Separator and manufacturing method thereof, battery and power consumption device

Abstract

The present application discloses a separator and a manufacturing method thereof, a battery, and a power consuming device, the separator comprising a substrate and a pressure-sensitive coating, the pressure-sensitive coating being formed on at least a portion of the surface of the substrate, the pressure-sensitive coating comprising composite particles and a first plasticizer, the composite particles forming protrusions on the coating surface, the composite particles comprising polyacrylate particles and inorganic particles, at least two polyacrylate particles having inorganic particles between them, the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles being 0.3 MPa. 1 / 2 -4MPa 1 / 2 It is.

Description

[Technical Field]

[0001] The present application relates to the field of secondary battery technology, and more particularly to a separator and its manufacturing method, a battery, and a power consuming device. [Background technology]

[0002] During the manufacturing process of the battery core of an electrochemical device, the electrodes and separators inevitably become misaligned during transfer. If the electrodes are light, they will come into contact with each other, resulting in the scrap of the dry battery core. If the electrodes are heavy, they will wrinkle after full charge, seriously affecting the dynamic performance and reducing the safety performance of the battery core. Therefore, currently, an adhesive coating is applied to the separator, and in the first combination of the electrodes and separator of the electrochemical device, a suitable pressure is generally applied to pre-pressure to ensure a certain degree of adhesion between the electrodes and separator of the electrochemical device before proceeding to the next process. However, due to the requirements of production efficiency, the pressure and application time at this time are not sufficient to achieve a suitable adhesion between the electrodes and separator of the electrochemical device. Summary of the Invention

[0003] In view of the technical problems existing in the background art, the present application aims to provide a separator that satisfies the need to achieve proper adhesion between the electrode plates and the separator of an electrochemical device under different pressures.

[0004] In order to achieve the above object, a first aspect of the present application provides a separator, the separator including a substrate and a pressure-sensitive coating formed on at least a portion of the surface of the substrate, the pressure-sensitive coating including composite particles and a first plasticizer, the composite particles forming protrusions on the surface of the pressure-sensitive coating, the composite particles including polyacrylate particles and inorganic particles, the inorganic particles being disposed between at least two of the polyacrylate particles, and the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles being 0.3 MPa 1 / 2 -4 MPa 1 / 2 is.

[0005] Compared with the prior art, the present application has at least the following beneficial effects: The separator of the present application has good pressure-sensitive properties and compressive modulus, and its adhesive strength is 0.1 N / m or less under the action of ≦1 MPa, which prevents interlayer adhesion during winding and storage of the separator, and it can form a clear adhesive bond with the electrode plates under the action of a pressure of ≧2 MPa, so when this separator is used to manufacture a battery core, the electrode plates and the separator can be tightly attached under appropriate pressure at room temperature, improving the dynamic performance of the battery core.

[0006] In some embodiments of the present application, the first plasticizer comprises an ester-based compound, and the ester-based compound has a solubility parameter of 12 MPa or less. 1 / 2 -30 MPa 1 / 2 This can improve the pressure sensitive properties of the pressure sensitive coating while simultaneously reducing dissolution of the composite particles.

[0007] In some embodiments of the present application, the pressure-sensitive coating further comprises an emulsifier, which comprises at least one of an anionic emulsifier and a nonionic emulsifier, which is advantageous for uniformly distributing the first plasticizer in the composite particles, and further improves the manufacturing yield and pressure-sensitive properties of the separator.

[0008] In some embodiments of the present application, the pressure-sensitive coating comprises 80-96 parts by weight of composite particles, 5-30 parts by weight of an ester-based compound, and 0.1-0.5 parts by weight of an emulsifier, so that the separator has good pressure-sensitive properties and thereby improves the dynamic performance of the battery core.

[0009] In some embodiments of the present application, the Dv50 of the composite particles is ≥ 2.5 μm, preferably 2.5 μm-10 μm, more preferably 3 μm-8 μm, which is beneficial to form a protrusion structure on the pressure-sensitive coating surface, thereby improving the dynamic performance of the battery core.

[0010] In some embodiments of the present application, the composite particles include first agglomerates, and the first agglomerates include at least two of the inorganic particles, thereby improving the dynamic performance of the battery core.

[0011] In some embodiments of the present application, Dv50 of the first agglomerates is 0.01 μm≦Dv10 of the composite particles, thereby increasing the compressive modulus of the separator.

[0012] In some embodiments of the present application, the composite particles comprise inorganic particles in the form of primary particles.

[0013] In some embodiments of the present application, the Dv50 of the inorganic particles in the form of primary particles is 0.01 μm-1 μm, preferably 0.5 μm-1 μm, to ensure that the composite particles do not fuse together during fabrication and block the separator ion transport channels.

[0014] In some embodiments of the present application, the composite particles comprise second agglomerates, and the second agglomerates comprise at least two of the polyacrylate particles.

[0015] In some embodiments of the present application, the Dv50 of the second aggregates is 0.3 μm-5 μm, preferably 1 μm-2 μm.

[0016] In some embodiments of the present application, the polyacrylate particles include polyacrylate particles in the form of primary particles and / or polyacrylate particles in the form of secondary particles.

[0017] In some embodiments of the present application, the Dv50 of the primary particle-shaped polyacrylate particles is 50 nm-400 nm, preferably 100 nm-200 nm, which can improve the ionic conductivity of the entire separator pressure-sensitive coating, reduce the separator resistance, and improve the dynamic performance of the battery core.

[0018] In some embodiments of the present application, the Dv50 of the secondary particle-form polyacrylate particles is 2 μm-15 μm, preferably 5 μm-8 μm, which provides a buffer space for stress release between the electrodes and prevents damage to the bends of the wound battery core due to stress accumulation.

[0019] In some embodiments of the present application, the content of the inorganic particles in the composite particles is 1 wt%-50 wt%, preferably 1 wt%-40 wt%, more preferably 2 wt%-15 wt%, and most preferably 5 wt%-15 wt%, so that the separator has an appropriate compressive modulus.

[0020] In some embodiments of the present application, the height of each of the two surfaces of the protrusions is 15 μm-60 μm, which can improve the dynamic performance of the battery core while improving the battery safety.

[0021] In some embodiments of the present application, the surface of the protrusions has the first agglomerates, which can improve the dynamic performance of the battery.

[0022] In some embodiments of the present application, the glass transition temperature of the polyacrylate particles is 20°C-80°C, preferably 25°C-65°C, which can prevent adhesion of the composite particles during high-temperature granulation and improve the ion-conducting ability of the separator.

[0023] In some embodiments of the present application, the pressure-sensitive coating further comprises 4-20 parts by weight of a pressure-sensitive adhesive polymer, which comprises an adhesive polymer and a second plasticizer, thereby further improving the pressure-sensitive properties of the separator and the dynamic performance of the battery core.

[0024] In some embodiments of the present application, the average particle size of the adhesive polymer is 0.5 μm-3.0 μm, and optionally 0.8 μm-2.0 μm, which is advantageous for the pressure-sensitive adhesive polymer to be uniformly distributed among the composite particles, and improve the pressure-sensitive properties of the separator.

[0025] In some embodiments of the present application, the DSC melting point of the pressure-sensitive adhesive polymer is −50° C. to 100° C., and optionally −45° C. to 60° C. Therefore, when the DSC melting point of the pressure-sensitive adhesive polymer is within the above range, the adhesive strength at room temperature can be ensured, and the adhesive strength at 1 MPa can be prevented from being too strong, which would cause the separator to adhere when wound, while the adhesive strength at 2 MPa at room temperature can be prevented from being too weak, which would weaken the adhesion between the separator and the electrode plate and cause disadvantages to the shaping of the battery core.

[0026] In some embodiments of the present application, the mass ratio of the adhesive polymer to the second plasticizer is (4-19): 1, optionally (4-11): 1. Therefore, when the relative content of the second plasticizer in the pressure-sensitive adhesive polymer is within the above range, it can ensure that the electrode plate and the separator can obtain a relatively large adhesive force under a certain pressure without increasing the resistance of the separator and reducing the cycle performance of the battery.

[0027] In some embodiments of the present application, the pressure-sensitive adhesive polymer has a core-shell structure, and the core and shell of the core-shell structure both contain an adhesive polymer and a second plasticizer, where the mass ratio of the adhesive polymer to the second plasticizer in the core structure is (2-5):1, optionally (3-4):1, and the mass ratio of the adhesive polymer to the second plasticizer in the shell structure is (6-10):1, optionally (7-9):1, thereby further improving the pressure-sensitive performance of the pressure-sensitive adhesive polymer and thereby further enhancing the dynamic performance of the battery core.

[0028] In some embodiments of the present application, the adhesive polymer comprises a copolymer formed by the reaction of at least one of the following first monomers, at least one of the second monomers, at least one of the third monomers with at least one reactive dispersant monomer: First monomers: acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylol acrylamide, acrylamide, styrene, acrylonitrile; Second monomers include C4-C22 alkyl acrylates, isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl (isooctyl) acrylate, cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, ethylene urea ethyl methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, ethylene urea ethyl methacrylate, acrylic methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate; Third monomer: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, 3-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethyl (meth)acrylamide, diacetone acrylamide, methacrylic acid, ethyl acetoacetate, divinylbenzene, epoxy resin with an epoxy value of 0.35-0.50, including divinylbenzene; Reactive dispersants: include polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, polyvinyl alcohol.

[0029] This ensures that the adhesive polymer has proper swelling and adhesion, and that the pressure-sensitive adhesive polymer has proper swelling, pressure sensitivity and adhesion properties, as well as proper elastic modulus, so as to ensure the shaping effect, dynamic performance and safety performance of the battery core.

[0030] In some embodiments of the present application, the second plasticizer comprises at least one of a glycerol C4-C10 alkyl diether, a glycerol C4-C10 alkyl monoether, a glycerol C4-C10 carboxylic acid monoester, a glycerol C4-C10 carboxylic acid diester, a propylene glycol C4-C10 alkyl monoether, and glycerol.

[0031] In some embodiments of the present application, the pressure-sensitive coating further comprises organic particles, including at least one of polytetrafluoroethylene particles, polytrifluorochloroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of fluorine-containing alkenyl monomer units and ethylene monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylate monomer units, and particles of modified compounds of the above homopolymers or copolymers, wherein the organic particles and the composite particles form the protrusions on the coating surface, thereby improving the cycle performance and safety performance of the battery core.

[0032] In some embodiments of the present application, the organic particles form third aggregates.

[0033] In some embodiments of the present application, the Dv50 of the third aggregates is 5 μm-30 μm, preferably 5.0 μm-12 μm.

[0034] In some embodiments of the present application, the third aggregates include organic particles in the form of primary particles, and adjacent two of the organic particles have gaps between them, thereby improving the ionic conductivity of the separator.

[0035] In some embodiments of the present application, the Dv50 of the organic particles in the form of primary particles is 50 nm-400 nm, preferably 100 nm-200 nm.

[0036] In some embodiments of the present application, the mass ratio of the composite particles to the organic particles is (20-90):(0-70), preferably (45-90):(0-45), which can reduce the battery cost while improving its safety performance and cycle performance.

[0037] In some embodiments of the present application, the average thickness of the pressure-sensitive coating is 2 μm-20 μm, and optionally 2 μm-15 μm, which can ensure proper adhesion between the separator and the electrode plate and improve the dynamic performance of the battery core.

[0038] A second aspect of the present application provides a method for manufacturing a separator, the method comprising the step of forming a pressure-sensitive coating on at least a portion of a surface of a substrate, the pressure-sensitive coating comprising polyacrylate particles and a first plasticizer, the composite particles forming protrusions on a surface of the pressure-sensitive coating, the composite particles comprising polyacrylate particles and inorganic particles, the inorganic particles being disposed between at least two of the polyacrylate particles, and the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles being 0.3 MPa. 1 / 2 -4 MPa 1 / 2 is.

[0039] As a result, the separator of the present application has good pressure-sensitive properties and compressive modulus. Its adhesive strength at a pressure of ≦1 MPa is ≦0.1 N / m, which prevents interlayer adhesion during winding and storage of the separator. It can also form a clear adhesive bond with the electrode plates at a pressure of ≧2 MPa. Therefore, when this separator is used to manufacture a battery core, the electrode plates and the separator can be tightly attached under appropriate pressure at room temperature, improving the dynamic performance of the battery core.

[0040] A third aspect of the present application provides a battery, the battery comprising a separator according to the first aspect of the present application or comprising a separator produced by the method of the second aspect of the present application.

[0041] A fourth aspect of the present application provides a power consuming device, the device comprising a battery according to the third aspect of the present application, the battery being adapted to provide electrical energy. Because the power consuming device of the present application comprises the battery according to the present application, it has at least the same advantages as the battery. [Brief explanation of the drawings]

[0042] In order to more clearly explain the technical solution of the present application, the following briefly introduces the drawings used in the present application. It is obvious that the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on the drawings without any creative efforts.

[0043] [Figure 1] FIG. 2 is a schematic view of a battery core wound after a separator, a positive electrode plate, and a negative electrode plate are stacked in an embodiment of the present application. [Figure 2] FIG. 2 is a schematic diagram of a model structure of a separator according to an embodiment of the present application. [Figure 3] 1 is a structural schematic diagram of a battery according to an embodiment of the present application; [Figure 4] 1 is a structural schematic diagram of a battery module according to an embodiment of the present application; [Figure 5] 1 is a structural schematic diagram of a battery pack according to an embodiment of the present application; [Figure 6] FIG. 6 is an exploded view of FIG. 5. [Figure 7] 1 is a schematic diagram of an embodiment of a power consuming device in which a battery is used as a power source; DETAILED DESCRIPTION OF THE INVENTION

[0044] The present application will be further described below in conjunction with the detailed description of the present invention. It should be understood that these specific embodiments are only used to illustrate the present application and are not intended to limit the scope of the present application.

[0045] For the sake of brevity, this specification specifically discloses only a few numerical ranges. However, any lower limit may be combined with any upper limit to form an unspecified range, and any lower limit may be combined with another lower limit to form an unspecified range, and similarly, any upper limit may be combined with any other upper limit to form an unspecified range. Furthermore, each point or single numerical value disclosed alone may itself be combined as a lower limit or upper limit with any other point or single numerical value, or with other lower limits or upper limits to form an unspecified range.

[0046] In the description of this specification, unless otherwise specified, the term "or" is inclusive. That is, the phrase "A or B" means "A, B, or both A and B." More specifically, "A or B" is satisfied when A is true (or exists) and B is false (or does not exist), when A is false (or does not exist) but B is true (or exists), or when both A and B are true (or exist).

[0047] In the description of this specification, it should be explained that unless otherwise specified, "more than" and "less than" are inclusive, and "multiple" in "one or more" means two and more than two.

[0048] Unless otherwise specified, the terms used in this application have the meanings commonly understood by those skilled in the art. Unless otherwise specified, the numerical values ​​of each parameter mentioned in this application can be measured using various measurement methods commonly used in the art (for example, can be tested using the methods described in the examples of this application).

[0049] An embodiment of the present application provides a separator, the separator including a substrate and a pressure-sensitive coating formed on at least a portion of the surface of the substrate, the pressure-sensitive coating including composite particles and a first plasticizer, the composite particles forming protrusions on the surface of the pressure-sensitive coating, the composite particles including polyacrylate particles and inorganic particles, the inorganic particles being disposed between at least two of the polyacrylate particles, and the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles being 0.3 MPa. 1 / 2 -4 MPa 1 / 2 is.

[0050] It should be noted that the pressure-sensitive coating being formed on at least a portion of the surface of the substrate can be understood as the pressure-sensitive coating being in direct contact with the surface of the substrate, i.e., "direct contact," or as another layer being present between the surface of the substrate and the pressure-sensitive coating, i.e., "indirect contact." At the same time, the phrase "at least two of the polyacrylate particles have inorganic particles between them, and the composite particles form protrusions on the surface of the pressure-sensitive coating" can be understood by cutting the separator along its thickness direction and scanning the cross section of the separator pressure-sensitive coating with a scanning electron microscope (SEM). As can be seen from the SEM image, the composite particles include polyacrylate particles and inorganic particles, and some of the polyacrylate particles have inorganic particles between them, and the composite particles can form protrusions on the surface of the pressure-sensitive coating.

[0051] Specifically, the test was performed using a ZEISS Sigma300 scanning electron microscope, following the steps below: First, cut the separator into a 6mm x 6mm sample, sandwich the sample between two sheets of electrically and thermally conductive copper foil, and secure the sample to the copper foil with double-sided tape. The smaller the gap between the sample and the copper foil, the better. Press the sample with a 400g flat iron block for one hour. Then, trim the edges with scissors and attach the sample to a sample holder with conductive adhesive, ensuring that the sample protrudes slightly beyond the edge of the holder. Then, place the sample holder in the sample rack, lock it in place, and turn on the IB-19500CP argon ion cross-section polisher at 10 Pa. -4 The specimen was evacuated to 0.15 Pa, the argon gas flow rate was set to 0.15 MPa, the voltage to 8 KV, and the polishing time to 2 hours. The specimen stage was then adjusted to oscillation mode and polishing began. After polishing was completed, an ion-polished cross-sectional morphology (CP) image of the specimen was obtained using a ZEISS Sigma 300 scanning electron microscope.

[0052]

[0003] Without wishing to be limited by any theory, the inventors have, after extensive research, found that the separator pressure-sensitive coating employed in this application comprises composite particles and a first plasticizer, the composite particles comprising polyacrylate particles and inorganic particles, with inorganic particles between at least two polyacrylate particles, which prevents adhesion of the composite particles during high-temperature granulation, improves the separator's ion-conducting ability, and improves the compressive modulus of the composite particles, resulting in relatively adequate adhesion between the separator and the electrode plate. While conventional separator coatings employ polyvinylidene fluoride particles, the separator coating of this application comprises composite particles and a first plasticizer, which reduces the separator's resistance, and the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles is 0.3 MPa. 1 / 2 -4 MPa 1 / 2The first plasticizer can plasticize the composite particles, thereby improving the pressure-sensitive properties of the separator and the dynamic performance of the battery core, as well as ensuring proper adhesion between the separator and the electrode plates during the fabrication and use of the battery core. Most importantly, it provides the separator with an appropriate compressive modulus, preventing the battery core from blocking the lithium ion transmission channels and deteriorating the dynamic performance when the cycle expansion force increases, thereby improving the dynamic performance of the battery. At the same time, when the battery experiences thermal runaway and high temperatures, the protrusions formed on the coating surface by the composite particles form a large-area adhesive film structure that reduces or blocks the ion transmission channels and delays heat diffusion in the battery, thereby effectively improving the cycle performance and high-temperature safety of the battery. As a result, the separator of the present application has good pressure-sensitive properties and compressive modulus. Its adhesive strength at a pressure of ≦1 MPa is ≦0.1 N / m, which prevents interlayer adhesion during winding and storage of the separator. It can also form a clear adhesive bond with the electrode plates at a pressure of ≧2 MPa. Therefore, when this separator is used to manufacture a battery core, the electrode plates and the separator can be tightly attached under appropriate pressure at room temperature, improving the dynamic performance of the battery core.

[0053] After extensive research, the present inventors have found that the performance of the battery can be further improved if the separator of the present application satisfies the above conditions and, in addition, optionally satisfies one or more of the following conditions:

[0054] In some embodiments, the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles is 0.3 MPa 1 / 2 -4 MPa 1 / 2 , e.g., 0.4 MPa 1 / 2 -3.8 MPa 1 / 2 , 0.5 MPa 1 / 2 -3.6 MPa 1 / 2 , 0.7 MPa 1 / 2 -3.5 MPa 1 / 2 , 0.9 MPa 1 / 2 -3.2 MPa 1 / 2 , 1 MPa 1 / 2-3 MPa 1 / 2 , 1.2 MPa 1 / 2 -2.8MPa 1 / 2 , 1.5 MPa 1 / 2 -2.5MPa 1 / 2 , 1.8 MPa 1 / 2 -2.2MPa 1 / 2 , 2 MPa 1 / 2 -2.2MPa 1 / 2 The inventors found that the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles was too large (4 MPa 1 / 2 When the solubility parameter of the first plasticizer is too small (over 0.3 MPa), the plasticizing effect of the first plasticizer on the composite particles is relatively small, but the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles is too small (over 0.3 MPa). 1 / 2 It was found that if the solubility parameter of the composite particles is smaller than 0.05, the composite particles are easily dissolved, causing the separator to stick during storage, which in turn causes the slurry to clump together when the separator is applied, making production difficult. Therefore, by using a first plasticizer whose solubility parameter with the composite particles satisfies the above difference, the plasticizing effect of the first plasticizer on the composite particles can be ensured, thereby improving the pressure-sensitive properties of the separator and the dynamic performance of the battery core.

[0055] According to some examples, the solubility parameter of the first plasticizer is SP=(E / V) 1 / 2 where E is the cohesive energy in J and V is the volume in m 3 where E / V is the cohesive energy density. There are various methods for measuring it. For example, the boiling point of a substance is measured, and the boiling point T b The empirical formula for the heat of vaporization ΔH is ΔH=-2950+23.7T b +0.02T b 2 The heat of vaporization ΔH at room temperature is calculated using the formula below, and the solubility parameter SP = (E / V) 1 / 2 =((ΔH-RT) / V m ) 1 / 2 where R is the gas constant, with a value of 8.31 J / (mol K), T is the room temperature, with a unit of K, and V m is the unit molar liquid volume (m3 / mol), and T is room temperature (K).

[0056] The solubility parameter of the composite particle is equal to the solubility parameter of the polyacrylate particle. The solubility parameter SP of the polyacrylate particle is obtained by comparing the solubility parameter of the monomer homopolymer of the polyacrylate particle. When the polyacrylate particle contains various monomers, the solubility parameter is calculated by the root of the sum of the squares of the monomer mass% * monomer homopolymer solubility parameter. For example, polyacrylate contains three types of monomers A, B and C, and the mass% of monomer A is a, and the solubility parameter of the homopolymer of monomer A is SP. A and the mass % of monomer B is b, and the solubility parameter of the homopolymer of monomer B is SP b where the mass % of monomer C is c and the solubility parameter of the homopolymer of monomer C is SP c and the solubility parameter of the polyacrylate particles is SP = (a * SP a 2 + b*SP b 2 + c*SP c 2 ) 1 / 2 is.

[0057] In some embodiments, the first plasticizer comprises an ester-based compound, and the ester-based compound has a solubility parameter of 12 MPa or less. 1 / 2 -30 MPa 1 / 2 , e.g., 13 MPa 1 / 2 -29 MPa 1 / 2 , 14 MPa 1 / 2 -28 MPa 1 / 2 , 15 MPa 1 / 2 -27 MPa 1 / 2 , 16 MPa 1 / 2 -26 MPa 1 / 2 , 17 MPa 1 / 2 -25 MPa 1 / 2 , 18 MPa 1 / 2 -24 MPa 1 / 2 , 19 MPa1 / 2 -23 MPa 1 / 2 , 20 MPa 1 / 2 -22 MPa 1 / 2 The ester-based compound may be, for example, a carbonate ester-based compound, a carboxylic acid ester-based compound, or a lactone-based compound, such as, but not limited to, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, ethyl acetate, propyl propionate, butyl acetate, caprolactone, or diethylene glycol butyl ether acetate.

[0058] In some embodiments, the pressure-sensitive coating further comprises an emulsifier, the emulsifier comprising at least one of an anionic emulsifier and a nonionic emulsifier. The addition of the emulsifier allows the ester-based compound to be uniformly distributed in the composite particles, further improving the pressure-sensitive properties and manufacturing yield of the separator. For example, the anionic emulsifier may comprise an alkylbenzene sulfonate, and the nonionic emulsifier may comprise one or more of aliphatic alcohol polyoxyethylene ethers, alkylphenol polyoxyethylene ethers, fatty acid polyoxyethylene ethers, glycerol esters, and polyglyceryl stearate.

[0059] In some embodiments, the pressure-sensitive coating comprises 80-96 parts by weight of composite particles, 5-30 parts by weight of an ester-based compound, and 0.1-0.5 parts by weight of an emulsifier, e.g., 82-94 parts by weight of composite particles, 84-92 parts by weight of composite particles, 86-90 parts by weight of composite particles, 88-90 parts by weight of composite particles, 6-28 parts by weight of an ester-based compound, 8-26 parts by weight of an ester-based compound, 10-25 parts by weight of an ester-based compound, 12-22 parts by weight of an ester-based compound, 15-20 parts by weight of an ester-based compound, 15-18 parts by weight of an ester-based compound, 0.2-0.5 parts by weight of an emulsifier, 0.3-0.5 parts by weight of an emulsifier, or 0.4-0.5 parts by weight of an emulsifier. Therefore, when the composite particles, ester compound and emulsifier in the pressure-sensitive coating adopt the above composition, the pressure-sensitive properties of the pressure-sensitive coating can be further improved, and the adhesive strength between the separator and the electrode plate can be optimized, thereby improving the dynamic performance of the battery core.

[0060] According to one example, the preparation of the composite particles of the present application may refer to the following steps.

[0061] (1) providing a polymer monomer for producing polyacrylate particles, and polymerizing the polymer monomer to obtain a polyacrylate polymer; (2) adding a solvent and inorganic particles to the polyacrylate polymer obtained in step (1), and then stirring to obtain a mixed slurry; (3) The mixed slurry of step (2) is dried to remove the solvent, and then polished and crushed to obtain the composite particles described in the present application.

[0062] It should be noted that the polymerization of the polymer monomers may be carried out using polymerization methods commonly used in the art, for example, emulsion polymerization or suspension polymerization.

[0063] In some embodiments, in step (1), additives such as emulsifiers, for example, sodium lauryl sulfate, and polymerization initiators, for example, ammonium persulfate, may be added to the polymerization system of the polymer monomers.

[0064] In some embodiments, in step (1), the polymeric monomers from which the polyacrylate particles are made comprise at least: a first polymer monomer having at least one ester linkage and selectively 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; a second polymer monomer having at least one cyano bond and optionally one or more of acrylonitrile, methacrylonitrile, ethacrylonitrile, and further optionally one or more of acrylonitrile, methacrylonitrile; The polymer monomer has at least one amide bond and is optionally one or more of acrylamide, N-methylolacrylamide, and N-butoxymethacrylamide, and further optionally a third polymer monomer is optionally one or more of acrylamide and N-methylolacrylamide.

[0065] Thus, the polyacrylate particles are formed by polymerizing at least the three polymer monomers, and the separator can obtain suitable adhesion with the electrode plates, thereby improving the dynamic performance of the battery.

[0066] In some embodiments, the weight ratio of the first polymeric monomer to the second polymeric monomer to the third polymeric monomer in the formed polyacrylate particles is 1:0-0.8:0.05-0.75, e.g., 1:0.1-0.8:0.05-0.75, 1:0.1-0.7:0.05-0.75, 1:0.2-0.6 1:0-0.8:0.05-0.75, 1:0.3-0.5:0.05-0.75, 1:0.3-0.4:0.05-0.75, 1:0-0.8:0.05-0.7, 1:0-0.8:0.1-0.7, 1:0-0.8:0.15-0.65, 1:0-0.8:0.2-0.6, 1:0-0.8:0.3-0.5, or 1:0-0.8:0.4, thereby improving the dynamic performance of the battery. In some other embodiments, the weight ratio of the first polymeric monomer to the second polymeric monomer to the third polymeric monomer in the formed polyacrylate particles is 1:0.1-0.6:0.1-0.6.

[0067] In some embodiments, in step (2), the inorganic particles include one or more of oxides of silicon, aluminum, calcium, zinc, magnesium, and sodium sulfate, sodium benzoate, calcium carbonate, and modifications thereof, and optionally one or more of silicon dioxide, silicon dioxide sol, aluminum oxide, zinc oxide, magnesium oxide, and sodium benzoate, and further optionally one or more of fumed silicon dioxide, silicon powder, aluminum oxide, and sodium benzoate.

[0068] In some embodiments, in the separator of the present application, the Dv50 of the composite particles is ≥ 2.5 μm, for example, 2.5 μm-10 μm, 2.5 μm-8 μm, 2.5 μm-6 μm, 2.5 μm-5 μm, 2.5 μm-4 μm, 2.5 μm-3 μm, etc. Therefore, on the one hand, composite particles satisfying this Dv50 range can provide adequate adhesion between the separator pressure-sensitive coating and the electrode plate, and on the other hand, are advantageous for forming a protrusion structure on the surface of the pressure-sensitive coating, thereby improving the dynamic performance of the battery core.

[0069] In some embodiments, the separator of the present application has first agglomerates between the polyacrylate particles, and the first agglomerates contain at least two inorganic particles. This prevents the composite particles from becoming too soft, thereby ensuring proper interaction between the composite particles and the electrode plate and between the composite particles and the substrate when the battery expands or a relatively large external force is applied, thereby improving the battery's dynamic performance. It also prevents the composite particles from fusing together during fabrication and blocking the ion transport channels. Furthermore, when the first agglomerates formed by the inorganic particulate material are present inside or on the surface of the composite particles, the spherical shape of the composite particles does not soften or collapse at high temperatures (e.g., ≥ 45°C) and under stresses of ≥ 0.4 MPa, thereby ensuring proper interaction between the composite particles and the electrode plate and between the composite particles and the substrate. This prevents deterioration of the battery's cycle performance and further improves the battery's dynamic performance.

[0070] In some embodiments, 0.01 μm≦Dv50 of the first agglomerates≦Dv10 of the composite particles, thereby increasing the compressive modulus of the separator.

[0071] In some embodiments, in the separator of the present application, the composite particles comprise inorganic particles in the form of primary particles. Furthermore, the Dv50 of the inorganic particles in the form of primary particles is 0.01 μm-1 μm, for example, 0.01 μm-0.8 μm, 0.05 μm-1 μm, 0.1 μm-1 μm, 0.2 μm-1 μm, 0.3 μm-1 μm, 0.4 μm-1 μm, 0.5 μm-1 μm, 0.6 μm-1 μm, 0.7 μm-1 μm, 0.8 μm-1 μm, 0.9 μm-1 μm, etc. Inorganic particles satisfying this Dv50 can ensure that the separator has an appropriate compressive modulus, thereby improving the dynamic performance of the battery. In some other embodiments, the Dv50 of the inorganic particles in the form of primary particles is 0.5 μm-1 μm, thereby improving the dynamic performance of the battery.

[0072] It should be noted that primary particles and secondary particles have the meanings known in the art. Primary particles are particles that do not form agglomerates. Secondary particles are particles that are in an agglomerated state, formed by the agglomeration of two or more primary particles. Primary particles and secondary particles can be easily distinguished from each other by scanning electron microscope (SEM) images.

[0073] In some embodiments, in the separator of the present application, the composite particles include second agglomerates, and the second agglomerates include at least two of the polyacrylate particles. This prevents the composite particles from becoming too soft, thereby ensuring proper interaction between the composite particles and the electrode plate and between the composite particles and the separator substrate when the battery expands or a relatively large external force is applied, thereby improving the battery's dynamic performance. Furthermore, the Dv50 of the second agglomerates is 0.3 μm-5 μm, e.g., 0.5 μm-5 μm, 0.7 μm-4.5 μm, 1 μm-4 μm, 1.3 μm-3.5 μm, 1.5 μm-3.2 μm, 1.7 μm-3 μm, 2 μm-2.8 μm, 2 μm-2.5 μm, 5 μm-10 μm, 5 μm-9 μm, 5 μm-8 μm, 5 μm-7 μm, 5 μm-6 μm, etc. In some other embodiments, the Dv50 of the second aggregates is 1 μm-2 μm.

[0074] In some embodiments, in the composite particles of the present application, the polyacrylate particles include polyacrylate particles in the form of primary particles and / or polyacrylate particles in the form of secondary particles, wherein the Dv50 of the polyacrylate particles in the form of primary particles is 50 nm-400 nm, e.g., 50 nm-375 nm, 75 nm-375 nm, 100 nm-350 nm, 125 nm-325 nm, 150 nm-300 nm, 175 nm-275 nm, 200 nm-250 nm, 200 nm-225 nm, etc. In other embodiments, the Dv50 of the polyacrylate particles in the form of primary particles is 100 nm-200 nm. The Dv50 of the secondary particle form polyacrylate particles is 2 μm-15 μm, for example, 3 μm-15 μm, 4 μm-12 μm, 5 μm-10 μm, 5 μm-8 μm, 5 μm-7 μm, 5 μm-6 μm, etc.

[0075] In some embodiments, the content of the inorganic particles in the composite particles is 1 wt%-50 wt%, e.g., 1 wt%-48 wt%, 1 wt%-45 wt%, 1 wt%-40 wt%, 1 wt%-35 wt%, 1 wt%-30 wt%, 1 wt%-25 wt%, 1 wt%-20 wt%, 1 wt%-15 wt%, 2 wt%-15 wt%, 3 wt%-15 wt%, 4 wt%-15 wt%, 5 wt%-15 wt%, 7 wt%-15 wt%, 10 wt%-15 wt%, 12 wt%-15 wt%, etc. By controlling the content of inorganic particles in the composite particles within the above content range, on the one hand, adhesion between polyacrylate particles due to high-temperature treatment during granulation does not occur, improving the ion conduction ability of the separator, and on the other hand, the separator has an appropriate compressive elastic modulus, ensuring an appropriate force between the separator coating and the anode when the battery module is subjected to force.

[0076] In some embodiments, the polyacrylate particles have a glass transition temperature of 20° C.-80° C., e.g., 25° C.-75° C., 30° C.-70° C., 35° C.-65° C., 40° C.-60° C., 45° C.-55° C., or 45° C.-50° C. By using polyacrylate particles that satisfy this glass transition temperature, adhesion during high-temperature granulation of composite particles can be avoided and the separator ion conduction capability can be improved. In other embodiments, the polyacrylate particles have a glass transition temperature of 25° C.-65° C.

[0077] In some embodiments, the separator coating surface of the present application includes protrusions, each having a height of 15 μm-60 μm, such as 15 μm-58 μm, 16 μm-56 μm, 18 μm-55 μm, 20 μm-52 μm, 22 μm-40 μm, 25 μm-40 μm, 25 μm-38 μm, 25 μm-36 μm, 28 μm-35 μm, or 30 μm-32 μm. Therefore, protrusions within this height range can provide adequate space between the separator and the electrode plate to relieve stress, prevent breakage during electrode plate winding, and improve safety. Furthermore, the protrusions also leave adequate gaps between the separator and the electrode plate, which facilitates electrolyte flow and infiltration, improving the dynamic performance of the battery core. Furthermore, the surface of the protrusions includes primary aggregates. Thereby, the protrusions can provide suitable adhesion between the separator and the electrode plate, thereby enhancing the dynamic performance of the battery.

[0078] Specifically, a pressure-sensitive coating is formed on both opposing surfaces of the substrate, and the sum of the protrusion heights on the pressure-sensitive coating on both sides is the height of the two sides of the protrusion. The test method for the height of the two sides of the protrusion is as shown in Figure 1. First, the negative electrode plate, separator, and positive electrode plate are stacked in order to form a battery core, and then wound up (the outermost layer of the battery core ends with the convex surface of the positive electrode plate). A CT device (ZEISS-1500) is then used to scan a position 15±1 mm below the edge of the negative electrode plate at the bend of the wound battery core. On the obtained CT image, samples are taken along the horizontal and tilt angle (30-45°) and a line is drawn in the direction of the largest gap. The sampling position for the inner five folds is from the convex surface of the innermost positive electrode plate to the convex surface of the fifth layer positive electrode plate, and the average value is taken for four folds. After six folds, the sampling position is from the convex surface of the inner layer positive electrode plate to the convex surface of the outer layer positive electrode plate, and a value is taken every five folds.

[0079] Average gap value of the five inner layers = [CT measurement distance - 4 * thickness of negative electrode plate after cold pressing * (1 + repulsion rate of negative electrode plate) - 4 * thickness of positive electrode plate after cold pressing (1 + repulsion rate of positive electrode plate) - 8 * thickness of separator] / 8 Average gap value from layer 6 to 10 onwards = [CT measurement distance - 5 * thickness of negative electrode plate after cold pressing * (1 + repulsion rate of negative electrode plate) - 5 * thickness of positive electrode plate after cold pressing (1 + repulsion rate of positive electrode plate) - 10 * thickness of separator] / 10 Here, the repulsion rate of the negative electrode plate = (thickness of the negative electrode plate before inserting the shell - thickness of the negative electrode plate after cold pressing) / thickness of the negative electrode plate after cold pressing, The repulsion rate of the positive electrode plate = (thickness of the positive electrode plate before inserting the shell - thickness of the positive electrode plate after cold pressing) / thickness of the positive electrode plate after cold pressing, The height of both sides of the separator protrusion = (average gap value of the inner 5 layers + average gap value of the inner 6-10 layers and beyond) / 2.

[0080] In some embodiments, the pressure-sensitive coating further comprises 4-20 parts by weight of a pressure-sensitive adhesive polymer, e.g., 5-18 parts by weight, 7-16 parts by weight, 9-15 parts by weight, 11-15 parts by weight, and the pressure-sensitive adhesive polymer comprises an adhesive polymer and a second plasticizer. The combined effect of the adhesive polymer and the second plasticizer allows the pressure-sensitive adhesive polymer to have good pressure-sensitive properties. The separator also has good pressure-sensitive properties, with an adhesive strength of 0.1 N / m or less under a pressure of ≦1 MPa, thereby preventing interlayer adhesion during winding and storage of the separator. It also exhibits significant adhesion to the electrode plates under a pressure of ≧2 MPa. Therefore, when this separator is used to manufacture battery cores, the electrode plates and the separator can be tightly attached at room temperature under appropriate pressure. This avoids misalignment between the electrode plates and the separator, which can lead to the disposal of the battery core and affect the performance of the battery core and pose safety risks. It also eliminates the need for a tunnel furnace and a second combined process in the conventional battery core production process, thereby saving production space and time, reducing energy consumption, and significantly increasing the production capacity of battery cores. At the same time, it also improves the shaping, safety, and dynamic performance of the battery cores, thereby improving the safety and dynamic performance of secondary batteries including this battery core and power consumption devices including this secondary battery.

[0081] In some embodiments, the mass ratio of the adhesive polymer to the second plasticizer in the pressure-sensitive adhesive polymer may be (4-19):1, such as (4-18):1, (4-15):1, (4-12):1, (4-11):1, (4-10):1, (4-8):1, or (4-6):1. The relative content of the second plasticizer in the pressure-sensitive adhesive polymer within the above range can ensure a relatively high adhesive strength between the electrode plate and the separator without increasing the resistance of the separator or reducing the cycle performance of the secondary battery.

[0082] The content of the second plasticizer may be measured using a thermogravimetric analyzer, model STA449F3, manufactured by Shimadzu Corporation of Japan. For example, the test method is as follows: Approximately 10 mg of pressure-sensitive adhesive polymer solids are taken, and the original mass is M0. After heating to 200°C, the mass is M1. The plasticizer content is M0-M1, and the adhesive polymer content is M0-(M0-M1). The test conditions are a temperature range of -100-400°C, a nitrogen gas atmosphere, and a rate of 10°C / min.

[0083] In some embodiments, the pressure-sensitive adhesive polymer may have a core-shell structure, and the core and shell of the core-shell structure may both comprise an adhesive polymer and a second plasticizer, where the weight ratio of the adhesive polymer to the second plasticizer in the core structure may be (2-5):1, for example (3-4):1, and the weight ratio of the adhesive polymer to the second plasticizer in the shell structure may be (6-10):1, for example (7-9):1, (7-8):1. The core and shell of the core-shell structure, both composed of an adhesive polymer and a second plasticizer, can further improve the pressure-sensitive performance of the pressure-sensitive adhesive polymer, thereby further improving the dynamic performance of the separator. On the other hand, pressure-sensitive adhesive polymers contain a second plasticizer. Under a certain pressure (e.g., 1 MPa-2 MPa), the second plasticizer rapidly migrates between the adhesive polymer and the separator base material, plasticizing the adhesive polymer and extending its molecular chains. This generates intermolecular hydrogen bonding with the negative electrode plate's adhesive, such as SBR adhesive or CMC thickener, and the positive electrode plate's adhesive, such as PVDF, to enhance interfacial wetting and strengthen the riveting effect between the two interfaces. Under pressure of ≥ 2 MPa, the core structure is fractured, releasing the second plasticizer in the core, further enhancing the above effects.

[0084] In some embodiments, a portion of the second plasticizer is grafted to the adhesive polymer. For example, at least 5 wt% of the second plasticizer, based on the weight of the plasticizer, is grafted to the adhesive polymer. Grafting a portion of the second plasticizer to the adhesive polymer can prevent the second plasticizer from migrating into the electrolyte during cycling, consuming various functional additives in the electrolyte, increasing the resistance of the separator, and affecting the dynamic performance of the battery core. Here, when at least 5 wt% of the second plasticizer is grafted to the adhesive polymer backbone, the separator and the electrode plate can form a "disconnected yet connected" behavior, further improving the durability of the room-temperature adhesion and reducing repulsion, while also ensuring that excess second plasticizer does not migrate into the electrolyte during cycling and affect the performance of the battery core. Here, the graft rate may be detected by an infrared test method. Specifically, Fourier infrared spectrograms are obtained from each test of the adhesive polymer, the second plasticizer, and the pressure-sensitive adhesive polymer, and the pressure-sensitive adhesive polymer is measured at 1500 cm -1 -1700cm -1 A peak different from that of the adhesive polymer and the second plasticizer alone appears at position , and this peak represents the grafted second plasticizer. The area under the peak represents the amount of the grafted second plasticizer, and the graft rate of the second plasticizer can be calculated based on this.

[0085] In some embodiments, the adhesive polymer may have an average particle size of 0.5 μm-3.0 μm, e.g., 0.8 μm-2.8 μm, 1 μm-2.5 μm, 1.2 μm-2.3 μm, 1.5 μm-2 μm, or 1.8 μm-2 μm. Adhesive polymers meeting the average particle size specification of the present application help the pressure-sensitive adhesive polymer to be uniformly distributed in the composite particles, which helps to ensure adhesion between the core and shell and the electrode plate under a certain pressure. In some embodiments, the pressure-sensitive adhesive polymer may have an average particle size of 0.8 μm-2 μm.

[0086] Here, the average particle size of the pressure-sensitive adhesive polymer can be measured using a laser particle size analyzer (e.g., Malvern Master Size 3000) in accordance with standard GB / T19077.1-2016.

[0087] In some embodiments, the DSC melting point of the pressure-sensitive adhesive polymer may be −50° C. to 100° C., for example, −45° C. to 95° C., −40° C. to 90° C., −35° C. to 85° C., −30° C. to 80° C., −25° C. to 75° C., −20° C. to 70° C., −15° C. to 65° C., −10° C. to 60° C., −5° C. to 55° C., 0° C. to 50° C., 5° C. to 45° C., 10° C. to 40° C., 15° C. to 35° C., 20° C. to 30° C., or 25° C. to 30° C. Thus, a pressure-sensitive adhesive polymer satisfying the above DSC melting point can ensure adhesive strength at room temperature and avoid the adhesive strength being too high at 1 MPa, which would cause the separator to adhere when wound, and avoid the adhesive strength being too low at 2 MPa at room temperature, which would weaken the adhesion between the separator and the electrode plate and cause disadvantages to the shaping of the battery core.

[0088] In some examples, the DSC melting point has a meaning known in the art and may be measured using an instrument and method known in the art, such as a DSC melting point tester with the model number DSC 200F3 manufactured by NETZSC GmbH, Germany. In a specific example, the test method is as follows: Approximately 10 mg of sample is taken and tested. The test conditions are set as follows: temperature range: -100-200°C, nitrogen gas atmosphere, 10°C / min. The temperature corresponding to the absorption peak selected during the first heating is the corresponding DSC melting point.

[0089] In some embodiments, the adhesive polymer comprises a copolymer formed by copolymerizing a reactive monomer mixture of at least one of the following first monomers, at least one of the following second monomers, at least one of the following third monomers, and at least one of the following reactive dispersants: First monomers: their melting points are generally higher than 80°C and include acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylol acrylamide, acrylamide, styrene, and acrylonitrile; Second monomer: its melting point is generally 80°C or less, and includes C4-C22 alkyl acrylate, isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl (isooctyl) acrylate, cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, ethylene urea ethyl methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, ethylene urea ethyl methacrylate, acrylic methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, Third monomer: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, 3-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethyl (meth)acrylamide, diacetone acrylamide, methacrylic acid, ethyl acetoacetate, divinylbenzene, epoxy resin with an epoxy value of 0.35-0.50, including divinylbenzene; Reactive dispersants include polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, and polyvinyl alcohol. Optionally, the alcoholysis degree of these reactive dispersants is ≥85%, and the average polymerization degree is 400-2000, preferably ≥88%, and the average polymerization degree is 500-1600.

[0090] Therefore, the adhesive polymer thus formed has suitable swelling, pressure sensitivity and adhesive properties, as well as suitable elastic modulus, so that the battery core has excellent shaping effect, dynamic performance and safety performance.

[0091] It should be noted that in this application, the term "alcoholysis degree" refers to the percentage of hydroxyl groups in the product obtained after alcoholysis relative to the original groups, expressed in mole fraction %. For example, if the original groups (ester groups) are 100 and the hydroxyl groups after alcoholysis are 60, the alcoholysis degree is 60%.

[0092] It should be noted that in this application, the term "average degree of polymerization" means that a polymer is composed of homogeneous polymer molecules with different degrees of polymerization, and the degree of polymerization has a statistically average meaning. There are two most commonly used ways to express the average degree of polymerization: the degree of polymerization obtained by averaging the number of molecules is called the number-average degree of polymerization, and the degree of polymerization obtained by averaging the weight is called the weight-average degree of polymerization. In this application, the "average degree of polymerization" is the number-average degree of polymerization.

[0093] In some embodiments, the second plasticizer may include at least one of a glycerol C4-C10 alkyl diether or monoether, a glycerol C4-C10 carboxylic acid monoester or diester, a propylene glycol C4-C10 alkyl monoether, and glycerol.

[0094] In some examples, the pressure sensitive adhesive polymer may be synthesized by the following synthesis method, which includes the following steps:

[0095] Step 1: Add 0.1% by weight-1% by weight (based on the total weight of the reactive monomer mixture (including the first monomer, the second monomer, the third monomer, and the reactive dispersant), the auxiliary (including the emulsifier, the stabilizer, and the aqueous initiator) and the second plasticizer used in synthesizing the pressure-sensitive adhesive polymer, of an emulsifier (such as propyl sulfonate), and 2% by weight-3% by weight of an oligomer (such as stearyl methacrylate) with a number average molecular weight of ≦1000 and a melting point of 0°C-30°C to a solvent (such as deionized water), in that order, and control the rotation speed of the homogenizer to 8000 r / min-12000 r / min, for example 10000 r / min, to disperse the mixture for 20-60 minutes, for example 50 minutes, at a dispersion reaction temperature of 20°C-40°C, for example 25°C, to obtain a first mixed solution.

[0096] Step 2: Add 1%-4% by weight of a stabilizer to the first mixture, such as at least one of polyethylene oxide, allyl polyether sulfate, methylene succinic acid (itaconic acid), styrene sulfonic acid, sodium vinyl sulfonate, and sodium nanocellulose, and mix using a homogenizer at a rotation speed of 6000-8000 r / min, for example, 6500 r / min, for a time of 20-60 minutes, for example, 30 minutes, at a mixing reaction temperature of 20°C-60°C, for example, 45°C, to obtain a second mixture.

[0097] Step 3: Add 0.05%-0.5% by weight of an aqueous initiator to the second mixture, such as 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, and azobisisoheptonitrile. The homogenizer speed is controlled to 8000 r / min-12000 r / min, e.g., 8000 r / min, and the mixing time is 20-60 min, e.g., 30 min. The reaction temperature is 60°C-80°C, e.g., 72°C, to obtain a third mixture.

[0098] Step 4: Under the condition that the homogenizer rotation speed is 100 r / min-1000 r / min, for example 400 r / min, 35% by mass-45% by mass of the reaction monomer mixture is gradually and uniformly added dropwise to the third mixture (controlled so that the addition is completed exactly in 60 minutes), and the reaction time is 80 min-100 min, for example 80 min, to obtain a fourth mixture.

[0099] Step 5: Continue reacting the fourth mixture under conditions of a reaction temperature of 80°C-90°C, for example 84°C, a homogenizer rotation speed of 12000 r / min-18000 r / min, for example 15000 r / min, and a time of 120 min-240 min, for example 180 min, to obtain a fifth mixture.

[0100] Step 6: Add 10%-20% by weight of a second plasticizer, such as glycerol, to the fifth mixture, control the reaction temperature at 80°C-90°C, for example, 84°C, control the homogenizer rotation speed at 12000 r / min-18000 r / min, for example, 15000 r / min, and control the reaction time at 120 min-240 min, for example, 180 min, to obtain a sixth mixture.

[0101] Step 7: Add 0.05%-0.5% by weight of an aqueous initiator, such as ammonium persulfate-sodium bicarbonate, to the sixth mixture. Control the homogenizer speed at 8000-12000 r / min, for example, 8000 r / min, for 20-60 minutes, for example, 30 minutes. The reaction temperature is 60°C-80°C, for example, 72°C, to obtain a seventh mixture.

[0102] Step 8: Under the condition that the homogenizer rotation speed is 100 r / min-1000 r / min, for example 400 r / min, 30% by mass-40% by mass of the reaction monomer mixture is gradually and uniformly added dropwise to the seventh mixture (controlled so that the addition is completed exactly in 60 minutes), and the reaction time is 100 min-160 min, for example 120 min, to obtain an eighth mixture.

[0103] Step 9: Add 5%-20% by weight of a second plasticizer, such as glycerol, to the eighth mixture, control the reaction temperature to 80°C-90°C, for example 84°C, the homogenizer rotation speed to 12000 r / min-18000 r / min, for example 15000 r / min, and the time to 120 min-240 min, for example 180 min, to obtain a ninth mixture.

[0104] Step 10: The temperature of the ninth mixture is reduced to below 50°C, and the mixture is filtered and discharged to obtain a core-shell pressure-sensitive adhesive polymer. Those skilled in the art can also synthesize and obtain a non-core-shell pressure-sensitive adhesive polymer by following the above method (omitting steps 7-9 and changing the mass fractions of the second plasticizer and the reactive monomer mixture accordingly).

[0105] In some embodiments, the pressure-sensitive coating has an average thickness of 2 μm-20 μm, e.g., 4 μm-18 μm, 5 μm-15 μm, 7 μm-12 μm, or 10 μm-12 μm, which provides adequate pressure to adhere the electrode plates and separator together and improves the dynamic performance of the battery core. In some embodiments, the pressure-sensitive coating has an average thickness of 2 μm-15 μm.

[0106] In some embodiments, the separator coating of the present application may further include organic particles, including at least one of polytetrafluoroethylene particles, polytrifluorochloroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of fluorine-containing alkenyl monomer units and ethylene monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylate monomer units, and particles of modified compounds of the above homopolymers or copolymers, and the composite particles and the organic particles form the protrusions on the surface of the pressure-sensitive coating, thereby improving the cycling performance and safety performance of the battery.

[0107] In some embodiments, the organic particles of the separator coating of the present application form third agglomerates, wherein the Dv50 of the third agglomerates is 5 μm-30 μm, e.g., 5 μm-28 μm, 5 μm-25 μm, 5 μm-22 μm, 5 μm-20 μm, 5 μm-18 μm, 5 μm-15 μm, 5 μm-12 μm, 5 μm-10 μm, 5 μm-8 μm, 5 μm-6 μm, etc.

[0108] In some embodiments, the third aggregates include organic particles in the form of primary particles, with gaps between adjacent organic particles. These gaps may serve as ion transmission channels, thereby improving the ionic conductivity of the separator. In some embodiments, the Dv50 of the organic particles in the form of primary particles is 50 nm-400 nm, e.g., 50 nm-375 nm, 75 nm-375 nm, 100 nm-350 nm, 125 nm-325 nm, 150 nm-300 nm, 175 nm-275 nm, 200 nm-250 nm, 200 nm-225 nm, etc.; in other embodiments, the Dv50 of the organic particles in the form of primary particles is 100 nm-200 nm.

[0109] In this application, Dv50 refers to the particle size corresponding to the cumulative volume distribution percentage reaching 50%, and Dv10 refers to the particle size corresponding to the cumulative volume distribution percentage reaching 10%. In this application, the Dv10 and Dv50 of composite particles may both be measured using laser diffraction particle size analysis. For example, they may be measured using a laser particle size analyzer (e.g., Malvern Master Size 3000) in accordance with GB / T19077-2016. The Dv50 of inorganic particles in primary particle form, the Dv50 of polyacrylate particles in primary particle form, and the Dv50 of polyacrylate particles in secondary particle form may be calculated from a separator SEM image. For example, a separator SEM image at 10Kx magnification may be taken, and five parallel samples may be used for each sample, with 10 positions for each parallel sample, and 20 points selected at each position for calculation. Finally, the average value is calculated to determine the corresponding particle size. The Dv50 of the first agglomerate, the Dv50 of the second agglomerate, and the Dv50 of the third agglomerate may be calculated using the CP diagram of the separator. For example, a CP diagram of the separator is taken at a magnification of 5Kx, and five parallel samples are used for each sample, and ten positions are used for each parallel sample. 20 points are selected at each position and statistically analyzed. Finally, the average value is calculated to obtain the corresponding particle size.

[0110] In some embodiments, the mass ratio of the composite particles to the organic particles is (20-90):(0-70), for example, the mass ratio of the composite particles to the polyvinylidene fluoride particles is (20-90):(5-65), (20-90):(10-60), (20-90):(20-50), (20-90):(30-40), (30-80):(0-70), (40-70):(0-70), (50-60):(0-70), (30-80):(5-65), (40-65):(10-55), (45-60):(20-45), or (55-60):(30-45). This can improve the infiltration and distribution uniformity of the electrolyte, improve the high-temperature storage performance of the battery, and enhance the safety and cycle performance of the battery. In some other embodiments, the mass ratio of the composite particles to the organic particles is (45 to 90):(0 to 45), thereby improving the safety performance and cycle performance of the battery.

[0111] As shown in FIG. 2, the separator includes a substrate and a pressure-sensitive coating (not shown). The pressure-sensitive coating includes composite particles, organic particles, a first plasticizer, an emulsifier, and an adhesive. The first plasticizer and the emulsifier are uniformly distributed inside and between the composite particles. The composite particles and the organic particles are connected to the substrate via the adhesive. The composite particles and the organic particles form protrusions on the surface of the pressure-sensitive coating.

[0112] In some embodiments, the pressure-sensitive coating may further include other organic compounds, such as polymers for improving heat resistance, dispersants, wetting agents, and other types of adhesives. The other organic compounds are all non-particulate substances in the pressure-sensitive coating. The present application does not particularly limit the type of the other organic compounds, and any known material with good improving properties may be selected and used.

[0113] In this application, the substrate is a porous membrane material with good chemical and mechanical stability. In some embodiments, the substrate may be a single-layer membrane material or a multi-layer composite membrane material. When the substrate is a multi-layer composite membrane material, the materials of each layer may be the same or different.

[0114] In some embodiments, in the separator of the present application, the substrate may be a porous membrane or porous nonwoven web comprising 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. In other embodiments, the substrate is a porous membrane or porous nonwoven web comprising polyethylene and / or polypropylene. Selecting the above substrates for the separator is advantageous in that the substrate bonds with the coating via an adhesive to form a separator that is appropriately dense, porous, and capable of conducting lithium ions.

[0115] In some embodiments, the substrate of the separator of the present application has a porosity of 10% to 95%, optionally 35% to 45%, thereby improving the ionic conductivity of the separator and reducing the likelihood of contact between the positive and negative electrodes. In some embodiments, the substrate of the separator of the present application has a pore size of 0.1 μm to 50 μm, optionally 0.1 μm to 5 μm. By selecting a substrate with this pore structure, the separator has good ionic conductivity, reduces the likelihood of direct contact between the positive and negative electrodes, and further improves the kinetics and safety of the battery core.

[0116] In some embodiments, the thickness of the substrate is ≦10 μm, for example, the thickness of the substrate may be 5 μm-10 μm, 5 μm-9 μm, or 7 μm-10 μm. When the thickness of the substrate is controlled within a predetermined range, the battery energy density can be further improved while ensuring the cycle performance and safety performance of the battery.

[0117] In some embodiments, the peel force of the pressure-sensitive coating is 40 N / m or more, the separator has a thermal shrinkage of 5% or less in both the machine direction (MD) and the cross direction (TD) after being left in an unclamped state at 150°C for 1 hour, a heat gun failure size of 0 at 200°C, an adhesive strength between the separator and the electrode plate of 1.0 N / m or more, and a resistance of the separator at 25°C of 2 ohms or less.

[0118] According to some embodiments, the separator's air permeability, transverse tensile strength (MD), longitudinal tensile strength (TD), transverse breaking elongation, and longitudinal breaking elongation all have meanings known in the art and may be measured using methods known in the art, for example, by testing in accordance with standard GB / T36363-2018.

[0119] According to some embodiments, the material types of polyacrylate particles, ester compounds, emulsifiers, pressure-sensitive adhesive polymers, and organic particles may be tested using equipment and methods known in the art. For example, the infrared spectrum of the material may be tested to determine the characteristic peaks contained therein, thereby determining the material type. Specifically, infrared spectrum analysis of the organic particles may be performed using equipment and methods known in the art, such as an infrared spectrometer, such as a Nicolet IS10 Fourier transform infrared spectrometer, in accordance with GB / T 6040-2002, General Principles for Infrared Spectroscopy.

[0120] A second aspect of the present application further provides a method for manufacturing a separator, the method comprising: (1) providing a substrate; and (2) forming a pressure-sensitive coating on at least a portion of the surface of the substrate, the pressure-sensitive coating comprising polyacrylate particles and a first plasticizer, the composite particles forming protrusions on the surface of the pressure-sensitive coating, the composite particles comprising polyacrylate particles and inorganic particles, the inorganic particles being disposed between at least two of the polyacrylate particles, and the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles being 0.3 MPa. 1 / 2 -4 MPa 1 / 2 is.

[0121] Specifically, the substrate, the first plasticizer and the composite particles are the same as described above and will not be further described here.

[0122] In some embodiments, the separator includes a substrate and a pressure sensitive coating, the pressure sensitive coating being disposed on only one surface of the substrate.

[0123] In some embodiments, the separator includes a substrate and a pressure sensitive coating, the pressure sensitive coating being simultaneously applied to two surfaces of the substrate.

[0124] In some embodiments, step (2) may be performed by employing step (2-1) of providing a pressure-sensitive coating slurry comprising composite particles and a first plasticizer, and step (2-2) of applying the pressure-sensitive coating slurry to at least one side of the substrate and drying to obtain the separator.

[0125] In some embodiments, in step (2-1), the solvent in the pressure-sensitive coating slurry may be water, for example, deionized water.

[0126] In some embodiments, in step (2-1), the pressure-sensitive coating slurry may further include other organic compounds, such as a polymer for improving heat resistance, a dispersant, a wetting agent, or an emulsion-like adhesive, wherein the other organic compounds are all non-particulate in the dried coating.

[0127] In some embodiments, in step (2-1), the solid content of the pressure-sensitive coating slurry may be controlled to 10%-20%, for example, 12%-15% by weight, which can improve the yield of coating production and the coating adhesion performance.

[0128] In some embodiments, in step (2-1), the first plasticizer comprises an ester-based compound, and the solubility parameter of the ester-based compound is 12 MPa or less. 1 / 2 -30 MPa 1 / 2 is.

[0129] In some embodiments, in step (2-1), the pressure-sensitive coating slurry may further include an emulsifier, which may include at least one of an anionic emulsifier and a nonionic emulsifier. The addition of an emulsifier allows the ester-based compound to be uniformly distributed in the composite particles, further improving the pressure-sensitive properties and manufacturing yield of the separator. For example, the anionic emulsifier may include alkylbenzene sulfonate, and the nonionic emulsifier may include one or more of aliphatic alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ether, glycerol ester, and polyglyceryl stearate.

[0130] In some embodiments, in step (2-1), the pressure-sensitive coating slurry further comprises a pressure-sensitive adhesive polymer, and the pressure-sensitive adhesive polymer comprises an adhesive polymer and a second plasticizer. The combined effect of the adhesive polymer and the second plasticizer allows the pressure-sensitive adhesive polymer to have good pressure-sensitive properties. The separator also has good pressure-sensitive properties, with an adhesive strength of 0.1 N / m or less under a pressure of ≦1 MPa, thereby preventing interlayer adhesion during winding and storage of the separator. It also exhibits significant adhesion to the electrode plates under a pressure of ≧2 MPa. Therefore, when this separator is used to manufacture battery cores, the electrode plates and the separator can be tightly attached at room temperature under appropriate pressure. This avoids misalignment between the electrode plates and the separator, which can lead to the disposal of the battery core and affect the performance of the battery core and pose safety risks. It also eliminates the need for a tunnel furnace and a second combined process in the conventional battery core production process, thereby saving production space and time, reducing energy consumption, and significantly increasing the production capacity of battery cores. At the same time, it also improves the shaping, safety, and dynamic performance of the battery cores, thereby improving the safety and dynamic performance of secondary batteries including this battery core and power consumption devices including this secondary battery.

[0131] In some embodiments, the pressure-sensitive coating slurry further comprises organic particles, the organic particles comprising at least one of polytetrafluoroethylene particles, polytrifluorochloroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of fluorine-containing alkenyl monomer units and ethylene monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylate monomer units, and particles of modified compounds of the above homopolymers or copolymers.

[0132] In some embodiments, in step (2-2), the coating is performed using a coater.

[0133] In the examples of the present application, there is no particular limitation on the model number of the coater, and a commercially available coater may be used.

[0134] In some embodiments, in step (2-2), the coating may be performed by a process such as transfer coating, rotary spray coating, or dip coating, for example, the coating is performed by transfer coating.

[0135] In some embodiments, the coater includes a gravure roll, which is used to transfer the coating slurry to the substrate.

[0136] By controlling each of the above process parameters within a predetermined range, the performance of the separator of the present application can be further improved. Those skilled in the art can selectively adjust one or several of the above process parameters according to the actual production situation.

[0137] The above-mentioned base material, composite particles, ester-based compound, emulsifier, organic particles, pressure-sensitive adhesive polymer and organic particles are all commercially available.

[0138] A third aspect of the present application provides a battery, which includes the separator of the first aspect or a separator manufactured by employing the second aspect.

[0139] The battery is a battery that can be continuously used by activating the active material through a method of charging after discharging.

[0140] Generally, a battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. During charging and discharging, active ions shuttle between the positive and negative electrodes, absorbing and releasing ions. The separator is placed between the positive and negative electrodes to provide isolation. The electrolyte conducts ions between the positive and negative electrodes.

[0141] [Positive electrode plate] In a battery, the positive electrode plate generally includes a positive electrode current collector and a positive electrode film layer disposed on the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material.

[0142] The positive electrode current collector may be a conventional metal foil sheet or a composite current collector (a metal material may be deposited on a polymer substrate to form a composite current collector). For example, the positive electrode current collector may be aluminum foil.

[0143] The specific type of the positive electrode active material is not limited, and any active material known in the art that can be used for a battery positive electrode may be used, and those skilled in the art can select it according to actual needs.

[0144] For example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates with an olivine structure, and modified compounds thereof. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and modified compounds thereof. Examples of lithium phosphates with an olivine structure may include, but are not limited to, one or more of lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites, and modified compounds thereof. All of these materials are commercially available.

[0145] The modifying compound for each of the above materials may be one that performs doping modification and / or surface coating modification on the material.

[0146] The positive electrode layer generally further optionally contains an adhesive, a conductive agent and other optional auxiliary agents.

[0147] By way of example, the conductive agent may be one or more of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, Super P (SP), graphene, and carbon nanofibers.

[0148] By way of example, the adhesive may be one or more of styrene butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[0149] [Negative electrode plate] In a battery, the negative electrode plate generally includes a negative electrode current collector and a negative electrode film layer disposed on the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.

[0150] The negative electrode current collector may be a conventional metal foil sheet or a composite current collector (e.g., a metal material may be deposited on a polymer substrate to form a composite current collector). For example, the negative electrode current collector may be a copper foil.

[0151] The specific type of the negative electrode active material is not limited, and any active material known in the art for use in battery negative electrodes may be used. Those skilled in the art can select the material according to their actual needs. For example, the negative electrode active material may include, but is not limited to, one or more of artificial graphite, natural graphite, hard carbon, soft carbon, silicone-based materials, and tin-based materials. The silicone-based material may be selected from one or more of silicone alone, silicone oxide (e.g., silicon suboxide), silicone carbon composites, silicone nitrogen composites, and silicone alloys. The tin-based material may be selected from one or more of tin alone, stannic acid compounds, and tin alloys. All of these materials are commercially available.

[0152] In some embodiments, to further improve the energy density of the battery, the negative electrode active material may include a silicone-based material.

[0153] The negative electrode film layer generally further optionally contains an adhesive, a conductive agent and other optional auxiliary agents.

[0154] By way of example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0155] By way of example, the adhesive may include one or more of styrene butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[0156] By way of example, other optional auxiliaries may be thickeners and dispersants (eg, sodium carboxymethylcellulose CMC-Na), PTC thermistor materials.

[0157] [Electrolyte] The battery may include an electrolyte, which serves to conduct ions between the positive electrode and the negative electrode, and may include an electrolyte salt and a solvent.

[0158] By way of example, the electrolyte salt may include one or more of lithium hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF), lithium perchlorate (LiClO), lithium hexafluoroarsenate (LiAsF), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(oxalato)borate (LiBOB), lithium difluorophosphate (LiPOF), lithium difluorobis(oxalato)phosphate (LiDFOP), and lithium tetrafluoro(oxalato)phosphate (LiTFOP).

[0159] By way of example, the solvent may comprise one or more of 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).

[0160] In some embodiments, the electrolyte solution further includes additives, such as an additive for forming a negative electrode film or a positive electrode film, and may further include additives that can improve certain battery performance characteristics, such as an additive for improving the overcharge performance of the battery, an additive for improving the high-temperature performance of the battery, or an additive for improving the low-temperature performance of the battery.

[0161] In some embodiments, the battery may be a lithium ion secondary battery.

[0162] The embodiments of the present application are not particularly limited to the shape of the battery, which may be cylindrical, rectangular, or any other shape. Figure 3 shows a rectangular battery 1 as an example.

[0163] In some embodiments, the battery may include an outer casing used to package the positive and negative electrodes and the electrolyte.

[0164] In some embodiments, the exterior body may include a case and a cover plate. Here, the case may include a bottom plate and a side plate connected to the bottom plate, the bottom plate and the side plate surrounding the bottom plate forming a storage cavity. The case may have an opening communicating with the storage cavity, and the cover plate may be disposed over the opening to seal the storage cavity.

[0165] The positive electrode plate, the negative electrode plate, and the separator can be wound or stacked to form an electrode assembly. The electrode assembly is packaged in the receiving cavity. The electrolyte can be an electrolytic solution, which is impregnated into the electrode assembly. The number of electrode assemblies included in the battery can be one or more, and can be adjusted according to needs.

[0166] In some embodiments, the battery exterior may be a hard case, such as a hard plastic case, an aluminum case, or a steel case.

[0167] The exterior of the battery may be a pouch, for example, a bag-like pouch, and the material of the pouch may be plastic, for example, may include one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0168] In some embodiments, the batteries can be assembled into a battery module, and the number of batteries included in the battery module can be multiple, with the specific number being adjustable depending on the application and capacity of the battery module.

[0169] FIG. 4 shows an example of a battery module 2. Referring to FIG. 4, in the battery module 2, the plurality of batteries 1 may be arranged in order along the longitudinal direction of the battery module 2. Of course, they may be arranged in any other manner. Furthermore, the plurality of batteries 1 may be fixed by fasteners.

[0170] The battery module 2 may further include a housing having an accommodating space, and the plurality of secondary batteries 1 are accommodated in the accommodating space. In some embodiments, the battery module may be further assembled into 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.

[0171] 5 and 6 show an example of a battery pack 3. Referring to FIGS. 5 and 6, the battery pack 3 may include a battery box and a plurality of battery modules 2 installed in the battery box. The battery box includes an upper housing 4 and a lower housing 5, and the upper housing 4 is attached to the lower housing 5 as a lid to form a sealed space for accommodating the battery modules 2. The plurality of battery modules 2 may be arranged in the battery box in any manner.

[0172] [Power consumption equipment] The present application further provides a power consuming device, the power consuming device including the battery for providing electric energy. Specifically, the battery may be a power source for the power consuming device or an energy storage unit for the power consuming device. The power consuming device may be, but is not limited to, a mobile device (e.g., a mobile phone, a laptop), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck), an electric train, a ship, a satellite, or an energy storage system.

[0173] An example power consuming device is shown in Figure 7. The power consuming device may be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0174] Other examples of power consuming devices include mobile phones, tablet computers, and laptops, which generally require a thin design and may employ a battery as a power source.

[0175] In order to clarify the technical problems, technical solutions, and beneficial effects solved by the embodiments of the present application, the following will be described in more detail in conjunction with the embodiments and drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and does not constitute any limitation on the present application and its applications. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0176] 1. Separator manufacturing (1) A PE substrate is provided, the thickness of which is 9 μm, the hole diameter of which is 50 nm, and the porosity of which is 38%.

[0177] (2) Formulation of coating slurry: Comprising composite particles, a first plasticizer, an emulsifier, a pressure-sensitive adhesive polymer (whose glass transition temperature is about 10°C, its average particle size is 1.1 μm, and the adhesive polymer and the second plasticizer are in a mass ratio of 5:1 (wherein, based on the weight of the second plasticizer, 8 wt% of the second plasticizer is grafted to the adhesive polymer), and a small amount of deionized water, where the adhesive polymer is 30 wt% isobutyl acrylate + 25 wt% isooctyl acrylate + 5 wt% 2-hydroxypropyl acrylate + 15 wt% styrene + 22 wt% acrylamide + 3% polyethylene glycol copolymer, and the second plasticizer is glycerol), organic particles, and a dispersant (BYK-22136) are uniformly mixed in an appropriate amount of solvent deionized water to obtain a pressure-sensitive coating slurry with a solid content of 12% (based on weight); (3) The pressure-sensitive coating slurry formulated in step (2) is applied to two surfaces of the PE substrate using a coater and then dried to obtain separator 1, and the thickness of the pressure-sensitive coating on one side of this separator is 3 μm.

[0178] Here, the composite particles are manufactured by adopting the following steps.

[0179] a. At room temperature, the necessary monomers are uniformly mixed by stirring in the weight percentage ratio of 10 wt% of 2-hydroxyethyl acrylate, 66 wt% of n-butyl acrylate, 8 wt% of methyl methacrylate, 1 wt% of trimethylolpropane triacrylate, 10 wt% of acrylonitrile, and 5 wt% of acrylamide to obtain a mixed monomer; b. 2 kg of 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-neck flask equipped with a mechanical stirrer, a thermometer and a condenser, and emulsified by stirring at a rotation speed of 1600 rpm for 30 minutes. The temperature was then raised to 75°C under nitrogen gas protection, and after reacting for 4 hours, the pH was adjusted to 6.5 using a 1 wt% NaOH aqueous solution. The temperature was immediately lowered to below 40°C and the mixture was discharged, yielding an emulsion-state organic polymer with a solid content of about 45 wt%. c) The dry weight of the organic polymer and silicon dioxide were added to an appropriate amount of deionized water in a mass ratio of 9:1, and the mixture was thoroughly mixed for 1 hour. The solvent was then removed by spray drying to obtain a powder, which was then polished and pulverized to obtain composite particles with a Dv50 of 5 μm.

[0180] All of the materials used in the examples may be commercially available. For example: The inorganic particles may be purchased from Anhui Isshitong Technology Co., Ltd. The organic particles may be purchased from Ruyuan Dongyang Guangfu Resin Co., Ltd. The substrate may be purchased from Shanghai Enjie New Materials Co., Ltd.

[0181] The dispersant may be purchased from Changshu Weiyi Technology Co., Ltd.

[0182] The humectant may be purchased from DOW.

[0183] The first plasticizer may be purchased from Huntsman.

[0184] The emulsifier may be purchased from BASF.

[0185] The pressure sensitive adhesive polymer may be purchased from Indile Technology Group Co., Ltd.

[0186] The corresponding parameters in the manufacturing process of separator 1-63 are shown in Table 1-7.

[0187] [Table 1] TIFF0007729919000002.tif248168TIFF0007729919000003.tif248168TIFF0007729919000004.tif248168

[0188] [Table 2] TIFF0007729919000006.tif248168TIFF0007729919000007.tif248168TIFF0007729919000008.tif248168TIFF0007729919000009.tif248168

[0189]

Table 3

[0190]

Table 4

[0191]

Table 5

[0192]

Table 6

[0193]

Table 7

[0194] 2. Battery manufacturing Example 1 1. Manufacturing of positive electrode plates LiNi, the positive electrode active material 1 / 3 Mn 1 / 3 Co 1 / 3 O2, acetylene black as a conductive agent, and polyvinylidene fluoride (PVDF) as an adhesive were uniformly mixed in a mass ratio of 94:3:3 in N-methylpyrrolidone (NMP) as a solvent to obtain a positive electrode slurry. The positive electrode slurry was then applied to a positive electrode current collector aluminum foil, followed by drying, cold pressing, stripping, and cutting to obtain a positive electrode plate. The amount of positive electrode active material carried on the positive electrode plate was 0.32 g / 1540.25 mm. 2 and the density is 3.45 g / cm 3 is.

[0195] 2. Manufacturing of negative electrode plates The active material, artificial graphite, the conductive agent, acetylene black, the adhesive, styrene butadiene rubber (SBR), and the thickener, sodium methyl cellulose (CMC), were mixed in a weight ratio of 95:2:2:1 with deionized water to obtain a negative electrode slurry. This slurry was then coated onto a negative electrode current collector, Cu foil, dried, and cold-pressed to obtain a negative electrode plate. The amount of graphite loaded on the negative electrode plate was 0.18 g / 1540.25 mm. 2 and the density is 1.65 g / cm 3 is.

[0196] 3. Separator The separator used was the separator 1 manufactured above.

[0197] 4. Electrolyte production 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 solution to obtain an electrolyte solution with a LiPF6 concentration of 1 mol / L.

[0198] 5. Battery manufacturing A positive electrode plate, a separator, and a negative electrode plate are stacked in this order, with the separator positioned between the positive and negative electrodes to act as an insulator, and then wound to obtain an electrode assembly. The electrode assembly is placed in an outer casing, and the above-prepared electrolyte is injected into the secondary battery after drying. The secondary battery is then vacuum packaged, left to stand, chemically formed, and shaped to obtain the secondary battery.

[0199] The secondary batteries of Examples 2-60 and Comparative Examples 1-3 are manufactured using methods similar to those of the battery of Example 1, with the difference being the use of different separators. The secondary batteries of Examples 2-60 use separators 2-60, and the secondary batteries of Comparative Examples 1-3 use separators 61-63.

[0200] 3. Evaluation of adhesive performance between separator and positive or negative electrode plate The test process is as follows:

[0201] 1. The separator with a length of 300 mm and a width of 100 mm and the positive and negative electrode plates prepared above were selected.

[0202] 2. The top and bottom of the separator were wrapped in paper and cut into 54.2mm x 72.5mm samples using a knife die and a press.

[0203] 3. The cut-out separator sample and the positive or negative electrode plate were stacked neatly, taking care that the separator was on top. 130mm x 130mm Teflon sheets were placed on the top and bottom, and the stacked sample was placed in the center of the cardboard and covered with a piece of 150mm x 160mm cardboard.

[0204] 4. The laminated sample was placed in a flat press to adjust the pressure, and the air pressure was adjusted to 1150KG±10KG (equivalent to approximately 3MPa) or 2650KG±10KG (equivalent to approximately 7MPa). The temperature was set to 25°C or 95°C, and the time was set to 10s, followed by heat pressing.

[0205] 5. The hot-pressed sample was cut into small pieces of 72.5mm x 15mm using a knife die and a press.

[0206] 6. One side of the electrode plate was attached to a steel plate with double-sided tape, and a separator was attached to the other side. A 15mm wide piece of A4 paper was then attached to the separator using double-sided tape to complete the production of the test sample. During the test, the steel plate that held the electrode plate in place was fixed, and a tension machine was used to pull the A4 paper upward, separating the separator from the electrode plate.

[0207] 7. Turn on the Gotech tensile tester and set it to the adhesion test speed of 50mm / min and starting jig pitch of 40mm.

[0208] 8. The test sample was placed between the jigs, the end of the steel plate was fixed to the lower collet, and an A4 sheet of paper was fixed to the upper collet. The upper and lower collets were clamped by the jigs, respectively.

[0209] 9. Click on the computer desktop stretching operation interface, clear the force, displacement, etc., and click "Start" to perform a pre-stretch of about 5 mm. After pre-stretching, clear the force, displacement, etc. again and start the test. After the test is completed, export and save the complete data.

[0210] 10. Each group should measure at least five test samples, and if the repeatability of the adhesive strength test curves of the five test samples is relatively good, the next group should be tested; otherwise, the test should be repeated until the repeatability of the five test samples is relatively good.

[0211] 11. After the test was completed, an adhesive strength (N / m)-displacement curve was created and the magnitude of the adhesive force was calculated.

[0212] 4. Evaluation of separator resistance performance The test process is as follows:

[0213] (1) Separator preparation: Each test separator was cut into samples of the same size (45.3mm*33.7mm), and the samples were baked in an environment of 60°C for at least 4 hours, and then quickly transferred to a 25°C 100-grade cleaning glove box for storage. (2) Manufacturing of symmetrical battery containment pocket pouch (symmetrical battery containment aluminum plastic pouch (aluminum plastic pouch is a general-purpose product made by combining polypropylene and aluminum foil for pouch cells)): A blank symmetrical battery assembled with Cu Foil vs. Cu Foil (copper foil vs. copper foil) as a current collector was used. The containment of this pocket pouch was achieved by green adhesive intermediate punching. Before use, the pocket pouch should be baked in an environment of 60°C for at least 4 hours, and then quickly transferred into the 25°C 100-class cleaning glove box described in (1) above for storage. (3) Assembling symmetrical batteries: Using the positive electrode plate as an electrode, five sets of symmetrical battery samples with different numbers of separator layers (1, 2, 3, 4, 5 layers) were assembled in the original position in the glove box described in (1) above. Each set of samples had five parallel samples. The pocket bags were side-sealed using a simple packaging machine, and liquid (300 μL) was poured into them using a pipette gun, and the bottoms were sealed. (4) Attaching a jig to the assembled symmetric battery: The assembled symmetric battery was placed in the glove box described in (1) above overnight so that the electrolyte could fully penetrate the separator. The next day, a metal jig was attached and the pressure of the jig was controlled to 0.7 MPa. (5) Electrochemical Impedance Spectroscopy (EIS) Measurement: Before the measurement, the symmetric batteries with different numbers of separator layers were placed in a high / low temperature box and kept at a constant temperature of 25°C for half an hour, and then the EIS was measured at the set temperature (25°C). (At a low temperature (e.g., -25°C to 0°C), the constant temperature time could be extended, for example, by about 2 hours.) (6) The French Bio-Logic VMP3 electrochemical operating station is used, with voltage <5V, current <400mA, and current accuracy: 0.1%*100μA. During the measurement, the EIS measurement conditions are set as follows: voltage frequency 1MHz-1kHz, external voltage 5MV, and jig pressure 0.7MPa. (7) Create a scattergram of the real part of the EIS data against the negative imaginary part, and plot the data of parallel samples with different and the same number of layers on one graph. Compare the resulting EIS diagram with the raw EIS data. (8) A new EIS diagram was obtained by removing all points outside the first quadrant from the EIS diagram obtained in (7) above. A linear fit was then performed on the plot in the first quadrant of the new EIS diagram to obtain a related equation. By setting y = 0, the x value was obtained, which is the resistance value of the separator with the required electrolyte. By analogy, the resistance value between parallel samples with different layer numbers can be obtained by linearly fitting the measured EIS data.

[0214] 5. Battery performance evaluation Cycle performance test: Five batteries from each set were taken out and repeatedly charged and discharged according to the following steps, and the cycle capacity retention rate of the batteries at 25°C or 45°C was calculated.

[0215] The secondary batteries manufactured in the examples and comparative examples were fixed in place with three steel jigs at 25°C, with a 1 mm single-sided insulating pad between the jigs and the batteries. A biasing force of 0.1 MPa was applied, and the first charge / discharge cycle was performed. The batteries were charged at a constant current and constant voltage of 0.7 C (i.e., the current value that completely releases the theoretical capacity within 2 hours) until the upper limit voltage reached 4.4 V, and then discharged at a constant current of 0.5 C until the final voltage reached 3 V. The discharge capacity of the first cycle was recorded, and then 1000 charge / discharge cycles were performed. The discharge capacity of the 1000th cycle was recorded. Cycle capacity retention = (discharge capacity at the 1000th cycle / discharge capacity at the first cycle) × 100%.

[0216] The secondary batteries manufactured in the examples and comparative examples were fixed in place with three steel jigs at 45°C, with a 1mm one-sided insulating pad between the jigs and the batteries. A biasing force of 0.1 MPa was applied, and the first charge / discharge cycle was performed. The batteries were charged at a constant current and constant voltage of 0.7C (i.e., the current value that completely releases the theoretical capacity within 2 hours) until the upper limit voltage reached 4.4V. They were then discharged at a constant current of 0.5C until the final voltage reached 3V. The discharge capacity of the first cycle was recorded, and then 1000 charge / discharge cycles were performed. The discharge capacity of the 1000th cycle was recorded. Cycle capacity retention = (discharge capacity at the 1000th cycle / discharge capacity at the first cycle) × 100%.

[0217] Table 8 shows the separator and battery performance data obtained by measurement for Examples 1-60 and Comparative Examples 1-3.

[0218] [Table 8] TIFF0007729919000031.tif247168TIFF0007729919000032.tif245168TIFF0007729919000033.tif138168

[0219] As can be seen from Table 8, the adhesive strength of the separator to the positive electrode plate in Example 1-60 at 25°C and 7 MPa was between 0.3 N / m and 2.3 N / m, the adhesive strength of the separator to the negative electrode plate in Example 1-60 at 25°C and 7 MPa was between 0.1 N / m and 0.9 N / m, the adhesive strength of the separator to the positive electrode plate in Example 1-60 at 95°C and 3 MPa was between 1 N / m and 4.8 N / m, and the adhesive strength of the separator to the negative electrode plate in Example 1-60 at 95°C and 3 MPa was between 1 N / m and 4.8 N / m. The adhesive strength between the separator and the negative electrode plate was between 0.4 N / m and 2.0 N / m, and the resistance of the separators in Examples 1-60 was less than 2.5 Ω. The cycle capacity retention rates of the batteries in Examples 1-60 were all better than those of Comparative Examples 1-3, which indicated that the adhesive strength between the separator and the electrode plate used in the present application was appropriate and the resistance was relatively low, thereby improving the dynamic performance and safety performance of the battery.

[0220] Finally, it should be noted that the above embodiments are merely intended to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art may still modify the technical solutions described in the above embodiments or make equivalent substitutions for some or all of the technical features therein. However, it should be understood that such modifications or substitutions do not depart from the essence of the relevant technical solution within the scope of the technical solution of the embodiments of the present application, and should all be included within the scope of the claims and description of the present application. In particular, as long as there is no structural conflict, the technical features of each paragraph mentioned in each embodiment may be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims. [Explanation of symbols]

[0221] 1 Secondary battery 2 Battery Module 3 Battery pack 4 Upper housing 5 Lower housing

Claims

1. A separator, A substrate; a pressure-sensitive coating formed on at least a portion of the substrate; The pressure-sensitive coating includes composite particles and a first plasticizer, the composite particles forming protrusions on the surface of the pressure-sensitive coating, the composite particles including polyacrylate particles and inorganic particles, and the inorganic particles are disposed between at least two of the polyacrylate particles, and the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles is 0.3 MPa. １／２ -4 MPa １／２ That is, the separator.

2. The first plasticizer includes an ester-based compound, and the solubility parameter of the ester-based compound is 12 MPa. １／２ -30 MPa １／２ The separator according to claim 1 ,

3. 3. The separator of claim 2, wherein the pressure sensitive coating further comprises an emulsifier, the emulsifier comprising at least one of an anionic emulsifier and a nonionic emulsifier.

4. 4. The separator of claim 3, wherein the pressure-sensitive coating comprises 80 to 96 parts by weight of composite particles, 5 to 30 parts by weight of an ester-based compound, and 0.1 to 0.5 parts by weight of an emulsifier.

5. 2. The separator of claim 1, wherein the composite particles have a Dv50 of ≥ 2.5 μm.

6. The separator according to claim 1 , wherein the composite particle comprises a first agglomerate, and the first agglomerate comprises at least two of the inorganic particles.

7. The separator according to claim 6, wherein 0.01 μm≦Dv50 of the first agglomerates≦Dv10 of the composite particles.

8. The separator according to claim 1 , wherein the composite particles comprise inorganic particles in the form of primary particles.

9. The separator according to claim 8, wherein the inorganic particles in the form of primary particles have a Dv50 of 0.01 μm to 1 μm.

10. The separator of claim 1 , wherein the composite particles include second agglomerates, and the second agglomerates include at least two of the polyacrylate particles.

11. The separator according to claim 10, wherein the Dv50 of the second aggregate is 0.3 μm to 5 μm.

12. The separator according to claim 1 , wherein the polyacrylate particles include polyacrylate particles in the form of primary particles and / or polyacrylate particles in the form of secondary particles.

13. The separator according to claim 12, wherein the Dv50 of the polyacrylate particles in primary particle form is 50 nm to 400 nm.

14. The separator according to claim 12, wherein the polyacrylate particles in the secondary particle form have a Dv50 of 2 μm to 15 μm.

15. 2. The separator of claim 1, wherein the polyacrylate particles have a vitrification transition temperature of 20°C to 80°C.

16. The separator according to claim 1 , wherein the content of the inorganic particles in the composite particles is 1 wt % to 50 wt %.

17. The separator according to claim 1 , wherein the height of each of the protrusions on both sides is 15 μm to 60 μm.

18. 10. The separator of claim 1, wherein the pressure sensitive coating further comprises 4 parts by weight to 20 parts by weight of a pressure sensitive adhesive polymer, the pressure sensitive adhesive polymer comprising an adhesive polymer and a second plasticizer.

19. 20. The separator of claim 18, wherein the adhesive polymer has an average particle size of 0.5 μm-3.0 μm.

20. 20. The separator of claim 18, wherein the pressure sensitive adhesive polymer has a DSC melting point of -50°C to 100°C.

21. 20. The separator of claim 18, wherein the weight ratio of the adhesive polymer to the second plasticizer is (4-19):

1.

22. the pressure-sensitive adhesive polymer has a core-shell structure, and the core and shell of the core-shell structure both comprise an adhesive polymer and a second plasticizer; wherein the weight ratio of the adhesive polymer to the second plasticizer in the core structure is (2-5):1; 20. The separator of claim 18, wherein the mass ratio of the adhesive polymer to the second plasticizer in the shell structure is (6-10):

1.

23. The adhesive polymer comprises a copolymer formed by the reaction monomers of at least one of the following first monomers, at least one of the second monomers, at least one of the third monomers, and at least one reactive dispersant: First monomer: acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylol acrylamide, acrylamide, styrene, acrylonitrile; Second monomers include C4-C22 alkyl acrylates, isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl (isooctyl) acrylate, cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, ethylene urea ethyl methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, ethylene urea ethyl methacrylate, acrylic methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate; Third monomer: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, 3-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethyl (meth)acrylamide, diacetone acrylamide, methacrylic acid, ethyl acetoacetate, divinylbenzene, an epoxy resin having an epoxy value of 0.35-0.50, and divinylbenzene; 20. The separator of claim 18, comprising reactive dispersants: polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, polyvinyl alcohol.

24. 20. The separator of claim 18, wherein the second plasticizer comprises at least one of a glycerol C4-C10 alkyl diether, a glycerol C4-C10 alkyl monoether, a glycerol C4-C10 carboxylic acid monoester, a glycerol C4-C10 carboxylic acid diester, a propylene glycol C4-C10 alkyl monoether, and glycerol.

25. 2. The separator according to claim 1, wherein the pressure-sensitive coating further comprises organic particles, the organic particles comprising at least one of polytetrafluoroethylene particles, polytrifluorochloroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of fluorine-containing alkenyl monomer units and ethylene monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylate monomer units, and modified compound particles of any of the above homopolymers or copolymers, and the organic particles and the composite particles form the protrusions on the coating surface.

26. The separator of claim 25 , wherein the organic particles form third aggregates.

27. 27. The separator of claim 26, wherein the Dv50 of the third aggregate is 5 μm-30 μm.

28. The separator according to claim 26, wherein the third aggregate contains organic particles in the form of primary particles, and there is a gap between two adjacent organic particles.

29. The separator according to claim 28, wherein the Dv50 of the organic particles in the form of primary particles is 50 nm to 400 nm.

30. The separator according to claim 25, wherein the mass ratio of the composite particles to the organic particles is (20-90):(0-70).

31. 10. The separator of claim 1, wherein the pressure sensitive coating has an average thickness of 2 μm-20 μm.

32. 2. A method for manufacturing a separator according to claim 1, comprising forming a pressure-sensitive coating on at least a portion of a surface of a substrate, the pressure-sensitive coating comprising polyacrylate particles and a first plasticizer, the composite particles forming protrusions on a surface of the pressure-sensitive coating, the composite particles comprising polyacrylate particles and inorganic particles, the inorganic particles being disposed between at least two of the polyacrylate particles, and the absolute value of the difference between the solubility parameter of the first plasticizer and the solubility parameter of the composite particles being 0.3 MPa. １／２ -4 MPa １／２ The method for manufacturing a separator is as follows.

33. A battery comprising the separator of any one of claims 1 to 31.

34. 34. A power consuming device comprising the battery of claim 33, the battery being adapted to provide electrical energy.

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