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

Abstract

A separator, a secondary battery cell, a battery device, and an electrical device. The secondary battery cell comprises a positive electrode plate, a negative electrode plate, and a separator. The separator is arranged between the positive electrode plate and the negative electrode plate. The separator comprises a porous base film and a coating located on at least one side of the porous base film. The coating comprises organic particles, and the organic particles satisfy the following condition: per 1 kg of organic particles, the number of magnetic foreign-matter particles having a size of 25-200 μm ranges from 0 to 30. The secondary battery cell has high gravimetric energy density, high reliability, and good long-term cycling stability.

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. 202410947810.1, filed on July 15, 2024, entitled “Separator, Battery Cell and Power Consuming Device” and Chinese Patent Application No. 202411382563.1, 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 higher and higher requirements for their energy density, service life, and reliability. Therefore, how to make the secondary battery cell have higher energy density and good cycle stability 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 have high mass energy density, high reliability, and good long-term cycle stability.

[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, the number of magnetic foreign particles with a size of 25 μm to 200 μm in 1 Kg of the organic particles being 0-30.

[0007] The secondary battery cell using the organic particles with small density can have higher mass energy density. The number of magnetic foreign particles with larger size in the organic particles of the present disclosure is small, which can reduce the risk of short circuit in the secondary battery cell caused by the magnetic foreign particles with larger size piercing the separator, and also can reduce the self-discharge degree of the secondary battery cell, thereby making the secondary battery cell have high reliability and good long-term cycle stability. Therefore, the secondary battery cell using the separator provided by the embodiments of the present disclosure can have high mass energy density, high reliability, and good long-term cycle stability.

[0008] In some embodiments, the organic particles satisfy: the number of magnetic foreign particle with size of 25-200 μm is 0-21 per 1 Kg of the organic particles. Thereby, the secondary battery cell can have better long-term cycle stability.

[0009] In some embodiments, the organic particles satisfy: the number of magnetic foreign particle with size greater than 200 μm is 0 per 1 Kg of the organic particles. Thereby, the secondary battery cell can have better long-term cycle stability.

[0010] In some embodiments, the magnetic foreign particles include one or more of elemental copper, elemental iron, elemental manganese, elemental nickel, elemental cobalt, alloys thereof, or oxides thereof.

[0011] In some embodiments, the content of Cu element in the organic particles is 0-10 ppm.

[0012] In some embodiments, the content of Fe element in the organic particles is 0-50 ppm.

[0013] In some embodiments, the content of Mn element in the organic particles is 0-5 ppm.

[0014] In some embodiments, the content of Ni element in the organic particles is 0-5 ppm.

[0015] In some embodiments, the content of Co element in the organic particles is 0-5 ppm.

[0016] In some embodiments, the true density of the organic particles is 1.0 g / cm 3 -2.0 g / cm 3 ; optionally 1.0 g / cm 3 -1.8 g / cm 3 .

[0017] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, optionally 50 nm-820 nm.

[0018] In some embodiments, the organic particles are at least one of thermosetting resin polymer or cross-linked polymer.

[0019] In some embodiments, the organic particles are amorphous polymer.

[0020] In some embodiments, the organic particles have no melting point.

[0021] The organic particles of the present disclosure have no melting point, indicating that the organic particles have good heat resistance and thermal stability, thereby better resisting thermal shrinkage of the porous base film, improving the heat resistance of the isolation film, and improving the reliability of the secondary battery cell.

[0022] In some embodiments, the organic particles include one or more of phenolic resin-based organic particles, polymer particles containing triazine ring structural units, crosslinked styrene-based organic particles, and silicon-containing organic resin particles.

[0023] In some embodiments, the phenolic resin-based organic particles are thermosetting resol polymers.

[0024] In some embodiments, the phenolic resin-based organic particles have no glass transition temperature below 300°C.

[0025] In some embodiments, the phenolic resin-based organic particles have a volume distribution particle size Dv50 of 200 nm to 820 nm.

[0026] The volume distribution particle size Dv50 of the polymer particles of the phenolic resin-based organic particles within the above range is advantageous for the isolation film to have good heat resistance and air permeability.

[0027] In some embodiments, the polymer particles containing triazine ring structural units include a bridging structure connecting the triazine ring structural units. Optionally, the bridging structure includes one or a combination of two or more of alkylene, alkylene ether, alkylene amine, ester group, and amide group.

[0028] In some embodiments, the polymer particles containing triazine ring structural units further have a substituent on the triazine ring structural units, the substituent including one or a combination of two or more of alkyl, alkenyl, phenyl, cycloalkyl, amine group, hydroxyl, and halogen.

[0029] In some embodiments, the polymer particles containing triazine ring structural units include at least one of melamine formaldehyde-based polymers and derivatives thereof, etherified melamine formaldehyde-based polymers and derivatives thereof, etherified melamine formaldehyde-polyol polymers and derivatives thereof, etherified melamine formaldehyde-polycarboxylic acid polymers and derivatives thereof, and etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof.

[0030] In some embodiments, the melamine formaldehyde-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, trihydrazinyl-s-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde.

[0031] In some embodiments, the etherified melamine formaldehyde polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzoguanamine formaldehyde, butyl etherified benzoguanamine formaldehyde.

[0032] In some embodiments, the etherified melamine formaldehyde-polyol polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde-ethylene glycol polymer, methyl etherified melamine formaldehyde-1,2-propanediol polymer, methyl etherified melamine formaldehyde-1,4-butanediol polymer, methyl etherified melamine formaldehyde-polyester polyol polymer, methyl etherified melamine formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine formaldehyde-ethylene glycol polymer, butyl etherified melamine formaldehyde-1,2-propanediol polymer, butyl etherified melamine formaldehyde-1,4-butanediol polymer, butyl etherified melamine formaldehyde-polyester polyol polymer.

[0033] In some embodiments, the etherified melamine formaldehyde-polycarboxylic acid polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde-oxalic acid polymer, methyl etherified melamine formaldehyde-malic acid polymer, methyl etherified melamine formaldehyde-succinic acid polymer, methyl etherified melamine formaldehyde-citric acid polymer, methyl etherified melamine formaldehyde-terephthalic acid polymer, methyl etherified melamine formaldehyde-phthalic acid polymer, butyl etherified melamine formaldehyde-oxalic acid polymer, butyl etherified melamine formaldehyde-malic acid polymer, butyl etherified melamine formaldehyde-citric acid polymer, butyl etherified melamine formaldehyde-terephthalic acid polymer, butyl etherified melamine formaldehyde-phthalic acid polymer.

[0034] In some embodiments, the etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde-oxamide polymer, methyl etherified melamine formaldehyde-malonamide polymer, methyl etherified melamine formaldehyde-isophthalimide polymer, butyl etherified melamine formaldehyde-oxamide polymer.

[0035] In some embodiments, the polymer particles containing triazine ring structural units have no glass transition temperature below 300°C.

[0036] In some embodiments, the polymer particles containing triazine ring structural units have a volume distribution particle size Dv50 of 200-820 nm.

[0037] The volume distribution particle size Dv50 of the polymer particles containing triazine ring structural units within the above range is conducive to the isolation film having good heat resistance and air permeability.

[0038] In some embodiments, the crosslinked styrene-based organic particles comprise styrene or styrene derivative structural units and crosslinking structural units.

[0039] 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.

[0040] In some embodiments, the crosslinking structural units comprise one or more of divinylbenzene structural units, ethylene glycol dimethacrylate structural units, pentaerythritol tetraacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, tripropylene glycol diacrylate structural units, N,N-methylenebisacrylamide structural units, N,N'-vinylbisacrylamide structural units, 1,3,5-triacryloylhexahydro-1,3,5-triazine structural units, trisallyl isocyanurate structural units.

[0041] In some embodiments, the crosslinked styrene-based organic particles have a glass transition temperature T g of 106°C to 160°C.

[0042] The crosslinked styrene-based organic particles have a glass transition temperature T g that is high, and 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.

[0043] In some embodiments, the crosslinked styrene-based organic particles have a volume distribution particle size Dv50 of 85 nm to 320 nm.

[0044] The crosslinked styrene-based organic particles have a volume distribution particle size Dv50 within the above range, which is advantageous for the separator film to have good heat resistance and air permeability.

[0045] 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.

[0046] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles are network structures formed with carbon-carbon bonds as the main chain, and the side chains contain siloxane structures.

[0047] In some embodiments, the silicon-containing organic crosslinked resin particles comprise a crosslinking structural unit.

[0048] 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.

[0049] In some embodiments, the silicon-containing organic resin particles have no glass transition temperature below 300°C.

[0050] In some embodiments, the silicon-containing organic resin particles have a volume distribution particle size Dv50 of 85 nm-320 nm.

[0051] The volume distribution particle size Dv50 of the silicon-containing organic resin particles within the above range is advantageous for the isolation membrane to have good heat resistance and air permeability.

[0052] In some embodiments, the coating further comprises a binder.

[0053] In some embodiments, the mass content of the organic particles in the coating is 50%-99% based on the total mass of the coating.

[0054] In some embodiments, the thickness of the coating is 0.5 μm-5 μm.

[0055] In some embodiments, the areal density of the coating is 0.45 g / m 2 -5 g / m 2 .

[0056] 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 1.1.

[0057] In a second aspect, the present disclosure provides a battery device comprising a plurality of secondary battery cells of the first aspect of the present disclosure.

[0058] 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.

[0059] In a fourth aspect, the present disclosure provides an isolation film comprising a porous base film and a coating layer on at least one side of the porous base film, the coating layer comprising organic particles, the organic particles satisfying: the number of magnetic foreign particle having a size of 25 μm to 200 μm is 0-30 per 1 Kg of the organic particles.

[0060] In some embodiments, the organic particles have a true density of 1.0 g / cm 3 -2.0 g / cm 3 ; and optionally 1.0 g / cm 3 -1.8 g / cm 3 .

[0061] In some embodiments, the organic particles have a volume distribution particle size Dv50 of less than 1 μm, and optionally 50 nm-820 nm.

[0062] In some embodiments, the organic particles are at least one of thermosetting resin polymers or cross-linked polymers.

[0063] In some embodiments, the organic particles are amorphous polymers.

[0064] In some embodiments, the organic particles have no melting point.

[0065] 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

[0066] 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 as follows. Obviously, the drawings described below are only some of the embodiments of the present disclosure, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of the drawings.

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

[0068] FIG. 2 shows a schematic diagram of a power consuming device according to some embodiments of the present disclosure.

[0069] In the drawings, the drawings are not necessarily drawn according to the actual scale. DETAILED DESCRIPTION

[0070] 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.

[0071] 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.

[0072] Unless otherwise specified, all embodiments and optional embodiments of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0073] Unless otherwise specified, all technical features and optional technical features of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0074] If there is no special description, 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), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0075] If there is no special description, in the present disclosure, the terms "first", "second", etc. are used to distinguish different objects, not to describe a specific order or primary and secondary relationship.

[0076] In the present disclosure, the terms "a plurality of" and "a plurality of" refer to two or more.

[0077] In the description of the embodiments of the present disclosure, if there is no special description, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0078] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25℃.

[0079] 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.

[0080] 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.

[0081] 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 encapsulate 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-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0082] 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 component.

[0083] In some embodiments, the battery cell assembly is generally formed by arranging a plurality of secondary battery cells.

[0084] As an example, the battery cell assembly can be a battery module formed by arranging and fixing a plurality of secondary battery cells into one independent module. As an example, the battery module can be formed by bundling a plurality of secondary battery cells with a cable tie.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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. Here, the enclosed space means covered or closed, and can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] In the context of the present disclosure, the organic particles mainly play a role in improving the heat resistance in the coating of the separator film, and almost have no adhesion.

[0094] The separator film is an important component for supporting the secondary battery cell to complete the electrochemical process of charging and discharging. Commonly used separator films 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 film, boehmite or alumina is currently 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.

[0095] The use of organic particles with a smaller density to replace boehmite and alumina can improve the energy density of the secondary battery cell. However, the containers and devices used in the current industrial-grade organic particle preparation process are mostly made of metal, and in addition, when the size of the prepared organic particles is large, it needs to be crushed to the nanoscale for better application in the separator film, and the crushing device is also mostly made of metal. Therefore, during the entire preparation process of the nanoscale organic particles, magnetic foreign particles are inevitably introduced. The magnetic foreign particles can have a negative impact on the performance of the secondary battery cell, such as increasing the self-discharge degree of the secondary battery cell, increasing the internal resistance of the secondary battery cell, reducing the cycle stability of the secondary battery cell, and possibly puncturing the separator film to cause internal short circuit of the secondary battery cell.

[0096] Based on this, the embodiments of the present disclosure provide a separator film, which can enable the secondary battery cell using the same to have high-quality energy density, high reliability, and good long-term cycle stability.

[0097] The isolation film provided by the embodiments of the present disclosure includes a porous base film and a coating layer located on at least one side of the porous base film, and the coating layer includes organic particles and a binder. The organic particles satisfy that the number of magnetic foreign particle with a size of 25-200 mu m is 0-30 per 1 Kg of the organic particles. 0 means that the organic particles do not contain magnetic foreign particles with a size of 25-200 mu m.

[0098] Both the porous base film and the coating layer have a pore structure, so that the isolation film has good air permeability and facilitates the passage of ions. The organic particles in the coating layer are connected to each other and fixed by the binder, and the gap between the organic particles can form a pore structure.

[0099] The organic particles have a small density, and the secondary battery cell using the same can have a higher mass energy density.

[0100] The number of magnetic foreign particles with a larger size in the organic particles of the present disclosure is small, which can reduce the risk of the larger size magnetic foreign particles piercing the isolation film to cause a short circuit in the secondary battery cell, and also reduce the self-discharge degree of the secondary battery cell, so that the secondary battery cell has high reliability and good long-term cycle stability.

[0101] Therefore, the secondary battery cell using the isolation film provided by the embodiments of the present disclosure can have high mass energy density, high reliability and good long-term cycle stability.

[0102] In some embodiments, the organic particles further satisfy that the number of magnetic foreign particles with a size of 25-200 mu m is 0-21 per 1 Kg of the organic particles.

[0103] Thus, the secondary battery cell can have better long-term cycle stability.

[0104] In some embodiments, the organic particles further satisfy that the number of magnetic foreign particles with a size greater than 200 mu m is 0 per 1 Kg of the organic particles.

[0105] Thus, the secondary battery cell can have better long-term cycle stability.

[0106] In some embodiments, the magnetic foreign particles can include one or more of the elemental substance, alloy or oxide of copper, iron, manganese, nickel, and cobalt.

[0107] In some embodiments, the content of Cu element in the organic particles can be 0-10 ppm.

[0108] In some embodiments, the content of Fe element in the organic particles can be 0-50 ppm.

[0109] In some embodiments, the content of Mn element in the organic particles can be 0-5 ppm.

[0110] In some embodiments, the content of Ni element in the organic particles can be 0-5 ppm.

[0111] In some embodiments, the content of Co element in the organic particles can be 0-5 ppm.

[0112] 0 indicates that the organic particles do not contain the corresponding metal element.

[0113] The morphology and quantity of the magnetic foreign particle in the organic particles can be determined by a scanning electron microscope (SEM). When testing, the magnetic foreign particles in the organic particles can be extracted using a high-strength magnetic bar, and then adhered to a conductive tape, and the morphology is observed by a scanning electron microscope (SEM) and counted to calculate the quantity per unit mass, i.e., the quantity of the magnetic foreign particles in 1 Kg of the organic particles.

[0114] The content of the foreign metal element in the organic particles can be determined by inductively coupled plasma optical emission spectrometry (ICP-OES). When testing, the magnetic foreign particles in the organic particles can be extracted using a high-strength magnetic bar, and then the magnetic foreign particles are separated from the magnetic bar, and then strong acid is added to dissolve the magnetic foreign particles, and the mass content of the foreign metal elements, such as Cu, Fe, Mn, Ni, Co, and the like, is detected by inductively coupled plasma optical emission spectrometry (ICP-OES).

[0115] In some embodiments, the true density of the organic particles can be 1.0 g / cm 3 -2.0 g / cm 3 . Alternatively, the true density of the organic particles can be 1.0 g / cm 3 -1.8 g / cm 3 .

[0116] At present, the true density of inorganic particles such as boehmite and alumina is usually 2.5 g / cm 3 -3.5 g / cm 3 . The true density of the organic particles of the present disclosure is small, so that the secondary battery cell using the isolation film of the present disclosure has a higher mass energy density.

[0117] In some embodiments, the volume distribution particle size Dv50 of the organic particles is less than 1 μm, and can be 50 nm-820 nm, 85 nm-820 nm.

[0118] 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.

[0119] The organic particles of the present disclosure are at least one of a thermosetting resin polymer or a crosslinked polymer.

[0120] A thermosetting resin polymer refers to a polymer product that hardens irreversibly upon curing and does not soften or melt upon heating once cured.

[0121] A crosslinked polymer refers to a polymer product obtained when crosslinking bonds are formed between monomer units.

[0122] The organic particles of the present disclosure are amorphous polymers.

[0123] In some embodiments, the organic particles have no melting point.

[0124] The organic particles of the present disclosure have no melting point, indicating that the organic particles have 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.

[0125] The melting point can be tested according to the following method: take an appropriate amount of sample (e.g. 5-15 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. Determine whether the organic particles have a melting point below 300°C by the DSC curve. The organic particles have no melting point, meaning that the DSC curve of the organic particles has no melting peak.

[0126] In some embodiments, the organic particles can include one or more of a phenol formaldehyde 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.

[0127] In some embodiments, the phenol formaldehyde resin-based organic particle is a thermosetting resin polymer.

[0128] In some embodiments, the phenol formaldehyde resin-based organic particle is a thermosetting resol polymer.

[0129] The raw material of the phenolic resin-based organic particle can include a phenolic compound and an aldehyde compound. In some embodiments, the phenolic compound can include one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cardanol. In some embodiments, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0130] In some embodiments, the phenolic resin-based organic particle has no glass transition temperature below 300°C.

[0131] The phenolic resin-based organic particle has no glass transition temperature below 300°C, which indicates that the organic particle has good heat resistance and thermal stability, and thus can better resist thermal shrinkage of the porous base film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0132] In some embodiments, the volume distribution particle size Dv50 of the phenolic resin-based organic particle can be 200 nm-820 nm.

[0133] The volume distribution particle size Dv50 of the polymer particle of the phenolic resin-based organic particle is within the above range, which is conducive to the separator film having good heat resistance and air permeability.

[0134] The polymer particle containing a triazine ring structure unit of the present disclosure further includes a bridging structure connecting the triazine ring structure unit.

[0135] The polymer particle containing a triazine ring structure unit has a plurality of triazine ring structure units in the molecular structure, and the bridging structure refers to a group connecting the triazine ring structure unit, and each bridging structure is the same or different.

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

[0137] More optionally, the bridging structure can include one or a combination of two or more of a methylene group, a methylene ether group, and a methylene amine group.

[0138] In some embodiments, the triazine ring structure unit of the polymer particle containing a triazine ring structure unit can further have a substituent group, and the substituent group can include a combination of one or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, a hydroxyl group, and a halogen.

[0139] In some embodiments, the polymer particle containing a triazine ring structure unit can include at least one of a melamine aldehyde-based polymer and a derivative thereof, an etherified melamine aldehyde-based polymer and a derivative thereof, an etherified melamine aldehyde-polyol polymer and a derivative thereof, an etherified melamine aldehyde-polybasic acid polymer and a derivative thereof, and an etherified melamine aldehyde-polyamine amide polymer and a derivative thereof.

[0140] In some embodiments, the melamine aldehyde polymer and derivatives thereof can include melamine formaldehyde polymer and derivatives thereof.

[0141] Optionally, the melamine aldehyde polymer and derivatives thereof can include one or more of melamine formaldehyde, benzoguanamine formaldehyde, melamine-benzoguanamine formaldehyde, melamine-(2,4-diamino-l,3,5-triazine) formaldehyde, melamine-(6-methyl-l,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-l,3,5-triazine) formaldehyde, trihydrazinotriazine formaldehyde, melamine-(2-amino-4-methylamino-l,3,5-triazine) formaldehyde, melamine-(2,4-diamino-6-dimethylamino-l,3,5-triazine) formaldehyde.

[0142] In some embodiments, the etherified melamine aldehyde polymer and derivatives thereof can include etherified melamine formaldehyde polymer and derivatives thereof.

[0143] In some embodiments, the etherified melamine aldehyde polymer and derivatives thereof can include methyl etherified melamine aldehyde polymer and derivatives thereof, ethyl etherified melamine aldehyde polymer and derivatives thereof, butyl etherified melamine aldehyde polymer and derivatives thereof, methyl-butyl mixed etherified melamine aldehyde polymer and derivatives thereof.

[0144] Optionally, the etherified melamine aldehyde polymer and derivatives thereof can include methyl etherified melamine formaldehyde polymer and derivatives thereof, ethyl etherified melamine formaldehyde polymer and derivatives thereof, butyl etherified melamine formaldehyde polymer and derivatives thereof, methyl-butyl mixed etherified melamine formaldehyde polymer and derivatives thereof.

[0145] The etherified melamine aldehyde polymer and derivatives thereof can include one or more of partially etherified melamine aldehyde polymer and derivatives thereof, fully etherified melamine aldehyde polymer and derivatives thereof. Optionally, the etherified melamine aldehyde polymer and derivatives thereof can include fully etherified melamine aldehyde polymer and derivatives thereof.

[0146] In some embodiments, the etherified melamine aldehyde polymer and derivatives thereof can include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzoguanamine formaldehyde, butyl etherified benzoguanamine formaldehyde.

[0147] The etherified melamine aldehyde-polyol polymer and derivatives thereof refer to the etherified melamine aldehyde resin and polyol high temperature cross-linking curing reaction product. Optionally, the molar ratio of the etherified melamine aldehyde resin and polyol can be 1:2-1:6.

[0148] In some embodiments, the polyol can include one or more of dihydric alcohol, trihydric alcohol, tetrahydric alcohol. Optionally, the polyol can include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethyl butyl propylene glycol, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyol, polyester polyol. More optionally, the polyol can include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, polyvinyl alcohol, polyester polyol.

[0149] Optionally, the polyester polyol can include one or more of polyethylene adipate glycol, poly-1,4-butanediol adipate glycol, polypropylene adipate glycol, polyneopentyl glycol adipate glycol, polyneopentyl glycol-1,6-hexanediol adipate glycol, polyhexanediol adipate glycol, polycarbonate glycol, polycaprolactone glycol.

[0150] Optionally, the polyether polyol can include one or more of polypropylene oxide diol, polypropylene oxide triol, polytetrahydrofuran diol.

[0151] Optionally, the molecular weight of the polyester polyol can be below 5000, optionally below 2000.

[0152] Optionally, the molecular weight of the polyether polyol can be below 5000, optionally below 2000.

[0153] Optionally, the molecular weight of the polyvinyl alcohol can be below 5000, optionally below 2000.

[0154] In some embodiments, the etherified melamine aldehyde-polyol polymer and its derivatives can include one or more of methyl etherified melamine formaldehyde-ethylene glycol polymer, methyl etherified melamine formaldehyde-1,2-propanediol polymer, methyl etherified melamine formaldehyde-1,4-butanediol polymer, methyl etherified melamine formaldehyde-polyester polyol polymer, methyl etherified melamine formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine formaldehyde-ethylene glycol polymer, butyl etherified melamine formaldehyde-1,2-propanediol polymer, butyl etherified melamine formaldehyde-1,4-butanediol polymer, butyl etherified melamine formaldehyde-polyester polyol polymer.

[0155] The etherified melamine aldehyde-polybasic acid polymer and its derivatives refer to the etherified melamine aldehyde resin and polybasic acid high-temperature cross-linking and curing reaction product. Optionally, the molar ratio of the etherified melamine aldehyde resin and the polybasic acid can be 1:2-1:6.

[0156] In some embodiments, the polycarboxylic acid can include one or more of a di-carboxylic acid, a tri-carboxylic acid, a tetra-carboxylic acid. Optionally, the polycarboxylic acid can include one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid. More optionally, the polycarboxylic acid can include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, terephthalic acid.

[0157] In some embodiments, the etherified melamine aldehyde-polycarboxylic acid polymer and its derivatives can include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malonic acid polymer, a methyl etherified melamine formaldehyde-succinic acid polymer, a methyl etherified melamine formaldehyde-citric acid polymer, a methyl etherified melamine formaldehyde-terephthalic acid polymer, a methyl etherified melamine formaldehyde-phthalic acid polymer, a butyl etherified melamine formaldehyde-oxalic acid polymer, a butyl etherified melamine formaldehyde-malonic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, a butyl etherified melamine formaldehyde-phthalic acid polymer.

[0158] The etherified melamine aldehyde-polycarboxylic acid polymer and its derivatives refer to the etherified melamine aldehyde resin and polycarboxylic acid high temperature cross-linking and curing reaction product. Optionally, the molar ratio of the etherified melamine aldehyde resin and polycarboxylic acid can be 1:2-1:6.

[0159] In some embodiments, the polycarboxylic acid can include one or more of a di-carboxylic acid, a tri-carboxylic acid, a tetra-carboxylic acid. Optionally, the polycarboxylic acid can include one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid. More optionally, the polycarboxylic acid can include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, terephthalic acid.

[0160] In some embodiments, the etherified melamine aldehyde-polycarboxylic acid polymer and its derivatives can include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malonic acid polymer, a methyl etherified melamine formaldehyde-succinic acid polymer, a methyl etherified melamine formaldehyde-citric acid polymer, a methyl etherified melamine formaldehyde-terephthalic acid polymer, a methyl etherified melamine formaldehyde-phthalic acid polymer, a butyl etherified melamine formaldehyde-oxalic acid polymer, a butyl etherified melamine formaldehyde-malonic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, a butyl etherified melamine formaldehyde-phthalic acid polymer.

[0161] In some embodiments, the polymer particles containing triazine ring structure units have no glass transition temperature below 300°C.

[0162] The polymer particles containing the triazine ring structural unit have no glass transition temperature below 300℃, indicating that the organic particles have good heat resistance and thermal stability, thereby better resisting thermal shrinkage of the porous base film, improving the heat resistance of the separation film, and improving the reliability of the secondary battery cell.

[0163] In some embodiments, the volume distribution particle size Dv50 of the polymer particles containing the triazine ring structural unit can be 200nm-820nm.

[0164] The volume distribution particle size Dv50 of the polymer particles containing the triazine ring structural unit in the above range is beneficial to the separation film having good heat resistance and air permeability.

[0165] In some embodiments, the cross-linked styrene-based organic particles can include styrene or styrene derivative structural units and cross-linking structural units. The cross-linking structural unit of the cross-linked styrene-based organic particles refers to a structural unit for connecting the styrene or styrene derivative structural unit.

[0166] In some embodiments, the styrene or styrene derivative structural unit can include one or more of a styrene structural unit, a 1-methyl-1-styrene structural unit, a 4-methylstyrene structural unit, a 2-methylstyrene structural unit, a 2,4-dimethylstyrene structural unit, and a 2,5-dimethylstyrene structural unit.

[0167] In some embodiments, the cross-linking structural unit can include one or more of a divinylbenzene structural unit, a diethylene glycol dimethacrylate structural unit, a pentaerythritol tetraacrylate structural unit, a 1,4-butanediol diacrylate structural unit, a 1,6-hexanediol diacrylate structural unit, a 1,8-octanediol diacrylate structural unit, a trimethylolpropane triacrylate structural unit, a pentaerythritol trimethacrylate structural unit, a tetraethylene glycol dimethacrylate structural unit, a tripropylene glycol diacrylate structural unit, an N,N-methylenebisacrylamide structural unit, an N,N'-vinylbisacrylamide structural unit, and a 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit.

[0168] In some embodiments, the cross-linked styrene-based organic particles have a glass transition temperature T g of 106℃-160℃.

[0169] The cross-linked styrene-based organic particles have a glass transition temperature T g of 106℃-160℃, have good heat resistance and thermal stability, thereby better resisting thermal shrinkage of the porous base film, improving the heat resistance of the separation film, and improving the reliability of the secondary battery cell.

[0170] In some embodiments, the volume distribution particle size Dv50 of the crosslinked styrene-based organic particles can be 85 nm to 320 nm.

[0171] The volume distribution particle size Dv50 of the crosslinked styrene-based organic particles in the above range is advantageous for the isolation film to have good heat resistance and air permeability.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] 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.

[0176] Optionally, the crosslinking structure units can include one or more of divinylbenzene structure units, diethylene glycol divinyl ether structure units, triethylene glycol divinyl ether structure units, maleic acid diallyl ester structure units, ethylene glycol dimethyl acrylate structure units, 1,4-butanediol diacrylate structure units, 1,6-hexanediol diacrylate structure units, 1,8-octanediol diacrylate structure units, trimethylolpropane triacrylate structure units, pentaerythritol trimethyl acrylate structure units, tetraethylene glycol dimethyl acrylate structure units, tripropylene glycol diacrylate structure units, 2,2,4-trimethyl adipic acid bis[2-ethylaziridine] structure units, 1,1-nonanedioic acid bis[2-methylaziridine] structure units, 1,1-(1,3-phenylenedicarbonyl) bis[2-methylaziridine] structure units, trimethylolpropane tris(2-methyl-1-aziridinyl propionate) structure units, trimethylolpropane-tris[3-(2-methylaziridinyl) propionate] structure units, pentaerythritol tris(3-aziridinyl) propionate structure units.

[0177] The raw material of the silicon-containing organic resin particles can include monomers and a crosslinking agent, the monomers can include silane coupling agents containing alkenyl and / or acryloxy groups. In some embodiments, the monomers can include vinyl silane coupling agents and / or acryloxy silane coupling agents. The crosslinking agent forms crosslinking structural units of the silicon-containing organic crosslinked resin particles after polymerization with the monomers. In some embodiments, the crosslinking agent can be a multifunctional crosslinking agent. Alternatively, 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-trimethyladipyl bis[2-ethylaziridine], 1,1-nonanedioyl 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.

[0178] In some embodiments, the silicon-containing organic resin particles have no glass transition temperature below 300°C.

[0179] The silicon-containing organic resin particles have no glass transition temperature below 300°C, which indicates that the silicon-containing organic resin 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.

[0180] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles can be 85 nm-320 nm.

[0181] The volume distribution particle size Dv50 of the silicon-containing organic resin particles in the above range is beneficial to the separator film having good heat resistance and air permeability.

[0182] 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.

[0183] Alternatively, 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%.

[0184] In some embodiments, the binder in the coating layer can include, but is not limited to, one or more of polyacrylate binders, nitrile rubber binders, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0185] In some embodiments, the coating layer can further include a dispersant, such as can include, but is not limited to, a polyacrylate 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.

[0186] In some embodiments, the separator film can further include polymer binder particles. The "polymer binder particles" function to improve the adhesion of the separator film to the pole piece in the separator film, and have substantially no high-temperature resistance.

[0187] In some embodiments, the polymer binder particles can be embedded in the organic particles and form protrusions on the surface of the coating layer.

[0188] 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 polymer binder particles are disposed in the bonding layer.

[0189] 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 polymer binder particles are disposed in the bonding layer.

[0190] In some embodiments, the average particle size of the polymer binder particles can be 6 μm to 18 μm.

[0191] 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 release film, randomly selecting a test sample with a length x width of 50 mm x 100 mm on the release film, randomly selecting multiple test areas (for example, 5) in the test sample, and reading the particle size of the particles to be measured in each test area under a certain magnification (for example, more than 500 times); counting the number and particle size value 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, multiple test samples (for example, 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 farthest points on the particles to be measured is taken as the particle size of the particles to be measured.

[0192] In some embodiments, the polymeric binder particles can include vinylidene fluoride-based polymeric particles, such as polyvinylidene fluoride (PVDF) particles and / or copolymer particles of vinylidene fluoride monomers and comonomers.

[0193] 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.

[0194] Optionally, the comonomer can include at least one of trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl) ether (such as perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether), perfluoro(1,3-dioxolane), and perfluoro(2,2-dimethyl-1,3-dioxolane).

[0195] In some embodiments, the thickness of the coating layer can be 0.5-5 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 0.5-4 μm, 0.5-3 μm, 0.5-2 μm, 0.6-4 μm, 0.6-3 μm, 0.6-2 μm, 0.8-4 μm, 0.8-3 μm, 0.8-2 μm.

[0196] In some embodiments, the areal density of the coating layer can be 0.45 g / m 2 -5 g / m 2 .

[0197] In some embodiments, the porous base film can comprise a film or nonwoven web selected from any one or at least two of the following: 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, polyvinyl naphthalene.

[0198] 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.

[0199] In some embodiments, the thickness of the porous base film can be 4-12 μm, optionally 4-9 μm.

[0200] In some embodiments, the porosity of the porous base film can be 25-60%, optionally 28-50%.

[0201] 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 1.1.

[0202] The volume distribution particle size Dv50 of the organic particles and the average pore size of the porous base film have the same unit, such as nm.

[0203] This can reduce the problem of plugging the pores and improve the air permeability and ion conductivity of the separation film.

[0204] In some embodiments, the average pore size of the porous base film can be 25-82 nm.

[0205] The average pore size of the porous base film can be tested by using a capillary porosimeter (bubble point method). An exemplary testing method is as follows: a circular sample with a diameter of 25 mm is taken and 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 pores of the sample to be tested, the pressure and flow rate of the press are inversely proportional to the pore size, and the average pore size of the sample to be tested is obtained by software sampling and pressure and pore size conversion analysis. The testing instrument can be a CFP 1500 pore size analyzer from PMI, and the testing pressure can be 100-350 psi.

[0206] In some embodiments, the thickness of the separation film can be 5-14 μm, optionally 5-12 μm, 6-12 μm. This is beneficial to improve the energy density of the secondary battery cell.

[0207] The glass transition temperature T gThe test can be carried out as follows: 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, purging 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. 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 .

[0208] The glass transition temperature Tg g refers to the transition temperature from a glassy state to a high-elastic state, which shows a step change on the DSC curve.

[0209] The organic particles have no glass transition temperature Tg below 300°C g refers to the fact that the DSC curve of the organic particles does not show a step change below 300°C.

[0210] Dv50 represents the particle size corresponding to the cumulative volume distribution percentage of 50%, which can be tested by a laser particle size analyzer according to GB / T 19077-2016. During the test, a clean small beaker is taken and 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; the laser particle size analyzer is turned on, the light path system is cleaned, and the background is automatically tested; the ultrasonically treated sample solution is stirred to make it uniformly dispersed, and then it is placed in the sample cell as required, and the particle size is measured. The test instrument can be a MasterSizer 3000 laser particle size analyzer.

[0211] 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.

[0212] The separation membrane can be prepared according to methods known in the art.

[0213] 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.

[0214] In some embodiments, the slurry can further include polymeric binder particles, and after drying of the slurry, the polymeric binder particles are embedded in the organic particles and form protrusions on the surface of the coating.

[0215] In some embodiments, the method for preparing the separation film can include: a step of coating a heat-resistant layer slurry including organic particles and a binder on at least one side of a porous base film, and drying to form a heat-resistant layer; and a step of coating a bonding layer slurry including polymer binder particles and a binder on at least a portion of the surface of the heat-resistant layer, and drying to obtain the separation film.

[0216] In some embodiments, the method for preparing the separation film can include: a step of coating a heat-resistant slurry including organic particles and a binder on one side of a porous base film, and coating a bonding layer slurry including polymer binder particles and a binder on at least a portion of the surface of the other side of the porous base film, and drying to obtain the separation film.

[0217] In some embodiments, the solvent of the slurry can be water, for example, deionized water.

[0218] In some embodiments, the slurry can further include other components, for example, can further include dispersants and / or wetting agents, etc.

[0219] The prior art generally uses magnets, magnetic rings, etc. to adsorb magnetic foreign particles in the organic particles. Although this method can reduce the magnetic foreign particles in the organic particles, the magnetic removal efficiency is low, and only simple adsorption of relatively large-sized magnetic foreign particles is possible, and often requires multiple repeated operations, which is relatively costly.

[0220] In view of this, the embodiments of the present disclosure provide a method for removing magnetic foreign particles from organic particles, which has high magnetic removal efficiency, good magnetic removal effect, and low cost.

[0221] The method for removing magnetic foreign particles includes the following steps: providing a slurry containing organic particles, and removing the magnetic foreign particles from the slurry by using an iron remover. The iron remover includes a pipeline for the slurry to flow and a plurality of magnetic rods arranged in the pipeline. The pipeline has an inlet pipe and an outlet pipe at two ends, respectively. One end of each magnetic rod extends into the pipeline, and the other end is connected to a driving mechanism. The magnetic field strength of each magnetic rod is greater than or equal to 12000GS. The diameter of each magnetic rod is 20mm-50mm. The spacing between adjacent magnetic rods is 0.1 times to 1.5 times the diameter of the magnetic rod. The organic particles are obtained.

[0222] The slurry containing organic particles is used to remove the magnetic foreign particles. The slurry can better disperse the organic particles, increasing the contact area with the magnetic rods, thereby better removing the magnetic foreign particles in the organic particles. The magnetic field strength of each magnetic rod is greater than or equal to 12000GS, thereby providing sufficient adsorption force on the magnetic foreign particles in the slurry, thereby effectively reducing the content of small-sized magnetic foreign particles. The diameter of each magnetic rod is 20mm-50mm, and the spacing between adjacent magnetic rods is 0.1 times to 1.5 times the diameter of the magnetic rod, thereby making the magnetic field in the iron remover uniform and stable, thereby improving the magnetic removal efficiency and reducing the loss of raw materials.

[0223] Therefore, the method for removing magnetic particles provided by the embodiments of the present disclosure has the advantages of high removal efficiency, good removal effect and low cost, and can also reduce the loss of raw materials while effectively removing the magnetic particles.

[0224] In some embodiments, the slurry after the magnetic removal treatment can be directly used to prepare the coating slurry of the isolation film, or can be dried and then mixed with other components to prepare the coating slurry of the isolation film.

[0225] In some embodiments, the arrangement of the magnetic rods can be multi-layer magnetic rods arranged alternately.

[0226] This arrangement can improve the magnetic removal effect of the magnetic rods on the surface layer flow and the bottom layer flow slurry. By arranging the magnetic rods alternately in high and low positions, the magnetic impurity particles in different layers of the slurry can be effectively adsorbed and removed.

[0227] In some embodiments, the pipe diameter can be greater than or equal to DN50.

[0228] In some embodiments, the viscosity of the slurry containing organic particles at 25°C can be 2.5-5000 mpa.s, optionally 2.5-1000 mpa.s, 2.5-800 mpa.s, 2.5-600 mpa.s.

[0229] In some embodiments, the solid content of the slurry containing organic particles can be 5%-50%, optionally 10%-40%, 15%-35%.

[0230] The slurry containing organic particles can use the slurry system obtained after the reaction of the organic particles, or the dried prepared organic particles can be mixed with water to obtain the slurry.

[0231] The viscosity of the slurry can be tested according to GB / T 10247-2008. The testing equipment can use a DV-2TLV viscometer.

[0232] The solid content of the slurry can be tested as follows: take a certain amount of slurry sample, denoted as m1; adjust the oven temperature to 105°C, and then dry until the sample mass no longer changes, at which time the sample mass is denoted as m2; the solid content of the slurry = (m1-m2) / m1x100%.

[0233] The organic particles can include one or more of phenolic resin organic particles, polymer particles containing triazine ring structure units, cross-linked styrene organic particles, and silicon-containing organic resin particles.

[0234] The embodiments of the present disclosure also provide a method for preparing phenolic resin organic particles.

[0235] In some embodiments, the method for preparing the phenolic resin-based organic particles comprises the following steps: providing a resol phenolic resin-based material; curing the resol phenolic resin-based material at a first temperature and in a first atmosphere for a first time, and then curing the resol phenolic resin-based material at a second temperature and in a second atmosphere for a second time, and then crushing to obtain resol phenolic resin-based organic particles to be removed of magnetism, the first temperature being 90-180°C, and the second temperature being 190-290°C; mixing the resol phenolic resin-based organic particles to be removed of magnetism with water to obtain a slurry, and removing magnetic foreign particles from the slurry by passing the slurry through an iron remover, the iron remover comprising a pipeline for the slurry to flow and a plurality of magnetic rods arranged in the pipeline, the pipeline having an inlet pipe and an outlet pipe at two ends thereof, one end of each magnetic rod extending into the pipeline and the other end being connected to a driving mechanism, the magnetic field strength of each magnetic rod being greater than or equal to 12000GS, the diameter of each magnetic rod being 20-50mm, and the distance between adjacent magnetic rods being 0.1-1.5 times the diameter of the magnetic rods, to obtain the resol phenolic resin-based organic particles.

[0236] The resol phenolic resin-based organic particles obtained by the above method can have both low content of magnetic foreign particles and good heat resistance.

[0237] The resol phenolic resin-based organic particles prepared by the present disclosure are thermosetting resite polymers.

[0238] The first temperature is 90-180°C, for example, 90°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, 180°C, or a range formed by any of the above values.

[0239] The first temperature is within the above range, which can make the curing of the resol phenolic resin-based material in the first stage more uniform and sufficient, so that the resol phenolic resin-based organic particles obtained thereby have better heat resistance.

[0240] The second temperature is 190-290°C, for example, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, or a range formed by any of the above values.

[0241] The second temperature is within the above range, which can make the curing of the resol phenolic resin-based organic particles more sufficient and the resol phenolic resin-based organic particles have better heat resistance while avoiding denaturation (such as degradation) of the resol phenolic resin-based organic particles.

[0242] Optionally, the first temperature can be 90-180°C, 100-180°C, 110-180°C, 100-165°C, 110-165°C.

[0243] Optionally, the second temperature can be 200-290°C, 200-285°C.

[0244] In some embodiments, the first time can be 1-5h, for example, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or a range consisting of any of the aforementioned values.

[0245] The first time in the above range can make the curing of the resol resin-based material in the first stage more uniform and sufficient, so that the phenolic resin-based organic particles with better heat resistance can be obtained.

[0246] In some embodiments, the second time can be 1-6h, for example, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.2h, 5.4h, 5.6h, 5.8h, 6h, or a range consisting of any of the aforementioned values.

[0247] The second time in the above range can make the curing of the phenolic resin-based organic particles more sufficient and the particles have better heat resistance.

[0248] In some embodiments, the first atmosphere can be an inert gas atmosphere or an oxygen-containing atmosphere. The oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5-50%. Optionally, the inert gas can include, but is not limited to, one or more of nitrogen, argon, and helium.

[0249] Optionally, the first atmosphere is an oxygen-containing atmosphere, and the volume fraction of oxygen in the oxygen-containing atmosphere can be 10-30%. More optionally, the first atmosphere can be an air atmosphere.

[0250] In some embodiments, the second atmosphere can be an inert gas atmosphere or an oxygen-containing atmosphere. The oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5-50%. Optionally, the inert gas can include, but is not limited to, one or more of nitrogen, argon, and helium.

[0251] Optionally, the second atmosphere is an oxygen-containing atmosphere, and the volume fraction of oxygen in the oxygen-containing atmosphere can be 10% to 30%. More optionally, the second atmosphere can be an air atmosphere.

[0252] The resol resin material can be commercially available or synthesized according to a method known in the art. In some embodiments, the method for preparing the resol resin material comprises the following steps: reacting a phenolic compound and an aldehyde compound under catalysis of an alkaline substance to obtain the resol resin material.

[0253] Optionally, the alkaline substance can include one or more of ammonia, NaOH, and Na2CO3.

[0254] Optionally, the phenolic compound can include one or more of phenol, p-dihydroxybenzene, m-dihydroxybenzene, o-dihydroxybenzene, cresol, and cardanol.

[0255] Optionally, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propyl aldehyde, n-butyl aldehyde, glyoxal, and furfural.

[0256] The embodiments of the present disclosure also provide a method for preparing polymer particles containing triazine ring structure units.

[0257] In some embodiments, the method for preparing the polymer particles containing triazine ring structure units comprises the following steps: providing a precursor containing a triazine ring structure; heating and curing the precursor containing the triazine ring structure under an oxygen-containing atmosphere, and then crushing to obtain polymer particles containing triazine ring structure units to be removed of magnetism, the heating and curing temperature being 180°C to 290°C; mixing the polymer particles containing triazine ring structure units to be removed of magnetism with water to obtain a slurry, and removing magnetic foreign particle through an iron remover, the iron remover comprising a pipeline for the slurry to flow and a plurality of magnetic rods arranged in the pipeline, the pipeline having an inlet pipe and an outlet pipe at two ends respectively, one end of each magnetic rod extending into the pipeline and the other end being connected to a driving mechanism, the magnetic field strength of each magnetic rod being greater than or equal to 12000GS, the diameter of each magnetic rod being 20mm to 50mm, and the spacing between adjacent magnetic rods being 0.1 times to 1.5 times the diameter of the magnetic rod, to obtain the polymer particles containing triazine ring structure units.

[0258] The polymer particles containing triazine ring structure units obtained by the above preparation method can have both low magnetic foreign particle content and good heat resistance.

[0259] The temperature for heat curing can be in a range from 180 °C to 290 °C, for example, 180 °C, 185 °C, 190 °C, 195 °C, 200 °C, 205 °C, 210 °C, 215 °C, 220 °C, 225 °C, 230 °C, 235 °C, 240 °C, 245 °C, 250 °C, 255 °C, 260 °C, 265 °C, 270 °C, 275 °C, 280 °C, 285 °C, 290 °C, or a range defined by any two of the above values.

[0260] The temperature for heat curing in the above range is beneficial for the formation of the polymer particles containing triazine ring structure units from the resol resin containing triazine ring structure.

[0261] Optionally, the temperature for heat curing can be in a range from 205 °C to 285 °C, 215 °C to 285 °C, 225 °C to 285 °C, 20 °C to 285 °C, 205 °C to 280 °C, 215 °C to 280 °C, 225 °C to 280 °C, 20 °C to 280 °C.

[0262] In some embodiments, the time for heat curing can be in a range from 1 h to 8 h, for example, 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, 4.2 h, 4.4 h, 4.6 h, 4.8 h, 5 h, 5.2 h, 5.4 h, 5.6 h, 5.8 h, 6 h, 6.2 h, 6.4 h, 6.6 h, 6.8 h, 7 h, 7.2 h, 7.4 h, 7.6 h, 7.8 h, 8 h, or a range defined by any two of the above values.

[0263] The time for heat curing in the above range is beneficial for the formation of the polymer particles containing triazine ring structure units from the resol resin containing triazine ring structure.

[0264] Optionally, the time for heat curing can be in a range from 2 h to 7 h, 2.4 h to 7 h, 2.8 h to 7 h, 2 h to 6.6 h, 2.4 h to 6.6 h, 2.8 h to 6.6 h.

[0265] In some embodiments, the oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the inert gas can include, but is not limited to, one or more of nitrogen, argon, helium. In some embodiments, the volume fraction of oxygen in the oxygen-containing atmosphere can be in a range from 5% to 50%. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be in a range from 10% to 30%. More optionally, the oxygen-containing atmosphere can be an air atmosphere.

[0266] In some embodiments, the precursor containing a triazine ring structure can include at least one of a melamine formaldehyde resin, an etherified melamine formaldehyde resin, a mixture of the etherified melamine formaldehyde resin and at least one of a polyol, a polycarboxylic acid, a polyamide.

[0267] In some embodiments, the precursor containing a triazine ring structure can include a melamine formaldehyde resin, which can be obtained by reacting an aldehyde compound and an amine-substituted triazine compound, which can include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 1.75:1-3:1, such as 1.75:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, or a range formed by any of the above values. 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.

[0268] In some embodiments, the precursor containing a triazine ring structure can include an etherified melamine formaldehyde resin, which can be obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound, which can include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 4:1-7:1, such as 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, or a range formed by any of the above values. More optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 5:1-7:1, 5.5:1-7:1, 6:1-7:1, 6.5:1-7:1.

[0269] In some embodiments, the precursor containing a triazine ring structure includes a mixture of an etherified melamine formaldehyde resin and a polyol, and the molar ratio of the etherified melamine formaldehyde resin to the polyol can be 1:2-1:6.

[0270] In some embodiments, the precursor containing a triazine ring structure includes a mixture of an etherified melamine formaldehyde resin and a polycarboxylic acid, and the molar ratio of the etherified melamine formaldehyde resin to the polycarboxylic acid can be 1:2-1:6.

[0271] In some embodiments, the precursor containing a triazine ring structure includes a mixture of an etherified melamine formaldehyde resin and a polyamide, and the molar ratio of the etherified melamine formaldehyde resin to the polyamide can be 1:2-1:6.

[0272] In some embodiments, the alcohol compound forming the etherified melamine formaldehyde resin can include one or more of methanol, ethanol, butanol.

[0273] In some embodiments, the aldehyde compound forming the melamine formaldehyde resin and the etherified melamine formaldehyde resin can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0274] In some embodiments, the amine-substituted triazine compound forming the melamine formaldehyde resin and the etherified melamine formaldehyde resin can include one or more of the following general compounds, 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.

[0275] 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.

[0276] More optionally, 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.

[0277] The etherified melamine aldehyde resin can include one or more of a partially etherified melamine aldehyde resin, a fully etherified melamine aldehyde resin. Optionally, the etherified melamine aldehyde resin can include a fully etherified melamine aldehyde resin.

[0278] In some embodiments, the etherified melamine aldehyde resin can include one or more of a methyl etherified melamine aldehyde resin, an ethyl etherified melamine aldehyde resin, a butyl etherified melamine aldehyde resin, a methyl-butyl mixed etherified melamine aldehyde resin.

[0279] Optionally, the etherified melamine aldehyde resin can include one or more of a methyl etherified melamine formaldehyde resin, a butyl etherified melamine formaldehyde resin, a methyl etherified benzoguanamine formaldehyde resin, a butyl etherified benzoguanamine formaldehyde resin.

[0280] In some embodiments, the etherified melamine aldehyde resin can be in a liquid state.

[0281] The present disclosure also provides a method for preparing the crosslinked styrene-based organic particles.

[0282] In some embodiments, the method for preparing the crosslinked styrene-based organic particles includes the following steps: providing a pre-emulsion containing monomers, a crosslinking agent, an emulsifier, an initiator, and water, the monomers including one or more of styrene and derivatives thereof, the mass fraction of the crosslinking agent being 4%-40% based on the total mass of the monomers and the crosslinking agent being 100%; performing an emulsion polymerization reaction under the conditions of heating, inert gas protection, and stirring; removing magnetic foreign particle by passing the slurry obtained from the emulsion polymerization reaction through a de-ironer, the de-ironer including a pipeline for the slurry to flow and a plurality of magnetic rods arranged in the pipeline, the pipeline having an inlet pipe and an outlet pipe at two ends thereof, one end of each magnetic rod extending into the pipeline and the other end being connected to a driving mechanism, the magnetic field strength of each magnetic rod being greater than or equal to 12000GS, the diameter of each magnetic rod being 20mm-50mm, and the spacing between adjacent magnetic rods being 0.1 times-1.5 times the diameter of the magnetic rod, to obtain the crosslinked styrene-based organic particles.

[0283] The crosslinked styrene-based organic particles obtained by the above preparation method can have both low magnetic foreign particle content and good heat resistance.

[0284] The mass fraction of the crosslinking agent can be 4% to 40%, for example, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34%, 36%, 38%, 40%, or a range formed by any of the above values, based on the total mass of the monomer and the crosslinking agent being 100%.

[0285] The mass fraction of the crosslinking agent in the above range can improve the heat resistance of the crosslinked styrene-based organic particles.

[0286] Alternatively, the mass fraction of the crosslinking agent can be 5% to 40%, 8% to 40%, 8% to 30%, based on the total mass of the monomer and the crosslinking agent being 100%.

[0287] In some embodiments, the ripening temperature of the emulsion polymerization reaction can be 75°C to 90°C, for example, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C, 90°C, or a range formed by any of the above values.

[0288] In some embodiments, the ripening time of the emulsion polymerization reaction can be 1h to 4.5h, for example, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.5h, or a range formed by any of the above values.

[0289] In some embodiments, the emulsion polymerization reaction can include the following steps: under the conditions of a first heating temperature, inert gas protection and stirring, the pre-emulsion is added dropwise into a reactor containing water, and after a first time, the temperature is raised to a ripening temperature for ripening reaction, to obtain crosslinked styrene-based organic particles.

[0290] Alternatively, the first heating temperature can be 55°C to 70°C.

[0291] Alternatively, the first time can be 3h to 6h.

[0292] In some embodiments, the monomer can include one or more of styrene, 1-methyl-1-phenylethylene, 4-methylphenylethylene, 2-methylphenylethylene, 2,4-dimethylphenylethylene, 2,5-dimethylphenylethylene.

[0293] The crosslinking agent forms a crosslinking structural 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, tris allyl isocyanurate.

[0294] Optionally, the crosslinking agent can include one or more of divinylbenzene, N,N-methylenebisacrylamide, N,N'-vinylbisacrylamide.

[0295] 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.

[0296] 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.

[0297] In some embodiments, the mass fraction of the emulsifier can be 0.1%-4%, based on 100% of the total mass of the monomers and the crosslinking agent.

[0298] 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, azobisdimethylaminoformamide hydrochloride, azobisdimethylaminoformamide hydrochloride, azobisdimethylaminoformamide.

[0299] The present disclosure also provides a method for preparing silicon-containing organic resin particles.

[0300] 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, wherein the monomers comprise a silane coupling agent containing an alkenyl group and / or an acryloyloxy group, and the mass fraction of the crosslinking agent is 3-18% based on the total mass of the monomers and the crosslinking agent being 100%; performing an emulsion polymerization reaction under the conditions of heating, inert gas protection, and stirring; removing magnetic foreign particle by passing the slurry obtained from the emulsion polymerization reaction through a de-ironing device, wherein the de-ironing device comprises a pipeline for the slurry to flow and a plurality of magnetic rods arranged in the pipeline, the pipeline has an inlet pipe and an outlet pipe at two ends respectively, one end of the magnetic rod extends into the pipeline, and the other end is connected to a driving mechanism, the magnetic field strength of each magnetic rod is greater than or equal to 12000GS, the diameter of each magnetic rod is 20-50mm, the spacing between adjacent magnetic rods is 0.1-1.5 times the diameter of the magnetic rod, and the silicon-containing organic resin particles are obtained.

[0301] The silicon-containing organic resin particles obtained by the above preparation method can have low magnetic foreign particle content and good heat resistance.

[0302] The mass fraction of the crosslinking agent is 3-18% based on the total mass of the monomers and the crosslinking agent being 100%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, or a range composed of any of the above values.

[0303] The mass fraction of the crosslinking agent in the above range can improve the heat resistance of the silicon-containing organic resin particles.

[0304] Alternatively, the mass fraction of the crosslinking agent can be 5-15% based on the total mass of the monomers and the crosslinking agent being 100%.

[0305] The crosslinking agent forms a crosslinking structure unit of the silicon-containing organic crosslinked resin particles after polymerization with the monomers.

[0306] In some embodiments, the crosslinking agent can be a multi-functional crosslinking agent.

[0307] 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.

[0308] In some embodiments, the monomer can include a vinyl silane coupling agent and / or an acryloxy silane coupling agent.

[0309] 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, methacryloxypropyldimethylmethoxysilane, (3-acryloxy)dimethylmethoxysilane, 3- methacryloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyl dimethylethoxysilane, methylethyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylethyldimethoxysilane, 3-(methacryloxy)propylmethyldiethoxysilane.

[0310] In some embodiments, the monomer can include a first monomer and a second monomer.

[0311] 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.

[0312] 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.

[0313] 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.

[0314] 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.

[0315] 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.

[0316] In some embodiments, the heating temperature of the maturation stage of the emulsion polymerization reaction can be 75-92℃, for example, can be 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, or a range consisting of any of the aforementioned values.

[0317] In some embodiments, the heating time of the maturation stage of the emulsion polymerization reaction can be 1-5h, for example, can be 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or a range consisting of any of the aforementioned values.

[0318] In some embodiments, the emulsion polymerization reaction can comprise the following steps: under the conditions of the second heating temperature, inert gas protection and stirring, the pre-emulsion is added dropwise into the reactor containing water, after reacting for a second time, the temperature is raised to the heating temperature of the maturation stage to carry out the maturation reaction, and the silicon-containing organic resin particles are obtained.

[0319] Optionally, the second heating temperature can be 55-70℃.

[0320] Optionally, the second time can be 3-6h.

[0321] In some embodiments, the pre-emulsion can further comprise a pH adjuster. Optionally, the pH adjuster can include, but is not limited to, one or more of sodium bicarbonate, sodium hydroxide, ammonia water, etc.

[0322] The embodiments of the present disclosure also provide a secondary battery cell. The secondary battery cell comprises the separator film provided by the embodiments of the present disclosure. Thus, the secondary battery cell can have high quality energy density, high reliability and good long-term cycle stability.

[0323] The secondary battery cell further comprises a positive electrode sheet, a negative electrode sheet and an electrolyte, and the separator film is arranged between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the separator film and the negative electrode sheet can form an electrode assembly through a rolling process and / or a stacking process.

[0324] The secondary battery cell provided by the present disclosure can include, but is not limited to, a lithium battery cell, a sodium battery cell, etc. The composition of the positive electrode sheet, the negative electrode sheet and the electrolyte will be different for different types of secondary battery cells.

[0325] [Positive electrode sheet]

[0326] In some embodiments, the positive electrode tab can include a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector and including a positive electrode active material. For example, the positive electrode current collector has two surfaces opposite in the thickness direction of the positive electrode current collector, and the positive electrode film layer is disposed on either one or both of the two opposite surfaces of the positive electrode current collector.

[0327] As an example, the positive electrode 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 electrode 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 and modified compounds thereof, 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.

[0328] As an example, the positive electrode 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 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.1 Al 0.05one or more of O2, LiFePO4, LiMnPO4.

[0329] The secondary battery cell will be accompanied by Li de-intercalation and consumption during charging and discharging process, and the molar content of Li is different when the secondary battery cell is discharged to different states. In the enumeration of the positive electrode active material in the present disclosure, the molar content of Li is the initial state of the material, i.e. the state before feeding, and the positive electrode active material is applied to the secondary battery cell, and after charging and discharging cycle, the molar content of Li will change. In the enumeration of the positive electrode active material in the present disclosure, the molar content of O is only the theoretical state value, and the lattice oxygen release will cause the change of the molar content of O, and the actual molar content of O will also appear floating.

[0330] Taking a sodium battery cell as an example, the positive electrode active material can include but is not limited to one or more of sodium-containing transition metal oxides, polyanion materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), prussian blue type materials. As an example, the positive electrode active material can include but is not limited to one or more of NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, prussian blue type material, material of general formula X p M’ q (PO4) r O x Y 3-x . In the general formula X p M’ q (PO4) r O x Y 3-x , 0 < p < 4, 0 < q < 2, 1 < r < 3, 0 < x < 2, X includes but is not limited to one or more of H + , Li + , Na + , K + and NH4 + , M' is a transition metal cation, which can optionally include but is not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, which can optionally be one or more of F, Cl and Br.

[0331] The modifying compound of the positive electrode active material of each of the lithium battery cell and the sodium battery cell described above can be a doping modification and / or a surface coating modification to the positive electrode active material.

[0332] In some embodiments, the positive electrode film layer can further include a positive electrode conductive agent. As an example, the positive electrode conductive agent can include, but is not limited to, one or more of super-p carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0333] In some embodiments, the positive electrode film layer can further include a positive electrode binder. As an example, the positive electrode binder can include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylic resin.

[0334] In some embodiments, the positive electrode current collector can employ a metal foil or a composite current collector. As an example of the metal foil, an aluminum foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0335] The positive electrode film layer is generally formed by coating a positive electrode slurry on a positive electrode current collector, drying, and cold-pressing. The positive electrode slurry is generally formed by dispersing and uniformly stirring a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and any other components in a solvent. The solvent can be N-methyl pyrrolidone (NMP), but is not limited thereto.

[0336] [Negative electrode tab]

[0337] 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 itself, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.

[0338] The negative active material can employ materials known in the art that are useful for secondary battery cells. As an example, the negative 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.

[0339] 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.

[0340] 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).

[0341] 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.

[0342] In some embodiments, the negative electrode current collector can employ a metal foil or a composite current collector. As an example of a 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.

[0343] The negative electrode film layer is typically formed by coating a negative electrode slurry on a negative electrode current collector, drying, and cold-pressing. The negative electrode slurry is typically formed by dispersing and uniformly stirring the negative active material, the negative electrode conductive agent, the negative electrode binder, and other optional auxiliary agents in a solvent. The solvent can be N-methyl pyrrolidone (NMP) or deionized water, but is not limited thereto.

[0344] 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 also includes a conductive primer layer (e.g., composed of a conductive agent and a binder) sandwiched between the negative electrode current collector and the negative electrode film layer, disposed on the surface of the negative electrode current collector.

[0345] In some embodiments, the negative electrode tab can employ 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.

[0346] [Electrolyte]

[0347] The electrolyte plays a role in conducting ions between the positive electrode tab and the negative electrode tab.

[0348] In some embodiments, the electrolyte employs an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0349] 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).

[0350] 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).

[0351] 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.

[0352] 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.

[0353] Optionally, the additive can include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propane sultone (PS), and vinyl sulfate (DTD).

[0354] 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.

[0355] Embodiments

[0356] 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.

[0357] A commercially available phenol and formaldehyde-based resol resin material was placed in a curing oven, the atmosphere was set to air atmosphere, the temperature was set to 155°C, and the temperature was maintained for 3 hours. After the end, the temperature of the curing oven was increased to 230°C, and the temperature was maintained for 3 hours. After the end of the two curing, the cured phenol formaldehyde resin material was taken out, placed in the air and naturally cooled, then crushed, sand ground, sieved, then prepared into a slurry with a solid content of 15% and a viscosity of 200 mpa.s with deionized water, and made it pass through the iron remover uniformly, the magnetic field strength of the magnetic bar in the iron remover was 12000GS, the diameter of the magnetic bar was 35mm, the distance between the magnetic bars was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0mm, and the phenol formaldehyde resin organic particle 1-1# slurry was obtained after the end.

[0358] A commercially available phenol and formaldehyde-based resol resin material was placed in a curing oven, the atmosphere was set to air atmosphere, the temperature was set to 155°C, and the temperature was maintained for 3 hours. After the end, the temperature of the curing oven was increased to 230°C, and the temperature was maintained for 3 hours. After the end of the two curing, the cured phenol formaldehyde resin material was taken out, placed in the air and naturally cooled, then crushed, sand ground, sieved, then prepared into a slurry with a solid content of 15% and a viscosity of 400 mpa.s with deionized water, and made it pass through the iron remover uniformly, the magnetic field strength of the magnetic bar in the iron remover was 12000GS, the diameter of the magnetic bar was 35mm, the distance between the magnetic bars was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0mm, and the phenol formaldehyde resin organic particle 1-2# slurry was obtained after the end.

[0359] A commercially available phenol and formaldehyde-based resol resin material was placed in a curing oven, the atmosphere was set to air atmosphere, the temperature was set to 155°C, and the temperature was maintained for 3 hours. After the end, the temperature of the curing oven was increased to 230°C, and the temperature was maintained for 3 hours. After the end of the two curing, the cured phenol formaldehyde resin material was taken out, placed in the air and naturally cooled, then crushed, sand ground, sieved, then prepared into a slurry with a solid content of 15% and a viscosity of 200 mpa.s with deionized water, and made it pass through the iron remover uniformly, the magnetic field strength of the magnetic bar in the iron remover was 12000GS, the diameter of the magnetic bar was 35mm, the distance between the magnetic bars was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0mm, and the phenol formaldehyde resin organic particle 1-3# slurry was obtained after the end.

[0360] The phenol-formaldehyde resin material with phenol and formaldehyde as raw materials was placed in a curing oven, the atmosphere was set to air atmosphere, the temperature was set to 155°C, and the temperature was kept for 3h. After the end of the curing, the temperature of the curing oven was increased to 230°C, and the temperature was kept for 3h. After the end of the two curing, the cured phenol-formaldehyde resin material was taken out, placed in air for natural cooling, then crushed, sand ground, sieved, and then prepared into a slurry with a solid content of 20% and a viscosity of 200mpa.s using deionized water, and the slurry was uniformly passed through an iron remover. The magnetic field strength of the magnetic rod in the iron remover was 12000GS, the diameter of the magnetic rod was 35mm, the distance between the magnetic rods was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the slurry flowing through the magnetic rod was DN50, and the gap between the pipe and the magnetic rod was 10.0mm. After the end of the test, the phenol-formaldehyde resin organic particle 1-4# slurry was obtained.

[0361] The phenol-formaldehyde resin material with phenol and formaldehyde as raw materials was placed in a curing oven, the atmosphere was set to air atmosphere, the temperature was set to 155°C, and the temperature was kept for 3h. After the end of the curing, the cured phenol-formaldehyde resin material was taken out, placed in air for natural cooling, then crushed, sand ground, sieved, and then prepared into a slurry with a solid content of 20% and a viscosity of 200mpa.s using deionized water, and the slurry was uniformly passed through an iron remover. The magnetic field strength of the magnetic rod in the iron remover was 12000GS, the diameter of the magnetic rod was 35mm, the distance between the magnetic rods was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the slurry flowing through the magnetic rod was DN50, and the gap between the pipe and the magnetic rod was 10.0mm. After the end of the test, the phenol-formaldehyde resin organic particle 1-4# slurry was obtained.

[0362] Performance test of organic particles

[0363] (1) Glass transition temperature T of organic particles g Test

[0364] An appropriate amount of sample (e.g. 5mg-15mg) was placed in a differential scanning calorimeter (DSC) crucible, shaken to level, and covered with a crucible cover. The parameter settings were: nitrogen atmosphere, purging gas 60mL / min, and protective gas 20mL / min. The program settings were: temperature increased from 25°C to 200°C at a rate of 10°C / min, kept for 5min to eliminate thermal history, then temperature decreased from 200°C to -40°C at a rate of 10°C / min, and then temperature increased from -40°C to 300°C at a rate of 10°C / min. The glass transition temperature T of the organic particles was obtained by the DSC curve. g or determine whether the organic particles have a glass transition temperature T g .

[0365] (2) Melting point test of organic particles

[0366] 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, purging 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. Determine whether the organic particles have a melting point by the DSC curve.

[0367] The organic particles 1-1# to 1-4# prepared above meet the following characteristics: the phenolic resin-based organic particles are thermosetting resol polymers, which have no melting point, no glass transition temperature T g .

[0368] Next, the organic particles prepared above are used in the separator film to verify their effect on the performance of the separator film and the secondary battery cell.

[0369] The separator film preparation process is as follows.

[0370] A commercially available polyethylene microporous film with a thickness of 7 μm is used as the porous base film; the organic particles prepared above, the dispersant sodium carboxymethyl cellulose, and the binder polyacrylate are mixed uniformly in deionized water at a solid mass ratio of 90:2:8 to obtain a slurry; the slurry is uniformly coated on both surfaces of the porous base film, and the solvent is removed by drying to obtain a separator film. The coating thickness is 1.5 μm, and the thickness of the separator film is 10 μm.

[0371] The preparation process of the secondary battery cell is as follows.

[0372] The positive electrode active material LiFePO4, the positive electrode binder polyvinylidene fluoride (PVDF), and the positive electrode conductive agent carbon black are added to N-methyl pyrrolidone (NMP) at a mass ratio of 97:2:1, and a positive electrode slurry is prepared after being fully stirred and mixed uniformly; the positive electrode slurry is uniformly coated on the positive electrode current collector aluminum foil, and then dried, cold-pressed, and cut to obtain a positive electrode sheet.

[0373] 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 are added to deionized water at a mass ratio of 96.0:1.4:1.5:1.1, and a negative electrode slurry is prepared after being fully stirred and mixed uniformly; the negative electrode slurry is uniformly coated on the negative electrode current collector copper foil, and then dried, cold-pressed, and cut to obtain a negative electrode sheet.

[0374] The ethylene carbonate (EC) and the methyl ethyl carbonate (EMC) were mixed at a volume ratio of 3:7 to obtain a mixed solvent at 25°C, and then LiPF6 and vinylene carbonate (VC) were dissolved in the mixed solvent to obtain an electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of VC was 3% based on the mass of the electrolyte.

[0375] The positive electrode sheet, the separator, and the negative electrode sheet were stacked in sequence and wound and hot-pressed to obtain an electrode assembly, and then the electrode assembly was packaged in an aluminum plastic film by top side sealing, and then the processes of injecting electrolyte, standing, formation, aging, degassing, and second sealing were performed to obtain a soft package secondary battery cell.

[0376] Performance test

[0377] (1) K value test

[0378] The secondary battery cell with an initial voltage of 3.8 V was placed in an environment of 45°C for 24 h, and then placed in an environment of 25°C for 24 h, and the voltage OCV1 of the secondary battery cell at this time was tested. Then the secondary battery cell was continuously placed in an environment of 25°C for 48 h, and the voltage OCV2 of the secondary battery cell at this time was tested. The K value (mV / h) = (OCV1-OCV2) / 48.

[0379] (2) Cycle performance test of the secondary battery cell

[0380] The secondary battery cell was charged at 1 / 3C constant current to 3.8 V, and then charged at 3.8 V constant voltage to a current of 0.05C, and then rested for 5 min, and then discharged at 1 / 3C constant current to 2 V at 25°C, and the obtained discharge capacity was recorded as the initial capacity Co; the above charging and discharging steps were repeated, and the discharge capacity Cn of the secondary battery cell after the nth cycle was recorded at the same time, and then the capacity retention rate Pn of the secondary battery cell after each cycle was calculated as (Cn / Co) x 100%. The cycle performance difference of the secondary battery cell can be reflected by the capacity retention rate of the secondary battery cell after 500 cycles.

[0381] Table 1

[0382] From the above test results, it can be seen that the phenolic resin organic particles with low magnetic foreign particle content prepared in the embodiments of the present disclosure can reduce the self-discharge of the secondary battery cell and improve the cycle performance of the secondary battery cell.

[0383] Next, the phenolic resin organic particles were replaced with polymer particles containing triazine ring structure units.

[0384] Melamine, benzoguanamine, formaldehyde were reacted in alkaline environment with pH of 8.6±0.1 to obtain a melem resin containing triazine ring structure. The mass ratio of melamine to benzoguanamine was 99:1, and the ratio of the total moles of melamine and benzoguanamine to the moles of formaldehyde was 1:2.45. The melem resin containing triazine ring structure was cured in air atmosphere at 220℃ for 4h, and then was crushed, sand ground, sieved, and then was prepared into a slurry with solid content of 15% and viscosity of 300mpa.s using deionized water, and was made to pass through an iron remover uniformly, the magnetic field strength of the magnetic bar in the iron remover was 12000GS, the diameter of the magnetic bar was 35mm, the distance between the magnetic bars was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the pipe through which the slurry flowed through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0mm, to obtain a polymer particle slurry 2-1# containing triazine ring structure units.

[0385] Melamine, benzoguanamine, formaldehyde were reacted in alkaline environment with pH of 8.6±0.1 to obtain a melem resin containing triazine ring structure. The mass ratio of melamine to benzoguanamine was 99:1, and the ratio of the total moles of melamine and benzoguanamine to the moles of formaldehyde was 1:2.45. The melem resin containing triazine ring structure was cured in air atmosphere at 220℃ for 4h, and then was crushed, sand ground, sieved, and then was prepared into a slurry with solid content of 15% and viscosity of 600mpa.s using deionized water, and was made to pass through an iron remover uniformly, the magnetic field strength of the magnetic bar in the iron remover was 12000GS, the diameter of the magnetic bar was 35mm, the distance between the magnetic bars was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the pipe through which the slurry flowed through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0mm, to obtain a polymer particle slurry 2-2# containing triazine ring structure units.

[0386] Melamine, benzoguanamine, formaldehyde were reacted in alkaline environment with pH of 8.6±0.1 to obtain a melem resin containing triazine ring structure. The mass ratio of melamine to benzoguanamine was 99:1, and the ratio of the total moles of melamine and benzoguanamine to the moles of formaldehyde was 1:2.45. The melem resin containing triazine ring structure was cured in air atmosphere at 220℃ for 4h, and then was crushed, sand ground, sieved, and then was prepared into a slurry with solid content of 15% and viscosity of 300mpa.s using deionized water, and was made to pass through an iron remover uniformly, the magnetic field strength of the magnetic bar in the iron remover was 12000GS, the diameter of the magnetic bar was 25mm, the distance between the magnetic bars was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the pipe through which the slurry flowed through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0mm, to obtain a polymer particle slurry 2-3# containing triazine ring structure units.

[0387] Melamine, benzoguanamine, formaldehyde were reacted in an alkaline environment with a pH of 8.6±0.1 to obtain a melem resin containing a triazine ring structure. The mass ratio of melamine to benzoguanamine was 99:1, and the ratio of the total number of moles of melamine and benzoguanamine to the number of moles of formaldehyde was 1:2.45. The melem resin containing a triazine ring structure was cured in an air atmosphere at 220℃ for 4h, and then crushed, sand milled, and sieved. A slurry with a solid content of 25% and a viscosity of 300mpa.s was prepared using deionized water, and the slurry was uniformly passed through an iron remover. The magnetic field strength of the magnetic rods in the iron remover was 12000GS, the diameter of the magnetic rods was 35mm, the distance between the magnetic rods was 20mm, the flow rate of the slurry was 5L / min, the pipe diameter of the slurry flowing through the magnetic rods was DN50, and the gap between the pipe and the magnetic rods was 10.0mm. After the end, the polymer particle slurry 2-4# containing a triazine ring structure unit was obtained.

[0388] Melamine, benzoguanamine, formaldehyde were reacted in an alkaline environment with a pH of 8.6±0.1 to obtain a melem resin containing a triazine ring structure. The mass ratio of melamine to benzoguanamine was 99:1, and the ratio of the total number of moles of melamine and benzoguanamine to the number of moles of formaldehyde was 1:2.45. The melem resin containing a triazine ring structure was then crushed, sand milled, sieved, and removed by a magnetic ring to obtain the polymer particle slurry D2-1# containing a triazine ring structure unit.

[0389] The organic particles 2-1# to 2-4# prepared above satisfy the following characteristics: they have no melting point, no glass transition temperature Tg below 300℃, and a magnetic susceptibility of 1.5×10-7cm3 / g or less. g .

[0390] Table 2

[0391] From the above test results, it can be seen that the polymer particles containing a triazine ring structure unit prepared by the disclosed embodiment have low content of low-magnetic foreign particles, which can reduce the self-discharge of the secondary battery monomer and improve the cycle performance of the secondary battery monomer.

[0392] Next, the phenolic resin organic particles are replaced with crosslinked styrene organic particles.

[0393] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 80 mg of sodium persulfate, 20 ml of deionized water, 32 g of styrene, and 8 g of divinylbenzene. 206 g of deionized water was added to a reactor, which was heated to 65°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 hours of reaction, the temperature was increased to 86°C for 1 hour of curing reaction. The slurry with a solid content of 15% and a viscosity of 2.5 mpa.s was uniformly passed through an iron remover. The magnetic field strength of the magnetic bar in the iron remover was 12000 GS, the diameter of the magnetic bar was 35 mm, the distance between the magnetic bars was 20 mm, the slurry flow rate was 5 L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0 mm. After the reaction was completed, the crosslinked styrene-based organic particles 3-1# slurry was obtained.

[0394] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 80 mg of sodium persulfate, 20 ml of deionized water, 32 g of styrene, and 8 g of divinylbenzene. 73 g of deionized water was added to a reactor, which was heated to 65°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 hours of reaction, the temperature was increased to 86°C for 1 hour of curing reaction. The slurry with a solid content of 30% and a viscosity of 5 mpa.s was uniformly passed through an iron remover. The magnetic field strength of the magnetic bar in the iron remover was 12000 GS, the diameter of the magnetic bar was 35 mm, the distance between the magnetic bars was 20 mm, the slurry flow rate was 5 L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0 mm. After the reaction was completed, the crosslinked styrene-based organic particles 3-2# slurry was obtained.

[0395] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 80 mg of sodium persulfate, 20 ml of deionized water, 32 g of styrene, and 8 g of divinylbenzene. 206 g of deionized water was added to a reactor, which was heated to 65°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 hours of reaction, the temperature was increased to 86°C for 1 hour of curing reaction. The slurry with a solid content of 15% and a viscosity of 2.5 mpa.s was uniformly passed through an iron remover. The magnetic field strength of the magnetic bar in the iron remover was 12000 GS, the diameter of the magnetic bar was 25 mm, the distance between the magnetic bars was 20 mm, the slurry flow rate was 5 L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0 mm. After the reaction was completed, the crosslinked styrene-based organic particles 3-3# slurry was obtained.

[0396] A pre-emulsion was prepared by emulsifying 0.8 g of sodium dodecyl sulfate, 80 mg of sodium persulfate, 20 ml of deionized water, 39.5 g of styrene, and 0.5 g of divinylbenzene. 206 g of deionized water was added to a reactor, which was heated to 65°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 hours of reaction, the temperature was increased to 86°C for 1 hour of curing reaction. After the reaction was completed, the magnetic ring was removed, and cross-linked styrene-based organic particles D3-1# slurry was obtained.

[0397] The above-prepared organic particles 3-1# to 3-3# satisfy the following characteristics: no melting point, glass transition temperature T g between 106°C and 160°C.

[0398] Table 3

[0399] From the above test results, it can be seen that the cross-linked styrene-based organic particles with low magnetic foreign particle content prepared by the disclosed embodiments can reduce the self-discharge of the secondary battery cell and improve the cycle performance of the secondary battery cell.

[0400] Next, the phenolic resin-based organic particles were replaced with silicon-containing organic resin particles.

[0401] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 52 g of γ-methacryloyloxypropyl tris(trimethylsiloxy)silane, 3 g of 3-methacryloyloxypropyl triethoxysilane, and 5 g of divinylbenzene. A reactor was taken, 310 g of deionized water was added, and the temperature was increased to 68°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 hours of reaction, the temperature was increased to 75°C for 1.5 hours of curing reaction. The solid content of the reaction system was 15%, and the viscosity was 80 mpa.s. The slurry was uniformly passed through an iron remover. The magnetic field strength of the magnetic rod in the iron remover was 12000 GS, the diameter of the magnetic rod was 35 mm, the distance between the magnetic rods was 20 mm, the flow rate of the slurry was 5 L / min, the pipe diameter of the slurry flowing through the magnetic rod was DN50, and the gap between the pipe and the magnetic rod was 10.0 mm. Silicon-containing organic resin particle 4-1# slurry was obtained.

[0402] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 52 g of γ-methacryloxypropyl tris(trimethylsiloxy)silane, 3 g of 3-methacryloxypropyl triethoxysilane and 5 g of divinyl benzene. A reactor was taken, 310 g of deionized water was added, and the temperature was raised to 68°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 75°C for curing reaction for 3 h. The slurry of the reaction system had a solid content of 15% and a viscosity of 100 mpa.s, and was made to pass through an iron remover uniformly. The magnetic field strength of the magnetic bar in the iron remover was 12000 GS, the diameter of the magnetic bar was 35 mm, the distance between the magnetic bars was 20 mm, the flow rate of the slurry was 5 L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0 mm. A slurry of silicon-containing organic resin particles 4-2# was obtained.

[0403] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 52 g of γ-methacryloxypropyl tris(trimethylsiloxy)silane, 3 g of 3-methacryloxypropyl triethoxysilane and 5 g of divinyl benzene. A reactor was taken, 310 g of deionized water was added, and the temperature was raised to 68°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 75°C for curing reaction for 1.5 h. The slurry of the reaction system had a solid content of 15% and a viscosity of 80 mpa.s, and was made to pass through an iron remover uniformly. The magnetic field strength of the magnetic bar in the iron remover was 12000 GS, the diameter of the magnetic bar was 25 mm, the distance between the magnetic bars was 20 mm, the flow rate of the slurry was 5 L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0 mm. A slurry of silicon-containing organic resin particles 4-3# was obtained.

[0404] A pre-emulsion was prepared by emulsifying 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, 52 g of γ-methacryloxypropyl tris(trimethylsiloxy)silane, 3 g of 3-methacryloxypropyl triethoxysilane and 5 g of divinyl benzene. A reactor was taken, 310 g of deionized water was added, and the temperature was raised to 68°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 75°C for curing reaction for 1.5 h. The slurry of the reaction system had a solid content of 15% and a viscosity of 80 mpa.s, and was made to pass through an iron remover uniformly. The magnetic field strength of the magnetic bar in the iron remover was 12000 GS, the diameter of the magnetic bar was 25 mm, the distance between the magnetic bars was 20 mm, the flow rate of the slurry was 5 L / min, the pipe diameter of the slurry flowing through the magnetic bar was DN50, and the gap between the pipe and the magnetic bar was 10.0 mm. A slurry of silicon-containing organic resin particles 4-3# was obtained.

[0405] A pre-emulsion was prepared by mixing 0.3 g of sodium persulfate, 0.3 g of sodium bicarbonate, 1.5 g of sodium dodecyl sulfate, 30 g of deionized water, and 60 g of γ-methacryloxypropyl tris(trimethylsiloxy)silane. A reactor was charged with 310 g of deionized water, and the temperature was raised to 68°C. The pre-emulsion was added dropwise under nitrogen protection and stirring. After 4 h of reaction, the temperature was raised to 75°C for 1.5 h of curing reaction. The magnetic ring was removed, and a slurry of silicon-containing organic resin particles D4-1# was obtained.

[0406] The above-prepared organic particles 4-1# to 4-4# satisfy the following characteristics: the silicon-containing organic resin particles form a network structure with a carbon-carbon bond as the main chain, and the side chain contains a siloxane structure. The silicon-containing organic resin particles have no melting point and no glass transition temperature Tg below 300°C. g .

[0407] Table 4

[0408] As can be seen from the above test results, the silicon-containing organic resin particles prepared in the embodiments of the present disclosure have low magnetic foreign particle content, which can reduce the self-discharge of the secondary battery monomer and improve the cycle performance of the secondary battery monomer.

[0409] It should be noted that the present disclosure is not limited to the above embodiments. The above embodiments are only examples, and embodiments having the same technical idea and substantially the same function and effect within the scope of the technical solutions of the present disclosure are 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, and other ways constructed by combining part of the components of 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 layer includes organic particles satisfying that the number of magnetic foreign matter particles having a size of 25 μm to 200 μm is 0 to 30 per 1 Kg of the organic particles.

2. The secondary battery cell according to claim 1, wherein The organic particles satisfy that the number of magnetic foreign matter particles having a size of 25 μm to 200 μm is 0 to 21 per 1 Kg of the organic particles.

3. The secondary battery cell according to any one of claims 1-2, wherein, The organic particles satisfy that the number of magnetic foreign matter particles having a size of more than 200 μm is 0 per 1 Kg of the organic particles.

4. The secondary battery cell according to any one of claims 1 to 3, wherein The magnetic foreign matter particles include one or more of copper, iron, manganese, nickel, and cobalt in the form of an elemental substance, an alloy, or an oxide.

5. The secondary battery cell according to any one of claims 1 to 4, wherein The organic particles satisfy at least one of the following conditions (1) to (5): (1) The content of Cu element in the organic particles is 0 to 10 ppm; (2) The content of Fe element in the organic particles is 0 to 50 ppm; (3) The content of Mn element in the organic particles is 0 to 5 ppm; (4) The content of Ni element in the organic particles is 0 to 5 ppm; (5) The content of Co element in the organic particles is 0 to 5 ppm.

6. The secondary battery cell according to any one of claims 1 to 5, 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 820 nm.

7. The secondary battery cell according to any one of claims 1 to 6, 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.

8. The secondary battery cell according to any one of claims 1 to 7, wherein The organic particles have no melting point.

9. The secondary battery cell according to any one of claims 1 to 8, wherein The organic particles include one or more of a phenol 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.

10. The secondary battery cell according to claim 9, wherein The phenol resin-based organic particle is a thermosetting resol polymer; and / or The phenol resin-based organic particle has no glass transition temperature at 300°C or lower; and / or The volume distribution particle size Dv50 of the phenol resin-based organic particle is 200 nm to 820 nm.

11. The secondary battery cell according to any one of claims 9 to 10, wherein The polymer particle containing a triazine ring structural unit includes a bridging structure connecting the triazine ring structural units; and / or The polymer particle containing a triazine ring structural unit has no glass transition temperature at 300°C or lower; and / or The volume distribution particle size Dv50 of the polymer particle containing a triazine ring structural unit is 200 nm to 820 nm.

12. The secondary battery cell of claim 11, wherein, The bridging structure includes one or a combination of two or more of an alkylene group, an alkylene ether group, an alkylene amine group, an ester group, and an amide group.

13. The secondary battery cell of any one of claims 9-12, wherein, The polymer particle containing a triazine ring structural unit further has a substituent on the triazine ring structural unit, the substituent including one or a combination of two or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, a hydroxyl group, and a halogen.

14. The secondary battery cell of any one of claims 9-13, wherein, The polymer particles containing a triazine ring structural unit include at least one of melamine formaldehyde polymer and derivatives thereof, etherified melamine formaldehyde polymer and derivatives thereof, etherified melamine formaldehyde-polyol polymer and derivatives thereof, etherified melamine formaldehyde-polycarboxylic acid polymer and derivatives thereof, and etherified melamine formaldehyde-polyamine amide polymer and derivatives thereof.

15. The secondary battery cell according to claim 14, wherein The melamine formaldehyde polymer 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, trihydrazinyl-s-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde; and / or, The etherified melamine formaldehyde polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzotriazine formaldehyde, and butyl etherified benzotriazine formaldehyde; and / or, The etherified melamine formaldehyde-polyol polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde-ethylene glycol polymer, methyl etherified melamine formaldehyde-1,2-propanediol polymer, methyl etherified melamine formaldehyde-1,4-butanediol polymer, methyl etherified melamine formaldehyde-polyester polyol polymer, methyl etherified melamine formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine formaldehyde-ethylene glycol polymer, butyl etherified melamine formaldehyde-1,2-propanediol polymer, butyl etherified melamine formaldehyde-1,4-butanediol polymer, and butyl etherified melamine formaldehyde-polyester polyol polymer; and / or, The etherified melamine formaldehyde-polycarboxylic acid polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde-oxalic acid polymer, methyl etherified melamine formaldehyde-malic acid polymer, methyl etherified melamine formaldehyde-succinic acid polymer, methyl etherified melamine formaldehyde-citric acid polymer, methyl etherified melamine formaldehyde-terephthalic acid polymer, methyl etherified melamine formaldehyde-phthalic acid polymer, butyl etherified melamine formaldehyde-oxalic acid polymer, butyl etherified melamine formaldehyde-malic acid polymer, butyl etherified melamine formaldehyde-citric acid polymer, butyl etherified melamine formaldehyde-terephthalic acid polymer, and butyl etherified melamine formaldehyde-phthalic acid polymer; and / or, The etherified melamine formaldehyde-polyamine amide polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde-oxamide polymer, methyl etherified melamine formaldehyde-malonamide polymer, and methyl etherified melamine formaldehyde-isophthalimide polymer.

16. The secondary battery cell according to any one of claims 9 to 15, wherein the crosslinked styrene-based organic particle includes a styrene or styrene derivative structural unit and a crosslinking structural unit; and / or, The crosslinked styrenic organic particles have a glass transition temperature Tg g from 106 °C to 160 °C; and / or, the crosslinked styrene-based organic particle has a volume distribution particle size Dv50 of 85 nm to 320 nm.

17. The secondary battery cell according to claim 16, 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 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, an N,N-methylenebisacrylamide structural unit, an N,N'-vinylbisacrylamide structural unit, a 1,3,5-triacryloylhexahydro-1,3,5-triazine structural unit, and a trisallyl isocyanurate structural unit.

18. The secondary battery cell according to any one of claims 9 to 17, wherein the silicon-containing organic resin particle is a silicon-containing organic crosslinked resin particle, the silicon-containing organic resin particle containing a carbon-carbon bond and a siloxane structure; and / or, the silicon-containing organic resin particle has no glass transition temperature at 300°C or lower; and / or, the silicon-containing organic resin particle has a volume distribution particle size Dv50 of 85 nm to 320 nm.

19. The secondary battery cell of any one of claims 9-18, wherein, the silicon-containing organic resin particle is a silicon-containing organic crosslinked resin particle, the silicon-containing organic resin particle being a network structure formed with a carbon-carbon bond as a main chain, and a side chain containing a siloxane structure.

20. The secondary battery cell of any one of claims 18-19, wherein, the silicon-containing organic crosslinked resin particle includes a crosslinking structural unit; 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 diallyl maleate 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-trimethyladipoyl bis[2-ethylaziridine] structural unit, a 1,1-sebacoyl bis[2-methylaziridine] structural unit, a 1,1-(1,3-phenylenedicarbonyl) bis[2-methylaziridine] structural unit, a trimethylolpropane tris(2-methyl-1-aziridinyl propionate) structural unit, a trimethylolpropane-tris[3-(2-methylaziridinyl)propionate] structural unit, a pentaerythritol tris(3-aziridinyl)propionate structural unit.

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

22. The secondary battery cell of any one of claims 1-21, wherein, a ratio of a volume distribution particle size Dv50 of the organic particles to an average pore size of the porous base membrane is greater than or equal to 1.

1.

23. A battery device comprising a plurality of the secondary battery cell according to any one of claims 1-22.

24. An electric device comprising the secondary battery cell according to any one of claims 1-22 or the battery device according to claim 23.

25. 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 number of magnetic foreign particle having a size of 25 μm to 200 μm per 1 Kg of the organic particles is 0-30.

26. The separator film according to claim 25, 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, a volume distribution particle size Dv50 of the organic particles is less than 1 μm, and is optionally 50 nm-820 nm.

27. The separator film according to any one of claims 25-26, 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.

28. The separator membrane of any one of claims 25-27, wherein, the organic particles have no melting point.

29. The separator membrane of any one of claims 25-28, wherein, the organic particles comprise one or more of a phenol resin-based organic particle, a polymer particle containing a triazine ring structural unit, a crosslinked styrene-based organic particle, a silicon-containing organic resin particle. the organic particles have no melting point. the organic particles comprise one or more of a phenol resin-based organic particle, a polymer particle containing a triazine ring structural unit, a crosslinked styrene-based organic particle, a silicon-containing organic resin particle.

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