Isolating membrane and preparation method thereof, secondary battery monomer, battery device and power utilization device

Abstract

The invention provides an isolating membrane and a preparation method thereof, a secondary battery monomer, a battery device and a power utilization device, the isolating membrane comprises a porous base membrane and a porous coating located on at least one side of the porous base membrane, and the porous coating comprises organic particles and inorganic particles, and the mass ratio of the organic particles in the porous coating is greater than that of the inorganic particles in the porous coating. The isolating membrane is used in the secondary battery monomer, so that the secondary battery monomer has high energy density and high reliability.

Description

Technical Field

[0001] This disclosure relates to a separator membrane and its preparation method, a secondary battery cell, a battery device, and an electrical device. Background Technology

[0002] As the application range of rechargeable battery cells becomes increasingly widespread, the demands on them are also growing, with higher requirements for energy density and reliability. Therefore, how to achieve higher energy density in rechargeable battery cells while maintaining high reliability is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] This disclosure provides a separator and its preparation method, a secondary battery cell, a battery device, and an electrical device. The separator, when used in a secondary battery cell, enables the secondary battery cell to have both high energy density and high reliability.

[0004] In a first aspect, this disclosure provides a separating membrane, including a porous base membrane and a porous coating located on at least one side of the porous base membrane, wherein the porous coating includes organic particles and inorganic particles, and the mass percentage of the organic particles in the porous coating is greater than the mass percentage of the inorganic particles in the porous coating.

[0005] Organic particles have a lower density, and their mass proportion in the porous coating is greater than that of inorganic particles. This allows secondary battery cells using the separator membrane of this disclosure to have a higher energy density. By including both organic and inorganic particles in the porous coating of the separator membrane, the overall heat resistance of the porous coating can be improved, the overall thermal shrinkage of the separator membrane can be reduced, and the reliability of the secondary battery cell can be enhanced. Therefore, the separator membrane of this disclosure enables secondary battery cells to possess both high energy density and high reliability.

[0006] In some embodiments, the organic particles constitute 50%-93% by mass in the porous coating, optionally 60%-88%.

[0007] In some embodiments, the inorganic particles account for 5%-45% by mass in the porous coating, optionally 10%-30%.

[0008] When the mass content of inorganic particles in the porous coating is within the above range, the secondary monomer can possess both good heat resistance and high energy density.

[0009] In some embodiments, the cyclic voltammetry curve of the organic particles in the first cycle does not exhibit an oxidation peak in the voltage range of 2.5V to 4.4V. The absence of an oxidation peak in the cyclic voltammetry curve of the organic particles in the first cycle within a voltage window greater than or equal to 2.5V and less than 4.4V indicates that the organic particles are stable within this voltage window and do not undergo electrochemical redox reactions. This allows the secondary battery cell provided in the embodiments of this disclosure to have a high voltage plateau and high energy density.

[0010] In some embodiments, the swelling degree of the organic particles after being immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%. The low swelling degree of the organic particles in the organic solvent results in high structural stability of the secondary battery cell during long-term use, thereby improving the problem of decreased air permeability of the separator during use.

[0011] In some embodiments, the dissolution rate of the organic particles after being immersed at 60°C for 7 days in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 is less than or equal to 3%. The low dissolution rate of the organic particles in the organic solvent results in higher structural stability during long-term use of the secondary battery cell and higher chemical stability in the electrolyte, thereby enabling the secondary battery cell to have longer cycle stability.

[0012] In some embodiments, the organic particles have no melting point. The absence of a melting point indicates good heat resistance and thermal stability. By placing these organic particles on a porous base film, the porous coating remains stable when the porous base film transitions from a glassy state to a highly elastic state. The organic particles in the porous coating better generate forces to resist the shrinkage of the porous base film, thereby improving the overall thermal shrinkage of the separator and enhancing its heat resistance.

[0013] In some embodiments, the initial thermogravimetric temperature T of the organic particles 3d ≥240℃. The initial thermogravimetric temperature T of organic particles. 3d The high thermal stability indicates good thermal stability, which can better resist the thermal shrinkage of the porous base film, improve the heat resistance of the separator, and enhance the reliability of the secondary battery cell.

[0014] In some embodiments, the true density of the organic particles is 1.0 g / cm³. 3 -2.0g / cm 3 .

[0015] In some embodiments, the true density of the inorganic particles is 2.5 g / cm³. 3 -3.5g / cm 3 .

[0016] In some embodiments, the organic particles comprise at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a crosslinked polymer.

[0017] In some embodiments, the thermoplastic resin polymer includes one or more of the following: polycarbonate organic particles, polymethyl methacrylate organic particles, polyoxymethylene organic particles, polyamide organic particles, styrene-acrylonitrile copolymer, polyphenylene sulfide organic particles, polyetheretherketone organic particles, polyimide organic particles, polysulfone organic particles, polyethersulfone organic particles, polyphenylene sulfone organic particles, polybenzimidazole organic particles, polyamide-imide organic particles, and polyethyleneimine organic particles.

[0018] In some embodiments, the thermosetting resin polymer includes one or more of the following: phenolic resin organic particles, polymer particles containing triazine ring structural units, epoxy resin organic particles, unsaturated polyester resin organic particles, urea-formaldehyde resin organic particles, and furan resin organic particles.

[0019] In some embodiments, the crosslinked polymer includes one or more of crosslinked styrene organic particles and silicon-containing organic crosslinked resin particles.

[0020] In some embodiments, the organic particles include one or more of cross-linked styrene organic particles, silicon-containing organic cross-linked resin particles, phenolic resin organic particles, and polymer particles containing triazine ring structural units.

[0021] In some embodiments, the organic particles include cross-linked styrene-based organic particles, and the cross-linked styrene-based organic particles include styrene or styrene derivative structural units and cross-linked structural units.

[0022] Optionally, the styrene or styrene derivative structural unit includes one or more of the following: styrene structural unit, 1-methyl-1-styrene structural unit, 4-methylstyrene structural unit, 2-methylstyrene structural unit, 2,4-dimethylstyrene structural unit, and 2,5-dimethylstyrene structural unit.

[0023] Optionally, the crosslinking structural unit includes one or more of the following: divinylbenzene structural unit, ethylene glycol dimethacrylate structural unit, pentaerythritol tetraacrylate structural unit, 1,4-butanediol diacrylate structural unit, 1,6-hexanediol diacrylate structural unit, 1,8-octanediol diacrylate structural unit, trimethylolpropane triacrylate structural unit, pentaerythritol trimethacrylate structural unit, tetraethylene glycol dimethacrylate structural unit, tripropylene glycol diacrylate structural unit, N,N-methylenebisacrylamide structural unit, N,N'-vinylbisacrylamide structural unit, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit, and triallyl isocyanurate structural unit.

[0024] In some embodiments, the organic particles include cross-linked styrene-based organic particles, and the glass transition temperature T of the cross-linked styrene-based organic particles is... g The temperature range is 110℃-165℃. By using the cross-linked styrene organic particles of this disclosure in the separator, the cross-linked styrene organic particles can better generate forces to resist the shrinkage of the separator, thereby improving the overall thermal shrinkage of the separator, enhancing the heat resistance of the separator, and improving the reliability of the secondary battery cells.

[0025] In some embodiments, the organic particles include cross-linked styrene-based organic particles, and the initial thermogravimetric temperature T of the cross-linked styrene-based organic particles is... 3d The temperature ranges from 335℃ to 388℃.

[0026] In some embodiments, the organic particles include cross-linked styrene-based organic particles, and the volume distribution particle size Dv50 of the cross-linked styrene-based organic particles is 80 nm-300 nm. A volume distribution particle size Dv50 within this range is beneficial for the porous coating of the separator to have good heat resistance and air permeability.

[0027] In some embodiments, the organic particles include silicon-containing organic crosslinked resin particles, and the silicon-containing organic crosslinked resin particles contain a benzene ring structure.

[0028] Optionally, the silicon-containing organic crosslinked resin particles have a network structure with carbon-carbon bonds as the main chain and side chains containing silicon-oxygen structures and benzene ring structures.

[0029] In some embodiments, the organic particles comprise silicon-containing organic crosslinked resin particles, wherein the silicon-containing organic crosslinked resin particles comprise crosslinked structural units, and the crosslinked structural units comprise divinylbenzene structural units. Optionally, the crosslinked structural units further comprise diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate 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, and tripropylene glycol diacetate structural units. One or more of the following structural units: diacrylate, 2,2,4-trimethyladipyldi[2-ethylaziridinium], 1,1-azeloyldi[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0030] In some embodiments, the organic particles comprise silicon-containing organic crosslinked resin particles, and the volume distribution particle size Dv50 of the silicon-containing organic crosslinked resin particles is 80 nm-800 nm. A volume distribution particle size Dv50 within this range is beneficial for the porous coating of the separator to possess good heat resistance and air permeability.

[0031] In some embodiments, the organic particles include silicon-containing organic crosslinked resin particles, and the silicon-containing organic crosslinked resin particles have no glass transition temperature below 300°C. The fact that the silicon-containing organic crosslinked resin particles have no glass transition temperature below 300°C indicates that they have good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the porous base film, improving the heat resistance of the separator, and enhancing the reliability of the secondary battery cell.

[0032] In some embodiments, the organic particles comprise silicon-containing organic crosslinked resin particles, and the initial thermogravimetric temperature T of the silicon-containing organic crosslinked resin particles is... 3d The temperature range is 240℃-330℃.

[0033] In some embodiments, the organic particles include phenolic resin organic particles, and the phenolic resin organic particles are thermosetting propylene resins.

[0034] In some embodiments, the organic particles include phenolic resin-based organic particles, and these phenolic resin-based organic particles have no glass transition temperature below 300°C. The fact that phenolic resin-based organic particles have no glass transition temperature below 300°C indicates good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the porous base film, improving the heat resistance of the separator, and enhancing the reliability of the secondary battery cell.

[0035] In some embodiments, the organic particles include phenolic resin organic particles, and the initial thermogravimetric temperature T of the phenolic resin organic particles is... 3d The temperature range is 300℃-350℃.

[0036] In some embodiments, the organic particles include phenolic resin organic particles, and the volume distribution particle size Dv50 of the phenolic resin organic particles is 160 nm-800 nm. A volume distribution particle size Dv50 of the polymer particles in the phenolic resin organic particles within the above range is beneficial for the porous coating of the separator to have good heat resistance and air permeability.

[0037] In some embodiments, the organic particles include polymer particles containing triazine ring structural units, and the polymer particles containing triazine ring structural units include bridging structures connecting the triazine ring structural units.

[0038] In some embodiments, the bridging structure includes one or more combinations of alkylene, alkylene ether, alkylene amine, ester, and amide groups.

[0039] In some embodiments, the triazine ring structural units of the polymer particles containing triazine ring structural units further have substituents, the substituents including one or more combinations of alkyl, alkenyl, phenyl, cycloalkyl, amino, hydroxyl, and halogen.

[0040] In some embodiments, the organic particles comprise polymer particles containing triazine ring structural units, and the polymer particles containing triazine ring structural units have no glass transition temperature below 300°C. The fact that the polymer particles containing triazine ring structural units have no glass transition temperature below 300°C indicates good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the porous base film, improving the heat resistance of the separator, and enhancing the reliability of the secondary battery cell.

[0041] In some embodiments, the organic particles comprise polymer particles containing triazine ring structural units, and the initial thermogravimetric temperature T of the polymer particles containing triazine ring structural units is... 3d The temperature ranges from 290℃ to 340℃.

[0042] In some embodiments, the organic particles comprise polymer particles containing triazine ring structural units, and the volume distribution particle size Dv50 of the polymer particles containing triazine ring structural units is 160 nm-800 nm. A volume distribution particle size Dv50 of the polymer particles containing triazine ring structural units within this range is beneficial for the porous coating of the separator to have good heat resistance and air permeability.

[0043] In some embodiments, the polymer particles containing triazine ring structural units include at least one of the following: melamine aldehyde polymers and their derivatives, etherified melamine aldehyde polymers and their derivatives, etherified melamine aldehyde-polyol polymers and their derivatives, etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives, and etherified melamine aldehyde-polyamine amide polymers and their derivatives.

[0044] In some embodiments, the melamine-formaldehyde polymers and their derivatives include one or more of melamine-formaldehyde, benzyl melamine-formaldehyde, melamine-benzene melamine-formaldehyde, melamine-(2,4-diamino-1,3,5-triazine)formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine)formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine)formaldehyde, trihydrazine-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine)formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine)formaldehyde.

[0045] In some embodiments, the etherified melamine aldehyde polymers and their derivatives include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzyl melamine formaldehyde, and butyl etherified benzyl melamine formaldehyde.

[0046] In some embodiments, the etherified melamine-formaldehyde-polyol polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-ethylene glycol polymer, methyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, methyl etherified melamine-formaldehyde-1,4-butanediol polymer, methyl etherified melamine-formaldehyde-polyester polyol polymer, methyl etherified melamine-formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine-formaldehyde-ethylene glycol polymer, butyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, butyl etherified melamine-formaldehyde-1,4-butanediol polymer, and butyl etherified melamine-formaldehyde-polyester polyol polymer.

[0047] In some embodiments, the etherified melamine-formaldehyde-polycarboxylic acid polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-oxalic acid polymer, methyl etherified melamine-formaldehyde-malonic acid polymer, methyl etherified melamine-formaldehyde-succinic acid polymer, methyl etherified melamine-formaldehyde-citric acid polymer, methyl etherified melamine-formaldehyde-phthalic acid polymer, butyl etherified melamine-formaldehyde-oxalic acid polymer, butyl etherified melamine-formaldehyde-malonic acid polymer, butyl etherified melamine-formaldehyde-citric acid polymer, butyl etherified melamine-formaldehyde-terephthalic acid polymer, and butyl etherified melamine-formaldehyde-phthalic acid polymer.

[0048] In some embodiments, the etherified melamine-formaldehyde-polyamine amide polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-glyoxalamide polymer, methyl etherified melamine-formaldehyde-malonamide polymer, methyl etherified melamine-formaldehyde-isophthalimide polymer, and butyl etherified melamine-formaldehyde-glyoxalamide polymer.

[0049] In some embodiments, the volume distribution particle size Dv50 of the inorganic particles is 200nm-800nm.

[0050] In some embodiments, the inorganic particles include one or more of the following: inorganic particles having a dielectric constant of 5 or higher, inorganic particles having ion conductivity but not storing ions, or inorganic particles capable of undergoing electrochemical reactions.

[0051] In some embodiments, the porous coating further includes an adhesive.

[0052] In some embodiments, the thickness of the porous coating is 0.5 μm-5 μm.

[0053] In a second aspect, this disclosure provides a method for preparing a separator membrane, comprising the following steps: providing a porous base membrane; providing a slurry comprising organic particles, inorganic particles, and a binder; coating the slurry onto at least one side of the porous base membrane, and drying it to obtain a separator membrane.

[0054] Thirdly, this disclosure provides a secondary battery cell, which includes a positive electrode, a negative electrode, and a separator according to the first aspect of this disclosure, wherein the separator is disposed between the positive electrode and the negative electrode.

[0055] Fourthly, this disclosure provides a battery device comprising a plurality of secondary battery cells according to the third aspect of this disclosure.

[0056] Fifthly, this disclosure provides an electrical device that includes a secondary battery cell according to the third aspect of this disclosure or a battery device according to the fourth aspect. Attached Figure Description

[0057] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0058] Figure 1 A schematic diagram of a secondary battery cell provided in some embodiments of this disclosure is shown.

[0059] Figure 2 A schematic diagram of an electrical device provided in some embodiments of this disclosure is shown. Detailed Implementation

[0060] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the separator, its preparation method, secondary battery cell, battery device, and power supply device of this disclosure. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter of the claims.

[0061] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, 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 specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

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

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

[0064] Unless otherwise specified, all steps in this disclosure may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0065] Unless otherwise specified, in this disclosure, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0066] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0067] In the description of the embodiments of this disclosure, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0068] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0069] The secondary battery cell mentioned in the embodiments of this disclosure can independently perform charge and discharge functions. After discharge, it can be reactivated by charging to allow for continued use. The secondary battery cell can be cylindrical, cuboid, or other shapes, and the embodiments of this disclosure are not limited in this regard. Figure 1 The example is a cuboid-structured secondary battery cell 5.

[0070] The secondary battery cells provided in the embodiments of this disclosure may include, but are not limited to, lithium battery cells and sodium battery cells, such as lithium-ion battery cells, sodium-ion battery cells, lithium metal battery cells, sodium metal battery cells, etc.

[0071] The secondary battery cell provided in the embodiments of this disclosure includes an electrode assembly. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of this disclosure are not limited in this regard. The secondary battery cell also includes an outer packaging, which can be used to encapsulate the electrode assembly. The outer packaging can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging can also be a soft package, such as a pouch-type soft package. The material of the soft package can be plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0072] The battery apparatus mentioned in the embodiments of this disclosure may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple secondary battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0073] In some embodiments, a battery cell assembly is typically formed by arranging multiple secondary battery cells.

[0074] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple secondary battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple secondary battery cells together with cable ties.

[0075] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

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

[0077] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple secondary battery cells to the housing.

[0078] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0079] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0080] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0081] The technical solutions described in this disclosure are applicable to various electrical devices that use secondary battery cells or battery devices, such as, but not limited to, mobile devices (e.g., mobile phones, tablets, laptops, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. Secondary battery cells and battery devices are used to store or provide electrical energy.

[0082] Figure 2 This is a schematic diagram of an example electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0083] In the context of this disclosure, the "organic particles" in the porous coating of the separator primarily serve to improve heat resistance and have virtually no adhesive properties.

[0084] The separator is a crucial component supporting the electrochemical processes of charging and discharging in a secondary battery cell. Commonly used separators are often made of polyolefins; however, polyolefins have poor heat resistance and are prone to softening or melting at high temperatures, which can lead to short circuits in the secondary battery cells. To improve the heat resistance of the separator, a porous coating is typically applied. Boehmite, alumina, and other inorganic particles are commonly used heat-resistant fillers; however, these fillers have high density and a large mass for the same bulk volume, thus affecting the energy density of the secondary battery cells.

[0085] Based on this, the present disclosure provides a separator membrane for use in secondary battery cells, which enables the secondary battery cells to have both high energy density and high reliability.

[0086] The separator disclosed herein includes a porous base membrane and a porous coating located on at least one side of the porous base membrane. The porous coating includes organic particles and inorganic particles, and the mass percentage of organic particles in the porous coating is greater than the mass percentage of inorganic particles in the porous coating.

[0087] Both the porous base membrane and the porous coating have a porous structure, which gives the separator good air permeability, facilitating ion passage. Organic particles have a low density, and their mass proportion in the porous coating is greater than that of inorganic particles, thus enabling secondary battery cells using the separator of this disclosure to have higher energy density. By including both organic and inorganic particles in the porous coating of the separator, the overall heat resistance of the porous coating can be improved, the overall thermal shrinkage of the separator can be reduced, and the reliability of the secondary battery cell can be enhanced. Therefore, the separator of this disclosure enables secondary battery cells to possess both high energy density and high reliability.

[0088] In some embodiments, the true density of the organic particles may be 1.0 g / cm³. 3 -2.0g / cm 3 .

[0089] In some embodiments, the true density of the inorganic particles can be 2.5 g / cm³. 3 -3.5g / cm 3 .

[0090] In some embodiments, the mass percentage of organic particles in the porous coating can be 50%-93%, for example, it can be 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 93%, or any range of the above values.

[0091] Optionally, the organic particles may constitute 60%-88% of the mass of the porous coating.

[0092] In some embodiments, the mass percentage of inorganic particles in the porous coating can be 5%-45%, for example, it can be 5%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, 42%, 45%, or any range of the above values.

[0093] Optionally, the inorganic particles may constitute 10%-30% of the mass of the porous coating.

[0094] Inorganic particles have a higher density and therefore a larger mass for the same packing volume. When the mass content of inorganic particles in a porous coating is within the aforementioned range, the secondary monomer can possess both good heat resistance and high energy density.

[0095] In some embodiments, the cyclic voltammetry curve of the organic particles during the first cycle does not have an oxidation peak in the voltage range of 2.5V to 4.4V.

[0096] The cyclic voltammetry curve of the organic particles in the first cycle does not have an oxidation peak in a voltage window range of 2.5V or greater and less than 4.4V, indicating that the organic particles are stable in the voltage window range of 2.5V or greater and less than 4.4V and will not undergo electrochemical redox reactions. This allows the secondary battery cell provided in the embodiments of this disclosure to have a high voltage plateau and high energy density.

[0097] In some embodiments, the swelling degree of the organic particles after being immersed in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

[0098] Organic particles have low swelling in organic solvents and high structural stability during long-term use of secondary battery cells, thereby improving the problem of decreased air permeability of the separator during use.

[0099] In some embodiments, the dissolution rate of organic particles after being soaked at 60°C for 7 days in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 is less than or equal to 3%.

[0100] Organic particles have a low dissolution rate in organic solvents, resulting in high structural stability during long-term use of secondary battery cells and high chemical stability in electrolytes. This allows secondary battery cells to have longer cycle stability.

[0101] In some embodiments, the organic particles have no melting point.

[0102] The organic particles disclosed herein have no melting point, indicating good heat resistance and thermal stability. By placing these organic particles on a porous base film, the porous coating remains stable when the porous base film transitions from a glassy state to a highly elastic state. The organic particles in the porous coating can better generate forces to resist the shrinkage of the porous base film, thereby improving the overall thermal shrinkage of the separator and enhancing its heat resistance.

[0103] In some embodiments, the initial thermogravimetric temperature T of the organic particles 3d It can be greater than or equal to 240℃. The initial thermal weight loss temperature T of organic particles. 3d The high thermal stability indicates good thermal stability, which can better resist the thermal shrinkage of the porous base film, improve the heat resistance of the separator, and enhance the reliability of the secondary battery cell.

[0104] In some embodiments, the organic particles may include at least one of a thermoplastic resin polymer, a thermosetting resin polymer, or a crosslinked polymer.

[0105] In some embodiments, the thermoplastic resin polymer may include one or more of the following: polycarbonate organic particles, polymethyl methacrylate organic particles, polyoxymethylene organic particles, polyamide organic particles, styrene-acrylonitrile copolymer, polyphenylene sulfide organic particles, polyether ether ketone organic particles, polyimide organic particles, polysulfone organic particles, polyether sulfone organic particles, polyphenylene sulfone organic particles, polybenzimidazole organic particles, polyamide-imide organic particles, and polyethyleneimine organic particles.

[0106] In some embodiments, the thermosetting resin polymer may include one or more of the following: phenolic resin organic particles, polymer particles containing triazine ring structural units, epoxy resin organic particles, unsaturated polyester resin organic particles, urea-formaldehyde resin organic particles, and furan resin organic particles.

[0107] In some embodiments, the crosslinking polymer may include one or more of crosslinked styrene organic particles and silicon-containing organic crosslinked resin particles.

[0108] In some embodiments, the organic particles may include one or more of the following: cross-linked styrene organic particles, silicon-containing organic cross-linked resin particles, phenolic resin organic particles, and polymer particles containing triazine ring structural units.

[0109] The aforementioned organic particles are poorly soluble in both water and organic solvents, such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), and chloroform, at 25°C. They are also insoluble in the mobile phase used in gel permeation chromatography and cannot be used to determine the molecular weight of the organic particles.

[0110] [Cross-linked styrene organic particles]

[0111] In some embodiments, cross-linked styrene-based organic particles include styrene or styrene derivative structural units and cross-linked structural units.

[0112] Optionally, the styrene or styrene derivative structural unit may include one or more of the following: styrene structural unit, 1-methyl-1-styrene structural unit, 4-methylstyrene structural unit, 2-methylstyrene structural unit, 2,4-dimethylstyrene structural unit, and 2,5-dimethylstyrene structural unit.

[0113] Optionally, the crosslinking structural unit may include one or more of the following: divinylbenzene structural unit, ethylene glycol dimethacrylate structural unit, pentaerythritol tetraacrylate structural unit, 1,4-butanediol diacrylate structural unit, 1,6-hexanediol diacrylate structural unit, 1,8-octanediol diacrylate structural unit, trimethylolpropane triacrylate structural unit, pentaerythritol trimethacrylate structural unit, tetraethylene glycol dimethacrylate structural unit, tripropylene glycol diacrylate structural unit, N,N-methylenebisacrylamide structural unit, N,N'-vinylbisacrylamide structural unit, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit, and triallyl isocyanurate structural unit.

[0114] In some embodiments, the glass transition temperature T of cross-linked styrene organic particles g It can be set at 110℃-165℃.

[0115] Currently, the glass transition temperature Ti of non-crosslinked styrene organic particles and commercially available crosslinked styrene organic particles is... g The temperature is relatively low, typically below 100°C. The glass transition temperature T of the cross-linked styrene-based organic particles disclosed herein is... g With a temperature range of 110℃-160℃, it exhibits high thermal stability. By using the cross-linked styrene-based organic particles of this disclosure in the separator, the cross-linked styrene-based organic particles can better generate forces to resist the shrinkage of the separator, thereby improving the overall thermal shrinkage of the separator, enhancing its heat resistance, and improving the reliability of the secondary battery cells.

[0116] In some embodiments, the initial thermogravimetric temperature T of the cross-linked styrene organic particles 3d It can be between 335℃ and 388℃.

[0117] In some embodiments, the cyclic voltammetry curves of the cross-linked styrene organic particles during the first cycle do not exhibit oxidation peaks in the voltage range of 2.5V to 4.4V.

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

[0119] In some embodiments, the dissolution rate of cross-linked styrene organic particles after being soaked at 60°C for 7 days in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 is less than or equal to 3%.

[0120] In some embodiments, cross-linked styrene-based organic particles have no melting point.

[0121] In some embodiments, the volume distribution particle size Dv50 of the cross-linked styrene organic particles can be 80 nm to 300 nm.

[0122] When the volume distribution particle size Dv50 of cross-linked styrene organic particles is within the above range, it is beneficial for the porous coating of the separator to have good heat resistance and air permeability.

[0123] [Silicone-containing organic cross-linked resin particles]

[0124] In some embodiments, the silicon-containing organic crosslinked resin particles contain a benzene ring structure.

[0125] Currently, existing silicone resins are mainly obtained by hydrolyzing hydrolytic siloxanes to form prepolymers, followed by curing, which results in poor heat resistance. The silicone-containing organic crosslinked resin particles disclosed in this invention contain a benzene ring structure. The benzene ring structure is highly rigid, which gives the silicone-containing organic crosslinked resin particles better heat resistance. By using these benzene ring-containing silicone-containing organic crosslinked resin particles in the porous coating of the separator, a better force can be generated to resist the shrinkage of the porous base membrane. This improves the overall thermal shrinkage of the separator, enhances its heat resistance, and improves the reliability of the secondary battery cells.

[0126] Optionally, the silicon-containing organic crosslinked resin particles have a network structure formed with carbon-carbon bonds as the main chain, and the side chains contain silicon-oxygen structures and benzene ring structures.

[0127] In some embodiments, the silicone-containing organic crosslinked resin particles include crosslinked structural units, which may include divinylbenzene structural units.

[0128] Optionally, the crosslinking structural unit may include a divinylbenzene structural unit, as well as diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate 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, and di... The structural unit comprises one or more of the following: tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0129] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic crosslinked resin particles can be 80nm-800nm.

[0130] The volume distribution particle size Dv50 of the silicon-containing organic crosslinked resin particles is within the above range, which is beneficial for the porous coating of the separator to have good heat resistance and air permeability.

[0131] In some embodiments, the silicone-containing organic crosslinked resin particles have no glass transition temperature below 300°C.

[0132] Silicon-containing organic crosslinked resin particles have no glass transition temperature below 300℃, indicating good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0133] In some embodiments, the initial thermogravimetric temperature T of the silicon-containing organic crosslinked resin particles 3d It can be set at 240℃-330℃.

[0134] In some embodiments, the cyclic voltammetry curves of the silicon-containing organic crosslinked resin particles during the first cycle do not exhibit oxidation peaks in the voltage range of 2.5V to 4.4V.

[0135] In some embodiments, the swelling degree of the silicon-containing organic crosslinked resin particles after being soaked in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

[0136] In some embodiments, the dissolution rate of the silicon-containing organic crosslinked resin particles after being soaked in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

[0137] In some embodiments, the silicone-containing organic crosslinked resin particles have no melting point.

[0138] [Phenolic resin organic particles]

[0139] In some embodiments, the phenolic resin organic particles are thermosetting resins.

[0140] In some embodiments, the phenolic resin organic particles are thermosetting propylene resins.

[0141] In some embodiments, phenolic resin organic particles have no glass transition temperature below 300°C.

[0142] Phenolic resin organic particles have no glass transition temperature below 300℃, indicating good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0143] In some embodiments, the initial thermogravimetric temperature T of phenolic resin organic particles 3d It can be set at 300℃-350℃.

[0144] In some embodiments, the cyclic voltammetry curve of the phenolic resin organic particles in the first cycle does not have an oxidation peak in the voltage range of 2.5V to 4.4V.

[0145] In some embodiments, the swelling degree of phenolic resin organic particles after being soaked in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

[0146] In some embodiments, the dissolution rate of phenolic resin organic particles after being soaked at 60°C for 7 days in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 is less than or equal to 3%.

[0147] In some embodiments, phenolic resin organic particles have no melting point.

[0148] In some embodiments, the volume distribution particle size Dv50 of phenolic resin organic particles can be 160nm-800nm.

[0149] The volume distribution particle size Dv50 of phenolic resin organic particles within the above range is beneficial for the porous coating of the separator to have good heat resistance and air permeability.

[0150] [Polymer particles containing triazine ring structural units]

[0151] The triazine ring structure is highly rigid, which gives the polymer particles good heat resistance.

[0152] The polymer particles containing triazine ring structural units disclosed herein include bridging structures that connect the triazine ring structural units.

[0153] Polymer particles containing triazine ring structural units have multiple triazine ring structural units in their molecular structure. The bridging structure refers to the groups that connect the triazine ring structural units, and the bridging structures may be the same or different.

[0154] Optionally, the bridging structure may include one or more of the following: alkylene, alkylene ether, alkylene amine, ester group, and amide group.

[0155] Alternatively, the bridging structure may include one or more of methylene, methylene ether, and methyleneamine.

[0156] In some embodiments, the triazine ring structural units of the polymer particles containing triazine ring structural units may also have substituents, which may include one or more combinations of alkyl, alkenyl, phenyl, cycloalkyl, amino, hydroxyl, and halogen.

[0157] In some embodiments, polymer particles containing triazine ring structural units may include at least one of the following: melamine aldehyde polymers and their derivatives, etherified melamine aldehyde polymers and their derivatives, etherified melamine aldehyde-polyol polymers and their derivatives, etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives, and etherified melamine aldehyde-polyamine amide polymers and their derivatives.

[0158] In some embodiments, melamine aldehyde polymers and their derivatives may include melamine formaldehyde polymers and their derivatives.

[0159] Optionally, melamine-formaldehyde polymers and their derivatives may include one or more of the following: melamine-formaldehyde, benzyl melamine-formaldehyde, melamine-benzene melamine-formaldehyde, melamine-(2,4-diamino-1,3,5-triazine)formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine)formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine)formaldehyde, trihydrazine-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine)formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine)formaldehyde.

[0160] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include etherified melamine formaldehyde polymers and their derivatives.

[0161] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include methyl etherified melamine aldehyde polymers and their derivatives, diethyl etherified melamine aldehyde polymers and their derivatives, butyl etherified melamine aldehyde polymers and their derivatives, and methyl-butyl mixed etherified melamine aldehyde polymers and their derivatives.

[0162] Optionally, the etherified melamine-formaldehyde polymers and their derivatives may include methyl etherified melamine-formaldehyde polymers and their derivatives, diethyl etherified melamine-formaldehyde polymers and their derivatives, butyl etherified melamine-formaldehyde polymers and their derivatives, and methyl-butyl mixed etherified melamine-formaldehyde polymers and their derivatives.

[0163] Etherified melamine aldehyde polymers and their derivatives may include one or more of partially etherified melamine aldehyde polymers and their derivatives, and fully etherified melamine aldehyde polymers and their derivatives. Optionally, etherified melamine aldehyde polymers and their derivatives may include fully etherified melamine aldehyde polymers and their derivatives.

[0164] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzyl melamine formaldehyde, and butyl etherified benzyl melamine formaldehyde.

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

[0166] In some embodiments, the polyol may include one or more of diols, triols, and tetraols. Optionally, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethylbutyric acid, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyols, and polyester polyols. More preferably, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, polyvinyl alcohol, and polyester polyols.

[0167] Optionally, the polyester polyol may include one or more of the following: polyethylene adipate diol, 1,4-butanediol adipate diol, propylene adipate diol, neopentyl adipate diol, neopentyl adipate-1,6-hexanediol adipate diol, hexanediol adipate diol, polycarbonate diol, and polycaprolactone diol.

[0168] Optionally, the polyether polyol may include one or more of polyoxypropylene glycol, polyoxypropylene triol, and polytetrahydrofuran glycol.

[0169] Optionally, the molecular weight of the polyester polyol can be below 5000, and optionally below 2000.

[0170] Optionally, the molecular weight of the polyether polyol can be below 5000, and optionally below 2000.

[0171] Optionally, the molecular weight of polyvinyl alcohol can be below 5000, and optionally below 2000.

[0172] In some embodiments, the etherified melamine-formaldehyde-polyol polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-ethylene glycol polymer, methyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, methyl etherified melamine-formaldehyde-1,4-butanediol polymer, methyl etherified melamine-formaldehyde-polyester polyol polymer, methyl etherified melamine-formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine-formaldehyde-ethylene glycol polymer, butyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, butyl etherified melamine-formaldehyde-1,4-butanediol polymer, and butyl etherified melamine-formaldehyde-polyester polyol polymer.

[0173] Etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polycarboxylic acid. Optionally, the molar ratio of etherified melamine aldehyde resin to polycarboxylic acid can be 1:2 to 1:6.

[0174] In some embodiments, the polycarboxylic acid may include one or more of dicarboxylic acids, tricarboxylic acids, and tetracarboxylic acids. Optionally, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid. More preferably, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, and terephthalic acid.

[0175] In some embodiments, the etherified melamine-formaldehyde-polycarboxylic acid polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-oxalic acid polymer, methyl etherified melamine-formaldehyde-malonic acid polymer, methyl etherified melamine-formaldehyde-succinic acid polymer, methyl etherified melamine-formaldehyde-citric acid polymer, methyl etherified melamine-formaldehyde-phthalic acid polymer, butyl etherified melamine-formaldehyde-oxalic acid polymer, butyl etherified melamine-formaldehyde-malonic acid polymer, butyl etherified melamine-formaldehyde-citric acid polymer, butyl etherified melamine-formaldehyde-terephthalic acid polymer, and butyl etherified melamine-formaldehyde-phthalic acid polymer.

[0176] Etherified melamine aldehyde-polyamine amide polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polyamine amide. Optionally, the molar ratio of etherified melamine aldehyde resin to polyamine amide can be 1:2 to 1:6.

[0177] In some embodiments, the polyamide may include one or more of ethylene glycol, malonamide, succinamide, adipamide, and isophthalimide. Optionally, the polyamide may include one or more of ethylene glycol, malonamide, and isophthalimide.

[0178] In some embodiments, the etherified melamine-formaldehyde-polyamine amide polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-glyoxalamide polymer, methyl etherified melamine-formaldehyde-malonamide polymer, methyl etherified melamine-formaldehyde-isophthalimide polymer, and butyl etherified melamine-formaldehyde-glyoxalamide polymer.

[0179] In some embodiments, polymer particles containing triazine ring structural units have no glass transition temperature below 300°C.

[0180] Polymer particles containing triazine ring structural units have no glass transition temperature below 300℃, indicating good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0181] In some embodiments, the initial thermogravimetric temperature T of the polymer particles containing the triazine ring structural unit is... 3d It can be between 290℃ and 340℃.

[0182] In some embodiments, the cyclic voltammetry curves of polymer particles containing triazine ring structural units do not exhibit oxidation peaks in the voltage range of 2.5V to 4.4V during the first cycle.

[0183] In some embodiments, the swelling degree of polymer particles containing triazine ring structural units after being immersed in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%.

[0184] In some embodiments, the dissolution rate of polymer particles containing triazine ring structural units after being immersed at 60°C for 7 days in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 is less than or equal to 3%.

[0185] In some embodiments, polymer particles containing triazine ring structural units have no melting point.

[0186] In some embodiments, the volume distribution particle size Dv50 of polymer particles containing triazine ring structural units can be 160 nm-800 nm.

[0187] The volume distribution particle size Dv50 of polymer particles containing triazine ring structural units within the above range is beneficial to the porous coating of the separator having good heat resistance and air permeability.

[0188] [Inorganic particles]

[0189] In some embodiments, the volume distribution particle size Dv50 of the inorganic particles can be 200nm-800nm, and can be selected as 200nm-700nm, 200nm-600nm, 200nm-500nm, 220nm-700nm, 220nm-600nm, or 220nm-500nm.

[0190] In some embodiments, inorganic particles may include one or more of the following: inorganic particles having a dielectric constant of 5 or greater, inorganic particles having ion conductivity but not storing ions, or inorganic particles capable of undergoing electrochemical reactions.

[0191] In some embodiments, inorganic particles having a dielectric constant of 5 or higher may include boehmite, alumina, barium sulfate, magnesium oxide, magnesium hydroxide, silicon oxides, tin dioxide, titanium oxide, calcium oxide, zinc oxide, zirconium oxide, yttrium oxide, nickel oxide, hafnium dioxide, cerium oxide, zirconium titanate, barium titanate, magnesium fluoride, aluminum hydroxide, barium oxide, silicon carbide, boron carbide, aluminum nitride, silicon nitride, boron nitride, calcium fluoride, barium fluoride, magnesium aluminum silicate, lithium magnesium silicate, sodium magnesium silicate, bentonite, hydropyrite, Pb(Zr,Ti)O3 (abbreviated as PZT), Pb 1-m La m Zr 1-n Ti n O3 (abbreviated as PLZT, 0 < m < 1, 0 < n < 1), Pb (Mg3Nb) 2 / 3 The inorganic particles can be selected from one or more of PbTiO3 (PMN-PT) and their respective modified inorganic particles. Optionally, the modification of each inorganic particle can be chemical modification and / or physical modification.

[0192] In some embodiments, inorganic particles that are ion-conductive but do not store ions may include Li3PO4, lithium titanium phosphate (Li3PO4), etc. x1 Ti y1 (PO4)3, Lithium aluminum titanium phosphate (Li) x2 Al y2 Ti z1 (PO4)3、(LiAlTiP) x3 O y3 Type glass, lithium lanthanum titanate (Li) x4 La y4 TiO3, lithium germanium thiophosphate Li x5 Ge y5 P z2 S w Lithium nitride (Li) x6 N y6 SiS2 type glass Li x7 Siy7 S z3 and P2S5 type glass Li x8 P y8 S z4 One or more of the following are given: 0 < x1 < 2, 0 < y1 < 3, 0 < x2 < 2, 0 < y2 < 1, 0 < z1 < 3, 0 < x3 < 4, 0 < y3 < 13, 0 < x4 < 2, 0 < y4 < 3, 0 < x5 < 4, 0 < y5 < 1, 0 < z2 < 1, 0 < w < 5, 0 < x6 < 4, 0 < y6 < 2, 0 < x7 < 3, 0 < y7 < 2, 0 < z3 < 4, 0 < x8 < 3, 0 < y8 < 3, 0 < z4 < 7. This can improve the ion conductivity of the separator.

[0193] In some embodiments, the inorganic particles capable of undergoing electrochemical reactions may include one or more of lithium-containing transition metal oxides, lithium-containing phosphates, carbon-based materials, silicon-based materials, tin-based materials, and lithium-titanium compounds.

[0194] In some embodiments, the porous coating includes an adhesive, which may include, but is not limited to, one or more of polyacrylate adhesives, nitrile rubber adhesives, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0195] In some embodiments, the porous coating may further include a dispersant, such as one or more of alkylphenol polyoxyethylene ethers, polyacrylic acid dispersants, and cellulose dispersants, including but not limited to. As an example, the dispersant may include, but is not limited to, one or more of sodium carboxymethyl cellulose, sodium polyacrylate, and ammonium polyacrylate.

[0196] In some embodiments, the separator may also include polymer binder particles.

[0197] The "polymer binder particles" in the porous coating of the separator membrane play a role in improving the adhesion between the separator membrane and the electrode, but they have virtually no heat resistance.

[0198] In some embodiments, polymer binder particles may be embedded in organic and inorganic particles and form protrusions on the surface of the porous coating.

[0199] In other embodiments, the porous coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on the porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the heat-resistant layer on the side away from the porous base membrane. Organic particles and inorganic particles are disposed in the heat-resistant layer, and polymer binder particles are disposed in the adhesive layer.

[0200] In some other embodiments, the porous coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on one side of the porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the other side of the porous base membrane. Organic particles and inorganic particles are disposed in the heat-resistant layer, and polymer binder particles are disposed in the adhesive layer.

[0201] In some embodiments, the average particle size of the polymer binder particles can be 6 μm-18 μm.

[0202] In some embodiments, the polymer binder particles may include vinylidene fluoride polymer particles, such as polyvinylidene fluoride (PVDF) particles and / or copolymer particles of vinylidene fluoride monomer and comonomer.

[0203] Comonomers may include at least one of olefin monomers, fluorinated olefin monomers, chlorinated olefin monomers, acrylate monomers, acrylic monomers, and fluoroether monomers.

[0204] Optionally, the comonomer may include at least one of the following: trifluoroethylene, trifluorochloroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl) ether (e.g., perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether), perfluoro(1,3-m-dioxacyclopentene), and perfluoro(2,2-dimethyl-1,3-m-dioxacyclopentene).

[0205] In some embodiments, the thickness of the porous coating can be 0.5 μm-5 μm. The thickness of the porous coating refers to the thickness of the porous coating located on one side of the porous base film. Optionally, the thickness of the porous coating can be 0.5 μm-4 μm, 0.5 μm-3 μm, 0.5 μm-2 μm, 0.8 μm-4 μm, 0.8 μm-3 μm, or 0.8 μm-2 μm.

[0206] In some embodiments, the porous base membrane may comprise a membrane or nonwoven web selected from any one or at least two of the following: polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymer, polyphenylene sulfide, and polyvinylnaphthalene.

[0207] Porous base membranes can be single-layer thin films or multi-layer composite thin films. When a porous base membrane is a multi-layer composite thin film, the materials of each layer can be the same or different.

[0208] In some embodiments, the thickness of the porous base film can be 4μm-12μm, and optionally 4μm-9μm.

[0209] In some embodiments, the porosity of the porous base membrane can be 25%-60%, optionally 28%-50%.

[0210] In some embodiments, the thickness of the separator can be 5μm-14μm, optionally 5μm-12μm or 6μm-12μm. This is beneficial for improving the energy density of the secondary battery cell.

[0211] Dv50 represents the particle size corresponding to a cumulative volumetric distribution percentage of 50% for the material. It can be measured using a laser particle size analyzer, referring to GB / T19077-2016. During testing, add 1g of the sample to a clean small beaker, along with 20ml of deionized water. Sonicate at 53kHz / 120W for 5 minutes to ensure complete dispersion. Turn on the laser particle size analyzer, clean the optical path system, and automatically test the background. Stir the sonicated solution to ensure uniform dispersion, then place it in the sample cell as required and begin measuring the particle size. A MasterSizer 3000 laser particle size analyzer can be used as the testing instrument.

[0212] Glass transition temperature T of organic particles g The test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The glass transition temperature T of the organic particles is obtained from the DSC curve. g Or determine whether organic particles have a glass transition temperature T below 300℃. g .

[0213] Glass transition temperature T g It refers to the transition temperature from the glassy state to the elastic state, which shows a step-like change on the DSC curve.

[0214] Organic particles have no glass transition temperature T below 300℃ g This means that the DSC curve of organic particles does not show a step-like change in the range below 300℃.

[0215] Melting point can be tested as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of a differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The DSC curve is used to determine whether the organic particles have a melting point below 300℃. Organic particles without a melting point mean that the DSC curve of the organic particles does not show a melting peak.

[0216] Initial thermogravimetric temperature T 3d This refers to the temperature at which the sample mass loses 3% relative to its initial mass in a thermogravimetric analysis test. The initial thermogravimetric temperature T for organic particles. 3d The test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the alumina crucible of the thermogravimetric analyzer (TGA), level it, and cover the crucible with the lid; Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; Temperature rise program: heating rate 10℃ / min, temperature range 35℃-600℃; Obtain the temperature corresponding to a 3% loss of sample mass relative to the initial mass (i.e., 97% of the initial mass) from the test curve, which is the initial thermogravimetric temperature T. 3d .

[0217] The oxidation peak potential of the cyclic voltammetry curve of organic particles can be tested as follows: Organic particles, binder polymethyl methacrylate, and conductive carbon black are dissolved in water at a solid content mass ratio of 64:7:29 to prepare a slurry. The slurry is coated on aluminum foil as the positive electrode, and lithium foil is used as the negative electrode to assemble a coin cell. Cyclic voltammetry (CV) is performed on the coin cell at a scan rate of 0.10 mV / s, a voltage range of 2.50 V-5.00 V, and 3 cycles. The voltage corresponding to the peak point of the first cyclic voltammetry curve is taken as the oxidation peak potential. The electrolyte salt used in the test is LiPF6 with a concentration of 1 mol / L. The solvent of the electrolyte is obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) at a volume ratio of 3:7.

[0218] The swelling degree of organic particles can be tested as follows: Take an appropriate amount of sample (e.g., about 1g), denoted as m1, and place it in a semi-permeable membrane sample bag. Seal the bag; the sample bag should be permeable to the solvent but not to the sample. Immerse the sample bag in an appropriate amount of solvent (e.g., about 50g) at 60°C for 7 days. After immersion, remove the sample bag and then remove the sample from the bag. Wipe away excess solvent and weigh the sample again, m2. Swelling degree = (m2-m1) / m1×100%. The solvent is a mixed solvent obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7.

[0219] The dissolution rate of organic particles can be tested as follows: Take an appropriate amount of sample (e.g., about 1g), and record its mass as m1. Place it in a semi-permeable membrane sample bag, seal it, and record the total mass of the sample bag as m2. The sample bag is permeable to the solvent but not to the sample. Immerse the sample bag in an appropriate amount of solvent (e.g., about 50g) at 60°C for 7 days. After that, remove the sample bag, drain it, dry it, and weigh the total mass of the sample bag again as m3. Dissolution rate = (m2-m3) / m1 × 100%. The solvent is a mixed solvent obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7.

[0220] It should be noted that the porous coating parameters of the above-mentioned separator are all the porous coating parameters of one side of the porous base membrane. When the porous coating is disposed on both sides of the porous base membrane, if the porous coating parameters of either side meet the requirements of this disclosure, it is considered to fall within the protection scope of this disclosure.

[0221] This disclosure also provides a method for preparing a separator membrane, which can prepare the separator membrane provided in this disclosure.

[0222] The method for preparing the separator membrane includes the following steps: providing a porous base membrane; providing a slurry comprising organic particles, inorganic particles, and a binder; coating the slurry onto at least one side of the porous base membrane; and drying to obtain the separator membrane.

[0223] In some embodiments, the slurry may further include polymer binder particles, which, after drying, are embedded in organic and inorganic particles and form protrusions on the porous coating surface.

[0224] In some embodiments, the method for preparing the separator membrane may include: coating a heat-resistant layer slurry comprising organic particles, inorganic particles, and a binder onto at least one side of a porous base membrane, and drying it to form a heat-resistant layer; and coating an adhesive layer slurry comprising polymer binder particles and a binder onto at least a portion of the surface of the heat-resistant layer, and drying it to obtain the separator membrane.

[0225] In some embodiments, the method for preparing the separator membrane may include: coating a heat-resistant slurry comprising organic particles, inorganic particles, and a binder onto one side of a porous base membrane, and coating an adhesive layer slurry comprising polymer binder particles and a binder onto at least a portion of the surface of the other side of the porous base membrane, and drying the slurry to obtain the separator membrane.

[0226] In some embodiments, the solvent for the slurry may be water, such as deionized water.

[0227] In some embodiments, the slurry may also include other components, such as dispersants and / or wetting agents.

[0228] In some embodiments, the organic particles are cross-linked styrene-based organic particles. The method for preparing the organic particles may include the following steps: providing a pre-emulsion comprising a first monomer, a first cross-linking agent, a first emulsifier, a first initiator, and water, wherein the first monomer comprises one or more of styrene and its derivatives; and subjecting the pre-emulsion to emulsion polymerization under heating, inert gas protection, and stirring conditions to obtain the organic particles.

[0229] In some embodiments, the emulsion polymerization reaction may include the following steps: adding a pre-emulsion dropwise into a reactor containing water under a first temperature, an inert gas protection and stirring conditions, reacting for a first time, then heating to a second temperature to mature the reaction for a second time, to obtain cross-linked styrene-based organic particles.

[0230] In some embodiments, the first temperature can be 55°C-70°C.

[0231] In some embodiments, the first time can be 3h-6h.

[0232] In some embodiments, the second temperature can be 72℃-92℃, for example, it can be 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, or any range of the above values.

[0233] In some embodiments, the second time can be 1h-6h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h or any range of the above values.

[0234] The emulsion polymerization reaction is carried out under the protection of an inert gas. In some embodiments, the inert gas may include one or more of nitrogen, argon, and helium.

[0235] In some embodiments, the first monomer may include one or more of styrene, 1-methyl-1-styrene, 4-methylstyrene, 2-methylstyrene, 2,4-dimethylstyrene, and 2,5-dimethylstyrene.

[0236] In some embodiments, the first crosslinking agent may 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, and triallyl isocyanurate.

[0237] In some embodiments, based on the total mass of the first monomer and the first crosslinking agent being 100%, the mass fraction of the first crosslinking agent can be 5%-40%, for example, it 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 any range of the above values.

[0238] A high content of the first crosslinking agent can give the resulting crosslinked styrene-based organic particles better heat resistance.

[0239] Optionally, 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%, or 15%-31%.

[0240] In some embodiments, the first emulsifier may include one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol, and polyoxyethylene ether emulsifier.

[0241] Optionally, the polyoxyethylene ether emulsifier may include OP-type emulsifiers, such as OP-4, OP-7, OP-10, OP-15, OP-20, etc.

[0242] In some embodiments, the mass fraction of the first emulsifier may be 0.25%-5%, based on the total mass of the first monomer and the first crosslinking agent being 100%.

[0243] In some embodiments, the first initiator may be one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyramidine hydrochloride, azobisisobutyramidine hydrochloride, and azobisisopropylimidazoline.

[0244] In some embodiments, the organic particles are silicon-containing organic crosslinked resin particles. The method for preparing the organic particles may include the following steps: providing a pre-emulsion comprising a second monomer, a second crosslinking agent, a second emulsifier, a second initiator, and water, wherein the second monomer comprises a silane coupling agent containing an alkenyl group and / or an acryloyloxy group; and subjecting the pre-emulsion to an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain the organic particles.

[0245] The second monomer includes a silane coupling agent containing an alkenyl group and / or an acryloyloxy group. Therefore, free radicals can be generated between the second monomers, resulting in a cross-linking reaction. Furthermore, the second monomer can also undergo a cross-linking reaction with the second cross-linking agent. Thus, using the second monomer and the second cross-linking agent of this disclosure as raw materials, silicon-containing organic cross-linked resin particles with a three-dimensional network molecular structure can be formed. These particles are not easily softened or deformed at high temperatures and exhibit high heat resistance.

[0246] In some embodiments, the emulsion polymerization reaction includes the following steps: under a third temperature, inert gas protection and stirring conditions, the pre-emulsion is dropwise added to a reactor containing water, and after a third reaction time, the temperature is raised to a fourth temperature to mature the reaction for a fourth time to obtain silicon-containing organic crosslinked resin particles.

[0247] In some embodiments, the third temperature can be 55°C-70°C.

[0248] In some embodiments, the third time can be 3h-6h.

[0249] In some embodiments, the fourth temperature can be 72℃-92℃, for example, it can be 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, or any range of the above values.

[0250] In some embodiments, the fourth time can be 1h-5h, for example, it 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, or any range of the above values.

[0251] The emulsion polymerization reaction is carried out under the protection of an inert gas. In some embodiments, the inert gas may include one or more of nitrogen, argon, and helium.

[0252] In some embodiments, the method may further include the steps of: drying the product obtained from the emulsion polymerization reaction, and then subjecting it to a crushing process and a wet grinding process to obtain silicon-containing organic crosslinked resin particles.

[0253] In other embodiments, the method may further include the steps of: drying the product obtained from the emulsion polymerization reaction, then baking it under an inert gas atmosphere, followed by crushing and wet grinding processes to obtain silicon-containing organic crosslinked resin particles. This yields silicon-containing organic crosslinked resin particles with better heat resistance.

[0254] In some embodiments, the drying methods for the products obtained from emulsion polymerization may include, but are not limited to, vacuum drying, spray drying, forced air drying, microwave drying, or fluidized bed drying.

[0255] In some embodiments, the drying temperature of the product obtained from the emulsion polymerization reaction can be 80℃-150℃, for example, it can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, or any combination of the above values.

[0256] In some embodiments, the drying time of the product obtained from the emulsion polymerization reaction can be 2h-12h, for example, it can be 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 any range of the above values.

[0257] Baking is carried out in an inert gas atmosphere. In some embodiments, the inert gas may include one or more of nitrogen, argon, and helium.

[0258] In some embodiments, the baking temperature can be 160℃-250℃, for example, it can be 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, or any range of the above values.

[0259] In some embodiments, the baking time can be 1 hour to 8 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours, 6 hours, 6.2 hours, 6.4 hours, 6.6 hours, 6.8 hours, 7 hours, 7.2 hours, 7.4 hours, 7.6 hours, 7.8 hours, 8 hours, or any range of the above values. Optionally, the baking time can be 2 hours to 8 hours, 2.4 hours to 8 hours, or 3 hours to 8 hours.

[0260] In some embodiments, the crushing process can employ air jet mills, vibratory mills, mechanical mills, ultrasonic mills, ball mills, etc.

[0261] In some embodiments, the wet grinding process may include the following steps: mixing crushed material with solvent, grinding media and optional dispersant to obtain a mixed slurry, and then grinding the mixed slurry to obtain silicon-containing organic crosslinked resin particles.

[0262] Optionally, the solvent may include one or more of water, methanol, and ethanol. More preferably, the solvent may include water.

[0263] Optionally, the dispersant may include one or more of polyacrylic acid dispersants, carboxymethyl cellulose dispersants, polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone. Optionally, the polyacrylic acid dispersant may include one or more of polypropionic acid, sodium polyacrylate, potassium polyacrylate, and ammonium acrylate. Optionally, the carboxymethyl cellulose dispersant may include one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, and potassium carboxymethyl cellulose.

[0264] Optionally, the polishing media may include one or more of zirconia balls, alumina balls, and silicon nitride balls.

[0265] Optionally, the average particle size of the grinding media can be 0.1 mm to 2 mm.

[0266] Optionally, the grinding speed can be 500rpm-3000rpm.

[0267] In some embodiments, the second monomer may include a vinylsilane coupling agent and / or an acryloyloxysilane coupling agent.

[0268] Optionally, the second monomer may include γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-tert-butoxyvinylsilane, vinyl One or more of the following: tris(β-methoxyethoxy)silane, ethylenetris[(1-methylvinyl)oxy]silane, vinyltritert-butylperoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane.

[0269] In some embodiments, the second crosslinking agent may be a multifunctional crosslinking agent.

[0270] Optionally, the second crosslinking agent may include divinylbenzene.

[0271] Optionally, the second crosslinking agent may include divinylbenzene and one or more of the following: diethylene glycol divinyl ether, triethylene glycol divinyl ether, diallyl maleate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-nonaiyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0272] In some embodiments, based on the total mass of the second monomer and the second crosslinking agent being 100%, the mass fraction of the second crosslinking agent can be 1.5%-18%, for example, it 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 any range of the above values.

[0273] When the mass fraction of the second crosslinking agent is within the above range, silicon-containing organic crosslinked resin particles with good heat resistance can be obtained.

[0274] 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%, or 8%-15%.

[0275] In some embodiments, the second emulsifier may include, but is not limited to, one or more of alkyl sulfates, alkyl sulfonates, Tween-based emulsifiers, fatty alcohol polyoxyethylene ethers, fatty alcohol polyoxypropylene ethers, cetearyl alcohol polyethers, and oleyl alcohol polyethers. Optionally, the second emulsifier includes one or more of sodium lauryl sulfate, sodium lauryl sulfonate, Tween 20, Tween 40, lauryl ether-7, lauryl ether-9, lauryl ether-10, and oleyl alcohol polyether-10.

[0276] In some embodiments, the second initiator may be one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyronitrile, azobisisobutyramidine hydrochloride, azobisisobutyramidine imidazoline hydrochloride, and azobisisopropylimidazoline.

[0277] In some embodiments, the mass fraction of the second initiator, based on the total mass of the second monomer and the second crosslinking agent as 100%, can be 0.15%-2.5%, for example, 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 any range of the above values. Optionally, the mass fraction of the second initiator can be 0.3%-2.1%, 0.3%-1.9%, 0.3%-1.7%, 0.3%-1.5%, or 0.3%-1.3%.

[0278] In some embodiments, the preemulsion may further include a pH adjuster. Optionally, the pH adjuster may include, but is not limited to, one or more of sodium bicarbonate, sodium hydroxide, ammonia, etc.

[0279] In some embodiments, the organic particles are phenolic resin organic particles. The preparation method of the organic particles may include the following steps: providing a methyl phenolic resin material; curing the methyl phenolic resin material at a fifth temperature and a first atmosphere for a fifth time, then curing it at a sixth temperature and a second atmosphere for a sixth time, and then crushing and wet milling to obtain organic particles, wherein the fifth temperature is 90℃-180℃ and the sixth temperature is 190℃-290℃.

[0280] The fifth temperature is 90℃-180℃, for example, it can be 90℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, 180℃, or any range of the above values.

[0281] The fifth temperature, within the above range, allows for more uniform and complete curing of the first-stage phenolic resin material in the fifth stage, thereby yielding phenolic resin organic particles with good heat resistance.

[0282] Optionally, the fifth temperature is 90℃-180℃, 100℃-180℃, 110℃-180℃, 100℃-165℃, or 110℃-165℃.

[0283] Fifth, within the above temperature range, phenolic resin organic particles with better heat resistance can be obtained.

[0284] The sixth temperature is 190℃-290℃, for example, it can be 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, or any combination of the above values.

[0285] Sixth, within the above temperature range, phenolic resin organic particles can be cured more fully, resulting in phenolic resin organic particles with good heat resistance.

[0286] Optionally, the sixth temperature can be 200℃-285℃ or 200℃-280℃.

[0287] Sixth, within the above temperature range, phenolic resin organic particles with better heat resistance can be obtained.

[0288] In some embodiments, the fifth time can be 1h-5h, for example, it 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, or any range of the above values.

[0289] Within the above-mentioned time range, the curing of methyl phenolic resin materials in the fifth stage can be more uniform and complete, thereby obtaining phenolic resin organic particles with better heat resistance.

[0290] In some embodiments, the sixth time can be 1h-6h, for example, it 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, or any range of the above values.

[0291] Sixth, within the above-mentioned time range, phenolic resin organic particles can be cured more fully and have better heat resistance.

[0292] In some embodiments, the first atmosphere may be an inert gas atmosphere or an oxygen-containing atmosphere. An oxygen-containing atmosphere may include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere may be 5%-50%. Optionally, the inert gas may be one or more of nitrogen, argon, and helium, including but not limited to.

[0293] Optionally, the first atmosphere is an oxygen-containing atmosphere, wherein the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More preferably, the first atmosphere can be an air atmosphere.

[0294] In some embodiments, the second atmosphere may be an inert gas atmosphere or an oxygen-containing atmosphere. An oxygen-containing atmosphere may include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere may be 5%-50%. Optionally, the inert gas may be one or more of nitrogen, argon, and helium, including but not limited to.

[0295] Optionally, the second atmosphere is an oxygen-containing atmosphere, wherein the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More preferably, the second atmosphere can be an air atmosphere.

[0296] Amorphous phenolic resins are commercially available or synthesized using methods known in the art. In some embodiments, the preparation method of amorphous phenolic resins includes the following steps: reacting a phenolic compound and an aldehyde compound under the catalysis of an alkaline substance to obtain the amorphous phenolic resin.

[0297] Optionally, the alkaline substance may include one or more of ammonia, NaOH, and Na2CO3.

[0298] Optionally, phenolic compounds may include one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cashew nut shellol.

[0299] Optionally, aldehyde compounds may include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0300] In some embodiments, the organic particles are polymer particles containing triazine ring structural units. The preparation method of the organic particles may include the following steps: providing a precursor containing a triazine ring structure; heating and curing the precursor containing the triazine ring structure in an oxygen-containing atmosphere, followed by crushing and wet grinding to obtain organic particles; the heating and curing temperature is 180℃-290℃. After heating and curing, the precursor containing the triazine ring structure forms a bridging structure between the triazine ring structural units.

[0301] The heat curing temperature is 180℃-290℃, for example, it can be 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, 285℃, 290℃, or any combination of the above values. Heat curing temperatures within the above range can yield polymer particles containing triazine ring structural units with good heat resistance.

[0302] Optionally, the heat curing temperature can be 200℃-285℃, 205℃-285℃, 215℃-285℃, or 225℃-285℃.

[0303] In some embodiments, the heat curing time can be 1-8 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours, 6 hours, 6.2 hours, 6.4 hours, 6.6 hours, 6.8 hours, 7 hours, 7.2 hours, 7.4 hours, 7.6 hours, 7.8 hours, 8 hours, or any combination of the above values. A heat curing time within the above range is beneficial for the formation of polymer particles containing triazine ring structural units from the precursor containing the triazine ring structure, resulting in better heat resistance.

[0304] Optionally, the curing time can be 2h-7h, 2.4h-7h, 2.8h-7h, 2h-6.6h, 2.4h-6.6h, or 2.8h-6.6h.

[0305] In some embodiments, the oxygen-containing atmosphere may include oxygen and an inert gas. Optionally, the inert gas may be one or more of nitrogen, argon, and helium, among others. In some embodiments, the volume fraction of oxygen in the oxygen-containing atmosphere may be 5%-50%. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere may be 10%-30%. More preferably, the oxygen-containing atmosphere may be an air atmosphere.

[0306] In some embodiments, the precursor containing a triazine ring structure may include at least one of the following: melamine aldehyde resin, etherified melamine aldehyde resin, or a mixture of etherified melamine aldehyde resin and at least one of polyol, polycarboxylic acid, or polyamide.

[0307] In some embodiments, the precursor containing a triazine ring structure may include a melamine aldehyde resin, which may be obtained by reacting an aldehyde compound with an amine-substituted triazine compound, wherein the amine-substituted triazine compound may include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 1.75:1-3:1, for example, 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 any range of the above ratios. More preferably, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 2:1-3:1, 2.1:1-3:1, 2.2:1-3:1, 2.3:1-3:1, or 2.4:1-3:1.

[0308] In some embodiments, the precursor containing the triazine ring structure may include an etherified melamine aldehyde resin, which may be obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound. The amine-substituted triazine compound may include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 4:1 to 7:1, for example, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, or any range of the above ratios. More preferably, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 5:1 to 7:1, 5.5:1 to 7:1, 6:1 to 7:1, or 6.5:1 to 7:1.

[0309] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyol, wherein the molar ratio of the etherified melamine aldehyde resin to the polyol may be 1:2 to 1:6.

[0310] In some embodiments, the precursor containing a triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polycarboxylic acid, wherein the molar ratio of the etherified melamine aldehyde resin to the polycarboxylic acid can be 1:2 to 1:6.

[0311] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyamide, wherein the molar ratio of the etherified melamine aldehyde resin to the polyamide may be 1:2 to 1:6.

[0312] In some embodiments, the alcohol compound that forms the etherified melamine aldehyde resin may include one or more of methanol, ethanol, and butanol.

[0313] In some embodiments, the aldehyde compounds forming melamine aldehyde resins and etherified melamine aldehyde resins may include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0314] In some embodiments, the amine-substituted triazine compound forming melamine-formaldehyde resins and etherified melamine-formaldehyde resins may include one or more compounds of the following general formula: R1 and R2 are independently selected from H, -NH2, and C1-C8 alkyl, R3 is selected from H, -NH2, -NHR4, C1-C8 alkyl, C2-C8 alkenyl, phenyl, C7-C12 alkylphenyl, C7-C12 phenylalkyl, and C5-C8 cycloalkyl, and R4 is selected from -NH2 and C1-C8 alkyl. Optionally, R3 is selected from -NH2 or -NHR4.

[0315]

[0316] Optionally, the amine-substituted triazine compound may include melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 6-ethyl-1,3,5-triazine-2,4-diamine, 6-isopropyl-1,3,5-triazine-2,4-diamine, 6-pentyl-2,4-diamino-1,3,5-triazine, 6-heptyl-2,4-diamino-triazine, 2- One or more of the following: 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-triazine-2-yl)methanol, and 2-chloro-4,6-diamino-1,3,5-triazine.

[0317] Alternatively, the amine-substituted triazine compound may include one or more of melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, and 2,4-diamino-6-dimethylamino-1,3,5-triazine.

[0318] Etherified melamine-formaldehyde resins may include one or more of partially etherified and fully etherified melamine-formaldehyde resins. Optionally, etherified melamine-formaldehyde resins may include fully etherified melamine-formaldehyde resins.

[0319] In some embodiments, etherified melamine aldehyde resins may include methyl etherified melamine aldehyde resins, diethyl etherified melamine aldehyde resins, butyl etherified melamine aldehyde resins, and methyl-butyl mixed etherified melamine aldehyde resins.

[0320] Optionally, the etherified melamine-formaldehyde resin may include one or more of the following: methyl etherified melamine-formaldehyde resin, butyl etherified melamine-formaldehyde resin, methyl etherified benzyl melamine-formaldehyde resin, and butyl etherified benzyl melamine-formaldehyde resin.

[0321] This disclosure also provides a secondary battery cell. The secondary battery cell includes the separator provided in this disclosure or the separator prepared by the method of this disclosure. This allows the secondary battery cell to possess both high energy density and high reliability.

[0322] A secondary battery cell also includes a positive electrode, a negative electrode, and an electrolyte, with a separator disposed between the positive and negative electrodes. The positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process.

[0323] The secondary battery cells disclosed herein may include, but are not limited to, lithium battery cells, sodium battery cells, etc. The composition of the positive electrode, negative electrode and electrolyte may differ depending on the type of secondary battery cell.

[0324] [Positive electrode plate]

[0325] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector and comprising a positive electrode active material. For example, the positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0326] Taking a lithium-ion battery cell as an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites, and their respective modified compounds. In some embodiments, to further improve the energy density of the secondary battery cell, the positive electrode active material may include materials with the general formula Li a Ni b Co c M d O e A f One or more of lithium transition metal oxides and their modified compounds. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes but is not limited to one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes but is not limited to one or more of N, F, S and Cl.

[0327] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.1 Al 0.05 One or more of O2, LiFePO4, and LiMnPO4.

[0328] During the charging and discharging process, Li undergoes insertion / extraction and consumption in a single secondary battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to a secondary battery cell, the molar Li content changes after charge-discharge cycles. Similarly, in the examples of positive electrode active materials in this disclosure, the molar O content is only a theoretical value. Lattice oxygen release causes changes in the molar O content, and the actual molar O content will also fluctuate.

[0329] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-x In this case, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes, but is not limited to, H. + Li + Na + K + and NH4 + One or more of the following, M' is a transition metal cation, optionally including but not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally one or more of F, Cl and Br.

[0330] The modified compounds for the positive electrode active materials of the aforementioned lithium battery cells and sodium battery cells can be obtained by doping and / or surface coating modifications of the positive electrode active materials.

[0331] In some embodiments, the positive electrode film layer may further include a positive electrode conductive agent. As an example, the positive electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0332] In some embodiments, the positive electrode film layer may further include a positive electrode binder. As an example, the positive electrode binder may include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0333] In some embodiments, the positive current collector may be a metal foil or a composite current collector. An example of a metal foil is aluminum foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0334] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing positive electrode active materials, positive electrode conductive agents, positive electrode binders, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0335] [Negative electrode plate]

[0336] In some embodiments, the negative electrode sheet may include a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector and comprising a negative electrode active material. For example, the negative current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0337] The negative electrode active material may be any material known in the art for use in secondary battery cells. As an example, the negative electrode active material may include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may include, but are not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include, but are not limited to, one or more of elemental tin, tin oxide, and tin alloys.

[0338] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0339] In some embodiments, the negative electrode film layer may further include a negative electrode binder. As an example, the negative electrode binder may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0340] In some embodiments, the negative electrode film layer may also include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, etc.

[0341] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. As an example of a metal foil, copper foil may be used. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0342] The negative electrode film is typically formed by coating a negative electrode slurry onto a negative electrode current collector, followed by drying and cold pressing. The negative electrode slurry is usually formed by dispersing the negative electrode active material, negative electrode conductive agent, negative electrode binder, and other optional additives in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP) or deionized water, but is not limited to these.

[0343] The negative electrode sheet does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode sheet also includes a conductive undercoat layer (e.g., composed of a conductive agent and a binder) sandwiched between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector.

[0344] In some embodiments, the negative electrode sheet can be made of foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not contain a negative electrode active material.

[0345] [Electrolytes]

[0346] The electrolyte plays a role in conducting ions between the positive and negative electrode plates.

[0347] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0348] Taking a lithium battery cell as an example, the electrolyte salt may include, but is not limited to, one or more of the following: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0349] Taking sodium battery cells as an example, the electrolyte salt may include, but is not limited to, one or more of the following: sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium difluorosulfonyl imide (NaFSI), sodium difluoromethanesulfonyl imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium dioxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0350] In some embodiments, the organic solvent may include, but is not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0351] In some embodiments, the electrolyte may also include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the secondary battery cell, such as additives that improve overcharge performance, additives that improve high-temperature performance, additives that improve low-temperature performance, etc.

[0352] Optionally, the additive may include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), and ethylene sulfate (DTD).

[0353] Methods for preparing secondary battery cells are well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form a secondary battery cell. As an example, the positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process. The electrode assembly is placed in an outer packaging, dried, and then injected with an electrolyte. After standing and formation processes, a secondary battery cell is obtained.

[0354] Example

[0355] The following examples describe the contents of this disclosure in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on mass, and all reagents used in the examples are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0356] Example 1

[0357] Preparation of the separating membrane

[0358] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 34 g styrene, and 6 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water and 15 mg sodium polyacrylate were added to a reactor, and the temperature was raised to 70 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 85 °C and the reaction was allowed to mature for 1.5 hours to obtain a cross-linked styrene-based organic particle emulsion.

[0359] The above emulsion, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate were stirred evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of cross-linked styrene organic particles, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate in the heat-resistant layer slurry was 80:10:2:8.

[0360] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0361] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0362] Preparation of secondary battery cells

[0363] LiNi, the positive electrode active material 0.6 Co 0.2 Mn 0.2O2 and positive electrode binder polyvinylidene fluoride (PVDF) are added to N-methylpyrrolidone (NMP) at a mass ratio of 97:2:1 and mixed thoroughly to prepare a positive electrode slurry. The positive electrode slurry is then uniformly coated onto the positive electrode current collector aluminum foil, and subsequently dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0364] Artificial graphite (anode active material), acetylene black (anode conductive agent), styrene-butadiene rubber (SBR) (anode binder), and sodium carboxymethyl cellulose (thickener) were added to deionized water at a mass ratio of 96.0:1.5:1.5:1. After thorough mixing, a cathode slurry was prepared. The cathode slurry was then uniformly coated onto copper foil (anode current collector), and subsequently dried, cold-pressed, and slit to obtain the cathode sheet.

[0365] At 25°C, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7 to obtain a mixed solvent. LiPF6, vinylene carbonate (VC), and vinyl sulfate (DTD) were then dissolved in this mixed solvent to obtain the electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of VC was 2%, and the mass fraction of DTD was 3%, based on the mass of the electrolyte.

[0366] The positive electrode, separator, and negative electrode are stacked, wound, and hot-pressed in sequence to obtain an electrode assembly. The electrode assembly is placed in an aluminum-plastic film outer packaging, and the electrolyte prepared above is added. After processes such as encapsulation, standing, formation, and aging, a secondary battery cell is obtained.

[0367] Example 2

[0368] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0369] Preparation of the separating membrane

[0370] The solid mass ratio of cross-linked styrene organic particles, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate in the heat-resistant layer slurry is 70:20:2:8.

[0371] Example 3

[0372] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0373] Preparation of the separating membrane

[0374] The solid mass ratio of cross-linked styrene organic particles, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate in the heat-resistant layer slurry is 50:40:2:8.

[0375] Example 4

[0376] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0377] Preparation of the separating membrane

[0378] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-methacryloyloxypropyltriethoxysilane, and 5g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After the addition was complete, the reaction continued for 4 hours, and then the temperature was raised to 84°C for 1.5 hours to mature the reaction, yielding a silicone-containing organic crosslinked resin particle emulsion.

[0379] The above emulsion, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate were stirred evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of the heat-resistant layer slurry containing silicone organic crosslinking resin particles, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate was 50:40:2:8.

[0380] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0381] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0382] Example 5

[0383] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0384] Preparation of the separating membrane

[0385] A commercially available phenolic resin material, consisting of phenol and formaldehyde, was placed in a curing oven. The atmosphere was set to air, and the temperature was set to 135°C. This temperature was maintained for 3 hours. After curing, the oven temperature was increased to 255°C and maintained for another 3 hours. After both curing processes, the cured phenolic resin material was removed and allowed to cool naturally in air. It was then crushed, wet-milled, and wet-demagnetized to obtain a phenolic resin organic particle slurry.

[0386] The above-mentioned slurry, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate were stirred evenly in deionized water to obtain the heat-resistant layer slurry. The solid mass ratio of phenolic resin organic particles, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate in the heat-resistant layer slurry was 50:40:2:8.

[0387] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0388] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0389] Example 6

[0390] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0391] Preparation of the separating membrane

[0392] A commercially available 37% formaldehyde aqueous solution was added to a container, and the pH value was adjusted to 9.0-9.2 with sodium hydroxide aqueous solution. The pH-adjusted mixture was added to a reaction vessel and heated to 50°C under stirring. Melamine was then added to the reaction vessel, with a formaldehyde to melamine molar ratio of 2.5:1. The reaction temperature was raised to 85°C and the reaction was carried out for 9-10 hours to obtain a liquid melamine-formaldehyde methyl resin precursor. When the water turbidity point of the material reached 1:3, the liquid melamine-formaldehyde methyl resin precursor was placed in a drying oven and cured at 200°C in air for 6 hours. After that, it was crushed and wet-milled with water to obtain a polymer particle slurry containing triazine ring structural units.

[0393] The above-mentioned slurry, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate were stirred evenly in deionized water to obtain the heat-resistant layer slurry. The solid mass ratio of the polymer particles containing triazine ring structural units, alumina, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate in the heat-resistant layer slurry was 50:40:2:8.

[0394] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0395] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0396] Comparative Example 1

[0397] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0398] Preparation of the separating membrane

[0399] A pre-emulsion was prepared by emulsifying 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 39.6 g styrene, and 0.4 g divinylbenzene. 140 g deionized water and 15 mg sodium polyacrylate were added to a reactor, and the temperature was raised to 70 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 85 °C and the reaction was allowed to mature for 1.5 hours to obtain a cross-linked styrene-based organic particle emulsion.

[0400] The above-mentioned cross-linked styrene-based organic particle emulsion, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate were stirred and mixed evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of the cross-linked styrene-based organic particles, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate in the heat-resistant layer slurry was 90:2:8.

[0401] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0402] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0403] Performance testing

[0404] (1) Thermal shrinkage rate test of the separator film

[0405] The heat shrinkage rate test of the release liner can be referenced in GB / T 36363-2018.

[0406] Cut the release film into samples with a width of 50mm and a length of 100mm using a punching machine. Take 5 parallel samples and place them on A4 paper. Then place the A4 paper containing the samples on corrugated paper with a thickness of 1mm to 5mm.

[0407] Set the temperature of the forced-air drying oven to 140℃. After the temperature reaches the set temperature and stabilizes for 60 minutes, place the A4 paper placed on the corrugated paper into the forced-air drying oven and start timing. After the set time (1 hour in this disclosure) is reached, measure the length and width of the isolation film, and mark the values ​​as a and b respectively.

[0408] Calculation of heat shrinkage rate: Longitudinal (MD) heat shrinkage rate = [(100-a) / 100]×100%, Transverse (TD) heat shrinkage rate = [(50-b) / 50]×100%, take the average value of 3 parallel samples as the test result.

[0409] (2) Hot box test

[0410] At 25℃, the secondary battery cells were charged to 4.35V at a constant current of 1C, and then charged to 0.05C at a constant voltage of 4.35V. After resting for 5 minutes, each secondary battery cell was tested in a DHG-9070ADHG series high-temperature oven with fixtures. The temperature was increased from room temperature to 60℃ at a rate of 5℃ / min and held for 5 hours. Then, the temperature was increased again at a rate of 5℃ / min, and held for 30 minutes for every 5℃ increase, until the secondary battery cell failed. The oven temperature at the time of secondary battery cell failure was recorded.

[0411] Table 1

[0412]

[0413] The test results above show that the separator disclosed herein has good heat resistance and can improve the thermal safety of secondary battery cells.

[0414] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same essential structure and achieving the same effect as the technical concept within the scope of this disclosure are included in the technical scope of this disclosure. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, are also included in the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A separating membrane, comprising a porous base membrane and a porous coating located on at least one side of the porous base membrane, characterized in that, The porous coating comprises organic particles and inorganic particles, and the organic particles account for a greater mass percentage of the porous coating than the inorganic particles.

2. The separator membrane according to claim 1, characterized in that, The organic particles constitute 50%-93% of the porous coating by mass; and / or, the inorganic particles constitute 5%-45% of the porous coating by mass.

3. The separator membrane according to claim 2, characterized in that, The organic particles constitute 60%-88% of the porous coating by mass; and / or, the inorganic particles constitute 10%-30% of the porous coating by mass.

4. The separator according to any one of claims 1-3, characterized in that, The cyclic voltammetry curve of the organic particles in the first cycle does not show an oxidation peak in the voltage range of 2.5V to 4.4V.

5. The separator according to any one of claims 1-4, characterized in that, The organic particles satisfy one or more of the following conditions (1) to (4): (1) The organic particles have a swelling degree of less than or equal to 3% after being soaked in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days. (2) The dissolution rate of the organic particles after being soaked at 60°C for 7 days in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 is less than or equal to 3%. (3) The organic particles have no melting point; (4) The initial thermal weight loss temperature T of the organic particles 3d ≥240℃.

6. The separator according to any one of claims 1-5, characterized in that, The true density of the organic particles is 1.0 g / cm³. 3 -2.0g / cm 3 ; and / or, The true density of the inorganic particles is 2.5 g / cm³. 3 -3.5g / cm 3 .

7. The separator according to any one of claims 1-6, characterized in that, The organic particles include at least one of thermoplastic resin polymers, thermosetting resin polymers, or cross-linked polymers; Optionally, the thermoplastic resin polymer includes one or more of the following: polycarbonate organic particles, polymethyl methacrylate organic particles, polyoxymethylene organic particles, polyamide organic particles, styrene-acrylonitrile copolymer, polyphenylene sulfide organic particles, polyetheretherketone organic particles, polyimide organic particles, polysulfone organic particles, polyethersulfone organic particles, polyphenylene sulfone organic particles, polybenzimidazole organic particles, polyamide-imide organic particles, and polyethyleneimine organic particles. Optionally, the thermosetting resin polymer includes one or more of the following: phenolic resin organic particles, polymer particles containing triazine ring structural units, epoxy resin organic particles, unsaturated polyester resin organic particles, urea-formaldehyde resin organic particles, and furan resin organic particles. Optionally, the crosslinked polymer includes one or more of crosslinked styrene organic particles and silicon-containing organic crosslinked resin particles.

8. The separator according to any one of claims 1-7, characterized in that, The organic particles include at least one of thermosetting resin polymers or cross-linked polymers; Optionally, the organic particles include one or more of the following: cross-linked styrene organic particles, silicon-containing organic cross-linked resin particles, phenolic resin organic particles, and polymer particles containing triazine ring structural units.

9. The separator according to any one of claims 1-8, characterized in that, The organic particles include cross-linked styrene organic particles, and the cross-linked styrene organic particles include styrene or styrene derivative structural units and cross-linked structural units; Optionally, the styrene or styrene derivative structural unit includes one or more of the following: styrene structural unit, 1-methyl-1-styrene structural unit, 4-methylstyrene structural unit, 2-methylstyrene structural unit, 2,4-dimethylstyrene structural unit, and 2,5-dimethylstyrene structural unit; Optionally, the crosslinking structural unit includes one or more of the following: divinylbenzene structural unit, ethylene glycol dimethacrylate structural unit, pentaerythritol tetraacrylate structural unit, 1,4-butanediol diacrylate structural unit, 1,6-hexanediol diacrylate structural unit, 1,8-octanediol diacrylate structural unit, trimethylolpropane triacrylate structural unit, pentaerythritol trimethacrylate structural unit, tetraethylene glycol dimethacrylate structural unit, tripropylene glycol diacrylate structural unit, N,N-methylenebisacrylamide structural unit, N,N'-vinylbisacrylamide structural unit, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit, and triallyl isocyanurate structural unit.

10. The separator according to any one of claims 1-9, characterized in that, The organic particles include cross-linked styrene organic particles, and the cross-linked styrene organic particles satisfy one or more of the following conditions (1) to (3): (1) The glass transition temperature T of the cross-linked styrene organic particles g The temperature range is 110℃-165℃. (2) The initial thermogravimetric temperature T of the cross-linked styrene organic particles 3d The temperature ranges from 335℃ to 388℃. (3) The volume distribution particle size Dv50 of the cross-linked styrene organic particles is 80nm-300nm.

11. The separator according to any one of claims 1-10, characterized in that, The organic particles include silicon-containing organic crosslinked resin particles, which satisfy one or more of the following conditions (1) to (4): (1) The silicon-containing organic crosslinked resin particles contain a benzene ring structure; (2) The volume distribution particle size Dv50 of the silicon-containing organic crosslinked resin particles is 80nm-800nm; (3) The silicon-containing organic crosslinked resin particles have no glass transition temperature below 300°C; (4) The initial thermogravimetric temperature T of the silicon-containing organic crosslinked resin particles 3d The temperature range is 240℃-330℃.

12. The separator membrane according to claim 11, characterized in that, The silicon-containing organic crosslinked resin particles have a network structure with carbon-carbon bonds as the main chain and side chains containing silicon-oxygen structures and benzene ring structures.

13. The separator according to any one of claims 1-12, characterized in that, The organic particles include silicon-containing organic cross-linked resin particles, the silicon-containing organic cross-linked resin particles include cross-linked structural units, and the cross-linked structural units include divinylbenzene structural units.

14. The separator according to claim 13, characterized in that, The crosslinked structural unit further includes diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate 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, and dipropylene glycol diacrylate. The ester structural unit, 2,2,4-trimethyladipyldi[2-ethylaziridinium] structural unit, 1,1-azeloyldi[2-methylaziridinium] structural unit, 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium] structural unit, trimethylolpropane tris(2-methyl-1-aziridinium propionate) structural unit, trimethylolpropane-tris[3-(2-methylaziridinium)propionate] structural unit, pentaerythritol tris(3-aziridinium)propionate structural unit, or one or more of these structural units.

15. The separator according to any one of claims 1-14, characterized in that, The organic particles include phenolic resin organic particles, and the phenolic resin organic particles satisfy one or more of the following conditions (1) to (4): (1) The phenolic resin organic particles are thermosetting propylene resins; (2) The phenolic resin organic particles have no glass transition temperature below 300℃; (3) The initial thermogravimetric temperature T of the phenolic resin organic particles 3d The temperature range is 300℃-350℃. (4) The volume distribution particle size Dv50 of the phenolic resin organic particles is 160nm-800nm.

16. The separator according to any one of claims 1-15, characterized in that, The organic particles include polymer particles containing triazine ring structural units, and the polymer particles containing triazine ring structural units satisfy one or more of the following conditions (1) to (4): (1) The polymer particles containing triazine ring structural units include bridging structures connecting the triazine ring structural units; (2) The polymer particles containing triazine ring structural units have no glass transition temperature below 300°C; (3) The initial thermogravimetric temperature T of the polymer particles containing the triazine ring structural unit 3d The temperature range is 290℃-340℃. (4) The volume distribution particle size Dv50 of the polymer particles containing triazine ring structural units is 160nm-800nm.

17. The separator membrane according to claim 16, characterized in that, The bridging structure includes one or more combinations of alkylene, alkylene ether, alkylene amine, ester group, and amide group.

18. The separator according to any one of claims 16-17, characterized in that, The polymer particles containing triazine ring structural units also have substituents on the triazine ring structural units, and the substituents include one or more combinations of alkyl, alkenyl, phenyl, cycloalkyl, amino, hydroxyl, and halogen.

19. The separator according to any one of claims 16-18, characterized in that, The polymer particles containing triazine ring structural units include at least one of the following: melamine aldehyde polymers and their derivatives, etherified melamine aldehyde polymers and their derivatives, etherified melamine aldehyde-polyol polymers and their derivatives, etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives, and etherified melamine aldehyde-polyamine amide polymers and their derivatives.

20. The separator according to claim 19, characterized in that, The melamine-formaldehyde polymers and their derivatives include one or more of the following: melamine-formaldehyde, benzyl melamine-formaldehyde, melamine-benzene melamine-formaldehyde, melamine-(2,4-diamino-1,3,5-triazine)formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine)formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine)formaldehyde, trihydrazine-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine)formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine)formaldehyde; and / or, The etherified melamine-formaldehyde polymers and their derivatives include one or more of methyl etherified melamine-formaldehyde, butyl etherified melamine-formaldehyde, methyl etherified benzoyl melamine-formaldehyde, and butyl etherified benzoyl melamine-formaldehyde; and / or The etherified melamine-formaldehyde-polyol polymers and their derivatives include one or more of the following: methyl etherified melamine-formaldehyde-ethylene glycol polymers, methyl etherified melamine-formaldehyde-1,2-propylene glycol polymers, methyl etherified melamine-formaldehyde-1,4-butanediol polymers, methyl etherified melamine-formaldehyde-polyester polyol polymers, methyl etherified melamine-formaldehyde-polyvinyl alcohol polymers, butyl etherified melamine-formaldehyde-ethylene glycol polymers, butyl etherified melamine-formaldehyde-1,2-propylene glycol polymers, butyl etherified melamine-formaldehyde-1,4-butanediol polymers, and butyl etherified melamine-formaldehyde-polyester polyol polymers; and / or... The etherified melamine-formaldehyde-polycarboxylic acid polymers and their derivatives include one or more of the following: methyl etherified melamine-formaldehyde-oxalic acid polymers, methyl etherified melamine-formaldehyde-malonic acid polymers, methyl etherified melamine-formaldehyde-succinic acid polymers, methyl etherified melamine-formaldehyde-citric acid polymers, methyl etherified melamine-formaldehyde-phthalic acid polymers, butyl etherified melamine-formaldehyde-oxalic acid polymers, butyl etherified melamine-formaldehyde-malonic acid polymers, butyl etherified melamine-formaldehyde-citric acid polymers, butyl etherified melamine-formaldehyde-terephthalic acid polymers, and butyl etherified melamine-formaldehyde-phthalic acid polymers; and / or... The etherified melamine aldehyde-polyamine amide polymer and its derivatives include one or more of the following: methyl etherified melamine formaldehyde-glyoxalamide polymer, methyl etherified melamine formaldehyde-malonamide polymer, methyl etherified melamine formaldehyde-isophthalimide polymer, and butyl etherified melamine formaldehyde-glyoxalamide polymer.

21. The separator according to any one of claims 1-20, characterized in that, The volume distribution particle size Dv50 of the inorganic particles is 200nm-800nm; and / or, The inorganic particles include one or more of the following: inorganic particles with a dielectric constant of 5 or higher, inorganic particles with ionic conductivity but without storing ions, or inorganic particles capable of undergoing electrochemical reactions.

22. The separator according to any one of claims 1-21, characterized in that, The porous coating further includes an adhesive; and / or, The thickness of the porous coating is 0.5μm-5μm.

23. A method for preparing the separator membrane according to any one of claims 1-22, comprising the following steps: providing a porous base membrane; providing a slurry comprising organic particles, inorganic particles, and a binder; coating the slurry onto at least one side of the porous base membrane, and drying to obtain the separator membrane.

24. A secondary battery cell, characterized in that, It includes a positive electrode, a negative electrode, and a separator as described in any one of claims 1-22, wherein the separator is disposed between the positive electrode and the negative electrode.

25. A battery device, characterized in that, It includes multiple secondary battery cells as described in claim 24.

26. An electrical appliance, characterized in that, Includes the secondary battery cell of claim 24 or the battery device of claim 25.

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