Separator and preparation method therefor, secondary battery, and electric device

Abstract

The present application provides a separator, a method for manufacturing the same, a secondary battery, and an electrical device. The separator comprises a substrate and a coating layer, wherein the coating layer is installed on at least one side of the substrate and the coating layer comprises an organic material. If the weight of a unit area of ​​a single-sided coating layer is M, the thickness of a single-sided coating layer is H, and the true density of the organic material is , the separator satisfies the following: where the unit of M is g / m², the unit of H is μm, and the unit of is g / cm³. Since the separator has characteristics such as good heat resistance and ion transport properties, the thermal safety performance and cycle performance of a battery using the separator can be improved.

Description

Technology Field This application belongs to the field of battery technology, and in particular relates to a separator and a method for manufacturing the same, a secondary battery, and an electrical device. Background Technology Batteries are widely applied in various fields, such as power tools, electric transportation, aerospace, and energy storage devices, due to their characteristics, including good electrochemical and safety performance. As batteries become more widespread and applied across diverse sectors, their thermal safety and cycle performance have become two key focus areas of battery performance. Currently, the thermal safety performance of batteries continues to degrade when exposed to heat, and their cycle performance also deteriorates. Therefore, it is urgent to improve the thermal safety and cycle performance of batteries. means of solving the problem The purpose of the present application is to provide a separator, a method for manufacturing the same, a secondary battery, and an electrical device. Since the separator has characteristics such as good heat resistance and ion transport properties, it can improve the thermal safety performance and cycle performance of a secondary battery using the separator. In the first aspect of the present application, a separation membrane comprising a substrate and a coating layer is provided, wherein the coating layer is installed on at least one side of the substrate, the coating layer comprises a particulate organic material, the weight of a unit area of ​​a single-sided coating layer is M, the thickness of a single-sided coating layer is H, and the true density of the organic material If done this way, the separator is Satisfies , where the unit of M is g / m 2 and the unit of H is μm, and The unit is g / cm 3 am. In the separation membrane according to the present application, the coating layer comprises a particulate organic material and the separation membrane Since this satisfies the conditions, on the one hand, organic materials within the coating layer can be reasonably deposited, and when the separator is heated, the mutual compression between the organic materials provides a force opposite to the direction of separator shrinkage, thereby reducing the degree of shrinkage of the separator. This reduces the risk of short circuits between the positive and negative electrodes in a battery using this separator, allowing the battery to have good thermal safety performance. On the other hand, while allowing organic materials to be reasonably deposited in the coating layer, more ion transport channels can be formed through the bonding between the organic materials. Furthermore, since the impregnation of the electrolyte into the separator and storage within the separator can be improved through these ion transport channels, it is advantageous for ion transport, thereby improving the cycle performance of the battery. In any embodiment of the present application, 0.5≤ ≤0.8. If the separator satisfies the above relationship, the organic material can be deposited more densely in the coating layer, thereby further reducing the degree of shrinkage of the separator so that the battery has good thermal safety performance and at the same time, the cycle performance of the battery can be further improved. In any embodiment of the present application, ≤2.5. Setting the true density of the organic material within the above appropriate range can help reduce the weight of the battery using this separator and improve the energy density per mass of the battery. In any embodiment of the present application, 0.8≤ ≤2.0. In any embodiment of the present application, M If the weight of a unit area of ​​a single-sided coating layer satisfies the above relationship, the organic material within the coating layer is deposited more densely so that adjacent organic materials can be bonded together, and when the separator is heated, the mutual compression between the organic materials can provide a force acting opposite to the direction of separator shrinkage, thereby further reducing the degree of separator shrinkage and reducing the occurrence of short circuits between the anode and cathode plates. In any embodiment of the present application, 0.7 M It is 3.0. In any embodiment of the present application, H ≤ 3.0. If the thickness (H) of the single-sided coating layer satisfies the above relationship, it facilitates dense deposition between organic materials, thereby further improving the thermal safety performance of the battery. In any embodiment of the present application, 0.5≤H≤2.0. In any embodiment of the present application, am. In any embodiment of the present application, 0.5≤ ≤1.0. In any embodiment of the present application, the mass percentage of the organic material in the coating layer is greater than or equal to 60%; optionally 75% to 95%. In any embodiment of the present application, the organic material comprises one or more of organosilicon compound particles, melamine-formaldehyde resin particles, phenol resin particles, polyester particles, polyimide particles, polyamideimide particles, aromatic polyamide particles, polyphenylene sulfide particles, polysulfone particles, polyethersulfone particles, polyetheretherketone particles, and polyaryletherketone particles; optionally, the organic material comprises organosilicon compound particles. In any embodiment of the present application, the organic material comprises organosilicon compound particles, the organosilicon compound particles comprise a first polymer, and the first polymer comprises a first structural unit, a second structural unit, and a third structural unit; The first structural unit has the structure shown in Equation (I); Equation (I); In formula (I), R1 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C5 alkyl group; optionally, R1 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C3 alkyl group; R2 comprises one or more of a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, and a substituted or unsubstituted C1-C20 hydroxyalkyl group; optionally, R2 comprises one or more of a C1-C12 alkyl group, a C3-C12 cycloalkyl group, and a C1-C12 hydroxyalkyl group; The second structural unit is as shown in Equation (II); Formula (II) In formula (II), R3 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C5 alkyl group; optionally, R3 has a hydrogen atom, or one or more of a substituted or unsubstituted C1-C3 alkyl group; The third structural unit is as shown in Equation (III); Equation (III) In formula (III), R4 to R 11 Each comprises an independently substituted or unsubstituted C1-C10 alkyl group, or one or more of the structural units shown in Formula (III-1), wherein R4 to R 11 At least one of them is a structural unit as shown in Equation (III-1); Equation (III-1) In Equation (III-1), R 12 comprises a hydrogen atom, or one or more of substituted or unsubstituted C1-C5 alkyl groups; optionally, R 12 ... comprises a hydrogen atom, or one or more of substituted or unsubstituted C1-C3 alkyl groups; R 13 comprises a substituted or unsubstituted C1-C10 alkyl group; optionally, R 13 It contains substituted or unsubstituted C3-C10 alkyl groups. In any embodiment of the present application, calculated based on the total molar mass of the first structural unit, the second structural unit, and the third structural unit, and with the molar content of the first structural unit being a%, 70 ≤ a ≤ 90; optionally, 75 ≤ a ≤ 85; and / or, calculated based on the total molar mass of the first structural unit, the second structural unit, and the third structural unit, and with the molar content of the second structural unit being b%, 0 <b≤18이고; 선택적으로, 2≤b≤8이고; 및 / 또는, 제1 구조단위, 제2 구조단위 및 제3 구조단위의 총 몰 질량을 기준으로 계산하고 제3 구조단위의 몰 함량을 c%로 하면, 0<c≤15이고; 선택적으로, 4≤c≤10이다. In any embodiment of the present application, the total molar mass of the first structural unit, the second structural unit, and the third structural unit is calculated, with the molar content of the first structural unit being a%, the molar content of the second structural unit being b%, and the molar content of the third structural unit being c%; and the organosilicon compound particles are under the following conditions: (1)5≤a / b≤10; (2)6≤a / c≤15; (3)a:b:c satisfies one or more of (14~16):(3~4):(1~4); In any embodiment of the present application, the organosilicon compound particles further comprise a second polymer, and the second polymer comprises a structural unit shown in formula (a); Equation (a) In equation (a), R 14 and R 15 Each comprises one or more of independently substituted or unsubstituted C1-C10 alkyl groups, hydroxyl groups, or amino groups; optionally, R 14 and R 15 Each comprises one or more of independently substituted or unsubstituted C1-C6 alkyl groups, hydroxyl groups, or amino groups. In any embodiment of the present application, the number average molecular weight of the organosilicon compound particles is 25,000 to 60,000, optionally 30,000 to 50,000. If the number average molecular weight of the organosilicon compound particles is within the above range, it is advantageous for forming organosilicon compound particles with smaller particle sizes, and when applied to a separator, a thin coating of the separator coating layer can be achieved, thereby reducing the overall thickness of the separator, thus facilitating the improvement of the energy density of the battery; furthermore, the risk of the organosilicon compound particles clogging the separator substrate can be reduced, thereby achieving the objective of improving performance such as the air permeability of the entire separator. In any embodiment of the present application, when calculated based on the mass of the organosilicon compound particles, the moisture content of the organosilicon compound particles is less than or equal to 3000 μg / g, and optionally 700 μg / g to 2500 μg / g. In any embodiment of the present application, the volume distribution particle size Dv90 of the organosilicon compound particles satisfies Dv90 ≤ 4.0 μm. By setting the Dv90 of the organosilicon compound particles within the above appropriate range, not only can the deposition density be improved, but the energy density of the battery can also be improved by ensuring that the coating layer has an appropriate thickness. In any embodiment of the present application, the volume distribution particle size Dv90 of the organosilicon compound particles satisfies 0.5μm≤Dv90≤30μm. In any embodiment of the present application, the volume distribution particle size Dv50 of the organosilicon compound particles satisfies 1.0μm≤Dv50≤2.5μm. In any embodiment of the present application, the particle size distribution of the organosilicon compound particles is 0.5≤(D V 90-D V 10) / D V It satisfies 50≤1.5. In any embodiment of the present application, the specific surface area of ​​the organosilicon compound particles is 35 m² 2 Less than or equal to / g, and optionally 5m 2 / g~30m 2 / g. If the specific surface area of ​​the organosilicon compound particles is set within the above appropriate range, the contact area between the organosilicon compound particles and the electrolyte can be increased, which helps to improve the electrolyte impregnation and liquid retention effects of the separator. In any embodiment of the present application, the thickness of the substrate is less than or equal to 12 μm. In any embodiment of the present application, the thickness of the substrate is 3 μm to 8 μm. In any embodiment of the present application, the substrate has a porous structure, and the porosity of the substrate is greater than or equal to 20%. In any embodiment of the present application, the porosity of the substrate is 25% to 45%. In any embodiment of the present application, the longitudinal thermal shrinkage rate of the separator at 150°C and 1h is less than or equal to 3%. In any embodiment of the present application, the transverse thermal shrinkage rate of the separator at 150°C and 1h is less than or equal to 2%. In any embodiment of the present application, the air permeability of the separator is less than or equal to 200s / 100mL. In any embodiment of the present application, the air permeability of the separator is 150 s / 100 mL to 200 s / 100 mL. In any embodiment of the present application, the longitudinal tensile strength of the separator is 2700 kgf / cm² 2 Greater than or equal to In any embodiment of the present application, the transverse tensile strength of the separator is 2500 kgf / cm² 2 Greater than or equal to In the second aspect of the present application, a method for manufacturing a separation membrane according to the first aspect of the present application is provided, Step of supplying materials; A step of preparing a coating layer slurry by mixing particulate organic material with a solvent; The method includes the step of forming a slurry film layer by coating a coating layer slurry on at least one side of a substrate, and forming a coating layer by drying the slurry film layer to obtain a separation membrane; Here, let M be the weight of the unit area of ​​the single-sided coating layer, let H be the thickness of the single-sided coating layer, and the true density of the organic material If done this way, the separator is Satisfies ≥0.4, where the unit of M is g / m 2 and the unit of H is μm, and The unit is g / cm 3 am. In the third aspect of the present application, a secondary battery is provided comprising a separator according to the first aspect of the present application or a separator obtained by a manufacturing method according to the second aspect of the present application. In the fourth aspect of the present application, an electric device comprising a secondary battery according to the third aspect of the present application is provided. Brief explanation of the drawing To more clearly explain the technical solution of the embodiments of the present application, the drawings used in the embodiments of the present application are briefly introduced below. The drawings introduced below represent only some embodiments of the present application, and it is evident that a person skilled in the art can obtain other drawings based on these drawings without creative effort. FIG. 1 is a schematic diagram of one embodiment of a secondary battery of the present application. Figure 2 is an exploded schematic diagram of an embodiment of the secondary battery of Figure 1. FIG. 3 is a schematic diagram of one embodiment of the battery module of the present application. FIG. 4 is a schematic diagram of one embodiment of the battery pack of the present application. Figure 5 is an exploded schematic diagram of an embodiment of the battery pack shown in Figure 4. FIG. 6 is a schematic diagram of one embodiment of an electric device using a secondary battery of the present application as a power source. In the diagram, the diagram is not necessarily drawn according to actual proportions. Specific details for implementing the invention Hereinafter, embodiments specifically disclosing the separator, the method of manufacturing the same, the secondary battery, and the electrical device of the present application will be described in detail with appropriate reference to the attached drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of known matters or repetitive descriptions of identical structures may be omitted. This is to avoid making the description below unnecessarily long and to aid the understanding of those skilled in the art. Furthermore, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the essence described in the claims. The 'range' disclosed in this application is limited in the form of lower and upper limits, and a given range is limited by the selection of one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of a specific range. A range limited in this manner may include or not include boundary values, and may also be arbitrarily combined. That is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, it can be understood that ranges of 60 to 110 and 80 to 120 are also expected. Furthermore, if minimum range values ​​1 and 2 and maximum range values ​​3, 4 and 5 are listed, ranges of 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 may all be expected. In this application, unless otherwise noted, a numeric range 'a to b' represents an abbreviated expression of any combination of real numbers from a to b, where a and b are real numbers. For example, the numeric range '0 to 5' indicates that all real numbers between '0 to 5' are listed here, and '0 to 5' is an abbreviated expression for these numeric combinations. Also, if a specific parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that this parameter is an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with one another to form a new technical solution, and such technical solution shall be deemed to be included in the disclosure of this application. Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application. Unless otherwise specified, all steps of the present application may proceed sequentially or randomly, preferably sequentially. For example, if the method comprises steps (a) and (b), it indicates that the method comprises steps (a) and (b) performed sequentially, or steps (b) and (a) performed sequentially. For example, if the method further comprises step (c), it indicates that step (c) may be added to the method in any order. For example, the method may comprise steps (a), (b), and (c), steps (a), (c), and (b), or steps (c), (a), and (b), etc. Unless otherwise specified, the terms 'include' and 'have' as used in this application are open forms and may also be closed forms. For example, the terms 'include' and 'have' may indicate that other unlisted components are included, or that only the listed components are included. Unless otherwise specified, the term “or” in this application is inclusive. For example, the phrase “A or B” indicates “A, B, or A and B.” More specifically, any of the following conditions satisfy the condition “A or B”: A being true (or existing) and B being false (or absent); A being false (or absent) and B being true (or existing); or both A and B being true (or existing). In this application, terms such as 'first', 'second', etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. In this application, the terms 'multiple' and 'various' mean two or more. Unless otherwise specified, the terms used in this application have the known meanings generally understood by those skilled in the art. Unless otherwise specified, the value of each parameter mentioned in this application may be measured according to various test methods commonly used in the art, for example, according to the test methods given in the embodiments of this application. In general, the battery includes an electrode assembly and an electrolyte, and the electrode assembly includes a positive plate, a negative plate, and a separator. The separator is installed between the positive plate and the negative plate to prevent a short circuit between the positive and negative electrodes, while simultaneously allowing active ions to pass freely to form a loop. Batteries are widely applied in various fields, such as power tools, electric transportation, aerospace, and energy storage devices, due to their characteristics, including good electrochemical and safety performance. As batteries become more widespread and applied across diverse sectors, their thermal safety and cycle performance have become two key focus areas of battery performance. Separators are an important component in improving the thermal safety and cycle performance of batteries. However, separators currently used in commercial batteries are generally porous polyolefin membranes with relatively low melting points, which cause significant thermal shrinkage when heated. This reduces ion transport pathways, thereby lowering ion conductivity and increasing the internal resistance of the battery, which in turn degrades its cycle performance. Furthermore, the shrinkage of the separator can cause the positive and negative electrodes inside the battery to come into direct contact, potentially leading to an internal short circuit and increasing safety risks for the battery. In light of this, the present application provides a separator, a method for manufacturing the same, a secondary battery, and an electrical device. Since the separator has characteristics such as good heat resistance and ion transport properties, it can improve the thermal safety performance and cycle performance of a battery using the separator. Separator In the first aspect of the present application, a separation membrane comprising a substrate and a coating layer is provided, wherein the coating layer is installed on at least one side of the substrate, the coating layer comprises a particulate organic material, the weight of a unit area of ​​a single-sided coating layer is M, the thickness of a single-sided coating layer is H, and the true density of the organic material If done this way, the separator is Satisfies , where the unit of M is g / m 2 and the unit of H is μm, and The unit is g / cm 3 am. In the separation membrane according to the present application, the coating layer comprises a particulate organic material and the separation membrane Since this satisfies the conditions, on the one hand, organic materials within the coating layer can be reasonably deposited, and when the separator is heated, the mutual compression between the organic materials provides a force opposite to the direction of separator shrinkage, thereby reducing the degree of shrinkage of the separator. This reduces the risk of short circuits between the positive and negative electrodes in a battery using this separator, allowing the battery to have good thermal safety performance. On the other hand, while allowing organic materials to be reasonably deposited in the coating layer, more ion transport channels can be formed through the bonding between the organic materials. Furthermore, since the impregnation of the electrolyte into the separator and storage within the separator can be improved through these ion transport channels, it is advantageous for ion transport, thereby improving the cycle performance of the battery. In some embodiments of the present application, the separator is 0.5≤ It satisfies ≤0.8. If the separator satisfies the above relationship, the organic material can be deposited more densely in the coating layer, thereby further reducing the degree of shrinkage of the separator, so that the battery has good thermal safety performance and at the same time, the cycle performance of the battery can be further improved. For example, is a range consisting of, but not limited to, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, or any two of the above values, and optionally, The value range of can be 0.4 to 0.8, 0.45 to 0.75, 0.5 to 0.7, 0.55 to 0.7, or 0.6 to 0.7. In some embodiments of the present application, the true density of the organic material Is It satisfies ≤2.5. Setting the true density of the organic material within the above appropriate range can help reduce the weight of the battery using this separator and improve the energy density per mass of the battery. In other embodiments of the present application, the true density of the organic material is 0.8≤ Satisfies ≤2.0. In some examples, the true density of organic materials is a range consisting of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, or any two of the above values, but is not limited thereto, optionally 0.1~2.5, 0.2~2.4, 0.3~2.3, 0.4~2.2, 0.5~2.1, 0.6~2.0, 0.7~1.9, 0.8~1.8, 0.9~1.7, 1.0~1.6, or 1.1~1.5. The true density of organic materials has a meaning known in the art and can be tested using methods already known in the art. For example, it can be tested by referring to GB / T 24586, and specifically, the following procedure can be referred to. A clean and dry sample cup is placed on a balance and set to zero, a powder sample is added to the sample cup in an amount approximately half the volume of the sample cup, and the sample mass is recorded. Then, the sample cup containing the sample is placed in a true density tester, nitrogen gas is injected according to the process in a closed test system, the pressure of the gas in the sample chamber and the expansion chamber is detected, and the true density is calculated by calculating the true volume according to Boyle's Law (PV=nRT). In some embodiments of the present application, the weight M of the unit area of ​​the single-sided coating layer satisfies M≥0.5. When the weight of the unit area of ​​the single-sided coating layer satisfies the above relationship, the organic material within the coating layer is deposited more densely so that adjacent organic materials can be bonded together, and when the separator is heated, the mutual compression between the organic materials can provide a force acting opposite to the direction of separator shrinkage, thereby further reducing the degree of shrinkage of the separator and reducing the occurrence of short circuits between the anode and cathode plates. In some other embodiments of the present application, the weight M of the unit area of ​​the single-sided coating layer is 0.7 M Meets 3.0. In some examples, the weight M of a unit area of ​​a single-sided coating layer may be a range consisting of 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 or any two of the above values, but is not limited thereto, and may be, for example, 0.5 to 2.0, 0.7 to 2.5, 0.75 to 2.0, 1.0 to 2.5, 1.0 to 2.0, or 1.0 to 1.8. The weight of a unit area of ​​a single-sided coating layer has a meaning known in the art and can be tested by methods already known in the art. For example, it can be tested according to the following procedure. A separator sample is cut into a small circular piece with an area of ​​S1, and its weight is measured and recorded as M1. Then, the coating layer of the weighed sample is removed, and the weight of the substrate is measured and recorded as M0; ① If the substrate has a coating layer on only one side, the weight of the unit area of ​​the single-side coating layer = (M1-M0) / S1 and; ② If the substrate has coating layers on both sides, the weight of the unit area of ​​the single-sided coating layer is (M1-M0) / S1 / 2. In some embodiments of the present application, the thickness (H) of the single-sided coating layer satisfies H ≤ 3.0. When the thickness (H) of the single-sided coating layer satisfies the above relationship, it facilitates dense deposition between organic materials. When the separator is heated, the dense deposition between organic materials can rapidly provide a force acting opposite to the direction of separator shrinkage, thereby further reducing the degree of separator shrinkage and reducing the occurrence of short circuits between the positive and negative plates, thereby achieving the objective of improving the thermal safety performance of the battery. In other embodiments of the present application, the thickness (H) of the coating layer satisfies 0.5≤H≤2.0. In some examples, the thickness (H) of the coating layer may be a range consisting of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 or any two of the above values, but is not limited thereto, and may be, for example, 0.5~2.5, 0.7~2.5, 0.8~2.8, 0.9~2.0, 1.0~2.5, 1.0~2.0. The thickness of a single-sided coating layer has a meaning known in the art and can be tested using methods already known in the art. For example, it can be tested with a thickness gauge by referring to the standard GB / T36363-2018 <Polyolefin Separator for Lithium-ion Batteries>. In some embodiments of the present application, the weight M of the unit area of ​​the single-sided coating layer and the thickness (H) of the single-sided coating layer are satisfies. In some embodiments of the present application, the weight M of the unit area of ​​the single-sided coating layer and the thickness (H) of the single-sided coating layer are 0.5≤ Satisfies ≤1.0. It should be noted that each coating layer parameter given in this application (e.g., thickness, weight per unit area, etc.) refers to a single-sided coating layer parameter. When coating layers are installed simultaneously on both sides of a substrate, if any one-sided coating layer parameter satisfies this application, it is deemed to fall within the scope of protection of this application. In some embodiments of the present application, the organic material comprises one or more of organosilicon compound particles, melamine-formaldehyde resin particles, phenol resin particles, polyester particles, polyimide particles, polyamideimide particles, aromatic polyamide particles, polyphenylene sulfide particles, polysulfone particles, polyethersulfone particles, polyetheretherketone particles, and polyaryletherketone particles. In some optional embodiments of the present application, the organic material comprises organosilicon compound particles. These organosilicon compound particles refer to an organosiloxane in which the main chain is a silicon-oxygen-silicon (-Si-O-Si-) bond. Since the silicon-oxygen-silicon bond is an inorganic bond and has high bond energy, very high heat resistance and chemical stability can be imparted to the organosilicon, for example, the organosilicon can be used for a long period at temperatures below 200°C. Other atomic groups may not be grafted onto the side chains of the organosilicon, or organic atomic groups may be grafted. When organic atomic groups are grafted, good dispersibility can be imparted to the organosilicon, thereby improving the coating performance of the organosilicon coating layer and its affinity with the substrate. By dispersing the organosilicon compound particles within the coating layer, the separator can have good heat resistance, thereby improving the thermal safety performance of the secondary battery. In addition, a structure having voids can be formed between organosilicon compound particles, and furthermore, since the electrolyte impregnation and retention characteristics of the separator can be improved to promote the transport of active ions in the separator, the cycle performance of the secondary battery can be improved when the separator is applied to a secondary battery. In some embodiments of the present application, the organosilicon compound particles comprise a first polymer, and the first polymer comprises a first structural unit, a second structural unit, and a third structural unit. The first structural unit has the structure shown in Equation (I); Equation (I) In formula (I), R1 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C5 alkyl group; optionally, R1 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C3 alkyl group; R2 comprises one or more of a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, and a substituted or unsubstituted C1-C20 hydroxyalkyl group; optionally, R2 comprises one or more of a C1-C12 alkyl group, a C3-C12 cycloalkyl group, and a C1-C12 hydroxyalkyl group; The second structural unit is as shown in Equation (II); Formula (II) In formula (II), R3 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C5 alkyl group; optionally, R3 has a hydrogen atom, or one or more of a substituted or unsubstituted C1-C3 alkyl group; The third structural unit is as shown in Equation (III); Equation (III) In formula (III), R4 to R 11 Each comprises an independently substituted or unsubstituted C1-C10 alkyl group, or one or more of the structural units shown in Formula (III-1), wherein R4 to R 11 At least one of them is a structural unit as shown in Equation (III-1); Equation (III-1) In Equation (III-1), R 12 comprises a hydrogen atom, or one or more of substituted or unsubstituted C1-C5 alkyl groups; optionally, R 12 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C3 alkyl group; R 13 comprises a substituted or unsubstituted C1-C10 alkyl group; optionally, R 13 It contains substituted or unsubstituted C3-C10 alkyl groups. In the above embodiments, the first structural unit can control the glass transition temperature of the first polymer, which helps to improve the toughness and peel strength of the polymer and to exhibit a good binding effect. The second structural unit has excellent anti-swelling properties and high binding properties, and when the first polymer is applied to the separator, the first polymer does not easily swell when it comes into contact with the electrolyte, thus having better anti-swelling properties. If the third structural unit contains a skeletal structure composed of Si-O-Si or Si-O bonds, it can provide the first polymer with advantages in terms of heat resistance and mechanical performance, and furthermore, ensures the thermal safety performance of the battery by ensuring that the separator has good thermal stability during the long-term cycle charge-discharge process of the battery, thereby effectively blocking the positive and negative plates. In addition, the combination of the first structural unit and the third structural unit can exhibit a synergistic effect to improve the binding properties and heat resistance of the first polymer; and the combination of the first structural unit and the second structural unit can exhibit a synergistic effect to improve the anti-swelling properties of the first polymer. Accordingly, the first polymer can not only improve the adhesion between the coating layer and the substrate but also improve the heat resistance of the separator, thereby improving the thermal safety performance of the battery. In some embodiments of the present application, when calculated based on the total molar mass of the first structural unit, the second structural unit, and the third structural unit, and the molar content of the first structural unit is a%, 70 ≤ a ≤ 90. If the molar content of the first structural unit is within the above range, the binding strength of the first polymer can be significantly improved; and when the first polymer is applied to a separator, the bonding strength between the first polymer and the substrate of the separator can be improved. Optionally, 75 ≤ a ≤ 85. For example, the molar content of the first structural unit may be a range consisting of 70%, 75%, 80%, 85%, 90%, or any two of the above values. In some embodiments of the present application, when calculated based on the total molar mass of the first structural unit, the second structural unit, and the third structural unit, and the molar content of the second structural unit is b%, 0 < b ≤ 18. If the molar content of the second structural unit is within the above range, the anti-swelling properties of the first polymer can be significantly improved. Optionally, 2 ≤ b ≤ 8. For example, the molar content of the second structural unit may be a range consisting of 5%, 8%, 10%, 12%, 15%, 18%, or any two of the above values. In some embodiments of the present application, when the molar content of the third structural unit is calculated based on the total molar mass of the first structural unit, the second structural unit, and the third structural unit and is denoted as c%, 0 < c ≤ 15. If the molar content of the third structural unit is within the above range, the heat resistance of the first polymer can be improved. Optionally, 4 ≤ c ≤ 10. For example, the molar content of the third structural unit may be a range consisting of 5%, 8%, 10%, 12%, 15%, or any two of the above values. Although the first structural unit within the first polymer can impart good binding properties to the first polymer, when the first polymer is applied to a separator, it inevitably comes into contact with the electrolyte, and the binding properties of the first polymer are reduced to some extent due to the swelling effect of the electrolyte. However, the cyanide group contained in the second structural unit within the first polymer can exert a synergistic effect with the first structural unit to jointly improve the anti-swelling properties and binding properties of the first polymer. Therefore, if the molar content a of the first structural unit and the molar content b of the second structural unit satisfy 5 ≤ a / b ≤ 10, the first structural unit can exert a more sufficient synergistic effect with the second structural unit to improve the binding properties and anti-swelling properties of the first polymer. For example, a / b may be a range consisting of 5, 6, 7, 8, or any two of the above values. The first structural unit within the first polymer can impart good binding properties to the first polymer, but its own heat resistance is relatively low; therefore, when the first polymer is applied to a separator, as the charging and discharging time of the battery increases, the temperature inside the battery rises, which may cause the destruction of the first structural unit; the first polymer further comprises a third structural unit, and the inorganic structure of polysilsesquioxane within the third structural unit can exert a synergistic effect with the first structural unit to improve the heat resistance and binding properties of the entire first polymer; thus, if the molar content a of the first structural unit and the molar content c of the third structural unit satisfy 6 ≤ a / c ≤ 15, the first structural unit can exert a more sufficient synergistic effect with the third structural unit to improve the binding properties and heat resistance of the first polymer. For example, a / c may be a range consisting of 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or any two of the above values. In some embodiments of the present application, the degree of polymerization a of the first structural unit, the degree of polymerization b of the second structural unit, and the degree of polymerization c of the third structural unit satisfy a:b:c=(14~16):(3~4):(1~4). When the degrees of polymerization of the first structural unit, the second structural unit, and the third structural unit satisfy the above ratio, the three structural units can cooperate with each other to jointly improve the cohesiveness, thermal stability, and anti-swelling properties of the polymer, based on the fact that the three structural units within the organosilicon compound particle each exhibit their respective performance advantages. The first structural unit includes various chemical structures, and the following describes the specific chemical structures of the first structural unit. In some embodiments of the present application, R1 includes a hydrogen atom and / or a methyl group. In some embodiments of the present application, R2 comprises one or more of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-octyl group, an isooctyl group, a 2-ethylhexyl group, a dodecyl group, or an isobornyl group. For example, the first structural unit includes one or more of the structures shown in Equation (I-1) to Equation (I-8). Equation (I-1), Equation (I-2), Equation (I-3), Equation (I-4), Equation (I-5), Equation (I-6), Formula (I-7), Equation (I-8). The second structural unit includes various chemical structures, and the following describes the specific chemical structures of the second structural unit. In some embodiments of the present application, R3 includes a hydrogen atom and / or a methyl group. For example, the second structural unit includes one or more of the structures shown in Formula (II-1) to Formula (II-4). Equation (II-1), Formula (II-2), Equation (II-3), Equation (II-4). The third structural unit includes various chemical structures, and the following describes the specific chemical structures of the third structural unit. In some embodiments of the present application, R4 to R 11 Each independently includes the structural unit shown in Equation (III-1); optionally, R 12 ... comprises one or more of a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, or an n-pentyl group; and / or R 13It includes one or more of an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-octyl group, an isooctyl group, or a 2-ethylhexyl group. In the present application, the type of atomic group in the first polymer can be measured by infrared spectroscopy. For example, the type of modified atomic group can be determined by determining the characteristic peaks included therein through an infrared spectrum test of the material. Specifically, an infrared spectrum analysis is performed on the material using a measuring instrument and method known in the art, for example, using an infrared spectrometer (e.g., the IS10 type Fourier transform infrared spectrometer of Nicolet, USA) and testing is performed in accordance with the general rules of the GB / T 6040-2019 infrared spectrum analysis method. In some embodiments of the present application, the infrared spectrum of the first polymer is 1750 cm⁻¹ -1 to 1735cm -1 There is a characteristic peak, which means that an ester group is present. In some embodiments of the present application, the infrared spectrum of the first polymer has 2260 cm⁻¹ -1 to 2220cm -1 There is a characteristic peak, which means that cyanide groups are present. In some embodiments of the present application, the infrared spectrum of the first polymer is 1100 cm⁻¹ -1 to 1120cm -1 There is a characteristic peak, which means that the Si-O-Si framework of silsesquioxane exists. In some embodiments of the present application, the first polymer may be prepared by the following method, and the method is, A step of supplying a first monomer, a second monomer, and a third monomer (S100); It includes a step (S200) of mixing a first monomer, a second monomer, and a third monomer, and carrying out a polymerization reaction under the action of an initiator to produce a first polymer. In the present application, a first monomer, a second monomer, and a third monomer are mixed and then copolymerized, and the formed first polymer is a copolymer of the three monomers. The first monomer has the structure shown in formula (IV); Formula (IV) In formula (IV), R1 is selected from a hydrogen atom, or a substituted or unsubstituted C1-C5 alkyl group; optionally, R1 is selected from a hydrogen atom, or a substituted or unsubstituted C1-C3 alkyl group; R2 is selected from substituted or unsubstituted C1-C20 alkyl groups, substituted or unsubstituted C3-C20 cycloalkyl groups, and substituted or unsubstituted C1-C20 hydroxyalkyl groups; optionally, R2 is selected from C1-C12 alkyl groups, C3-C12 cycloalkyl groups, and C1-C12 hydroxyalkyl groups. The first monomer is an acrylate-based compound, and during polymerization, the carbon-carbon double bond opens to form the first structural unit. For example, the first monomer comprises one or more of methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-octyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. The second monomer has the structure shown in formula (V); Equation (V) In formula (V), R3 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C5 alkyl group; optionally, R3 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C3 alkyl group. The second monomer is an acrylonitrile-based compound, and during polymerization, the carbon-carbon double bond opens to form a second structural unit. For example, the second monomer comprises acrylonitrile and / or methacrylonitrile. The third monomer has the structure shown in formula (VI); Equation (VI) In Equation (VI), R 30 to R 37 Each comprises an independently substituted or unsubstituted C1-C10 alkyl group, or one or more of the structural units shown in Formula (VI-1), wherein R 30 to R 37 At least one of them is a structural unit as shown in Equation (VI-1); Equation (VI-1) In Equation (VI-1), R 12 comprises a hydrogen atom, or one or more of substituted or unsubstituted C1-C5 alkyl groups; optionally, R 12 ... comprises a hydrogen atom, or one or more of substituted or unsubstituted C1-C3 alkyl groups; R 13 comprises a substituted or unsubstituted C1-C10 alkyl group; optionally, R 13 It contains substituted or unsubstituted C3-C10 alkyl groups. For example, the third monomer comprises one or more of methacryloxypropyl polyhedral oligomeric silsesquioxane, methacryloxypropyl heptisobutyl polysilsesquioxane, acryloxypropyl polyhedral oligomeric silsesquioxane, acryloxypropyl heptisobutyl polysilsesquioxane, and methacryloxypropyl heptoactyl polysilsesquioxane. In some embodiments of the present application, step (S200) specifically, A step (S210) of adding and mixing a first monomer, a second monomer, and a third monomer to a solvent and an emulsifier to form a mixed system; It includes the step (S220) of adding an initiator to a mixing system and proceeding with a polymerization reaction under the action of the initiator to produce a first polymer. In this application, the copolymerization of various monomers can be carried out via emulsion polymerization, making the polymerization method simpler. Of course, other polymerization methods such as solution polymerization and suspension polymerization may also be used in this application, and the process parameters used in the polymerization process may be selected from those generally used in the field, for which a detailed description is omitted herein.

[0155] In some embodiments of the present application, the emulsifier comprises one or more of sodium dodecyl sulfate, sodium dodecyl benzenesulfonate, alkyl diphenyl oxide disulfonate, and ethoxyalkylphenol ammonium sulfate. In some embodiments of the present application, when calculated based on the total mass of the mixed system, the ratio of the mass percentage content of the emulsifier to the mass percentage content of the first monomer, the second monomer, and the third monomer is 0.1% to 5%, that is, the amount of emulsifier used is 0.1% to 5% of the mass of the three monomers. If the mass percentage content of the emulsifier is within the above range, the first monomer, the second monomer, and the third monomer can be emulsified and dispersed in a solvent to form a relatively uniform system. In some embodiments of the present application, the initiator comprises potassium persulfate and / or ammonium persulfate. In some embodiments of the present application, when calculated based on the total mass of the mixed system, the ratio of the mass percentage content of the initiator to the mass percentage content of the first monomer, the second monomer, and the third monomer is 0.15% to 1%, that is, the amount of initiator used is 0.1% to 5% of the mass of the three monomers. If the mass percentage content of the initiator is within the above range, sufficient polymerization can be ensured. In some embodiments of the present application, the solvent may include water, such as deionized water. As a specific embodiment, the method is, A prepolymer preparation step of obtaining a prepolymer by mixing deionized water, an emulsifier, a first polymerization monomer, a second polymerization monomer, and a third polymerization monomer, and then stirring uniformly; The method comprises a first polymer preparation step in which an emulsifier and deionized water are added to a container and stirred and emulsified for 30 to 60 minutes to obtain a uniform and stable liquid, then the prepolymer prepared in the above step and an initiator solution (a solution formed by dissolving potassium persulfate and / or ammonium persulfate, which are initiators, in deionized water) are each slowly added dropwise, and after the addition is completed, the temperature is raised to 90°C to 110°C and the reaction is carried out while maintaining the temperature for 0.5 hours, then cooled to 40°C and adjusted the pH to 7 to 8 with ammonia water, then filtered and discharged, and a polymer is obtained through a drying process. In some embodiments of the present application, the organosilicon compound particles further comprise a second polymer, and the second polymer comprises a structural unit shown in formula (a); Equation (a) In equation (a), R 14 and R 15 is each independently selected from substituted or unsubstituted C1-C10 alkyl groups, hydroxyl groups, or amino groups. Optionally, R 14 and R15 Each is independently selected from a substituted or unsubstituted C1-C6 alkyl group, hydroxyl group, or amino group. For example, the organosilicon compound particles comprise at least one of the structures shown in formula (a-1) to the structure shown in formula (a-5). Equation (a-1), Equation (a-2), Equation (a-3), Equation (a-4), Equation (a-5). The first polymer and the second polymer in this application are used solely to distinguish material types and are not used as limitations regarding order and quantity. In some embodiments of the present application, the number average molecular weight of the organosilicon compound particles is 25,000 to 60,000, and optionally 30,000 to 50,000. For example, the number average molecular weight of the organosilicon compound particles may be a range consisting of 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 55,000, 60,000, or any two of the above values. If the number average molecular weight of the organosilicon compound particles is within the above range, it has a relatively high viscosity, which is advantageous for improving the bonding strength between the separator and the positive and negative plates when the organosilicon compound particles are applied to the separator. If the number average molecular weight of the organosilicon compound particles is within the above range, it is advantageous for forming organosilicon compound particles with a smaller particle size, and when applied to the separator, it enables a thin coating of the separator coating layer, thereby reducing the overall thickness of the separator, thus facilitating the improvement of the energy density of the secondary battery; In addition, since the particle size of the organosilicon compound particles formed by the polymer is not too small, the risk of the organosilicon compound particles clogging the membrane substrate is reduced, thereby improving performance such as the overall air permeability of the membrane. In the present application, the number average molecular weight of the first polymer can be tested through gel permeation chromatography (GPC). Specifically, the test can be performed using a GPC1515 type measuring instrument from Waters, USA, by dissolving the sample in tetrahydrofuran, with a dissolution time of 12 h or more and a sample concentration of 4 mg / mL, and preparing the sample by filtration, and then conducting the test at a test temperature of 25℃ and a test flow rate of 1 ml / min. As discovered by the inventor through further research, during the long-term charging and discharging process of a battery, moisture within the separator is gradually released and enters the electrolyte. Since the electrolyte has a relatively high sensitivity to moisture, hydrofluoric acid (HF) is easily generated by water, increasing the acidity of the electrolyte. Consequently, the active material and current collector corrode, and transition metal ions within the active material may leach out, which can affect the electrochemical performance of the battery. Therefore, this application controls the moisture content of organosilicon compound particles to be less than or equal to 3000 μg / g, optionally 700 μg / g to 2500 μg / g, and is calculated based on the mass of the organosilicon compound particles. If the moisture content of the organosilicon compound particles is within the above range, the included moisture content is relatively low, which reduces the risk of side reactions in the electrolyte during the long-term charging and discharging cycle of the battery, thereby improving the electrochemical performance of the battery. For example, the moisture content of the organosilicon compound particles may be in a range of 700 μg / g, 800 μg / g, 1000 μg / g, 1200 μg / g, 1500 μg / g, 1800 μg / g, 2000 μg / g, 2500 μg / g, 3000 μg / g, or any two of the above values. In the present application, the moisture content of organosilicon compound particles can be measured with a moisture meter, the test method can use the Karl Fischer moisture measurement method, and the measuring instrument can use the 831 type Karl Fischer moisture meter from Metrohm of Switzerland. In some embodiments of the present application, the volume distribution particle size Dv90 of the organosilicon compound particles satisfies Dv90 ≤ 2.0 μm. By setting the Dv90 of the organosilicon compound particles within the above appropriate range, not only can the deposition density be improved, but the energy density of the battery can also be improved by ensuring that the coating layer has an appropriate thickness. In other embodiments of the present application, the volume distribution particle size Dv90 of the organosilicon compound particles satisfies 0.5μm≤Dv90≤1.5μm. In some examples, the volume distribution particle size Dv90 of the organosilicon compound particles may be a range consisting of 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, 2.0 μm, or any two of the above values, but is not limited thereto. In some embodiments of the present application, the volume distribution particle size Dv50 of the organosilicon compound particles satisfies 1.0 μm ≤ Dv50 ≤ 2.5 μm; In some embodiments of the present application, the particle size distribution of the organosilicon compound particles is 0.5≤(D V 90-D V 10) / D V It satisfies 50≤1.5. In this application, the volume distribution particle size Dv90 of the material represents the particle size when the cumulative volume distribution percentage of the material reaches 90% in the sense known in the art, and can be measured using measuring instruments and methods already known in the art. For example, it can be tested with a laser diffraction particle size analyzer (e.g., Master Size 3000) by referring to GB / T 19077-2016 <Laser Diffraction Method for Particle Size Distribution>. In this application, the volume distribution particle size Dv50 of the material represents the particle size when the cumulative volume distribution percentage of the material reaches 50% in the sense known in the art, and can be measured using measuring instruments and methods already known in the art. For example, it can be tested with a laser diffraction particle size analyzer (e.g., Master Size 3000) by referring to GB / T 19077-2016 <Laser Diffraction Method for Particle Size Distribution>. In this application, the volume distribution particle size Dv10 of the material represents the particle size when the cumulative volume distribution percentage of the material reaches 10% in the sense known in the art, and can be measured using measuring instruments and methods already known in the art. For example, it can be tested with a laser diffraction particle size analyzer (e.g., Master Size 3000) by referring to GB / T 19077-2016 <Laser Diffraction Method for Particle Size Distribution>. In some embodiments of the present application, the specific surface area of ​​the organosilicon compound particles is 35 m² 2 Less than or equal to / g, and optionally 5m 2 / g~30m 2 / g. If the specific surface area of ​​the organosilicon compound particles is set within the above appropriate range, the contact area between the organosilicon compound particles and the electrolyte can be increased, which helps to improve the electrolyte impregnation and liquid retention effects of the separator. In this application, the specific surface area of ​​a particle has the meaning known in the art and can be measured using measuring instruments and methods already known in the art. For example, it can be obtained by testing using the nitrogen gas adsorption specific surface area analysis test method with reference to GB / T 19587-2017 and calculating using the BET (Brunauer-Emmett-Teller) method. Optionally, the nitrogen gas adsorption specific surface area analysis test can be performed using a Tri-Star 3020 specific surface area and pore size analyzer from Micromeritics, USA. In some examples, the specific surface area of ​​organosilicon compound particles is 3 m² 2 / g, 3.5m2 / g, 4m 2 / g, 4.5m 2 / g, 5m 2 / g, 5.5m 2 / g, 6m 2 / g, 6.5m 2 / g, 7m 2 / g, 7.5m 2 / g, 8m 2 / g, 8.5m 2 / g, 9m 2 / g, 9.5m 2 / g, 10m 2 / g, 10.5m 2 / g, 11m 2 / g, 11.5m 2 / g, 12m 2 / g, 12.5m 2 / g, 13m 2 / g, 13.5m 2 / g, 14m 2 / g, 14.5m 2 / g, 15m 2 / g, 15.5m 2 / g, 16m 2 / g, 16.5m 2 / g, 17m 2 / g, 17.5m 2 / g, 18m 2 / g, 19m 2 / g, 20m 2 / g, 21m 2 / g, 22m 2 / g, 23m 2 / g, 24m 2 / g, 25m 2 / g, 26m 2 / g, 27m 2 / g, 28m 2 / g, 29m 2 / g, 30m 2 / g, 31m 2 / g, 32m 2 / g, 33m 2 / g, 34m 2 / g, 35m 2 It may be a range consisting of / g or any two of the above values, but is not limited thereto. In some embodiments of the present application, the thickness of the substrate is less than or equal to 12 μm. Optionally, the thickness of the substrate is 3 μm to 8 μm. Since the coating layer of the present application can improve the thermal safety performance and cycle performance of the separator, a thinner substrate can be adopted, which helps to further improve the energy density of the battery. In some embodiments of the present application, the substrate has a porous structure, and the porosity of the substrate is greater than or equal to 20%. Optionally, the porosity of the substrate is 25% to 45%. If the porosity of the porous substrate is within the appropriate range, it is advantageous to further improve the ion transport characteristics of the separator and improve the cycle performance of the battery. In this application, there are no specific limitations on the material of the substrate, and any known substrate having good chemical and mechanical stability may be adopted. For example, the substrate may comprise at least one of a porous polyolefin-based resin film (e.g., at least one of polyethylene, polypropylene, and polyvinylidene fluoride), a porous glass fiber, and a porous nonwoven fabric. The porous substrate may be a single-layer thin film or a multilayer composite thin film. When the porous substrate is a multilayer composite thin film, the material of each layer may be the same or different. In some embodiments of the present application, the longitudinal thermal shrinkage rate of the separator at 150°C and 1h is less than or equal to 3%. In some embodiments of the present application, the transverse thermal shrinkage rate of the separator at 150°C and 1h is less than or equal to 2%. In the above embodiments, the separator of the present application has a low thermal shrinkage rate in both the transverse and longitudinal directions, so the thermal safety performance of the battery can be further improved. In some embodiments of the present application, the air permeability of the separator is less than or equal to 200 s / 100 mL. Optionally, the air permeability of the separator is 150 s / 100 mL to 200 s / 100 mL. Since the separator of the present application has good air permeability, it can improve ion transport characteristics, thereby lowering the resistance of the battery and improving the cycle performance of the battery. In some embodiments of the present application, the longitudinal tensile strength of the separator is 2700 kgf / cm 2 Greater than or equal to In some embodiments of the present application, the transverse tensile strength of the separator is 2500 kgf / cm² 2 Greater than or equal to In the above embodiments, the separator of the present application has high tensile strength in both the transverse and longitudinal directions, so the probability of the separator breaking when the battery expands is lower, and thus the safety performance of the battery can be further improved. In this application, the thermal shrinkage rate, tensile strength, and air permeability of the separator all have meanings known in the art and can be measured by methods already known in the art. For example, all can be tested by referring to the GB / T 36363-2018 standard. It should be noted that all coating layer parameters of the above separation membrane are coating layer parameters of a single side of the substrate. When a coating layer is installed on both sides of a substrate, if the parameters of the coating layer on any one side satisfy the present application, it is deemed to fall within the scope of protection of the present application. Method for manufacturing a separation membrane In a second aspect of the present application, a method for manufacturing a separation membrane according to the first aspect of the present application comprises the steps of: supplying a substrate (S1); preparing a coating layer slurry by mixing a particulate organic material with a solvent (S2); coating the coating layer slurry on at least one side of the substrate to form a slurry film layer, and drying the slurry film layer to form a coating layer and obtain a separation membrane (S3); wherein the weight of a unit area of ​​a single-sided coating layer is M, the thickness of a single-sided coating layer is H, and the true density of the organic material If done this way, the separator is Satisfies ≥0.4, where the unit of M is g / m 2 and the unit of H is μm and The unit is g / cm 3 am. In some embodiments of the present application, in S2, the solvent may be water, such as deionized water. The binder may be an aqueous binder, which is advantageous for the preparation and coating of the coating layer slurry because it has good thermodynamic stability and is environmentally friendly. As an example, the aqueous binder may include at least one of an aqueous acrylic acid-based resin (e.g., acrylic acid, methacrylic acid, sodium acrylate monomer homopolymer or copolymer with other copolymer monomers), polyvinyl alcohol (PVA), isobutylene-maleic anhydride copolymer, and polyacrylamide. Additionally, the coating layer slurry may also include other components such as a dispersant, a wetting agent, etc. In some embodiments of the present application, at S3, the coating is performed using a coating machine. The present application does not specifically limit the model type of the coating machine, and, for example, a commercially available coating machine may be used. Optionally, the coating machine includes a gravure roller, and the gravure roller is used to transfer the coating layer slurry onto a substrate. Optionally, the number of strokes of the gravure roller is 100 LPI to 200 LPI, and more optionally 150 LPI to 180 LPI. Additionally, the coating method may adopt transfer coating, spray coating, immersion coating, etc. In some embodiments of the present application, at S3, the coating speed can be controlled to 30 m / min to 120 m / min, for example, 60 m / min to 90 m / min. If the coating speed is within the above range, the problem of the coating layer surface can be effectively reduced and the probability of coating non-uniformity occurring can be lowered, thereby further improving the energy density and safety performance of the battery. By controlling each of the above process parameters within a given range, the performance of the membrane of the present application can be further improved. A person skilled in the art may selectively adjust one or more of the above process parameters according to actual conditions. The method for manufacturing a separation membrane according to the present application manufactures a coating layer through a single coating process, thereby significantly simplifying the production process of the separation membrane. Parameters such as some raw materials and their contents used in the method for manufacturing a separation membrane of the present application can be described by referring to the separation membrane according to the first aspect of the embodiment of the present application, so a detailed description is omitted here. Unless otherwise specified, each raw material used in the method for manufacturing a separation membrane of the present application can be obtained by purchasing it commercially. secondary battery In the third aspect of the embodiment of the present application, a secondary battery is provided. A secondary battery is also referred to as a rechargeable battery or a storage battery, and it refers to a battery that can be continuously used by activating an active material through a charging method after discharge. In general, the secondary battery comprises an electrode assembly and an electrolyte, and the electrode assembly comprises a positive plate, a negative plate, and a separator, and the separator is installed between the positive plate and the negative plate to prevent a short circuit between the positive and negative electrodes while simultaneously allowing active ions to pass through. In this application, there are no specific restrictions on the type of secondary battery, and for example, the secondary battery may be a lithium-ion battery, a sodium-ion battery, etc., and in particular, the secondary battery may be a lithium-ion secondary battery. The secondary battery of the present application comprises a separator according to the first aspect of the present application or a separator obtained through a manufacturing method according to the second aspect of the present application, wherein the separator is interposed between a positive plate and a negative plate. Optionally, at least one side of the separator adjacent to the negative plate has a coating layer of the present application. Accordingly, the secondary battery of the present application has better thermal safety performance and cycle performance. [Polar Plate] In some embodiments of the present application, the anode plate comprises an anode current collector and an anode film layer installed on at least one side of the anode current collector and comprising an anode active material. For example, the anode current collector has two opposing sides in its thickness direction, and the anode film layer is installed on any one or both of the two opposing surfaces of the anode current collector. When the secondary battery of the present application is a lithium-ion secondary battery, the positive electrode active material may include, but is not limited to, at least one of a lithium-containing transition metal oxide, a lithium-containing phosphate, and a modified compound thereof. Examples of lithium transition metal oxides may include, but are not limited to, at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and a modified compound thereof. Examples of lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, a composite material of lithium iron manganese phosphate and carbon, and a modified compound thereof. In some embodiments of the present application, to further improve the energy density of the secondary battery, the positive active material used in the lithium-ion secondary battery is of the form Li a Ni b Co c M d O e A f It may include at least one of a lithium transition metal oxide and a modified compound thereof. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M is at least one selected from Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A is at least one selected from N, F, S and Cl. As an example, the positive active materials used in lithium-ion secondary batteries are LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3O2(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 0.15 Al 0.05 It may include at least one of O2, LiFePO4, and LiMnPO4. In the case where the secondary battery of the present application is a sodium-ion secondary battery, the positive active material may include at least one of a sodium-containing transition metal oxide, a polyanionic material (e.g., phosphate, fluorophosphate, pyrophosphate, sulfate, etc.), and a Prussian blue-based material, but is not limited thereto. As an example, the positive active materials used in sodium-ion secondary batteries are NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2 Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue materials, general dietary X p M' q (PO4) r O x Y 3-x It may include at least one of the ingredients. Common food X p M' q (PO4) r O x Y 3-x At 0<p≤4, 0<q≤2, 1≤r≤3, 0≤x≤2, and X is H + , Li + , Na + , K + and NH4 +At least one selected from among, M' is a transition metal cation, optionally at least one selected from V, Ti, Mn, Fe, Co, Ni, Cu and Zn, Y is a halogen anion, optionally at least one selected from F, Cl and Br. In the present application, the modified compound of each anode active material may be modified by doping of the anode active material and / or modified by surface coating. In some embodiments of the present application, the anode film layer optionally further comprises an anode conductive agent. The present application does not particularly limit the type of anode conductive agent, and as an example, the anode conductive agent comprises at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon quantum dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments of the present application, the mass percentage content of the anode conductive agent is ≤6 wt% based on the total weight of the anode film layer. In some embodiments of the present application, the anode film layer optionally further comprises an anode binder. The present application does not particularly limit the type of anode binder, and as an example, the anode binder may comprise at least one of polyvinylidene difluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate-based resin. In some embodiments of the present application, the mass percentage content of the anode binder is ≤5 wt% based on the total weight of the anode film layer. In some embodiments of the present application, a metal foil or a composite current collector may be used as the positive current collector. An aluminum foil may be adopted as an example of the metal foil. The composite current collector may include a polymer material substrate layer and a metal material layer formed on at least one side of the polymer material substrate layer. As an example, the metal material may include at least one of aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material substrate layer may include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE). The anode film layer is generally formed by coating an anode slurry onto an anode current collector, followed by drying and cold pressing. The anode slurry is generally formed by dispersing an anode active material, an optional conductive agent, an optional binder, and any other components in a solvent and stirring uniformly. The solvent may be N-methylpyrrolidone (NMP), but is not limited thereto. [Cathode] In some embodiments of the present application, the cathode plate comprises a cathode current collector and a cathode film layer installed on at least one side of the cathode current collector and comprising a cathode active material. For example, the cathode current collector has two opposing sides in its thickness direction, and the cathode film layer is installed on any one or both of the two opposing surfaces of the cathode current collector. As a negative electrode active material, a negative electrode active material for a secondary battery known in the art may be used. As an example, the negative electrode active material may include, but is not limited to, at least one of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may include at least one of silicon element, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloy materials. Tin-based materials may include at least one of tin element, tin oxide, and tin alloy materials. In some embodiments of the present application, the cathode film layer optionally further comprises a cathode conductive agent. The present application does not particularly limit the type of cathode conductive agent, and as an example, the cathode conductive agent may comprise at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon quantum dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments of the present application, the mass percentage content of the cathode conductive agent is ≤7 wt% based on the total weight of the cathode film layer. In some embodiments of the present application, the cathode film layer optionally further comprises a cathode binder. The present application does not particularly limit the type of cathode binder, and as an example, the cathode binder may comprise at least one of styrene butadiene rubber (SBR), water-soluble unsaturated resin (SR-1B), water-soluble acrylic acid-based resin (e.g., polyacrylic acid (PAA), polymethacrylic acid (PMAA), sodium polyacrylate (PAAS)), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments of the present application, the mass percentage content of the cathode binder is ≤6 wt% based on the total weight of the cathode film layer. In some embodiments of the present application, the cathode film layer optionally further comprises other auxiliary agents. As an example, other auxiliary agents may include thickeners such as sodium carboxymethylcellulose (CMC), PTC thermistor materials, etc. In some embodiments of the present application, the mass percentage content of other auxiliary agents is ≤3 wt% based on the total weight of the cathode film layer. In some embodiments of the present application, a metal foil or a composite current collector may be used as the negative current collector. Copper foil may be adopted as an example of the metal foil. The composite current collector may include a polymer material substrate layer and a metal material layer formed on at least one side of the polymer material substrate layer. As an example, the metal material may include at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material substrate layer may include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE). The cathode film layer is generally formed by coating a cathode slurry onto a cathode current collector, followed by drying and cold pressing. The cathode slurry is generally formed by dispersing a cathode active material, an optional conductive agent, an optional binder, and other optional auxiliary agents in a solvent and stirring uniformly. The solvent may be N-methylpyrrolidone (NMP) or deionized water, but is not limited thereto. The cathode plate may also include additional functional layers other than the cathode film layer. For example, in some embodiments, the cathode plate of the present application further comprises a conductive base coating layer (e.g., composed of a conductive agent and a binder) interposed between the cathode current collector and the cathode film layer and installed on the surface of the cathode current collector. In other embodiments, the cathode plate of the present application also comprises a protective layer covering the surface of the cathode film layer. [Electrolyte] During the charging and discharging process of a secondary battery, active ions reciprocate between the positive and negative plates, undergoing insertion and extraction, while the electrolyte plays the role of conducting active ions between the positive and negative plates. In this application, the type of electrolyte is not specifically limited and can be selected according to actual requirements. The electrolyte comprises an electrolyte salt and a solvent. The types of electrolyte salt and solvent are not subject to specific limitations and can be selected according to actual requirements. In the case where the secondary battery of the present application is a lithium-ion secondary battery, as an example, the electrolyte salt may include, but is not limited to, at least one of 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 difluoro(oxalato)borate (LiDFOB), lithium bis(oxalato)borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluoro(oxalato)phosphate (LiDFOP), and lithium tetrafluoro(oxalato)phosphate (LiTFOP). In the case where the secondary battery of the present application is a sodium-ion secondary battery, as an example, the electrolyte salt may include, but is not limited to, at least one of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bis(fluorosulfonyl)imide (NaFSI), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluoro(oxalato)borate (NaDFOB), sodium bis(oxalato)borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluoro(oxalato)phosphate (NaDFOP), and sodium tetrafluoro(oxalato)phosphate (NaTFOP). As an example, the solvent may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propylene propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), gamma butyrolactone (GBL), sulforain (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS), and diethyl sulfone (ESE). In some embodiments of the present application, the electrolyte optionally further comprises additives. For example, the additives may include a cathode film-forming additive or an anode film-forming additive, and may further include additives capable of improving specific performance of the secondary battery, such as an additive that improves the overcharge performance of the secondary battery, an additive that improves the high-temperature performance of the secondary battery, an additive that improves the low-temperature performance of the secondary battery, etc. In some embodiments of the present application, the anode plate, separator, and cathode plate may be manufactured into an electrode assembly through a winding process and / or a lamination process. In some embodiments of the present application, the secondary battery may further include an outer packaging. This outer packaging may be used to package the electrode assembly and the electrolyte. In some embodiments of the present application, the outer packaging of the secondary battery may be a rigid case, such as a rigid plastic case, an aluminum case, a steel case, etc. The outer packaging of the secondary battery may be a pouch, such as a pocket-type pouch. The material of the pouch may be plastic, for example, at least one of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS). In this application, the shape of the secondary battery is not specifically limited and may be cylindrical, prismatic, or any other shape. FIG. 1 is a secondary battery (5) with a prismatic structure as an example. In some embodiments of the present application, as illustrated in FIG. 2, the outer packaging may include a housing (51) and a cover plate (53). The housing (51) may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate may surround to form a receiving chamber. The housing (51) has an opening communicating with the receiving chamber, and the cover plate (53) is used to cover the opening to close the receiving chamber. The positive plate, the negative plate, and the separator may form an electrode assembly (52) through a winding process and / or a lamination process. The electrode assembly (52) is packaged within the receiving chamber. An electrolyte is impregnated into the electrode assembly (52). The number of electrode assemblies (52) included in the secondary battery (5) may be one or many and may be adjusted according to actual requirements. A method for manufacturing a secondary battery according to the present application is known. In some embodiments of the present application, a secondary battery may be formed by assembling a positive plate, a separator, a negative plate, and an electrolyte. As an example, an electrode assembly may be formed from a positive plate, a separator, and a negative plate through a winding process and / or a lamination process, the electrode assembly may be placed in an outer package and dried, an electrolyte may be injected, and a secondary battery may be obtained through processes such as vacuum packaging, settling, formation, and molding. In some embodiments of the present application, the secondary battery according to the present application may be assembled into a battery module, and the number of secondary batteries included in the battery module may be multiple, and the specific number may be adjusted according to the application and capacity of the battery module. FIG. 3 is a schematic diagram of a battery module as an example. As shown in FIG. 3, in the battery module (4), a plurality of secondary batteries (5) may be arranged sequentially along the length direction of the battery module (4). Of course, they may also be arranged in any other arbitrary manner. Furthermore, a plurality of secondary batteries (5) may be fixed by a fixing member. Optionally, the battery module (4) may further include a case having a receiving space, and a plurality of secondary batteries (5) are received in this receiving space. In some embodiments of the present application, the battery module may be assembled into a battery pack, and the number of battery modules included in the battery pack may be adjusted according to the application and capacity of the battery pack. FIGS. 4 and 5 are schematic diagrams of a battery pack (1) as an example. As illustrated in FIGS. 4 and 5, the battery pack (1) may include a battery box and a plurality of battery modules (4) installed within the battery box. The battery box includes an upper box (2) and a lower box (3), and the upper box (2) is used to cover the lower box (3) to form a closed space for accommodating the battery modules (4). The plurality of battery modules (4) may be arranged within the battery box in any manner. electrical devices In a fourth aspect of the embodiment of the present application, an electric device is provided, and the electric device comprises at least one of a secondary battery, a battery module, or a secondary battery pack according to the third aspect of the present application. The secondary battery, battery module, or battery pack may be used as a power source for the electric device or as an energy storage device for the electric device. The electric device may be, but is not limited to, a mobile device (e.g., mobile phone, laptop, etc.), an electric vehicle (e.g., pure electric vehicle, hybrid electric vehicle, plug-in hybrid electric vehicle, electric bicycle, electric scooter, electric golf cart, electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc. Electrical devices can select secondary batteries, battery modules, or battery packs depending on usage requirements. FIG. 6 is a schematic diagram of an electric device as an example. This electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the high output and high energy density requirements of the electric device, a battery pack or battery module may be used. As another example, electrical devices can be mobile phones, tablet PCs, laptops, etc. Since these devices generally require lightweight design, secondary batteries can be used as a power source. The following embodiments provide a more detailed explanation of the contents disclosed in this application, and since various modifications and changes made within the scope of the contents disclosed in this application are obvious to those skilled in the art, these embodiments are used for illustrative purposes only. Unless otherwise specified, all parts, percentages, and ratios described in the embodiments below are calculated based on mass, all timepieces used in the embodiments can be obtained by commercial purchase or synthesized according to conventional methods and can be used directly without further processing, and the measuring instruments used in the embodiments can be obtained by commercial purchase. Example 1 Preparation of organosilicon compound particles Prepolymer preparation step: 300g of deionized water and 1.5g of sodium dodecyl sulfate are each added to a 5L 3-neck flask and stirred and emulsified for 30 minutes at a rotational speed of 1500r / min to obtain a uniform and stable emulsion, and then 137.74g of methyl acrylate, 15.9g of acrylonitrile, and 66.35g of methacryloxypropyl polyhedral oligomeric silsesquioxane (the molar content ratio of methyl acrylate, acrylonitrile, and methacryloxypropyl polyhedral oligomeric silsesquioxane is 16:3:1) are added, and then stirred for 30 minutes at a rotational speed of 1500r / min to obtain a uniform prepolymer. Preparation step of organosilicon compound particles: 0.6g of sodium dodecyl sulfate and 200g of deionized water are added to a dry 3-necked flask and stirred and emulsified at high speed for 30 min to obtain a uniform and stable emulsion; Next, using a peristaltic pump, the prepolymer prepared in the previous step and the initiator solution (a solution formed by dissolving 0.6 g of potassium persulfate in 10 g of deionized water) are slowly added dropwise, respectively. After the addition is complete, the temperature is raised to 90°C and maintained for 0.5 hours to allow the reaction to proceed. After cooling to 40°C, the pH is adjusted to 7–8 using ammonia water. Subsequently, the mixture is filtered and discharged. Following a drying process, organosilicon compound particles with a number average molecular weight of 25,473 are obtained and recorded as O1. The water content of O1 is 1,000 μg / g, the volume distribution particle size Dv90 is 1.5 μm, the volume distribution particle size Dv50 is 1.2 μm, the volume distribution particle size Dv10 is 0.4 μm, and the specific surface area is 20 m². 2 / g is. Manufacturing of separation membranes PE substrate supply stage: The thickness is 6 μm and the porosity is 30%. Coating layer slurry preparation step: Organosilicon compound particles (O1) and polyvinyl alcohol are mixed with water in proportion (mass ratio is 8:2) to prepare a coating layer slurry. Coating step: The prepared coating layer slurry is coated onto both sides of the PE substrate using a coating machine, and a separation membrane is obtained through drying and slitting processes. Manufacturing of anode plates LiNi, an active material 0.5 Co 0.2 Mn 0.3 O2 (NCM523), acetylene black as a conductive agent, and polyvinylidene difluoride as a binder are uniformly mixed in an appropriate amount of N-methylpyrrolidone (NMP) as a solvent in a weight ratio of 94:3:3 to obtain an anode slurry; the anode slurry is coated onto an aluminum foil as an anode current collector, and an anode plate is obtained through processes such as drying, cold pressing, slitting, and cutting. Manufacturing of cathode plates Artificial graphite as a cathode active material, carbon black (Super P) as a conductive agent, styrene butadiene rubber (SBR) as a binder, and sodium carboxymethylcellulose (CMC) are uniformly mixed in an appropriate amount of deionized water as a solvent in a mass ratio of 95:2:2:1 to obtain a cathode slurry, the cathode slurry is coated onto a copper foil as a cathode current collector, and a cathode plate is obtained through drying, cold pressing, slitting, and cutting processes. Preparation of electrolyte An organic solvent is obtained by mixing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a mass ratio of 30:70, and sufficiently dried LiPF6 is dissolved in the organic solvent to prepare an electrolyte with a concentration of 1 mol / L. manufacturing of battery cells An electrode assembly is obtained by sequentially stacking a positive plate, a separator, and a negative plate and then winding them; the electrode assembly is placed in an outer package, dried, and then an electrolyte is injected, and a battery cell is obtained through processes such as vacuum packaging, settling, formation, and molding. Examples 2 to 12 The battery cell is manufactured in a manner similar to Example 1, with the difference being the parameters related to the coating layer of the separator. In this example 10, the type of organosilicon compound particles differs from other examples, and specific parameters can be found in Table 1. In Example 10, the method for preparing organosilicon compound particles is as follows. Prepolymer preparation step: 1400g of deionized water and 7g of sodium dodecyl sulfate are each added to a 5L 3-neck flask and stirred and emulsified for 30 minutes at a rotational speed of 1500r / min to obtain a uniform and stable emulsion, and then 645.68g of methyl acrylate, 75.59g of acrylonitrile, and 663.50g of methacryloxypropyl polyhedral oligomeric silsesquioxane (the molar content ratio of methyl acrylate, acrylonitrile, and methacryloxypropyl polyhedral oligomeric silsesquioxane is 15:3:2) are added, and then stirred for 30 minutes at a rotational speed of 1500r / min to obtain a uniform prepolymer. Preparation step of organosilicon compound particles: 3g of sodium dodecyl sulfate and 1000g of deionized water are added to a dry 3-necked flask and stirred and emulsified at high speed for 30 min to obtain a uniform and stable emulsion; Next, using a peristaltic pump, the prepolymer prepared in the previous step and the initiator solution (a solution formed by dissolving 3g of potassium persulfate in 30g of deionized water) were slowly added dropwise, respectively. After the addition was complete, the temperature was raised to 90°C and maintained for 0.5h to allow the reaction to proceed. After cooling to 40°C, the pH was adjusted to 7–8 using ammonia water. Subsequently, the mixture was filtered and discharged, followed by a drying process to obtain organosilicon compound particles with a number average molecular weight of 39,529, which were recorded as O2. The water content of O2 was 1500 μg / g, the volume distribution particle size Dv90 was 1.8 μm, the volume distribution particle size Dv50 was 1.2 μm, the volume distribution particle size Dv10 was 0.6 μm, and the specific surface area was 10 m². 2 / g is. Comparative Example 1 The battery cell is manufactured in a manner similar to Example 1, the difference being parameters related to the coating layer of the separator, such as the particle material and M / (H·ρ 유기 ) and specific parameters can be found in Table 1. Test section (1) Test of thermal shrinkage rate of the separator Sample preparation step: The separator prepared above is punched into a sample with a width of 50 mm and a length of 100 mm using a punching machine, and five double samples are placed on an A4 sheet and fixed, and then the A4 sheet containing the samples is placed on a corrugated cardboard with a thickness of 1 mm to 5 mm. Sample test step; A4 paper placed on a corrugated cardboard is placed in a blower dryer, and the temperature of the blower dryer is set to 150℃. Once the temperature reaches the set temperature, it is stabilized for 30 minutes, and then the timer is started. After 1h is reached, the length and width of the separator are measured and the values ​​are labeled as a and b, respectively. Thermal shrinkage rate calculation step: Longitudinal (MD) thermal shrinkage rate = [(100-a) / 100] × 100%, transverse (TD) thermal shrinkage rate = [(50-b) / 50] × 100%, and the average value of 5 double samples is calculated and used as the test result. (2) Battery capacity retention rate test At 25℃, charge to 4.3V with a constant current of 1 / 3C, then charge with a constant voltage of 4.3V until the current becomes 0.05C, leave for 5 minutes, and then discharge to 2.8V with 1 / 3C; the capacity obtained is set as the initial capacity (C0). The discharge capacity (C) of the battery after the 1000th cycle is... 1000 If ) is recorded, the battery capacity retention rate after each cycle is P 1000 =C 1000 / C0*100% is. Table 1 lists the test results of the coating layer according to different parameters in Examples 1 to 12 and Comparative Example 1. turn coating layer 150℃, 1h heat shrinkage rate Capacity retention rate (%) after 1,000 cycles at 25℃ Types of organic materials Mg / m 2 H μm r 유기 g / cm 3 M / (H·p 유기 ) MD(%) TD(%) Example 1 Organosilicon compound particles (O1) 1.53 2.66 1.39 0.41 2.03 1.56 93.9 Example 2 Organosilicon compound particles (O1) 1.53 2.05 1.39 0.54 0.53 0.55 95.2 Example 3 Organosilicon compound particles (O1) 1.53 1.78 1.39 0.62 0.33 0.35 94.5 Example 4 Organosilicon compound particles (O1) 1.53 1.54 1.39 0.71 0.29 0.24 94.1 Example 5 Organosilicon compound particles (O1) 1.53 1.39 1.39 0.79 0.2 0.21 93.4 Example 6 Organosilicon compound particles (O1) 1.85 2.66 1.39 0.5 0.56 0.58 94.6 Example 7 Organosilicon compound particles (O1) 2.40 2.66 1.39 0.65 0.2 0.18 96.1 Example 8 Organosilicon compound particles (O1) 2.77 2.66 1.39 0.75 0.24 0.22 93.8 Example 9 Organosilicon compound particles (O1) 2.95 2.66 1.39 0.80 0.19 0.21 93.6 Example 10 Organosilicon compound particles (O2) 1.53 2.66 0.85 0.68 0.23 0.22 93.3 Example 11 Phenolic resin particles 1.53 2.66 0.93 0.62 0.38 0.35 90.5 Example 12 polyimide particles 1.53 2.66 0.91 0.63 0.41 0.29 90.2 Comparative Example 1 Organosilicon compound particles (O1) 1.02 2.48 1.39 0.30 5 4.3 86.9 As can be seen by comparing the test results of Examples 1 to 12 and Comparative Example 1 according to Table 1, the coating layer contains particulate organic material and the separation membrane If these conditions are met, on the one hand, organic materials within the coating layer can be reasonably deposited, and when the separator is heated, the mutual compression between the organic materials provides a force opposite to the direction of separator shrinkage, thereby reducing the degree of shrinkage of the separator. This reduces the risk of short circuits between the positive and negative electrodes in a battery using this separator, allowing the battery to have good thermal safety performance. On the other hand, while allowing organic materials to be reasonably deposited in the coating layer, more ion transport channels can be formed through the bonding between the organic materials. Furthermore, since the impregnation of the electrolyte into the separator and storage within the separator can be improved through these ion transport channels, it is advantageous for ion transport, thereby improving the cycle performance of the battery. It should be noted that the present application is not limited to the embodiments described above. The embodiments described above are merely examples, and any embodiments having substantially the same configuration as the technical concept and producing the same effect within the scope of the technical solution of the present application are included within the technical scope of the present application. Furthermore, other forms configured by applying various modifications that a person skilled in the art could conceive of to the embodiments without deviating from the essence of the present application, and by combining some of the components of the embodiments, are also included within the scope of the present application. Explanation of the symbols 1-Battery pack, 2-Upper box, 3-Lower box, 4-Battery module, 5-Battery cell, 51-Housing, 52-Electrode assembly, 53-Cover plate.

Claims

Claim 1 A separation membrane comprises: a substrate; and a coating layer installed on at least one side of the substrate and comprising a particulate organic material, wherein the weight of a unit area of ​​a single-sided coating layer is M, the thickness of a single-sided coating layer is H, and the true density of the organic material If so, the separator is M≥1.1, 0.5≤H<3 and 0.8≤ Satisfies ≤2.5, and the unit of M is g / m 2 and the unit of H is μm, and The unit is g / cm 3 Phosphorus, separator. Claim 2 In paragraph 1, 0.5≤ Separator, ≤0.

8. Claim 3 In paragraph 1 or 2, 1.1≤ ≤2.5 and; optionally, 0.8≤ Separator, ≤2.

0. Claim 4 A separator in any one of paragraphs 1 to 3, wherein 0.7 ≤ M ≤ 3.

0. Claim 5 A separator in any one of paragraphs 1 to 4, wherein 0.5 ≤ H ≤ 2.

0. Claim 6 In any one of paragraphs 1 through 5, and; optionally, 0.5≤ Separator, ≤1.

0. Claim 7 A separation membrane according to any one of claims 1 to 6, wherein the mass percentage of the organic material in the coating layer is greater than or equal to 60%; optionally 75% to 95%. Claim 8 In any one of claims 1 to 7, the organic material comprises one or more of organosilicon compound particles, melamine-formaldehyde resin particles, phenol resin particles, polyester particles, polyimide particles, polyamideimide particles, aromatic polyamide particles, polyphenylene sulfide particles, polysulfone particles, polyethersulfone particles, polyetheretherketone particles, and polyaryletherketone particles; optionally, the organic material comprises organosilicon compound particles, forming a separation membrane. Claim 9 In any one of claims 1 to 8, the organic material comprises organosilicon compound particles, the organosilicon compound particles comprise a first polymer, the first polymer comprises a first structural unit, a second structural unit and a third structural unit; the first structural unit has a structure shown in formula (I); Formula (I) wherein R1 comprises a hydrogen atom or one or more of a substituted or unsubstituted C1-C5 alkyl group; optionally, R1 comprises a hydrogen atom or one or more of a substituted or unsubstituted C1-C3 alkyl group; R2 comprises one or more of a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, or a substituted or unsubstituted C1-C20 hydroxyalkyl group; optionally, R2 comprises one or more of a C1-C12 alkyl group, a C3-C12 cycloalkyl group, or a C1-C12 hydroxyalkyl group; and the second structural unit is as shown in Formula (II); Formula (II) wherein R3 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C5 alkyl group; optionally, R3 comprises a hydrogen atom, or one or more of a substituted or unsubstituted C1-C3 alkyl group; and the third structural unit is as shown in Formula (III); In Equation (III), R4 to R 11 Each comprises an independently substituted or unsubstituted C1-C10 alkyl group, or one or more of the structural units shown in Formula (III-1), and R4 to R 11 At least one of them is a structural unit as shown in Equation (III-1); In Equation (III-1), R 12 comprises a hydrogen atom, or one or more of substituted or unsubstituted C1-C5 alkyl groups; optionally, R 12 comprises a hydrogen atom, or one or more of substituted or unsubstituted C1-C3 alkyl groups; R 13 comprises a substituted or unsubstituted C1-C10 alkyl group; optionally, R 13 A separator comprising a substituted or unsubstituted C3-C10 alkyl group. Claim 10 In claim 9, calculated based on the total molar mass of the first structural unit, the second structural unit, and the third structural unit, and assuming the molar content of the first structural unit is a%, 70 ≤ a ≤ 90; optionally, 75 ≤ a ≤ 85; and / or calculated based on the total molar mass of the first structural unit, the second structural unit, and the third structural unit, and assuming the molar content of the second structural unit is b%, 0 <b≤18이고; 선택적으로, 2≤b≤8이며; 및 / 또는상기 제1 구조단위, 상기 제2 구조단위 및 상기 제3 구조단위의 총 몰 질량을 기준으로 계산하고 상기 제3 구조단위의 몰 함량을 c%로 하면, 0<c≤15이고; 선택적으로, 4≤c≤10인, 분리막. Claim 11 In claim 9 or 10, the separation membrane satisfies one or more of the following: (1) 5 ≤ a / b ≤ 10; (2) 6 ≤ a / c ≤ 15; (3) a:b:c is (14~16):(3~4):(1~4). Claim 12 In any one of claims 1 to 11, the organic material comprises organosilicon compound particles, the organosilicon compound particles comprise a second polymer, and the second polymer comprises a structural unit shown in formula (a); In equation (a), R 14 and R 15 Each is independently selected from substituted or unsubstituted C1-C10 alkyl groups, hydroxyl groups, or amino groups; optionally, R 14 and R 15 Each is independently selected from a substituted or unsubstituted C1-C6 alkyl group, a hydroxyl group, or an amino group; optionally, the second polymer comprises one or more of polymethylsiloxane, polydimethylsiloxane, polydiethylsiloxane, polymethylhydroxysiloxane, and polymethylaminosiloxane, forming a separator. Claim 13 A separation membrane according to any one of claims 9 to 12, wherein the number average molecular weight of the organosilicon compound particles is 25,000 to 60,000 and optionally 30,000 to 50,000. Claim 14 A separation membrane according to any one of claims 9 to 13, wherein, when calculated based on the mass of the organosilicon compound particles, the moisture content of the organosilicon compound particles is less than or equal to 3000 μg / g; optionally 700 μg / g to 2500 μg / g. Claim 15 In any one of claims 9 to 14, the volume distribution particle size Dv90 of the organosilicon compound particles satisfies Dv90 ≤ 4.0 μm; optionally, 0.5 μm ≤ Dv90 ≤ 3.0 μm; optionally, the volume distribution particle size Dv50 of the organosilicon compound particles satisfies 1.0 μm ≤ Dv50 ≤ 2.5 μm; optionally, the particle size distribution of the organosilicon compound particles satisfies 0.5 ≤ (D V 90-D V 10) / D V A separator satisfying 50≤1.

5. Claim 16 In any one of claims 9 to 15, the specific surface area of ​​the organosilicon compound particles is 35 m² 2 Less than or equal to / g; optionally 5m 2 / g~30m 2 / g, separator. Claim 17 A separator according to any one of claims 1 to 16, wherein the thickness of the substrate is less than or equal to 12 μm and optionally 3 μm to 8 μm; and / or, the substrate has a porous structure, and the porosity of the substrate is greater than or equal to 20% and optionally 25% to 45%. Claim 18 In any one of claims 1 to 17, the separator comprises: (1) a longitudinal thermal shrinkage rate of the separator at 150°C and 1h that is less than or equal to 3%; (2) a transverse thermal shrinkage rate of the separator at 150°C and 1h that is less than or equal to 2%; (3) an air permeability of the separator that is less than or equal to 200 s / 100 mL, optionally between 150 s / 100 mL and 200 s / 100 mL; and (4) a longitudinal tensile strength of the separator that is 2700 kgf / cm² 2 Greater than or equal to; (5) The transverse tensile strength of the above separation membrane is 2500 kgf / cm 2 A separator that satisfies at least one of being greater than or equal to. Claim 19 A method for manufacturing a separation membrane according to any one of claims 1 to 18, comprising: a step of supplying a substrate; a step of preparing a coating layer slurry by mixing a particulate organic material with a solvent; a step of coating the coating layer slurry on at least one side of the substrate to form a slurry film layer, and drying the film layer to form a coating layer and obtain a separation membrane, wherein the weight of a unit area of ​​the single-sided coating layer is M, the thickness of the single-sided coating layer is H, and the true density of the organic material If so, the above separator is It satisfies, and the unit of M is g / m 2 and the unit of H is μm, and The unit is g / cm 3 Phosphorus, manufacturing method. Claim 20 A secondary battery comprising a separator according to any one of claims 1 to 18 or a separator obtained by the manufacturing method according to claim 19. Claim 21 An electrical device including a secondary battery pursuant to Article 20.

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