Organic polymer particle and preparation method therefor, separator, secondary battery cell, battery device, and electric device

Abstract

An organic polymer particle and a preparation method therefor, 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 organic polymer particles, the organic polymer particles contain triazine ring structural units, and a differential scanning calorimetry curve of the organic polymer particles has no endothermic melting peaks at 300°C or lower. The secondary battery cell has both high reliability and a high mass energy density.

Description

Organic polymer particles and their preparation methods, 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. 202410946481.9, filed on July 15, 2024, entitled “Organic polymer particles and preparation method thereof, separator membrane, battery cell, and electrical device”, and Chinese Patent Application No. 202411388004.1, filed on September 30, 2024, entitled “Organic polymer particles and preparation method thereof, 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 an organic polymer particle and its preparation method, 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 an organic polymer particle and its preparation method, a separator, a secondary battery cell, a battery device, and an electrical device. The secondary battery cell has both high reliability and high energy density.

[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 organic polymer particles containing triazine ring structural units, and the differential scanning calorimetry curve of the organic polymer particles having no melting endothermic peak below 300°C.

[0007] Organic polymer particles have low density, allowing secondary battery cells to achieve higher mass energy density. The organic polymer particles disclosed herein contain triazine ring structural units. The high rigidity of the triazine ring structure contributes to the good heat resistance of the organic polymer particles. Furthermore, the differential scanning calorimetry (DSC) curve of the organic polymer particles shows no melting endothermic peak below 300°C, indicating that the organic polymer particles have no melting point and are stable within this temperature range. By using organic polymer particles containing triazine ring structural units and exhibiting no melting endothermic peak below 300°C in a separator membrane, the organic polymer particles can generate forces that resist separator shrinkage, thereby improving the overall thermal shrinkage of the separator membrane, enhancing its heat resistance, and increasing the reliability of the secondary battery cell. Therefore, the separator membrane disclosed herein enables secondary battery cells to possess both high reliability and high mass energy density.

[0008] In some embodiments, the organic polymer particles include bridging structures that connect the triazine ring structural units.

[0009] In some embodiments, the bridging structure includes one or more combinations of alkylene, alkylene ether, alkylene amine, ester, and amide groups.

[0010] In some embodiments, the triazine ring structural unit further has substituents, which include one or more combinations of alkyl, alkenyl, phenyl, cycloalkyl, amino, hydroxyl, and halogen.

[0011] In some embodiments, the organic polymer particles include at least one of the following: melamine aldehyde polymers and their derivatives, etherified melamine aldehyde polymers and their derivatives, etherified melamine aldehyde-polyol polymers and their derivatives, etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives, and etherified melamine aldehyde-polyamine amide polymers and their derivatives.

[0012] In some embodiments, the melamine-formaldehyde polymers and their derivatives include one or more of melamine-formaldehyde, benzyl melamine-formaldehyde, melamine-benzene melamine-formaldehyde, melamine-(2,4-diamino-1,3,5-triazine)formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine)formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine)formaldehyde, trihydrazine-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine)formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine)formaldehyde.

[0013] In some embodiments, the etherified melamine aldehyde polymers and their derivatives include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzyl melamine formaldehyde, and butyl etherified benzyl melamine formaldehyde.

[0014] In some embodiments, the etherified melamine-formaldehyde-polyol polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-ethylene glycol polymer, methyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, methyl etherified melamine-formaldehyde-1,4-butanediol polymer, methyl etherified melamine-formaldehyde-polyester polyol polymer, methyl etherified melamine-formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine-formaldehyde-ethylene glycol polymer, butyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, butyl etherified melamine-formaldehyde-1,4-butanediol polymer, and butyl etherified melamine-formaldehyde-polyester polyol polymer.

[0015] In some embodiments, the etherified melamine-formaldehyde-polycarboxylic acid polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-oxalic acid polymer, methyl etherified melamine-formaldehyde-malonic acid polymer, methyl etherified melamine-formaldehyde-succinic acid polymer, methyl etherified melamine-formaldehyde-citric acid polymer, methyl etherified melamine-formaldehyde-phthalic acid polymer, butyl etherified melamine-formaldehyde-oxalic acid polymer, butyl etherified melamine-formaldehyde-malonic acid polymer, butyl etherified melamine-formaldehyde-citric acid polymer, butyl etherified melamine-formaldehyde-terephthalic acid polymer, and butyl etherified melamine-formaldehyde-phthalic acid polymer.

[0016] In some embodiments, the etherified melamine-formaldehyde-polyamine amide polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-glyoxalamide polymer, methyl etherified melamine-formaldehyde-malonamide polymer, methyl etherified melamine-formaldehyde-isophthalimide polymer, and butyl etherified melamine-formaldehyde-glyoxalamide polymer.

[0017] In some embodiments, the organic polymer particles are thermosetting resins.

[0018] In some embodiments, the organic polymer particles are amorphous polymers.

[0019] In some embodiments, the organic polymer particles have no glass transition temperature below 300°C.

[0020] The organic polymer 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.

[0021] In some embodiments, the initial thermogravimetric temperature T of the organic polymer particles 3d The temperature ranges from 296℃ to 340℃.

[0022] The initial thermogravimetric temperature T of organic polymer particles 3d The high value indicates good thermal stability, which can better resist the thermal shrinkage of the separator, improve the heat resistance of the separator, and enhance the reliability of the secondary battery cells.

[0023] In some embodiments, the volume distribution particle size Dv50 of the organic polymer particles is 200nm-820nm.

[0024] In some embodiments, the true density of the organic polymer particles is 1.1 g / cm³. 3 -1.7g / cm 3 This allows secondary battery cells using the separator membrane disclosed herein to have a higher mass energy density.

[0025] In some embodiments, the organic polymer particles in the coating contain 50%-99% by mass, based on the total mass of the coating.

[0026] In some embodiments, the thickness of the coating is 0.5 μm-5 μm.

[0027] In some embodiments, the areal density of the coating is 0.45 g / m³. 2 -4.5g / m 2 .

[0028] In some embodiments, the ratio of the volume distribution particle size Dv50 of the organic polymer particles to the average pore size of the porous base membrane is greater than or equal to 2.5.

[0029] 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 2.2%.

[0030] 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 2.0%.

[0031] In some embodiments, the air permeability of the isolation membrane is 170s / 100ml-225s / 100ml.

[0032] In some embodiments, the longitudinal tensile strength of the separator is greater than or equal to 2100 kg / cm². 2 .

[0033] In some embodiments, the transverse tensile strength of the separator is greater than or equal to 1800 kg / cm². 2 .

[0034] In some embodiments, the puncture strength of the isolation membrane is greater than or equal to 405 kgf.

[0035] Secondly, this disclosure provides an organic polymer particle containing a triazine ring structural unit, and the differential scanning calorimetry curve of the organic polymer particle has no melting endothermic peak below 300°C.

[0036] In some embodiments, the organic polymer particles include bridging structures that connect the triazine ring structural units.

[0037] In some embodiments, the bridging structure includes one or more combinations of alkylene, alkylene ether, alkylene amine, ester, and amide groups.

[0038] In some embodiments, the triazine ring structural unit further has substituents, which include one or more combinations of alkyl, alkenyl, phenyl, cycloalkyl, amino, hydroxyl, and halogen.

[0039] In some embodiments, the organic polymer particles include at least one of the following: melamine aldehyde polymers and their derivatives, etherified melamine aldehyde polymers and their derivatives, etherified melamine aldehyde-polyol polymers and their derivatives, etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives, and etherified melamine aldehyde-polyamine amide polymers and their derivatives.

[0040] In some embodiments, the melamine-formaldehyde polymers and their derivatives include one or more of melamine-formaldehyde, benzyl melamine-formaldehyde, melamine-benzene melamine-formaldehyde, melamine-(2,4-diamino-1,3,5-triazine)formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine)formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine)formaldehyde, trihydrazine-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine)formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine)formaldehyde.

[0041] In some embodiments, the etherified melamine aldehyde polymers and their derivatives include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzyl melamine formaldehyde, and butyl etherified benzyl melamine formaldehyde.

[0042] In some embodiments, the etherified melamine-formaldehyde-polyol polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-ethylene glycol polymer, methyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, methyl etherified melamine-formaldehyde-1,4-butanediol polymer, methyl etherified melamine-formaldehyde-polyester polyol polymer, methyl etherified melamine-formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine-formaldehyde-ethylene glycol polymer, butyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, butyl etherified melamine-formaldehyde-1,4-butanediol polymer, and butyl etherified melamine-formaldehyde-polyester polyol polymer.

[0043] In some embodiments, the etherified melamine-formaldehyde-polycarboxylic acid polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-oxalic acid polymer, methyl etherified melamine-formaldehyde-malonic acid polymer, methyl etherified melamine-formaldehyde-succinic acid polymer, methyl etherified melamine-formaldehyde-citric acid polymer, methyl etherified melamine-formaldehyde-phthalic acid polymer, butyl etherified melamine-formaldehyde-oxalic acid polymer, butyl etherified melamine-formaldehyde-malonic acid polymer, butyl etherified melamine-formaldehyde-citric acid polymer, butyl etherified melamine-formaldehyde-terephthalic acid polymer, and butyl etherified melamine-formaldehyde-phthalic acid polymer.

[0044] In some embodiments, the etherified melamine-formaldehyde-polyamine amide polymer and its derivatives include one or more of the following: methyl etherified melamine-formaldehyde-glyoxalamide polymer, methyl etherified melamine-formaldehyde-malonamide polymer, methyl etherified melamine-formaldehyde-isophthalimide polymer, and butyl etherified melamine-formaldehyde-glyoxalamide polymer.

[0045] In some embodiments, the organic polymer particles are thermosetting resins.

[0046] In some embodiments, the organic polymer particles are amorphous polymers.

[0047] In some embodiments, the organic polymer particles have no glass transition temperature below 300°C.

[0048] In some embodiments, the initial thermogravimetric temperature T of the organic polymer particles 3d The temperature ranges from 296℃ to 340℃.

[0049] In some embodiments, the volume distribution particle size Dv50 of the organic polymer particles is 200nm-820nm.

[0050] In some embodiments, the true density of the organic polymer particles is 1.1 g / cm³. 3 -1.7g / cm3 .

[0051] Thirdly, this disclosure provides a method for preparing organic polymer particles, comprising the following steps: providing a precursor containing a triazine ring structure; heating and curing the precursor containing the triazine ring structure in an oxygen-containing atmosphere, followed by crushing, to obtain organic polymer particles containing triazine ring structural units, wherein the heating and curing temperature is 180℃-280℃.

[0052] In some embodiments, the heating and curing time is 1-6 hours.

[0053] In some embodiments, the precursor containing the triazine ring structure includes at least one of the following: melamine aldehyde resin, etherified melamine aldehyde resin, or a mixture of etherified melamine aldehyde resin and at least one of polyol, polycarboxylic acid, or polyamide.

[0054] In some embodiments, the precursor containing the triazine ring structure comprises a melamine aldehyde resin, which is obtained by reacting an aldehyde compound with an amine-substituted triazine compound, wherein the amine-substituted triazine compound comprises melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound is 1.7:1 to 3:1.

[0055] In some embodiments, the precursor containing the triazine ring structure comprises an etherified melamine aldehyde resin, which is obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound, wherein the amine-substituted triazine compound comprises melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound is 4:1 to 7:1.

[0056] In some embodiments, the amine-substituted triazine compound includes one or more compounds of the following general formula, wherein R1 and R2 are each independently selected from H, -NH2, and C1-C8 alkyl, R3 is selected from H, -NH2, -NHR4, C1-C8 alkyl, C2-C8 alkenyl, phenyl, C7-C12 alkylphenyl, C7-C12 phenylalkyl, and C5-C8 cycloalkyl, and R4 is selected from -NH2 and C1-C8 alkyl.

[0057] In some embodiments, the aldehyde compounds include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0058] In some embodiments, the alcohol compound includes one or more of methanol, ethanol, and butanol.

[0059] In some embodiments, the amine-substituted triazine compound includes melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 6-ethyl-1,3,5-triazine-2,4-diamine, 6-isopropyl-1,3,5-triazine-2,4-diamine, 6-pentyl-2,4-diamino-1,3,5-triazine, and 6-heptyl-2,4-diamino-triazine. One or more of the following: 2-vinyl-4,6-diamino-1,3,5-triazine, 2,4-diamino-6-(4-methylphenyl)-1,3,5-triazine, 6-cyclohexyl-1,3,5-triazine-2,4-diamine, 6-(3-methylphenyl)-1,3,5-triazine-2,4-diamine, 6-o-tolyl-1,3,5-triazine-2,4-diamine, 6-(2,4-dimethylphenyl)-1,3,5-triazine-2,4-diamine, 6-phenylmethyl-1,3,5-triazine-2,4-diamine, (diamino-1,3,5-triazine-2-yl)methanol, and 2-chloro-4,6-diamino-1,3,5-triazine.

[0060] In some embodiments, the etherified melamine-formaldehyde resin includes one or more of methyl etherified melamine-formaldehyde resin, butyl etherified melamine-formaldehyde resin, methyl etherified benzyl melamine-formaldehyde resin, and butyl etherified benzyl melamine-formaldehyde resin.

[0061] In some embodiments, the polyol includes one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethylbutylpropanediol, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyol, and polyester polyol.

[0062] In some embodiments, the polycarboxylic acids include one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid.

[0063] In some embodiments, the polyamide includes one or more of ethylene glycol, malonamide, succinamide, adipamide, and isophthalimide.

[0064] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyol, wherein the molar ratio of the etherified melamine aldehyde resin to the polyol is 1:2 to 1:6.

[0065] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polycarboxylic acid, wherein the molar ratio of the etherified melamine aldehyde resin to the polycarboxylic acid is 1:2 to 1:6.

[0066] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyamide, wherein the molar ratio of the etherified melamine aldehyde resin to the polyamide is 1:2 to 1:6.

[0067] Fourthly, 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] Fifthly, this disclosure provides a battery device comprising a plurality of secondary battery cells according to the fourth aspect of this disclosure.

[0069] Sixthly, this disclosure provides an electrical device that includes a secondary battery cell according to the fourth aspect of this disclosure or a battery device according to the fifth 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 organic polymer particles, their preparation methods, 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 "organic polymer particles" in the coating of the separator membrane primarily serve to improve heat resistance and have virtually no adhesive properties.

[0098] The separator is a crucial component supporting the electrochemical processes of charging and discharging in a secondary battery cell. Commonly used separators are often made of polyolefins; however, polyolefins have poor heat resistance and are prone to softening or melting at high temperatures, which can lead to short circuits in the secondary battery cells. To improve the heat resistance of the separator, a coating is usually applied. Boehmite, alumina, and other inorganic particles are commonly used heat-resistant fillers; however, these fillers have high density and a large mass for the same bulk volume, thus affecting the energy density of the secondary battery cells.

[0099] Based on this, embodiments of the present disclosure provide an organic polymer particle that, when used in a separator membrane, enables secondary battery cells to possess both high reliability and high-quality energy density.

[0100] The organic polymer particles disclosed herein contain triazine ring structural units, and the differential scanning calorimetry curve of the organic polymer particles has no melting endothermic peak below 300°C.

[0101] Organic polymer particles have low density, allowing secondary battery cells to achieve higher mass energy density. The organic polymer particles disclosed herein contain triazine ring structural units. The high rigidity of the triazine ring structure contributes to the good heat resistance of the organic polymer particles. Furthermore, the differential scanning calorimetry (DSC) curve of the organic polymer particles of this disclosure shows no melting endothermic peak below 300°C, indicating that the organic polymer particles have no melting point and are stable within this temperature range. By using organic polymer particles containing triazine ring structural units and showing no melting endothermic peak below 300°C in a separator membrane, the organic polymer particles can generate a force that resists the shrinkage of the separator membrane, thereby improving the overall thermal shrinkage of the separator membrane, enhancing its heat resistance, and improving the reliability of the secondary battery cell. Therefore, the use of the organic polymer particles of this disclosure in a separator membrane enables secondary battery cells to possess both high reliability and high mass energy density.

[0102] Differential scanning calorimetry (DSC) curves of organic polymer particles can be tested as follows: Take an appropriate amount of sample (e.g., 5 mg-15 mg) and place it in the crucible of the differential scanning calorimeter (DSC), level it, and cover the crucible with the lid; Parameter settings: nitrogen atmosphere, purge gas 60 mL / min, protective gas 20 mL / min; Program settings: heat from 25 °C to 200 °C at a heating rate of 10 °C / min, hold for 5 min to eliminate thermal history, then cool from 200 °C to -40 °C at a cooling rate of 10 °C / min, and then heat to 300 °C at a heating rate of 10 °C / min to obtain the differential scanning calorimetry curve, i.e., the DSC curve.

[0103] The organic polymer particles disclosed herein also include bridging structures that connect the triazine ring structural units.

[0104] Organic polymer particles contain multiple triazine ring structural units in their molecular structure. The bridging structure refers to the groups that connect the triazine ring structural units, and the bridging structures may be the same or different.

[0105] In some embodiments, the bridging structure may include one or more of alkylene groups, alkylene ethers, alkylene amines, ester groups, and amide groups.

[0106] Optionally, the bridging structure may include one or more of methylene, methylene ether, and methyleneamine.

[0107] In some embodiments, the triazine ring structural unit may also have substituents, which may include one or more combinations of alkyl, alkenyl, phenyl, cycloalkyl, amino, hydroxyl, and halogen.

[0108] In some embodiments, the organic polymer particles may include at least one of the following: melamine aldehyde polymers and their derivatives, etherified melamine aldehyde polymers and their derivatives, etherified melamine aldehyde-polyol polymers and their derivatives, etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives, and etherified melamine aldehyde-polyamine amide polymers and their derivatives.

[0109] In some embodiments, melamine aldehyde polymers and their derivatives may include melamine formaldehyde polymers and their derivatives.

[0110] Optionally, melamine-formaldehyde polymers and their derivatives may include one or more of the following: melamine-formaldehyde, benzyl melamine-formaldehyde, melamine-benzene melamine-formaldehyde, melamine-(2,4-diamino-1,3,5-triazine)formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine)formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine)formaldehyde, trihydrazine-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine)formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine)formaldehyde.

[0111] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include etherified melamine formaldehyde polymers and their derivatives.

[0112] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include methyl etherified melamine aldehyde polymers and their derivatives, diethyl etherified melamine aldehyde polymers and their derivatives, butyl etherified melamine aldehyde polymers and their derivatives, and methyl-butyl mixed etherified melamine aldehyde polymers and their derivatives.

[0113] Optionally, the etherified melamine-formaldehyde polymers and their derivatives may include methyl etherified melamine-formaldehyde polymers and their derivatives, diethyl etherified melamine-formaldehyde polymers and their derivatives, butyl etherified melamine-formaldehyde polymers and their derivatives, and methyl-butyl mixed etherified melamine-formaldehyde polymers and their derivatives.

[0114] Etherified melamine aldehyde polymers and their derivatives may include one or more of partially etherified melamine aldehyde polymers and their derivatives, and fully etherified melamine aldehyde polymers and their derivatives. Optionally, etherified melamine aldehyde polymers and their derivatives may include fully etherified melamine aldehyde polymers and their derivatives.

[0115] In some embodiments, etherified melamine aldehyde polymers and their derivatives may include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzyl melamine formaldehyde, and butyl etherified benzyl melamine formaldehyde.

[0116] Etherified melamine aldehyde-polyol polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polyol. Optionally, the molar ratio of etherified melamine aldehyde resin to polyol can be 1:2 to 1:6.

[0117] In some embodiments, the polyol may include one or more of diols, triols, and tetraols. Optionally, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethylbutyric acid, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyols, and polyester polyols. More preferably, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, polyvinyl alcohol, and polyester polyols.

[0118] Optionally, the polyester polyol may include one or more of the following: polyethylene adipate diol, 1,4-butanediol adipate diol, propylene adipate diol, neopentyl adipate diol, neopentyl adipate-1,6-hexanediol adipate diol, hexanediol adipate diol, polycarbonate diol, and polycaprolactone diol.

[0119] Optionally, the polyether polyol may include one or more of polyoxypropylene glycol, polyoxypropylene triol, and polytetrahydrofuran glycol.

[0120] Optionally, the molecular weight of the polyester polyol can be below 5000, and optionally below 2000.

[0121] Optionally, the molecular weight of the polyether polyol can be below 5000, and optionally below 2000.

[0122] Optionally, the molecular weight of polyvinyl alcohol can be below 5000, and optionally below 2000.

[0123] In some embodiments, the etherified melamine-formaldehyde-polyol polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-ethylene glycol polymer, methyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, methyl etherified melamine-formaldehyde-1,4-butanediol polymer, methyl etherified melamine-formaldehyde-polyester polyol polymer, methyl etherified melamine-formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine-formaldehyde-ethylene glycol polymer, butyl etherified melamine-formaldehyde-1,2-propylene glycol polymer, butyl etherified melamine-formaldehyde-1,4-butanediol polymer, and butyl etherified melamine-formaldehyde-polyester polyol polymer.

[0124] Etherified melamine aldehyde-polycarboxylic acid polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polycarboxylic acid. Optionally, the molar ratio of etherified melamine aldehyde resin to polycarboxylic acid can be 1:2 to 1:6.

[0125] In some embodiments, the polycarboxylic acid may include one or more of dicarboxylic acids, tricarboxylic acids, and tetracarboxylic acids. Optionally, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid. More preferably, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, and terephthalic acid.

[0126] In some embodiments, the etherified melamine-formaldehyde-polycarboxylic acid polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-oxalic acid polymer, methyl etherified melamine-formaldehyde-malonic acid polymer, methyl etherified melamine-formaldehyde-succinic acid polymer, methyl etherified melamine-formaldehyde-citric acid polymer, methyl etherified melamine-formaldehyde-phthalic acid polymer, butyl etherified melamine-formaldehyde-oxalic acid polymer, butyl etherified melamine-formaldehyde-malonic acid polymer, butyl etherified melamine-formaldehyde-citric acid polymer, butyl etherified melamine-formaldehyde-terephthalic acid polymer, and butyl etherified melamine-formaldehyde-phthalic acid polymer.

[0127] Etherified melamine aldehyde-polyamine amide polymers and their derivatives refer to the products of high-temperature crosslinking and curing reaction between etherified melamine aldehyde resin and polyamine amide. Optionally, the molar ratio of etherified melamine aldehyde resin to polyamine amide can be 1:2 to 1:6.

[0128] In some embodiments, the polyamide may include one or more of ethylene glycol, malonamide, succinamide, adipamide, and isophthalimide. Optionally, the polyamide may include one or more of ethylene glycol, malonamide, and isophthalimide.

[0129] In some embodiments, the etherified melamine-formaldehyde-polyamine amide polymer and its derivatives may include one or more of the following: methyl etherified melamine-formaldehyde-glyoxalamide polymer, methyl etherified melamine-formaldehyde-malonamide polymer, methyl etherified melamine-formaldehyde-isophthalimide polymer, and butyl etherified melamine-formaldehyde-glyoxalamide polymer.

[0130] The organic polymer particles disclosed herein are thermosetting resins.

[0131] The organic polymer particles disclosed herein are amorphous polymers.

[0132] In some embodiments, the true density of the organic polymer particles can be 1.1 g / cm³. 3 -1.7g / cm 3 .

[0133] Currently, the true density of inorganic particles such as boehmite and alumina is typically 2.5 g / cm³. 3 -3.5g / cm 3 The organic polymer 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.

[0134] The organic polymer particles disclosed herein are poorly soluble in both water and organic solvents, such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), and chloroform, at 25°C. They are also insoluble in the mobile phase used in gel permeation chromatography and the molecular weight of the organic polymer particles cannot be determined by gel permeation chromatography.

[0135] In some embodiments, the organic polymer particles have no glass transition temperature below 300°C.

[0136] The organic polymer 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.

[0137] 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 organic polymer particles have a glass transition temperature T below 300℃. g .

[0138] 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.

[0139] Organic polymer particles have no glass transition temperature T below 300°C. g This means that the DSC curve of organic polymer particles does not show a step-like change in the range below 300℃.

[0140] In some embodiments, the initial thermogravimetric temperature T of the organic polymer particles 3d The temperature can range from 296℃ to 340℃. Optionally, the initial thermogravimetric temperature T of the organic polymer particles... 3d The temperature ranges are 300℃-340℃, 305℃-340℃, 310℃-340℃, 315℃-340℃, and 320℃-340℃.

[0141] Initial thermogravimetric temperature T 3d This refers to the temperature at which the mass of a thermogravimetric analysis test sample is reduced by 3% relative to its initial mass.

[0142] The initial thermogravimetric temperature T of organic polymer particles 3d The high value indicates good thermal stability, which can better resist the thermal shrinkage of the separator, improve the heat resistance of the separator, and enhance the reliability of the secondary battery cells.

[0143] The initial thermogravimetric temperature T of organic polymer particles 3d The test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the alumina crucible of the thermogravimetric analyzer (TGA), level it, and cover the crucible with the lid; Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; Temperature rise program: heating rate 10℃ / min, temperature range 35℃-600℃; Obtain the temperature corresponding to a 3% loss of sample mass relative to the initial mass (i.e., 97% of the initial mass) from the test curve, which is the initial thermogravimetric temperature T. 3d .

[0144] In some embodiments, the volume distribution particle size Dv50 of the organic polymer particles can be 200 nm-820 nm.

[0145] Dv50 represents the particle size corresponding to a cumulative volumetric distribution percentage of 50% for the material. It can be measured using a laser particle size analyzer, referring to GB / T 19077-2016. During testing, add 1g of the sample to a clean small beaker, along with 20ml of deionized water. Sonicate at 53kHz / 120W for 5 minutes to ensure complete dispersion. Turn on the laser particle size analyzer, clean the optical path system, and automatically test the background. Stir the sonicated solution to ensure uniform dispersion, then place it in the sample cell as required and begin measuring the particle size. A MasterSizer 3000 laser particle size analyzer can be used as the testing instrument.

[0146] This disclosure also provides a method for preparing organic polymer particles, which can prepare the above-mentioned organic polymer particles.

[0147] The method for preparing organic polymer particles includes the following steps: providing a precursor containing a triazine ring structure; heating and curing the precursor containing the triazine ring structure in an oxygen-containing atmosphere, followed by crushing, to obtain organic polymer particles containing triazine ring structural units. The heating and curing temperature is 180℃-280℃. After heating and curing, a bridging structure is formed between the triazine ring structural units in the precursor containing the triazine ring structure.

[0148] The preparation method provided in this embodiment yields organic polymer particles with good heat resistance.

[0149] The temperature for heat curing is 180℃-280℃, for example, it can be 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, 250℃, 255℃, 260℃, 265℃, 270℃, 275℃, 280℃, or any combination of the above values.

[0150] When the heating and curing temperature is within the above range, the precursor containing the triazine ring structure can be formed into organic polymer particles with good heat resistance.

[0151] Optionally, the heat curing temperature can be 190℃-280℃, 200℃-280℃, 210℃-280℃, 220℃-280℃, or 230℃-280℃.

[0152] In some embodiments, the heating curing time can be 1h-6h, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, or any range of the above values.

[0153] Heating and curing time within the above range is beneficial for the formation of organic polymer particles with better heat resistance from precursors containing triazine ring structures.

[0154] Optionally, the curing time can be 2-6 hours.

[0155] In some embodiments, the oxygen-containing atmosphere may include oxygen and an inert gas. Optionally, the inert gas may be one or more of nitrogen, argon, and helium, among others. In some embodiments, the volume fraction of oxygen in the oxygen-containing atmosphere may be 5%-50%. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere may be 10%-30%. More preferably, the oxygen-containing atmosphere may be an air atmosphere.

[0156] In some embodiments, the organic polymer particles containing triazine ring structural units further include sieving and demagnetizing steps after crushing.

[0157] In some embodiments, the precursor containing a triazine ring structure may include at least one of the following: melamine aldehyde resin, etherified melamine aldehyde resin, or a mixture of etherified melamine aldehyde resin and at least one of polyol, polycarboxylic acid, or polyamide.

[0158] In some embodiments, the precursor containing a triazine ring structure may include a melamine aldehyde resin, which may be obtained by reacting an aldehyde compound with an amine-substituted triazine compound, wherein the amine-substituted triazine compound may include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 1.7:1-3:1, for example, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1, or any range of the above ratios. More preferably, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 2.1:1-3:1, 2.2:1-3:1, 2.3:1-3:1, 2.4:1-3:1, or 2.5:1-3:1.

[0159] In some embodiments, the precursor containing a triazine ring structure may include an etherified melamine aldehyde resin, which may be obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound. The amine-substituted triazine compound may include melamine and / or melamine derivatives. Optionally, the molar ratio of the aldehyde compound to the amine-substituted triazine compound may be 4:1 to 7:1, for example, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, 5:1, 5.2:1, 5.4:1, 5.6:1, 5.8:1, 6:1, 6.2:1, 6.4:1, 6.6:1, 6.8:1, 7:1, or any range of the above ratios. Alternatively, the molar ratio of the aldehyde compound to the amine-substituted triazine compound can be 5:1-7:1, 5.4:1-7:1, 5.8:1-7:1, or 6.2:1-7:1.

[0160] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyol, wherein the molar ratio of the etherified melamine aldehyde resin to the polyol may be 1:2 to 1:6.

[0161] In some embodiments, the precursor containing a triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polycarboxylic acid, wherein the molar ratio of the etherified melamine aldehyde resin to the polycarboxylic acid can be 1:2 to 1:6.

[0162] In some embodiments, the precursor containing the triazine ring structure comprises a mixture of etherified melamine aldehyde resin and polyamide, wherein the molar ratio of the etherified melamine aldehyde resin to the polyamide may be 1:2 to 1:6.

[0163] In some embodiments, the alcohol compound that forms the etherified melamine aldehyde resin may include one or more of methanol, ethanol, and butanol.

[0164] In some embodiments, the aldehyde compounds forming melamine aldehyde resins and etherified melamine aldehyde resins may include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0165] In some embodiments, the amine-substituted triazine compound forming melamine-formaldehyde resins and etherified melamine-formaldehyde resins may include one or more compounds of the following general formula: R1 and R2 are independently selected from H, -NH2, and C1-C8 alkyl, R3 is selected from H, -NH2, -NHR4, C1-C8 alkyl, C2-C8 alkenyl, phenyl, C7-C12 alkylphenyl, C7-C12 phenylalkyl, and C5-C8 cycloalkyl, and R4 is selected from -NH2 and C1-C8 alkyl. Optionally, R3 is selected from -NH2 or -NHR4.

[0166] Optionally, the amine-substituted triazine compound may include melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 6-ethyl-1,3,5-triazine-2,4-diamine, 6-isopropyl-1,3,5-triazine-2,4-diamine, 6-pentyl-2,4-diamino-1,3,5-triazine, 6-heptyl-2,4-diamino-triazine, 2- One or more of the following: vinyl-4,6-diamino-1,3,5-triazine, 2,4-diamino-6-(4-methylphenyl)-1,3,5-triazine, 6-cyclohexyl-1,3,5-triazine-2,4-diamine, 6-(3-methylphenyl)-1,3,5-triazine-2,4-diamine, 6-o-tolyl-1,3,5-triazine-2,4-diamine, 6-(2,4-dimethylphenyl)-1,3,5-triazine-2,4-diamine, 6-phenylmethyl-1,3,5-triazine-2,4-diamine, (diamino-1,3,5-triazine-2-yl)methanol, and 2-chloro-4,6-diamino-1,3,5-triazine.

[0167] Alternatively, the amine-substituted triazine compound may include one or more of melamine, benzomelamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazine, 2-amino-4-methylamino-1,3,5-triazine, and 2,4-diamino-6-dimethylamino-1,3,5-triazine.

[0168] Etherified melamine-formaldehyde resins may include one or more of partially etherified and fully etherified melamine-formaldehyde resins. Optionally, etherified melamine-formaldehyde resins may include fully etherified melamine-formaldehyde resins.

[0169] In some embodiments, etherified melamine aldehyde resins may include methyl etherified melamine aldehyde resins, diethyl etherified melamine aldehyde resins, butyl etherified melamine aldehyde resins, and methyl-butyl mixed etherified melamine aldehyde resins.

[0170] Optionally, the etherified melamine-formaldehyde resin may include one or more of the following: methyl etherified melamine-formaldehyde resin, butyl etherified melamine-formaldehyde resin, methyl etherified benzyl melamine-formaldehyde resin, and butyl etherified benzyl melamine-formaldehyde resin.

[0171] In some embodiments, the etherified melamine aldehyde resin may be in liquid form.

[0172] In some embodiments, the polyol may include one or more of diols, triols, and tetraols. Optionally, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethylbutyric acid, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyols, and polyester polyols. More preferably, the polyol may include one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, polyvinyl alcohol, and polyester polyols.

[0173] Optionally, the polyester polyol may include one or more of the following: polyethylene adipate diol, 1,4-butanediol adipate diol, propylene adipate diol, neopentyl adipate diol, neopentyl adipate-1,6-hexanediol adipate diol, hexanediol adipate diol, polycarbonate diol, and polycaprolactone diol.

[0174] Optionally, the polyether polyol may include one or more of polyoxypropylene glycol, polyoxypropylene triol, and polytetrahydrofuran glycol.

[0175] Optionally, the molecular weight of the polyester polyol can be below 5000, and optionally below 2000.

[0176] Optionally, the molecular weight of the polyether polyol can be below 5000, and optionally below 2000.

[0177] Optionally, the molecular weight of polyvinyl alcohol can be below 5000, and optionally below 2000.

[0178] In some embodiments, the polycarboxylic acid may include one or more of dicarboxylic acids, tricarboxylic acids, and tetracarboxylic acids. Optionally, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexanedicarboxylic acid, and 1,2-cyclohexanedicarboxylic acid. More preferably, the polycarboxylic acid may include one or more of oxalic acid, malonic acid, succinic acid, citric acid, phthalic acid, and terephthalic acid.

[0179] In some embodiments, the polyamide may include one or more of ethylene glycol, malonamide, succinamide, adipamide, and isophthalimide. Optionally, the polyamide may include one or more of ethylene glycol, malonamide, and isophthalimide.

[0180] 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 organic polymer particles of this disclosure or organic polymer particles prepared by the methods of this disclosure.

[0181] Both the porous base membrane and the coating have a porous structure, which allows the separator to have good air permeability, facilitating the passage of ions. The organic polymer particles in the coating are interconnected and fixed by a binder, and the gaps between the organic polymer particles can form a porous structure.

[0182] In some embodiments, the mass content of organic polymer particles in the coating may be 50%-99% based on the total mass of the coating.

[0183] Optionally, the mass content of organic polymer 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%.

[0184] In some embodiments, the adhesive in the coating may include, but is not limited to, one or more of polyacrylate adhesives and nitrile rubber adhesives.

[0185] In some embodiments, the coating may also include a dispersant. The dispersant may include, but is not limited to, one or more of polyacrylic acid dispersants and carboxymethyl cellulose dispersants.

[0186] In some embodiments, the separator may also include polymer binder particles.

[0187] 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.

[0188] In some embodiments, polymer binder particles may be embedded in organic polymer particles and form protrusions on the coating surface.

[0189] In other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer. The heat-resistant layer is disposed on a porous base membrane, and the adhesive layer is disposed on at least a portion of the surface of the heat-resistant layer on the side away from the porous base membrane. Organic polymer particles are disposed in the heat-resistant layer, and polymer adhesive particles are disposed in the adhesive layer.

[0190] In some other embodiments, the coating of the separator includes a heat-resistant layer and an adhesive layer, the heat-resistant layer being disposed on one side of the porous base membrane, the adhesive layer being disposed on at least a portion of the surface of the other side of the porous base membrane, organic polymer particles being disposed in the heat-resistant layer, and polymer adhesive particles being disposed in the adhesive layer.

[0191] In some embodiments, the average particle size of the polymer binder particles can be 6 μm-18 μm.

[0192] 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.

[0193] Comonomers may include at least one of olefin monomers, fluorinated olefin monomers, chlorinated olefin monomers, acrylate monomers, acrylic monomers, and fluoroether monomers.

[0194] 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).

[0195] 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.

[0196] In some embodiments, the areal density of the coating may be 0.45 g / m³. 2 -4.5g / m 2 .

[0197] 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.

[0198] 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.

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

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

[0201] In some embodiments, the ratio of the volume distribution particle size Dv50 of the organic polymer particles to the average pore size of the porous base membrane can be greater than or equal to 2.5.

[0202] The volume distribution particle size Dv50 of the organic polymer particles has the same unit, e.g., nm, as the average pore size of the porous base membrane.

[0203] This can reduce pore blockage and improve the air permeability and ion conduction properties of the separator.

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

[0205] 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.

[0206] 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.

[0207] In some embodiments, the longitudinal (MD) thermal shrinkage rate of the separator film can be less than or equal to 2.2% after being heated at a constant temperature of 130°C for 1 hour.

[0208] In some embodiments, the transverse (TD) heat shrinkage rate of the separator film can be less than or equal to 2.0% after being heated at a constant temperature of 130°C for 1 hour.

[0209] In some embodiments, the air permeability of the separator membrane can be 170s / 100ml-225s / 100ml.

[0210] In some embodiments, the longitudinal (MD) tensile strength of the separator membrane can be greater than or equal to 2100 kg / cm². 2 .

[0211] In some embodiments, the transverse (TD) tensile strength of the separator can be greater than or equal to 1800 kg / cm². 2 .

[0212] Organic polymer particles possess high hardness, high strength, and good abrasion resistance, which can improve the puncture strength of the separator. In some embodiments, the puncture strength of the separator can be greater than or equal to 405 kgf.

[0213] 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.

[0214] The separator membrane can be prepared according to methods known in the art.

[0215] In some embodiments, a slurry comprising organic polymer particles and a binder can be coated on at least one side of a porous base membrane, and after drying, a separation membrane is obtained.

[0216] In some embodiments, the slurry may further include polymer binder particles, which, after drying, are embedded in organic polymer particles and form protrusions on the coating surface.

[0217] In some embodiments, the method for preparing the separator membrane may include: applying a heat-resistant layer slurry comprising organic polymer particles and a binder to at least one side of a porous base membrane, and drying it to form a heat-resistant layer; and applying an adhesive layer slurry comprising polymer binder particles and a binder to at least a portion of the surface of the heat-resistant layer, and drying it to obtain the separator membrane.

[0218] In some embodiments, the method for preparing the separator membrane may include: coating a heat-resistant slurry comprising organic polymer 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.

[0219] In some embodiments, the solvent for the slurry may be water, such as deionized water.

[0220] In some embodiments, the slurry may also include other components, such as dispersants and / or wetting agents.

[0221] 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 both high reliability and high energy density.

[0222] 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.

[0223] 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.

[0224] [Positive electrode plate]

[0225] 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.

[0226] Taking a lithium-ion battery cell as an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds. Examples of lithium-containing phosphates may include, but are not limited to, lithium iron phosphate, lithium iron phosphate and carbon composites, lithium manganese phosphate, lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites, and their respective modified compounds. In some embodiments, to further improve the energy density of the secondary battery cell, the positive electrode active material may include materials with the general formula Li a Ni b Co c M d O e A fOne 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.

[0227] 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.

[0228] During the charging and discharging process, Li undergoes insertion / extraction and consumption in a single secondary battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before feeding. As the positive electrode active material is applied to a secondary battery cell, the molar Li content changes after charge-discharge cycles. Similarly, in the examples of positive electrode active materials in this disclosure, the molar O content is only a theoretical value. Lattice oxygen release causes changes in the molar O content, leading to fluctuations in the actual molar O content.

[0229] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3O2, 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.

[0230] 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.

[0231] 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.

[0232] 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.

[0233] 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.

[0234] 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.

[0235] [Negative electrode plate]

[0236] 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.

[0237] 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.

[0238] 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.

[0239] 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).

[0240] 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.

[0241] 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.

[0242] 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.

[0243] 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.

[0244] 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.

[0245] [Electrolytes]

[0246] The electrolyte plays a role in conducting ions between the positive and negative electrode plates.

[0247] In some embodiments, the electrolyte is an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0248] 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).

[0249] 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).

[0250] 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.

[0251] 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.

[0252] Optionally, the additive may include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propanesulfonate lactone (PS), and ethylene sulfate (DTD).

[0253] 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 electrolyte. After vacuum sealing, settling, and formation processes, a secondary battery cell is obtained.

[0254] Example

[0255] 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.

[0256] Commercially available melamine-formaldehyde resin granules were used as the organic polymer granules D1#. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.75:1.

[0257] Commercially available melamine-formaldehyde resin granules were cured in air at 250°C for 4 hours, followed by crushing, milling, sieving, and demagnetization to obtain organic polymer granules #1. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.75:1.

[0258] Commercially available melamine-formaldehyde resin granules were cured in air at 250°C for 6 hours, followed by crushing, milling, sieving, and demagnetization to obtain organic polymer granules #2. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.75:1.

[0259] Commercially available melamine-formaldehyde resin granules were cured in air at 280°C for 4 hours, followed by crushing, milling, sieving, and demagnetization to obtain organic polymer granules #3. The molar ratio of formaldehyde to melamine in the melamine-formaldehyde resin was 2.75:1.

[0260] Commercially available liquid hexamethoxymethyl melamine resin was cured in air at 250°C for 4 hours, and then crushed, milled, sieved and demagnetized to obtain organic polymer particles #4.

[0261] Commercially available liquid hexamethoxymethyl melamine resin was mixed with ethylene glycol at a molar ratio of 1:6 and cured in air at 250°C for 4 hours. After that, the mixture was crushed, milled, sieved and demagnetized to obtain organic polymer particles #5.

[0262] The DSC curves of the organic polymer particles 1# to 5# prepared above showed no melting endothermic peak in the range below 300℃.

[0263] The DSC curve of the commercially available organic polymer particles D1# has a melting endothermic peak in the range below 300℃, that is, it has a melting point, and the melting point (i.e. peak temperature) is between 110℃ and 140℃.

[0264] The DSC curve was obtained 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 with the lid; 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.

[0265] Organic polymer particle performance testing

[0266] (1) Glass transition temperature T of organic polymer particles g test

[0267] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. Determine whether the organic polymer particles have a glass transition temperature T below 300℃ using the DSC curve. g .

[0268] (2) Initial thermal weight loss temperature T of organic polymer particles 3d test

[0269] Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the alumina crucible of the thermogravimetric analyzer (TGA). Level the sample and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; temperature rise program: heating rate 10℃ / min, temperature range 35℃-600℃; obtain the temperature corresponding to a 3% loss of sample mass relative to the initial mass from the test curve, which is the initial thermogravimetric temperature T. 3d .

[0270] The organic polymer particles 1# to 5# prepared above also satisfy the following characteristics: no glass transition temperature T below 300℃. g .

[0271] A commercially available 7 μm thick polyethylene microporous membrane was used as the porous base membrane. The prepared organic polymer particles, along with the dispersant sodium carboxymethyl cellulose and the binder polyacrylate, were mixed evenly in deionized water at a solid mass ratio of 90:2:8 to obtain a slurry. The slurry was then... 2 The loading amount is uniformly coated on both surfaces of the porous base membrane.

[0272] The solvent was removed by drying to obtain the isolation membrane. The thickness of the coating on one side of the porous base membrane was 1.5 μm, and the thickness of the isolation membrane was 10 μm.

[0273] Performance testing

[0274] (1) Thermal shrinkage rate test of the separator film

[0275] The heat shrinkage rate test of the release liner can be referenced in GB / T 36363-2018.

[0276] 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.

[0277] 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.

[0278] 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.

[0279] (2) Tensile strength test of the separator

[0280] The tensile strength test of the separator can be referenced in GB / T 36363-2018.

[0281] The separator membrane samples were made into standard samples, and then subjected to tensile testing using a tensile testing machine until the samples broke. The maximum tensile force obtained was taken as the tensile strength of the separator membrane. The tensile rate was 50 mm / min. The average value of three parallel samples was taken as the test result.

[0282] (3) Puncture strength test of the isolation membrane

[0283] The puncture strength test of the separator can be referenced in GB / T 36363-2018.

[0284] Cut the release liner into strips, with a width greater than 10cm. Place the strips of release liner in the special clamp, ensuring the release liner is flat during placement. Ventilate the clamp to ensure it grips the release liner tightly. Turn on the universal testing instrument and set the needle movement speed to 50mm / min. When the needle punctures the release liner, a reading will appear on the computer screen connected to the universal testing instrument. Take the maximum value as the puncture strength of the release liner. Take 3 points during the test and take the average value as the puncture strength of the release liner.

[0285] Table 1

[0286] As can be seen from the above test results, the organic polymer particles prepared in this embodiment have good heat resistance, which can give the separator good heat resistance and high mechanical strength, thereby improving the thermal safety performance of the secondary battery cell.

[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 includes organic polymer particles containing triazine ring structural units, and the organic polymer particles have no melting endothermic peak in a differential scanning calorimetry curve at 300°C or lower.

2. The separator film according to claim 1, wherein The organic polymer particles include a bridging structure connecting the triazine ring structural units.

3. The separator film according to claim 2, wherein The bridging structure includes one or a combination of two or more of an alkylene group, an alkylene ether group, an alkylene amine group, an ester group, and an amide group.

4. The separator film according to any one of claims 1 to 3, wherein The triazine ring structural units further have a substituent group including one or a combination of two or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, and a hydroxyl group.

5. The separator film according to any one of claims 1 to 4, wherein The organic polymer particles include at least one of melamine formaldehyde polymers and derivatives thereof, etherified melamine formaldehyde polymers and derivatives thereof, etherified melamine formaldehyde-polyol polymers and derivatives thereof, etherified melamine formaldehyde-polycarboxylic acid polymers and derivatives thereof, and etherified melamine formaldehyde-polyamine amide polymers and derivatives thereof.

6. The separator film according to claim 5, wherein The melamine formaldehyde polymers and derivatives thereof include one or more of melamine formaldehyde, benzoguanamine formaldehyde, melamine-benzoguanamine formaldehyde, melamine-(2,4-diamino-1,3,5-triazine) formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine) formaldehyde, trihydrazino-s-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, and melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde; and / or The etherified melamine formaldehyde polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzoguanamine formaldehyde, and butyl etherified benzoguanamine formaldehyde; and / or The etherified melamine formaldehyde-polyol polymers and derivatives thereof include one or more of methyl etherified melamine formaldehyde-ethylene glycol polymer, methyl etherified melamine formaldehyde-1,2-propanediol polymer, methyl etherified melamine formaldehyde-1,4-butanediol polymer, methyl etherified melamine formaldehyde-polyester polyol polymer, methyl etherified melamine formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine formaldehyde-ethylene glycol polymer, butyl etherified melamine formaldehyde-1,2-propanediol polymer, butyl etherified melamine formaldehyde-1,4-butanediol polymer, and butyl etherified melamine formaldehyde-polyester polyol polymer; and / or The etherified melamine-aldehyde-polycarboxylic acid polymer and derivatives thereof include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malic acid polymer, a methyl etherified melamine formaldehyde-succinic acid polymer, a methyl etherified melamine formaldehyde-citric acid polymer, a methyl etherified melamine formaldehyde-terephthalic acid polymer, a methyl etherified melamine formaldehyde-phthalic acid polymer, a butyl etherified melamine formaldehyde-oxalic acid polymer, a butyl etherified melamine formaldehyde-malic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, and a butyl etherified melamine formaldehyde-phthalic acid polymer; and / or, The etherified melamine-aldehyde-polycarboxylic acid polymer and derivatives thereof include one or more of a methyl etherified melamine formaldehyde-oxalic acid polymer, a methyl etherified melamine formaldehyde-malic acid polymer, a methyl etherified melamine formaldehyde-succinic acid polymer, a methyl etherified melamine formaldehyde-citric acid polymer, a methyl etherified melamine formaldehyde-terephthalic acid polymer, a methyl etherified melamine formaldehyde-phthalic acid polymer, a butyl etherified melamine formaldehyde-oxalic acid polymer, a butyl etherified melamine formaldehyde-malic acid polymer, a butyl etherified melamine formaldehyde-citric acid polymer, a butyl etherified melamine formaldehyde-terephthalic acid polymer, and a butyl etherified melamine formaldehyde-phthalic acid polymer; and / or, 7. The separator film according to any one of claims 1 to 6, wherein The organic polymer particles are thermosetting resin; and / or, the organic polymer particles are amorphous polymer.

8. The separator film according to any one of claims 1 to 7, wherein, The organic polymer particles have no glass transition temperature below 300°C; and / or, The initial thermal weight loss temperature T 3d is 296°C - 340°C.

9. The separator film according to any one of claims 1 to 8, wherein, The volume distribution particle size Dv50 of the organic polymer particles is 200 nm to 820 nm; and / or, The true density of the organic polymer particles is 1.1 g / cm 3 -1.7 g / cm 3 .

10. The separator film according to any one of claims 1 to 9, wherein, The mass content of the organic polymer particles in the coating layer is 50% to 99% based on the total mass of the coating layer; and / or, The thickness of the coating layer is 0.5 μm to 5 μm; and / or, The areal density of the coating is 0.45 g / m 2 - 4.5 g / m 2 .

11. The separator film according to any one of claims 1 to 10, wherein The ratio of the volume distribution particle size Dv50 of the organic polymer particles to the average pore diameter of the porous base film is greater than or equal to 2.

5.

12. The separator film according to any one of claims 1 to 11, wherein The separator film satisfies one or more of the following conditions (1) to (6): (1) The separator film has a longitudinal heat shrinkage of less than or equal to 2.2% when heated at 130°C for 1 h; (2) The separator film has a transverse heat shrinkage of less than or equal to 2.0% when heated at 130°C for 1 h; (3) The separator film has an air permeability of 170 s / 100 ml to 225 s / 100 ml; (4) the release film has a longitudinal tensile strength of 2100 kg / cm or more 2 ; (5) the release film has a transverse tensile strength of 1800 kg / cm or more 2 ; (6) The separator film has a puncture strength of greater than or equal to 405 kgf.

13. An organic polymer particle, wherein, The organic polymer particles contain a triazine ring structural unit, and the differential scanning calorimetry curve of the organic polymer particles has no melting endothermic peak below 300°C.

14. The organic polymeric particles according to claim 13, wherein, The organic polymer particles include a bridging structure connecting the triazine ring structural units.

15. The organic polymeric particles according to claim 14, wherein, The bridging structure includes one or a combination of two or more of an alkylene group, an alkylene ether group, an alkylene amine group, an ester group, and an amide group.

16. The organic polymeric particles according to any one of claims 13-15, wherein, The triazine ring structural unit further has a substituent group including one or a combination of two or more of an alkyl group, an alkenyl group, a phenyl group, a cycloalkyl group, an amine group, and a hydroxyl group.

17. The organic polymeric particles according to any one of claims 13-16, wherein, The organic polymer particles include at least one of melamine formaldehyde polymer and derivatives thereof, etherified melamine formaldehyde polymer and derivatives thereof, etherified melamine formaldehyde-polyol polymer and derivatives thereof, etherified melamine formaldehyde-polycarboxylic acid polymer and derivatives thereof, etherified melamine formaldehyde-polyamine amide polymer and derivatives thereof.

18. The organic polymer particles according to claim 17, wherein The melamine formaldehyde polymer and derivatives thereof include one or more of melamine formaldehyde, benzotriazene formaldehyde, melamine-benzotriazene formaldehyde, melamine-(2,4-diamino-1,3,5-triazine) formaldehyde, melamine-(6-methyl-1,3,5-triazine-2,4-diamine) formaldehyde, melamine-(2,4,6-triethylamino-1,3,5-triazine) formaldehyde, trihydrazino-s-triazine formaldehyde, melamine-(2-amino-4-methylamino-1,3,5-triazine) formaldehyde, melamine-(2,4-diamino-6-dimethylamino-1,3,5-triazine) formaldehyde; and / or, The etherified melamine formaldehyde polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde, butyl etherified melamine formaldehyde, methyl etherified benzotriazene formaldehyde, butyl etherified benzotriazene formaldehyde; and / or, The etherified melamine formaldehyde-polyol polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde-ethylene glycol polymer, methyl etherified melamine formaldehyde-1,2-propanediol polymer, methyl etherified melamine formaldehyde-1,4-butanediol polymer, methyl etherified melamine formaldehyde-polyester polyol polymer, methyl etherified melamine formaldehyde-polyvinyl alcohol polymer, butyl etherified melamine formaldehyde-ethylene glycol polymer, butyl etherified melamine formaldehyde-1,2-propanediol polymer, butyl etherified melamine formaldehyde-1,4-butanediol polymer, butyl etherified melamine formaldehyde-polyester polyol polymer; and / or, The etherified melamine formaldehyde-polycarboxylic acid polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde-oxalic acid polymer, methyl etherified melamine formaldehyde-malic acid polymer, methyl etherified melamine formaldehyde-succinic acid polymer, methyl etherified melamine formaldehyde-citric acid polymer, methyl etherified melamine formaldehyde-terephthalic acid polymer, methyl etherified melamine formaldehyde-phthalic acid polymer, butyl etherified melamine formaldehyde-oxalic acid polymer, butyl etherified melamine formaldehyde-malic acid polymer, butyl etherified melamine formaldehyde-citric acid polymer, butyl etherified melamine formaldehyde-terephthalic acid polymer, butyl etherified melamine formaldehyde-phthalic acid polymer; and / or, The etherified melamine formaldehyde-polyamine amide polymer and derivatives thereof include one or more of methyl etherified melamine formaldehyde-oxamide polymer, methyl etherified melamine formaldehyde-malonamide polymer, methyl etherified melamine formaldehyde-isophthalic imide polymer, butyl etherified melamine formaldehyde-oxamide polymer.

19. The organic polymeric particles according to any one of claims 13 to 18, wherein, The organic polymer particles are thermosetting resin; and / or, the organic polymer particles are amorphous polymer.

20. The organic polymer particles according to any one of claims 13-19, wherein, The organic polymer particles have no glass transition temperature below 300℃; and / or, The initial thermal weight loss temperature T of the organic polymer particles 3d is 296°C - 340°C.

21. The organic polymer particles according to any one of claims 13-20, wherein, The volume distribution particle size Dv50 of the organic polymer particles is 200-820 nm; and / or, The true density of the organic polymer particles is 1.1 g / cm 3 -1.7 g / cm 3 .

22. A method for preparing organic polymer particles, comprising the following steps: providing a precursor containing triazine ring structure; heating and curing the precursor containing triazine ring structure under an oxygen-containing atmosphere, and then crushing to obtain organic polymer particles containing triazine ring structure units, wherein the heating and curing temperature is 180-280℃.

23. The method of claim 22, wherein, The heating and curing time is 1-6 hours.

24. The method of claim 22 or 23, wherein, The precursor containing triazine ring structure comprises at least one of melamine formaldehyde resin, etherified melamine formaldehyde resin, and a mixture of etherified melamine formaldehyde resin and at least one of polyol, polycarboxylic acid, and polyamide.

25. The method of claim 24, wherein, The precursor containing triazine ring structure comprises melamine formaldehyde resin, which is obtained by reacting an aldehyde compound with an amine-substituted triazine compound, wherein the amine-substituted triazine compound comprises melamine and / or melamine derivative.

26. The method of claim 25, wherein, The molar ratio of the aldehyde compound to the amine-substituted triazine compound is 1.7:1-3:

1.

27. The method of any one of claims 22-26, wherein, The precursor containing triazine ring structure comprises etherified melamine formaldehyde resin, which is obtained by reacting an aldehyde compound, an amine-substituted triazine compound, and an alcohol compound, wherein the amine-substituted triazine compound comprises melamine and / or melamine derivative.

28. The method of claim 27, wherein, The molar ratio of the aldehyde compound to the amine-substituted triazine compound is 4:1-7:

1.

29. The method according to any one of claims 25-28, wherein, The amine-substituted triazine compounds include one or more of the following general formula compounds, R1, R2are each independently selected from any one of H, -NH2, C1-C8 alkyl, R3is selected from any one of H, -NH2, -NHR4, C1-C8 alkyl, C2-C8 alkenyl, phenyl, C7-C12 alkylphenyl, C7-C12 phenylalkyl, C5-C8 cycloalkyl, and R4is selected from any one of -NH2, C1-C8 alkyl; and / or, The aldehyde compound comprises one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

30. The method of claim 27, wherein, The alcohol compound comprises one or more of methanol, ethanol, and butanol.

31. The method of any one of claims 25-30, wherein, The amine-substituted triazine compounds include one or more of melamine, benzoguanamine, 2,4-diamino-1,3,5-triazine, 6-methyl-1,3,5-triazine-2,4-diamine, 2,4,6-triethylamino-1,3,5-triazine, trihydrazino-s-triazine, 2-amino-4-methylamino-1,3,5-triazine, 2,4-diamino-6-dimethylamino-1,3,5-triazine, 6-ethyl-1,3,5-triazine-2,4-diamine, 6-isopropyl-1,3,5-triazine-2,4-diamine, 6-pentyl-2,4-diamino-1,3,5-triazine, 6-heptyl-2,4-diamino-triazine, 2-vinyl-4,6-diamino-1,3,5-triazine, 2,4-diamino-6-(4-methylphenyl)-1,3,5-triazine, 6-cyclohexyl-1,3,5-triazine-2,4-diamine, 6-(3-methylphenyl)-1,3,5-triazine-2,4-diamine, 6-o-tolyl-1,3,5-triazine-2,4-diamine, 6-(2,4-dimethylphenyl)-1,3,5-triazine-2,4-diamine, 6-phenylmethyl-1,3,5-triazine-2,4-diamine, (diamino-1,3,5-triazin-2-yl)methanol, 2-chloro-4,6-diamino-1,3,5-triazine.

32. The method of any one of claims 24-31, wherein, The etherified melamine formaldehyde resin includes one or more of methyl etherified melamine formaldehyde resin, butyl etherified melamine formaldehyde resin, methyl etherified benzoguanamine formaldehyde resin, butyl etherified benzoguanamine formaldehyde resin; and / or, The polyol includes one or more of ethylene glycol, 1,2-propanediol, 1,4-butanediol, neopentyl glycol, hexanediol, ethyl butyl propylene glycol, glycerol, trimethylolpropane, pentaerythritol, polyvinyl alcohol, polyether polyol, polyester polyol; and / or, The polycarboxylic acid includes one or more of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, citric acid, tartaric acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, maleic anhydride, 1,4-cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid; and / or, The polyamide includes one or more of oxamide, malonamide, succinamide, adipamide, isophthalic imide.

33. The method of any one of claims 24-32, wherein, The precursor containing triazine ring structure includes a mixture of etherified melamine formaldehyde resin and polyol, the molar ratio of the etherified melamine formaldehyde resin to the polyol is 1:2-1:6; or, The precursor containing triazine ring structure includes a mixture of etherified melamine formaldehyde resin and polycarboxylic acid, the molar ratio of the etherified melamine formaldehyde resin to the polycarboxylic acid is 1:2-1:6; or, The precursor containing a triazine ring structure includes a mixture of etherified melamine formaldehyde resin and a polybasic amide, and the molar ratio of the etherified melamine formaldehyde resin to the polybasic amide is 1:2-1:

6.

34. A secondary battery cell comprising a positive electrode sheet, a negative electrode sheet, and the separator of any one of claims 1-12 disposed between the positive electrode sheet and the negative electrode sheet.

35. A battery device comprising a plurality of the secondary battery cell of claim 34.

36. An electrically powered device comprising the secondary battery cell of claim 34 or the battery device of claim 35.

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