Silicon-containing organic resin particles, preparation method therefor, silicon-containing organic resin particles dispersion liquid,

Abstract

The invention provides a silicon-containing organic resin particle and a preparation method thereof, a silicon-containing organic resin particle dispersion liquid, an isolating membrane, a secondary battery monomer, a battery device and an electric device. The initial thermal weight loss temperature T3d of the silicon-containing organic resin particle is 290-330 DEG C. The silicon-containing organic resin particles are used in the isolating membrane, so that the secondary battery monomer has high mass energy density, high reliability and good high-temperature performance.

Description

Technical Field

[0001] This disclosure relates to a silicon-containing organic resin particle and its preparation method, a silicon-containing organic resin particle dispersion, a separator, a secondary battery cell, a battery device, and an electrical device. Background Technology

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

[0003] This disclosure provides silicon-containing organic resin particles and their preparation method, a silicon-containing organic resin particle dispersion, a separator, a secondary battery cell, a battery device, and an electrical device. The use of silicon-containing organic resin particles in the separator enables the secondary battery cell to have high energy density, high reliability, and good high-temperature performance.

[0004] In a first aspect, this disclosure provides a silicon-containing organic resin particle, wherein the initial thermogravimetric temperature T of the silicon-containing organic resin particle is... 3d The temperature ranges from 290℃ to 330℃.

[0005] Silicon-containing organic resin particles have low density, allowing secondary battery cells using them to achieve higher gravimetric energy density. The initial thermogravimetric temperature T of the silicon-containing organic resin particles... 3d The high temperature indicates that its weight does not change significantly at high temperatures, thus exhibiting high heat resistance and thermal stability during the use of secondary battery cells and during thermal abuse, and is not easily decomposed or pyrolyzed. By using silicon-containing organic resin particles in the separator, the particles can generate a force to resist the shrinkage of the separator, thereby improving the overall thermal shrinkage of the separator, enhancing its heat resistance, and improving the reliability of the secondary battery cells. Furthermore, the good stability of the silicon-containing organic resin particles in high-temperature environments also gives the secondary battery cells excellent high-temperature performance. Therefore, the use of the silicon-containing organic resin particles disclosed in this invention in the separator enables secondary battery cells to possess high energy density, high reliability, and good high-temperature performance.

[0006] In some embodiments, the initial thermogravimetric temperature T of the silicon-containing organic resin particles 3d The temperature range is 300℃-330℃.

[0007] In some embodiments, the silicon-containing organic resin particles have no melting point. The absence of a melting point in the silicon-containing organic resin particles indicates good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the porous base film, improving the heat resistance of the separator, and enhancing the reliability of the secondary battery cells.

[0008] In some embodiments, the silicon-containing organic resin particles have no glass transition temperature below 300°C. The fact that the silicon-containing organic resin particles have no glass transition temperature below 300°C indicates good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the porous base film, improving the heat resistance of the separator, and enhancing the reliability of the secondary battery cells.

[0009] In some embodiments, the dissolution rate of the silicon-containing organic resin particles after being immersed at 60°C for 7 days in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 is less than or equal to 3%. The low dissolution rate of the silicon-containing organic resin particles in organic solvents results in higher structural stability during long-term use of the secondary battery cell and higher chemical stability in the electrolyte, thereby enabling the secondary battery cell to have longer cycle stability.

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

[0011] In some embodiments, the cyclic voltammetry curve of the silicon-containing organic resin particles in the first cycle does not exhibit an oxidation peak within a voltage range of 2.50V to 4.45V. The absence of an oxidation peak in the cyclic voltammetry curve of the silicon-containing organic resin particles in the first cycle within this voltage range indicates that the silicon-containing organic resin particles are stable within this voltage range. Therefore, the silicon-containing organic resin particles of this disclosure possess good electrochemical stability and can be applied to high-voltage secondary battery cells to improve the operating voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to exhibit good capacity performance characteristics under high voltage.

[0012] In some embodiments, the true density of the silicon-containing organic resin particles is 1.1 g / cm³. 3 -1.4g / cm 3 .

[0013] In some embodiments, the silicon-containing organic resin particles comprise aggregates of primary particles. The inclusion of aggregates of primary particles increases the overall size of the silicon-containing organic resin particles. When used in a separator, this effectively reduces the probability of small particles clogging pores and allows the porous coating of the separator to form more pores, thereby improving the electrolyte absorption and wettability of the separator, and ultimately enabling the secondary battery cells to have good cycle performance.

[0014] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles is 300 nm-800 nm. A volume distribution particle size Dv50 within this range is beneficial for the separator to have good heat resistance and air permeability.

[0015] In some embodiments, the primary particles in the aggregate have a particle size of 30 nm to 250 nm.

[0016] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, which contain carbon-carbon bonds and silicon-oxygen structures.

[0017] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, wherein the silicon-containing organic resin particles are a network structure formed with carbon-carbon bonds as the main chain and the side chains contain silicon-oxygen structures.

[0018] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, and the silicon-containing organic cross-linked resin particles include cross-linked structural units.

[0019] Optionally, the crosslinked structural units include divinylbenzene structural units, diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, and di... The structural unit comprises one or more of the following: tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0020] Secondly, this disclosure provides a method for preparing silicon-containing organic resin particles, comprising the following steps: providing a pre-emulsion containing monomers, crosslinking agents, emulsifiers, initiators, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions; wherein the monomers include silane coupling agents containing alkenyl groups and / or acryloyloxy groups; drying the product obtained from the emulsion polymerization reaction; baking it under an inert gas atmosphere; and then subjecting it to a crushing and grinding process to obtain silicon-containing organic resin particles.

[0021] In some embodiments, the product obtained from the emulsion polymerization reaction is dried at a temperature of 80°C-150°C.

[0022] In some embodiments, the product obtained from the emulsion polymerization reaction is dried for 2-12 hours.

[0023] In some embodiments, the product obtained from the emulsion polymerization reaction is dried by vacuum drying, spray drying, forced air drying, microwave drying, or fluidized bed drying.

[0024] In some embodiments, the baking temperature is 160°C-250°C.

[0025] In some embodiments, the baking process is carried out at a temperature of 1 hour to 8 hours.

[0026] In some embodiments, the grinding process includes the following steps: mixing the crushed material with a solvent, grinding media and optional dispersant to obtain a mixed slurry, and then grinding the mixed slurry to obtain silicon-containing organic resin particles.

[0027] Optionally, the solvent includes one or more of water, methanol, and ethanol.

[0028] Optionally, the dispersant includes one or more of polyacrylic acid dispersants, carboxymethyl cellulose dispersants, polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone.

[0029] Optionally, the grinding media includes one or more of zirconia balls, alumina balls, and silicon nitride balls.

[0030] Optionally, the average particle size of the grinding media is 0.1 mm to 2 mm.

[0031] Optionally, the filling rate of the abrasive media is 30%-80%.

[0032] Optionally, the grinding speed is 500rpm-3000rpm.

[0033] In some embodiments, the heating temperature during the ripening stage of the emulsion polymerization reaction is 70°C-95°C.

[0034] In some embodiments, the heating time for the ripening stage of the emulsion polymerization reaction is 1-5 hours.

[0035] In some embodiments, the inert gas includes one or more of nitrogen, argon, and helium.

[0036] In some embodiments, the emulsion polymerization reaction includes the following steps: under a first temperature, inert gas protection and stirring conditions, the pre-emulsion is dropwise added to a reactor containing water, and after a first reaction time, the temperature is raised to the heating temperature of the maturation stage to carry out the maturation reaction, thereby obtaining silicon-containing organic resin particles.

[0037] In some embodiments, the first temperature is 55°C-70°C.

[0038] In some embodiments, the first time is 3h-6h.

[0039] In some embodiments, the monomer includes γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-tert-butoxyvinylsilane, ethylene One or more of the following: tri(β-methoxyethoxy)silane, ethylenetri[(1-methylvinyl)oxy]silane, vinyltritert-butylperoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane.

[0040] In some embodiments, the crosslinking agent includes 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 di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0041] In some embodiments, the mass fraction of the crosslinking agent is 1.5%-18% based on the total mass of the monomer and the crosslinking agent being 100%.

[0042] Thirdly, this disclosure provides a silicon-containing organic resin particle dispersion, which includes silicon-containing organic resin particles and a dispersant as described in the first aspect, or is obtained by the method described in the second aspect.

[0043] Fourthly, this disclosure provides a separating membrane comprising a porous base membrane and a porous coating located on at least one side of the porous base membrane, the porous coating comprising silicon-containing organic resin particles of the first aspect, or silicon-containing organic resin particles prepared by the method of the second aspect.

[0044] In some embodiments, the mass content of the silicon-containing organic resin particles in the porous coating is 50%-99% based on the total mass of the porous coating.

[0045] In some embodiments, the thickness of the porous coating is 0.5 μm-5 μm.

[0046] In some embodiments, the separation film is heated at a constant temperature of 130°C for 1 hour, and the longitudinal thermal shrinkage rate is less than or equal to 1.5%.

[0047] In some embodiments, the separator is heated at a constant temperature of 130°C for 1 hour, and the transverse thermal shrinkage rate is less than or equal to 1.5%.

[0048] Fifthly, this disclosure provides a secondary battery cell, which includes a positive electrode, a negative electrode, and a separator as described in the fourth aspect of this disclosure, wherein the separator is disposed between the positive electrode and the negative electrode.

[0049] In a sixth aspect, this disclosure provides a battery device comprising a plurality of secondary battery cells according to the fifth aspect of this disclosure.

[0050] In a seventh aspect, this disclosure provides an electrical device that includes a secondary battery cell according to the fifth aspect of this disclosure or a battery device according to the sixth aspect. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0052] Figure 1 A schematic diagram of a secondary battery cell provided in some embodiments of this disclosure is shown.

[0053] Figure 2 A schematic diagram of an electrical device provided in some embodiments of this disclosure is shown. Detailed Implementation

[0054] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the silicon-containing organic resin particles, their preparation methods, dispersions, separators, secondary battery cells, battery devices, and electrical devices of this disclosure. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for a full understanding of this disclosure by those skilled in the art and are not intended to limit the subject matter of the claims.

[0055] The "range" disclosed in this disclosure is defined by a lower limit and an upper limit, whereby a given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and if maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

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

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

[0058] Unless otherwise specified, all steps in this disclosure may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0059] Unless otherwise specified, in this disclosure, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0060] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0061] In the description of the embodiments of this disclosure, unless otherwise specified, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0062] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0063] The secondary battery cell mentioned in the embodiments of this disclosure can independently perform charge and discharge functions. After discharge, it can be reactivated by charging to allow for continued use. The secondary battery cell can be cylindrical, cuboid, or other shapes, and the embodiments of this disclosure are not limited in this regard. Figure 1 The example is a cuboid-structured secondary battery cell 5.

[0064] The secondary battery cells provided in the embodiments of this disclosure may include, but are not limited to, lithium battery cells and sodium battery cells, such as lithium-ion battery cells, sodium-ion battery cells, lithium metal battery cells, sodium metal battery cells, etc.

[0065] The secondary battery cell provided in the embodiments of this disclosure includes an electrode assembly. The electrode assembly can be a wound structure or a stacked structure, and the embodiments of this disclosure are not limited in this regard. The secondary battery cell also includes an outer packaging, which can be used to encapsulate the electrode assembly. The outer packaging can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging can also be a soft package, such as a pouch-type soft package. The material of the soft package can be plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0066] The battery apparatus mentioned in the embodiments of this disclosure may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple secondary battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0067] In some embodiments, a battery cell assembly is typically formed by arranging multiple secondary battery cells.

[0068] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple secondary battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple secondary battery cells together with cable ties.

[0069] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0070] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0071] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple secondary battery cells to the housing.

[0072] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0073] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0074] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

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

[0076] Figure 2 This is a schematic diagram of an example electrical device. The device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0077] In the context of this disclosure, the "silicone-containing organic resin particles" primarily serve to improve heat resistance in the porous coating of the separator, and have virtually no adhesive effect.

[0078] The separator is a crucial component supporting the charge-discharge electrochemical process of a secondary battery cell. Commonly used separators are made of polyolefin materials; however, polyolefins have poor heat resistance and are prone to softening or melting at high temperatures, which can lead to short circuits in the secondary battery cells. To improve the heat resistance of the separator, a porous coating is usually applied. Boehmite, alumina, and other inorganic particles are commonly used heat-resistant fillers; however, these fillers have high density and large mass for the same bulk volume, thus affecting the energy density of the secondary battery cells.

[0079] Based on this, the present disclosure provides a silicon-containing organic resin particle, which, when used in a separator, enables secondary battery cells to possess high energy density, high reliability, and good high-temperature performance.

[0080] The initial thermogravimetric temperature T of the silicon-containing organic resin particles disclosed herein 3d The temperature ranges from 290℃ to 330℃.

[0081] Silicon-containing organic resin particles have low density, allowing secondary battery cells using them to achieve higher gravimetric energy density. The initial thermogravimetric temperature T of the silicon-containing organic resin particles... 3d The high temperature indicates that its weight does not change significantly at high temperatures, thus exhibiting high heat resistance and thermal stability during the use of secondary battery cells and during thermal abuse, and is not easily decomposed or pyrolyzed. By using silicon-containing organic resin particles in the separator, the particles can generate a force that resists the shrinkage of the separator, thereby improving the overall thermal shrinkage of the separator, enhancing its heat resistance, and improving the reliability of the secondary battery cells. Furthermore, the good stability of the silicon-containing organic resin particles in high-temperature environments also gives the secondary battery cells excellent high-temperature performance.

[0082] Therefore, the silicon-containing organic resin particles disclosed herein, when used in a separator, enable secondary battery cells to possess high energy density, high reliability, and good high-temperature performance.

[0083] Optionally, the initial thermogravimetric temperature T of the silicone resin particles 3d It can be 300℃-330℃.

[0084] Initial thermogravimetric temperature T 3d This refers to the temperature at which the sample mass loses 3% of its initial mass in a thermogravimetric analysis test. The initial thermogravimetric temperature T for silicon-containing organic resin particles. 3dThe test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the alumina crucible of the thermogravimetric analyzer (TGA), level it, and cover the crucible with the lid; Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; Temperature rise program: heating rate 10℃ / min, temperature range 35℃-600℃; Obtain the temperature corresponding to a 3% loss of sample mass relative to the initial mass (i.e., 97% of the initial mass) from the test curve, which is the initial thermogravimetric temperature T. 3d .

[0085] In some embodiments, the true density of the silicone-containing organic resin particles can be 1.1 g / cm³. 3 -1.4g / cm 3 .

[0086] Currently, the true density of inorganic particles such as boehmite and alumina is typically 2.5 g / cm³. 3 -3.5g / cm 3 The silicon-containing organic resin particles disclosed herein have a low true density, thereby enabling secondary battery cells using the separator of this disclosure to have a higher mass energy density.

[0087] The silicon-containing organic resin particles disclosed herein are poorly soluble in both water and organic solvents, such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), and chloroform, at 25°C. They are also insoluble in the mobile phase used in gel permeation chromatography and the molecular weight of the silicon-containing organic resin particles cannot be determined by gel permeation chromatography.

[0088] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, which contain carbon-carbon bonds and silicon-oxygen structures.

[0089] Optionally, the silicon-containing organic resin particles have a network structure with carbon-carbon bonds as the main chain and silicon-oxygen structures in the side chains.

[0090] Optionally, the silicon-containing organic resin particles have a network structure with carbon-carbon bonds as the main chain and side chains containing silicon-oxygen structures and benzene ring structures.

[0091] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, and the silicon-containing organic cross-linked resin particles include cross-linked structural units.

[0092] In some embodiments, the crosslinking structural unit may include a divinylbenzene structural unit, a diethylene glycol divinyl ether structural unit, a triethylene glycol divinyl ether structural unit, a diallyl maleate structural unit, an ethylene glycol dimethacrylate structural unit, a 1,4-butanediol diacrylate structural unit, a 1,6-hexanediol diacrylate structural unit, a 1,8-octanediol diacrylate structural unit, a trimethylolpropane triacrylate structural unit, a pentaerythritol trimethacrylate structural unit, and a tetraethylene glycol dimethacrylate structural unit. One or more of the following structural units: tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tri(2-methyl-1-aziridinium propionate), trimethylolpropane tri[3-(2-methylaziridinium)propionate], and pentaerythritol tri(3-aziridinium)propionate.

[0093] Optionally, the crosslinking structural unit may include a divinylbenzene structural unit.

[0094] Optionally, the crosslinking structural unit may include a divinylbenzene structural unit, as well as diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, and di... The structural unit comprises one or more of the following: tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0095] In some embodiments, the silicone-containing organic resin particles have no melting point.

[0096] The silicon-containing organic resin particles disclosed herein have no melting point, indicating that they have good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0097] Melting point can be tested as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of a differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The DSC curve is used to determine whether the silicon-containing organic resin particles have a melting point below 300℃. Silicon-containing organic resin particles having no melting point means that the DSC curve of the silicon-containing organic resin particles does not show a melting peak.

[0098] In some embodiments, the silicone-containing organic resin particles have no glass transition temperature below 300°C.

[0099] Silicon-containing organic resin particles have no glass transition temperature below 300℃, indicating good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0100] Glass transition temperature T g The test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The glass transition temperature T of the silicon-containing organic resin particles can be determined by the DSC curve. g .

[0101] Glass transition temperature T g It refers to the transition temperature from the glassy state to the elastic state, which shows a step-like change on the DSC curve.

[0102] Silicon-containing organic resin particles have no glass transition temperature T below 300℃ g This means that the DSC curve of the silicon-containing organic resin particles does not show a step-like change in the range below 300℃.

[0103] In some embodiments, the dissolution rate of silicone-containing organic resin particles soaked in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days can be less than or equal to 3%.

[0104] Silicon-containing organic resin particles have a low dissolution rate in organic solvents, high structural stability during long-term use of secondary battery cells, and high chemical stability in electrolytes, which can enable secondary battery cells to have longer cycle stability.

[0105] The dissolution rate of silicon-containing organic resin particles can be tested as follows: Take an appropriate amount of sample (e.g., about 1g), and record its mass as m1. Place it in a semi-permeable membrane sample bag, seal it, and record the total mass of the sample bag as m2. The sample bag is permeable to the solvent but not to the sample. Immerse the sample bag in an appropriate amount of solvent (e.g., about 50g) at 60℃ for 7 days. After that, remove the sample bag, drain it, dry it, and weigh the total mass of the sample bag again as m3. Dissolution rate = (m2-m3) / m1×100%. The solvent is a mixed solvent obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7.

[0106] In some embodiments, the swelling degree of silicone-containing organic resin particles soaked in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days can be less than or equal to 3%.

[0107] Silicon-containing organic resin particles have low swelling in organic solvents and high structural stability during long-term use of secondary battery cells, thereby improving the problem of decreased air permeability of the separator during use.

[0108] The swelling degree of silicon-containing organic resin particles can be tested as follows: Take an appropriate amount of sample (e.g., about 1g), denoted as m1, and place it in a semi-permeable membrane sample bag. Seal the bag; the sample bag should be permeable to the solvent but not to the sample. Immerse the sample bag in an appropriate amount of solvent (e.g., about 50g) at 60°C for 7 days. After immersion, remove the sample bag and then remove the sample from the bag. Wipe away excess solvent and weigh the sample again, m2. Swelling degree = (m2-m1) / m1×100%. The solvent is a mixed solvent obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 3:7.

[0109] In some embodiments, the cyclic voltammetry curve of the silicon-containing organic resin particles during the first cycle does not exhibit an oxidation peak in the voltage range of 2.50V to 4.45V.

[0110] The cyclic voltammetry curve of the silicon-containing organic resin particles in the first cycle shows no oxidation peak in the voltage range of 2.50V to 4.45V, indicating that the silicon-containing organic resin particles are stable in this voltage range. Therefore, the silicon-containing organic resin particles disclosed herein exhibit good electrochemical stability and can be applied to high-voltage secondary battery cells to improve the operating voltage and energy density of the secondary battery cells, and also enable the secondary battery cells to have good capacity performance characteristics under high voltage.

[0111] The oxidation peak potential of the cyclic voltammetry curve of silicon-containing organic resin particles can be tested as follows: Silicon-containing organic resin particles, binder polyacrylate, and conductive agent conductive carbon black are dissolved in water at a solid content mass ratio of 64:7:29 to prepare a slurry. The slurry is coated onto aluminum foil as the positive electrode, and lithium foil is used as the negative electrode to assemble a coin cell. Cyclic voltammetry (CV) is performed on the coin cell at a scan rate of 0.10 mV / s, a voltage range of 2.50 V–5.00 V, and 3 cycles. The voltage corresponding to the peak point of the first cyclic voltammetry curve is taken as the oxidation peak potential. The electrolyte used in the test is LiPF6 with a concentration of 1 mol / L. The solvent of the electrolyte is obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) at a volume ratio of 3:7.

[0112] In some embodiments, the silicone-containing organic resin particles comprise aggregates of primary particles.

[0113] Typically, aggregates of primary particles can also be referred to as secondary particles.

[0114] Silicon-containing organic resin particles include aggregates of primary particles, thereby increasing the overall size of the silicon-containing organic resin particles. When used in separators, they can effectively reduce the probability of small particles clogging pores and also enable the porous coating of the separator to form more pores. This can improve the electrolyte absorption and wettability of the separator, and thus enable the secondary battery cells to have good cycle performance.

[0115] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles can be 300nm-800nm, for example, it can be 300nm, 320nm, 360nm, 400nm, 440nm, 480nm, 520nm, 560nm, 600nm, 640nm, 680nm, 720nm, 760nm, 780nm, or any range of the above values.

[0116] The volume distribution particle size Dv50 of the silicone organic resin particles is within the above range, which is beneficial for the separator to have good heat resistance and air permeability.

[0117] Optionally, the volume distribution particle size Dv50 of the silicon-containing organic resin particles can be 320nm-800nm, 360nm-800nm, 400nm-800nm, 320nm-760nm, 360nm-760nm, 400nm-760nm, 320nm-720nm, 360nm-720nm, or 400nm-720nm.

[0118] Dv50 represents the particle size corresponding to a cumulative volumetric distribution percentage of 50% for the material. It can be measured using a laser particle size analyzer, referring to GB / T19077-2016. During testing, add 1g of the sample to a clean small beaker, along with 20ml of deionized water. Sonicate at 53kHz / 120W for 5 minutes to ensure complete dispersion. Turn on the laser particle size analyzer, clean the optical path system, and automatically test the background. Stir the sonicated solution to ensure uniform dispersion, then place it in the sample cell as required and begin measuring the particle size. A MasterSizer 3000 laser particle size analyzer can be used as the testing instrument.

[0119] In some embodiments, the particle size of the primary particles in the agglomerate can be 30nm-250nm. Optionally, the particle size of the primary particles in the agglomerate can be 30nm-240nm, 30nm-220nm, 30nm-200nm, 30nm-180nm, 30nm-160nm, 30nm-150nm, 50nm-240nm, 50nm-220nm, 50nm-200nm, 50nm-180nm, 50nm-160nm, 50nm-150nm, 80nm-240nm, 80nm-220nm, 8 0nm-200nm, 80nm-180nm, 80nm-160nm, 80nm-150nm, 85nm-240nm, 85nm-220nm, 85nm-200nm, 85nm-180nm, 85nm-160nm, 85nm-150nm, 90nm-240nm, 90nm-220nm, 90nm-200nm, 90nm-180nm, 90nm-160nm, 90nm-150nm.

[0120] The particle size of primary particles can be tested using the following method: Silicone-containing organic resin particles are laid and adhered to conductive adhesive to form a sample measuring 6 cm × 1.1 cm. The particle morphology is then tested using a scanning electron microscope (e.g., ZEISS Sigma 300), with reference to JY / T010-1996. The particle size of the primary particles is measured from the resulting scanning electron microscope image.

[0121] This disclosure also provides a method for preparing silicon-containing organic resin particles, which can prepare the above-mentioned silicon-containing organic resin particles.

[0122] The preparation method of silicon-containing organic resin particles includes the following steps: providing a pre-emulsion containing monomers, crosslinking agents, emulsifiers, initiators, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions; the monomers include silane coupling agents containing alkenyl groups and / or acryloyloxy groups; drying the product obtained from the emulsion polymerization reaction; baking it under an inert gas atmosphere; and then subjecting it to crushing and grinding processes to obtain silicon-containing organic resin particles.

[0123] The monomers include silane coupling agents containing alkenyl and / or acryloyloxy groups, thus initiating free radical generation and cross-linking reactions between monomers, and the monomers also undergo cross-linking reactions with the cross-linking agents. Therefore, using the monomers and cross-linking agents of this disclosure as raw materials, silicon-containing organic resin particles with a three-dimensional network molecular structure can be formed. These silicon-containing organic resin particles are not easily softened or deformed at high temperatures and have high heat resistance.

[0124] The initial thermogravimetric temperature T can be obtained by drying the product obtained from the emulsion polymerization reaction and then baking it under an inert gas atmosphere. 3d High-density silicon-containing organic resin particles with morphology including aggregates of primary particles.

[0125] In some embodiments, the drying methods for the products obtained from emulsion polymerization may include, but are not limited to, vacuum drying, spray drying, forced air drying, microwave drying, or fluidized bed drying.

[0126] In some embodiments, the drying temperature of the product obtained from the emulsion polymerization reaction can be 80℃-150℃, for example, it can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, or any combination of the above values.

[0127] In some embodiments, the drying time of the product obtained from the emulsion polymerization reaction can be 2h-12h, for example, it can be 2h, 2.4h, 2.8h, 3.2h, 3.6h, 4h, 4.4h, 4.8h, 5.2h, 5.6h, 6h, 6.4h, 6.8h, 7.2h, 7.6h, 8h, 8.4h, 8.8h, 9.2h, 9.6h, 10h, 10.4h, 10.8h, 11.2h, 11.6h, 12h, or any range of the above values.

[0128] Baking is carried out in an inert gas atmosphere. In some embodiments, the inert gas may include one or more of nitrogen, argon, and helium.

[0129] In some embodiments, the baking temperature can be 160℃-250℃, for example, it can be 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, or any range of the above values.

[0130] In some embodiments, the baking time can be 1 hour to 8 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.4 hours, 3.6 hours, 3.8 hours, 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours, 6 hours, 6.2 hours, 6.4 hours, 6.6 hours, 6.8 hours, 7 hours, 7.2 hours, 7.4 hours, 7.6 hours, 7.8 hours, 8 hours, or any range of the above values. Optionally, the baking time can be 2 hours to 8 hours, 2.4 hours to 8 hours, or 3 hours to 8 hours.

[0131] In some embodiments, the crushing process can employ air jet mills, vibratory mills, mechanical mills, ultrasonic mills, ball mills, etc.

[0132] In some embodiments, the grinding process may include the following steps: mixing crushed material with solvent, grinding media and optional dispersant to obtain a mixed slurry, and then grinding the mixed slurry to obtain silicon-containing organic resin particles.

[0133] Optionally, the solvent may include one or more of water, methanol, and ethanol. More preferably, the solvent may include water.

[0134] Optionally, the dispersant may include one or more of polyacrylic acid dispersants, carboxymethyl cellulose dispersants, polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone. Optionally, the polyacrylic acid dispersant may include one or more of polypropionic acid, sodium polyacrylate, potassium polyacrylate, and ammonium acrylate. Optionally, the carboxymethyl cellulose dispersant may include one or more of carboxymethyl cellulose, sodium carboxymethyl cellulose, and potassium carboxymethyl cellulose.

[0135] Optionally, the polishing media may include one or more of zirconia balls, alumina balls, and silicon nitride balls.

[0136] Optionally, the average particle size of the grinding media can be 0.1 mm to 2 mm.

[0137] Optionally, the filling rate of the grinding media can be 30%-80%. This allows the grinding media to fully contact the silicon-containing organic resin particles, improving the grinding effect.

[0138] Optionally, the grinding speed can be 500rpm-3000rpm, for example, 500rpm, 600rpm, 700rpm, 800rpm, 900rpm, 1000rpm, 1100rpm, 1200rpm, 1300rpm, 1400rpm, 1500rpm, 1600rpm, 1700rpm, 1800rpm, 1900rpm, 2000rpm, 2100rpm, 2200rpm, 2300rpm, 2400rpm, 2500rpm, 2600rpm, 2700rpm, 2800rpm, 2900rpm, 3000rpm, or any range of the above values.

[0139] In some embodiments, the heating temperature during the ripening stage of the emulsion polymerization reaction can be 70℃-95℃, for example, it can be 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, or any range of the above values. Optionally, the heating temperature during the ripening stage of the emulsion polymerization reaction can be 72℃-95℃, 75℃-95℃, 78℃-95℃, 72℃-92℃, 75℃-92℃, or 78℃-92℃.

[0140] In some embodiments, the heating time for the ripening stage of the emulsion polymerization reaction can be 1h-5h, for example, it can be 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or any range of the above values.

[0141] The emulsion polymerization reaction is carried out under the protection of an inert gas. In some embodiments, the inert gas may include one or more of nitrogen, argon, and helium.

[0142] In some embodiments, the emulsion polymerization reaction may include the following steps: under a first temperature, inert gas protection and stirring conditions, a pre-emulsion is dropwise added to a reactor containing water, and after a first reaction time, the temperature is raised to the heating temperature of the maturation stage to carry out the maturation reaction, thereby obtaining silicon-containing organic resin particles.

[0143] In some embodiments, the first temperature can be 55°C-70°C.

[0144] In some embodiments, the first time can be 3h-6h.

[0145] In some embodiments, the crosslinking agent may be a multifunctional crosslinking agent.

[0146] Optionally, the crosslinking agent may include one or more of the following: divinylbenzene, diethylene glycol divinyl ether, triethylene glycol divinyl ether, diallyl maleate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-nonaiyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0147] Optionally, the crosslinking agent may include divinylbenzene.

[0148] Optionally, the crosslinking agent may include divinylbenzene and one or more of diethylene glycol divinyl ether, triethylene glycol divinyl ether, diallyl maleate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-nonaiyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0149] In some embodiments, the monomer may include a vinylsilane coupling agent and / or an acryloyloxysilane coupling agent.

[0150] Optionally, the monomer may include γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-tert-butoxyvinylsilane, vinyltri... One or more of the following: (β-methoxyethoxy)silane, ethylenetri[(1-methylvinyl)oxy]silane, vinyltritert-butylperoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloyloxy)propylmethyldiethoxysilane.

[0151] In some embodiments, the mass fraction of the crosslinking agent, based on the total mass of monomers and crosslinking agents (100%), can be 1.5%-18%, for example, 1.5%, 3%, 4%, 5%, 6%, 7%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 16%, 17%, 18%, or any combination of the above values. When the mass fraction of the crosslinking agent is within the above range, silicone-containing organic resin particles with good heat resistance can be obtained.

[0152] Optionally, the mass fraction of the crosslinking agent can be 4%-18%, 6%-18%, 8%-18%, 4%-16%, 6%-16%, 8%-16%, 4%-15%, 6%-15%, or 8%-15%.

[0153] In some embodiments, the emulsifier may include, but is not limited to, one or more of alkyl sulfates, alkyl sulfonates, Tween emulsifiers, fatty alcohol polyoxyethylene ethers, fatty alcohol polyoxypropylene ethers, cetearyl alcohol polyethers, and oleyl alcohol polyethers. Optionally, the emulsifier includes one or more of sodium lauryl sulfate, sodium lauryl sulfonate, Tween 20, Tween 40, lauryl ether-7, lauryl ether-9, lauryl ether-10, and oleyl alcohol polyether-10.

[0154] In some embodiments, the initiator may be one or more of sodium persulfate, potassium persulfate, ammonium persulfate, sodium sulfite, sodium bisulfite, azobisisobutyronitrile, azobisisobutyramidine hydrochloride, azobisisobutyramidine imidazoline hydrochloride, and azobisisopropylimidazoline.

[0155] In some embodiments, the mass fraction of the initiator can be 0.15%-2.5% based on the total mass of monomers and crosslinking agents as 100%, for example, it can be 0.15%, 0.2%, 0.3%, 0.4%, 0.5%, 0.7%, 0.9%, 1.1%, 1.3%, 1.5%, 1.7%, 1.9%, 2.1%, 2.3%, 2.5%, or any range of the above values.

[0156] Optionally, the mass fraction of the initiator can be 0.3%-2.1%, 0.3%-1.9%, 0.3%-1.7%, 0.3%-1.5%, or 0.3%-1.3%.

[0157] In some embodiments, the preemulsion may further include a pH adjuster. Optionally, the pH adjuster may include, but is not limited to, one or more of sodium bicarbonate, sodium hydroxide, ammonia, etc.

[0158] This disclosure also provides a silicon-containing organic resin particle dispersion, which includes the above-mentioned silicon-containing organic resin particles and a dispersant, or is obtained by the preparation method of the silicon-containing organic resin particles of this disclosure.

[0159] This disclosure also provides an isolation membrane.

[0160] The separator includes a porous base membrane and a porous coating located on at least one side of the porous base membrane. The porous coating includes an adhesive and silicon-containing organic resin particles of the present disclosure or silicon-containing organic resin particles prepared by the method of the present disclosure.

[0161] Both the porous base membrane and the porous coating have a porous structure, which gives the separator good air permeability and facilitates ion passage. In the porous coating, the silicon-containing organic resin particles are interconnected and fixed by a binder, and the gaps between the silicon-containing organic resin particles can form a porous structure.

[0162] In some embodiments, the mass content of silicon-containing organic resin particles in the porous coating may be 50%-99% based on the total mass of the porous coating.

[0163] Optionally, the mass content of the silicon-containing organic resin particles in the porous coating can be 60%-99%, 70%-99%, 80%-99%, 85%-99%, 88%-99%, 80%-97%, 85%-97%, 88%-97%, 80%-95%, 85%-95%, or 88%-95%.

[0164] In some embodiments, the binder in the porous coating may be one or more of the following: polyacrylate binders, nitrile rubber binders, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0165] In some embodiments, the porous coating may further include a dispersant, such as, but not limited to, polyacrylic acid dispersants or carboxymethyl cellulose dispersants. As an example, the dispersant may include, but is not limited to, one or more of sodium carboxymethyl cellulose, sodium polyacrylate, and ammonium polyacrylate.

[0166] In some embodiments, the separator may also include polymer binder particles.

[0167] The "polymer binder particles" in the porous coating of the separator membrane play a role in improving the adhesion between the separator membrane and the electrode, but they have virtually no heat resistance.

[0168] In some embodiments, polymer binder particles may be embedded in silicone-containing organic resin particles and form protrusions on the porous coating surface.

[0169] In other embodiments, the porous coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on the porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the heat-resistant layer on the side away from the porous base membrane. Silicone organic resin particles are disposed in the heat-resistant layer, and polymer adhesive particles are disposed in the adhesive layer.

[0170] In some other embodiments, the porous coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on one side of the porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the other side of the porous base membrane. Silicone organic resin particles are disposed in the heat-resistant layer, and polymer adhesive particles are disposed in the adhesive layer.

[0171] In some embodiments, the average particle size of the polymer binder particles can be 6 μm-18 μm.

[0172] In some embodiments, the polymer binder particles may include vinylidene fluoride polymer particles, such as polyvinylidene fluoride (PVDF) particles and / or copolymer particles of vinylidene fluoride monomer and comonomer.

[0173] Comonomers may include at least one of olefin monomers, fluorinated olefin monomers, chlorinated olefin monomers, acrylate monomers, acrylic monomers, and fluoroether monomers.

[0174] Optionally, the comonomer may include at least one of the following: trifluoroethylene, trifluorochloroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl) ether (e.g., perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether), perfluoro(1,3-m-dioxacyclopentene), and perfluoro(2,2-dimethyl-1,3-m-dioxacyclopentene).

[0175] In some embodiments, the thickness of the porous coating can be 0.5 μm-5 μm. The thickness of the porous coating refers to the thickness of the porous coating located on one side of the porous base film. Optionally, the thickness of the porous coating can be 0.5 μm-4 μm, 0.5 μm-3 μm, 0.5 μm-2 μm, 0.6 μm-4 μm, 0.6 μm-3 μm, 0.6 μm-2 μm, 0.8 μm-4 μm, 0.8 μm-3 μm, or 0.8 μm-2 μm.

[0176] In some embodiments, the porous base membrane may comprise a membrane or nonwoven web selected from any one or at least two of the following: polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymer, polyphenylene sulfide, and polyvinylnaphthalene.

[0177] Porous base membranes can be single-layer thin films or multi-layer composite thin films. When a porous base membrane is a multi-layer composite thin film, the materials of each layer can be the same or different.

[0178] In some embodiments, the thickness of the porous base film can be 4μm-12μm, and optionally 4μm-9μm.

[0179] In some embodiments, the porosity of the porous base membrane can be 25%-60%, optionally 28%-50%.

[0180] In some embodiments, the thickness of the separator can be 5μm-14μm, optionally 5μm-12μm or 6μm-12μm. This is beneficial for improving the energy density of the secondary battery cell.

[0181] In some embodiments, the longitudinal (MD) thermal shrinkage rate of the separator film can be less than or equal to 1.5% after being heated at a constant temperature of 130°C for 1 hour.

[0182] In some embodiments, the transverse (TD) heat shrinkage rate of the separator film can be less than or equal to 1.5% after being heated at a constant temperature of 130°C for 1 hour.

[0183] It should be noted that the porous coating parameters of the above-mentioned separator are all the porous coating parameters of one side of the porous base membrane. When the porous coating is disposed on both sides of the porous base membrane, if the porous coating parameters of either side meet the requirements of this disclosure, it is considered to fall within the protection scope of this disclosure.

[0184] The separator membrane can be prepared according to methods known in the art.

[0185] In some embodiments, a slurry comprising silicone organic resin particles and a binder can be coated on at least one side of a porous base membrane, and after drying, a separation membrane is obtained.

[0186] In some embodiments, the slurry may further include polymer binder particles, which, after drying, are embedded in silicone-containing organic resin particles and form protrusions on the porous coating surface.

[0187] In some embodiments, the method for preparing the separator membrane may include: coating a heat-resistant layer slurry comprising silicone organic resin particles and a binder onto at least one side of a porous base membrane, and drying it to form a heat-resistant layer; and coating an adhesive layer slurry comprising polymer binder particles and a binder onto at least a portion of the surface of the heat-resistant layer, and drying it to obtain the separator membrane.

[0188] In some embodiments, the method for preparing the separator membrane may include: coating a heat-resistant slurry comprising silicone organic resin particles and a binder onto one side of a porous base membrane, and coating an adhesive layer slurry comprising polymer binder particles and a binder onto at least a portion of the surface of the other side of the porous base membrane, and drying the slurry to obtain the separator membrane.

[0189] In some embodiments, the solvent for the slurry may be water, such as deionized water.

[0190] In some embodiments, the slurry may also include other components, such as dispersants and / or wetting agents.

[0191] This disclosure also provides a secondary battery cell. The secondary battery cell includes the separator provided in this disclosure.

[0192] A secondary battery cell also includes a positive electrode, a negative electrode, and an electrolyte, with a separator disposed between the positive and negative electrodes. The positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process.

[0193] The secondary battery cells disclosed herein may include, but are not limited to, lithium battery cells, sodium battery cells, etc. The composition of the positive electrode, negative electrode and electrolyte may differ depending on the type of secondary battery cell.

[0194] [Positive electrode plate]

[0195] In some embodiments, the positive electrode may include a positive current collector and a positive electrode film layer disposed on at least one surface of the positive current collector and comprising a positive electrode active material. For example, the positive current collector has two surfaces opposite each other in its thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive current collector.

[0196] Taking a lithium-ion battery cell as an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites, and their respective modified compounds. In some embodiments, to further improve the energy density of the secondary battery cell, the positive electrode active material may include materials with the general formula Li a Ni b Co c M d O e A f One or more of lithium transition metal oxides and their modified compounds. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes but is not limited to one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes but is not limited to one or more of N, F, S and Cl.

[0197] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.1 Al 0.05 One or more of O2, LiFePO4, and LiMnPO4.

[0198] During the charging and discharging process, Li undergoes insertion / extraction and consumption in a single secondary battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to a secondary battery cell, the molar Li content changes after charge-discharge cycles. Similarly, in the examples of positive electrode active materials in this disclosure, the molar O content is only a theoretical value. Lattice oxygen release causes changes in the molar O content, and the actual molar O content will also fluctuate.

[0199] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, with the general formula X p M' q (PO4) r O x Y 3-x One or more of the materials. In general formula X p M' q (PO4) r O x Y 3-x In this case, 0 < p ≤ 4, 0 < q ≤ 2, 1 ≤ r ≤ 3, 0 ≤ x ≤ 2, and X includes, but is not limited to, H. + Li + Na + K + and NH4 +One or more of the following, M' is a transition metal cation, optionally including but not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, optionally one or more of F, Cl and Br.

[0200] The modified compounds for the positive electrode active materials of the aforementioned lithium battery cells and sodium battery cells can be obtained by doping and / or surface coating modifications of the positive electrode active materials.

[0201] In some embodiments, the positive electrode film layer may further include a positive electrode conductive agent. As an example, the positive electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0202] In some embodiments, the positive electrode film layer may further include a positive electrode binder. As an example, the positive electrode binder may include, but is not limited to, one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resins.

[0203] In some embodiments, the positive current collector may be a metal foil or a composite current collector. An example of a metal foil is aluminum foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0204] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing positive electrode active materials, positive electrode conductive agents, positive electrode binders, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0205] [Negative electrode plate]

[0206] In some embodiments, the negative electrode sheet may include a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector and comprising a negative electrode active material. For example, the negative current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0207] The negative electrode active material may be any material known in the art for use in secondary battery cells. As an example, the negative electrode active material may include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may include, but are not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include, but are not limited to, one or more of elemental tin, tin oxide, and tin alloys.

[0208] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0209] In some embodiments, the negative electrode film layer may further include a negative electrode binder. As an example, the negative electrode binder may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0210] In some embodiments, the negative electrode film layer may also include other additives. As an example, other additives may include thickeners, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, etc.

[0211] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. As an example of a metal foil, copper foil may be used. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0212] The negative electrode film is typically formed by coating a negative electrode slurry onto a negative electrode current collector, followed by drying and cold pressing. The negative electrode slurry is usually formed by dispersing the negative electrode active material, negative electrode conductive agent, negative electrode binder, and other optional additives in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP) or deionized water, but is not limited to these.

[0213] The negative electrode sheet does not exclude other additional functional layers besides the negative electrode film layer. For example, in some embodiments, the negative electrode sheet also includes a conductive undercoat layer (e.g., composed of a conductive agent and a binder) sandwiched between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector.

[0214] In some embodiments, the negative electrode sheet can be made of foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, etc. When foamed metal is used as the negative electrode sheet, the surface of the foamed metal may or may not contain a negative electrode active material.

[0215] [Electrolytes]

[0216] The electrolyte plays a role in conducting ions between the positive and negative electrode plates.

[0217] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0218] Taking a lithium battery cell as an example, the electrolyte salt may include, but is not limited to, one or more of the following: lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalate borate (LiDFOB), lithium dioxalate borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0219] Taking sodium battery cells as an example, the electrolyte salt may include, but is not limited to, one or more of the following: sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium difluorosulfonyl imide (NaFSI), sodium difluoromethanesulfonyl imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalate borate (NaDFOB), sodium dioxalate borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0220] In some embodiments, the organic solvent may include, but is not limited to, one or more of the following: ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl ester carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ether.

[0221] In some embodiments, the electrolyte may also include additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain properties of the secondary battery cell, such as additives that improve overcharge performance, additives that improve high-temperature performance, additives that improve low-temperature performance, etc.

[0222] Optionally, the additive may include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), and ethylene sulfate (DTD).

[0223] Methods for preparing secondary battery cells are well known. In some embodiments, a positive electrode, a separator, a negative electrode, and an electrolyte can be assembled to form a secondary battery cell. As an example, the positive electrode, separator, and negative electrode can be formed into an electrode assembly through a winding process and / or a stacking process. The electrode assembly is placed in an outer packaging, dried, and then injected with the aforementioned electrolyte. After vacuum sealing, settling, and formation processes, a secondary battery cell is obtained.

[0224] Example

[0225] The following examples describe the contents of this disclosure in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on mass, and all reagents used in the examples are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0226] Example 1

[0227] Preparation of the separating membrane

[0228] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-methacryloyloxypropyltriethoxysilane, and 5g divinylbenzene. In a reactor, 210g deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 84°C for 1.5 hours of maturation. The product obtained from the emulsion polymerization reaction was dried in a vacuum drying oven at 105°C for 8 hours, and then transferred to a rotary kiln and baked at 180°C for 2 hours under a nitrogen atmosphere to obtain a block solid. The block solid was allowed to cool naturally in air, then crushed using an air jet mill, mixed with water, and wet-milled to obtain a dispersion of silicon-containing organic resin particles (No. 1).

[0229] The above dispersion, binder polymethyl methacrylate, and dispersant sodium carboxymethyl cellulose were stirred evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of the heat-resistant layer slurry containing silicone organic resin particles, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate was 90:2:8.

[0230] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0231] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0232] Preparation of secondary battery cells

[0233] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, positive electrode binder polyvinylidene fluoride (PVDF), and positive electrode conductive agent carbon black are added to N-methylpyrrolidone (NMP) in a mass ratio of 97:2:1 and thoroughly mixed to prepare a positive electrode slurry. The positive electrode slurry is then uniformly coated onto the positive electrode current collector aluminum foil, and subsequently dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0234] Artificial graphite (anode active material), acetylene black (anode conductive agent), styrene-butadiene rubber (SBR) (anode binder), and sodium carboxymethyl cellulose (thickener) were added to deionized water at a mass ratio of 96.0:1.5:1.5:1. After thorough mixing, a cathode slurry was prepared. The cathode slurry was then uniformly coated onto copper foil (anode current collector), and subsequently dried, cold-pressed, and slit to obtain the cathode sheet.

[0235] At 25°C, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7 to obtain a mixed solvent. LiPF6, vinylene carbonate (VC), and vinyl sulfate (DTD) were then dissolved in this mixed solvent to obtain the electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of VC was 2%, and the mass fraction of DTD was 3%, based on the mass of the electrolyte.

[0236] The positive electrode, separator, and negative electrode are stacked, wound, and hot-pressed in sequence to obtain an electrode assembly. The electrode assembly is then placed in a hard-shell outer packaging and subjected to processes such as electrolyte injection, settling, and formation to obtain a secondary battery cell.

[0237] Example 2

[0238] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0239] Preparation of the separating membrane

[0240] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-methacryloyloxypropyltriethoxysilane, and 5g divinylbenzene. In a reactor, 210g deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 84°C for 1.5 hours of maturation. The product obtained from the emulsion polymerization reaction was dried in a vacuum drying oven at 105°C for 8 hours, and then transferred to a rotary kiln and baked at 200°C for 2 hours under a nitrogen atmosphere to obtain a block solid. The block solid was allowed to cool naturally in air, then crushed using an air jet mill, mixed with water, and wet-milled to obtain a dispersion of silicon-containing organic resin particles (2#).

[0241] The above dispersion, binder polymethyl methacrylate, and dispersant sodium carboxymethyl cellulose were stirred evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of the heat-resistant layer slurry containing silicone organic resin particles, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate was 90:2:8.

[0242] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0243] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0244] Example 3

[0245] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0246] Preparation of the separating membrane

[0247] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-methacryloyloxypropyltriethoxysilane, and 5g divinylbenzene. In a reactor, 210g deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 84°C for 1.5 hours of maturation. The product obtained from the emulsion polymerization reaction was dried in a vacuum drying oven at 105°C for 8 hours, then transferred to a rotary kiln and baked at 220°C for 2 hours under a nitrogen atmosphere to obtain a block solid. The block solid was allowed to cool naturally in air, then crushed using an air jet mill, mixed with water, and wet-milled to obtain a dispersion of silicon-containing organic resin particles (No. 3).

[0248] The above dispersion, binder polymethyl methacrylate, and dispersant sodium carboxymethyl cellulose were stirred evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of the heat-resistant layer slurry containing silicone organic resin particles, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate was 90:2:8.

[0249] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0250] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0251] Example 4

[0252] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0253] Preparation of the separating membrane

[0254] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52g γ-methacryloyloxypropyltriisopropoxysilane, 3g 3-methacryloyloxypropyltriethoxysilane, and 5g divinylbenzene. In a reactor, 210g deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 84°C for 1.5 hours of maturation. The product obtained from the emulsion polymerization reaction was dried in a vacuum drying oven at 105°C for 8 hours, and then transferred to a rotary kiln and baked at 240°C for 2 hours under a nitrogen atmosphere to obtain a block solid. The block solid was allowed to cool naturally in air, then crushed using an air jet mill, mixed with water, and wet-milled to obtain a dispersion of silicon-containing organic resin particles (No. 4).

[0255] The above dispersion, binder polymethyl methacrylate, and dispersant sodium carboxymethyl cellulose were stirred evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of the heat-resistant layer slurry containing silicone organic resin particles, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate was 90:2:8.

[0256] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0257] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0258] Comparative Example 1

[0259] Except for the following differences, the preparation of the secondary battery cells is the same as in Example 1.

[0260] Preparation of the separating membrane

[0261] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, and 60g γ-methacryloyloxypropyltriisopropoxysilane. In a reactor, 210g of deionized water was added, and the temperature was raised to 70°C. Under nitrogen protection and stirring, the pre-emulsion was added dropwise. After reacting for 4 hours, the temperature was raised to 84°C and the reaction was allowed to mature for 1.5 hours to obtain a silicone-containing organic resin particle D1# emulsion.

[0262] The above emulsion, binder polymethyl methacrylate, and dispersant sodium carboxymethyl cellulose were stirred evenly in deionized water to obtain a heat-resistant layer slurry. The solid mass ratio of the heat-resistant layer slurry containing silicone organic resin particles, dispersant sodium carboxymethyl cellulose, and binder polymethyl methacrylate was 90:2:8.

[0263] Commercially available polyvinylidene fluoride granules, polymethyl methacrylate binder, sodium carboxymethyl cellulose dispersant, and ether-based surfactants were mixed evenly in deionized water at a solid content mass ratio of 87:8:3:2 to obtain the adhesive layer slurry.

[0264] A commercially available 7μm thick polyethylene microporous film was used as the porous base membrane. The heat-resistant layer slurry was coated onto both surfaces of the porous base membrane using a microgravure method. After drying, the adhesive layer slurry was sprayed onto the heat-resistant layer. Then, through drying and slitting processes, the release membrane was obtained.

[0265] The silicon-containing organic resin particles 1# to 4# prepared above meet the following characteristics: the silicon-containing organic resin particles have a network structure formed by carbon-carbon bonds as the main chain, and the side chains contain silicon-oxygen structures and benzene ring structures. They have no melting point and no glass transition temperature T below 300℃. g .

[0266] Performance testing

[0267] (1) Initial thermogravimetric temperature T of silicon-containing organic resin particles 3d test

[0268] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the alumina crucible of the thermogravimetric analyzer (TGA). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; temperature rise program: heating rate 10℃ / min, temperature range 35℃-600℃; obtain the temperature corresponding to a 3% loss of sample mass relative to the initial mass (i.e., 97% of the initial mass) from the test curve, which is the initial thermogravimetric temperature T. 3d .

[0269] (2) Cyclic voltammetry test of silicon-containing organic resin particles

[0270] Silicon-containing organic resin particles, polymethyl methacrylate binder, and conductive carbon black conductive agent were dissolved in water at a solid content mass ratio of 64:7:29 to prepare a slurry. This slurry was coated onto aluminum foil as the positive electrode, and lithium foil was used as the negative electrode to assemble a coin cell. Cyclic voltammetry (CV) was performed on the coin cell at a scan rate of 0.10 mV / s, a voltage range of 2.50 V–5.00 V, and three cycles. The voltage corresponding to the peak point of the first cyclic voltammetry curve was taken as the oxidation peak potential. The electrolyte used in the test was LiPF6 with a concentration of 1 mol / L. The solvent for the electrolyte was obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) at a volume ratio of 3:7.

[0271] (3) Thermal shrinkage rate test of the separator film

[0272] The heat shrinkage rate test of the release liner can be referenced in GB / T 36363-2018.

[0273] Cut the release film into samples with a width of 50mm and a length of 100mm using a punching machine. Take 5 parallel samples and place them on A4 paper. Then place the A4 paper containing the samples on corrugated paper with a thickness of 1mm to 5mm.

[0274] Set the temperature of the forced-air drying oven to 130℃. After the temperature reaches the set temperature and stabilizes for 60 minutes, place the A4 paper placed on the corrugated paper into the forced-air drying oven and start timing. After the set time (1 hour in this disclosure) is reached, measure the length and width of the isolation film, and mark the values ​​as a and b respectively.

[0275] Calculation of heat shrinkage rate: Longitudinal (MD) heat shrinkage rate = [(100-a) / 100]×100%, Transverse (TD) heat shrinkage rate = [(50-b) / 50]×100%, take the average value of 3 parallel samples as the test result.

[0276] (4) High-temperature storage performance test of secondary battery cells

[0277] At 25℃, a single secondary battery cell is charged at a constant current of 1 / 3C to 4.25V, then charged at a constant voltage of 4.25V to a current of 0.05C. After resting for 5 minutes, it is discharged at a constant current of 1 / 3C to 2.8V. The resulting discharge capacity is recorded as the initial capacity C0. Next, the cell is charged at a constant current of 1 / 3C to 4.25V, then charged at a constant voltage of 4.25V to a current of 0.05C. At this point, the cell is fully charged. The fully charged cell is stored in a 60℃ constant temperature chamber for 30 days. After the storage period, the cell is removed, and once its temperature drops to 25℃, it is discharged at a constant current of 1 / 3C to 2.8V. The resulting discharge capacity is recorded as the post-storage capacity C1. The capacity retention rate of a single secondary battery cell after 30 days of storage at 60℃ = (Post-storage capacity C1 / Initial storage capacity C0) × 100%.

[0278] Table 1

[0279]

[0280] The test results above show that the initial thermogravimetric temperature T is met. 3d Silicon-containing organic resin particles with a temperature range of 290℃-330℃ can effectively improve the heat resistance of the separator and the high-temperature storage performance of the secondary battery cells.

[0281] It should be noted that this disclosure is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same essential structure and achieving the same effect as the technical concept within the scope of this disclosure are included in the technical scope of this disclosure. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, are also included in the scope of this disclosure without departing from the spirit of this disclosure.

Claims

1. A silicon-containing organic resin particle, characterized in that, The initial thermogravimetric temperature T of the silicon-containing organic resin particles 3d The temperature ranges from 290℃ to 330℃.

2. The silicon-containing organic resin particles according to claim 1, characterized in that, The initial thermogravimetric temperature T of the silicon-containing organic resin particles 3d The temperature range is 300℃-330℃.

3. The silicon-containing organic resin particles according to any one of claims 1-2, characterized in that, The silicon-containing organic resin particles have no melting point; and / or, The silicon-containing organic resin particles have no glass transition temperature below 300°C.

4. The silicon-containing organic resin particles according to any one of claims 1-3, characterized in that, The dissolution rate of the silicon-containing organic resin particles after being soaked in a mixed solvent of ethylene carbonate and methyl ethyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%; and / or, The swelling degree of the silicon-containing organic resin particles after being immersed in a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3:7 at 60°C for 7 days is less than or equal to 3%; and / or, The cyclic voltammetry curve of the silicon-containing organic resin particles in the first cycle does not have an oxidation peak in the voltage range of 2.50V to 4.45V.

5. The silicon-containing organic resin particles according to any one of claims 1-4, characterized in that, The true density of the silicon-containing organic resin particles is 1.1 g / cm³. 3 -1.4g / cm 3 ; and / or, The silicon-containing organic resin particles comprise aggregates of primary particles; and / or, The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 300nm-800nm.

6. The silicon-containing organic resin particles according to claim 5, characterized in that, The primary particles in the agglomerate have a particle size of 30nm-250nm.

7. The silicon-containing organic resin particles according to any one of claims 1-6, characterized in that, The silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, which contain carbon-carbon bonds and silicon-oxygen structures.

8. The silicon-containing organic resin particles according to any one of claims 1-7, characterized in that, The silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles. The silicon-containing organic resin particles have a network structure formed with carbon-carbon bonds as the main chain and silicon-oxygen structures in the side chains.

9. The silicon-containing organic resin particles according to any one of claims 1-8, characterized in that, The silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, and the silicon-containing organic cross-linked resin particles include cross-linked structural units. Optionally, the crosslinked structural units include divinylbenzene structural units, diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, and di... The structural unit comprises one or more of the following: tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

10. A method for preparing silicon-containing organic resin particles, comprising the following steps: providing a pre-emulsion containing monomers, crosslinking agents, emulsifiers, initiators, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions, wherein the monomers include silane coupling agents containing alkenyl groups and / or acryloyloxy groups; drying the product obtained from the emulsion polymerization reaction, then baking it under an inert gas atmosphere, and then subjecting it to a crushing and grinding process to obtain silicon-containing organic resin particles.

11. The method according to claim 10, characterized in that, The product obtained from the emulsion polymerization reaction is dried at a temperature of 80℃-150℃; and / or, The product obtained from the emulsion polymerization reaction is dried for 2-12 hours.

12. The method according to any one of claims 10-11, characterized in that, The products obtained from emulsion polymerization can be dried by methods such as vacuum drying, spray drying, forced air drying, microwave drying, or fluidized bed drying.

13. The method according to any one of claims 10-12, characterized in that, The baking temperature is 160℃-250℃; and / or, The baking process is carried out at a temperature of 1-8 hours.

14. The method according to any one of claims 10-13, characterized in that, The grinding process includes the following steps: mixing the crushed material with a solvent, grinding media and optional dispersant to obtain a mixed slurry, and then grinding the mixed slurry to obtain silicon-containing organic resin particles.

15. The method according to claim 14, characterized in that, The grinding process satisfies at least one of the following conditions (1) to (6): (1) The solvent includes one or more of water, methanol, and ethanol; (2) The dispersant includes one or more of the following: polyacrylic acid type dispersant, carboxymethyl cellulose type dispersant, polyethylene glycol, polyvinyl alcohol, and polyvinylpyrrolidone; (3) The grinding media includes one or more of zirconium oxide balls, alumina balls, and silicon nitride balls; (4) The average particle size of the grinding media is 0.1 mm-2 mm; (5) The filling rate of the grinding media is 30%-80%; (6) The grinding speed is 500rpm-3000rpm.

16. The method according to any one of claims 10-15, characterized in that, The heating temperature during the ripening stage of the emulsion polymerization reaction is 70℃-95℃; and / or, The heating time for the ripening stage of the emulsion polymerization reaction is 1 hour to 5 hours; and / or, The inert gas includes one or more of nitrogen, argon, and helium.

17. The method according to any one of claims 10-16, characterized in that, The emulsion polymerization reaction includes the following steps: under the conditions of a first temperature, inert gas protection and stirring, the pre-emulsion is added dropwise to a reactor containing water, and after the first reaction time, the temperature is raised to the heating temperature of the maturation stage to carry out the maturation reaction, thereby obtaining silicon-containing organic resin particles.

18. The method according to claim 17, characterized in that, The first temperature is 55℃-70℃; and / or the first time is 3h-6h.

19. The method according to any one of claims 10-18, characterized in that, The monomers include γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-tert-butoxyvinylsilane, and vinyltri(β-methyl)silane. One or more of the following: (1-methylvinyl)oxysilane, vinyltris[(1-methylvinyl)oxy]silane, vinyltritert-butylperoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, methacryloyloxypropyldimethylmethoxysilane, (3-acryloyloxy)dimethylmethoxysilane, 3-methacryloyloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, 3-(methacryloyloxy)propylmethyldiethoxysilane; and / or, The crosslinking agent comprises one or more of the following: divinylbenzene, diethylene glycol divinyl ether, triethylene glycol divinyl ether, diallyl maleate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,8-octanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetraethylene glycol dimethacrylate, tripropylene glycol diacrylate, 2,2,4-trimethyladipyl di[2-ethylaziridinium], 1,1-azeloyl di[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium)propionate, trimethylolpropane-tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate; and / or, With the total mass of the monomer and the crosslinking agent being 100%, the mass fraction of the crosslinking agent is 1.5%-18%.

20. A dispersion of silicon-containing organic resin particles, characterized in that, It includes the silicon-containing organic resin particles and dispersant as described in any one of claims 1-9, or is obtained by the method described in any one of claims 10-19.

21. A separating membrane, comprising a porous base membrane and a porous coating located on at least one side of the porous base membrane, characterized in that, The porous coating comprises the silicon-containing organic resin particles according to any one of claims 1-9, or silicon-containing organic resin particles prepared by the method according to any one of claims 10-19.

22. The separator according to claim 21, characterized in that, Based on the total mass of the porous coating, the mass content of the silicon-containing organic resin particles in the porous coating is 50%-99%; and / or, The thickness of the porous coating is 0.5μm-5μm.

23. The separator according to any one of claims 21-22, characterized in that, The separator membrane, after being heated at a constant temperature of 130°C for 1 hour, exhibits a longitudinal thermal shrinkage rate of less than or equal to 1.5%; and / or, The separator membrane, when heated at a constant temperature of 130°C for 1 hour, exhibits a transverse thermal shrinkage rate of less than or equal to 1.5%.

24. A secondary battery cell, characterized in that, It includes a positive electrode, a negative electrode, and a separator as described in any one of claims 21-23, wherein the separator is disposed between the positive electrode and the negative electrode.

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

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

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