SUBSTRATO SEPARADOR, MÉTODO PARA FABRICAR O MESMO E SEPARADOR INCLUINDO O MESMO

Abstract

The present invention relates to a separator substrate, a separator, an electrode assembly, and an electrochemical device. According to one embodiment of the present invention, the separator substrate has a surface roughness value (Sa) within a predetermined range. Accordingly, the adhesive strength of a separator using the separator substrate is well maintained, and the resistance characteristics of the separator are improved by reducing the amount of slurry impregnated during the formation of a porous coating layer.

Description

1 / 27 “SEPARATOR SUBSTRATE, METHOD FOR MANUFACTURING THE SAME AND SEPARATOR INCLUDING THE SAME” FIELD OF TECHNIQUE

[001] The present disclosure relates to a separating substrate, a method for manufacturing the same, and a separator that includes it. More particularly, the present disclosure relates to a separator with improved adhesion strength and electrical resistance characteristics, and to an electrode assembly and an electrochemical device that includes it.

[002] This application claims priority to Korean Patent Application No. 2023-0095298 filed on July 21, 2023 in the Republic of Korea, the disclosure of which is incorporated into the present invention by reference. BACKGROUND

[003] A secondary lithium battery is manufactured through a process of inserting an electrode assembly including a positive electrode / a separator / a negative electrode into a battery case, injecting an electrolyte solution, and sealing the battery case. The separator for use in the secondary lithium battery generally includes a porous polyolefin-based substrate, and to solve a short-circuit problem of the positive and negative electrodes due to thermal contraction behaviors of the porous polyolefin-based substrate, a separator with a coating layer formed from a mixture of inorganic particles and a binding polymer on the surface of the porous substrate has been developed to improve the mechanical and thermal resistance of the separator. For example, such a separator may include Safety Reinforced Separators (SRS) and Ceramic Coated Separators (CCS).

[004] Because the inorganic particles in the coating layer act as a spacer to maintain the physical shape of the separator, when the SRS or CCS is exposed to high temperature, it may be possible to suppress substrate shrinkage. Petition 870250084333, dated 09 / 18 / 2025, page 39 / 68 2 / 27 porous, thus preventing direct contact between the positive and negative electrodes. Consequently, the electrode assembly is manufactured by adhering the positive and negative electrodes to the separator with the porous coating layer on two surfaces between the positive and negative electrodes.

[005] However, resistance increases due to the impregnation of a fluid paste to form the porous coating layer on a portion of the porous polymeric substrate. Recently, there has been a growing demand for batteries with fast charging and high efficiency characteristics, and many studies have been conducted to reduce battery resistance. REVELATION Technical Problem

[006] The present disclosure aims to provide a separator capable of solving the problems described above and an electrode assembly and an electrochemical device that includes it.

[007] Specifically, the present disclosure aims to provide a separator substrate for reducing the resistance of a separator, one of the components of an electrochemical device, for example, a secondary lithium battery to reduce the battery resistance, a method for manufacturing the same, a separator using the same and an electrochemical device that includes it.

[008] In particular, the present disclosure aims to provide a separator substrate with improved surface characteristics to suppress the increase in separator resistance by reducing the degree of impregnation of a fluid paste to form the coating layer when forming the porous coating layer on the separator substrate and a method for its manufacture. Technical Solution

[009] To solve the problems described above, Petition 870250084333, dated 09 / 18 / 2025, p. 40 / 68 3 / 27

[010] according to an aspect of the present disclosure, a separating substrate of the following embodiments is provided.

[011] The separating substrate according to a first embodiment is a porous polymeric substrate with a surface roughness (Sa) of 30 nm to 80 nm on at least one surface.

[012] According to a second embodiment, in the first embodiment, the surface roughness (Sa) of the two surfaces of the porous polymeric substrate can be from 30 nm to 70 nm.

[013] In accordance with another aspect of the present disclosure, a separator is provided for the following modalities.

[014] The separator according to a third modality includes: the separating substrate according to the first embodiment or the second embodiment, and a porous coating layer present on at least one of the surfaces of the separating substrate with a surface roughness (Sa) of 30 nm to 80 nm, the porous coating layer including inorganic particles and a binding polymer.

[015] According to a fourth embodiment, in the third embodiment, an adhesion force between the separating substrate and the porous coating layer can be 30 gf / 15 mm or more.

[016] According to a fifth embodiment, in the third or fourth embodiment, the adhesion force between the separating substrate and the porous coating layer can be from 30 gf / 15 mm to 140 gf / 15 mm.

[017] According to a sixth embodiment, in any of the third to fifth embodiments, an electrical resistance of the separator can be 1 Ω or less. Petition 870250084333, dated 09 / 18 / 2025, p. 41 / 68 4 / 27

[018] According to a seventh embodiment, in any of the third to sixth embodiments, the electrical resistance of the separator may be 0.9 Ω or less.

[019] According to an eighth embodiment, in any of the third to seventh embodiments, an average particle size (D50) of inorganic particles can be 100 nm or more.

[020] According to another aspect of the present disclosure, a set of electrodes of the following types is provided.

[021] The electrode array according to a ninth modality includes: the separator according to any of the third to eighth modalities, and a positive electrode and a negative electrode, each present on each of the two surfaces of the separator.

[022] According to a tenth mode, in the ninth mode, the resistance of the electrode array can be 1 Ω or less.

[023] According to an eleventh mode, in the ninth or tenth mode, the resistance of the electrode array may be 0.9 Ω or less.

[024] According to another aspect of the present disclosure, an electrochemical device of the following embodiments is provided.

[025] The electrochemical device according to a twelfth embodiment includes: the electrode array according to the ninth to eleventh modalities and a case that houses the electrode array.

[026] According to another aspect of the present disclosure, a method is provided for manufacturing a separating substrate of the following embodiments.

[027] The method for manufacturing the separating substrate according to a Petition 870250084333, dated 09 / 18 / 2025, p. 42 / 68 5 / 27 thirteenth modality includes the following stages:

[028] S1) extrude a fluid polymer paste to obtain a polymer sheet; and

[029] S2) heat-set the resulting polymer sheet, in which the heat-setting in step S2 is carried out at a temperature between 119 °C and 132 °C. Advantageous Effects

[030] The separating substrate according to an embodiment of the present disclosure can reduce the degree of impregnation of the fluid paste to form a coating layer by forming the porous coating layer on the separating substrate through enhanced surface roughness Sa.

[031] Consequently, the separator that uses the same may have improved adhesion strength and resistance characteristics compared to the separator having the conventional porous coating layer to provide thermal resistance and adhesion.

[032] Consequently, the electrochemical device using the separator can have characteristics of improved thermal resistance, low electrical resistance and high efficiency. BEST WAY

[033] Next, the present revelation will be described in detail.

[034] The term include or comprise when used in this descriptive report, specifies the presence of established elements, but does not exclude the presence or addition of one or more other elements, unless the contrary appears in the context.

[035] In the descriptive report, A and / or B refers to A or B or both.

[036] The specific terms used in the following description are provided for convenience, but are not intended to limit the present disclosure. Additionally, Petition 870250084333, dated 09 / 18 / 2025, p. 43 / 68 6 / 27 Words indicating directions such as top, bottom, left, right, front, back, inside, and outside indicate a direction in the drawings to which reference is made, or a direction toward or away from the geometric center of the established devices, systems, and elements.

[037] According to one aspect of the present disclosure, a separating substrate with surface roughness Sa of 30 nm to 160 nm is provided on at least one surface as a porous polymeric substrate. Separating substrate and its manufacturing method

[038] According to one aspect of the present disclosure, a separating substrate with surface roughness Sa of 30 nm to 80 nm is provided on at least one surface as a porous polymeric substrate.

[039] To describe this, a feature of a method for manufacturing the separating substrate according to an embodiment of the present disclosure will first be described.

[040] The method for manufacturing the separating substrate according to one aspect of the present disclosure includes the steps of:

[041] S1) extrude a fluid polymer paste to obtain a polymer sheet; and

[042] S2) heat-set the resulting polymer sheet.

[043] In this example, according to an aspect of the present disclosure, the heat setting in step S2 is carried out at a temperature between 119 °C and 132 °C.

[044] In one embodiment of the present disclosure, heat setting can be performed to forcibly hold the polymer sheet to remove residual tension in the sheet, but the purpose of the present disclosure is not limited to this.

[045] Conventionally, when manufacturing the porous polymeric substrate as the separating substrate, the fluid polymeric paste was extruded to obtain the polymeric sheet, and the resulting polymeric sheet was heat-set at high temperature. The Petition 870250084333, dated 09 / 18 / 2025, page 44 / 68 7 / 27 inventors discovered that heat-setting the polymer sheet induces surface crystallization of the polymer sheet, causing the surface characteristics to change, and obtained the separator substrate with surface roughness Sa of 30 nm to 80 nm by heat-setting in the specific temperature range to induce surface crystallization of the separator substrate.

[046] In one embodiment of the present disclosure, the heat-setting in step S2 can be carried out at temperatures between 119 °C and 132 °C, and specifically between 120 °C and 131 °C or between 121 °C and 130 °C. When the heat-setting temperature is in the aforementioned range, the surface roughness Sa can be from 30 nm to 80 nm. Additionally, when the temperature is excessively high, the surface roughness of the separating substrate can increase, leading to increased separator strength, and when the temperature is excessively low, the low surface roughness of the separating substrate can cause low adhesion strength between the separating substrate and the porous coating layer, but the present disclosure is not limited to this.

[047] In one embodiment of the present disclosure, in the heat-setting process, heat can be applied while stretching monoaxially in the MD (machine direction) or TD (transverse direction), or while stretching biaxially in the MD and TD directions, but is not limited to this.

[048] The 'machine direction' as used in the present invention refers to a direction parallel to a direction in which the process [extrusion->forming->stretching...] occurs in the manufacturing process of the separator substrate. The machine direction can be identified through the fiber orientation in the polymer of the separator substrate, and is a direction parallel to the fiber orientation. Consequently, the 'transverse direction' refers to a direction perpendicular to the machine direction. The transverse direction can be a direction perpendicular to the fiber orientation in the polymer of the separator substrate. Petition 870250084333, dated 09 / 18 / 2025, page 45 / 68 8 / 27

[049] According to one embodiment of the present disclosure, the method for manufacturing the separating substrate may further include, after extrusion in step S1), steps S1-2) shaping the extruded product into a sheet, S1-3) stretching the formed sheet, and S1-4) extracting a diluent from the stretched sheet. In this case, step S2) may be performed to heat-set the sheet from which the diluent was extracted.

[050] First, the extrusion of step S1 will be described in detail.

[051] In one embodiment of the present disclosure, step S1) may include performing melt extrusion and processing a polymeric resin as a separator substrate feedstock to obtain the porous polymeric sheet.

[052] In one embodiment of the present disclosure, the polymer resin may include any type of resin used as the raw material for manufacturing the separator substrate without limitation. The polymer resin may include any type of resin as the raw material for manufacturing the separator substrate, for example, polyolefin, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene naphthalene, or a mixture thereof. Polyolefin resin is formed by polymerization of olefin, and refers to a polymer produced from an olefin commonly used in the separator substrate as a monomer.For example, polyolefin resin may include polyethylene; polypropylene; polybutylene; polypentene; polyhexene; polyoctene; a homopolymer of a monomer selected from ethylene, propylene, butene, pentene, 4-methylpentene, hexene, and octene; a copolymer of two or more of them; or a mixture thereof, but is not limited to these.

[053] In one embodiment of the present disclosure, the porous polymeric substrate can be a polyolefin substrate.

[054] In one embodiment of the present disclosure, the porous polymeric substrate can be a polyethylene substrate.

[055] In one embodiment of the present disclosure, the diluent commonly Petition 870250084333, dated 09 / 18 / 2025, pp. 46 / 68 9 / 27 used can be used to extrude the polymer resin fed into an extruder. The diluent may include liquid or solid paraffin oil, wax, and soybean oil, commonly used in separator manufacturing.

[056] In one embodiment of the present disclosure, for melting and extrusion, the commonly used single or twin screw extruder may be used, but is not limited to it. In one embodiment of the present disclosure, a mixture of the diluent and the polymer resin may be fed into the extruder, followed by melting and mixing of the polymer resin at high temperature to obtain a molten composition.

[057] Subsequently, S1-2) the molten composition can be molded into a sheet.

[058] In one embodiment of the present disclosure, the molten composition can be extruded through an extruder die, for example, a T-mold, and subsequently, can be molded into a sheet by the commonly used casting or calendering method using a water or air cooling process. In another embodiment of the present disclosure, the molten composition can be compressed into a sheet shape by a pair of casting rolls in a cooling device equipped with the casting rolls.

[059] In this case, as the extrusion of the polymer sheet is generally carried out at high temperature, for example, from 150 °C to 300 °C, the polymer sheet extruded through the extrusion unit may have, for example, a high surface temperature of 130 °C to 200 °C immediately after extrusion, and the polymer sheet with the aforementioned surface temperature is cooled upon contact with the casting rolls. The surface temperature of the casting rolls may generally be 20 °C to 45 °C, 25 °C to 45 °C, 35 °C to 45 °C, or 25 °C.

[060] Subsequently, the S1-3) stretching step of the formed sheet can be performed.

[061] In one embodiment of the present disclosure, stretching may include Petition 870250084333, dated 09 / 18 / 2025, pp. 47 / 68 10 / 27 stretching of the polymer sheet in the same direction or in different directions. For example, stretching may include stretching of the polymer sheet in a direction parallel to each of the MD and / or TD directions, independently.

[062] In one embodiment of the present disclosure, stretching can be performed, for example, by roll-type stretching, branch-type stretching, sequential or simultaneous stretching. In one embodiment of the present disclosure, each stretching can be, for example, performed at a stretching ratio of 3 times or more, or from 5 times to 12 times, or from 6 times to 7 times. When the stretching ratio is within the aforementioned numerical range, this can have a beneficial effect on the uniformity of the thickness of the manufactured separating substrate and balance properties between the vertical and horizontal directions, but the present disclosure is not limited to this.

[063] In one embodiment of the present disclosure, S1-4), after stretching, the thinner can be extracted from the stretched sheet to form pores.

[064] In one embodiment of the present disclosure, diluent extraction can be performed using an organic solvent. The organic solvent may include solvents with high extraction efficiency and rapid drying, and may suitably include, for example, methyl ethyl ketone, methylene chloride, hexane, or a mixture thereof, but the present disclosure is not limited to this. In one embodiment of the present disclosure, the temperature at which the extraction is performed is not limited to a particular range and may include a temperature range in which the surface roughness of the porous substrate does not change.

[065] In one embodiment of the present disclosure, step S2) may include heat-setting the porous polymer sheet with the pores formed by diluent extraction as described above. According to one embodiment of the present disclosure, the separating substrate with surface roughness Sa of 30 nm to 70 nm may be provided on two surfaces of the porous polymer substrate. Petition 870250084333, dated 09 / 18 / 2025, pp. 48 / 68 11 / 27

[066] According to one embodiment of the present disclosure, the surface roughness Sa of at least one surface of the porous polymeric substrate can be from 35 nm to 70 nm.

[067] According to one embodiment of the present disclosure, when the surface roughness Sa of at least one surface of the porous polymeric substrate is in the aforementioned range, this can have a beneficial effect on suppressing the increase in separator resistance when forming the porous coating layer and ensuring the appropriate adhesion strength between the separator substrate and the porous coating layer, but the effect of the present disclosure is not limited to this.

[068] Meanwhile, in addition to measuring Sa, the method for measuring the surface roughness of the separating substrate may include known methods for measuring surface roughness in the two-dimensional (2D) direction such as Ra (Centerline Average Roughness), Rmax (Peak-to-Valley Maximum Roughness Height), Rz (Ten-Point Height), and Rg (Root Root Mean Square (RMS)). While Ra, Rmax, Rz, and Rg are a measure of 2D surface roughness (centerline direction), they cannot identify the surface roughness morphology. That is, two different surfaces may have the same value for at least one of Ra, Rmax, Rz, or Rg, but different 3D roughness morphologies, and as a consequence, the amount of impregnation of the fluid paste to form the porous coating layer may change, making it difficult to determine whether the strength characteristics have been improved or not.Considering this, the present disclosure defines the surface roughness of the separating substrate through Sa.

[069] In one embodiment of the present disclosure, the surface roughness Sa can be measured by analyzing the surface of the porous polymeric substrate using atomic force microscopy (AFM). For example, a sample of size 30 μm X 30 μm was obtained from the porous polymeric substrate from which the roughness Petition 870250084333, dated 09 / 18 / 2025, page 49 / 68 12 / 27 of the surface must be measured, and surface characteristics of each of the two surfaces are measured. In this case, the surface roughness Sa is measured by analyzing a difference in average height across the entire surface based on the average height of the surface.

[070] Next, the configuration of the porous polymeric substrate will be described by way of example. However, the porous substrate is not limited to the components described below.

[071] In one embodiment of the present disclosure, the porous polymeric substrate refers to a substrate with pores in it as an ion-conducting porous barrier that prevents electrical contact between the negative electrode and the positive electrode and allows the passage of ions. The pores are connected to each other to allow gases or liquids to pass from one side of the substrate to the other side.

[072] In one embodiment of the present disclosure, the porous polymeric substrate may include a porous polymer film including a thermoplastic resin to provide a shut-off function. Here, the shut-off function refers to a function in which, when the battery temperature becomes high, the thermoplastic resin melts to block the pores of the porous polymeric substrate and stop ion migration, thereby preventing thermal runaway in the battery.

[073] In one embodiment of the present disclosure, the thickness of the porous polymeric substrate is not limited to a particular range as long as the previously mentioned range based on the total thickness of the separator is satisfied, but may vary, for example, from 5 μm to 300 μm, specifically from 5 μm to 100 μm, from 5 μm to 50 μm, from 5 μm to 20 μm, from 5 μm to 15 μm or from 9 μm to 12 μm.

[074] In one embodiment of the present disclosure, the “thickness” of the porous polymeric substrate can be measured by the method commonly used to measure the thickness of each component of the separator. For example, the thickness of the porous polymeric substrate can be measured using a thickness measuring instrument. Petition 870250084333, dated 09 / 18 / 2025, pages 50 / 68 13 / 27 commonly used, for example, the commercially available thickness measuring instrument (Mitutoyo, VL-50S-B). Separator

[075] According to one aspect of the present disclosure, a separator including the porous polymeric substrate described above as a separator substrate and a porous coating layer formed on at least one surface of the separator substrate and including inorganic particles and a polymer binder is provided. In this case, the porous coating layer can be formed on at least one of the surfaces of the separator substrate with a surface roughness Sa of 30 nm to 160 nm.

[076] According to another aspect of the present disclosure, a separator including the porous polymeric substrate described above as a separator substrate and a porous coating layer formed on at least one surface of the separator substrate and including inorganic particles and a polymer binder is provided. In this case, the porous coating layer is formed on at least one of the surfaces of the separator substrate with a surface roughness Sa of 30 nm to 80 nm.

[077] The porous coating layer includes a large number of inorganic particles to improve the safety of the separator and a binder polymer to hold the inorganic particles together. The inorganic particles can improve the thermal resistance of the separator, and the binder polymer can provide the separator surface with adhesion capacity. In this case, when the surface of the separator substrate on which the porous coating layer is formed is flat, the adhesion force at the interface between the separator substrate and the porous coating layer may be low. However, when the surface of the separator substrate is excessively rough, a large amount of the fluid paste to form the coating layer may be impregnated into the pores of the substrate. Petition 870250084333, dated 09 / 18 / 2025, pp. 51 / 68 14 / 27 separator, and by means of the impregnated fluid paste, the inorganic particles and / or the binding polymer can infiltrate the pores of the separator substrate and / or onto the surface of the separator substrate, causing an increase in the separator's resistance. Consequently, the separator with the porous coating layer on the separator substrate according to one aspect of the present disclosure can achieve the predetermined level of surface roughness, thereby preventing the infiltration of inorganic particles and / or the binding polymer onto the surface and suppressing the increase in resistance.

[078] In one embodiment of the present disclosure, the separator can be characterized in that the adhesion force between the surface of the separator substrate with surface roughness Sa of 30 nm to 80 nm, specifically from 30 nm to 70 nm, and the porous coating layer is 30 gf / 15 mm or more. For example, the adhesion force between the surface of the separator substrate with the aforementioned range of surface roughness Sa and the porous coating layer can be from 30 gf / 15 mm to 140 gf / 15 mm, from 30 gf / 15 mm to 120 gf / 15 mm, from 30 gf / 15 mm to 100 gf / 15 mm, from 30 gf / 15 mm to 85 gf / 15 mm, or from 32 gf / 15 mm to 81 gf / 15 mm. When the adhesion strength between the separator substrate and the porous coating layer of the separator is within the previously mentioned range, this can have a beneficial effect on the efficiency of the manufacturing process of an electrode assembly using the separator and on the stability of the separator.

[079] The adhesion strength of the separator can, for example, be measured by the following method: sample the separator whose adhesion strength is to be measured over a width of 15 mm, and fix a target surface for measuring the adhesion strength to a glass slide using 18 mm wide double-sided tape (3M) so as to bring them into contact with each other. Subsequently, the resistance to peeling between the separator substrate and the porous coating layer is Petition 870250084333, dated 09 / 18 / 2025, pp. 52 / 68 15 / 27 measured using a UTM machine (Instron) under conditions of 180°, 300 mm / min.

[080] Additionally, in one embodiment of the present disclosure, the separator can be characterized in that the electrical resistance is 1 Ω or less. When the surface roughness Sa of the separator substrate is in the aforementioned range, it may be possible to reduce the degree of impregnation of the fluid paste to form the porous coating layer on the separator substrate, reduce the amount of fluid paste impregnated at the interface between the separator substrate and the porous coating layer, and reduce the amount of inorganic particles and / or the binder polymer infiltrated into the separator substrate, thereby suppressing the increase in the separator's resistance.

[081] According to one embodiment of the present disclosure, the electrical resistance of the separator can be 0.9 Ω or less. Specifically, the electrical resistance of the separator can be from 0.5 Ω to 0.9 Ω, from 0.6 Ω to 0.85 Ω, or from 0.63 Ω to 0.82 Ω.

[082] The separator resistance can be measured, for example, by means of electrochemical impedance spectroscopy (EIS). Specifically, the separator whose resistance is to be measured is punched at 19Φ to prepare a CR2016 coin cell. In this case, the positive electrode can be fabricated by applying a solution to aluminum foil, drying the solution and punching at 12Φ, the solution in which an active material (NCMA), a binder polymer (PVDF) and a conductive material (CNT) are dissolved in a solvent (NMP) in a weight ratio of 97:1:2. The negative electrode can be fabricated by applying a solution to a copper current collector, drying the solution, and punching the 12Φ solution in which an active material (Graphite), a binder polymer (SBR), and a conductive material (Super P) are dissolved in distilled water in a weight ratio of 95:0.5:4.5.The positive electrode / separator / negative electrode can be stacked in this order and immersed in the electrolyte solution containing 1M LiPFe. Petition 870250084333, dated 09 / 18 / 2025, pages 53 / 68 16 / 27 ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (3 / 7 v / v) and 2% by weight of vinylene carbonate (VC), thus assembling the coin-type cell.

[083] For EIS measurement, for example, the Solartron analytical EIS tool can be used, and resistance can be measured under frequency conditions of 100,000 Hz ~10,000 Hz.

[084] Next, the configuration of the porous coating layer will be described by way of example. However, the configuration of the porous coating layer is not limited to this.

[085] In one embodiment of the present disclosure, the porous coating layer may include the inorganic particles and the binder polymer, and all or at least part of the surface of the inorganic particles may be coated by the binder polymer. In this case, the inorganic particles are held together surface-to-surface and / or point-to-point by the binder polymer medium.

[086] For example, the inorganic particles and the binder resin in the porous coating layer may be included in a weight ratio of 99:1 to 1:99. Specifically, the inorganic particles and the binder resin in the porous coating layer may be included in the weight ratio of 95:5 to 5:95, 90:10 to 10:90, 80:20 to 10:90, 70:30 to 10:90, 60:40 to 10:90, 50:50 to 10:90, 40:60 to 15:85, 60:40 to 15:85, 70:30 to 20:80, or 20:80. The porous coating layer has the structural characteristic of a porous layer in which a plurality of micropores are formed internally, and the micropores are connected to each other to allow gases or liquids to pass from one side to the other.

[087] In one embodiment of the present disclosure, the porous coating layer may have a pore structure formed from pores or voids (interstitial volume) between the inorganic particles. The pore size or porosity (the ratio of pore volume) may be adjusted according to the particle size and the Petition 870250084333, dated 09 / 18 / 2025, pages 54 / 68 17 / 27 particle size distribution. Through this structure, it is possible to increase resistance to metallic impurities present in the electrode and suppress the shrinkage of the porous polymeric substrate, thus increasing the safety of the electrochemical device.

[088] In one embodiment of the present disclosure, the porous coating layer may include a plurality of nodes including the inorganic particles and the binder polymer covering at least part of the surface of the inorganic particles; and at least one filament formed in the form of a thread from the binder polymer of the nodes, wherein the filament has a node connection portion that extends from the node and connects the node to another node, and the node connection portion has a 3D network structure formed by interconnection of the filaments originating from the binder polymer.

[089] In one embodiment of the present disclosure, as described above, the porous coating layer may be formed by means of a Safety Reinforced Separator (SRS) manufacturing method, a Ceramic Coated Separator (CCS) manufacturing method, or any other known manufacturing method, but not limited to these.

[090] In one embodiment of the present disclosure, the inorganic particles are not limited to a particular type and may include any type of inorganic particles that are electrochemically stable. That is, the inorganic particles that can be used in the present disclosure are not limited to a particular type and may include any type of inorganic particles in which the oxidation and / or reduction reaction does not occur in the operating voltage range (e.g., 0 to 5V vs Li / Li+) of the applied electrochemical device. Non-limiting examples of inorganic particles may include at least one of BaTiOa, Pb(Zr,Ti)O3 (PZT), Pb1-xLaxZr1yTiyO3 (PLZT, 0 <x<1, 0<y<1), Pb(Mg1 / 3Nb2 / 3)O3-PbTiO3 (PMN-PT), háfnia (HfOs), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, SiO2, Y2O3, Al2Ü3, SiC ou TiO2. Petition 870250084333, dated 09 / 18 / 2025, pages 55 / 68 18 / 27

[091] In one embodiment of the present disclosure, the average particle size (D50) of the inorganic particles may be, for example, 100 nm or more. Specifically, the average particle size (D50) of the inorganic particles may be from 100 nm to 1 μm, or from 100 nm to 500 nm. When the average particle size of the inorganic particles is in the aforementioned range, this may have a beneficial effect on suppressing the increase in separator resistance, but the present disclosure is not limited to this.

[092] The particle size of inorganic particles can be measured by the method commonly used for particle size measurement, and can, for example, be measured using the Malvern Particle Size Analyzer (PSA). Additionally, the average particle size (D50) refers to a particle size at 50% of the cumulative particle size distribution, and can be measured by a laser diffraction method commonly used in the field of the technique. In this case, the laser diffraction particle size measuring instrument may include, for example, Microtrac S3500.

[093] In one embodiment of the present disclosure, the binder resin may include, for example, polyvinylidene fluoride-based resin (PVdF-based resin) and / or acrylic binder. In one embodiment of the present disclosure, the PVdF-based resin may include at least one vinylidene fluoride homopolymer (i.e., polyvinylidene fluoride), vinylidene fluoride copolymers with monomers to be polymerized with vinylidene fluoride, or a mixture thereof. In one embodiment of the present disclosure, the monomer may include, for example, fluorinated monomers and / or chlorine-based monomers. Non-limiting examples of the fluorinated monomer may include at least one vinyl fluoride; trifluoroethylene (TrFE); chlorofluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); perfluoro(alkylvinyl)ether such as perfluoro(methylvinyl)ether (PMVE), perfluoro(ethylvinyl)ether (PEVE) and perfluoro(propylvinyl)ether (PPVE); Petition 870250084333, dated 09 / 18 / 2025, pp. 56 / 68 19 / 27 perfluoro(1,3-dioxol); or perfluoro(2,2-dimethyl-1,3-dioxol) (PDD). The acrylic binder may include, for example, polyacrylic acid (PA), polyacrylonitrile (PAN), polyacrylamide (PAA), or (meth)acrylic polymer or a mixture thereof, but the present disclosure is not limited to this. (Meth)acrylic polymer refers to a polymer including (meth)acrylic acid ester as a monomer. The monomer 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-octyl(meth)acrylate, isooctyl(meth)acrylate, isononyl(meth)acrylate, lauryl(meth)acrylate, tetradecyl(meth)acrylate, or a mixture thereof, but the present disclosure is not limited to this.

[094] In one embodiment of the present disclosure, moreover, the binder polymer may include an organic binder or an aqueous binder that may be used in the porous coating layer or a mixture thereof, and is not limited to that.

[095] In one embodiment of the present disclosure, the porous coating layer is not limited to a particular thickness but provided that the previously mentioned ratio range for the total thickness of the separator is satisfied, the thickness of the porous coating layer can be, for example, from 0.5 μm to 50 μm, specifically from 0.5 μm to 10 μm, from 0.5 μm to 5 μm or from 1.5 μm to 3 μm. Electrode assembly

[096] According to another aspect of the present disclosure, an electrode assembly is provided including the separator described above, and a positive electrode and a negative electrode, each formed on each of the two surfaces of the separator.

[097] As described above, the separator according to an aspect of the present disclosure has enhanced strength and low resistance characteristics. Consequently, the electrode assembly using the separator has characteristics Petition 870250084333, dated 09 / 18 / 2025, pp. 57 / 68 20 / 27 low resistance and high yield.

[098] In one embodiment of the present disclosure, the resistance of the electrode array may be 1 Ω or less.

[099] In one embodiment of the present disclosure, the resistance of the electrode assembly can be 0.9 Ω or less. Specifically, the resistance of the electrode assembly can be from 0.5 Ω to 1 Ω, from 0.5 Ω to 0.9 Ω, from 0.5 Ω to 0.8 Ω, from 0.5 Ω to 0.7 Ω, or from 0.52 Ω to 0.62 Ω.

[0100] In one embodiment of the present disclosure, the resistance of the electrode assembly can be measured by the following method.

[0101] The positive and negative electrodes are respectively connected to the two surfaces of the separator, and pressure is applied to the positive and negative electrodes with the separator interposed between the positive and negative electrodes to prepare the electrode array with a theoretical capacity of 50 mAh. Subsequently, DC / CV charging under cutoff conditions of 4.2 V, 2.5 mA and DC discharge of 2.5 V, 50 mA are repeated three times. Subsequently, after adjustment to SOC 50%, the fully charged cell is discharged with a current of 250 mA for 30 seconds, then the voltage drop at SOC50 is recorded, and the DC resistance is calculated using R=V / I (Ohm's law). In this case, the composition of the positive electrode, the negative electrode, and the electrolyte solution can use the composition described in the method to measure the separator resistance.

[0102] In one embodiment of the present disclosure, the use of the separator using the separator substrate can provide an electrochemical device with high-throughput characteristics due to the high adhesion force with the positive electrode and the negative electrode and reduced resistance of the electrode assembly.

[0103] Next, the electrode configuration will be described by way of example. However, the present disclosure is not limited to this.

[0104] In one embodiment of the present disclosure, each of the electrode Petition 870250084333, dated 09 / 18 / 2025, pages 58 / 68 The 21 / 27 positive and negative electrode may include a current collector and an active electrode material coating on the current collector, and is not limited to a particular size or shape.

[0105] In one embodiment of the present disclosure, the active material of the positive electrode may include, for example, lithium transition metal oxide; lithium metallic iron phosphate; lithium nickel-manganese-cobalt oxide; oxide with partial substitution of another transition metal in lithium nickel-manganese-cobalt oxide; or two or more thereof, but is not limited to thereto. Specifically, the active material of the positive electrode may include, for example, layered compounds such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2) or compounds substituted with one or more transition metals; lithium manganese oxide of the formula Li1+xMn2-xO4 (where x is 0 to 0.33), LiMnOa, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); Vanadium oxide such as LV3O8, UV3O4, V2O5, Cu2V2O7; lithium nickel oxide with Ni site represented by the formula LíNíi-xMxO2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, x = 0.01 to 0.3);Manganese-lithium composite oxide represented by the formula LiMn2-xMxO2 (where M = Co, Ni, Fe, Cr, Zn or Ta, x = 0.01 to 0.1) or Li2Mn3MO8 (where M = Fe, Co, Ni, Cu or Zn); lithium metal phosphate LiMPO4 (where M = Fe, Co, Ni, or Mn); lithium nickel-manganese-cobalt oxide Li1+x(NiaCobMnc)1-xO2 (x = 0 to 0.03, a = 0.3 to 0.95, b = 0.01 to 0.35, c = 0.01 to 0.5, a+b+c=1); Lia[NibCocMndAle]1-fM1fO2 oxide with partial aluminum substitution in lithium-nickel-manganese-cobalt oxide (M1 is at least one selected from the group consisting of Zr, B, W, Mg, Ce, Hf, Ta, La, Ti, Sr, Ba, F, P and S, 0.8 <a<1,2, 0,5<b<0,99, 0<c<0,5, 0<d<0,5, 0,01<e<0,1, 0<f<0,1); óxido Li1+x(NiaCobMncMd)1-xO2 com substituição parcial de outro metal de transição em óxido de lítio níquel-manganêscobalto (x = 0 a 0,03, um = 0,3 a 0,95, b = 0,01 a 0,35, c = 0,01 a 0,5, d = 0,001 a 0,03, a+b+c+d=1, M é qualquer um selecionado a partir do grupo que consiste em Fe, V, Cr, Ti, W, Ta, Mg e Mo), compostos de dissulfeto;Fe2(MoO4)3, but is not limited to; Petition 870250084333, dated 09 / 18 / 2025, pp. 59 / 68 22 / 27 that's it.

[0106] In one embodiment of the present disclosure, the active material of the negative electrode may include, for example, lithium metals or lithium alloys, soft carbon, hard carbon, natural graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, mesocarbon microspheres, mesophase pitches, cokes derived from petroleum pitch or coal tar, silicon (Si)-based compounds (M-SiOx (M=Li, Mg, Ca, Al or Ti, 0 <x<2)) ou uma mistura dos mesmos, mas não se limita a isso. Electrochemical device

[0107] According to another aspect of the present disclosure, an electrochemical device may be provided including the electrode assembly described above and a housing that accommodates the electrode assembly.

[0108] In one embodiment of the present disclosure, the electrochemical device may include, for example, a primary battery, a secondary battery, a supercapacitor, and a double-layer electric capacitor. The secondary battery may be, more specifically, a lithium-ion secondary battery.

[0109] In one embodiment of the present disclosure, the box may include any commonly used battery box, and is not limited to a particular shape according to the use of the battery. For example, the box may have a cylindrical, prismatic, pouch, or coin shape using a can.

[0110] When the electrode assembly is completed as described above, the electrode assembly can be received in the box and the box can be sealed according to the method commonly used for the manufacture of the electrochemical device, and in this case, the electrochemical device can be, for example, a secondary lithium battery.

[0111] Next, the present revelation will be described in more detail by means of examples, but the following examples are provided for purposes of Petition 870250084333, dated 09 / 18 / 2025, pp. 60 / 68 23 / 27 illustration, and the scope of this disclosure is not limited to that. [Manufacturing of separator substrate]

[0112] A porous polymeric substrate was manufactured using the following method.

[0113] A polyethylene polymer with a molecular weight of 600,000 (g / mol) and an antioxidant agent were mixed in an extruder, followed by melting at a temperature of 200 °C and extrusion through a T-mold, and cooling and molding into a sheet on casting rolls with a surface temperature of 25 °C and manufactured from stainless steel to obtain a polymer sheet. The polymer sheet that passed through the casting rolls was stretched in the MD direction (stretch ratio of 7 times, stretching temperature of 115 °C) and TD direction (stretch ratio of 6 times, stretching temperature of 125 °C) using a sequential ram-type stretching machine at the rear of the casting rolls, and a diluent was extracted using methylene chloride. Subsequently, the resulting polymer sheet was heat-set at the temperature described in TABLE 1 below to obtain a porous polymer substrate.The heat-setting process was carried out by holding the polymer sheet in the MD and TD directions, and the thickness of the resulting porous polymer substrate was 9 μm, with a porosity of 45% by volume. TABLE 1 Classification Temperature of heat setting (°C) Example Comparative 1 117 Example 1 121 Example 2 125 Example 3 130 Example Comparative 2 134 [Separator manufacturing]

[0114] Using each of the porous polymeric substrates as prepared from Comparative Examples 1 and 2 and Examples 1 to 3 as a separating substrate, a separator was fabricated by forming a porous coating layer on two surfaces of the separating substrate by the following method. Preparation of the porous coating layer Petition 870250084333, dated 09 / 18 / 2025, pages 61 / 68 24 / 27

[0115] A PVDF-HFP binder (Mw 500,000 g / mol, HFP 15 wt%) and inorganic particles (Al2O3) were mixed in a suitable solvent at a weight ratio of 80:20 to prepare a flowable paste for coating the inorganic matter. The flowable paste as prepared for coating the inorganic matter was applied to the entire surface of the porous substrate by an immersion coating method, and dried by a wet-phase separation method to form a porous coating layer on each of the top and bottom surfaces of the porous substrate with a thickness of 3 μm.

[0116] Consequently, a separator with a total thickness of 15 μm was manufactured. [Electrode assembly manufacturing]

[0117] Each of the separators as prepared was used as a separator, a negative electrode and a positive electrode were prepared as follows and each was attached to a surface of the separator to make an electrode set. Manufacturing the negative electrode

[0118] An active material (Graphite), a binder polymer (SBR) and a conductive material (Super P) were mixed in distilled water in a weight ratio of 95:0.5:4.5 to prepare a negative electrode composition.

[0119] The negative electrode composition was applied to the surface of a copper current collector and dried to prepare a negative electrode. The amount of charge on the negative electrode was 5.3 mAh / cm2 Manufacturing the positive electrode

[0120] An active material (NCMA), a polymer binder (PVDF) and a conductive material (CNT) were mixed in a solvent (NMP) in a weight ratio of 97:1:2 to prepare a positive electrode composition.

[0121] The positive electrode composition was applied to a surface of a Petition 870250084333, dated 09 / 18 / 2025, pages 62 / 68 25 / 27 aluminum current collector and dried to prepare a positive electrode. The amount of charge on the positive electrode was 4.949 mAh / cm2 Electrode assembly

[0122] The separator as prepared was placed between the positive electrode and the negative electrode which were positioned on opposite sides of the separator, and were rolled and dried under conditions of 90 °C, 4MPa, 1s to obtain an electrode array with a theoretical capacity of 50 mAh. [Property valuation]

[0123] For each of the separator substrate, separator and electrode assembly in the order of manufacture, the properties were evaluated by the following method and the results are shown in TABLE 2 below.

[0124] In the following TABLE 2, the adhesion strength of the separator refers to the adhesion strength between the surface on which the surface roughness was measured and the porous coating layer. Measurement of the surface roughness Sa of the separating substrate.

[0125] Analysis of the porous polymeric substrate surface was performed using atomic force microscopy (AFM) to obtain a height map of a surface and the surface roughness Sa was measured by analyzing a difference in average height along the entire surface based on the average height of the surface.

[0126] Surface roughness measurement was performed on two surfaces of the separating substrate. Measuring the adhesion strength of the separator.

[0127] The separator was tested at a width of 15 mm and a target surface for measuring adhesion strength was attached to a glass slide using 18 mm wide double-sided tape (3M) so as to bring them into contact with each other. Subsequently, the resistance to peeling between the separator substrate and the porous coating layer was measured using a Petition 870250084333, dated 09 / 18 / 2025, pages 63 / 68 26 / 27 UTM machine (Instron) under 180° conditions, 300 mm / min.

[0128] The adhesion strength measurement was performed on two surfaces of the separator. Measuring the resistance of the separator

[0129] A CR2016 coin cell was manufactured and the separator resistance was measured by the EIS method as follows.

[0130] The separator to be measured was punched at 19Φ to prepare the separator. As each of the positive and negative electrodes manufactured during the fabrication of the electrode assembly was punched at 12Φ, the positive electrode / separator / negative electrode were stacked in the CR2016 coin cell in this order, an electrolyte solution containing 1M LiPF6, ethylene carbonate (EC) and ethyl methyl carbonate (EMC) (3 / 7 v / v) and 2 wt% vinylene carbonate (VC) was injected, and the lid was closed to prepare the coin cell.

[0131] The EIS measurement was performed using the Solartron analytical EIS tool, and the resistance was measured under frequency conditions from 100,000 Hz to 10,000 Hz. Measuring the resistance of the electrode array.

[0132] To measure the resistance of the separator, the resistance of the prepared electrode assembly was measured by the following method.

[0133] DC / CV charging under cutoff conditions of 4.2 V, 2.5 mA and DC discharge of 2.5 V, 50 mA were repeated three times. Subsequently, after adjustment to SOC 50%, the fully charged cell was discharged with a current of 250 mA for 30 seconds, the voltage drop at SOC50 was recorded, and the DC resistance was calculated using R=V / I (Ohm's law). TABLE 2 Classification Substrate separator Separator Electrode assembly Roughness Strength Resistance Resistance Petition 870250084333, dated 09 / 18 / 2025, pages 64 / 68 27 / 27 Surface area (Sa) Adhesion (gf / 15mm) (Ohm, Ω) (Ohm, Ω) Comparative Example 1 28.2 7 0.45 0.48 Example 1 36.5 32 0.63 0.52 Example 2 54.8 51 0.78 0.56 Example 3 69.1 81 0.82 0.62 Comparative Example 2 90.4 197 2.32 1.18

[0134] As can be observed from TABLE 1 and TABLE 2 above, the porous polymeric substrate as the separator substrate obtained by thermosetting at a temperature between 119 °C and 132 °C has a surface roughness Sa of 30 nm to 70 nm, and through this, it was confirmed that the porous polymeric substrate maintains the ideal level of adhesion strength and has low resistance. Furthermore, it was confirmed that it is possible to significantly reduce the resistance of the electrode array that uses it.

[0135] Conversely, it was confirmed that the porous polymeric substrate, as the separator substrate obtained by thermosetting in the temperature range outside the previously mentioned range, has a surface roughness Sa outside the range between 30 nm and 70 nm. In particular, in the case of Comparative Example 1 with a surface roughness Sa of less than 30 nm, it was confirmed that the separator has low resistance but poor adhesion strength, and in the case of Comparative Example 2 with a surface roughness Sa of more than 70 nm, the adhesion strength is very high and poor properties are found in terms of the separator's resistance, and thus the resistance of the electrode array using it was very high when measured. Petition 870250084333, dated 09 / 18 / 2025, pages 65 / 68

Claims

1 / 2 CLAIMS 1. Separating substrate as a porous polymeric substrate CHARACTERIZED in that it has a surface roughness (Sa) of 30 nm to 80 nm on at least one surface.

2. Separating substrate, according to claim 1, CHARACTERIZED in that the surface roughness (Sa) of two surfaces of the porous polymeric substrate is from 30 nm to 70 nm.

3. Separator CHARACTERIZED in that it comprises: the separator substrate as defined in claim 1; and a porous coating layer present on at least one of the surfaces of the separator substrate with a surface roughness (Sa) of 30 nm to 80 nm, the porous coating layer including inorganic particles and a binding polymer.

4. Separator, according to claim 3, CHARACTERIZED in that an adhesion force between the separator substrate and the porous coating layer is 30 gf / 15 mm or more.

5. Separator, according to claim 4, CHARACTERIZED in that the adhesion force between the separator substrate and the porous coating layer is from 30 gf / 15 mm to 140 gf / 15 mm.

6. Separator, according to claim 3, CHARACTERIZED in that the electrical resistance of the separator is 1 Ω or less.

7. Separator, according to claim 6, CHARACTERIZED in that the electrical resistance of the separator is 0.9 Ω or less.

8. Separator, according to claim 3, CHARACTERIZED in that the average particle size of the inorganic particles is 100 nm or more.

9. Electrode assembly CHARACTERIZED in that it comprises: Petition 870250084333, dated 09 / 18 / 2025, page 66 / 68 2 / 2 the separator as defined in any of claims 3 to 8; and a positive electrode and a negative electrode, each present on each of the two surfaces of the separator.

10. Electrode assembly according to claim 9, CHARACTERIZED in that the resistance of the electrode assembly is 1 Ω or less.

11. Electrode assembly according to claim 10, CHARACTERIZED in that the resistance of the electrode assembly is 0.9 Ω or less.

12. Electrochemical device CHARACTERIZED in that it comprises: the electrode assembly as defined in claim 9; and a housing that accommodates the electrode assembly.

13. Method for manufacturing a separator substrate, the method CHARACTERIZED by the fact that it comprises the steps of: S1) extruding a fluid polymer paste to obtain a polymer sheet; and S2) heat-setting the resulting polymer sheet, wherein the heat-setting in step S2 is carried out at a temperature between 119 °C and 132 °C. Petition 870250084333, dated 09 / 18 / 2025, pp. 67 / 68