Title of Invention: Separator for electrochemical device and method for manufacturing same technical field [One] This application claims priority based on Korean Patent Application No. 10-2018-0116542 filed on September 28, 2018. The present invention relates to a separator for an electrochemical device, and the electrochemical device may be a primary battery or a secondary battery, and the secondary battery includes a lithium ion secondary battery. background [2] BACKGROUND ART Non-aqueous secondary batteries typified by lithium ion secondary batteries are widely used as power sources for portable electronic devices such as notebook computers, mobile phones, digital cameras, and camcorders. Moreover, in recent years, application to automobiles and the like has been studied from the characteristics of these batteries having a high energy density. [3] The simplification of the exterior of a non-aqueous secondary battery is made|formed with size reduction and weight reduction of a portable electronic device. Initially, a battery can made of stainless steel was used as the exterior, but an exterior made of an aluminum can has been developed, and furthermore, a soft pack exterior made of an aluminum laminate pack is also being developed. In the case of a soft pack exterior made of aluminum laminate, since the exterior is flexible, a gap may be formed between the electrode and the separator during charging and discharging, and there is a technical problem that the cycle life is deteriorated. From the viewpoint of solving this problem, a technique for bonding an electrode and a separator is important, and many technical proposals have been made. [4] In addition, in order to manufacture a curved battery, shape deformation is applied, such as bending the electrode assembly in a state in which the separator and the electrode are combined. have. Due to this, an electrochemical reaction does not occur between the electrode and the separator or a dead space with low efficiency is generated, which may cause a problem in which battery performance is deteriorated. [5] Typically, PVdF (Polyvinylidene fluoride)-based resin is used as the binder resin for the electrode adhesive layer, and an adhesive surface layer portion with a high binder resin content is formed near the surface of the inorganic coating layer by migrating the binder resin to the separator surface through a humidified phase separation method. do. However, PVdF-based resins do not have high adhesion to the resin itself, so it is difficult to secure a high level of binding force. In order to improve the adhesive strength, the content of the binder resin may be increased or the coating amount may be increased, but this is not preferable because the thickness of the adhesive layer is increased, the energy density is lowered, and the resistance may be increased. The adhesive layer of the separator should be able to achieve both high adhesion and high ionic conductivity even with a thin thickness. It should be possible to mass-produce at low cost. Accordingly, there is a growing demand for the development of a separator for a secondary battery that satisfies the above requirements. [6] DETAILED DESCRIPTION OF THE INVENTION technical challenge [7] An object of the present invention is to provide a separator including an inorganic coating layer having improved adhesion between an electrode and a separator while having a thin thickness. Another object of the present invention is to provide a method for manufacturing a separator having the above characteristics. It will be readily apparent that other objects and advantages of the present invention may be realized by means or methods and combinations thereof recited in the claims. [8] means of solving the problem [9] The present invention provides a novel separator for an electrochemical device in order to solve the above problems. A first aspect of the present invention relates to the separator, wherein the separator includes a porous polymer substrate and an inorganic coating layer formed on at least one surface of the porous polymer substrate, wherein the inorganic coating layer includes inorganic particles and a binder resin, The binder resin includes a first binder resin including a PVdF-based polymer and a second binder resin including an acrylic polymer, and the acrylic resin has an acid value of 1 or less. [10] In a second aspect of the present invention, in the first aspect, the acrylic polymer has an acid value of 1 or less, and a molecular weight (Mw) of 100,000 to 200,000. [11] A third aspect of the present invention is that in any one of the above aspects, the acrylic polymer has an acid value of 1 or less, a molecular weight (Mw) of 100,000 to 200,000, and a glass transition temperature (Tg) of 90° C. to 130° C. . [12] A fourth aspect of the present invention is any one of the above aspects, wherein the acrylic polymer comprises a (meth)acrylic polymer containing (meth)acrylic acid ester, wherein the monomer is butyl (meth)acrylate, 2- Ethylhexyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, pentyl ( At least one selected from meth) acrylate, n-oxyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, and tetradecyl (meth) acrylate will include [13] A fifth aspect of the present invention is in any one of the above aspects, wherein the acrylic polymer comprises PMMA (Poly (methyl methacrylate)), and the PMMA has a molecular weight (Mw) of 100,000 to 200,000, and an acid value 1 or less, and a Tg of 90°C to 130°C. [14] A sixth aspect of the present invention is that in any one of the above aspects, the acrylic polymer is included in an amount of 10% to 80% by weight of 100% by weight of the binder resin. [15] A seventh aspect of the present invention is that, in any one of the above aspects, the acrylic polymer is included in an amount of 10% to 50% by weight of 100% by weight of the binder resin. [16] An eighth aspect of the present invention is that according to any one of the above aspects, the PVdF polymer comprises at least one of a homopolymer of vinylidene fluoride, a copolymer of vinylidene fluoride and a copolymerizable monomer, and mixtures thereof. . [17] In a ninth aspect of the present invention, in any one of the above aspects, the PVdF polymer has a molecular weight (Mw) of 300,000 or more and 1,000,000 or less. [18] In the tenth aspect of the present invention, in any one of the above aspects, the monomer copolymerizable with vinylidene fluoride is vinyl fluoride, trifluoroethylene (TrFE), chlorofluoroethylene (CTFE), 1,2-difluoro Roethylene, tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkylvinyl)ether, perfluoro(1,3-dioxole) and perfluoro(2,2-dimethyl- 1,3-dioxol) (PDD) is at least one selected from the group consisting of. [19] In an eleventh aspect of the present invention, in any one of the above aspects, an adhesive surface layer portion having a high binder resin content is disposed on the surface of the inorganic coating layer of the separator. [20] A twelfth aspect of the present invention is that, in any one of the above aspects, the separator has an adhesive surface layer having a high content of binder resin disposed on the surface of the inorganic coating layer of the separator through a phase separation method under humidification conditions. [21] A thirteenth aspect of the present invention is that, in any one of the above aspects, the humidification condition is a condition of 40% to 80% relative humidity. [22] A fourteenth aspect of the present invention relates to an electrode assembly for an electrochemical device including an anode, a cathode, and a separator interposed between the anode and the cathode, wherein the separator is according to any one of the aforementioned aspects. [23] A fifteenth aspect of the present invention is a method for manufacturing a separator according to any one of the above aspects, wherein the method includes preparing a porous polymer substrate, applying a slurry for an inorganic coating layer to at least one surface of the porous polymer substrate, and Maintaining the slurry to phase-separate under humidified conditions so that the adhesive surface layer portion having a high binder resin content is disposed on the surface of the inorganic coating layer of the separator. [24] A sixteenth aspect of the present invention is that, in the fifteenth aspect, the humidification condition is a relative humidity of 40% to 80%. [25] Effects of the Invention [26] The separator according to the present invention and the electrochemical device including the same have excellent adhesion between the separator and the electrode, and by using the realized high adhesion, the assembly process of the electrochemical device can be varied. In addition, since the inorganic coating layer and the separation membrane substrate have high peel strength, shrinkage of the separation membrane substrate is prevented by the inorganic coating layer, and thus the thermal stability of the separation membrane is high. Lastly, since the separator can be made thin, it is effective in improving the energy density of the battery. [27] Brief description of the drawing [28] The drawings accompanying the present specification illustrate preferred embodiments of the present invention, and serve to better understand the technical spirit of the present invention together with the above-described content of the present invention, so the present invention is limited only to the matters described in such drawings is not interpreted as On the other hand, the shape, size, scale, or ratio of elements in the drawings included in this specification may be exaggerated to emphasize a clearer description. [29] 1 is a comparison by measuring the Gurley value, resistance, electrode adhesion, and peel strength of separators according to Example 1, Comparative Example 1, and Comparative Example 2. [30] 2 is a comparison of the Gurley value, resistance, electrode adhesion, and peel strength of the separators according to Example 2, Comparative Example 3, and Comparative Example 4 measured. [31] 3a to 3d are SEM images showing the surface shape of the separation membranes prepared in Reference Examples 1a to 1d. [32] 4 is a schematic view showing a cross-sectional structure of a separator according to an embodiment of the present invention. [33] 5 is a diagram illustrating the contents of Table 1; [34] Modes for carrying out the invention [35] Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor appropriately defines the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention based on the principle that it can be done. Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only the most preferred embodiment of the present invention, and do not represent all the technical spirit of the present invention, so they can be substituted at the time of the present application It should be understood that various equivalents and modifications may exist. [36] [37] Throughout this specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated. [38] [39] In addition, the terms "about", "substantially", etc. used throughout this specification are used as meanings at or close to the numerical values ​​when manufacturing and material tolerances inherent in the stated meaning are presented to help the understanding of the present application It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable way. [40] [41] Throughout this specification, the description of “A and/or B” means “A or B or both”. [42] [43] Certain terminology used in the detailed description that follows is for convenience and not limitation. The words 'right', 'left', 'top' and 'bottom' indicate directions in the drawings to which reference is made. The words 'inwardly' and 'outwardly' refer respectively to directions towards or away from the geometric center of the designated device, system, and members thereof. 'Anterior', 'rear', 'above', 'below' and related words and phrases indicate positions and orientations in the drawings to which reference is made and should not be limiting. These terms include the words listed above, derivatives thereof, and words of similar meaning. [44] [45] Meanwhile, unless otherwise indicated in the present specification, the content ratio depends on the weight ratio. [46] [47] The present invention relates to a separator for an electrochemical device and an electrochemical device including the same. In the present invention, the electrochemical device is a device that converts chemical energy into electrical energy by an electrochemical reaction, and is a concept including a primary battery and a secondary battery, and the secondary battery is capable of charging and discharging. , a lithium ion battery, a nickel-cadmium battery, a nickel-hydrogen battery, and the like. [48] [49] 1. Separator [50] 1) Membrane structure [51] The separator according to the present invention includes a porous polymer substrate and an inorganic coating layer formed on at least one surface of the porous polymer substrate. The inorganic coating layer includes inorganic particles and a binder resin, and the binder resin includes a first binder resin including a PVdF-based polymer and a second binder resin including an acrylic polymer having an acid value of 1 or less. In addition, in one embodiment of the present invention, the inorganic coating layer has a high content of the binder resin in the surface layer portion, so that the adhesion between the separator and the electrode is excellent. [52] [53] In one embodiment of the present invention, the separator may have a thickness of 5 μm to 30 μm, and may be appropriately adjusted within the above range. For example, it may be 15 μm or more or 25 μm or less. In addition, the separation membrane will have an air permeability in the range of about 50sec/100cc to 3000sec/100cc. [54] As used herein, the term "permeability" refers to the time for which 100 cc of air permeates to an object for measuring air permeability such as a separator and a porous polymer substrate, and can be used as a unit of second / 100 cc, and the permeability and can be used interchangeably, and is usually expressed as a Gurley value or the like. In a specific embodiment of the present invention, the air permeability may be measured in accordance with JIS P8117. In addition, the air permeability P1 measured in the object having the thickness T1 may be converted to the transmittance P2 when the thickness of the object is 20 μm by the formula: P2 = (P1×20)/T1. [55] On the other hand, in the present invention, the porosity and the pore size are measured using BEL JAPAN's BELSORP (BET equipment) using an adsorbed gas such as nitrogen, or a mercury intrusion porosimetry or capillary flow measurement method ( capillary flow porosimetry). Alternatively, in one embodiment of the present invention, the thickness and weight of the obtained inorganic coating layer may be measured to calculate the porosity from the theoretical density of the inorganic coating layer. [56] [57] 2) Porous polymer substrate [58] The porous polymer substrate refers to a substrate having a plurality of pores formed therein as an ion-conducting barrier that passes ions while blocking electrical contact between the negative electrode and the positive electrode. The pores have a structure connected to each other so that gas or liquid can pass from one side of the substrate to the other side. [59] As the material constituting such a porous polymer substrate, either an organic material having electrical insulation or an inorganic material can be used. In particular, from the viewpoint of imparting a shutdown function to the substrate, it is preferable to use a thermoplastic resin as a constituent material of the substrate. Here, the shutdown function refers to a function of preventing thermal runaway of the battery by blocking the movement of ions by dissolving the thermoplastic resin and closing the pores of the porous substrate when the battery temperature is high. As the thermoplastic resin, a thermoplastic resin having a melting point of less than 200°C is suitable, and polyolefin is particularly preferable. [60] In addition, polymer resins such as polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalene It may further include at least any one of. The porous polymer substrate may be a nonwoven fabric, a porous polymer film, or a laminate of two or more thereof, but is not particularly limited thereto. [61] [62] Specifically, the porous polymer substrate is any one of the following a) to e). [63] [64] a) a porous film formed by melting/extruding a polymer resin; [65] b) a multilayer film in which two or more layers of the porous film of a) are laminated; [66] c) a nonwoven web prepared by integrating filaments obtained by melting/spinning a polymer resin; [67] d) a multilayer film in which two or more layers of the nonwoven web of b) are laminated; [68] e) A porous composite membrane having a multilayer structure comprising at least two of a) to d). [69] [70] In the present invention, the porous polymer substrate preferably has a thickness of 3 μm to 12 μm or 5 μm to 12 μm. If the thickness thereof is less than the above value, the function of the conductive barrier is not sufficient. On the other hand, if the thickness is excessively exceeded (ie, too thick), the resistance of the separator may excessively increase. [71] In one embodiment of the present invention, the polyolefin preferably has a weight average molecular weight of 100,000 to 5,000,000. When the weight average molecular weight is smaller than 100,000, it may become difficult to ensure sufficient mechanical properties. Moreover, when it becomes larger than 5 million, the shutdown characteristic may worsen, or shaping|molding may become difficult. In addition, the puncture strength of the porous polymer substrate may be 300 gf or more from the viewpoint of improving the manufacturing yield. The piercing strength of a porous substrate refers to the maximum piercing load (gf) measured by performing a piercing test under the conditions of a radius of curvature of the needle tip of 0.5 mm and a piercing speed of 2 mm/sec using a Kato tech KES-G5 handy compression tester. [72] In a specific embodiment of the present invention, the porous polymer substrate can be used as long as it is a planar porous polymer substrate used in electrochemical devices, for example, has high ion permeability and mechanical strength, and the pore diameter is generally 10 nm to An insulating thin film having a thickness of 100 nm and generally 5 μm to 12 μm may be used. [73] [74] 3) Inorganic coating layer [75] In the present invention, the separator includes an inorganic coating layer formed on at least one surface of the porous polymer substrate. The inorganic coating layer includes a mixture including a binder resin and inorganic particles. In one embodiment of the present invention, the inorganic coating layer may be filled with inorganic particles in a dense state inside the layer, and may have a plurality of micropores resulting from the interstitial volume formed between the inorganic particles. These micropores have a structure connected to each other, and may represent a porous structure in which gas or liquid can pass from one surface to the other. In one embodiment of the present invention, all or at least a portion of the surface of the inorganic particles is coated with a binder resin, and may be surface-bonded and/or point-bonded with each other through the binder resin. In one embodiment of the present invention, the inorganic particles may be included in the inorganic coating layer in a ratio of 50% by weight or more relative to 100% by weight of the total amount of the binder resin and the inorganic particles, preferably the inorganic particles are 60% by weight or more or 70% by weight % or 80% by weight or more. In addition, it may be included in 95 wt% or less or 90 wt% or less within the above range. [76] [77] The inorganic coating layer preferably has a thickness of 1 μm to 5 μm on one side of the porous polymer substrate. The thickness may be preferably 3 µm or more, and the adhesion to the electrode is excellent within the numerical range, and as a result, the cell strength of the battery is increased. On the other hand, if the thickness is 4 μm or less, it is advantageous in terms of cycle characteristics and resistance characteristics of the battery. [78] [79] On the other hand, in the present invention, the inorganic coating layer is provided with an electrode bonding portion having a high content of the binder resin on the surface portion from the characteristics of the manufacturing method to be described later. 4 is a schematic view showing the cross-sectional structure of the separator 100 according to an embodiment of the present invention. Referring to this, in the separator of the present invention, the inorganic coating layer 120 is formed on the surface of the porous polymer substrate 110, and the binder resin is distributed in a high concentration in the surface layer portion of the inorganic coating layer compared to other portions. In the present specification, for convenience of description, a portion of the surface layer in which the binder resin is distributed in a high concentration is referred to as 'electrode adhesive part 121'. In one embodiment of the present invention, the electrode bonding portion is according to the result of migration of the binder resin to the surface layer portion by a manufacturing method such as humidified phase separation. Therefore, the electrode bonding portion is not physically separated from the inorganic coating layer, but is integrally and inseparably coupled to the surface of the inorganic coating layer as a part of the inorganic coating layer, and the thickness thereof may be uneven. In one embodiment of the present invention, a portion containing 70 wt% or more, preferably 85 wt% or more of the binder resin from the top based on the thickness of the inorganic coating layer may be divided into the electrode bonding portion. [80] [81] B. Material of inorganic coating layer [82] B1. binder resin [83] In one embodiment of the present invention, the inorganic coating layer includes a PVdF-based polymer serving as a first binder resin and an acrylic polymer serving as a second binder resin, wherein the acrylic polymer has an acid value of 1 or less. [84] [85] In the present invention, the PVdF-based polymer may include at least one of a homopolymer of vinylidene fluoride (ie, polyvinylidene fluoride), a copolymer of vinylidene fluoride and a copolymerizable monomer, and a mixture thereof. In one embodiment of the present invention, as the monomer, for example, a fluorinated monomer and/or a chlorine-based monomer may be used. Non-limiting examples of the fluorinated monomer include vinyl fluoride; trifluoroethylene (TrFE); chlorofluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); perfluoro(alkylvinyl)ethers such as perfluoro(methylvinyl)ether (PMVE), perfluoro(ethylvinyl)ether (PEVE), and perfluoro(propylvinyl)ether (PPVE); perfluoro(1,3-dioxole); and perfluoro(2,2-dimethyl-1,3-dioxole) (PDD), and at least one of them may be included. In one embodiment of the present invention, the PVDF-based polymer resin may include PVDF, PVDF-HFP, PVDF-CTFE, and the like, and may include at least one selected from among them. In a specific embodiment of the present invention, the PVDF-based polymer may have a molecular weight (Mw) of 300,000 to 1,000,000. For example, the PVDF-based polymer may have a molecular weight (Mw) of 800,000 or less within the above range. [86] [87] The acrylic polymer has a molecular weight (Mw) of 100,000 to 200,000, an acid value of 1 or less, and a glass transition temperature (Tg) of 90°C to 130°C. [88] [89] If the molecular weight exceeds the above range and is too high, a problem may occur in that the inorganic particles are not well dispersed during the preparation of the slurry for forming the inorganic coating layer. Since the polymer content is low, there is a problem in that electrode adhesion is reduced. In addition, if the Tg does not fall within the above range, the morphology is easily deformed even if the phase separation occurs properly and a desired surface morphology is achieved, which causes a decrease in adhesive force. In addition, when the acid value is high, the affinity between the binder resin and the inorganic particles is increased, so that the mobility of the polymer is reduced by the inorganic particles, thereby reducing the phase separation efficiency. Accordingly, the amount of the binder moving to the surface layer can be reduced. In the present invention, the molecular weight may be measured by weight average molecular weight (Mw) by gel permeation chromatography (GPC: gel permeation chromatography, PL GPC220, Agilent Technologies). In the present invention, the unit of the molecular weight may be g/mol. [90] Meanwhile, in the present invention, the acrylic polymer may be included in an amount of 10% to 80% by weight of 100% by weight of the binder resin. On the other hand, in terms of forming an electrode bonding portion through phase separation, the acrylic polymer is preferably included in an amount of 50 wt% or less. When the content of the PVdF polymer resin decreases due to an increase in the content of the acrylic polymer, the absolute amount of the PVdF polymer resin that can be distributed in the surface layer decreases, and the movement of the PVdF polymer resin may be restricted by the acrylic polymer. . 3A to 3D show the humidified phase separation results according to the content ratio of the PVdF-based polymer and the acrylic polymer, PMMA, of Reference Examples 1a to 1d. Referring to this, it can be seen that as the content ratio of PMMA in the binder resin increases, the result of the humidified phase separation decreases. [91] In the present specification, the acid value is mg of KOH required to neutralize free fatty acids contained in the resin in 1 g, and the unit is KOH-mg/g. The acid value can be calculated by the following formula. [92] [93] (ceremony) [94] Acid value = A x N xfx KOH consumption (mL)/S [95] [96] where A is the molecular weight of KOH, N is the concentration of the KOH standard solution, f is the titer of the 0.1N KOH solution, and S is the amount of resin used (g). [97] In the present invention, the acrylic polymer may include, for example, a (meth)acrylic polymer. The (meth)acrylic polymer contains (meth)acrylic acid ester as a monomer, and these monomers are butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylic Rate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, n-oxyl (meth) acrylate, isooctyl (meth) acrylic Monomers such as late, isononyl (meth) acrylate, lauryl (meth) acrylate, and tetradecyl (meth) acrylate may be exemplified and may include one or two or more of them. [98] [99] In a preferred embodiment of the present invention, the acrylic polymer comprises PMMA (Poly (methyl methacrylate)), wherein the PMMA has a molecular weight (Mw) of 100,000 to 200,000, and an acid value of 1 or less. , Tg is from 90 ℃ to 130 ℃. [100] [101] In addition, in one embodiment of the present invention, the inorganic coating layer may further include additives such as a dispersant and/or a thickener in the range of 1% to 3% by weight based on 100% by weight of the inorganic coating layer. In one embodiment of the present invention, the additive is polyvinylpyrrolidone (PVP), polyvinylalcohol (PVA), hydroxy ethyl cellulose (HEC), hydroxy propyl cellulose Woods (hydroxy propyl cellulose, HPC), ethylhydroxy ethyl cellulose (EHEC), methyl cellulose (MC), carboxymethyl cellulose (CMC), hydroxyalkyl methyl cellulose Rose (hydroxyalkyl methyl cellulose) and cyanoethylene polyvinyl alcohol may be used by selecting one or more appropriate ones. [102] [103] B2. mineral particles [104] In a specific embodiment of the present invention, the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as oxidation and/or reduction reactions do not occur in the operating voltage range of the applied electrochemical device (eg, 0-5V based on Li/Li+). In particular, when inorganic particles having a high dielectric constant are used as the inorganic particles, the ionic conductivity of the electrolyte can be improved by contributing to an increase in the degree of dissociation of an electrolyte salt, such as a lithium salt, in a liquid electrolyte. [105] For the above reasons, the inorganic particles preferably include high dielectric constant inorganic particles having a dielectric constant of 5 or more, preferably 10 or more. Non-limiting examples of inorganic particles having a dielectric constant of 5 or more include BaTiO 3 , Pb(Zr,Ti)O 3 (PZT), b 1-x La x Zr 1-y Ti y O 3 (PLZT, 0