Silicon-containing organic resin particle and preparation method therefor, silicon-containing organic resin particle emulsion, separator, secondary battery cell, battery device, and electric device

Abstract

A silicon-containing organic resin particle and a preparation method therefor, a silicon-containing organic resin particle emulsion, a separator, a secondary battery cell, a battery device and an electric device. The separator comprises a porous base membrane and a coating located on at least one side of the porous base membrane, wherein the coating comprises silicon-containing organic resin particles, the volume median diameter Dv50 of the silicon-containing organic resin particles is 80-320 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is less than or equal to 1.7. The secondary battery cell has high reliability, a high mass energy density and good cycle performance.

Description

Silicon-containing organic resin particles and their preparation methods, silicon-containing organic resin particle emulsions, separators, secondary battery cells, battery devices and electrical devices.

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202410946443.3, filed on July 15, 2024, entitled “Organosilicon resin particles and preparation method thereof, separator membrane, battery cell, and electrical device”, and Chinese Patent Application No. 202411385737.X, filed on September 30, 2024, entitled “Silicone-containing organic resin particles and preparation method thereof, silicone-containing organic resin particle emulsion, separator membrane, secondary battery cell, battery device, and electrical device”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a silicon-containing organic resin particle and its preparation method, a silicon-containing organic resin particle emulsion, a separator, a secondary battery cell, a battery device, and an electrical device. Background Technology

[0004] As the application range of rechargeable battery cells becomes increasingly 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

[0005] This disclosure provides a silicon-containing organic resin particle and its preparation method, a silicon-containing organic resin particle emulsion, a separator, a secondary battery cell, a battery device, and an electrical device. The secondary battery cell has high reliability, high energy density, and good cycle performance.

[0006] In a first aspect, this disclosure provides a separating membrane, comprising a porous base membrane and a coating located on at least one side of the porous base membrane, the coating comprising silicon-containing organic resin particles, wherein the volume distribution particle size Dv50 of the silicon-containing organic resin particles is 80nm-320nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is less than or equal to 1.7.

[0007] Silicon-containing organic resin particles have a low density, and secondary battery cells using them can have a higher mass energy density.

[0008] The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 80nm-320nm, which allows the coating to have a large number of particle stacks within a limited thickness range. When used in separators, this can improve the heat resistance of the separator and enhance the reliability of secondary battery cells.

[0009] The particle size distribution (Dv90-Dv10) / Dv50 reflects the degree to which the particle size of larger particles deviates from Dv50 and the particle size of smaller particles. The particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is less than or equal to 1.7. This facilitates the close packing of the silicon-containing organic resin particles, which, when used in separators, can improve the heat resistance of the separator and the reliability of the secondary battery cells; it can also give the separator good air permeability, resulting in good cycle performance of the secondary battery cells.

[0010] Therefore, the separator disclosed herein enables secondary battery cells to possess high reliability, high energy density, and good cycle performance.

[0011] In some embodiments, the particle size distribution (Dv90-Dv10) / Dv50 of the silicone-containing organic resin particles is 0.2 to 0.7. Having the volume distribution particle size of the silicone-containing organic resin particles within this range allows the separator membrane to better combine high heat resistance and high air permeability, and also enables the coating to have higher adhesion strength to the porous base membrane.

[0012] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles is 85nm-260nm. A volume distribution particle size Dv50 within this range allows the coating to achieve better uniformity without clogging pores; it can also further improve the heat resistance of the separator and the reliability of the secondary battery cell; and it is also beneficial for the separator to have lower impedance, thereby improving the cycle performance of the secondary battery cell.

[0013] In some embodiments, the volume distribution particle size Dv10 of the silicon-containing organic resin particles is 50nm-120nm.

[0014] In some embodiments, the volume distribution particle size Dv90 of the silicon-containing organic resin particles is 130nm-500nm.

[0015] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles.

[0016] In some embodiments, the silicon-containing organic resin particles contain a benzene ring structure.

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

[0018] In some embodiments, the silicon-containing organic resin particles include Si, O, C, and H elements.

[0019] In some embodiments, the mass fraction of Si element in the silicon-containing organic resin particles is 10%-25%.

[0020] In some embodiments, the mass fraction of oxygen in the silicon-containing organic resin particles is 10%-30%.

[0021] In some embodiments, the mass fraction of carbon element in the silicon-containing organic resin particles is 50%-62%.

[0022] In some embodiments, the mass fraction of hydrogen element in the silicon-containing organic resin particles is 5%-10%.

[0023] In some embodiments, the silicon-containing organic crosslinked resin particles include crosslinked structural units, wherein the crosslinked structural units include divinylbenzene structural units.

[0024] Optionally, the crosslinking structural unit further includes diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, and tripropylene glycol diacetate structural units. One or more of the following structural units: diacrylate, 2,2,4-trimethyladipyldi[2-ethylaziridinium], 1,1-azeloyldi[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0025] 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 that they have good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the separator, improving the heat resistance of the separator, and enhancing the reliability of the secondary battery cells.

[0026] In some embodiments, the silicon-containing organic resin particles have no melting point. The fact that the silicon-containing organic resin particles of this disclosure have no melting point indicates that they possess good heat resistance and thermal stability, thereby better resisting the thermal shrinkage of the separator, improving the heat resistance of the separator, and enhancing the reliability of the secondary battery cells.

[0027] In some embodiments, the true density of the silicon-containing organic resin particles is 1.2 g / cm³.3 -1.5g / cm 3 This allows secondary battery cells using the separator membrane disclosed herein to have a higher mass energy density.

[0028] In some embodiments, the mass content of the silicone organic resin particles in the coating is 50%-99% based on the total mass of the coating.

[0029] In some embodiments, the thickness of the coating is 0.5 μm-5 μm.

[0030] In some embodiments, the areal density of the coating is 0.5 g / m³. 2 -5g / m 2 .

[0031] In some embodiments, the ratio of the volume distribution particle size Dv50 of the silicon-containing organic resin particles to the average pore size of the porous base membrane is greater than or equal to 1.1.

[0032] 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 1.75%.

[0033] 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 1.75%.

[0034] In some embodiments, the air permeability of the isolation membrane is 170s / 100ml-230s / 100ml.

[0035] In some embodiments, the peel force between the coating and the porous base film is greater than or equal to 28 N / m.

[0036] Secondly, this disclosure provides a silicon-containing organic resin particle, wherein the volume distribution particle size Dv50 of the silicon-containing organic resin particle is 80nm-320nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particle is less than or equal to 1.7.

[0037] In some embodiments, the particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is 0.2 to 0.7.

[0038] In some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles is 85nm-260nm.

[0039] In some embodiments, the volume distribution particle size Dv10 of the silicon-containing organic resin particles is 50nm-120nm.

[0040] In some embodiments, the volume distribution particle size Dv90 of the silicon-containing organic resin particles is 130nm-500nm.

[0041] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles.

[0042] In some embodiments, the silicon-containing organic resin particles contain a benzene ring structure.

[0043] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, and the silicon-containing organic resin particles are a network structure formed with carbon-carbon bonds as the main chain, and the side chains contain benzene ring structures and silicon-oxygen structures.

[0044] In some embodiments, the silicon-containing organic resin particles include Si, O, C, and H elements.

[0045] In some embodiments, the mass fraction of Si element in the silicon-containing organic resin particles is 10%-25%.

[0046] In some embodiments, the mass fraction of oxygen in the silicon-containing organic resin particles is 10%-30%.

[0047] In some embodiments, the mass fraction of carbon element in the silicon-containing organic resin particles is 50%-62%.

[0048] In some embodiments, the mass fraction of hydrogen element in the silicon-containing organic resin particles is 5%-10%.

[0049] In some embodiments, the silicon-containing organic crosslinked resin particles include crosslinked structural units, wherein the crosslinked structural units include divinylbenzene structural units.

[0050] Optionally, the crosslinking structural unit further includes diethylene glycol divinyl ether structural units, triethylene glycol divinyl ether structural units, diallyl maleate structural units, ethylene glycol dimethacrylate structural units, 1,4-butanediol diacrylate structural units, 1,6-hexanediol diacrylate structural units, 1,8-octanediol diacrylate structural units, trimethylolpropane triacrylate structural units, pentaerythritol trimethacrylate structural units, tetraethylene glycol dimethacrylate structural units, and tripropylene glycol diacetate structural units. One or more of the following structural units: diacrylate, 2,2,4-trimethyladipyldi[2-ethylaziridinium], 1,1-azeloyldi[2-methylaziridinium], 1,1-(1,3-phenylene dicarbonyl)di[2-methylaziridinium], trimethylolpropane tris(2-methyl-1-aziridinium propionate), trimethylolpropane tris[3-(2-methylaziridinium)propionate], and pentaerythritol tris(3-aziridinium)propionate.

[0051] In some embodiments, the silicon-containing organic resin particles have no glass transition temperature below 300°C.

[0052] In some embodiments, the silicon-containing organic resin particles have no melting point.

[0053] In some embodiments, the true density of the silicon-containing organic resin particles is 1.2 g / cm³. 3 -1.5g / cm 3 .

[0054] Thirdly, this disclosure provides a method for preparing silicon-containing organic resin particles, comprising the following steps: providing a pre-emulsion containing a monomer of Formula I, an additive of Formula II, a crosslinking agent, an emulsifier, an initiator, and water; carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain silicon-containing organic resin particles; wherein R1, R2, and R3 are independently selected from C1-C4 alkyl, C2-C4 alkenyl, and C3-C12 trialkylsilyl, respectively; R4 is selected from C2 to C8 alkenyl or C4 to C8 (meth)acryloyloxyalkyl; one or both of R5, R6, and R7 are independently selected from H, C1-C4 alkyl, C2-C4 alkenyl, and C3-C12 trialkylsilyl, respectively; the remainder are selected from C1-C8 alkoxy; and R8 is selected from C2 to C8 alkenyl or C4 to C8 (meth)acryloyloxyalkyl.

[0055] With the total mass of the monomer shown in Formula I, the additive shown in Formula II, and the crosslinking agent being 100%, the mass fraction of the additive shown in Formula II is 2%-13.5%.

[0056] In some embodiments, the monomer represented by Formula I includes one or more of 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, vinyltris(β-methoxyethoxy)silane, ethylenetris[(1-methylvinyl)oxy]silane, and vinyltri-tert-butylperoxysilane.

[0057] In some embodiments, the additive represented by Formula II includes one or more of 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, methacryloxypropylmethyldimethoxysilane, (3-acryloxy)dimethylmethoxysilane, 3-methacryloxypropylmethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloxy)propylmethyldiethoxysilane.

[0058] In some embodiments, the emulsifier includes 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.

[0059] In some embodiments, the emulsifier has a mass fraction of 0.5%-10% based on the total mass of the monomer shown in Formula I, the additive shown in Formula II, and the crosslinking agent, which is 100%.

[0060] 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.

[0061] In some embodiments, the mass fraction of the crosslinking agent is 3%-18%, based on the total mass of the monomer shown in Formula I, the additive shown in Formula II, and the crosslinking agent as 100%.

[0062] In some embodiments, the heating temperature of the emulsion polymerization maturation stage is 75°C-92°C; and / or, the heating time of the emulsion polymerization maturation stage is 1h-5h.

[0063] In some embodiments, the emulsion polymerization reaction includes the following steps: under a first heating 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.

[0064] Optionally, the first heating temperature is 55℃-70℃.

[0065] Optionally, the first time period is 3h-6h.

[0066] Fourthly, this disclosure provides a silicone-containing organic resin particle emulsion, which includes the silicone-containing organic resin particles of the second aspect, or is obtained by the method of the third aspect.

[0067] Fifthly, this disclosure provides a secondary battery cell, which includes a positive electrode, a negative electrode, and a separator according to the first aspect of this disclosure, wherein the separator is disposed between the positive electrode and the negative electrode.

[0068] 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.

[0069] 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 of this disclosure. Attached Figure Description

[0070] 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.

[0071] Figure 1 shows a schematic diagram of a secondary battery cell provided in some embodiments of this disclosure.

[0072] Figure 2 shows a schematic diagram of an electrical device provided in some embodiments of this disclosure.

[0073] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0074] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the silicon-containing organic resin particles, their preparation methods, silicon-containing organic resin particle emulsions, 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 to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter of the claims.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] In this disclosure, the terms "multiple" or "a variety" refer to two or more kinds.

[0081] 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.

[0082] Unless otherwise stated, the test temperature for all parameters mentioned in this disclosure is 25°C.

[0083] The secondary battery cell mentioned in the embodiments of this disclosure can independently perform charge and discharge functions. After discharge, it can be recharged to activate the active materials and continue to be used. The secondary battery cell can be cylindrical, cuboid, or other shapes, etc., and the embodiments of this disclosure are not limited to this. Figure 1 shows a cuboid secondary battery cell 5 as an example.

[0084] 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.

[0085] 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).

[0086] 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.

[0087] In some embodiments, a battery cell assembly is typically formed by arranging multiple secondary battery cells.

[0088] 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.

[0089] 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.

[0090] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0091] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple secondary battery cells to the housing.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] Figure 2 is a schematic diagram of an example electrical device. This electrical device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0097] In the context of this disclosure, the "silicone-containing organic resin particles" primarily serve to improve heat resistance in the coating of the release liner, and have virtually no adhesive effect.

[0098] The separator is a crucial component supporting the electrochemical processes of charging and discharging in 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 cell. To improve the heat resistance of the separator, a 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 cell.

[0099] 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 reliability, high energy density, and good cycle performance.

[0100] The volume distribution particle size Dv50 of the silicon-containing organic resin particles disclosed herein is 80nm-320nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is less than or equal to 1.7.

[0101] Silicon-containing organic resin particles have a low density, and secondary battery cells using them can have a higher mass energy density.

[0102] The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 80nm-320nm, which allows the coating to have a large number of particle stacks within a limited thickness range. When used in separators, this can improve the heat resistance of the separator and enhance the reliability of secondary battery cells.

[0103] The particle size distribution (Dv90-Dv10) / Dv50 reflects the degree to which the particle size of larger particles deviates from Dv50 and the particle size of smaller particles. The particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is less than or equal to 1.7. This facilitates the close packing of the silicon-containing organic resin particles, which, when used in separators, can improve the heat resistance of the separator and the reliability of the secondary battery cells; it can also give the separator good air permeability, resulting in good cycle performance of the secondary battery cells.

[0104] Therefore, the silicon-containing organic resin particles disclosed herein, when used in a separator membrane, enable secondary battery cells to possess high reliability, high energy density, and good cycle performance.

[0105] The particle size distribution (Dv90-Dv10) / Dv50 of the silicone organic resin particles is less than or equal to 1.7. In some embodiments, the particle size distribution (Dv90-Dv10) / Dv50 of the silicone organic resin particles can be 0.2-1.7, for example, it can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, or any range of the above values.

[0106] Limited by current polymerization production processes, the minimum achievable particle size distribution (Dv90-Dv10) / Dv50 of silicone organic resin particles is 0.2.

[0107] Optionally, in some embodiments, the particle size distribution (Dv90-Dv10) / Dv50 of the silicone organic resin particles can be 0.2 to 1.5, 0.2 to 1.2, 0.2 to 1, 0.2 to 0.8, 0.2 to 0.7, 0.2 to 0.6, 0.2 to 0.5, or 0.2 to 0.4.

[0108] The volume distribution and particle size of the silicone organic resin particles are within the above range, which can make the separator membrane better combine high heat resistance and high air permeability, and can also make the coating and the porous base membrane have high adhesion strength.

[0109] The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 80nm-320nm, for example, it can be 80nm, 85nm, 90nm, 95nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 310nm, 320nm, or any combination of the above values.

[0110] Optionally, in some embodiments, the volume distribution particle size Dv50 of the silicon-containing organic resin particles can be 85nm-260nm, 85nm-240nm, 85nm-220nm, 85nm-200nm, 85nm-180nm, 90nm-260nm, 90nm-240nm, 90nm-220nm, 90nm-200nm, 90nm-180nm, 95nm-260nm, 95nm-240nm, 95nm-220nm, 95nm-200nm, or 95nm-180nm.

[0111] When the volume distribution particle size Dv50 of the silicon-containing organic resin particles is within the above range, the coating can achieve better coating uniformity without clogging pores; it can also further improve the heat resistance of the separator and the reliability of the secondary battery cell; it is also beneficial for the separator to have lower impedance, thereby improving the cycle performance of the secondary battery cell.

[0112] In some embodiments, the volume distribution particle size Dv10 of the silicon-containing organic resin particles can be 50nm-120nm, for example, it can be 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 105nm, 110nm, 115nm, 120nm, or any range of the above values.

[0113] Optionally, the volume distribution particle size Dv10 of the silicon-containing organic resin particles can be 55nm-115nm, 60nm-115nm, 65nm-115nm, or 70nm-115nm.

[0114] In some embodiments, the volume distribution particle size Dv90 of the silicon-containing organic resin particles can be 130nm-500nm, for example, it can be 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 230nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, or any combination of the above values.

[0115] Optionally, the volume distribution particle size Dv90 of the silicon-containing organic resin particles can be 130nm-460nm, 130nm-440nm, 130nm-420nm, 130nm-400nm, 130nm-380nm, 130nm-360nm, 130nm-340nm, 130nm-320nm, 130nm-300nm, 130nm-280nm, 130nm-260nm, 130nm-240nm, or 130nm-200nm.

[0116] The volume distribution particle size of the silicon-containing organic resin particles is within the above range, which is beneficial to further improve the heat resistance of the separator and the reliability of the secondary battery cell; it is also beneficial to have a lower impedance in the separator, which can further improve the cycle performance of the secondary battery cell.

[0117] Dv10, Dv50, and Dv90 represent the particle sizes corresponding to a cumulative volumetric distribution percentage of 10%, 50%, and 90%, respectively. These values ​​can be determined using a laser particle size analyzer, referring to GB / T 19077-2016. During testing, add 1g of the sample to a clean small beaker and 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, 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.

[0118] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles.

[0119] In some embodiments, the silicone-containing organic resin particles contain carbon-carbon bonds and silicon-oxygen structures.

[0120] In some embodiments, the silicone-containing organic resin particles contain a benzene ring structure. The benzene ring structure is highly rigid, which gives the silicone-containing organic resin particles good heat resistance.

[0121] In some embodiments, the silicon-containing organic resin particles form a network structure with carbon-carbon bonds as the main chain and silicon-oxygen structures in the side chains. Therefore, the silicon-containing organic resin particles of this disclosure can have better heat resistance, better resist the thermal shrinkage of the separator, improve the heat resistance of the separator, and enhance the reliability of the secondary battery cell.

[0122] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, and the silicon-containing organic resin particles have a network structure formed with carbon-carbon bonds as the main chain, and the side chains contain benzene ring structures and silicon-oxygen structures. Therefore, the silicon-containing organic resin particles of this disclosure can have better heat resistance, better resist the thermal shrinkage of the separator, improve the heat resistance of the separator, and improve the reliability of the secondary battery cell.

[0123] In some embodiments, the silicon-containing organic resin particles include Si, O, C, and H elements.

[0124] Optionally, the mass fraction of Si in the silicon-containing organic resin particles can be 10%-25%.

[0125] Optionally, the mass fraction of oxygen in the silicon-containing organic resin particles can be 10%-30%.

[0126] Optionally, the mass fraction of carbon in the silicon-containing organic resin particles can be 50%-62%.

[0127] Optionally, the mass fraction of hydrogen in the silicon-containing organic resin particles can be 5%-10%.

[0128] In some embodiments, the silicon-containing organic resin particles are silicon-containing organic cross-linked resin particles, which include cross-linked structural units, and the cross-linked structural units may include divinylbenzene structural units.

[0129] 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.

[0130] In some embodiments, the true density of the silicone-containing organic resin particles can be 1.2 g / cm³. 3 -1.5g / cm 3 .

[0131] 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.

[0132] In some embodiments, the silicone-containing organic resin particles are poorly soluble in both water and organic solvents, such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), and chloroform, at 25°C. They are also insoluble in the mobile phase used in gel permeation chromatography and the molecular weight of the silicone-containing organic resin particles cannot be determined by gel permeation chromatography.

[0133] In some embodiments, the silicone-containing organic resin particles have no glass transition temperature below 300°C.

[0134] Silicon-containing organic resin particles have no glass transition temperature below 300℃, indicating that they have good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of the separator, improve the heat resistance of the separator, and enhance the reliability of the secondary battery cells.

[0135] Glass transition temperature T gThe test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The DSC curve can be used to determine whether the silicon-containing organic resin particles have a glass transition temperature T below 300℃. g .

[0136] 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.

[0137] 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℃.

[0138] In some embodiments, the silicone-containing organic resin particles have no melting point.

[0139] The silicon-containing organic resin particles disclosed herein have no melting point, indicating that the silicon-containing organic resin particles have good heat resistance and thermal stability. This can better resist the thermal shrinkage of the separator, improve the heat resistance of the separator, and improve the reliability of the secondary battery cell.

[0140] 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.

[0141] This disclosure also provides a method for preparing silicon-containing organic resin particles, which can prepare the above-mentioned silicon-containing organic resin particles.

[0142] The preparation method of silicon-containing organic resin particles includes the following steps: providing a pre-emulsion containing a monomer shown in Formula I, an additive shown in Formula II, a crosslinking agent, an emulsifier, an initiator, and water, and carrying out an emulsion polymerization reaction under heating, inert gas protection, and stirring conditions to obtain silicon-containing organic resin particles.

[0143] R1, R2, and R3 are each independently selected from C1-C4 alkyl, C2-C4 alkenyl, and C3-C12 trialkylsilyl groups, respectively; R4 is selected from C2 to C8 alkenyl or C4 to C8 (meth)acryloyloxyalkyl; one or both of R5, R6, and R7 are each independently selected from H, C1-C4 alkyl, C2-C4 alkenyl, and C3-C12 trialkylsilyl groups, respectively; the remainder are selected from C1-C8 alkoxy groups; and R8 is selected from C2 to C8 alkenyl or C4 to C8 (meth)acryloyloxyalkyl.

[0144] With the total mass of the monomer shown in Formula I, the additive shown in Formula II, and the crosslinking agent being 100%, the mass fraction of the additive shown in Formula II is 2%-13.5%.

[0145] Due to limitations in current polymerization processes, silicone-containing organic resin particles suffer from a wide particle size distribution. However, in the preparation method disclosed herein, the pre-emulsion utilizes monomers of Formula I and additives of Formula II with different activities. By combining these two and reacting them with a crosslinking agent, a three-dimensional crosslinked network structure can be formed, resulting in silicone-containing organic resin particles with a narrow particle size distribution. Furthermore, both the monomers of Formula I and the additives of Formula II can undergo crosslinking reactions on their own, with each other, and with the crosslinking agent. This results in silicone-containing organic resin particles with good heat resistance, making them less prone to softening or deformation.

[0146] By adjusting the mass fraction of the additive shown in Formula II, the volume distribution particle size of the silicon-containing organic resin particles can be reduced, and the resulting volume distribution particle size Dv50 of the silicon-containing organic resin particles can be less than or equal to 320 nm.

[0147] Therefore, the preparation method provided in this disclosure can prepare silicon-containing organic resin particles with small particle size, narrow particle size distribution and good heat resistance.

[0148] The mass fraction of the additive shown in Formula II can be 2%-13.5%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13.5%, or any combination of the above values.

[0149] Optionally, based on the total mass of the monomer shown in Formula I, the additive shown in Formula II, and the crosslinking agent as 100%, the mass fraction of the additive shown in Formula II can be 5%-10%.

[0150] In some embodiments, the monomer represented by Formula I may include one or more of the following: γ-methacryloxypropyltris(trimethylsiloxane), (3-acryloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane, γ-methacryloxypropyltriisopropoxysilane, 3-(acryloxy)propyltrimethoxysilane, 3-methacryloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tritert-butoxyvinylsilane, vinyltris(β-methoxyethoxy)silane, ethylenetris[(1-methylvinyl)oxy]silane, and vinyltritert-butylperoxysilane.

[0151] In some embodiments, the additive shown in Formula II may include one or more of 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, methacryloxypropylmethyldimethoxysilane, (3-acryloxy)dimethylmethoxysilane, 3-methacryloxypropylmethylethoxysilane, diethylmethylvinylsilane, vinyldimethylethoxysilane, methylvinyldiethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, methylvinyldimethoxysilane, and 3-(methacryloxy)propylmethyldiethoxysilane.

[0152] By adjusting the types of monomers shown in Formula I and / or additives shown in Formula II, the particle size and particle size distribution of silicon-containing organic resin particles can be further reduced, and the heat resistance of silicon-containing organic resin particles can also be improved.

[0153] The crosslinking agent and monomers polymerize to form crosslinked structural units of silicon-containing organic crosslinked resin particles.

[0154] In some embodiments, 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.

[0155] Optionally, the crosslinking agent may include divinylbenzene.

[0156] 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.

[0157] In some embodiments, based on the total mass of the monomer shown in Formula I, the additive shown in Formula II, and the crosslinking agent as 100%, the mass fraction of the crosslinking agent can be 3%-18%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, or any range of the above values.

[0158] When the quality of the crosslinking agent is within the above range, the heat resistance of the silicone-containing organic resin particles can be further improved.

[0159] In some embodiments, the emulsifier may be one or more of alkyl sulfates, alkyl sulfonates, Tween emulsifiers, fatty alcohol polyoxyethylene ethers, fatty alcohol polyoxypropylene ethers, cetearyl alcohol polyethers, and oleyl alcohol polyethers.

[0160] Optionally, the emulsifier may include one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, Tween 20, Tween 40, lauryl ether-7, lauryl ether-9, lauryl ether-10, and oleyl ether-10.

[0161] In some embodiments, the mass fraction of the emulsifier can be 0.5%-10% based on the total mass of the monomer shown in Formula I, the additive shown in Formula II, and the crosslinking agent as 100%, for example, it can be 0.5%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any combination of the above values.

[0162] Optionally, based on the total mass of the monomers shown in Formula I, the additives shown in Formula II, and the crosslinking agent as 100%, the mass fraction of the emulsifier can be 1.5%-10%, 1.5%-8%, 1.5%-6%, or 1.5%-5%.

[0163] 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.

[0164] In some embodiments, the heating temperature during the ripening stage of the emulsion polymerization reaction can be 75℃-92℃, for example, it can be 75℃, 76℃, 77℃, 78℃, 79℃, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, 91℃, 92℃, or any range of the above values.

[0165] 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.

[0166] In some embodiments, the emulsion polymerization reaction may include the following steps: adding a pre-emulsion dropwise into a reactor containing water under a first heating temperature, inert gas protection, and stirring conditions; after a first reaction time, raising the temperature to the heating temperature of the maturation stage to carry out a maturation reaction, thereby obtaining silicon-containing organic resin particles.

[0167] Optionally, the first heating temperature can be 55℃-70℃.

[0168] Optionally, the first time can be 3h-6h.

[0169] 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, potassium bicarbonate, sodium hydroxide, ammonia, etc.

[0170] In some embodiments, the method for preparing silicone organic resin particles further includes a demagnetization treatment step after the emulsion polymerization reaction is completed.

[0171] This disclosure also provides a silicone-containing organic resin particle emulsion.

[0172] The silicone-containing organic resin particle emulsion includes the silicone-containing organic resin particles of this disclosure, or is obtained by the preparation method of the silicone-containing organic resin particles of this disclosure.

[0173] This disclosure also provides a separator membrane. The separator membrane includes a porous base membrane and a coating located on at least one side of the porous base membrane. The coating includes an adhesive and silicon-containing organic resin particles of this disclosure or silicon-containing organic resin particles prepared by the method of this disclosure.

[0174] Both the porous base membrane and the coating have a porous structure, which gives the separator good air permeability and facilitates ion passage. The silicon-containing organic resin particles in the coating are interconnected and fixed by a binder, and the gaps between the silicon-containing organic resin particles can form a porous structure.

[0175] In some embodiments, the mass content of silicone organic resin particles in the coating may be 50%-99% based on the total mass of the coating.

[0176] Optionally, the mass content of the silicone organic resin particles in the coating can be 60%-99%, 70%-99%, 80%-99%, 85%-99%, 88%-99%, 80%-97%, 85%-97%, 88%-97%, 80%-95%, 85%-95%, or 88%-95%.

[0177] In some embodiments, the binder in the coating may include, but is not limited to, one or more of the following: polyacrylate binders, nitrile rubber binders, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0178] In some embodiments, the coating may also include a dispersant, such as, but not limited to, polyacrylic acid dispersants or carboxymethyl cellulose dispersants. As an example, the dispersant may include, but is not limited to, one or more of sodium carboxymethyl cellulose, sodium polyacrylate, and ammonium polyacrylate.

[0179] In some embodiments, the separator may also include polymer binder particles.

[0180] 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 high-temperature resistance.

[0181] In some embodiments, polymer binder particles may be embedded in silicone-containing organic resin particles and form protrusions on the coating surface.

[0182] In other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on the porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the heat-resistant layer 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.

[0183] In some other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer, the heat-resistant layer being disposed on one side of the porous base membrane, the adhesive layer being disposed on at least a portion of the surface of the other side of the porous base membrane, silicone organic resin particles being disposed in the heat-resistant layer, and polymer adhesive particles being disposed in the adhesive layer.

[0184] In some embodiments, the average particle size of the polymer binder particles can be 6 μm-18 μm.

[0185] 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.

[0186] Comonomers may include at least one of olefin monomers, fluorinated olefin monomers, chlorinated olefin monomers, acrylate monomers, acrylic monomers, and fluoroether monomers.

[0187] 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).

[0188] In some embodiments, the coating thickness can be 0.5 μm-5 μm. The coating thickness refers to the thickness of the coating on one side of the porous base film. Optionally, the coating thickness can be 0.5 μm-4 μm, 0.5 μm-3 μm, 0.5 μm-2 μm, 0.8 μm-4 μm, 0.8 μm-3 μm, or 0.8 μm-2 μm.

[0189] In some embodiments, the areal density of the coating may be 0.5 g / m³. 2 -5g / m2 .

[0190] 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.

[0191] 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.

[0192] In some embodiments, the thickness of the porous base film can be 4μm-12μm, and optionally 4μm-9μm.

[0193] In some embodiments, the porosity of the porous base membrane can be 25%-60%, optionally 28%-50%.

[0194] In some embodiments, the ratio of the volume distribution particle size Dv50 of the silicon-containing organic resin particles to the average pore size of the porous base membrane can be greater than or equal to 1.1.

[0195] The volume distribution particle size Dv50 of the silicon-containing organic resin particles has the same unit, e.g., nm, as the average pore size of the porous base membrane.

[0196] This can reduce pore blockage and improve the air permeability and ion conduction properties of the separator.

[0197] In some embodiments, the average pore size of the porous base film can be 25 nm to 82 nm.

[0198] The average pore size of the porous membrane can be measured using a capillary porosity analyzer (bubble point method). An exemplary testing method is as follows: Take a circular sample with a diameter of 25 mm, and drop 3-5 drops of wetting solution onto it. After the sample is completely wetted, place it in a mold. Then, use an inert gas (such as nitrogen) to compress the wetting solution in the pores of the sample. The compression pressure and flow rate are inversely proportional to the pore size. The average pore size of the sample is obtained through software sampling and pressure-pore size conversion analysis. The testing instrument can be a PMI CFP 1500 pore size analyzer, with a testing pressure ranging from 100 psi to 350 psi.

[0199] 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.

[0200] In some embodiments, the longitudinal (MD) thermal shrinkage rate of the separator film can be less than or equal to 1.75% when heated at a constant temperature of 130°C for 1 hour.

[0201] In some embodiments, the transverse (TD) heat shrinkage rate of the separator film can be less than or equal to 1.75% after being heated at a constant temperature of 130°C for 1 hour.

[0202] In some embodiments, the air permeability of the separator membrane can be 170s / 100ml-230s / 100ml.

[0203] In some embodiments, the peel force between the coating of the separator and the porous base membrane can be greater than or equal to 28 N / m.

[0204] The peel force between the coating of the separator and the porous base membrane can be tested as follows: Cut the separator into three 2.5cm × 15cm strips, attach the strips to a test steel plate, and attach a 2cm wide test tape to the side of the separator to be tested. Use a tensile testing machine, clamping the steel plate on one side and the tape on the other, to perform a 180° peel test. Take the average peel force of the three strips as the peel force between the separator coating and the porous base membrane. The tensile rate is 50mm / min.

[0205] It should be noted that the coating parameters of the above-mentioned separators are coating parameters for one side of the porous base membrane. When the coating is applied to both sides of the porous base membrane, if the coating parameters of either side meet the requirements of this disclosure, it is considered to fall within the protection scope of this disclosure.

[0206] The separator membrane can be prepared according to methods known in the art.

[0207] In some embodiments, a slurry comprising silicone organic resin particles and a binder may be applied to at least one side of a porous base membrane, and after drying, a separation membrane is obtained.

[0208] 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 coating surface.

[0209] 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.

[0210] 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.

[0211] In some embodiments, the solvent for the slurry may be water, such as deionized water.

[0212] In some embodiments, the slurry may also include dispersants and / or wetting agents, etc.

[0213] This disclosure also provides a secondary battery cell. The secondary battery cell includes the separator provided in this disclosure. This allows the secondary battery cell to possess high reliability, high energy density, and good cycle performance.

[0214] 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.

[0215] 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.

[0216] [Positive electrode plate]

[0217] 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.

[0218] 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 Coc 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.

[0219] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.1 Al 0.05 One or more of O2, LiFePO4, and LiMnPO4.

[0220] 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.

[0221] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn1 / 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] [Negative electrode plate]

[0228] 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.

[0229] 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.

[0230] 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.

[0231] 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).

[0232] 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.

[0233] 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.

[0234] 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.

[0235] 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.

[0236] 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.

[0237] [Electrolytes]

[0238] The electrolyte plays a role in conducting ions between the positive and negative electrode plates.

[0239] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0240] 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).

[0241] 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).

[0242] 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.

[0243] 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.

[0244] Optionally, the additive may include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), and ethylene sulfate (DTD).

[0245] 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.

[0246] Example

[0247] The following embodiments describe the disclosure of this disclosure in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0248] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 54g 3-methacryloyloxypropyltrimethoxysilane, 3g 3-methacryloyloxypropylmethyldimethoxysilane, and 3g divinylbenzene. In a reactor, 210g of deionized water was added, the temperature was raised to 70°C, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78°C and the reaction was allowed to mature for 1 hour to obtain the silicon-containing organic resin particle emulsion #1.

[0249] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 52.2g 3-methacryloyloxypropyltrimethoxysilane, 4.8g 3-methacryloyloxypropylmethyldimethoxysilane, and 3g divinylbenzene. In a reactor, 210g of deionized water was added, the temperature was raised to 70℃, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78℃ for 1 hour of maturation to obtain the silicon-containing organic resin particle emulsion #2.

[0250] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 51g 3-methacryloyloxypropyltrimethoxysilane, 6g 3-methacryloyloxypropylmethyldimethoxysilane, and 3g divinylbenzene. In a reactor, 210g of deionized water was added, the temperature was raised to 70°C, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78°C and the reaction was allowed to mature for 1 hour to obtain the silicon-containing organic resin particle emulsion #3.

[0251] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 49g 3-methacryloyloxypropyltrimethoxysilane, 8g 3-methacryloyloxypropylmethyldimethoxysilane, and 3g divinylbenzene. In a reactor, 210g of deionized water was added, the temperature was raised to 70℃, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78℃ for 1 hour of maturation to obtain the silicon-containing organic resin particle emulsion #4.

[0252] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 1.5g sodium dodecyl sulfate, 30g deionized water, 55.8g 3-methacryloyloxypropyltrimethoxysilane, 1.2g 3-methacryloyloxypropylmethyldimethoxysilane, and 3g divinylbenzene. In a reactor, 210g of deionized water was added, the temperature was raised to 70℃, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78℃ for 1 hour of maturation to obtain the silicon-containing organic resin particle emulsion #5.

[0253] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 3g sodium dodecyl sulfate, 30g deionized water, 54g 3-methacryloyloxypropyltrimethoxysilane, 3g 3-methacryloyloxypropylmethyldimethoxysilane, and 3g divinylbenzene. In a reactor, 210g of deionized water was added, the temperature was raised to 70℃, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78℃ for 1 hour of maturation to obtain the silicone-containing organic resin particle emulsion #6.

[0254] A pre-emulsion was prepared by emulsifying 0.3g sodium persulfate, 0.3g sodium bicarbonate, 6g sodium dodecyl sulfate, 30g deionized water, 54g 3-methacryloyloxypropyltrimethoxysilane, 3g 3-methacryloyloxypropylmethyldimethoxysilane, and 3g divinylbenzene. In a reactor, 210g of deionized water was added, the temperature was raised to 70°C, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78°C and the reaction was allowed to mature for 1 hour to obtain the 7# emulsion containing silicon-containing organic resin particles.

[0255] 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 3-methacryloyloxypropyltrimethoxysilane. In a reactor, 210g of deionized water was added, the temperature was raised to 70℃, and the pre-emulsion was added dropwise under nitrogen protection and stirring. After reacting for 4 hours, the temperature was raised to 78℃ for 1 hour of maturation to obtain the silicon-containing organic resin particle D1# emulsion.

[0256] Performance testing of silicone-containing organic resin particles

[0257] (1) Glass transition temperature T of silicon-containing organic resin particles g test

[0258] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. Determine whether the silicon-containing organic resin particles have a glass transition temperature T below 300℃ using the DSC curve. g .

[0259] (2) Melting point test of silicon-containing organic resin particles

[0260] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. Determine whether the silicon-containing organic resin particles have a melting point using the DSC curve.

[0261] (3) Particle size test

[0262] Dv10, Dv50, and Dv90 represent the particle sizes corresponding to a cumulative volumetric distribution percentage of 10%, 50%, and 90%, respectively. The testing standard is based on GB / T 19077-2016. The testing instrument is a MasterSizer 3000 laser particle size analyzer. During testing, 1g of the sample to be tested is added to a clean small beaker, followed by 20ml of deionized water. The sample is sonicated at 53kHz / 120W for 5 minutes to ensure complete dispersion. The laser particle size analyzer is then turned on, and after cleaning the optical path system, the background is automatically measured. The sonicated solution is stirred to ensure uniform dispersion, then placed into the sample cell as required, and particle size measurement begins.

[0263] The silicon-containing organic resin particles 1# to 7# prepared above meet the following characteristics:

[0264] Silicon-containing organic resin particles have a network structure with carbon-carbon bonds as the main chain and silicon-oxygen and benzene ring structures in the side chains. They have no melting point and no glass transition temperature T below 300℃. g .

[0265] Next, the silicon-containing organic resin particles prepared above were used in the separator to verify their impact on the performance of the separator and the secondary battery cells.

[0266] The manufacturing process of a secondary battery cell is as follows.

[0267] A commercially available 7μm thick polyethylene microporous membrane was used as the porous base membrane. The prepared silica-containing organic resin particle emulsion, dispersant sodium carboxymethyl cellulose, and binder polyacrylate were mixed evenly in deionized water at a solid mass ratio of 90:2:8 to obtain a coating slurry. The coating slurry was then applied at a concentration of 2.3 g / m³. 2 The loading amount is uniformly coated on both surfaces of the porous base membrane, and the solvent is removed by drying to obtain the isolation membrane.

[0268] Lithium iron phosphate, a positive electrode active material, polyvinylidene fluoride (PVDF), a positive electrode binder, and carbon black, a positive electrode conductive agent, are added to N-methylpyrrolidone (NMP) at a mass ratio of 97:2:1. The mixture is stirred and mixed thoroughly to prepare a positive electrode slurry. The positive electrode slurry is then uniformly coated onto aluminum foil, a positive electrode current collector, and subsequently dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0269] 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 96.0:1.4:1.5:1.1 and thoroughly mixed to prepare a cathode slurry. 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.

[0270] At 25°C, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7 to obtain a mixed solvent. LiPF6 and vinylene carbonate (VC) 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 3%, based on the mass of the electrolyte.

[0271] The positive electrode, separator, and negative electrode are stacked, wound, and hot-pressed in sequence to obtain an electrode assembly. The electrode assembly is placed in a hard outer packaging, and the electrolyte prepared above is added. After processes such as encapsulation, standing, formation, and aging, a secondary battery cell is obtained.

[0272] Performance testing

[0273] (1) Peel force test between coating and porous base film

[0274] Cut the release liner into three 2.5cm x 15cm strips. Attach the strips to a test steel plate. Use 2cm wide test tape to adhere to the side of the release liner to be tested. Using a tensile testing machine, clamp the steel plate on one side and the tape on the other, perform a 180° peel test. Take the average peel force of the three strips as the peel force between the coating and the porous base film. The tensile rate is 50mm / min.

[0275] (2) Air permeability test of the separator membrane

[0276] The air permeability test of the separator membrane can be referenced in GB / T 36363-2018.

[0277] Cut the separator membrane into 5cm squares. Using a breathability meter, apply a pressure of 1.21kPa and test the permeability of 100ml of air, finding it to be 6.45cm. 2 The time required for the sealing membrane to open is taken as the membrane's air permeability value, expressed in seconds per 100 ml. The average of three parallel samples is taken as the test result. The higher the air permeability value of the sealing membrane, the worse its air permeability.

[0278] (3) Thermal shrinkage rate test of the separator film

[0279] The heat shrinkage rate test of the release liner can be referenced in GB / T 36363-2018.

[0280] 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.

[0281] 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.

[0282] 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.

[0283] (4) Cycle performance test of secondary battery cells

[0284] At 25℃, a single secondary battery cell is charged to 3.8V with a constant current of 1 / 3C, then charged to a current of 0.05C with a constant voltage of 3.8V, rested for 5 minutes, and then discharged to 2V with a constant current of 1 / 3C. The resulting discharge capacity is recorded as the initial capacity C0. The above charging and discharging steps are repeated, and the discharge capacity Cn of the single secondary battery cell after the nth cycle is recorded. The capacity retention rate of the single secondary battery cell after each cycle is Pn = (Cn / C0) × 100%. The capacity retention rate of the single secondary battery cell after 500 cycles can be used to reflect the difference in cycle performance of the single secondary battery cell.

[0285] Table 1

[0286] The test results above show that silicon-containing organic resin particles that simultaneously meet the requirements of a volume distribution particle size Dv50 of 80nm-320nm and a particle size distribution (Dv90-Dv10) / Dv50 of less than or equal to 1.7 can give the separator high bonding strength, good air permeability and good heat resistance, and enable the secondary battery cell to have good cycle performance.

[0287] 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. An isolation membrane comprising a porous base membrane and a coating on at least one side of the porous base membrane, wherein, The coating comprises silicon-containing organic resin particles, the volume distribution particle size Dv50 of the silicon-containing organic resin particles is 80-320 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is less than or equal to 1.

7.

2. The separator film according to claim 1, wherein The particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is 0.2-0.

7.

3. The separator film according to claim 1 or 2, wherein The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 85-260 nm.

4. The separator film according to any one of claims 1-3, wherein, The volume distribution particle size Dv10 of the silicon-containing organic resin particles is 50-120 nm; and / or, The volume distribution particle size Dv90 of the silicon-containing organic resin particles is 130-500 nm.

5. The separator film according to any one of claims 1 to 4, wherein The silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles.

6. The separator film according to any one of claims 1 to 5, wherein The silicon-containing organic resin particles contain benzene ring structures.

7. The separator film according to any one of claims 1 to 6, wherein The silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles are network structures formed with carbon-carbon bonds as the main chain, and the side chains contain benzene ring structures and siloxane structures.

8. The separator film according to any one of claims 1 to 7, wherein The silicon-containing organic resin particles comprise Si, O, C, and H elements.

9. The separator film according to claim 8, wherein, The mass fraction of Si elements in the silicon-containing organic resin particles is 10%-25%; and / or, The mass fraction of O elements in the silicon-containing organic resin particles is 10%-30%; and / or, The mass fraction of C elements in the silicon-containing organic resin particles is 50%-62%; and / or, The mass fraction of H elements in the silicon-containing organic resin particles is 5%-10%.

10. The separator membrane according to any one of claims 5 to 9, wherein, The silicon-containing organic crosslinked resin particles comprise crosslinking structure units, and the crosslinking structure units comprise divinylbenzene structure units, Optionally, the crosslinking structure units further comprise one or more of divinyl glycol diethenyl ether structure units, triethylene glycol diethenyl ether structure units, maleic acid diallyl ester structure units, ethylene glycol dimethyl acrylate structure units, 1,4-butanediol diacrylate structure units, 1,6-hexanediol diacrylate structure units, 1,8-octanediol diacrylate structure units, trimethylolpropane triacrylate structure units, pentaerythritol trimethacrylate structure units, tetraethylene glycol dimethacrylate structure units, tripropylene glycol diacrylate structure units, 2,2,4-trimethyl hexanedioyl di[2-ethylaziridine] structure units, 1,1-nonanedioyl di[2-methylaziridine] structure units, 1,1-(1,3-phenylene dicarbonyl) di[2-methylaziridine] structure units, trimethylolpropane tri(2-methyl-1-aziridinyl propionate) structure units, trimethylolpropane-tris[3-(2-methylaziridinyl) propionate] structure units, pentaerythritol tri(3-aziridinyl) propionate structure units.

11. The separator film according to any one of claims 1-10, wherein, The silicon-containing organic resin particles have no glass transition temperature below 300°C; and / or, The silicon-containing organic resin particles have no melting point; and / or, The true density of the silicon-containing organic resin particles is 1.2 g / cm 3 -1.5 g / cm 3 .

12. The separator film according to any one of claims 1 to 11, wherein, a mass content of the silicon-containing organic resin particles in the coating layer is 50% to 99% based on the total mass of the coating layer; and / or, a thickness of the coating layer is 0.5 μm to 5 μm; and / or, The areal density of the coating is 0.5 g / m 2 - 5 g / m 2 .

13. The separator membrane according to any one of claims 1 to 12, wherein, a ratio of a volume distribution particle size Dv50 of the silicon-containing organic resin particles to an average pore diameter of the porous base film is greater than or equal to 1.

1.

14. The separator membrane according to any one of claims 1 to 13, wherein, The separator film satisfies at least one of the following conditions (1) to (4): (1) the separator film has a longitudinal heat shrinkage of less than or equal to 1.75% when heated at 130°C for 1 hour; (2) the separator film has a transverse heat shrinkage of less than or equal to 1.75% when heated at 130°C for 1 hour; (3) the separator film has an air permeability of 170 s / 100 ml to 230 s / 100 ml; (4) a peeling force between the coating layer and the porous base film is greater than or equal to 28 N / m.

15. A silicon-containing organic resin particle, wherein, The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 80 nm to 320 nm, and a particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is less than or equal to 1.

7.

16. The silicon-containing organic resin particles according to claim 15, wherein, The particle size distribution (Dv90-Dv10) / Dv50 of the silicon-containing organic resin particles is 0.2 to 0.

7.

17. The silicon-containing organic resin particles according to claim 15 or 16, wherein, The volume distribution particle size Dv50 of the silicon-containing organic resin particles is 85 nm to 260 nm.

18. The silicon-containing organic resin particles according to any one of claims 15 to 17, wherein, the volume distribution particle size Dv10 of the silicon-containing organic resin particles is 50 nm to 120 nm; and / or, the volume distribution particle size Dv90 of the silicon-containing organic resin particles is 130 nm to 500 nm.

19. The silicon-containing organic resin particles according to any one of claims 15-18, wherein, The silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles.

20. The silicon-containing organic resin particles according to any one of claims 15-19, wherein, The silicon-containing organic resin particles contain a benzene ring structure.

21. The silicon-containing organic resin particles according to any one of claims 15-20, wherein, The silicon-containing organic resin particles are silicon-containing organic crosslinked resin particles, and the silicon-containing organic resin particles are network structures formed with carbon-carbon bonds as a main chain, and side chains containing a benzene ring structure and a siloxane structure.

22. The silicon-containing organic resin particles according to any one of claims 15-21, wherein, The silicon-containing organic resin particles include Si, O, C, and H elements.

23. The silicon-containing organic resin particles according to claim 22, wherein, a mass fraction of Si elements in the silicon-containing organic resin particles is 10% to 25%; and / or, a mass fraction of O elements in the silicon-containing organic resin particles is 10% to 30%; and / or, a mass fraction of C elements in the silicon-containing organic resin particles is 50% to 62%; and / or, a mass fraction of H elements in the silicon-containing organic resin particles is 5% to 10%.

24. The silicon-containing organic resin particles according to any one of claims 19-23, wherein, The silicon-containing organic crosslinked resin particles include a crosslinked structure unit, and the crosslinked structure unit includes a divinylbenzene structure unit, Optionally, the crosslinking structural unit further comprises one or more of a diethylene glycol divinyl ether structural unit, a triethylene glycol divinyl ether structural unit, a maleic acid diallyl ester structural unit, a ethylene glycol dimethacrylate structural unit, a 1,4-butanediol diacrylate structural unit, a 1,6-hexanediol diacrylate structural unit, a 1,8-octanediol diacrylate structural unit, a trimethylolpropane triacrylate structural unit, a pentaerythritol trimethacrylate structural unit, a tetraethylene glycol dimethacrylate structural unit, a tripropylene glycol diacrylate structural unit, a 2,2,4-trimethylhexanedioic acid bis[2-ethylaziridine] structural unit, a 1,1-nonanedioic acid bis[2-methylaziridine] structural unit, a 1,1-(1,3-phenylenedicarbonyl)bis[2-methylaziridine] structural unit, a trimethylolpropane tris(2-methyl-1-aziridinylpropionate) structural unit, a trimethylolpropane-tris[3-(2-methylaziridinyl)propionate] structural unit, a pentaerythritol tris(3-aziridinyl)propionate structural unit.

25. The silicon-containing organic resin particles according to any one of claims 15 to 24, wherein, the silicon-containing organic resin particles have no glass transition temperature below 300°C; and / or, the silicon-containing organic resin particles have no melting point; and / or, The true density of the silicon-containing organic resin particles is 1.2 g / cm 3 -1.5 g / cm 3 .

26. A method for producing silicon-containing organic resin particles, comprising the steps of: A pre-emulsion containing a monomer represented by Formula I, an additive represented by Formula II, a crosslinking agent, an emulsifier, an initiator, and water is provided, and an emulsion polymerization reaction is performed under heating, inert gas protection, and stirring conditions to obtain silicon-containing organic resin particles, R1, R2, R3are each independently selected from C1-C4 alkyl, C2-C4 alkenyl, C3-C12 trialkylsilyl groups, and R4is selected from C2 to C8 alkenyl or C4 to C8 (meth)acryloxyalkyl groups; one or two of R5, R6, R7are each independently selected from H, C1-C4 alkyl, C2-C4 alkenyl, C3-C12 trialkylsilyl groups, and the remaining is selected from C1-C8 alkoxy groups, and R8is selected from C2 to C8 alkenyl or C4 to C8 (meth)acryloxyalkyl groups; the mass fraction of the additive of Formula II is 2% to 13.5% based on 100% of the total mass of the monomer of Formula I, the additive of Formula II, and the crosslinking agent.

27. The method according to claim 26, wherein, the monomer of Formula I comprises one or more of γ-methacryloyloxypropyl tris(trimethylsiloxy)silane, (3-acryloyloxypropyl)tris(trimethylsiloxy)silane, 3-methacryloyloxypropyltrimethoxysilane, acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, acryloyloxypropyltriethoxysilane, γ-methacryloyloxypropyltriisopropoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-methacryloyloxypropyltris(methoxyethoxy)silane, vinyltrimethoxysilane, 7-octenyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, tri-t-butoxyvinylsilane, vinyltris(β-methoxyethoxy)silane, ethylene tris[(1-methylethenyl)oxy]silane, vinyltris-t-butylperoxysilane; and / or, The additive shown in formula II includes one or more of 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldimethoxysilane, methacryloxypropyldimethylmethoxysilane, (3-acryloxy)dimethylmethoxysilane, 3-methacryloxypropyldimethylethoxysilane, diethylmethylvinylsilane, vinyl dimethyl ethoxysilane, methyl vinyl dimethoxy silane, vinyl methyl dimethoxy silane, vinyl methyl diethoxy silane, methyl vinyl dimethoxy silane, 3-(methacryloxy)propylmethyldiethoxysilane.

28. The method of claim 26 or 27, wherein, The emulsifier includes one or more of alkyl sulfate, alkyl sulfonate, Tween emulsifier, fatty alcohol polyoxyethylene ether, fatty alcohol polyoxypropylene ether, cetyl stearyl alcohol polyether, oleyl alcohol polyether; and / or, The mass fraction of the emulsifier is 0.5%-10% based on the total mass of the monomer shown in formula I, the additive shown in formula II, and the crosslinking agent being 100%.

29. The method of any one of claims 26-28, wherein, 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, tripropyleneglycol diacrylate, 2,2,4-trimethyladipylbis[2-ethylaziridine], 1,1-nonanedioylbis[2-methylaziridine], 1,1-(1,3-phenylenedicarbonyl)bis[2-methylaziridine], trimethylolpropane tris(2-methyl-1-aziridinylpropionate), trimethylolpropane-tris[3-(2-methylaziridinyl)propionate], pentaerythritol tris(3-aziridinyl)propionate; and / or, The mass fraction of the crosslinking agent is 3%-18% based on the total mass of the monomer shown in formula I, the additive shown in formula II, and the crosslinking agent being 100%.

30. The method of any one of claims 26-29, wherein, The heating temperature of the maturation stage of the emulsion polymerization reaction is 75°C-92°C; and / or, the heating time of the maturation stage of the emulsion polymerization reaction is 1h-5h.

31. The method of any one of claims 26-30, wherein, The emulsion polymerization reaction includes the following steps: under the conditions of a first heating temperature, inert gas protection, and stirring, the pre-emulsion is added dropwise into a reactor containing water, and after a first time, the temperature is raised to the heating temperature of the maturation stage for maturation reaction to obtain the silicon-containing organic resin particles, Optionally, the first heating temperature is 55°C-70°C; Optionally, the first time is 3h-6h.

32. A silicon-containing organic resin particle emulsion, comprising the silicon-containing organic resin particles of any one of claims 15-25, or obtained by the method of any one of claims 26-31.

33. A secondary battery cell comprising a positive electrode sheet, a negative electrode sheet, and the separator film according to any one of claims 1 to 14, the separator film being disposed between the positive electrode sheet and the negative electrode sheet.

34. A battery device comprising a plurality of the secondary battery cell according to claim 33.

35. An electric device comprising the secondary battery cell according to claim 33 or the battery device according to claim 34.

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