Separator for electrochemical device, method for manufacturing same, and electrochemical device including same

Abstract

The present disclosure relates to a separator for an electrochemical device, a method of manufacturing the same, and an electrochemical device including the same, and more particularly, to a separator for an electrochemical device, a method of manufacturing the same, and an electrochemical device including the same, in which different binders are used in a coating layer of the separator to form a pattern, and thus, the separator reduces the difference between the positive electrode adhesive strength and the negative electrode adhesive strength, improves wetting, and reduces resistance.

Description

Technical Field

[0001] This disclosure claims priority and benefit to Korean Patent Applications Nos. 10-2023-0148006 and 10-2024-0148548, filed with the Korean Intellectual Property Office on October 31, 2023 and October 28, 2024, respectively, the entire contents of which are incorporated herein by reference.

[0002] This disclosure relates to a separator for an electrochemical device, a method for manufacturing the separator, and an electrochemical device including the separator. Specifically, this disclosure relates to a separator for an electrochemical device that uses different adhesives in a coating and patterns the coating to reduce the difference between the positive and negative electrode adhesion strengths, improve wetting, and reduce resistance, as well as a method for manufacturing the separator and an electrochemical device including the separator. Background Technology

[0003] In the components of an electrochemical device, a separator comprises a porous polymer substrate located between the positive and negative electrodes. It separates the positive and negative electrodes and serves to prevent electrical short circuits between the two electrodes while allowing the electrolyte and ions to pass through. The separator itself does not participate in the electrochemical reaction; however, physical properties such as electrolyte liquid wetting, porosity, and thermal shrinkage affect the performance and safety of the electrochemical device.

[0004] Therefore, to enhance the physical properties of the separator, coatings are added to porous polymer substrates, and various methods are explored to modify the properties of the coating by adding various materials. For example, inorganic substances can be added to the coating to improve the mechanical strength of the separator, or inorganic substances or hydrates can be added to the coating to improve the flame retardancy and heat resistance of the polymer substrate.

[0005] The separator can be attached to the electrode by a lamination process, and to ensure the adhesive strength between the electrode and the separator, a polymer adhesive can be added to the composition of the coating used to form the separator.

[0006] Meanwhile, the adhesion strength to the electrodes can vary depending on the composition of the polymer adhesive, and there is a problem that the electrochemical device may fold due to the asymmetry of the adhesion strength between the positive and negative electrodes.

[0007] Furthermore, when existing polymer adhesives have strong adhesion strength to both the positive and negative electrodes, the wetting of the electrolyte liquid decreases, which may increase the resistance of the electrochemical device.

[0008] Therefore, there is a need for research into technologies that can minimize the asymmetry of the adhesion strength with the positive and negative electrodes while maintaining a certain level of adhesion strength with both electrodes. Summary of the Invention

[0009] Technical issues

[0010] This disclosure relates to a separator for an electrochemical device, wherein an adhesive with different adhesive strengths to the positive and negative electrodes is used in the coating, and the coating is patterned to prevent separator folding caused by asymmetry in adhesive strength to the positive and negative electrodes and to reduce resistance caused by reduced wetting, as well as a method for manufacturing the separator and an electrochemical device including the separator.

[0011] However, the problems addressed by this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the following description other problems not mentioned.

[0012] Technical solution

[0013] One embodiment of this disclosure provides a separator for an electrochemical device, the separator comprising: a porous polymer substrate; and a coating disposed on at least one surface of the porous polymer substrate and comprising a first polymer binder, a second polymer binder, and inorganic particles, wherein a first surface portion of the first polymer binder and a second surface portion comprising the second polymer binder are alternately disposed on the surface of the coating.

[0014] According to one embodiment of this disclosure, the first polymeric adhesive may be a fluoropolymer adhesive.

[0015] According to one embodiment of this disclosure, the second polymeric adhesive may be a hybrid polymer of a fluoropolymeric adhesive and an acryloyl polymeric adhesive.

[0016] According to one embodiment of this disclosure, the area of ​​the second surface portion can be 40% or less based on the total surface area of ​​the coating.

[0017] According to one embodiment of this disclosure, the positive electrode adhesion strength of the first surface portion can be greater than the positive electrode adhesion strength of the second surface portion.

[0018] According to one embodiment of this disclosure, the negative electrode adhesion strength of the second surface portion can be greater than that of the negative electrode adhesion strength of the first surface portion.

[0019] According to one embodiment of this disclosure, the coating may have an average thickness of 0.5 μm or greater and 1.0 μm or less.

[0020] According to one embodiment of this disclosure, the content of the first polymeric adhesive may be 10 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the coating.

[0021] According to one embodiment of this disclosure, the content of the second polymer adhesive may be 10 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the coating.

[0022] One embodiment of this disclosure provides a method for manufacturing a separator for an electrochemical device, the method comprising providing a coating by alternately coating a first slurry comprising a first polymeric adhesive and a second slurry comprising a second polymeric adhesive on at least one surface of a porous polymer substrate, wherein a first surface portion of the first polymeric adhesive and a second surface portion comprising the second polymeric adhesive are alternately disposed on the surface of the coating.

[0023] According to one embodiment of this disclosure, the coating can be provided using gravure coating, spraying, slot die coating, bar coating, or roller coating.

[0024] According to one embodiment of this disclosure, the loading of the first slurry used for coating can be greater than 7 g / m³. 2 And 10 g / m 2 Or smaller.

[0025] According to one embodiment of this disclosure, the loading amount of the second slurry used for coating can be 4 g / m³. 2 Or larger and 7 g / m 2 Or smaller.

[0026] One embodiment of this disclosure provides an electrochemical device comprising: a positive electrode; a negative electrode; and the aforementioned separator disposed between the positive electrode and the negative electrode.

[0027] Beneficial effects

[0028] According to one embodiment of the present disclosure, a separator for an electrochemical device uses an adhesive with different adhesion strengths to the positive and negative electrodes in the coating and the coating is patterned to suppress the increase in resistance caused by reduced wetting while maintaining the adhesion strength to the positive and negative electrodes.

[0029] According to one embodiment of the present disclosure, a method for manufacturing a separator for an electrochemical device forms a coating with a constant thickness and a constant pattern by controlling the load during coating, thereby reducing the increase in resistance caused by reduced wetting while maintaining the adhesion strength to the positive and negative electrodes. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating a partition according to one embodiment of the present disclosure.

[0031] Figure 2This is an image showing the coated surface of Embodiment 1 of this disclosure.

[0032] Figure 3 This is an image showing the coated surface of Embodiment 2 of this disclosure.

[0033] Figure 4 This is an image showing the coated surface of Comparative Example 1 of the present disclosure.

[0034] Figure 5 This is an image showing the coated surface of Comparative Example 2 of the present disclosure.

[0035] Figure 6 This is an image showing the coated surface of Comparative Example 3 of the present disclosure.

[0036] Figure 7 This is an image showing the coated surface of Comparative Example 4 of the present disclosure.

[0037] Figures 8a to 8f The wetting states of Examples 1 and 2 and Comparative Examples 1 to 4 of this disclosure are shown in sequence. Detailed Implementation

[0038] In this specification, the description of a part as "including" certain components means that it may further include other components and does not exclude other components unless otherwise specifically stated.

[0039] In this specification, "A and / or B" means "A and B, or A or B".

[0040] In this specification, the description provided "on a component" means that another component may be placed further therein, and does not exclude another component being placed therein, unless otherwise specifically stated otherwise.

[0041] In this specification, the property of "having holes" means that an object comprises multiple holes and that gas and / or liquid fluids can be transferred from one side of the object to the other through the structure of interconnected holes.

[0042] In this specification, the separator has a porous nature including multiple pores and performs the function of a porous ion-conducting barrier that allows ions to pass through while blocking the electrical contact between the negative and positive electrodes in an electrochemical device.

[0043] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The drawings may be exaggerated, omitted, or shown schematically in order to describe or emphasize embodiments of the present disclosure.

[0044] The contents of this disclosure will be described in more detail below.

[0045] One embodiment of this disclosure provides a separator 100 for an electrochemical device, the separator comprising: a porous polymer substrate 110; and a coating 130 disposed on at least one surface of the porous polymer substrate and comprising a first polymer binder, a second polymer binder, and inorganic particles, wherein a first surface portion 131 comprising the first polymer binder and a second surface portion 133 comprising the second polymer binder are alternately disposed on the surface of the coating.

[0046] According to one embodiment of this disclosure, a separator for an electrochemical device uses an adhesive with different adhesion strengths to the positive and negative electrodes in its coating and the coating is patterned to reduce the increase in resistance caused by reduced wetting while maintaining adhesion strength to the positive and negative electrodes.

[0047] According to one embodiment of the present disclosure, a separator for an electrochemical device can improve the adhesive strength between a polymer substrate and a coating by improving the adhesion between inorganic particles and a polymer binder.

[0048] Figure 1 This is a schematic diagram of a separator 100 for an electrochemical device according to one embodiment of the present disclosure. (Refer to...) Figure 1 Specifically, a separator 100 for an electrochemical device is described as one embodiment of this disclosure.

[0049] According to one embodiment of this disclosure, the porous polymer substrate 110 can be prepared using a polyolefin-based resin as the base resin. Examples of polyolefin-based resins may include polyethylene, polypropylene, polypentene, etc., and the polyolefin-based resin may include one or more types thereof. A porous separator prepared using such a polyolefin-based resin as the base resin, i.e., a separator having multiple pores, can provide a shut-off function at an appropriate temperature.

[0050] According to one embodiment of this disclosure, the polyolefin-based resin may have a weight-average molecular weight of 500,000 or greater and 1,500,000 or less. By adjusting the weight-average molecular weight of the polyolefin-based resin within the above range, the compression resistance of the separator can be improved. Furthermore, when using different types of polyolefin-based resins after mixing or forming a separator with a multilayer structure formed of different types of polyolefin-based resins, the weight-average molecular weight of the polyolefin-based resin can be calculated by adding the weight-average molecular weights of each of the polyolefin-based resins according to the content ratio.

[0051] In this disclosure, the weight-average molecular weight (Mw) can be measured by gel permeation chromatography (GPC: gelpermeation chromatography, PL GPC220, Agilent Technologies), and the measurement conditions can be set as follows.

[0052] -Column: PL Olexis (Polymer Laboratories)

[0053] Solvent: TCB (trichlorobenzene)

[0054] - Flow rate: 1.0 ml / min

[0055] - Sample concentration: 1.0 mg / ml

[0056] Injection volume: 200 μl

[0057] - Column temperature: 160 ℃

[0058] - Detector: Agilent high-temperature RI detector

[0059] - Standard: Polystyrene (corrected by a third-order function)

[0060] According to one embodiment of the present disclosure, the porous polymer substrate 110 can be prepared by a method (wet process) in which a polyolefin-based resin is mixed with plasticizers at a high temperature to form a single phase, the polymer material and plasticizers are phase-separated during a cooling process, the plasticizers are then extracted to form pores, and elongation and thermosetting treatments are performed.

[0061] According to one embodiment of this disclosure, by adjusting the mixing ratio of plasticizers, elongation ratio, thermosetting temperature, etc., those skilled in the art can easily prepare a partition 100 having an average pore size and a maximum pore size that conforms to this disclosure.

[0062] According to one embodiment of this disclosure, the porous polymer substrate 110 may have a thickness of 1 μm or greater and 30 μm or less. Specifically, the porous polymer substrate 110 may have a thickness of 2 μm or greater and 28 μm or less, 3 μm or greater and 26 μm or less, 4 μm or greater and 24 μm or less, 5 μm or greater and 22 μm or less, 6 μm or greater and 20 μm or less, 7 μm or greater and 18 μm or less, 8 μm or greater and 16 μm or less, 9 μm or greater and 14 μm or less, or 9 μm or greater and 12 μm or less. By adjusting the thickness of the porous polymer substrate within the above ranges, the volume of the electrochemical device can be minimized, and the positive and negative electrodes can be electrically insulated.

[0063] According to one embodiment of this disclosure, a separator 100 for an electrochemical device includes a coating 130 disposed on at least one surface of a porous polymer substrate 110. Specifically, the separator 100 for the electrochemical device includes a coating 130 disposed on one or both surfaces of the porous polymer substrate 110. By including a coating 130 disposed on at least one surface of the porous polymer substrate 110 as described above, the separator's heat resistance is improved, its mechanical properties are improved, and short circuits in the electrodes caused by the shrinkage of the separator at high temperatures can be prevented.

[0064] According to one embodiment of this disclosure, coating 130 includes a first polymer binder, a second polymer binder, and inorganic particles. The coating 130, comprising the first polymer binder, the second polymer binder, and inorganic particles as described above, improves the heat resistance and mechanical properties of the separator, prevents electrical short circuits in the electrodes caused by separator shrinkage at high temperatures, and allows the formation of pores within the coating.

[0065] According to one embodiment of this disclosure, a coating can be formed using a composition comprising a mixture of inorganic particles and a polymer binder. By using the coating-forming composition comprising a mixture of inorganic particles and a polymer binder as described above, the ease of operation for forming the coating can be improved, and the viscosity of the composition for forming the coating can be easily adjusted.

[0066] According to one embodiment of this disclosure, the composition for forming a coating may further include a solvent. By further including a solvent in the composition for forming a coating as described above, the ease of operation for forming the coating can be improved, and the mixture of inorganic particles and polymer binder can be uniformly dispersed in the composition for forming the coating. In this specification, solvent may refer to a dispersion medium, and an emulsion in which the mixture of inorganic particles and polymer binder is dispersed by a solvent may refer to a composition for forming a coating.

[0067] According to one embodiment of this disclosure, the solvent may be one or a combination thereof selected from the group consisting of water, acetone, ethanol, isopropanol (IPA), dimethylacetamide (DMAc), dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and acetonitrile. Specifically, water is preferred as the solvent. By selecting a solvent from the above, the viscosity of the composition used to form the coating can be controlled, and the dispersibility of the inorganic particles and polymer binder in the solvent can be improved.

[0068] According to one embodiment of this disclosure, the composition for forming the coating may further include additives. By further including additives as described above, the adhesive force of the inorganic particles is improved, and the dispersibility of the composition for the inorganic coating can be improved.

[0069] According to one embodiment of this disclosure, the additive may include dispersants, surfactants, defoamers, flame retardants, adhesion promoters, etc. By selecting additives from the above, the dispersibility and phase stability of the composition used for inorganic coatings can be improved, air bubbles can be removed or flame retardancy can be increased, adhesion strength can be improved, and wetting of the polymer substrate and the composition used to form the coating can be improved.

[0070] According to one embodiment of this disclosure, the dispersant may include any one or more selected from polyacrylic acid, oil-soluble polyamines, oil-soluble amine compounds, fatty acids, fatty alcohols, sorbitol fatty acid esters, tannic acid, and pyrogallol. Preferably, the dispersant may be sodium carboxymethyl cellulose (CMC Na). By selecting a dispersant from the above, the dispersibility and phase stability of the composition used for coating can be improved.

[0071] According to one embodiment of this disclosure, the content of the dispersant relative to 100 parts by weight of the composition for forming the coating can be greater than 0 parts by weight and 5 parts by weight or less. Specifically, the content of the dispersant relative to 100 parts by weight of the composition for forming the coating can be greater than 0 parts by weight and 4 parts by weight or less, 1 part by weight or greater and 3 parts by weight or less, or 1 part by weight or greater and 2 parts by weight or less. By adjusting the content of the dispersant within the above ranges, the dispersibility and phase stability of the composition for forming the coating can be improved.

[0072] According to one embodiment of this disclosure, coating 130 includes a plurality of pores. Specifically, coating 130 includes a plurality of micropores. The plurality of pores may be multiple micropores created by the dense filling of the gap volume formed between the inorganic particles by the coating with inorganic particles and a polymer binder included in the polymer binder mixture. These micropores are interconnected and obtain a porous structure that allows gas or liquid to pass from one side surface to the other side surface. With coating 130 including a plurality of pores as described above, electrolyte liquid in the battery, described later, is allowed to permeate the separator.

[0073] According to one embodiment of this disclosure, the inorganic particles are not particularly limited, provided they are electrochemically stable. In other words, the inorganic particles are not particularly limited, provided they do not undergo oxidation and / or reduction reactions within the operating voltage range of the applied electrochemical device (e.g., 0 V to 5 V based on Li / Li⁺). In particular, when inorganic particles with ion transfer capabilities are used, performance improvements can be provided by increasing the ionic conductivity in the electrochemical device. Additionally, when inorganic particles with high dielectric constants are used, the ionic conductivity of the electrolyte liquid can be improved by promoting an increase in the degree of dissociation of the electrolyte salt (such as lithium salt) in the liquid electrolyte. The inorganic particles may include high dielectric constant inorganic particles with a dielectric constant of 5 or greater and 10 or greater, inorganic particles with lithium-ion transfer capabilities, or mixtures thereof. Specifically, the inorganic particles may be selected from BaSO₄, BaTiO₃, Pb(Zr,Ti)O₃ (PZT), b₁-xLa₁xZr₁-yTiyO₃ (PLZT, 0 <x<1、0<y<1)、Pb(Mg 1 / 3 Nb 2 / 3The group consisting of one or more of the following: PbTiO3 (PMN-PT), hafnium dioxide (HfO2), SrTiO3, SnO2, CeO2, MgO, Mg(OH)2, NiO, CaO, ZnO, ZrO2, SiO2, Y2O3, Al2O3, SiC, Al(OH)3, TiO2, aluminum peroxide, zinc tin hydroxide (ZnSn(OH)6), zinc stannate (Zn2SnO4, ZnSnO3), antimony trioxide (Sb2O3), antimony tetroxide (Sb2O4), antimony pentoxide (Sb2O5), and boehmite (AlO(OH)). However, these are merely examples, and inorganic particles are not limited thereto.

[0074] According to one embodiment of this disclosure, the average particle size (D50) of the inorganic particles (not shown) is not particularly limited, but is preferably in the range of 0.3 μm or larger and 1 μm or smaller, for forming a coating 130 with uniform thickness and appropriate porosity. Specifically, when the average particle size is less than 0.3 μm, the dispersibility of the inorganic particles in the slurry used to prepare the coating can be reduced, and when the average particle size is greater than 1 μm, the thickness of the formed coating may be increased.

[0075] In this specification, "D" 50 "Particle size" refers to the particle size at the 50% point of the cumulative distribution of particle size. Particle size can be measured using a laser diffraction method. Specifically, the powder to be measured is dispersed in a dispersion medium and then introduced into a commercially available laser diffraction particle size measurement device (e.g., Microtrac S3500). As the particles pass through the laser beam to calculate the particle size distribution, the measurement depends on the differences in the diffraction pattern of the particle size. 50 Particle size can be measured by calculating the particle size at the 50% point of the cumulative distribution of particle number based on the particle size in the measuring device.

[0076] According to one embodiment of this disclosure, the content of inorganic particles relative to 100 parts by weight of the composition for coating can be 70 parts by weight or more and 90 parts by weight or less. Specifically, the content of inorganic particles relative to 100 parts by weight of the composition for coating can be 75 parts by weight or more and 90 parts by weight or less, 77 parts by weight or more and 89 parts by weight or less, 79 parts by weight or more and 88 parts by weight or less, 80 parts by weight or more and 87 parts by weight or less, 82 parts by weight or more and 86 parts by weight or less, or 84 parts by weight or more and 86 parts by weight or less. By adjusting the content of inorganic particles within the above ranges, the insulation and heat resistance of the separator can be improved, and separator shrinkage at high temperatures can be prevented.

[0077] According to one embodiment of this disclosure, a first surface portion 131 including a first polymeric adhesive and a second surface portion 133 including a second polymeric adhesive are alternately disposed on the surface of the coating 130. As described above, by alternately disposing the first surface portion 131 including the first polymeric adhesive and the second surface portion 133 including the second polymeric adhesive on the surface of the coating 130, a constant adhesive strength with the electrode can be maintained by including portions with different adhesive strengths for the positive and negative electrodes, and wetting with the electrolyte liquid can also be improved.

[0078] According to one embodiment of this disclosure, the first polymeric adhesive and the second polymeric adhesive can be particulate adhesives or solvent adhesives. Specifically, particulate adhesives have the property of maintaining their original particulate shape without deformation even when dispersed in a solvent, and for example, polyvinylidene polymers or acrylic polymers can be used. Solvent adhesives are soluble in polar solvents including water, and for example, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), or polyacrylamide (PAM) can be used. Preferably, the first polymeric adhesive and the second polymeric adhesive can be particulate adhesives.

[0079] According to one embodiment of this disclosure, the first polymeric adhesive may be a fluoropolymeric adhesive. By selecting a fluoropolymeric adhesive as the first polymeric adhesive as described above, the porosity of the separator can be maintained, and the adhesive strength can be maintained even when the coating is wetted by the electrolyte liquid after the battery has been activated.

[0080] According to one embodiment of this disclosure, the second polymeric binder may be a hybrid polymer of a fluoropolymeric binder and an acryloyl polymeric binder. By selecting a hybrid polymer of a fluoropolymeric binder and an acryloyl polymeric binder as the second polymeric binder, the wetting of the electrolyte liquid can be improved, and the battery resistance can be reduced.

[0081] According to one embodiment of this disclosure, the fluoropolymer adhesive may be a PVDF-based polymer adhesive. A PVDF-based polymer is a polymer that includes vinylidene fluoride as a polymerization unit. PVDF-based polymers may include homopolymers of vinylidene fluoride (i.e., polyvinylidene fluoride), copolymers of vinylidene fluoride and another polymerizable monomer (comonomer), or mixtures of two or more thereof.

[0082] The comonomer can be one or more types selected from the group consisting of tetrafluoroethylene, hexafluoropropylene, trifluoroethylene, chlorofluoroethylene, 1,2-difluoroethylene, perfluoro(methyl vinyl) ether, perfluoro(ethyl vinyl) ether, perfluoro(propyl vinyl) ether, difluoro(1,3-m-dioxacyclopentene), perfluoro(2,2-dimethyl-1,3-m-dioxacyclopentene), trichloroethylene, and vinyl fluoride. Non-limiting examples of PVDF-based polymers may include polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-trichloroethylene copolymer, polyvinylidene fluoride-tetrafluoroethylene copolymer, polyvinylidene fluoride-trifluoroethylene copolymer, polyvinylidene fluoride-trifluorochloroethylene copolymer, polyvinylidene fluoride-ethylene copolymer, etc., and may use one type selected from these, or a mixture of two or more types. Preferably, the PVDF-based polymer can be a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP).

[0083] In this specification, the content of comonomers in vinylidene fluoride polymer resins can be measured using a Varian 500 MHz 1H NMR method. For detailed measurement methods, please refer to the Journal of Materials Chemistry, 2012, 22, 341 or AMT-3412-0k. To identify the NMR spectra, appropriate equipment such as a Bruker Avance III HD 700 MHz NMR or a Varian 500 MHz NMR can be used.

[0084] According to one embodiment of this disclosure, the acryloyl polymer adhesive is a polymer comprising a carboxylic acid ester as a repeating unit, and may specifically be a (meth)acrylate. More specifically, (meth)acrylates can be one or a combination thereof selected from the group consisting of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, nonyl methacrylate, decyl methacrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, ethylene glycol methacrylate, di(ethylene glycol) methacrylate, di(propylene glycol) methacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, allyl methacrylate, and di(ethylene glycol) methacrylate. Preferably, the (meth)acrylate is one or more selected from methyl (meth)acrylate, ethyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.

[0085] According to one embodiment of this disclosure, the second polymeric adhesive may include a PVDF-based polymeric adhesive and an acryloyl-based polymeric adhesive. Preferably, the second polymeric adhesive may include polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) and an acryloyl-based adhesive, and may include these in a weight ratio of 5:5 to 7:3. Preferably, the weight ratio may be 5:5.

[0086] According to one embodiment of this disclosure, the acryloyl polymer resin may be a copolymer comprising styrene and acrylate in a weight ratio of 5:5 to 7:3. According to one embodiment of this disclosure, the acrylate copolymerized with styrene may be butyl acrylate.

[0087] According to one embodiment of this disclosure, the first polymeric adhesive may be a fluoropolymeric adhesive, which may be the same as the fluoropolymer included in the second polymeric adhesive.

[0088] According to one embodiment of this disclosure, the area of ​​the second surface portion can be 40% or less, based on the total surface area of ​​the coating. Specifically, based on the total surface area of ​​the coating, the area of ​​the second surface portion can be greater than 0% and 40% or less, 5% or greater and 40% or less, 10% or greater and 40% or less, 15% or greater and 40% or less, 20% or greater and 40% or less, 22% or greater and 40% or less, 24% or greater and 40% or less, or 25% or greater and 40% or less. When the area of ​​the second surface portion is less than the above ranges, the area of ​​the first surface portion increases, reducing the adhesion strength with the negative electrode; and when the area of ​​the second surface portion is greater than the above ranges, the adhesion strength with the positive electrode may decrease. By adjusting the area of ​​the second surface portion based on the total surface area of ​​the coating as described above, the wetting of the electrolyte liquid can also be improved, while simultaneously increasing the adhesion strength with both the positive and negative electrodes.

[0089] According to one embodiment of this disclosure, the positive electrode adhesion strength of the first surface portion can be greater than that of the second surface portion. Specifically, the first polymer adhesive included in the first surface portion can have a superior positive electrode adhesion strength than the second polymer adhesive included in the second surface portion. By adjusting the positive electrode adhesion strength of the first surface portion to be greater than that of the second surface portion, a constant adhesion strength with the positive electrode is ensured, and the asymmetry between the positive and negative electrode adhesion strengths can be mitigated.

[0090] According to one embodiment of this disclosure, the negative electrode adhesion strength of the second surface portion can be greater than that of the first surface portion. Specifically, the second polymer adhesive included in the second surface portion can have a superior negative electrode adhesion strength than the first polymer adhesive included in the first surface portion. By adjusting the negative electrode adhesion strength of the second surface portion to be greater than that of the first surface portion as described above, a constant adhesion strength with the negative electrode is ensured, and the asymmetry between the positive and negative electrode adhesion strengths can be mitigated.

[0091] According to one embodiment of this disclosure, the difference in dry adhesion strength between the positive and negative electrodes can be 50 gf / 20 mm or less. Specifically, the difference in dry adhesion strength between the positive and negative electrodes can be 0 gf / 20 mm or greater and 50 gf / 20 mm or less, or 0 gf / 20 mm or greater and 32 gf / 20 mm or less. By adjusting the difference in dry adhesion strength between the positive and negative electrodes within the above ranges, battery stability can be improved.

[0092] According to one embodiment of this disclosure, the difference in wet adhesion strength between the positive and negative electrodes in the coating can be 25 gf / 20 mm or less. Specifically, the difference in wet adhesion strength between the positive and negative electrodes in the coating can be 0 gf / 20 mm or greater and 25 gf / 20 mm or less, or 0 gf / 20 mm or greater and 15 gf / 20 mm or less. By adjusting the difference in wet adhesion strength between the positive and negative electrodes within the above ranges, battery stability can be improved.

[0093] According to one embodiment of this disclosure, the coating may have an average thickness of 0.5 μm or greater and 1.0 μm or less. When the coating becomes thicker than the average thickness range, the battery resistance may increase. Furthermore, when the average thickness is greater than the aforementioned range, the area to be adhered after the lamination process increases, and therefore, the wetting of the electrolyte liquid can be reduced; and when the average thickness is less than the aforementioned range, the area to be adhered after the lamination process decreases, and therefore, the adhesion strength can be reduced.

[0094] In one embodiment of this disclosure, a contact-type thickness measuring device can be used to measure the thickness of polymer substrates, coatings, etc. As an example of a contact-type thickness measuring device, the VL-50S-B manufactured by Mitutoyo Corporation can be used.

[0095] According to one embodiment of this disclosure, the content of the first polymeric adhesive may be 10 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the coating. Specifically, the content of the first polymeric adhesive may be 11 parts by weight or more and 14 parts by weight or less relative to 100 parts by weight of the coating. By adjusting the content of the first polymeric adhesive within the above ranges, wetting and adhesive strength can be improved.

[0096] According to one embodiment of this disclosure, the content of the second polymeric adhesive may be 10 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the coating. Specifically, the content of the second polymeric adhesive may be 11 parts by weight or more and 14 parts by weight or less relative to 100 parts by weight of the coating. By adjusting the content of the second polymeric adhesive within the above ranges, wetting and adhesive strength can be improved.

[0097] One embodiment of this disclosure provides a method for manufacturing a separator for an electrochemical device, the method comprising providing a coating by alternately coating a first slurry comprising a first polymeric adhesive and a second slurry comprising a second polymeric adhesive on at least one surface of a porous polymer substrate, wherein a first surface portion of the first polymeric adhesive and a second surface portion comprising the second polymeric adhesive are alternately disposed on the surface of the coating.

[0098] A method for manufacturing a separator for an electrochemical device according to one embodiment of the present disclosure forms a coating with a constant thickness and a constant pattern by controlling the load during coating, and can suppress the increase in resistance caused by reduced wetting while maintaining the adhesion strength to the positive and negative electrodes.

[0099] A method for manufacturing a separator 100 for an electrochemical device will be specifically described as one embodiment of this disclosure. Furthermore, portions overlapping with the description provided for the separator in an electrochemical device will not be included in this specification.

[0100] According to one embodiment of this disclosure, the coating can be applied using gravure coating, spraying, slot die coating, bar coating, or roller coating. Preferably, the coating can be applied using gravure coating.

[0101] According to one embodiment of this disclosure, the loading of the first slurry used for coating can be greater than 7 g / m³. 2 And 10 g / m 2 Or less. When the load is greater than the above range, the area to be adhered increases after the lamination process, and therefore the wetting of the electrolyte liquid can be reduced. When the load is less than the above range, the area to be adhered decreases after the lamination process, and therefore the adhesion strength can be reduced.

[0102] According to one embodiment of this disclosure, the loading amount of the second slurry used for coating can be 4 g / m³. 2 Or larger and 7 g / m 2 Or less. When the load is greater than the above range, the area to be adhered increases after the lamination process, and therefore the wetting of the electrolyte liquid can be reduced. When the load is less than the above range, the area to be adhered decreases after the lamination process, and therefore the adhesion strength can be reduced.

[0103] One embodiment of this disclosure provides an electrochemical device comprising: a positive electrode; a negative electrode; and either a separator disposed between the positive electrode and the negative electrode.

[0104] An electrochemical device according to an embodiment of the present disclosure includes a coating formed with a constant pattern using different polymer binders, and thus, the adhesion strength to the positive electrode and the negative electrode can be improved while improving the wetting of the electrolyte liquid.

[0105] According to an embodiment of the present disclosure, a positive electrode is provided with a positive electrode current collector and a positive electrode active material layer on at least one surface of the positive electrode current collector, and the positive electrode active material layer includes a positive electrode active material, a conductor, and an adhesive resin. The positive electrode active material may include a type of layered compound or a compound substituted with one or more transition metals, such as lithium manganese composite oxides (LiMn2O4, LiMnO2, etc.), lithium cobalt oxide (LiCoO2), or lithium nickel oxide (LiNiO2); lithium manganese oxides, such as the chemical formula of Li 1+x Mn 2-x O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, or LiMnO2); lithium copper oxide (Li2CuO2); vanadium oxides, such as LiV3O8, LiV3O4, V2O5, or Cu2V2O7; Ni-site type lithium nickel oxides represented by the chemical formula of LiNi 1-x M x O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3); lithium manganese composite oxides represented by the chemical formula of LiMn 1-x M x O2 (where M = Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu, or Zn); LiMn2O4 in which some Li in the chemical formula is substituted with alkaline earth metal ions; disulfide compounds; and Fe2(MoO4)3, or a mixture of two or more types thereof.

[0106] According to an embodiment of the present disclosure, a negative electrode is provided with a negative electrode current collector and a negative electrode active material layer on at least one surface of the negative electrode current collector, and the negative electrode active material layer includes a negative electrode active material, a conductor, and an adhesive resin. The negative electrode may include, as the negative electrode active material, one type selected from the following: lithium metal oxides; carbon, such as non-graphitizable carbon or graphite-based carbon; Li x Fe2O3 (0 ≤ x ≤ 1), Li x WO2 (0 ≤ x ≤ 1); silicon-based materials, such as Si, SiO x (0 < x < 2), SiC, and Si alloys; metal composite oxides, such as Sn x Me 1-x Me' y O z(Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of Groups 1, 2, and 3 of the periodic table, halogens; 0 < x ≤ 1, 1 ≤ y ≤ 3, 1 ≤ z ≤ 8); lithium metal; lithium alloy; tin-based alloy; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5; conductive polymers such as polyacetylene; Li-Co-Ni-based materials; and titanium oxide, or a mixture of two or more types thereof.

[0107] According to one embodiment of the present disclosure, the positive electrode current collector and / or the negative electrode current collector are not particularly limited as long as they have high conductivity without causing chemical changes in the electrochemical device, and specifically, stainless steel, copper, aluminum, nickel, titanium, carbonaceous electrodes, or aluminum or stainless steel whose surface is treated with carbon, nickel, titanium, silver, etc. can be used.

[0108] According to one embodiment of the present disclosure, the conductor can be any one selected from the group consisting of graphite, carbon black, carbon fiber or metal fiber, metal powder, conductive whisker, conductive metal oxide, carbon nanotube, activated carbon, and polyphenylene derivative, or a mixture of two or more types of conductive materials. The carbon nanotube has a graphite sheet in the shape of a cylinder with a nanoscale diameter and has a sp2 bonding structure, and exhibits the properties of a conductor or a semiconductor depending on the angle and structure at which the graphite sheet is rolled. According to the number of bonds forming the wall, the carbon nanotube can be classified into single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), and multi-walled carbon nanotube (MWCNT), and these carbon nanotubes can be appropriately selected according to the application of the dispersion. More specifically, the conductor can be one type selected from the group consisting of natural graphite, artificial graphite, conductive agent (super-p), acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, conductive carbon black (denka), aluminum powder, nickel powder, zinc oxide, potassium titanate, and titanium oxide, or a mixture of two or more types of conductive materials.

[0109] According to one embodiment of this disclosure, as the adhesive resin, an adhesive resin commonly used in electrodes in the art can be used. Non-limiting examples of such adhesive resins may include polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethyl methacrylate, polyethylhexyl acrylate, polybutyl acrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetatebutyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, and cyanoethyl sucrose. Examples of amylopectin include sucrose, amylopectin (pullulan), and carboxyl methyl cellulose, but these are not limited to.

[0110] According to one embodiment of this disclosure, the electrode assembly includes a positive electrode, a negative electrode, and a separator inserted between the positive and negative electrodes, and the electrochemical device can be manufactured by inserting the electrode assembly into a suitable housing and injecting an electrolyte liquid therein.

[0111] According to one embodiment of this disclosure, the electrolyte liquid is obtained by dissolving or dissociating a salt having a structure such as A⁺B⁻ in an organic solvent, wherein A⁺ comprises ions consisting of alkali metal cations such as Li⁺, Na⁺, or K⁺ or combinations thereof, and B⁻ comprises anions such as PF⁻, BF⁻, Cl⁻, Br⁻, I⁻, ClO⁻, AsF⁻, CH₃CO₂⁻, CF₃SO₃⁻, N(CF₃SO₂)₂ in the organic solvent. - Or C(CF2SO2)3 - The ions are composed of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), γ-butyrolactone, or mixtures thereof; however, the electrolyte liquid is not limited thereto.

[0112] One embodiment of this disclosure provides a battery module including a battery comprising electrode assemblies as a unit cell; a battery pack including the battery module; and a device including the battery pack as a power source. Specific examples of the device may include a power tool powered by an electric motor; electric vehicles, including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.; electric two-wheeled bicycles, including electric bicycles (E-bikes) and electric scooters (E-scooters); electric golf carts; systems for power storage, etc., but are not limited thereto.

[0113] Invention patterns

[0114] The present disclosure will be described in detail below with reference to embodiments in order to specifically describe the present disclosure. However, embodiments based on the present disclosure can be modified in various different forms, and the scope of the present disclosure is not to be construed as limited to the embodiments described below. Embodiments of this specification are provided to describe the present disclosure more fully to those skilled in the art.

[0115] <Example 1>

[0116] Polyethylene resin (weight average molecular weight 900,000) was extruded, and a porous polymer substrate (total thickness approximately 9 μm, porosity 40% by volume) was prepared using a wet process.

[0117] Al₂O₃ powder with a D50 particle size of 400 nm was prepared as inorganic particles. A copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP) (LBG4430LX, Arkema) was prepared as the first polymer binder, and sodium carboxymethyl cellulose (CMC Na) (SG-L02, GL Chem.) was prepared as a dispersant. The inorganic particles, the first polymer binder, and the dispersant prepared above were added to water at a weight ratio of 85:14:1, and then the inorganic particles were crushed and dispersed to prepare a first slurry for coating.

[0118] Al₂O₃ powder with a D50 particle size of 400 nm was prepared as inorganic particles. An acrylic emulsion (CSB-130, ToyoInk Co., Ltd.) and a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP) (LBG4430LX, Arkema) were prepared as a second polymer binder, and sodium carboxymethyl cellulose (CMC Na) (SG-L02, GL Chem.) was prepared as a dispersant. The inorganic particles, the second polymer binder (acrylic emulsion:PVdF-HFP = 5:5), and the above-prepared dispersant were added to water at a weight ratio of 85:14:1. The inorganic particles were then crushed and dispersed to prepare a second slurry for coating.

[0119] A first slurry and a second slurry are alternately applied and coated onto a porous polymer substrate using a gravure coating method, and then dried to form a coating with a thickness of 0.5 μm or greater and 1.0 μm or less. Here, the loading of the first slurry is 9.5 g / m³. 2 Furthermore, the loading rate of the second slurry is 4.5 g / m³. 2 As a result, the area of ​​the second surface portion is 25% ( Figure 2 ).

[0120] <Example 2>

[0121] The coating was prepared in the same manner as in Example 1, except that the loading of the first slurry was 7.5 g / m³. 2 Furthermore, the loading rate of the second slurry is 6.5 g / m³. 2 As a result, the area of ​​the second surface portion is 40% ( Figure 3 ).

[0122] <Comparative Example 1>

[0123] A coating is prepared in which only the second slurry is used to form a pattern instead of the first slurry in Example 1. Figure 4 ).

[0124] <Comparative Example 2>

[0125] The coating was prepared in the same manner as in Example 1, except that the loading of the first slurry was 6.5 g / m³. 2 Furthermore, the loading rate of the second slurry is 7.5 g / m³. 2 As a result, the area of ​​the second surface portion is 60% ( Figure 5 ).

[0126] <Comparative Example 3>

[0127] The coating was prepared in the same manner as in Example 1, except that the coating thickness was adjusted to 1.5 μm. Figure 6 ).

[0128] <Comparative Example 4>

[0129] The coating was prepared in the same manner as in Example 1, except that an acrylamide emulsion (CSB-130, Toyo Ink Co., Ltd.) was used instead of the copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP) (LBG4430LX, Arkema). Figure 7 ).

[0130] [Table 1]

[0131]

[0132] [Measurement of coating surface area]

[0133] To measure the area of ​​the coated surface portion of Examples 1 and 2 and Comparative Examples 1 to 4, the surface EDAX F-peak was analyzed and the area was measured.

[0134] According to Figures 2 to 7 To identify the area of ​​the coated surface portion of each of Examples 1 and 2 and Comparative Examples 1 to 4.

[0135] <Preparation of Electrochemical Devices>

[0136] 1) Preparation of the positive electrode

[0137] The positive electrode active material (LiNi) 0.8 Mn 0.1 Co 0.1O2), conductor (carbon black), dispersant N-methylpyrrolidone (ADC-01, LG Chem.), and binder resin (a mixture of PVDF-HFP and PVDF) were mixed with water at a weight ratio of 97.5:0.7:0.14:1.66 to prepare a slurry for the positive electrode active material layer, wherein the components other than water had a concentration of 50% by weight. The slurry was then coated on the surface of an aluminum film (10 μm thick) and dried to prepare a positive electrode with a positive electrode active material layer (120 μm thick).

[0138] 2) Preparation of the negative electrode

[0139] Graphite (a blend of natural and artificial graphite), conductor (carbon black), dispersant polyvinylpyrrolidone (Junsei Chemical Co., Ltd., Japan), and binder resin (a mixture of PVDF-HFP and PVDF) were mixed with water at a weight ratio of 97.5:0.7:0.14:1.66 to prepare a slurry for the negative electrode active material layer, wherein the components other than water had a concentration of 50% by weight. The slurry was then coated onto the surface of a copper thin film (10 μm thick) and dried to prepare a negative electrode with a negative electrode active material layer (120 μm thick).

[0140] <Experimental Example>

[0141] [Measurement of dry bond strength]

[0142] The separators of each of the examples and comparative examples were cut to dimensions of 70 mm (length) × 20 mm (width), and the electrodes and separators were laminated using a press at 60 °C, 6.5 MPa, and 1 second to prepare samples. The prepared samples were attached to a glass plate for fixation using double-sided tape, with the electrodes positioned facing the glass plate. The separator portions of the samples were peeled off at 180° angle and a rate of 150 mm / min at 25 °C, and the strength of each of the positive and negative electrodes was measured. The results are summarized in Table 2 below.

[0143] [Measurement of wet bond strength]

[0144] The separators of each of the examples and comparative examples were cut to dimensions of 70 mm (length) × 20 mm (width), and the electrodes and separators were laminated using a press at 60 °C, 6.5 MPa, and 1 second to prepare samples. The prepared samples were loaded into a battery casing along with an electrolyte liquid and kept for 4 hours to impregnate the samples with the electrolyte liquid. As the electrolyte liquid, LiPF6 was prepared by mixing ethylene carbonate and ethyl methyl carbonate in a volume ratio of 7:3 and at a concentration of 1M. Subsequently, the samples were removed from the casing and then attached to a glass plate for fixation using double-sided tape, with the electrodes positioned facing the glass plate. The separator portion of the sample was peeled off at 25 °C at a 90° angle and a rate of 200 mm / min, and the strength of each of the positive and negative electrodes was measured. The results are summarized in Table 2 below.

[0145] [Resistance Measurement]

[0146] Each separator is inserted between SUS and electrolyte liquid is injected to manufacture a coin cell, and the resistance (ER) is measured using the EIS method. Here, the frequency is set to the range of 100,000 Hz to 10,000 Hz.

[0147] [Table 2]

[0148]

[0149] According to Table 2, it can be recognized that in Examples 1 and 2, which include a second surface area of ​​40% or less, the dry bond strength of the positive and negative electrodes and the wet bond strength of the positive and negative electrodes are both excellent, and the resistance is low.

[0150] In contrast, Comparative Example 1 only includes the second polymer on the surface portion of the coating without forming a pattern, resulting in poor positive electrode adhesion strength and increased resistance compared to the example.

[0151] It can be seen that Comparative Example 2 has a second surface portion area greater than 40%, resulting in poor positive electrode adhesion strength, and Comparative Example 2 also has the problems of poor wet adhesion strength and increased resistance compared to the embodiment.

[0152] Comparative Example 3 has a coating thickness greater than 0.5 μm to 1.0 μm, and although the adhesion strength is advantageous, it has the problem of a significant increase in resistance.

[0153] Comparative Example 4 used an acrylamide adhesive as the first polymer adhesive, which caused an increase in resistance due to the formation of a film when impregnated with an electrolyte liquid.

[0154] [Measurement of Wettability]

[0155] Each separator of the examples and comparative examples was immersed in the electrolyte liquid, and placed vertically after the lamination process, and the extent to which the electrolyte liquid was drawn in by the capillary phenomenon was measured.

[0156] Figures 8a to 8f The wetting states of Examples 1 and 2 and Comparative Examples 1 to 5 of this disclosure are shown in sequence.

[0157] according to Figures 8a to 8f It can be recognized that, with Figures 8c to 8f Compared to the comparative examples, Figure 8a and Figure 8b It exhibits excellent wetting properties because the electrolyte liquid is absorbed to a greater extent.

[0158] [Comparison of adhesive strength between positive and negative electrodes]

[0159] [Table 3]

[0160]

[0161] According to Table 3, the first polymer adhesive has superior positive electrode adhesion strength compared to the second polymer adhesive. Therefore, when the adhesives are alternately arranged on the coating according to the present disclosure, the first polymer adhesive can exhibit superior positive electrode adhesion strength.

[0162] Furthermore, compared to the first polymer adhesive, the second polymer adhesive has superior negative electrode adhesion strength. Therefore, when the adhesives are alternately arranged on the coating according to the present disclosure, the second polymer adhesive can exhibit superior negative electrode adhesion strength.

[0163] Therefore, a separator for an electrochemical device according to one embodiment of the present disclosure can prevent increased resistance by improving wetting, while improving dry bond strength and wet bond strength by alternately arranging the first surface portion and the second surface portion on the coating surface, controlling the surface area, and controlling the type of adhesive.

[0164] [Figure Labels]

[0165] 100: partition

[0166] 110: Porous polymer substrate

[0167] 130: Coating

[0168] 131: First surface portion

[0169] 133: Second surface portion

Claims

1. A separator for an electrochemical device, the separator comprising: Porous polymer substrate; and A coating is disposed on at least one surface of the porous polymer substrate and comprises a first polymer binder, a second polymer binder, and inorganic particles. This includes a first surface portion of the first polymer adhesive and a second surface portion of the second polymer adhesive alternately disposed on the surface of the coating.

2. The partition according to claim 1, wherein the first polymer adhesive is a fluoropolymer adhesive.

3. The separator according to claim 1, wherein the second polymer adhesive is a hybrid polymer of a fluoropolymer adhesive and an acryloyl polymer adhesive.

4. The partition according to claim 1, wherein the area of ​​the second surface portion is 40% or less based on the total surface area of ​​the coating.

5. The separator according to claim 1, wherein the positive electrode bonding strength of the first surface portion is greater than the positive electrode bonding strength of the second surface portion.

6. The separator according to claim 1, wherein the negative electrode bonding strength of the second surface portion is greater than the negative electrode bonding strength of the first surface portion.

7. The partition according to claim 1, wherein the coating has an average thickness of 0.5 μm or greater and 1.0 μm or less.

8. The partition according to claim 1, wherein the content of the first polymeric adhesive is 10 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the coating.

9. The partition according to claim 1, wherein the content of the second polymer adhesive is 10 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the coating.

10. A method for manufacturing a separator for an electrochemical device, the method comprising: A coating is provided by alternately coating at least one surface of a porous polymer substrate with a first slurry comprising a first polymeric adhesive and a second slurry comprising a second polymeric adhesive. This includes a first surface portion of the first polymer adhesive and a second surface portion of the second polymer adhesive alternately disposed on the surface of the coating.

11. The method of claim 10, wherein the coating is provided using gravure coating, spraying, slot die coating, bar coating, or roller coating.

12. The method of claim 10, wherein the loading of the first slurry for coating is greater than 7 g / m³. 2 And 10 g / m 2 Or smaller.

13. The method of claim 10, wherein the loading of the second slurry for coating is 4 g / m³. 2 Or larger and 7 g / m 2 Or smaller.

14. An electrochemical device, comprising: positive electrode; negative electrode; as well as A separator according to claim 1 is inserted between the positive electrode and the negative electrode.

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