Separator for electrochemical device and electrochemical device comprising same

Abstract

The present invention relates to a separator for an electrochemical device and an electrochemical device comprising same, and specifically relates to a separator, for an electrochemical device, which can improve adhesion with an electrode due to the inclusion of a first adhesive layer and a second adhesive layer on the respective sides of a porous polymer substrate provided with coating layers, and an electrochemical device comprising same.

Description

Separator for electrochemical devices and electrochemical devices containing the same

[0001] This invention claims the benefit of the filing dates of Korean Patent Application No. 10-2024-0095495, filed with the Korean Intellectual Property Office on July 19, 2024, and Korean Patent Application No. 10-2025-0088044, filed with the Korean Intellectual Property Office on July 1, 2025, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to a separator for an electrochemical device and an electrochemical device including the same, and more particularly, to a separator for an electrochemical device capable of improving adhesive strength with an electrode by including a first adhesive layer and a second adhesive layer on both sides of a porous polymer substrate having a coating layer, and to an electrochemical device including the same.

[0003] Among the components of electrochemical devices, the separator comprises a porous polymer substrate located between the anode and cathode. It isolates the anode and cathode, prevents electrical short-circuiting between the two electrodes, and allows the passage of electrolytes and ions. While the separator itself does not participate in electrochemical reactions, its physical properties, such as wettability with electrolyte, degree of porosity, and thermal shrinkage, influence the performance and safety of the electrochemical device.

[0004] Accordingly, various methods have been attempted to enhance the physical properties of the separator by adding a coating layer to a porous polymer substrate and adding various substances to the coating layer to change the properties of the coating layer. For example, an inorganic substance may be added to the coating layer to enhance the mechanical strength of the separator, or an inorganic substance or hydrate may be added to the coating layer to enhance the flame retardancy and heat resistance of the polymer substrate. Furthermore, an adhesive layer may be added on the coating layer and various substances may be added to the adhesive layer to improve the properties of the adhesive layer.

[0005] If adhesion of the separator and electrode is possible, it can be applied to assembly processes such as lamination and hot press, and has the advantage of being able to closely contact the electrode interface and separator and secure the strength of the battery cell even under electrolyte injection.

[0006] Meanwhile, when an adhesive layer is additionally coated on the coating layer to provide adhesion to the separator, the coating is generally performed using the same binder on both sides.

[0007] However, in these cases, a problem may arise where the adhesive strength varies depending on the electrode.

[0008] Accordingly, research on binder coating suited to the characteristics of each electrode was necessary to improve the adhesive strength of the separator.

[0009] The technical problem to be achieved by the present invention is to provide a separator for an electrochemical device capable of improving adhesive strength with an electrode by including a first adhesive layer and a second adhesive layer on both sides of a porous polymer substrate having a coating layer, and an electrochemical device including the same.

[0010] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned can be clearly understood by those skilled in the art from the description below.

[0011] One embodiment of the present invention provides a separator for an electrochemical device, comprising: a porous polymer substrate; a coating layer provided on both sides of the porous polymer substrate and including inorganic particles; a first adhesive layer including a first polymer binder on one surface of the porous polymer substrate provided with the coating layer; and a second adhesive layer including a second polymer binder on the other surface of the porous polymer substrate provided with the coating layer.

[0012] According to one embodiment of the present invention, the thickness of the coating layer may be less than 2.0 μm.

[0013] According to one embodiment of the present invention, the first polymer binder may be different from the second polymer binder.

[0014] According to one embodiment of the present invention, the first polymer binder may be a fluorine-based polymer binder.

[0015] According to one embodiment of the present invention, the second polymer binder may be a urethane-based polymer binder.

[0016] According to one embodiment of the present invention, the urethane-based polymer binder may be a urethane-acrylic copolymer.

[0017] According to one embodiment of the present invention, the first adhesive layer may be formed on the positive electrode orientation surface of the electrochemical device.

[0018] According to one embodiment of the present invention, the second adhesive layer may be formed on the cathode orientation surface of the electrochemical device.

[0019] According to one embodiment of the present invention, the anodic adhesive strength of the first adhesive layer may be greater than the anodic adhesive strength of the second adhesive layer.

[0020] According to one embodiment of the present invention, the negative adhesive strength of the second adhesive layer may be greater than the negative adhesive strength of the first adhesive layer.

[0021] One embodiment of the present invention provides an electrochemical device comprising: an anode; a cathode; and a separator interposed between the anode and the cathode, as described above.

[0022] A separator for an electrochemical device according to one embodiment of the present invention can improve adhesion to an electrode by including a first adhesive layer and a second adhesive layer on both sides of a porous polymer substrate having a coating layer.

[0023] An electrochemical device according to one embodiment of the present invention can contribute to improving battery characteristics by improving adhesive strength with each electrode.

[0024] Figure 1 is a schematic diagram of a separator for an electrochemical device according to one embodiment of the present invention.

[0025] Figure 2 is a schematic diagram showing a structure in which a separator for an electrochemical device according to one embodiment of the present invention is placed between electrodes.

[0026] Figure 3 is a schematic diagram of a separator for an electrochemical device according to Comparative Example 7 according to one embodiment of the present invention.

[0027] Figure 4 is a schematic diagram showing a structure in which a separator for an electrochemical device of Comparative Example 7 according to one embodiment of the present invention is placed between electrodes.

[0028] In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0029] In this specification, “A and / or B” means “A and B, or A or B.”

[0030] In this specification, “about,” “approximately,” and “substantially” are used to mean a range of or approximation to a numerical value or degree, taking into account inherent manufacturing and material tolerances, and are used to prevent infringers from unfairly using the disclosure, which mentions exact or absolute numbers provided to aid understanding of the present invention.

[0031] In this specification, when it is said that a component is “on”, this does not exclude other components being placed therebetween, unless otherwise specifically stated, but rather means that other components may be placed thereon.

[0032] In this specification, the characteristic of having pores means that the object includes a plurality of pores and the pores are interconnected with each other, thereby allowing gaseous and / or liquid fluids to pass from one side of the object to the other side.

[0033] In this specification, the separator has a porous characteristic including a plurality of pores, and acts as a porous ion-conducting barrier that allows ions to pass while blocking electrical contact between the cathode and the anode in an electrochemical device.

[0034] Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings. The drawings may be exaggerated, omitted, or schematically illustrated to explain or emphasize the contents of an embodiment of the present invention.

[0035] Hereinafter, the present invention will be described in more detail.

[0036] Figure 1 is a schematic diagram of a separator for an electrochemical device according to one embodiment of the present invention.

[0037] One embodiment of the present invention includes a separator (100) for an electrochemical device, which includes a porous polymer substrate (110); a coating layer (130) provided on both sides of the porous polymer substrate and including inorganic particles; a first adhesive layer (150) including a first polymer binder on one surface of the porous polymer substrate provided with the coating layer; and a second adhesive layer (170) including a second polymer binder on the other surface of the porous polymer substrate provided with the coating layer.

[0038] A separator for an electrochemical device according to one embodiment of the present invention can improve adhesion to an electrode by including a first adhesive layer and a second adhesive layer on both sides of a porous polymer substrate having a coating layer.

[0039] The above electrochemical device separator (100) includes a porous polymer substrate (110). As described above, the electrochemical device separator (100) includes the porous polymer substrate (110), thereby allowing lithium ions to pass through while blocking electrical contact, and can implement a shutdown function at an appropriate temperature.

[0040] According to one embodiment of the present invention, the porous polymer substrate (110) may be manufactured using a polyolefin-based resin as a base resin. Examples of the polyolefin-based resin include polyethylene, polypropylene, polypentene, etc., and the porous polymer substrate may include one or more of these. A porous separation membrane manufactured using such a polyolefin-based resin as a base resin, i.e., having a large number of pores, can provide a shutdown function at an appropriate temperature.

[0041] According to one embodiment of the present invention, the weight average molecular weight of the polyolefin resin may be 500,000 or more and 1,500,000 or less. By controlling the weight average molecular weight of the polyolefin resin within the above-described range, the compression resistance of the separator can be improved. Furthermore, when different types of polyolefin resins are mixed and used or the separator is formed with a multilayer structure made of different types of polyolefin resins, the weight average molecular weight of the polyolefin resin can be calculated by adding the weight average molecular weights according to the content ratio of each polyolefin resin.

[0042] In this specification, the weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC: gel permeation chromatography, PL GPC220, Agilent Technologies), and the measurement conditions can be set as follows.

[0043] - Column: PL Olexis (Polymer Laboratories)

[0044] - Solvent: TCB (Trichlorobenzene)

[0045] - Flow rate: 1.0 ml / min

[0046] - Sample concentration: 1.0 mg / ml

[0047] - Injection volume: 200 ㎕

[0048] - Column temperature: 160 ℃

[0049] - Detector: Agilent High Temperature RI detector

[0050] - Standard: Polystyrene (corrected with a cubic function)

[0051] According to one embodiment of the present invention, the porous polymer substrate (110) may be manufactured by a method (wet method) in which a polyolefin resin is mixed with a plasticizer at a high temperature to form a single phase, the polymer material and the plasticizer are phase-separated during a cooling process, the plasticizer is extracted to form pores, and then stretching and heat-setting are performed. In addition, the porous polymer substrate using the polyolefin resin may have a core portion made of a mixture of polyethylene and polypropylene and a polyethylene skin portion laminated on both sides of the core portion.

[0052] According to one embodiment of the present invention, the average size of the pores and the maximum size of the pores of the porous polymer substrate (110) can be easily manufactured by a person skilled in the art by controlling the mixing ratio of the plasticizer, the stretching ratio, the heat-setting treatment temperature, etc. to conform to the scope of the present invention.

[0053] According to one embodiment of the present invention, the thickness of the porous polymer substrate (110) may be 1 ㎛ or more and 50 ㎛ or less. Specifically, the thickness of the porous polymer substrate may be 2 ㎛ or more and 45 ㎛ or less, 3 ㎛ or more and 40 ㎛ or less, 4 ㎛ or more and 35 ㎛ or less, 5 ㎛ or more and 30 ㎛ or less, 6 ㎛ or more and 25 ㎛ or less, 7 ㎛ or more and 20 ㎛ or less, or 8 ㎛ or more and 15 ㎛ or less. By controlling the thickness of the porous polymer substrate within the above-described range, the energy density of the battery can be improved.

[0054] According to one embodiment of the present invention, the porosity of the porous polymer substrate (110) may be 10% by volume or more and 90% by volume or less. Specifically, the porosity of the porous polymer substrate may be 10% by volume or more and 90% by volume or less, 20% by volume or more and 80% by volume or less, 30% by volume or more and 70% by volume or less, or 40% by volume or more and 60% by volume or less. By controlling the porosity of the porous polymer substrate within the above-described range, the permeability of lithium ions through the separator can be controlled.

[0055] According to one embodiment of the present invention, the coating layer (130) is provided on both sides of the porous polymer substrate (110). As described above, the electrochemical device separator (100) includes the coating layer (130) provided on both sides of the porous polymer substrate (110), thereby improving the heat resistance of the separator, improving the mechanical properties, and preventing the separator from shrinking at high temperatures and causing an electrical short circuit in the electrode.

[0056] According to one embodiment of the present invention, the coating layer (130) includes inorganic particles. As described above, by including the inorganic particles in the coating layer, the heat resistance of the separator is improved, the mechanical properties are improved, the separator shrinks at high temperatures, preventing an electrical short circuit of the electrode, and pores can be formed within the coating layer.

[0057] According to one embodiment of the present invention, the coating layer (130) may further include a water-soluble polymer. As described above, by further including the water-soluble polymer in the coating layer, pores may be formed within the coating layer.

[0058] According to one embodiment of the present invention, the coating layer (130) may be formed by inorganic particles being bound by a water-soluble polymer and accumulated within the side. The pores within the coating layer may be derived from interstitial volume, which is an empty space between the inorganic particles.

[0059] According to one embodiment of the present invention, the coating layer (130) may include a plurality of pores. Specifically, the coating layer may be a porous coating layer. More specifically, the coating layer may be a porous coating layer including a plurality of pores therein. As described above, by including a plurality of pores, the coating layer can physically block the negative electrode and the positive electrode while allowing lithium ions to pass through and current to flow.

[0060] According to one embodiment of the present invention, the water-soluble polymer may be an acrylic binder, a polyvinylidene binder, or a combination thereof. The combination of the acrylic binder and the polyvinylidene binder may be a mixture of the acrylic binder and the polyvinylidene binder, a copolymer containing the acrylic repeating unit and the polyvinylidene repeating unit, or a hybrid of the acrylic binder and the polyvinylidene binder. In addition, the polyvinylidene binder may be a copolymer of polyvinylidene fluoride (PVdF) and hexafluoropropylene (HFP). By selecting the polymer binder particles described above, the porosity of the separator can be maintained, and the adhesion between the electrode and the separator can be improved in the lamination process of the battery, thereby facilitating the manufacture of the battery, and stably implementing the stacking process. Furthermore, the porosity of the separator can be maintained, and the adhesive strength can be maintained even when the coating layer is wetted by the electrolyte after battery activation. Furthermore, the stiffness of the battery can be improved, and banding of the separator can be prevented.

[0061] According to one embodiment of the present invention, the acrylic binder is a polymer containing a carboxylic acid ester as a repeating unit, and may preferably be a (meth)acrylic acid ester or an acrylic-styrene copolymer.

[0062] According to one embodiment of the present invention, the (meth)acrylic acid ester is methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, n-amyl (meth)acrylate, i-amyl (meth)acrylate, hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxyethyl (meth)acrylate, ethylene glycol (meth)acrylate, di(meth)acrylate, propylene glycol (meth)acrylate, Examples thereof include trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, allyl (meth)acrylate, and ethylene di(meth)acrylate, and the like may be at least one selected from these. Among these, at least one selected from methyl (meth)acrylate, ethyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate is preferable, and methyl (meth)acrylate is particularly preferable.

[0063] According to one embodiment of the present invention, the acrylic-styrene copolymer may include an acrylic binder, and the acrylic binder may be a polyacrylate. For example, the binder may be at least one selected from the group consisting of styrene-butyl acrylate, styrene-butadiene rubber, nitrile-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-butadiene-styrene rubber, and acrylate polymers, and more specifically, may be a copolymer including acrylate.

[0064] According to one embodiment of the present invention, the polyvinylidene-based binder may be a polyvinylidene-based binder having a hexafluoropropylene (HFP) content of 1 wt% or more and 50 wt% or less. Specifically, the hexafluoropropylene (HFP) content in the polyvinylidene-based binder may be 1 wt% or more and 50 wt% or less, 2 wt% or more and 45 wt% or less, 3 wt% or more and 40 wt% or less, 4 wt% or more and 35 wt% or less, 5 wt% or more and 30 wt% or less, 7 wt% or more and 25 wt% or less, or 10 wt% or more and 20 wt% or less. As described above, by selecting the polyvinylidene-based binder as a polyvinylidene-based binder having a hexafluoropropylene content of 1 wt% or more and 50 wt% or less, the porosity of the separator can be maintained, and the adhesive strength can be maintained even when the coating layer is wetted by the electrolyte after battery activation. In the present specification, the degree of substitution of the polyvinylidene-based binder may mean the weight ratio containing hexafluoropropylene.

[0065] According to one embodiment of the present invention, when combining the acrylic binder and the polyvinylidene binder in the coating layer (130), the weight ratio may be 9:1 to 1:9. Specifically, when combining the acrylic binder and the polyvinylidene binder in the coating layer (130), the weight ratio may be 8:1 to 1:8, 7:1 to 1:7, 6:1 to 1:6, 5:1 to 1:5, 4:1 to 1:4, 3:1 to 1:3, or 2:1 to 1:2. By adjusting the weight ratio of the acrylic binder and the polyvinylidene binder within the above-described range, the wet adhesiveness and the dry adhesiveness of the separator for an electrochemical device can be simultaneously improved.

[0066] According to one embodiment of the present invention, the average particle diameter (D50) of the water-soluble polymer is not particularly limited, but is preferably in the range of 0.1 ㎛ to 1 ㎛ in order to form a coating layer (130) with a uniform thickness and an appropriate porosity. Specifically, the average particle diameter (D50) of the water-soluble polymer may be 0.1 ㎛ to 0.8 ㎛, 0.1 ㎛ to 0.6 ㎛, 0.1 ㎛ to 0.4 ㎛, or 0.1 ㎛ to 0.2 ㎛. By controlling the average particle diameter (D50) of the water-soluble polymer within the above-described range, the dispersibility in the slurry prepared for manufacturing the coating layer can be improved, and the thickness of the formed coating layer can be reduced.

[0067] According to one embodiment of the present invention, the content of the water-soluble polymer may be 1 part by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the coating layer (130). Specifically, the content of the water-soluble polymer may be 1 part by weight or more and 9 parts by weight or less, 1 part by weight or more and 8 parts by weight or less, 1 part by weight or more and 7 parts by weight or less, 1 part by weight or more and 6 parts by weight or less, 1 part by weight or more and 5 parts by weight or less, 1 part by weight or more and 4 parts by weight or less, or 2 parts by weight or more and 4 parts by weight or less with respect to 100 parts by weight of the coating layer (130). By controlling the content of the water-soluble polymer within the above-described range, the ease of assembly can be improved in the process of assembling the electrode.

[0068] According to one embodiment of the present invention, the inorganic particles that can be used in the coating layer (130) are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in one embodiment of the present invention are those that can be used in the operating voltage range of the applied electrochemical device (e.g., Li / Li). + There are no particular limitations as long as no oxidation and / or reduction reaction occurs at a voltage of 0 V to 5 V (as a reference).

[0069] According to one embodiment of the present invention, non-limiting examples of the 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, Mg(OH)2, NiO, CaO, ZnO, ZrO2, SiO2, Y2O3, Al2O3, SiC, Al(OH)3, TiO2, boehmite, aluminum peroxide, zinc tin hydroxide (ZnSn(OH)6), tin-zinc oxide (Zn2SnO4, ZnSnO3), antimony trioxide (Sb2O3), antimony tetroxide (Sb2O4), antimony pentoxide (Sb2O5), etc., and may include one or more of these.

[0070] According to one embodiment of the present invention, the average particle diameter (D50) of the inorganic particles is not particularly limited, but is preferably in the range of 0.1 ㎛ to 1 ㎛ in order to form a coating layer (130) with a uniform thickness and an appropriate porosity. Specifically, the average particle diameter (D50) of the inorganic particles may be 0.2 ㎛ to 0.9 ㎛, 0.3 ㎛ to 0.8 ㎛, 0.4 ㎛ to 0.7 ㎛, or 0.5 ㎛ to 0.6 ㎛. Specifically, when it is less than 0.1 ㎛, the dispersibility of the inorganic particles in the slurry prepared for manufacturing the coating layer may be reduced, and when it exceeds 1 ㎛, the thickness of the formed coating layer may increase.

[0071] In this specification, "D50 particle size" means the particle size at the 50% point of the cumulative distribution of particle numbers according to particle size. The particle size can be measured using a laser diffraction method. Specifically, after the powder to be measured is dispersed in a dispersion medium, it is introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac S3500), and when the particles pass through the laser beam, the difference in the diffraction pattern according to the particle size is measured to calculate the particle size distribution. By calculating the particle diameter at the point where it becomes 50% of the cumulative distribution of particle numbers according to particle size in the measuring device, the D50 particle size can be measured.

[0072] According to one embodiment of the present invention, the content of the inorganic particles may be 90 parts by weight or more and less than 100 parts by weight with respect to 100 parts by weight of the coating layer (130). Specifically, the content of the inorganic particles may be 92 parts by weight or more and 98 parts by weight or less or 94 parts by weight or more and 96 parts by weight or less with respect to 100 parts by weight of the coating layer (130). By controlling the content of the inorganic particles included in the coating layer (130) within the above-described range, the heat resistance of the separator can be improved, thereby ensuring the safety of the battery.

[0073] According to one embodiment of the present invention, the thickness of the coating layer (130) on one side of the porous polymer substrate (110) may be less than 2.0 ㎛. Specifically, the thickness of the coating layer (130) may be more than 0 ㎛ and less than 2.0 ㎛, 0.1 ㎛ or more and 1.9 ㎛ or less, 0.2 ㎛ or more and 1.8 ㎛ or less, 0.3 ㎛ or more and 1.7 ㎛ or less, 0.4 ㎛ or more and 1.6 ㎛ or less, or 0.5 ㎛ or more and 1.5 ㎛ or less. If the thickness is less than the above-described range, the heat resistance of the coating layer may decrease and the adhesive strength may be reduced, and if the thickness is more than the above-described range, the air permeability and resistance may increase, and the thickness of the entire separator may become thicker, which may negatively affect battery assembly.

[0074] In one embodiment of the present invention, the thickness of the porous polymer substrate (110) and / or the coating layer (130) can be measured using a contact thickness measuring device. For example, the contact thickness measuring device may be VL-50S-B from Mitutoyo.

[0075] According to one embodiment of the present invention, the separator (100) for an electrochemical device includes a first adhesive layer (150) containing a first polymer binder on one surface of a porous polymer substrate (110) provided with the coating layer (130). As described above, the separator for an electrochemical device includes a first adhesive layer containing a first polymer binder on one surface of the porous polymer substrate provided with the coating layer, thereby ensuring adhesive strength between the electrode and the separator during the lamination process of the separator with the electrode.

[0076] According to one embodiment of the present invention, the electrochemical device separator (100) includes a second adhesive layer (170) containing a second polymer binder on the other surface of the porous polymer substrate (110) provided with the coating layer (130). As described above, the electrochemical device separator includes a second adhesive layer containing a second polymer binder on the other surface of the porous polymer substrate provided with the coating layer, thereby ensuring adhesive strength between the electrode and the separator during the lamination process of the separator and the electrode.

[0077] According to one embodiment of the present invention, the first polymer binder may be different from the second polymer binder. As described above, by selecting the first polymer binder to be different from the second polymer binder, the adhesive strength can be prevented from varying depending on the electrode, and the adhesive strength with each electrode can be improved.

[0078] According to one embodiment of the present invention, the first polymer binder may be a fluorinated polymer binder. Specifically, the first polymer binder may be a polyvinylidene-based binder. More specifically, the polyvinylidene-based binder may be a polyvinylidene fluoride (PVdF, polyvinylidene difluoride)-based binder. As described above, by selecting a fluorinated polymer binder as the first polymer binder, the adhesive strength between the separator and the anode can be improved.

[0079] According to one embodiment of the present invention, the D50 particle size of the first polymer binder may be 100 nm or more and 500 nm or less. Specifically, the D50 particle size of the first polymer binder may be 150 nm or more and 450 nm or less, 150 nm or more and 400 nm or less, 150 nm or more and 350 nm or less, 150 nm or more and 300 nm or less, or 150 nm or more and 250 nm or less. By controlling the D50 particle size of the first polymer binder within the above-described range, the formation of the first adhesive layer can be facilitated.

[0080] According to one embodiment of the present invention, the second polymer binder may be a urethane-based polymer binder. Specifically, the urethane-based polymer may include, but is not limited to, a polyurethane polymer obtained by polymerizing only urethane monomers; a copolymer of a urethane monomer and an acrylic monomer; or two or more thereof. As described above, the second polymer binder can improve the adhesive strength between the separator and the negative electrode by selecting a urethane-based polymer binder.

[0081] According to one embodiment of the present invention, the urethane-based polymer binder may be a urethane-acrylic copolymer. Specifically, the urethane-acrylic copolymer may have an intermediate structure, for example, polyester polyol, polyether polyol, polycarbonate polyol, polycarprolactone polyol, tetrahydrofurane-propyleneoxide ring opening copolymer, polybutadiene diol, polydimethylsiloxane diol, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexane. It is possible to use those synthesized from dimethanol (1,4-cyclohexane dimethanol), bisphenol A, hydrogenated bisphenol A, 2,4-toluene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, 1,5-napthalene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, bisphenol A propylene oxide modified diacrylate, etc.As described above, the urethane-based polymer binder can improve the adhesion between the separator and the negative electrode by selecting a urethane-acrylic copolymer.

[0082] According to one embodiment of the present invention, the D50 particle size of the second polymer binder may be 100 nm or more and 500 nm or less. Specifically, the D50 particle size of the second polymer binder may be 150 nm or more and 450 nm or less, 150 nm or more and 400 nm or less, 150 nm or more and 350 nm or less, 150 nm or more and 300 nm or less, or 150 nm or more and 250 nm or less. By controlling the D50 particle size of the second polymer binder within the above-described range, the formation of the second adhesive layer can be facilitated.

[0083] Figure 2 is a schematic diagram showing a structure in which a separator for an electrochemical device according to one embodiment of the present invention is placed between electrodes.

[0084] According to one embodiment of the present invention, the first adhesive layer (150) may be formed on the positive electrode (200) alignment surface of the electrochemical device. As described above, the first adhesive layer is formed on the positive electrode alignment surface of the electrochemical device, so that the first polymer binder included in the first adhesive layer can sufficiently exhibit adhesive strength with the positive electrode.

[0085] According to one embodiment of the present invention, the second adhesive layer (170) may be formed on the negative electrode (300) alignment surface of the electrochemical device. As described above, the second adhesive layer is formed on the negative electrode alignment surface of the electrochemical device, so that the second polymer binder included in the second adhesive layer can sufficiently exhibit adhesive strength with the negative electrode.

[0086] According to one embodiment of the present invention, the positive electrode (200) adhesive strength of the first adhesive layer (150) may be greater than the positive electrode (200) adhesive strength of the second adhesive layer (170). As described above, since the positive electrode adhesive strength of the first adhesive layer is greater than the positive electrode adhesive strength of the second adhesive layer, the first polymer binder included in the first adhesive layer can sufficiently exhibit adhesive strength with the positive electrode.

[0087] According to one embodiment of the present invention, the anode (200) adhesive strength of the first adhesive layer (150) may be 40 gf / 25mm or more. Specifically, the anode adhesive strength of the first adhesive layer may be 40 gf / 25mm or more and 90 gf / 25mm or less, 40 gf / 25mm or more and 88 gf / 25mm or less, 40 gf / 25mm or more and 86 gf / 25mm or less, 40 gf / 25mm or more and 84 gf / 25mm or less, 40 gf / 25mm or more and 82 gf / 25mm or less, 40 gf / 25mm or more and 80 gf / 25mm or less, 40 gf / 25mm or more and 78 gf / 25mm or less, or 40 gf / 25mm or more and 76 gf / 25mm or less. By controlling the anode adhesive strength of the first adhesive layer within the above-described range, the adhesive strength between the separator and the anode can be improved.

[0088] According to one embodiment of the present invention, the negative electrode (300) adhesive strength of the second adhesive layer (170) may be greater than the negative electrode adhesive strength of the first adhesive layer. As described above, since the negative electrode adhesive strength of the second adhesive layer is greater than the negative electrode adhesive strength of the first adhesive layer, the second polymer binder included in the second adhesive layer can sufficiently exhibit adhesive strength with the negative electrode.

[0089] According to one embodiment of the present invention, the negative electrode (300) adhesive strength of the adhesive layer (170) may be 40 gf / 25mm or more. Specifically, the negative electrode adhesive strength of the second adhesive layer may be 40 gf / 25mm or more and 50 gf / 25mm or less, 40 gf / 25mm or more and 48 gf / 25mm or less, 40 gf / 25mm or more and 46 gf / 25mm or less, 40 gf / 25mm or more and 44 gf / 25mm or less, or 40 gf / 25mm or more and 43 gf / 25mm or less. By controlling the negative electrode adhesive strength of the second adhesive layer within the above-described range, the adhesive strength between the separator and the negative electrode can be improved.

[0090] One embodiment of the present invention includes an electrochemical device including an anode (200); a cathode (300); and a separator (100) interposed between the anode (200) and the cathode (300).

[0091] An electrochemical device according to one embodiment of the present invention can contribute to improving battery characteristics by improving adhesive strength with each electrode.

[0092] In one embodiment of the present invention, the electrochemical device is a device that converts chemical energy into electrical energy through an electrochemical reaction, and is a concept encompassing a primary battery and a secondary battery. In the present specification, the secondary battery is capable of charging and discharging, and refers to a lithium secondary battery, a nickel-cadmium battery, a nickel-hydrogen battery, etc. The lithium secondary battery uses lithium ions as an ion conductor, and examples thereof include, but are not limited to, a non-aqueous electrolyte secondary battery including a liquid electrolyte, an all-solid-state battery including a solid electrolyte, a lithium polymer battery including a gel polymer electrolyte, and a lithium metal battery using lithium metal as an anode.

[0093] According to one embodiment of the present invention, the positive electrode (200) has a positive electrode current collector and a positive electrode active material layer including a positive electrode active material, a conductive material, and a binder resin on at least one surface of the positive electrode current collector. The positive electrode active material is a layered compound such as lithium manganese oxide (LiMn2O4, LiMnO2, etc.), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; chemical formula Li 1+x Mn 2-x Lithium manganese oxides such as O4 (where x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, LiV3O4, V2O5, Cu2V2O7; chemical formula LiNi 1-x M x Ni-site type lithium nickel oxide represented by O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B or Ga and x = 0.01 to 0.3); chemical formula LiMn1-xM x A lithium manganese composite oxide represented by O2 (wherein, M = Co, Ni, Fe, Cr, Zn or Ta, and x = 0.01 to 0.1) or Li2Mn3MO8 (wherein, M = Fe, Co, Ni, Cu or Zn); LiMn2O4 in which a portion of Li in the chemical formula is replaced by an alkaline earth metal ion; a disulfide compound; or a mixture of two or more of Fe2(MoO4)3.

[0094] According to one embodiment of the present invention, the negative electrode (300) has a negative electrode current collector and a negative electrode active material layer including a negative electrode active material, a conductive material, and a binder resin on at least one surface of the current collector. The negative electrode includes carbon such as lithium metal oxide, non-graphitizable carbon, and graphite carbon as the negative electrode active material; LixFe2O3(0≤x≤1), Li x WO2(0≤x≤1), Sn x Me 1-x Me'y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, elements of group 1, 2, and 3 of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8) 등의 금속 복합 산화물; 리튬 금속; 리튬 합금; 규소계 합금; 주석계 합금; SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, 및 Bi2O5등의 금속 산화물; 폴리아세틸렌 등의 도전성 고분자; Li-Co-Ni 계 재료; 티타늄 산화물 중 선택된 1종 또는 2종 이상의 혼합물을 포함할 수 있다.

[0095] According to one embodiment of the present invention, the conductive material may be, for example, one selected from the group consisting of graphite, carbon black, carbon fibers or metal fibers, metal powders, conductive whiskers, conductive metal oxides, activated carbon, and polyphenylene derivatives, or a mixture of two or more conductive materials among these. More specifically, the conductive material may be one selected from the group consisting of natural graphite, artificial graphite, super-p, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, Denka black, aluminum powder, nickel powder, zinc oxide, potassium titanate, and titanium oxide, or a mixture of two or more conductive materials among these.

[0096] According to one embodiment of the present invention, the current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, and for example, stainless steel, copper, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used.

[0097] According to one embodiment of the present invention, the binder resin may be a polymer commonly used in electrodes in the art. Non-limiting examples of such binder resins include polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-cotrichloroethylene, polymethylmethacrylate, polyethylhexyl acrylate, polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butyrate, and cellulose acetate propionate. Examples thereof include, but are not limited to, cellulose acetatepropionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, and carboxyl methyl cellulose.

[0098] According to one embodiment of the present invention, the positive electrode slurry for manufacturing the positive electrode active material layer may include a dispersant, and the dispersant may be a pyrrolidone-based compound. Specifically, it may be N-methylpyrrolidone (ADC-01, LG Chemical).

[0099] According to one embodiment of the present invention, the content of the dispersant included in the positive electrode slurry may be more than 0 part by weight and less than or equal to 0.5 part by weight with respect to 100 parts by weight of the positive electrode slurry. Specifically, the content of the dispersant included in the positive electrode slurry may be more than 0.05 part by weight and less than or equal to 0.4 part by weight with respect to 100 parts by weight of the positive electrode slurry.

[0100] According to one embodiment of the present invention, the negative electrode slurry for producing the negative electrode active material layer may include a dispersant, and the dispersant may be a polypyrrolidone-based compound. Specifically, the dispersant may be polyvinylpyrrolidone (Polyvinylpyrrolidone, Junsei, Japan).

[0101] According to one embodiment of the present invention, the content of the dispersant included in the cathode slurry may be more than 0 part by weight and less than or equal to 0.5 part by weight with respect to 100 parts by weight of the cathode slurry. Specifically, the content of the dispersant included in the cathode slurry may be more than 0.05 part by weight and less than or equal to 0.4 part by weight with respect to 100 parts by weight of the cathode slurry.

[0102] According to one embodiment of the present invention, an electrochemical device prepared as described above can be placed in an appropriate case and an electrolyte solution is injected to manufacture a battery.

[0103] According to one embodiment of the present invention, the electrolyte is A + B - As a salt with the same structure as A + is Li + , Na + , K +B containing an ion composed of an alkali metal cation or a combination thereof; - is PF6 - , BF4 - , Cl - , Br - , I - , ClO4 - , AsF6 - , CH3CO2 - , CF3SO3 - , N(CF3SO2)2 - , C(CF2SO2)3 - Salts containing anions such as or combinations thereof are dissolved or dissociated in organic solvents such as propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethyl methyl carbonate (EMC), gamma butyrolactone (γ-butyrolactone) or mixtures thereof, but are not limited thereto.

[0104] One embodiment of the present invention provides a battery module including a battery including the electrochemical element as a unit cell, a battery pack including the battery module, and a device including the battery pack as a power source. Specific examples of the device include, but are not limited to, a power tool that is powered by an electric motor; an electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), etc.; an electric two-wheeled vehicle including an electric bicycle (E-bike) and an electric scooter (E-scooter); an electric golf cart; and a power storage system.

[0105] Hereinafter, the present invention will be described in detail using examples. However, the examples according to the present invention may be modified in various ways, and the scope of the present invention is not limited to the examples described below. The examples in this specification are provided to more fully explain the present invention to those of ordinary skill in the art.

[0106]

[0107] <Example 1>

[0108] Manufacturing of porous polymer substrates

[0109] Polyethylene resin (weight average molecular weight 1 million) was extruded and a porous polymer substrate (total thickness of approximately 9 ㎛, porosity of 60% by volume) was manufactured using a wet method.

[0110]

[0111] Coating layer formation

[0112] Al2O3 powder with a D50 particle size of 500 nm was prepared as an inorganic particle. An acrylic emulsion with a D50 particle size of 200 nm was prepared as a water-soluble polymer, sodium carboxymethyl cellulose (CMC-Na) (SG-L02, GL Chem) was prepared as a dispersant, and a polysiloxane was prepared as a wetting agent.

[0113] The above-prepared inorganic particles, water-soluble polymer, dispersant, and wetting agent were added to water in a weight ratio of 95:4:0.5:0.5, and dispersed to prepare a slurry for a coating layer.

[0114] The slurry for the coating layer was coated on both sides of the porous polymer substrate and dried to form a coating layer each having a thickness of 1.5 μm.

[0115]

[0116] Formation of the first adhesive layer

[0117] PVDF powder with a D50 particle size of 200 nm was prepared as the first polymer binder. Polyacrylic acid and sodium carboxymethyl cellulose (CMC-Na) were prepared as dispersants, and polysiloxane was prepared as a wetting agent.

[0118] The first polymer binder, dispersant, and wetting agent prepared above were added to water and dispersed to prepare a slurry for the first adhesive layer.

[0119] At this time, 100 parts by weight of slurry for the first adhesive layer includes 5 parts by weight of the first polymer binder, 0.5 parts by weight of a dispersant, and 0.5 parts by weight of a wetting agent.

[0120] The slurry for the first adhesive layer was applied to one surface of the above-mentioned manufactured coating layer by a bar coating method, and dried with wind at 50°C using a heat gun to form a first adhesive layer having a thickness of 0.5 μm.

[0121]

[0122] Formation of the second adhesive layer and manufacture of the separator

[0123] A urethane-acrylic copolymer emulsion with a D50 particle size of 200 nm was prepared using a second polymer binder. Polyacrylic acid and sodium carboxymethyl cellulose (CMC-Na) were used as dispersants, and polysiloxane was used as a wetting agent.

[0124] The second polymer binder, dispersant, and wetting agent prepared above were added to water and dispersed to prepare a slurry for the second adhesive layer.

[0125] At this time, 100 parts by weight of slurry for the second adhesive layer includes 5 parts by weight of the first polymer binder, 0.5 parts by weight of a dispersant, and 0.5 parts by weight of a wetting agent.

[0126] The slurry for the second adhesive layer was applied to the other surface of the coating layer on which the first adhesive layer was formed by a bar coating method, and dried with wind at 50°C using a heat gun to form a second adhesive layer with a thickness of 0.5 μm, thereby manufacturing a separator with a total thickness of 13 μm.

[0127]

[0128] <Example 2>

[0129] In the above Example 1, a separator was manufactured in the same manner as in the above Example 1, except that the thickness of each coating layer was 1.0 μm.

[0130]

[0131] <Example 3>

[0132] In the above Example 1, a separator was manufactured in the same manner as in the above Example 1, except that the thickness of each coating layer was 0.5 μm.

[0133]

[0134] <Comparative Example 1>

[0135] In the above Example 1, a separation membrane was manufactured in the same manner as in the above Example 1, except that an acrylic binder having a D50 particle size of 500 nm was used as the second polymer binder.

[0136]

[0137] <Comparative Example 2>

[0138] In the above Example 1, a separation membrane was manufactured in the same manner as in the above Example 1, except that a water-dispersible polyurethane binder having a D50 particle size of 100 nm was used as the second polymer binder.

[0139]

[0140] <Comparative Example 3>

[0141] A separation membrane was manufactured in the same manner as in Example 1, except that a urethane-acrylic copolymer having a D50 particle size of 200 nm was used as the first polymer binder, and a PVDF powder having a D50 particle size of 200 nm was used as the second polymer binder.

[0142]

[0143] Comparative Example 4

[0144] A separation membrane was manufactured in the same manner as in Example 1, except that an acrylic binder having a D50 particle size of 500 nm was used as the first polymer binder, and a PVDF powder having a D50 particle size of 200 nm was used as the second polymer binder.

[0145]

[0146] Comparative Example 5

[0147] In the above Example 1, a separation membrane was manufactured in the same manner as in the above Example 1, except that a water-dispersible polyurethane binder having a D50 particle size of 100 nm was used as the first polymer binder, and PVDF powder having a D50 particle size of 200 nm was used as the second polymer binder.

[0148]

[0149] Comparative Example 6

[0150] In the above Example 1, a separator was manufactured in the same manner as in the above Example 1, except that the thickness of each coating layer was 2.0 μm.

[0151]

[0152] <Comparative Example 7>

[0153] In the above Example 1, a separator was manufactured in the same manner as in the above Example 1, except that a first adhesive layer was formed on one surface of the porous polymer substrate and a second adhesive layer was formed on the other surface of the porous polymer substrate without including a coating layer.

[0154]

[0155] <Manufacturing of electrochemical devices>

[0156] 1) Manufacturing of the anode

[0157] Cathode active material (LiNi) 0.8 Mn 0.1 Co 0.1O2), a conductive agent (carbon black), a dispersant (N-methylpyrrolidone, ADC-01, LG Chemical), and a binder resin (a mixture of PVDF-HFP and PVDF) were mixed with water in a weight ratio of 97.5:0.7:0.14:1.66 to prepare a slurry for a positive electrode active material layer with a concentration of 50 wt% of the remaining components excluding water. Next, the slurry was applied to the surface of an aluminum thin film (thickness 10 μm) and dried to manufacture a positive electrode having a positive electrode active material layer (thickness 120 μm).

[0158] 2) Manufacturing of cathode

[0159] Graphite (natural graphite and artificial graphite blend), conductive agent (carbon black), dispersant (polyvinylpyrrolidone, Junsei, Japan), and binder resin (PVDF-HFP and PVDF blend) were mixed with water in a weight ratio of 97.5:0.7:0.14:1.66 to prepare a slurry for an anode active material layer with a concentration of 50 wt% of the remaining components excluding water. Next, the slurry was applied to the surface of a copper thin film (thickness 10 μm) and dried to manufacture an anode having an anode active material layer (thickness 120 μm).

[0160] 3) Lamination process

[0161] The separators of the above examples and comparative examples were interposed between the manufactured cathodes and anodes, and a lamination process was performed to obtain an electrochemical device. The lamination process was performed using a hot press at 70°C and 5.2 MPa for 10 seconds.

[0162] Figure 2 is a schematic diagram showing a structure in which a separator for an electrochemical device according to one embodiment of the present invention is placed between electrodes.

[0163] According to the above drawing 2, the first adhesive layer (150) is laminated with the separator (100) interposed so that it is in contact with the positive electrode (200) and the second adhesive layer (170) is in contact with the negative electrode (300).

[0164]

[0165] <Experimental Example>

[0166] Membrane-anode adhesion measurement

[0167] The adhesion between the separator and the anode in the above examples and comparative examples was measured using a 180° Peel test using a Universal Testing Machine (UTM). The separator was cut to a width of 2.5 cm and a length of 7 cm, and the anode was cut to a width of 2.5 cm and a length of 6 cm, respectively, and the separator and the anode were placed overlapping each other between imitation paper. After bonding the separator and the anode using a hot press, the bonded separator and the anode were attached to a slide glass with double-sided tape. After attaching a release PET to the separator that is not in contact with the anode, the 180° Peel test was performed by clamping it to a jig. The average value of the adhesion was read, and the unit was gf / 25 mm.

[0168]

[0169] Membrane-cathode adhesion measurement

[0170] The adhesion between the separator and the cathode in the above examples and comparative examples was measured using a 180° Peel test using a Universal Testing Machine (UTM). The separator was cut to a width of 2.5 cm and a length of 7 cm, and the cathode was cut to a width of 2.5 cm and a length of 6 cm, respectively, and the separator and the cathode were then overlapped between imitation paper. After bonding the separator and the cathode using a hot press, the bonded separator and the cathode were attached to a slide glass with double-sided tape. After attaching a release PET to the separator that is not in contact with the cathode, the 180° Peel test was performed by clamping it to a jig. The average value of the adhesion was read, and the unit was gf / 25 mm.

[0171]

[0172] Membrane permeability measurement

[0173] The membrane permeability (permeability, Gurley) of the above examples and comparative examples was measured by the ASTM D726-94 method. The permeability used here is the resistance to air flow, which is measured by a Gurley densometer. The permeability value described here is the value obtained when 100 cc of air passes through 1 in of the membrane under a pressure of 12.2 in H2O. 2 The time (in seconds) it takes to pass through the cross section of the tube is expressed as the ventilation time.

[0174]

[0175] Membrane resistance measurement

[0176] The resistance of the above examples and comparative examples was measured by sandwiching each separator substrate between SUS and injecting electrolyte to manufacture coin cells and measuring the resistance (ER) using the EIS method. At this time, the frequency was in the range of 100,000 to 10,000 Hz. The electrolyte is a non-aqueous solvent containing ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a 3:7 ratio and LiPF6 mixed at a concentration of 1 M.

[0177]

[0178] Measurement of thermal shrinkage (%) of the membrane

[0179] The membranes of the above examples and comparative examples were cut into a size of 50 mm (length) x 50 mm (width) to prepare test pieces, which were then kept in an oven heated to 180°C for 30 minutes, and the specimens were then recovered, and the length changes in the machine direction (MD) and the transverse direction (TD) were measured to calculate the shrinkage ratio of the membrane using the following equation 1.

[0180] [Formula 1]

[0181] Heat shrinkage rate (%) = (length of separator before storage - length of separator after storage) / length of separator after storage

[0182]

[0183]

[0184]

[0185] According to Table 1 above, Examples 1 to 3 selected a fluorine-based polymer binder as the first polymer binder and a urethane-acrylic copolymer as the second polymer binder, thereby ensuring excellent adhesion between the separator and the positive electrode and the separator and the negative electrode, and also improving the air permeability and resistance of the separator.

[0186] In contrast, Comparative Examples 1 and 2 above show that the adhesion between the separator and the positive electrode is excellent by selecting a fluorine-based polymer binder as the first polymer binder, but the adhesion between the separator and the negative electrode is poor.

[0187] In addition, in the case of Comparative Example 3, it can be confirmed that the first polymer binder is the same as the second polymer binder of Example 1, and the second polymer binder is the same as the first polymer binder of Example 1, so that the adhesive strength between the separator and the positive electrode and the separator and the negative electrode are both inferior.

[0188] Similarly, in the case of Comparative Examples 4 and 5, it can be confirmed that the adhesive strength between the separator and the anode and between the separator and the cathode is both poor.

[0189] Furthermore, in the case of Comparative Example 6, the first polymer binder and the second polymer binder were the same as in Example 1, so the adhesive strength between the separator and the positive electrode and the separator and the negative electrode was both excellent, but it could be confirmed that the air permeability and resistance of the separator were greatly increased as the thickness of the coating layer increased.

[0190] Figure 3 is a schematic diagram of a separator for an electrochemical device according to Comparative Example 7 according to one embodiment of the present invention.

[0191] Figure 4 is a schematic diagram showing a structure in which a separator for an electrochemical device of Comparative Example 7 according to one embodiment of the present invention is placed between electrodes.

[0192] Meanwhile, in the case of Comparative Example 7, the first adhesive layer and the second adhesive layer were formed on the porous polymer substrate without including a coating layer, and it can be seen that the thermal shrinkage rate was significantly increased compared to the separator including a coating layer.

[0193] Therefore, the electrochemical device separator according to one embodiment of the present invention and the electrochemical device including the same can improve the adhesive strength with the electrode by including a first adhesive layer and a second adhesive layer on both sides of a porous polymer substrate having a coating layer.

[0194] [Explanation of symbols]

[0195] 100: Separator for electrochemical devices

[0196] 110: Porous polymer substrate

[0197] 130: Coating layer

[0198] 150: First adhesive layer

[0199] 170: Second adhesive layer

[0200] 200: Bipolar

[0201] 300: Cathode

Claims

Porous polymer substrate; A coating layer provided on both sides of the porous polymer substrate and containing inorganic particles; A first adhesive layer including a first polymer binder on one surface of a porous polymer substrate having the above coating layer; and A separator for an electrochemical device, comprising a second adhesive layer including a second polymer binder on the other surface of a porous polymer substrate having the above coating layer. In claim 1, A separator for an electrochemical device, wherein the thickness of the coating layer is less than 2.0 μm. In claim 1, A separator for an electrochemical device, wherein the first polymer binder is different from the second polymer binder. In claim 1, A separator for an electrochemical device, wherein the first polymer binder is a fluorine-based polymer binder. In claim 1, A separator for an electrochemical device, wherein the second polymer binder is a urethane-based polymer binder. In claim 5, A separator for an electrochemical device, wherein the above urethane-based polymer binder is a urethane-acrylic copolymer. In claim 1, A separator for an electrochemical device, wherein the first adhesive layer is formed on the positive electrode orientation surface of the electrochemical device. In claim 1, A separator for an electrochemical device, wherein the second adhesive layer is formed on the cathode-oriented surface of the electrochemical device. In claim 1, A separator for an electrochemical device, wherein the anodic adhesive strength of the first adhesive layer is greater than the anodic adhesive strength of the second adhesive layer. In claim 1, A separator for an electrochemical device, wherein the negative adhesive strength of the second adhesive layer is greater than the negative adhesive strength of the first adhesive layer. An electrochemical device comprising: an anode; a cathode; and a separator interposed between the anode and the cathode, the separator of claim 1.

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