KR20200085233A - Separator, electrochemical device comprising the same and manufacturing method for separator - Google Patents

Abstract

Disclosed are a method for manufacturing a separator for an electrochemical device and a separator manufactured by the same. The method comprises: a step (S1) of applying, to at least one surface of a porous polymer substrate, a slurry for forming a porous coating layer including inorganic particles, a binder polymer, and a solvent for the binder polymer; a step (S2) of immersing the result of the step (S1) in a coagulation solution containing a non-solvent for the binder polymer; and a step (S3) of injecting the result of the step (S2) into a rinse solution and drying the injected result. The temperature of the slurry during the application of the slurry in the step (S1) or the temperature of the coagulating solution during the immersion in the coagulating solution in the step (S2) is controlled to be less than 20°C. The temperature of the slurry during the application of the slurry in the step (S1) or the temperature of the coagulating solution during immersion in the coagulating solution in the step (S2) is controlled to be less, by 5 to 20°C, than the temperature of the rinsing solution when the rinsing solution was input in the step (S3). The present invention can provide the separator in which uniform pores are formed in the porous coating layer and adhesion between electrodes is increased due to the above characteristics, and the method for manufacturing the same.

Description

Separation membrane for electrochemical device, manufacturing method of electrochemical device and separation membrane containing same {SEPARATOR, ELECTROCHEMICAL DEVICE COMPRISING THE SAME AND MANUFACTURING METHOD FOR SEPARATOR}

The present invention relates to a separator for an electrochemical device, an electrochemical device comprising the same, and a method of manufacturing the separator.

Recently, interest in energy storage technology has been increasing. As the field of application extends to the energy of mobile phones, camcorders, notebook PCs, and even electric vehicles, efforts for research and development of electrochemical devices are becoming more concrete. The electrochemical device is the most attracting field in this aspect, and among them, the development of a secondary battery capable of charging and discharging has become a focus of interest, and recently, in developing such a battery, a new electrode to improve capacity density and specific energy. Research and development are being conducted on the design of the over battery.

Among the currently applied secondary batteries, lithium secondary batteries developed in the early 1990s have the advantage of higher operating voltage and higher energy density than conventional batteries such as Ni-MH, Ni-Cd, and sulfuric acid-lead batteries using aqueous electrolyte solutions. Is in the limelight.

Electrochemical devices such as lithium secondary batteries are produced by many companies, but their safety characteristics show different aspects. It is very important to evaluate the safety and safety of these electrochemical devices. The most important consideration is that the electrochemical device should not cause injury to the user in case of malfunction. For this purpose, the safety standard strictly regulates ignition and smoke in the electrochemical device. In the safety characteristics of the electrochemical device, there is a high possibility that an electrochemical device will overheat and cause a thermal runaway or an explosion if the separator penetrates. In particular, a polyolefin-based porous polymer substrate commonly used as a separator for an electrochemical device exhibits extreme heat shrinkage behavior at a temperature of 100° C. or higher due to material properties and manufacturing process characteristics, including stretching, between an anode and a cathode. It caused a short circuit.

In order to solve the safety problem of the electrochemical device, a separator having a porous coating layer has been proposed by coating a mixture of excess inorganic particles and a binder polymer on at least one surface of a porous polymer substrate having multiple pores.

Meanwhile, the porous coating layer can make pores through immersion phase separation. At this time, if the phase separation kinetics is too fast, most of the binder polymer has a problem of forming large pores on the surface of the porous coating layer, and there is a problem of poor adhesion between the porous polymer substrate and the porous coating layer. On the other hand, if the phase separation kinetics is too slow, most of the binder polymers have small pores on the bottom surface of the porous coating layer or are formed without pore structures, and there is a problem that an adhesive layer with an electrode is not formed.

Therefore, the problem to be solved by the present invention is to solve the above-mentioned problems, to form a uniform pore in the porous coating layer, to improve the adhesion to the electrode and to provide a separation membrane and a method of manufacturing the same.

Another problem to be solved by the present invention is to provide an electrochemical device having the separator.

One aspect of the present invention provides a method of manufacturing a separator for an electrochemical device according to the following embodiments.

The first embodiment,

(S1) applying a slurry for forming a porous coating layer comprising inorganic particles, a binder polymer, and a solvent for the binder polymer on at least one surface of the porous polymer substrate; (S2) immersing the result of the step (S1) in a coagulating solution containing a non-solvent for the binder polymer; And (S3) adding and drying the result of the step (S2) in the rinse solution, the temperature of the slurry when applying the slurry in the step (S1) and/or the immersion in the coagulation solution in the step (S2). The temperature of the solid liquid is controlled to be less than 20°C, and the temperature of the slurry when the slurry is applied in the step (S1) and/or the temperature of the solidified liquid when the solid solution is immersed in the step (S2), the rinse liquid in the step (S3) It relates to a method of manufacturing a separator for an electrochemical device, which is controlled to be 5 to 25°C lower than the temperature of the rinse solution at the time of injection.

The second embodiment, in the first embodiment,

In the method of manufacturing a separation membrane for an electrochemical device, the temperature of the slurry when the slurry is applied in the step (S1) and/or the temperature of the coagulation liquid when the coagulant is immersed in the step (S2) is 5 to 20°C. It is about.

The third embodiment, in the first or second embodiment,

The temperature difference between the temperature of the slurry when the slurry is applied in the step (S1) and/or the temperature of the coagulation liquid when the coagulant is immersed in the step (S2) and the temperature of the rinse liquid when the rinse liquid is added in the step (S3) is 15°C. It relates to a method of manufacturing a separator for an electrochemical device, which is controlled to 25°C.

The fourth embodiment, in any one of the first to third embodiments,

The solvent is capable of dissolving 10 wt% or more of the binder polymer at 25° C., and includes at least one selected from N-methyl-2-pyrrolidone, dimethylacetamide, and dimethylformamide. It relates to a method for manufacturing a separation membrane.

The fifth embodiment, in any one of the first to fourth embodiments,

The non-solvent is capable of dissolving less than 5wt% of the binder polymer at 25°C, and includes one or more selected from water, methanol, ethanol, propyl alcohol, butyl alcohol, butanediol, ethylene glycol, propylene glycol, and tripropylene glycol. That is, it relates to a method of manufacturing a separator for an electrochemical device.

The sixth embodiment, in any one of the first to fifth embodiments,

The coagulation solution relates to a method of manufacturing a separator for an electrochemical device, wherein the content of the non-solvent is 100 wt% or more in 100 wt% of the coagulation solution.

The seventh embodiment according to any one of the first to sixth embodiments,

The rinse liquid contains a non-solvent, and the content of the non-solvent in 100 wt% of the rinse liquid is 90 wt% or more, and relates to a method of manufacturing a separator for an electrochemical device.

The eighth embodiment according to any one of the first to seventh embodiments,

The step (S3) is a method of preparing a separator for an electrochemical device, in which a plurality of rinsing liquids are prepared, and the result of the step (S2) is sequentially immersed in each rinsing liquid for a predetermined time. It is about.

The ninth embodiment, in the eighth embodiment,

The temperature of the first rinse liquid among the plurality of rinse liquids is controlled to a temperature higher than the temperature of the coagulating liquid when the coagulant is immersed, and the temperature of the last rinse liquid is controlled to a temperature lower than the drying temperature. It relates to a method of manufacturing a separator.

In the tenth embodiment, in the eighth or ninth embodiment,

The plurality of rinsing liquids relates to a method of manufacturing a separator for an electrochemical device, in which the temperature of the rinsing liquid is sequentially increased from the initial rinsing liquid to the last rinsing liquid.

The eleventh embodiment according to any one of the first to tenth embodiments,

After the step (S3), it further relates to a method of manufacturing a separation membrane for an electrochemical device, which further includes the step (S4) of annealing the result of the step (S3) in an annealing tank.

The twelfth embodiment according to any one of the first to eleventh embodiments,

The porous polymer substrate includes a thermoplastic resin having a melting temperature of less than 200°C, a thickness of 4 μm to 15 μm, and a porosity of 30% to 70%, which relates to a method of manufacturing a separator for an electrochemical device.

The thirteenth embodiment is any one of the first to twelfth embodiments,

The thickness of the porous coating layer is 1.5 µm to 4.0 µm, and the filling density of the porous coating layer is 1 g/cc to 1.5 g/cc, and relates to a method of manufacturing a separator for an electrochemical device.

The fourteenth embodiment according to any one of the first to thirteenth embodiments,

The inorganic particles do not undergo oxidation and/or reduction reactions in the operating voltage range (0 to 5 V based on Li/Li+) of the electrochemical device, and the average particle diameter (D50) of the particles is 0.1 μm to 2.5 μm, It relates to a method of manufacturing a separator for an electrochemical device.

The fifteenth embodiment is any one of the first to fourteenth embodiments,

The binder polymer is polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyvinylidene fluoride-trifluoro Propylene (polyvinylidene fluoride-co-trifluoropropylene), polyvinylidene fluoride-co-tetrafluoropropylene, polymethylmethacrylate, polyethylhexyl acrylate, polybutyl Copolymer of acrylate (polybutylacrylate), polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylhexyl acrylate and methyl methacrylate , Ethylene vinyl acetate copolymer, poly(ethylene oxide), polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate Cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, plurlan, carboxyl Methyl cellulose thyl cellulose), or a mixture of two or more of them, relates to a method of manufacturing a separator for an electrochemical device.

The 16th embodiment according to any one of the 1st to 15th embodiments,

The weight ratio of the inorganic particles and the binder polymer is 20:80 to 95:5, and relates to a method of manufacturing a separator for an electrochemical device.

Another aspect of the present invention provides a separator for an electrochemical device according to the following embodiments.

Embodiment 17,

Obtained according to the method of any one of the first to sixteenth embodiments,

A separator comprising a porous polymer substrate and a porous coating layer formed on at least one surface of the porous polymer substrate,

Here, the porous coating layer includes inorganic particles and a binder polymer,

The porous coating layer includes at least one node including a binder polymer covering at least a portion of the inorganic particles and the surface of the inorganic particle and at least one filament formed in a thread shape from the binder polymer of the node, , It relates to a separator for an electrochemical device, wherein one or more filaments extending from one node are formed, and the filaments are arranged in a way to connect one node to another node.

The 18th embodiment is the 17th embodiment,

The porous coating layer has a thickness of 2 μm to 4 μm, and the filling density of the porous coating layer is 1 g/cc to 1.5 g/cc, which relates to a separator for an electrochemical device.

Another aspect of the present invention provides an electrochemical device according to the following embodiment.

Embodiment 19,

In the electrochemical device comprising an anode, a cathode, and a separator interposed between the anode and the cathode,

The separator is an electrochemical device, which is the separator for an electrochemical device described in the 17th embodiment.

According to an embodiment of the present invention, by controlling the temperature at the time of applying the slurry for forming the porous coating layer, the temperature of the coagulating liquid, and the temperature of the rinsing liquid, forming uniform pores in the porous coating layer, improving the adhesion between the electrodes, At the same time, it is possible to provide a separator having the same or similar resistance as a conventional separator and a method for manufacturing the same.

1 to 3 are SEM images showing the shapes of the porous coating layers according to Examples 1 to 3 of the present invention, respectively.
Figure 4 is a SEM image showing the shape of the porous coating layer according to Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in detail. The terms or words used in the specification and claims should not be interpreted as being limited to ordinary or dictionary meanings, and the inventor can appropriately define the concept of terms in order to best describe his or her invention. Based on the principle of being present, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

Throughout the present specification, when a part is "connected" to another part, this includes not only "directly connected" but also "indirectly connected" with another member in between. . In addition, the connection implies an electrochemical connection as well as a physical connection.

Throughout the present specification, when a part “includes” a certain component, it means that the component may further include other components, not to exclude other components, unless otherwise stated.

Also, when used herein, "comprise" and/or "comprising" specifies the shapes, numbers, steps, actions, elements, elements and/or the existence of these groups. And does not exclude the presence or addition of one or more other shapes, numbers, actions, elements, elements and/or groups.

The terms "about", "substantially", and the like used throughout this specification are used as or in close proximity to the numerical values when manufacturing and material tolerances specific to the stated meaning are given, and are used to aid in understanding of the present application. Or an absolute value is used to prevent unconscionable exploitation of the disclosed content by unscrupulous intruders.

Throughout the present specification, the term "the combination(s)" included on the surface of the marki form means one or more mixtures or combinations selected from the group consisting of elements described in the expression of the marki form, It means to include one or more selected from the group consisting of the above components.

Throughout this specification, the description of "A and/or B" means "A or B or both".

Method of manufacturing a separator for an electrochemical device according to an aspect of the present invention,

(S1) applying a slurry for forming a porous coating layer comprising inorganic particles, a binder polymer and a solvent for the binder polymer on at least one surface of the porous substrate;

(S2) immersing the result of the step (S1) in a coagulating solution containing a non-solvent for the binder polymer; And

(S3) the step of introducing the result of the step (S2) into the rinse solution,

At least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulating solution is immersed in the step (S2) is controlled to less than 20°C,

At least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulant is immersed in the step (S2) is 5 than the temperature of the rinse solution when the rinse solution is added in the step (S3). It is controlled so that it is low to 25°C.

Hereinafter, each step will be described in detail.

First, a slurry for forming a porous coating layer containing inorganic particles, a binder polymer, and a solvent for a binder polymer is applied to at least one surface of the porous polymer substrate (S1).

Specifically, a binder polymer is dissolved in a solvent, and inorganic particles are dispersed to prepare a slurry for forming a porous coating layer. Thereafter, the slurry for forming the porous coating layer is applied on at least one surface of a planar porous polymer substrate having a plurality of pores. The slurry may be applied by a conventional coating method in the technical field of the present invention, such as a Meyer bar, a die coater, a reverse roll coater, or a gravure coater. When the porous coating layer is formed on both sides of the porous polymer substrate, it is also possible to coagulate, wash and dry the coating solution one by one, but coagulate, wash and dry the coating solution on both sides of the porous polymer substrate simultaneously. It is preferable from the viewpoint of productivity.

In the present invention, the solvent of the slurry for forming the porous coating layer is to dissolve the binder polymer, and specifically means to dissolve 10 Wt% or more of the binder polymer at 25°C.

In one specific embodiment of the present invention, the solvent may include one or more selected from N-methyl-2-pyrrolidone, dimethylacetamide and dimethylformamide.

In one specific embodiment of the present invention, the binder polymer may be a polymer commonly used in the art to form a porous coating layer. In particular, a polymer having a glass transition temperature (Tg) of -200 to 200°C may be used, because mechanical properties such as flexibility and elasticity of the finally formed porous coating layer can be improved. These binder polymers faithfully perform the role of a binder that connects and stably fixes the inorganic particles, thereby contributing to the prevention of deterioration in mechanical properties of the separator in which the porous coating layer is introduced.

In addition, the binder polymer does not necessarily have an ion conducting ability, but when using a polymer having an ion conducting ability, the performance of the electrochemical device can be further improved. Therefore, as the binder polymer, one having a high dielectric constant is possible. In fact, since the degree of dissociation of a salt in an electrolyte solution depends on the dielectric constant of the electrolyte solvent, the higher the dielectric constant of the binder polymer, the better the salt dissociation in the electrolyte. The dielectric constant of the binder polymer may be in the range of 1.0 to 100 (measurement frequency = 1 kHz), and may be 10 or more.

In addition to the above-described functions, the binder polymer may have a characteristic that can exhibit a high degree of swelling of the electrolyte by being gelled upon impregnation of the liquid electrolyte. Accordingly, the solubility index of the binder polymer, that is, the Hildebrand solubility parameter (Hildebrand solubility parameter) is in the range of 15 to 45 MPa ^1/2 or 15 to 25 MPa ^1/2 and 30 to 45 MPa ^1/2 . Therefore, hydrophilic polymers having many polar groups may be used more than hydrophobic polymers such as polyolefins. This is because when the solubility index is less than 15 MPa ^{1/2 and more} than 45 MPa ^1/2 , it may be difficult to swell with a conventional battery liquid electrolyte.

In one specific embodiment of the present invention, the binder polymer is polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene , Polyvinylidene fluoride-co-trifluoropropylene, polyvinylidene fluoride-co-tetrafluoropropylene, polymethylmethacrylate, polyethyl Hexylacrylate (polyetylexyl acrylate), polybutylacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylhexyl acrylate and methyl Copolymer of methacrylate, ethylene-vinyl acetate copolymer, polyethylene oxide, polyarylate, cellulose acetate, cellulose acetate butylate (cellulose acetate butyrate), cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose ), Plululan, Kar Carboxyl methyl cellulose or a mixture of two or more of them.

In one specific embodiment of the present invention, the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as they do not undergo oxidation and/or reduction reactions in the operating voltage range of the applied electrochemical device (for example, 0 to 5 V based on Li/Li ⁺ ). Particularly, when inorganic particles having a high dielectric constant are used as the inorganic particles, ionic conductivity of the electrolyte may be improved by contributing to an increase in dissociation of electrolyte salts, such as lithium salts, in the liquid electrolyte.

For the aforementioned reasons, it is preferable that the inorganic particles include high dielectric constant inorganic particles having a dielectric constant of 5 or more, preferably 10 or more. Non-limiting examples of inorganic particles having a dielectric constant of 5 or more include BaTiO ₃ , Pb(Zr,Ti)O ₃ (PZT), Pb _1-x La _x Zr _1-y Ti _y O ₃ (PLZT, 0<x<1 , 0<y<1), Pb(Mg _1/3 Nb _2/3 )O ₃ -PbTiO ₃ (PMN-PT), hafnia (HfO ₂ ), SrTiO ₃ , SnO ₂ , CeO ₂ , MgO, NiO, CaO, ZnO, ZrO ₂ , SiO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , AlOOH, SiC and TiO ₂ or mixtures thereof.

In addition, as the inorganic particles, inorganic particles having lithium ion transfer ability, that is, inorganic particles containing lithium elements but having the function of moving lithium ions without storing lithium may be used. Non-limiting examples of inorganic particles having a lithium ion transfer ability are lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y <3), Lithium aluminum titanium phosphate (Li _x Al _y Ti _z (PO ₄ ) ₃ , 0 <x <2, 0 <y <1, 0 <z <3), 14Li ₂ O-9Al ₂ O ₃ -38TiO ₂ -39P ₂ (LiAlTiP)xOy-based glass such as O ₅ (0 <x <4, 0 <y <13), lithium lanthanitanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), Li Lithium germanium thiophosphate (Li _x Ge _y P _z S _w , 0 <x <4, 0 <y <1, 0 <z <1, 0 <w <5), such as _3.25 Ge _0.25 P _0.75 S ₄ Lithium nitride (Li _x N _y , 0 <x <4, 0 <y <2), such as Li ₃ N, SiS ₂ series glass (Li _x Si _y S, such as Li ₃ PO ₄ -Li ₂ S-SiS ₂₎ P ₂ S ₅ series glass (Li _x P _y S _z , 0 <x <3) such as _z , 0 <x <3, 0 <y <2, 0 <z <4), LiI-Li ₂ SP ₂ S _5, etc. , 0< y <3, 0 <z <7) or mixtures thereof.

In addition, the diameter of the inorganic particles is not particularly limited, but for the formation of a porous coating layer of uniform thickness and proper porosity, it is preferable to be in the range of 0.1 μm to 1.5 μm. If it is less than 0.1 μm, dispersibility may decrease, and when it exceeds 1.5 μm, the thickness of the coating layer formed may increase.

In one specific embodiment of the present invention, the weight ratio of the inorganic particles and the binder polymer is, for example, 20:80 to 95:5, and specifically 70:30 to 95:5. When the content ratio of the inorganic particles to the binder polymer satisfies the above range, the problem of reducing the pore size and porosity of the porous coating layer formed by increasing the content of the binder polymer can be prevented, and the binder polymer content is small. The problem that the peeling resistance of the formed porous coating layer is weakened can also be solved.

The separator according to an aspect of the present invention may further include other additives in addition to the above-described inorganic particles and polymers as a porous coating layer component.

In one specific embodiment of the present invention, the thickness of the porous coating layer is preferably 1.5㎛ to 4.0㎛, or 2㎛ to 4㎛. In order to secure the safety of the separator, it is advantageous to include as many inorganic particles as possible in the porous coating layer. In the present invention, since the thickness of the porous coating layer is thin even though the same amount of inorganic particles is included, the filling density of the porous coating layer may be formed. Accordingly, the energy density of the battery may be improved as compared with the case where the porous coating layer has a thick thickness while having the same amount of inorganic particles.

In one specific embodiment of the present invention, the filling density of the porous coating layer may be 1 g/cc to 1.5 g/cc. The filling density can be calculated by dividing the coating amount (g/m ² ) of the slurry for forming the coated porous coating layer per unit area by the thickness (µm) of the pure porous coating layer excluding the thickness of the porous polymer substrate from the total thickness of the separator. It can be estimated from the filling density whether the porous coating layer has uniform pores. Specifically, the filling density indicates the application amount of the coating layer applied to a certain thickness, and when the filling density is high, it has uniform pores, and when the filling density is low, it is highly likely to have uneven pores.

In one specific embodiment of the present invention, the porous polymer substrate refers to a substrate having a plurality of pores formed therein as an ion conductive barrier that passes ions while blocking electrical contact between the positive electrode and the negative electrode. do. The pores are structured to be interconnected with each other, so that gas or liquid can pass from one side of the substrate to the other.

As the material constituting such a porous polymer substrate, either an organic material or an inorganic material having electrical insulation properties can be used. In particular, from the viewpoint of providing a shutdown function to the substrate, it is preferable to use a thermoplastic resin as a constituent material of the substrate. Here, the shutdown function refers to a function that prevents thermal runaway of the battery by blocking the movement of ions by melting the thermoplastic resin and closing the pores of the porous substrate when the battery temperature increases. As the thermoplastic resin, a thermoplastic resin having a melting point of less than 200°C is suitable, and particularly polyolefins, such as polyethylene, are preferred.

In addition, polymer resins such as polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, and polyethylene naphthalene. It may further include at least one of. The porous polymer substrate includes a nonwoven fabric or a porous polymer film, or a laminate of two or more of them, but is not particularly limited thereto.

Specifically, the porous polymer substrate is one of a) to e) below.

a) a porous film formed by melting/extruding a polymer resin,

b) a multilayer film in which two or more layers of the porous film of a) are laminated,

c) a nonwoven web produced by integrating filaments obtained by melting/spinning a polymer resin,

d) a multi-layer film in which two or more layers of the nonwoven web of b) are laminated

e) A porous composite membrane having a multi-layer structure comprising two or more of a) to d).

In the present invention, the porous polymer substrate is preferably 3㎛ to 15㎛ or 4㎛ to 15㎛, or 5㎛ to 12㎛ thickness. If the thickness does not reach the above value, the function of the conductive barrier is not sufficient, whereas when the range is excessively exceeded (ie, too thick), the resistance of the separator may be excessively increased.

In one embodiment of the present invention, the weight average molecular weight of the polyolefin is preferably 100,000 to 5 million. When the weight average molecular weight is less than 100,000, it may be difficult to secure sufficient mechanical properties. Moreover, when it is larger than 5 million, shutdown characteristics may be deteriorated or molding may be difficult. Further, the protruding strength of the porous polymer substrate may be 300 gf or more from the viewpoint of improving production yield. The puncture strength of the porous polymer substrate refers to the maximum puncture load (gf) measured by performing a puncture test under conditions of a radius of curvature of 0.5 mm at the tip of the needle and a puncture speed of 2 mm/sec using a Kato tech KES-G5 Handy Compression Tester.

In one specific embodiment of the present invention, the porous polymer substrate can be used as long as it is a planar porous polymer substrate used in an electrochemical device, for example, having high ion permeability and mechanical strength, and the pore diameter is generally 10 nm to It may be 100nm.

In one specific embodiment of the present invention, the porous polymer substrate includes a thermoplastic resin having a melting temperature of less than 200°C, a thickness of 4 μm to 15 μm, and a porosity of 30% to 70%.

In one specific embodiment of the present invention, the porous polymer substrate may be a polyolefin-based porous polymer substrate.

Thereafter, the result of the step (S1) is immersed in a coagulating solution containing a non-solvent for the binder polymer (S2).

In the present invention, a non-solvent is one capable of dissolving less than 5 wt% of the binder polymer at 25°C. That is, it means a solvent that does not dissolve the above-described binder polymer, and is not particularly proposed if it is a liquid compatible with the solvent used to facilitate phase separation.

In one specific embodiment of the present invention, the non-solvent may include one or more selected from water, methanol, ethanol, propyl alcohol, butyl alcohol, butanediol, ethylene glycol, propylene glycol, and tripropylene glycol.

In addition, if the phase separation behavior in the step of immersing in a coagulation solution containing a non-solvent is too rapid, the phase separation rate may be controlled by mixing some solvents. Specifically, the phase separation occurs as a non-solvent is input, and the higher the non-solvent content, the faster the phase separation kinetics.

Accordingly, in one specific embodiment of the present invention, the coagulation solution may have a non-solvent content of 100 wt% or more, 60 wt% or more, 70 wt% or more, or 80 wt% or more. Thus, by controlling the content of the non-solvent, while maintaining the adhesive strength between the porous polymer substrate and the porous coating layer above a certain value, it is possible to provide a separator having a low resistance value.

The non-solvent promotes phase separation of the binder polymer in the slurry for forming the porous coating layer, so that the binder polymer is more present on the surface of the porous coating layer. Accordingly, after the drying treatment to be described later, the binding property of the separator to the electrode is increased, so that the lamination becomes easy.

Meanwhile, in one embodiment of the present invention, the immersion may be controlled to 30 to 100 seconds, or 40 to 90 seconds. When the immersion time satisfies this range, the phase separation occurs excessively and the adhesion between the porous polymer substrate and the porous coating layer is lowered, thereby preventing the problem of detachment of the coating layer and forming uniform pores in the thickness direction. have.

Next, the step of introducing and drying the resultant of the step (S2) into the rinse solution (S3).

In one specific embodiment of the present invention, the rinse liquid is for removing residual solvent in the produced separator.

In one specific embodiment of the present invention, the rinse liquid may include a non-solvent. However, as time passes, as some solvents removed from the separator remain in the rinse liquid, the non-solvent and the residual solvent may be mixed.

Accordingly, the rinse liquid contains a non-solvent, and the content of the non-solvent in 100 wt% of the rinse liquid may be 90 wt% or more.

In one specific embodiment of the present invention, it is preferable that the rinse liquid is designed in multiple stages so that the amount of the solvent remaining in the rinse liquid can be reduced toward the rear stage.

On the other hand, the method of manufacturing the separation membrane for an electrochemical device according to an aspect of the present invention, at least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when immersed in the step (S2) Is controlled to be less than 20° C., and at least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulant is immersed in the step (S2), the rinse solution in the step (S3) is introduced It is controlled so that it is 5 to 25 degreeC lower than the temperature of the rinse liquid of the city.

In a specific embodiment of the present invention, at least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulating solution is immersed in the step (S2) is 5°C or more to less than 20°C, Or it can be controlled to 7 ℃ to 19 ℃ or 8 ℃ to 17 ℃. At temperatures lower than this, non-solvent condensation occurs, which is undesirable, and at higher temperatures, phase separation occurs rapidly and the coating layer structure is not dense, so that a porous coating layer composed of the node and the filament intended in the present invention is not formed and the binder in some areas It has an excessively dense structure, which is undesirable for realizing resistance characteristics and adhesion.

In addition, in a specific embodiment of the present invention, at least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulating solution is immersed in the step (S2), and the step (S3) The temperature difference of the rinse liquid when the rinse liquid is injected can be controlled to 5°C to 25°C, or 6°C to 23°C, or 8°C to 10°C.

That is, in the present invention, the temperature of the slurry and/or the temperature of the coagulating liquid during immersion is controlled to be lower than the temperature of the rinse liquid.

When the temperature is controlled as described above, the phase separation kinetics is slowed to produce a dense structure in the porous coating layer desired in the present invention.

In one specific embodiment of the present invention, the step (S3) may be performed in a manner of preparing two or more rinsing liquids, and sequentially immersing the result of the step (S2) in each rinsing liquid for a predetermined time. have. When designing a plurality of rinse liquids, the rinse liquid containing non-solvent can be reduced from being contaminated by the solvent removed from the separation membrane.

In a specific embodiment of the present invention, when preparing a plurality of rinse liquid, the temperature of the first rinse liquid when the separator is first introduced is controlled to a temperature higher than the temperature of the coagulant when the coagulant is immersed, The temperature of the rinse liquid at the time of the last rinse liquid injection can be controlled to a temperature lower than that of the drying furnace.

Specifically, when a plurality of rinse liquids are prepared, the temperature of the first rinse liquid when the separator is first introduced is controlled to a temperature of 5 to 25° C. higher than the temperature of the coagulant when immersed in the coagulant, and the final rinse liquid The temperature of the rinse liquid at the time of injection can be controlled to a temperature lower than that of the drying furnace by 20 to 80°C.

In a specific embodiment of the present invention, when preparing a plurality of rinse liquid, it is preferable to sequentially increase the temperature of the rinse liquid from the initial rinse liquid to the last rinse liquid.

Meanwhile, in one embodiment of the present invention, the immersion may be controlled to 30 to 100 seconds, or 40 to 90 seconds. When the immersion time satisfies this range, the phase separation occurs excessively and the adhesion between the porous polymer substrate and the porous coating layer is lowered, thereby preventing the problem of detachment of the coating layer and forming uniform pores in the thickness direction. have.

In one specific embodiment of the present invention, after the step (S3), the step of (S4) for annealing the result of the step (S3) in an annealing tank may be further included.

Thereafter, by drying the resultant input to the rinse solution, a porous coating layer may be formed on at least one side of the porous polymer substrate.

At this time, the solvent contained in the slurry of the porous coating layer is removed in the rinse step, and in the drying step, the non-solvent may be removed.

The drying may be performed in a drying chamber, in which case the conditions of the drying chamber are not particularly limited due to non-solvent application. As a result, the surface portion of the porous coating layer contains more binder polymer than the lower portion thereof, so that the binding strength to the above-described electrode is excellent, and the porous coating layer is formed to have the same height as a whole despite the portion showing the electrode adhesion. It has the same resistance in the plane direction.

An electrochemical device may be manufactured by laminating the separator prepared according to the above-described method between the anode and the cathode. Electrochemical devices include all devices that undergo an electrochemical reaction, and specific examples include capacitors such as all types of primary, secondary cells, fuel cells, solar cells, or super capacitor devices. In particular, a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery is preferable among the secondary batteries.

The electrodes of the positive electrode and the negative electrode to be applied together with the separator of the present invention are not particularly limited, and may be manufactured in a form in which an electrode active material is attached to at least one surface of an electrode current collector according to a conventional method known in the art.

As a non-limiting example of the positive electrode active material among the electrode active materials, a conventional positive electrode active material that can be used for the positive electrode of a conventional electrochemical device can be used, in particular lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, or combinations thereof. It is preferable to use one lithium composite oxide.

As a non-limiting example of the negative electrode active material, a conventional negative electrode active material that can be used for the negative electrode of a conventional electrochemical device can be used, in particular lithium metal or lithium alloy, carbon, petroleum coke, activated carbon, Lithium adsorbents such as graphite or other carbons are preferred.

Non-limiting examples of the positive electrode current collector include foil made of aluminum, nickel, or a combination thereof, and non-limiting examples of the negative electrode current collector are copper, gold, nickel or copper alloy, or combinations thereof. Foil, etc.

Electrolyte that may be used in the electrochemical device of the present invention is A ⁺ B ^- A salt of the structure, such as, A ⁺ comprises a Li ^+, Na ^+, an alkali metal cation or an ion composed of a combination thereof, such as K ⁺ B ^- is _{^{PF 6 -, BF 4 -,}} Cl -, Br -, I -, ClO 4 -, AsF 6 -, CH 3 CO 2 -, CF 3 SO 3 -, N (CF 3 SO 2) 2 -, C (CF ₂ SO _{2) 3} ^- anion, or a salt containing an ion composed of a combination of propylene carbonate (PC) such as, ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl Carbonate (DPC), dimethylsulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethylcarbonate (EMC), gamma butyrolactone or these Dissolved or dissociated in an organic solvent consisting of a mixture of, but is not limited to this.

The electrolyte injection may be performed at an appropriate step in the battery manufacturing process, depending on the final product manufacturing process and required physical properties. That is, it may be applied before battery assembly or at the final stage of battery assembly.

On the other hand, another aspect of the present invention is obtained according to the above-described method,

A separator comprising a porous polymer substrate and a porous coating layer formed on at least one surface of the porous polymer substrate,

Here, the porous coating layer includes inorganic particles and a binder polymer,

The porous coating layer includes at least one node including a binder polymer covering at least a portion of the inorganic particles and the surface of the inorganic particles and at least one filament formed in a thread shape from the binder polymer of the node, , One or more filaments extending from one node are formed, and the filaments are disposed in a manner of connecting one node to another node, thereby providing a separator for an electrochemical device.

In the present invention, the separator is composed of a porous coating layer formed on one surface of the porous polymer substrate. The porous coating layer includes inorganic particles and a binder polymer.

Specifically, the porous coating layer includes inorganic particles and a binder polymer positioned on a part or all of the surface of the inorganic particles to connect and fix the particles between the inorganic particles.

In addition, the porous coating layer is filled with at least one or more particles selected from among the inorganic particles by the binder polymer and connected to each other, thereby forming an interstitial volume between the binder polymer and the particles. , The interstitial volume between the binder polymer and the particles becomes an empty space to have pores formed.

In one embodiment of the present invention, the inorganic particles are all or at least partially coated on the surface by the particulate binder polymer and are surface-bonded and/or point-bonded via the binder polymer.

In one embodiment of the present invention, the average pore size of the porous coating layer is 20nm to 1,000nm. Within the above range, the average pore size of the porous coating layer may be 800 nm or less, or 500 nm or less, and independently or together, may be 20 nm or more, 50 nm or more, or 100 nm or more. For example, the average pore size of the porous coating layer is 20nm to 800nm. The size of the pores can be calculated from shape analysis through SEM images. When the size of the pores is smaller than the above range, the pores are likely to be blocked due to the expansion of the particulate binder polymer in the coating layer, and when the size of the pores is outside the above range, the function as an insulating film is difficult, and the self-discharge characteristics after the production of the secondary battery deteriorate. there is a problem.

In one embodiment of the present invention, the porosity of the porous coating layer is preferably 30% to 80%. When the porosity is 30% or more, it is advantageous in terms of permeability of lithium ions, and when the porosity is 80% or less, the surface opening ratio is not too high, which is suitable for securing adhesion between the separator and the electrode.

On the other hand, in the present invention, the porosity and the size of the pores are measured using a BELSORP (BET equipment) of BEL JAPAN using adsorption gas such as nitrogen or mercury intrusion porosimetry or capillary flow measurement method ( capillary flow porosimetry). Alternatively, in one embodiment of the present invention, porosity can be calculated from the theoretical density of the coating layer by measuring the thickness and weight of the obtained coating layer.

The thickness of the porous coating layer is preferably 1.5 μm to 4.0 μm on one side of the porous polymer substrate. Within the above numerical range, the adhesive strength with the electrode is excellent, and as a result, the cell strength of the battery is increased, which is advantageous in terms of the cycle characteristics and resistance characteristics of the battery.

Hereinafter, examples will be described in detail to specifically describe the present invention. However, the embodiments according to the present invention can be modified in many different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

Example 1

1) Cathode production

Artificial graphite as a negative electrode active material, carbon black as a conductive material, carboxymethyl cellulose as a dispersing agent, and a mixture of styrene butadiene rubber and an acrylic copolymer (Zeon, BM-L301) as a binder polymer in a weight ratio of 95.8:1:1.2:2 And mixed to prepare a negative electrode slurry. The prepared negative electrode slurry was coated on a copper foil (Cu-foil) to a thickness of 50 μm to form a thin electrode plate, dried at 135° C. for 3 hours or more, and then pressed to prepare a negative electrode.

2) Anode manufacturing

A positive electrode slurry was prepared by mixing LiCoO ₂ as a positive electrode active material, carbon black as a conductive material, and polyvinylidene fluoride as a binder polymer with N-methyl-2-pyrrolidone (NMP) in a weight ratio of 97.0:1.5:1.5, respectively. . The prepared positive electrode slurry was coated on a 20 μm thick aluminum foil as a positive electrode current collector with a capacity of 3.1 mAh/cm 2 to prepare a positive electrode.

3) Preparation of separator

Al ₂ O ₃ (Sumitomo, AES11) is dispersed as an inorganic particle in a solvent N-methyl-2-pyrrolidone, and polyvinylidene fluoride-hexafluoropropylene (Solvay, Solef 21510) is dissolved as a binder polymer. To prepare a slurry for forming a porous coating layer. At this time, the weight ratio of the inorganic particles and the binder polymer was 65:35. The prepared slurry for forming a porous coating layer was applied to one surface of a 9 μm thick polyethylene-based porous polymer substrate (W scope, WL11B, aeration time 150 seconds/100 cc) using a doctor blade. The temperature of the slurry when applying the slurry was 15°C.

Thereafter, the resultant was immersed in a coagulating solution containing non-solvent water. At this time, the temperature of the coagulating liquid was room temperature (25°C). In addition, the weight ratio of N-methyl-2-pyrrolidone and water in the coagulation solution was 1:9. Then, the resultant was sequentially added to rinse solutions 1 to 3 containing water as a non-solvent. At this time, the temperature of the rinse liquid was room temperature (25°C), and the total residence time in the coagulating liquid and the rinse liquid was 105 seconds. Thereafter, a drying process was performed at a temperature of 75° C. using an oven as a drying furnace to finally prepare a separator for an electrochemical device.

4) Preparation of lithium secondary battery

A unit cell was manufactured by laminating with a 100 kgf load at 80° C. by interposing a separator between the positive electrode and the negative electrode prepared above. After inserting this into the pouch, 1M of LiPF ₆ was injected with an organic electrolyte dissolved in a 3/5/2 (volume ratio) mixed solvent of ethylene carbonate (EC)/ethyl methyl carbonate (EMC)/diethylene carbonate (DEC), respectively. After the pouch was vacuum sealed, the lithium secondary battery was completed through an activation process.

Example 2

A lithium secondary battery was manufactured in the same manner as in Example 1, except that the temperature of the slurry at the time of coating the slurry for forming the porous coating layer was controlled to 25°C, and the temperature of the coagulation solution was controlled to 17°C when immersed in the coagulation solution.

Example 3

When applying the slurry for forming the porous coating layer, the temperature of the slurry is controlled to 25°C, the temperature of the coagulating solution is controlled to 17°C when the coagulant is immersed, and the temperature of the rinsing solutions 1 and 2 is controlled to 40°C, respectively. A lithium secondary battery was manufactured in the same manner as in Example 1, except that the temperature of 3 was controlled at 45°C and the residence time of the coagulation/rinse solution was controlled to 70 sec.

Example 4

When applying the slurry for forming the porous coating layer, the temperature of the slurry is controlled to 25°C, and when the coagulant is immersed, the temperature of the coagulation solution is controlled to 17°C, and the temperature of the rinse liquids 1 and 2 is respectively controlled to 25°C, and the rinse liquid is applied. A lithium secondary battery was prepared in the same manner as in Example 1, except that the temperature of 3 was controlled to 30° C., and the weight ratio of N-methyl-2-pyrrolidone and water in the coagulation solution was controlled to 2:8. .

Example 5

A lithium secondary battery was manufactured in the same manner as in Example 4, except that the weight ratio of N-methyl-2-pyrrolidone and water in the coagulation solution was controlled to 4:6.

Comparative Example 1

Lithium secondary charging in the same manner as in Example 1, except that the temperature of the slurry when applying the slurry for forming the porous coating layer, the temperature of the coagulating liquid when immersed in the coagulant, and the temperature of the rinsing solutions 1 to 3 were all controlled to 25°C. Paper was prepared.

Comparative Examples 2 to 3

Lithium secondary charging in the same manner as in Example 1, except that the temperature of the slurry when applying the slurry for forming the porous coating layer, the temperature of the coagulating liquid when immersed in the coagulant, and the temperature of the rinse solutions 1 to 3 were controlled as shown in Table 1. Paper was prepared.

Experimental Example

Performance was tested as follows using the lithium secondary batteries according to Examples 1 to 5 and Comparative Example 1. Table 1 shows the results.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Process conditions Slurry temperature (℃) 15 25 25 25 25 25 25 25 Coagulation liquid temperature (℃) 25 17 17 17 17 25 23 35 Rinse solution 1 (℃) 25 25 40 25 25 25 25 25 Rinse solution 2 (℃) 25 25 40 25 25 25 25 25 Rinse solution 3 (℃) 25 25 45 30 30 25 25 25 Coagulation/rinse solution retention time (sec) 105sec 105sec 70sec 105sec 105sec 105sec 105sec 105sec Solvent in coagulation solution: weight ratio of non-solvent 1: 9 1: 9 1: 9 2: 8 4: 6 1: 9 1: 9 1: 9 Properties Separator thickness (㎛) 12.9 12.8 12.9 12.7 12.6 14.5 14.9 14.9 Application amount (g/m ² ) 5.1 5.1 5.1 5.1 5.1 5.1 5.8 4.5 Fill density (g/cc) 1.31 1.34 1.31 1.38 1.42 0.93 0.98 0.76 Adhesion (gf/25mm) 45 50 63 55 66 26 33 25 Resistance (ohm) 0.55 0.53 0.52 0.51 0.69 0.60 0.61 0.57 Remark Lower slurry temperature Lowering the coagulating fluid temperature Lowering the coagulation liquid temperature and increasing the rinse liquid temperature Lowering the coagulation temperature,
Coagulant concentration control Lowering the coagulation temperature,
Coagulant concentration control Room temperature (25℃) Little difference in temperature between slurry/coagulant and rinse liquid The temperature of the coagulating liquid is above room temperature

Comparative Example 1 is a case where the temperature of the slurry, the coagulating liquid, and the rinsing liquid is maintained at room temperature (25°C).

As can be seen from Table 1, in the case of Examples 1 to 5, the adhesive strength was improved by about 2 times or more compared to the case where the temperature of the coagulating and rinsing liquid was maintained at room temperature. In addition, Examples 1 to 5 in terms of resistance exhibited a value equal to or less than or equal to Comparative Example 1.

On the other hand, it can be estimated whether the porous coating layer has uniform pores from the filling density. Specifically, the filling density indicates the application amount of the coating layer applied to a certain thickness, and when the filling density is high, it has uniform pores, and when the filling density is low, it is highly likely to have uneven pores.

From this, it was confirmed that Examples 1 to 5 have a higher filling density than Comparative Example 1, from which the porous coating layers of Examples 1 to 5 form uniform pores.

In Comparative Example 2, the temperature of the slurry and the temperature of the coagulating liquid were 20°C or higher, and the difference between the temperature of the slurry and the temperature of the coagulating liquid and the rinse liquid was less than 5°C. In this case, it was confirmed that due to excessive phase separation, the adhesive strength with the electrode (Lami Strength) was lowered, and the filling density was also lower than in the example, and thus had uneven pores.

Comparative Example 3 is a case where the temperature of the slurry and the temperature of the coagulating solution are 20°C or higher. In this case, it was confirmed that both the temperature of the slurry and the temperature of the coagulating liquid were higher than or equal to the temperature of the rinse liquid, and the adhesive strength with the electrode was remarkably lower, and the filling density was also lower than that of the example, and had uneven pores.

(1) Adhesion measuring method

In the same manner as in Example 1-1), a negative electrode was prepared, cut to a size of 15 mm X 100 mm, and prepared. The separators prepared in Examples and Comparative Examples were prepared by cutting to a size of 15 mm X 100 mm. After the prepared separator and the cathode overlapped each other, they were sandwiched between 100 µm PET films, and then bonded using a flat plate press. At this time, the conditions of the flat plate press were heated for 1 second at a pressure of 8.5 MPa at 90°C. The outermost surface of the separator (adhesive layer or porous coating layer) is peeled off by attaching the ends of the bonded separator and the cathode to the UTM equipment (LLOYD Instrument LF Plus) and applying a force of 180° at a measurement speed of 300 mm/min. The force required to be measured was measured.

(2) Battery resistance evaluation method

AC resistance of the lithium secondary battery prepared in Examples and Comparative Examples was measured, and the results are shown in Table 1. At this time, the AC resistance is a value measured at 1KHz with Hioki.

(3) Measuring method of filling density

The filling density can be calculated by dividing the coating amount (g/m ² ) of the slurry for forming a coated porous coating layer per unit area by dividing the total thickness of the membrane by the thickness (µm) of the pure porous coating layer excluding the thickness of the porous polymer substrate, and as a result Table 1 shows.

Claims (19)

(S1) applying a slurry for forming a porous coating layer comprising inorganic particles, a binder polymer, and a solvent for the binder polymer on at least one surface of the porous polymer substrate;
(S2) immersing the result of the step (S1) in a coagulating solution containing a non-solvent for the binder polymer; And
(S3) and the step of introducing and drying the result of the step (S2) in the rinse solution,
At least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulating solution is immersed in the step (S2) is controlled to be less than 20°C,
At least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulant is immersed in the step (S2) is 5 than the temperature of the rinse solution when the rinse solution is added in the step (S3). A method of manufacturing a separation membrane for an electrochemical device, which is controlled to be low to 25°C.
According to claim 1,
It is to control at least any one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulating solution is immersed in the step (S2) to 5°C or more and less than 20°C. Manufacturing method.
According to claim 1,
The temperature difference between at least one of the temperature of the slurry when the slurry is applied in the step (S1) and the temperature of the coagulating solution when the coagulant is immersed in the step (S2), and the temperature difference between the rinse solution when the rinse solution is added in the step (S3). The method of manufacturing a separation membrane for an electrochemical device, which is controlled at 15°C to 25°C.
According to claim 1,
The solvent is capable of dissolving 10 wt% or more of the binder polymer at 25° C., and includes at least one selected from N-methyl-2-pyrrolidone, dimethylacetamide, and dimethylformamide. Manufacturing method of the separation membrane.
According to claim 1,
The non-solvent is capable of dissolving less than 5 wt% of the binder polymer at 25°C, and includes one or more selected from water, methanol, ethanol, propyl alcohol, butyl alcohol, butanediol, ethylene glycol, propylene glycol, and tripropylene glycol. That is, a method of manufacturing a separation membrane for an electrochemical device.
According to claim 1,
The coagulation solution is a method of manufacturing a separator for an electrochemical device, wherein the content of the non-solvent is 100 wt% or more in 100 wt% of the coagulation solution.
According to claim 1,
The rinse liquid contains a non-solvent, the content of the non-solvent in 100 wt% of the rinse liquid is 90 wt% or more, the method of manufacturing a separator for an electrochemical device.
According to claim 1,
The step (S3) is a method of preparing a separator for an electrochemical device, in which a plurality of rinsing liquids are prepared, and the result of the step (S2) is sequentially immersed in each rinsing liquid for a predetermined time. .
The method of claim 8,
The temperature of the first rinse liquid among the plurality of rinse liquids is controlled to a temperature higher than the temperature of the coagulating liquid when the coagulant is immersed, and the temperature of the last rinse liquid is controlled to a temperature lower than the drying temperature. Method of manufacturing a separator.
The method of claim 8,
The plurality of rinsing liquid is a method of manufacturing a separator for an electrochemical device, in which the temperature of the rinsing liquid is sequentially increased from the first rinsing liquid to the last rinsing liquid.
According to claim 1,
After the step (S3), further comprising the step (S4) of annealing the result of the step (S3) in an annealing tank, the method of manufacturing a separation membrane for an electrochemical device.
According to claim 1,
The porous polymer substrate includes a thermoplastic resin having a melting temperature of less than 200°C, a thickness of 4 µm to 15 µm, and a porosity of 30% to 70%, which is a method for manufacturing a separator for an electrochemical device.
According to claim 1,
The thickness of the porous coating layer is 1.5㎛ to 4.0㎛, the filling density of the porous coating layer is 1 g / cc to 1.5 g / cc, the manufacturing method of the separator for an electrochemical device.
According to claim 1,
The inorganic particles do not undergo oxidation and/or reduction reactions in the operating voltage range of the electrochemical device (0 to 5 V based on Li/Li+), and the average particle diameter (D50) of the particles is 0.1 μm to 2.5 μm, Method of manufacturing a separator for an electrochemical device.
According to claim 1,
The binder polymer is polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polyvinylidene fluoride-trifluoro Propylene (polyvinylidene fluoride-co-trifluoropropylene), polyvinylidene fluoride-co-tetrafluoropropylene, polymethylmethacrylate, polyethylhexyl acrylate, polybutyl Copolymer of acrylate (polybutylacrylate), polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, ethylhexyl acrylate and methyl methacrylate , Ethylene vinyl acetate copolymer, poly(ethylene oxide), polyarylate, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate Cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, cyluanoethylsucrose, flululan, carboxyl Methyl cellulose thyl cellulose) or a mixture of two or more of them, a method of manufacturing a separator for an electrochemical device.
According to claim 1,
The weight ratio of the inorganic particles and the binder polymer is 20:80 to 95:5, the method of manufacturing a separator for an electrochemical device.
Obtained according to the method of any one of claims 1 to 16,
A separator comprising a porous polymer substrate and a porous coating layer formed on at least one surface of the porous polymer substrate,
Here, the porous coating layer includes inorganic particles and a binder polymer,
The porous coating layer includes at least one node including a binder polymer covering at least a portion of the inorganic particles and the surface of the inorganic particle and at least one filament formed in a thread shape from the binder polymer of the node, , One or more filaments extending from one node are formed, and the filaments are arranged in a way that connects one node to another node. The method of claim 17,
The thickness of the porous coating layer is 2㎛ to 4㎛, the filling density of the porous coating layer is 1 g / cc to 1.5 g / cc, separation membrane for electrochemical devices.
In the electrochemical device comprising an anode, a cathode, and a separator interposed between the anode and the cathode,
The separator is an electrochemical device for the electrochemical device according to claim 17.

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