Phenolic resin-based organic particles, method for preparing same, separator, secondary battery cell, battery device, and electric device

Abstract

The invention provides phenolic resin type organic particles and a preparation method thereof, an isolating membrane, a secondary battery monomer, a battery device and a power utilization device, the volume distribution particle size Dv50 of the phenolic resin type organic particles is 100nm-800nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin type organic particles is 1.4-3. The phenolic resin organic particles are used in the isolating membrane, so that the secondary battery monomer has high mass energy density, high reliability and good cycle performance.

Description

[0001] This application claims priority to Chinese Patent Application No. 202410946540.2, filed on July 15, 2024, entitled “Phenolic Resin-Based Organic Particles, Preparation Method Thereof, Separating Membrane, Battery Cell, and Electric Device,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to a phenolic resin-based organic particle, a preparation method thereof, a separating membrane, a secondary battery cell, a battery device, and an electric device. BACKGROUND

[0003] With the increasingly wide range of applications of secondary battery cells, people’s demand for the use of secondary battery cells is also increasing, such as higher and higher requirements for energy density, service life, and reliability. Therefore, how to make the secondary battery cell have higher energy density and good cycle stability under the premise of high reliability is a technical problem to be solved at present. SUMMARY

[0004] The present disclosure provides a phenolic resin-based organic particle, a preparation method thereof, a separating membrane, a secondary battery cell, a battery device, and an electric device, the phenolic resin-based organic particle is used in the separating membrane, which can make the secondary battery cell have high mass energy density, high reliability, and good cycle performance.

[0005] In a first aspect, the present disclosure provides a phenolic resin-based organic particle, wherein a volume distribution particle size Dv50 of the phenolic resin-based organic particle is 100 nm-800 nm, and a particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin-based organic particle is 1.4-3.

[0006] The secondary battery cell using the phenolic resin-based organic particle with small density can have higher mass energy density. The volume distribution particle size Dv50 of the phenolic resin-based organic particle is 100 nm-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 is 1.4-3. The phenolic resin-based organic particle satisfying the particle size distribution can be closely arranged. By using the phenolic resin-based organic particle satisfying the above parameters in the separating membrane, the phenolic resin-based organic particle can generate a force to resist the shrinkage of the separating membrane, thereby improving the overall thermal shrinkage of the separating membrane, improving the heat resistance of the separating membrane, and improving the reliability of the secondary battery cell. The phenolic resin-based organic particle satisfying the above parameters used in the separating membrane can also make the separating membrane have good air permeability, thereby also being conducive to improving the cycle performance of the secondary battery cell. Therefore, the phenolic resin-based organic particle of the present disclosure used in the separating membrane can make the secondary battery cell have high mass energy density, high reliability, and good cycle performance.

[0007] In some embodiments, the phenolic resin-based organic particles have a volume distribution particle size Dv50 of 200-600 nm. The phenolic resin-based organic particles having a volume distribution particle size Dv50 within the above range, when used in the separator film, can make the separator film have better heat resistance and air permeability, and make the secondary battery cell have better cycle performance.

[0008] In some embodiments, the phenolic resin-based organic particles have a particle size distribution (Dv90-Dv10) / Dv50 of 1.6-2.7. The phenolic resin-based organic particles having a particle size distribution (Dv90-Dv10) / Dv50 within the above range, when used in the separator film, can make the separator film have better heat resistance and air permeability, and make the secondary battery cell have better cycle performance.

[0009] In some embodiments, the phenolic resin-based organic particles have a volume distribution particle size Dv90 of 800-1800 nm, or 820-1250 nm. The phenolic resin-based organic particles having a volume distribution particle size Dv90 within the above range, when used in the separator film, are beneficial to improving the uniformity of the coating of the separator film.

[0010] In some embodiments, the phenolic resin-based organic particles have a volume distribution particle size Dv10 of 50-200 nm, or 90-185 nm. The phenolic resin-based organic particles having a volume distribution particle size Dv10 within the above range, when used in the separator film, can reduce the risk of hole blocking of the separator film.

[0011] In some embodiments, the phenolic resin-based organic particles have no melting point. The phenolic resin-based organic particles of the present disclosure have no melting point, indicating that the phenolic resin-based organic particles have good heat resistance and thermal stability, thereby better resisting thermal shrinkage of the separator film, improving the heat resistance of the separator film, and improving the reliability of the secondary battery cell.

[0012] In some embodiments, the phenolic resin-based organic particles have no glass transition temperature below 300°C.

[0013] The phenolic resin-based organic particles have no glass transition temperature below 300°C, indicating that the phenolic resin-based organic particles have good heat resistance and thermal stability, thereby better resisting thermal shrinkage of the porous base film, improving the heat resistance of the separator film, and improving the reliability of the secondary battery cell.

[0014] In some embodiments, the phenolic resin-based organic particles are thermosetting resol resin.

[0015] In some embodiments, the phenolic resin-based organic particles have a true density of 1.0 g / cm 3 -1.4 g / cm 3Thus, the secondary battery cell employing the separator film of the present disclosure can have a higher mass energy density.

[0016] In a second aspect, the present disclosure provides a method for preparing phenolic resin-based organic particles, comprising the following steps: providing a resol phenolic resin-based material; heating and curing the resol phenolic resin-based material to obtain a to-be-crushed resol phenolic resin-based material; crushing the to-be-crushed resol phenolic resin-based material to obtain crushed resol phenolic resin-based organic particles; uniformly mixing the crushed resol phenolic resin-based organic particles with a first dispersant and water to obtain a sanding slurry, and then performing sanding treatment and filtration treatment to obtain resol phenolic resin-based organic particles, wherein the first dispersant is a high-molecular dispersant, the resol phenolic resin-based organic particles have a volume distribution particle size Dv50 of 100 nm-800 nm, and the resol phenolic resin-based organic particles have a particle size distribution (Dv90-Dv10) / Dv50 of 1.4-3.

[0017] The preparation method provided by the embodiments of the present disclosure adds a high-molecular dispersant in the sanding treatment process. The high-molecular dispersant helps to reduce the agglomeration of particles and maintain the uniform distribution of particles by reducing the interaction between particles, so that resol phenolic resin-based organic particles with small particle size and narrow particle size distribution can be prepared. In addition, the introduction of the high-molecular dispersant can increase the solid content of the sanding slurry while reducing the viscosity of the sanding slurry, thereby improving the sanding efficiency, allowing the resol phenolic resin-based organic particles to be tightly packed, and further improving the heat resistance of the separator film.

[0018] In some embodiments, the first dispersant includes one or more of a polyether dispersant, a polyacrylic acid dispersant, a polycarboxylate dispersant, polyvinylpyrrolidone, and polyethylene glycol. The type of first dispersant is within the above range, which can further optimize the solid content and viscosity of the sanding slurry, be conducive to the preparation of resol phenolic resin-based organic particles with small particle size and narrow particle size distribution, be conducive to the tight packing of the resol phenolic resin-based organic particles, and further allow the separator film to have better heat resistance and air permeability, so that the secondary battery cell has better cycle performance.

[0019] In some embodiments, the mass of the first dispersant is 0.01%-2% of the mass of the crushed resol phenolic resin-based organic particles. The content of the first dispersant is within the above range, which can further optimize the solid content and viscosity of the sanding slurry, be conducive to the preparation of resol phenolic resin-based organic particles with small particle size and narrow particle size distribution, be conducive to the tight packing of the resol phenolic resin-based organic particles, and further allow the separator film to have better heat resistance and air permeability, so that the secondary battery cell has better cycle performance.

[0020] In a third aspect, the present disclosure provides another method for preparing phenolic resin-based organic particles, comprising the following steps: providing a foaming agent and a resol phenolic resin-based material; uniformly mixing the foaming agent and the resol phenolic resin-based material, and then performing heat curing to obtain a to-be-crushed phenolic resin-based material; performing crushing treatment on the to-be-crushed phenolic resin-based material to obtain crushed phenolic resin-based organic particles; and performing sanding treatment on the crushed phenolic resin-based organic particles to obtain phenolic resin-based organic particles, wherein the volume distribution particle size Dv50 of the phenolic resin-based organic particles is 100 nm-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin-based organic particles is 1.4-3.

[0021] The foaming agent is added during the heat curing of the resol phenolic resin-based material. During the heat curing, the foaming agent can produce gas by decomposition or volatilization, so that the resol phenolic resin-based material expands to form a foam, changes the structure and properties of the resol phenolic resin-based material, and the gas can diffuse through the film wall of the resol phenolic resin-based material to inhibit the expansion of the cured crosslinked network of the resol phenolic resin-based material. Thus, the resol phenolic resin-based material can be easily crushed and sanded to obtain phenolic resin-based organic particles with small particle size and narrow particle size distribution. Therefore, the preparation method provided by the embodiments of the present disclosure can efficiently obtain phenolic resin-based organic particles with small particle size and narrow particle size distribution.

[0022] In some embodiments, the mass of the foaming agent is 1%-20% of the mass of the resol phenolic resin-based material. An appropriate amount of foaming agent is beneficial to obtain phenolic resin-based organic particles with small particle size and narrow particle size distribution.

[0023] In some embodiments, the foaming agent comprises an organic foaming agent and / or an inorganic foaming agent.

[0024] In some embodiments, a second dispersant is further added when the crushed phenolic resin-based organic particles are subjected to sanding treatment.

[0025] In some embodiments, the second dispersant comprises one or more of a polyether dispersant, a polyacrylic acid dispersant, a polycarboxylate dispersant, polyvinylpyrrolidone, and polyethylene glycol. The type of the second dispersant is within the above range, which can optimize the solid content and viscosity of the sanding slurry, thereby being beneficial to the preparation of phenolic resin-based organic particles with small particle size and narrow particle size distribution, and being beneficial to the close packing of the phenolic resin-based organic particles, and further enabling the isolation film to have better heat resistance and air permeability, and enabling the secondary battery cell to have better cycle performance.

[0026] In some embodiments, the second dispersant has a mass content of 0.01%-2% of the mass of the broken phenolic resin-based organic particles. The content of the second dispersant in the above range can optimize the solid content and viscosity of the sanding slurry, thereby facilitating the preparation of phenolic resin-based organic particles with small particle size and narrow particle size distribution, and facilitating the close packing of the phenolic resin-based organic particles, and thus the separator film can have better heat resistance and air permeability, and the secondary battery cell can have better cycle performance.

[0027] In a fourth aspect, the present disclosure provides a separator film, comprising a porous base film and a coating layer on at least one side of the porous base film, wherein the coating layer comprises the phenolic resin-based organic particles of the first aspect, or the phenolic resin-based organic particles prepared by the method of the second aspect or the third aspect.

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

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

[0030] In some embodiments, the areal density of the coating layer is 0.45 g / m 2 -4.5 g / m 2 .

[0031] In some embodiments, the ratio of the volume distribution particle size Dv50 of the phenolic resin-based organic particles to the average pore size of the porous base film is greater than or equal to 1.5.

[0032] In some embodiments, the longitudinal heat shrinkage of the separator film is less than or equal to 2% when heated at 130°C for 1 h.

[0033] In some embodiments, the transverse heat shrinkage of the separator film is less than or equal to 2% when heated at 130°C for 1 h.

[0034] In some embodiments, the air permeability value of the separator film is 160 s / 100 mL-230 s / 100 mL.

[0035] In a fifth aspect, the present disclosure provides a secondary battery cell, comprising a positive electrode sheet, a negative electrode sheet, and the separator film of the fourth aspect of the present disclosure, wherein the separator film is disposed between the positive electrode sheet and the negative electrode sheet.

[0036] In a sixth aspect, the present disclosure provides a battery device, comprising a plurality of secondary battery cells of the fifth aspect of the present disclosure.

[0037] In a seventh aspect, the present disclosure provides an electric device, comprising the secondary battery cell of the fifth aspect of the present disclosure or the battery device of the sixth aspect of the present disclosure. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on the drawings without any creative effort.

[0039] Figure 1 A schematic diagram of a secondary battery cell provided in some embodiments of this disclosure is shown.

[0040] Figure 2 A schematic diagram of an electrical device provided in some embodiments of this disclosure is shown.

[0041] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0042] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the phenolic resin organic particles, their preparation methods, separators, secondary battery cells, battery devices, and electrical devices of this disclosure. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for a full understanding of this disclosure by those skilled in the art and are not intended to limit the subject matter of the claims.

[0043] The ranges disclosed herein are defined by their lower and upper endpoints, given that a range is defined by selecting a lower endpoint and an upper endpoint, the selected lower and upper endpoints define the boundaries of the particular range. Ranges defined by endpoints can be either inclusive or exclusive of the endpoints, and can be arbitrarily combined, i.e., any lower endpoint can be combined with any upper endpoint to form a range. For example, if ranges of 60-120 and 80-110 are listed, it is understood that ranges of 60-110 and 80-120 are also contemplated. Also, if minimum range values of 1 and 2 are listed, and if maximum range values of 3, 4, and 5 are listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In the present disclosure, unless otherwise stated, a numerical range "a-b" indicates a shorthand way of describing all of the individual real combinations that fall between "a" and "b", where "a" and "b" are both real numbers. For example, the numerical range "0-5" indicates that all of the real numbers between "0" and "5" have been listed herein, and "0-5" is merely a shorthand way of describing these numerical combinations. In addition, when a parameter is stated to be an integer ≥ 2, it is equivalent to disclose that the parameter is, for example, integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0044] Unless otherwise specified, all embodiments and optional embodiments of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0045] Unless otherwise specified, all technical features and optional technical features of the present disclosure can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present disclosure.

[0046] Unless otherwise specified, all steps of the present disclosure can be performed in sequence or randomly, and preferably in sequence. For example, the method comprises steps (a) and (b), which means that the method can comprise steps (a) and (b) in sequence, or steps (b) and (a) in sequence. For example, the method also comprises step (c), which means that step (c) can be added to the method in any order, for example, the method can comprise steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0047] Unless otherwise specified, in the present disclosure, the terms "first", "second", etc. are used to distinguish different objects, and are not used to describe a particular order or primary and secondary relationship.

[0048] In the present disclosure, the terms "a plurality of", "a plurality of" refer to two or more.

[0049] In the description of the embodiments of the present disclosure, if there is no special indication, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature can be "above", "over" and "on" the second feature, which can be that the first feature is directly above or obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature can be "below", "under" and "under" the second feature, which can be that the first feature is directly below or obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0050] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25°C.

[0051] The secondary battery cell mentioned in the embodiments of the present disclosure can realize the function of charging and discharging independently, and can continue to be used by activating the active material through charging after discharging. The secondary battery cell can be in the shape of a cylinder, a cuboid or other shapes, which are not limited in the embodiments of the present disclosure. For example, Figure 1 is a cuboid structure of a secondary battery cell 5 as an example.

[0052] The secondary battery cell provided by the embodiments of the present disclosure can include but is not limited to lithium battery cells, sodium battery cells, such as lithium ion battery cells, sodium ion battery cells, lithium metal battery cells, sodium metal battery cells, etc.

[0053] The secondary battery cell provided by the embodiments of the present disclosure includes an electrode assembly. The electrode assembly can be a winding structure or a stacking structure, which is not limited in the embodiments of the present disclosure. The secondary battery cell further includes an outer package, which can be used to package the electrode assembly. The outer package can be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer package can also be a soft package, such as a bag-type soft package. The material of the soft package can be plastic, such as one or more of aluminum-plastic film, polypropylene, polybutylene terephthalate (PBT) and polybutylene succinate (PBS).

[0054] The battery apparatus mentioned in the embodiments of the present disclosure can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of secondary battery cells connected in series, in parallel or in a hybrid manner through a busbar component.

[0055] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of secondary battery cells.

[0056] As an example, the battery cell assembly can be a battery module, which is formed by arranging and fixing a plurality of secondary battery cells into one independent module. As an example, the battery module can be formed by bundling a plurality of secondary battery cells with a cable tie.

[0057] In some embodiments, the battery device can be a battery pack, which includes a case and one or more battery cell assemblies accommodated in the case.

[0058] As an example, the battery cell assembly can be a battery module, which can be accommodated in the case by fixing the battery module in the case.

[0059] As an example, the battery cell assembly can also be accommodated in the case by directly fixing a plurality of secondary battery cells in the case.

[0060] As an example, the case can include a first case and a second case. The first case and the second case are fastened so that an enclosed space is formed inside the case to accommodate the battery cell assembly. Here, the enclosed means covered or closed, which can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0061] As an example, the case can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected to the frame, respectively, so that an enclosed space is formed inside the case to accommodate the battery cell assembly.

[0062] In some embodiments, the case can be part of the chassis structure of a vehicle. For example, part of the case can be at least part of the floor of the vehicle, or part of the case can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0063] The technical solutions described in the embodiments of the present disclosure are applicable to various electric devices using secondary battery cells and battery devices, such as mobile devices (e.g., mobile phones, tablet computers, notebook computers, etc.), electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc. The secondary battery cells and the battery devices are used to store or provide electric energy.

[0064] Figure 2 is a schematic diagram of an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0065] In the context of the present disclosure, the "phenolic resin-based organic particles" mainly play a role in improving heat resistance in the coating layer of the separator film, and almost have no adhesion.

[0066] The separator film is an important component for supporting the secondary battery cell to complete the charge-discharge electrochemical process. The commonly used separator film is mostly polyolefin film. However, the heat resistance of the polyolefin film is poor, and the polyolefin film is easy to soften or melt at high temperature, which may cause short circuit of the secondary battery cell. In order to improve the heat resistance of the separator film, a coating layer is usually coated on the separator film to improve the heat resistance of the separator film. Inorganic particles such as boehmite and aluminum oxide are currently commonly used heat-resistant fillers. However, the density of such heat-resistant fillers is large, and the mass is large under the same packing volume, which affects the energy density of the secondary battery cell.

[0067] Therefore, the phenolic resin-based organic particles of the present disclosure are used in the separator film, and the secondary battery cell has high mass energy density, high reliability and good cycle performance.

[0068] The volume distribution particle size Dv50 of the phenolic resin-based organic particles of the present disclosure is 100 nm-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin-based organic particles is 1.4-3.

[0069] The density of the phenolic resin-based organic particles is small, and the secondary battery cell using the same can have higher mass energy density.

[0070] The volume distribution particle size Dv50 of the phenolic resin-based organic particles is 100 nm-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 is 1.4-3. The phenolic resin-based organic particles satisfying the particle size distribution can be closely arranged. By using the phenolic resin-based organic particles satisfying the above parameters in the separator film, the phenolic resin-based organic particles can generate a force to resist the shrinkage of the separator film, thereby improving the overall thermal shrinkage of the separator film, improving the heat resistance of the separator film, and improving the reliability of the secondary battery cell. The phenolic resin-based organic particles satisfying the above parameters are used in the separator film, which can also make the separator film have good air permeability, thereby also being beneficial to improve the cycle performance of the secondary battery cell.

[0071] Therefore, the phenolic resin-based organic particles of the present disclosure are used in the separator film, and the secondary battery cell has high mass energy density, high reliability and good cycle performance.

[0072] The particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin-based organic particles is 1.4-3, for example, can be 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, or a range composed of any of the above values.

[0073] Optionally, the phenolic resin-based organic particles have a particle size distribution (Dv90-Dv10) / Dv50 of 1.4-2.8, 1.5-2.8, 1.6-2.8, 1.7-2.8, 1.8-2.8, 1.9-2.8, 1.6-2.7, 1.7-2.7, 1.8-2.7, 1.9-2.7, 1.6-2.6, 1.7-2.6, 1.8-2.6, 1.9-2.6, 1.6-2.5, 1.7-2.5, 1.8-2.5, 1.9-2.5.

[0074] The phenolic resin-based organic particles have a particle size distribution (Dv90-Dv10) / Dv50 in the above range, which can make the separator film have better heat resistance and air permeability, and make the secondary battery monomer have better cycle performance.

[0075] The phenolic resin-based organic particles have a volume distribution particle size Dv50 of 100-800 nm, for example, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, or a range consisting of any of the above values.

[0076] Optionally, the phenolic resin-based organic particles have a volume distribution particle size Dv50 of 200-600 nm, 200-550 nm, 200-500 nm, 200-450 nm, 250-600 nm, 200-600 nm, 250-500 nm, 250-450 nm.

[0077] The phenolic resin-based organic particles have a volume distribution particle size Dv50 in the above range, which can make the separator film have better heat resistance and air permeability, and make the secondary battery monomer have better cycle performance.

[0078] In some embodiments, the phenolic resin-based organic particles have a volume distribution particle size Dv90 of 800-1800 nm, for example, 800 nm, 850 nm, 900 nm, 950 nm, 1000 nm, 1050 nm, 1100 nm, 1150 nm, 1200 nm, 1250 nm, 1300 nm, 1350 nm, 1400 nm, 1450 nm, 1500 nm, 1550 nm, 1600 nm, 1650 nm, 1700 nm, 1750 nm, 1800 nm, or a range consisting of any of the above values.

[0079] The volume distribution particle size Dv90 of the phenolic resin organic particles is within the above range, which is used in the isolation film and is beneficial to improve the uniformity of the coating of the isolation film.

[0080] Alternatively, the volume distribution particle size Dv90 of the phenolic resin organic particles can be 800 nm-1600 nm, 800 nm-1500 nm, 800 nm-1400 nm, 800 nm-1300 nm, 800 nm-1250 nm, 800 nm-1100 nm, 800 nm-1050 nm, 800 nm-1000 nm, 800 nm-950 nm, 800 nm-900 nm.

[0081] In some embodiments, the volume distribution particle size Dv10 of the phenolic resin organic particles can be 50 nm-200 nm, for example, can be 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, 125 nm, 130 nm, 135 nm, 140 nm, 145 nm, 150 nm, 155 nm, 160 nm, 170 nm, 180 nm, 190 nm, 200 nm, or a range consisting of any of the above values.

[0082] The volume distribution particle size Dv10 of the phenolic resin organic particles is within the above range, which is used in the isolation film and can reduce the risk of hole blocking problem of the isolation film.

[0083] Alternatively, the volume distribution particle size Dv10 of the phenolic resin organic particles can be 70 nm-200 nm, 90 nm-200 nm, 100 nm-200 nm, 105 nm-200 nm, 70 nm-185 nm, 90 nm-185 nm, 100 nm-185 nm, 105 nm-185 nm, 70 nm-170 nm, 90 nm-170 nm, 100 nm-170 nm, 105 nm-170 nm, 70 nm-160 nm, 90 nm-160 nm, 100 nm-160 nm, 105 nm-160 nm.

[0084] Dv10, Dv50, Dv90 respectively represent the particle size corresponding to the cumulative volume distribution percentage of 10%, 50%, and 90% of the material, which can be tested by a laser particle size analyzer according to GB / T 19077-2016. During the test, a clean small beaker is taken, 1 g of the sample to be tested is added, 20 ml of deionized water is added, and ultrasonic treatment is performed at 53 KHz / 120 W for 5 min to ensure that the sample is completely dispersed; the laser particle size analyzer is turned on, the light path system is cleaned, and the background is automatically tested; the sample solution after ultrasonic treatment is stirred to make it uniformly dispersed, and then placed in the sample cell according to the requirements, and the particle size is measured. The testing instrument can be a MasterSizer 3000 laser particle size analyzer.

[0085] In some embodiments, the phenolic resin-based organic particles can have a true density of 1.0 g / cm3 3 -1.4 g / cm3 3 .

[0086] At present, the true density of inorganic particles such as boehmite and alumina is usually 2.5 g / cm3 3 -3.5 g / cm3 3 The true density of the phenolic resin-based organic particles of the present disclosure is small, so that the secondary battery cell using the separator film of the present disclosure has a higher mass energy density.

[0087] The phenolic resin-based organic particles of the present disclosure are neither soluble in water nor in organic solvents such as tetrahydrofuran (THF), dichloromethane (DCM), dimethylformamide (DMF), trichlorobenzene (TCB), and chloroform at 25°C, i.e., they are insoluble in the mobile phase for gel permeation chromatography testing, and the molecular weight of the phenolic resin-based organic particles cannot be tested by gel permeation chromatography.

[0088] In some embodiments, the phenolic resin-based organic particles are thermosetting resol.

[0089] In some embodiments, the phenolic resin-based organic particles have no melting point.

[0090] The phenolic resin-based organic particles of the present disclosure have no melting point, indicating that the phenolic resin-based organic particles have good heat resistance and thermal stability, so that they can better resist the thermal shrinkage of the separator film, improve the heat resistance of the separator film, and improve the reliability of the secondary battery cell.

[0091] Melting point can be tested as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of a differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The DSC curve is used to determine whether phenolic resin organic particles have a melting point below 300℃. Phenolic resin organic particles having no melting point means that the DSC curve of the phenolic resin organic particles does not show a melting peak.

[0092] In some embodiments, phenolic resin organic particles have no glass transition temperature below 300°C.

[0093] Phenolic resin organic particles have no glass transition temperature below 300℃, indicating that they have good heat resistance and thermal stability. This allows them to better resist the thermal shrinkage of porous base films, improve the heat resistance of separators, and enhance the reliability of secondary battery cells.

[0094] Glass transition temperature T g The test can be performed as follows: Take an appropriate amount of sample (e.g., 5mg-15mg) and place it in the crucible of the differential scanning calorimeter (DSC), level it, and cover the crucible. Parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: heat from 25℃ to 200℃ at a heating rate of 10℃ / min, hold for 5min to eliminate thermal history, then cool from 200℃ to -40℃ at a cooling rate of 10℃ / min, and then heat to 300℃ at a heating rate of 10℃ / min. The DSC curve can be used to determine whether phenolic resin organic particles have a glass transition temperature T below 300℃. g .

[0095] Glass transition temperature T g It refers to the transition temperature from the glassy state to the elastic state, which shows a step-like change on the DSC curve.

[0096] Phenolic resin organic particles have no glass transition temperature T below 300℃. g This means that the DSC curve of phenolic resin organic particles does not show a step-like change in the range below 300℃.

[0097] Currently, the organic resin obtained by heating and curing usually has the problem of large particle size, and needs to be first crushed into nano-level powder for application in the separator of the secondary battery cell. The existing process is mainly to crush the large-size organic resin obtained by heating and curing into nano-level powder by physical or chemical methods, for example, by airflow crushing, ultrasonic crushing and the like. However, the crushing method has the problems of low crushing efficiency, high energy consumption and wide particle size distribution.

[0098] The separator according to the embodiments of the present disclosure contains phenolic resin organic particles, and the size of the phenolic resin organic particles needs to reach the nano level, which is extremely complex in processing, and the particles obtained by the conventional processing technology also have the problem of wide particle size distribution.

[0099] Based on this, the embodiments of the present disclosure also provide two preparation methods of the phenolic resin organic particles with small particle size and narrow particle size distribution, which can prepare the phenolic resin organic particles provided by the embodiments of the present disclosure.

[0100] [The first preparation method]

[0101] The first preparation method of the phenolic resin organic particles includes the following steps: providing a resol resin material; heating and curing the resol resin material to obtain a to-be-crushed resol resin material; crushing the to-be-crushed resol resin material to obtain crushed resol resin organic particles; uniformly mixing the crushed resol resin organic particles with a first dispersant and water to obtain a sanding slurry, and then performing sanding treatment and filtration treatment to obtain the phenolic resin organic particles. The first dispersant is a high-molecular dispersant. The volume distribution particle size Dv50 of the phenolic resin organic particles is 100 nm-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin organic particles is 1.4-3.

[0102] The nanocrystallization process of the to-be-crushed resol resin material has certain difficulties. The sanding treatment significantly reduces the size of the resol resin material, and the interaction between the particles is enhanced after the size reduction. The nano particles have a large specific surface area and a high surface activity, which may lead to more complex interaction between the particles, thereby increasing the viscosity of the sanding slurry. In addition, the particles may also aggregate to form larger agglomerates during the nanocrystallization process, which also increases the viscosity of the sanding slurry and reduces the solid content of the sanding slurry. When the solid content of the sanding slurry is too low, the solid content of the separator coating slurry prepared therefrom is low, the viscosity is high, and through holes are easily generated during the drying process of the coating slurry, which may lead to the accumulation of the phenolic resin organic particles and reduce the heat resistance of the separator. The nanocrystallization difficulty of the sanding treatment can be reduced to a certain extent by increasing the amount of sanding medium or reducing the initial solid content of the sanding slurry, but the sanding efficiency is low.

[0103] The preparation method provided by the embodiments of the present disclosure adds a high-molecular dispersant in the sand milling process. The high-molecular dispersant helps to reduce the agglomeration of particles and maintain the uniform distribution of particles by reducing the interaction between particles, so that phenolic resin organic particles with small particle size and narrow particle size distribution can be prepared. In addition, the introduction of the high-molecular dispersant can increase the solid content of the sand milling slurry while reducing the viscosity of the sand milling slurry, thereby improving the sand milling efficiency and enabling the phenolic resin organic particles to be closely packed, and further improving the heat resistance of the isolation film.

[0104] In some embodiments, the first dispersant can include one or more of a polyether dispersant, a polyacrylic dispersant, a polycarboxylate dispersant, polyvinylpyrrolidone, and polyethylene glycol.

[0105] The polyether dispersant refers to a general term of polyether and derivatives thereof that can play a role of a dispersant.

[0106] The polyacrylic dispersant refers to a general term of polyacrylic acid and derivatives thereof that can play a role of a dispersant.

[0107] Optionally, the polyether dispersant can include polyoxyethylene ether.

[0108] Optionally, the polyacrylic dispersant can include one or both of polyacrylic acid and polymethacrylic acid.

[0109] Optionally, the polycarboxylate dispersant can include one or both of polyacrylic acid sodium and polymethacrylic acid sodium.

[0110] The type of the first dispersant is within the above range, which can further optimize the solid content and viscosity of the sand milling slurry, is conducive to the preparation of phenolic resin organic particles with small particle size and narrow particle size distribution, is conducive to the close packing of the phenolic resin organic particles, and further enables the isolation film to have better heat resistance and air permeability, and enables the secondary battery monomer to have better cycle performance.

[0111] In some embodiments, the mass of the first dispersant can be 0.01%-2% of the mass of the broken phenolic resin organic particles, for example, can be 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or a range composed of any of the above values.

[0112] The content of the first dispersant in the above range can further optimize the solid content and viscosity of the sanding slurry, is conducive to the preparation of phenolic resin organic particles with small particle size and narrow particle size distribution, and is also conducive to the close packing of the phenolic resin organic particles, thereby enabling the isolation film to have better heat resistance and air permeability, and enabling the secondary battery monomer to have better cycle performance.

[0113] Optionally, the mass of the first dispersant can be 0.2%-2%, 0.4%-2%, 0.6%-2%, 0.8%-2%, 0.2%-1.6%, 0.4%-1.6%, 0.6%-1.6%, or 0.8%-1.6% of the mass of the broken phenolic resin organic particles.

[0114] In some embodiments, the breaking treatment can employ an air jet mill, a vibration mill, a mechanical crusher, an ultrasonic crusher, a ball mill, etc.

[0115] In some embodiments, the breaking treatment can include a coarse breaking treatment and a re-breaking treatment.

[0116] In some embodiments, the phenolic resin material to be broken is subjected to a breaking treatment, and the volume distribution particle size of the broken phenolic resin organic particles obtained is below 20 μm.

[0117] In some embodiments, the sanding treatment can employ a sanding machine.

[0118] In some embodiments, the rotation speed of the sanding treatment can be 500 rpm-2000 rpm, for example, can be 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, 1900 rpm, 2000 rpm, or a range formed by any of the above values.

[0119] A higher rotation speed is conducive to obtaining phenolic resin organic particles with smaller particle size and narrower particle size distribution.

[0120] In some embodiments, the temperature of the sanding treatment can be 20°C-30°C.

[0121] In some embodiments, the sanding medium can include glass beads, zirconia balls.

[0122] In some embodiments, the diameter of the sanding medium can be 0.1 mm-2 mm, and can optionally be 0.4 mm-1.5 mm. Smaller sanding medium is conducive to obtaining phenolic resin organic particles with smaller particle size and narrower particle size distribution.

[0123] In some embodiments, the sanding medium filling rate can be between 60% and 85%. In this way, the sanding medium can be in sufficient contact with the phenolic resin organic particles, improving the sanding effect and facilitating the obtaining of phenolic resin organic particles with smaller particle size and narrower particle size distribution.

[0124] In some embodiments, the preparation method further comprises a sieving step and a magnetic field removing step after the sanding step.

[0125] The phenolic resin organic particles are obtained by heating and curing the resol phenolic resin material, and thus can have good heat resistance.

[0126] In some embodiments, the heating and curing can be one-step heating and curing or two-step heating and curing.

[0127] Alternatively, the heating and curing can be two-step heating and curing. In this way, phenolic resin organic particles with better heat resistance can be obtained.

[0128] In some embodiments, the heating and curing can be one-step heating and curing, and the temperature of the one-step heating and curing can be 185-280°C, for example, 185°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, or a range consisting of any of the above values.

[0129] Alternatively, the temperature of the one-step heating and curing can be 200-280°C, 210-280°C, 220-280°C, 200-270°C, 210-270°C, 220-270°C.

[0130] Alternatively, the time of the one-step heating and curing can be 3-8h, for example, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, or a range consisting of any of the above values. Alternatively, the time of the one-step heating and curing can be 4-8h.

[0131] In some embodiments, the heating and curing can be two-step heating and curing, the temperature of the first-step heating and curing can be 90-180°C, and the temperature of the second-step heating and curing can be 190-290°C.

[0132] The two-step heating and curing process can make the resol phenolic resin material more fully cured, and thus the phenolic resin organic particles can have better heat resistance and oxidation resistance.

[0133] The temperature of the first heating and curing step can be in the range of 90°C to 180°C, such as 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, or any range derivable therein. Alternatively, the temperature of the first heating and curing step can be in the range of 90°C to 160°C, 100°C to 160°C, 110°C to 160°C, 90°C to 150°C, 100°C to 150°C, 110°C to 150°C.

[0134] The temperature of the first heating and curing step in the above range is also beneficial to eliminate small molecule groups and easily oxidized groups, so that the obtained phenolic resin-based organic particles have better oxidation resistance.

[0135] The temperature of the second heating and curing step can be in the range of 190°C to 290°C, such as 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, or any range derivable therein. Alternatively, the temperature of the second heating and curing step can be in the range of 210°C to 290°C, 210°C to 280°C, 210°C to 270°C.

[0136] The temperature of the second heating and curing step in the above range is also beneficial to eliminate small molecule groups and easily oxidized groups, so that the obtained phenolic resin-based organic particles have better oxidation resistance.

[0137] Alternatively, the time of the first heating and curing step can be in the range of 1h to 5h, such as 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, or any range derivable therein.

[0138] Alternatively, the time of the second heating and curing step can be in the range of 1h to 6h, such as 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, 5.5h, 6h, or any range derivable therein.

[0139] The time of the two heating and curing steps in the above range can improve the heat resistance and oxidation resistance of the phenolic resin-based organic particles.

[0140] In some embodiments, the atmosphere for heat curing can be an oxygen-containing atmosphere or an inert atmosphere.

[0141] The heat curing under the oxygen-containing atmosphere can make the phenolic resin-based organic particles have better oxidation resistance. The curing in the oxygen-containing atmosphere can make the easily-oxidized groups of the resol-based material be oxidized in advance, at which time the phenol structure will be oxidized into a benzoquinone structure, and the benzoquinone structure is not easy to be oxidized, thereby further improving the oxidation resistance of the phenolic resin-based organic particles.

[0142] The oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the inert gas can include, but is not limited to, one or more of nitrogen, argon, and helium.

[0143] Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5% to 50%. More optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 10% to 30%.

[0144] In some embodiments, the atmosphere for heat curing can be an air atmosphere. Thus, the cost can be reduced.

[0145] The resol-based material can be commercially available or synthesized according to a method known in the art. In some embodiments, the method for preparing the resol-based material includes the following steps: reacting a phenolic compound and an aldehyde compound under catalysis of an alkaline substance to obtain the resol-based material.

[0146] Optionally, the alkaline substance can include one or more of ammonia, NaOH, and Na2CO3.

[0147] Optionally, the phenolic compound can include one or more of phenol, p-dihydroxybenzene, m-dihydroxybenzene, o-dihydroxybenzene, cresol, and cardanol.

[0148] Optionally, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propyl aldehyde, n-butyl aldehyde, isobutyl aldehyde, glyoxal, and furfural.

[0149] [Second preparation method]

[0150] The second preparation method of the phenolic resin-based organic particles includes the following steps: providing a foaming agent and a resol-based material; uniformly mixing the foaming agent and the resol-based material, and then performing heat curing to obtain a to-be-crushed resol-based material; performing crushing treatment on the to-be-crushed resol-based material to obtain crushed phenolic resin-based organic particles; and performing sanding treatment on the crushed phenolic resin-based organic particles to obtain the phenolic resin-based organic particles. The volume distribution particle size Dv50 of the phenolic resin-based organic particles is 100 nm to 800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin-based organic particles is 1.4 to 3.

[0151] The foaming agent is added in the heating and curing process of the resol resin material. In the heating and curing process, the foaming agent can produce gas by decomposition or volatilization, so that the resol resin material expands to form a foam, changes the structure and properties of the resol resin material, and the gas can diffuse through the film wall of the resol resin material to inhibit the expansion of the curing cross-linked network of the resol resin material. Thus, the resol resin material can be easily processed by crushing and sanding to obtain resol resin organic particles with small particle size and narrow particle size distribution. Therefore, the preparation method provided by the embodiments of the present disclosure can efficiently obtain resol resin organic particles with small particle size and narrow particle size distribution.

[0152] In addition, the preparation method provided by the embodiments of the present disclosure has simple process and does not need complex operation, and therefore has low production cost.

[0153] In some embodiments, the mass of the foaming agent can be 1%-20% of the mass of the resol resin material, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or a range consisting of any of the above values.

[0154] Alternatively, the mass of the foaming agent can be 2%-20%, 2%-18%, 2%-16%, 2%-14%, 2%-12% of the mass of the resol resin material.

[0155] An appropriate amount of foaming agent is beneficial to obtain resol resin organic particles with small particle size and narrow particle size distribution.

[0156] The foaming agent can include a physical foaming agent and / or a chemical foaming agent. The physical foaming agent does not undergo chemical changes during use, and relies on the change of physical state to achieve foaming. The chemical foaming agent refers to a substance that produces gas through chemical changes during foaming and then foams.

[0157] In some embodiments, the foaming agent can include an organic foaming agent and / or an inorganic foaming agent.

[0158] Alternatively, the foaming agent includes an inorganic foaming agent. The inorganic foaming agent is relatively cheaper than the organic foaming agent, and the gas produced has stronger permeability and is more easily diffused through the film wall, so that the cured resol resin is more easily processed by crushing and sanding.

[0159] Alternatively, the inorganic foaming agent can include one or more of ammonium carbonate, ammonium bicarbonate, sodium bicarbonate, potassium bicarbonate, and sodium carbonate.

[0160] Optionally, the organic blowing agent can include one or more of a low-boiling aliphatic hydrocarbon, a low-boiling halogenated aliphatic hydrocarbon, an azo compound, a hydrazine compound, a nitroso compound.

[0161] Optionally, the aliphatic hydrocarbon can include one or more of n-pentane, isopentane, cyclopentane, hexane, isohexane, propane, butane.

[0162] Optionally, the halogenated aliphatic hydrocarbon can include one or more of dichloromethane, 1-chloro-3,3,3-trifluoropropene, freon.

[0163] Optionally, the azo compound can include one or more of azodicarbonamide, azobisisobutyronitrile, isopropyl azodicarboxylate, diethyl azodicarboxylate, dimethyl azobisobutyrate.

[0164] Optionally, the hydrazine compound can include one or more of 4,4'-oxydihydrazide diphenyl ether, p-toluenesulfonyl hydrazide, 3,3'-dihydrazide diphenyl sulfone, 4,4'-dihydrazide benzene disulfonic acid, 1,3-benzenedisulfonyl hydrazide, 1,4-benzenedisulfonyl hydrazide.

[0165] Optionally, the nitroso compound can include N,N-dinitrosopentamethylenetetramine.

[0166] In some embodiments, the crushing treatment can employ an air jet mill, a vibration mill, a mechanical crusher, an ultrasonic crusher, a ball mill, etc.

[0167] In some embodiments, the sand milling treatment can employ a sand mill.

[0168] In some embodiments, the sand milling treatment can have a rotation speed of 500 rpm-2000 rpm, for example, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, 1600 rpm, 1700 rpm, 1800 rpm, 1900 rpm, 2000 rpm, or a range formed by any of the above values.

[0169] In some embodiments, the sand milling treatment can have a temperature of 20℃-30℃.

[0170] In some embodiments, the sand milling medium can include glass beads, zirconia balls.

[0171] In some embodiments, the sand milling medium can have a diameter of 0.1 mm-2 mm, optionally 0.4 mm-1.5 mm. Smaller sand milling medium is conducive to obtaining phenolic resin-based organic particles with smaller particle size and narrower particle size distribution.

[0172] In some embodiments, the sanding medium filling rate can be between 60% and 85%. In this way, the sanding medium can be in sufficient contact with the phenolic resin organic particles, improving the sanding treatment effect, and facilitating the obtaining of phenolic resin organic particles with smaller particle size and narrower particle size distribution.

[0173] In some embodiments, a second dispersant is also added when the broken phenolic resin organic particles are subjected to sanding treatment. In this way, it is beneficial to obtain phenolic resin organic particles with smaller particle size and narrower particle size distribution.

[0174] Alternatively, the second dispersant can include a high molecular dispersant.

[0175] Alternatively, the second dispersant can include one or more of a polyether dispersant, a polyacrylic acid dispersant, a polycarboxylate dispersant, polyvinylpyrrolidone, and polyethylene glycol. The polyether dispersant refers to a general term for polyether and its derivatives that can function as a dispersant. The polyacrylic acid dispersant refers to a general term for polyacrylic acid and its derivatives that can function as a dispersant. Alternatively, the polyether dispersant can include polyoxyethylene ether. Alternatively, the polyacrylic acid dispersant can include one or both of polyacrylic acid and polymethacrylic acid. Alternatively, the polycarboxylate dispersant can include one or both of polyacrylic acid sodium and polymethacrylic acid sodium.

[0176] The type of second dispersant can be within the above range, which can optimize the solid content and viscosity of the sanding slurry, thereby facilitating the preparation of phenolic resin organic particles with small particle size and narrow particle size distribution, and also facilitating the close packing of the phenolic resin organic particles, which in turn can make the separator film have better heat resistance and air permeability, and make the secondary battery monomer have better cycle performance.

[0177] In some embodiments, the mass of the second dispersant can be 0.01%-2% of the mass of the broken phenolic resin organic particles, for example, it can be 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or a range consisting of any of the above values.

[0178] The content of the second dispersant can be within the above range, which can optimize the solid content and viscosity of the sanding slurry, thereby facilitating the preparation of phenolic resin organic particles with small particle size and narrow particle size distribution, and also facilitating the close packing of the phenolic resin organic particles, which in turn can make the separator film have better heat resistance and air permeability, and make the secondary battery monomer have better cycle performance.

[0179] Optionally, the second dispersant can be present in an amount of 0.2-2%, 0.4-2%, 0.6-2%, 0.8-2%, 1-2%, 0.2-1.6%, 0.4-1.6%, 0.6-1.6%, 0.8-1.6%, 1-1.6% by mass of the broken phenolic resin-based organic particles.

[0180] In some embodiments, the preparation method further comprises a sieving process and a magnetic removal process after the sanding process.

[0181] The heating and curing process of the resol-based material is the same as the first preparation method described above, and will not be repeated here.

[0182] The present disclosure also provides an isolation membrane. The isolation membrane comprises a porous base membrane and a coating layer on at least one side of the porous base membrane, the coating layer comprising a binder and the phenolic resin-based organic particles of the present disclosure or the phenolic resin-based organic particles prepared by the method of the present disclosure.

[0183] Both the porous base membrane and the coating layer have a pore structure, so that the isolation membrane has good air permeability and facilitates ion passage. The phenolic resin-based organic particles in the coating layer are connected to each other and fixed by the binder, and the gaps between the phenolic resin-based organic particles can form a pore structure.

[0184] In some embodiments, the mass content of the phenolic resin-based organic particles in the coating layer can be 50-99% based on the total mass of the coating layer.

[0185] Optionally, the mass content of the phenolic resin-based organic particles in the coating layer can be 60-99%, 70-99%, 80-99%, 85-99%, 88-99%, 80-97%, 85-97%, 88-97%, 80-95%, 85-95%, 88-95%.

[0186] In some embodiments, the binder in the coating layer can include, but is not limited to, one or more of polyacrylate binder, nitrile rubber binder, polyacrylic acid, polymethacrylic acid, sodium polyacrylate, polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0187] In some embodiments, the coating layer can further comprise a dispersant, such as, but not limited to, a polyacrylate dispersant or a carboxymethyl cellulose dispersant. As an example, the dispersant can include, but is not limited to, one or more of sodium carboxymethyl cellulose, sodium polyacrylate, and ammonium polyacrylate.

[0188] In some embodiments, the isolation membrane can further comprise polymeric binder particles.

[0189] In some embodiments, the polymeric binder particles can be embedded in the phenol resin-based organic particles and form protrusions on the surface of the coating layer.

[0190] In other embodiments, the coating layer of the separation film includes a heat-resistant layer disposed on the porous base film and a bonding layer disposed on at least a portion of the surface of the heat-resistant layer away from the porous base film, the phenol resin-based organic particles are disposed in the heat-resistant layer, and the polymeric binder particles are disposed in the bonding layer.

[0191] In yet other embodiments, the coating layer of the separation film includes a heat-resistant layer disposed on one side of the porous base film and a bonding layer disposed on at least a portion of the surface of the other side of the porous base film, the phenol resin-based organic particles are disposed in the heat-resistant layer, and the polymeric binder particles are disposed in the bonding layer.

[0192] In some embodiments, the average particle diameter of the polymeric binder particles can be 6 μm to 18 μm.

[0193] In some embodiments, the polymeric binder particles can include vinylidene fluoride-based polymeric particles, such as polyvinylidene fluoride (PVDF) particles and / or copolymer particles of a vinylidene fluoride monomer and a comonomer.

[0194] The comonomer can include at least one of an olefin monomer, a fluorine-containing olefin monomer, a chlorine-containing olefin monomer, an acrylate monomer, an acrylic monomer, and a fluorine ether monomer.

[0195] Optionally, the comonomer can include at least one of trifluoroethylene, trifluorochloroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene, perfluoro(alkyl vinyl) ether (e.g., perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether), perfluoro(1,3-dioxolane), and perfluoro(2,2-dimethyl-1,3-dioxolane).

[0196] In some embodiments, the thickness of the coating layer can be 0.5 μm to 5 μm. The thickness of the coating layer refers to the thickness of the coating layer on one side of the porous base film. Optionally, the thickness of the coating layer can be 0.5 μm to 4 μm, 0.5 μm to 3 μm, 0.5 μm to 2 μm, 0.8 μm to 4 μm, 0.8 μm to 3 μm, or 0.8 μm to 2 μm.

[0197] In some embodiments, the areal density of the coating layer can be 0.45 g / m 2 -4.5 g / m 2 .

[0198] In some embodiments, the porous base film can comprise a film or nonwoven web selected from any one or at least two of the following: polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyether sulfone, polyphenylene ether, cyclic olefin copolymer, polyphenylene sulfide, polyvinyl naphthalene.

[0199] The porous base film can be a single layer film or a multi-layer composite film. When the porous base film is a multi-layer composite film, the materials of the layers can be the same or different.

[0200] In some embodiments, the thickness of the porous base film can be 4-12 μm, optionally 4-9 μm.

[0201] In some embodiments, the porosity of the porous base film can be 25-60%, optionally 28-50%.

[0202] In some embodiments, the ratio of the volume distribution particle size Dv50 of the phenolic resin-based organic particles to the average pore size of the porous base film can be greater than or equal to 1.5, optionally, the ratio of the volume distribution particle size Dv50 of the phenolic resin-based organic particles to the average pore size of the porous base film can be greater than or equal to 2, greater than or equal to 2.5.

[0203] The volume distribution particle size Dv50 of the phenolic resin-based organic particles and the average pore size of the porous base film have the same unit, for example, nm.

[0204] This can reduce the problem of pore blocking and improve the air permeability and ion conductivity of the separation film.

[0205] In some embodiments, the average pore size of the porous base film can be 25-82 nm.

[0206] The average pore size of the porous base film can be tested by a capillary porosimetry tester (bubble point method). An exemplary testing method is as follows: a circular sample with a diameter of 25 mm is taken and 3-5 drops of wetting liquid are dropped on it, then the sample is placed in a mold after complete wetting, and then an inert gas (such as nitrogen) is used to press the wetting liquid in the pores of the sample to be tested, the pressure and flow rate of the press are inversely proportional to the pore size, and the average pore size of the sample to be tested is obtained by software sampling and pressure and pore size conversion analysis. The testing instrument can be a CFP 1500 pore size analyzer from PMI, and the testing pressure can be 100-350 psi.

[0207] In some embodiments, the thickness of the separation film can be 5-14 μm, optionally 5-12 μm, 6-12 μm. This is beneficial to improve the energy density of the secondary battery cell.

[0208] In some embodiments, the release film has a longitudinal (MD) heat shrinkage of less than or equal to 2% when heated at 130°C for 1 hour.

[0209] In some embodiments, the release film has a transverse (TD) heat shrinkage of less than or equal to 2% when heated at 130°C for 1 hour.

[0210] In some embodiments, the release film has an air permeability value of 160 s / 100 mL to 230 s / 100 mL, optionally 160 s / 100 mL to 220 s / 100 mL, 160 s / 100 mL to 215 s / 100 mL, 160 s / 100 mL to 210 s / 100 mL, 160 s / 100 mL to 205 s / 100 mL, 160 s / 100 mL to 200 s / 100 mL, 170 s / 100 mL to 220 s / 100 mL, 170 s / 100 mL to 215 s / 100 mL, 170 s / 100 mL to 210 s / 100 mL, 170 s / 100 mL to 205 s / 100 mL, 170 s / 100 mL to 200 s / 100 mL, 180 s / 100 mL to 220 s / 100 mL, 180 s / 100 mL to 215 s / 100 mL, 180 s / 100 mL to 210 s / 100 mL, 180 s / 100 mL to 205 s / 100 mL, 180 s / 100 mL to 200 s / 100 mL.

[0211] It should be noted that the coating parameters of the release film described above are the coating parameters of one side of the porous base film. When the coating is provided on both sides of the porous base film, the coating parameters of any one side thereof satisfying the present disclosure are considered to fall within the protection scope of the present disclosure.

[0212] The release film can be prepared according to methods known in the art.

[0213] In some embodiments, a slurry including the phenolic resin-based organic particles and the binder can be coated on at least one side of the porous base film, and the release film can be obtained after drying.

[0214] In some embodiments, the slurry can further include the polymer binder particles, and the polymer binder particles can be embedded in the phenolic resin-based organic particles and form protrusions on the surface of the coating after drying of the slurry.

[0215] In some embodiments, the method for preparing the release film can include the steps of: coating a heat-resistant layer slurry including the phenolic resin-based organic particles and the binder on at least one side of the porous base film, and drying to form a heat-resistant layer; and coating an adhesive layer slurry including the polymer binder particles and the binder on at least a part of the surface of the heat-resistant layer, and drying to obtain the release film.

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

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

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

[0219] The embodiments of the present disclosure also provide a secondary battery cell. The secondary battery cell includes the separation film provided by the embodiments of the present disclosure. Thus, the secondary battery cell can have high quality energy density, high reliability, and good cycle performance.

[0220] The secondary battery cell also includes a positive electrode sheet, a negative electrode sheet, and an electrolyte, and the separation film is arranged between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the separation film, and the negative electrode sheet can form an electrode assembly through a rolling process and / or a stacking process.

[0221] The secondary battery cell provided by the present disclosure can include, but is not limited to, a lithium battery cell, a sodium battery cell, etc., and the composition of the positive electrode sheet, the negative electrode sheet, and the electrolyte will be different for different types of secondary battery cells.

[0222] [Positive electrode sheet]

[0223] In some embodiments, the positive electrode sheet can include a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector and including a positive electrode active material. For example, the positive electrode current collector has two opposite surfaces in the thickness direction of itself, and the positive electrode film layer is arranged on any one or both of the two opposite surfaces of the positive electrode current collector.

[0224] Taking a lithium battery cell as an example, the positive electrode active material can include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates, and their respective modified compounds. Examples of lithium transition metal oxides can include, but are not limited to, one or more of lithium cobalt oxides, lithium nickel oxides, lithium manganese oxides, lithium nickel cobalt oxides, lithium manganese cobalt oxides, lithium nickel manganese oxides, lithium nickel cobalt manganese oxides, lithium nickel cobalt aluminum oxides, and their respective modified compounds. Examples of lithium-containing phosphates can include, but are not limited to, one or more of lithium iron phosphate, a composite of lithium iron phosphate and carbon, lithium manganese phosphate, a composite of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite of lithium manganese iron phosphate and carbon, and their respective modified compounds. In some embodiments, in order to further improve the energy density of the secondary battery cell, the positive electrode active material can include a compound represented by the general formula Li a Nib Co c M d O e A f One or more of lithium transition metal oxides and their modified compounds. 0.8≤a≤1.2, 0.5≤b<1, 0<c<1, 0<d<1, 1≤e≤2, 0≤f≤1, M includes but is not limited to one or more of Mn, Al, Zr, Zn, Cu, Cr, Mg, Fe, V, Ti and B, and A includes but is not limited to one or more of N, F, S and Cl.

[0225] As an example, the positive electrode active material may include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.1 Al 0.05 One or more of O2, LiFePO4, and LiMnPO4.

[0226] During the charging and discharging process, Li undergoes insertion / extraction and consumption in a single secondary battery cell, resulting in varying molar Li content at different discharge states. In the examples of positive electrode active materials in this disclosure, the molar Li content represents the initial state of the material, i.e., the state before feeding. When the positive electrode active material is applied to a secondary battery cell, the molar Li content changes after charge-discharge cycles. Similarly, in the examples of positive electrode active materials in this disclosure, the molar O content is only a theoretical value. Lattice oxygen release causes changes in the molar O content, and the actual molar O content will also fluctuate.

[0227] Taking sodium-ion battery cells as an example, the positive electrode active material can be one or more of the following, including but not limited to sodium-containing transition metal oxides, polyanionic materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), and Prussian blue materials. For example, the positive electrode active material can be, but is not limited to, NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, and NaNi 1 / 2Ti 1 / 2 O2, NaNi1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, Na Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, Prussian blue type materials, X p M’ q (PO4) r O x Y 3-x materials. In general formula X p M’ q (PO4) r O x Y 3-x , 0 < p < 4, 0 < q < 2, 1 < r < 3, 0 < x < 2, X includes but is not limited to one or more of H + , Li + , Na + , K + and NH4 + , M’ is a transition metal cation, which optionally includes but is not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu and Zn, and Y is a halide anion, which optionally is one or more of F, Cl and Br.

[0228] The modified compound of the positive electrode active material of each of the above lithium battery cell and sodium battery cell can be a doping modification and / or a surface coating modification to the positive electrode active material.

[0229] In some embodiments, the positive electrode film layer can further include a positive electrode conductive agent. As an example, the positive electrode conductive agent can include but is not limited to one or more of super P, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.

[0230] In some embodiments, the positive electrode film layer can further include a positive electrode binder. As an example, the positive electrode binder can include but is not limited to one or more of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylic ester-based resin.

[0231] In some embodiments, the positive current collector may be a metal foil or a composite current collector. An example of a metal foil is aluminum foil. The composite current collector may include a polymeric material substrate and a metal material layer formed on at least one surface of the polymeric material substrate. As an example, the metal material may include, but is not limited to, one or more of aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver, and silver alloys. As an example, the polymeric material substrate may include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0232] The positive electrode film is typically formed by coating a positive electrode slurry onto a positive electrode current collector, followed by drying and cold pressing. The positive electrode slurry is usually formed by dispersing positive electrode active materials, positive electrode conductive agents, positive electrode binders, and any other components in a solvent and stirring until homogeneous. The solvent can be N-methylpyrrolidone (NMP), but is not limited to this.

[0233] [Negative electrode plate]

[0234] In some embodiments, the negative electrode sheet may include a negative current collector and a negative electrode film layer disposed on at least one surface of the negative current collector and comprising a negative electrode active material. For example, the negative current collector has two surfaces opposite each other in its thickness direction, and the negative electrode film layer is disposed on either or both of the two opposite surfaces of the negative current collector.

[0235] The negative electrode active material may be any material known in the art for use in secondary battery cells. As an example, the negative electrode active material may include, but is not limited to, one or more of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may include, but are not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may include, but are not limited to, one or more of elemental tin, tin oxide, and tin alloys.

[0236] In some embodiments, the negative electrode film layer may further include a negative electrode conductive agent. As an example, the negative electrode conductive agent may include, but is not limited to, one or more of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0237] In some embodiments, the negative electrode film layer may further include a negative electrode binder. As an example, the negative electrode binder may include, but is not limited to, one or more of styrene-butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, waterborne acrylic resins (e.g., polyacrylic acid PAA, polymethacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0238] In some embodiments, the negative electrode film layer can further include other auxiliary agents. As an example, the other auxiliary agents can include thickening agents, such as sodium carboxymethyl cellulose (CMC), PTC thermistor materials, and the like.

[0239] In some embodiments, the negative electrode current collector can employ a metal foil or a composite current collector. As an example of the metal foil, a copper foil can be employed. The composite current collector can include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material can include, but is not limited to, one or more of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer can include, but is not limited to, one or more of polypropylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene, and polyethylene.

[0240] The negative electrode film layer is typically formed by coating a negative electrode slurry on a negative electrode current collector, drying, and cold-pressing. The negative electrode slurry is typically formed by dispersing a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and other optional auxiliary agents in a solvent and stirring uniformly. The solvent can be N-methyl pyrrolidone (NMP) or deionized water, but is not limited thereto.

[0241] The negative electrode tab does not exclude other additional functional layers other than the negative electrode film layer. For example, in some embodiments, the negative electrode tab further includes a conductive primer layer (e.g., composed of a conductive agent and a binder) interposed between the negative electrode current collector and the negative electrode film layer and disposed on the surface of the negative electrode current collector.

[0242] In some embodiments, the negative electrode tab can employ a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloy, foamed carbon, or the like. When the foamed metal is employed as the negative electrode tab, the surface of the foamed metal can not be provided with a negative electrode active material, and of course, can be provided with a negative electrode active material.

[0243] [Electrolyte]

[0244] The electrolyte functions to conduct ions between the positive electrode tab and the negative electrode tab.

[0245] In some embodiments, the electrolyte employs an electrolytic solution including an electrolyte salt and an organic solvent.

[0246] For example, in the case of lithium battery cells, the electrolyte salt can include, but is not limited to, one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bisfluorosulfonylimide (LiFSI), lithium bis-trifluoromethanesulfonylimide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluorooxalato borate (LiDFOB), lithium bisoxalato borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalato phosphate (LiDFOP), and lithium tetrafluorooxalato phosphate (LiTFOP).

[0247] For example, in the case of sodium battery cells, the electrolyte salt can include, but is not limited to, one or more of sodium hexafluorophosphate (NaPF6), sodium tetrafluoroborate (NaBF4), sodium perchlorate (NaClO4), sodium hexafluoroarsenate (NaAsF6), sodium bisfluorosulfonylimide (NaFSI), sodium bis-trifluoromethanesulfonylimide (NaTFSI), sodium trifluoromethanesulfonate (NaTFS), sodium difluorooxalato borate (NaDFOB), sodium bisoxalato borate (NaBOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalato phosphate (NaDFOP), and sodium tetrafluorooxalato phosphate (NaTFOP).

[0248] In some embodiments, the organic solvent can include, but is not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), diethyl sulfone (ESE), ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, crown ether.

[0249] In some embodiments, an additive can also be included in the electrolyte. For example, the additive can include a negative electrode film-forming additive, can also include a positive electrode film-forming additive, and can also include an additive capable of improving certain properties of the secondary battery cell, such as an additive capable of improving overcharge performance, an additive capable of improving high-temperature performance, an additive capable of improving low-temperature performance, and the like.

[0250] Optionally, the additive can include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propane sultone (PS), and vinyl sulfate (DTD).

[0251] Methods for preparing secondary battery cells are well known. In some embodiments, a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte can be assembled to form a secondary battery cell. As an example, a positive electrode sheet, a separator, and a negative electrode sheet can be formed into an electrode assembly through a winding process and / or a stacking process, the electrode assembly can be placed in an outer package, an electrolyte described above can be injected after drying, and the secondary battery cell can be obtained through processes such as vacuum packaging, standing, and formation.

[0252] Examples

[0253] The present disclosure is more particularly described in the following examples that are intended to be illustrative only, as numerous modifications and variations within the scope of the present disclosure will become apparent to those skilled in the art. Unless otherwise noted, all parts, percentages, and ratios reported herein are based upon the mass, and all reagents used in the examples are commercially available or synthesized according to standard procedures and used without further purification, and the instruments used in the examples are commercially available.

[0254] A phenolic resin-based material with raw materials of phenol and formaldehyde and a foaming agent of sodium bicarbonate, which are commercially available, were weighed according to a mass ratio of 100:15, mixed and stirred uniformly, and poured into a polytetrafluoroethylene tray; the mixture was placed in a curing oven, the atmosphere was set to air, the temperature was set to 220°C, and the temperature was maintained for curing for 4 h; the cured phenolic resin-based material was taken out, naturally cooled in air, broken by an air jet pulverizer, sand ground by mixing with water, sieved, and de-magnetized to obtain a phenolic resin-based organic particle 1#.

[0255] A phenolic resin-based material with raw materials of phenol and formaldehyde and a foaming agent of sodium bicarbonate, which are commercially available, were weighed according to a mass ratio of 100:20, mixed and stirred uniformly, and poured into a polytetrafluoroethylene tray; the mixture was placed in a curing oven, the atmosphere was set to air, the temperature was set to 220°C, and the temperature was maintained for curing for 4 h; the cured phenolic resin-based material was taken out, naturally cooled in air, broken by an air jet pulverizer, sand ground by mixing with water, sieved, and de-magnetized to obtain a phenolic resin-based organic particle 2#.

[0256] A phenolic aldehyde resin material with raw materials of phenol and formaldehyde and a foaming agent of sodium bicarbonate were weighed according to a mass ratio of 100:10, mixed and stirred uniformly, and then poured into a polytetrafluoroethylene tray; the mixture was placed in a curing oven, the atmosphere was set to air, the temperature was set to 220 DEG C, and the temperature was kept for 4h; the cured phenolic aldehyde resin material was taken out, naturally cooled in air, broken by an air flow crusher, sand ground by mixing with water, sieved, and de-magnetized to obtain a phenolic aldehyde resin organic particle 3#.

[0257] A phenolic aldehyde resin material with raw materials of phenol and formaldehyde and a foaming agent of sodium bicarbonate were weighed according to a mass ratio of 100:5, mixed and stirred uniformly, and then poured into a polytetrafluoroethylene tray; the mixture was placed in a curing oven, the atmosphere was set to air, the temperature was set to 220 DEG C, and the temperature was kept for 4h; the cured phenolic aldehyde resin material was taken out, naturally cooled in air, broken by an air flow crusher, sand ground by mixing with water, sieved, and de-magnetized to obtain a phenolic aldehyde resin organic particle 4#.

[0258] A phenolic aldehyde resin material with raw materials of phenol and formaldehyde and a foaming agent of sodium bicarbonate were weighed according to a mass ratio of 100:1, mixed and stirred uniformly, and then poured into a polytetrafluoroethylene tray; the mixture was placed in a curing oven, the atmosphere was set to air, the temperature was set to 220 DEG C, and the temperature was kept for 4h; the cured phenolic aldehyde resin material was taken out, naturally cooled in air, broken by an air flow crusher, sand ground by mixing with water, sieved, and de-magnetized to obtain a phenolic aldehyde resin organic particle 5#.

[0259] A phenolic aldehyde resin material with raw materials of phenol and formaldehyde and a foaming agent of sodium bicarbonate were weighed according to a mass ratio of 100:15, mixed and stirred uniformly, and then poured into a polytetrafluoroethylene tray; the mixture was placed in a curing oven, the atmosphere was set to air, the temperature was set to 220 DEG C, and the temperature was kept for 4h; the cured phenolic aldehyde resin material was taken out, naturally cooled in air, broken by an air flow crusher, sand ground by mixing with water, sieved, and de-magnetized to obtain a phenolic aldehyde resin organic particle 6#.

[0260] A phenolic aldehyde resin material with raw materials of phenol and formaldehyde was placed in a curing oven, the atmosphere was set to air, the temperature was set to 120 DEG C, and the temperature was kept for 4h; the cured phenolic aldehyde resin material was taken out, naturally cooled in air, broken by an air flow crusher, sand ground by mixing with water, sieved, and de-magnetized to obtain a phenolic aldehyde resin organic particle D1#.

[0261] A commercially available phenol and formaldehyde based resol resin material was placed in a curing oven, the atmosphere was set to air, the temperature was set to 120°C, and the temperature was maintained for 4h of curing; the cured phenol formaldehyde resin material was removed, allowed to cool naturally in air, and then broken up using an air jet mill; the broken up material was then mixed with water and sand milled, sieved, and de-magnetized to obtain phenol formaldehyde resin organic particles D2#.

[0262] Phenol formaldehyde resin organic particles 1# to 6# and D1# were sand milled under the same conditions: the sand mill was operated at 1100rpm for 4h at a temperature of 25°C using zirconium oxide balls as the sand milling media, with a diameter of 0.8mm-1mm.

[0263] Phenol formaldehyde resin organic particles D2# were sand milled for a shorter time than phenol formaldehyde resin organic particles D1#: the sand mill was operated at 1100rpm for 2.5h at a temperature of 25°C using zirconium oxide balls as the sand milling media, with a diameter of 0.8mm-1mm.

[0264] A commercially available phenol and formaldehyde based resol resin material was placed in a curing oven, the atmosphere was set to air, the temperature was set to 220°C, and the temperature was maintained for 4h of curing; the cured phenol formaldehyde resin material was removed, allowed to cool naturally in air, and then broken up using an air jet mill; the broken up material was then mixed with 10g polyoxyethylene ether and 1kg deionized water and sand milled in a 5L sand mill, the sand mill was operated at 1500rpm for 2h at a temperature of 25°C using zirconium oxide balls as the sand milling media, with a diameter of 0.8mm-1mm; deionized water was added to adjust the viscosity; the sand milling was continued for a further 3h to obtain a slurry with a viscosity of 2620mPa.s and a solid content of 23%, the slurry was filtered, sieved, and de-magnetized to obtain phenol formaldehyde resin organic particles 7#.

[0265] Phenolic resin-based organic particle performance test

[0266] (1) Melting point test of phenol formaldehyde resin organic particles

[0267] An appropriate amount of sample (e.g. 5mg-15mg) was placed in a differential scanning calorimeter (DSC) crucible, levelled, and covered with a crucible lid; the parameters were set as follows: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; temperature ramp: temperature ramp rate 10°C / min, temperature range 35°C-300°C. The presence or absence of a melting point for the phenol formaldehyde resin organic particles was determined from the DSC curve.

[0268] (2) Particle size test

[0269] Dv10, Dv50, Dv90 respectively represent the particle size corresponding to the cumulative volume distribution percentage of 10%, 50%, 90% of the material. The test standard refers to GB / T 19077-2016. The test instrument is MasterSizer 3000 laser particle size analyzer. During testing, a clean small beaker is taken to add 1 g of the sample to be tested, 20 ml of deionized water is added, and ultrasonic is performed at 53 KHz / 120 W for 5 min to ensure that the sample is completely dispersed; turn on the laser particle size analyzer, clean the light path system, and then automatically test the background; stir the ultrasonically treated sample solution to make it uniformly dispersed, place it in the sample cell as required, and start measuring the particle size.

[0270] The phenolic resin-based organic particles 1# to 7# prepared above meet the following characteristics: the phenolic resin-based organic particles are thermosetting resol resin, which has no melting point.

[0271] Next, the phenolic resin-based organic particles prepared above are used in the separator film to verify their influence on the performance of the separator film and the secondary battery cell.

[0272] The secondary battery cell preparation process is as follows.

[0273] Preparation of the separator film: a commercially available polyethylene microporous film with a thickness of 7 μm is used as the porous base film; the phenolic resin-based organic particles prepared above, the dispersant sodium carboxymethyl cellulose, and the binder polyacrylate are mixed uniformly in deionized water at a solid mass ratio of 90:2:8 to obtain a slurry; the slurry is uniformly coated on both surfaces of the porous base film at a loading of 2.2 g / m 2 , and dried to remove the solvent to obtain the separator film.

[0274] Preparation of the positive electrode sheet: the positive electrode active material LiFePO4, the positive electrode binder polyvinylidene fluoride (PVDF), and the positive electrode conductive agent carbon black are added to N-methyl pyrrolidone (NMP) at a mass ratio of 97:2:1, and are fully stirred and mixed uniformly to prepare a positive electrode slurry; the positive electrode slurry is uniformly coated on the positive electrode current collector aluminum foil, and then is subjected to drying, cold pressing, and slitting to obtain the positive electrode sheet.

[0275] Preparation of the negative electrode sheet: the negative electrode active material artificial graphite, the negative electrode conductive agent acetylene black, the negative electrode binder styrene-butadiene rubber (SBR), and the thickening agent sodium carboxymethyl cellulose are added to deionized water at a mass ratio of 96.0:1.4:1.5:1.1, and are fully stirred and mixed uniformly to prepare a negative electrode slurry; the negative electrode slurry is uniformly coated on the negative electrode current collector copper foil, and then is subjected to drying, cold pressing, and slitting to obtain the negative electrode sheet.

[0276] Preparation of electrolyte: at 25℃, mix ethylene carbonate (EC) and methyl ethyl carbonate (EMC) in a volume ratio of 3:7 to obtain a mixed solvent, then dissolve LiPF6 and vinylene carbonate (VC) in the above mixed solvent to obtain an electrolyte. The concentration of LiPF6 is 1 mol / L. The mass fraction of VC is 3% based on the mass of the electrolyte.

[0277] Preparation of secondary battery monomer: stack the positive electrode sheet, the separator film and the negative electrode sheet in sequence and wind and hot press to form an electrode assembly; place the electrode assembly in a hard shell outer package, add the electrolyte prepared above, and after processes such as packaging, standing, formation and aging, a secondary battery monomer is obtained.

[0278] Performance test

[0279] (1) Heat shrinkage rate test of the separator film

[0280] The heat shrinkage rate test of the separator film can refer to GB / T 36363-2018.

[0281] Cut the separator film into a sample with a width of 50 mm and a length of 100 mm using a punch machine, place 5 parallel samples on an A4 paper, and then place the A4 paper containing the samples on a corrugated paper with a thickness of 1 mm to 5 mm.

[0282] Set the temperature of the air blowing oven to 130℃, and after the temperature reaches the set temperature and stabilizes for 60 min, place the A4 paper placed on the corrugated paper into the air blowing oven, start timing, and after reaching the set time (1 h in the present disclosure), measure the length and width of the separator film, and the values are marked as a and b respectively.

[0283] Heat shrinkage rate calculation: longitudinal (MD) heat shrinkage rate = [(100-a) / 100] x 100%, transverse (TD) heat shrinkage rate = [(50-b) / 50] x 100%, and the average value of 3 parallel samples is taken as the test result.

[0284] (2) Air permeability test of the separator film

[0285] The air permeability test of the separator film can refer to GB / T 36363-2018.

[0286] Cut the separator film into a square of 5 cm in size, use an air permeability instrument, apply a pressure of 1.21 kPa, and test the time required for 100 ml of air to pass through 6.45 cm 2 of the separator film, and take the average value of 3 parallel samples as the test result. The larger the air permeability value of the separator film, the worse the air permeability.

[0287] (3) Cycle performance test of the secondary battery monomer

[0288] The secondary battery cell was charged at 25℃ at 1 / 3C constant current to 3.8V, then charged at 3.8V constant voltage to a current of 0.05C, rested for 5min, then discharged at 1 / 3C constant current to 2.0V, and the obtained discharge capacity was recorded as initial capacity C0; the above charging and discharging steps were repeated, and the discharge capacity of the secondary battery cell after the nth cycle was recorded as Cn, then the capacity retention rate Pn of the secondary battery cell after each cycle was (Cn / C0)×100%.

[0289] Table 1

[0290]

[0291] It can be seen from the above test results that the phenolic resin organic particles satisfying the volume distribution particle size Dv50 of 100nm-800nm and the particle size distribution (Dv90-Dv10) / Dv50 of 1.4-3 at the same time can make the separator film have higher air permeability and lower heat shrinkage at the same time, and also can make the secondary battery cell have better cycle performance.

[0292] It should be noted that the present disclosure is not limited to the above embodiments. The above embodiments are only examples, and embodiments having substantially the same technical idea and playing the same role and effect within the technical solution range of the present disclosure are all included in the technical solution range of the present disclosure. In addition, within the scope of the main idea of the present disclosure, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present disclosure.

Claims

1. A phenol-aldehyde resin-based organic particle, characterized by, The volume distribution particle size Dv50 of the phenolic resin organic particles is 100-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin organic particles is 1.4-3.

2. The phenol resin-based organic particle according to claim 1, characterized by, The volume distribution particle size Dv50 of the phenolic resin organic particles is 200-600 nm.

3. The phenol-formaldehyde resin-based organic particles according to any one of claims 1 to 2, characterized in that, The particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin organic particles is 1.6-2.

7.

4. The phenolic resin organic particles according to any one of claims 1-3, wherein, The volume distribution particle size Dv90 of the phenolic resin organic particles is 800-1800 nm; and / or, The volume distribution particle size Dv10 of the phenolic resin organic particles is 50-200 nm.

5. The phenolic resin organic particles according to any one of claims 1-4, wherein, The volume distribution particle size Dv90 of the phenolic resin organic particles is 820-1250 nm; and / or, The volume distribution particle size Dv10 of the phenolic resin organic particles is 90-185 nm.

6. The phenol-formaldehyde resin-based organic particles according to any one of claims 1 to 5, characterized in that, The phenolic resin organic particles have no melting point; and / or, the phenolic resin organic particles have no glass transition temperature below 300°C.

7. The phenol-formaldehyde resin-based organic particles according to any one of claims 1 to 6, characterized in that, The phenolic resin organic particles are thermosetting resol.

8. The phenol-formaldehyde resin-based organic particles according to any one of claims 1 to 7, characterized in that, The phenolic resin-based organic particles have a true density of 1.0 g / cm 3 -1.4 g / cm 3 .

9. A method for preparing phenolic resin organic particles, comprising the following steps: providing a resol phenolic resin material; heating and curing the resol phenolic resin material to obtain a to-be-crushed phenolic resin material; crushing the to-be-crushed phenolic resin material to obtain crushed phenolic resin organic particles; mixing the crushed phenolic resin organic particles with a first dispersant and water to obtain a sanding slurry, and then performing sanding treatment and filtration treatment to obtain phenolic resin organic particles, the first dispersant being a high molecular dispersant, the volume distribution particle size Dv50 of the phenolic resin organic particles being 100-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin organic particles being 1.4-3.

10. The method according to claim 9, wherein, The first dispersant comprises one or more of a polyether dispersant, a polyacrylic acid dispersant, a polycarboxylate dispersant, polyvinylpyrrolidone, and polyethylene glycol; and / or, The mass of the first dispersant is 0.01%-2% of the mass of the crushed phenolic resin organic particles.

11. A method for preparing phenolic resin organic particles, comprising the following steps: providing a foaming agent and a resol phenolic resin material; mixing the foaming agent and the resol phenolic resin material uniformly, and then performing heating and curing to obtain a to-be-crushed phenolic resin material; crushing the to-be-crushed phenolic resin material to obtain crushed phenolic resin organic particles; The broken phenolic resin organic particles are subjected to sand milling to obtain phenolic resin organic particles, the volume distribution particle size Dv50 of the phenolic resin organic particles is 100 nm-800 nm, and the particle size distribution (Dv90-Dv10) / Dv50 of the phenolic resin organic particles is 1.4-3.

12. The method of claim 11, wherein, the mass of the foaming agent is 1%-20% of the mass of the resol phenolic resin material; and / or, the foaming agent comprises an organic foaming agent and / or an inorganic foaming agent.

13. The method according to any of claims 11-12, characterized by, The second dispersant is further added when the broken phenolic resin organic particles are subjected to sand milling.

14. The method of claim 13, wherein, the second dispersant comprises one or more of a polyether dispersant, a polyacrylic acid dispersant, a polycarboxylate dispersant, polyvinylpyrrolidone, and polyethylene glycol; and / or, the mass of the second dispersant is 0.01%-2% of the mass of the broken phenolic resin organic particles.

15. A separator membrane comprising a porous base membrane and a coating on at least one side of the porous base membrane, characterized in that, The coating comprises the phenolic resin organic particles of any one of claims 1-8, or the phenolic resin organic particles prepared by the method of any one of claims 9-14.

16. The separator film of claim 15, wherein, the mass content of the phenolic resin organic particles in the coating is 50%-99% based on the total mass of the coating; and / or, the thickness of the coating is 0.5 μm-5 μm; and / or, The areal density of the coating is 0.45 g / m 2 - 4.5 g / m 2 .

17. The separator membrane according to any one of claims 15-16, characterized in that, the ratio of the volume distribution particle size Dv50 of the phenolic resin organic particles to the average pore size of the porous base film is greater than or equal to 1.

5.

18. The separator film of any one of claims 15-17, wherein, the longitudinal heat shrinkage of the separator film is less than or equal to 2% when heated at 130°C for 1 h; and / or, the transverse heat shrinkage of the separator film is less than or equal to 2% when heated at 130°C for 1 h; and / or, the air permeability of the separator film is 160 s / 100 mL-230 s / 100 mL.

19. A secondary battery cell characterized by comprising: The separator film of any one of claims 15-18 is disposed between the positive electrode sheet and the negative electrode sheet.

20. A battery device, characterized by The secondary battery device comprises a plurality of the secondary battery cells of claim 19.

21. An electrical device, comprising: The secondary battery device comprises the secondary battery cell of claim 19 or the battery device of claim 20.

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