Separator, secondary battery cell, battery device, and electric device

Abstract

Provided are a separator, a secondary battery cell, a battery device, and an electric device. The secondary battery cell comprises a positive electrode sheet, a negative electrode sheet, and a separator; the separator is arranged between the positive electrode sheet and the negative electrode sheet; the separator comprises a porous base film and a coating located on at least one side of the porous base film; the coating comprises organic particles; and after the organic particles are immersed in a mixed solvent containing ethylene carbonate and ethyl methyl carbonate according to a volume ratio of 3:7 at a constant temperature of 60°C for 7 days, the swelling degree of the organic particles is less than or equal to 3%. The secondary battery cell has high mass energy density, low internal resistance, and good kinetics performance.

Description

Separator, secondary battery cell, battery device, and power consuming device

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202410946468.3, filed on July 15, 2024, entitled “Separator, battery cell and power consuming device” and Chinese Patent Application No. 202411383460.7, filed on September 30, 2024, entitled “Separator, secondary battery cell, battery device, and power consuming device”, the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0003] The present disclosure relates to a separator, a secondary battery cell, a battery device, and a power consuming device. BACKGROUND

[0004] With the increasingly wide range of applications of secondary battery cells, people’s demand for the use of secondary battery cells is also increasing, such as the increasingly high requirements for the energy density, kinetic performance, and reliability of secondary battery cells. Therefore, how to make the secondary battery cell have higher energy density and good kinetic performance under the premise of high reliability is a technical problem to be solved at present. SUMMARY

[0005] The present disclosure provides a separator, a secondary battery cell, a battery device, and a power consuming device, the secondary battery cell has high mass energy density, low internal resistance, and good kinetic performance.

[0006] In a first aspect, the present disclosure provides a secondary battery cell, comprising a positive electrode sheet, a negative electrode sheet, and a separator, the separator is arranged between the positive electrode sheet and the negative electrode sheet, the separator comprises a porous base film and a coating layer arranged on at least one side of the porous base film, the coating layer comprises organic particles, and the swelling degree of the organic particles in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 is less than or equal to 3% when the organic particles are soaked in the mixed solvent at 60°C for 7 days.

[0007] The secondary battery cell using the organic particles with small density can have higher mass energy density. The organic particles in the coating layer of the separator of the present disclosure have a swelling degree of less than or equal to 3% in the organic solvent, and the structure stability of the organic particles is high during the long-term use of the secondary battery cell, thereby improving the problem of the decrease of the air permeability of the separator during use. The separator has good air permeability, the secondary battery cell has low internal resistance and good kinetic performance. Therefore, the separator of the present disclosure can make the secondary battery cell have high mass energy density, low internal resistance, and good kinetic performance.

[0008] In some embodiments, the organic particles have a swelling degree of less than or equal to 2.5% when immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days.

[0009] Thus, the internal resistance of the secondary battery cell can be further reduced, and the kinetic performance of the secondary battery cell can be improved.

[0010] In some embodiments, the organic particles have a true density of 1.0 g / cm 3 -2.0 g / cm 3 ; and optionally 1.0 g / cm 3 -1.8 g / cm 3 .

[0011] In some embodiments, the organic particles have a volume distribution particle size Dv50 of less than 1 μm, and optionally 50 nm-850 nm.

[0012] In some embodiments, the organic particles are at least one of a thermosetting resin polymer or a cross-linked polymer.

[0013] In some embodiments, the organic particles are amorphous polymers.

[0014] In some embodiments, the organic particles have no melting point.

[0015] The organic particles of the present disclosure have no melting point, indicating that the organic particles have good heat resistance and thermal stability, and thus can better resist thermal shrinkage of the porous base film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0016] In some embodiments, the organic particles include one or more of a phenolic resin-based organic particle, a polymer particle containing a triazine ring structural unit, a cross-linked styrene-based organic particle, and a silicon-containing organic resin particle.

[0017] In some embodiments, the phenolic resin-based organic particle is a thermosetting resol polymer.

[0018] In some embodiments, the phenolic resin-based organic particle has no glass transition temperature below 300°C.

[0019] In some embodiments, the phenolic resin-based organic particle has a volume distribution particle size Dv50 of 220 nm-850 nm.

[0020] In some embodiments, the polymer particle containing a triazine ring structural unit includes a bridging structure connecting the triazine ring structural units. Optionally, the bridging structure includes one or a combination of two or more of an alkylene group, an alkylene ether group, an alkylene amine group, an ester group, and an amide group.

[0021] In some embodiments, the triazine ring structural unit of the polymer particles containing a triazine ring structural unit further has a substituent thereon, the substituent comprising a combination of one or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, a hydroxyl group, a halogen.

[0022] In some embodiments, the polymer particles containing a triazine ring structural unit comprise at least one of melamine formaldehyde polymers and derivatives thereof, etherified melamine formaldehyde polymers and derivatives thereof, etherified melamine formaldehyde-polyol polymers and derivatives thereof, etherified melamine formaldehyde-polybasic acid polymers and derivatives thereof, etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof.

[0023] In some embodiments, the melamine formaldehyde polymers and derivatives thereof comprise one or more of melamine formaldehyde, phenylated melamine formaldehyde, melamine-phenylated melamine formaldehyde, melamine-(2,4-diamino-1,3,5-triazine) formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine) formaldehyde, trihydrazino-s-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde.

[0024] In some embodiments, the etherified melamine formaldehyde polymers and derivatives thereof comprise one or more of methyl-etherified melamine formaldehyde, butyl-etherified melamine formaldehyde, methyl-etherified phenylated melamine formaldehyde, butyl-etherified phenylated melamine formaldehyde.

[0025] In some embodiments, the etherified melamine formaldehyde-polyol polymers and derivatives thereof comprise one or more of methyl-etherified melamine formaldehyde-ethylene glycol polymer, methyl-etherified melamine formaldehyde-1,2-propanediol polymer, methyl-etherified melamine formaldehyde-1,4-butanediol polymer, methyl-etherified melamine formaldehyde-polyester polyol polymer, methyl-etherified melamine formaldehyde-polyvinyl alcohol polymer, butyl-etherified melamine formaldehyde-ethylene glycol polymer, butyl-etherified melamine formaldehyde-1,2-propanediol polymer, butyl-etherified melamine formaldehyde-1,4-butanediol polymer, butyl-etherified melamine formaldehyde-polyester polyol polymer.

[0026] In some embodiments, the etherified melamine aldehyde-polycarboxylic acid polymer and derivatives thereof include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malic acid polymer, a methyl etherified melamine formaldehyde-succinic acid polymer, a methyl etherified melamine formaldehyde-citric acid polymer, a methyl etherified melamine formaldehyde-terephthalic acid polymer, a methyl etherified melamine formaldehyde-phthalic acid polymer, a butyl etherified melamine formaldehyde-oxalic acid polymer, a butyl etherified melamine formaldehyde-malic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, and a butyl etherified melamine formaldehyde-phthalic acid polymer.

[0027] In some embodiments, the etherified melamine aldehyde-polycarboxylic acid polymer and derivatives thereof include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malic acid polymer, a methyl etherified melamine formaldehyde-succinic acid polymer, a methyl etherified melamine formaldehyde-citric acid polymer, a methyl etherified melamine formaldehyde-terephthalic acid polymer, a methyl etherified melamine formaldehyde-phthalic acid polymer, a butyl etherified melamine formaldehyde-oxalic acid polymer, a butyl etherified melamine formaldehyde-malic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, and a butyl etherified melamine formaldehyde-phthalic acid polymer.

[0028] In some embodiments, the polymer particles containing triazine ring structural units have no glass transition temperature below 300°C.

[0029] In some embodiments, the polymer particles containing triazine ring structural units have a volume distribution particle size Dv50 of 220 nm to 850 nm.

[0030] In some embodiments, the crosslinked styrene-based organic particles include styrene or styrene derivative structural units and crosslinking structural units.

[0031] Optionally, the styrene or styrene derivative structural units include one or more of a styrene structural unit, a 1-methyl-1-styrene structural unit, a 4-methylstyrene structural unit, a 2-methylstyrene structural unit, a 2,4-dimethylstyrene structural unit, and a 2,5-dimethylstyrene structural unit.

[0032] Optionally, the crosslinking structural units include one or more of a divinylbenzene structural unit, a diethylene glycol dimethacrylate structural unit, a pentaerythritol tetraacrylate structural unit, a 1,4-butanediol diacrylate structural unit, a 1,6-hexanediol diacrylate structural unit, a 1,8-octanediol diacrylate structural unit, a trimethylolpropane triacrylate structural unit, a pentaerythritol trimethacrylate structural unit, a tetraethylene glycol dimethacrylate structural unit, a tripropylene glycol diacrylate structural unit, a N,N-methylenebisacrylamide structural unit, a N,N'-vinylbisacrylamide structural unit, and a 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit.

[0033] In some embodiments, the glass transition temperature Tg of the crosslinked styrene-based organic particles is 114°C to 158°C. g is 114°C to 158°C.

[0034] In some embodiments, the volume distribution particle size Dv50 of the crosslinked styrene-based organic particles is 86 nm to 300 nm.

[0035] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles contain carbon-carbon bonds and siloxane structures.

[0036] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles are network structures formed with carbon-carbon bonds as the main chain, and side chains containing siloxane structures.

[0037] In some embodiments, the silicon-containing organic crosslinked resin particles include crosslinking structure units.

[0038] Optionally, the crosslinking structure units include one or more of divinylbenzene structure units, diethylene glycol divinyl ether structure units, triethylene glycol divinyl ether structure units, maleic acid diallyl ester structure units, ethylene glycol dimethacrylate structure units, 1,4-butanediol diacrylate structure units, 1,6-hexanediol diacrylate structure units, 1,8-octanediol diacrylate structure units, trimethylolpropane triacrylate structure units, pentaerythritol trimethacrylate structure units, tetraethylene glycol dimethacrylate structure units, tripropylene glycol diacrylate structure units, 2,2,4-trimethyladipoyl bis[2-ethylaziridine] structure units, 1,1-nonanedioyl bis[2-methylaziridine] structure units, 1,1-(1,3-phenylenedicarbonyl) bis[2-methylaziridine] structure units, trimethylolpropane tris(2-methyl-1-aziridinyl propionate) structure units, trimethylolpropane-tris[3-(2-methylaziridinyl) propionate] structure units, pentaerythritol tris(3-aziridinyl) propionate structure units.

[0039] In some embodiments, the silicon-containing organic resin particles have no glass transition temperature below 300°C.

[0040] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles is 86 nm to 300 nm.

[0041] In some embodiments, the ratio of the volume distribution particle size Dv50 of the organic particles to the average pore size of the porous base membrane is greater than or equal to 1.1.

[0042] In some embodiments, the coating further comprises a binder.

[0043] In some embodiments, the mass content of the organic particles is 50%-99% based on the total mass of the coating.

[0044] In some embodiments, the thickness of the coating is 0.5 μm-5 μm.

[0045] In some embodiments, the areal density of the coating is 0.45 g / m 2 -5 g / m 2 .

[0046] In some embodiments, the gas permeability of the separator film is 160 s / 100 ml-230 s / 100 ml.

[0047] In a second aspect, the present disclosure provides a battery device comprising a plurality of the secondary battery cells of the first aspect of the present disclosure.

[0048] In a third aspect, the present disclosure provides a power consumption device comprising the secondary battery cell of the first aspect of the present disclosure or the battery device of the second aspect of the present disclosure.

[0049] In a fourth aspect, the present disclosure provides a separator film comprising a porous base film and a coating layer on at least one side of the porous base film, wherein the coating layer comprises organic particles, and the swelling degree of the organic particles in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

[0050] In some embodiments, the true density of the organic particles is 1.0 g / cm 3 -2.0 g / cm 3 ; optionally 1.0 g / cm 3 -1.8 g / cm 3 .

[0051] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, optionally 50 nm-850 nm.

[0052] In some embodiments, the organic particles are at least one of thermosetting resin polymers or cross-linked polymers.

[0053] In some embodiments, the organic particles are amorphous polymers.

[0054] In some embodiments, the organic particles have no melting point.

[0055] In some embodiments, the organic particles include one or more of phenol resin-based organic particles, polymer particles containing triazine ring structural units, crosslinked styrene-based organic particles, and silicon-containing organic resin particles. BRIEF DESCRIPTION OF DRAWINGS

[0056] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required to be used in the embodiments of the present disclosure will be briefly introduced below. Obviously, the drawings described below are only some of the embodiments of the present disclosure, and other drawings can also be obtained according to the drawings without creative labor for those skilled in the art.

[0057] FIG. 1 shows a schematic diagram of a secondary battery cell according to some embodiments of the present disclosure.

[0058] FIG. 2 shows a schematic diagram of an electric device according to some embodiments of the present disclosure.

[0059] In the drawings, the drawings are not necessarily drawn according to the actual scale. DETAILED DESCRIPTION

[0060] Hereinafter, specific embodiments of the present disclosure, i.e., a separator, a secondary battery cell, a battery device, and an electric device will be specifically described with appropriate reference to the drawings. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there will be cases where detailed descriptions of matters known well, repeated descriptions of substantially the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided in order for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0061] The ranges disclosed herein are defined by their lower and upper endpoints, given that a range is defined by selecting a lower endpoint and an upper endpoint, the selected lower and upper endpoints define the boundaries of the particular range. Ranges defined by endpoints can be either inclusive or exclusive of the endpoints, and can be arbitrarily combined, i.e., any lower endpoint can be combined with any upper endpoint to form a range. For example, if ranges of 60-120 and 80-110 are listed, it is understood that ranges of 60-110 and 80-120 are also contemplated. Also, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present disclosure, unless otherwise stated, a numerical range "a-b" indicates a shorthand way of describing all of the individual real combinations that fall between "a" and "b", where "a" and "b" are both real numbers. For example, the numerical range "0-5" indicates that all of the real numbers between "0" and "5" have been listed herein, and "0-5" is merely a shorthand way of describing those numerical combinations. In addition, when a parameter is stated to be an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0062] Unless otherwise specified, all embodiments and optional embodiments of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0063] Unless otherwise specified, all technical features and optional technical features of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0064] Unless otherwise specified, all steps of the present disclosure can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0065] Unless otherwise specified, in the present disclosure, the terms "first", "second", etc. are used to distinguish different objects, and are not used to describe a particular order or primary and secondary relationship.

[0066] In the present disclosure, the terms "a plurality of", "a plurality of" refer to two or more.

[0067] In the description of the embodiments of the present disclosure, if there is no special indication, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature can be "above", "over" and "on" the second feature, which can be that the first feature is directly above or obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature can be "below", "under" and "under" the second feature, which can be that the first feature is directly below or obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0068] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25°C.

[0069] The secondary battery cell mentioned in the embodiments of the present disclosure can realize the function of charging and discharging independently, and can continue to be used by activating the active material through charging after discharging. The secondary battery cell can be in the shape of a cylinder, a cuboid or other shapes, which are not limited in the embodiments of the present disclosure. As shown in FIG. 1, the secondary battery cell 5 is a cuboid structure as an example.

[0070] The secondary battery cell provided by the embodiments of the present disclosure can include but is not limited to lithium battery cells, sodium battery cells, such as lithium ion battery cells, sodium ion battery cells, lithium metal battery cells, sodium metal battery cells, etc.

[0071] The secondary battery cell provided by the embodiments of the present disclosure includes an electrode assembly. The electrode assembly can be a winding structure or a stacking structure, which is not limited in the embodiments of the present disclosure. The secondary battery cell further includes an outer package, which can be used to package the electrode assembly. The outer package can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT) and polybutylene succinate (PBS).

[0072] The battery apparatus mentioned in the embodiments of the present disclosure can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of secondary battery cells connected in series, in parallel or in a mixed manner through a busbar component.

[0073] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of secondary battery cells.

[0074] As an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of secondary battery cells.

[0075] In some embodiments, the battery device can be a battery pack, which includes a case and one or more battery cell assemblies, the battery cell assemblies being accommodated in the case.

[0076] As an example, the battery cell assembly can be a battery module, which can be accommodated in the case by fixing the battery module in the case.

[0077] As an example, the battery cell assembly can also be accommodated in the case by directly fixing a plurality of secondary battery cells in the case.

[0078] As an example, the case can include a first case and a second case. The first case and the second case are fastened so that an enclosed space is formed inside the case to accommodate the battery cell assembly. Here, the enclosed means covered or closed, which can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0079] As an example, the case can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected to the frame, respectively, so that an enclosed space is formed inside the case to accommodate the battery cell assembly.

[0080] In some embodiments, the case can be part of a chassis structure of a vehicle. For example, part of the case can be at least part of a floor of the vehicle, or part of the case can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0081] The technical solutions described in the embodiments of the present disclosure are applicable to various electric devices using secondary battery cells and battery devices, such as mobile devices (e.g., mobile phones, tablet computers, notebook computers, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. The secondary battery cells and the battery devices are used to store or provide electric energy.

[0082] FIG. 2 is a schematic diagram of an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0083] In the context of the present disclosure, the organic particles mainly play a role in improving heat resistance in the coating layer of the separator film, and almost have no adhesion.

[0084] The separator film is an important component for supporting the secondary battery cell to complete the charge and discharge electrochemical process. The commonly used separator film is mostly polyolefin material, but the glass transition temperature of this kind of material is low, and serious thermal shrinkage will occur after heating. In order to improve the heat resistance of the separator film, boehmite or alumina is commonly used as a heat-resistant filler and a binder to form a coating. The density of boehmite and alumina is large, and the mass of boehmite and alumina is greater than that of other materials under the same packing volume, which affects the energy density of the secondary battery cell.

[0085] The separator film provided by the embodiments of the present disclosure can make the secondary battery cell have high mass energy density, low internal resistance and good kinetic performance.

[0086] The separator film provided by the embodiments of the present disclosure comprises a porous base film and a coating layer located on at least one side of the porous base film, and the coating layer comprises organic particles and a binder. The swelling degree of the organic particles in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 and soaked at 60°C for 7 days is less than or equal to 3%.

[0087] The porous base film and the coating layer both have a pore structure, so that the separator film has good air permeability and facilitates the passage of ions. The organic particles in the coating layer are connected to each other and fixed by the binder, and the gap between the organic particles can form a pore structure.

[0088] The density of the organic particles is small, and the secondary battery cell using the same can have higher mass energy density.

[0089] The electrolyte needs to be added during the preparation of the secondary battery cell, and the electrolyte comprises an electrolyte salt and an organic solvent. The swelling behavior of the organic particles in the electrolyte is dominated by the ion energy, and the swelling behavior of the organic particles in the organic solvent is more significantly affected by the mixing energy. In addition, the organic solvent molecules are small and easy to enter the molecular chain segments of the heat-resistant organic particles and swell the unstable parts. At present, the swelling degree of the conventional organic particles in the organic solvent is large, and the swelling degree of the organic particles in the coating layer is large, which can cause the air permeability of the separator film to decrease during the use of the secondary battery cell, and the internal resistance of the secondary battery cell increases. The swelling degree of the organic particles in the coating layer of the separator film of the present disclosure is less than or equal to 3%, and the structure stability of the organic particles is high during the long-term use of the secondary battery cell, thereby improving the problem of the decrease in the air permeability of the separator film during use. The air permeability of the separator film is good, the internal resistance of the secondary battery cell is small, and the kinetic performance is good.

[0090] Therefore, the separator film of the embodiments of the present disclosure can make the secondary battery cell have high mass energy density, low internal resistance and good kinetic performance.

[0091] In some embodiments, the swelling degree of the organic particles in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days can be less than or equal to 2.5%, less than or equal to 2%, less than or equal to 1.8%, or less than or equal to 1.5%.

[0092] Thus, the internal resistance of the secondary battery cell can be further reduced, and the kinetic performance of the secondary battery cell can be improved.

[0093] The swelling degree = (the mass of the organic particles after immersion - the initial mass of the organic particles) / the initial mass of the organic particles x 100%.

[0094] The swelling degree of the organic particles can be tested as follows: take an appropriate amount of sample (for example, about 1 g), and record the mass as m1. Place the sample in a semi-permeable membrane sample bag, seal the bag, and the sample bag can permeate the solvent but cannot permeate the sample. Soak the sample bag in an appropriate amount of solvent (for example, about 50 g) at 60°C for 7 days. Then take out the sample bag, take out the sample from the sample bag, wipe off the excess solvent, and weigh the mass of the sample again as m2. The swelling degree = (m2 - m1) / m1 x 100%. The solvent is a mixed solvent obtained by mixing ethylene carbonate (EC) and methyl ethyl carbonate (EMC) in a volume ratio of 3:7.

[0095] In some embodiments, the true density of the organic particles can be 1.0 g / cm 3 -2.0 g / cm 3 . Alternatively, the true density of the organic particles can be 1.0 g / cm 3 -1.8 g / cm 3 .

[0096] Currently, the true density of inorganic particles such as boehmite and aluminum oxide is usually 2.5 g / cm 3 -3.5 g / cm 3 . The true density of the organic particles of the present disclosure is small, so that the secondary battery cell using the separator film of the present disclosure has a higher mass energy density.

[0097] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, and can be 50 nm-850 nm or 86 nm-850 nm.

[0098] The organic particles of the present disclosure are neither soluble in water nor in organic solvents such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), and chloroform at 25°C, i.e., they are not soluble in the mobile phase for gel permeation chromatography testing, and the molecular weight of the organic particles cannot be tested by gel permeation chromatography.

[0099] The organic particle of the present disclosure is at least one of a thermosetting resin polymer or a crosslinked polymer.

[0100] The thermosetting resin polymer refers to a polymer product that hardens irreversibly when cured, and does not soften or melt upon heating once cured.

[0101] The crosslinked polymer refers to a polymer product obtained when a crosslinking bond is formed between monomer units.

[0102] The organic particle of the present disclosure is an amorphous polymer.

[0103] In some embodiments, the organic particle has no melting point.

[0104] The organic particle of the present disclosure has no melting point, indicating that the organic particle has good heat resistance and thermal stability, and thus can better resist thermal shrinkage of the porous base film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0105] The melting point can be tested according to the following method: take an appropriate amount of sample (e.g., 5 mg-15 mg) and place it in a differential scanning calorimeter (DSC) crucible, shake it flat, and cover it with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60 mL / min, protective gas 20 mL / min; program settings: temperature increase from 25°C to 200°C at a rate of 10°C / min, hold for 5 min to eliminate thermal history, temperature decrease from 200°C to -40°C at a rate of 10°C / min, and temperature increase from -40°C to 300°C at a rate of 10°C / min. Determine whether the organic particle has a melting point below 300°C by the DSC curve.

[0106] The organic particle has no melting point, meaning that the DSC curve of the organic particle has no melting peak.

[0107] In some embodiments, the organic particle can include one or more of a phenolic resin-based organic particle, a polymer particle containing a triazine ring structure unit, a crosslinked styrene-based organic particle, and a silicon-containing organic resin particle.

[0108] [Phenolic resin-based organic particle]

[0109] In some embodiments, the phenolic resin-based organic particle is a thermosetting resin polymer.

[0110] In some embodiments, the phenolic resin-based organic particle is a thermosetting resol polymer.

[0111] The raw material of the phenolic resin-based organic particles can include a phenolic compound and an aldehyde compound. In some embodiments, the phenolic compound can include one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cardanol. In some embodiments, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0112] In some embodiments, the phenolic resin-based organic particles have no glass transition temperature below 300℃.

[0113] The phenolic resin-based organic particles have no glass transition temperature below 300℃, which indicates that the organic particles have good heat resistance and thermal stability, and thus can better resist the thermal shrinkage of the porous base film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0114] In some embodiments, the volume distribution particle size Dv50 of the phenolic resin-based organic particles can be 220nm-850nm.

[0115] The volume distribution particle size Dv50 of the polymer particles of the phenolic resin-based organic particles is within the above range, which is conducive to the separator film having good heat resistance and air permeability.

[0116] The resol-based material generally has a large swelling degree in an organic solvent, which cannot meet the requirements of the separator film. Based on this, the present disclosure provides a phenolic resin-based organic particle, which has a swelling degree of less than or equal to 3% when soaked in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate at a volume ratio of 3:7 at 60℃ for 7 days. The present disclosure also provides a method for preparing the phenolic resin-based organic particle.

[0117] In some embodiments, the method for preparing the phenolic resin-based organic particle includes the following steps: providing a resol-based material; curing the resol-based material at a first temperature and in a first atmosphere for a first time, then curing the resol-based material at a second temperature and in a second atmosphere for a second time, and then crushing to obtain the phenolic resin-based organic particle. The first temperature is 115℃-180℃, and the second temperature is 210℃-290℃.

[0118] The existing curing process of the resol-based material is often carried out at room temperature or at a temperature of 150℃ or below. The above curing method cannot fully cure the resol-based material, which results in the obtained phenolic resin-based organic particle still having a large swelling degree. The present disclosure adjusts the temperature of the segmented curing of the resol-based material, and obtains the phenolic resin-based organic particle with good heat resistance and small swelling degree.

[0119] The preparation method provided by the embodiments of the present disclosure has simple process and does not need complex operation, and therefore has low production cost.

[0120] The phenolic resin-based organic particles prepared by the present disclosure are thermosetting resol polymers.

[0121] The first temperature can be 115-180℃, for example, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, or a range formed by any of the above values.

[0122] The first temperature in the above range can make the curing of the resol resin-based material in the first stage more uniform and sufficient, so that the phenolic resin-based organic particles with smaller swelling degree can be obtained.

[0123] Alternatively, the first temperature can be 120-175℃, 120-170℃.

[0124] The second temperature can be 210-290℃, for example, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, or a range formed by any of the above values.

[0125] The second temperature in the above range can make the curing of the phenolic resin-based organic particles more sufficient and the swelling degree smaller while avoiding denaturation (such as degradation) of the phenolic resin-based organic particles.

[0126] Alternatively, the second temperature can be 225-290℃, 225-280℃, 235-290℃, 235-280℃.

[0127] In some embodiments, the first time can be 1-4h, for example, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, or a range formed by any of the above values.

[0128] The first time in the above range can make the curing of the resol resin-based material in the first stage more uniform and sufficient, so that the phenolic resin-based organic particles with smaller swelling degree can be obtained.

[0129] In some embodiments, the second time can be 2h-6h, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, or any range of the above values.

[0130] Within the above-mentioned time range, phenolic resin organic particles can be cured more fully and have less swelling.

[0131] In some embodiments, the first atmosphere may be an inert gas atmosphere or an oxygen-containing atmosphere. An oxygen-containing atmosphere may include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere may be 5%-50%. Optionally, the inert gas may be one or more of nitrogen, argon, and helium, including but not limited to.

[0132] Optionally, the first atmosphere is an oxygen-containing atmosphere, wherein the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More preferably, the first atmosphere can be an air atmosphere.

[0133] In some embodiments, the second atmosphere may be an inert gas atmosphere or an oxygen-containing atmosphere. An oxygen-containing atmosphere may include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere may be 5%-50%. Optionally, the inert gas may be one or more of nitrogen, argon, and helium, including but not limited to.

[0134] Optionally, the second atmosphere is an oxygen-containing atmosphere, wherein the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More preferably, the second atmosphere can be an air atmosphere.

[0135] In some embodiments, the method for preparing phenolic resin organic particles may further include sieving and demagnetizing steps after crushing.

[0136] Amorphous phenolic resins are commercially available or synthesized using methods known in the art. In some embodiments, the preparation method of amorphous phenolic resins includes the following steps: reacting a phenolic compound and an aldehyde compound under the catalysis of an alkaline substance to obtain the amorphous phenolic resin.

[0137] Optionally, the alkaline substance may include one or more of ammonia, NaOH, and Na2CO3.

[0138] Optionally, phenolic compounds may include one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cashew nut shellol.

[0139] Optionally, aldehyde compounds may include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0140] [Polymer particles containing triazine ring structural units]

[0141] The polymer particles containing triazine ring structural units disclosed herein also include bridging structures connecting the triazine ring structural units.

[0142] Polymer particles containing triazine ring structural units have multiple triazine ring structural units in their molecular structure. The bridging structure refers to the groups that connect the triazine ring structural units, and the bridging structures may be the same or different.

[0143] Optionally, the bridging structure may include one or more of the following: alkylene, alkylene ether, alkylene amine, ester group, and amide group.

[0144] Alternatively, the bridging structure may include one or more of methylene, methylene ether, and methyleneamine.

[0145] In some embodiments, the triazine ring structural units of the polymer particles containing triazine ring structural units may also have substituents, which may include one or more combinations of alkyl, alkenyl, phenyl, cycloalkyl, amino, hydroxyl, and halogen.

[0146] In some embodiments, polymer particles containing triazine ring structural units may include at least one of the following: melamine aldehyde polymers and their derivatives, etherified melamine aldehyde polymers and their derivatives, etherified melamine aldehyde-polyol polymers and their derivatives, etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives, and etherified melamine aldehyde-polyamine amide polymers and their derivatives.

[0147] In some embodiments, melamine aldehyde polymers and their derivatives may include melamine formaldehyde polymers and their derivatives.

[0148] Optionally, melamine-formaldehyde polymers and their derivatives may include one or more of the following: melamine-formaldehyde, benzyl melamine-formaldehyde, melamine-benzene melamine-formaldehyde, melamine-(2,4-diamino-1,3,5-triazine)formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine)formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine)formaldehyde, trihydrazine-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine)formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine)formaldehyde.

[0149] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include etherified melamine formaldehyde polymers and their derivatives.

[0150] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include methyl etherified melamine aldehyde polymers and their derivatives, diethyl etherified melamine aldehyde polymers and their derivatives, butyl etherified melamine aldehyde polymers and their derivatives, and methyl-butyl mixed etherified melamine aldehyde polymers and their derivatives.

[0151] Optionally, the etherified melamine-formaldehyde polymers and their derivatives may include methyl etherified melamine-formaldehyde polymers and their derivatives, diethyl etherified melamine-formaldehyde polymers and their derivatives, butyl etherified melamine-formaldehyde polymers and their derivatives, and methyl-butyl mixed etherified melamine-formaldehyde polymers and their derivatives.

[0152] Etherified melamine aldehyde polymers and their derivatives may include one or more of partially etherified melamine aldehyde polymers and their derivatives, and fully etherified melamine aldehyde polymers and their derivatives. Optionally, etherified melamine aldehyde polymers and their derivatives may include fully etherified melamine aldehyde polymers and their derivatives.

[0153] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzyl melamine formaldehyde, and butyl etherified benzyl melamine formaldehyde.

[0154] Etherified melamine aldehyde-polyol polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polyol. Optionally, the molar ratio of etherified melamine aldehyde resin to polyol can be 1:2 to 1:6.

[0155] In some embodiments, the polyol may include one or more of diols, triols, and tetraols. Optionally, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethylbutyric acid, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyols, and polyester polyols. More preferably, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, polyvinyl alcohol, and polyester polyols.

[0156] Optionally, the polyester polyol may include one or more of the following: polyethylene adipate diol, 1,4-butanediol adipate diol, propylene adipate diol, neopentyl adipate diol, neopentyl adipate-1,6-hexanediol adipate diol, hexanediol adipate diol, polycarbonate diol, and polycaprolactone diol.

[0157] Optionally, the polyether polyol may include one or more of polyoxypropylene glycol, polyoxypropylene triol, and polytetrahydrofuran glycol.

[0158] Optionally, the molecular weight of the polyester polyol can be below 5000, and optionally below 2000.

[0159] Optionally, the molecular weight of the polyether polyol can be below 5000, and optionally below 2000.

[0160] Optionally, the molecular weight of polyvinyl alcohol can be below 5000, and optionally below 2000.

[0161] In some embodiments, the etherified melamine-formaldehyde-polyol polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-ethylene glycol polymer, methyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, methyl etherified melamine-formaldehyde-1,4-butanediol polymer, methyl etherified melamine-formaldehyde-polyester polyol polymer, methyl etherified melamine-formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine-formaldehyde-ethylene glycol polymer, butyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, butyl etherified melamine-formaldehyde-1,4-butanediol polymer, and butyl etherified melamine-formaldehyde-polyester polyol polymer.

[0162] Etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polycarboxylic acid. Optionally, the molar ratio of etherified melamine aldehyde resin to polycarboxylic acid can be 1:2 to 1:6.

[0163] In some embodiments, the polycarboxylic acid may include one or more of dicarboxylic acids, tricarboxylic acids, and tetracarboxylic acids. Optionally, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid. More preferably, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, and terephthalic acid.

[0164] In some embodiments, the etherified melamine-formaldehyde-polycarboxylic acid polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-oxalic acid polymer, methyl etherified melamine-formaldehyde-malonic acid polymer, methyl etherified melamine-formaldehyde-succinic acid polymer, methyl etherified melamine-formaldehyde-citric acid polymer, methyl etherified melamine-formaldehyde-phthalic acid polymer, butyl etherified melamine-formaldehyde-oxalic acid polymer, butyl etherified melamine-formaldehyde-malonic acid polymer, butyl etherified melamine-formaldehyde-citric acid polymer, butyl etherified melamine-formaldehyde-terephthalic acid polymer, and butyl etherified melamine-formaldehyde-phthalic acid polymer.

[0165] Etherified melamine aldehyde-polyamine amide polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polyamine amide. Optionally, the molar ratio of etherified melamine aldehyde resin to polyamine amide can be 1:2 to 1:6.

[0166] In some embodiments, the polyamide may include one or more of ethylene glycol, malonamide, succinamide, adipamide, and isophthalimide. Optionally, the polyamide may include one or more of ethylene glycol, malonamide, and isophthalimide.

[0167] In some embodiments, the etherified melamine-formaldehyde-polyamine amide polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-glyoxalamide polymer, methyl etherified melamine-formaldehyde-malonamide polymer, methyl etherified melamine-formaldehyde-isophthalimide polymer, and butyl etherified melamine-formaldehyde-glyoxalamide polymer.

[0168] In some embodiments, polymer particles containing triazine ring structural units have no glass transition temperature below 300°C.

[0169] Polymer particles containing triazine ring structural units have no glass transition temperature below 300℃, indicating that the organic particles have good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0170] In some embodiments, the volume distribution particle size Dv50 of polymer particles containing triazine ring structural units can be 220 nm-850 nm.

[0171] The volume distribution particle size Dv50 of polymer particles containing triazine ring structural units within the above range is beneficial for the separator to have good heat resistance and air permeability.

[0172] This disclosure provides polymer particles containing triazine ring structural units, wherein the swelling degree of these particles after immersion in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%. The embodiments of this disclosure also provide a method for preparing these polymer particles containing triazine ring structural units.

[0173] In some embodiments, a method for preparing polymer particles containing triazine ring structural units includes the following steps: providing a precursor containing a triazine ring structure; heating and curing the precursor containing a triazine ring structure in an oxygen-containing atmosphere, followed by crushing, to obtain polymer particles containing triazine ring structural units; the heating and curing temperature is 180℃-280℃. After heating and curing, a bridging structure is formed between the triazine ring structural units in the precursor containing the triazine ring structure.

[0174] The temperature for heat curing is 180℃-280℃, for example, it can be 180℃, 190℃, 200℃, 210℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, or any combination of the above values.

[0175] Heating and curing temperatures within the above range are beneficial for obtaining polymer particles with good heat resistance and low swelling.

[0176] Optionally, the heat curing temperature can be 200℃-280℃, 210℃-280℃, 220℃-280℃, 230℃-280℃, 200℃-270℃, 210℃-270℃, 220℃-270℃, or 230℃-270℃.

[0177] In some embodiments, the heat curing time can be 2h-8h, for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, or any range of the above values. Optionally, the heat curing time is 3h-8h.

[0178] When the heating and curing time is within the above range, it is beneficial for the precursor containing the triazine ring structure to form polymer particles with smaller swelling.

[0179] In some embodiments, the oxygen-containing atmosphere may include oxygen and an inert gas. Optionally, the inert gas may be one or more of nitrogen, argon, and helium, among others. In some embodiments, the volume fraction of oxygen in the oxygen-containing atmosphere may be 5%-50%. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere may be 10%-30%. More preferably, the oxygen-containing atmosphere may be an air atmosphere.

[0180] In some embodiments, polymer particles containing triazine ring structural units may further include sieving and demagnetization steps after crushing.

[0181] In some embodiments, the precursor containing a triazine ring structure may include at least one of the following: melamine aldehyde resin, etherified melamine aldehyde resin, or a mixture of etherified melamine aldehyde resin and at least one of polyol, polycarboxylic acid, or polyamide.

[0182] In some embodiments, the precursor containing a triazine ring structure may include a melamine aldehyde resin, which may be obtained by reacting an aldehyde compound with an amine-substituted triazine compound, wherein the amine-substituted triazine compound may include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 1.8:1-3:1, for example, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, or any range of the above ratios. More preferably, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 2:1-3:1, 2.1:1-3:1, 2.2:1-3:1, 2.3:1-3:1, or 2.4:1-3:1.

[0183] In some embodiments, the precursor containing a triazine ring structure may include an etherified melamine aldehyde resin, which may be obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound. The amine-substituted triazine compound may include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 5:1-7:1, for example, 5:1, 5.2:1, 5.4:1, 5.6:1, 5.8:1, 6:1, 6.2:1, 6.4:1, 6.6:1, 6.8:1, 7:1, or any range of the above ratios. More preferably, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 5.4:1-7:1, 5.6:1-7:1, 5.8:1-7:1, 6:1-7:1, or 6.2:1-7:1.

[0184] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyol, wherein the molar ratio of the etherified melamine aldehyde resin to the polyol may be 1:2 to 1:6.

[0185] In some embodiments, the precursor containing a triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polycarboxylic acid, wherein the molar ratio of the etherified melamine aldehyde resin to the polycarboxylic acid can be 1:2 to 1:6.

[0186] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyamide, wherein the molar ratio of the etherified melamine aldehyde resin to the polyamide may be 1:2 to 1:6.

[0187] In some embodiments, the alcohol compound that forms the etherified melamine aldehyde resin may include one or more of methanol, ethanol, and butanol.

[0188] In some embodiments, the aldehyde compounds forming melamine aldehyde resins and etherified melamine aldehyde resins may include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0189] In some embodiments, the amine-substituted triazine compound forming melamine-formaldehyde resins and etherified melamine-formaldehyde resins may include one or more compounds of the following general formula: R1 and R2 are independently selected from H, -NH2, and C1-C8 alkyl, R3 is selected from H, -NH2, -NHR4, C1-C8 alkyl, C2-C8 alkenyl, phenyl, C7-C12 alkylphenyl, C7-C12 phenylalkyl, and C5-C8 cycloalkyl, and R4 is selected from -NH2 and C1-C8 alkyl. Optionally, R3 is selected from -NH2 or -NHR4.

[0190] Optionally, the amine-substituted triazine compound may include melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 6-ethyl-1,3,5-triazine-2,4-diamine, 6-isopropyl-1,3,5-triazine-2,4-diamine, 6-pentyl-2,4-diamino-1,3,5-triazine, 6-heptyl-2,4-diamino-triazine, 2-ethyl Alkenyl-4,6-diamino-1,3,5-triazine, 2,4-diamino-6-(4-methylphenyl)-1,3,5-triazine, 6-cyclohexyl-1,3,5-triazine-2,4-diamine, 6-(3-methylphenyl)-1,3,5-triazine-2,4-diamine, 6-o-tolyl-1,3,5-triazine-2,4-diamine, 6-(2,4-dimethylphenyl)-1,3,5-triazine-2,4-diamine, 6-phenylmethyl-1,3,5-triazine-2,4-diamine, (diamino-1,3,5-triazine-2-yl)methanol, and 2-chloro-4,6-diamino-1,3,5-triazine.

[0191] Alternatively, the amine-substituted triazine compound may include one or more of melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, and 2,4-diamino-6-dimethylamino-1,3,5-triazine.

[0192] Etherified melamine-formaldehyde resins may include one or more of partially etherified and fully etherified melamine-formaldehyde resins. Optionally, etherified melamine-formaldehyde resins may include fully etherified melamine-formaldehyde resins.

[0193] In some embodiments, etherified melamine aldehyde resins may include methyl etherified melamine aldehyde resins, diethyl etherified melamine aldehyde resins, butyl etherified melamine aldehyde resins, and methyl-butyl mixed etherified melamine aldehyde resins.

[0194] Optionally, the etherified melamine-formaldehyde resin may include one or more of the following: methyl etherified melamine-formaldehyde resin, butyl etherified melamine-formaldehyde resin, methyl etherified benzyl melamine-formaldehyde resin, and butyl etherified benzyl melamine-formaldehyde resin.

[0195] In some embodiments, the etherified melamine aldehyde resin may be in liquid form.

[0196] [Cross-linked styrene organic particles]

[0197] In some embodiments, crosslinked styrene-based organic particles include styrene or styrene derivative structural units and crosslinked structural units. The crosslinked structural units of crosslinked styrene-based organic particles refer to structural units used to connect the styrene or styrene derivative structural units.

[0198] In some embodiments, the styrene or styrene derivative structural unit may include one or more of the following: styrene structural unit, 1-methyl-1-styrene structural unit, 4-methylstyrene structural unit, 2-methylstyrene structural unit, 2,4-dimethylstyrene structural unit, and 2,5-dimethylstyrene structural unit.

[0199] In some embodiments, the crosslinking structural unit may include one or more of the following: divinylbenzene structural unit, ethylene glycol dimethacrylate structural unit, pentaerythritol tetraacrylate structural unit, 1,4-butanediol diacrylate structural unit, 1,6-hexanediol diacrylate structural unit, 1,8-octanediol diacrylate structural unit, trimethylolpropane triacrylate structural unit, pentaerythritol trimethacrylate structural unit, tetraethylene glycol dimethacrylate structural unit, tripropylene glycol diacrylate structural unit, N,N-methylenebisacrylamide structural unit, N,N'-vinylbisacrylamide structural unit, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit, and triallyl isocyanurate structural unit.

[0200] In some embodiments, the glass transition temperature T of cross-linked styrene organic particles g The temperature range is 114℃-158℃.

[0201] Glass transition temperature T of cross-linked styrene organic particles g It has high heat resistance and good thermal stability, which can better resist the thermal shrinkage of the porous base film, improve the heat resistance of the separator, and improve the reliability of the secondary battery cell.

[0202] In some embodiments, the volume distribution particle size Dv50 of cross-linked styrene organic particles can be 86 nm-300 nm.

[0203] When the volume distribution particle size Dv50 of cross-linked styrene organic particles is within the above range, it is beneficial for the separator to have good heat resistance and air permeability.

[0204] This disclosure provides a cross-linked styrene-based organic particle whose swelling degree after being immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%. The embodiments of this disclosure also provide a method for preparing the cross-linked styrene-based organic particle.

[0205] In some embodiments, the method for preparing crosslinked styrene-based organic particles includes the following steps: providing a pre-emulsion comprising monomers, crosslinking agents, emulsifiers, initiators, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain crosslinked styrene-based organic particles; the monomers include one or more of styrene and its derivatives; the ripening temperature of the emulsion polymerization reaction is 72°C-88°C, and the ripening time of the emulsion polymerization reaction is 1h-5h.

[0206] The maturation temperature of the emulsion polymerization reaction is 72℃-88℃, for example, it can be 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, or any combination of the above values.

[0207] The maturation time for emulsion polymerization is 1-5 hours, for example, it can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, or any range of the above values.

[0208] When the curing temperature and curing time of the emulsion polymerization reaction are within the above range, the heat resistance of cross-linked styrene organic particles can be improved and the swelling degree of cross-linked styrene organic particles can be reduced.

[0209] In some embodiments, the emulsion polymerization reaction may include the following steps: adding a pre-emulsion dropwise into a reactor containing water under a first heating temperature, inert gas protection, and stirring conditions; after a first reaction time, raising the temperature to a ripening temperature for ripening reaction to obtain cross-linked styrene-based organic particles.

[0210] Optionally, the first heating temperature can be 55℃-70℃.

[0211] Optionally, the first time can be 3h-6h.

[0212] In some embodiments, the monomer may include one or more of styrene, 1-methyl-1-styrene, 4-methylstyrene, 2-methylstyrene, 2,4-dimethylstyrene, and 2,5-dimethylstyrene.

[0213] The crosslinking agent polymerizes with the monomer to form crosslinked structural units of crosslinked styrene-based organic particles. In some embodiments, the crosslinking agent may include one or more of the following: divinylbenzene, ethylene glycol dimethacrylate, pentaerythritol tetraacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, N,N-methylenebisacrylamide, N,N'-vinylbisacrylamide, 1,3,5-triacryloylhexahydro-1,3,5-triazine, and triallyl isocyanurate.

[0214] Optionally, the crosslinking agent may include one or more of divinylbenzene, N,N-methylenebisacrylamide, and N,N'-vinylbisacrylamide.

[0215] In some embodiments, the mass fraction of the crosslinking agent can be 8%-35% based on the total mass of the monomer and the crosslinking agent as 100%, for example, it can be 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 35%, or any range of the above values.

[0216] When the mass fraction of the crosslinking agent is within the above range, the heat resistance of the crosslinked styrene organic particles can be further improved and the swelling degree of the crosslinked styrene organic particles can be further reduced.

[0217] Optionally, the mass fraction of the crosslinking agent can be 11%-35%.

[0218] In some embodiments, the emulsifier may include, but is not limited to, one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, fatty acid sorbitan, polysorbate, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol, polyoxyethylene ether emulsifier, cellulose and its derivatives.

[0219] Optionally, the polyoxyethylene ether emulsifier may include OP-type emulsifiers, such as OP-4, OP-7, OP-10, OP-15, OP-20, etc.

[0220] In some embodiments, the mass fraction of the emulsifier may be 0.2%-4% based on the total mass of monomers and crosslinking agents as 100%.

[0221] In some embodiments, the initiator may be one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyramidine hydrochloride, azobisisobutyramidine hydrochloride, and azobisisopropylimidazoline.

[0222] In some embodiments, the method for preparing cross-linked styrene-based organic particles may further include a demagnetization treatment step after the emulsion polymerization reaction is completed.

[0223] [Silicone-containing organic resin granules]

[0224] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, which contain carbon-carbon bonds and silicon-oxygen structures.

[0225] Optionally, the silicon-containing organic resin particles have a network structure with carbon-carbon bonds as the main chain and silicon-oxygen structures in the side chains.

[0226] Optionally, the silicon-containing organic resin particles have a network structure with carbon-carbon bonds as the main chain and side chains containing silicon-oxygen structures and benzene ring structures.

[0227] In some embodiments, the silicon-containing organic crosslinked resin particles include crosslinked structural units. The crosslinked structural units of the silicon-containing organic crosslinked resin particles refer to silicon-free structural units used to connect the silicon-containing structural units.

[0228] Optionally, the crosslinking structural unit may include a divinylbenzene structural unit, a diethylene glycol divinyl ether structural unit, a triethylene glycol divinyl ether structural unit, a diallyl maleate structural unit, an ethylene glycol dimethacrylate structural unit, a 1,4-butanediol diacrylate structural unit, a 1,6-hexanediol diacrylate structural unit, a 1,8-octanediol diacrylate structural unit, a trimethylolpropane triacrylate structural unit, a pentaerythritol trimethacrylate structural unit, a tetraethylene glycol dimethacrylate structural unit, and a diethylene glycol dimethacrylate structural unit. The structural unit comprises one or more of the following: tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0229] The raw materials for silicon-containing organic resin particles may include monomers and multifunctional crosslinking agents. Monomers may include silane coupling agents containing alkenyl and / or acryloyloxy groups. In some embodiments, monomers include vinyl silane coupling agents and / or acryloyloxy silane coupling agents. The multifunctional crosslinking agent polymerizes with the monomer to form the crosslinked structural units of the silicon-containing organic crosslinked resin particles. In some embodiments, the crosslinking agent may include one or more of the following: divinylbenzene, diethylene glycol divinyl ether, triethylene glycol divinyl ether, diallyl maleate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-nonaiyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0230] In some embodiments, the silicone-containing organic resin particles have no glass transition temperature below 300°C.

[0231] Silicon-containing organic resin particles have no glass transition temperature below 300℃, indicating that they have good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0232] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles can be 86nm-300nm.

[0233] The volume distribution particle size Dv50 of the silicone organic resin particles is within the above range, which is beneficial for the separator to have good heat resistance and air permeability.

[0234] This disclosure provides silicon-containing organic resin particles whose swelling degree after being soaked in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%. Embodiments of this disclosure also provide a method for preparing the silicon-containing organic resin particles.

[0235] In some embodiments, the method for preparing silicone-containing organic resin particles includes the following steps: providing a pre-emulsion comprising monomers, multifunctional crosslinking agents, emulsifiers, initiators, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain silicone-containing organic resin particles; the heating temperature during the curing stage of the emulsion polymerization reaction is 80°C-92°C; the heating time during the curing stage of the emulsion polymerization reaction is 2h-5h; and the monomers include silane coupling agents containing alkenyl groups and / or acryloyloxy groups.

[0236] The monomers include silane coupling agents containing alkenyl and / or acryloyloxy groups, thus initiating free radical generation and cross-linking reactions between monomers. Furthermore, the monomers also undergo cross-linking reactions with multifunctional cross-linking agents. Therefore, using the monomers and cross-linking agents disclosed herein as raw materials, three-dimensional network structure silicon-containing organic resin particles can be formed. These particles are not easily softened or deformed at high temperatures, exhibiting high heat resistance and lower swelling degree.

[0237] The heating temperature during the ripening stage of the emulsion polymerization reaction is 80℃-92℃, for example, it can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, or any combination of the above values.

[0238] The heating time for the ripening stage of the emulsion polymerization reaction is 2h-5h, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or any range of the above values.

[0239] When the heating temperature and heating time during the ripening stage of the emulsion polymerization reaction are within the above range, the reaction can be made more complete, thereby improving the heat resistance of the silicone organic resin particles and reducing the swelling degree of the silicone organic resin particles.

[0240] In some embodiments, the emulsion polymerization reaction may include the following steps: adding a pre-emulsion dropwise into a reactor containing water under a second heating temperature, inert gas protection, and stirring conditions; after a second reaction time, raising the temperature to the heating temperature of the maturation stage to carry out a maturation reaction, thereby obtaining silicon-containing organic resin particles.

[0241] Optionally, the second heating temperature can be 55℃-70℃.

[0242] Optionally, the second time can be 3h-6h.

[0243] In some embodiments, the mass fraction of the multifunctional crosslinker can be 4%-14% based on the total mass of the monomer and the multifunctional crosslinker as 100%, for example, it can be 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, or any range of the above values.

[0244] When the mass fraction of the multifunctional crosslinking agent is within the above range, the heat resistance of the silicon-containing organic resin particles can be further improved and the swelling degree of the silicon-containing organic resin particles can be further reduced.

[0245] Multifunctional crosslinking agents polymerize with monomers to form crosslinked structural units of silicon-containing organic crosslinked resin particles. In some embodiments, the multifunctional crosslinking agent may include one or more of the following: divinylbenzene, diethylene glycol divinyl ether, triethylene glycol divinyl ether, diallyl maleate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-nonanoyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0246] In some embodiments, the monomer may include a vinylsilane coupling agent and / or an acryloyloxysilane coupling agent.

[0247] Optionally, the monomer may include γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-tert-butoxyvinylsilane, vinyltri... One or more of the following: (β-methoxyethoxy)silane, ethylenetri[(1-methylvinyl)oxy]silane, vinyltritert-butylperoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane.

[0248] In some embodiments, a monomer may include a first monomer and a second monomer.

[0249] The first monomer may include one or more of the following: γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tritert-butoxyvinylsilane, vinyltris(β-methoxyethoxy)silane, ethylenetris[(1-methylvinyl)oxy]silane, and vinyltritert-butylperoxysilane.

[0250] The second monomer may include one or more of the following: 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane.

[0251] The first and second monomers have different activities. By combining them and reacting them with a crosslinking agent, silicone organic resin particles with a narrow particle size distribution can be obtained.

[0252] In some embodiments, the emulsifier may be one or more of alkyl sulfates, alkyl sulfonates, Tween emulsifiers, fatty alcohol polyoxyethylene ethers, fatty alcohol polyoxypropylene ethers, cetearyl alcohol polyethers, and oleyl alcohol polyethers.

[0253] Optionally, the emulsifier may include one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, Tween 20, Tween 40, lauryl ether-7, lauryl ether-9, lauryl ether-10, and oleyl ether-10.

[0254] In some embodiments, the initiator may be one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyronitrile, azobisisobutyramidine hydrochloride, azobisisobutyramidine imidazoline hydrochloride, and azobisisopropylimidazoline.

[0255] In some embodiments, the preemulsion may further include a pH adjuster. Optionally, the pH adjuster may include, but is not limited to, one or more of sodium bicarbonate, sodium hydroxide, ammonia, etc.

[0256] In some embodiments, the method for preparing silicone organic resin particles may further include a demagnetization treatment step after the emulsion polymerization reaction is completed.

[0257] Glass transition temperature T gThe test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The glass transition temperature Tg of the organic particles can be obtained through the DSC curve, or it can be used to determine whether the organic particles have a glass transition temperature Tg. g .

[0258] Glass transition temperature T g It refers to the transition temperature from the glassy state to the elastic state, which shows a step-like change on the DSC curve.

[0259] Organic particles have no glass transition temperature T below 300℃ g This means that the DSC curve of organic particles does not show a step-like change in the range below 300℃.

[0260] Dv50 represents the particle size corresponding to a cumulative volumetric distribution percentage of 50% for the material. It can be measured using a laser particle size analyzer, referring to GB / T 19077-2016. During testing, add 1g of the sample to a clean small beaker, along with 20ml of deionized water. Sonicate at 53kHz / 120W for 5 minutes to ensure complete dispersion. Turn on the laser particle size analyzer, clean the optical path system, and automatically test the background. Stir the sonicated solution to ensure uniform dispersion, then place it in the sample cell as required and begin measuring the particle size. A MasterSizer 3000 laser particle size analyzer can be used as the testing instrument.

[0261] In some embodiments, the organic particle content in the coating may be 50%-99% based on the total mass of the coating.

[0262] Optionally, the mass content of organic particles in the coating can be 60%-99%, 70%-99%, 80%-99%, 85%-99%, 88%-99%, 80%-97%, 85%-97%, 88%-97%, 80%-95%, 85%-95%, or 88%-95%.

[0263] In some embodiments, the binder in the coating may include, but is not limited to, one or more of the following: polyacrylate binders, nitrile rubber binders, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0264] In some embodiments, the coating may also include a dispersant, such as, but not limited to, polyacrylic acid dispersants or carboxymethyl cellulose dispersants. As an example, the dispersant may include, but is not limited to, one or more of sodium carboxymethyl cellulose, sodium polyacrylate, and ammonium polyacrylate.

[0265] In some embodiments, the separator may further include polymer binder particles. These polymer binder particles serve to improve the adhesion between the separator and the electrode, and they are essentially not heat-resistant.

[0266] In some embodiments, polymer binder particles may be embedded in organic particles and form protrusions on the coating surface.

[0267] In other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on the porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the heat-resistant layer on the side away from the porous base membrane. Organic particles are disposed in the heat-resistant layer, and polymer binder particles are disposed in the adhesive layer.

[0268] In some other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer, the heat-resistant layer being disposed on one side of the porous base membrane, the adhesive layer being disposed on at least a portion of the surface of the other side of the porous base membrane, organic particles being disposed in the heat-resistant layer, and polymer binder particles being disposed in the adhesive layer.

[0269] In some embodiments, the average particle size of the polymer binder particles can be 6 μm-18 μm.

[0270] The average particle size of the test particles can be tested as follows: Using a scanning electron microscope (SEM) according to JY / T 010-1996, obtain an SEM image of the separator. Randomly select a test sample with dimensions of 50mm x 100mm on the separator. Randomly select multiple test areas (e.g., 5) within the test sample, and read the particle size of the test particles in each test area at a certain magnification (e.g., 500x or higher). Count the number and particle size values ​​of the test particles in each test area, and take the arithmetic mean of the particle sizes in all test areas as the average particle size. To ensure the accuracy of the test results, multiple test samples (e.g., 10) can be used for the above test, and the average value of each test sample can be taken as the final test result. The testing instrument can be a ZEISS Sigma 300. It should be noted that when the test particles are irregularly shaped, the distance between the two farthest points on the test particle should be taken as the particle size.

[0271] In some embodiments, the polymer binder particles may include vinylidene fluoride polymer particles, such as polyvinylidene fluoride (PVDF) particles and / or copolymer particles of vinylidene fluoride monomer and comonomer.

[0272] Comonomers may include at least one of olefin monomers, fluorinated olefin monomers, chlorinated olefin monomers, acrylate monomers, acrylic monomers, and fluoroether monomers.

[0273] Optionally, the comonomer may include at least one of the following: trifluoroethylene, trifluorochloroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl) ether (e.g., perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether), perfluoro(1,3-m-dioxacyclopentene), and perfluoro(2,2-dimethyl-1,3-m-dioxacyclopentene).

[0274] In some embodiments, the coating thickness can be 0.5 μm-5 μm. The coating thickness refers to the thickness of the coating on one side of the porous base membrane. Optionally, the coating thickness can be 0.5 μm-4 μm, 0.5 μm-3 μm, 0.5 μm-2 μm, 0.6 μm-4 μm, 0.6 μm-3 μm, 0.6 μm-2 μm, 0.8 μm-4 μm, 0.8 μm-3 μm, or 0.8 μm-2 μm.

[0275] In some embodiments, the areal density of the coating may be 0.45 g / m². 2 -5g / m 2 .

[0276] In some embodiments, the porous base membrane may comprise a membrane or nonwoven web selected from any one or at least two of the following: polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymer, polyphenylene sulfide, and polyvinylnaphthalene.

[0277] Porous base membranes can be single-layer thin films or multi-layer composite thin films. When a porous base membrane is a multi-layer composite thin film, the materials of each layer can be the same or different.

[0278] In some embodiments, the thickness of the porous base film can be 4μm-12μm, and optionally 4μm-9μm.

[0279] In some embodiments, the porosity of the porous base membrane can be 25%-60%, optionally 28%-50%.

[0280] In some embodiments, the ratio of the volume distribution particle size Dv50 of the organic particles to the average pore size of the porous base membrane can be greater than or equal to 1.1.

[0281] The volume distribution particle size Dv50 of the organic particles has the same unit, e.g., nm, as the average pore size of the porous membrane.

[0282] This can reduce pore blockage and improve the air permeability and ion conduction properties of the separator.

[0283] In some embodiments, the average pore size of the porous base film can be 25 nm to 82 nm.

[0284] The average pore size of the porous membrane can be measured using a capillary porosity analyzer (bubble point method). An exemplary testing method is as follows: Take a circular sample with a diameter of 25 mm, and drop 3-5 drops of wetting solution onto it. After the sample is completely wetted, place it in a mold. Then, use an inert gas (such as nitrogen) to compress the wetting solution in the pores of the sample. The compression pressure and flow rate are inversely proportional to the pore size. The average pore size of the sample is obtained through software sampling and pressure-pore size conversion analysis. The testing instrument can be a PMI CFP 1500 pore size analyzer, with a testing pressure ranging from 100 psi to 350 psi.

[0285] In some embodiments, the thickness of the separator can be 5μm-14μm, optionally 5μm-12μm or 6μm-12μm. This is beneficial for improving the energy density of the secondary battery cell.

[0286] In some embodiments, the air permeability of the separator can be 160s / 100ml-230s / 100ml, and optionally 170s / 100ml-220s / 100ml.

[0287] It should be noted that the coating parameters of the above-mentioned separators are coating parameters for one side of the porous base membrane. When the coating is applied to both sides of the porous base membrane, if the coating parameters of either side meet the requirements of this disclosure, it is considered to fall within the protection scope of this disclosure.

[0288] The separator membrane can be prepared according to methods known in the art.

[0289] In some embodiments, a slurry including organic particles and a binder can be coated on at least one side of a porous base membrane, and after drying, a separation membrane is obtained.

[0290] In some embodiments, the slurry may further include polymer binder particles, which, after drying, are embedded in organic particles and form protrusions on the coating surface.

[0291] In some embodiments, the method for preparing the separator membrane may include: applying a heat-resistant layer slurry comprising organic particles and a binder to at least one side of a porous base membrane, and drying it to form a heat-resistant layer; and applying an adhesive layer slurry comprising polymer binder particles and a binder to at least a portion of the surface of the heat-resistant layer, and drying it to obtain the separator membrane.

[0292] In some embodiments, the method for preparing the separator membrane may include: coating a heat-resistant slurry comprising organic particles and a binder onto one side of a porous base membrane, and coating an adhesive layer slurry comprising polymer binder particles and a binder onto at least a portion of the surface of the other side of the porous base membrane, and drying the slurry to obtain the separator membrane.

[0293] In some embodiments, the solvent for the slurry may be water, such as deionized water.

[0294] In some embodiments, the slurry may also include other components, such as dispersants and / or wetting agents.

[0295] This disclosure also provides a secondary battery cell. The secondary battery cell includes the separator provided in this disclosure.

[0296] A secondary battery cell also includes a positive electrode, a negative electrode, and an electrolyte, with a separator disposed between the positive and negative electrodes. The positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process.

[0297] The secondary battery cells disclosed herein may include, but are not limited to, lithium battery cells, sodium battery cells, etc. The composition of the positive electrode, negative electrode and electrolyte may differ depending on the type of secondary battery cell.

[0298] [Positive electrode plate]

[0299] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector and comprising a positive electrode active material. For example, the positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0300] Taking a lithium-ion battery cell as an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, 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 their respective modified compounds. In some embodiments, to further improve the energy density of the secondary battery cell, the positive electrode active material may include materials with the general formula Li a Ni b Co c M d O e A f One or more of lithium transition metal oxides and their modified compounds. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes but is not limited to one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes but is not limited to one or more of N, F, S and Cl.

[0301] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.1 Al 0.05 One or more of O2, LiFePO4, and LiMnPO4.

[0302] During the charging and discharging process, Li undergoes insertion / extraction and consumption in a single secondary battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to a secondary battery cell, the molar Li content changes after charge-discharge cycles. Similarly, in the examples of positive electrode active materials in this disclosure, the molar O content is only a theoretical value. Lattice oxygen release causes changes in the molar O content, and the actual molar O content will also fluctuate.

[0303] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-x In this case, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes, but is not limited to, H. + Li + Na + K + and NH4 + One or more of the following, M' is a transition metal cation, optionally including but not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally one or more of F, Cl and Br.

[0304] The modified compounds for the positive electrode active materials of the aforementioned lithium battery cells and sodium battery cells can be obtained by doping and / or surface coating modifications of the positive electrode active materials.

[0305] In some embodiments, the positive electrode film layer may further include a positive electrode conductive agent. As an example, the positive electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0306] In some embodiments, the positive electrode film layer may further include a positive electrode binder. As an example, the positive electrode binder may include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0307] In some embodiments, the positive current collector may be a metal foil or a composite current collector. An example of a metal foil is aluminum foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0308] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing positive electrode active materials, positive electrode conductive agents, positive electrode binders, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0309] [Negative electrode plate]

[0310] In some embodiments, the negative electrode sheet may include a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector and comprising a negative electrode active material. For example, the negative current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0311] The negative electrode active material may be any material known in the art for use in secondary battery cells. As an example, the negative electrode active material may include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may include, but are not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include, but are not limited to, one or more of elemental tin, tin oxide, and tin alloys.

[0312] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0313] In some embodiments, the negative electrode film layer may further include a negative electrode binder. As an example, the negative electrode binder may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0314] In some embodiments, the negative electrode film layer may also include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, etc.

[0315] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. As an example of a metal foil, copper foil may be used. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0316] The negative electrode film is typically formed by coating a negative electrode slurry onto a negative electrode current collector, followed by drying and cold pressing. The negative electrode slurry is usually formed by dispersing the negative electrode active material, negative electrode conductive agent, negative electrode binder, and other optional additives in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP) or deionized water, but is not limited to these.

[0317] The negative electrode sheet does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode sheet also includes a conductive undercoat layer (e.g., composed of a conductive agent and a binder) sandwiched between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector.

[0318] In some embodiments, the negative electrode sheet can be made of foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not contain a negative electrode active material.

[0319] [Electrolytes]

[0320] The electrolyte plays a role in conducting ions between the positive and negative electrode plates.

[0321] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0322] Taking a lithium battery cell as an example, the electrolyte salt may include, but is not limited to, one or more of the following: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0323] Taking sodium battery cells as an example, the electrolyte salt may include, but is not limited to, one or more of the following: sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium difluorosulfonyl imide (NaFSI), sodium difluoromethanesulfonyl imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium dioxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0324] In some embodiments, the organic solvent may include, but is not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), 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), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0325] In some embodiments, the electrolyte may also include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the secondary battery cell, such as additives that improve overcharge performance, additives that improve high-temperature performance, additives that improve low-temperature performance, etc.

[0326] Optionally, the additive may include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), and ethylene sulfate (DTD).

[0327] Methods for preparing secondary battery cells are well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form a secondary battery cell. As an example, the positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process. The electrode assembly is placed in an outer packaging, dried, and then injected with the aforementioned electrolyte. After vacuum sealing, settling, and formation processes, a secondary battery cell is obtained.

[0328] Example

[0329] The following embodiments describe the disclosure of this disclosure in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0330] A commercially available phenolic resin material, consisting of phenol and formaldehyde, was placed in a curing oven. The atmosphere was set to air, and the temperature was set to 155°C. This temperature was maintained for 2 hours. After curing, the oven temperature was increased to 270°C and maintained for 3 hours. After both curing cycles, the cured phenolic resin material was removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles 1-1#.

[0331] A commercially available phenolic resin material, consisting of phenol and formaldehyde, was placed in a curing oven. The atmosphere was set to air, and the temperature was set to 155°C. This temperature was maintained for 2 hours. After curing, the oven temperature was increased to 290°C and maintained for 3 hours. After both curing cycles, the cured phenolic resin material was removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles #1-2.

[0332] Commercially available phenolic resin materials, consisting of phenol and formaldehyde, were placed in a curing oven. The atmosphere was set to air, and the temperature was set to 155°C. Curing was carried out at this temperature for 2 hours. After curing, the temperature of the curing oven was increased to 250°C and maintained for 3 hours. After both curing processes, the cured phenolic resin materials were removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles 1-3#.

[0333] Commercially available phenolic resin materials, consisting of phenol and formaldehyde, were placed in a curing oven. The atmosphere was set to air, and the temperature was set to 170℃, maintaining this temperature for 2 hours. After curing, the oven temperature was increased to 270℃ and maintained for 3 hours. After both curing cycles, the cured phenolic resin materials were removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles 1-4#.

[0334] A commercially available phenolic resin material, consisting of phenol and formaldehyde, was placed in a curing oven. The atmosphere was set to air, and the temperature was set to 350℃. The curing was maintained at this temperature for 4 hours. After curing, the cured phenolic resin material was removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles D1-1#.

[0335] Organic Particle Performance Testing

[0336] (1) Glass transition temperature T of organic particles g test

[0337] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. Obtain the glass transition temperature T of the organic particles using the DSC curve. g Or determine whether organic particles have a glass transition temperature T. g .

[0338] (2) Melting point test of organic particles

[0339] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. Determine whether the organic particles have a melting point using the DSC curve.

[0340] (3) Swelling degree test of organic particles

[0341] Take an appropriate amount of sample (e.g., about 1g), and record its mass as m1. Place it in a semi-permeable membrane sample bag and seal it. The sample bag should be permeable to the solvent but not to the sample. Immerse the sample bag in an appropriate amount of solvent (e.g., about 50g) at 60°C for 7 days. After that, remove the sample bag and then remove the sample from the sample bag. Wipe off any excess solvent and weigh the sample again, m2. The swelling degree = (m2-m1) / m1 × 100%. The solvent is a mixed solvent obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7.

[0342] The organic particles 1-1# to 1-4# prepared above meet the following characteristics: the phenolic resin organic particles are thermosetting propylene resin polymers, which have no melting point and no glass transition temperature T below 300℃. g .

[0343] Next, the organic particles prepared above were used in the separator to verify their impact on the performance of the separator and the secondary battery cells.

[0344] The preparation process of the separator membrane is as follows.

[0345] A commercially available 7 μm thick polyethylene microporous membrane was used as the porous base membrane. The prepared organic particles, dispersant sodium carboxymethyl cellulose, and binder polyacrylate were mixed evenly in deionized water at a solid mass ratio of 90:2:8 to obtain a slurry. The slurry was uniformly coated onto both surfaces of the porous base membrane, and dried to remove the solvent, resulting in a separating membrane. The coating thickness was 1.5 μm, and the separating membrane thickness was 10 μm.

[0346] The manufacturing process of a secondary battery cell is as follows.

[0347] The positive electrode active material LiFePO4, the positive electrode binder polyvinylidene fluoride (PVDF), and the positive electrode conductive agent carbon black were added to N-methylpyrrolidone (NMP) at a mass ratio of 97:2:1 and thoroughly mixed to prepare a positive electrode slurry. The positive electrode slurry was then uniformly coated onto the positive electrode current collector aluminum foil, and then dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0348] Artificial graphite (anode active material), acetylene black (anode conductive agent), styrene-butadiene rubber (SBR) (anode binder), and sodium carboxymethyl cellulose (thickener) were added to deionized water at a mass ratio of 96.0:1.5:1.5:1. After thorough mixing, a cathode slurry was prepared. The cathode slurry was then uniformly coated onto copper foil (anode current collector), and subsequently dried, cold-pressed, and slit to obtain the cathode sheet.

[0349] At 25°C, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7 to obtain a mixed solvent. LiPF6 and vinylene carbonate (VC) were then dissolved in this mixed solvent to obtain the electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of VC was 3%, based on the mass of the electrolyte.

[0350] The positive electrode sheet, separator, and negative electrode sheet are stacked, wound, and hot-pressed in sequence to obtain an electrode assembly. The electrode assembly is then placed in an aluminum-plastic film for top and side sealing. After processes such as electrolyte injection, standing, formation, aging, venting, and secondary sealing, a soft-pack secondary battery cell is obtained.

[0351] Performance testing

[0352] (1) Thermal shrinkage rate test of the separator film

[0353] The heat shrinkage rate test of the release liner can be referenced in GB / T 36363-2018.

[0354] Cut the release film into samples with a width of 50mm and a length of 100mm using a punching machine. Take 5 parallel samples and place them on A4 paper. Then place the A4 paper containing the samples on corrugated paper with a thickness of 1mm to 5mm.

[0355] Set the temperature of the forced-air drying oven to 130℃. After the temperature reaches the set temperature and stabilizes for 60 minutes, place the A4 paper placed on the corrugated paper into the forced-air drying oven and start timing. After the set time (1 hour in this disclosure) is reached, measure the length and width of the isolation film, and mark the values ​​as a and b respectively.

[0356] Calculation of heat shrinkage rate: Longitudinal (MD) heat shrinkage rate = [(100-a) / 100]×100%, Transverse (TD) heat shrinkage rate = [(50-b) / 50]×100%, take the average value of 3 parallel samples as the test result.

[0357] (2) Air permeability test of the separator membrane

[0358] For the air permeability test of the separator membrane, please refer to GB / T 36363-2018.

[0359] Cut the separator membrane into 5cm squares. Using a breathability meter, apply a pressure of 1.21kPa and test the permeability of 100ml of air, finding it to be 6.45cm. 2 The time required for the isolation membrane to form a gas permeability value, expressed in seconds per 100 ml. The average of three parallel samples is taken as the test result. A higher gas permeability value indicates poorer air permeability.

[0360] (3) DC resistance (DCR) test of secondary battery cells

[0361] At 25℃, a single secondary battery cell was charged to 3.8V using a constant current rate of 0.33C, then charged to 0.05C using a constant voltage rate. After resting for 5 minutes, it was discharged to 2V using a constant current rate of 0.33C. The constant current discharge capacity was recorded and denoted as the initial capacity C0. The cell was then rested for 5 minutes, charged to 3.8V using a constant current rate of 0.33C0, then charged to 0.05C using a constant voltage rate. After resting for 5 minutes, it was discharged to 1.5h using a constant current rate of 0.33C0, rested for 30 minutes, and then discharged to 30s using a constant current rate of 3C0, rested for 5 minutes. The voltage values ​​before and after the 1.5C0 constant current discharge were recorded as U1 and U2, respectively. The DCR of the secondary battery cell at 50% SOC was calculated using the formula DCR=(U1-U2) / 1.5C0.

[0362] Table 1

[0363] As can be seen from the above test results, the phenolic resin organic particles prepared in this embodiment have a low degree of swelling, which can make the separator have high heat resistance and high air permeability, and make the secondary battery cell have low internal resistance and good kinetic performance.

[0364] Next, the phenolic resin organic particles will be replaced with polymer particles containing triazine ring structural units.

[0365] Commercially available melamine-formaldehyde resin granules were cured in air at 230°C for 4.5 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules 2-1# containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.4:1.

[0366] Commercially available melamine-formaldehyde resin granules were cured in air at 245°C for 4.5 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules 2-2# containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.4:1.

[0367] Commercially available melamine-formaldehyde resin granules were cured in air at 260°C for 4.5 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules (2-3#) containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.4:1.

[0368] Commercially available melamine-formaldehyde resin granules were cured in air at 150°C for 4.5 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules D2-1# containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.4:1.

[0369] The organic particles 2-1# to 2-3# prepared above also meet the following characteristics: no melting point, and no glass transition temperature T below 300℃. g .

[0370] Table 2

[0371] As can be seen from the above test results, the polymer particles containing triazine ring structural units prepared in this embodiment have a low degree of swelling, which can make the separator have high heat resistance and high air permeability, and make the secondary battery cell have low internal resistance and good kinetic performance.

[0372] Next, the phenolic resin organic particles will be replaced with cross-linked styrene organic particles.

[0373] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 29 g styrene, and 11 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water was added to a reactor, and the temperature was raised to 68 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 75 °C and the reaction was allowed to mature for 2 hours to obtain a cross-linked styrene-based organic particle emulsion 3-1#.

[0374] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 26 g styrene, and 14 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water was added to a reactor, and the temperature was raised to 68 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 75 °C and the reaction was allowed to mature for 2 hours to obtain a cross-linked styrene-based organic particle emulsion 3-2#.

[0375] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 31.5 g styrene, and 8.5 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water was added to a reactor, and the temperature was raised to 68 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 75 °C and the reaction was allowed to mature for 2 hours to obtain a cross-linked styrene-based organic particle emulsion 3-3#.

[0376] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 39.5 g styrene, and 0.5 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water was added to a reactor, and the temperature was raised to 68 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 75 °C and the reaction was allowed to mature for 2 hours to obtain a cross-linked styrene-based organic particle emulsion, D3-1#.

[0377] The organic particles 3-1# to 3-3# prepared above meet the following characteristics: no melting point, glass transition temperature T g Between 114℃ and 158℃.

[0378] Table 3

[0379] As can be seen from the above test results, the cross-linked styrene-based organic particles prepared in this embodiment have a low degree of swelling, which can give the separator high heat resistance and high air permeability, and give the secondary battery cell low internal resistance and good kinetic performance.

[0380] Next, the phenolic resin organic particles will be replaced with silicon-containing organic resin particles.

[0381] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52.2g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-(methacryloyloxy)propylmethyldiethoxysilane, and 4.8g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 90°C and the reaction was allowed to mature for 2 hours to obtain the 4-1# emulsion containing silicon-containing organic resin particles.

[0382] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 49.8g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-(methacryloyloxy)propylmethyldiethoxysilane, and 7.2g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 90°C and the reaction was allowed to mature for 2 hours to obtain the 4-2# emulsion containing silicon-containing organic resin particles.

[0383] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52.2g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-(methacryloyloxy)propylmethyldiethoxysilane, and 4.8g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 80°C and the reaction was allowed to mature for 3 hours to obtain the 4-3# emulsion containing silicon-containing organic resin particles.

[0384] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 57g γ-methacryloyloxypropyltriisopropoxysilane, and 3g 3-(methacryloyloxy)propylmethyldiethoxysilane. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 75°C and the reaction was allowed to mature for 1 hour to obtain the silicon-containing organic resin particle D4-1# emulsion.

[0385] The organic particles 4-1# to 4-3# prepared above meet the following characteristics: the silicon-containing organic resin particles have a network structure formed by carbon-carbon bonds as the main chain, the side chains contain silicon-oxygen structures, they have no melting point, and they have no glass transition temperature T below 300℃. g .

[0386] Table 4

[0387] As can be seen from the above test results, the silicon-containing organic resin particles prepared in this embodiment have a low degree of swelling, which can make the separator have high heat resistance and high air permeability, and make the secondary battery cell have low internal resistance and good kinetic performance.

[0388] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same essential structure and achieving the same effect as the technical concept within the scope of this disclosure are included in the technical scope of this disclosure. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, are also included in the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A secondary battery cell comprising a positive electrode sheet, a negative electrode sheet, and a separator film provided between the positive electrode sheet and the negative electrode sheet, the separator film comprising a porous base film and a coating layer on at least one side of the porous base film, wherein, The coating layer comprises organic particles, and the swelling degree of the organic particles in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

2. The secondary battery cell according to claim 1, wherein The swelling degree of the organic particles in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 2.5%. 3.The secondary battery cell of any one of claims 1-2, wherein, The true density of the organic particles is 1.0 g / cm 3 -2.0 g / cm 3 ; optionally 1.0 g / cm 3 -1.8 g / cm 3 ; and / or, The volume distribution particle size Dv50 of the organic particles is less than 1 μm, and is optionally 50 nm-850 nm. 4.The secondary battery cell of any one of claims 1-3, wherein, The organic particles are at least one of thermosetting resin polymers or crosslinked polymers; and / or, The organic particles are amorphous polymers.

5. The secondary battery cell according to any one of claims 1 to 4, wherein The organic particles have no melting point.

6. The secondary battery cell according to any one of claims 1 to 5, wherein The organic particles comprise one or more of phenolic resin-based organic particles, polymer particles containing triazine ring structure units, crosslinked styrene-based organic particles, and silicon-containing organic resin particles. 7.The secondary battery cell of claim 6, wherein, The phenolic resin-based organic particles are thermosetting resol polymers; and / or, The phenolic resin-based organic particles have no glass transition temperature below 300°C; and / or, The volume distribution particle size Dv50 of the phenolic resin-based organic particles is 220 nm-850 nm. 8.The secondary battery cell of any one of claims 6-7, wherein, The polymer particles containing triazine ring structure units comprise a bridging structure connecting the triazine ring structure units; and / or, The polymer particles containing triazine ring structure units have no glass transition temperature below 300°C; and / or, The volume distribution particle size Dv50 of the polymer particles containing triazine ring structure units is 220 nm-850 nm.

9. The secondary battery cell according to claim 8, wherein The bridging structure comprises one or a combination of two or more of alkylene, alkylene ether, alkylene amine, ester group, and amide group.

10. The secondary battery cell according to any one of claims 6-9, wherein, The polymer particles containing triazine ring structure units further comprise a substituent on the triazine ring structure units, and the substituent comprises one or a combination of two or more of alkyl, alkenyl, phenyl, cycloalkyl, amine group, hydroxyl, and halogen.

11. The secondary battery cell according to any one of claims 6-10, wherein, The polymer particles containing triazine ring structure units comprise at least one of melamine formaldehyde-based polymers and derivatives thereof, etherified melamine formaldehyde-based polymers and derivatives thereof, etherified melamine formaldehyde-polyol polymers and derivatives thereof, etherified melamine formaldehyde-polycarboxylic acid polymers and derivatives thereof, and etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof. 12.The secondary battery cell of claim 11, wherein, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine formaldehyde-oxamide polymer, a methyletherified melamine formaldehyde-malonamide polymer, a methyletherified melamine formaldehyde-iso-phthalimide polymer, a buthyletherified melamine formaldehyde-oxamide polymer, a buthyletherified melamine formaldehyde-malonamide polymer, a buthyletherified melamine formaldehyde-iso-phthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine formaldehyde-oxamide polymer, a methyletherified melamine formaldehyde-malonamide polymer, a methyletherified melamine formaldehyde-iso-phthalimide polymer, a buthyletherified melamine formaldehyde-oxamide polymer, a buthyletherified melamine formaldehyde-malonamide polymer, a buthyletherified melamine formaldehyde-iso-phthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine formaldehyde-oxamide polymer, a methyletherified melamine formaldehyde-malonamide polymer, a methyletherified melamine formaldehyde-iso-phthalimide polymer, a buthyletherified melamine formaldehyde-oxamide polymer, a buthyletherified melamine formaldehyde-malonamide polymer, a buthyletherified melamine formaldehyde-iso-phthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine formaldehyde-oxamide polymer, a methyletherified melamine formaldehyde-malonamide polymer, a methyletherified melamine formaldehyde-iso-phthalimide polymer, a buthyletherified melamine formaldehyde-oxamide polymer, a buthyletherified melamine formaldehyde-malonamide polymer, a buthyletherified melamine formaldehyde-iso-phthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine formaldehyde-oxamide polymer, a methyletherified melamine formaldehyde-malonamide polymer, a methyletherified melamine formaldehyde-iso-phthalimide polymer, a buthyletherified melamine formaldehyde-oxamide polymer, a buthyletherified melamine formaldehyde-malonamide polymer, a buthyletherified melamine formaldehyde-iso-phthalimide polymer; and / or, 13. The secondary battery cell of any one of claims 6-12, wherein, the crosslinked styrene-based organic particles include styrene or styrene derivative structural units and crosslinking structural units; and / or, The crosslinked styrenic organic particles have a glass transition temperature Tg g of 114 °C to 158 °C; and / or, the crosslinked styrene-based organic particles have a volume distribution particle size Dv50 of 86 nm to 300 nm.

14. The secondary battery cell of claim 13, wherein, The styrene or styrene derivative structural unit includes one or more of a styrene structural unit, a 1-methyl-1-styrene structural unit, a 4-methylstyrene structural unit, a 2-methylstyrene structural unit, a 2,4-dimethylstyrene structural unit, a 2,5-dimethylstyrene structural unit; and / or, The crosslinking structural unit includes one or more of a divinylbenzene structural unit, a ethylene glycol dimethacrylate structural unit, a pentaerythritol tetraacrylate structural unit, a 1,4-butanediol diacrylate structural unit, a 1,6-hexanediol diacrylate structural unit, a 1,8-octanediol diacrylate structural unit, a trimethylolpropane triacrylate structural unit, a pentaerythritol trimethacrylate structural unit, a tetraethylene glycol dimethacrylate structural unit, a tripropylene glycol diacrylate structural unit, a N,N-methylenebisacrylamide structural unit, a N,N'-vinylbisacrylamide structural unit, a 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit, a trisallyl isocyanurate structural unit.

15. The secondary battery cell according to any one of claims 6 to 14, wherein The silicon-containing organic resin particles are silicon-containing organic crosslinking resin particles, and the silicon-containing organic resin particles contain a carbon-carbon bond and a siloxane structure; and / or, The silicon-containing organic resin particles have no glass transition temperature at 300°C or lower; and / or, The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 86 nm to 300 nm.

16. The secondary battery cell of any one of claims 6-15, wherein, The silicon-containing organic resin particles are silicon-containing organic crosslinking resin particles, and the silicon-containing organic resin particles are network structures formed with a carbon-carbon bond as a main chain, and a side chain containing a siloxane structure.

17. The secondary battery cell of any one of claims 15-16, wherein, The silicon-containing organic crosslinking resin particles include a crosslinking structural unit; Optionally, the crosslinking structural unit includes one or more of a divinylbenzene structural unit, a diethylene glycol divinyl ether structural unit, a triethylene glycol divinyl ether structural unit, a maleic acid diallyl ester structural unit, an ethylene glycol dimethacrylate structural unit, a 1,4-butanediol diacrylate structural unit, a 1,6-hexanediol diacrylate structural unit, a 1,8-octanediol diacrylate structural unit, a trimethylolpropane triacrylate structural unit, a pentaerythritol trimethacrylate structural unit, a tetraethylene glycol dimethacrylate structural unit, a tripropylene glycol diacrylate structural unit, a 2,2,4-trimethyladipoyl di[2-ethylaziridine] structural unit, a 1,1-sebacoyl di[2-methylaziridine] structural unit, a 1,1-(1,3-phenylenedicarbonyl) di[2-methylaziridine] structural unit, a trimethylolpropane tri(2-methyl-1-aziridinyl propionate) structural unit, a trimethylolpropane-tris[3-(2-methylaziridinyl) propionate] structural unit, a pentaerythritol tri(3-aziridinyl) propionate structural unit.

18. The secondary battery cell of any one of claims 1-17, wherein, The ratio of the volume distribution particle size Dv50 of the organic particles to the average pore diameter of the porous base film is greater than or equal to 1.

1.

19. The secondary battery cell according to any one of claims 1 to 18, wherein The coating further comprises a binder; and / or, The mass content of the organic particles is 50%-99% based on the total mass of the coating; and / or, The thickness of the coating is 0.5 μm-5 μm; and / or, The areal density of the coating is 0.45 g / m 2 - 5 g / m 2 .

20. The secondary battery cell of any one of claims 1-19, wherein, The air permeability of the separator film is 160 s / 100 ml-230 s / 100 ml.

21. A battery device comprising a plurality of secondary battery cells according to any one of claims 1-20.

22. An electric device comprising a secondary battery cell according to any one of claims 1-20 or a battery device according to claim 21.

23. A separator membrane comprising a porous base membrane and a coating on at least one side of the porous base membrane, wherein, The coating comprises organic particles, and the swelling degree of the organic particles after immersion in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

24. The separator film according to claim 23, wherein, The true density of the organic particles is 1.0 g / cm 3 -2.0 g / cm 3 ; optionally 1.0 g / cm 3 -1.8 g / cm 3 ; and / or, The volume distribution particle size Dv50 of the organic particles is less than 1 μm, and is optionally 50 nm-850 nm.

25. The separator film according to any one of claims 23-24, wherein, The organic particles are at least one of thermosetting resin polymers or crosslinked polymers; and / or, The organic particles are amorphous polymers.

26. The separator membrane according to any one of claims 23-25, wherein, The organic particles have no melting point.

27. The separator membrane of any one of claims 23-26, wherein, The organic particles comprise one or more of phenol formaldehyde resin organic particles, polymer particles containing triazine ring structure units, crosslinked styrene organic particles, and silicon-containing organic resin particles. The organic particles have no melting point. The organic particles comprise one or more of phenol formaldehyde resin organic particles, polymer particles containing triazine ring structure units, crosslinked styrene organic particles, and silicon-containing organic resin particles.

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