Separator and method for manufacturing the same, battery, and power consumption device

Abstract

The present application discloses a separator and a manufacturing method thereof, a battery and a power consuming device, wherein the separator comprises a substrate and a coating formed on at least a part of the substrate, the coating comprises composite particles and an adhesive, the composite particles form protrusions on a surface of the coating, the composite particles comprise polyacrylate particles and inorganic particles, and inorganic particles are disposed between at least two of the polyacrylate particles, and the crosslinking degree a of the composite particles and the mass swelling degree b of the composite particles in an electrolyte satisfy a / b≧1 and a≧75%.

Description

Technical Field

[0001] This application belongs to the field of secondary battery technology, and specifically relates to a separator and its manufacturing method, as well as a battery and a power consumption device.

Background Art

[0002] In the manufacturing process of the battery core of an electrochemical device, the electrode plate and the separator are inevitably displaced during transfer. In the case of a minor displacement, the electrode plate becomes wrinkled after full charge, seriously affecting the kinetic performance, reducing the safety performance of the battery core. In the case of a severe displacement, the electrode plates come into contact with each other, resulting in the abandonment of the dry battery core. Therefore, generally, an adhesive coating is applied to the separator, but the conventional adhesive coating is likely to cause relatively low kinetic and safety performance of the battery.

Summary of the Invention

[0003] In view of the technical problems existing in the background art, the purpose of this application is to provide a separator to improve the kinetic and safety performance of conventional batteries.

[0004] To achieve the above object, the first aspect of this application provides a separator, which includes a substrate and a coating formed on at least a part of the surface of the substrate. The coating includes composite particles and an adhesive. The composite particles form protrusions on the coating surface. The composite particles include polyacrylate particles and inorganic particles. There are inorganic particles between at least two of the polyacrylate particles. The crosslinking degree a of the composite particles and its mass swelling degree b in the electrolyte satisfy a / b≧1 and a≧75%.

[0005] Compared with the prior art, the present application has at least the following beneficial effects. The separator coating of the present application contains composite particles and an adhesive. The composite particles include polyacrylate particles and inorganic particles. There are inorganic particles between at least two polyacrylate particles, avoiding adhesion during high-temperature granulation of the composite particles, improving the ion conduction ability of the separator, improving the compression elastic modulus of the composite particles, and enabling the adhesion between the separator and the electrode plate to be relatively appropriate. During transportation, the adhesion force between the separators does not become excessive, thereby not affecting the subsequent use of the separators. At the same time, the crosslinking degree a of the composite particles adopted in the present application and its mass swelling degree b in the electrolyte satisfy a / b≥1 and a≥75%. On the one hand, the composite particles satisfying this crosslinking degree condition have an appropriate compression elastic modulus, reducing the situation where the protrusions on the separator coating block the anode surface with volume expansion during the cycle, and improving the cycle life of the battery. On the other hand, this composite particle does not cause excessive swelling in the electrolyte and consume excessive electrolyte, and reduces the situation where the volume of the composite particle expands excessively and blocks the separator holes. Also, when the battery undergoes thermal runaway and high temperature occurs, the protrusions formed by the composite particles on the coating surface can form a large-area adhesive film structure to reduce or block the ion transmission channels, delaying the thermal diffusion of the battery, thereby effectively improving the cycle performance and high-temperature safety performance of the battery.

[0006] In some embodiments of the present application, the a / b value is 1-2.1, preferably 1-1.4. Thereby, the safety performance and kinetic performance of the battery can be improved.

[0007] In some embodiments of the present application, the Dv50 of the composite particles is ≥2.5 μm, preferably 2.5 μm-10 μm, more preferably 3 μm-8 μm. Thereby, it is advantageous to form a protrusion structure on the coating surface, thereby improving the kinetic performance of the battery core.

[0008] In some embodiments of the present application, there are first aggregates among the polyacrylate particles, and the first aggregates include at least two of the inorganic particles. Thereby, the kinetic performance of the battery can be enhanced.

[0009] In some embodiments of the present application, 0.01 μm ≤ Dv50 of the first aggregates ≤ Dv10 of the composite particles. Thereby, the compressive elastic modulus of the separator can be enhanced.

[0010] In some embodiments of the present application, the composite particles include inorganic particles in the form of primary particles.

[0011] In some embodiments of the present application, Dv50 of the inorganic particles in the form of primary particles is 0.01 μm - 1 μm, preferably 0.5 μm - 1 μm. Thereby, it can be ensured that no fusion occurs during the production of the composite particles to block the separator ion transport channels.

[0012] In some embodiments of the present application, the composite particles include second aggregates, and the second aggregates include at least two of the polyacrylate particles.

[0013] In some embodiments of the present application, Dv50 of the second aggregates is 0.3 μm - 5 μm, preferably 1 μm - 2 μm.

[0014] In some embodiments of the present application, the polyacrylate particles include polyacrylate particles in the form of primary particles and / or polyacrylate particles in the form of secondary particles.

[0015] In some embodiments of the present application, Dv50 of the polyacrylate particles in the form of primary particles is 50 nm - 400 nm, preferably 100 nm - 200 nm. Thereby, the ion conduction ability of the entire separator coating can be enhanced, the resistance of the separator can be reduced, and the kinetic performance of the battery core can be enhanced.

[0016] In some embodiments of the present application, the Dv50 of the polyacrylate particles in the form of secondary particles is 2 μm - 15 μm, preferably 5 μm - 8 μm. Thereby, a buffer space for releasing the stress between the electrode plates can be provided, and breakage of the bending angle of the wound battery core due to stress accumulation can be prevented.

[0017] In some embodiments of the present application, the content of the inorganic particles in the composite particles is 1 wt% - 50 wt%, optionally 1 wt% - 40 wt%, further optionally 2 wt% - 15 wt%, and most preferably 5 wt% - 15 wt%. Thereby, the separator obtains an appropriate compression elastic modulus.

[0018] In some embodiments of the present application, the height of both sides of the protrusion is 15 μm - 60 μm. Thereby, the battery safety can be improved and the kinetic performance of the battery core can be improved at the same time.

[0019] In some embodiments of the present application, the surface of the protrusion has the first aggregate. Thereby, the kinetic performance of the battery can be improved.

[0020] In some embodiments of the present application, the glass transition temperature of the polyacrylate particles is 20°C - 80°C, preferably 25°C - 65°C.

[0021] In some embodiments of the present application, the area coverage rate of the coating of the composite particles is 10% - 25%. Thereby, the adhesion between the coating of the separator and the electrode plate can be made appropriate, and the kinetic performance of the battery core can be improved.

[0022] In some embodiments of the present application, the inorganic particles include one or more of silicon, aluminum, calcium, zinc, magnesium oxides and sodium sulfate, sodium benzoate, calcium carbonate and its modified materials, and are selectively one or more of silicon dioxide, silica sol, aluminum oxide, zinc oxide, magnesium oxide, sodium benzoate, and further selectively one or more of fumed silicon dioxide, silicon fine powder, aluminum oxide, sodium benzoate.

[0023] In some embodiments of the present application, the adhesive includes an adhesive polymer and a plasticizer. Thereby, the pressure-sensitive property of the separator can be improved, and the kinetic performance of the battery core can be improved.

[0024] In some embodiments of the present application, the adhesive polymer includes a copolymer formed by at least one of the following first monomers, at least one of the second monomers, at least one of the third monomers and at least one of the reactive dispersants, that is, First monomer: including acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylolacrylamide, acrylamide, styrene, acrylonitrile, Second monomer: including C4-C22 alkyl acrylate, isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl acrylate (isooctyl), cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, ethylenoureaethyl methacrylate, methacrylic acid acrylate, dicyclopentenyl oxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate. Third monomer: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, 3-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethyl(meth)acrylamide, diacetoneacrylamide, ethyl acetoacetate methacrylate, divinylbenzene, epoxy resin with an epoxy value of 0.35 - 0.50, including divinylbenzene, Reactive dispersant: including polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, polyvinyl alcohol.

[0025] Thereby, appropriate swelling and adhesion of the adhesive polymer are ensured, and it is guaranteed that the adhesive polymer has appropriate swelling, pressure sensitivity, and adhesion performance, as well as an appropriate elastic modulus, and the shaping effect, kinetic performance, and safety performance of the battery core can be guaranteed.

[0026] In some embodiments of the present application, the plasticizer includes at least one of glycerol C4-C10 alkyldiethers, glycerol C4-C10 alkylmonoethers, glycerol C4-C10 carboxylic acid monoesters, glycerol C4-C10 carboxylic acid diesters, propylene glycol C4-C10 alkylmonoethers, and glycerol. In some embodiments of the present application, the mass ratio of the solid content in the composite particles to the adhesive is (80 - 90):(5 - 20), preferably (85 - 90):(8 - 15). Thereby, the cycle performance and safety performance of the battery can be improved.

[0027] In some embodiments of the present application, the coating further includes organic particles, and the organic particles include polytetrafluoroethylene particles, polytrifluorochloroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of fluorine-containing alkenyl monomer units and ethylene monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylate monomer units, and at least one of modified compound particles of each of the above homopolymers or copolymers. The organic particles and the composite particles form protrusions on the coating surface. Thereby, the cycle performance and safety performance of the battery can be improved.

[0028] In some embodiments of the present application, the organic particles form a third aggregate.

[0029] In some embodiments of the present application, the Dv50 of the third aggregate is 5 μm - 30 μm, preferably 5.0 μm - 12 μm.

[0030] In some embodiments of the present application, the third aggregate includes organic particles in the form of primary particles, and there are gaps between two adjacent organic particles. Thereby, the ionic conductivity of the separator can be improved.

[0031] In some embodiments of the present application, the Dv50 of the organic particles in the form of primary particles is 50 nm - 400 nm, preferably 100 nm - 200 nm.

[0032] In some embodiments of the present application, the mass ratio of the composite particles to the organic particles is (20 - 90):(0 - 70), preferably (45 - 90):(0 - 45). Thereby, the battery cost can be reduced while enhancing its safety performance and cycle performance.

[0033] The second aspect of the present application provides a method for manufacturing a separator, the method including: step (1) of providing a substrate; and step (2) of forming a coating containing composite particles and an adhesive on at least a part of the surface of the substrate, wherein the composite particles form protrusions on the coating surface, the composite particles include polyacrylate particles and inorganic particles, inorganic particles are present between at least two of the polyacrylate particles, and the degree of crosslinking a of the composite particles and its mass swelling degree b in the electrolyte satisfy a / b≥1 and a≥75%.

[0034] Thereby, this separator has an excellent compression elastic modulus and appropriate adhesiveness with the electrode plate, thereby enhancing the cycle performance of the battery and improving its safety performance at the same time.

[0035] The third aspect of the present application provides a battery, the battery including a separator according to the first aspect of the present application or a separator manufactured by the method of the second aspect of the present application. Since the battery of the present application includes the above-mentioned separator according to the present application or a separator manufactured by the above method, it has excellent safety performance and kinetic performance.

[0036] The fourth aspect of the present application provides a power consumption device, the device including a battery according to the third aspect of the present application, the battery being used to provide electrical energy. Since the power consumption device of the present application includes the above-mentioned battery according to the present application, it has at least the same advantages as the above-mentioned battery.

Brief Description of the Drawings

[0037] To more clearly illustrate the technical solution of the present application, the drawings used in the present application are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can also obtain other drawings based on the drawings on the premise of not paying creative labor.

[0038]

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Embodiments for Carrying Out the Invention

[0039] Hereinafter, the present application will be further described while combining embodiments for carrying out the invention. It should be understood that these specific embodiments are used only for explaining the present application and are not intended to limit the scope of the present application.

[0040] For the sake of brevity, this specification specifically discloses only some numerical ranges. However, any lower limit may form a range not explicitly described in combination with any upper limit, and any lower limit may form a range not explicitly described in combination with other lower limits. Similarly, any upper limit may form a range not explicitly described in combination with other arbitrary upper limits. Note that each point or single numerical value disclosed alone may also form a range not explicitly described in combination with any other point or single numerical value as a lower limit or upper limit or in combination with other lower limits or upper limits.

[0041] In the description of this specification, unless otherwise specified, the term "or" is inclusive. That is, the phrase "A or B" represents "A, B, or both A and B". More specifically, any of the conditions where A is true (or exists) and B is false (or does not exist), where A is false (or does not exist) but B is true (or exists), and where both A and B are true (or exist) satisfy "A or B".

[0042] In the description of this specification, it should be noted that, unless otherwise specified, "above" and "below" include this number, and "plural" in "one or more" means two or more.

[0043] Unless otherwise stated, the terms used in this application have the meanings known to those skilled in the art. Unless otherwise stated, the numerical values of each parameter mentioned in this application can be measured by various measurement methods commonly used in the art (for example, it can be tested by the method according to the examples of this application).

[0044] The examples of this application provide a separator, which includes a substrate and a coating formed on at least a part of the surface of the substrate. The coating includes composite particles and an adhesive. The composite particles form protrusions on the coating surface. The composite particles include polyacrylate particles and inorganic particles. There are inorganic particles between at least two of the polyacrylate particles. The crosslinking degree a of the composite particles and its mass swelling degree b in the electrolyte satisfy a / b≧1 and a≧75%.

[0045] It should be noted that the formation of the coating on at least a part of the surface of the substrate should be understood as either the coating directly contacting the surface of the substrate, so-called "direct contact", or there being another layer between the substrate surface and the coating, so-called "indirect contact". At the same time, "there are inorganic particles between at least two of the polyacrylate particles and the composite particles form protrusions on the coating surface" means that by cutting the separator along its thickness direction and scanning the cross-section of the separator coating using a scanning electron microscope (SEM), as can be seen from the SEM diagram, the composite particles contain polyacrylate particles and inorganic particles, and there are inorganic particles between some of the polyacrylate particles and the composite particles can form protrusions on the coating surface.

[0046] Specifically, it is tested using a ZEISS Sigma300 scanning electron microscope and tested according to the following step operations. First, the measurement separator is cut into a 6 mm × 6 mm measurement sample, the measurement sample is sandwiched between two conductive and thermally conductive copper foils, and the measurement sample and the copper foil are adhesively fixed with double-sided tape. The smaller the gap between the measurement sample and the copper foil, the better. Press with a flat iron block of a certain 400 g for 1 hour, and then trim the edge with scissors and attach it to a sample stage with a conductive adhesive, with the sample slightly protruding from the edge of the sample stage. Then put the sample stage into the sample rack, lock and fix it, turn on the power of the IB-19500CP argon ion cross-section polishing instrument and evacuate to 10 Pa -4 Pa, set the argon gas flow rate to 0.15 MPa, the voltage to 8 KV, and the polishing time to 2 hours, adjust the sample stage to the rocking mode and start polishing. After polishing, obtain the ion-polished cross-sectional morphology (CP) image of the measurement sample using a ZEISS Sigma300 scanning electron microscope.

[0047] According to one example, the production of the composite particles of the present application may refer to the following steps.

[0048] (1) Provide a polymer monomer for producing polyacrylate particles, polymerize the polymer monomer to obtain a polyacrylate polymer, (2) Add a solvent and inorganic particles to the polyacrylate polymer obtained in step (1), and obtain a mixed slurry after stirring, (3) Dry the mixed slurry in step (2) to remove the solvent, and obtain the composite particles described in the present application after polishing and grinding.

[0049] It should be noted that the polymerization of the polymer monomer may be carried out using a polymerization method commonly used in the art. For example, it may be polymerized using an emulsion polymerization or suspension polymerization method.

[0050] In some embodiments, in step (1), additives such as an emulsifier, such as sodium lauryl sulfate, and a polymerization initiator, such as ammonium persulfate, may be added to the polymerization system of the polymer monomer.

[0051] In some embodiments, in step (1), the polymer monomer for producing polyacrylate particles is at least having at least one ester bond, and optionally methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, isobornyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, vinyl acetate, trifluoroethyl methacrylate, glycidyl methacrylate or trimethylolpropane triacrylate, and further optionally one or more of methyl methacrylate, lauryl acrylate, lauryl methacrylate or trimethylolpropane triacrylate as a first polymer monomer, and having at least one cyano bond, and being selectively one or more of acrylonitrile, methacrylonitrile, and ethacrylonitrile, and further selectively one or more of acrylonitrile and methacrylonitrile, and a second polymer monomer, having at least one amide bond, and being selectively one or more of acrylamide, N-methylol acrylamide, and N-butoxymethacrylamide, and further selectively one or more of acrylamide and N-methylol acrylamide, and a third polymer monomer, and including a polymer monomer among them.

[0052] Thereby, the polyacrylate particles are formed by polymerizing at least the above three types of polymer monomers, and the separator can obtain appropriate adhesiveness with the electrode plate and improve the kinetic performance of the battery.

[0053] In some embodiments, the weight ratio of the first polymer monomer, the second polymer monomer, and the third polymer monomer in the formed polyacrylate particles is (45-70):(10-25):(10-35), such as (50-70):(10-25):(10-35), (55-70):(10-25):(10-35), (60-70):(10-25):(10-35), (65-70):(10-25):(10-35), (45-70):(15-25):(10-35), (45-70):(20-25):(10-35), (45-70):(22-25):(10-35), (45-70):(10-25):(15-35), (45-70):(10-25):(20-35), (45-70):(10-25):(25-35), (45-70):(10-25):(30-35), (45-70):(10-25):(32-35), etc. Thereby, when the polyacrylate particles are polymerized by adopting the polymer monomers in the above ratios, the glass transition temperature of the polyacrylate particles can meet the requirement of 20°C - 80°C.

[0054] In some embodiments, in step (2), the inorganic particles include one or more of silicon, aluminum, calcium, zinc, magnesium oxides and sodium sulfate, sodium benzoate, calcium carbonate and its modified materials, and are selectively one or more of silicon dioxide, silica sol, aluminum oxide, zinc oxide, magnesium oxide, sodium benzoate, and further selectively one or more of fumed silicon dioxide, silicon fine powder, aluminum oxide, sodium benzoate.

[0055] In this application, the "crosslinking degree a of the composite particles" refers to the crosslinking degree of the polyacrylate particles in the composite particles, and the test method may adopt the following steps.

[0056] (1) Stack two layers of weighing paper and weigh 6 g of composite particles (the weighing balance adopts a Uni Bloc SHIMADZU AUY220 one-millionth balance), (2) Place the weighed composite particles in a vacuum oven at 105°C (the vacuum oven adopts a Lijia LDZF-6090 with a size of 450*450*450 RT~250°C) and dry for 6 h, (3) Stack two layers of medium-speed filter paper (the medium-speed filter paper adopts a Nova quantitative medium-speed filter paper), number them, and place them in a vacuum oven at 105°C (the vacuum oven adopts a Lijia LDZF-6090 with a size of 450*450*450 RT~250°C) and dry for 6 h, (4) Immediately after taking out the composite particles and the weighing paper from the vacuum oven, package them immediately with a seal bag to prevent water absorption, (5) Immediately after taking out the medium-speed filter paper from the vacuum oven, put it into a self-sealing bag and weigh it, record the total weight m1 of the medium-speed filter paper and the self-sealing bag, and leave four decimal places for the weight value, (6) Pour the composite particles obtained in step (4) into a small crusher (the crusher adopts Baixin LG-01, with a power of 350 W, a fineness of 30~300 mesh, a rotation speed of 2500 r / m, and a crushing capacity of 500 g / m), cover it, tighten it, (7) Turn on the power, turn on the power switch, count for 30 S with a stopwatch, and then turn off the power switch, (8) The crusher is left standing for 5 minutes. Once the powder in the crusher has settled, turn the lid of the crusher to open it. The sample should be in a uniformly powdered form. (9) Transfer the crushed sample to a self-sealing bag using a brush and seal it immediately. (10) After peeling the centrifuge tube and its lid on the balance, take out the sample bag from the drying dish, pour about 2 ± 0.2 g of the sample into the centrifuge tube, immediately cover the centrifuge tube, and weigh the actual weight m2 of the sample. (11) Add 50 ml of dimethyl carbonate (DMC) according to the scale on the 50 ml centrifuge tube. (12) Transfer the centrifuge tube to an oven at 60 °C (the oven uses Boxun GZX-9146MBE, with a capacity of 129 L, RT + 5 °C to 300 °C) and keep it warm for 12 hours. (13) After taking the centrifuge tube out of the oven, pour the sample onto medium-speed filter paper to filter the solution and leave the filtrate. (14) Rinse the centrifuge tube with a large amount of DMC solution to prevent the sample from remaining in the centrifuge tube. (15) Dry the filtrate in an oven at 105 °C for 2 hours. (16) After the sample has been calcined, put the sample into the corresponding self-sealing bag and weigh it. (17) Clear the scale, weigh the total mass of the filtrate, medium-speed filter paper and self-sealing bag, and record the mass m3. Crosslinking degree Calculate the crosslinking degree a of the composite particles according to TIFF0007701991000001.tif14168.

[0057] In this application, the "mass swelling degree b of the composite particles" refers to the mass swelling degree of the polyacrylate particles in the composite particles, and its test method may adopt the following steps.

[0058] (1) Dissolution: Take 10 g of composite particle powder and 90 g of N-methylpyrrolidone (NMP), mix them, and stir at 40 °C for 7 hours to dissolve. (2) Manufacture of the adhesive film: Place the stirred composite particle powder adhesive solution in a 250 mL beaker, bake it at a temperature of 70 °C for 8 days to obtain a dried adhesive film. (3) Swelling Rate Test: Take an adhesive film of about 3 g in size after drying. The thickness of the adhesive film is 2 mm. Weigh its exact mass as M1. Immerse it in an electrolyte (the mass ratio of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in the electrolyte solvent is 3:5:2, and the electrolyte solvent and lithium hexafluorophosphate (LiPF6) are placed in a 1 mol / L electrolyte), place it in an oven at 70 °C for baking. After 24 h, take out the sample piece, let it stand for 1 h, then wipe it clean and weigh its mass M2. The mass swelling degree = Calculate the mass swelling degree b of the composite particles according to TIFF0007701991000002.tif13168.

[0059] While not wishing to be bound by any theory, as a result of a lot of research, the inventors have found that in the prior art, generally, the misalignment between the electrode plate and the separator is reduced by coating an adhesive coating on the separator substrate. However, the adhesive force of the conventional adhesive coating is too large, and the adhesion between the separator and the electrode plate is too strong, which reduces the kinetic performance of the battery. At the same time, the relatively large adhesive force of the adhesive coating also makes the adhesive force between the separators relatively large, which is disadvantageous for the subsequent use of the separator. At the same time, because the compression elastic modulus of the adhesive coating is relatively low, when the battery core is compressed by an external force, the adhesive coating is likely to collapse, which may block the separator holes. In addition, the adhesive coating is likely to swell in the electrolyte, consuming excessive electrolyte. The separator coating of the present application contains composite particles and an adhesive. The composite particles are adhered to the substrate through the adhesive. The composite particles contain polyacrylate particles and inorganic particles. There are inorganic particles between at least two polyacrylate particles in the composite particles. On the one hand, the composite particles contain polyacrylate particles and inorganic particles. There are inorganic particles between at least two polyacrylate particles in the composite particles. Due to the presence of inorganic particles in the composite particles, the polyacrylate particles do not adhere to each other during the high-temperature treatment of the granulation process. However, when the adhered polyacrylate particles are used in the separator coating, ion transmission is inhibited, reducing the ion conduction ability of the separator. On the other hand, since the polyacrylate particles themselves have a relatively low compression elastic modulus, when used alone in the separator coating, they are likely to block the separator holes under the action of pressure, and then block the anode surface, reducing ion conduction and the kinetic performance of the battery. However, by installing inorganic particles between the polyacrylate particles, the compression elastic modulus can be improved, ensuring that the kinetic performance of the separator and the anode is not affected by this composite particle, thereby enhancing the kinetic performance of the battery.Meanwhile, for the degree of crosslinking a of the composite particles employed in the present application and their mass swelling degree b in the electrolyte, a / b ≥ 1 and a ≥ 75% are satisfied. On the one hand, the composite particles satisfying this crosslinking degree condition have an appropriate compression elastic modulus, reducing the situation where the protrusions on the separator coating block the anode surface with volume expansion during the cycle, and can improve the cycle life of the battery. On the other hand, excessive swelling of this composite particle in the electrolyte does not occur to consume excessive electrolyte, and the situation where the volume of the composite particle expands excessively to block the separator holes is reduced. Further, the composite particles form protrusions on the surface of the base material or the coating, and the separator contacts the electrode plate through these protrusions. On the one hand, during winding, the protrusions provide an appropriate space to release stress, preventing damage to the electrode plate and improving safety. On the other hand, a gap is left between the separator and the electrode plate, which is advantageous for the flow and infiltration of the electrolyte, improving the kinetic performance of the battery core. With the combined action of the above conditions, an appropriate adhesive force is possessed between the separator and the electrode plate, thereby improving the kinetic performance of the battery. When the battery undergoes thermal runaway and high temperature occurs, the protrusions can form a large-area adhesive film structure to reduce or block the ion transmission channel, delaying the thermal diffusion of the battery, thereby effectively improving the cycle performance and safety performance at high temperature of the battery.

[0060] As a result of in-depth research, the inventor has discovered that in addition to the separator of the present application satisfying the above conditions, when further selectively satisfying one or several of the following conditions, the performance of the battery can be further improved.

[0061] In some embodiments, for the crosslinking degree a of the composite particles and the mass swelling degree b thereof in the electrolyte, it satisfies that a / b is 1 - 2.1, for example, 1 - 2, 1 - 1.8, 1 - 1.6, 1 - 1.4, 1 - 1.2, etc. On the one hand, the composite particles satisfying this crosslinking degree condition have an appropriate compression elastic modulus, reducing the situation where the protrusions on the separator coating block the anode surface with volume expansion during cycling, and can improve the cycle life of the battery. On the other hand, excessive swelling of this composite particle in the electrolyte does not occur to consume excessive electrolyte, and the situation where the volume of the composite particle expands excessively to block the separator holes is reduced. In some other embodiments, for the crosslinking degree a of the composite particles and the mass swelling degree b thereof in the electrolyte, it satisfies that a / b is 1 - 1.4.

[0062] In some embodiments, for the separator of the present application, the Dv50 of the composite particles is ≥2.5 μm, for example, 2.5 μm - 10 μm, 2.5 μm - 8 μm, 2.5 μm - 6 μm, 2.5 μm - 5 μm, 2.5 μm - 4 μm, 2.5 μm - 3 μm, etc. Thereby, on the one hand, the composite particles satisfying within this Dv50 range can provide an appropriate adhesion force between the separator coating and the electrode plate. On the other hand, it is advantageous for forming a protrusion structure on the coating surface, thereby improving the kinetic performance of the battery core. In some other embodiments, for the separator of the present application, the Dv50 of the composite particles is 3 μm - 8 μm.

[0063] In some embodiments, in the separator of the present application, referring to FIG. 1, between the polyacrylate particles, there is a first aggregate, and the first aggregate contains at least two inorganic particles. Thereby, on the one hand, the composite particles are not made too soft, thereby ensuring that when the battery expands or is subjected to a relatively large external force, the interaction between the composite particles and the electrode plate and between the composite particles and the substrate is appropriate, thereby improving the kinetic performance of the battery. On the other hand, it can be ensured that the composite particles do not fuse during production to block the ion transport channels, and when there is a first aggregate formed by the inorganic particle substance inside or on the surface of the composite particles, in the case of high temperature, for example, ≥ 45°C and a state of receiving force ≥ 0.4 MPa, by ensuring that the spherical bodies of the composite particles do not soften and collapse, it is ensured that the interaction between the composite particles and the electrode plate and between the composite particles and the separator is appropriate, thereby suppressing the deterioration of the cycle performance of the battery and further improving the kinetic performance of the battery.

[0064] In some embodiments, 0.01 μm ≤ Dv50 of the first aggregate ≤ Dv10 of the composite particles. Thereby, the compression elastic modulus of the separator can be increased.

[0065] In some embodiments, in the separator of the present application, the composite particles contain inorganic particles in the form of primary particles. Further, Dv50 of the inorganic particles in the form of primary particles is 0.01 μm - 1 μm, for example, 0.01 μm - 0.8 μm, 0.05 μm - 1 μm, 0.1 μm - 1 μm, 0.2 μm - 1 μm, 0.3 μm - 1 μm, 0.4 μm - 1 μm, 0.5 μm - 1 μm, 0.6 μm - 1 μm, 0.7 μm - 1 μm, 0.8 μm - 1 μm, 0.9 μm - 1 μm, etc. Thereby, the inorganic particles satisfying this Dv50 can enable the separator to obtain an appropriate compression elastic modulus, thereby enhancing the kinetic performance of the battery. In some other embodiments, Dv50 of the inorganic particles in the form of primary particles is 0.5 μm - 1 μm. Thereby, the kinetic performance of the battery can be enhanced.

[0066] It should be noted that the primary particles and secondary particles have meanings known in the art. The primary particles are particles that do not form an aggregated state. The secondary particles are particles in an aggregated state formed by aggregation of two or more primary particles.

[0067] In some embodiments, in the separator of the present application, the composite particles include a second aggregate, and the second aggregate includes at least two of the polyacrylate particles. Thereby, the composite particles are not made too soft, thereby ensuring that the battery expands or under a relatively large external force, the interaction between the composite particles and the electrode plate and between the composite particles and the base material is appropriate, thereby improving the kinetic performance of the battery. Further, the Dv50 of the second aggregate is 0.3 μm - 5 μm, for example, 0.5 μm - 5 μm, 0.7 μm - 4.5 μm, 1 μm - 4 μm, 1.3 μm - 3.5 μm, 1.5 μm - 3.2 μm, 1.7 μm - 3 μm, 2 μm - 2.8 μm, 2 μm - 2.5 μm, 5 μm - 10 μm, 5 μm - 9 μm, 5 μm - 8 μm, 5 μm - 7 μm, 5 μm - 6 μm, etc. In some other embodiments, the Dv50 of the second aggregate is 1 m - 2 μm.

[0068] In some embodiments, in the composite particles of the present application, the polyacrylate particles include polyacrylate particles in the form of primary particles and / or polyacrylate particles in the form of secondary particles. Here, the Dv50 of the polyacrylate particles in the form of primary particles is 50 nm - 400 nm, for example, 50 nm - 375 nm, 75 nm - 375 nm, 100 nm - 350 nm, 125 nm - 325 nm, 150 nm - 300 nm, 175 nm - 275 nm, 200 nm - 250 nm, 200 nm - 225 nm, etc. In some other embodiments, the Dv50 of the polyacrylate particles in the form of primary particles is 100 nm - 200 nm. The Dv50 of the polyacrylate particles in the form of secondary particles is 2 μm - 15 μm, for example, 3 μm - 15 μm, 4 μm - 12 μm, 5 μm - 10 μm, 5 μm - 8 μm, 5 μm - 7 μm, 5 μm - 6 μm, etc.

[0069] In some embodiments, the content of the inorganic particles in the composite particles is 1 wt% - 50 wt%, for example, 1 wt% - 48 wt%, 1 wt% - 45 wt%, 1 wt% - 40 wt%, 1 wt% - 35 wt%, 1 wt% - 30 wt%, 1 wt% - 25 wt%, 1 wt% - 20 wt%, 1 wt% - 15 wt%, 2 wt% - 15 wt%, 3 wt% - 15 wt%, 4 wt% - 15 wt%, 5 wt% - 15 wt%, 7 wt% - 15 wt%, 10 wt% - 15 wt%, 12 wt% - 15 wt%, etc. By controlling the content of the inorganic particles in the composite particles within the above content range, on the one hand, the polyacrylate particles do not adhere to each other during the high-temperature treatment of the granulation process, improving the ion conduction ability of the separator. On the other hand, the separator has an appropriate compression elastic modulus, ensuring that there is an appropriate acting force between the separator coating and the anode when the battery module is under force.

[0070] In some embodiments, in the separator of the present application, the glass transition temperature of the polyacrylate particles in the composite particles is 20°C - 80°C, for example, 25°C - 75°C, 30°C - 70°C, 35°C - 65°C, 40°C - 60°C, 45°C - 55°C, 50°C - 55°C. When the glass transition temperature of the polyacrylate particles satisfies the above temperature, the composite particles can withstand the swelling of the electrolyte. On the one hand, without consuming excessive electrolyte, the residual monomers are not foamed by the electrolyte to block the separator, thus not affecting the kinetic performance of the battery core. On the other hand, the adhesion performance between the separator and the electrode plate does not decrease significantly, and the electrode plate is not easily pressured by the composite particles to affect the safety performance of the battery. In some other embodiments, the glass transition temperature of the polyacrylate particles in the composite particles is 25°C - 65°C.

[0071] According to some examples, the test method for the glass transition temperature of the polyacrylate particles may be measured by a method commonly used in the art. For example, it may be tested by differential scanning calorimetry with reference to GB / T19466.2, with a heating rate of 10°C / min and an air atmosphere.

[0072] In some embodiments, the area coverage rate of the coating on the composite particles is 10% - 25%, such as 12% - 25%, 15% - 25%, 17% - 25%, 19% - 25%, 20% - 25%, 22% - 25%, etc. The inventor has found that if the area coverage rate of the coating on the composite particles is too low (less than 10%), the coating adhesion will severely decrease, problems of the soft battery core will occur in the bare battery core, and it will not be able to meet the requirement of shaping and putting it into the shell. If the area coverage rate of the coating on the composite particles is too high (more than 25%), the adhesion of the battery core will be too large, which will seriously affect the injection efficiency, and at the same time, the possibility of film formation of the adhesive substance during the cycle of the battery core will increase, blocking the separator holes and deteriorating the kinetic performance. In some other embodiments, the area coverage rate of the coating on the composite particles is 15% - 20%.

[0073] According to some examples, the area coverage rate of the coating on the composite particles is obtained by using the coating rate testing device of Guangdong Jitai Intelligent Equipment Co., Ltd.

[0074] In some embodiments, referring to FIG. 2, protrusions are formed on the separator coating surface of the present application, and the height of both sides of this protrusion is 15μm - 60μm, such as 15μm - 58μm, 16μm - 56μm, 18μm - 55μm, 20μm - 52μm, 22μm - 40μm, 25μm - 40μm, 25μm - 38μm, 25μm - 36μm, 28μm - 35μm, 30μm - 32μm, etc. Thereby, the protrusions within this height range can, on the one hand, provide an appropriate space between the separator and the electrode plate to release stress, prevent damage during the winding of the electrode plate, and improve safety. On the other hand, an appropriate gap is left between the separator and the electrode plate, which is beneficial to the flow and infiltration of the electrolyte and improves the kinetic performance of the battery core. Furthermore, the surface of the protrusion has a first aggregate. Thereby, this protrusion can provide appropriate adhesion between the separator and the electrode plate, thereby enhancing the kinetic performance of the battery.

[0075] Specifically, coatings are formed on two opposing surfaces of the base material. The sum of the protrusion heights on the coatings on both sides is the height of both sides of the protrusion. For the test method of the height of both sides of the protrusion, referring to Figure 3, first, the negative electrode plate, separator, and positive electrode plate are stacked in order with the battery core and then wound (the outermost layer of the battery core ends with the convex surface of the positive electrode plate). Then, a CT device (ZEISS - 1500) is used to scan a position 15 ± 1 mm below the edge of the negative electrode plate at the bending angle of the wound battery core. Sampling is performed along the horizontal & inclination angle (30 - 45°) in the obtained CT diagram, a line is drawn in the direction with the largest gap, the inner 5 - fold sampling position is from the convex surface of the innermost positive electrode plate to the convex surface of the 5th positive electrode plate, and the 4 - fold average value is taken. The sampling position after 6 - fold is from the convex surface of the inner positive electrode plate to the convex surface of the outer positive electrode plate, including taking values every 5 - fold.

[0076] Average value of the gap of the inner 5 layers = [CT measurement distance - 4 * thickness of the negative electrode plate after cold pressing * (1 + rebound rate of the negative electrode plate) - 4 * thickness of the positive electrode plate after cold pressing * (1 + rebound rate of the positive electrode plate) - 8 * thickness of the separator] / 8 Average value of the gap after the inner 6 - 10 layers and later = [CT measurement distance - 5 * thickness of the negative electrode plate after cold pressing * (1 + rebound rate of the negative electrode plate) - 5 * thickness of the positive electrode plate after cold pressing * (1 + rebound rate of the positive electrode plate) - 10 * thickness of the separator] / 10 Here, the rebound rate of the negative electrode plate = (thickness of the negative electrode plate before shell insertion - thickness of the negative electrode plate after cold pressing) / thickness of the negative electrode plate after cold pressing, The rebound rate of the positive electrode plate = (thickness of the positive electrode plate before shell insertion - thickness of the positive electrode plate after cold pressing) / thickness of the positive electrode plate after cold pressing, The height of both sides of the separator protrusion = (average value of the gap of the inner 5 layers + average value of the gap after the inner 6 - 10 layers and later) / 2.

[0077] In some embodiments, the adhesive includes an adhesive polymer and a plasticizer. Due to the combined action of both the adhesive polymer and the plasticizer, the adhesive has good pressure-sensitive properties, and further, the separator can have good pressure-sensitive properties. Since the adhesive force at an action of ≤1 MPa is ≤0.1 N / m, it is possible to avoid the adhesion between layers during the winding and storage of the separator. And since an obvious adhesive action can occur between the electrode plate and the separator at a pressure action of ≥2 MPa, when manufacturing a battery core using this separator, the electrode plate and the separator can be closely adhered at room temperature conditions and an appropriate pressure. On the one hand, it is possible to avoid the occurrence of misalignment between the electrode plate and the separator, which leads to the discard of the battery core and the influence on the battery core performance and the occurrence of safety risks. On the other hand, it is possible to omit the tunnel furnace and the second composite process in the conventional battery core production process, further saving production space and production time, reducing energy consumption, and significantly enhancing the production capacity of battery core production. At the same time, it is possible to enhance the shaping performance, safety performance, and kinetic performance of the battery core, and further enhance the safety performance and kinetic performance of the secondary battery including this battery core and the power consumption device including this secondary battery.

[0078] In some embodiments, the mass ratio of the adhesive polymer to the plasticizer contained in the adhesive is (4 - 19):1, and may be, for example, (4 - 18):1, (4 - 15):1, (4 - 12):1, (4 - 11):1, (4 - 10):1, (4 - 8):1, (4 - 6):1. By the relative content of the plasticizer contained in the adhesive being within the above range, it can be guaranteed that the electrode plate and the separator can obtain a relatively large adhesive force, and at the same time, it will not cause an increase in the resistance of the separator and a decrease in the cycle performance of the secondary battery.

[0079] Here, for the plasticizer content, the instrument model STA449F3 thermogravimetric analyzer of Shimadzu Corporation, Japan, may be adopted. As a specific example, the test method is as follows. Take about 10 mg of the adhesive, set the original mass as M0, heat up to 200 °C, and set the mass as M1. Then, the plasticizer content is M0 - M1, and the adhesive polymer content is M0 - (M0 - M1). Set the test conditions as a temperature range of -100 - 400 °C, a nitrogen gas atmosphere, and 10 °C / min.

[0080] In some embodiments, the adhesive may have a core-shell structure. Both the core and the shell of this core-shell structure may contain an adhesive polymer and a plasticizer. Here, the mass ratio of the adhesive polymer to the plasticizer in the core structure may be (2 - 5):1, for example (3 - 4):1, and the mass ratio of the adhesive polymer to the plasticizer in the shell structure may be (6 - 10):1, for example (7 - 9):1, (7 - 8):1. Both the core and the shell of the core-shell structure are composed of an adhesive polymer and a plasticizer, which can further improve the pressure-sensitive performance of the pressure adhesive, thereby further enhancing the dynamic performance of the separator. On the other hand, the adhesive contains a plasticizer. Under a certain pressure action (for example, 1 MPa - 2 MPa), the plasticizer can quickly migrate between the adhesive polymer and the main material of the separator, plasticize the adhesive polymer, stretch its molecular chain, and generate intermolecular hydrogen bonding with adhesives such as SBR-based adhesives and thickeners such as CMC in the negative electrode plate, and adhesives such as PVDF in the positive electrode plate, enhancing the wetting of the interface and reinforcing the rivet action between the two interfaces. When the action is ≥2 MPa, the core structure is crushed, and the plasticizer in the core is released, which can further improve the above actions.

[0081] In some embodiments, some of the plasticizers are grafted onto the adhesive polymer. For example, based on the weight of the plasticizer, at least 5 wt% of the plasticizer is grafted onto the adhesive polymer. When some of the plasticizers are grafted onto the adhesive polymer, it can prevent a large amount of the plasticizer from migrating into the electrolyte during the cycle, consuming various functional additives in the electrolyte, increasing the resistance value of the separator, and affecting the kinetic performance of the battery core. Here, when at least 5 wt% of the plasticizer is grafted onto the main chain of the adhesive polymer, the separator and the electrode plate can form an effect of "seemingly disconnected but actually connected", further enhancing the durability of room-temperature adhesion, reducing repulsion, and further ensuring that excessive plasticizer does not migrate into the electrolyte during the cycle and affect the battery core performance.

[0082] Here, the grafting rate of the plasticizer in the adhesive polymer may be detected by an infrared test method. Specifically, the adhesive polymer, the plasticizer, and the adhesive are each tested to obtain their Fourier infrared spectrograms. At the position of 1500 cm -1- 1700 cm -1 a peak different from that of the adhesive polymer alone and the plasticizer appears. This peak represents the grafted plasticizer, and the area under the peak represents the amount of the grafted plasticizer, whereby the grafting rate of the plasticizer can be calculated.

[0083] In some embodiments, the average particle size of the adhesive polymer may be 0.5 μm - 3.0 μm, for example, 0.8 μm - 2.8 μm, 1 μm - 2.5 μm, 1.2 μm - 2.3 μm, 1.5 μm - 2 μm, 1.8 μm - 2 μm. The adhesive polymer that meets the average particle size of this application helps it to be uniformly distributed in the composite particles and helps to exert the adhesion between it and the electrode plate under a certain pressure. In some embodiments, the average particle size of the adhesive polymer may be 0.8 μm - 2 μm.

[0084] Here, the average particle size of the adhesive polymer can be measured using a laser particle size analyzer (e.g., Malvern Master Size 3000) with reference to Standard GB / T 19077.1-2016.

[0085] In some embodiments, the DSC melting point of the adhesive may be -50°C - 100°C, such as -45°C - 95°C, -40°C - 90°C, -35°C - 85°C, -30°C - 80°C, -25°C - 75°C, -20°C - 70°C, -15°C - 65°C, -10°C - 60°C, -5°C - 55°C, 0°C - 50°C, 5°C - 45°C, 10°C - 40°C, 15°C - 35°C, 20°C - 30°C, 25°C - 30°C. Thereby, the adhesive satisfying the above DSC melting point can guarantee the adhesive force at room temperature, avoid causing the winding adhesion of the separator due to the excessive adhesive force at 1 MPa, and avoid the weak adhesion between the separator and the electrode plate due to the too small adhesive force at 2 MPa at room temperature, which is disadvantageous for the shaping of the battery core.

[0086] According to some examples, the DSC melting point has the meaning known in the art and may be measured by instruments and methods known in the art. For example, a DSC melting point tester with the instrument model number DSC 200F3 of NETZSC in Germany may be adopted. As a specific example, the test method is as follows. Take about 10 mg of the sample for testing. Set the test conditions as the temperature range: -100 - 200°C, nitrogen gas atmosphere, 10°C / min. When the first heating is selected, the temperature corresponding to the absorption peak is the corresponding DSC melting point.

[0087] In some embodiments, the adhesive polymer includes a copolymer formed by at least one of the following first monomers, at least one of the second monomers, at least one of the third monomers, and at least one reactive monomer of the reactive dispersant, that is, First monomer: Its melting point is generally higher than 80 °C, including acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylolacrylamide, acrylamide, styrene, acrylonitrile, Second monomer: Its melting point is generally 80 °C or lower, including C4-C22 alkyl esters of acrylic acid, isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl (isooctyl) acrylate, cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, ethylene urea ethyl methacrylate, acrylyl methacrylate, dicyclopentenyl oxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate, Third monomer: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, 3-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethyl (meth)acrylamide, diacetoneacrylamide, ethyl acetoacetate methacrylate, divinylbenzene, epoxy resin with an epoxy value of 0.35-0.50, divinylbenzene, Reactive dispersant: including polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, polyvinyl alcohol. Optionally, the degree of alcoholysis of these reactive dispersants is ≧85%, the average degree of polymerization is 400-2000, preferably the degree of alcoholysis is ≧88%, and the average degree of polymerization is 500-1600.

[0088] Thus, the adhesive polymer configured as such has appropriate swelling, pressure sensitivity and adhesion performance, and has an appropriate elastic modulus, whereby the battery core has excellent shaping effect, kinetic performance and safety performance.

[0089] It should be noted that in this application, the term "alcohol decomposition degree" refers to the percentage of hydroxyl groups in the product obtained after alcohol decomposition in the original group, and the unit is mole fraction %. For example, if there are 100 original groups (ester groups) and 60 hydroxyl groups after alcohol decomposition, the alcohol decomposition degree is 60%.

[0090] It should be noted that in this application, the term "average degree of polymerization" means that the polymer is composed of homologous polymer molecules with different degrees of polymerization, and its degree of polymerization has a statistically average meaning. There are two most commonly used methods to represent the average degree of polymerization. The degree of polymerization obtained by averaging by the number of molecules is called the number average degree of polymerization, and the degree of polymerization obtained by averaging by weight is called the weight average degree of polymerization. In this application, the "average degree of polymerization" is the number average degree of polymerization.

[0091] In some embodiments, the plasticizer may include at least one of glycerol C4-C10 alkyl diether or monoether, glycerol C4-C10 carboxylic acid monoester or diester, propylene glycol C4-C10 alkyl monoether and glycerol.

[0092] In some embodiments, the adhesive may be synthesized by the following synthesis method and includes the following steps.

[0093] Step 1: To a solvent (e.g., deionized water), add, in sequence, an emulsifier (e.g., allylsulfonate) at 0.1 wt% - 1 wt% (based on the total weight of the reaction monomer mixture (including a first monomer, a second monomer, a third monomer, and a reactive dispersant), an auxiliary agent (including an emulsifier, a stabilizer, and an aqueous initiator), and a plasticizer, the same hereinafter), an oligomer (e.g., octadecyl methacrylate) at 2 wt% - 3 wt% with a number average molecular weight ≤ 1000 and a melting point of 0°C - 30°C. Control the rotation speed of the homogenizer at 8000 r / min - 12000 r / min, e.g., 10000 r / min, for dispersion. The dispersion time may be 20 min - 60 min, e.g., 50 min, and the dispersion reaction temperature is 20°C - 40°C, e.g., 25°C, to obtain a first mixture.

[0094] Step 2: Add 1 wt% - 4 wt% of a stabilizer to the first mixture, for example, at least one of polyethylene oxide, allyl polyether sulfate, methylene succinic acid (itaconic acid), styrene sulfonic acid, sodium vinyl sulfonate, and sodium nanocellulose. Control the rotation speed of the homogenizer at 6000 r / min - 8000 r / min, e.g., 6500 r / min, for mixing. The time is 20 min - 60 min, e.g., 30 min, and the mixing reaction temperature is 20°C - 60°C, e.g., 45°C, to obtain a second mixture.

[0095] Step 3: Add 0.05 wt% - 0.5 wt% of an aqueous initiator to the second mixture, for example, sodium bicarbonate, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, t-butyl peroxybenzoate, t-butyl peroxypivalate, methyl ethyl ketone peroxide, cyclohexanone peroxide, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, potassium persulfate, sodium persulfate, ammonium persulfate, at least one of azobisisobutyronitrile and azobisisoheptonitrile. Control the rotation speed of the homogenizer to 8000 r / min - 12000 r / min, for example 8000 r / min for mixing, and the time is 20 min - 60 min, for example 30 min. The reaction temperature is 60°C - 80°C, for example 72°C, to obtain a third mixture.

[0096] Step 4: Under the condition that the rotation speed of the homogenizer is 100 r / min - 1000 r / min, for example 400 r / min, gradually and uniformly drop 35 wt% - 45 wt% of the reaction monomer mixture into the third mixture (controlled to be just completed in 60 min), the reaction time is 80 min - 100 min, for example 80 min, to obtain a fourth mixture.

[0097] Step 5: Continue to react the fourth mixture under the conditions that the reaction temperature is 80°C - 90°C, for example 84°C, and the rotation speed of the homogenizer is 12000 r / min - 18000 r / min, for example 15000 r / min, and the time is 120 min - 240 min, for example 180 min, to obtain a fifth mixture.

[0098] Step 6: Add 10 wt% - 20 wt% of a plasticizer, for example glycerol, to the fifth mixture, control the reaction temperature to 80°C - 90°C, for example 84°C, control the rotation speed of the homogenizer to 12000 r / min - 18000 r / min, for example 15000 r / min, and the reaction time is 120 min - 240 min, for example 180 min, to obtain a sixth mixture.

[0099] Step 7: Add 0.05 wt% - 0.5 wt% of an aqueous initiator, such as ammonium persulfate - sodium bicarbonate, to the sixth mixture. Control the rotation speed of the homogenizer at 8000 r / min - 12000 r / min, such as 8000 r / min, and the time is 20 - 60 min, such as 30 min. The reaction temperature is 60°C - 80°C, such as 72°C, to obtain a seventh mixture.

[0100] Step 8: Gradually and uniformly drop 30 wt% - 40 wt% of a reaction monomer mixture into the seventh mixture under the condition that the rotation speed of the homogenizer is 100 r / min - 1000 r / min, such as 400 r / min (control so that the dropping is just completed in 60 min). The reaction time is 100 min - 160 min, such as 120 min, to obtain an eighth mixture.

[0101] Step 9: Add 5 wt% - 20 wt% of a plasticizer, such as glycerol, to the eighth mixture. Control the reaction temperature at 80°C - 90°C, such as 84°C, the rotation speed of the homogenizer at 12000 r / min - 18000 r / min, such as 15000 r / min, and the time at 120 min - 240 min, such as 180 min, to obtain a ninth mixture.

[0102] Step 10: Cool the temperature of the ninth mixture to 50°C or below, filter and discharge it to obtain an adhesive with a core - shell structure. Those skilled in the art can also synthesize and obtain an adhesive with a non - core - shell structure by referring to the above method (omitting steps 7 - 9 and changing the mass fractions of the plasticizer and the reaction monomer mixture added accordingly).

[0103] In some embodiments, in the separator of the present application, the mass ratio of the solid content in the composite particles to the adhesive is (80-90):(5-20), for example (80-90):(6-20), (80-90):(7-18), (80-90):(8-15), (80-90):(9-11), (80-90):10, (81-89):(5-20), (82-88):(5-20), (83-87):(5-20), (84-86):(5-20), 85:(5-20). The inventor has discovered that by mixing the composite particles and the adhesive in the coating at this ratio, on the one hand, the safety performance and energy density of the battery can be improved simultaneously, and on the other hand, the adhesiveness between the separator and the electrode plate can be made appropriate, thereby improving the kinetic performance of the battery. In some other embodiments, in the separator of the present application, the mass ratio of the composite particles to the adhesive is (85-90):(8-15).

[0104] In some embodiments, referring to FIG. 4, the separator coating of the present application may further include organic particles, that is, the separator coating includes composite particles, an adhesive, and organic particles, where the organic particles include polytetrafluoroethylene particles, polytrifluorochloroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of a fluorine-containing alkenyl monomer unit and an ethylene monomer unit, copolymer particles of a fluorine-containing alkenyl monomer unit and an acrylic acid monomer unit, copolymer particles of a fluorine-containing alkenyl monomer unit and an acrylate monomer unit, and at least one of the modified compound particles of the above homopolymers or copolymers. The organic particles and the composite particles form the protrusions on the coating surface. Thereby, the cycle performance and safety performance of the battery can be improved.

[0105] In some embodiments, referring to FIG. 4, the organic particles of the separator coating of the present application form a third aggregate. Here, the Dv50 of the third aggregate is 5 μm - 30 μm, for example, 5 μm - 28 μm, 5 μm - 25 μm, 5 μm - 22 μm, 5 μm - 20 μm, 5 μm - 18 μm, 5 μm - 15 μm, 5 μm - 12 μm, 5 μm - 10 μm, 5 μm - 8 μm, 5 μm - 6 μm, etc.

[0106] In some embodiments, referring to FIG. 4, the third aggregate includes organic particles in the form of primary particles, and there is a gap between two adjacent organic particles. This gap may be used as an ion transport channel, thereby improving the ion conductivity of the separator. In some embodiments, the Dv50 of the organic particles in the form of primary particles is 50 nm - 400 nm, for example, 50 nm - 375 nm, 75 nm - 375 nm, 100 nm - 350 nm, 125 nm - 325 nm, 150 nm - 300 nm, 175 nm - 275 nm, 200 nm - 250 nm, 200 nm - 225 nm, etc. In some other embodiments, the Dv50 of the organic particles in the form of primary particles is 100 nm - 200 nm.

[0107] In this application, Dv50 is the particle size corresponding to when the cumulative volume distribution percentage reaches 50%, and Dv10 is the particle size corresponding to when the cumulative volume distribution percentage reaches 10%. In this application, both the Dv10 and Dv50 of the composite particles may be measured by adopting the laser diffraction particle size analysis method. For example, referring to the standard GB / T 19077-2016, measurement is carried out using a laser particle size analyzer (such as Malvern Master Size 3000). The Dv50 of the inorganic particles in the primary particle form, the Dv50 of the polyacrylate particles in the primary particle form, and the Dv50 of the polyacrylate particles in the secondary particle form may be statistically analyzed from the separator SEM diagram. For example, a separator SEM diagram with a magnification of 10Kx is taken. Each sample uses 5 parallel samples. Each parallel sample uses 10 positions. 20 points are selected at each position for statistical analysis, and finally the average value is taken, which is the corresponding particle size. The Dv50 of the first aggregate, the Dv50 of the second aggregate, and the Dv50 of the third aggregate may be statistically analyzed using the CP diagram of the separator. For example, a separator CP diagram with a magnification of 5Kx is taken. Each sample uses 5 parallel samples. Each parallel sample uses 10 positions. 20 points are selected at each position for statistical analysis, and finally the average value is taken, which is the corresponding particle size.

[0108] In some embodiments, the mass ratio of the composite particles to the organic particles is (20~90):(0~70). For example, the mass ratio of the composite particles to the organic particles is (20~90):(5~65), (20~90):(10~60), (20~90):(20~50), (20~90):(30~40), (30~80):(0~70), (40~70):(0~70), (50~60):(0~70), (30~80):(5~65), (40~65):(10~55), (45~60):(20~45), (55~60):(30~45). Thereby, the wettability and distribution uniformity of the electrolyte can be improved, the high-temperature storage performance of the battery can be improved, and the safety performance and cycle performance of the battery can be enhanced. In some other embodiments, the mass ratio of the composite particles to the organic particles is (45~90):(0~45). Thereby, the safety performance and cycle performance of the battery can be enhanced.

[0109] In some embodiments, the coating may further contain other organic compounds, for example, polymers for improving heat resistance, dispersants, wetting agents, and other types of adhesives. The above other organic compounds are all non-particulate substances in the coating. This application is not particularly limited to the types of the above other organic compounds, and any known material having good improvement performance can be selected and used.

[0110] In some embodiments, the single-sided coating weight on the separator per unit area is 0.2 g / m 2 -2 g / m 2 , for example, 0.5 g / m 2 -1.8 g / m 2 , 0.7 g / m 2 -1.5 g / m 2 , 1 g / m 2 -1.5 g / m 2 , 1 g / m 2 -1.2 g / m 2 is.

[0111] In this application, the substrate is a membrane material with a porous structure having good chemical stability and mechanical stability. In some embodiments, the substrate may be a single-layer membrane material or a multi-layer composite membrane material. When the substrate is a multi-layer composite membrane material, the materials of each layer may be the same or different.

[0112] In some embodiments, in the separator of the present application, the substrate may be a porous membrane or a porous non-woven web containing one or more of polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyaryl ether ketone, polyether imide, polyamide imide, polybenzimidazole, polyether sulfone, polyphenylene ether, cycloolefin copolymer, polyphenylene sulfide, and polyethylene naphthalene. In some other embodiments, the substrate is a porous membrane or a porous non-woven web containing polyethylene and / or polypropylene. By selecting the above substrate to manufacture the separator, it is advantageous for the substrate to be combined with the coating via an adhesive to form a separator that is moderately dense, porous, and capable of conducting lithium ions.

[0113] In some embodiments, in the separator of the present application, the substrate has a porosity of 10% - 95%, for example, 15% - 90%, 20% - 85%, 25% - 80%, 30% - 75%, 35% - 70%, 40% - 65%, 45% - 60%, 50% - 55%. In some other embodiments, the substrate of the separator of the present application has a porosity of 35% - 45%. Thereby, while improving the ion conduction performance of the separator, the probability of contact between the positive electrode plate and the negative electrode plate can be reduced. In some embodiments, in the separator of the present application, the substrate has a pore diameter of 0.1 μm - 50 μm, for example, 0.5 μm - 50 μm, 1 μm - 45 μm, 5 μm - 40 μm, 10 μm - 35 μm, 15 μm - 30 μm, 20 μm - 25 μm. In some other embodiments, in the separator of the present application, the substrate has a pore diameter of 0.1 μm - 5 μm. By selecting the substrate having the above pore structure, the separator has good ion conduction performance, reduces the probability of direct contact between the positive electrode plate and the negative electrode plate, and further enhances the dynamics and safety performance of the battery core.

[0114] In some embodiments, the thickness of the substrate is ≤ 10 μm. For example, the thickness of the substrate may be 5 μm - 10 μm, 5 μm - 9 μm, or 7 μm - 10 μm. When controlling the thickness of the substrate within a predetermined range, on the premise of ensuring the cycle performance and safety performance of the battery, the battery energy density can be further improved.

[0115] According to some embodiments, the types of substances of the polyacrylate particles, organic particles, and adhesive may be tested by adopting devices and methods known in the art. For example, the infrared spectrum of the material may be tested to determine the characteristic peaks contained therein, thereby determining the type of the material. Specifically, infrared spectrum analysis may be performed on the organic particles using instruments and methods known in the art, such as an infrared spectrometer. For example, the IS10 type Fourier transform infrared spectrometer of Nicolet, USA may be adopted and tested in accordance with the general rules of the infrared spectrum analysis method of GB / T6040 - 2002.

[0116] The second aspect of the present application further provides a method for manufacturing a separator, and this method includes step (1) of providing a substrate, and step (2) of forming a coating containing composite particles and an adhesive on at least a part of the surface of the substrate. The composite particles form protrusions on the coating surface. The composite particles include polyacrylate particles and inorganic particles, and the inorganic particles are present between at least two of the polyacrylate particles. The crosslinking degree a of the composite particles and its mass swelling degree b in the electrolyte satisfy a / b ≥ 1 and a ≥ 75%.

[0117] Specifically, the substrate, composite particles, and adhesive are the same as those described above, and will not be further described herein.

[0118] In some embodiments, the separator includes a substrate and a coating, and the coating is installed only on one surface of the substrate.

[0119] In some embodiments, the separator includes a substrate and a coating, and the coating is simultaneously disposed on two surfaces of the substrate.

[0120] In some embodiments, step (2) may be performed by adopting step (2-1) of providing a coating slurry including composite particles and an adhesive, and step (2-2) of applying the coating slurry to at least one side of the substrate and drying to obtain the separator.

[0121] In some embodiments, in step (2-1), the solvent in the coating slurry may be water, such as deionized water.

[0122] In some embodiments, in step (2-1), the coating slurry may further include other organic compounds, for example, a polymer for improving heat resistance, a dispersant, a wetting agent, and an emulsion adhesive. Here, the other organic compounds are all non-particulate in the dried coating.

[0123] In some embodiments, in step (2-1), the coating slurry may further include organic particles, and the organic particles and the composite particles jointly form the protrusions on the coating surface. The organic particles include at least one of polytetrafluoroethylene particles, polytrifluorochloroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of a fluorine-containing alkenyl monomer unit and an ethylene monomer unit, copolymer particles of a fluorine-containing alkenyl monomer unit and an acrylic acid monomer unit, copolymer particles of a fluorine-containing alkenyl monomer unit and an acrylate monomer unit, and modified compound particles of each of the above homopolymers or copolymers.

[0124] In some embodiments, in step (2-2), the coating is performed by using a coater.

[0125] In the embodiments of the present application, there is no special restriction on the model number of the coater, and a commercially available coater may be used.

[0126] In some embodiments, in step (2-2), the coating may adopt processes such as transfer coating, rotary spray coating, dip coating, etc. For example, the coating may adopt transfer coating.

[0127] In some embodiments, the coater includes a gravure roll, and the gravure roll is used to transfer the coating slurry to the substrate.

[0128] By controlling the above process parameters within a predetermined range, the use performance of the separator of the present application can be further improved. Those skilled in the art can selectively adjust one or several of the above process parameters according to the actual production situation.

[0129] The above substrate, composite particles, adhesive and organic particles can all be obtained commercially.

[0130] The third aspect of the present application provides a battery, which includes the separator of the first aspect or the separator manufactured by adopting the second aspect.

[0131] A battery is a battery that can continue to be used by activating the active material in a manner of charging after discharging.

[0132] Generally, a battery includes a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. During the charge and discharge of the battery, active ions reciprocate between the positive electrode plate and the negative electrode plate for occlusion and release. The separator is installed between the positive electrode plate and the negative electrode plate and plays a role of isolation. The electrolyte plays a role of conducting ions between the positive electrode plate and the negative electrode plate.

[0133] [Positive electrode plate] In a battery, the positive electrode plate generally includes a positive electrode current collector and a positive electrode film layer disposed on the positive electrode current collector, and the positive electrode film layer contains a positive electrode active material.

[0134] The positive electrode current collector may adopt a conventional metal foil sheet or a composite current collector (a composite current collector may be formed by disposing a metal material on a polymer substrate). As an example, the positive electrode current collector may adopt an aluminum foil.

[0135] The specific type of the positive electrode active material is not limited, and an active material known in the art and usable for a battery positive electrode may be adopted, and those skilled in the art can select according to actual needs.

[0136] As an example, the positive electrode active material may include, but is not limited to, one or more of lithium transition metal oxides, lithium-containing phosphates having an olivine structure, and modified compounds thereof. Examples of lithium transition metal oxides may include, but are not limited to, one or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and modified compounds thereof. Examples of lithium-containing phosphates having an olivine structure may include, but are not limited to, one or more of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite material of lithium manganese iron phosphate and carbon, and modified compounds thereof. These materials can all be obtained by commercial methods.

[0137] The modified compound of each of the above materials may be one that performs doping modification and / or surface coating modification on the material.

[0138] The positive electrode film layer generally further includes a selective adhesive, a conductive agent, and other selective auxiliaries.

[0139] As an example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, Super P (SP), graphene, and carbon nanofibers.

[0140] As an example, the adhesive may include one or more of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyacrylic acid (PAA), carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[0141] [Negative electrode plate] In the battery, the negative electrode plate generally includes a negative electrode current collector and a negative electrode film layer disposed on the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.

[0142] The negative electrode current collector may employ a conventional metal foil sheet or a composite current collector (for example, a composite current collector may be formed by disposing a metal material on a polymer substrate). As an example, the negative electrode current collector may employ a copper foil.

[0143] The specific type of the negative electrode active material is not limited, and an active material that can be used for a battery negative electrode known in the art may be adopted, and those skilled in the art can select according to actual needs. By way of example, the negative electrode active material may include, but is not limited to, one or more of artificial graphite, natural graphite, hard carbon, soft carbon, silicon-based materials, and tin-based materials. The silicon-based materials may include one or more of silicon alone, silicon oxide (such as silicon monoxide), silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based materials may include one or more of tin alone, tin acid compounds, and tin alloys. All of these materials can be obtained by commercial methods.

[0144] In some embodiments, in order to further improve the energy density of the battery, the negative electrode active material may include a silicon-based material.

[0145] Generally, the negative electrode film layer further selectively includes an adhesive, a conductive agent, and other optional auxiliaries.

[0146] By way of example, the conductive agent may include one or more of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0147] By way of example, the adhesive may include one or more of styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene-vinyl acetate copolymer (EVA), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[0148] By way of example, the other optional auxiliaries may include a thickener and a dispersant (such as sodium carboxymethyl cellulose CMC-Na), and a PTC thermistor material.

[0149] [Electrolyte solution] The battery may contain an electrolyte solution, which functions to conduct ions between the positive electrode and the negative electrode. The electrolyte solution may contain an electrolyte salt and a solvent.

[0150] As an example, the electrolyte salt may include one or more of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(oxalato)borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalato)phosphate (LiDFOP), and lithium tetrafluoro(oxalato)phosphate (LiTFOP).

[0151] As an example, the solvent may include one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), ethyl methyl sulfone (EMS), and diethyl sulfone (ESE).

[0152] In some embodiments, the electrolytic solution further contains an additive. For example, the additive may include a negative electrode film-forming additive, a positive electrode film-forming additive, and further, an additive that can improve some performances of the battery, such as an additive that improves the overcharge performance of the battery, an additive that improves the high-temperature performance of the battery, and an additive that improves the low-temperature performance of the battery.

[0153] In some embodiments, the battery may be a lithium-ion secondary battery.

[0154] The embodiments of the present application are not particularly limited to the shape of the battery, which may be cylindrical, square, or any other arbitrary shape. FIG. 5 shows a battery 1 having a square structure as an example.

[0155] In some embodiments, the battery may include an exterior body. This exterior body is used to package the positive electrode plate, the negative electrode plate, and the electrolyte.

[0156] In some embodiments, the exterior body may include a case and a cover plate. Here, the case may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodation cavity. The case has an opening communicating with the accommodation cavity, and the cover plate can be covered on the opening so as to seal the accommodation cavity.

[0157] The positive electrode plate, the negative electrode plate, and the separator can form an electrode assembly by a winding process or a lamination process. The electrode assembly is packaged in the accommodation cavity. The electrolyte may adopt an electrolytic solution, and the electrolytic solution is infiltrated into the electrode assembly. The number of electrode assemblies included in the battery may be one or more, and can be adjusted according to demand.

[0158] In some embodiments, the exterior body of the battery may be a hard case, such as a hard plastic case, an aluminum case, or a steel case.

[0159] The outer casing of the battery may be a pouch, for example, a bag-shaped pouch. The material of the pouch may be plastic, and may include one or more of, for example, polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0160] In some embodiments, the battery can be assembled into a battery module, and the number of batteries included in the battery module may be plural, and the specific number can be adjusted according to the application and capacity of the battery module.

[0161] FIG. 6 shows a battery module 2 as an example. Referring to FIG. 6, in the battery module 2, a plurality of batteries 1 may be arranged in order along the longitudinal direction of the battery module 2. Of course, they may be arranged in any other manner. Furthermore, these plurality of batteries 1 can be fixed by fasteners.

[0162] The battery module 2 may further include a housing having an accommodation space, and the plurality of secondary batteries 1 are accommodated in this accommodation space. In some embodiments, the battery module may be further assembled into a battery pack, and the number of battery modules included in the battery pack can be adjusted according to the application and capacity of the battery pack.

[0163] FIGS. 7 and 8 show a battery pack 3 as an example. Referring to FIGS. 7 and 8, the battery pack 3 may include a battery box and a plurality of battery modules 2 installed in the battery box. The battery box includes an upper housing 4 and a lower housing 5, and the upper housing 4 is covered on the lower housing 5 to form a sealed space for accommodating the battery module 2. The plurality of battery modules 2 may be arranged in the battery box in any manner.

[0164] [Power consumption device] The present application further provides a power consumption device, which includes the battery for providing electrical energy. Specifically, the battery may be used as the power source of the power consumption device and may also be used as the energy storage unit of the power consumption device. The power consumption device may be a mobile device (such as a mobile phone, a laptop computer), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck), an electric train, a ship, a satellite, or an energy storage system, but is not limited thereto.

[0165] FIG. 9 shows a power consumption device as an example. This power consumption device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0166] As another example of the power consumption device, it may be a mobile phone, a tablet computer, or a laptop computer. This power consumption device generally requires thinning, and a battery may be adopted as the power source.

[0167] To more clearly illustrate the technical problems, technical solutions, and beneficial effects solved by the embodiments of the present application, the following will further describe in more detail by combining the embodiments with the drawings. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and does not impose any limitation on the present application and its applications. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the protection scope of the present application.

[0168] I. Manufacturing of the separator (1) Provide a PE substrate with a thickness of 9 μm, a hole diameter of 50 nm, and a porosity of 38%.

[0169] (2) Formulation of the coating slurry: Composite particles, an adhesive (the glass transition temperature thereof is about 10 °C, an adhesive polymer with a mass ratio of 5:1 (average particle size is 1.1 μm), a plasticizer (here, 8 wt% of the plasticizer is grafted onto the adhesive polymer based on the weight of the plasticizer), and a small amount of deionized water. Here, the adhesive polymer is 30% isobutyl acrylate + 25% isooctyl acrylate + 5% 2-hydroxypropyl methacrylate + 15% styrene + 22% acrylonitrile + 3% polyvinyl alcohol copolymer, and the plasticizer is glycerol) (the solid mass ratio of the composite particles to the adhesive is 90:10) and organic particles are uniformly mixed in an appropriate amount of solvent deionized water to obtain a coating slurry with a solid content of 12% (by weight).

[0170] (3) After applying the coating slurry formulated in step (2) to two surfaces of the PE substrate with a coater, it is dried. Here, the drying temperature is 50 °C and the drying time is 25 s.

[0171] Here, the above composite particles are manufactured by adopting the following steps.

[0172] a. At room temperature, the required monomers are uniformly stirred and mixed at a weight percentage ratio of 29 wt% 2-hydroxyethyl acrylate, 35 wt% n-butyl acrylate, 5 wt% methyl methacrylate, 1 wt% trimethylolpropane triacrylate, 20 wt% acrylonitrile, and 10 wt% acrylamide to obtain a mixed monomer. b. 2 kg of the mixed monomer, 60 g of sodium lauryl sulfate emulsifier, 20 g of ammonium persulfate initiator, and 2.40 kg of deionized water are added to a 10 L four-necked flask equipped with a mechanical stirring device, a thermometer, and a condenser tube. It is stirred and emulsified at a rotation speed of 1600 rpm for 30 min, and then heated to 75 °C under nitrogen gas protection and reacted for 4 h. After that, it is adjusted to pH = 6.5 using a 1 wt% NaOH aqueous solution, immediately cooled to 40 °C or below and discharged to obtain an emulsion-like organic polymer with a solid content of about 45 wt%. c. The above-mentioned organic polymer dry weight and aluminum oxide were added to an appropriate amount of deionized water at a mass ratio of 9:1, stirred for 1 h to be thoroughly mixed, then the solvent was removed through spray drying to obtain a powder. And through polishing and grinding, composite particles with a Dv50 of 5 μm were obtained. All the materials used in the examples may be obtained commercially. For example, The organic particles may be purchased from Ruyuan Dongyangguang Fluororesin Co., Ltd., The adhesive may be purchased from Sichuan Yindi Le Technology Co., Ltd., The substrate may be purchased from Shanghai Enjie New Materials Co., Ltd.

[0173] The corresponding parameters in the manufacturing process of separator 1-50 are shown in Table 1-5.

[0174]

Table 1

[0175]

Table 2

[0176]

Table 3

[0177]

Table 4

[0178]

Table 5

[0179] II. Battery Manufacturing Example 1 1. Manufacturing of the positive electrode plate LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), conductive agent carbon black (Super P), and polyvinylidene fluoride (PVDF) as an adhesive were uniformly mixed in an appropriate amount of solvent N-methylpyrrolidone (NMP) at a mass ratio of 96.2:2.7:1.1 to obtain a positive electrode slurry. The positive electrode slurry was applied to a positive electrode current collector aluminum foil, followed by drying, cold pressing, stripping, and cutting processes to obtain a positive electrode plate. The positive electrode surface density was 0.207 mg / mm 2 and the compaction density was 3.5 g / cm 3 .

[0180] 2. Manufacturing of the negative electrode plate Artificial graphite as the negative electrode active material, carbon black (Super P) as the conductive agent, and styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC-Na) as adhesives were uniformly mixed in an appropriate amount of solvent deionized water at a mass ratio of 96.4:0.7:1.8:1.1 to obtain a negative electrode slurry. The negative electrode slurry was applied to a negative electrode current collector copper foil, followed by drying, cold pressing, stripping, and cutting processes to obtain a negative electrode plate. The negative electrode surface density was 0.126 mg / mm 2 and the compaction density was 1.7 g / cm 3 .

[0181] 3. Separator Separator 1 manufactured above was adopted as the separator.

[0182] 4. Manufacturing of the electrolyte Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed at a mass ratio of 3:5:2 to obtain an organic solvent. Thoroughly dried electrolyte salt LiPF6 was dissolved in the above mixed solvent, and the concentration of the electrolyte salt was 1.0 mol / L. After uniformly mixing, an electrolyte was obtained.

[0183] 5. Manufacture of the battery The positive electrode plate, separator, and negative electrode plate were laminated in sequence, with the separator positioned between the positive and negative electrode plates to play a role in isolation, and then wound to obtain an electrode assembly. The electrode assembly was placed in an outer package, and the manufactured electrolyte was injected into the dried secondary battery. After undergoing the processes of vacuum packaging, standing, formation, and shaping, a secondary battery was obtained.

[0184] The secondary batteries of Examples 2 - 42 and Comparative Examples 1 - 8 were similar to the manufacturing method of the battery in Example 1. The difference was that different separators were used. The secondary batteries of Examples 2 - 42 adopted separator 2 - 42, and the secondary batteries of Comparative Examples 1 - 8 adopted separators 43 - 50.

[0185] III. Evaluation of the Adhesion Performance of the Separator The test process is as follows.

[0186] 1. The manufactured separator with a length of 300 mm × width of 100 mm and the positive and negative electrode plates manufactured above were selected.

[0187] 2. The upper and lower parts of the separator were wrapped with paper and cut into samples with a size of 54.2 mm × 72.5 mm using a knife die and a press machine.

[0188] 3. The cut separator samples and the positive electrode plate were neatly laminated. Teflon with a size of 130 mm × 130 mm was laid on the upper and lower parts respectively. The laminated samples were placed in the middle of a cardboard with a size of 200 mm × 200 mm, and another cardboard with a size of 150 mm × 160 mm was covered.

[0189] 4. The laminated samples were placed in a flat press to adjust the pressure and air pressure. The flat press pressure was set to 3500 KG ± 10 KG (the contact area was approximately 50 mm × 100 mm, and the actual pressure after conversion was approximately 7 MPa), T was set to 25 °C, the time was set to 10 s, and then pressed.

[0190] 5. Samples hot-pressed using a knife die and a press were cut into small pieces of 72.5 mm × 15 mm.

[0191] 6. One side of the positive electrode plate was fixed to the steel plate with double-sided tape, and a separator was adhered to the other side. A4 paper with a width of 15 mm was bonded to the separator using double-sided tape, and the production of the test sample was completed.

[0192] 7. The Gotech tensile machine was turned on, and the parameters were set in sequence: adhesion test, speed 50 mm / min, and starting jig pitch 40 mm.

[0193] 8. The test sample was placed between the jigs, the end of the steel plate was fixed to the lower collet, and the A4 paper was fixed to the upper collet. The upper and lower end collets were clamped with jigs respectively.

[0194] 9. Click the operation interface for stretching the computer desktop, clear the force, displacement, etc., and then click "Start" to perform a pre-stretch of about 5 mm. After the pre-stretch, clear the force, displacement, etc. again and start the test. During the test, fix the steel plate fixing the electrode plate, and the tensile machine pulled the A4 paper upward to peel the separator from the positive electrode plate.

[0195] When the test was completed, the complete data was exported and saved.

[0196] 10. Each group measured at least 5 test samples. When the repeatability of the adhesion test curves of the 5 test samples was relatively good, the next group of tests was carried out. Otherwise, it was necessary to re-perform the test until the repeatability of the 5 test samples became relatively good.

[0197] 11. After the test, an adhesion strength (N / m)-displacement curve was created. The average value of the data points from the 100th to the 300th was taken as the adhesion force, and the measured adhesion force was designated as F1.

[0198] 12. Repeat Steps 1 to 11, where in Step 4, change the pressure to 1500 Kg ± 10 KG (the actual pressure after conversion is equivalent to about 3 MPa), change the temperature T to 95 °C, and let the obtained adhesive force be F2.

[0199] IV. Separator Compressive Elastic Modulus Test Method: Sample Pretreatment: 1. Cut out the separator with a knife die, and the stacking order is knife die / white paper / separator / white paper / brick. Cut out 5 layers at a time, make 100 layers as a set, and create 3 sets of parallel samples. The sample size is 60 * 70 mm. 2. Cut out with a guillotine to obtain an aluminum plastic film with a size of 90 * 200 mm. 3. Fold the aluminum plastic film in half along the longitudinal direction, fix the cut separator sample at the center positions of the four sides with green adhesive, and put it into a Pocket bag. 4. Use a top sealer to side-seal and seal the two long sides of the sample, evacuate the air, and package the top. The heating temperature of the sealer is 185 °C. 5. Place a spacer at the center position of the packaged sample, draw a frame and mark it. 6. Use a micrometer to measure the thickness of the separator within the marked position at 4 points on the long side and 3 points on the short side.

[0200] Sample Test: 1. Turn on the in-situ expansion test system IEST SWE2110, turn on the operation software MISS and pressure correction, and select the compression experiment (transient) and thickness correction. 2. Place the sample on the upper and lower fixtures, move the upper fixture, and ensure that the upper fixture is at the position where it marks the frame of the sample. 3. Click the MISS software to start the experiment. After the test is completed, measure the thickness M1 of the sample, and mark the indentation positions of the upper and lower fixtures of the sample on both sides with a marker. 4. Repeat Steps 2 - 3 and test again.

[0201] Data processing: 1. Stress = Pressure * 10 / Fixture area, Deformation = Initial thickness (M1) - Real-time thickness, Strain = Deformation / Initial thickness, 2. With strain as the abscissa and stress as the ordinate, a stress-strain curve was created. By linearly fitting the stress / strain curve at 3 MPa - 5 MPa, the separator compression elastic modulus was obtained.

[0202] V. Evaluation of the resistance performance of the separator The test process is as follows.

[0203] (1) Preparation of the separator: Each measured separator was cut into samples of the same size (45.3 mm * 33.7 mm), the samples were baked in an environment at 60 °C for at least 4 h, and then quickly transferred to a class 100 cleaning glove box at 25 °C for standby. (2) Manufacture of the symmetric battery confinement Pocket bag (symmetric battery confinement aluminum plastic bag (the aluminum plastic bag is a general-purpose product obtained by laminating polypropylene for pouch cells and aluminum foil)): A blank symmetric battery assembled with Cu Foil against Cu Foil (copper foil against copper foil) as the current collector was used. The confinement of this Pocket bag was realized by punching in the middle of the green adhesive. The Pocket bag needs to be baked in an environment at 60 °C for at least 4 h before use and then quickly transferred to the class 100 cleaning glove box at 25 °C described in (1) above for standby. (3) Assembly of the symmetric battery: Using the anode plate as the electrode, five sets of symmetric battery samples with different separator layer numbers (1, 2, 3, 4, 5 layers) were assembled in their original positions in the glove box described in (1) above. Each set of samples has five parallel samples. The Pocket bag was side-sealed with a simple packaging machine, injected with liquid (300 μL) with a pipette gun, and bottom-sealed. (4) Attachment of the jig to the assembled symmetric battery: Place the assembled symmetric battery in the glove box described in (1) above overnight so that the electrolyte sufficiently infiltrates the separator. The next day, attach the metal jig, control the pressure of the jig to 0.7 MPa, (5) Measurement of electrochemical impedance spectroscopy (EIS): Before measurement, put symmetric batteries with different numbers of separator layers into a high and low temperature chamber and maintain a constant temperature of 25°C for half an hour, and measure the EIS at the set temperature (25°C). (In the case of low temperature (for example, -25°C - 0°C), the constant temperature time can be extended accordingly, for example, by about 2 hours), (6) Employ a French Bio-Logic VMP3 electrochemical working station with a voltage < 5V, current < 400 mA, and current accuracy: 0.1% * 100 μA. During measurement, set the measurement conditions of EIS to a voltage frequency of 1 MHz - 1 kHz, set the disturbance voltage to 5 MV, and control the pressure of the jig to 0.7 MPa, (7) Create a scatter plot of the real part of the EIS data against the negative imaginary part, and compare the EIS diagram obtained by plotting the data of parallel samples with different numbers of layers and the same number of layers on one graph with the EIS raw data, (8) Remove the points outside the first quadrant from the EIS diagram obtained in (7) above to obtain a new EIS diagram. Perform linear fitting on the plots in the first quadrant of the new EIS diagram to obtain a relational expression. When y = 0, an x value is obtained, which is the resistance value of the required electrolyte in the separator. By analogy, if the measured EIS data is subjected to linear fitting processing, the resistance values between parallel samples with different numbers of layers can be obtained.

[0204] VI. Battery performance test 1. Cycle performance of the secondary battery at a biasing force of 0.1 Mpa (1) 25°C cycle performance At 25°C, the secondary batteries obtained in the production of the examples and comparative examples were fixed with three steel jigs. There was a 1-mm single-sided heat-insulating pad between the jig and the battery. A biasing force of 0.1 MPa was applied, and then charging was carried out at a constant current of 1 C rate until the charging cut-off voltage reached 4.2 V. Thereafter, charging was carried out at a constant voltage until the current ≤ 0.05 C. After standing for 5 min, discharging was carried out at a constant current of 0.33 C rate until the discharging cut-off voltage reached 2.8 V. After standing for 5 min, the battery capacity at this time was recorded as C0. The battery was charged and discharged 1500 cycles in this way, and the battery capacity after 1500 cycles was recorded as C1.

[0205] The cycle capacity retention rate of the battery at 25°C = C1 / C0 × 100% (2) 45°C cycle performance At 45°C, the secondary batteries obtained in the production of the examples and comparative examples were fixed with three steel jigs. There was a 1-mm single-sided heat-insulating pad between the jig and the battery. A biasing force of 0.1 MPa was applied, and then charging was carried out at a constant current of 1 C rate until the charging cut-off voltage reached 4.2 V. Thereafter, charging was carried out at a constant voltage until the current ≤ 0.05 C. After standing for 5 min, discharging was carried out at a constant current of 0.33 C rate until the discharging cut-off voltage reached 2.8 V. After standing for 5 min, the battery capacity at this time was recorded as C0. The battery was charged and discharged 1500 cycles in this way, and the battery capacity at this time was recorded as C1.

[0206] The cycle capacity retention rate of the battery at 45°C = C1 / C0 × 100% 2. Cycle performance of the secondary battery with a biasing force of 0.5 Mpa (1) 25°C cycle performance At 25°C, the secondary batteries obtained in the production of the examples and comparative examples were fixed with three steel jigs. There was a 1-mm single-sided heat-insulating pad between the jig and the battery. A biasing force of 0.5 MPa was applied, and then charging was carried out at a constant current of 1 C rate until the charging cut-off voltage reached 4.2 V. Thereafter, charging was carried out at a constant voltage until the current ≤ 0.05 C. After standing for 5 min, discharging was carried out at a constant current of 0.33 C rate until the discharging cut-off voltage reached 2.8 V. After standing for 5 min, the battery capacity at this time was recorded as C0. The battery was charged and discharged 1500 cycles in this way, and the battery capacity after 1500 cycles was recorded as C1.

[0207] Cycle capacity retention rate of the battery at 25°C = C1 / C0 × 100% (2) 45°C cycle performance At 45°C, three secondary batteries obtained from the production of the examples and comparative examples were fixed with three steel jigs. There was a 1-mm single-sided heat insulation pad between the jig and the battery. A biasing force of 0.5 MPa was applied, and then charging was carried out at a constant current of 1C rate until the charging cut-off voltage of 4.2V. Thereafter, charging was carried out at a constant voltage until the current ≤ 0.05C. After standing for 5 min, discharging was carried out at a constant current of 0.33C rate until the discharging cut-off voltage of 2.8V. After standing for 5 min, the battery capacity at this time was recorded as C0. The battery was charged and discharged 1500 cycles in this way, and the battery capacity at this time was recorded as C1.

[0208] The cycle capacity retention rate of the battery at 45°C = C1 / C0 × 100%.

[0209] Table 6 shows the separator and battery performance data of Examples 1-42 and Comparative Examples 1-8 obtained by measurement.

[0210]

Table 6

[0211] As can be seen from Table 6, the adhesion force of the separators in Examples 1-42 to the positive electrode at 25°C and 7 MPa is between 0.2 N / m and 1.5 N / m, and the adhesion force of the separators in Examples 1-42 to the positive electrode at 95°C and 3 MPa is between 0.4 N / m and 5.5 N / m. At the same time, the resistance of the separators in Examples 1-42 is 2.3 Ω or less, the compression elastic modulus is between 50 Mpa and 82 Mpa, and the cycle capacity retention rates of the batteries in Examples 1-42 at an applied force of 0.1 MPa and an applied force of 0.5 MPa are both superior to those of Comparative Examples 1-8. Thereby, it is shown that the adhesion force between the separator and the electrode plate adopted in this application is appropriate, and the resistance is relatively low, thereby improving the kinetic performance and safety performance of the battery.

[0212] Finally, it should be noted that the above-mentioned examples are only for explaining the technical solutions of this application and do not limit it. Although this application has been described in detail with reference to the above-mentioned examples, those skilled in the art can still modify the technical solutions described in the above-mentioned examples, or make equivalent replacements for some or all of their technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of each example of this application, and it should be understood that all of them should be included in the scope of the claims and the specification of this application. In particular, unless there is a structural conflict, the technical features of each item mentioned in each example may be combined in any way. This application is not limited to the specific examples disclosed in this specification, but includes all technical solutions within the scope of the claims.

Explanation of Symbols

[0213] 1 Secondary battery 2 Battery module 3 Battery pack 4 Upper housing 5 Lower housing

Claims

1. A separator comprising: a base material; and a coating formed on at least a part of the surface of the base material, wherein the coating contains composite particles and an adhesive, the composite particles form protrusions on the coating surface, the composite particles contain polyacrylate particles and inorganic particles, and there are inorganic particles between at least two of the polyacrylate particles. The crosslinking degree a of the composite particles and its mass swelling degree b in the electrolyte satisfy a / b≥1 and a≥75%. The electrolyte contains an electrolyte salt and a solvent. The electrolyte salt is lithium hexafluorophosphate (LiPF ６ ) with a concentration of 1.0 mol / L, The separator, wherein the solvent is a mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) in a mass ratio of 3:5:

2.

2. The separator according to Claim 1, wherein the a / b value is 1 - 2.

1.

3. The separator according to Claim 1 or 2, wherein the Dv50 of the composite particles is ≥2.5 μm.

4. The separator according to Claim 1 or 2, wherein the composite particles contain a first aggregate, and the first aggregate contains at least two of the inorganic particles.

5. The separator according to Claim 4, wherein 0.01 μm≤Dv50 of the first aggregate≤Dv10 of the composite particles.

6. The separator according to Claim 1 or 2, wherein the composite particles contain inorganic particles in the form of primary particles.

7. The separator according to Claim 6, wherein the Dv50 of the inorganic particles in the form of primary particles is 0.01 μm - 1 μm.

8. The separator according to Claim 1 or 2, wherein the composite particles contain a second aggregate, and the second aggregate contains at least two of the polyacrylate particles.

9. The separator according to Claim 8, wherein the Dv50 of the second aggregate is 0.3 μm - 5 μm.

10. The separator according to Claim 1 or 2, wherein the polyacrylate particles contain polyacrylate particles in the form of primary particles and / or polyacrylate particles in the form of secondary particles.

11. The separator according to Claim 10, wherein the Dv50 of the polyacrylate particles in the form of primary particles is 50 nm - 400 nm.

12. The separator according to Claim 10, wherein the Dv50 of the polyacrylate particles in the form of secondary particles is 2 μm - 15 μm.

13. The separator according to claim 1 or 2, wherein the content of the inorganic particles in the composite particles is 1 wt% - 50 wt%.

14. The separator according to claim 1 or 2, wherein the height of both sides of the protrusion is 15 μm - 60 μm.

15. The separator according to claim 4, wherein the surface of the protrusion has the first aggregate.

16. The separator according to claim 1 or 2, wherein the glass transition temperature of the polyacrylate particles is 20°C - 80°C.

17. The separator according to claim 1 or 2, wherein the area coverage rate in the coating of the composite particles is 10% - 25%.

18. The separator according to claim 1 or 2, wherein the inorganic particles contain one or more of oxides of silicon, aluminum, calcium, zinc, magnesium, sodium sulfate, sodium benzoate, calcium carbonate and its modification materials.

19. The separator according to claim 1 or 2, wherein the adhesive contains an adhesive polymer and a plasticizer.

20. The adhesive polymer includes a copolymer formed by at least one of the following first monomers, at least one of the second monomers, at least one of the third monomers and at least one of the reactive dispersants, that is, First monomers: including acrylic acid, methacrylic acid, methyl methacrylate, tert-butyl methacrylate, isobornyl methacrylate, methylolacrylamide, acrylamide, styrene, acrylonitrile. Second monomers: including C4-C22 alkyl esters of acrylic acid, isobutyl acrylate, isooctyl acrylate, tert-butyl acrylate, 2-ethylhexyl (isooctyl) acrylate, cyclohexyl acrylate, ethyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, n-hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, ethylene urea ethyl methacrylate, acrylic methacrylate, dicyclopentenyl oxyethyl methacrylate, tetrahydrofuryl methacrylate, trifluoroethyl methacrylate. Third monomer: 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, 3-methacryloxypropyltrimethoxysilane, N-methylolacrylamide, N-butoxymethyl(meth)acrylamide, diacetoneacrylamide, ethyl acetoacetate methacrylate, divinylbenzene, epoxy resin with an epoxy value of 0.35-0.50, including divinylbenzene, Reactive dispersant: polyvinyl alcohol, polypropylene alcohol, polypropylene glycol, polyethylene glycol, including polyvinyl alcohol, the separator according to claim 19.

21. The plasticizer includes at least one of glycerol C4-C10 alkyldiethers, glycerol C4-C10 alkylmonoethers, glycerol C4-C10 carboxylic acid monoesters, glycerol C4-C10 carboxylic acid diesters, propylene glycol C4-C10 alkylmonoethers and glycerol, the separator according to claim 19.

22. The mass ratio of the solid content in the composite particles and the adhesive is (80-90):(5-20), the separator according to claim 1 or 2.

23. The coating further includes organic particles, and the organic particles include at least one of polytetrafluoroethylene particles, polychlorotrifluoroethylene particles, polyvinyl fluoride particles, polyvinylidene fluoride particles, polyethylene particles, polypropylene particles, polyacrylonitrile particles, polyethylene oxide particles, copolymer particles of fluorine-containing alkenyl monomer units and ethylene monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylic acid monomer units, copolymer particles of fluorine-containing alkenyl monomer units and acrylate monomer units, and modified compound particles of the above homopolymers or copolymers. The organic particles and the composite particles form the protrusions on the coating surface, the separator according to claim 1 or 2.

24. The organic particles form a third aggregate, the separator according to claim 23.

25. The separator according to claim 24, wherein the Dv50 of the third aggregate is 5 μm - 30 μm.

26. The separator according to claim 24, wherein the third aggregate contains organic particles in the form of primary particles, and there is a gap between two adjacent organic particles.

27. The separator according to claim 26, wherein the Dv50 of the organic particles in the form of primary particles is 50 nm - 400 nm.

28. The separator according to claim 23, wherein the mass ratio of the composite particles to the organic particles is (20 - 90):(0 - 70).

29. A method for manufacturing the separator according to claim 1, comprising: step (1) of providing a substrate; step (2) of forming a coating containing composite particles and an adhesive on at least a part of the surface of the substrate, wherein the composite particles form protrusions on the coating surface, the composite particles contain polyacrylate particles and inorganic particles, there are inorganic particles between at least two polyacrylate particles, the crosslinking degree a of the composite particles and its mass swelling degree b in the electrolyte satisfy a / b ≥ 1 and a ≥ 75%, and the electrolyte contains an electrolyte salt and a solvent. The electrolyte salt is lithium hexafluorophosphate (LiPF ６ ) with a concentration of 1.0 mol / L, The method for manufacturing a separator, wherein the solvent is a mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) with a mass ratio of 3:5:

2.

30. A battery comprising the separator according to claim 1.

31. A power consumption device comprising the battery according to claim 30, wherein the battery is used to provide electrical energy.

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