Electrode assembly and electrochemical device including same

Abstract

The present invention relates to: a novel structure of an electrode assembly applicable to a process of manufacturing an electrode assembly by sequentially stacking a positive electrode, a separator, and a negative electrode through lamination and stacking; and a method for manufacturing same. The electrode assembly according to one aspect of the present invention, due to the characteristic structure of an uppermost separator, has the advantage of significantly mitigating scratching of the uppermost separator that can occur when transferring the electrode assembly to a subsequent process after manufacturing same.

Description

Electrode assembly and electrochemical device including the same

[0001] The present invention relates to an electrode assembly for an electrochemical device and an electrochemical device including the same.

[0002] This application claims priority to Korean Patent Application No. 2024-0104163, filed with the Korean Intellectual Property Office on August 5, 2024, the entire disclosure of which is incorporated herein by reference.

[0003] Secondary batteries, most notably lithium-ion secondary batteries, are widely used as power sources for portable electronic devices such as laptops, mobile phones, digital cameras, and camcorders. Furthermore, these batteries have recently been applied to a variety of fields, including automobiles, due to their high energy density.

[0004] The safety assessment and assurance of electrochemical devices, such as lithium-ion secondary batteries, are crucial. Regarding the safety characteristics of electrochemical devices, there is a significant risk of explosion if the device overheats, causing thermal runaway or if the separator is punctured. In particular, polyolefin-based separator substrates, commonly used as separators in electrochemical devices, exhibit extreme thermal shrinkage at temperatures above 100°C due to the material properties and manufacturing process characteristics, including stretching, which can cause short circuits between the anode and cathode.

[0005] To address the safety concerns of such electrochemical devices, a separator has been proposed that forms a porous coating layer by coating at least one surface of a membrane substrate with inorganic particles and a binder polymer. A separator formed with a porous coating layer using inorganic particles and a binder polymer has the characteristic of stably bonding a cathode and anode to each side of the membrane during the electrochemical device manufacturing process due to its surface adhesive strength.

[0006] However, in the process of manufacturing a stack cell through the L&S (Lamination & Stacking) process, which sequentially stacks and laminates anode / separator / cathode / separator, and then transporting it through a conveyor belt for subsequent packaging, there is a problem that the stack cell may be damaged during the manufacturing process due to friction caused by the adhesive force of the separator within the stack cell, so improvement is needed.

[0007] Referring to Figure 1, a plurality of stack cells are transported while being stacked in the thickness direction, and there is a problem that the uppermost separator is damaged due to friction caused by vibration, etc.

[0008] Therefore, the problem that the present invention seeks to solve is:

[0009] When manufacturing an electrochemical device using the L&S process, the present invention aims to provide a novel electrode assembly structure and a method for manufacturing the same, which reduces damage to a separator during a series of processes (automatic logistics) from manufacturing a stack cell during the assembly process to moving it to packaging, thereby enhancing the stability of the electrochemical device manufactured.

[0010] To solve the above problem,

[0011] According to one aspect of the present invention, electrode assemblies of the following embodiments are provided.

[0012] An electrode assembly according to the first embodiment comprises:

[0013] At least one first electrode laminate comprising a first separator, a first electrode, a second separator, and a second electrode sequentially laminated in the thickness direction,

[0014] A second electrode laminate comprising a third separator, a third electrode, and a fourth separator sequentially laminated in the thickness direction,

[0015] The second electrode stack has a structure in which the third separator is stacked on the top of the one or more first electrode stacks so that it comes into contact with the second electrode stack,

[0016] The fourth separator comprises a separator substrate and a first porous coating layer including first inorganic particles and a first binder resin on one surface of the separator substrate, and the content of the first binder resin in the first porous coating layer is 20 wt% or less.

[0017] According to the second embodiment, in the first embodiment,

[0018] Two or more of the above first electrode laminates are continuously laminated in the thickness direction,

[0019] It may have a structure in which the second electrode laminate is laminated on the top of the first electrode laminate.

[0020] According to the third embodiment, in the first embodiment or the second embodiment,

[0021] The content of the first binder resin in the first porous coating layer may be 5 wt% or less.

[0022] According to the fourth embodiment, in any one of the first to third embodiments,

[0023] The above first porous coating layer may be formed on the back surface of the surface where the fourth separator comes into contact with the third electrode.

[0024] According to the fifth embodiment, in any one of the first to fourth embodiments,

[0025] The interface between the first separator and the first electrode,

[0026] The interface between the first electrode and the second separator,

[0027] The interface between the second separator and the second electrode,

[0028] The interface between the second electrode and the third separator,

[0029] The interface between the third separator and the third electrode, and

[0030] At least one interface among the interfaces between the third electrode and the fourth separator may include one or more types of adhesive binders.

[0031] According to the sixth embodiment, in any one of the first to fifth embodiments,

[0032] A concentration gradient may be formed from the surface of the adjacent electrode to the surface of the adjacent separator so that the concentration of the adhesive binder included in at least one interface becomes lower the closer it is to the adjacent separator.

[0033] According to the seventh embodiment, in any one of the first to sixth embodiments,

[0034] It may be possible that at least one interface does not have a concentration gradient of the adhesive binder in the thickness direction.

[0035] According to the eighth embodiment, in any one of the first to seventh embodiments,

[0036] The above adhesive binder may include a fluorine-based binder.

[0037] According to the ninth embodiment, in any one of the first to eighth embodiments,

[0038] The first separator, the second separator, and the third separator each independently include a separator substrate, and a second porous coating layer formed on at least one surface of the separator substrate,

[0039] The second porous coating layer includes second inorganic particles and a second binder resin,

[0040] The above first binder resin includes a non-fluorine-based binder,

[0041] The above second binder resin may include a fluorine-based binder.

[0042] According to the tenth embodiment, in any one of the first to ninth embodiments,

[0043] The second porous coating layer has a content gradient of the second binder resin in which the content of the second binder resin increases from the lower part adjacent to the separator substrate to the upper part, which is the outermost part of the separator.

[0044] The first porous coating layer of the fourth separator may not have a concentration gradient of the first binder resin.

[0045] According to the eleventh embodiment, in any one of the first to tenth embodiments,

[0046] The second porous coating layer may have a multilayer structure including an inorganic particle layer including second inorganic particles formed on the surface of an adjacent separator substrate, and a binder layer including a second binder resin formed on the surface of the inorganic particle layer.

[0047] According to the 12th embodiment, in any one of the 1st to 11th embodiments,

[0048] The fourth separator is formed on a surface in contact with the third electrode and further includes a second porous coating layer including second inorganic particles and a second binder resin.

[0049] The surface adhesion of the first porous coating layer is 1 gf / 15 mm or less,

[0050] The surface adhesion of the second porous coating layer may be 5 gf / 15 mm or more.

[0051]

[0052] According to another aspect of the present invention, a method for manufacturing an electrode assembly of the following embodiments is provided.

[0053] A method for manufacturing an electrode assembly according to the 13th embodiment is as follows:

[0054] A step of preparing a first electrode assembly by sequentially stacking a first separator, a first electrode, a second separator, and a second electrode in the thickness direction;

[0055] A step of preparing a second electrode laminate by sequentially laminating a third separator, a third electrode, and a fourth separator in the thickness direction, and

[0056] A step of sequentially stacking one or more of the first electrode assemblies and stacking a second electrode assembly on the top,

[0057] The fourth separator includes a separator substrate and a first porous coating layer including first inorganic particles and a first binder resin on an upper surface of the separator substrate, and the content of the first binder resin in the first porous coating layer may be 20 wt% or less.

[0058] According to the 14th embodiment, in the 13th embodiment,

[0059] It further includes a step of preparing the first separator, the second separator, and the third separator,

[0060] The first separator, the second separator, and the third separator each include a separator substrate and a second porous coating layer formed on at least one surface of the separator substrate,

[0061] The composition of the second porous coating layer may be different from the composition of the first porous coating layer.

[0062]

[0063] According to another aspect of the present invention, electrochemical devices of the following embodiments are provided.

[0064] The electrochemical device according to the 15th embodiment,

[0065] It may include an electrode assembly according to any one of the first to twelfth embodiments.

[0066] Since the electrode assembly according to one embodiment of the present invention does not have an uppermost adhesive force, it can exhibit the effect of preventing and minimizing damage to the separator at the uppermost part of the electrode assembly caused by vibration of a transport means such as a conveyor belt when transporting to a subsequent process.

[0067] This can have the effect of dramatically improving the fire stability of electrochemical devices, but the effect of the present invention is not limited to this.

[0068] Figure 1 is a photograph showing damage such as scratches that occurred on the uppermost separator during the process of transporting the electrode assembly of Comparative Example 1 in this specification through a circular logistics system.

[0069] Figure 2 is a schematic diagram of an electrode assembly (1) according to one embodiment of the present invention.

[0070] Figure 3 is a schematic diagram of a fourth separation membrane (203) according to one embodiment of the present invention.

[0071] Fig. 4 is a schematic diagram of an electrode assembly according to one embodiment of the present invention. Fig. 4 illustrates a structure in which an adhesive binder (501) is included at the interface between the electrode and the separator.

[0072] Fig. 5 is a schematic diagram of a second separation membrane (103) according to one embodiment of the present invention. Fig. 5 illustrates a structure in which a second porous coating layer (1032) is provided on both sides of a separation membrane substrate (1030).

[0073] Hereinafter, the present invention will be described in detail.

[0074] In this specification, when a part is said to "include" a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless otherwise specifically stated.

[0075] In this specification, the term “A and / or B” means “A or B, or both.”

[0076] In this specification, words indicating directions such as up and down are for convenience only and are not intended to limit the present invention.

[0077] The present invention relates to an electrode assembly for an electrochemical device and a method for manufacturing the same. In the present invention, the electrochemical device is a device that converts chemical energy into electrical energy through an electrochemical reaction, and includes a primary battery and a secondary battery. The secondary battery is capable of being charged and discharged, and encompasses lithium-ion batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and the like.

[0078]

[0079] [Electrode assembly]

[0080] An electrode assembly according to one aspect of the present invention includes a structure in which at least two electrode laminates having different structures are laminated in the thickness direction.

[0081] In this specification, the 'thickness direction' refers to the direction in which the negative electrode, separator, and positive electrode are laminated within the electrode assembly.

[0082] Fig. 2 is a schematic diagram of an electrode assembly (1) according to one embodiment of the present invention. Referring to Fig. 2, the direction in which n first electrode laminates (10) are laminated within the electrode assembly (1) and the direction in which the second electrode laminates are laminated are referred to as the thickness direction of the electrode assembly.

[0083] According to one aspect of the present invention, the electrode assembly (1) includes at least one first electrode laminate (10) including a first separator (101), a first electrode (102), a second separator (103), and a second electrode (104) sequentially laminated in the thickness direction. The first electrode and the second electrode have different polarities, for example, when the first electrode is an anode, the second electrode is a cathode, and when the first electrode is a cathode, the second electrode is an anode. In the present specification, a first electrode laminate having different polarities laminated with a separator interposed therebetween may also be referred to as a mono cell.

[0084] According to one aspect of the present invention, the electrode assembly (1) includes a second electrode laminate (20) including a third separator (201), a third electrode (202), and a fourth separator (203) sequentially laminated in the thickness direction on the first electrode laminate (10). The third electrode has a polarity different from that of the second electrode. For example, when the second electrode is a cathode, the third electrode is an anode, and when the second electrode is an anode, the third electrode is a cathode. In the present specification, a second electrode laminate in which only an electrode having one polarity is interposed between separators as described above may also be referred to as a half cell.

[0085] In one embodiment of the present invention, the first electrode, the second electrode, and the third electrode may each be an anode or a cathode, as described above. Since the specific configurations of the anode and cathode can be conventional, a description thereof will be omitted.

[0086] In the present specification, a structure in which at least one monocell and one halfcell are sequentially stacked may also be referred to as a stacked cell. The stacked cell may have a different number of stacked monocells depending on the specifications of the electrochemical device used, and may include, for example, n monocells and one halfcell, wherein n may be an integer greater than or equal to 1. For example, depending on the specifications of the electrochemical device, n may be 1 to 200, 5 to 150, 10 to 100, 15 to 90, 20 to 80, 25 to 70, 30 to 60, or 40 to 50, and is not particularly limited in number.

[0087] An electrode assembly according to one aspect of the present invention has a structure in which one or more first electrode laminates are sequentially laminated, and a second electrode laminate is laminated on the uppermost end of the first electrode laminate. In addition, the electrode assembly may have a structure in which two or more first electrode laminates are sequentially laminated, and the second electrode laminate is laminated on the uppermost end of the first electrode laminate.

[0088] At this time, the second electrode stack is stacked in a direction in which the uppermost part of the first electrode stack and the third separator come into contact. Accordingly, the fourth separator is positioned at the uppermost part of the electrode assembly. In other words, the fourth separator may be positioned at the uppermost part of the stack cell according to one aspect of the present invention.

[0089] An electrode assembly according to one aspect of the present invention includes a fourth separator positioned at the top, wherein the fourth separator includes a separator substrate and a first porous coating layer comprising first inorganic particles and a first binder resin on one surface of the separator substrate. In this case, the first porous coating layer has a content of the first binder resin of 20 wt% or less.

[0090]

[0091] First porous coating layer

[0092] As described above, the electrode assembly (1) according to one aspect of the present invention includes a fourth separator (203) at the top, and the fourth separator (203) includes a separator substrate (2030) and a porous coating layer including inorganic particles and a binder resin on at least one surface of the separator substrate.

[0093] FIG. 3 shows a schematic diagram of the structure of a fourth separation membrane (203) according to one embodiment of the present invention.

[0094] In one embodiment of the present invention, the fourth separation membrane includes a first porous coating layer (2031) including inorganic particles and a binder resin at the top.

[0095] In one embodiment of the present invention, the fourth separation membrane may further include a second porous coating layer (2032) including inorganic particles and a binder resin on the back surface of the surface on which the first porous coating layer is formed.

[0096] In this specification, in order to distinguish the inorganic particles and binder resin included in each of the first porous coating layer and the second porous coating layer, for convenience, the inorganic particles and binder resin included in the first porous coating layer are referred to as the first inorganic particles and the first binder resin, respectively, and the inorganic particles and binder resin included in the second porous coating layer are referred to as the second inorganic particles and the second binder resin, respectively.

[0097] According to one embodiment of the present invention, the first porous coating layer includes first inorganic particles and a predetermined first binder resin for binding the first inorganic particles to improve the heat resistance of the separator.

[0098] At this time, it is preferable that the first binder resin is included in an amount that only provides bonding force between the first inorganic particles and does not exhibit surface adhesive force of the first porous coating layer.

[0099] Specifically, the content of the first binder resin in the first porous coating layer may be 20 wt% or less based on the total weight of the first porous coating layer.

[0100] For example, the content of the first binder resin may be 20 wt% or less, 15 wt% or less, 10 wt% or less, or 5 wt% or less, based on the total weight of the first porous coating layer. Specifically, the content of the first binder resin may be 0.01 to 20 wt%, 0.1 to 20 wt%, 0.5 to 15 wt%, 1 to 10 wt%, 1 to 8 wt%, 3 to 6 wt%, 3 to 5 wt%, 1 to 5 wt%, 1 to 3 wt%, or 1 to 2 wt%, based on the total weight of the first porous coating layer, but the present invention is not limited thereto.

[0101] In one embodiment of the present invention, the surface adhesive force of the first porous coating layer may exhibit, for example, 1 gf / 15 mm or less. Specifically, the surface adhesive force of the first porous coating layer may exhibit 1.0 gf / 15 mm or less. Since the surface adhesive force of the first porous coating layer exhibits a level of 1 gf / 15 mm or less, even when a plurality of stack cells to which the first porous coating layer is applied are stacked and transported, there is an advantage in that damage to the separator can be minimized because friction caused by vibration or the like is reduced, but the present invention is not limited thereto.

[0102] In this specification, the surface adhesion of the first porous coating layer can be measured, for example, by the following method. The surface adhesion can be measured by measuring the force when the separator and the electrode are peeled off when the side of the separator having the first porous coating layer is attached to the electrode and then pulled with a constant force. For example, the side of the separator having the first porous coating layer is sampled with a width of 15 mm and overlapped with the electrode, and then pressurized under the conditions of 60°C, 6.5 MPa, and 1 s to produce a sample. Next, the peel strength between the separator and the electrode is measured using a UTM device (Instron) at the conditions of 180° and 300 mm / min.

[0103] In one embodiment of the present invention, the surface adhesive strength of the first porous coating layer may also be referred to as 'electrode adhesive strength' considering the above measurement method.

[0104] In one embodiment of the present invention, when measuring the adhesive force between the separator and the electrode, the electrode may be a positive electrode. The composition of the positive electrode is not particularly limited, but for example, the measurement may be performed using a positive electrode manufactured with the following composition. NCMA (Li[Ni)) as a positive electrode active material in NMP as a solvent. 0.86 Co 0.06 Mn 0.07 Al 0.01 ]O2), PVDF as a binder polymer, and CNT as a conductive material are mixed in a weight ratio of 97:1:2 to prepare a composition for forming a positive electrode. The composition for forming a positive electrode is applied to one surface of an aluminum current collector and dried to prepare a positive electrode. The loading amount of the positive electrode is 4.5 mAh / cm 2 It is manufactured to become.

[0105] In another embodiment of the present invention, when measuring the adhesive force between the separator and the electrode, the electrode may be a negative electrode. The composition of the negative electrode is not particularly limited, but, for example, the measurement may be performed using a negative electrode manufactured with the following composition. A composition for forming a negative electrode is prepared by mixing Si particles (100% Si) as a negative electrode active material, SBR as a binder polymer, and CNT as a conductive material in a weight ratio of 80:10:10 in distilled water as a solvent. The composition for forming a negative electrode is applied to one surface of a copper current collector and dried to prepare a negative electrode. The loading amount of the negative electrode is 8.5 mAh / cm 2 It is manufactured to become.

[0106] According to one aspect of the present invention, the first porous coating layer is intended to implement low adhesive force at the top of the electrode assembly, and it may be preferable that the first porous coating layer be formed on the back surface of the surface where the fourth separator contacts the third electrode. For example, the second electrode laminate may have a structure of third separator / third electrode / ... / separator substrate of the fourth separator / first porous coating layer of the fourth separator. Here, ' / ... / ' between the third electrode and the separator substrate of the fourth separator means that the third electrode and the separator substrate of the fourth separator may be in direct contact with each other, and an adhesive binder and / or a second porous coating layer may be further included as described below, and the present invention is not limited thereto.

[0107] In one embodiment of the present invention, as long as the content of the binder resin in the first porous coating layer satisfies the above-described range, there is no particular limitation, but the first inorganic particles and the first binder resin in the first porous coating layer may be included in a weight ratio of, for example, 99:1 to 80:20. Specifically, the first inorganic particles and the first binder resin in the first porous coating layer may be included in a ratio of 99:1 to 80:20, 95:5 to 80:20, 95:5 to 80:20, 95:5 to 90:10, but the present invention is not limited thereto. The first porous coating layer may have a structural feature of a porous layer having a plurality of micropores therein, and having a structure in which these micropores are connected to each other, and through which gas or liquid can pass from one side to the other side.

[0108] In one embodiment of the present invention, the first inorganic particle can be used without particular limitation as long as it is electrochemically stable. That is, the inorganic particle that can be used in the present invention is not particularly limited as long as it does not undergo oxidation and / or reduction reactions in the operating voltage range of the applied electrochemical device (e.g., 0 to 5 V based on Li / Li+). Non-limiting examples of such inorganic particles include BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT, 0 <x<1, 0<y<1), Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3(PMN-PT), hafnia (HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, SiO2, Y2O3, Al2O3, SiC and TiO2, and one or more of these may be included.

[0109] In one embodiment of the present invention, the average particle diameter (D) of the inorganic particles 50 ) may be, for example, 100 nm or more. Specifically, the average particle diameter (D) of the inorganic particles 50 ) may be 100 nm to 1 ㎛, or 100 nm to 500 nm. When the average particle diameter of the inorganic particles is within the above-described range, it may exhibit a beneficial effect in terms of suppressing an increase in resistance of the separation membrane, but the present invention is not limited thereto.

[0110] The particle size of the above-mentioned inorganic particles can be measured by a known particle size measuring method, for example, it can be measured using a particle size analyzer (PSA, Particle Size Analyzer) of Melbourne Co. In addition, the average particle size (D 50 ) refers to the particle size at the 50% point of the cumulative distribution of the number of particles according to particle size, and may be measured using a known laser diffraction method. At this time, the laser diffraction particle size measuring device may be, for example, Microtrac S3500 from Microtrac Corporation.

[0111] In one embodiment of the present invention, the first binder resin may be used without particular limitation as long as it exhibits the above-described characteristics. However, for example, the first binder resin may include an aqueous binder that exhibits binding force between inorganic particles even when used in small amounts and improves the dispersibility of the inorganic particles, thereby forming a porous structure. Specifically, the first binder resin may include a non-fluorinated resin.

[0112] In one embodiment of the present invention, the first binder resin may include an acrylic binder as a non-fluorinated resin. The acrylic binder may include, for example, polyacrylic acid (PA), polyacrylonitrile (PAN), polyacrylamide (PAA), a (meth)acrylic polymer, or a mixture of two or more thereof, but the present invention is not limited thereto. The (meth)acrylic polymer refers to a polymer that includes a (meth)acrylic acid ester as a monomer. Such monomers may include, for example, 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 (meth)acrylate, n-oxyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, lauryl (meth)acrylate, tetradecyl (meth)acrylate or mixtures of two or more thereof, but the present invention is not limited thereto.

[0113]

[0114] adhesive binder

[0115] In one embodiment of the present invention, as described above, the first porous coating layer of the fourth separator is located at the uppermost part of the electrode assembly that is not attached to the electrode. Specifically, the first porous coating layer may be formed on the back surface of the surface of the fourth separator that contacts the third electrode.

[0116] In one embodiment of the present invention, it may be desirable for the surface of the fourth separator in contact with the third electrode to have a predetermined adhesive strength. For example, the interface between the third electrode and the fourth separator may include an adhesive binder.

[0117] FIG. 4 is a schematic diagram of an electrode assembly according to one embodiment of the present invention. Referring to FIG. 4, in one embodiment of the present invention, at least one of the interfaces between the first separator and the first electrode, the interface between the first electrode and the second separator, the interface between the second separator and the second electrode, the interface between the second electrode and the third separator, the interface between the third separator and the third electrode, and the interface between the third electrode and the fourth separator may include one or more adhesive binders (501).

[0118] In one embodiment of the present invention, it may be preferable that the adhesive strength between the electrode and the separator, which are in contact with each other through an interface including at least one adhesive binder, be, for example, 5 gf / 15 mm or more. Specifically, the adhesive force between the electrode and the separator may be 10 gf / 15 mm or more at at least one of the interface between the first separator and the first electrode, the interface between the first electrode and the second separator, the interface between the second separator and the second electrode, the interface between the second electrode and the third separator, the interface between the third separator and the third electrode, and the interface between the third electrode and the fourth separator, and specifically, 10 gf / 15 mm to 80 gf / 15 mm, 10 gf / 15 mm to 75 gf / 15 mm, 15 gf / 15 mm to 70 gf / 15 mm, 15 gf / 15 mm to 65 gf / 15 mm, 20 gf / 15 mm to 60 gf / 15 mm, 25 gf / 15 mm to 55 gf / 15 mm, 30 gf / 15 mm to It may be 50 gf / 15 mm or 15 gf / 15 mm to 30 gf / 15 mm, but the present invention is not limited thereto. When the adhesive force between the electrode and the separator at the interface is within the above-described range, it may have a beneficial effect in terms of improving the short-circuit stability between the electrodes and lowering the total resistance of the electrode assembly, but the present invention is not limited thereto.

[0119] In this specification, the adhesive strength between the electrode and the separator at the interface can be measured by sampling a sample with an electrode / adhesive binder / separator attached to a width of 15 mm, and using a UTM device (Instron) to pull it at 180°, 300 mm / min, and measuring the force intensity when the electrode and the separator are separated.

[0120] In one embodiment of the present invention, when measuring the adhesive strength between the electrode and the separator, the electrode may be an anode or a cathode. The composition of the anode and the cathode may refer to the method for measuring the surface adhesive strength of the first porous coating layer described above.

[0121] In one embodiment of the present invention, any adhesive binder capable of imparting adhesive strength between the electrode and the separator may be used without particular limitation. For example, the adhesive binder may include a fluorinated binder.

[0122] In one embodiment of the present invention, the fluorine-based binder is not particularly limited as long as it contains at least one fluorine (F) atom within the binder structure. For example, the fluorine-based binder may include, for example, a PVDF-based binder.

[0123] In one embodiment of the present invention, the PVDF-based binder may include at least one of a homopolymer of vinylidene fluoride (i.e., polyvinylidene fluoride), a copolymer of a monomer copolymerizable with vinylidene fluoride, and a mixture thereof. The monomer copolymerizable with vinylidene fluoride may be, for example, a fluorinated monomer and / or a chlorinated monomer. 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 more than one of these may be included.

[0124] In one embodiment of the present invention, the PVDF-based binder may include at least one selected from, for example, polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyvinylidene fluoride-chlorofluoroethylene (PVDF-CTFE), polyvinylidene fluoride-tetrafluoroethylene (PVdF-TFE), and polyvinylidene fluoride-trifluoroethylene (PVdF-TrFE).

[0125] In one embodiment of the present invention, the one or more adhesive binders included in the at least one interface may include, for example, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). In this case, the substitution content of HFP in the PVDF-HFP may include, for example, 3 mol% to 20 mol%, specifically 5 mol% to 15 mol%, based on the total mole number of PVDF-HFP, but the present invention is not limited thereto.

[0126] In the present specification, when a copolymer of two or more monomers is included as the PVDF-based binder, for example, when PVDF-HFP is included, the substitution content of monomers other than vinylidene fluoride in the copolymer can be measured using a conventional analysis method. For example, the substituent content can be measured using a known method for analyzing the substituent content using C-NMR, but the present invention is not limited thereto.

[0127] In another embodiment of the present invention, the interface between the first separator and the first electrode, the interface between the first electrode and the second separator, the interface between the second separator and the second electrode, the interface between the second electrode and the third separator, the interface between the third separator and the third electrode, and the interface between the third electrode and the fourth separator may include one or more PVDF-based binders. For example, the interface between the first separator and the first electrode, the interface between the first electrode and the second separator, the interface between the second separator and the second electrode, the interface between the second electrode and the third separator, the interface between the third separator and the third electrode, and the interface between the third electrode and the fourth separator may include PVDF-HFP, but the present invention is not limited thereto.

[0128] In one embodiment of the present invention, when at least one adhesive binder is included in the above-described at least one interface, the at least one adhesive binder may be included by coating the adhesive binder on the surface of an adjacent separator and then laminating the electrode on the adhesive binder coating layer. Alternatively, the at least one adhesive binder may be included by coating the adhesive binder on the surface of an adjacent electrode and then laminating the separator on the adhesive binder coating layer. Alternatively, the at least one adhesive binder may be included by coating the adhesive binder on both the surface of an adjacent electrode and the surface of a separator and then laminating the electrode and the separator so that their respective adhesive binder coating layers are in contact. The method for coating the adhesive binder on the surface of the electrode and / or the separator is not particularly limited.

[0129] In one embodiment of the present invention, the method of coating one or more adhesive binders on the surface of the electrode and / or separator may use a conventional coating method known in the art, and various methods such as dip coating, die coating, roll coating, comma coating, or a mixture thereof may be used. In addition, the drying may be applied without any particular limitation to a conventional drying method such as natural drying or air drying.

[0130] In one embodiment of the present invention, in order to coat one or more adhesive binders on the surface of the electrode and / or separator, the adhesive binder may be dispersed or dissolved in an appropriate solvent to prepare an adhesive binder coating solution. Non-limiting examples of the solvent include one or a mixture of two or more selected from the group consisting of water, acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone (NMP), and cyclohexane, but the present invention is not limited thereto.

[0131] In one embodiment of the present invention, the adhesive binder described above may be derived from a second porous coating layer formed on the separator adjacent to the interfaces.

[0132]

[0133] Second porous coating layer

[0134] In one embodiment of the present invention, in addition to the upper surface on which the first porous coating layer of the fourth separator located at the top of the electrode assembly is formed, at least one surface of the first separator, the second separator, and the third separator in the electrode assembly, and the back surface of the surface on which the first porous coating layer of the fourth separator is formed may include a second porous coating layer including inorganic particles and a binder resin.

[0135] FIG. 5 is a schematic diagram of a second separator according to an embodiment of the present invention. Referring to FIG. 5, the second separator (103) may include a separator substrate (1030) and a second porous coating layer (1032) on at least one surface of the separator substrate. Although not shown, the first separator and the third separator may also include a separator substrate and a second porous coating layer on at least one surface of the separator substrate.

[0136] According to one embodiment of the present invention, the second porous coating layer may be included to exhibit adhesion to an adjacent electrode, and may preferably have a different composition from the first porous coating layer.

[0137] In one embodiment of the present invention, the first porous coating layer and the second porous coating layer may have different compositions. Here, "different compositions" means that at least one of the types of inorganic particles and binder resin included in the first porous coating layer and the second porous coating layer is different from each other, or even if the types of inorganic particles and binder resin are the same, the weight ratios therebetween are different from each other.

[0138] In this specification, the inorganic particles and binder resin included in the second porous coating layer may be referred to as second inorganic particles and second binder resin, respectively, to distinguish them from the inorganic particles and binder resin in the first porous coating layer described above.

[0139] In one embodiment of the present invention, the type of the second inorganic particle is the same as that described above with respect to the first inorganic particle.

[0140] In one embodiment of the present invention, the second binder resin may include a non-fluorinated resin, a fluorinated resin, or a mixture thereof.

[0141] In another embodiment of the present invention, the second binder resin may include a non-fluorinated resin. The non-fluorinated resin may be as described for the first binder resin.

[0142] In another embodiment of the present invention, the second binder resin may include a fluorinated resin. The fluorinated resin may be as described above for the adhesive binder.

[0143] In one embodiment of the present invention, the second porous coating layer is formed on at least one surface of at least one surface of the first separator, the second separator, and the third separator, and the back surface of the surface on which the first porous coating layer of the fourth separator is formed, and it may be preferable to exhibit adhesiveness with an adjacent electrode.

[0144] To this end, in one embodiment of the present invention, it may be preferable that the second binder resin includes a fluorine-based resin and is included in an amount such that the surface adhesive strength of the second porous coating layer is 5 gf / 15 mm or more. Here, the surface adhesive strength of the second porous coating layer is based on what has been described with respect to the surface adhesive strength of the first porous coating layer.

[0145] In one embodiment of the present invention, the second porous coating layer may be formed according to a conventional method for forming a porous coating layer including inorganic particles and binder resin on the surface of a membrane substrate, and there is no particular limitation on the forming method.

[0146] According to one embodiment of the present invention, the second porous coating layer may be formed by a humidified-bed separation (SRS) method. Specifically, the second porous coating layer may be formed by applying a slurry including second inorganic particles and a second binder resin onto at least one surface of a membrane substrate and then drying under humidified conditions. According to this method, when the slurry is dried, the second inorganic particles may be positioned at the lower portion adjacent to the surface of the membrane substrate, whereas the second binder resin may have the characteristic of drying while moving upwardly away from the surface of the membrane substrate. Accordingly, a concentration gradient of the second binder resin may be formed in the second porous coating layer such that the concentration of the second binder resin is lower the closer to the membrane substrate, and the concentration of the second binder resin is higher the closer to the surface of the second porous coating layer.

[0147] According to one embodiment of the present invention, in the case where the adhesive binder is a second binder resin included in a second porous coating layer formed by a wet phase separation method of an adjacent separator at at least one interface among the interface between the first separator and the first electrode, the interface between the first electrode and the second separator, the interface between the second separator and the second electrode, the interface between the second electrode and the third separator, the interface between the third separator and the third electrode, and the interface between the third electrode and the fourth separator, the adhesive binder included in the at least one interface may have a structure in which a concentration gradient is formed from the surface of the adjacent electrode to the surface of the adjacent separator so that the concentration of the adhesive binder becomes lower the closer to the adjacent separator. However, the structure and manufacturing method of the electrode assembly are not limited thereto.

[0148] In one embodiment of the present invention, when the second porous coating layer is formed by the above-described humidification separation method, the surface adhesive force of the second porous coating layer may be 30 gf / 15 mm or more. For example, the surface adhesive force of the second porous coating layer may be 30 gf / 15 mm to 80 gf / 15 mm, 30 gf / 15 mm to 75 gf / 15 mm, 35 gf / 15 mm to 70 gf / 15 mm, 40 gf / 15 mm to 65 gf / 15 mm, or 50 gf / 15 mm to 60 gf / 15 mm, but the present invention is not limited thereto.

[0149] In another embodiment of the present invention, the second porous coating layer may be formed to have a multilayer structure of a first layer (inorganic particle layer) including second inorganic particles on the surface of the separator substrate, and a second layer (binder layer) including a second binder resin on the first layer.

[0150] In one embodiment of the present invention, the second porous coating layer having a multilayer structure may be formed by applying and drying a slurry containing second inorganic particles and a slurry containing a second binder resin to the surface of the separator substrate, respectively. For example, the second porous coating layer may be formed by applying a slurry containing second inorganic particles and a third binder resin to the surface of the separator substrate, and then applying and drying a slurry containing the second binder resin thereon. The third binder resin may include a non-fluorinated resin, a fluorinated resin, or a mixture thereof. When the third binder resin uses a non-fluorinated resin, it may be more preferable in terms of providing a bonding force between the second inorganic particles without increasing the overall resistance of the electrode assembly, but the present invention is not limited thereto. The types of the non-fluorinated resin and the fluorinated resin are those described above.

[0151] In one embodiment of the present invention, the second porous coating layer of the multilayer structure has a structure including a second binder resin in the second layer (binder layer). At this time, unlike the above-described humidification separation, it is preferable that the second binder resin does not form a concentration gradient within the second layer.

[0152] In one embodiment of the present invention, in the case where the second binder resin is included in the second porous coating layer having a multi-layer structure of the separator, the adhesive binder may be included so as not to have a concentration gradient in the thickness direction at at least one interface among the interface between the first separator and the first electrode, the interface between the first electrode and the second separator, the interface between the second separator and the second electrode, the interface between the second electrode and the third separator, the interface between the third separator and the third electrode, and the interface between the third electrode and the fourth separator. However, the structure and manufacturing method of the electrode assembly are not limited thereto.

[0153] In one embodiment of the present invention, when the second porous coating layer is formed to have the multilayer structure described above, the surface adhesive force of the second porous coating layer may be 10 gf / 15 mm or more. For example, the surface adhesive force of the second porous coating layer may be 10 gf / 15 mm to 50 gf / 15 mm, 15 gf / 15 mm to 40 gf / 15 mm, 15 gf / 15 mm to 30 gf / 15 mm, 15 gf / 15 mm to 25 gf / 15 mm, or 15 gf / 15 mm to 20 gf / 15 mm, but the present invention is not limited thereto.

[0154] In one embodiment of the present invention, the surface adhesive force of the second porous coating layer can be measured by referring to the method for measuring the surface adhesive force of the first porous coating layer.

[0155] Accordingly, in one embodiment of the present invention, the surface adhesive strength of the second porous coating layer may also be referred to as 'electrode adhesive strength' considering the above measurement method.

[0156] In one embodiment of the present invention, the second binder resin in the second porous coating layer may represent 10 wt% or more based on the total weight of the second porous coating layer. Specifically, the content of the second binder resin may be greater than 10 wt%, specifically greater than 20 wt%, or greater than 20 wt% based on the total weight of the second porous coating layer. For example, the content of the second binder resin may be 10 to 95 wt%, 15 to 95 wt%, 20 to 95 wt%, 30 to 90 wt%, 40 to 80 wt%, 50 to 70 wt%, 20 to 80 wt%, 20 to 60 wt%, or 20 to 45 wt% based on the total weight of the second porous coating layer, but the present invention is not limited thereto.

[0157] In one embodiment of the present invention, the second porous coating layer may be composed only of a second binder resin and second inorganic particles, and accordingly, the content of the second inorganic particles may be the remainder other than the second binder resin based on the total weight of the second porous coating layer.

[0158] In another embodiment of the present invention, the second porous coating layer may further include other additives such as a dispersant in addition to the second binder resin and the second inorganic particles, but the present invention is not limited thereto.

[0159] In one embodiment of the present invention, in one embodiment of the present invention, as long as the content of the binder resin in the second porous coating layer satisfies the above-described range, there is no particular limitation, but the second binder resin and the second inorganic particles in the second porous coating layer may be included in a weight ratio of, for example, 99:1 to 10:90. Specifically, the second binder resin and the second inorganic particles in the second porous coating layer may be included in a ratio of 99:1 to 20:80, 95:5 to 20:80, 95:5 to 30:70, 90:10 to 40:60, 90:10 to 50:50, 85:15 to 55:45, 85:15 to 60:40, 80:20 to 70:30 or 80:20 to 75:25, or 50:50 to 20:80, 40:60 to 20:80 or 20:70 to 20:80, but the present invention is not limited thereto.

[0160]

[0161] As described above, according to one embodiment of the present invention, the electrode assembly includes a second porous coating layer included in at least one of the first separator, the second separator, and the third separator, and a first porous coating layer formed on an upper surface in the thickness direction of the fourth separator. According to one embodiment of the present invention, the first binder resin included in the first porous coating layer may include a non-fluorinated binder, and the second binder resin included in the second porous coating layer may include a fluorinated binder.

[0162] In one embodiment of the present invention, the first binder resin, the adhesive binder, and the second binder resin can be confirmed to contain a non-fluorine binder or a fluorine binder by confirming the presence or absence of fluorine (F) element through component analysis, but the confirmation method is not limited thereto.

[0163] In one embodiment of the present invention, the surface adhesive force of the first porous coating layer may be 1 gf / 15 mm or less, and the surface adhesive force of the second porous coating layer may be 5 gf / 15 mm or more, but the present invention is not limited thereto.

[0164] In one embodiment of the present invention, each of the first separator, the second separator, the third separator, and the fourth separator includes a separator substrate. The separator substrate may be any substrate that can be used as a separator substrate for an electrochemical device, without limitation. For example, the separator substrate may be a polyolefin-based substrate, or may be a substrate including at least one polymer resin other than polyolefin, such as polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalene. In addition, the separator substrate may be, but is not particularly limited to, a non-woven fabric, a porous polymer film, or a laminate of two or more thereof.

[0165]

[0166] According to another aspect of the present invention, a method for manufacturing the electrode assembly can be provided.

[0167] A method for manufacturing an electrode assembly according to another aspect of the present invention may include a step of sequentially stacking a first separator, a first electrode, a second separator, and a second electrode in the thickness direction to prepare a first electrode assembly, a step of sequentially stacking a third separator, a third electrode, and a fourth separator in the thickness direction to prepare a second electrode stack, and a step of sequentially stacking one or more of the first electrode assemblies and stacking the second electrode assembly on the top. At this time, as described above, the fourth separator includes a separator substrate, and a first porous coating layer including first inorganic particles and a first binder resin on an upper surface of the separator substrate, and it is preferable that the content of the first binder resin in the first porous coating layer is 20 wt% or less.

[0168] In one embodiment of the present invention, a step of preparing the first separator, the second separator, and the third separator may be further included. At this time, the first separator, the second separator, and the third separator each include a separator substrate, and a second porous coating layer formed on at least one surface of the separator substrate, and the composition of the second porous coating layer may be different from the composition of the first porous coating layer.

[0169] In one embodiment of the present invention, the method may further include forming a second porous coating layer on at least one surface of the first separator, the second separator, and the third separator, and on the back surface of the surface of the fourth separator on which the first porous coating layer is formed, respectively. Each of the second porous coating layers may be formed using the same method, or may be formed using different methods. For example, a second porous coating layer may be formed on both surfaces of the first separator so as to have a concentration gradient of the second binder resin, and a second porous coating layer having a multilayer structure without a concentration gradient of the second binder resin may be formed on both surfaces of the second separator. Alternatively, a second porous coating layer may be formed on one surface of the first separator so as to have a concentration gradient of the second binder resin, and a second porous coating layer having a multilayer structure without a concentration gradient of the second binder resin may be formed on the other surface.

[0170]

[0171] According to another aspect of the present invention, an electrochemical device including the electrode assembly can be provided.

[0172] The above electrochemical device can be manufactured by including a process of loading the electrode assembly into a suitable case and injecting an electrolyte, but the present invention is not limited thereto.

[0173]

[0174] Hereinafter, the present invention will be described in more detail through examples, but the following examples are intended to illustrate the present invention, and the scope of the present invention is not limited to these examples.

[0175] [Manufacturing of electrode assembly]

[0176] Example 1

[0177] After sequentially stacking 19 first electrode laminates, one second electrode laminate was stacked on top, and then taped along the long side in the thickness direction to manufacture a stack cell.

[0178] The first electrode stack was manufactured to have a structure of [first separator / cathode / second separator / anode] stacked in the thickness direction, and the second electrode stack was manufactured to have a structure of [third separator / cathode / fourth separator] stacked in the thickness direction. The stack cell was assembled so that the fourth separator was positioned at the top.

[0179] The above first, second, and third separators each used a porous coating layer formed on both sides of a polyethylene separator substrate using a humidified separation method. Specifically, a porous coating layer was formed by applying a slurry containing a PVDF-HFP binder (Mw 500,000 g / mol, HFP 15 wt%) and inorganic particles (Al2O3) mixed in a solvent at a weight ratio of 20:80, and then drying under humidified conditions.

[0180] The fourth separator formed a first porous coating layer on one surface and a second porous coating layer on the other surface. In order to form the first porous coating layer, a slurry containing a PAA (MW 350,000 g / mol) binder and inorganic particles (Al2O3) mixed in a weight ratio of 5:95 in an aqueous solvent was applied to one surface of a polyethylene separator substrate and dried. In order to form the second porous coating layer, a slurry of inorganic particles (Al2O3) dispersed in a solvent was applied to the other surface of the polyethylene separator substrate and dried, and then a slurry of PVDF-HFP binder (Mw 500,000 g / mol, HFP 15 wt%) dispersed in a solvent (binder solid content 15 wt%) was applied thereon and dried. Thus, the second porous coating layer was formed to have a multilayer structure of an inorganic particle layer / binder layer in the order adjacent to the separator substrate, and the weight ratio of the second binder resin:second inorganic particles was 20:80. In this way, the first porous coating layer was formed on one side of the fourth separator, and the second porous coating layer having a multilayer structure of an inorganic particle layer / binder layer was formed on the other side.

[0181] When assembling the second electrode laminate, the cathode and the second porous coating layer of the fourth separator, i.e., the porous coating layer of the multilayer structure, were assembled so that they were in contact.

[0182]

[0183] Comparative Example 1

[0184] An electrode assembly was manufactured using the same method as Example 1, except that the first separator, the second separator, the third separator, and the fourth separator all included porous coating layers formed on both sides using a humidified separation method.

[0185] Specifically, the porous coating layer was formed by applying a slurry containing a PVDF-HFP binder (Mw 500,000 g / mol, HFP 15 wt%) and inorganic particles (Al2O3) mixed in a solvent at a weight ratio of 20:80 to both sides of a polyethylene separator substrate, and then drying under humidified conditions.

[0186]

[0187] The surface adhesive strength of the porous coating layer formed on the separator manufactured in Example 1 and Comparative Example 1 was measured as follows.

[0188] A sample was prepared by attaching the surface on which the porous coating layer was formed so that it faces the prepared anode and applying pressure under the conditions of 60°C, 6.5 MPa, and 1 s. Next, the peel strength between the separator and the electrode was measured using a UTM device (Instron) under the conditions of 180° and 300 mm / min.

[0189] The above positive electrode is composed of NCMA (Li[Ni) as a positive electrode active material and NMP as a solvent. 0.86 Co 0.06 Mn 0.07 Al 0.01]O2), PVDF as a binder polymer, and CNT as a conductive material were mixed in a weight ratio of 97:1:2 to prepare a composition for forming a positive electrode, and the composition for forming a positive electrode was applied to one side of an aluminum current collector and dried to prepare the composition. The loading amount of the positive electrode was 4.5 mAh / cm 2 It was manufactured to be , and before attachment to the separator, it was sampled with a width of 15 mm and attached so as to face the porous coating layer of the separator.

[0190] Adhesion of electrodes subject to measurement (gf / 15 mm) Example 1 First separator, second separator, third separator (average) 20 Fourth separator (first porous coating layer) 0.3 Fourth separator (second porous coating layer) 16 Comparative example 1 First separator, second separator, third separator, fourth separator 21

[0191]

[0192] [Circular Logistics Test]

[0193] Each stack cell manufactured as described above was stacked 25 times on a tray and then transported on a conveyor belt. The conveyor belt was configured in a circular configuration and, to simulate various situations, was stopped every 5 minutes during transport at a speed of 20 m / min to apply vibration to the tray and the stacked stack cells. This process was performed for 12 hours, and the stack cells were removed from the tray and observed for their appearance.

[0194] The stack cells of Example 1 had no problems even after a 12-hour test, but it was confirmed that the stack cells of Comparative Example 1 had scratches on the surface between the stack cells, as shown in Fig. 1, which could cause poor battery performance.

[0195] Although the present invention has been described with reference to embodiments thereof, those skilled in the art will be able to make various applications and modifications within the scope of the present invention based on the above contents.

[0196] [Explanation of symbols]

[0197] 1: Electrode assembly

[0198] 10: First electrode stack

[0199] 101: First membrane

[0200] 102: First electrode

[0201] 103: Second membrane

[0202] 104: Second electrode

[0203] 20: Second electrode stack

[0204] 201: Third membrane

[0205] 202: Third electrode

[0206] 203: 4th membrane

[0207] 2030: Membrane Materials

[0208] 2031: First porous coating layer

[0209] 2032: Second porous coating layer

[0210] 501: Adhesive binder

[0211] 1030: Membrane substrate

[0212] 1032: Second porous coating layer

Claims

1. It comprises at least one first electrode laminate including a first separator, a first electrode, a second separator, and a second electrode sequentially laminated in the thickness direction, A second electrode laminate comprising a third separator, a third electrode, and a fourth separator sequentially laminated in the thickness direction, The second electrode stack has a structure in which the third separator is stacked on the top of the one or more first electrode stacks so that it comes into contact with the second electrode stack, An electrode assembly, wherein the fourth separator comprises a separator substrate and a first porous coating layer comprising first inorganic particles and a first binder resin on one surface of the separator substrate, wherein the content of the first binder resin in the first porous coating layer is 20 wt% or less.

2. In claim 1, Two or more of the above first electrode laminates are continuously laminated in the thickness direction, An electrode assembly having a structure in which the second electrode laminate is laminated on the top of the first electrode laminate.

3. In claim 1, An electrode assembly, wherein the content of the first binder resin in the first porous coating layer is 5 wt% or less.

4. In claim 1, An electrode assembly, wherein the first porous coating layer is formed on the back surface of the surface where the fourth separator comes into contact with the third electrode.

5. In claim 1, The interface between the first separator and the first electrode, The interface between the first electrode and the second separator, The interface between the second separator and the second electrode, The interface between the second electrode and the third separator, The interface between the third separator and the third electrode, and An electrode assembly, wherein at least one interface between the third electrode and the fourth separator includes one or more types of adhesive binders.

6. In claim 5, An electrode assembly, wherein a concentration gradient is formed from the surface of the adjacent electrode to the surface of the adjacent separator, such that the concentration of the adhesive binder included in at least one interface becomes lower the closer it is to the adjacent separator.

7. In claim 5, An electrode assembly having no concentration gradient of the adhesive binder in the thickness direction at at least one interface.

8. In claim 5, An electrode assembly, wherein the adhesive binder comprises a fluorine-based binder.

9. In claim 1, The first separator, the second separator, and the third separator each independently include a separator substrate, and a second porous coating layer formed on at least one surface of the separator substrate, The second porous coating layer includes second inorganic particles and a second binder resin, The above first binder resin includes a non-fluorine-based binder, An electrode assembly, wherein the second binder resin includes a fluorine-based binder.

10. In claim 9, The second porous coating layer has a content gradient of the second binder resin in which the content of the second binder resin increases from the lower part adjacent to the separator substrate to the upper part, which is the outermost part of the separator. An electrode assembly, wherein the first porous coating layer of the fourth separator does not have a concentration gradient of the first binder resin.

11. In claim 9, An electrode assembly having a multilayer structure, wherein the second porous coating layer comprises an inorganic particle layer including second inorganic particles formed on the surface of an adjacent separator substrate, and a binder layer including a second binder resin formed on the surface of the inorganic particle layer.

12. In claim 1, The fourth separator is formed on a surface in contact with the third electrode and further includes a second porous coating layer including second inorganic particles and a second binder resin. The surface adhesion of the first porous coating layer is 1 gf / 15 mm or less, An electrode assembly, wherein the surface adhesion of the second porous coating layer is 5 gf / 15 mm or more.

13. A step of preparing a first electrode assembly by sequentially stacking a first separator, a first electrode, a second separator, and a second electrode in the thickness direction. A step of preparing a second electrode laminate by sequentially laminating a third separator, a third electrode, and a fourth separator in the thickness direction, and A step of sequentially stacking one or more of the first electrode assemblies and stacking a second electrode assembly on the top, A method for manufacturing an electrode assembly, wherein the fourth separator comprises a separator substrate and a first porous coating layer including first inorganic particles and a first binder resin on the upper surface of the separator substrate, and the content of the first binder resin in the first porous coating layer is 20 wt% or less.

14. In claim 13, It further includes a step of preparing the first separator, the second separator, and the third separator, The first separator, the second separator, and the third separator each include a separator substrate and a second porous coating layer formed on at least one surface of the separator substrate, A method for manufacturing an electrode assembly, wherein the composition of the second porous coating layer is different from the composition of the first porous coating layer.

15. An electrochemical device comprising an electrode assembly according to any one of claims 1 to 12.

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