Polymer-coated separator having secondary aggregates, method for manufacturing the same, and battery

Abstract

The present invention discloses a polymer-coated separator having secondary aggregates, a method for manufacturing the same, and a battery. The polymer-coated separator comprises a separator substrate and a polymer coating applied to at least one side of the separator substrate, wherein the polymer coating comprises a plurality of randomly distributed spray points, and the spray points comprise a plurality of polymer secondary aggregates formed by the aggregation of primary polymer particles. Any spray point within the polymer coating satisfies the conditions 25 ≤ A / B ≤ 40000 and 100 ≤ C / A ≤ 10⁶, where A represents the projected area of ​​the polymer secondary aggregates on the separator substrate, B represents the projected area of ​​the polymer primary particles on the separator substrate, and C represents the projected area of ​​the spray point on the separator substrate. The present invention provides a coated separator that combines high adhesion, high ion permeability, high liquid absorption and retention, and a low powdering rate by controlling the size of the polymer secondary aggregates and the size distribution of the secondary aggregates within the spray point.

Description

[Technical Field]

[0001] The present invention relates to the technical field of battery separators, and more particularly to polymer-coated separators having secondary aggregates, methods for manufacturing the same, and batteries. [Background technology]

[0002] In recent years, as the number of powered vehicles has increased rapidly, the demand for lithium-ion batteries for power applications has also increased significantly. Data indicates that, with the development of the lithium-ion battery industry, lithium-ion batteries are expected to maintain a high growth rate in the future. As the demand for lithium-ion batteries increases, market demands for lithium-ion battery performance are also increasing, and even higher demands are being placed on lithium-ion battery separators.

[0003] In conventional lithium-ion batteries, the separator and electrode plates are barely bonded, making the lithium-ion battery prone to detachment during charging and discharging, resulting in a reduced battery cycle life. To address this problem, conventional processing methods involve applying an adhesive polymer coating to one or both sides of the separator. This polymer can be PVDF or PMMA. However, while conventional polymer coatings improve the adhesion between the separator and electrode plates, many also alter the pore structure of the separator, resulting in increased internal resistance and slower charging and discharging speeds. Therefore, achieving a separator with a good balance of adhesiveness and permeability in the polymer coating has been extremely difficult. [Overview of the project] [Problems that the invention aims to solve]

[0004] In view of the above, the present invention provides a polymer-coated separator having a secondary aggregate that combines high adhesion, high permeability, and high liquid absorption and retention, a method for producing the same, and a battery. [Means for solving the problem]

[0005] To achieve the above objective, the first aspect of the present invention is: Separator substrate and A polymer coating applied to at least one side of the separator substrate, The polymer coating comprises multiple randomly distributed spray points, and each spray point comprises multiple polymer secondary aggregates formed by the aggregation of primary polymer particles. If any of the spray points within the polymer coating satisfy the conditions 25≦A / B≦40000 and 100≦C / A≦10 6 The following conditions are met, however, A represents the projected area of ​​the polymer secondary aggregates within the spray point on the separator substrate. B represents the projected area of ​​the polymer primary particles within the spray point on the separator substrate. C represents the projected area of ​​the spray point on the separator substrate. JPEG2026514172000002.jpg11170 However, S represents the surface area of ​​the separator substrate, JPEG2026514172000003.jpg10170n provides a polymer-coated separator having secondary aggregates, where the number of spray points within the S area is represented.

[0006] According to any embodiment of the first aspect of the present invention, 25 ≤ A / B ≤ 10000 and 2500 ≤ C / A ≤ 5 × 10 5 , The filename is JPEG2026514172000004.jpg12157.

[0007] According to any embodiment of the first aspect of the present invention, the polymer coating has a thickness of 0.5 μm to 10 μm.

[0008] According to any embodiment of the first aspect of the present invention, the polymer-coated separator has an adhesive strength to a ternary positive electrode ≥ 1 N / m, an adhesive strength to a graphite negative electrode ≥ 0.5 N / m, and / or The ionic conductivity of the polymer-coated separator is 80% to 110% of the ionic conductivity of the separator substrate, and / or The polymer-coated separator has a liquid absorption rate of ≥70%, a liquid retention rate of ≥70%, and / or, The polymer-coated separator has a powdering rate of ≤5%.

[0009] According to any embodiment of the first aspect of the present invention, the polymer coating comprises 80 to 100 parts by mass of a polymer having secondary aggregates, Adhesive 2 to 20 parts by mass, It contains 0.01 to 3 parts by mass of a dispersant.

[0010] According to any embodiment of the first aspect of the present invention, the polymer having the secondary aggregates includes at least one of polyvinylidene fluoride homopolymer (PVDF), polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE), polyvinylidene fluoride-methyl methacrylate copolymer (PVDF-PMMA), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-acrylic acid copolymer, polymethyl methacrylate (PMMA), polyethylene (PE), and acrylate polymer.

[0011] According to any embodiment of the first aspect of the present invention, the adhesive comprises at least one of carboxymethylcellulose, hydroxyethylcellulose, polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, and acrylonitrile multi-component copolymer.

[0012] According to any embodiment of the first aspect of the present invention, the dispersant comprises at least one of ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, acrylic acid-polyurethane, and polyethylene glycol.

[0013] According to any embodiment of the first aspect of the present invention, the separator substrate is at least one selected from a polyethylene film, a polypropylene film, a polyimide film, a polyvinylidene fluoride film, a polyvinylidene fluoride - hexafluoropropylene film, a polyamide film, and a polyethylene terephthalate film.

[0014] According to any embodiment of the first aspect of the present invention, the separator substrate has a thickness of 3 μm to 25 μm and a porosity of 20% to 80%.

[0015] The second aspect of the present invention is Step S01 of uniformly mixing a dispersant and water, and then adding the polymer in a divided manner a times such that the mass added each time of the polymer is 1 / a (a ≥ 2) of the total amount. Each time the polymer is added, first stir at a low speed until all the polymer is added, then stir at a high speed, then stir at a low speed again, optionally perform a grinding treatment, and finally add an adhesive and mix uniformly, and filter to obtain a polymer slurry. Step S02 of coating at least one side surface of the separator substrate with the polymer slurry by a spin - spray method to obtain a polymer coating. As the parameters of the spin - spray, the coating speed is 100 m / min to 300 m / min, the flow rate of the spray slurry is 1500 mL / min to 15000 mL / min, the spray rotation speed is 5000 rpm to 15000 rpm, the number of teeth of the spray rotating disk is 200 to 600, and the distance from the rotating disk to the coating film surface is from 20 cm to 50 cm. Provided is a method for manufacturing a polymer - coated separator having secondary aggregates, including step S03 of drying the separator substrate and the polymer coating to obtain a polymer - coated separator having secondary aggregates.

[0016] According to any embodiment of the second aspect of the present invention, step S01 includes Step S011 of uniformly mixing water and a dispersant to obtain a first mixed solution. Step S012 involves adding the polymer to the first mixed solution in a batch, such that the amount of polymer added in one batch is 1 / a of the total amount, and performing a first stage of dispersion with stirring at a rotation speed of 100 rpm to 600 rpm for 10 to 50 minutes until all the polymer has been added, followed by a second stage of dispersion with stirring at a rotation speed of 1000 rpm to 2000 rpm for 30 to 180 minutes, and finally a third stage of dispersion with stirring at a rotation speed of 100 rpm to 600 rpm for 10 to 50 minutes to obtain the second mixed solution, and Step S013 includes adding adhesive to the second mixed solution, stirring uniformly, and filtering through a 40-300 mesh filter to obtain a polymer slurry.

[0017] According to any embodiment of the second aspect of the present invention, the polymer slurry has a particle size D10 of 1 μm to 4 μm and a D90 of 6 μm to 20 μm.

[0018] According to any embodiment of the second aspect of the present invention, the amount of polymer applied is 0.05 g / m². 2 ~1.5g / m 2 That is the case.

[0019] According to any embodiment of the second aspect of the present invention, the temperature of the drying process in step S03 is 50°C to 90°C.

[0020] A third aspect of the present invention provides a battery comprising a polymer-coated separator having a secondary aggregate according to the first aspect of the present invention or a polymer-coated separator having a secondary aggregate manufactured by the manufacturing method according to the second aspect of the present invention. [Effects of the Invention]

[0021] The beneficial effects are as follows:

[0022] The polymer-coated separator having secondary aggregates according to the present invention provides a coated separator that combines high adhesion, high ion permeability, high liquid absorption and retention, and a low powdering rate by controlling the aggregation state of the polymer secondary aggregates and controlling the distribution of the secondary aggregates within the spray point.

[0023] Additional aspects and advantages of the present invention are, in part, described below, will become apparent from the following description, or will be understood through the practice of the present invention.

[0024] The drawings are used to provide a further understanding of the present invention and constitute part of the specification, and are used to illustrate the present invention together with the following specific embodiments, but are not limiting to the present invention. [Brief explanation of the drawing]

[0025] [Figure 1] This is a 200x scanning electron microscope (SEM) image of the PVDF coating of the polymer-coated separator of the present invention. [Figure 2] This is a 1000x scanning electron microscope (SEM) image of the PVDF coating of the polymer-coated separator of the present invention. [Figure 3] This is a 10,000x scanning electron microscope (SEM) image of the PVDF coating of the polymer-coated separator of the present invention. [Figure 4] This is a schematic diagram of the rotating disk of a high-speed rotating spray device. [Figure 5] This is a flowchart of the process for manufacturing a polymer-coated separator having secondary aggregates. [Modes for carrying out the invention]

[0026] Specific embodiments of the present invention will be described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are for illustrative and interpretive purposes only, and not to limit the present invention.

[0027] A first aspect of the present invention is: Separator substrate and A polymer coating applied to at least one side of the separator substrate, The polymer coating comprises multiple randomly distributed spray points, and each spray point comprises multiple polymer secondary aggregates formed by the aggregation of primary polymer particles. If any of the spray points within the polymer coating satisfy the conditions 25≦A / B≦40000 and 100≦C / A≦10 6 The following conditions are met, however, A represents the projected area of ​​the polymer secondary aggregates within the spray point on the separator substrate. B represents the projected area of ​​the polymer primary particles within the spray point on the separator substrate. C represents the projected area of ​​the spray point on the separator substrate. JPEG2026514172000005.jpg11170 However, S represents the surface area of ​​the separator substrate, JPEG2026514172000006.jpg12170n provides a polymer-coated separator having secondary aggregates, where the number of spray points within the S area is represented.

[0028] The following explains in detail.

[0029] The separator substrate may be an uncoated substrate or a substrate coated with an inorganic particle layer, and is not particularly limited.

[0030] In the embodiments of the present invention, the type of separator substrate is not particularly limited and can be selected according to actual needs. Preferably, the separator substrate may be one or more selected from polyethylene film, polypropylene film, polyimide film, polyvinylidene fluoride film, polyvinylidene fluoride-hexafluoropropylene film, polyamide film, and polyethylene terephthalate film.

[0031] In the embodiments of the present invention, the type of inorganic particles is not particularly limited and can be selected according to actual needs. Preferably, the inorganic particles may be one or more selected from silicon dioxide (SiO2), alumina (Al2O3), magnesium oxide (MgO), zirconia (ZrO2), titanium dioxide (TiO2), calcium oxide (CaO), boehmite (AlOOH), aluminum nitride (AlN), boron nitride (BN), barium sulfate (BaSO4), calcium fluoride (CaF2), and barium fluoride (BaF2).

[0032] The thickness of the separator substrate may be 3 μm to 25 μm, but is preferably 5 μm to 16 μm.

[0033] The porosity of the separator substrate may be 20% to 80%, but is preferably 30% to 50%.

[0034] In this invention, any spray point within the polymer coating has a range of 25 ≤ A / B ≤ 40000 and 100 ≤ C / A ≤ 10 6 The following conditions are met, where A represents the projected area of ​​the polymer secondary aggregates within the spray point on the separator substrate, B represents the projected area of ​​the polymer primary particles within the spray point on the separator substrate, and C represents the projected area of ​​the spray point on the separator substrate. JPEG2026514172000007.jpg12169S represents the sum of the projected areas of all polymer secondary aggregates within the spray points in S on the separator substrate, n represents the number of spray points in S, and S represents the surface area of ​​the separator substrate.

[0035] The shape of the secondary aggregates and spray points is not particularly limited.

[0036] 1. A / B represents the aggregation state of primary particles in the polymer secondary aggregates. If A / B > 40000, the polymer secondary aggregates are too large, resulting in uneven polymer coating thickness, making the coating prone to peeling and powdering, and affecting the local ion permeability of the separator. If A / B < 25, the polymer secondary aggregates are too small, resulting in weaker adhesion strength of the polymer coating and poor liquid absorption and retention of the separator.

[0037] Here, A represents the projected area of ​​the polymer secondary aggregate in the polymer coating. Test method: Select any spray point, take a photograph of the spray point at 200x magnification using a scanning electron microscope, and mark the edge range of the polymer secondary aggregate using software (e.g., image processing software such as ImageJ). The area of ​​this range is the projected area of ​​the polymer secondary aggregate in the polymer coating. Method of marking the edge range of the secondary aggregate: Starting from a point on the edge of the secondary aggregate, draw a line enclosing the edge of the secondary aggregate. The angle of enclosing all line segments must be less than 180° (the interior angle between each line segment and the previous line segment must be less than 180°). If the angle of enclosing a line segment exceeds 180°, cut that line segment and connect it directly to the starting point. The closed region enclosed by the line segments is the range, and its area is the projected area of ​​the secondary aggregate.

[0038] In some examples, the range of A is 0.785 μm 2 ~314μm 2 That is the case.

[0039] B represents the projected area of ​​the primary polymer particles in the polymer coating. Test method: Select any spray point, take a photograph of the spray point at 10,000x magnification using a scanning electron microscope, and mark the area of ​​the primary polymer particles (circular) using software (e.g., image processing software such as ImageJ). The area of ​​this area is the projected area of ​​these primary polymer particles in the polymer coating.

[0040] In some embodiments, the range of B is 7.85×10 -3 μm 2 ~0.785 μm 2 That is.

[0041] The range of A / B is 25 ≤ A / B ≤ 40000, for example, 100~2500, 100~3600, 100~6000, 100~10000, 100~40000 or 200~1600, 200~3600, 200~6000, 200~40000 or 250~6000, 250~8000, 250~10000, 250~40000, etc.

[0042] 2. C / A represents the distribution of polymer secondary aggregates within the spray spot. When C / A < 100, the polymer secondary aggregates within the spray spot are too large and the number is small, so the thickness of the polymer coating becomes non-uniform, the coating is likely to peel off and powder. When C / A > 10 6 In this case, the effective polymer aggregates within the spray spot are too few, so the adhesion of the coating becomes poor, the liquid absorption and retention properties become poor, the exposed area of the separator substrate within the spray spot becomes small, and the ion permeability becomes poor.

[0043] Here, C represents the projected area in the polymer coating of the spray spot. Test method: Select an arbitrary spray spot, take a photo of the spray spot at a magnification of 200 times using a scanning electron microscope, and mark the range of the spray spot using software (such as image processing software like Image J). The area of this range is the projected area in the polymer coating of this spray spot.

[0044] Note that A, B, and C are tested at the same spray spot during the test.

[0045] In some embodiments, the range of C is between 7.85×10 -3 mm 2 ~0.785 mm 2 That is.

[0046] The definition of A is as described above.

[0047] The range of C / A is 100 ≤ C / A ≤ 10 6 For example, ranges such as 100-160000, 600-200000, 600-300000, 800-300000, etc.

[0048] JPEG2026514172000008.jpg17170

[0049] Here, S represents the area of ​​the substrate, and n represents the number of spray points within the area S. The test method involves placing the finished separator under the lens of a static CCD (e.g., a high-resolution electronic measuring microscope GP-300C), taking a photograph at 3x magnification, and using image processing software to calculate the area S of the photograph and the number of spray points n within the photograph.

[0050] The method involves selecting any spray point within the S area (preferably a spray point where D50 is 300 to 600 μm), and the projected area of ​​each secondary aggregate is calculated by testing according to the test method A above and then summing them up.

[0051] For example, JPEG2026514172000010.jpg8117 has percentages of 10-40%, 10-30%, 10-20%, and 10-15%.

[0052] In the embodiments of the present invention, the thickness of the polymer coating is 0.5 μm to 10 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm... 8 μm, 9 μm, 10 μm. The thickness of the polymer coating is controlled within the range of 0.5 μm to 10 μm. If the thickness is too thin, the adhesion will be poor, and if it is too thick, the thickness of the polymer coating will be uneven, the coating will be prone to peeling and powdering, and the ion permeability will be poor.

[0053] In the embodiments of the present invention, the adhesive strength between the polymer-coated separator and the ternary cathode is 1.0 N / m or greater. For example, the adhesive strength between the polymer coating and the ternary cathode plate is 1 N / m... 4 N / m, 4.2 N / m, 4.5 N / m, 4.6 N / m, 4.8 N / m, 5 N / m...

[0054] In the embodiments of the present invention, the adhesive strength between the polymer-coated separator and the graphite negative electrode plate is 0.5 N / m or more. For example, the viscous adhesive strength between the polymer-coated separator and the graphite negative electrode plate is 0.5 N / m, 4 N / m, 4.2 N / m, 4.5 N / m, 4.6 N / m, 4.8 N / m, 5 N / m, and so on.

[0055] The adhesive strength between the polymer-coated separator and the battery electrode can be tested using methods well known in this art. As a specific example, the adhesive strength test method may be as follows: The polymer coating of the battery separator is placed on top of a ternary positive electrode or a graphite negative electrode, and the bond is hot-pressed using a hot press. Then, the 180-degree peel strength is tested at a speed of 50 mm / min using a tensile testing machine to determine the adhesive strength. Here, the hot-pressing conditions are preferably a hot-pressing temperature of 90°C, a hot-pressing pressure of 6.5 MPa, and a hot-pressing time of 60 s.

[0056] In the embodiments of the present invention, the ionic conductivity of the polymer-coated separator is 80% to 110% of the ionic conductivity of the separator substrate, for example, 81%, 82%, 85%, 90%, ... 110%.

[0057] The ionic conductivity of a separator can be tested using well-known methods in this field. As a specific example, the test method for ionic conductivity may be as follows: The ionic conductivity of a separator is given by the formula σ s It can be calculated using =d / (RsS), and σ s R is the conductivity of the separator. s is the separator's resistance, d is the separator's thickness, and S is the separator's effective area.

[0058] In the embodiments of the present invention, the polymer-coated separator has a liquid absorption rate of ≥70%, for example, 70%, 80%, 90%, and 95%, and a liquid retention rate of ≥70%, for example, 70%, 80%, 90%, and 95%.

[0059] The liquid absorption rate and liquid retention rate of a separator can be tested using well-known methods in this art. As a specific example, the test method for liquid absorption rate and liquid retention rate may be as follows: Refer to QB / T 2303.11-2008 "Battery Separators - Part 11: Measurement of Liquid Absorption Rate," cut out a 50 mm x 50 mm separator sample, and let the weighed weight be m0. After weighing, immerse the separator sample in a beaker containing electrolyte for 1 hour, remove the separator sample, suspend it for 3 minutes to remove the electrolyte, and then let the weighed weight be m. After that, let it stand at room temperature for 1 hour, and let the weighed weight be m1. The liquid absorption rate X and liquid retention rate Y of a lithium-ion battery separator can be calculated using the following formulas. JPEG2026514172000011.jpg40156

[0060] In the formula, m0 is the mass of the separator before immersion, m is the mass of the separator after immersion, and m1 is the mass after standing at room temperature for 1 hour.

[0061] In the embodiments of the present invention, the powdering rate of the polymer-coated separator is 5% or less, for example, 4%, 3%, 2%, or 1%.

[0062] The powdering rate primarily represents the degree of powdering in polymer spray coating. Powdering of the separator reduces the adhesion of the separator and increases the risk of hot pressing failure. The specific test method is as follows: Take one roll of the finished polymer spray separator and weigh it, recording this weight as m0. Then, place this separator in a slitter and run it empty. After winding, weigh it again and record this weight as m1. The powdering rate P = (m0 - m1) / m0 × 100%.

[0063] In the embodiments of the present invention, the polymer coating comprises 80 to 100 parts by weight of polymer, 2 to 20 parts by weight of adhesive, and 0.01 to 3 parts by weight of dispersant.

[0064] In the embodiments of the present invention, the polymer having secondary aggregates includes at least one of the following: polyvinylidene fluoride homopolymer (PVDF), polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFE), polyvinylidene fluoride-methyl methacrylate copolymer (PVDF-PMMA), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-acrylic acid copolymer, polymethyl methacrylate (PMMA), polyethylene (PE), and acrylate polymer.

[0065] In this invention, the polymer having secondary aggregates mainly refers to its solid form.

[0066] In some embodiments, the particle size range of the primary polymer particles is 0.1 μm to 1 μm, and the B value is controlled by selecting different types of polymers (e.g., PVDF).

[0067] In the embodiments of the present invention, the type of adhesive is not particularly limited and can be selected according to the actual needs. Preferably, the adhesive may be one or more selected from carboxymethylcellulose, hydroxyethylcellulose, polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, and acrylonitrile multi-component copolymer.

[0068] In the embodiments of the present invention, the type of dispersant is not particularly limited and can be selected according to the actual needs. Preferably, the dispersant may be one or more selected from ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, acrylic acid-polyurethane, and polyethylene glycol.

[0069] The battery separator according to the embodiment of the present invention can be used with various types of batteries, and therefore there are no particular restrictions on the type of battery, and it can be selected according to actual needs. Preferably, it can be used with secondary batteries, especially secondary batteries containing a liquid electrolyte, such as lithium-ion batteries and sodium-ion batteries.

[0070] In a second aspect of the present invention, as shown in Figure 5, Step S01 involves uniformly mixing a dispersant and water, then adding the polymer in a batch of a portions such that the mass of polymer added in one batch is 1 / a of the total amount (a≧2), stirring slowly first, then quickly, then slowly again until all the polymer has been added, optionally grinding the mixture, and finally adding the adhesive and mixing it uniformly, followed by filtration to obtain a polymer slurry. Step S02 involves coating at least one side of a separator substrate with a polymer slurry by a spin-spray method to obtain a polymer coating having spray points, wherein the parameters for the spin-spray are: coating speed of 100 m / min to 300 m / min, spray slurry flow rate of 1500 mL / min to 15000 mL / min, spray rotation speed of 5000 rpm to 15000 rpm, number of teeth on the spray rotating disk of 200 to 600 (a schematic diagram of the rotating disk of a high-speed spin-spray device is shown in Figure 4), and distance from the rotating disk to the surface of the coating film of 20 cm to 50 cm. The present invention provides a method for producing a polymer-coated separator having secondary aggregates, comprising step S03, which involves drying a separator substrate and a polymer coating to obtain a polymer-coated separator having secondary aggregates.

[0071] In the embodiments of the present invention, step S01 of the above manufacturing method is: Step S011: Mix water and dispersant uniformly to obtain a first mixed solution. Step S012 involves adding the polymer to the first mixed solution in a batch, such that the amount of polymer added in one batch is 1 / a of the total amount, and performing a first stage of dispersion with stirring at a rotation speed of 100 rpm to 600 rpm for 10 to 50 minutes until all the polymer has been added, followed by a second stage of dispersion with stirring at a rotation speed of 1000 rpm to 2000 rpm for 30 to 180 minutes, and finally a third stage of dispersion with stirring at a rotation speed of 100 rpm to 600 rpm for 10 to 50 minutes to obtain the second mixed solution, and The process may further include step S013, in which the adhesive is added to the second mixed solution and stirred uniformly, and then filtered through a 40-300 mesh filter (filtration can remove large undispersed PVDF particles) to obtain a polymer slurry.

[0072] PVDF resin can be dispersed more effectively by adding it in multiple stages. First, low-speed stirring prevents scattering of PVDF powder during mixing, and then high-speed stirring accelerates the mixing of PVDF in water. By controlling the number of times PVDF resin is added, the rotation speed and duration of low-speed and high-speed stirring, and the filter size, the desired size of the PVDF slurry (secondary particles) can be obtained, thereby adjusting the A / B range.

[0073] In some examples, the resulting polymer slurry has a D10 particle size of 1 μm to 4 μm and a D90 particle size of 6 μm to 20 μm (controlling the range of the A value). The particle sizes D10 and D90 of the slurry can be measured using a laser particle size distribution analyzer.

[0074] The size of C is adjusted by adjusting the spray rotation speed, slurry flow rate, the number of teeth on the spray disc, and the distance from the rotating disc to the coating surface, thereby adjusting the C / A ratio.

[0075] This is adjusted by controlling the size of JPEG2026514172000012.jpg8117A and the flow rate of the spray slurry.

[0076] In some examples, the resulting spray points are D10 at 100 μm to 300 μm and D90 at 800 μm to 1000 μm.

[0077] The testing method for the D10 and D90 of the spray points may be as follows: Place the finished separator under a static CCD lens, take a photograph at 3x magnification, and use image processing software to calculate the number n of spray points and the size of each spray point in the photograph, thereby statistically determining the D10 and D90 of the spray points.

[0078] In the embodiments of the present invention, conventional drying methods are used for the separator substrate and the PVDF coating.

[0079] In the embodiments of the present invention, the drying temperature is 50°C to 90°C.

[0080] According to the method of the second embodiment of the present invention, a polymer-coated separator having secondary aggregates according to any embodiment of the first embodiment of the present invention can be obtained. The polymer-coated separator having secondary aggregates according to any embodiment of the first embodiment of the present invention is not limited to the manufacturing method according to the second embodiment of the present invention.

[0081] Figures 1 to 3 show scanning electron microscope (SEM) images of the PVDF coating on the coated separator at different magnifications (Model SIGMA 300, acceleration voltage EHT=1kV, working distance WD=5.8~6.1mm, SE2 detector).

[0082] A third aspect of the present invention provides a battery comprising a polymer-coated separator having a secondary aggregate according to the first aspect of the embodiment of the present invention, or a polymer-coated separator having a secondary aggregate produced by the production method according to the second aspect of the embodiment of the present invention.

[0083] In the embodiments of the present invention, the battery is a lithium-ion secondary battery or a sodium-ion secondary battery.

[0084] The present invention will be described below with reference to specific examples. These examples are for illustrative purposes only and do not limit the present invention in any way.

[0085] Unless otherwise specified, all raw materials, reagents, and methods used in the examples are conventional raw materials, reagents, and methods of the art.

[0086] The high-speed rotary spray device is the Hong Kong Yuanbiao DS-800-01 PCS separator spray device.

[0087] Example 1: Preparation of PVDF aqueous spray slurry: 57 kg of water and 0.025 kg of dispersant were weighed and stirred at 500 rpm for 30 minutes to obtain the first mixed solution. 5 kg of PVDF-HFP resin (Toyo-ko HEVER2601, primary particle size 0.1-0.3 μm) was added to the first mixed solution in two batches, with each addition amount being 2.5 kg. After each addition of PVDF-HFP resin, the mixture was first stirred at a low speed of 300 rpm for 30 minutes, then at a high speed of 1000 rpm for 60 minutes, and finally at a low speed of 300 rpm for 20 minutes. The entire mixture was then added to obtain the second mixed solution. Next, 0.25 kg of polyacrylic acid adhesive was added to the second mixed solution and stirred at 50 rpm for 30 minutes to obtain the third mixed solution. Finally, the mixture was filtered through a 200-mesh filter to obtain a PVDF spray slurry with a D10 of 2.1 μm and a D90 of 7.6 μm.

[0088] Coating: The prepared PVDF spray slurry was supplied to the supply tank of a high-speed spin spray device by an automatic supply system, and coated one side of a 9 μm polyethylene wet substrate film with a porosity of 50% by the spin spray method. The coating speed was 150 m / min, the number of teeth on the spray rotating disc was 360, the distance from the rotating disc to the coating surface was 25 cm, the spray slurry flow rate was 5000 mL / min, and the spray rotation speed was 9000 rpm. After drying at 60°C, an aqueous PVDF coated separator was obtained.

[0089] The spray spots obtained after coating were 200 μm for D10 and 800 μm for D90.

[0090] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-1 below.

[0091] Example 2: Preparation of PVDF aqueous spray slurry: 57 kg of water and 0.025 kg of dispersant were weighed and stirred at 500 rpm for 30 minutes to obtain the first mixed solution. 5 kg of PVDF-HFP resin (ArkemaLBG primary particle size 0.15~0.2 μm) was added to the first mixed solution in three portions, with each addition amount being 1.667 kg. After each addition of PVDF-HFP resin, the mixture was first stirred at a low speed of 500 rpm for 30 minutes, then at a high speed of 1500 rpm for 90 minutes, and finally at a low speed of 500 rpm for 30 minutes. The entire mixture was then added to obtain the second mixed solution. Next, 0.25 kg of polyacrylic acid adhesive was added to the second mixed solution and stirred at 50 rpm for 30 minutes to obtain the third mixed solution. Finally, the mixture was filtered through a 300-mesh filter to obtain a PVDF spray slurry with a D10 of 1.6 μm and a D90 of 7.2 μm.

[0092] Coating: The prepared PVDF spray slurry was supplied to a spray supply tank by an automated supply system and coated one side of a 9 μm polyethylene wet substrate with a porosity of 50% by the spin spray method. The coating speed was 200 m / min, the number of teeth on the spray dispersion disc was 450, the distance from the rotating disc to the separator substrate was 25 cm, the spray slurry flow rate was 7500 mL / min, and the spray rotation speed was 9000 rpm. The film was dried at 85°C to obtain an aqueous PVDF coated separator.

[0093] The spray spots obtained after coating were 150 μm for D10 and 850 μm for D90.

[0094] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-1 below.

[0095] Example 3: Preparation of PMMA aqueous spray slurry: 82.75 kg of water and 0.009 kg of dispersant were weighed and stirred at 300 rpm for 30 minutes to obtain the first mixed solution. 15 kg of PMMA powder (particle size of primary particles of 0.2-0.5 μm) was added to the first mixed solution in three portions, with each addition amount being 5 kg. After each addition of PMMA powder, the mixture was first stirred at a low speed of 400 rpm for 30 minutes, then at a high speed of 1200 rpm for 80 minutes, and finally at a low speed of 500 rpm for 30 minutes. When all of the powder was added, the mixture was given to obtain the second mixed solution. Next, 2.25 kg of polyacrylic acid adhesive (with a solid content of 40%) was added to the second mixed solution and stirred at 20 rpm for 30 minutes to obtain the third mixed solution. Finally, the mixture was filtered through a 150-mesh filter to obtain a PMMA aqueous spray slurry with a D10 of 1.7 μm and a D90 of 14.1 μm.

[0096] Coating: The prepared spray slurry was supplied to the spray supply tank by an automated supply system and coated one side of a 9 μm polyethylene wet substrate with a porosity of 50% by the spin-spray method. The coating speed was 150 m / min, the number of teeth on the spray dispersion disc was 360, the distance from the rotating disc to the separator substrate was 25 cm, the spray slurry flow rate was 4000 mL / min, and the spray rotation speed was 9000 rpm. The film was dried at 80°C to obtain an aqueous PMMA coated separator.

[0097] The spray spots obtained after coating were 210 μm for D10 and 800 μm for D90.

[0098] The deposition state A / B of PMMA secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-1 below.

[0099] Example 4: Preparation of PVDF-PMMA copolymer aqueous spray slurry: 45 kg of water and 0.015 kg of dispersant were weighed and stirred at 500 rpm for 30 minutes to obtain the first mixed solution. 5 kg of PVDF-PMMA powder (primary particle size 0.2-0.4 μm) was added to the first mixed solution in two batches, with each addition amount being 2.5 kg. After each addition of PMMA powder, the mixture was first stirred at a low speed of 600 rpm for 30 minutes, then at a high speed of 1800 rpm for 100 minutes, and finally at a low speed of 600 rpm for 30 minutes. The entire mixture was then added to obtain the second mixed solution. Next, 1.25 kg of polyacrylic acid adhesive (with a solid content of 40%) was added to the second mixed solution and stirred at 20 rpm for 30 minutes to obtain the third mixed solution. Finally, the mixture was filtered through a 100-mesh filter to obtain a PVDF-PMMA aqueous spray slurry with a D10 of 2.3 μm and a D90 of 12.5 μm.

[0100] Coating: The prepared spray slurry was supplied to the spray supply tank by an automated supply system and coated onto the ceramic film surface of the 7+2 ceramic coating film by the spin spray method, where 7 is a 7 μm polyethylene wet substrate film with a porosity of 40%, and 2 is a 2 μm ceramic coating. The coating speed was 100 m / min, the number of teeth on the spray dispersion disc was 360, the distance from the rotating disc to the separator substrate was 25 cm, the spray slurry flow rate was 2200 mL / min, and the spray rotation speed was 8500 rpm. The film was dried at 65°C to obtain an aqueous PVDF-PMMA coated separator.

[0101] The spray spots obtained after coating were 230 μm for D10 and 820 μm for D90.

[0102] The deposition state A / B of the PVDF-PMMA secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-1 below.

[0103] Example 5: Preparation of PVDF-PMMA copolymer aqueous spray slurry: The procedure was the same as in Example 4.

[0104] Coating: The prepared spray slurry was supplied to the spray supply tank by an automatic supply system and coated both sides of the 7+2 ceramic coating film by the spin spray method, where 7 is a 7 μm polyethylene wet substrate film with a porosity of 40%, and 2 is a 2 μm ceramic coating. The coating speed was 100 m / min, the number of teeth on the spray dispersion disc was 360, the distance from the rotating disc to the separator substrate was 25 cm, the spray slurry flow rate was 2200 mL / min, and the spray rotation speed was 8500 rpm. The film was dried at 65°C to obtain an aqueous PVDF-PMMA coated separator.

[0105] The spray spots obtained after coating were 230 μm for D10 and 820 μm for D90.

[0106] The deposition state A / B of the PVDF-PMMA secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-1 below.

[0107] Comparative Example 1: Preparation of PVDF aqueous spray slurry: 52 kg of water and 0.3 kg of dispersant were weighed and stirred for 30 minutes to obtain the first mixed solution. 20 kg of PVDF-HFP emulsion with a solid content of 30% (primary particle size 0.15-0.2 μm) was added to the first mixed solution and stirred at 200 rpm for 30 minutes to obtain the second mixed solution. 0.5 kg of polyacrylic acid adhesive was added to the second mixed solution and stirred for 30 minutes to obtain the PVDF spray slurry. The PVDF spray slurry had a D10 of 0.15 μm and a D90 of 0.6 μm.

[0108] Coating: The prepared PVDF spray slurry was supplied to a spray supply tank by an automated supply system and coated one side of a 12 μm polyethylene wet substrate film with a porosity of 50% by the spin spray method. The coating speed was 100 m / min, the number of teeth on the spray dispersion disc was 450, the distance from the rotating disc to the separator substrate was 30 cm, the spray slurry flow rate was 3200 mL / min, and the spray rotation speed was 7200 rpm. The film was dried at 85°C to obtain an aqueous PVDF coated separator.

[0109] The spray spots obtained after coating were 100 μm for D10 and 600 μm for D90.

[0110] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-2 below.

[0111] Comparative Example 2: Preparation of PVDF aqueous spray slurry: 57 kg of water and 0.0025 kg of dispersant were weighed and stirred for 30 minutes to obtain the first mixed solution. 5 kg of PVDF resin powder (primary particle size 0.15-0.2 μm) was added to the first mixed solution, and the mixture was first stirred at a low speed of 200 rpm for 50 minutes, then stirred at 600 rpm for 60 minutes, and finally stirred at 200 rpm for 30 minutes to obtain the second mixed solution. Next, 0.25 kg of polyacrylic acid adhesive was added to the second mixed solution and stirred at 50 rpm for 30 minutes to obtain the third mixed solution without the need for filtration. The PVDF spray slurry had a D10 of 3.8 μm and a D90 of 35 μm.

[0112] Coating: The prepared PVDF spray slurry was supplied to the spray supply tank by an automated supply system and coated one side of a 9 μm polyethylene wet substrate with a porosity of 50% by the spin spray method. The coating speed was 150 m / min, the number of teeth on the spray dispersion disc was 450, the distance from the rotating disc to the separator substrate was 25 cm, the spray slurry flow rate was 5000 mL / min, and the spray rotation speed was 12000 rpm.

[0113] The spray points were 80 μm for D10 and 600 μm for D90.

[0114] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-2 below.

[0115] Comparative Example 3: Preparation of PVDF aqueous spray slurry: The procedure was the same as in Example 1.

[0116] Coating: The prepared PVDF spray slurry was coated onto one side of a 9 μm polyethylene wet substrate with a porosity of 50% by a spin-spray method. The coating speed was 200 m / min, the spray dispersion disc had 800 teeth, the distance from the rotating disc to the separator substrate was 25 cm, the spray slurry flow rate was 9000 mL / min, and the spray rotation speed was 17000 rpm. The film was dried at 85°C to obtain a polymer-coated separator with secondary aggregates.

[0117] The spray spots obtained after coating were 50 μm for D10 and 300 μm for D90.

[0118] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-2 below.

[0119] Comparative Example 4: Preparation of PVDF aqueous spray slurry: 57 kg of water and 0.0025 kg of dispersant were weighed and stirred at 500 rpm for 30 minutes to obtain the first mixed solution. 5 kg of PVDF-HFP resin (primary particle size 0.15-0.2 μm) was added to the first mixed solution in five portions, with each addition amount being 1 kg. After each addition of PVDF-HFP resin, the mixture was stirred at a low speed of 500 rpm for 30 minutes, then at a high speed of 2500 rpm for 100 minutes, and finally at a low speed of 500 rpm for 30 minutes. The above procedure was repeated until all of the PVDF-HFP resin was uniformly mixed to obtain the second mixed solution. Next, 0.25 kg of polyacrylic acid adhesive was added to the second mixed solution and stirred at 50 rpm for 30 minutes to obtain the third mixed solution. Finally, the mixture was filtered through a 300-mesh filter to obtain a PVDF spray slurry with a D10 of 1.2 μm and a D90 of 5.6 μm.

[0120] Coating: The prepared PVDF spray slurry was coated onto one side of a 9 μm polyethylene wet substrate with a porosity of 50% by a spin-spray method. The coating speed was 200 m / min, the spray dispersion disc had 280 teeth, the distance from the rotating disc to the separator substrate was 25 cm, the spray slurry flow rate was 6000 mL / min, and the spray rotation speed was 4000 rpm. After drying at 85°C, a polymer-coated separator with secondary aggregates was obtained. The spray points were 350 μm for D10 and 1500 μm for D90.

[0121] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-2 below.

[0122] Comparative Example 5: Preparation of PVDF aqueous spray slurry: The process was the same as in Comparative Example 2.

[0123] Coating: Same as in Comparative Example 3.

[0124] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-2 below.

[0125] Comparative Example 6: Preparation of PVDF aqueous spray slurry: The process was the same as in Comparative Example 4.

[0126] Coating: The prepared PVDF spray slurry was coated onto one side of a 9 μm polyethylene wet substrate with a porosity of 50% by a spin-spray method. The coating speed was 300 m / min, the spray dispersion disc had 180 teeth, the distance from the rotating disc to the separator substrate was 15 cm, the spray slurry flow rate was 16000 mL / min, and the spray rotation speed was 4500 rpm. After drying at 85°C, a polymer-coated separator with secondary aggregates was obtained. The spray points were 450 μm for D10 and 2000 μm for D90.

[0127] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-3 below.

[0128] Comparative Example 7: Preparation of PVDF aqueous spray slurry: The process was the same as in Comparative Example 2.

[0129] Coating: The prepared PVDF spray slurry was coated onto one side of a 9 μm polyethylene wet substrate with a porosity of 50% by a spin-spray method. The coating speed was 150 m / min, the spray dispersion disc had 300 teeth, the distance from the rotating disc to the separator substrate was 15 cm, the spray slurry flow rate was 1000 mL / min, and the spray rotation speed was 6000 rpm. After drying at 80°C, a polymer-coated separator with secondary aggregates was obtained. The spray points were D10 at 220 μm and D90 at 1000 μm.

[0130] The deposition state A / B of the PVDF secondary aggregates on the coated separator, the deposition state C / A at the spray points, the effective adhesion area, and the performance and parameters of the separator are shown in Table 1-3 below.

[0131] Test section The PVDF coatings and battery separators in Examples 1-5 and Comparative Examples 1-7 described above were subjected to performance tests, and the test results are shown in Tables 1-1, 1-2, and 1-3 below.

[0132] [Table 1-1] JPEG2026514172000013.jpg164168

[0133] [Table 1-2] JPEG2026514172000014.jpg170167

[0134] [Table 1-3] JPEG2026514172000015.jpg109167

[0135] From the results of the examples and comparative examples, in Examples 1 to 5, A / B, C / A, In Comparative Example 1, all parameters of JPEG2026514172000016.jpg8117 were within the specified range, and the balance between adhesion, ionic conductivity, liquid absorption / retention rate, and powdering rate was effectively maintained, resulting in optimal performance. In Comparative Example 1, an emulsion PVDF-HFP was used that did not have a secondary aggregate structure, had a relatively small A / B ratio, and a relatively large C / A ratio. As a result, although the adhesion was relatively high, the ionic conductivity, liquid absorption, and liquid retention were poor. In Comparative Example 2, during the slurry preparation process, the materials were added all at once and dispersed, and the stirring speed was too low, resulting in poor dispersibility of the powder material in water, and the slurry was not ultimately filtered. Therefore, the PVDF particles in the slurry had a relatively large particle size and a wide distribution range, a relatively large A / B ratio, and a normal C / A ratio. However, both adhesion and ion permeability were poor, the powdering rate was significantly increased, and the powdering of the coating was pronounced. In Comparative Example 3, the secondary aggregates were normal. In Comparative Example 4, a dispersion disc with 800 teeth was used, and the spray rotation speed was set to 17,000 rpm. As a result, the spray point became too small, and although the A / B ratio was normal, the C / A ratio was relatively small. The spray point was high and deposition occurred, and although there was no significant change in adhesive strength, the ionic conductivity decreased significantly, and the powdering rate improved. In Comparative Example 4, PVDF powder was added in five separate additions during the slurry preparation process and stirred at ultra-high speed. PVDF secondary aggregates were present. Due to the low rotation speed and insufficient number of teeth on the rotating disc, the spray point was large, the A / B ratio was relatively small, the C / A ratio was relatively large, both adhesion and ionic conductivity decreased to some extent, and the liquid absorption rate and liquid retention rate decreased significantly. In Comparative Example 5, the secondary aggregates were relatively large, the spray point was small, the A / B ratio was relatively large, the C / A ratio was relatively small, both adhesion and ionic conductivity deteriorated, and the powdering rate increased significantly. In Comparative Example 6, the spray flow rate was too high, the number of teeth on the rotating disc was too low, the coating amount was too large, and the spray point was too large. The JPEG2026514172000017.jpg8117 was too large, resulting in a significant decrease in ionic conductivity. In Comparative Example 7, the spray flow rate was too low, the slurry particle size was relatively large, and the coating amount was small, The image JPEG2026514172000018.jpg8117 was too small, resulting in a significant decrease in the adhesive strength between the coating and the positive and negative electrodes.

[0136] From the results of the examples and comparative examples, A / B, C / A, and High adhesion, high ion permeability, high liquid absorption and retention, and low powdering rate are only possible when all of the parameters in JPEG2026514172000019.jpg8117 are within the specified range.

[0137] Although embodiments of the present invention have been shown and described above, it should be understood that these embodiments are merely illustrative and should not be interpreted as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A polymer-coated separator having secondary aggregates, Separator substrate and A polymer coating applied to at least one side of the separator substrate, The polymer coating includes multiple randomly distributed spray points, each spray point containing multiple polymer secondary aggregates formed from aggregated primary polymer particles. Any spray point within the polymer coating is such that 25 ≤ A / B ≤ 40000 and 100 ≤ C / A ≤ 10 ６ The following conditions are met, however, A represents the projected area of ​​the polymer secondary aggregates within the spray point on the separator substrate. B represents the projected area of ​​the polymer primary particles within the spray point on the separator substrate. C represents the projected area of ​​the spray point on the separator substrate. however, S represents the surface area of ​​the separator substrate. This represents the sum of the projected areas of all polymer secondary aggregates within a spray point on the separator substrate. A polymer-coated separator characterized in that n represents the number of spray points within the S area.

2. 25≦A / B≦10000、2500≦C / A≦5×10 ５ 、 A polymer-coated separator having a secondary aggregate as described in feature 1.

3. The polymer-coated separator has an adhesive strength of ≥ 1 N / m to the ternary positive electrode and an adhesive strength of ≥ 0.5 N / m to the graphite negative electrode, and / or The ionic conductivity of the polymer-coated separator is 80% to 110% of the ionic conductivity of the separator substrate, and / or The polymer-coated separator has a liquid absorption rate of ≥ 70%, a liquid retention rate of ≥ 70%, and / or, A polymer-coated separator having a secondary aggregate according to claim 1, characterized in that the polymer-coated separator has a powdering rate of ≤ 5%.

4. Polymer coatings are 80 to 100 parts by mass of a polymer having secondary aggregates, Adhesive in 2 to 20 parts by mass, A polymer-coated separator having a secondary aggregate according to any one of claims 1 to 3, characterized by comprising 0.01 to 3 parts by mass of a dispersant.

5. The polymer having the secondary aggregates comprises at least one of the following: polyvinylidene fluoride homopolymer, polyvinylidene fluoride-trifluoroethylene copolymer, polyvinylidene fluoride-methyl methacrylate copolymer, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-acrylic acid copolymer, polymethyl methacrylate, polyethylene, and acrylate polymer, and / or The adhesive comprises at least one of carboxymethylcellulose, hydroxyethylcellulose, polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, and / or acrylonitrile multi-component copolymer, The polymer-coated separator having a secondary aggregate according to claim 4, characterized in that the dispersant comprises at least one of ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, acrylic acid-polyurethane, and polyethylene glycol.

6. The separator substrate has a thickness of 3 μm to 25 μm, a porosity of 20% to 80%, and / or A polymer-coated separator having a secondary aggregate according to any one of claims 1 to 3, characterized in that the polymer coating has a thickness of 0.5 μm to 10 μm.

7. A method for producing a polymer-coated separator having a secondary aggregate as described in claim 1, Step S01 involves uniformly mixing a dispersant and water, then adding the polymer in a batch of a portions such that the mass of the polymer added in one batch is 1 / a of the total amount (a ≥ 2), stirring slowly first, then at high speed, then again at low speed, until all the polymer has been added, and finally adding the adhesive and mixing uniformly, followed by filtration to obtain a polymer slurry. Step S01 is, Step S011: Mix water and a dispersant uniformly to obtain a first mixed solution. Step S012 involves adding the polymer to the first mixed solution in a batch, such that the amount of polymer added in one batch is 1 / a of the total amount, and performing a first stage of dispersion with stirring at a rotation speed of 100 rpm to 600 rpm and a stirring time of 10 to 50 minutes until all the polymer has been added, followed by a second stage of dispersion with stirring at a rotation speed of 1000 rpm to 2000 rpm and a stirring time of 30 to 180 minutes, and finally a third stage of dispersion with stirring at a rotation speed of 100 rpm to 600 rpm and a stirring time of 10 to 50 minutes to obtain the second mixed solution, and Step S01 includes step S013, in which the adhesive is added to the second mixed solution and stirred uniformly, and the mixture is filtered through a 40-300 mesh filter to obtain a polymer slurry. Step S02 is to obtain a polymer coating by coating at least one side of a separator substrate with a polymer slurry using a spin spray method, wherein the parameters for the spin spray are: coating speed of 100 m / min to 300 m / min, spray slurry flow rate of 1500 mL / min to 15000 mL / min, spray rotation speed of 5000 rpm to 15000 rpm, number of teeth of the spray rotating disc of 200 to 600, and distance from the rotating disc to the surface of the coating of 20 cm to 50 cm. A manufacturing method characterized by comprising step S03, which involves drying the separator substrate and the polymer coating to obtain a polymer-coated separator having secondary aggregates.

8. A method for producing a polymer-coated separator having a secondary aggregate according to claim 7, characterized in that the polymer slurry has a particle size D10 of 1 μm to 4 μm and a D90 of 6 μm to 20 μm.

9. Polymer application amount: 0.05 g / m² ２ ~1.5 g / m ２ A method for producing a polymer-coated separator having a secondary aggregate according to claim 7, characterized in that it is the same.

10. A method for producing a polymer-coated separator having a secondary aggregate according to claim 7, characterized in that, in step S01, all of the polymer is added, then a grinding process is performed, and finally an adhesive is added and uniformly mixed, and then filtered to obtain a polymer slurry.

11. A battery characterized by comprising a polymer-coated separator having a secondary aggregate as described in any one of claims 1 to 6.

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