Separator, preparation method therefor, secondary battery cell, battery device and electrical device

Abstract

Provided are a separator and a preparation method therefor, a secondary battery cell, a battery device and an electrical device. The separator comprises a porous base film and a porous coating located on at least one side of the porous base film, the porous coating comprising organic particles, and the organic particles comprising first organic particles and second organic particles. Both the first organic particles and the second organic particles have a glass transition temperature Tg, the glass transition temperature Tg of the first organic particles being different from the glass transition temperature Tg of the second organic particles; or the first organic particles have a glass transition temperature Tg, and, below 300°C, the second organic particles have no glass transition temperature Tg. The separator is used in the secondary battery cell, such that the secondary battery cell has both high energy density and high reliability.

Description

Separator and method for manufacturing the same, secondary battery cell, battery device, and power using device

[0001] Cross Reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202411388300.1, filed on September 30, 2024, entitled “Separator and method for manufacturing the same, secondary battery cell, battery device, and power using device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to a separator and method for manufacturing the same, secondary battery cell, battery device, and power using 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 and reliability of secondary battery cells. Therefore, how to make the secondary battery cell have higher energy density under the premise of high reliability is a technical problem to be solved at present. SUMMARY

[0005] The present disclosure provides a separator and method for manufacturing the same, secondary battery cell, battery device, and power using device, which is used in a secondary battery cell and can make the secondary battery cell have high energy density and high reliability.

[0006] In a first aspect, the present disclosure provides a separator, comprising a porous base film and a porous coating layer located on at least one side of the porous base film, the porous coating layer comprising organic particles, the organic particles comprising first organic particles and second organic particles; the first organic particles and the second organic particles both have a glass transition temperature T g , and the glass transition temperature T g of the first organic particles is different from the glass transition temperature T g of the second organic particles; or, the first organic particles have a glass transition temperature T g , and the second organic particles do not have a glass transition temperature T g below 300°C.

[0007] The densities of the first organic particles and the second organic particles are small, so that the secondary battery cell using the separator of the present disclosure can have higher energy density. By making the porous coating layer of the separator simultaneously comprise first organic particles and second organic particles with different T g , the organic particles with large T g or the organic particles without T gThe organic particles can improve the heat resistance of the porous coating as a whole, reduce the thermal shrinkage of the separator as a whole, and improve the reliability of the secondary battery cell. At the same time, during the charging and discharging process of the secondary battery cell, due to abnormal environmental factors, internal factors, such as the increase of by-products, etc., the temperature inside the secondary battery cell may abnormally rise. By making the porous coating of the separator include T g The different first organic particles and second organic particles, when the temperature inside the secondary battery cell reaches T g The glass transition temperature of the small organic particles, at this time, under the dual action of the electrode assembly expansion force and high temperature, the organic particles will deform and flatten, thereby to a certain extent, hinder the ion transmission between the positive and negative electrodes, and hinder the continuous rise of the temperature inside the secondary battery cell, thereby improving the thermal reliability of the secondary battery cell and reducing the risk of thermal runaway of the secondary battery cell. Therefore, the separator of the present disclosure can make the secondary battery cell have high energy density and high reliability.

[0008] In some embodiments, the first organic particles include at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a cross-linked polymer.

[0009] In some embodiments, the second organic particles include at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a cross-linked polymer.

[0010] In some embodiments, the first organic particles and the second organic particles are different in substance.

[0011] In some embodiments, the glass transition temperature T g Below 165°C, optionally 110°C-165°C.

[0012] The glass transition temperature T g Within the above range, when the temperature inside the secondary battery cell abnormally rises, under the dual action of the electrode assembly expansion force and high temperature, the organic particles will deform and flatten, thereby to a certain extent, hinder the ion transmission between the positive and negative electrodes, and hinder the continuous rise of the temperature inside the secondary battery cell, thereby improving the thermal reliability of the secondary battery cell and reducing the risk of thermal runaway of the secondary battery cell.

[0013] In some embodiments, the first organic particles include one or more of cross-linked styrene-based organic particles, polycarbonate-based organic particles, polymethyl acrylate methyl ester-based organic particles, polyformaldehyde-based organic particles, polyamide-based organic particles, styrene-acrylonitrile copolymer, polyphenylene sulfide-based organic particles, polyether ether ketone-based organic particles.

[0014] In some embodiments, the first organic particles comprise crosslinked styrene-based organic particles, which comprise styrene or styrene derivative structural units and crosslinking structural units.

[0015] Optionally, the styrene or styrene derivative structural units comprise one or more of styrene structural units, 1-methyl-1-styrene structural units, 4-methylstyrene structural units, 2-methylstyrene structural units, 2,4-dimethylstyrene structural units, 2,5-dimethylstyrene structural units.

[0016] Optionally, the crosslinking structural units comprise one or more of divinylbenzene structural units, ethylene glycol dimethacrylate structural units, pentaerythritol tetraacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, tripropylene glycol diacrylate structural units, N,N-methylenebisacrylamide structural units, N,N'-vinylbisacrylamide structural units, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural units, trisallyl isocyanurate structural units.

[0017] In some embodiments, the first organic particles comprise crosslinked styrene-based organic particles, which have no melting point. The crosslinked styrene-based organic particles have no melting point, which means that they 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.

[0018] In some embodiments, the first organic particles comprise crosslinked styrene-based organic particles, which have an initial thermal weight loss temperature T 3d of 335℃-388℃. The crosslinked styrene-based organic particles have an initial thermal weight loss temperature T 3d of 335℃-388℃, which means that they have good 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.

[0019] In some embodiments, the first organic particles comprise cross-linked styrene-based organic particles, and the cross-linked styrene-based organic particles have no oxidation peak in a cyclic voltammogram of the first cycle in a voltage range of 2.5 V to 4.4 V. The cross-linked styrene-based organic particles having no oxidation peak in a cyclic voltammogram of the first cycle in a voltage range of 2.5 V to 4.4 V indicates that the cross-linked styrene-based organic particles are stable in the voltage range of 2.5 V to 4.4 V. Therefore, the cross-linked styrene-based organic particles of the present disclosure have good electrochemical stability, can be applied in high-voltage secondary battery cells, improve the working voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity release characteristics at high voltage.

[0020] In some embodiments, the first organic particles comprise cross-linked styrene-based organic particles, and the cross-linked styrene-based organic particles have a swelling degree less than or equal to 3% when 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. The cross-linked styrene-based organic particles have a small swelling degree in the organic solvent, and have high structural stability during long-term use of the secondary battery cell, thereby improving the problem of decrease in air permeability of the separator during use.

[0021] In some embodiments, the first organic particles comprise cross-linked styrene-based organic particles, and the cross-linked styrene-based organic particles have a dissolution rate less than or equal to 3% when 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. The cross-linked styrene-based organic particles have a small dissolution rate in the organic solvent, and have high structural stability during long-term use of the secondary battery cell, and have high chemical stability in the electrolyte, thereby enabling the secondary battery cell to have longer cycle stability.

[0022] In some embodiments, the second organic particles have a glass transition temperature T g , and the glass transition temperature T g of the second organic particles is greater than the glass transition temperature T g of the first organic particles.

[0023] In some embodiments, the glass transition temperature T g of the second organic particles is 170°C-290°C.

[0024] Optionally, the second organic particles comprise one or more of polyimide-based organic particles, polysulfone-based organic particles, polyether sulfone-based organic particles, polyphenylene sulfone-based organic particles, polybenzimidazole-based organic particles, polyamide-imide-based organic particles, and polyethyleneimine-based organic particles.

[0025] In some embodiments, the second organic particles have no glass transition temperature Tg below 300℃ g , and the second organic particles include at least one of a cross-linked polymer or a thermosetting resin polymer.

[0026] Optionally, the cross-linked polymer includes silicon-containing organic cross-linked resin particles.

[0027] Optionally, the thermosetting resin polymer includes one or more of phenol resin-based organic particles, polymer particles containing triazine ring structure units, epoxy resin-based organic particles, unsaturated polyester resin-based organic particles, urea-formaldehyde resin-based organic particles, furan resin-based organic particles.

[0028] In some embodiments, the silicon-containing organic cross-linked resin particles contain benzene ring structures.

[0029] In some embodiments, the silicon-containing organic cross-linked resin particles are network structures formed with carbon-carbon bonds as the main chain, and the side chains contain siloxane structures and benzene ring structures.

[0030] In some embodiments, the silicon-containing organic cross-linked resin particles include cross-linking structure units, and the cross-linking structure units include divinyl benzene structure units.

[0031] Optionally, the cross-linking structure units further include one or more of divinyl glycol diethyl ether structure units, triethylene glycol diethyl ether structure units, maleic acid diallyl ester structure units, ethylene glycol dimethyl acrylate 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 trimethyl acrylate structure units, tetraethylene glycol dimethyl acrylate structure units, tripropylene glycol diacrylate structure units, 2,2,4-trimethyl adipic acid bis[2-ethylaziridine] structure units, 1,1-sebacic acid bis[2-methylaziridine] structure units, 1,1-(1,3-phenylene dicarbonyl) bis[2-methylaziridine] structure units, trimethylolpropane tri(2-methyl-1-aziridinyl propionate) structure units, trimethylolpropane-tris[3-(2-methylaziridinyl) propionate] structure units, pentaerythritol tri(3-aziridinyl) propionate structure units.

[0032] In some embodiments, the silicon-containing organic cross-linked resin particles have no melting point. The silicon-containing organic cross-linked resin particles have no melting point, indicating that they 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 isolation film, and improve the reliability of the secondary battery cell.

[0033] In some embodiments, the starting thermal weight loss temperature T 3d is 240-330°C. The starting thermal weight loss temperature T 3d of the silicon-containing organic crosslinked resin particles is high, indicating that the thermal stability is good, so that it 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.

[0034] In some embodiments, the cyclic voltammogram of the silicon-containing organic crosslinked resin particles after the first cycle does not have an oxidation peak in the voltage range of 2.5-4.4 V. The cyclic voltammogram of the silicon-containing organic crosslinked resin particles after the first cycle does not have an oxidation peak in the voltage range of 2.5-4.4 V, which indicates that the silicon-containing organic crosslinked resin particles are stable in the voltage range of 2.5-4.4 V. Therefore, the silicon-containing organic crosslinked resin particles of the present disclosure have good electrochemical stability, can be applied in high-voltage secondary battery cells, improve the operating voltage and energy density of the secondary battery cell, and also enable the secondary battery cell to have good capacity performance characteristics at high voltage.

[0035] In some embodiments, the swelling degree of the silicon-containing organic crosslinked resin particles in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 and immersed at 60°C for 7 days is less than or equal to 3%. The silicon-containing organic crosslinked resin particles have a small swelling degree in organic solvents, and have high structural stability during long-term use of the secondary battery cell, thereby improving the problem of decreased air permeability of the separator film during use.

[0036] In some embodiments, the dissolution rate of the silicon-containing organic crosslinked resin particles in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 and immersed at 60°C for 7 days is less than or equal to 3%. The silicon-containing organic crosslinked resin particles have a small dissolution rate in organic solvents, have high structural stability during long-term use of the secondary battery cell, and have high chemical stability in electrolyte, thereby enabling the secondary battery cell to have longer cycle stability.

[0037] In some embodiments, the phenolic resin-based organic particles are thermosetting resol resin.

[0038] In some embodiments, the phenolic resin-based organic particles have no melting point. The phenolic resin-based organic particles have no melting point, indicating that they have good heat resistance and thermal stability, so that they 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.

[0039] In some embodiments, the starting thermal weight loss temperature T 3d of the phenolic resin-based organic particles is 290-350°C. The starting thermal weight loss temperature T3d High, which indicates that it has good thermal stability, thereby better resisting thermal shrinkage of the porous base film, improving the heat resistance of the separation film, and improving the reliability of the secondary battery cell.

[0040] In some embodiments, the phenolic resin-based organic particles do not have an oxidation peak in the cyclic voltammetry curve of the first cycle in a voltage range of 2.5V to 4.4V. The phenolic resin-based organic particles do not have an oxidation peak in the cyclic voltammetry curve of the first cycle in a voltage range of 2.5V to 4.4V, which indicates that the phenolic resin-based organic particles are stable in a voltage range of 2.5V to 4.4V. Therefore, the phenolic resin-based organic particles of the present disclosure have good electrochemical stability, can be applied to high-voltage secondary battery cells, improve the operating voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity performance characteristics at high voltage.

[0041] In some embodiments, the phenolic resin-based organic particles have a swelling degree of less than or equal to 3% when soaked in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days. The phenolic resin-based organic particles have a low swelling degree in organic solvents, have high structural stability during long-term use of the secondary battery cell, and thus improve the problem of decreased air permeability of the separation film during use.

[0042] In some embodiments, the phenolic resin-based organic particles have a dissolution rate of less than or equal to 3% when soaked in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days. The phenolic resin-based organic particles have a low dissolution rate in organic solvents, have high structural stability during long-term use of the secondary battery cell, and have high chemical stability in electrolyte, thereby enabling the secondary battery cell to have longer cycle stability.

[0043] In some embodiments, the polymer particles containing triazine ring structural units include a bridging structure connecting the triazine ring structural units.

[0044] In some embodiments, 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.

[0045] In some embodiments, the polymer particles containing triazine ring structural units further have a substituent group on the triazine ring structural units, and the substituent group includes one or a combination of two or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, a hydroxyl group, and a halogen.

[0046] In some embodiments, the polymer particles containing triazine ring structural units include 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-polycarboxylic acid polymers and derivatives thereof, etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof.

[0047] In some embodiments, the melamine formaldehyde polymers and derivatives thereof include one or more of melamine formaldehyde, benzoguanamine formaldehyde, melamine- benzoguanamine formaldehyde, melamine-(2,4-diamino-l,3,5-triazine) formaldehyde, melamine-(6-methyl-l,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-l,3,5-triazine) formaldehyde, trihydrazinotriazine formaldehyde, melamine-(2-amino-4-methylamino-l,3,5-triazine) formaldehyde, melamine-(2,4-diamino-6-dimethylamino-l,3,5-triazine) formaldehyde.

[0048] In some embodiments, the etherified melamine formaldehyde polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzoguanamine formaldehyde, butyl etherified benzoguanamine formaldehyde.

[0049] In some embodiments, the etherified melamine formaldehyde-polyol polymers and derivatives thereof include 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.

[0050] In some embodiments, the etherified melamine formaldehyde-polycarboxylic acid polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde-oxalic acid polymer, methyl etherified melamine formaldehyde-malic acid polymer, methyl etherified melamine formaldehyde-succinic acid polymer, methyl etherified melamine formaldehyde-citric acid polymer, methyl etherified melamine formaldehyde-terephthalic acid polymer, methyl etherified melamine formaldehyde-phthalic acid polymer, butyl etherified melamine formaldehyde-oxalic acid polymer, butyl etherified melamine formaldehyde-malic acid polymer, butyl etherified melamine formaldehyde-citric acid polymer, butyl etherified melamine formaldehyde-terephthalic acid polymer, butyl etherified melamine formaldehyde-phthalic acid polymer.

[0051] In some embodiments, the etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyl etherified melamine formaldehyde-glycolamide polymer, a methyl etherified melamine formaldehyde-malonyl amide polymer, a methyl etherified melamine formaldehyde-iso-phthalimide polymer, a butyl etherified melamine formaldehyde-glycolamide polymer.

[0052] In some embodiments, the polymer particles containing triazine ring structural units have no melting point. The polymer particles containing triazine ring structural units have no melting point, which indicates that they 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.

[0053] In some embodiments, the polymer particles containing triazine ring structural units have an initial thermal weight loss temperature T 3d of 290°C-345°C. The polymer particles containing triazine ring structural units have an initial thermal weight loss temperature T 3d of 290°C-345°C, which indicates that they have good 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.

[0054] In some embodiments, the polymer particles containing triazine ring structural units have no oxidation peak in the cyclic voltammetry curve of the first cycle in the voltage range of 2.5V to 4.4V. The polymer particles containing triazine ring structural units have no oxidation peak in the cyclic voltammetry curve of the first cycle in the voltage range of 2.5V to 4.4V, which indicates that the polymer particles containing triazine ring structural units are stable in the voltage range of 2.5V to 4.4V. Therefore, the polymer particles containing triazine ring structural units of the present disclosure have good electrochemical stability, can be applied in high-voltage secondary battery cells, improve the operating voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity performance characteristics at high voltage.

[0055] In some embodiments, the polymer particles containing triazine ring structural units have a swelling degree of less than or equal to 3% when immersed in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at a constant temperature of 60°C for 7 days. The polymer particles containing triazine ring structural units have a small swelling degree in organic solvents, and have high structural stability during long-term use of the secondary battery cell, thereby improving the problem of decreased air permeability of the separator film during use.

[0056] In some embodiments, the polymer particles containing the triazine ring structural unit have a dissolution rate of less than or equal to 3% 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. The polymer particles containing the triazine ring structural unit have a low dissolution rate in the organic solvent, have high structural stability during long-term use of the secondary battery cell, and have high chemical stability in the electrolyte, thereby allowing the secondary battery cell to have long cycle stability.

[0057] In some embodiments, the volume distribution particle size Dv50 of the organic particles is 80 nm-800 nm. The volume distribution particle size Dv50 of the organic particles in the above range is advantageous for the separator film to have good heat resistance and air permeability.

[0058] In some embodiments, the mass ratio of the first organic particles to the second organic particles is 1:99 to 50:50, which can be 5:95 to 25:75.

[0059] The mass ratio of the first organic particles to the second organic particles in the above range is advantageous for the secondary battery cell to have higher reliability.

[0060] In some embodiments, the porous coating further comprises a binder.

[0061] In some embodiments, the thickness of the porous coating is 0.5 μm-5 μm.

[0062] In a second aspect, the present disclosure provides a method for preparing the separator film of the first aspect, comprising the following steps: providing a porous base film; providing a slurry comprising first organic particles, second organic particles, and a binder; coating the slurry on at least one side of the porous base film to obtain the separator film after drying.

[0063] In a third aspect, the present disclosure provides a secondary battery cell comprising the separator film of the first aspect of the present disclosure or the separator film prepared by the method of the second aspect.

[0064] In a fourth aspect, the present disclosure provides a battery device comprising a plurality of secondary battery cells of the third aspect of the present disclosure.

[0065] In a fifth aspect, the present disclosure provides an electric device comprising the secondary battery cell of the third aspect of the present disclosure or the battery device of the fourth aspect of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0066] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments of the present disclosure. Obviously, the drawings described below are only some of the embodiments of the present disclosure, and for those skilled in the art, other drawings can also be obtained from the drawings without creative labor.

[0067] FIG. 1 shows a schematic diagram of a secondary battery cell according to some embodiments of the present disclosure.

[0068] FIG. 2 shows a schematic diagram of an electric device according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0069] Hereinafter, specific embodiments of the present disclosure, i.e., a separator and a method for manufacturing the same, a secondary battery cell, a battery device, and an electric device, will be described in detail with appropriate reference to the accompanying 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 to those skilled in the art, repeated descriptions of substantially identical configurations, 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 to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0070] The ranges disclosed by the present disclosure are defined in the form of lower limit and upper limit, and a given range is defined by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The ranges defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. In addition, if a minimum range value of 1 and 2 is listed, and if a maximum range value of 3, 4, and 5 is listed, 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" represents a shorthand notation for any real combination of integers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed herein, and "0-5" is just a shorthand notation for these numerical combinations. In addition, when a parameter is stated to be ≥2 integers, it is equivalent to disclose that the parameter is, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0071] 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 content of the present disclosure.

[0072] 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 shall be considered to be included in the disclosure of the present disclosure.

[0073] 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) performed in sequence, or steps (b) and (a) performed 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.

[0074] 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 specific order or primary and secondary relationship.

[0075] In the present disclosure, the terms "a plurality of" and "a plurality of" refer to two or more.

[0076] In the description of the embodiments of the present disclosure, unless otherwise specified, 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 "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0077] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25℃.

[0078] 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.

[0079] The secondary battery cell provided by embodiments of the present disclosure can include, but is not limited to, a lithium battery cell, a sodium battery cell, for example, a lithium-ion battery cell, a sodium-ion battery cell, a lithium metal battery cell, a sodium metal battery cell, etc.

[0080] The secondary battery cell provided by embodiments of the present disclosure includes an electrode assembly. The electrode assembly can be in a jelly-roll structure or a stacked structure, and embodiments of the present disclosure are not limited in this regard. The secondary battery cell further includes an outer package, which can be used to encapsulate 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 pouch-type soft package. The soft package can be made of plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0081] The battery apparatus mentioned in 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 connection through a busbar component.

[0082] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of secondary battery cells.

[0083] 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 into an independent module. As an example, the battery module can be formed by bundling a plurality of secondary battery cells with a cable tie.

[0084] In some embodiments, the battery apparatus can be a battery pack, which includes a box and one or more battery cell assemblies housed in the box.

[0085] As an example, the battery cell assembly can be a battery module, which can be housed in the box by fixing the battery module in the box.

[0086] As an example, the battery cell assembly can also be housed in the box by directly fixing a plurality of secondary battery cells in the box.

[0087] As an example, the box can include a first box and a second box. The first box and the second box are fastened so that an enclosed space is formed inside the box to accommodate the battery cell assembly. Here, enclosed means covered or closed, which can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0088] As an example, the box can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected with the frame, so that an enclosed space is formed inside the box to accommodate the battery cell assembly.

[0089] In some embodiments, the box can be part of a chassis structure of a vehicle. For example, part of the box can be at least part of a floor of the vehicle, or part of the box can be at least part of a cross beam and a longitudinal beam of the vehicle.

[0090] 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, but not limited to, mobile devices (such as mobile phones, tablets, laptops, etc.), electric vehicles (such as 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 battery devices are used to store or provide electric energy.

[0091] 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.

[0092] In the context of the present disclosure, the "organic particles" mainly play a role in improving the heat resistance in the porous coating of the separator film, and almost have no adhesion.

[0093] The separator film is an important component for supporting the secondary battery cell to complete the electrochemical process of charging and discharging. The commonly used separator film is mostly a polyolefin film. However, the polyolefin film has poor heat resistance and is easy to soften or melt at high temperature, which may cause short circuit of the secondary battery cell. In order to improve the heat resistance of the separator film, a porous coating layer is usually coated on the separator film to improve the heat resistance of the separator film. Inorganic particles such as boehmite and aluminum oxide are currently commonly used heat-resistant fillers. However, the density of such heat-resistant fillers is relatively large, and the mass is large under the same packing volume, which affects the energy density of the secondary battery cell.

[0094] Based on this, the embodiments of the present disclosure provide a separator film used in a secondary battery cell, which can make the secondary battery cell have high energy density and high reliability.

[0095] The separator film of the present disclosure includes a porous base film and a porous coating layer located on at least one side of the porous base film. The porous coating layer includes organic particles, and the organic particles include first organic particles and second organic particles. The first organic particles and the second organic particles both have a glass transition temperature T g , and the glass transition temperature T g of the first organic particles is different from the glass transition temperature T g of the second organic particles; or the first organic particles have a glass transition temperature Tg Furthermore, the second organic particle does not have a glass transition temperature T below 300°C. g .

[0096] Both the porous base membrane and the porous coating have a porous structure, which gives the separator good air permeability and facilitates the passage of ions.

[0097] The first and second organic particles have low densities, which allows the secondary battery cell using the separator of this disclosure to have a higher energy density.

[0098] By making the porous coating of the separator simultaneously include T g Different first organic particles and second organic particles, wherein T g Large organic particles or those without T g Organic particles can improve the overall heat resistance of the porous coating, reduce the overall thermal shrinkage of the separator, and improve the reliability of the secondary battery cell. Meanwhile, during the charging and discharging process of the secondary battery cell, abnormal environmental factors and internal factors, such as an increase in byproducts, may cause an abnormal rise in the internal temperature of the secondary battery cell. By including T in the porous coating of the separator... g Different first and second organic particles reach a temperature of T inside the secondary battery cell. g At the glass transition temperature of small organic particles, under the combined effects of the expansion force of the electrode assembly and high temperature, the organic particles will deform and flatten. This can, to a certain extent, hinder ion transport between the positive and negative electrodes and prevent the internal temperature of the secondary battery cell from rising continuously. In this way, the thermal reliability of the secondary battery cell can be improved and the risk of thermal runaway of the secondary battery cell can be reduced.

[0099] Therefore, the separator disclosed herein enables secondary battery cells to possess both high energy density and high reliability.

[0100] In some embodiments, the first organic particle may include at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a crosslinked polymer.

[0101] In some embodiments, the second organic particles may include at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a crosslinked polymer.

[0102] In some embodiments, the first organic particles and the second organic particles are of different types of substances.

[0103] In some embodiments, the glass transition temperature T of the first organic particle g Below 165℃.

[0104] Optionally, the glass transition temperature T of the first organic particle gmay be 110°C, 112°C, 114°C, 116°C, 118°C, 120°C, 122°C, 124°C, 126°C, 128°C, 130°C, 132°C, 134°C, 136°C, 138°C, 140°C, 142°C, 144°C, 146°C, 148°C, 150°C, 152°C, 154°C, 156°C, 158°C, 160°C, 162°C, 165°C, or a range consisting of any of the aforementioned values.

[0105] The glass transition temperature T of the first organic particles g Within the above range, when the internal temperature of the secondary battery cell abnormally rises, the electrode assembly can be deformed and flattened under the dual action of the expansion force of the electrode assembly and the high temperature, thereby playing a role of hindering ion transport between the positive and negative electrodes and hindering the continuous rise of the internal temperature of the secondary battery cell, and further improving the thermal reliability of the secondary battery cell and reducing the risk of thermal runaway of the secondary battery cell.

[0106] In some embodiments, the first organic particles can include one or more of crosslinked styrene-based organic particles, polycarbonate-based organic particles, polymethyl acrylate methyl ester-based organic particles, polyformaldehyde-based organic particles, polyamide-based organic particles, styrene-acrylonitrile copolymer, polyphenylene sulfide-based organic particles, polyether ether ketone-based organic particles.

[0107] The crosslinked styrene-based 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), chloroform at 25°C, i.e., not soluble in the mobile phase for gel permeation chromatography testing, nor can the molecular weight of the crosslinked styrene-based organic particles be tested by gel permeation chromatography.

[0108] In some embodiments, the crosslinked styrene-based organic particles include styrene or styrene derivative structural units and crosslinking structural units.

[0109] The crosslinking structural unit of the crosslinked styrene-based organic particles refers to a structural unit for connecting the styrene or styrene derivative structural unit.

[0110] Optionally, the styrene or styrene derivative structural unit can 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, a 2,5-dimethylstyrene structural unit.

[0111] Optionally, the cross-linking structural unit can include 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, and a trimeric isocyanuric acid triallyl ester structural unit.

[0112] In some embodiments, the cross-linked styrene-based organic particles have no melting point.

[0113] The cross-linked styrene-based organic particles of the present disclosure have no melting point, which indicates that they 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.

[0114] In some embodiments, the cross-linked styrene-based organic particles have an initial thermal weight loss temperature T 3d may be 335°C-388°C.

[0115] The cross-linked styrene-based organic particles have an initial thermal weight loss temperature T 3d is high, which indicates that they have good 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.

[0116] In some embodiments, the cross-linked styrene-based organic particles have no oxidation peak in the cyclic voltammetry curve of the first cycle in the voltage range of 2.5V to 4.4V.

[0117] The cross-linked styrene-based organic particles have no oxidation peak in the cyclic voltammetry curve of the first cycle in the voltage range of 2.5V to 4.4V, which indicates that the cross-linked styrene-based organic particles are stable in the voltage range of 2.5V to 4.4V. Therefore, the cross-linked styrene-based organic particles of the present disclosure have good electrochemical stability, can be applied in high-voltage secondary battery cells, improve the working voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity performance characteristics at high voltage.

[0118] In some embodiments, the cross-linked styrene-based organic particles have a swelling degree of less than or equal to 3% when immersed in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days.

[0119] The crosslinked styrene-based organic particles have a low swelling degree in organic solvents, have a high structural stability during long-term use of the secondary battery cell, and thus improve a problem of a decrease in the air permeability of the separator during use.

[0120] In some embodiments, the crosslinked styrene-based organic particles have a dissolution rate of 3% or less 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.

[0121] The crosslinked styrene-based organic particles have a low dissolution rate in organic solvents, have a high structural stability during long-term use of the secondary battery cell, and have a high chemical stability in the electrolyte, and thus can provide a secondary battery cell with a longer cycle stability.

[0122] In some embodiments, the second organic particles have a glass transition temperature T g , and the glass transition temperature T g of the second organic particles is greater than the glass transition temperature T g of the first organic particles.

[0123] In some embodiments, the glass transition temperature T g of the second organic particles can be 170°C to 290°C.

[0124] Optionally, the second organic particles can include one or more of a polyimide-based organic particle, a polysulfone-based organic particle, a polyethersulfone-based organic particle, a polyphenylenesulfone-based organic particle, a polybenzimidazole-based organic particle, a polyamide-imide-based organic particle, and a polyethyleneimine-based organic particle.

[0125] In some embodiments, the second organic particles do not have a glass transition temperature T g at 300°C or less, and the second organic particles can include at least one of a crosslinked polymer or a thermosetting resin polymer.

[0126] Optionally, the crosslinked polymer can include a silicon-containing organic crosslinking resin particle.

[0127] Optionally, the thermosetting resin polymer can include one or more of a phenol resin-based organic particle, a polymer particle including a triazine ring structural unit, an epoxy resin-based organic particle, an unsaturated polyester resin-based organic particle, a urea-formaldehyde resin-based organic particle, and a furan resin-based organic particle.

[0128] Optionally, the second organic particles can include one or more of a silicon-containing organic crosslinking resin particle, a phenol resin-based organic particle, and a polymer particle including a triazine ring structural unit.

[0129] [Silicon-containing organic crosslinking resin particle]

[0130] In some embodiments, the silicon-containing organic crosslinking resin particles contain a benzene ring structure.

[0131] Currently, existing silicon resins are mainly formed by hydrolysis of hydrolyzable siloxanes to form a prepolymer, and then cured to obtain, and have poor heat resistance. The silicon-containing organic crosslinking resin particles of the present disclosure contain a benzene ring structure, which has strong rigidity and can make the silicon-containing organic crosslinking resin particles have good heat resistance. By using the silicon-containing organic crosslinking resin particles containing a benzene ring structure in the porous coating of the separator film, a better force can be generated to resist the shrinkage of the porous base film, thereby improving the overall heat shrinkage of the separator film, improving the heat resistance of the separator film, and improving the reliability of the secondary battery cell.

[0132] Optionally, the silicon-containing organic crosslinking resin particles are network structures formed with carbon-carbon bonds as the main chain, and the side chains contain siloxane structures and benzene ring structures.

[0133] In some embodiments, the silicon-containing organic crosslinking resin particles include a crosslinking structure unit, which can include a divinylbenzene structure unit.

[0134] Optionally, the crosslinking structure unit can include one or more of a divinylbenzene structure unit and a diethylene glycol divinyl ether structure unit, a triethylene glycol divinyl ether structure unit, a maleic acid diallyl ester structure unit, an ethylene glycol dimethyl acrylate structure unit, a 1,4-butanediol diacrylate structure unit, a 1,6-hexanediol diacrylate structure unit, a 1,8-octanediol diacrylate structure unit, a trimethylolpropane triacrylate structure unit, a pentaerythritol trimethacrylate structure unit, a tetraethylene glycol dimethacrylate structure unit, a tripropylene glycol diacrylate structure unit, a 2,2,4-trimethylhexanedioic acid bis[2-ethylaziridine] structure unit, a 1,1-nonanedioic acid bis[2-methylaziridine] structure unit, a 1,1-(1,3-phenylenedicarbonyl) bis[2-methylaziridine] structure unit, a trimethylolpropane tris(2-methyl-1-aziridinyl propionate) structure unit, a trimethylolpropane-tris[3-(2-methylaziridinyl) propionate] structure unit, and a pentaerythritol tris(3-aziridinyl) propionate structure unit.

[0135] The silicon-containing organic crosslinking resin particles of the present disclosure are neither soluble in water nor in organic solvents such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), chloroform at 25°C, i.e. not soluble in the mobile phase for gel permeation chromatography testing, and the molecular weight of the silicon-containing organic crosslinking resin particles cannot be tested by gel permeation chromatography.

[0136] In some embodiments, the silicon-containing organic crosslinking resin particles have no melting point.

[0137] The silicon-containing organic crosslinked resin particles of the present disclosure have no melting point, indicating that they 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.

[0138] In some embodiments, the silicon-containing organic crosslinked resin particles have a starting thermal weight loss temperature T 3d may be 240°C to 330°C.

[0139] The silicon-containing organic crosslinked resin particles have a starting thermal weight loss temperature T 3d that is high, indicating that they have good 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.

[0140] In some embodiments, the cyclic voltammogram of the silicon-containing organic crosslinked resin particles in the first cycle has no oxidation peak in the voltage range of 2.5V to 4.4V.

[0141] The cyclic voltammogram of the silicon-containing organic crosslinked resin particles in the first cycle has no oxidation peak in the voltage range of 2.5V to 4.4V, which indicates that the silicon-containing organic crosslinked resin particles are stable in the voltage range of 2.5V to 4.4V. Therefore, the silicon-containing organic crosslinked resin particles of the present disclosure have good electrochemical stability, can be applied in high-voltage secondary battery cells, improve the working voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity performance characteristics at high voltage.

[0142] In some embodiments, the silicon-containing organic crosslinked resin particles have a swelling degree of less than or equal to 3% 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.

[0143] The silicon-containing organic crosslinked resin particles have a low swelling degree in organic solvents, and have high structural stability during long-term use of the secondary battery cell, thereby improving the problem of decreased air permeability of the separator film during use.

[0144] In some embodiments, the silicon-containing organic crosslinked resin particles have a dissolution rate of less than or equal to 3% 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.

[0145] The silicon-containing organic crosslinked resin particles have a low dissolution rate in organic solvents, and have high structural stability during long-term use of the secondary battery cell, and high chemical stability in electrolyte, thereby enabling the secondary battery cell to have longer cycle stability.

[0146] [Phenolic resin-based organic particles]

[0147] The phenolic resin-based 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), chloroform at 25°C, i.e. insoluble in the mobile phase for gel permeation chromatography test, nor can the molecular weight of the phenolic resin-based organic particles be tested by gel permeation chromatography.

[0148] In some embodiments, the phenolic resin-based organic particles are thermosetting resins.

[0149] In some embodiments, the phenolic resin-based organic particles are thermosetting resol.

[0150] In some embodiments, the phenolic resin-based organic particles have no melting point.

[0151] The phenolic resin-based organic particles of the present disclosure have no melting point, indicating that they 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.

[0152] In some embodiments, the phenolic resin-based organic particles have an initial thermal weight loss temperature T 3d may be 290°C-350°C.

[0153] The phenolic resin-based organic particles have an initial thermal weight loss temperature T 3d is high, indicating that they have good 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.

[0154] In some embodiments, the cyclic voltammogram of the phenolic resin-based organic particles in the first cycle has no oxidation peak in the voltage range of 2.5V to 4.4V.

[0155] The cyclic voltammogram of the phenolic resin-based organic particles in the first cycle has no oxidation peak in the voltage range of 2.5V to 4.4V, which indicates that the phenolic resin-based organic particles are stable in the voltage range of 2.5V to 4.4V. Therefore, the phenolic resin-based organic particles of the present disclosure have good electrochemical stability, can be applied in high-voltage secondary battery cells, improve the working voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity release characteristics at high voltage.

[0156] In some embodiments, the swelling degree of the phenolic resin-based 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 can be less than or equal to 3%.

[0157] The phenol resin-based organic particles have a low degree of swelling in organic solvents, high structural stability during long-term use of the secondary battery cell, and thus improve the problem of a decrease in the gas permeability of the separator during use.

[0158] In some embodiments, the phenol resin-based organic particles can have a dissolution rate of 3% or less 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.

[0159] The phenol resin-based organic particles have a low degree of swelling in organic solvents, high structural stability during long-term use of the secondary battery cell, and thus improve the problem of a decrease in the gas permeability of the separator during use.

[0160] [Polymer particles containing a triazine ring structure unit]

[0161] The triazine ring structure is rigid, and thus the polymer particles have good heat resistance.

[0162] The polymer particles containing a triazine ring structure unit according to the present disclosure include a bridging structure connecting the triazine ring structure units.

[0163] The polymer particles containing a triazine ring structure unit have a plurality of triazine ring structure units in the molecular structure, and the bridging structure refers to a group connecting the triazine ring structure units, and each bridging structure is the same or different.

[0164] Optionally, the bridging structure can include 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.

[0165] More optionally, the bridging structure can include one or a combination of two or more of a methylene group, a methylene ether group, and a methylene amine group.

[0166] In some embodiments, the polymer particles containing a triazine ring structure unit can further have a substituent on the triazine ring structure unit, and the substituent can include one or a combination of two or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, a hydroxyl group, and a halogen.

[0167] In some embodiments, the polymer particles containing a triazine ring structure unit can include at least one of a melamine formaldehyde-based polymer and a derivative thereof, an etherified melamine formaldehyde-based polymer and a derivative thereof, an etherified melamine formaldehyde-polyol polymer and a derivative thereof, an etherified melamine formaldehyde-polybasic acid polymer and a derivative thereof, and an etherified melamine formaldehyde-polyamine amide polymer and a derivative thereof.

[0168] In some embodiments, the melamine formaldehyde-based polymer and the derivative thereof can include a melamine formaldehyde polymer and a derivative thereof.

[0169] Optionally, the melamine formaldehyde polymers and derivatives thereof can include one or more of melamine formaldehyde, benzoguanamine formaldehyde, melamine- benzoguanamine formaldehyde, melamine-(2,4-diamino-l,3,5-triazine) formaldehyde, melamine-(6-methyl-l,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-l,3,5-triazine) formaldehyde, trihydrazinotriazine formaldehyde, melamine-(2-amino-4-methylamino-l,3,5-triazine) formaldehyde, melamine-(2,4-diamino-6-dimethylamino-l,3,5-triazine) formaldehyde.

[0170] In some embodiments, the etherified melamine formaldehyde polymers and derivatives thereof can include etherified melamine formaldehyde polymers and derivatives thereof.

[0171] In some embodiments, the etherified melamine formaldehyde polymers and derivatives thereof can include methyl etherified melamine formaldehyde polymers and derivatives thereof, ethyl etherified melamine formaldehyde polymers and derivatives thereof, butyl etherified melamine formaldehyde polymers and derivatives thereof, methyl-butyl mixed etherified melamine formaldehyde polymers and derivatives thereof.

[0172] Optionally, the etherified melamine formaldehyde polymers and derivatives thereof can include methyl etherified melamine formaldehyde polymers and derivatives thereof, ethyl etherified melamine formaldehyde polymers and derivatives thereof, butyl etherified melamine formaldehyde polymers and derivatives thereof, methyl-butyl mixed etherified melamine formaldehyde polymers and derivatives thereof.

[0173] The etherified melamine formaldehyde polymers and derivatives thereof can include one or more of partially etherified melamine formaldehyde polymers and derivatives thereof, fully etherified melamine formaldehyde polymers and derivatives thereof. Optionally, the etherified melamine formaldehyde polymers and derivatives thereof can include fully etherified melamine formaldehyde polymers and derivatives thereof.

[0174] In some embodiments, the etherified melamine formaldehyde polymers and derivatives thereof can include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzoguanamine formaldehyde, butyl etherified benzoguanamine formaldehyde.

[0175] The etherified melamine formaldehyde-polyol polymers and derivatives thereof refer to the etherified melamine formaldehyde resin and polyol high temperature crosslinking and curing reaction products. Optionally, the molar ratio of the etherified melamine formaldehyde resin and polyol can be 1:2-1:6.

[0176] In some embodiments, the polyol can include one or more of dihydric alcohol, trihydric alcohol, tetrahydric alcohol. Optionally, the polyol can include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethyl butyl propylene glycol, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyol, polyester polyol. More optionally, the polyol can include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, polyvinyl alcohol, polyester polyol.

[0177] Optionally, the polyester polyol can include one or more of polyethylene adipate glycol, poly-1,4-butanediol adipate glycol, polypropylene adipate glycol, polyneopentyl glycol adipate glycol, polyneopentyl glycol-1,6-hexanediol adipate glycol, polyhexanediol adipate glycol, polycarbonate glycol, polycaprolactone glycol.

[0178] Optionally, the polyether polyol can include one or more of polypropylene oxide diol, polypropylene oxide triol, polytetrahydrofuran diol.

[0179] Optionally, the molecular weight of the polyester polyol can be below 5000, optionally below 2000.

[0180] Optionally, the molecular weight of the polyether polyol can be below 5000, optionally below 2000.

[0181] Optionally, the molecular weight of the polyvinyl alcohol can be below 5000, optionally below 2000.

[0182] In some embodiments, the etherified melamine aldehyde-polyol polymer and its derivatives can include 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.

[0183] The etherified melamine aldehyde-polybasic acid polymer and its derivatives refer to the etherified melamine aldehyde resin and polybasic acid high-temperature cross-linking and curing reaction product. Optionally, the molar ratio of the etherified melamine aldehyde resin and the polybasic acid can be 1:2-1:6.

[0184] In some embodiments, the polycarboxylic acid can include one or more of a dicarboxylic acid, a tricarboxylic acid, a tetracarboxylic acid. Optionally, the polycarboxylic acid can 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-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid. More optionally, the polycarboxylic acid can include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, terephthalic acid.

[0185] In some embodiments, the etherified melamine aldehyde-polycarboxylic acid polymer and derivatives thereof can include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malonic 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-malonic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, a butyl etherified melamine formaldehyde-phthalic acid polymer.

[0186] The etherified melamine aldehyde-polycarboxylic acid polymer and derivatives thereof refer to the etherified melamine aldehyde resin and polycarboxylic acid high temperature crosslinking and curing reaction product. Optionally, the molar ratio of the etherified melamine aldehyde resin and polycarboxylic acid can be 1:2-1:6.

[0187] In some embodiments, the polycarboxylic acid can 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-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid. More optionally, the polycarboxylic acid can include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, terephthalic acid.

[0188] In some embodiments, the etherified melamine aldehyde-polycarboxylic acid polymer and derivatives thereof can include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malonic 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-malonic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, a butyl etherified melamine formaldehyde-phthalic acid polymer.

[0189] The polymer particles containing triazine ring structure units of the present disclosure are neither soluble in water nor in organic solvents such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), chloroform at 25 °C, i.e. insoluble in the mobile phase of gel permeation chromatography test, nor the molecular weight of the polymer particles containing triazine ring structure units can be tested by gel permeation chromatography.

[0190] In some embodiments, the polymer particles containing triazine ring structural units have no melting point.

[0191] The polymer particles containing triazine ring structural units of the present disclosure have no melting point, indicating that they 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.

[0192] In some embodiments, the polymer particles containing triazine ring structural units have an initial thermal weight loss temperature T 3d of 290°C-345°C.

[0193] The polymer particles containing triazine ring structural units have an initial thermal weight loss temperature T 3d of 290°C-345°C, indicating that they have good 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.

[0194] In some embodiments, the cyclic voltammogram of the polymer particles containing triazine ring structural units in the first cycle has no oxidation peak in the voltage range of 2.5V to 4.4V.

[0195] The cyclic voltammogram of the polymer particles containing triazine ring structural units in the first cycle has no oxidation peak in the voltage range of 2.5V to 4.4V, indicating that the polymer particles containing triazine ring structural units are stable in the voltage range of 2.5V to 4.4V. Therefore, the polymer particles containing triazine ring structural units of the present disclosure have good electrochemical stability, can be applied in high-voltage secondary battery cells, improve the operating voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity performance at high voltage.

[0196] In some embodiments, the swelling degree of the polymer particles containing triazine ring structural units 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%.

[0197] The polymer particles containing triazine ring structural units have a small swelling degree in organic solvents, and have high structural stability during long-term use of the secondary battery cell, thereby improving the problem of decreased air permeability of the separator film during use.

[0198] In some embodiments, the dissolution rate of the polymer particles containing triazine ring structural units 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%.

[0199] The polymer particles containing triazine ring structural units have a small dissolution rate in organic solvents, high structural stability during long-term use of the secondary battery cell, and high chemical stability in electrolyte, thereby enabling the secondary battery cell to have a longer cycle stability.

[0200] In some embodiments, the volume distribution particle size Dv50 of the organic particles can be 80 nm-800 nm.

[0201] The volume distribution particle size Dv50 of the organic particles in the above range is advantageous for the separator film to have good heat resistance and air permeability.

[0202] In some embodiments, the mass ratio of the first organic particles to the second organic particles can be 1:99 to 50:50, for example, can be 1:99, 3:97, 5:95, 8:92, 10:90, 12:88, 15:85, 18:82, 20:80, 22:78, 25:75, 28:72, 30:70, 32:68, 35:65, 38:62, 40:60, 42:58, 45:55, 48:52, 50:50, or a range consisting of any of the above values.

[0203] The mass ratio of the first organic particles to the second organic particles in the above range can improve the reliability of the secondary battery cell.

[0204] Alternatively, the mass ratio of the first organic particles to the second organic particles can be 5:95 to 40:60, 5:95 to 35:65, 5:95 to 30:70, 5:95 to 25:75, 8:92 to 40:60, 8:92 to 35:65, 8:92 to 30:70, 8:92 to 25:75, 10:90 to 40:60, 10:90 to 35:65, 10:90 to 30:70, 10:90 to 25:75.

[0205] The mass ratio of the first organic particles to the second organic particles in the above range is advantageous for the secondary battery cell to have higher reliability.

[0206] In some embodiments, the porous coating layer further comprises a binder, for example, can comprise one or more of polyacrylate-based binder, nitrile rubber-based binder, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0207] In some embodiments, the mass content of the binder in the porous coating can be 0.5%-10%, for example, can be 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, or a range consisting of any of the aforementioned values, based on the total mass of the porous coating. Alternatively, the mass content of the binder in the porous coating can be 1%-8%.

[0208] In some embodiments, the porous coating can further include a dispersant, for example, can include but is not limited to one or more of alkylphenol polyoxyethylene ether and the like, polyacrylic dispersant, cellulose dispersant. As an example, the dispersant can include but is not limited to one or more of sodium carboxymethyl cellulose, sodium polyacrylate, ammonium polyacrylate.

[0209] In some embodiments, the separator film can further include polymer binder particles.

[0210] The "polymer binder particles" in the porous coating of the separator film play a role in improving the adhesion of the separator film to the pole piece, and have substantially no high-temperature resistance.

[0211] In some embodiments, the polymer binder particles can be embedded in the first organic particles, the second organic particles, and form protrusions on the surface of the porous coating.

[0212] In another embodiment, the porous coating of the separator film includes a heat-resistant layer and a bonding layer, the heat-resistant layer is disposed on the porous base film, the bonding layer is disposed on at least a portion of the surface of the side of the heat-resistant layer away from the porous base film, the first organic particles and the second organic particles are disposed in the heat-resistant layer, and the polymer binder particles are disposed in the bonding layer.

[0213] In another embodiment, the porous coating of the separator film includes a heat-resistant layer and a bonding layer, the heat-resistant layer is disposed on one side of the porous base film, the bonding layer is disposed on at least a portion of the surface of the other side of the porous base film, the first organic particles and the second organic particles are disposed in the heat-resistant layer, and the polymer binder particles are disposed in the bonding layer.

[0214] In some embodiments, the average particle size of the polymer binder particles can be 6 μm-18 μm.

[0215] In some embodiments, the polymer binder particles can include a vinylidene fluoride-based polymer particle, for example, a polyvinylidene fluoride (PVDF) particle and / or a copolymer particle of a vinylidene fluoride monomer and a comonomer.

[0216] The comonomer can include at least one of an olefin monomer, a fluorine-containing olefin monomer, a chlorine-containing olefin monomer, an acrylate monomer, an acrylic monomer, and a fluorine ether monomer.

[0217] Optionally, the comonomer can include at least one of 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-dioxolane), and perfluoro(2,2-dimethyl-1,3-dioxolane).

[0218] In some embodiments, the porous coating layer can have a thickness of 0.5 μm to 5 μm. The thickness of the porous coating layer refers to the thickness of the porous coating layer on one side of the porous base film. Optionally, the thickness of the porous coating layer can be 0.5 μm to 4 μm, 0.5 μm to 3 μm, 0.5 μm to 2 μm, 0.8 μm to 4 μm, 0.8 μm to 3 μm, 0.8 μm to 2 μm.

[0219] In some embodiments, the porous base film can include a film or nonwoven web selected from any one or at least two of polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyether sulfone, polyphenylene ether, cyclic olefin copolymer, polyphenylene sulfide, and polyvinyl naphthalene.

[0220] The porous base film can be a single-layer film or a multi-layer composite film. When the porous base film is a multi-layer composite film, the materials of the layers can be the same or different.

[0221] In some embodiments, the porous base film can have a thickness of 4 μm to 12 μm, and optionally 4 μm to 9 μm.

[0222] In some embodiments, the porous base film can have a porosity of 25% to 60%, and optionally 28% to 50%.

[0223] In some embodiments, the separator film can have a thickness of 5 μm to 14 μm, and optionally 5 μm to 12 μm, 6 μm to 12 μm. This is advantageous for improving the energy density of the secondary battery cell.

[0224] Dv50 represents the particle size corresponding to the cumulative volume distribution percentage of 50%, which can be tested by a laser particle size analyzer according to GB / T 19077-2016. During the test, a clean small beaker is taken, 1 g of the sample to be tested is added, 20 ml of deionized water is added, and ultrasonic treatment is performed at 53 KHz / 120 W for 5 min to ensure that the sample is completely dispersed. After the light path system is cleaned, the background is automatically tested. The sample to be tested is stirred to make it uniformly dispersed, and then placed in the sample cell according to the requirements, and the particle size is measured. The testing instrument can be a MasterSizer 3000 laser particle size analyzer.

[0225] Glass transition temperature T of the organic particles g The test can be performed as follows: an appropriate amount of sample (for example, 5 mg-15 mg) is placed in a differential scanning calorimeter (DSC) crucible, shaken to be flat, and covered with a crucible cover; parameter setting: nitrogen atmosphere, purging gas 60 mL / min, protective gas 20 mL / min; program setting: temperature rise from 25℃ to 200℃ at a rate of 10℃ / min, holding for 5 min to eliminate thermal history, then temperature drop from 200℃ to -40℃ at a rate of 10℃ / min, and then temperature rise from -40℃ to 300℃ at a rate of 10℃ / min. The glass transition temperature T of the organic particles is obtained from the DSC curve. g , or whether the organic particles have a glass transition temperature T below 300℃. g .

[0226] Glass transition temperature T g , which shows a step change on the DSC curve.

[0227] The organic particles have no glass transition temperature T below 300℃. g , which means that the DSC curve of the organic particles has no step change below 300℃.

[0228] The melting point can be tested as follows: an appropriate amount of sample (for example, 5 mg-15 mg) is placed in a differential scanning calorimeter (DSC) crucible, shaken to be flat, and covered with a crucible cover; parameter setting: nitrogen atmosphere, purging gas 60 mL / min, protective gas 20 mL / min; program setting: temperature rise from 25℃ to 200℃ at a rate of 10℃ / min, holding for 5 min to eliminate thermal history, then temperature drop from 200℃ to -40℃ at a rate of 10℃ / min, and then temperature rise from -40℃ to 300℃ at a rate of 10℃ / min. Whether the organic particles have a melting point below 300℃ is determined by the DSC curve. The organic particles have no melting point, which means that the DSC curve of the organic particles has no melting peak.

[0229] Onset temperature of thermal weight loss T 3dThe initial thermal weight loss temperature T of the organic particles refers to the temperature corresponding to a 3% loss in the mass of the sample relative to the initial mass in the thermal gravimetric analysis. The initial thermal weight loss temperature T of the organic particles 3d The test can be carried out as follows: an appropriate amount of sample (for example, 5 mg-15 mg) is placed in an alumina crucible of a thermal gravimetric analyzer (TGA), leveled, and covered with a crucible cover; the parameters are set as follows: nitrogen atmosphere, purging gas 60 mL / min, and protective gas 20 mL / min; the temperature rising program is set as follows: temperature rising rate 10 ℃ / min, and temperature range 35 ℃-600 ℃; the temperature corresponding to a 3% loss in the mass of the sample relative to the initial mass (i.e., 97% of the initial mass) is obtained from the test curve, which is the initial thermal weight loss temperature T 3d .

[0230] The oxidation peak potential of the cyclic voltammetry curve of the organic particles can be tested as follows: the organic particles, the binder polymethyl methacrylate, and the conductive agent conductive carbon black are dissolved in water to form a slurry according to a solid content mass ratio of 64:7:29, the slurry is coated on an aluminum foil as a positive electrode, a lithium foil is used as a negative electrode, and a button cell is assembled; the button cell is subjected to cyclic voltammetry (CV) test at a scanning rate of 0.10 mV / s, a voltage range of 2.50 V-5.00 V, and 3 cycles, and the voltage corresponding to the peak point of the cyclic voltammetry curve in the first cycle is taken as the oxidation peak potential. The electrolyte salt of the electrolyte used in the test is LiPF6, and the concentration is 1 mol / L. The solvent of the electrolyte is obtained by mixing ethylene carbonate (EC) and methyl ethyl carbonate (EMC) according to a volume ratio of 3:7.

[0231] The swelling degree of the organic particles can be tested as follows: an appropriate amount of sample (for example, about 1 g) is weighed as m1, placed in a semi-permeable membrane sample bag, sealed, and the sample bag can permeate the solvent but cannot permeate the sample; the sample bag is soaked in an appropriate amount of solvent (for example, about 50 g) at 60 ℃ for 7 days, then the sample bag is taken out, the sample is taken out from the sample bag, the excess solvent is wiped off, and the mass of the sample is weighed again as m2; the swelling degree = (m2-m1) / m1×100%. The solvent is a mixed solvent obtained by mixing ethylene carbonate (EC) and methyl ethyl carbonate (EMC) according to a volume ratio of 3:7.

[0232] The dissolution rate of the organic particles can be tested according to the following method: 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, record the total mass of the sample bag m2, the sample bag is permeable to the solvent, but not permeable to the sample; immerse the sample bag in an appropriate amount of solvent (for example, about 50 g) and immerse it at 60°C for 7 days, then take out the sample bag, drain and dry, and weigh the total mass of the sample bag again m3; the dissolution rate = (m2-m3) / m1x100%. The solvent is a mixed solvent of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) mixed in a volume ratio of 3:7.

[0233] It should be noted that the porous coating parameters of the above-mentioned separation film are the porous coating parameters of one side of the porous base film. When the porous coating is arranged on both sides of the porous base film, the porous coating parameters of any one side meet the present disclosure, and it is considered to fall within the protection scope of the present disclosure.

[0234] The present disclosure also provides a preparation method of a separation film, which can prepare the separation film provided by the present disclosure.

[0235] The preparation method of the separation film comprises the following steps: providing a porous base film; providing a slurry comprising first organic particles, second organic particles and a binder; coating the slurry on at least one side of the porous base film, and drying to obtain the separation film.

[0236] In some embodiments, the slurry can further comprise polymer binder particles, and after drying of the slurry, the polymer binder particles are embedded in the first organic particles and the second organic particles and form protrusions on the surface of the porous coating.

[0237] In some embodiments, the preparation method of the separation film can comprise the steps of: coating a heat-resistant layer slurry comprising first organic particles, second organic particles and a binder on at least one side of the porous base film, and drying to form a heat-resistant layer; and coating an adhesive layer slurry comprising polymer binder particles and a binder on at least a part of the surface of the heat-resistant layer, and drying to obtain the separation film.

[0238] In some embodiments, the preparation method of the separation film can comprise the steps of: coating a heat-resistant slurry comprising first organic particles, second organic particles and a binder on one side of the porous base film, and coating an adhesive layer slurry comprising polymer binder particles and a binder on at least a part of the surface of the other side of the porous base film, and drying to obtain the separation film.

[0239] In some embodiments, the solvent of the slurry can be water, for example, deionized water.

[0240] In some embodiments, the slurry can further comprise other components, for example, it can further comprise dispersants and / or wetting agents, etc.

[0241] In some embodiments, the first organic particles are crosslinked styrene-based organic particles, and the method of providing the first organic particles can comprise the following steps: providing a pre-emulsion comprising a first monomer, a first crosslinking agent, a first emulsifier, a first initiator, water, the first monomer comprising one or more of styrene and derivatives thereof; subjecting the pre-emulsion to an emulsion polymerization reaction under conditions of heating, inert gas protection, and stirring to obtain the first organic particles.

[0242] In some embodiments, the emulsion polymerization reaction can comprise the following steps: dropping the pre-emulsion into a reactor containing water under conditions of a first temperature, inert gas protection, and stirring, and after a first time, raising the temperature to a second temperature and incubating for a second time to obtain the crosslinked styrene-based organic particles.

[0243] In some embodiments, the first temperature can be 55-70°C.

[0244] In some embodiments, the first time can be 3-6h.

[0245] In some embodiments, the second temperature can be 72-92°C, for example, can be 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, or a range consisting of any of the aforementioned values.

[0246] In some embodiments, the second time can be 1-6h, for example, can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, or a range consisting of any of the aforementioned values.

[0247] The emulsion polymerization reaction is carried out under inert gas protection. In some embodiments, the inert gas can comprise one or more of nitrogen, argon, and helium.

[0248] In some embodiments, the first monomer can comprise one or more of styrene, 1-methyl-1-phenylethylene, 4-methylphenylethylene, 2-methylphenylethylene, 2,4-dimethylphenylethylene, and 2,5-dimethylphenylethylene.

[0249] The first crosslinking agent forms crosslinked structural units of the crosslinked styrene-based organic particles after polymerization with the monomers.

[0250] In some embodiments, the first crosslinking agent can include one or more of 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, triallyl isocyanurate.

[0251] In some embodiments, the mass fraction of the first crosslinking agent can be 5%-40%, for example, can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or a range consisting of any of the above numbers, based on the total mass of the first monomer and the first crosslinking agent being 100%.

[0252] The high content of the first crosslinking agent can make the obtained crosslinked styrene-based organic particles have better heat resistance.

[0253] Alternatively, the mass fraction of the first crosslinking agent can be 7%-40%, 9%-40%, 11%-40%, 13%-40%, 15%-40%, 7%-35%, 9%-35%, 11%-35%, 13%-35%, 15%-35%, 7%-31%, 9%-31%, 11%-31%, 13%-31%, 15%-31%.

[0254] In some embodiments, the first emulsifier can include one or more of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol, polyoxyethylene ether emulsifier.

[0255] Alternatively, the polyoxyethylene ether emulsifier can include OP-type emulsifiers, such as OP-4, OP-7, OP-10, OP-15, OP-20, etc.

[0256] In some embodiments, the mass fraction of the first emulsifier can be 0.25%-5%, based on the total mass of the first monomer and the first crosslinking agent being 100%.

[0257] In some embodiments, the first initiator can include, but is not limited to, one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisdimethylaminoformamide hydrochloride, azobisdimethylaminoformazane hydrochloride, azobisdimethylaminoformazane.

[0258] In some embodiments, the second organic particles are silicon-containing organic crosslinked resin particles, and a method for providing the second organic particles can include the steps of: providing a pre-emulsion containing a second monomer, a second crosslinking agent, a second emulsifier, a second initiator, water, the second monomer including a silane coupling agent containing an alkenyl group and / or an acryloyloxy group; and performing emulsion polymerization on the pre-emulsion under conditions of heating, inert gas protection, and stirring to obtain the second organic particles.

[0259] The second monomer includes a silane coupling agent containing an alkenyl group and / or an acryloyloxy group, so that free radicals are initiated between the second monomers, crosslinking reactions occur, and the second monomers also undergo crosslinking reactions with the second crosslinking agent. Thus, the second monomer and the second crosslinking agent of the present disclosure can be used as raw materials to form silicon-containing organic crosslinked resin particles having a three-dimensional network molecular structure, which are not easily softened or deformed at high temperatures and have high heat resistance.

[0260] In some embodiments, the emulsion polymerization includes the steps of: dropping the pre-emulsion into a reactor containing water under conditions of a third temperature, inert gas protection, and stirring, and then heating to a fourth temperature for a fourth time to obtain the silicon-containing organic crosslinked resin particles.

[0261] In some embodiments, the third temperature can be 55°C-70°C.

[0262] In some embodiments, the third time can be 3h-6h.

[0263] In some embodiments, the fourth temperature can be 72°C-92°C, for example, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, or a range consisting of any of the aforementioned values.

[0264] In some embodiments, the fourth time can be 1h-5h, 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, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or a range consisting of any of the aforementioned values.

[0265] The emulsion polymerization reaction is performed under inert gas protection. In some embodiments, the inert gas can include one or more of nitrogen, argon, and helium.

[0266] In some embodiments, the method can further include a step of drying the product from the emulsion polymerization reaction, and then performing a crushing process, a wet grinding process, to obtain the second organic particles.

[0267] In other embodiments, the method can further include a step of drying the product from the emulsion polymerization reaction, and then performing a baking process under an inert gas atmosphere, and then performing a crushing process, a wet grinding process, to obtain the second organic particles. In this way, the silicon-containing organic crosslinked resin particles with better heat resistance can be obtained.

[0268] In some embodiments, the drying of the product from the emulsion polymerization reaction can include, but is not limited to, vacuum drying, spray drying, air blowing drying, microwave drying, or fluidized bed drying.

[0269] In some embodiments, the drying of the product from the emulsion polymerization reaction can be performed at a temperature of 80°C to 150°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, or a range defined by any two of the foregoing values.

[0270] In some embodiments, the drying of the product from the emulsion polymerization reaction can be performed for a time period of 2h to 12h, such as 2h, 2.4h, 2.8h, 3.2h, 3.6h, 4h, 4.4h, 4.8h, 5.2h, 5.6h, 6h, 6.4h, 6.8h, 7.2h, 7.6h, 8h, 8.4h, 8.8h, 9.2h, 9.6h, 10h, 10.4h, 10.8h, 11.2h, 11.6h, 12h, or a range defined by any two of the foregoing values.

[0271] The baking is performed under an inert gas atmosphere. In some embodiments, the inert gas can include one or more of nitrogen, argon, and helium.

[0272] In some embodiments, the baking can be performed at a temperature of 160°C to 250°C, such as 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, or a range defined by any two of the foregoing values.

[0273] In some embodiments, the time for baking can be 1h-8h, for example, can be 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, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, 6.2h, 6.4h, 6.6h, 6.8h, 7h, 7.2h, 7.4h, 7.6h, 7.8h, 8h, or a range consisting of any of the above values. Alternatively, the time for baking can be 2h-8h, 2.4h-8h, 3h-8h.

[0274] In some embodiments, the crushing process can employ an air jet mill, a vibration mill, a mechanical crusher, an ultrasonic crusher, a ball mill, etc.

[0275] In some embodiments, the wet grinding process can comprise the following steps: mixing the material after the crushing process with a solvent, a grinding medium, and an optional dispersant to obtain a mixed slurry, and then subjecting the mixed slurry to a grinding process to obtain silicon-containing organic crosslinked resin particles.

[0276] Alternatively, the solvent can comprise one or more of water, methanol, ethanol. More alternatively, the solvent can comprise water.

[0277] Alternatively, the dispersant can comprise one or more of a polyacrylic acid type dispersant, a carboxymethyl cellulose type dispersant, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone. Alternatively, the polyacrylic acid type dispersant can comprise one or more of polyacrylic acid, sodium polyacrylate, potassium polyacrylate, ammonium acrylate. Alternatively, the carboxymethyl cellulose type dispersant can comprise one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, potassium carboxymethyl cellulose.

[0278] Alternatively, the grinding medium can comprise one or more of zirconium oxide balls, aluminum oxide balls, silicon nitride balls.

[0279] Alternatively, the average particle size of the grinding medium can be 0.1mm-2mm.

[0280] Optionally, the speed of rotation of the mill can be 500 rpm - 3000 rpm, for example, it can be 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, 1900 rpm, 2000 rpm, 2100 rpm, 2200 rpm, 2300 rpm, 2400 rpm, 2500 rpm, 2600 rpm, 2700 rpm, 2800 rpm, 2900 rpm, 3000 rpm, or a range consisting of any of the aforementioned values.

[0281] In some embodiments, the second monomer can include a vinyl silane coupling agent and / or an acryloxy silane coupling agent.

[0282] Optionally, the second monomer can include one or more of gamma-methacryloxypropyl tris(trimethylsiloxy)silane, (3-acryloyloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, gamma-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-t-butoxyvinylsilane, vinyltris(beta-methoxyethoxy)silane, ethylene tris[(l-methylethenyl)oxy]silane, vinyltris-t-butylperoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, methacryloxypropyldimethylmethoxysilane, (3-acryloxy)dimethylmethoxysilane, 3-methacryloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinyldimethoxysilane, vinyldiethoxysilane, methylvinyldimethoxysilane, 3-(methacryloxy)propylmethyldiethoxysilane.

[0283] The second crosslinking agent forms, after polymerization with the monomers, a crosslinking structure unit of the silicon-containing organic crosslinking resin particles.

[0284] In some embodiments, the second crosslinking agent can be a multifunctional crosslinking agent.

[0285] Optionally, the second crosslinking agent can include divinylbenzene.

[0286] Optionally, the second crosslinking agent can include one or more of divinyl benzene and 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, tripropyleneglycol diacrylate, 2,2,4-trimethylhexanedioic acid bis[2-ethylaziridine], 1,1-nonanedioic acid bis[2-methylaziridine], 1,1-(1,3-phenylenedicarbonyl)bis[2-methylaziridine], trimethylolpropane tris(2-methyl-1-aziridinyl propionate), trimethylolpropane-tris[3-(2-methylaziridinyl)propionate], pentaerythritol tri(3-aziridinyl)propionate.

[0287] In some embodiments, the mass fraction of the second crosslinking agent can be 1.5%-18%, for example, can be 1.5%, 3%, 4%, 5%, 6%, 7%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 17%, 18%, or a range consisting of any of the aforementioned values, based on the total mass of the second monomer and the second crosslinking agent being 100%.

[0288] The mass fraction of the second crosslinking agent in the above range can result in a silicon-containing organic crosslinked resin particle with good heat resistance.

[0289] Optionally, the mass fraction of the second crosslinking agent can be 4%-18%, 6%-18%, 8%-18%, 4%-16%, 6%-16%, 8%-16%, 4%-15%, 6%-15%, 8%-15%.

[0290] In some embodiments, the second emulsifier can include, but is not limited to, one or more of alkyl sulfate salts, alkyl sulfonate salts, Tween emulsifiers, fatty alcohol polyoxyethylene ethers, fatty alcohol polyoxypropylene ethers, ceteareth, oleyl ether. Optionally, the second emulsifier includes one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, Tween 20, Tween 40, laureth-7, laureth-9, laureth-10, oleyl ether-10.

[0291] In some embodiments, the second initiator can include, but is not limited to, one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyronitrile, azobisdimethylamino-2-propanimidate hydrochloride, azobisdimethylamino-2-imidazoline hydrochloride, azobisdimethylamino-2-propaneimidate hydrochloride.

[0292] In some embodiments, the mass fraction of the second initiator can be 0.15%-2.5%, for example, can be 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 1.9%, 2.1%, 2.3%, 2.5%, or a range consisting of any of the above values, based on 100% of the total mass of the second monomer and the second crosslinking agent.

[0293] In some embodiments, the pre-emulsion can further include a pH adjusting agent. Optionally, the pH adjusting agent can include, but is not limited to, one or more of sodium bicarbonate, sodium hydroxide, ammonia, etc.

[0294] In some embodiments, the second organic particles are phenolic resin-based organic particles, and the method of providing the second organic particles can include the following steps: providing a resol phenolic resin-based material; curing the resol phenolic resin-based material at a fifth temperature under a first atmosphere for a fifth time, and then curing at a sixth temperature under a second atmosphere for a sixth time, and then crushing and wet sanding to obtain the second organic particles, the fifth temperature being 90-180°C, and the sixth temperature being 190-290°C.

[0295] The fifth temperature can be 90-180°C, for example, can be 90°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 180°C, or a range consisting of any of the above values.

[0296] The fifth temperature in the above range can make the curing of the resol phenolic resin-based material in the fifth stage more uniform and sufficient, so that the phenolic resin-based organic particles with good heat resistance can be obtained.

[0297] Optionally, the fifth temperature can be 90-180°C, 100-180°C, 110-180°C, 100-165°C, 110-165°C.

[0298] The fifth temperature in the above range can make the curing of the resol phenolic resin-based material in the fifth stage more uniform and sufficient, so that the phenolic resin-based organic particles with good heat resistance can be obtained.

[0299] The sixth temperature can be in the range of 190°C to 290°C, for example, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, or a range formed by any two of the above values.

[0300] The sixth temperature can be in the above range, which can make the phenolic resin-based organic particles more fully cured, and obtain phenolic resin-based organic particles with good heat resistance.

[0301] Alternatively, the sixth temperature can be in the range of 200°C to 285°C, 200°C to 280°C.

[0302] The sixth temperature can be in the above range, which can obtain phenolic resin-based organic particles with better heat resistance.

[0303] In some embodiments, the fifth time can be in the range of 1h to 5h, 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, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or a range formed by any two of the above values.

[0304] The fifth time can be in the above range, which can make the resol resin-based material more uniformly and fully cured in the fifth stage, and thus obtain phenolic resin-based organic particles with better heat resistance.

[0305] In some embodiments, the sixth time can be in the range of 1h to 6h, 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, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, or a range formed by any two of the above values.

[0306] The sixth time can be in the above range, which can make the phenolic resin-based organic particles more fully cured and have better heat resistance.

[0307] In some embodiments, the first atmosphere can be an inert gas atmosphere or an oxygen-containing atmosphere. The oxygen-containing atmosphere can include oxygen and an inert gas. Alternatively, the volume fraction of oxygen in the oxygen-containing atmosphere can be in the range of 5% to 50%. Alternatively, the inert gas can include, but is not limited to, one or more of nitrogen, argon, and helium.

[0308] Optionally, the first atmosphere is an oxygen-containing atmosphere, and the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More optionally, the first atmosphere can be an air atmosphere.

[0309] In some embodiments, the second atmosphere can be an inert gas atmosphere or an oxygen-containing atmosphere. The oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5%-50%. Optionally, the inert gas can include, but is not limited to, one or more of nitrogen, argon, and helium.

[0310] Optionally, the second atmosphere is an oxygen-containing atmosphere, and the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More optionally, the second atmosphere can be an air atmosphere.

[0311] The resol resin material can be commercially available or synthesized according to methods known in the art. In some embodiments, the method for preparing the resol resin material includes the following steps: reacting a phenolic compound and an aldehyde compound under catalysis of an alkaline substance to obtain the resol resin material.

[0312] Optionally, the alkaline substance can include one or more of ammonia, NaOH, and Na2CO3.

[0313] Optionally, the phenolic compound can include one or more of phenol, p-dihydroxybenzene, m-dihydroxybenzene, o-dihydroxybenzene, cresol, and cardanol.

[0314] Optionally, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propyl aldehyde, n-butyl aldehyde, glyoxal, and furfural.

[0315] In some embodiments, the second organic particles are polymer particles containing triazine ring structural units, and the method for providing the second organic particles includes the following steps: providing a precursor containing a triazine ring structure; performing heat curing on the precursor containing the triazine ring structure under an oxygen-containing atmosphere, and then performing crushing and wet grinding to obtain the second organic particles, and the heat curing temperature is 180°C-290°C. After the heat curing of the precursor containing the triazine ring structure, a bridging structure is formed between the triazine ring structural units.

[0316] The heat curing temperature is 180°C-290°C, for example, can be 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, or a range consisting of any of the above values. When the heat curing temperature is within the above range, the polymer particles containing triazine ring structural units with good heat resistance can be obtained.

[0317] Optionally, the temperature for heat curing can be 200-285°C, 205-285°C, 215-285°C, 225-285°C.

[0318] In some embodiments, the time for heat curing can be 1-8h, 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, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, 6.2h, 6.4h, 6.6h, 6.8h, 7h, 7.2h, 7.4h, 7.6h, 7.8h, 8h, or a range consisting of any of the aforementioned values. The time for heat curing within the aforementioned range is beneficial for the precursor containing triazine ring structure to form polymer particles containing triazine ring structure units with better heat resistance.

[0319] Optionally, the time for heat curing can be 2-7h, 2.4-7h, 2.8-7h, 2-6.6h, 2.4-6.6h, 2.8-6.6h.

[0320] In some embodiments, the oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the inert gas can include, but is not limited to, one or more of nitrogen, argon, helium. In some embodiments, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5-50%. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 10-30%. More optionally, the oxygen-containing atmosphere can be an air atmosphere.

[0321] In some embodiments, the precursor containing triazine ring structure can include at least one of melamine formaldehyde resin, etherified melamine formaldehyde resin, a mixture of etherified melamine formaldehyde resin and at least one of polyol, polycarboxylic acid, polyamide.

[0322] In some embodiments, the precursor containing a triazine ring structure can include a melamine-formaldehyde resin, which can be obtained by reacting an aldehyde compound with an amine-substituted triazine compound, which can include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 1.75: 1-3: 1, such as 1.75: 1, 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 a range defined by any of the foregoing. More optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 2: 1-3: 1, 2.1: 1-3: 1, 2.2: 1-3: 1, 2.3: 1-3: 1, 2.4: 1-3: 1.

[0323] In some embodiments, the precursor containing a triazine ring structure can include an etherified melamine-formaldehyde resin, which can be obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound, which can include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 4: 1-7: 1, such as 4: 1, 4.5: 1, 5: 1, 5.5: 1, 6: 1, 6.5: 1, 7: 1, or a range defined by any of the foregoing. More optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 5: 1-7: 1, 5.5: 1-7: 1, 6: 1-7: 1, 6.5: 1-7: 1.

[0324] In some embodiments, the precursor containing a triazine ring structure includes a mixture of an etherified melamine-formaldehyde resin and a polyol, and the molar ratio of the etherified melamine-formaldehyde resin to the polyol can be 1:2-1:6.

[0325] In some embodiments, the precursor containing a triazine ring structure includes a mixture of an etherified melamine-formaldehyde resin and a polycarboxylic acid, and the molar ratio of the etherified melamine-formaldehyde resin to the polycarboxylic acid can be 1:2-1:6.

[0326] In some embodiments, the precursor containing a triazine ring structure includes a mixture of an etherified melamine-formaldehyde resin and a polyamide, and the molar ratio of the etherified melamine-formaldehyde resin to the polyamide can be 1:2-1:6.

[0327] In some embodiments, the alcohol compound forming the etherified melamine-formaldehyde resin can include one or more of methanol, ethanol, and butanol.

[0328] In some embodiments, the aldehyde compound that forms the melamine formaldehyde resin and the etherified melamine formaldehyde resin can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0329] In some embodiments, the amine-substituted triazine compound that forms the melamine formaldehyde resin and the etherified melamine formaldehyde resin can include one or more of the following compounds of general formula, R1, R2are each independently selected from any one of H, -NH2, C1-C8 alkyl, R3is selected from any one of H, -NH2, -NHR4, C1-C8 alkyl, C2-C8 alkenyl, phenyl, C7-C12 alkylphenyl, C7-C12 phenylalkyl, C5-C8 cycloalkyl, R4is selected from any one of -NH2, C1-C8 alkyl. Alternatively, R3is selected from -NH2or -NHR4.

[0330] Alternatively, the amine-substituted triazine compound can include one or more of melamine, benzoguanamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazinotriazine, 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-vinyl-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-triazin-2-yl)methanol, 2-chloro-4,6-diamino-1,3,5-triazine.

[0331] More alternatively, the amine-substituted triazine compound can include one or more of melamine, benzoguanamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazinotriazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine.

[0332] The etherified melamine formaldehyde resin can include one or more of partially etherified melamine formaldehyde resin, fully etherified melamine formaldehyde resin. Alternatively, the etherified melamine formaldehyde resin can include fully etherified melamine formaldehyde resin.

[0333] In some embodiments, the etherified melamine formaldehyde resin can include methyl etherified melamine formaldehyde resin, ethyl etherified melamine formaldehyde resin, butyl etherified melamine formaldehyde resin, methyl-butyl mixed etherified melamine formaldehyde resin.

[0334] Alternatively, the etherified melamine formaldehyde resin can include one or more of methyl etherified melamine formaldehyde resin, butyl etherified melamine formaldehyde resin, methyl etherified benzoguanamine formaldehyde resin, butyl etherified benzoguanamine formaldehyde resin.

[0335] The embodiments of the present disclosure also provide a secondary battery cell. The secondary battery cell includes the separator film provided by the present disclosure. Thus, the secondary battery cell can have both high energy density and high reliability.

[0336] The secondary battery cell also includes a positive electrode sheet, a negative electrode sheet, and an electrolyte, and the separator film is disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the separator film, and the negative electrode sheet can form an electrode assembly through a rolling process and / or a stacking process.

[0337] The secondary battery cell provided by the present disclosure can include, but is not limited to, a lithium battery cell, a sodium battery cell, etc. The composition of the positive electrode sheet, the negative electrode sheet, and the electrolyte can vary depending on the type of the secondary battery cell.

[0338] [Positive electrode sheet]

[0339] In some embodiments, the positive electrode sheet can include a positive current collector and a positive film layer disposed on at least one surface of the positive current collector and including a positive active material. For example, the positive current collector has two surfaces opposite in the thickness direction of the positive current collector, and the positive film layer is disposed on any one or both of the two opposite surfaces of the positive current collector.

[0340] LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi0.8Co0.2O2, LiNi0.8Co0.1Mn0.1O2, LiNi0.5Co0.2Mn0.3O2, LiNi0.5Mn1.5O2, LiNi0.5Co0.2Mn0.3O2, LiNi0.4Co0.3Mn0.3O2, LiNi0.4Co0.3Al0.3O2, LiFePO4, LiMnPO4, and modified compounds of each of the foregoing, and the like. In some embodiments, to further enhance the energy density of the secondary battery cell, the positive active material can include one or more of lithium transition metal oxides of the general formula Li a Ni b Co c M d O e A f 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.

[0341] LiCoO2, LiNiO2, LiMnO2, LiMn2O4, 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 O2, LiFePO4, LiMnPO4, and modified compounds of each of the foregoing, and the like.

[0342] The secondary battery cell will be accompanied by Li deintercalation and consumption during charging and discharging, and the molar content of Li is different when the secondary battery cell is discharged to different states. In the enumeration of the positive electrode active material in the present disclosure, the molar content of Li is the initial state of the material, i.e. the state before feeding, and the positive electrode active material is applied to the secondary battery cell. After charging and discharging cycle, the molar content of Li will change. In the enumeration of the positive electrode active material in the present disclosure, the molar content of O is only the theoretical state value, and the lattice oxygen release will cause the molar content of O to change, and the actual molar content of O will also appear to float.

[0343] Taking a sodium battery cell as an example, the positive electrode active material can include but is not limited to one or more of sodium-containing transition metal oxides, polyanion materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), prussian blue type materials. As an example, the positive electrode active material can include but is not limited to one or more of NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, 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 type materials, and materials of the general formula X p M’ q (PO4) r O x Y 3-x . In the general formula X p M’ q (PO4) r O x Y 3-x , 0 < p < 4, 0 < q < 2, 1 < r < 3, 0 < x < 2, X includes but is not limited to one or more of H + , Li + , Na + , K + and NH4 + , M' is a transition metal cation, which can optionally include but is not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, which can optionally be one or more of F, Cl and Br.

[0344] The modified compounds of the positive electrode active materials of the above lithium battery cells and sodium battery cells can be doping modification and / or surface coating modification of the positive electrode active materials.

[0345] In some embodiments, the positive electrode film layer can further include a positive electrode conductive agent. As an example, the positive electrode conductive agent can include, but is not limited to, one or more of super-P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0346] In some embodiments, the positive electrode film layer can further include a positive electrode binder. As an example, the positive electrode binder can include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylic resin.

[0347] In some embodiments, the positive electrode current collector can employ a metal foil or a composite current collector. As an example of the metal foil, an aluminum foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0348] The positive electrode film layer is generally formed by coating a positive electrode slurry on a positive electrode current collector, drying, and cold-pressing. The positive electrode slurry is generally formed by dispersing and uniformly stirring a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and any other components in a solvent. The solvent can be N-methyl pyrrolidone (NMP), but is not limited thereto.

[0349] [Negative electrode tab]

[0350] In some embodiments, the negative electrode tab can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector and including a negative electrode active material. For example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0351] The negative electrode active material can employ a material known in the art that can be used for a secondary battery cell. As an example, the negative electrode active material can include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, a silicon-based material, a tin-based material, and lithium titanate. The silicon-based material can include, but is not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and a silicon alloy material. The tin-based material can include, but is not limited to, one or more of elemental tin, tin oxide, and a tin alloy material.

[0352] In some embodiments, the negative electrode film layer can further include a negative electrode conductive agent. As an example, the negative electrode conductive agent can include, but is not limited to, one or more of super P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0353] In some embodiments, the negative electrode film layer can further include a negative electrode binder. As an example, the negative electrode binder can include, but is not limited to, one or more of styrene butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethylacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0354] In some embodiments, the negative electrode film layer can further include other auxiliary agents. As an example, the other auxiliary agents can include thickening agents, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, and the like.

[0355] In some embodiments, the negative electrode current collector can be a metal foil or a composite current collector. As an example of the metal foil, a copper foil can be used. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0356] The negative electrode film layer is typically formed by coating a negative electrode slurry on a negative electrode current collector, drying, and cold pressing. The negative electrode slurry is typically formed by dispersing and uniformly stirring a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and other optional auxiliary agents in a solvent. The solvent can be N-methyl pyrrolidone (NMP) or deionized water, but is not limited thereto.

[0357] The negative electrode tab does not exclude other additional functional layers in addition to the negative electrode film layer. For example, in some embodiments, the negative electrode tab further includes a conductive primer layer (e.g., composed of a conductive agent and a binder) interposed between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector.

[0358] In some embodiments, the negative electrode tab can use a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, or the like. When the foamed metal is used as the negative electrode tab, the surface of the foamed metal can not be provided with a negative electrode active material, and of course, can be provided with a negative electrode active material.

[0359] [Electrolyte]

[0360] The electrolyte serves to conduct ions between the positive electrode and the negative electrode.

[0361] In some embodiments, the electrolyte employs an electrolyte solution that includes an electrolyte salt and an organic solvent.

[0362] Taking a lithium battery cell as an example, the electrolyte salt can include, but is not limited to, one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium bisoxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0363] Taking a sodium battery cell as an example, the electrolyte salt can include, but is not limited to, one or more of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bisfluorosulfonylimide (NaFSI), sodium bis-trifluoromethanesulfonylimide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium bisoxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0364] In some embodiments, the organic solvent can include, but is not limited to, one or more of 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), butylene 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, crown ether.

[0365] In some embodiments, the electrolyte can further include an additive. For example, the additive can include a negative electrode film-forming additive, a positive electrode film-forming additive, and / or an additive capable of improving certain properties of the secondary battery cell, such as an additive capable of improving overcharge performance, an additive capable of improving high-temperature performance, an additive capable of improving low-temperature performance, and / or the like.

[0366] Optionally, the additive can include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propane sultone (PS), and / or vinyl sulfate (DTD).

[0367] Methods of making secondary battery cells are known. In some embodiments, a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte can be assembled to form a secondary battery cell. As an example, a positive electrode sheet, a separator, and a negative electrode sheet can be formed into an electrode assembly via a winding process and / or a stacking process, the electrode assembly can be placed in an outer package, the electrolyte described above can be injected after drying, and the secondary battery cell can be obtained after processes such as standing and formation.

[0368] Embodiments

[0369] The following examples further illustrate the present disclosure and are not intended to limit the scope of the present disclosure, as various modifications and changes can be made thereto by those skilled in the art without departing from the spirit and scope of the present disclosure. Unless otherwise stated, all proportions, percentages, and ratios reported in the following examples are by mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used as received without further purification, and all instruments used in the examples are commercially available.

[0370] Example 1

[0371] Preparation of the separator

[0372] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 80 mg of sodium persulfate, 20 ml of deionized water, 34 g of styrene, and 6 g of divinylbenzene. 140 g of deionized water and 15 mg of sodium polyacrylate were added to a reactor, which was heated to 70°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was increased to 85°C for 1.5 h of maturation reaction to obtain a first organic particle emulsion. The first organic particles were crosslinked styrene-based organic particles.

[0373] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 52 g of gamma-methacryloxypropyl triisopropoxy silane, 3 g of 3-methacryloxypropyl triethoxysilane and 5 g of divinyl benzene. A reactor was taken, 210 g of deionized water was added, and the temperature was raised to 70°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 84°C for 1.5 h of curing reaction to obtain a second organic particle emulsion. The second organic particle was a silicon-containing organic crosslinked resin particle.

[0374] The first organic particle emulsion, the second organic particle emulsion, the binder polymethyl methacrylate and the dispersant sodium carboxymethyl cellulose were added to the solvent deionized water, and stirred uniformly to obtain a heat-resistant layer slurry. The solid mass ratio of the organic particles (total solid mass of the first organic particle and the second organic particle), the dispersant sodium carboxymethyl cellulose and the binder polymethyl methacrylate in the heat-resistant layer slurry was 90:2:8. In the organic particles, the mass ratio of the crosslinked styrene organic particles to the silicon-containing organic crosslinked resin particles was 20:80.

[0375] A commercially available polyvinylidene fluoride particle, a binder polymethyl methacrylate, a dispersant sodium carboxymethyl cellulose and an ether-based surfactant were stirred uniformly in deionized water at a solid mass ratio of 87:8:3:2 to obtain an adhesive layer slurry.

[0376] A commercially available polyethylene film with a thickness of 7 μm was used as a porous base film. The heat-resistant layer slurry was coated on both surfaces of the porous base film by micro-gravure method, and after drying, the adhesive layer slurry was sprayed on the heat-resistant layer. After drying and slitting, an isolation film was obtained.

[0377] Preparation of a secondary battery cell

[0378] A positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O2, a positive electrode binder polyvinylidene fluoride (PVDF) were added to N-methyl pyrrolidone (NMP) at a mass ratio of 97:2:1, and after being fully stirred and mixed uniformly, a positive electrode slurry was prepared. The positive electrode slurry was uniformly coated on a positive electrode current collector aluminum foil, and then after drying, cold pressing and slitting, a positive electrode sheet was obtained.

[0379] A negative electrode active material artificial graphite, a negative electrode conductive agent acetylene black, a negative electrode binder styrene butadiene rubber (SBR) and a thickening agent sodium carboxymethyl cellulose were added to deionized water at a mass ratio of 96.0:1.5:1.5:1, and after being fully stirred and mixed uniformly, a negative electrode slurry was prepared. The negative electrode slurry was uniformly coated on a negative electrode current collector copper foil, and then after drying, cold pressing and slitting, a negative electrode sheet was obtained.

[0380] Ethylene carbonate (EC), methyl ethyl carbonate (EMC) were mixed at a volume ratio of 3:7 to obtain a mixed solvent, and then LiPF6, vinylene carbonate (VC), and vinyl sulfate (DTD) were dissolved in the mixed solvent to obtain an electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of VC was 2%, and the mass fraction of DTD was 3%, based on the mass of the electrolyte.

[0381] The positive electrode sheet, the separator, and the negative electrode sheet were stacked in sequence and wound and hot-pressed to obtain an electrode assembly. The electrode assembly was placed in a hard-shell outer package, and the electrolyte prepared above was added. After standing and formation, a secondary battery monomer was obtained.

[0382] Example 2

[0383] The preparation of the secondary battery monomer was the same as that of Example 1, except for the following differences.

[0384] Preparation of the separator

[0385] The solid content mass ratio of the organic particles (total solid mass of the first and second organic particles) in the heat-resistant layer slurry, the dispersant sodium carboxymethyl cellulose, and the binder polymethyl methacrylate was 90:2:8. In the organic particles, the mass ratio of the cross-linked styrene-based organic particles to the silicon-containing organic cross-linked resin particles was 10:90.

[0386] Comparative Example 1

[0387] The preparation of the secondary battery monomer was the same as that of Example 1, except for the following differences.

[0388] Preparation of the separator

[0389] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, and 60 g of γ-methacryloyloxypropyl triisopropoxy silane. A reactor was charged with 210 g of deionized water, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After 4 h of reaction, the temperature was raised to 84°C for 1.5 h of curing reaction to obtain a silicon-containing organic cross-linked resin particle D1# emulsion.

[0390] The above emulsion, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate were mixed uniformly in deionized water at a certain ratio to obtain a heat-resistant layer slurry. The solid content mass ratio of the silicon-containing organic cross-linked resin particle D1#, the dispersant sodium carboxymethyl cellulose, and the binder polymethyl methacrylate in the heat-resistant layer slurry was 90:2:8.

[0391] The commercially available polyvinylidene fluoride particles, the binder polymethyl methacrylate, the dispersant sodium carboxymethyl cellulose, and the ether-based surfactant were uniformly stirred in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0392] A commercially available polyethylene film with a thickness of 7 μm was used as the porous base film. The heat-resistant layer slurry was coated on both surfaces of the porous base film by microgravure coating, and after drying, the adhesive layer slurry was sprayed on the heat-resistant layer. After drying and slitting processes, the separator film was obtained.

[0393] Performance test

[0394] (1) Heat shrinkage rate test of the separator film

[0395] The heat shrinkage rate test of the separator film can refer to GB / T 36363-2018.

[0396] The separator film was punched into a sample with a width of 50 mm and a length of 100 mm by a punch press, and 5 parallel samples were placed on an A4 paper. Then the A4 paper with the samples was placed on a corrugated paper with a thickness of 1 mm to 5 mm.

[0397] The temperature of the air-blast oven was set to 140℃. After the temperature reached the set temperature and stabilized for 60 min, the A4 paper placed on the corrugated paper was put into the air-blast oven, and the timing started. After reaching the set time (1 h in the present disclosure), the length and width of the separator film were measured, and the values were marked as a and b, respectively.

[0398] Heat shrinkage rate calculation: longitudinal (MD) heat shrinkage rate = [(100-a) / 100] x 100%, transverse (TD) heat shrinkage rate = [(50-b) / 50] x 100%, and the average value of 3 parallel samples was taken as the test result.

[0399] (2) Overcharge resistance performance test

[0400] At 25℃, the secondary battery cell was charged at 1 / 3C constant current to 4.25V, and then charged at constant voltage until the current was 0.05C. At this time, the secondary battery cell was fully charged (100% SOC), and the time h1 from the start of charging to the full charging of the secondary battery cell was recorded. The secondary battery cell was continuously charged at 1 / 3C constant current until the secondary battery cell smoked and caught fire, and the time h2 from the start of charging to the smoking and fire of the secondary battery cell was recorded. The overcharge resistance time h2-h1 of the secondary battery cell can represent the overcharge resistance performance of the secondary battery cell. The longer the overcharge resistance time, the stronger the overcharge resistance performance of the secondary battery cell.

[0401] Table 1

[0402] From the test results, the isolation film of the present disclosure has good heat resistance, and when applied to a secondary battery cell, can simultaneously improve the overcharge resistance time of the secondary battery cell, the overcharge resistance time of the secondary battery cell is long, and the risk of thermal runaway of the secondary battery cell is low.

[0403] It should be noted that the present disclosure is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect within the scope of the technical solutions of the present disclosure are all included in the technical scope of the present disclosure. In addition, within the scope of the main idea of the present disclosure, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present disclosure.

Claims

1. An isolation membrane comprising a porous base film and a porous coating layer on at least one side of the porous base film, wherein, the porous coating layer comprises organic particles, the organic particles comprising first organic particles and second organic particles; The first organic particles and the second organic particles each have a glass transition temperature T g , and the glass transition temperature T g of the first organic particles is different from the glass transition temperature T g of the second organic particles; or, The first organic particles have a glass transition temperature T g , and the second organic particles have no glass transition temperature T g below 300°C.

2. The isolation membrane according to claim 1, wherein, the first organic particles comprise at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a crosslinked polymer; and / or, the second organic particles comprise at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a crosslinked polymer.

3. The separator film according to any one of claims 1-2, wherein, the first organic particles and the second organic particles are different in species.

4. The separator film according to any one of claims 1 to 3, wherein The first organic particles have a glass transition temperature Tg g at 165 °C, optionally 110-165 °C.

5. The separator film according to any one of claims 1 to 4, wherein the first organic particles comprise one or more of crosslinked styrene-based organic particles, polycarbonate-based organic particles, polymethacrylate methyl ester-based organic particles, polyformaldehyde-based organic particles, polyamide-based organic particles, styrene-acrylonitrile copolymers, polyphenylene sulfide-based organic particles, polyether ether ketone-based organic particles.

6. The separator film according to any one of claims 1 to 5, wherein the first organic particles comprise crosslinked styrene-based organic particles, the crosslinked styrene-based organic particles comprising styrene or styrene derivative structural units and crosslinking structural units; optionally, the styrene or styrene derivative structural units comprise one or more of styrene structural units, 1-methyl-1-styrene structural units, 4-methylstyrene structural units, 2-methylstyrene structural units, 2,4-dimethylstyrene structural units, 2,5-dimethylstyrene structural units; optionally, the crosslinking structural units comprise one or more of divinylbenzene structural units, ethylene glycol dimethacrylate structural units, pentaerythritol tetraacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, tripropylene glycol diacrylate structural units, N,N-methylenebisacrylamide structural units, N,N'-vinylbisacrylamide structural units, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural units, trisallyl isocyanurate structural units.

7. The separator film according to any one of claims 1 to 6, wherein the first organic particles comprise crosslinked styrene-based organic particles, the crosslinked styrene-based organic particles satisfying at least one of the following conditions (1) to (5): (1) the crosslinked styrene-based organic particles have no melting point; (2) the crosslinked styrenic organic particles have an onset thermal weight loss temperature T 3d of 335 °C - 388 °C; (3) a cyclic voltammogram of the crosslinked styrene-based organic particles for a first cycle has no oxidation peak in a voltage range of 2.5 V to 4.4 V; (4) a swelling degree of the crosslinked styrene-based organic particles immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate at a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%; (5) an elution rate of the crosslinked styrene-based organic particles immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate at a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

8. The separator film according to any one of claims 1 to 7, wherein said second organic particles have a glass transition temperature T g , and the glass transition temperature T g of said second organic particles is greater than the glass transition temperature T g of said first organic particles.

9. The separator film according to any one of claims 1 to 8, wherein The second organic particles have a glass transition temperature Tg g of 170°C to 290°C.

10. The separator membrane according to any one of claims 8-9, wherein, The second organic particles include one or more of polyimide-based organic particles, polysulfone-based organic particles, polyethersulfone-based organic particles, polyphenylene sulfone-based organic particles, polybenzimidazole-based organic particles, polyamide-imide-based organic particles, and polyethyleneimine-based organic particles.

11. The separator membrane according to any one of claims 1 to 7, wherein, The second organic particles have no glass transition temperature Tg below 300°C g and the second organic particles include at least one of a cross-linked polymer or a thermosetting resin polymer.

12. The separator film according to claim 11, wherein The crosslinked polymer includes silicon-containing organic crosslinking resin particles; and / or The thermosetting resin polymer includes one or more of phenol resin-based organic particles, polymer particles containing a triazine ring structure unit, epoxy resin-based organic particles, unsaturated polyester resin-based organic particles, urea-formaldehyde resin-based organic particles, and furan resin-based organic particles.

13. The separator membrane of claim 12, wherein, The silicon-containing organic crosslinking resin particles contain a benzene ring structure.

14. The separator film according to claim 13, wherein The silicon-containing organic crosslinking resin particles are network structures formed with carbon-carbon bonds as a main chain, and side chains containing a siloxane structure and a benzene ring structure.

15. The separator membrane according to any one of claims 13-14, wherein, The silicon-containing organic crosslinking resin particles include a crosslinking structure unit, and the crosslinking structure unit includes a divinylbenzene structure unit.

16. The separator film according to claim 15, wherein The crosslinking structure unit further includes one or more of a diethylene glycol divinyl ether structure unit, a triethylene glycol divinyl ether structure unit, a maleic acid diallyl ester structure unit, an ethylene glycol dimethacrylate structure unit, a 1,4-butanediol diacrylate structure unit, a 1,6-hexanediol diacrylate structure unit, a 1,8-octanediol diacrylate structure unit, a trimethylolpropane triacrylate structure unit, a pentaerythritol trimethacrylate structure unit, a tetraethylene glycol dimethacrylate structure unit, a tripropylene glycol diacrylate structure unit, a 2,2,4-trimethyladipic acid bis[2-ethylaziridine] structure unit, a 1,1-sebacic acid bis[2-methylaziridine] structure unit, a 1,1-(1,3-phenylenedicarbonyl) bis[2-methylaziridine] structure unit, a trimethylolpropane tri(2-methyl-1-aziridinyl propionate) structure unit, a trimethylolpropane-tris[3-(2-methylaziridinyl) propionate] structure unit, and a pentaerythritol tri(3-aziridinyl) propionate structure unit.

17. The separator membrane according to any one of claims 12-16, wherein, The silicon-containing organic crosslinking resin particles satisfy at least one of the following conditions (1) to (5): (1) The silicon-containing organic crosslinking resin particles have no melting point; (2) the initial thermal weight loss temperature T 3d is 240°C to 330°C; (3) The silicon-containing organic crosslinking resin particles have no oxidation peak in a cyclic voltammogram for the first cycle in a voltage range of 2.5 V to 4.4 V; (4) The silicon-containing organic crosslinking resin particles have a swelling degree of 3% or less when immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate at a volume ratio of 3:7 at 60°C for 7 days; (5) The silicon-containing organic crosslinking resin particles have a dissolution rate of 3% or less when immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate at a volume ratio of 3:7 at 60°C for 7 days.

18. The separator membrane according to any one of claims 12-17, wherein, The phenol resin-based organic particles satisfy at least one of the following conditions (1) to (6): (1) The phenol resin-based organic particles are thermosetting resol resin; (2) The phenol resin-based organic particles have no melting point; (3) the initial thermal weight loss temperature T 3d is 290°C to 350°C; (4) the phenolic resin-based organic particles do not have an oxidation peak in a voltage range of 2.5 V to 4.4 V in a first cycle of cyclic voltammetry; (5) the phenolic resin-based organic particles have a swelling degree of less than or equal to 3% 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; and (6) the phenolic resin-based organic particles have a dissolution rate of less than or equal to 3% 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.

19. The separator membrane according to any one of claims 12-18, wherein, The polymer particles containing triazine ring structural units include a bridging structure connecting the triazine ring structural units.

20. The separator membrane of claim 19, wherein, 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.

21. The separator membrane according to any one of claims 19-20, wherein, The polymer particles containing triazine ring structural units further include a substituent on the triazine ring structural units, the substituent including one or a combination of two or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, a hydroxyl group, and a halogen group.

22. The separator membrane according to any one of claims 12-21, wherein, The polymer particles containing triazine ring structural units include 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, and etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof.

23. The separator film according to claim 22, wherein The melamine formaldehyde polymers and derivatives thereof include one or more of melamine formaldehyde, benzotriazine formaldehyde, melamine-benzotriazine 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, trihydrazinotriazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde; and / or The etherified melamine formaldehyde polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzotriazine formaldehyde, and butyl etherified benzotriazine formaldehyde; and / or The etherified melamine formaldehyde-polyol polymers and derivatives thereof include 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, and butyl etherified melamine formaldehyde-polyester polyol polymer; and / or 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; and / or, 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; and / or, 24. The separator membrane according to any one of claims 12-23, wherein, The polymer particles containing a triazine ring structural unit satisfy at least one of the following conditions (1) to (5): (1) The polymer particles containing a triazine ring structural unit have no melting point; (2) the initial thermal weight loss temperature T of the polymer particles containing the triazine ring structural unit is 3d 290°C to 345°C; (3) The polymer particles containing a triazine ring structural unit have no oxidation peak in a cyclic voltammogram of the first cycle in a voltage range of 2.5 V to 4.4 V; (4) The polymer particles containing a triazine ring structural unit have a swelling degree of 3% or less when immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate at a volume ratio of 3:7 at 60°C for 7 days; (5) The polymer particles containing a triazine ring structural unit have a dissolution rate of 3% or less when immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate at a volume ratio of 3:7 at 60°C for 7 days.

25. The separator membrane of any one of claims 1-24, wherein, The volume distribution particle size Dv50 of the organic particles is 80 nm-800 nm.

26. The separator membrane of any one of claims 1-25, wherein, The mass ratio of the first organic particles to the second organic particles is 1:99 to 50:50, which can be 5:95 to 25:

75.

27. The separator film according to any one of claims 1-26, wherein, the porous coating further comprises a binder; and / or, the thickness of the porous coating is 0.5 μm-5 μm.

28. A method for preparing the separator film according to any one of claims 1-27, comprising the steps of: providing a porous base film; providing a slurry comprising first organic particles, second organic particles, and a binder; and coating the slurry on at least one side of the porous base film to obtain the separator film after drying.

29. A secondary battery cell comprising a positive electrode sheet, a negative electrode sheet, and the separator film according to any one of claims 1-27, wherein the separator film is disposed between the positive electrode sheet and the negative electrode sheet.

30. A battery device comprising a plurality of the secondary battery cell according to claim 29.

31. An electric device comprising the secondary battery cell according to claim 29 or the battery device according to claim 30.

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