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 an electric device. The initial thermal weight loss temperature T3d of the phenolic resin type organic particles is 290-346 DEG C. 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. 202410947890.0, filed on July 15, 2024, entitled “Phenolic Resin Organic Particles, Preparation Method Thereof, Isolation Film, Battery Cell, and Electrical Device,” the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to a phenolic resin organic particle, a preparation method thereof, an isolation film, a secondary battery cell, a battery device, and an electrical 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 performance under the premise of high reliability is a technical problem to be solved at present. SUMMARY

[0004] The present disclosure provides a phenolic resin organic particle, a preparation method thereof, an isolation film, a secondary battery cell, a battery device, and an electrical device. The phenolic resin organic particle is used in the isolation film, and the secondary battery cell has high mass energy density, high reliability, and good cycle performance.

[0005] In a first aspect, the present disclosure provides a phenolic resin organic particle, wherein the initial thermal weight loss temperature T 3d of the phenolic resin organic particle is 290°C-346°C.

[0006] The density of the phenolic resin organic particle is small, and the secondary battery cell using the same can have higher mass energy density. The initial thermal weight loss temperature T 3d of the phenolic resin organic particle is high, indicating that the weight of the phenolic resin organic particle does not change significantly at high temperatures, thereby having high heat resistance and thermal stability, and not being prone to decomposition or pyrolysis during the use and thermal abuse of the secondary battery cell. By using the phenolic resin organic particle in the isolation film, the phenolic resin organic particle can generate a force to resist the shrinkage of the isolation film, thereby improving the overall thermal shrinkage of the isolation film, improving the heat resistance of the isolation film, and improving the reliability of the secondary battery cell. The initial thermal weight loss temperature T 3d of the phenolic resin organic particle is high, and the volatile content in the particle is also small. The phenolic resin organic particle is not prone to react with other substances during the charging and discharging process of the secondary battery cell, thereby being stably present in the electrolyte, and further enabling the secondary battery cell to have good cycle performance. Therefore, the phenolic resin organic particle of the present disclosure used in the isolation film 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 an initial thermal weight loss temperature T 3d is 310℃-346℃.

[0008] The phenolic resin-based organic particles have an initial thermal weight loss temperature T 3d Within the above range, the thermal shrinkage of the separator film as a whole can be better improved, the reliability of the secondary battery cell is further improved, and the secondary battery cell can also have good cycle stability.

[0009] In some embodiments, the phenolic resin-based organic particles have no melting point.

[0010] 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 the thermal shrinkage of the separator film, improving the heat resistance of the separator film, and improving the reliability of the secondary battery cell.

[0011] In some embodiments, the phenolic resin-based organic particles are thermosetting resol.

[0012] In some embodiments, the phenolic resin-based organic particles have a volume distribution particle size Dv50 of 200nm-850nm.

[0013] In some embodiments, the phenolic resin-based organic particles have a true density of 1.0g / cm 3 -1.4g / cm 3 Thereby, the secondary battery cell using the separator film of the present disclosure can have higher mass energy density.

[0014] 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; curing the resol phenolic resin-based material at a first temperature and in a first atmosphere for a first time, and then curing at a second temperature and in a second atmosphere for a second time, the first temperature being 80℃-160℃, and the second temperature being 180℃-270℃; and then crushing to obtain the phenolic resin-based organic particles.

[0015] In some embodiments, the first atmosphere is an oxygen-containing atmosphere or an inert atmosphere, and the oxygen-containing atmosphere has an oxygen volume fraction of 5%-50%.

[0016] In some embodiments, the second atmosphere is an oxygen-containing atmosphere or an inert atmosphere, and the oxygen-containing atmosphere has an oxygen volume fraction of 5%-50%.

[0017] In some embodiments, the first time is 1h-3h, and / or the second time is 1h-5h.

[0018] In some embodiments, the method for preparing the resol resin-like material comprises the step of: reacting a phenolic compound and an aldehyde compound under catalysis of an alkaline substance to obtain the resol resin-like material.

[0019] In some embodiments, the phenolic compound comprises one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cardanol.

[0020] In some embodiments, the aldehyde compound comprises one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0021] In some embodiments, the mass content of the resol resin-like organic particles in the coating layer is 50%-99% based on the total mass of the coating layer.

[0022] In some embodiments, the thickness of the coating layer is 0.5 μm-5 μm.

[0023] In some embodiments, the areal density of the coating layer is 0.45 g / m 2 -4.5 g / m 2 .

[0024] In some embodiments, the ratio of the volume distribution particle size Dv50 of the resol resin-like organic particles to the average pore size of the porous base film is greater than or equal to 2.5.

[0025] In some embodiments, the heat shrinkage rate of the separator film in the longitudinal direction is less than or equal to 2% when heated at 130°C for 1 h.

[0026] In some embodiments, the heat shrinkage rate of the separator film in the transverse direction is less than or equal to 2% when heated at 130°C for 1 h.

[0027] In some embodiments, the heat shrinkage rate of the separator film in the transverse direction is less than or equal to 2% when heated at 130°C for 1 h.

[0028] In some embodiments, the heat shrinkage rate of the separator film in the transverse direction is less than or equal to 2% when heated at 130°C for 1 h.

[0029] In some embodiments, the heat shrinkage rate of the separator film in the transverse direction is less than or equal to 2% when heated at 130°C for 1 h.

[0030] In some embodiments, the heat shrinkage rate of the separator film in the transverse direction is less than or equal to 2% when heated at 130°C for 1 h. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required to be used in the embodiments of the present disclosure will be briefly introduced below. Obviously, the drawings described below are only some of the embodiments of the present disclosure, and other drawings can also be obtained by the drawings without paying creative labor for those skilled in the art.

[0032] Figure 1 A schematic diagram of a secondary battery cell provided by some embodiments of the present disclosure is shown.

[0033] Figure 2 A schematic diagram of an electrical device provided by some embodiments of the present disclosure is shown.

[0034] In the drawings, the drawings are not necessarily drawn according to the actual scale. DETAILED DESCRIPTION

[0035] Hereinafter, specific embodiments of the phenolic resin-based organic particles and the method for producing the same, the separator, the secondary battery cell, the battery device, and the electrical device of the present disclosure will be specifically described with appropriate reference to the drawings. However, there will be cases where unnecessary detailed description is omitted. For example, there will be cases where detailed description of matters known well, repeated description of substantially the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided in order for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In the present disclosure, the terms "a plurality of", "a plurality of" refer to two or more.

[0042] 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.

[0043] Unless otherwise specified, the test temperature of each parameter mentioned in the present disclosure is 25°C.

[0044] 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.

[0045] 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.

[0046] 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 also 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).

[0047] 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.

[0048] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of secondary battery cells.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] The initial thermal weight loss temperature T 3d of the phenolic resin-based organic particles of the present disclosure is 290-346℃.

[0062] The density of the phenolic resin-based organic particles is small, and the secondary battery cell using the same has higher mass energy density.

[0063] The initial thermal weight loss temperature T 3d of the currently commercially available phenolic resin-based organic particles does not meet the requirements of the separator film. The weight change of the thermal weight loss reaction material under high temperature environment. The initial thermal weight loss temperature T 3d of the phenolic resin-based organic particles is high, indicating that the weight does not change significantly at high temperature, and thus the phenolic resin-based organic particles have high heat resistance and thermal stability and are not easy to decompose or pyrolyze during the use process and thermal abuse process of the secondary battery cell. By using the phenolic resin-based organic particles 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.

[0064] The initial thermal weight loss temperature T 3d of the phenolic resin-based organic particles is high, and the volatile content in the particles is also small. The phenolic resin-based organic particles are not easy to react with other substances during the charge-discharge process of the secondary battery cell, and thus can exist stably in the electrolyte, and further can make the secondary battery cell have good cycle performance.

[0065] 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.

[0066] The initial thermal weight loss temperature T 3dmay be 290℃-346℃, for example, 290℃, 300℃, 305℃, 310℃, 315℃, 320℃, 325℃, 330℃, 335℃, 340℃, 346℃, or a range consisting of any of the above values.

[0067] Optionally, in some embodiments, the phenolic resin-based organic particles have an initial thermal weight loss temperature T 3d may be 300℃-346℃, 310℃-346℃, 315℃-346℃, 320℃-346℃.

[0068] The initial thermal weight loss temperature T 3d refers to the temperature corresponding to a 3% loss in the mass of the sample relative to the initial mass in the thermal gravimetric analysis.

[0069] The initial thermal weight loss temperature T 3d Within the above range, the thermal shrinkage of the entire separator film can be better improved, further improving the reliability of the secondary battery cell, and the secondary battery cell can also have better cycle stability.

[0070] The initial thermal weight loss temperature T 3d may be tested as follows: an appropriate amount of sample (for example, 5mg-15mg) is placed in an alumina crucible of a thermal gravimetric analyzer (TGA), leveled, and covered with a crucible cover; the parameters are set as follows: nitrogen atmosphere, purging gas 60mL / min, protective gas 20mL / min; temperature rising program: temperature rising rate 10℃ / min, temperature range 35℃-600℃; the temperature corresponding to a 3% loss in the mass of the sample relative to the initial mass (i.e., 97% of the initial mass) is obtained from the test curve, which is the initial thermal weight loss temperature T 3d .

[0071] In some embodiments, the phenolic resin-based organic particles have a true density of 1.0g / cm 3 -1.4g / cm 3 .

[0072] At present, the true density of inorganic particles such as boehmite and alumina is usually 2.5g / cm 3 -3.5g / cm 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.

[0073] 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), chloroform, at 25℃, i.e. insoluble in the mobile phase for gel permeation chromatography test, and the molecular weight of the phenolic resin-based organic particles cannot be tested by gel permeation chromatography.

[0074] In some embodiments, the phenolic resin-based organic particles are thermosetting resins.

[0075] In some embodiments, the phenolic resin-based organic particles are thermosetting resol.

[0076] In some embodiments, the phenolic resin-based organic particles have no melting point.

[0077] 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 isolation film, improving the heat resistance of the isolation film, and improving the reliability of the secondary battery cell.

[0078] The melting point can be tested according to the following method: take an appropriate amount of sample (e.g. 5mg-15mg) and place it in a differential scanning calorimeter (DSC) crucible, shake it flat, and cover it with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: temperature rise from 25℃ to 200℃ at a rate of 10℃ / min, hold for 5min to eliminate thermal history, temperature drop from 200℃ to -40℃ at a rate of 10℃ / min, and temperature rise from -40℃ to 300℃ at a rate of 10℃ / min. Whether the phenolic resin-based organic particles have a melting point below 300℃ is determined by the DSC curve. The phenolic resin-based organic particles have no melting point, meaning that the DSC curve of the phenolic resin-based organic particles has no melting peak.

[0079] In some embodiments, the volume distribution particle size Dv50 of the phenolic resin-based organic particles can be 200nm-850nm.

[0080] Dv50 represents the particle size corresponding to the cumulative volume distribution percentage of 50%, which can be tested by laser particle size analyzer according to GB / T19077-2016. During the test, a clean small beaker is taken and 1g of the sample to be tested is added, 20ml of deionized water is added, and ultrasonic treatment is performed at 53KHz / 120W for 5min 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. The test instrument can be a MasterSizer 3000 laser particle size analyzer.

[0081] The present disclosure also provides a preparation method of the phenolic resin organic particles.

[0082] The preparation method of the phenolic resin organic particles comprises the following steps: providing a resol phenolic resin material; curing the resol phenolic resin material at a first temperature and in a first atmosphere for a first time, then curing the resol phenolic resin material at a second temperature and in a second atmosphere for a second time, and then crushing to obtain the phenolic resin organic particles. The first temperature is 80-160°C, and the second temperature is 180-270°C.

[0083] The resol phenolic resin material can form a resol phenolic resin material with a network structure through condensation reaction of phenolic and aldehyde groups. However, the existing resol phenolic resin material curing process is usually curing at room temperature or directly heating to below 150°C for curing. The above curing method cannot fully cure the resol phenolic resin material, thereby resulting in that the heat resistance of the obtained resol phenolic resin material is not excellent, and the initial thermal weight loss temperature T 3d is small. The present disclosure obtains a phenolic resin organic particle with better heat resistance by segmenting the curing of the resol phenolic resin material. The preparation method provided by the present disclosure has simple process and does not need complex operation, and therefore has low production cost.

[0084] The first temperature is 80-160°C, for example, can be 80°C, 90°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, or a range consisting of any of the above values.

[0085] The first temperature in the above range is beneficial to eliminate small molecule groups and easily oxidizable groups, thereby the initial thermal weight loss temperature T 3d of the phenolic resin organic particle can be obtained.

[0086] Optionally, the first temperature can be 95-160°C, 105-160°C, 110-160°C, 120-160°C.

[0087] The first temperature in the above range can further improve the initial thermal weight loss temperature T 3d of the phenolic resin organic particle.

[0088] The second temperature can be in the range of 180-270°C, for example, 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, or any range derivable therein.

[0089] The second temperature in the above range can further improve the initial thermal weight loss temperature T 3d The phenolic resin-based organic particles have an initial thermal weight loss temperature T

[0090] Optionally, the second temperature can be in the range of 200-270°C, 210-270°C, 215-270°C, 200-265°C, 210-265°C, 215-265°C, 200-260°C, 210-260°C, 215-260°C, 200-255°C, 210-255°C, 215-255°C, 200-250°C, 210-250°C, 215-250°C.

[0091] The second temperature in the above range can further improve the initial thermal weight loss temperature T 3d .

[0092] In some embodiments, the first time can be in the range of 1-3h, for example, 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, or any range derivable therein.

[0093] The first time in the above range can further improve the initial thermal weight loss temperature T 3d .

[0094] In some embodiments, the second time can be in the range of 1-5h, for example, 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.

[0095] The second time in the above range can further improve the initial thermal weight loss temperature T 3d .

[0096] In some embodiments, the first atmosphere can be an inert gas atmosphere or an oxygen-containing atmosphere. The oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5%-50%. Optionally, the inert gas can include one or more of nitrogen, argon, helium, but not limited to.

[0097] Optionally, the first atmosphere is an oxygen-containing atmosphere, and the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More optionally, the first atmosphere can be an air atmosphere.

[0098] In some embodiments, the second atmosphere can be an inert gas atmosphere or an oxygen-containing atmosphere. The oxygen-containing atmosphere can include oxygen and an inert gas. Optionally, the volume fraction of oxygen in the oxygen-containing atmosphere can be 5%-50%. Optionally, the inert gas can include one or more of nitrogen, argon, helium, but not limited to.

[0099] Optionally, the second atmosphere is an oxygen-containing atmosphere, and the volume fraction of oxygen in the oxygen-containing atmosphere can be 10%-30%. More optionally, the second atmosphere can be an air atmosphere.

[0100] The first-stage curing and the second-stage curing are selected to be performed under an oxygen-containing atmosphere, which can make the phenolic resin-based organic particles have a higher initial thermal weight loss temperature T 3d and better oxidation resistance. Performing the curing in an oxygen-containing atmosphere can make the easily-oxidizable 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 increasing the initial thermal weight loss temperature T 3d and oxidation resistance of the phenolic resin-based organic particles.

[0101] In some embodiments, the crushing treatment can include a coarse crushing treatment, a re-crushing treatment, and a sand milling treatment.

[0102] In some embodiments, the method for preparing the phenolic resin-based organic particles further includes the steps of a sieving treatment and a magnetic removal treatment after the crushing treatment.

[0103] Optionally, the magnetic removal treatment can be a wet magnetic removal treatment. Optionally, the material after the wet magnetic removal treatment can be directly used to prepare a coating slurry of the release film.

[0104] 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 step of: reacting a phenolic compound and an aldehyde compound under catalysis of an alkaline substance to obtain the resol-based material.

[0105] Optionally, the alkaline substance can include one or more of ammonia, NaOH, Na2CO3.

[0106] Optionally, the phenolic compound can include one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cardanol.

[0107] Optionally, the aldehyde compound can include one or more of formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, glyoxal, and furfural.

[0108] The present disclosure also provides a separator membrane. The separator membrane includes a porous base membrane and a coating layer on at least one side of the porous base membrane, the coating layer including 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.

[0109] Both the porous base membrane and the coating layer have a pore structure, so that the separator 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.

[0110] 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.

[0111] 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%.

[0112] 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).

[0113] In some embodiments, the coating layer can further include a dispersant, such as can include, but is not limited to, a polyacrylic acid 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.

[0114] In some embodiments, the separator membrane can further include polymeric binder particles.

[0115] In some embodiments, the polymeric binder particles can be embedded in the phenolic resin-based organic particles and form protrusions on the surface of the coating layer.

[0116] In other embodiments, the coating of the separation membrane includes a heat-resistant layer disposed on the porous base membrane and a bonding layer disposed on at least a portion of a surface of the heat-resistant layer away from the porous base membrane, the phenol resin-based organic particles are disposed in the heat-resistant layer, and the polymer binder particles are disposed in the bonding layer.

[0117] In yet other embodiments, the coating of the separation membrane includes a heat-resistant layer disposed on one side of the porous base membrane and a bonding layer disposed on at least a portion of a surface of the other side of the porous base membrane, the phenol resin-based organic particles are disposed in the heat-resistant layer, and the polymer binder particles are disposed in the bonding layer.

[0118] In some embodiments, the average particle diameter of the polymer binder particles can be 6 μm to 18 μm.

[0119] In some embodiments, the polymer binder particles can include vinylidene fluoride-based polymer particles, such as polyvinylidene fluoride (PVDF) particles and / or copolymer particles of a vinylidene fluoride monomer and a comonomer.

[0120] 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 fluorinated ether monomer.

[0121] Optionally, the comonomer can include at least one of trifluoroethylene, chlorotrifluoroethylene, 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).

[0122] In some embodiments, the thickness of the coating can be 0.5 μm to 5 μm. The thickness of the coating refers to the thickness of the coating on one side of the porous base membrane. Optionally, the thickness of the coating 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, 0.8 μm to 2 μm.

[0123] In some embodiments, the areal density of the coating can be 0.45 g / m 2 -4.5 g / m 2 .

[0124] 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.

[0125] 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.

[0126] In some embodiments, the thickness of the porous base film can be 4-12 μm, optionally 4-9 μm.

[0127] In some embodiments, the porosity of the porous base film can be 25-60%, optionally 28-50%.

[0128] 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 2.5.

[0129] 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.

[0130] This can reduce the problem of pore blocking and improve the air permeability and ion conductivity of the separation film.

[0131] In some embodiments, the average pore size of the porous base film can be 25-82 nm.

[0132] The average pore size of the porous base film can be tested using a capillary porosimeter (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. After the sample is completely wetted, it is placed in a mold, 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 pressurized gas are inversely proportional to the pore size. 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.

[0133] In some embodiments, the thickness of the separation film can be 5-14 μm, optionally 5-12 μm, 6-12 μm. This is beneficial for improving the energy density of the secondary battery cell.

[0134] In some embodiments, the longitudinal (MD) heat shrinkage rate of the separation film can be less than or equal to 2%, optionally less than or equal to 1.5%, when heated at 130°C for 1 h.

[0135] In some embodiments, the isolation film has a transverse direction (TD) heat shrinkage of less than or equal to 2%, and optionally less than or equal to 1.5%, when heated at 130°C for 1 hour.

[0136] It should be noted that the coating parameters of the isolation film described above are the coating parameters of one side of the porous base film. When the coating is arranged on both sides of the porous base film, as long as the coating parameters of any one side meet the present disclosure, it is considered to fall within the protection scope of the present disclosure.

[0137] The isolation film can be prepared according to methods known in the art.

[0138] 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 after drying, the isolation film is obtained.

[0139] In some embodiments, the slurry can further include polymer binder particles, and after drying of the slurry, the polymer binder particles are embedded in the phenolic resin-based organic particles and form protrusions on the surface of the coating.

[0140] In some embodiments, the method for preparing the isolation film can include: a step 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 after drying, forming a heat-resistant layer; and a step of 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 after drying, obtaining the isolation film.

[0141] In some embodiments, the method for preparing the isolation film can include: a step of coating a heat-resistant slurry including the phenolic resin-based organic particles and the binder on one side of the porous base film, and a step of coating an adhesive layer slurry including the polymer binder particles and the binder on at least a part of the surface of the other side of the porous base film, and after drying, obtaining the isolation film.

[0142] In some embodiments, the solvent of the slurry can be water, for example, deionized water.

[0143] In some embodiments, the slurry can further include other components, for example, can further include a dispersant and / or a wetting agent, etc.

[0144] The present disclosure also provides a secondary battery cell. The secondary battery cell includes the isolation film provided by the present disclosure. Thus, the secondary battery cell can have high mass energy density, high reliability, and good cycle performance.

[0145] The secondary battery cell further includes a positive electrode sheet, a negative electrode sheet, and an electrolyte, and the isolation film is arranged between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the isolation film, and the negative electrode sheet can form an electrode assembly through a rolling process and / or a stacking process.

[0146] 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 type of the secondary battery cell is different, and the composition of the positive electrode tab, the negative electrode tab, and the electrolyte will be different.

[0147] [Positive electrode tab]

[0148] In some embodiments, the positive electrode tab can include a positive electrode current collector and a positive electrode film layer disposed 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 surfaces opposite in the thickness direction of itself, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.

[0149] 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 one or more of lithium transition metal oxides of the general formula Li a Ni b Co c M d O e A f 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.

[0150] As an example, the positive electrode active material can include, but is not limited to, LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 Co 0.2 Mn 0.2O2(NCM622), LiNi 0.8 Co 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 Co 0.1 Al 0.05 O2, LiFePO4, LiMnPO4.

[0151] The secondary battery cell will be accompanied by Li de-intercalation and consumption during charging and discharging process, and the molar content of Li is different when the secondary battery cell is discharged to different states. In the enumeration of the positive electrode active material in this disclosure, the molar content of Li is the initial state of the material, that is, the state before feeding, and the positive electrode active material is applied to the secondary battery cell. After charging and discharging cycle, the molar content of Li will change. In the enumeration of the positive electrode active material in this disclosure, the molar content of O is only the theoretical state value, and the lattice oxygen release will cause the molar content of O to change, and the actual molar content of O will also appear floating.

[0152] Taking a sodium battery cell as an example, the positive electrode active material can include but is not limited to one or more of sodium-containing transition metal oxides, polyanion materials (such as phosphates, fluorophosphates, pyrophosphates, sulfates, etc.), prussian blue type materials. As an example, the positive electrode active material can include but is not limited to NaFeO2, NaCoO2, NaCrO2, NaMnO2, NaNiO2, NaNi 1 / 2Ti 1 / 2 O2, NaNi 1 / 2 Mn 1 / 2 O2, Na 2 / 3 Fe 1 / 3 Mn 2 / 3 O2, NaNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, NaFePO4, NaMnPO4, NaCoPO4, prussian blue type material, material of general formula X p M’ q (PO4) r O x Y 3-x or more. In the general formula X p M’ q (PO4) r O x Y 3-x , 0 + , Li + , Na + , K + and NH4 +M' is a transition metal cation, optionally including but not limited to one or more of V, Ti, Mn, Fe, Co, Ni, Cu, and Zn, Y is a halide anion, optionally one or more of F, Cl, and Br.

[0153] The modified compound of the positive electrode active material of each of the above lithium secondary battery cell and sodium secondary battery cell can be a doping modification and / or a surface coating modification to the positive electrode active material.

[0154] 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.

[0155] 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 resin.

[0156] In some embodiments, the positive electrode current collector can employ a metal foil or a composite current collector. As an example of the metal foil, an aluminum 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 aluminum, an aluminum alloy, nickel, a nickel alloy, titanium, a titanium alloy, silver, and a 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.

[0157] The positive electrode film layer is generally formed by coating a positive electrode slurry on the positive electrode current collector, drying, and cold-pressing. The positive electrode slurry is generally formed by dispersing and uniformly stirring the positive electrode active material, the positive electrode conductive agent, the positive electrode binder, and any other components in a solvent. The solvent can be N-methyl pyrrolidone (NMP), but is not limited thereto.

[0158] [Negative electrode tab]

[0159] In some embodiments, the negative electrode tab can include a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector and including a negative electrode active material. For example, the negative electrode current collector has two surfaces opposite in the thickness direction thereof, and the negative electrode film layer is disposed on either one or both of the two opposite surfaces of the negative electrode current collector.

[0160] The negative active material can employ materials known in the art that are useful for secondary battery cells. As an example, the negative active material can 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. The silicon-based materials can include, but are not limited to, one or more of elemental silicon, silicon oxide, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy materials. The tin-based materials can include, but are not limited to, one or more of elemental tin, tin oxide, and tin alloy materials.

[0161] In some embodiments, the negative electrode film layer can further include a negative electrode conductive agent. As an example, the negative 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.

[0162] In some embodiments, the negative electrode film layer can further include a negative electrode binder. As an example, the negative electrode binder can include, but is not limited to, one or more of styrene butadiene rubber (SBR), water-soluble unsaturated resin SR-1B, water-based acrylic resin (e.g., polyacrylic acid PAA, polymethylacrylic acid PMAA, sodium polyacrylate PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS).

[0163] 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.

[0164] In some embodiments, the negative electrode current collector can employ a metal foil or a composite current collector. As an example of a 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.

[0165] 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 the negative active material, the negative electrode conductive agent, the 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.

[0166] The negative electrode tab does not exclude other additional functional layers in addition to the negative electrode film layer. For example, in some embodiments, the negative electrode tab also includes a conductive primer layer (e.g., composed of a conductive agent and a binder) sandwiched between the negative electrode current collector and the negative electrode film layer, disposed on the surface of the negative electrode current collector.

[0167] 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, etc. When the foamed metal is used 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.

[0168] [Electrolyte]

[0169] The electrolyte plays a role in conducting ions between the positive electrode tab and the negative electrode tab.

[0170] In some embodiments, the electrolyte employs an electrolyte solution, which includes an electrolyte salt and an organic solvent.

[0171] Taking a lithium battery cell as an example, 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 difluorooxalate borate (LiDFOB), lithium difluorophosphate (LiPO2F2), lithium difluorodioxalate phosphate (LiDFOP), and lithium tetrafluorooxalate phosphate (LiTFOP).

[0172] Taking a sodium battery cell as an example, 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 difluorooxalate borate (NaDFOB), sodium difluorophosphate (NaPO2F2), sodium difluorodioxalate phosphate (NaDFOP), and sodium tetrafluorooxalate phosphate (NaTFOP).

[0173] 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, diphenyl ether, crown ether.

[0174] 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.

[0175] Optionally, the additive can include one or more of fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,3-propane sultone (PS), and vinyl sulfate (DTD).

[0176] 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 after processes such as vacuum packaging, standing, and formation.

[0177] Examples

[0178] The present disclosure is more particularly described in the following examples, which are intended to be illustrative only, as numerous modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise noted, all parts, percentages, and ratios reported herein are based on mass, and all reagents used in the examples are commercially available or synthesized according to standard procedures, and used without further purification, and instruments used in the examples are commercially available.

[0179] A commercially available phenol and formaldehyde-based resol resin material was placed in a curing oven, the atmosphere was set to air atmosphere, the temperature was set to 120°C, and the temperature was maintained for 2h. After the end of the curing, the temperature of the curing oven was increased to 200°C, and the temperature was maintained for 4h. After the end of the two curing processes, the cured phenol formaldehyde resin material was taken out, naturally cooled in air, and then crushed, sand ground, sieved, and demagnetized to obtain phenol formaldehyde resin organic particles 1#.

[0180] The preparation methods of phenol formaldehyde resin organic particles 2# to 4# are similar to those of phenol formaldehyde resin organic particles 1#, except that the atmosphere and / or temperature of the curing oven are different, as shown in Table 1.

[0181] A commercially available phenol and formaldehyde-based resol resin material was placed in a curing oven, the atmosphere was set to air atmosphere, the temperature was set to 120°C, and the temperature was maintained for 2h. After the end of the curing, the temperature of the curing oven was increased to 200°C, and the temperature was maintained for 4h. After the end of the two curing processes, the cured phenol formaldehyde resin material was taken out, naturally cooled in air, and then crushed, sand ground, sieved, and demagnetized to obtain phenol formaldehyde resin organic particles 1#.

[0182] Phenolic resin-based organic particle performance test

[0183] (1) The initial thermal weight loss temperature T of the phenol formaldehyde resin organic particles 3d Test

[0184] An appropriate amount of sample (e.g., 5mg-15mg) was placed in an alumina crucible of a thermal gravimetric analyzer (TGA), leveled, and covered with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; temperature rising program: temperature rising rate 10°C / min, temperature range 35°C-600°C; the temperature corresponding to a 3% loss in sample mass relative to the initial mass was obtained from the test curve, which was the initial thermal weight loss temperature T 3d .

[0185] (2) Test of the melting point of the phenol formaldehyde resin organic particles

[0186] An appropriate amount of sample (e.g., 5mg-15mg) was placed in a differential scanning calorimeter (DSC) crucible, leveled, and covered with a crucible cover; parameter settings: nitrogen atmosphere, purge gas 60mL / min, protective gas 20mL / min; program settings: temperature rising rate 10°C / min from 25°C to 200°C, holding for 5min to eliminate thermal history, temperature lowering rate 10°C / min from 200°C to -40°C, and temperature rising rate 10°C / min from -40°C to 300°C. Whether the phenol formaldehyde resin organic particles have a melting point was determined by the DSC curve.

[0187] The phenolic resin organic particles 1# to 4# prepared above also meet the following characteristics: the phenolic resin organic particles are thermosetting propylene resins with no melting point.

[0188] Next, the phenolic resin organic particles prepared above were used in the separator to verify their impact on the performance of the separator and the secondary battery cells.

[0189] The manufacturing process of a secondary battery cell is as follows.

[0190] A commercially available 7μm thick polyethylene microporous membrane was used as the porous base membrane. The phenolic resin organic particles, dispersant sodium carboxymethyl cellulose, and binder polyacrylate were mixed evenly in deionized water at a solid mass ratio of 90:2:8 to obtain a slurry. The slurry was then... 2 The loading amount is uniformly coated on both surfaces of the porous base membrane, and the solvent is removed by drying to obtain the isolation membrane.

[0191] LiNi, the positive electrode active material 0.8 Co 0.1 Mn 0.1 O2, positive electrode binder polyvinylidene fluoride (PVDF), and positive electrode conductive agent carbon black are added to N-methylpyrrolidone (NMP) in a mass ratio of 97:2:1 and thoroughly mixed to prepare a positive electrode slurry. The positive electrode slurry is then uniformly coated onto the positive electrode current collector aluminum foil, and subsequently dried, cold-pressed, and slit to obtain the positive electrode sheet.

[0192] Artificial graphite (anode active material), acetylene black (anode conductive agent), styrene-butadiene rubber (SBR) (anode binder), and sodium carboxymethyl cellulose (thickener) were added to deionized water at a mass ratio of 96.0:1.4:1.5:1.1 and thoroughly mixed to prepare a cathode slurry. The cathode slurry was then uniformly coated onto copper foil (anode current collector), and subsequently dried, cold-pressed, and slit to obtain the cathode sheet.

[0193] At 25°C, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed in a volume ratio of 3:7 to obtain a mixed solvent. LiPF6 and fluoroethylene carbonate (FEC) were then dissolved in this mixed solvent to obtain the electrolyte. The concentration of LiPF6 was 1 mol / L. The mass fraction of FEC was 3%, based on the mass of the electrolyte.

[0194] The positive electrode, separator, and negative electrode are stacked, wound, and hot-pressed in sequence to obtain an electrode assembly. The electrode assembly is placed in a hard outer packaging, and the electrolyte prepared above is added. After processes such as encapsulation, standing, formation, and aging, a secondary battery cell is obtained.

[0195] Performance test

[0196] (1) Heat shrinkage rate test of the separator film

[0197] The heat shrinkage rate test of the separator film can refer to GB / T 36363-2018.

[0198] The separator film is punched into a sample with a width of 50 mm and a length of 100 mm by a punch press, and 5 parallel samples are placed on an A4 paper, and then the A4 paper with the samples is placed on a corrugated paper with a thickness of 1 mm to 5 mm.

[0199] The temperature of the air-blast oven is set to 130℃, and after the temperature reaches the set temperature and stabilizes for 60 min, the A4 paper placed on the corrugated paper is placed in the air-blast oven, and the timing starts, and after reaching the set time (1 h in the present disclosure), the length and width of the separator film are measured, and the values are marked as a and b respectively.

[0200] Heat shrinkage rate calculation: longitudinal (MD) heat shrinkage rate = [(100-a) / 100]x100%, transverse (TD) heat shrinkage rate = [(50-b) / 50]x100%, and the average value of 3 parallel samples is taken as the test result.

[0201] (2) Cycle performance test of the secondary battery cell

[0202] At 25℃, the secondary battery cell is charged at 1 / 3C constant current to 4.25V, then charged at 4.25V constant voltage to a current of 0.05C, and then rested for 5 min, and then discharged at 1 / 3C constant current to 2.8V, and the obtained discharge capacity is recorded as the initial capacity C0; the above charging and discharging steps are repeated, and at the same time the discharge capacity Cn of the secondary battery cell after the nth cycle is recorded, then the capacity retention rate Pn of the secondary battery cell after each cycle is (Cn / C0) x 100%. The cycle performance difference of the secondary battery cell can be reflected by the capacity retention rate of the secondary battery cell after 500 cycles.

[0203] Table 1

[0204]

[0205] From the above test results, it can be seen that the T 3d of the phenolic resin-based organic particles provided by the embodiments of the present disclosure are within the given range, which can make the separator film have a lower heat shrinkage rate, so that the secondary battery cell has higher thermal safety and better cycle performance.

[0206] Note that the present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration, function, and effect as the technical idea of the present disclosure are included in the technical scope of the present disclosure. Furthermore, various modifications that can be thought of by those skilled in the art, and other modes of embodiment constructed by combining part of the configurations of the embodiments, are also included in the scope of the present disclosure without departing from the spirit of the present disclosure.

Claims

1. A phenol-aldehyde resin-based organic particle, characterized by, The phenol-formaldehyde resin organic particles have an initial thermal weight loss temperature T 3d of 290°C to 346°C.

2. The phenol resin-based organic particle according to claim 1, characterized by, The phenolic resin-based organic particles have an initial thermal weight loss temperature T 3d is 310°C - 346°C.

3. The phenol-formaldehyde resin-based organic particles according to any one of claims 1 to 2, characterized in that, The phenolic resin-based organic particles have no melting point.

4. The phenol resin-based organic particles according to any one of claims 1 to 3, characterized by, The phenolic resin-based organic particles are thermosetting resol. 5.The phenolic resin-based organic particles according to any one of claims 1-4, wherein, The volume distribution particle size Dv50 of the phenolic resin-based organic particles is 200 nm-850 nm; and / or, The phenolic resin-based organic particles have a true density of 1.0 g / cm 3 -1.4 g / cm 3 . 6.A method for preparing phenolic resin-based organic particles, comprising the following steps: providing a resol phenolic resin-based material; curing the resol phenolic resin-based material at a first temperature and in a first atmosphere for a first time, and then curing at a second temperature and in a second atmosphere for a second time, wherein the first temperature is 80-160 ℃, and the second temperature is 180-270 ℃; then crushing to obtain the phenolic resin-based organic particles. 7.The method according to claim 6, wherein, the first atmosphere is an oxygen-containing atmosphere or an inert atmosphere, and the oxygen-containing atmosphere has an oxygen volume fraction of 5%-50%; and / or, the second atmosphere is an oxygen-containing atmosphere or an inert atmosphere, and the oxygen-containing atmosphere has an oxygen volume fraction of 5%-50%.

8. The method according to any one of claims 6-7, characterized in that, the first time is 1-3 h, and / or the second time is 1-5 h.

9. The method according to any one of claims 6-8, characterized in that, The method for preparing the resol phenolic resin-based material comprises the following steps: reacting a phenolic compound and an aldehyde compound under the catalysis of an alkaline substance to obtain the resol phenolic resin-based material. 10.The method according to claim 9, wherein, the phenolic compound comprises one or more of phenol, hydroquinone, resorcinol, catechol, cresol, and cardanol; and / or, the aldehyde compound comprises one or more of formaldehyde, paraformaldehyde, acetaldehyde, propyl aldehyde, n-butyl aldehyde, glyoxal, and furfural.

11. 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 layer comprises the phenolic resin-based organic particles according to any one of claims 1-5, or the phenolic resin-based organic particles prepared by the method according to any one of claims 6-10. 12.The separator according to claim 11, wherein, 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; and / or, the thickness of the coating layer is 0.5-5 μm; and / or, The areal density of the coating is 0.45 g / m 2 - 4.5 g / m 2 .

13. The separator membrane according to any one of claims 11-12, characterized in that, 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 2.

5. 14.The separator according to any one of claims 11-13, wherein, the longitudinal heat shrinkage of the separator is less than or equal to 2% when heated at 130 ℃ for 1 h; and / or, the transverse heat shrinkage of the separator is less than or equal to 2% when heated at 130 ℃ for 1 h.

15. A secondary battery cell, characterized by The separator according to any one of claims 11-14 is arranged between the positive electrode sheet and the negative electrode sheet.

16. A battery device characterized by comprising: The secondary battery device comprises a plurality of the secondary battery cells according to claim 15.

17. An electrical device, comprising: The secondary battery device comprises the secondary battery cell according to claim 15 or the battery device according to claim 16.

Images