamics and safety performance of the battery core. If F2 / F1 < 1.2, pre-cooling press meets the process requirements, but during the thermal press process through the tunnel furnace, the thickness and width of the battery core may exceed the specifications, causing swelling, or swelling after being left for a certain period of time, potentially reducing the yield of the battery core and decreasing production efficiency. A greater risk is that after being placed in the shell and injected with electrolyte, the hardness of the battery core may drastically decrease, causing the electrode plates to separate from the separator and increasing the expansion force of the battery core. More seriously, if the adhesion between the separator and the electrode plate is too weak, it may not be able to contain the repulsion of the negative electrode, causing wrinkles, leading to lithium deposition problems and potentially degrading the battery's core cycle performance.

[0171] [Positive electrode plate] The positive electrode plate includes a positive electrode current collector and a positive electrode film that is placed on at least one surface of the positive electrode current collector and contains positive electrode active material. For example, the positive electrode current collector has two opposing surfaces in its thickness direction, and the positive electrode film is placed on one or both of the two opposing surfaces of the positive electrode current collector.

[0172] The positive electrode current collector may be made of a material with good conductivity and mechanical strength. In some embodiments, aluminum foil may be used as the positive electrode current collector.

[0173] This application does not specifically limit the type of positive electrode active material, and any material known in the art that can be used as a positive electrode in secondary batteries may be used, and those skilled in the art can select according to their actual needs.

[0174] In some embodiments, the secondary battery according to this application is a lithium-ion secondary battery. The positive electrode active material includes positive electrode active materials for lithium-ion secondary batteries known in the art. For example, the positive electrode active material may include at least one material from among lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective reformed compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may be used. Here, examples of lithium transition metal oxides are lithium cobalt oxide (e.g., LiCoO2), lithium nickel oxide (e.g., LiNiO2), lithium manganese oxide (e.g., LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM 333 (It may also be abbreviated as LiNi) 0.5 Co 0.2 Mn 0.3 O2(NCM 523 (It may also be abbreviated as LiNi) 0.5 Co 0.25 Mn 0.25 O2(NCM 211 (It may also be abbreviated as LiNi) 0.6 Co 0.2 Mn 0.2 O2(NCM 622 (It may also be abbreviated as LiNi) 0.8 Co 0.1 Mn 0.1 O2(NCM 811 (May be abbreviated as LiNi) Lithium nickel cobalt aluminum oxide (e.g., LiNi 0.85 Co 0.15 Al 0.05It may include, but is not limited to, at least one of O2) and its modified compounds. Examples of lithium-containing phosphates with an olivine structure include, but is not limited to, at least one of lithium iron phosphate (e.g., LiFePO4 (which may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (e.g., LiMnPO4), composite materials of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.

[0175] In some embodiments, the mass percentage of the positive electrode active material that occupies the positive electrode film is selectively 75% to 99%, and selectively 80% to 97%.

[0176] In some embodiments, the cathode film may further selectively include an adhesive. The type of adhesive is not specifically limited, and those skilled in the art can select it according to their actual needs. For example, the adhesive used in the cathode film may include one or more of polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE).

[0177] In some embodiments, the mass percentage of the adhesive that occupies the positive electrode film is selectively 0.1% to 3.5%, and selectively 0.5% to 3%.

[0178] In some embodiments, the cathode film further selectively includes a conductive agent. The type of conductive agent is not specifically limited, and those skilled in the art can select one according to their actual needs. For example, the conductive agent used in the cathode film may include one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0179] In some embodiments, the mass percentage of the conductive agent that selectively occupies the positive electrode film is 0.05% to 5%, and selectively 0.5% to 3%.

[0180] In some embodiments, the step of manufacturing a positive electrode plate using a positive electrode active material may include the following: Dispersing the positive electrode active material, adhesive, and selective conductive agent in a solvent, which may be N-methylpyrrolidone, and uniformly stirring with a vacuum mixer to obtain a positive electrode slurry; uniformly coating a positive electrode current collector aluminum foil with the positive electrode slurry; drying at room temperature, then transferring to an oven for drying, and then cold pressing and slitting to obtain a positive electrode plate.

[0181] [Negative electrode plate] The negative electrode plate includes a negative electrode current collector and a negative electrode film placed on at least one surface of the negative electrode current collector. For example, the negative electrode current collector has two opposing surfaces in its thickness direction, and the negative electrode film layer is placed on one or both of the two opposing surfaces of the negative electrode current collector.

[0182] The negative electrode current collector may be made of a material with good conductivity and mechanical strength, and it performs the roles of conductivity and current collection. In some embodiments, copper foil may be used for the negative electrode current collector.

[0183] The negative electrode film contains a negative electrode active material, and the step of manufacturing a negative electrode plate using the negative electrode active material may include the steps of: dispersing the negative electrode active material, adhesive, and selective thickener and conductive agent in a solvent, the solvent may be deionized water, to form a uniform negative electrode slurry; and coating a negative electrode current collector with the negative electrode slurry, and obtaining a negative electrode plate after processes such as drying and cold pressing.

[0184] In some embodiments, this application does not specifically limit the type of negative electrode active material, and the negative electrode plate includes a negative electrode active material that can be selectively used as a negative electrode for a secondary battery. The negative electrode active material may be one or more of the following: graphite materials (e.g., artificial graphite, natural graphite), mesocarbon microbeads (abbreviated as MCMB), hard carbon, soft carbon, silicon-based materials, and tin-based materials.

[0185] In some embodiments, the mass percentage of the negative electrode active material that occupies the positive electrode film is selectively 75% to 99%, and selectively 80% to 97%.

[0186] In some embodiments, the adhesive may be selected from one or more of the following: polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), styrene-butadiene rubber (SBR), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0187] In some embodiments, the mass percentage of the adhesive that selectively occupies the negative electrode film is 0.1% to 3.5%, and selectively 0.5% to 2.5%.

[0188] In some embodiments, the thickener may be sodium carboxymethylcellulose (CMC-Na).

[0189] In some embodiments, the mass percentage of the thickening agent that occupies the negative electrode film is selectively 0.04% to 5%, and selectively 0.5% to 3%.

[0190] In some embodiments, the conductive agent used in the negative electrode plate may be selected from one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0191] In some embodiments, the mass percentage of the conductive agent that selectively occupies the negative electrode film is 0.04% to 5%, and selectively 0.5% to 3%.

[0192] [Electrolyte] The electrolyte plays a role in conducting ions between the positive and negative electrodes. This application does not specifically limit the type of electrolyte, and it can be selected according to the needs. For example, the electrolyte may be a liquid, a gel, or all-solid.

[0193] In some embodiments, an electrolyte solution is used as the electrolyte. The electrolyte solution contains an electrolyte salt and a solvent.

[0194] In some embodiments, the electrolyte salt may be selected from one or more of the following: LiPF6 (lithium hexafluorophosphate), LiBF4 (lithium tetrafluoroborate), LiClO4 (lithium perchlorate), LiAsF6 (lithium hexafluoroarsenate), LiFSI (lithium bis(fluorosulfonyl)imide), LiTFSI (lithium bis(trifluoromethanesulfonyl)imide), LiTFS (lithium trifluoromethanesulfonate), LiDFOB (lithium difluoro(oxalato)borate), LiBOB (lithium bis(oxalato)borate), LiPO2F2 (lithium difluorophosphate), LiDFOP (lithium difluorobis(oxalato)phosphate), and LiTFOP (lithium tetrafluoro(oxalato)phosphate).

[0195] In some embodiments, the concentration of the electrolyte salt in the non-aqueous electrolyte is, for example, 0.3 mol / L (moles / liter) or more, selectively 0.7 mol / L or more, selectively 1.7 mol / L or less, and even more selectively 1.2 mol / L or less.

[0196] In some embodiments, the solvent may be selected from one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS), and diethyl sulfone (ESE).

[0197] In some embodiments, the electrolyte further selectively includes additives. For example, the additives may include negative electrode film forming additives, positive electrode film forming additives, and further additives that can improve some of the battery's performance characteristics, such as additives that improve the battery's overcharge performance, additives that improve the battery's high-temperature performance, and additives that improve the battery's low-temperature performance.

[0198] [Exterior] In some embodiments, the secondary battery may include an outer casing for packaging a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. For example, the positive electrode plate, negative electrode plate, and separator may form a laminated or wound battery core, the battery core being packaged within the outer casing, and the electrolyte may be a liquid electrolyte, which is impregnated into the battery core. The number of battery cores in the secondary battery may be one or more and can be adjusted according to the requirements.

[0199] In some embodiments, the exterior of the secondary battery may be a pouch, for example, a bag-shaped pouch. The material of the pouch may be plastic, and for example, it may include one or more of polypropylene (PP), polybutylene terephthalate (PBT), polybutylene succinate (PBS), etc. The exterior of the secondary battery may also be a rigid case, such as an aluminum case.

[0200] In some embodiments, the positive electrode plate, negative electrode plate, and separator can be manufactured into an electrode assembly by a winding process or a lamination process.

[0201] This application is not particularly limited to the shape of the secondary battery, and it may be cylindrical, square, or any other arbitrary shape. FIG. 1 shows a secondary battery 5 with a square structure as an example.

[0202] [Battery Module, Battery Pack, and Power Consumption Device] The fourth aspect of this application provides a battery module, which includes the secondary battery described in the third aspect of this application.

[0203] In some embodiments, the secondary battery according to this application may be assembled as a battery module, and the number of secondary batteries included in the battery module may be plural, and the specific number can be adjusted according to the application and capacity of the battery module.

[0204] FIG. 2 shows a battery module 4 as an example. Referring to FIG. 2, in the battery module 4, a plurality of secondary batteries 5 may be arranged in sequence along the longitudinal direction of the battery module 4. Of course, they may be arranged in any other arbitrary manner. Furthermore, these plurality of secondary batteries 5 may be fixed with fasteners.

[0205] Optionally, the battery module 4 may further include a case having an accommodation space, and a plurality of secondary batteries 5 are accommodated in this accommodation space.

[0206] A fifth aspect of this application provides a battery pack comprising at least one of the secondary battery described in the third aspect of this application or the battery module described in the fourth aspect of this application.

[0207] In some embodiments, battery modules assembled from secondary batteries may be assembled as a battery pack, and the number of battery modules included in the battery pack may be adjusted according to the application and capacity of the battery pack.

[0208] Figures 3 and 4 show an example of a battery pack 1. Referring to Figures 3 and 4, the battery pack 1 may include a battery box and a plurality of battery modules 4 installed in the battery box. The battery box includes an upper housing 2 and a lower housing 3, and the upper housing 2 can be covered by the lower housing 3 to form a sealed space for housing the battery modules 4. The plurality of battery modules 4 may be arranged in the battery box in any manner.

[0209] A sixth aspect of this application provides a power consumption device comprising at least one of a secondary battery according to a third aspect of this application, a battery module according to a fourth aspect of this application, or a battery pack according to a fifth aspect of this application, which provides a power source to the power consumption device. The power consumption device may, but is not limited to, mobile devices (e.g., mobile phones, laptop computers, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0210] The aforementioned power consumption device can select a secondary battery, battery module, or battery pack depending on its usage needs.

[0211] Figure 5 shows an example of a power consumption device. This power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the demand for high power and high energy density of the secondary battery in this power consumption device, a battery pack or battery module can be used.

[0212] Other examples of power-consuming devices include mobile phones, tablet computers, and laptop computers. These power-consuming devices generally require a thin design and can employ rechargeable batteries as their power source.

[0213] Examples The following describes embodiments of this application. The embodiments described below are illustrative and are used solely for interpreting this application and should not be construed as limitations thereon. Unless otherwise specified in the embodiments, specific techniques or conditions are described in the art literature or in accordance with the specifications of the conditions or products. Unless otherwise specified, the reagents or instruments used are all common products available on the market.

[0214] Example 1 Production of the first organic particle (P1) At room temperature, the required monomers were uniformly stirred and mixed in the following weight percentages: 25% by weight of 2-hydroxyethyl acrylate, 20% by weight of n-butyl acrylate, 5% by weight of methyl methacrylate, 5% by weight of trimethylolpropane triacrylate, 20% by weight of acrylonitrile, and 25% by weight of acrylamide. 2 kg of the mixed monomers, 60 g of sodium lauryl sulfate emulsifier, 20 g of ammonium persulfate initiator, and 2.40 kg of deionized water were added to a 10 L four-necked flask containing a mechanical stirrer, thermometer, and condenser. The mixture was emulsified by stirring at a rotation speed of 1600 rpm for 30 minutes. Then, the temperature was raised to 75°C under nitrogen gas protection and the mixture was reacted for 4 hours. After adjusting the pH to 6.5 with a 1 wt% NaOH aqueous solution, the temperature was immediately cooled to below 40°C and the mixture was discharged, yielding an organic polymer in emulsion form with a solid content of approximately 45%.

[0215] The above organic polymer and silicon dioxide were added to an appropriate amount of deionized water in a dry weight-to-mass ratio of 9:1, stirred for 1 hour to mix thoroughly, and then spray-dried to remove the solvent and obtain a powder. The resulting powder was then ground and polished to obtain a Dv50 particle size of 8 μm, a particle size distribution (Dv90-Dv10) / Dv50 of 1.76, a DSC vitrification transfer temperature of 60°C, and a weight-average molecular weight of approximately 600 × 10⁻¹⁶. 3 We obtained the first organic particles in g / mol.

[0216] Manufacturing of pressure-sensitive adhesives The pressure-sensitive adhesive comprises an organic polymer and a plasticizer, where the organic polymer is a copolymer of 30 wt% isobutyl acrylate + 25 wt% isooctyl acrylate + 5 wt% 2-hydroxypropyl methacrylate + 15 wt% styrene + 22 wt% acrylonitrile + 3 wt% polyvinyl alcohol, and the plasticizer is glycerol, with a graft rate of 8 wt%. It can be manufactured by referring to the patent document with PCT application number PCT / CN2021 / 143069.

[0217] Manufacturing of separators 1) A polyethylene microporous membrane with a thickness of approximately 9 μm, a hole diameter of approximately 50 nm, and a porosity of approximately 38% (purchased from Shanghai Enjie Co., Ltd.) is used as the separator substrate. 2) Add 3.3 kg of pressure-sensitive adhesive (containing an organic polymer and a plasticizer, with a vitrification transfer temperature of approximately 10°C, a volume-average particle size Dv50 of approximately 1.1 μm, and a mass ratio of 5:1 (where approximately 8 wt% of the plasticizer is grafted onto the organic polymer relative to the weight of the plasticizer), where the organic polymer is a copolymer of 30 wt% isobutyl acrylate + 25 wt% isooctyl acrylate + 5 wt% 2-hydroxypropyl methacrylate + 15 wt% styrene + 22 wt% acrylonitrile + 3 wt% polyvinyl alcohol, and the plasticizer is glycerol) to 23.6 kg of deionized water to obtain the first polymer solution. 3) Add an appropriate amount of the first organic particles (P1, 25 wt% hydroxyethyl acrylate + 20 wt% n-butyl acrylate + 5 wt% methyl methacrylate + 5 wt% trimethylolpropane triacrylate + 20 wt% acrylonitrile + 25 wt% acrylamide, Dv50 particle size is 6 μm, (Dv90-Dv10) / Dv50 is 1.76, vitrification transfer temperature is 60°C, weight-average molecular weight is approximately 600 × 10⁻¹⁶ 3 Add 18 g of dispersant (BYK-22136, BYK Chemical, brand name 22136) and mix thoroughly to form a second polymer solution, wherein the mass ratio of the first organic particles to the pressure-sensitive adhesive, based on dry weight, is 90:10. 4) The second polymer solution obtained in step 3) is prepared as an aqueous coating slurry and applied to the two surfaces of the separator substrate by spin spraying. After drying, 32 locations are taken, and the change in gram weight of the separator per unit area before and after spin spraying is measured at each location. The average value is taken, and the surface density ρ of the separator coating is determined to be 0.97 g / m². 2 The resulting separator comprises a separator substrate and pressure-sensitive coatings applied to two surfaces of the separator substrate, the thickness of which is approximately 3 μm, and contains a pressure-sensitive adhesive and a first organic particle with a mass ratio of 90:10 based on dry weight, wherein the pressure-sensitive adhesive contains an organic polymer and a plasticizer with a mass ratio of 5:1 (where approximately 8 wt% of the plasticizer is grafted onto the organic polymer relative to the weight of the plasticizer).

[0218] Manufacturing of rechargeable batteries The active material is LiNi 1 / 3 Mn 1 / 3 Co 1 / 3O2, acetylene black as a conductive agent, and polyvinylidene fluoride (PVDF, weight average molecular weight 1,200,000 g / mol) as an adhesive were stirred and mixed thoroughly in a solvent of N-methylpyrrolidone in a weight ratio of 94:3:3. After that, a positive electrode slurry was obtained. This slurry was coated on an aluminum (Al) foil, dried, and cold-pressed to obtain a positive electrode plate. The loading amount of the positive electrode active material on the positive electrode plate was 0.32 g / 1540.25 mm 2 and the density was 3.45 g / cm 3 .

[0219] Artificial graphite as an active material, acetylene black as a conductive agent, styrene-butadiene rubber (SBR) as an adhesive, and sodium carboxymethyl cellulose (CMC) as a thickener were stirred and mixed thoroughly in deionized water as a solvent in a weight ratio of 95:2:2:1. After that, a negative electrode slurry was obtained. This slurry was coated on a copper (Cu) foil, dried, and cold-pressed to obtain a negative electrode plate. The loading amount of graphite on the negative electrode plate was 0.18 g / 1540.25 mm 2 and the density was 1.65 g / cm 3 .

[0220] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 3:5:2, and LiPF6 was uniformly dissolved in the above solution to obtain an electrolyte solution. In this electrolyte solution, the concentration of LiPF6 was 1 mol / L.

[0221] The separator produced in each example or comparative example was used as a separator for a secondary battery.

[0222] The positive electrode plate, separator, and negative electrode plate were laminated in order so that the separator was located in the middle of the positive and negative electrodes to play a role of isolation, and then wound back to obtain a bare battery core. The bare battery core was placed in an outer package, and the electrolyte solution was injected and packaged to obtain a secondary battery. It should be noted that when the separator coating is on one side, the coating surface faces the cathode (i.e., the positive electrode plate) side.

[0223] Test Method 1. Volume-average particle size test The method was based on the GB / T 19077-2016 / ISO 13320:2009 standard for particle size distribution laser diffraction. Tests were performed using a laser particle size analyzer (Marvin 3000, MasterSizer 3000), with a helium-neon red light source as the primary light source. A clean small beaker was prepared, containing 1 g of the sample to be measured. A drop of surfactant was added to promote dispersion, followed by 20 ml of deionized water (ensuring a sample concentration of 8-12% light shielding). The sample was then ultrasonically treated at 53 kHz / 120 W for 5 minutes to ensure complete dispersion. After turning on the laser particle size analyzer and cleaning the optical path system, the background was automatically tested. The already ultrasonically treated solution to be measured was stirred to ensure uniform dispersion, placed in the sample pool as needed, and particle size measurement was initiated. The measurement results could be read from the instrument.

[0224] 2. Vitrification transfer temperature Measurements may be taken using methods commonly used in this field, for example, by differential scanning calorimetry as described in GB / T 19466.2. The heating rate was 10°C / min, and the atmosphere was air.

[0225] 3. Graft rate test of plasticizers in pressure-sensitive adhesives Detection may also be performed using infrared testing methods. Specifically, Fourier infrared spectrograms are obtained from tests of organic polymers, plasticizers, and pressure-sensitive adhesives, and the pressure-sensitive adhesive is detected at 1500-1700 cm⁻¹. -1 A different peak appears at this position compared to the organic polymer and the plasticizer alone. This peak represents the grafted plasticizer, and the area under the peak represents the amount of grafted plasticizer. The grafting rate of the plasticizer (peak area corresponding to the characteristic peak of the grafted plasticizer / peak area of ​​the plasticizer % representing 100%) can be calculated from this.

[0226] 4. Evaluation of the adhesive performance of the separator The test process is as follows:

[0227] 1. A 300mm long x 100mm wide separator and the positive and negative electrode plates manufactured as described above were selected.

[0228] 2. The top and bottom surfaces of the separator were wrapped in paper, and a 54.2mm x 72.5mm sample was cut out using a knife die and a press.

[0229] 3. The cut-out separator sample and the positive or negative electrode plate were neatly stacked, taking care to ensure the separator was on top (so that the coating would face the positive electrode plate when one side was coated). A 130mm x 130mm sheet of Teflon (registered trademark: teflon) was placed on the top and bottom surfaces respectively, the stacked sample was placed in the middle of a 200mm x 200mm piece of cardboard, and then another 150mm x 160mm piece of cardboard was placed on top.

[0230] 4. The stacked samples were placed in a flat plate press and the pressure was adjusted. The flat plate press pressure was set to 350KG ± 10KG (the contact area was approximately 54.2mm × 72.5mm, and the actual pressure after conversion was approximately 0.87MPa). The temperature was set to T=25℃ and the time to 15 seconds, and the samples were pressed.

[0231] 5. The sample, which had been heat-pressed using a knife die and press, was cut into small pieces measuring 72.5 mm x 15 mm.

[0232] 6. One side of the electrode plate was attached to the steel plate with double-sided tape and secured, and a separator was attached to the other side. A 15mm wide A4 sheet of paper was then attached to the separator using double-sided tape, completing the production of the test sample.

[0233] 7. The Gotech tensile machine was turned on, and the parameters were set sequentially to adhesive strength test, speed 50 mm / min, and starting jig pitch 40 mm.

[0234] 8. The test sample was placed between the fixtures, with the end of the steel plate secured to the lower collet and the A4 paper secured to the upper collet. The upper and lower end collets were clamped by the fixtures.

[0235] 9. Click the operating interface for stretching on the computer desktop, clear the force, displacement, etc., and then click "Start" to perform a pre-stretch of approximately 5 mm. After the pre-stretch, clear the force, displacement, etc. again and start the test. During the test, a steel plate was fixed to secure the electrode plates, and the tensile machine pulled an A4 sheet of paper upwards to separate the separator from the electrode plates. Once the test was complete, the complete data was exported and saved.

[0236] 10. Each group measured at least five test samples, and if the curve repeatability of the adhesion strength test of the five test samples was relatively good, the next group was tested. Otherwise, the test had to be repeated until the repeatability of the five test samples was relatively good.

[0237] 11. After the test was completed, an adhesive strength (N / m)-displacement curve was created, and the average value of the 100th to 300th data points was used as the adhesive force, and the measured adhesive force was defined as F0.

[0238] 12. Steps 1-11 were repeated, but in step 4, the pressure was changed to 850 kg ± 10 kg (the actual pressure after conversion is equivalent to approximately 2.24 MPa), and the temperature T was changed to 25°C. The resulting adhesive strength was denoted as F1.

[0239] 13. Steps 1-11 were repeated, but in step 4, the pressure was changed to 850 kg ± 10 kg (the actual pressure after conversion is equivalent to approximately 2.24 MPa), and the temperature T was changed to 95°C. The resulting adhesive strength was denoted as F2.

[0240] 5. Evaluation of the resistive performance of the separator The test process is as follows:

[0241] (1) Preparation of separators: Cut each separator to be measured into samples of the same size (45.3 mm * 33.7 mm), bake the samples in a 60°C environment for at least 4 hours, and then quickly transfer them to a 25°C Grade 100 cleaning glove box to set aside. (2) Manufacturing of symmetrical battery containment pocket bags (symmetrical battery containment aluminum plastic bags (aluminum plastic bags are a general-purpose product made of polypropylene and aluminum foil for pouch cells)): Blank symmetrical batteries assembled with Cu Foil vs. Cu Foil (copper foil vs. copper foil) as current collectors were adopted. The containment of these pocket bags was achieved by green adhesive intermediate punching. Before use, the pocket bags should be baked in a 60°C environment for at least 4 hours and then quickly transferred to a 25°C Grade 100 cleaning glove box as described in (1) above for storage. (3) Assembly of symmetrical batteries: Using the negative electrode plate as the electrode, five sets of symmetrical battery samples, each with a different number of separator layers (1, 2, 3, 4, and 5 layers), are assembled in their original positions in the glove box described in (1) above. Each set of samples consists of five parallel samples. The Pocket bags are side-sealed using a simple packaging machine, and liquid (300 μL) is injected using a pipette gun (electrolyte, same composition as battery electrolyte), and the bottles are sealed. (4) Attaching the fixture to the assembled symmetrical battery: Place the assembled symmetrical battery in the glove box described in (1) above overnight so that the electrolyte can sufficiently permeate the separator. The next day, attach the metal fixture and control the pressure of the fixture to 0.7 MPa. (5) Measurement of electrochemical impedance spectroscopy (EIS): Before measurement, symmetrical batteries with different numbers of separator layers are placed in a high-temperature chamber and maintained at a constant temperature of 25°C for half an hour, and the EIS is measured at the set temperature (25°C) (for low temperatures (e.g., -25°C to 0°C), the constant temperature period can be extended, for example, by about 2 hours). (6) A French Bio-Logic VMP3 electrochemical operating station was used, with a voltage < 5V, current < 400mA, and current accuracy: 0.1% * 100μA. During measurement, the EIS measurement conditions were set to voltage frequency 1MHz-1kHz, the disturbance voltage was set to 5MV, and the jig pressure was controlled to 0.7MPa.

[0242] (7) A scattergram was created for the real part of the EIS data relative to the imaginary part, and the EIS plot obtained by plotting parallel samples with different numbers of layers and the same number of layers on a single graph was compared with the raw EIS data.

[0243] (8) Points other than those in the first quadrant were removed from the EIS diagram obtained in (7) above to obtain a new EIS diagram. Linear fitting of the plots in the first quadrant was performed on the new EIS diagram to obtain a related equation, and setting y=0 gave the x value, which is the resistance value of the required separator in the electrolyte. By analogy, linear fitting of the measured EIS data can be performed to obtain the resistance values ​​between parallel samples with different numbers of layers. Let R be the parallel sample of five resistance values.

[0244] 6. Performance evaluation of secondary batteries Cycle performance test: Five batteries were taken from each set of manufactured rechargeable batteries, and the charge and discharge processes were repeatedly performed according to the following steps to calculate the cycle capacity retention rate of the rechargeable batteries under 25°C or 45°C conditions.

[0245] In a 25°C environment, the first charge-discharge cycle was performed. Constant current and constant voltage charging was carried out with a charging current of 0.7C (i.e., the current value that completely releases the theoretical capacity within 2 hours) until the upper voltage limit reached 4.4V. Then, constant current discharge was carried out with a discharge current of 0.5C until the final voltage reached 3V. The discharge capacity of the first cycle was recorded. Subsequently, 1000 charge-discharge cycles were performed, and the discharge capacity of the 1000th cycle was recorded. The cycle capacity retention rate is calculated as (discharge capacity of the 1000th cycle / discharge capacity of the first cycle) × 100%.

[0246] In a 45°C environment, the first charge-discharge cycle was performed. Constant current and constant voltage charging was carried out with a charging current of 0.7C (i.e., the current value that completely releases the theoretical capacity within 2 hours) until the upper voltage limit reached 4.4V. Then, constant current discharge was carried out with a discharge current of 0.5C until the final voltage reached 3V. The discharge capacity of the first cycle was recorded. Subsequently, 1000 charge-discharge cycles were performed, and the discharge capacity of the 1000th cycle was recorded. The cycle capacity retention rate is calculated as (discharge capacity of the 1000th cycle / discharge capacity of the 1st cycle) × 100%.

[0247] Examples 2-3 Example 2 is the same as Example 1, except that the ratio of the first organic particles (Dv90-Dv10) / Dv50 in the separator coating is different. Specifically, the ratio of the first organic particles (Dv90-Dv10) / Dv50 in the separator manufactured in Example 2 is 2.

[0248] The first organic particle (Dv90-Dv10) / Dv50 of the separator produced in Example 3 is 2.5.

[0249] Comparative Example 1 The procedure is the same as in Example 1, except that the ratio of the first organic particles (Dv90-Dv10) / Dv50 in the separator coating is 3.5.

[0250] Examples 4-8 Examples 4-8 are the same as Example 1, except that the first organic particles used are different and have different vitrification transfer temperatures. Specifically, the vitrification transfer temperatures of the first organic particles used in Examples 4-8 are 20°C, 30°C, 40°C, 80°C, and 100°C, respectively.

[0251] Comparative Example 2-3 This is the same as Example 1, except that the first organic particles P5 and P11, which have vitrification transfer temperatures of 10°C and 110°C respectively, were used.

[0252] Examples 9-13 The surface density ρ / R of the separator coating is 0.52 g·m². -2 ·Ω-1 , 0.65g·m -2 ·Ω -1 , 0.83g·m -2 ·Ω -1 , 0.96g·m -2 ·Ω -1 and 0.98g·m -2 ·Ω -1 Except for the above, it is the same as Example 1.

[0253] Comparative Example 4-6 The surface density ρ / R of the separator coating is 0.26 g·m². -2 ·Ω -1 , 0.29g·m -2 ·Ω -1 and 0.41 g·m -2 ·Ω -1 Except for the above, it is the same as Example 1.

[0254] Examples 14-15 This is the same as Example 1, except that the first organic particles used are P12 and P13, respectively.

[0255] Example 16 Manufacturing of separators 1) A polyethylene microporous membrane with a thickness of approximately 9 μm, a hole diameter of approximately 50 nm, and a porosity of approximately 38% (purchased from Shanghai Enjie Co., Ltd.) is used as the separator substrate. 2) Add 21 kg of the first organic particles P1 to 140 kg of deionized water, mix uniformly, and then form the first polymer solution. 3) Add an aqueous emulsion of 23.5 kg of pressure-sensitive adhesive (containing an organic polymer and a plasticizer, with a vitrification transfer temperature of approximately 10°C, a volume-average particle size Dv50 of approximately 1.1 μm, and a mass ratio of 5:1 (where approximately 8 wt% of the plasticizer is grafted onto the organic polymer relative to the weight of the plasticizer, and where the organic polymer is a copolymer of 30 wt% isobutyl acrylate + 25 wt% isooctyl acrylate + 5 wt% hydroxypropyl methacrylate + 15 wt% styrene + 22 wt% acrylonitrile + 3 wt% polyvinyl alcohol, and the plasticizer is glycerol) to the first polymer solution obtained in step 2), mix uniformly to obtain a second polymer solution. 4) Add an appropriate amount of second organic particles (polyvinylidene fluoride, weight-average molecular weight 500,000 g / mol) to the second polymer solution obtained in step 3) above, and mix uniformly to obtain a third polymer solution, in which the mass ratio of all organic particles (including the first and second organic particles with a dry weight mass ratio of 90:10) to the pressure-sensitive adhesive is 85:15. 5) The third polymer solution obtained in step 4) was prepared as an aqueous coating slurry and coated onto one surface of the separator substrate by spin spraying. After drying, a separator was obtained. The manufactured separator comprises a separator substrate and a coating applied to one surface of the separator substrate. The thickness of the coating is approximately 3 μm and comprises organic particles with a mass ratio of 85:15 based on dry weight (including first and second organic particles with a mass ratio of 90:10 based on dry weight) and a pressure-sensitive adhesive. This pressure-sensitive adhesive comprises an organic polymer and a plasticizer with a mass ratio of 5:1 (where approximately 8 wt% of the plasticizer is grafted onto the organic polymer relative to the weight of the plasticizer). The coating density is 0.97 g / m². 2 As shown in Figure 6, the topography of the separator coating manufactured in this embodiment is shown.

[0256] Examples 17-19 The above coating is the same as in Example 16, except that the mass ratios of the first organic particles and the second organic particles, based on their dry weight, are 70:30, 50:50, and 40:60, respectively.

[0257] Comparative Example 7 This is the same as Example 16, except that the first organic particle is not used.

[0258] The composition of the first organic particles used in the examples and comparative examples is shown in Table 1 below.

[0259] The adhesive performance, resistance, and cycle performance of the secondary batteries produced using the separators manufactured in Examples 1-19 and Comparative Example 1-7 were evaluated, and the results are shown in Table 2 below.

[0260] [Table 1] JPEG0007871380000002.jpg254157JPEG0007871380000003.jpg254111

[0261] [Table 2] JPEG0007871380000005.jpg249148

[0262] As can be seen from the results in Tables 1 and 2, by combining organic particles with a pressure-sensitive adhesive made from organic polymers and plasticizers during the manufacturing of the separator, high adhesive performance and ion conductivity can be effectively imparted to the separator at room temperature. Specifically, at room temperature, the resistance of the manufactured separators is 1.89 Ω or less. At room temperature and under pressure of ≥2 MPa, the adhesive strength to the positive electrode is 0.15 N / m or more, particularly 0.4 N / m or more, but under pressure of ≤1 MPa, the adhesive strength to the electrode is 0.08 N / m or less. Therefore, the manufactured separators can avoid excessive adhesion between layers during the winding and storage processes, and at the same time, when manufacturing battery cores using these separators, the electrode plates and separators can be tightly bonded at room temperature. On the one hand, misalignment between the electrode plate and the separator can occur, leading to the discarding of the battery core and thus avoiding impacts on battery core performance and safety risks. On the other hand, the tunnel furnace and the second combined process in the conventional battery core production process can be omitted, further saving production space and time, reducing energy consumption, and significantly increasing the production capacity of battery cores. At the same time, the shaping performance, safety performance, and dynamic performance of the battery core can be improved. Furthermore, the separator of this application exhibits a good matching relationship between the adhesive strengths F1 and F2 at room temperature and high temperature.

[0263] Examples 20-21 This is the same as Example 16, except that the mass ratio of organic particles (including the first organic particles and the second organic particles) to the pressure-sensitive adhesive in the coating, and the mass ratio of the first organic particles to the second organic particles based on their dry weight are different. Specifically, In the separator coating produced in Example 20, the dry weight-based mass ratio of organic particles to pressure-sensitive adhesive was 85:15, where the dry weight-based mass ratio of the first organic particle to the second organic particle was 75:10.

[0264] In the pressure-sensitive coating of the separator manufactured in Example 21, the dry weight-based mass ratio of organic particles to pressure-sensitive adhesive was 90:10, where the dry weight-based mass ratio of the first organic particle to the second organic particle was 65:25.

[0265] The experimental results for Examples 20-21 are shown in Table 3.

[0266] [Table 3]

[0267] As can be seen from Table 3, by adjusting the mass ratio of the first organic particles, the second organic particles, and the pressure-sensitive adhesive, the resistance of the separator can be further reduced while avoiding a significant deterioration in the cycle performance of the secondary battery.

[0268] Examples 22-24 Example 22 is the same as Example 1, except that the graft ratio of the plasticizer in the pressure-sensitive adhesive used is different. Specifically, the graft ratio of the plasticizer in the pressure-sensitive adhesive used in Example 22 is 5 wt%.

[0269] The graft ratio of plasticizer in the pressure-sensitive adhesive used in Example 23 was 3 wt%.

[0270] The graft rate of plasticizer in the pressure-sensitive adhesive used in Example 24 was 0 wt%, meaning that no plasticizer was grafted.

[0271] The experimental results for Examples 22-24 are shown in Table 4.

[0272] [Table 4]

[0273] As can be seen from Table 4, by adjusting the grafting rate of the plasticizer, the resistance of the separator can be further reduced, improving the adhesion performance of the separator and the corresponding cycle performance of the battery.

[0274] Examples 25-29 Example 25 is the same as Example 1, except that the particle size of the first organic particles and the thickness of the coating are different. Specifically, the Dv50 particle size of the first organic particles used in Example 25 is approximately 3 μm, and the coating thickness is approximately 0.8 μm.

[0275] The Dv50 particle size of the first organic particles used in Example 26 is approximately 5 μm, and the coating thickness is approximately 2 μm.

[0276] The Dv50 particle size of the first organic particles used in Example 27 is approximately 20 μm, and the coating thickness is approximately 15 μm.

[0277] The Dv50 particle size of the first organic particle used in Example 28 is approximately 30 μm, and the coating thickness is approximately 20 μm.

[0278] The Dv50 particle size of the first organic particle used in Example 29 is approximately 36 μm, and the coating thickness is approximately 22 μm.

[0279] Examples 30-36 Example 30 is the same as Example 1, except for the difference in the particle size of the pressure-sensitive adhesive. Specifically, the Dv50 particle size of the pressure-sensitive adhesive used in Example 30 is approximately 0.3 μm.

[0280] The Dv50 particle size of the pressure-sensitive adhesive used in Example 31 is approximately 0.5 μm.

[0281] The Dv50 particle size of the pressure-sensitive adhesive used in Example 32 is approximately 0.8 μm.

[0282] The Dv50 particle size of the pressure-sensitive adhesive used in Example 33 is approximately 1.0 μm.

[0283] The Dv50 particle size of the pressure-sensitive adhesive used in Example 34 is approximately 2.0 μm.

[0284] The Dv50 particle size of the pressure-sensitive adhesive used in Example 35 is approximately 3.0 μm.

[0285] The Dv50 particle size of the pressure-sensitive adhesive used in Example 36 is approximately 3.5 μm.

[0286] Examples 37-40 Example 37 is the same as Example 20, except that the particle size of the second organic particles used is different and the thickness of the manufactured coating is different. Specifically, the Dv50 particle size of the second organic particles used in Example 37 is approximately 2 μm, and the coating thickness is approximately 3 μm.

[0287] The Dv50 particle size of the second organic particle used in Example 38 was approximately 8 μm, and the coating thickness was approximately 4 μm.

[0288] The Dv50 particle size of the second organic particle used in Example 39 was approximately 10 μm, and the coating thickness was approximately 6 μm.

[0289] The Dv50 particle size of the second organic particle used in Example 40 was approximately 12 μm, and the coating thickness was approximately 10 μm.

[0290] The experimental results for Examples 25-40 are shown in Table 5.

[0291] [Table 5]

[0292] As can be seen from Table 5, by adjusting the Dv50 particle size of the first organic particles, the pressure-sensitive adhesive, and the second organic particles in the coating, as well as the coating thickness, the resistance of the separator can be further reduced, improving the adhesion performance of the separator and the corresponding battery cycle performance.

[0293] It should be noted that this application is not limited to the embodiments described above. The embodiments described above are illustrative, and any embodiments that have substantially the same configuration as the technical idea and produce the same effects within the scope of the technical proposal of this application are included within the scope of the technical proposal of this application. Furthermore, other methods that are constructed by adding various modifications to the embodiments that a person skilled in the art could conceive of, and by combining some of the components of the embodiments, are also included within the scope of this application, without departing from the spirit of this application. [Explanation of symbols]

[0294] The explanation of the symbols is as follows: 1. Battery pack, 2. Upper casing, 3. Lower casing, 4. Battery module, 5. Rechargeable battery

Claims

1. A separator, Substrate and, A coating applied to at least one surface of the substrate, Includes, The coating comprises 40-90 wt% of primary organic particles and 2-15 wt% of a pressure-sensitive adhesive. Here, the first organic particles comprise an organic polymer and an inorganic substance, and the pressure-sensitive adhesive comprises an organic polymer and a plasticizer. The volume-average particle size of the first organic particle satisfies (Dv90 - Dv10) / Dv50 ≤ 2.5, and the vitrification transfer temperature of the first organic particle is 20-100°C. The separator is 0.5 g / m². －２ ・Ω －１ ≦ρ / R≦0.9g・m －２ ・Ω －１ The following conditions are met, where ρ represents the surface density of the coating on the substrate, and R represents the resistance of the separator at 25°C. The organic polymer in the first organic particle is at least, A first polymerizable monomer having at least one ester bond, A second polymerizable monomer having at least one cyanide bond, It is polymerized with a third polymerizable monomer having at least one amide bond, The inorganic substance in the first organic particles is selected from one or more of silicon, aluminum, calcium, zinc, magnesium oxides and sodium sulfate, sodium benzoate, and calcium carbonate, and the inorganic substance content in the first organic particles is 1-30% based on the total dry weight of the first organic particles. In the pressure-sensitive adhesive, the organic polymer comprises a copolymer obtained by copolymerizing a mixture of at least one of the following first monomer group, at least one of the second monomer group, at least one of the third monomer group, and at least one of the reactive dispersants. The first group of monomers includes acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylolacrylamide, acrylamide, styrene, and acrylonitrile. The second monomer group includes isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, ethyleneurea ethyl methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and acrylic methacrylate. The third monomer group includes 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, γ-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethacrylamide, diacetoneacrylamide (DAAM), acetate acetate methacrylate (AAEM), divinylbenzene, and epoxy resins with an epoxy value of 0.35-0.50, and The reactive dispersant comprises polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, and polyethylene glycol. The plasticizer is glycerol C ４ -C １０ alkyl diether or monoether, glycerol C ４ -C １０ carboxylic acid monoester or diester, propylene glycol C ４ -C １０ The separator is selected from one or more of alkyl monoether or glycerol.

2. The separator according to claim 1, wherein the coating further comprises 0-50 wt% of second organic particles, the volume average particle size Dv50 of the second organic particles being 2-20 μm, and the melting point of the second organic particles being 130-160°C.

3. The separator according to claim 1, wherein the volume-average particle size Dv50 of the first organic particle is 3-36 μm.

4. The separator according to claim 1, wherein the vitrification transfer temperature of the first organic particles is 20-100°C.

5. The weight-average molecular weight of the organic polymer in the first organic particle is 500 × 10 ３ g / mol-1000×10 ３ The separator according to claim 1, wherein the concentration is g / mol.

6. The first polymerizable monomer is one or more of the following: methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, vinyl acetate, trifluoroethyl methacrylate, glycidyl methacrylate, or trimethylolpropane triacrylate. The second polymerizable monomer is one or more of acrylonitrile, methacrylonitrile, and ethacrylonitrile. The separator according to claim 1, wherein the third polymerizable monomer is one or more of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide.

7. The separator according to claim 1, wherein the weight ratio of the first polymerizable monomer, the second polymerizable monomer, and the third polymerizable monomer is 1:0-0.8:0.05-0.

75.

8. The separator according to any one of claims 1 to 7, wherein the content of the organic polymer in the first organic particles is 50-99.9% based on the total dry weight of the first organic particles.

9. The separator according to any one of claims 1 to 7, wherein the weight ratio of the organic polymer to the inorganic material in the first organic particle is 99:1 to 1:

1.

10. Based on the total weight of the organic polymer in the first organic particle, The content of the first polymerizable monomer is 35-80% by weight. The content of the second polymerizable monomer is 0-30% by weight, and The separator according to claim 3, wherein the content of the third polymerizable monomer is 5-40% by weight.

11. The separator according to any one of claims 1 to 7, wherein the inorganic substance in the first organic particle is one or more of silicon dioxide, silica sol, aluminum oxide, zinc oxide, magnesium oxide, and sodium benzoate.

12. The separator according to any one of claims 1 to 7, wherein the surface of the first organic particles is uneven and has a uniform distribution of inorganic oxide clusters with a particle size of 10-200 nm.

13. The separator according to any one of claims 1 to 7, wherein the mass ratio of the organic polymer to the plasticizer contained in the pressure-sensitive adhesive is (4-25):

1.

14. The separator according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive has a core-shell structure, and both the core and the housing of the core-shell structure contain an organic polymer and a plasticizer, where the mass ratio of the organic polymer to the plasticizer in the core is (3-4):1, and the mass ratio of the organic polymer to the plasticizer in the housing structure is (7-9):

1.

15. The separator according to any one of claims 1 to 7, wherein a portion of the plasticizer in the pressure-sensitive adhesive is grafted onto the organic polymer.

16. The separator according to claim 15, wherein, in the pressure-sensitive adhesive, at least 5 wt% of the plasticizer is grafted onto the organic polymer, based on the weight of the plasticizer.

17. The separator according to any one of claims 1 to 7, wherein the volume average particle size Dv50 of the pressure-sensitive adhesive is 0.3 to 3.5 μm.

18. The separator according to any one of claims 1 to 7, wherein the vitrification transfer temperature of the pressure-sensitive adhesive is -50°C to 100°C.

19. The separator according to any one of claims 1 to 7, wherein the average thickness of the coating is 0.8-22 μm.

20. The separator according to claim 2, wherein the second organic particle is a polymer of one or more monomers including a halogen, a phenyl group, an epoxy group, a cyano group, an ester group, and an amide group.

21. The separator according to claim 2, wherein the second organic particle is selected from at least one of the following: a homopolymer or copolymer of fluorine-containing alkenyl monomer units, a homopolymer or copolymer of olefin-based monomer units, a homopolymer or copolymer of unsaturated nitrile-based monomer units, a homopolymer or copolymer of alkylene oxide-based monomer units, or a dipolymer, homopolymer, or copolymer of monosaccharide monomer units.

22. The separator according to claim 2, wherein the second organic particle is selected from at least one of polyperfluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polystyrene-co-methyl methacrylate, polystyrene-co-butyl acrylate, styrene-butyl acrylate-isooctyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyethylene-co-vinyl acetate, polyimide, polyethylene oxide, cellulose acetate, cellulose butyrate acetate, cellulose propionate acetate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethylcellulose, and cyanoethylsucrose.

23. The weight-average molecular weight of the second organic particle is 400 × 10 ３ g / mol-1000×10 ３ The separator according to claim 2, wherein the concentration is g / mol.

24. The separator according to any one of claims 1 to 7, wherein the porosity of the substrate is 10-95%.

25. The separator according to any one of claims 1 to 7, wherein the hole diameter of the substrate is 20-60 nm.

26. The separator according to any one of claims 1 to 7, wherein the thickness of the substrate is 3-12 μm.

27. The separator according to any one of claims 1 to 7, wherein the substrate is a film or nonwoven fabric selected from one or more of polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cycloolefin copolymer, polyphenylene sulfide, and polyethylene naphthalene.

28. The separator according to claim 2, wherein the mass ratio of the first organic particle to the second organic particle is 10-100:0-90.

29. The separator according to claim 2, wherein the ratio of the sum of the masses of the first organic particles and the second organic particles to the mass of the pressure-sensitive adhesive is 20-92:8-20.

30. A method for manufacturing a separator according to any one of claims 1 to 7, Step S1 involves adding the first organic particles and a dispersant to the solvent to form the first polymer solution, Step S2 involves adding a pressure-sensitive adhesive to the first polymer solution obtained in step S1 and mixing thoroughly to form a second polymer solution, Step S3 involves applying the second polymer solution obtained in step S2 to at least one surface of the substrate, drying it, and then obtaining a separator. Includes, The separator comprises a substrate and a coating applied to at least one surface of the substrate. The coating comprises 40-90 wt% of primary organic particles and 2-15 wt% of a pressure-sensitive adhesive. The first organic particles comprise an organic polymer and an inorganic substance, the pressure-sensitive adhesive comprises an organic polymer and a plasticizer, the volume-average particle size of the first organic particles satisfies (Dv90 - Dv10) / Dv50 ≤ 2.5, the vitrification transfer temperature of the first organic particles is 20-100°C, and the separator is 0.1 g·m －２ ・Ω －１ ≦ρ / R≦1.0g・m －２ ・Ω －１ A method for manufacturing a separator, wherein the following conditions are met, where ρ represents the surface density of the coating on the substrate and R represents the resistance of the separator at 25°C.

31. A method for manufacturing a separator according to any one of claims 1 to 7, Step S1 involves adding the first organic particles and a dispersant to the solvent to form the first polymer solution, Step S2 involves adding a pressure-sensitive adhesive to the first polymer solution obtained in step S1 and mixing thoroughly to form a second polymer solution, Step S3 involves adding a second organic particle to the second polymer solution obtained in step S2 and mixing it thoroughly to form a third polymer solution. Step S4 involves applying the third polymer solution obtained in step S3 to at least one surface of the substrate, drying it, and then obtaining a separator. Includes, The separator comprises a substrate and a coating applied to at least one surface of the substrate. The coating comprises 40-90 wt% of a first organic particle, 2-15 wt% of a pressure-sensitive adhesive, and 0-50 wt% of a second organic particle. The first organic particles comprise an organic polymer and an inorganic substance, the pressure-sensitive adhesive comprises an organic polymer and a plasticizer, the volume-average particle size of the first organic particles satisfies (Dv90 - Dv10) / Dv50 ≤ 2.5, the vitrification transfer temperature of the first organic particles is 20-100°C, and the separator is 0.1 g·m －２ ・Ω －１ ≦ρ / R≦1.0g・m －２ ・Ω －１ A method for manufacturing a separator, wherein the following conditions are met, where ρ represents the surface density of the coating on the substrate and R represents the resistance of the separator at 25°C.

32. A secondary battery comprising a positive electrode plate, a negative electrode plate, a separator positioned between the positive electrode plate and the negative electrode plate, and an electrolyte, wherein the separator is the separator described in any one of claims 1 to 7.

33. The adhesive force between the positive electrode plate and the separator of the secondary battery satisfies 1.2 ≤ F2 / F1 ≤ 4. The secondary battery according to claim 32, wherein F1 represents the adhesive strength between the positive electrode plate and the separator at 25°C and ≥2 MPa, and F2 represents the adhesive strength between the positive electrode plate and the separator at 95°C and ≥2 MPa.

34. A battery module comprising the secondary battery described in claim 32.

35. A battery pack comprising the secondary battery described in claim 32.

36. A power consumption device including the secondary battery described in claim 32.

Images