Separator, secondary battery cell, battery device, and electrical device

Abstract

A separator, a secondary battery cell, a battery device, and an electrical device. The secondary battery cell comprises a positive electrode plate, a negative electrode plate, and a separator. The separator is arranged between the positive electrode plate and the negative electrode plate. The separator comprises a porous base film and a coating disposed on at least one side of the porous base film. The coating comprises organic particles. The dissolution rate of the organic particles after soaking at a constant temperature of 60°C for 7 days in a mixed solvent composed of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 is less than or equal to 3%. The secondary battery cell has high-quality energy density, good charging and discharging performance, and good electrochemical performance.

Description

Separator membrane, secondary battery cell, battery device and electrical device

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410947774.9, filed on July 15, 2024, entitled “Separator, Battery Cell and Electrical Device”, and Chinese Patent Application No. 202411385735.0, filed on September 30, 2024, entitled “Separator, Secondary Battery Cell, Battery Device and Electrical Device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a separator, a secondary battery cell, a battery device, and an electrical device. Background Technology

[0004] As the application range of rechargeable battery cells becomes increasingly wide, the demands on them are also growing, with higher requirements for energy density and electrochemical performance. Therefore, how to enable rechargeable battery cells to possess both high energy density and good electrochemical performance is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] This disclosure provides a separator, a secondary battery cell, a battery device, and an electrical device. The secondary battery cell has high energy density, good charge-discharge performance, and good electrochemical performance.

[0006] In a first aspect, this disclosure provides a secondary battery cell, including a positive electrode, a negative electrode, and a separator. The separator is disposed between the positive electrode and the negative electrode. The separator includes a porous base film and a coating located on at least one side of the porous base film. The coating includes organic particles. The organic particles have a dissolution rate of less than or equal to 3% 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.

[0007] Organic particles have a low density, allowing secondary battery cells to achieve higher gravimetric energy density. In the separator coating of this embodiment, the dissolution rate of organic particles is less than or equal to 3%. This low dissolution rate results in high structural stability during long-term use of the secondary battery cell and high chemical stability in the electrolyte, thereby enabling the secondary battery cell to possess excellent charge-discharge performance and electrochemical performance. Therefore, the separator of this embodiment allows the secondary battery cell to possess high gravimetric energy density, good charge-discharge performance, and good electrochemical performance.

[0008] In some embodiments, the dissolution rate of the organic particles after being soaked at a constant temperature of 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 1.5%.

[0009] This can further improve the electrochemical performance of secondary battery cells.

[0010] In some embodiments, the true density of the organic particles is 1.0 g / cm³. 3 -2.0g / cm 3 ; 1.0 g / cm³ is optional. 3 -1.8g / cm 3 .

[0011] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, and can be selected as 50 nm-820 nm.

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

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

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

[0015] The organic particles disclosed herein have no melting point, indicating that the organic particles have good heat resistance and thermal stability. This allows them to 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.

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

[0017] In some embodiments, the phenolic resin organic particles are thermosetting propylene resin polymers.

[0018] In some embodiments, the phenolic resin organic particles have no glass transition temperature below 300°C.

[0019] In some embodiments, the volume distribution particle size Dv50 of the phenolic resin organic particles is 180nm-820nm.

[0020] In some embodiments, the polymer particles containing triazine ring structural units include bridging structures connecting the triazine ring structural units. Optionally, the bridging structure includes one or more combinations of alkylene, alkylene ether, alkylene amine, ester, and amide groups.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

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

[0029] In some embodiments, the volume distribution particle size Dv50 of the polymer particles containing triazine ring structural units is 180 nm-820 nm.

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

[0031] 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.

[0032] 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.

[0033] In some embodiments, the glass transition temperature T of the cross-linked styrene organic particles g The temperature ranges from 110℃ to 156℃.

[0034] In some embodiments, the volume distribution particle size Dv50 of the cross-linked styrene organic particles is 90 nm-310 nm.

[0035] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, which contain carbon-carbon bonds and silicon-oxygen structures.

[0036] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, wherein the silicon-containing organic resin particles are a network structure formed with carbon-carbon bonds as the main chain and the side chains contain silicon-oxygen structures.

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

[0038] Optionally, the crosslinked structural units include divinylbenzene structural units, 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.

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

[0040] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles is 90nm-310nm.

[0041] In some embodiments, the ratio of the volume distribution particle size Dv50 of the organic particles to the average pore size of the porous base membrane is greater than or equal to 1.2.

[0042] In some embodiments, the coating further includes an adhesive.

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

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

[0045] In some embodiments, the areal density of the coating is 0.45 g / m³. 2 -5g / m 2 .

[0046] Secondly, this disclosure provides a battery device comprising a plurality of secondary battery cells according to the first aspect of this disclosure.

[0047] Thirdly, this disclosure provides an electrical device that includes a secondary battery cell according to the first aspect of this disclosure or a battery device according to the second aspect of this disclosure.

[0048] Fourthly, this disclosure provides a separating membrane, comprising a porous base membrane and a coating located on at least one side of the porous base membrane, the coating comprising organic particles, wherein the organic particles have a dissolution rate of less than or equal to 3% 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.

[0049] In some embodiments, the true density of the organic particles is 1.0 g / cm³. 3 -2.0g / cm 3 ; 1.0 g / cm³ is optional. 3 -1.8g / cm 3 .

[0050] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, and can be selected as 50 nm-820 nm.

[0051] In some embodiments, the organic particles are at least one of a thermosetting resin polymer or a crosslinked polymer.

[0052] In some embodiments, the organic particles are amorphous polymers.

[0053] In some embodiments, the organic particles have no melting point.

[0054] In some embodiments, the organic particles include one or more of the following: phenolic resin organic particles, polymer particles containing triazine ring structural units, cross-linked styrene organic particles, and silicon-containing organic resin particles. Attached Figure Description

[0055] 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.

[0056] Figure 1 shows a schematic diagram of a secondary battery cell provided in some embodiments of this disclosure.

[0057] Figure 2 shows a schematic diagram of an electrical device provided in some embodiments of this disclosure.

[0058] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0059] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the separator, secondary battery cell, battery device, and power-consuming 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0066] 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.

[0067] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0068] The secondary battery cell mentioned in the embodiments of this disclosure can independently perform charge and discharge functions. After discharge, it can be recharged to activate the active materials and continue to be used. The secondary battery cell can be cylindrical, cuboid, or other shapes, etc., and the embodiments of this disclosure are not limited to this. Figure 1 shows a cuboid secondary battery cell 5 as an example.

[0069] 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.

[0070] 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).

[0071] 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.

[0072] In some embodiments, a battery cell assembly is typically formed by arranging multiple secondary battery cells.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple secondary battery cells to the housing.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] Figure 2 is a schematic diagram of an example electrical device. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0082] In the context of this disclosure, the "organic particles" in the coating of the separator primarily serve to improve heat resistance and have almost no adhesive properties.

[0083] The separator is a crucial component supporting the electrochemical processes of charging and discharging in a secondary battery cell. Commonly used separators are mostly made of polyolefin materials; however, these materials have low glass transition temperatures and exhibit significant thermal shrinkage upon heating. To improve the heat resistance of the separator, boehmite or alumina is often used as a heat-resistant filler and binder to construct the coating. Boehmite and alumina have high densities; for the same packing volume, their mass is greater than other materials, thus affecting the energy density of the secondary battery cell.

[0084] This disclosure provides a separator that enables secondary battery cells to possess high energy density, good charge-discharge performance, and good electrochemical performance.

[0085] The separating membrane provided in this disclosure includes a porous base membrane and a coating located on at least one side of the porous base membrane. The coating includes organic particles and a binder. The dissolution rate of the organic particles after immersion 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%.

[0086] Both the porous base membrane and the coating have a porous structure, which gives the separator good air permeability and facilitates ion passage. The organic particles in the coating are interconnected and fixed by a binder, and the gaps between the organic particles can form a porous structure.

[0087] Organic particles have a low density, and secondary battery cells using them can have a higher mass energy density.

[0088] The preparation of secondary battery cells requires the addition of an electrolyte, which includes electrolyte salts and organic solvents. The dissolution behavior of organic particles in the electrolyte is dominated by ionic energy, while the dissolution behavior of organic particles in organic solvents is more significantly affected by mixing energy. Furthermore, organic solvent molecules are small and easily penetrate the molecular chains of heat-resistant organic particles, causing swelling of unstable sites. Currently, conventional organic particles dissolve in large quantities in organic solvents. After significant dissolution, the structural stability of the organic particles deteriorates, leading to decreased chemical stability in the electrolyte when used in secondary battery cells, making them prone to side reactions with the electrolyte. Simultaneously, the dissolved components may also affect the electrolyte's own properties, such as viscosity and conductivity, which in turn affects the charge-discharge performance of the secondary battery cell. In the embodiments of this disclosure, the dissolution rate of organic particles in the separator coating is less than or equal to 3%. This low dissolution rate results in higher structural stability and higher chemical stability in the electrolyte during long-term use of the secondary battery cell, thereby enabling the secondary battery cell to exhibit excellent charge-discharge performance and electrochemical performance.

[0089] Therefore, the separator of the present invention can enable secondary battery cells to have high energy density, good charge and discharge performance and good electrochemical performance.

[0090] In some embodiments, the dissolution rate of organic particles 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 can be less than or equal to 1.5%.

[0091] This can further improve the electrochemical performance of secondary battery cells.

[0092] Dissolution rate = (mass of organic particles dissolved in the mixed solvent) / initial mass of organic particles × 100%.

[0093] 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.

[0094] In some embodiments, the true density of the organic particles can be 1.0 g / cm³. 3 -2.0g / cm 3 Optionally, the true density of the organic particles can be 1.0 g / cm³. 3 -1.8g / cm 3 .

[0095] Currently, the true density of inorganic particles such as boehmite and alumina is typically 2.5 g / cm³. 3 -3.5g / cm 3 The organic particles disclosed herein have a low true density, thereby enabling secondary battery cells using the separator of this disclosure to have a higher mass energy density.

[0096] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, and can be selected as 50 nm-820 nm or 90 nm-820 nm.

[0097] The organic particles disclosed herein 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 their molecular weight cannot be determined by gel permeation chromatography.

[0098] The organic particles disclosed herein are at least one of thermosetting resin polymers or cross-linked polymers.

[0099] Thermosetting resin polymers are polymer products that harden irreversibly during curing. Once cured, they do not soften or melt when heated again.

[0100] Cross-linked polymers are polymer products obtained when cross-linking bonds are formed between monomer units.

[0101] The organic particles disclosed herein are amorphous polymers.

[0102] In some embodiments, the organic particles have no melting point.

[0103] The organic particles disclosed herein have no melting point, indicating that the organic particles have good heat resistance and thermal stability. This allows them to 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] 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℃.

[0105] Organic particles have no melting point, meaning that the DSC curve of organic particles does not have a melting peak.

[0106] In some embodiments, the organic particles may include one or more of the following: phenolic resin organic particles, polymer particles containing triazine ring structural units, cross-linked styrene organic particles, and silicon-containing organic resin particles.

[0107] [Phenolic resin organic particles]

[0108] In some embodiments, the phenolic resin organic particles are thermosetting resin polymers.

[0109] In some embodiments, the phenolic resin organic particles are thermosetting propylene resin polymers.

[0110] The raw materials for phenolic resin organic particles may include phenolic compounds and aldehyde compounds. In some embodiments, the phenolic compounds may include one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cashew nut shell powder. In some embodiments, the aldehyde compounds may include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0111] In some embodiments, phenolic resin organic particles have no glass transition temperature below 300°C.

[0112] Phenolic resin organic particles have no glass transition temperature below 300℃, indicating that the organic particles have good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0113] In some embodiments, the volume distribution particle size Dv50 of phenolic resin organic particles can be 180nm-820nm.

[0114] The volume distribution particle size Dv50 of phenolic resin organic particles within the above range is beneficial for the separator to have good heat resistance and air permeability.

[0115] Phenolic resin materials generally exhibit high dissolution rates in organic solvents, which cannot meet the requirements of separator membranes. Therefore, this disclosure provides phenolic resin organic particles with a dissolution rate of less than or equal to 3% when 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. This disclosure also provides a method for preparing these phenolic resin organic particles.

[0116] In some embodiments, the method for preparing phenolic resin organic particles includes the following steps: providing a primary phenolic resin material; curing the primary phenolic resin material at a first temperature and a first atmosphere for a first time, then curing it at a second temperature and a second atmosphere for a second time, followed by crushing to obtain phenolic resin organic particles. The first temperature is 90℃-170℃, and the second temperature is 200℃-280℃.

[0117] Existing curing processes for methyl phenolic resin materials often involve curing at room temperature or at temperatures below 150°C. These methods fail to ensure complete curing, resulting in a relatively high dissolution rate of the obtained phenolic resin organic particles. This disclosure addresses this issue by performing segmented curing of the methyl phenolic resin material and adjusting the curing temperature for each segment, thereby obtaining phenolic resin organic particles with good heat resistance and a low dissolution rate.

[0118] The preparation method provided in this embodiment is simple and does not require complex operations, thus also having low production costs.

[0119] The phenolic resin organic particles prepared in this disclosure are thermosetting propylene resin polymers.

[0120] The first temperature is 90℃-170℃, for example, it can be 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃, 170℃, or any range of the above values.

[0121] Within the aforementioned temperature range, the curing of methyl phenolic resin materials in the first stage can be more uniform and complete, thereby yielding phenolic resin organic particles with a lower dissolution rate.

[0122] Optionally, the first temperature can be 100℃-165℃, 110℃-160℃, 100℃-160℃, or 110℃-160℃.

[0123] The second temperature is 200℃-280℃, for example, it can be 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, or any range of the above values.

[0124] The second temperature, within the above range, allows phenolic resin organic particles to cure more fully and has a lower dissolution rate.

[0125] Optionally, the second temperature can be 210℃-280℃ or 210℃-270℃.

[0126] In some embodiments, the first time can be 2h-5h, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or any range of the above values.

[0127] Within the aforementioned range, the curing of methyl phenolic resin materials in the first stage can be more uniform and complete, thereby obtaining phenolic resin organic particles with a lower dissolution rate.

[0128] In some embodiments, the second 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.

[0129] Secondly, within the above-mentioned time range, phenolic resin organic particles can be cured more fully and have a lower dissolution rate.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] In some embodiments, the method for preparing phenolic resin organic particles may further include sieving and demagnetizing steps after crushing.

[0135] 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.

[0136] Optionally, the molar ratio of the phenolic hydroxyl group of the phenolic compound to the aldehyde group of the aldehyde compound can be from 1:1.1 to 1:1.5.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[0170] In some embodiments, the volume distribution particle size Dv50 of polymer particles containing triazine ring structural units can be 180 nm-820 nm.

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

[0172] This disclosure provides polymer particles containing triazine ring structural units, wherein the dissolution rate of these particles after immersion 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%. Embodiments of this disclosure also provide a method for preparing these polymer particles containing triazine ring structural units.

[0173] In some embodiments, a method for preparing polymer particles containing triazine ring structural units includes the following steps: providing a precursor containing a triazine ring structure; heating and curing the precursor containing a triazine ring structure under an oxygen-containing atmosphere, followed by crushing, to obtain polymer particles containing a triazine ring structure. The precursor containing a triazine ring structure includes 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, and polyamide. Melamine aldehyde resin is obtained by reacting an aldehyde compound with an amine-substituted triazine compound, wherein the molar ratio of the aldehyde compound to the amine-substituted triazine compound is 1.9:1-3:1. Etherified melamine aldehyde resin is obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound, wherein the molar ratio of the aldehyde compound to the amine-substituted triazine compound is 6:1-7:1. The amine-substituted triazine compound includes melamine and / or melamine derivatives.

[0174] When a precursor containing a triazine ring structure is heated and cured, a bridging structure is formed between the triazine ring structural units.

[0175] Melamine-formaldehyde resins are obtained by reacting aldehyde compounds with amine-substituted triazine compounds. The molar ratio of the aldehyde compound to the amine-substituted triazine compound is 1.9:1 to 3:1, for example, it can be 1.9:1, 2:1, 2.05:1, 2.1:1, 2.15:1, 2.2:1, 2.25:1, 2.3:1, 2.35:1, 2.4:1, 2.45:1, 2.5:1, 2.55:1, 2.6:1, 2.65:1, 2.7:1, 2.75:1, 2.8:1, 2.85:1, 2.9:1, 2.95:1, 3:1, or any range of the above ratios. Optionally, the molar ratio of aldehyde compounds to amine-substituted triazine compounds can be 2.05:1-3:1, 2.15:1-3:1, 2.25:1-3:1, or 2.3:1-3:1.

[0176] Etherified melamine-formaldehyde resins are obtained by reacting aldehyde compounds, amine-substituted triazine compounds, and alcohol compounds. The molar ratio of the aldehyde compound to the amine-substituted triazine compound is 6:1-7:1, for example, 6:1, 6.1:1, 6.2:1, 6.3:1, 6.4:1, 6.5:1, 6.6:1, 6.7:1, 6.8:1, 6.9:1, 7:1, or any range of the above ratios. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 6.2:1-7:1 or 6.4:1-7:1.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] In some embodiments, the alcohol compound that forms the etherified melamine aldehyde resin may include one or more of methanol, ethanol, and butanol.

[0181] 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.

[0182] 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.

[0183] Optionally, the amine-substituted triazine compound may include melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 6-ethyl-1,3,5-triazine-2,4-diamine, 6-isopropyl-1,3,5-triazine-2,4-diamine, 6-pentyl-2,4-diamino-1,3,5-triazine, 6-heptyl-2,4-diamino-triazine, 2-ethyl Alkenyl-4,6-diamino-1,3,5-triazine, 2,4-diamino-6-(4-methylphenyl)-1,3,5-triazine, 6-cyclohexyl-1,3,5-triazine-2,4-diamine, 6-(3-methylphenyl)-1,3,5-triazine-2,4-diamine, 6-o-tolyl-1,3,5-triazine-2,4-diamine, 6-(2,4-dimethylphenyl)-1,3,5-triazine-2,4-diamine, 6-phenylmethyl-1,3,5-triazine-2,4-diamine, (diamino-1,3,5-triazine-2-yl)methanol, and 2-chloro-4,6-diamino-1,3,5-triazine.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] 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.

[0188] In some embodiments, the etherified melamine aldehyde resin may be in liquid form.

[0189] In some embodiments, the heat curing temperature can be 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 range of the above values.

[0190] Heating and curing temperatures within the above range are beneficial for precursors containing triazine ring structures to form polymer particles with lower dissolution rates.

[0191] Optionally, the heat curing temperature can be 200℃-290℃, 210℃-290℃, 220℃-290℃, 230℃-290℃, 200℃-280℃, 210℃-280℃, 220℃-280℃, or 230℃-280℃.

[0192] In some embodiments, the heating curing time can be 3h-6h, for example, it can be 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.

[0193] When the heating and curing time is within the above range, it is beneficial for the precursor containing the triazine ring structure to form polymer particles with a lower dissolution rate.

[0194] 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.

[0195] In some embodiments, polymer particles containing triazine ring structural units may further include sieving and demagnetization steps after crushing.

[0196] [Cross-linked styrene organic particles]

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

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

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

[0200] In some embodiments, the glass transition temperature T of cross-linked styrene organic particles g It can be between 110℃ and 156℃.

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

[0202] In some embodiments, the volume distribution particle size Dv50 of the cross-linked styrene organic particles can be 90 nm-310 nm.

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

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

[0205] In some embodiments, the method for preparing crosslinked styrene-based organic particles includes the following steps: providing a pre-emulsion comprising monomers, crosslinking agents, emulsifiers, initiators, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain crosslinked styrene-based organic particles; the monomers include one or more of styrene and its derivatives; the mass fraction of the crosslinking agent is 5%-32% based on the total mass of monomers and crosslinking agents as 100%; the ripening temperature of the emulsion polymerization reaction is 70℃-85℃, and the ripening time of the emulsion polymerization reaction is 1h-6h.

[0206] Based on the total mass of monomers and crosslinking agents as 100%, the mass fraction of the crosslinking agent is 5%-32%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, or any combination of the above values.

[0207] When the mass fraction of the crosslinking agent is within the above range, it can improve the heat resistance of crosslinked styrene organic particles and reduce the dissolution rate of crosslinked styrene organic particles.

[0208] Optionally, the mass fraction of the crosslinking agent can be 8%-32%.

[0209] The maturation temperature for emulsion polymerization is 70℃-85℃, for example, it can be 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, or any range of the above values. Optionally, the maturation temperature for emulsion polymerization is 72℃-85℃.

[0210] The maturation time for emulsion polymerization is 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.

[0211] When the curing temperature and curing time of the emulsion polymerization reaction are within the above range, the heat resistance of cross-linked styrene organic particles can be improved and the dissolution rate of cross-linked styrene organic particles can be reduced.

[0212] In some embodiments, the emulsion polymerization reaction may include the following steps: adding a pre-emulsion dropwise into a reactor containing water under a first heating temperature, inert gas protection, and stirring conditions; after a first reaction time, raising the temperature to a ripening temperature for ripening reaction to obtain cross-linked styrene-based organic particles.

[0213] Optionally, the first heating temperature can be 55℃-70℃.

[0214] Optionally, the first time can be 3h-6h.

[0215] In some embodiments, the monomer may include one or more of styrene, 1-methyl-1-styrene, 4-methylstyrene, 2-methylstyrene, 2,4-dimethylstyrene, and 2,5-dimethylstyrene.

[0216] The crosslinking agent polymerizes with the monomer to form crosslinked structural units of crosslinked styrene-based organic particles. In some embodiments, the crosslinking agent may include one or more of the following: divinylbenzene, ethylene glycol dimethacrylate, pentaerythritol tetraacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, N,N-methylenebisacrylamide, N,N'-vinylbisacrylamide, 1,3,5-triacryloylhexahydro-1,3,5-triazine, and triallyl isocyanurate.

[0217] Optionally, the crosslinking agent may include one or more of divinylbenzene, N,N-methylenebisacrylamide, and N,N'-vinylbisacrylamide.

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

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

[0220] In some embodiments, the mass fraction of the emulsifier may be 0.1%-3% based on the total mass of monomers and crosslinking agents (100%).

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

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

[0223] [Silicone-containing organic resin granules]

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

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

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

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

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

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

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

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

[0232] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles can be 90 nm-310 nm.

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

[0234] This disclosure provides a silicon-containing organic resin particle whose dissolution rate is less than or equal to 3% when immersed in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days. This disclosure also provides a method for preparing the silicon-containing organic resin particle.

[0235] In some embodiments, the method for preparing silicone-containing organic resin particles includes the following steps: providing a pre-emulsion comprising monomers, crosslinking agents, emulsifiers, initiators, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain silicone-containing organic resin particles; wherein the monomers include silane coupling agents containing alkenyl groups and / or acryloyloxy groups; and the mass fraction of the crosslinking agent is 5%-16% based on the total mass of monomers and crosslinking agents as 100%.

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

[0237] Based on the total mass of monomers and crosslinking agents as 100%, the mass fraction of the crosslinking agent is 5%-16%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, or any combination of the above values. A mass fraction of 5%-16% for the crosslinking agent can improve the heat resistance of silicone-containing organic resin particles and reduce the dissolution rate of silicone-containing organic resin particles.

[0238] Optionally, the mass fraction of the crosslinking agent can be 8%-16% or 8%-14%.

[0239] When the mass fraction of the crosslinking agent is within the above range, it can further improve the heat resistance of the silicon-containing organic resin particles, further reduce the dissolution rate of the silicon-containing organic resin particles, and also improve the high-temperature performance of the secondary battery cell.

[0240] The crosslinking agent and monomers polymerize to form crosslinked structural units of silicon-containing organic crosslinked resin particles.

[0241] In some embodiments, the crosslinking agent may be a multifunctional crosslinking agent.

[0242] Optionally, the crosslinking agent may include one or more of the following: divinylbenzene, diethylene glycol divinyl ether, triethylene glycol divinyl ether, diallyl maleate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-nonaiyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0243] In some embodiments, the monomer may include a vinylsilane coupling agent and / or an acryloyloxysilane coupling agent.

[0244] Optionally, the monomer may include γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-tert-butoxyvinylsilane, vinyltri... One or more of the following: (β-methoxyethoxy)silane, ethylenetri[(1-methylvinyl)oxy]silane, vinyltritert-butylperoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane.

[0245] In some embodiments, a monomer may include a first monomer and a second monomer.

[0246] The first monomer may include one or more of the following: γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tritert-butoxyvinylsilane, vinyltris(β-methoxyethoxy)silane, ethylenetris[(1-methylvinyl)oxy]silane, and vinyltritert-butylperoxysilane.

[0247] The second monomer may include one or more of the following: 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane.

[0248] The first and second monomers have different activities. By combining them and reacting them with a crosslinking agent, silicone organic resin particles with a narrow particle size distribution can be obtained.

[0249] In some embodiments, the emulsifier may be one or more of alkyl sulfates, alkyl sulfonates, Tween emulsifiers, fatty alcohol polyoxyethylene ethers, fatty alcohol polyoxypropylene ethers, cetearyl alcohol polyethers, and oleyl alcohol polyethers.

[0250] Optionally, the emulsifier may include one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, Tween 20, Tween 40, lauryl ether-7, lauryl ether-9, lauryl ether-10, and oleyl ether-10.

[0251] In some embodiments, the initiator may be one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyronitrile, azobisisobutyramidine hydrochloride, azobisisobutyramidine imidazoline hydrochloride, and azobisisopropylimidazoline.

[0252] In some embodiments, the mass fraction of the initiator, based on the total mass of monomers and crosslinking agents (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 initiator can be 0.3%-2.1%, 0.3%-1.9%, 0.3%-1.7%, 0.3%-1.5%, or 0.3%-1.3%.

[0253] When the mass fraction of the initiator is within the above range, the heat resistance of the silicon-containing organic resin particles can be further improved, the dissolution rate of the silicon-containing organic resin particles can be further reduced, and the high-temperature performance of the secondary battery cell can also be improved.

[0254] In some embodiments, the heating temperature during the ripening stage of the emulsion polymerization reaction can be 75°C-88°C, for example, it can be 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, or any range of the above values.

[0255] In some embodiments, the heating time for the ripening stage of the emulsion polymerization reaction can be 1h-4h, 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, or any range of the above values.

[0256] In some embodiments, the emulsion polymerization reaction may include the following steps: adding a pre-emulsion dropwise into a reactor containing water under a second heating temperature, inert gas protection, and stirring conditions; after a second reaction time, raising the temperature to the heating temperature of the maturation stage to carry out the maturation reaction, thereby obtaining the emulsion.

[0257] Optionally, the second heating temperature can be 55℃-70℃.

[0258] Optionally, the second time can be 3h-6h.

[0259] 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.

[0260] In some embodiments, the method for preparing silicone organic resin particles may further include a demagnetization treatment step after the emulsion polymerization reaction is completed.

[0261] Glass transition temperature T gThe test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The glass transition temperature Tg of the organic particles can be obtained through the DSC curve, or it can be used to determine whether the organic particles have a glass transition temperature Tg. g .

[0262] 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.

[0263] 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℃.

[0264] Dv50 represents the particle size corresponding to a cumulative volumetric distribution percentage of 50% for the material. It can be measured using a laser particle size analyzer, referring to GB / T 19077-2016. During testing, add 1g of the sample to a clean small beaker, along with 20ml of deionized water. Sonicate at 53kHz / 120W for 5 minutes to ensure complete dispersion. Turn on the laser particle size analyzer, clean the optical path system, and automatically test the background. Stir the sonicated solution to ensure uniform dispersion, then place it in the sample cell as required and begin measuring the particle size. A MasterSizer 3000 laser particle size analyzer can be used as the testing instrument.

[0265] In some embodiments, the organic particle content in the coating may be 50%-99% based on the total mass of the coating.

[0266] Optionally, the mass content of organic particles in the coating can be 60%-99%, 70%-99%, 80%-99%, 85%-99%, 88%-99%, 80%-97%, 85%-97%, 88%-97%, 80%-95%, 85%-95%, or 88%-95%.

[0267] In some embodiments, the binder in the coating may include, but is not limited to, one or more of the following: polyacrylate binders, nitrile rubber binders, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0268] In some embodiments, the coating may also include a dispersant, such as, but not limited to, polyacrylic acid dispersants or carboxymethyl cellulose dispersants. As an example, the dispersant may include, but is not limited to, one or more of sodium carboxymethyl cellulose, sodium polyacrylate, and ammonium polyacrylate.

[0269] In some embodiments, the separator may further include polymer binder particles. These polymer binder particles serve to improve the adhesion between the separator and the electrode, and they are essentially not heat-resistant.

[0270] In some embodiments, polymer binder particles may be embedded in organic particles and form protrusions on the coating surface.

[0271] In other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on the porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the heat-resistant layer on the side away from the porous base membrane. Organic particles are disposed in the heat-resistant layer, and polymer binder particles are disposed in the adhesive layer.

[0272] In some other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer, the heat-resistant layer being disposed on one side of the porous base membrane, the adhesive layer being disposed on at least a portion of the surface of the other side of the porous base membrane, organic particles being disposed in the heat-resistant layer, and polymer binder particles being disposed in the adhesive layer.

[0273] In some embodiments, the average particle size of the polymer binder particles can be 6 μm-18 μm.

[0274] The average particle size of the test particles can be tested as follows: Using a scanning electron microscope (SEM) according to JY / T 010-1996, obtain an SEM image of the separator. Randomly select a test sample with dimensions of 50mm x 100mm on the separator. Randomly select multiple test areas (e.g., 5) within the test sample, and read the particle size of the test particles in each test area at a certain magnification (e.g., 500x or higher). Count the number and particle size values ​​of the test particles in each test area, and take the arithmetic mean of the particle sizes in all test areas as the average particle size. To ensure the accuracy of the test results, multiple test samples (e.g., 10) can be used for the above test, and the average value of each test sample can be taken as the final test result. The testing instrument can be a ZEISS Sigma 300. It should be noted that when the test particles are irregularly shaped, the distance between the two farthest points on the test particle should be taken as the particle size.

[0275] 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.

[0276] Comonomers may include at least one of olefin monomers, fluorinated olefin monomers, chlorinated olefin monomers, acrylate monomers, acrylic monomers, and fluoroether monomers.

[0277] 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).

[0278] In some embodiments, the coating thickness can be 0.5 μm-5 μm. The coating thickness refers to the thickness of the coating on one side of the porous base membrane. Optionally, the coating thickness can be 0.5 μm-4 μm, 0.5 μm-3 μm, 0.5 μm-2 μm, 0.6 μm-4 μm, 0.6 μm-3 μm, 0.6 μm-2 μm, 0.8 μm-4 μm, 0.8 μm-3 μm, or 0.8 μm-2 μm.

[0279] In some embodiments, the areal density of the coating may be 0.45 g / m³. 2 -5g / m 2 .

[0280] 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.

[0281] 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.

[0282] In some embodiments, the thickness of the porous base film can be 4μm-12μm, and optionally 4μm-9μm.

[0283] In some embodiments, the porosity of the porous base membrane can be 25%-60%, optionally 28%-50%.

[0284] In some embodiments, the ratio of the volume distribution particle size Dv50 of the organic particles to the average pore size of the porous base membrane can be greater than or equal to 1.2.

[0285] The volume distribution particle size Dv50 of the organic particles has the same unit, e.g., nm, as the average pore size of the porous membrane.

[0286] This can reduce pore blockage and improve the air permeability and ion conduction properties of the separator.

[0287] In some embodiments, the average pore size of the porous base film can be 25 nm to 82 nm.

[0288] The average pore size of the porous membrane can be measured using a capillary porosity analyzer (bubble point method). An exemplary testing method is as follows: Take a circular sample with a diameter of 25 mm, and drop 3-5 drops of wetting solution onto it. After the sample is completely wetted, place it in a mold. Then, use an inert gas (such as nitrogen) to compress the wetting solution in the pores of the sample. The compression pressure and flow rate are inversely proportional to the pore size. The average pore size of the sample is obtained through software sampling and pressure-pore size conversion analysis. The testing instrument can be a PMI CFP 1500 pore size analyzer, with a testing pressure ranging from 100 psi to 350 psi.

[0289] 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.

[0290] It should be noted that the coating parameters of the above-mentioned separators are coating parameters for one side of the porous base membrane. When the coating is applied to both sides of the porous base membrane, if the coating parameters of either side meet the requirements of this disclosure, it is considered to fall within the protection scope of this disclosure.

[0291] The separator membrane can be prepared according to methods known in the art.

[0292] In some embodiments, a slurry including organic particles and a binder can be coated on at least one side of a porous base membrane, and after drying, a separation membrane is obtained.

[0293] In some embodiments, the slurry may further include polymer binder particles, which, after drying, are embedded in organic particles and form protrusions on the coating surface.

[0294] In some embodiments, the method for preparing the separator membrane may include: applying a heat-resistant layer slurry comprising organic particles and a binder to at least one side of a porous base membrane, and drying it to form a heat-resistant layer; and applying an adhesive layer slurry comprising polymer binder particles and a binder to at least a portion of the surface of the heat-resistant layer, and drying it to obtain the separator membrane.

[0295] In some embodiments, the method for preparing the separator membrane may include: coating a heat-resistant slurry comprising organic particles and a binder onto one side of a porous base membrane, and coating an adhesive layer slurry comprising polymer binder particles and a binder onto at least a portion of the surface of the other side of the porous base membrane, and drying the slurry to obtain the separator membrane.

[0296] In some embodiments, the solvent for the slurry may be water, such as deionized water.

[0297] In some embodiments, the slurry may also include other components, such as dispersants and / or wetting agents.

[0298] This disclosure also provides a secondary battery cell. The secondary battery cell includes the separator provided in this disclosure.

[0299] 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.

[0300] 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.

[0301] [Positive electrode plate]

[0302] 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.

[0303] Taking a lithium-ion battery cell as an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites, and their respective modified compounds. In some embodiments, to further improve the energy density of the secondary battery cell, the positive electrode active material may include materials with the general formula Li a Ni b Co c Md 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.

[0304] 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.

[0305] 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. As 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, leading to fluctuations in the actual molar O content.

[0306] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-x In this case, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes, but is not limited to, H. + Li + Na + K + and NH4 + One or more of the following, M' is a transition metal cation, optionally including but not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally one or more of F, Cl and Br.

[0307] 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.

[0308] 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.

[0309] 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.

[0310] 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.

[0311] 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.

[0312] [Negative electrode plate]

[0313] 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.

[0314] 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.

[0315] 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.

[0316] 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).

[0317] 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.

[0318] 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.

[0319] 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.

[0320] 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.

[0321] 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.

[0322] [Electrolytes]

[0323] The electrolyte plays a role in conducting ions between the positive and negative electrode plates.

[0324] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0325] 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).

[0326] 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).

[0327] 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.

[0328] 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.

[0329] Optionally, the additive may include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), and ethylene sulfate (DTD).

[0330] Methods for preparing secondary battery cells are well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form a secondary battery cell. As an example, the positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process. The electrode assembly is placed in an outer packaging, dried, and then injected with the aforementioned electrolyte. After vacuum sealing, settling, and formation processes, a secondary battery cell is obtained.

[0331] Example

[0332] The following embodiments describe the disclosure of this disclosure in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0333] 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 130°C. This temperature was maintained for 3 hours. After curing, the oven temperature was increased to 245°C and maintained for 4 hours. After both curing cycles, the cured phenolic resin material was removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles 1-1#.

[0334] A commercially available phenolic resin material, consisting of phenol and formaldehyde, was placed in a curing oven. The atmosphere was set to air, and the temperature was set to 130°C. This temperature was maintained for 3 hours. After curing, the oven temperature was increased to 215°C and maintained for 5 hours. After both curing cycles, the cured phenolic resin material was removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles #1-2.

[0335] 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 130°C. This temperature was maintained for 3 hours. After curing, the oven temperature was increased to 265°C and maintained for another 3 hours. After both curing cycles, the cured phenolic resin material was removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles #1-3.

[0336] A commercially available phenolic resin material, consisting of phenol and formaldehyde, was placed in a curing oven. The atmosphere was set to air, and the temperature was set to 350℃. The curing was maintained at this temperature for 4 hours. After curing, the cured phenolic resin material was removed, allowed to cool naturally in air, and then crushed, milled, sieved, and demagnetized to obtain phenolic resin organic particles D1-1#.

[0337] Organic Particle Performance Testing

[0338] (1) Glass transition temperature T of organic particles g test

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

[0340] (2) Melting point test of organic particles

[0341] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. Determine whether the organic particles have a melting point using the DSC curve.

[0342] (3) Dissolution rate test of organic particles

[0343] 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.

[0344] The organic particles 1-1# to 1-3# prepared above meet the following characteristics: the phenolic resin organic particles are thermosetting propylene resin polymers, which have no melting point and no glass transition temperature T below 300℃. g .

[0345] Next, the organic particles prepared above were used in the separator to verify their impact on the performance of the separator and the secondary battery cells.

[0346] The preparation process of the separator membrane is as follows.

[0347] A commercially available 7 μm thick polyethylene microporous membrane was used as the porous base membrane. The prepared organic particles, dispersant sodium carboxymethyl cellulose, and binder polyacrylate were mixed evenly in deionized water at a solid mass ratio of 90:2:8 to obtain a slurry. The slurry was uniformly coated onto both surfaces of the porous base membrane, and dried to remove the solvent, resulting in a separating membrane. The coating thickness was 1.5 μm, and the separating membrane thickness was 10 μm.

[0348] The manufacturing process of a secondary battery cell is as follows.

[0349] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, positive electrode binder polyvinylidene fluoride (PVDF), and positive electrode conductive agent carbon black are added to N-methylpyrrolidone (NMP) in a mass ratio of 97:2:1 and thoroughly mixed 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.

[0350] 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.

[0351] At 25°C, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7 to obtain a mixed solvent. LiPF6 and fluoroethylene carbonate (FEC) were then dissolved in this mixed solvent to obtain the electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of FEC was 3%, based on the mass of the electrolyte.

[0352] 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 a hard outer packaging, and the electrolyte prepared above is added. After processes such as encapsulation, standing, formation, and aging, a secondary battery cell is obtained.

[0353] Performance testing

[0354] (1) Thermal shrinkage rate test of the separator film

[0355] The heat shrinkage rate test of the release liner can be referenced in GB / T 36363-2018.

[0356] 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.

[0357] Set the temperature of the forced-air drying oven to 130℃. After the temperature reaches the set temperature and stabilizes for 60 minutes, place the A4 paper placed on the corrugated paper into the forced-air drying oven and start timing. After the set time (1 hour in this disclosure) is reached, measure the length and width of the isolation film, and mark the values ​​as a and b respectively.

[0358] 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.

[0359] (2) Cycle performance test of secondary battery cells

[0360] At 60℃, a single secondary battery cell is charged to 4.25V at a constant current of 1 / 3C, then charged to a current of 0.05C at a constant voltage of 4.25V, rested for 5 minutes, and then discharged to 2.8V at a constant current of 1 / 3C. The resulting discharge capacity is recorded as the initial capacity C0. The above charging and discharging steps are repeated, and the discharge capacity Cn of the single secondary battery cell after the nth cycle is recorded. The capacity retention rate of the single secondary battery cell after each cycle is Pn = (Cn / C0) × 100%. The capacity retention rate of the single secondary battery cell after 500 cycles can be used to reflect the difference in cycle performance of the single secondary battery cell.

[0361] Table 1

[0362] As can be seen from the above test results, the phenolic resin organic particles prepared in this embodiment have a low dissolution rate and can also improve the heat resistance of the separator and the high-temperature cycle performance of the secondary battery cell.

[0363] Next, the phenolic resin organic particles will be replaced with polymer particles containing triazine ring structural units.

[0364] Commercially available melamine-formaldehyde resin granules were cured in air at 260°C for 4 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules 2-1# containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.5:1.

[0365] Commercially available melamine-formaldehyde resin granules were cured in air at 240°C for 5 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules 2-2# containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.5:1.

[0366] Commercially available melamine-formaldehyde resin granules were cured in air at 285°C for 3.5 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules (2-3#) containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.5:1.

[0367] Commercially available melamine-formaldehyde resin granules were cured in air at 150°C for 4 hours, followed by crushing, milling, sieving, and demagnetization to obtain polymer granules D2-1# containing triazine ring structural units. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.5:1.

[0368] The organic particles 2-1# to 2-3# prepared above meet the following characteristics: no melting point, and no glass transition temperature T below 300℃. g .

[0369] Table 2

[0370] As can be seen from the above test results, the polymer particles containing triazine ring structural units prepared in this embodiment have a low dissolution rate and can also improve the heat resistance of the separator and the high-temperature cycling performance of the secondary battery cell.

[0371] Next, the phenolic resin organic particles will be replaced with cross-linked styrene organic particles.

[0372] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 31 g styrene, and 9 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water was added to a reactor, and the temperature was raised to 65 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 72 °C and the reaction was allowed to mature for 2.5 hours to obtain a cross-linked styrene-based organic particle emulsion 3-1#.

[0373] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 27.5 g styrene, and 12.5 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water was added to a reactor, and the temperature was raised to 65 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 72 °C and the reaction was allowed to mature for 2.5 hours to obtain a cross-linked styrene-based organic particle emulsion 3-2#.

[0374] 0.8 g sodium dodecyl sulfate, 80 mg sodium persulfate, 20 ml deionized water, 39.5 g styrene, and 0.5 g divinylbenzene were emulsified to obtain a pre-emulsion for later use. 140 g deionized water was added to a reactor, and the temperature was raised to 65 °C. Under nitrogen protection and stirring, the prepared pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 72 °C and the reaction was allowed to mature for 2.5 hours to obtain a cross-linked styrene-based organic particle emulsion, D3-1#.

[0375] The organic particles 3-1# to 3-2# ​​prepared above meet the following characteristics: no melting point, glass transition temperature T g Between 110℃ and 156℃.

[0376] Table 3

[0377] As can be seen from the above test results, the cross-linked styrene organic particles prepared in this embodiment have a low dissolution rate and can also improve the heat resistance of the separator and the high-temperature cycling performance of the secondary battery cell.

[0378] Next, the phenolic resin organic particles will be replaced with silicon-containing organic resin particles.

[0379] A pre-emulsion was prepared by emulsifying 0.1g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 51.6g 3-(acryloyloxy)propyltrimethoxysilane, 3g γ-methacryloyloxypropyltriisopropoxysilane, and 5.4g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 82°C and the reaction was allowed to mature for 1.4 hours to obtain the 4-1# emulsion containing silicon-containing organic resin particles.

[0380] A pre-emulsion was prepared by emulsifying 0.42 g sodium persulfate, 0.3 g sodium bicarbonate, 1.5 g sodium dodecyl sulfate, 30 g deionized water, 51.6 g 3-(acryloyloxy)propyltrimethoxysilane, 3 g γ-methacryloyloxypropyltriisopropoxysilane, and 5.4 g divinylbenzene. In a reactor, 210 g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 82°C and the reaction was allowed to mature for 1.4 hours to obtain the 4-2# emulsion containing silicon-containing organic resin particles.

[0381] A pre-emulsion was prepared by emulsifying 0.9g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 51.6g 3-(acryloyloxy)propyltrimethoxysilane, 3g γ-methacryloyloxypropyltriisopropoxysilane, and 5.4g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 82°C and the reaction was allowed to mature for 1.4 hours to obtain the 4-3# emulsion containing silicon-containing organic resin particles.

[0382] A pre-emulsion was prepared by emulsifying 1.5g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 51.6g 3-(acryloyloxy)propyltrimethoxysilane, 3g γ-methacryloyloxypropyltriisopropoxysilane, and 5.4g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 82°C and the reaction was allowed to mature for 1.4 hours to obtain the 4-4# emulsion containing silicon-containing organic resin particles.

[0383] A pre-emulsion was prepared by emulsifying 0.42g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 49g 3-(acryloyloxy)propyltrimethoxysilane, 3g γ-methacryloyloxypropyltriisopropoxysilane, and 8g divinylbenzene. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 82°C and the reaction was allowed to mature for 1.4 hours to obtain a silicone-containing organic resin particle emulsion (4-5#).

[0384] A pre-emulsion was prepared by emulsifying 0.42g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, and 60g 3-(acryloyloxy)propyltrimethoxysilane. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 82°C and the reaction was allowed to mature for 1.4 hours to obtain the silicon-containing organic resin particle D4-1# emulsion.

[0385] The organic particles 4-1# to 4-5# prepared above meet the following characteristics: the silicon-containing organic resin particles have a network structure with carbon-carbon bonds as the main chain, and the side chains contain silicon-oxygen structures. They have no melting point and no glass transition temperature T below 300℃. g .

[0386] Table 4

[0387] As can be seen from the above test results, the silicon-containing organic resin particles prepared in this embodiment have a low dissolution rate and can also improve the heat resistance of the separator and the high-temperature cycle performance of the secondary battery cell.

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

Claims

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

2. The secondary battery cell according to claim 1, wherein The dissolution rate of the organic particles in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 1.5%.

3. The secondary battery cell according to any one of claims 1-2, wherein, The true density of the organic particles is 1.0 g / cm 3 -2.0 g / cm 3 ; optionally 1.0 g / cm 3 -1.8 g / cm 3 ; and / or, The volume distribution particle size Dv50 of the organic particles is less than 1 μm, and is optionally 50 nm-820 nm.

4. The secondary battery cell according to any one of claims 1 to 3, wherein The organic particles are at least one of thermosetting resin polymers or crosslinked polymers.

5. The secondary battery cell according to any one of claims 1 to 4, wherein The organic particles are amorphous polymers.

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

7. The secondary battery cell according to any one of claims 1 to 6, wherein The organic particles include one or more of phenolic resin-based organic particles, polymer particles containing triazine ring structure units, crosslinked styrene-based organic particles, and silicon-containing organic resin particles.

8. The secondary battery cell according to claim 7, wherein, The phenolic resin-based organic particles are thermosetting resol polymers; and / or, The phenolic resin-based organic particles have no glass transition temperature below 300°C; and / or, The volume distribution particle size Dv50 of the phenolic resin-based organic particles is 180 nm-820 nm.

9. The secondary battery cell according to any one of claims 7-8, wherein, The polymer particles containing triazine ring structure units include a bridging structure connecting the triazine ring structure units; and / or, The polymer particles containing triazine ring structure units have no glass transition temperature below 300°C; and / or, The volume distribution particle size Dv50 of the polymer particles containing triazine ring structure units is 180 nm-820 nm.

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

11. The secondary battery cell according to any one of claims 7 to 10, wherein The polymer particles containing triazine ring structure units further have a substituent on the triazine ring structure units, and the substituent includes one or a combination of two or more of alkyl group, alkenyl group, phenyl group, cycloalkyl group, amine group, hydroxyl group, and halogen.

12. The secondary battery cell according to any one of claims 7-11, wherein, The polymer particles containing triazine ring structure units include at least one of melamine formaldehyde-based polymers and derivatives thereof, etherified melamine formaldehyde-based polymers and derivatives thereof, etherified melamine formaldehyde-polyol polymers and derivatives thereof, etherified melamine formaldehyde-polycarboxylic acid polymers and derivatives thereof, and etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof.

13. The secondary battery cell according to claim 12, wherein, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine-formaldehyde-oxamide polymer, a methyletherified melamine-formaldehyde-malonamide polymer, a methyletherified melamine-formaldehyde-isophthalimide polymer, a buthyletherified melamine-formaldehyde-oxamide polymer, a buthyletherified melamine-formaldehyde-malonamide polymer, a buthyletherified melamine-formaldehyde-isophthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine-formaldehyde-oxamide polymer, a methyletherified melamine-formaldehyde-malonamide polymer, a methyletherified melamine-formaldehyde-isophthalimide polymer, a buthyletherified melamine-formaldehyde-oxamide polymer, a buthyletherified melamine-formaldehyde-malonamide polymer, a buthyletherified melamine-formaldehyde-isophthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine-formaldehyde-oxamide polymer, a methyletherified melamine-formaldehyde-malonamide polymer, a methyletherified melamine-formaldehyde-isophthalimide polymer, a buthyletherified melamine-formaldehyde-oxamide polymer, a buthyletherified melamine-formaldehyde-malonamide polymer, a buthyletherified melamine-formaldehyde-isophthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine-formaldehyde-oxamide polymer, a methyletherified melamine-formaldehyde-malonamide polymer, a methyletherified melamine-formaldehyde-isophthalimide polymer, a buthyletherified melamine-formaldehyde-oxamide polymer, a buthyletherified melamine-formaldehyde-malonamide polymer, a buthyletherified melamine-formaldehyde-isophthalimide polymer; and / or, the etherified melamine-aldehyde-polyamine amide polymers and derivatives thereof include one or more of a methyletherified melamine-formaldehyde-oxamide polymer, a methyletherified melamine-formaldehyde-malonamide polymer, a methyletherified melamine-formaldehyde-isophthalimide polymer, a buthyletherified melamine-formaldehyde-oxamide polymer, a buthyletherified melamine-formaldehyde-malonamide polymer, a buthyletherified melamine-formaldehyde-isophthalimide polymer; and / or, 14. The secondary battery cell according to any one of claims 7-13, wherein the crosslinked styrene-based organic particles include a styrene or styrene derivative structural unit and a crosslinking structural unit; and / or, The crosslinked styrenic organic particles have a glass transition temperature Tg g of 110 °C to 156 °C; and / or, the crosslinked styrene-based organic particles have a volume distribution particle size Dv50 of 90 nm to 310 nm.

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

16. The secondary battery cell according to any one of claims 7 to 15, wherein The silicon-containing organic resin particles are silicon-containing organic crosslinking resin particles, and the silicon-containing organic resin particles contain a carbon-carbon bond and a siloxane structure; and / or, The silicon-containing organic resin particles have no glass transition temperature at 300°C or lower; and / or, The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 90 nm to 310 nm.

17. The secondary battery cell of any one of claims 7-16, wherein, The silicon-containing organic resin particles are silicon-containing organic crosslinking resin particles, and the silicon-containing organic resin particles are network structures formed with a carbon-carbon bond as a main chain, and a side chain containing a siloxane structure.

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

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

2.

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

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

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

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

24. The separator film according to claim 23, wherein, The true density of the organic particles is 1.0 g / cm 3 -2.0 g / cm 3 ; optionally 1.0 g / cm 3 -1.8 g / cm 3 ; and / or, The volume distribution particle size Dv50 of the organic particles is less than 1 μm, and is optionally 50 nm-820 nm.

25. The separator membrane of any one of claims 23-24, wherein, The organic particles are at least one of thermosetting resin polymers or crosslinked polymers.

26. The separator membrane according to any one of claims 23-25, wherein, The organic particles are amorphous polymers.

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

28. The separator membrane of any one of claims 23-27, wherein, The organic particles comprise one or more of phenol formaldehyde resin-based organic particles, polymer particles containing triazine ring structure units, crosslinked styrene-based organic particles, and silicon-containing organic resin particles.

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