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

Abstract

A separator, a secondary battery cell, a battery device, and an electric device. The secondary battery cell comprises a positive electrode sheet, a negative electrode sheet, and a separator. The separator is provided between the positive electrode sheet and the negative electrode sheet. The separator comprises a porous base film and a coating located on at least one side of the porous base film, wherein the coating comprises organic particles, with the cyclic voltammetry curve of the first cycle of the organic particles not having an oxidation peak within a voltage range of 2.50 V to 4.40 V. The secondary battery cell has good capacity performance characteristics under a high pressure.

Description

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

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 202410946641.X, filed on July 15, 2024, entitled “Separator, battery cell and power consuming device” and Chinese Patent Application No. 202411382998.6, filed on September 30, 2024, entitled “Separator, secondary battery cell, battery device, and power consuming device”, the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

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

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

[0005] The present disclosure provides a separator, a secondary battery cell, a battery device, and a power consuming device, which has good capacity release characteristics under high pressure.

[0006] In a first aspect, the present disclosure provides a secondary battery cell, comprising a positive electrode sheet, a negative electrode sheet, and a separator, the separator being arranged between the positive electrode sheet and the negative electrode sheet, the separator comprising a porous base film and a coating layer arranged on at least one side of the porous base film, the coating layer comprising organic particles, and a cyclic voltammogram of the organic particles in the first cycle does not have an oxidation peak in a voltage range of 2.50V to 4.40V.

[0007] The density of the organic particles is small, and the secondary battery cell using the same can have higher mass energy density. The cyclic voltammogram of the organic particles of the separator of the present disclosure in the first cycle does not have an oxidation peak in a voltage range of 2.50V to 4.40V, which indicates that the organic particles are stable in the voltage range of 2.50V to 4.40V. Therefore, the organic particles of the present disclosure have good electrochemical stability, can be applied to high-voltage secondary battery cells, improve the working voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity release characteristics under high pressure.

[0008] In some embodiments, the organic particle has no oxidation peak in a cyclic voltammogram of the first cycle in a voltage range of 2.50V to 4.50V.

[0009] In some embodiments, the organic particle is at least one of a thermosetting resin polymer or a crosslinked polymer.

[0010] In some embodiments, the organic particle is an amorphous polymer.

[0011] In some embodiments, the organic particle has a true density of 1.0g / cm 3 -2.0g / cm 3 ; optionally 1.0g / cm 3 -1.8g / cm 3 .

[0012] In some embodiments, the organic particle has a volume distribution particle size Dv50 of less than 1μm, optionally 50nm-840nm.

[0013] In some embodiments, the organic particle has no melting point.

[0014] The organic particle of the present disclosure has no melting point, indicating that the organic particle has good heat resistance and thermal stability, thereby better resisting thermal shrinkage of the porous base film, improving the heat resistance of the separator film, and improving the reliability of the secondary battery cell.

[0015] In some embodiments, the organic particle comprises one or more of a phenol-aldehyde resin-based organic particle, a polymer particle containing a triazine ring structural unit, a crosslinked styrene-based organic particle, and a silicon-containing organic resin particle.

[0016] In some embodiments, the phenol-aldehyde resin-based organic particle is a thermosetting resol polymer.

[0017] In some embodiments, the phenol-aldehyde resin-based organic particle has no glass transition temperature below 300℃.

[0018] In some embodiments, the phenol-aldehyde resin-based organic particle has a volume distribution particle size Dv50 of 200nm-840nm.

[0019] In some embodiments, the polymer particle containing a triazine ring structural unit comprises a bridging structure connecting the triazine ring structural units. Optionally, the bridging structure comprises one or a combination of two or more of an alkylene group, an alkylene ether group, an alkylene amine group, an ester group, and an amide group.

[0020] In some embodiments, the triazine ring structural unit of the polymer particles containing triazine ring structural units further has a substituent thereon, the substituent comprising a combination of one or more of alkyl, alkenyl, phenyl, cycloalkyl, amine, hydroxyl, halogen.

[0021] In some embodiments, the polymer particles containing triazine ring structural units comprise melamine formaldehyde polymers and derivatives thereof.

[0022] In some embodiments, the melamine formaldehyde polymers and derivatives thereof comprise one or more of melamine formaldehyde, phenylated melamine formaldehyde, melamine-phenylated melamine formaldehyde, melamine-(2,4-diamino-1,3,5-triazine) formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine) formaldehyde, trihydrazinyl-s-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde.

[0023] In some embodiments, the polymer particles containing triazine ring structural units have no glass transition temperature below 300 °C.

[0024] In some embodiments, the polymer particles containing triazine ring structural units have a volume distribution particle size Dv50 of 200 nm to 840 nm.

[0025] In some embodiments, the cross-linked styrene-based organic particles comprise styrene or styrene derivative structural units and cross-linking structural units.

[0026] In some embodiments, the styrene or styrene derivative structural units comprise one or more of styrene structural units, 1-methyl-1-styrene structural units, 4-methylstyrene structural units, 2-methylstyrene structural units, 2,4-dimethylstyrene structural units, 2,5-dimethylstyrene structural units.

[0027] In some embodiments, the crosslinking structural unit includes one or more of a divinylbenzene structural unit, an 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.

[0028] In some embodiments, the crosslinked styrene-based organic particles have a glass transition temperature Tg of 110°C to 154°C. g

[0029] In some embodiments, the crosslinked styrene-based organic particles have a volume distribution particle size Dv50 of 88 nm to 295 nm.

[0030] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles contain a carbon-carbon bond and a siloxane structure.

[0031] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles are a network structure formed with a carbon-carbon bond as a main chain, and a side chain containing a siloxane structure.

[0032] In some embodiments, the silicon-containing organic crosslinked resin particles include a crosslinking structural unit.

[0033] ​Optionally, the crosslinking structural unit comprises 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, a 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-trimethyladipic acid bis[2-ethylaziridine] structural unit, a 1,1-sebacic acid 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.

[0034] In some embodiments, the silicon-containing organic resin particles have no glass transition temperature below 300℃.

[0035] In some embodiments, the silicon-containing organic resin particles have a volume distribution particle size Dv50 of 88 nm to 295 nm.

[0036] 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 film is greater than or equal to 1.2.

[0037] In some embodiments, the coating further comprises a binder.

[0038] In some embodiments, the mass content of the organic particles in the coating is 50% to 99% based on the total mass of the coating.

[0039] In some embodiments, the thickness of the coating is 0.5 μm to 5 μm.

[0040] In some embodiments, the areal density of the coating is 0.45 g / m 2 - 5 g / m 2 .

[0041] In a second aspect, the present disclosure provides a battery device comprising a plurality of the secondary battery cells of the first aspect of the present disclosure.

[0042] In a third aspect, the present disclosure provides a power-consuming device comprising the secondary battery cell of the first aspect of the present disclosure or the battery device of the second aspect of the present disclosure.

[0043] In a fourth aspect, the present disclosure provides an isolation membrane, comprising a porous base membrane and a coating layer on at least one side of the porous base membrane, wherein the coating layer comprises organic particles, and a cyclic voltammogram of the organic particles in a first cycle has no oxidation peak in a voltage range of 2.50V to 4.40V.

[0044] In some embodiments, the organic particles are at least one of a thermosetting resin polymer or a cross-linked polymer.

[0045] In some embodiments, the organic particles are amorphous polymers.

[0046] In some embodiments, the organic particles have a true density of 1.0g / cm 3 -2.0g / cm 3 ; optionally 1.0g / cm 3 -1.8g / cm 3 .

[0047] In some embodiments, the organic particles have a volume distribution particle size Dv50 of less than 1μm, optionally 50nm-840nm.

[0048] In some embodiments, the organic particles have no melting point.

[0049] In some embodiments, the organic particles comprise one or more of phenol formaldehyde resin organic particles, polymer particles containing triazine ring structure units, cross-linked styrene organic particles, and silicon-containing organic resin particles. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required to be used in the embodiments of the present disclosure will be briefly introduced below. Obviously, the drawings described below are only some of the embodiments of the present disclosure, and other drawings can also be obtained according to the drawings without creative labor.

[0051] FIG. 1 shows a schematic diagram of a secondary battery cell according to some embodiments of the present disclosure.

[0052] FIG. 2 shows a schematic diagram of an electric device according to some embodiments of the present disclosure.

[0053] In the drawings, the drawings are not necessarily drawn according to the actual proportions. DETAILED DESCRIPTION

[0054] Hereinafter, embodiments of the separation film, secondary battery cell, battery device, and power using device of the present disclosure are specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there are cases where unnecessary detailed explanations are omitted. For example, there are cases where detailed explanations of matters that are already well known, repeated explanations of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following explanations are provided so that those skilled in the art can fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0055] The "ranges" disclosed in the present disclosure are defined in the form of lower and upper limits, and a given range is defined by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The ranges defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, i.e., any lower limit can be combined with any upper limit to form a range. For example, if the ranges 60-120 and 80-110 are listed for a particular parameter, it is understood that the ranges 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present disclosure, unless otherwise specified, a numerical range "a-b" represents a shorthand manner of describing the arbitrary real number combinations between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein, and "0-5" is just a shorthand notation for these numerical combinations. In addition, when it is stated that a certain parameter is an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0056] Unless otherwise specified, all embodiments and optional embodiments of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure content of the present disclosure.

[0057] Unless otherwise specified, all technical features and optional technical features of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure content of the present disclosure.

[0058] If not otherwise specified, all steps of the present disclosure can be performed in sequence or randomly, preferably in sequence. For example, the method comprises steps (a) and (b) means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method can further comprise step (c) means that step (c) can be added to the method in any sequence, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0059] If not otherwise specified, in the present disclosure, the terms "first", "second", etc. are used to distinguish different objects, rather than to describe a specific sequence or primary and secondary relationship.

[0060] In the present disclosure, the terms "a plurality of" and "a plurality of" refer to two or more.

[0061] In the description of the embodiments of the present disclosure, if not otherwise specified, the first feature is "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature can be "above", "over" and "on" the second feature, which can be that the first feature is directly above or obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature can be "below", "under" and "under" the second feature, which can be that the first feature is directly below or obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0062] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25℃.

[0063] The secondary battery cell mentioned in the embodiments of the present disclosure can realize the function of charging and discharging independently, and can continue to be used by activating the active material through charging after discharging. The secondary battery cell can be in the shape of a cylinder, a cuboid or other shapes, which are not limited in the embodiments of the present disclosure. As shown in FIG. 1, the secondary battery cell 5 is a cuboid structure as an example.

[0064] The secondary battery cell provided by the embodiments of the present disclosure can include but is not limited to lithium battery cells, sodium battery cells, such as lithium ion battery cells, sodium ion battery cells, lithium metal battery cells, sodium metal battery cells, etc.

[0065] Embodiments of the present disclosure provide a secondary battery cell including an electrode assembly. The electrode assembly can be in a jelly-roll structure or in a stacked structure, and the embodiments of the present disclosure are not limited thereto. The secondary battery cell further includes an outer package configured to enclose the electrode assembly. The outer package can be a hard case such as a hard plastic case, an aluminum case, a steel case, etc. The outer package can also be a soft package such as a pouch-type soft package. The soft package can be made of plastic such as one or more of an aluminum laminate, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0066] A battery apparatus as referred to in embodiments of the present disclosure can include one or more battery cell assemblies configured to provide voltage and capacity. The battery cell assembly can include a plurality of secondary battery cells connected in series, in parallel, or in a mixed connection through a busbar.

[0067] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of secondary battery cells.

[0068] As an example, the battery cell assembly can be a battery module formed by arranging and fixing a plurality of secondary battery cells into a single independent module. As an example, the battery module can be formed by bundling a plurality of secondary battery cells with a cable tie.

[0069] In some embodiments, the battery apparatus can be a battery pack including a case and one or more battery cell assemblies received in the case.

[0070] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be received in the case by fixing the battery module in the case.

[0071] As an example, the battery cell assembly can also be received in the case by directly fixing a plurality of secondary battery cells in the case.

[0072] As an example, the case can include a first case and a second case. The first case and the second case are coupled to each other such that an enclosed space is formed inside the case to receive the battery cell assembly. The enclosed space herein means covered or closed, which can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0073] As an example, the case can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are coupled to the frame, respectively, such that an enclosed space is formed inside the case to receive the battery cell assembly.

[0074] In some embodiments, the box can be part of a chassis structure of the vehicle. For example, portions of the box can be part of a floor of the vehicle, or portions of the box can be part of cross members and longitudinal members of the vehicle.

[0075] The technical solutions described in the embodiments of the present disclosure are applicable to various electric devices using secondary battery cells and battery devices, such as, but not limited to, mobile devices (such as mobile phones, tablets, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. The secondary battery cells and battery devices are used to store or provide electric energy.

[0076] FIG. 2 is a schematic diagram of an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0077] In the context of the present disclosure, the "organic particles" in the coating of the separator mainly play a role in improving heat resistance, and have little adhesion.

[0078] The separator is an important component for supporting the secondary battery cell to complete the electrochemical process of charging and discharging. Commonly used separators are mostly polyolefin materials, but such materials have a low glass transition temperature and will have a serious thermal shrinkage phenomenon after being heated. In order to improve the heat resistance of the separator, boehmite or alumina is commonly used as a heat-resistant filler and a binder to form a coating. Boehmite and alumina have a large density, and the mass of boehmite and alumina is greater than that of other materials under the same packing volume, thereby affecting the energy density of the secondary battery cell.

[0079] The embodiments of the present disclosure provide a separator, which can enable the secondary battery cell using the same to have good capacity performance under high pressure.

[0080] The separator provided by the embodiments of the present disclosure includes a porous base film and a coating on at least one side of the porous base film, and the coating includes organic particles and a binder. The cyclic voltammetry curve of the organic particles in the first cycle has no oxidation peak in the voltage range of 2.50V to 4.40V.

[0081] The porous base film and the coating both have a pore structure, so that the separator has good air permeability and facilitates the passage of ions. The organic particles in the coating are connected to each other and fixed by the binder, and the gap between the organic particles can form a pore structure.

[0082] The organic particles have a small density, and the secondary battery cell using the same can have a higher mass energy density. The energy density of the secondary battery cell can be improved by replacing boehmite and alumina with the organic particles having a smaller density, but the electrochemical stability of the conventional organic particles is generally poor. The cyclic voltammogram of the organic particles of the separator of the present disclosure for the first cycle has no oxidation peak in the voltage range of 2.50V to 4.40V, which indicates that the organic particles are stable in the voltage range of 2.50V to 4.40V. Therefore, the organic particles of the present disclosure have good electrochemical stability, can be applied to high-voltage secondary battery cells, improve the operating voltage and energy density of the secondary battery cell, and also enable the secondary battery cell to have good capacity release characteristics at high voltage.

[0083] In some embodiments, the cyclic voltammogram of the organic particles for the first cycle has no oxidation peak in the voltage range of 2.50V to 4.45V.

[0084] In some embodiments, the cyclic voltammogram of the organic particles for the first cycle has no oxidation peak in the voltage range of 2.50V to 4.50V.

[0085] The oxidation peak potential of the cyclic voltammogram of the organic particles can be tested as follows: the organic particles, the binder polyacrylate, and the conductive agent conductive carbon black are dissolved in water in a solid content mass ratio of 64:7:29 to prepare a slurry, the slurry is coated on an aluminum foil as a positive electrode, a lithium foil is used as a negative electrode, and a coin cell is assembled; the coin cell is subjected to cyclic voltammetry (CV) test, the scan rate is 0.10mV / s, the voltage range is 2.50V-5.00V, and the cycle is 3 cycles, and the voltage corresponding to the peak point of the cyclic voltammogram for the first cycle is taken as the oxidation peak potential. The electrolyte salt of the electrolyte used for testing is LiPF6, and the concentration is 1mol / L. The solvent of the electrolyte is obtained by mixing ethylene carbonate (EC) and methyl ethyl carbonate (EMC) in a volume ratio of 3:7.

[0086] In some embodiments, the true density of the organic particles can be 1.0g / cm 3 -2.0g / cm 3 . Alternatively, the true density of the organic particles can be 1.0g / cm 3 -1.8g / cm 3 .

[0087] At present, the true density of inorganic particles such as boehmite and alumina is generally 2.5g / cm 3 -3.5g / cm 3 . The true density of the organic particles of the present disclosure is small, so that the secondary battery cell using the separator of the present disclosure can have a higher mass energy density.

[0088] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, optionally 50 nm-840 nm, 88 nm-840 nm.

[0089] The organic particles of the present disclosure are neither soluble in water nor in organic solvents such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), chloroform at 25°C, i.e. insoluble in the mobile phase tested by gel permeation chromatography, nor can the molecular weight of the organic particles be tested by gel permeation chromatography.

[0090] The organic particles of the present disclosure are at least one of a thermosetting resin polymer or a crosslinked polymer.

[0091] The thermosetting resin polymer refers to a polymer product that hardens irreversibly upon curing, and once cured, does not soften or melt upon heating.

[0092] The crosslinked polymer refers to a polymer product obtained when crosslinking bonds are formed between monomer units.

[0093] The organic particles of the present disclosure are amorphous polymers.

[0094] In some embodiments, the organic particles have no melting point.

[0095] The organic particles of the present disclosure have no melting point, indicating that the organic particles have good heat resistance and thermal stability, and thus can better resist thermal shrinkage of the porous base film, improve the heat resistance of the isolation film, and improve the reliability of the secondary battery cell.

[0096] The melting point can be tested according to the following method: take an appropriate amount of sample (e.g. 5 mg-15 mg) and place it in a differential scanning calorimeter (DSC) crucible, shake it flat, and cover it with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60 mL / min, protective gas 20 mL / min; program settings: increase the temperature from 25°C to 200°C at a rate of 10°C / min, hold for 5 min to eliminate thermal history, then decrease the temperature from 200°C to -40°C at a rate of 10°C / min, and then increase the temperature to 300°C at a rate of 10°C / min. Whether the organic particles have a melting point below 300°C is determined by the DSC curve.

[0097] The organic particles having no melting point means that the DSC curve of the organic particles has no melting peak.

[0098] In some embodiments, the organic particles can include one or more of a phenolic resin-based organic particle, a polymer particle containing a triazine ring structure unit, a crosslinked styrene-based organic particle, and a silicon-containing organic resin particle.

[0099] [Phenolic resin-based organic particles]

[0100] In some embodiments, the phenolic resin-based organic particles are thermosetting resin polymers.

[0101] In some embodiments, the phenolic resin-based organic particles are thermosetting resol polymers.

[0102] The raw material of the phenolic resin-based organic particles can include phenolic compounds and aldehyde compounds. In some embodiments, the phenolic compounds can include one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cardanol. In some embodiments, the aldehyde compounds can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0103] In some embodiments, the phenolic resin-based organic particles have no glass transition temperature below 300°C.

[0104] The phenolic resin-based organic particles have no glass transition temperature below 300°C, indicating that the organic particles have good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the porous base film, improving the heat resistance of the separator film, and improving the reliability of the secondary battery cell.

[0105] In some embodiments, the volume distribution particle size Dv50 of the phenolic resin-based organic particles can be 200 nm-840 nm.

[0106] The volume distribution particle size Dv50 of the polymer particles of the phenolic resin-based organic particles is within the above range, which is conducive to the separator film having good heat resistance and air permeability.

[0107] Resol-based materials generally have poor electrochemical stability and cannot meet the electrochemical stability requirements of the separator film. Based on this, the present disclosure provides a phenolic resin-based organic particle, which has no oxidation peak in the cyclic voltammetry curve of the first cycle in the voltage range of 2.50V to 4.40V. The present disclosure also provides a method for preparing the phenolic resin-based organic particle.

[0108] In some embodiments, the method for preparing the phenolic resin-based organic particle includes the following steps: providing a resol-based material; curing the resol-based material at a first temperature in an oxygen-containing atmosphere for a first time, then curing the resol-based material at a second temperature in an oxygen-containing atmosphere for a second time, and then crushing to obtain the phenolic resin-based organic particle. The first temperature is 100°C-170°C, and the second temperature is 220°C-290°C.

[0109] The phenolic resin organic particles with high electrochemical stability are obtained by segmental curing of the resol phenolic resin material. First, the resol phenolic resin material is cured at 100-170°C. In this process, the resol phenolic resin material gradually cures, and small molecular groups and easily oxidizable groups in the resol phenolic resin material begin to eliminate. Then, the resol phenolic resin material is cured again at 220-290°C. In this process, the resol phenolic resin material continues to undergo crosslinking and curing reactions, and is more fully cured. Further, the first-stage curing and the second-stage curing are performed in an oxygen-containing atmosphere. Curing in an oxygen-containing atmosphere can cause the easily oxidizable groups of the resol phenolic resin material to be oxidized in advance. At this time, the phenol structure is oxidized to a benzoquinone structure, and the benzoquinone structure is not easily oxidized. Thus, the phenolic resin organic particles with high electrochemical stability can be obtained.

[0110] The phenolic resin organic particles prepared by the present disclosure are thermosetting resol polymers.

[0111] In some embodiments, the oxygen-containing atmosphere can include oxygen and an inert gas. The volume fraction of oxygen in the oxygen-containing atmosphere can be 5%-50%. Alternatively, the inert gas can include, but is not limited to, one or more of nitrogen, argon, and helium.

[0112] Alternatively, the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%.

[0113] More alternatively, the oxygen-containing atmosphere can be an air atmosphere. Thus, the cost can also be reduced.

[0114] The first temperature is 100-170°C, for example, can be 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, or a range consisting of any of the above values.

[0115] Alternatively, the first temperature can be 110-170°C, 110-160°C, 110-150°C, 120-170°C, 120-160°C, 120-150°C.

[0116] The first temperature in the above range can make the curing of the resol phenolic resin material in the first stage more uniform and sufficient. Thus, the phenolic resin organic particles with higher electrochemical stability can be obtained.

[0117] In some embodiments, the first time can be 2-4h, for example, can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, or a range consisting of any of the above values.

[0118] The first temperature within the above range can make the curing of the resol resin-based material in the first stage more uniform and sufficient, so that the phenolic resin-based organic particles with higher electrochemical stability can be obtained.

[0119] The second temperature can be 220-290°C, for example, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, or a range consisting of any of the above values.

[0120] Alternatively, the second temperature can be 220-280°C, 220-270°C.

[0121] The second temperature within the above range can make the curing of the phenolic resin-based organic particles more sufficient and the electrochemical stability higher while avoiding the denaturation (such as degradation) of the phenolic resin-based organic particles.

[0122] In some embodiments, the second time can be 2-6h, for example, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, or a range consisting of any of the above values.

[0123] The second time within the above range can make the curing of the phenolic resin-based organic particles more sufficient and the electrochemical stability higher.

[0124] In some embodiments, the method for preparing the phenolic resin-based organic particles further comprises the steps of sieving and removing magnetism after the crushing treatment.

[0125] In some embodiments, the resol resin-based material can have a free phenol content of 5% or less, optionally 4% or less, 3% or less, 2% or less.

[0126] In some embodiments, the resol resin-based material can have a free aldehyde content of 5% or less, optionally 4% or less, 3% or less, 2% or less.

[0127] The low content of free phenol and free aldehyde helps to obtain the phenolic resin-based organic particles with higher electrochemical stability.

[0128] The resol resin-based material can be commercially available or synthesized according to the methods known in the art. In some embodiments, the method for preparing the resol resin-based material comprises the step of reacting a phenolic compound and an aldehyde compound under the catalysis of an alkaline substance to obtain the resol resin-based material.

[0129] Optionally, the molar ratio of the phenolic hydroxyl group of the phenolic compound to the aldehyde group of the aldehyde compound can be 1:1.1 to 1:1.5.

[0130] Optionally, the basic substance can include one or more of ammonia, NaOH, Na2CO3.

[0131] Optionally, the phenolic compound can include one or more of phenol, p-dihydroxybenzene, m-dihydroxybenzene, o-dihydroxybenzene, cresol, cardanol.

[0132] Optionally, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propyl aldehyde, n-butyl aldehyde, glyoxal, and furfural.

[0133] [Polymer particles containing triazine ring structural units]

[0134] The polymer particles containing triazine ring structural units of the present disclosure further include a bridging structure connecting the triazine ring structural units.

[0135] The polymer particles containing triazine ring structural units contain a plurality of triazine ring structural units in the molecular structure, and the bridging structure refers to a group connecting the triazine ring structural units, each bridging structure being the same or different.

[0136] Optionally, the bridging structure can include one or a combination of two or more of alkylene, alkylene ether, alkylene amine.

[0137] In some embodiments, the triazine ring structural units of the polymer particles containing triazine ring structural units can further have a substituent, and the substituent can include a combination of one or more of alkyl, alkenyl, phenyl, cycloalkyl, amine, hydroxyl, halogen.

[0138] In some embodiments, the polymer particles containing triazine ring structural units can include melamine aldehyde-based polymers and derivatives thereof.

[0139] In some embodiments, the melamine aldehyde-based polymers and derivatives thereof can include melamine formaldehyde polymers and derivatives thereof.

[0140] Optionally, the melamine aldehyde-based polymers and derivatives thereof can include one or more of melamine formaldehyde, benzotriazine formaldehyde, melamine-benzotriazine formaldehyde, melamine-(2,4-diamino-1,3,5-triazine) formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine) formaldehyde, trihydrazinotriazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde.

[0141] In some embodiments, the polymer particles containing triazine ring structural units have no glass transition temperature below 300°C.

[0142] The polymer particles containing triazine ring structural units have no glass transition temperature below 300°C, which indicates that the organic particles have good heat resistance and thermal stability, and thus can better resist the thermal shrinkage of the porous base film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0143] In some embodiments, the polymer particles containing triazine ring structural units have a volume distribution particle size Dv50 of 200 nm-840 nm.

[0144] The polymer particles containing triazine ring structural units have a volume distribution particle size Dv50 in the above range, which is beneficial to the separator film having good heat resistance and air permeability.

[0145] The present disclosure provides a polymer particle containing triazine ring structural units, which has no oxidation peak in the cyclic voltammetry curve of the first cycle in the voltage range of 2.50 V to 4.40 V. The present disclosure also provides a method for preparing the polymer particle containing triazine ring structural units.

[0146] In some embodiments, the method for preparing the polymer particles containing triazine ring structural units comprises the following steps: providing a precursor containing triazine ring structure; heating and curing the precursor containing triazine ring structure in an oxygen-containing atmosphere, and then crushing to obtain the polymer particles containing triazine ring structural units, and the heating and curing temperature is 220°C-290°C. After the heating and curing of the precursor containing triazine ring structure, a bridging structure is formed between the triazine ring structural units.

[0147] The heating and curing temperature is 220°C-290°C, for example, it can be 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 290°C, or a range consisting of any of the above values.

[0148] Heating and curing the precursor containing triazine ring structure at 220°C-290°C can obtain the polymer particles containing triazine ring structural units with high electrochemical stability.

[0149] Optionally, the heating and curing temperature can be 225°C-290°C, 230°C-290°C, 225°C-280°C, or 230°C-280°C.

[0150] In some embodiments, the time for heat curing can be 3h-6h, for example, 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 a range consisting of any of the aforementioned values.

[0151] The time for heat curing within the aforementioned range is conducive to the precursor containing triazine ring structure to form polymer particles containing triazine ring structure units with higher electrochemical stability.

[0152] In some embodiments, the oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the inert gas can include one or more of nitrogen, argon, helium, but not limited to. In some embodiments, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5%-50%. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More optionally, the oxygen-containing atmosphere can be an air atmosphere.

[0153] In some embodiments, the polymer particles containing triazine ring structure units further include the steps of sieving treatment and magnetic removal treatment after the crushing treatment.

[0154] In some embodiments, the precursor containing triazine ring structure can include melamine formaldehyde resin. The melamine formaldehyde resin can be obtained by reacting an aldehyde compound with an amine-substituted triazine compound, and the amine-substituted triazine compound can include melamine and / or melamine derivatives.

[0155] Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 1.75:1-3:1, for example, can be 1.75:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, or a range consisting of any of the aforementioned values.

[0156] More optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 2:1-3:1, 2.1:1-3:1, 2.2:1-3:1, 2.3:1-3:1, 2.4:1-3:1.

[0157] In some embodiments, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propyl aldehyde, n-butyl aldehyde, glyoxal, and furfural.

[0158] In some embodiments, the amine-substituted triazine compound can include one or more of the following compounds of the general formula, R1, R2are each independently selected from any one of H, -NH2, C1-C8 alkyl, R3is selected from any one of H, -NH2, -NHR4, C1-C8 alkyl, C2-C8 alkenyl, phenyl, C7-C12 alkylphenyl, C7-C12 phenylalkyl, C5-C8 cycloalkyl, R4is selected from any one of -NH2, C1-C8 alkyl. Alternatively, R3is selected from -NH2or -NHR4.

[0159] Alternatively, the amine-substituted triazine compound can include one or more of melamine, benzoguanamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazinotriazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 6-ethyl-1,3,5-triazine-2,4-diamine, 6-isopropyl-1,3,5-triazine-2,4-diamine, 6-pentyl-2,4-diamino-1,3,5-triazine, 6-heptyl-2,4-diamino-triazine, 2-vinyl-4,6-diamino-1,3,5-triazine, 2,4-diamino-6-(4-methylphenyl)-1,3,5-triazine, 6-cyclohexyl-1,3,5-triazine-2,4-diamine, 6-(3-methylphenyl)-1,3,5-triazine-2,4-diamine, 6-o-tolyl-1,3,5-triazine-2,4-diamine, 6-(2,4-dimethylphenyl)-1,3,5-triazine-2,4-diamine, 6-phenylmethyl-1,3,5-triazine-2,4-diamine, (diamino-1,3,5-triazin-2-yl)methanol, 2-chloro-4,6-diamino-1,3,5-triazine.

[0160] More alternatively, the amine-substituted triazine compound can include one or more of melamine, benzoguanamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazinotriazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine.

[0161] [Crosslinked styrene-based organic particles]

[0162] The crosslinked styrene-based organic particles include a styrene or styrene derivative structural unit and a crosslinking structural unit. The crosslinking structural unit of the crosslinked styrene-based organic particles refers to a structural unit for linking the styrene or styrene derivative structural unit.

[0163] In some embodiments, the styrene or styrene derivative structural units can include one or more of styrene structural units, 1-methyl-1-styrene structural units, 4-methylstyrene structural units, 2-methylstyrene structural units, 2,4-dimethylstyrene structural units, 2,5-dimethylstyrene structural units.

[0164] In some embodiments, the crosslinking structural units can include one or more of divinylbenzene structural units, ethylene glycol dimethacrylate structural units, pentaerythritol tetraacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, tripropylene glycol diacrylate structural units, N,N-methylenebisacrylamide structural units, N,N'-vinylbisacrylamide structural units, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural units, trisallyl isocyanurate structural units.

[0165] In some embodiments, the glass transition temperature T g may be 110°C to 154°C.

[0166] The glass transition temperature T g of the crosslinked styrene-based organic particles is high, and the particles have good heat resistance and thermal stability, thereby being able to better resist thermal shrinkage of the porous base film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0167] In some embodiments, the volume distribution particle size Dv50 of the crosslinked styrene-based organic particles can be 88nm-295nm.

[0168] The volume distribution particle size Dv50 of the crosslinked styrene-based organic particles is within the above range, which is conducive to the separator film having good heat resistance and air permeability.

[0169] The present disclosure provides a crosslinked styrene-based organic particle, a cyclic voltammogram of which has no oxidation peak in a voltage range of 2.50V to 4.40V in the first cycle. The present disclosure also provides a method for preparing the crosslinked styrene-based organic particle.

[0170] In some embodiments, the method for preparing the crosslinked styrene-based organic particles comprises the following steps: providing a pre-emulsion comprising monomers, a crosslinking agent, an emulsifier, an initiator, and water, performing an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain the crosslinked styrene-based organic particles; the monomers comprise one or more of styrene and derivatives thereof; the maturation temperature of the emulsion polymerization reaction is 80-92°C, and the maturation time of the emulsion polymerization reaction is 1-4h.

[0171] The maturation temperature of the emulsion polymerization reaction is 80-92°C, for example, it can be 80°C, 81°C, 82°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, 91°C, 92°C, or a range consisting of any of the above values.

[0172] The maturation time of the emulsion polymerization reaction is 1-4h, 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 a range consisting of any of the above values.

[0173] The maturation temperature and the maturation time of the emulsion polymerization reaction are within the above ranges, and the crosslinked styrene-based organic particles with high electrochemical stability can be obtained.

[0174] In some embodiments, the emulsion polymerization reaction can comprise the following steps: under a first heating temperature, inert gas protection, and stirring conditions, the pre-emulsion is added dropwise into a reactor containing water, and after a first time, the temperature is raised to a maturation temperature for a maturation reaction to obtain the crosslinked styrene-based organic particles.

[0175] Optionally, the first heating temperature can be 55-70°C.

[0176] Optionally, the first time can be 3-7h.

[0177] In some embodiments, the mass fraction of the crosslinking agent can be 4-28%, for example, it can be 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 22%, 24%, 26%, 28%, or a range consisting of any of the above values, based on 100% of the total mass of the monomers and the crosslinking agent.

[0178] The mass fraction of the crosslinking agent is within the above range, which can improve the electrochemical stability and heat resistance of the crosslinked styrene-based organic particles.

[0179] Optionally, the mass fraction of the crosslinking agent can be 6%-28%, 8%-28%, 10%-28%, 4%-26%, 6%-26%, 8%-26%, 10%-26%.

[0180] In some embodiments, the solid content of the emulsion polymerization reaction system can be 10%-25%, for example, can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, or a range consisting of any of the above values. The solid content of the emulsion polymerization reaction system refers to the mass fraction of monomers and crosslinking agents in the reaction system.

[0181] The solid content of the emulsion polymerization reaction system in the above range can improve the conversion rate of monomers and can improve the electrochemical stability of the crosslinked styrene-based organic particles.

[0182] Optionally, the solid content of the emulsion polymerization reaction system can be 12%-25%, 14%-25%, 16%-25%.

[0183] In some embodiments, the monomers can include one or more of styrene, 1-methyl-1-phenylethylene, 4-methylstyrene, 2-methylstyrene, 2,4-dimethylstyrene, and 2,5-dimethylstyrene.

[0184] The crosslinking agent forms a crosslinked structure unit of the crosslinked styrene-based organic particles after polymerization with the monomers. In some embodiments, the crosslinking agent can include one or more of divinylbenzene, ethylene glycol dimethacrylate, pentaerythritol tetraacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, N,N-methylenebisacrylamide, N,N'-vinylbisacrylamide, 1,3,5-triacryloylhexahydro-1,3,5-triazine, and triallyl isocyanurate.

[0185] Optionally, the crosslinking agent can include one or more of divinylbenzene, N,N-methylenebisacrylamide, and N,N'-vinylbisacrylamide.

[0186] In some embodiments, the emulsifier can include, but is not limited to, one or more of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, fatty acid sorbitan, polysorbate, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol, polyoxyethylene ether emulsifier, cellulose and its derivatives.

[0187] Optionally, the polyoxyethylene ether emulsifier can include OP type emulsifiers such as OP-4, OP-7, OP-10, OP-15, OP-20, and the like.

[0188] In some embodiments, the mass fraction of the emulsifier can be 0.1%-3%, based on 100% of the total mass of the monomer and the crosslinking agent.

[0189] In some embodiments, the initiator can include, but is not limited to, one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisdimethylamid hydrochloride, azobisdimethylimidazoline hydrochloride, and azobisdiisopropylimidazoline.

[0190] In some embodiments, the mass fraction of the initiator can be 0.16%-3%, optionally 0.2%-2%, 0.25%-2%, based on 100% of the total mass of the monomer and the crosslinking agent.

[0191] In some embodiments, the method for preparing the crosslinked styrene-based organic particles further includes a step of removing the magnetic treatment after the emulsion polymerization reaction is completed.

[0192] [Silicon-containing organic resin particles]

[0193] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles contain carbon-carbon bonds and siloxane structures.

[0194] Optionally, the silicon-containing organic resin particles are network structures formed with carbon-carbon bonds as the main chain, and the side chains contain siloxane structures.

[0195] Optionally, the silicon-containing organic resin particles are network structures formed with carbon-carbon bonds as the main chain, and the side chains contain siloxane structures and benzene ring structures.

[0196] In some embodiments, the silicon-containing organic crosslinked resin particles include crosslinking structure units. The crosslinking structure units of the silicon-containing organic crosslinked resin particles refer to silicon-free structure units used to connect the silicon-containing structure units.

[0197] Optionally, the crosslinking structural unit can include 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, a 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-trimethyl adipic acid bis[2-ethylaziridine] structural unit, a 1,1-sebacic acid 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.

[0198] The raw material of the silicon-containing organic resin particles can include a monomer and a crosslinking agent, the monomer can include a silane coupling agent containing an alkenyl group and / or an acryloyloxy group. The crosslinking agent forms a crosslinking structural unit of the silicon-containing organic crosslinking resin particles after polymerization with the monomer. In some embodiments, the crosslinking agent can be a multifunctional crosslinking agent. Optionally, the crosslinking agent can include one or more of divinylbenzene, diethylene glycol divinyl ether, triethylene glycol divinyl ether, maleic acid diallyl ester, 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-trimethyl adipic acid bis[2-ethylaziridine], 1,1-sebacic acid bis[2-methylaziridine], 1,1-(1,3-phenylenedicarbonyl) bis[2-methylaziridine], trimethylolpropane tris(2-methyl-1-aziridinyl propionate), trimethylolpropane-tris[3-(2-methylaziridinyl) propionate], pentaerythritol tris(3-aziridinyl) propionate.

[0199] In some embodiments, the silicon-containing organic resin particles have no glass transition temperature below 300°C.

[0200] The silicon-containing organic resin particles have no glass transition temperature below 300°C, which indicates that the silicon-containing organic particles have good heat resistance and thermal stability, and thus can better resist thermal shrinkage of the porous base film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0201] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles can be 88 nm-295 nm.

[0202] The volume distribution particle size Dv50 of the silicon-containing organic resin particles in the above range is beneficial to the isolation film having good heat resistance and air permeability.

[0203] The present disclosure provides a silicon-containing organic resin particle, a cyclic voltammogram of which in the first cycle has no oxidation peak in a voltage range of 2.50 V to 4.40 V. The present disclosure also provides a method for preparing the silicon-containing organic resin particle.

[0204] In some embodiments, the method for preparing the silicon-containing organic resin particles comprises the following steps: providing a pre-emulsion comprising monomers, a crosslinking agent, an emulsifier, an initiator, and water, and performing an emulsion polymerization reaction under the conditions of heating, inert gas protection, and stirring to obtain the silicon-containing organic resin particles. The monomers comprise a silane coupling agent containing an alkenyl group and / or an acryloyloxy group. The mass fraction of the crosslinking agent is 3%-15% based on the total mass of the monomers and the crosslinking agent.

[0205] The monomers comprise a silane coupling agent containing an alkenyl group and / or an acryloyloxy group, so that free radicals are generated between the monomers to initiate a crosslinking reaction, and the monomers also crosslink with the crosslinking agent. Therefore, the silicon-containing organic resin particles with a three-dimensional network structure can be formed using the monomers and the crosslinking agent of the present disclosure, which are not easy to soften or deform at high temperatures and have high heat resistance and electrochemical stability.

[0206] The mass fraction of the crosslinking agent is 3%-15% based on the total mass of the monomers and the crosslinking agent, for example, 3%, 4%, 5%, 6%, 7%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, or a range consisting of any of the above values.

[0207] The mass fraction of the crosslinking agent in the above range can obtain silicon-containing organic resin particles with high electrochemical stability and good heat resistance.

[0208] Alternatively, the mass fraction of the crosslinking agent can be 8%-14%, 8%-13%, 8%-12%, 9%-14%, 9%-13%, 9%-12%.

[0209] The crosslinking agent and the monomers are polymerized to form a crosslinking structure unit of the silicon-containing organic crosslinking resin particles.

[0210] In some embodiments, the crosslinking agent can be a multifunctional crosslinking agent.

[0211] Optionally, the crosslinking agent can include one or more of 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-trimethylhexanedioic acid bis[2- ethylaziridine], 1,1-nonanedioic acid bis[2-methylaziridine], 1,1-(1,3- phenylenedicarbonyl)bis[2-methylaziridine], trimethylolpropane tris(2-methyl-1- aziridinylpropionate), trimethylolpropane-tris[3-(2-methylaziridinyl)propionate], pentaerythritol tris(3-aziridinyl)propionate.

[0212] In some embodiments, the monomer can include a vinyl silane coupling agent and / or an acryloxy silane coupling agent.

[0213] Optionally, the monomer can include one or more of gamma-methacryloxypropyl tris(trimethylsiloxy)silane, (3-acryloyloxypropyl)tris(trimethylsiloxy)silane, 3- methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3- methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, gamma- methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3- methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-t-butoxyvinylsilane, vinyltris(p-methoxyethoxy)silane, ethylene tris[(1-methylethenyl)oxy]silane, vinyltris-t-butylperoxysilane, 3- methacryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, methacryloxypropyl dimethylmethoxysilane, (3-acryloxy)dimethylmethoxysilane, 3-methacryloxypropyl dimethylethoxysilane, diethylmethylvinylsilane, vinyl dimethylethoxysilane, methylethylvinylsilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylethylvinylsilane, 3-(methacryloxy)propylmethyldiethoxysilane.

[0214] In some embodiments, the monomer can include a first monomer and a second monomer.

[0215] The first monomer can include one or more of gamma-methacryloxypropyl tris(trimethylsiloxy)silane, (3-acryloyloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, gamma-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-t-butoxyvinylsilane, vinyltris(beta-methoxyethoxy)silane, ethylene tris[(l-methylethenyl)oxy]silane, vinyltris-t-butylperoxysilane.

[0216] The second monomer can include one or more of 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, methacryloxypropyldimethylmethoxysilane, (3-acryloxy)dimethylmethoxysilane, 3-methacryloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyl dimethyl ethoxysilane, methyl vinyl diethoxysilane, vinyl methyl dimethoxysilane, vinyl methyl diethoxysilane, methyl vinyl dimethoxysilane, 3-(methacryloxy)propylmethyldiethoxysilane.

[0217] The first monomer and the second monomer are different in activity, and by combining the two and reacting with the crosslinking agent, a silicon-containing organic resin particle having a narrow particle size distribution can be obtained.

[0218] In some embodiments, the emulsifier can include, but is not limited to, one or more of an alkyl sulfate, an alkyl sulfonate, a Tween emulsifier, a fatty alcohol polyoxyethylene ether, a fatty alcohol polyoxypropylene ether, a ceteareth, an oleyl ether. Optionally, the emulsifier includes one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, Tween 20, Tween 40, laureth-7, laureth-9, laureth-10, oleyl ether-10.

[0219] In some embodiments, the initiator can include, but is not limited to, one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyronitrile, azobisisobutyramidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobisisopropylimidazoline.

[0220] In some embodiments, the heating temperature of the maturation stage of the emulsion polymerization reaction can be 75-85°C, for example, can be 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, or a range consisting of any of the aforementioned values.

[0221] In some embodiments, the heating time of the maturation stage of the emulsion polymerization reaction can be 1-4h, for example, can be 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, or a range consisting of any of the aforementioned values.

[0222] In some embodiments, the emulsion polymerization reaction can comprise the following steps: dropping the pre-emulsion into the reactor containing water under the second heating temperature, inert gas protection and stirring conditions, and after reacting for a second time, increasing the temperature to the heating temperature of the maturation stage to carry out the maturation reaction, to obtain the silicon-containing organic resin particles.

[0223] Optionally, the second heating temperature can be 55-70°C.

[0224] Optionally, the second time can be 3-8h.

[0225] In some embodiments, the pre-emulsion can further comprise a pH adjuster. Optionally, the pH adjuster can comprise one or more of, but not limited to, sodium bicarbonate, sodium hydroxide, ammonia, etc.

[0226] In some embodiments, the method for preparing the silicon-containing organic resin particles can further comprise the step of magnetic removal after the emulsion polymerization reaction is completed.

[0227] In some embodiments, the mass content of the organic particles in the coating can be 50-99% based on the total mass of the coating.

[0228] Optionally, the mass content of the 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%, 88-95%.

[0229] In some embodiments, the binder in the coating can comprise one or more of, but not limited to, polyacrylate-based binders, nitrile rubber-based binders, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0230] In some embodiments, the coating layer can further include a dispersant, such as can include but is not limited to a polyacrylic dispersant or a carboxymethyl cellulose dispersant. As an example, the dispersant can include but is not limited to one or more of sodium carboxymethyl cellulose, sodium polyacrylate, ammonium polyacrylate.

[0231] In some embodiments, the separator film can further include polymeric binder particles. The "polymeric binder particles" function to improve the adhesion of the separator film to the pole piece in the separator film, which has substantially no high-temperature resistance.

[0232] In some embodiments, the polymeric binder particles can be embedded in the organic particles and form protrusions on the surface of the coating layer.

[0233] In other embodiments, the coating layer of the separator film includes a heat-resistant layer disposed on the porous base film and a bonding layer disposed on at least a portion of the surface of the heat-resistant layer away from the porous base film, the organic particles are disposed in the heat-resistant layer, and the polymeric binder particles are disposed in the bonding layer.

[0234] In yet other embodiments, the coating layer of the separator film includes a heat-resistant layer disposed on one side of the porous base film and a bonding layer disposed on at least a portion of the surface of the other side of the porous base film, the organic particles are disposed in the heat-resistant layer, and the polymeric binder particles are disposed in the bonding layer.

[0235] In some embodiments, the average particle size of the polymeric binder particles can be 6 μm-18 μm.

[0236] The average particle size of the particles to be measured can be tested according to the following method: using a scanning electron microscope, referring to JY / T 010-1996, obtaining a SEM image of the separator film, randomly selecting a test sample of 50 mm x 100 mm in length x width on the separator film, randomly selecting a plurality of test areas (e.g., 5) in the test sample, and reading the particle size of the particles to be measured in each test area under a certain magnification (e.g., 500x or more); counting the number and particle size values of the particles to be measured in each test area, taking the arithmetic mean of the particle sizes of all the particles to be measured in each test area as the average particle size of the particles to be measured. In order to ensure the accuracy of the test results, a plurality of test samples (e.g., 10) can be taken for the above test, and the average value of each test sample is taken as the final test result. The test instrument can be ZEISS Sigma 300. It should be noted that when the particles to be measured are irregularly shaped, the distance between the two most distant points on the particles to be measured is taken as the particle size of the particles to be measured.

[0237] In some embodiments, the polymeric binder particles can include vinylidene fluoride-based polymer particles, such as polyvinylidene fluoride (PVDF) particles and / or copolymer particles of a vinylidene fluoride monomer and a comonomer.

[0238] The comonomer can include at least one of an olefin monomer, a fluorine-containing olefin monomer, a chlorine-containing olefin monomer, an acrylate monomer, an acrylic monomer, and a fluorine ether monomer.

[0239] Optionally, the comonomer can include at least one of trifluoroethylene, trifluorochloroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl) ether (e.g., perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether), perfluoro(1,3-dioxolane), and perfluoro(2,2-dimethyl-1,3-dioxolane).

[0240] In some embodiments, the thickness of the coating layer can be 0.5 μm-5 μm. The thickness of the coating layer refers to the thickness of the coating layer on one side of the porous base film. Optionally, the thickness of the coating layer 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, 0.8 μm-2 μm.

[0241] In some embodiments, the areal density of the coating layer can be 0.45 g / m 2 -5 g / m 2 .

[0242] In some embodiments, the porous base film can include a film or nonwoven web selected from any one or at least two of polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyether sulfone, polyphenylene ether, cyclic olefin copolymer, polyphenylene sulfide, and polyvinyl naphthalene.

[0243] The porous base film can be a single-layer film or a multi-layer composite film. When the porous base film is a multi-layer composite film, the materials of the layers can be the same or different.

[0244] In some embodiments, the thickness of the porous base film can be 4 μm-12 μm, optionally 4 μm-9 μm.

[0245] In some embodiments, the porosity of the porous base film can be 25%-60%, optionally 28%-50%.

[0246] 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 film can be greater than or equal to 1.2.

[0247] The volume distribution particle size Dv50 of the organic particles has the same unit as the average pore size of the porous base film, such as nm.

[0248] In this way, the problem of hole blocking can be reduced, and the air permeability and ion conductivity of the separation film can be improved.

[0249] In some embodiments, the average pore size of the porous base film can be 25 nm-82 nm.

[0250] The average pore size of the porous base film can be tested by using a capillary porosimetry tester (bubble point method). An exemplary testing method is as follows: a circular sample with a diameter of 25 mm is taken, 3-5 drops of wetting liquid are dropped on it, and after the sample is completely wetted, it is placed in a mold, and then an inert gas (such as nitrogen) is used to press the wetting liquid in the pore channels of the sample to be tested. The pressure and flow rate of the extrusion gas are inversely proportional to the pore size. By software sampling and pressure and pore size conversion analysis, the average pore size of the sample to be tested is obtained. The testing instrument can be a CFP 1500 pore size analyzer from PMI Company, and the testing pressure can be 100 psi to 350 psi.

[0251] In some embodiments, the thickness of the separation film can be 5 μm-14 μm, optionally 5 μm-12 μm, 6 μm-12 μm. In this way, the energy density of the secondary battery cell can be improved.

[0252] The glass transition temperature T g The test can be performed as follows: an appropriate amount of sample (such as 5 mg-15 mg) is placed in a differential scanning calorimeter (DSC) crucible, shaken to level, and covered with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60 mL / min, protective gas 20 mL / min; program settings: temperature increase from 25℃ to 200℃ at a rate of 10℃ / min, hold for 5 min to eliminate thermal history, temperature decrease from 200℃ to -40℃ at a rate of 10℃ / min, and temperature increase from -40℃ to 300℃ at a rate of 10℃ / min. The glass transition temperature T g of the organic particles is obtained from the DSC curve. g

[0253] The glass transition temperature T g is the transition temperature from the glass state to the high-elasticity state, which shows a step change on the DSC curve.

[0254] The organic particles have no glass transition temperature T g below 300℃, which means that the DSC curve of the organic particles does not show a step change below 300℃.

[0255] ​Dv50 represents the particle size corresponding to the cumulative volume distribution percentage of 50%, which can be tested by referring to GB / T 19077-2016 and using a laser particle size analyzer. During the test, a clean small beaker is taken, 1 g of the sample to be tested is added, 20 ml of deionized water is added, and ultrasonic treatment is performed at 53 KHz / 120 W for 5 min to ensure that the sample is completely dispersed. After the light path system is cleaned, the background is automatically tested. The solution to be tested after ultrasonic treatment is stirred to make it uniformly dispersed, and then placed in the sample cell as required to start measuring the particle size. The testing instrument can be a MasterSizer 3000 laser particle size analyzer.

[0256] It should be noted that the coating parameters of the above-mentioned separation membrane are the coating parameters of one side of the porous base film. When the coating is arranged on both sides of the porous base film, as long as the coating parameters of any one side meet the present disclosure, it is considered to fall within the protection scope of the present disclosure.

[0257] The separation membrane can be prepared according to methods known in the art.

[0258] In some embodiments, a slurry including organic particles and a binder can be coated on at least one side of the porous base film, and after drying, the separation membrane is obtained.

[0259] In some embodiments, the slurry can further include polymer binder particles, and after drying of the slurry, the polymer binder particles are embedded in the organic particles and form protrusions on the surface of the coating.

[0260] In some embodiments, the preparation method of the separation membrane can include the steps of: coating a heat-resistant layer slurry including organic particles and a binder on at least one side of the porous base film, and after drying, forming a heat-resistant layer; and coating an adhesive layer slurry including polymer binder particles and a binder on at least a part of the surface of the heat-resistant layer, and after drying, obtaining the separation membrane.

[0261] In some embodiments, the preparation method of the separation membrane can include the steps of: coating a heat-resistant slurry including organic particles and a binder on one side of the porous base film, and coating an adhesive layer slurry including polymer binder particles and a binder on at least a part of the surface of the other side of the porous base film, and after drying, obtaining the separation membrane.

[0262] In some embodiments, the solvent of the slurry can be water, for example, deionized water.

[0263] In some embodiments, the slurry can further include other components, for example, can further include dispersants and / or wetting agents, etc.

[0264] The present disclosure also provides a secondary battery cell. The secondary battery cell includes the separation membrane provided by the embodiments of the present disclosure.

[0265] The secondary battery cell further includes a positive electrode tab, a negative electrode tab, and an electrolyte. The positive electrode tab, the separator, and the negative electrode tab can form an electrode assembly through a rolling process and / or a stacking process.

[0266] The secondary battery cell provided by the present disclosure can include, but is not limited to, a lithium battery cell, a sodium battery cell, etc. The composition of the positive electrode tab, the negative electrode tab, and the electrolyte can vary depending on the type of the secondary battery cell.

[0267] [Positive electrode tab]

[0268] In some embodiments, the positive electrode tab can include a positive current collector and a positive film layer disposed on at least one surface of the positive current collector and including a positive active material. For example, the positive current collector has two surfaces opposite in the thickness direction of the positive current collector, and the positive film layer is disposed on either one or both of the two opposite surfaces of the positive current collector.

[0269] For example, in the case of a lithium battery cell, the positive active material can include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and modified compounds thereof. Examples of the lithium transition metal oxides can 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 modified compounds thereof. Examples of the lithium-containing phosphates can include, but are not limited to, one or more of lithium iron phosphate, a composite of lithium iron phosphate and carbon, lithium manganese phosphate, a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon, and modified compounds thereof. In some embodiments, in order to further improve the energy density of the secondary battery cell, the positive active material can include one or more of lithium transition metal oxides of the general formula Li a Ni b Co c M d O e A f 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes, but is not limited to, one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, and B, and A includes, but is not limited to, one or more of N, F, S, and Cl.

[0270] For example, the positive active material can include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5Co 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.

[0271] During the charging and discharging process, Li undergoes insertion / extraction and consumption in a single secondary battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to a secondary battery cell, the molar Li content changes after charge-discharge cycles. Similarly, in the examples of positive electrode active materials in this disclosure, the molar O content is only a theoretical value. Lattice oxygen release causes changes in the molar O content, and the actual molar O content will also fluctuate.

[0272] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-xIn 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.

[0273] 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.

[0274] 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.

[0275] 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.

[0276] 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.

[0277] 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.

[0278] [Negative electrode plate]

[0279] In some embodiments, the negative electrode tab can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector and including a negative electrode active material. For example, the negative electrode current collector has two surfaces opposite in the thickness direction of the negative electrode current collector, and the negative electrode film layer is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0280] The negative electrode active material can employ materials known in the art that are useful for secondary battery cells. As an example, the negative electrode active material can include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. The silicon-based materials can include, but are not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy materials. The tin-based materials can include, but are not limited to, one or more of elemental tin, tin oxide, and tin alloy materials.

[0281] In some embodiments, the negative electrode film layer can further include a negative electrode conductive agent. As an example, the negative electrode conductive agent can include, but is not limited to, one or more of super P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0282] In some embodiments, the negative electrode film layer can further include a negative electrode binder. As an example, the negative electrode binder can include, but is not limited to, one or more of styrene butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethylacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0283] In some embodiments, the negative electrode film layer can further include other auxiliary agents. As an example, the other auxiliary agents can include thickening agents, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, and the like.

[0284] In some embodiments, the negative electrode current collector can employ a metal foil or a composite current collector. As an example of the metal foil, a copper foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0285] The negative electrode film layer is usually formed by coating a negative electrode slurry on a negative electrode current collector, drying, and cold pressing. The negative electrode slurry is usually formed by dispersing a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and other optional additives in a solvent and stirring uniformly. The solvent can be N-methyl pyrrolidone (NMP) or deionized water, but is not limited thereto.

[0286] The negative electrode tab does not exclude other additional functional layers in addition to the negative electrode film layer. For example, in some embodiments, the negative electrode tab further includes a conductive primer layer (e.g., composed of a conductive agent and a binder) disposed on the surface of the negative electrode current collector and sandwiched between the negative electrode current collector and the negative electrode film layer.

[0287] In some embodiments, the negative electrode tab can adopt a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, etc. When the foamed metal is used as the negative electrode tab, the surface of the foamed metal can not be provided with a negative electrode active material, and of course can be provided with a negative electrode active material.

[0288] [Electrolyte]

[0289] The electrolyte plays a role in conducting ions between the positive electrode tab and the negative electrode tab.

[0290] In some embodiments, the electrolyte adopts an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0291] Taking a lithium battery cell as an example, the electrolyte salt can include but is not limited to one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0292] Taking a sodium battery cell as an example, the electrolyte salt can include but is not limited to one or more of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bisfluorosulfonylimide (NaFSI), sodium bis-trifluoromethanesulfonylimide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0293] In some embodiments, the organic solvent can include, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, crown ether.

[0294] In some embodiments, an additive can also be included in the electrolyte. For example, the additive can include a negative electrode film-forming additive, can also include a positive electrode film-forming additive, and can also include an additive capable of improving certain performance of the secondary battery cell, such as an additive capable of improving overcharge performance, an additive capable of improving high-temperature performance, an additive capable of improving low-temperature performance, and the like.

[0295] Optionally, the additive can include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propane sultone (PS), and vinyl sulfate (DTD).

[0296] Methods for preparing secondary battery cells are well known. In some embodiments, a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte can be assembled to form a secondary battery cell. As an example, a positive electrode sheet, a separator, and a negative electrode sheet can be formed into an electrode assembly through a winding process and / or a stacking process, the electrode assembly can be placed in an outer package, an electrolyte described above can be injected after drying, and the secondary battery cell can be obtained after processes such as vacuum packaging, standing, and formation.

[0297] Embodiments

[0298] The following examples more specifically describe the disclosure disclosed in the present disclosure, and these examples are merely illustrative, as various modifications and changes within the scope of the disclosure disclosed in the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on mass, and all reagents used in the examples are commercially available or synthesized according to conventional methods and used directly without further purification, and the instruments used in the examples are commercially available.

[0299] A commercially available phenol and formaldehyde-based resol resin material having a free phenol content of 4% and a free aldehyde content of 2% was placed in a curing oven, the atmosphere of which was set to an air atmosphere, and the temperature was set to 140°C, and the temperature was maintained for 3h. After the end of the curing, the temperature of the curing oven was increased to 275°C, and the temperature was maintained for 4h. After the end of the two curing processes, the cured phenol resin-based organic particles were removed, and after natural cooling in air, they were crushed, sand ground, sieved, and de-magnetized to obtain phenol resin-based organic particles 1-1#.

[0300] A commercially available phenol and formaldehyde-based resol resin material having a free phenol content of 4% and a free aldehyde content of 2% was placed in a curing oven, the atmosphere of which was set to an air atmosphere, and the temperature was set to 140°C, and the temperature was maintained for 3h. After the end of the curing, the temperature of the curing oven was increased to 290°C, and the temperature was maintained for 4h. After the end of the two curing processes, the cured phenol resin-based organic particles were removed, and after natural cooling in air, they were crushed, sand ground, sieved, and de-magnetized to obtain phenol resin-based organic particles 1-2#.

[0301] A commercially available phenol and formaldehyde-based resol resin material having a free phenol content of 4% and a free aldehyde content of 2% was placed in a curing oven, the atmosphere of which was set to an air atmosphere, and the temperature was set to 140°C, and the temperature was maintained for 3h. After the end of the curing, the temperature of the curing oven was increased to 260°C, and the temperature was maintained for 4h. After the end of the two curing processes, the cured phenol resin-based organic particles were removed, and after natural cooling in air, they were crushed, sand ground, sieved, and de-magnetized to obtain phenol resin-based organic particles 1-3#.

[0302] A commercially available phenol and formaldehyde-based resol resin material having a free phenol content of 10% and a free aldehyde content of 10% was placed in a curing oven, the atmosphere of which was set to an air atmosphere, and the temperature was set to 140°C, and the temperature was maintained for 3h. After the end of the curing, the cured phenol resin-based organic particles were removed, and after natural cooling in air, they were crushed, sand ground, sieved, and de-magnetized to obtain phenol resin-based organic particles D1-1#.

[0303] Organic particle performance test

[0304] (1) Glass transition temperature Tg of the organic particles g Test

[0305] Take an appropriate amount of sample (for example, 5 mg-15 mg) and place it in a differential scanning calorimeter (DSC) crucible, shake it flat, and cover it with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60 mL / min, protective gas 20 mL / min; program settings: temperature rise from 25℃ to 200℃ at a rate of 10℃ / min, hold for 5 min to eliminate thermal history, temperature drop from 200℃ to -40℃ at a rate of 10℃ / min, and temperature rise from -40℃ to 300℃ at a rate of 10℃ / min. The glass transition temperature Tg of the organic particles is obtained from the DSC curve. g or determine whether the organic particles have a glass transition temperature Tg g .

[0306] (2) Melting point test of organic particles

[0307] Take an appropriate amount of sample (for example, 5 mg-15 mg) and place it in a differential scanning calorimeter (DSC) crucible, shake it flat, and cover it with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60 mL / min, protective gas 20 mL / min; program settings: temperature rise from 25℃ to 200℃ at a rate of 10℃ / min, hold for 5 min to eliminate thermal history, temperature drop from 200℃ to -40℃ at a rate of 10℃ / min, and temperature rise from -40℃ to 300℃ at a rate of 10℃ / min. Determine whether the organic particles have a melting point from the DSC curve.

[0308] (3) Cyclic voltammetry test

[0309] Take the organic particles, the binder polyacrylate, and the conductive agent conductive carbon black, and dissolve them in water according to a solid content mass ratio of 64:7:29 to prepare a slurry. The slurry is coated on an aluminum foil as a positive electrode, and a lithium foil is used as a negative electrode to assemble a coin cell. The coin cell is subjected to a cyclic voltammetry (CV) test at a scan rate of 0.10 mV / s and a voltage range of 2.50 V-5.00 V, and the voltage corresponding to the peak point of the first cycle CV curve is taken as the oxidation peak potential. The electrolyte salt of the electrolyte used in the test is LiPF6, and the concentration is 1 mol / L. The solvent of the electrolyte is obtained by mixing ethylene carbonate (EC) and methyl ethyl carbonate (EMC) according to a volume ratio of 3:7.

[0310] The above-prepared organic particles 1-1# to 1-3# meet the following characteristics: the phenolic resin-based organic particles are thermosetting resol polymers, which have no melting point, and no glass transition temperature Tg below 300℃ g .

[0311] Next, the above-prepared organic particles are used in a separator film to verify their effect on the performance of the separator film and the secondary battery monomer.

[0312] The preparation process of the isolation film is as follows.

[0313] A commercially available polyethylene microporous film with a thickness of 7 μm was used as the porous base film. The organic particles, dispersant sodium carboxymethyl cellulose, and binder polyacrylate prepared above were mixed uniformly in deionized water at a solid mass ratio of 90:2:8 to obtain a coating slurry. The coating slurry was uniformly coated on both surfaces of the porous base film, and the solvent was removed by drying to obtain an isolation film. The coating thickness was 1.5 μm, and the thickness of the isolation film was 10 μm.

[0314] The preparation process of the secondary battery cell is as follows.

[0315] The positive electrode active material LiNi 0.6 Co 0.2 Mn 0.2 O2, the positive electrode binder polyvinylidene fluoride (PVDF), and the positive electrode conductive agent carbon black were added into N-methyl pyrrolidone (NMP) at a mass ratio of 97:2:1, and then fully stirred and mixed uniformly to prepare a positive electrode slurry. The positive electrode slurry was uniformly coated on the positive electrode current collector aluminum foil, and then subjected to drying, cold pressing, and slitting to obtain a positive electrode sheet.

[0316] The negative electrode active material artificial graphite, the negative electrode conductive agent acetylene black, the negative electrode binder styrene-butadiene rubber (SBR), and the thickening agent sodium carboxymethyl cellulose were added into deionized water at a mass ratio of 96.0:1.5:1.5:1, and then fully stirred and mixed uniformly to prepare a negative electrode slurry. The negative electrode slurry was uniformly coated on the negative electrode current collector copper foil, and then subjected to drying, cold pressing, and slitting to obtain a negative electrode sheet.

[0317] At 25°C, ethylene carbonate (EC) and methyl ethyl carbonate (EMC) were mixed at a volume ratio of 3:7 to obtain a mixed solvent, and then LiPF6 and fluoroethylene carbonate (FEC) were dissolved in the mixed solvent to obtain an electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of FEC was 3% based on the mass of the electrolyte.

[0318] The positive electrode sheet, the isolation film, and the negative electrode sheet were stacked and wound in sequence, and then hot-pressed to form an electrode assembly. The electrode assembly was then packaged in an aluminum-plastic film by top-side sealing, and then subjected to processes such as electrolyte injection, standing, formation, aging, degassing, and secondary sealing to obtain a soft-packaged secondary battery cell.

[0319] Performance test

[0320] (1) Test of the heat shrinkage rate of the isolation film

[0321] The test of the heat shrinkage rate of the isolation film can refer to GB / T 36363-2018.

[0322] The separator film was punched into a sample with a width of 50 mm and a length of 100 mm by a punch press, 5 parallel samples were placed on an A4 paper, and then the A4 paper with the samples was placed on the corrugated paper with a thickness of 1 mm to 5 mm.

[0323] The temperature of the air blast oven was set to 130℃, and after the temperature reached the set temperature and stabilized for 60 min, the A4 paper placed on the corrugated paper was placed in the air blast oven, and the timing started. After reaching the set time (1 h in this disclosure), the length and width of the separator film were measured, and the values were marked as a and b, respectively.

[0324] The heat shrinkage rate was calculated as follows: longitudinal (MD) heat shrinkage rate = [(100-a) / 100]x100%, transverse (TD) heat shrinkage rate = [(50-b) / 50]x100%, and the average value of 3 parallel samples was taken as the test result.

[0325] (2) Test of the first coulombic efficiency of the secondary battery cell

[0326] The secondary battery cell was charged at 1 / 3C constant current to 4.5V at 25℃, then charged at 4.5V constant voltage to a current of 0.05C, rested for 5 min, and then discharged at 1 / 3C constant current to 2.8V to obtain the initial charge capacity and the initial discharge capacity. The first coulombic efficiency of the secondary battery cell = initial discharge capacity / initial charge capacity x 100%.

[0327] Table 1

[0328] From the above test results, it can be seen that the phenolic resin-based organic particles prepared in the embodiments of the disclosure have high electrochemical stability, which can improve the heat resistance of the separator film and the first coulombic efficiency of the high-voltage secondary battery cell.

[0329] Next, the phenolic resin-based organic particles were replaced with polymer particles containing triazine ring structure units.

[0330] Commercially available melamine-formaldehyde resin particles were cured in an air atmosphere at 285℃ for 5h, and then crushed, sand ground, sieved, and demagnetized to obtain polymer particles 2-1# containing triazine ring structure units. The molar ratio of raw material formaldehyde to melamine in the melamine-formaldehyde resin was 2.8:1.

[0331] Commercially available melamine-formaldehyde resin particles were cured in an air atmosphere at 265℃ for 5h, and then crushed, sand ground, sieved, and demagnetized to obtain polymer particles 2-2# containing triazine ring structure units. The molar ratio of raw material formaldehyde to melamine in the melamine-formaldehyde resin was 2.8:1.

[0332] The commercially available melamine formaldehyde resin particles were cured at 245℃ for 6h in air atmosphere, followed by crushing, sanding, sieving, and demagnetization to obtain polymer particles 2-3# containing triazine ring structural units. The raw material formaldehyde to melamine molar ratio in the melamine formaldehyde resin was 2.8:1.

[0333] The commercially available melamine formaldehyde resin particles were cured at 285℃ for 5h in air atmosphere, followed by crushing, sanding, sieving, and demagnetization to obtain polymer particles 2-4# containing triazine ring structural units. The raw material formaldehyde to melamine molar ratio in the melamine formaldehyde resin was 3.0:1.

[0334] The commercially available melamine formaldehyde resin particles were cured at 150℃ for 5h in air atmosphere, followed by crushing, sanding, sieving, and demagnetization to obtain polymer particles D2-1# containing triazine ring structural units. The raw material formaldehyde to melamine molar ratio in the melamine formaldehyde resin was 2.8:1.

[0335] The above prepared organic particles 2-1# to 2-4# satisfy the following characteristics: they have no melting point, and no glass transition temperature T g .

[0336] Table 2

[0337] From the above test results, it can be seen that the polymer particles containing triazine ring structural units prepared in the embodiments of the present disclosure have high electrochemical stability, which can improve the heat resistance of the separator and the first coulomb efficiency of the high-voltage secondary battery cell.

[0338] Next, the phenolic resin organic particles are replaced with cross-linked styrene organic particles.

[0339] A pre-emulsion was prepared by emulsifying 0.8g of sodium dodecyl sulfate, 64mg of sodium persulfate, 20ml of deionized water, 35g of styrene, and 5g of divinylbenzene. 140g of deionized water was added to the reactor, heated to 68℃, and the above prepared pre-emulsion was added dropwise under nitrogen protection and stirring conditions. After 6h of reaction, the temperature was raised to 86℃ for 2h of curing reaction to obtain cross-linked styrene organic particle 3-1# emulsion. The solid content of the reaction system was 20%.

[0340] A pre-emulsion was prepared by emulsifying 0.8g of sodium dodecyl sulfate, 64mg of sodium persulfate, 20ml of deionized water, 35g of styrene, and 5g of divinylbenzene. 140g of deionized water was added to the reactor, heated to 68℃, and the above prepared pre-emulsion was added dropwise under nitrogen protection and stirring conditions. After 6h of reaction, the temperature was raised to 86℃ for 2h of curing reaction to obtain cross-linked styrene organic particle 3-1# emulsion. The solid content of the reaction system was 20%.

[0341] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 100 mg of sodium persulfate, 20 ml of deionized water, 35 g of styrene, and 5 g of divinylbenzene. 100 g of deionized water was added to the reactor, heated to 68°C, and the above-mentioned pre-emulsion was added dropwise under the condition of nitrogen protection and stirring. After 6 h of reaction, the temperature was increased to 86°C for 2 h of curing reaction to obtain a cross-linked styrene-based organic particle 3-4# emulsion. The solid content of the reaction system was 25%.

[0342] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 100 mg of sodium persulfate, 20 ml of deionized water, 35 g of styrene, and 5 g of divinylbenzene. 100 g of deionized water was added to the reactor, heated to 68°C, and the above-mentioned pre-emulsion was added dropwise under the condition of nitrogen protection and stirring. After 6 h of reaction, the temperature was increased to 86°C for 2 h of curing reaction to obtain a cross-linked styrene-based organic particle 3-4# emulsion. The solid content of the reaction system was 25%.

[0343] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 100 mg of sodium persulfate, 20 ml of deionized water, 30 g of styrene, and 10 g of divinylbenzene. 140 g of deionized water was added to the reactor, heated to 68°C, and the above-mentioned pre-emulsion was added dropwise under the condition of nitrogen protection and stirring. After 6 h of reaction, the temperature was increased to 86°C for 2 h of curing reaction to obtain a cross-linked styrene-based organic particle 3-5# emulsion. The solid content of the reaction system was 20%.

[0344] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 100 mg of sodium persulfate, 20 ml of deionized water, 39.5 g of styrene, and 0.5 g of divinylbenzene. 440 g of deionized water was added to the reactor, heated to 68°C, and the above-mentioned pre-emulsion was added dropwise under the condition of nitrogen protection and stirring. After 6 h of reaction, the temperature was increased to 86°C for 2 h of curing reaction to obtain a cross-linked styrene-based organic particle D3-1# emulsion. The solid content of the reaction system was 8%.

[0345] The above-prepared organic particles 3-1# to 3-5# satisfy the following characteristics: no melting point, glass transition temperature T g between 110°C and 154°C.

[0346] Table 3

[0347] From the above test results, it can be seen that the cross-linked styrene-based organic particles prepared by the embodiments of the present disclosure have high electrochemical stability, which can improve the heat resistance of the isolation film and the first coulomb efficiency of the high-voltage secondary battery cell.

[0348] Next, the phenolic resin-based organic particles were replaced with silicon-containing organic resin particles.

[0349] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 49.8 g of γ-methacryloxypropyl triisopropoxy silane, 3 g of 3-methacryloxypropyl triethoxy silane and 7.2 g of divinyl benzene. A reactor was taken, 210 g of deionized water was added, and the temperature was raised to 70°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 80°C for 1 h of curing reaction, and a silicon-containing organic resin particle 4-2# emulsion was obtained.

[0350] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 49.8 g of γ-methacryloxypropyl triisopropoxy silane, 3 g of 3-methacryloxypropyl triethoxy silane and 7.2 g of divinyl benzene. A reactor was taken, 210 g of deionized water was added, and the temperature was raised to 70°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 80°C for 1 h of curing reaction, and a silicon-containing organic resin particle 4-2# emulsion was obtained.

[0351] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 49.8 g of γ-methacryloxypropyl triisopropoxy silane, 3 g of 3-methacryloxypropyl triethoxy silane and 7.2 g of divinyl benzene. A reactor was taken, 210 g of deionized water was added, and the temperature was raised to 70°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 80°C for 1 h of curing reaction, and a silicon-containing organic resin particle 4-2# emulsion was obtained.

[0352] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 49.8 g of γ-methacryloxypropyl triisopropoxy silane, 3 g of 3-methacryloxypropyl triethoxy silane and 7.2 g of divinyl benzene. A reactor was taken, 210 g of deionized water was added, and the temperature was raised to 70°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 80°C for 1 h of curing reaction, and a silicon-containing organic resin particle 4-2# emulsion was obtained.

[0353] The above-prepared organic particles 4-1# to 4-3# meet the following characteristics: the silicon-containing organic resin particles are network structures formed with carbon-carbon bonds as the main chain, and the side chains contain siloxane structures, which have no melting point and no glass transition temperature T g .

[0354] Table 4

[0355] From the test results, it can be seen that the silicon-containing organic resin particles prepared by the embodiments of the present disclosure have high electrochemical stability, and can improve the heat resistance of the isolation film and the initial coulomb efficiency of the high-voltage secondary battery cell.

[0356] It should be noted that the present disclosure is not limited to the above embodiments. The above embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect within the scope of the technical solutions of the present disclosure are all included in the technical scope of the present disclosure. In addition, within the scope of the main idea of the present disclosure, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present disclosure.

Claims

1. 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 includes organic particles, and a cyclic voltammogram of the organic particles in a first cycle has no oxidation peak in a voltage range of 2.50V to 4.40V.

2. The secondary battery cell according to claim 1, wherein The cyclic voltammogram of the organic particles in a first cycle has no oxidation peak in a voltage range of 2.50V to 4.50V. 3.The secondary battery cell of any one of claims 1-2, wherein, The organic particles are at least one of thermosetting resin polymers or crosslinked polymers; and / or, The organic particles are amorphous polymers. 4.The secondary battery cell of any one of claims 1-3, 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 1μm, and is optionally 50nm-840nm.

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

6. The secondary battery cell according to any one of claims 1 to 5, wherein The organic particles 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. 7.The secondary battery cell of claim 6, wherein, The phenolic resin-based organic particles are thermosetting resol polymers; and / or, The phenolic resin-based organic particles have no glass transition temperature below 300℃; and / or, The volume distribution particle size Dv50 of the phenolic resin-based organic particles is 200nm-840nm. 8.The secondary battery cell of any one of claims 6-7, 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℃; and / or, The volume distribution particle size Dv50 of the polymer particles containing triazine ring structure units is 200nm-840nm.

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

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

11. The secondary battery cell according to any one of claims 6-10, wherein, The polymer particles containing triazine ring structure units include melamine-aldehyde-based polymers and derivatives thereof.

12. The secondary battery cell of claim 11, wherein, The melamine-aldehyde-based polymers and derivatives thereof include one or more of melamine formaldehyde, benzotriazine formaldehyde, melamine-benzotriazine formaldehyde, melamine-(2,4-diamino-1,3,5-triazine) formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine) formaldehyde, trihydrazinotriazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde. 13.The secondary battery cell of any one of claims 6-12, wherein, The crosslinked styrene-based organic particles include styrene or styrene derivative structure units and crosslinking structure units; and / or, The crosslinked styrenic organic particles have a glass transition temperature Tg g of 110 °C to 154 °C; and / or, The crosslinked styrene-based organic particles have a volume distribution particle size Dv50 of 88 nm to 295 nm.

14. The secondary battery cell according to claim 13, wherein, The styrene or styrene derivative structural unit includes one or more of a styrene structural unit, a 1-methyl-1-styrene structural unit, a 4-methylstyrene structural unit, a 2-methylstyrene structural unit, a 2,4-dimethylstyrene structural unit, and a 2,5-dimethylstyrene structural unit; and / or, 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 tripropyleneglycol diacrylate structural unit, a 2,2,4-trimethylhexanedioic acid bis[2-ethylaziridine] structural unit, a 1,1-nonanedioic acid bis[2-methylaziridine] structural unit, a 1,1-(1,3-phenylenedicarbonyl)bis[2-methylaziridine] structural unit, a trimethylolpropane tris(2-methyl-1-aziridinylpropionate) structural unit, a trimethylolpropane-tris[3-(2-methylaziridinyl)propionate] structural unit, and a pentaerythritol tris(3-aziridinyl)propionate structural unit.

15. The secondary battery cell according to any one of claims 6 to 14, wherein, The silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles have 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 silicon-containing organic resin particles have a volume distribution particle size Dv50 of 88 nm to 295 nm.

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

17. The secondary battery cell of any one of claims 15-16, wherein, The silicon-containing organic crosslinked 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 tripropyleneglycol diacrylate structural unit, a 2,2,4-trimethylhexanedioic acid bis[2-ethylaziridine] structural unit, a 1,1-nonanedioic acid bis[2-methylaziridine] structural unit, a 1,1-(1,3-phenylenedicarbonyl)bis[2-methylaziridine] structural unit, a trimethylolpropane tris(2-methyl-1-aziridinylpropionate) structural unit, a trimethylolpropane-tris[3-(2-methylaziridinyl)propionate] structural unit, and a pentaerythritol tris(3-aziridinyl)propionate structural unit.

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

2.

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

20. A battery device comprising a plurality of secondary battery cells according to any one of claims 1 to 19.

21. An electric device comprising the secondary battery cell according to any one of claims 1 to 19 or the battery device according to claim 20.

22. 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 a cyclic voltammogram of the organic particles in a first cycle has no oxidation peak in a voltage range of 2.50 V to 4.40 V.

23. The separator film according to claim 22, wherein, The organic particles are at least one of a thermosetting resin polymer or a crosslinked polymer; and / or, The organic particles are an amorphous polymer.

24. The separator film according to any one of claims 22 to 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 to 840 nm.

25. The separator membrane according to any one of claims 22-24, wherein, The organic particles have no melting point.

26. The separator membrane according to any one of claims 22-25, wherein, The organic particles comprise one or more of a phenol-aldehyde resin-based organic particle, a polymer particle containing a triazine ring structure unit, a crosslinked styrene-based organic particle, and a silicon-containing organic resin particle.

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