WO2016175605A1 - Separator for electrochemical element having improved electrolyte wettability and electrochemical element comprising same separator - Google Patents

Separator for electrochemical element having improved electrolyte wettability and electrochemical element comprising same separator Download PDF

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Publication number
WO2016175605A1
WO2016175605A1 PCT/KR2016/004522 KR2016004522W WO2016175605A1 WO 2016175605 A1 WO2016175605 A1 WO 2016175605A1 KR 2016004522 W KR2016004522 W KR 2016004522W WO 2016175605 A1 WO2016175605 A1 WO 2016175605A1
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Prior art keywords
binder polymer
separator
solvent
lithium
inorganic particles
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PCT/KR2016/004522
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French (fr)
Korean (ko)
Inventor
이주성
진선미
Original Assignee
주식회사 엘지화학
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Priority claimed from KR1020160052382A external-priority patent/KR102028113B1/en
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to US15/548,185 priority Critical patent/US10581045B2/en
Publication of WO2016175605A1 publication Critical patent/WO2016175605A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a separator for an electrochemical device with improved electrolyte impregnation and an electrochemical device including the separator.
  • Electrochemical devices are the most attention in this respect, and among them, the development of a secondary battery capable of charging and discharging has become a focus of attention.
  • the electrochemical device has been developed by the continuous research, the electrode active material has improved a lot of performance, especially the output.
  • the secondary batteries currently applied lithium secondary batteries developed in the early 1990s have been in the spotlight for their advantages of higher operating voltage and higher energy density than conventional batteries such as Ni-MH.
  • electrochemical devices are produced by many companies, but their safety characteristics show different aspects. It is very important to evaluate the safety and secure the safety of these electrochemical devices. The most important consideration is that an electrochemical device should not injure the user in the event of a malfunction. For this purpose, safety standards strictly regulate the ignition and smoke in the electrochemical device.
  • the separator of the electrochemical device plays an important role of passing the electrolyte or the ions while isolating the cathode and the anode to prevent short circuit between the two electrodes.
  • the separator is required for various characteristics from an electrical, chemical and mechanical point of view.
  • the separator is firmly adhered to the electrode, and at the same time, it is required to have a sufficient mechanical strength even though it is thin for light weight and compactness of the electrochemical device.
  • Such a separator may be made of a polyolefin-based porous polymer substrate, but the porous polymer substrate has a problem in that electrolyte solution wettability is insufficient in comparison with an electrode. This problem also applies to the case where a porous coating layer including a mixture of inorganic particles and a binder polymer is formed on at least one surface of the porous polymer substrate, even if the electrolyte solution impregnation of the porous coating layer is improved. Because it does not.
  • the problem to be solved by the present invention is to provide a separator excellent in electrolyte solution impregnation of the porous polymer substrate while showing a strong adhesive force with the electrode.
  • Another problem to be solved by the present invention is to provide an electrochemical device that is improved by the battery life characteristics while the activation process time is shortened by including the separator.
  • a porous polymer substrate having a plurality of pores; And a layer formed from at least one surface of the porous polymer substrate formed from a binder polymer solution including a first binder polymer and a second binder polymer, wherein the horizontal axis is a frequency (rad / s) converted to a log scale.
  • the first binder polymer includes 30% by weight of methanol in a range of 0.01 to 10 rad / s.
  • the slope of the frequency-storage modulus curve is greater than 0 and less than or equal to 1.0 when added to the solvent at a concentration of 3% by weight, and the second binder polymer is added at a concentration of 3% by weight in a solvent containing 30% by weight of methanol.
  • a separator for an electrochemical device characterized in that the slope of the storage modulus curve is greater than 1.0 and less than 2.0.
  • the first binder polymer and the second binder polymer may be used in a weight ratio composition of 20: 1 to 2: 1.
  • Inorganic particles may be further included in the layer including the first binder polymer and the second binder polymer.
  • the inorganic particles may be inorganic particles having a dielectric constant of about 5 or more, inorganic particles having lithium ion transfer ability, or mixtures thereof.
  • the dielectric constant of about 5 or more inorganic particles are boehmite, BaTiO 3, Pb (Zr x Ti 1-x) O 3 (PZT, where, 0 ⁇ x ⁇ 1 Im), Pb 1 - x La x Zr 1 - y Ti y O 3 (PLZT, where 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1), (1-x) PB (Mg 1/3 Nb 2/3 ) O 3 -xPbTiO 3 (PMN-PT, where 0 ⁇ x ⁇ 1), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 and SiC It may be any one or a mixture of two or more thereof.
  • the inorganic particles having a lithium ion transfer ability include lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li x Ti y (PO 4 ) 3 , 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 3), and lithium aluminum titanium phosphate (Li x Al y Ti z (PO 4 ) 3 , 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 3), (LiAlTiP) x O y series glass (0 ⁇ x ⁇ 4, 0 ⁇ y ⁇ 13), lithium lanthanum titanate (Li x La y TiO 3 , 0 ⁇ x ⁇ 2, 0 ⁇ y ⁇ 3), lithium germanium thiophosphate (Li x Ge y P z S w , 0 ⁇ x ⁇ 4 , 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ w ⁇ 5), lithium nitride (Li
  • (S1) preparing a porous polymer substrate having a plurality of pores; (S2) preparing a binder polymer solution including a first binder polymer and a second binder polymer, a solvent for dissolving both of the binder polymers, and a non-solvent not dissolving both of the binder polymers; And (S3) coating the binder polymer solution on at least one surface of the porous polymer substrate, and separating the phases under humidified conditions.
  • a method of manufacturing a separator for an electrochemical device is provided.
  • the solvent is acetone, dimethyl acetamide (DMAc), dimethyl formamide (DMF), tetrahydrofuran, tetrahydrofurane, methylene chloride (MC), chloroform, N It may be any one selected from the group consisting of -methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP) and cyclohexane (cyclohexane) or a mixture of two or more thereof.
  • the non-solvent may be any one selected from the group consisting of methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate and water, or a mixture of two or more thereof. have.
  • the weight ratio of the solvent and the non-solvent may be 98: 2 to 50:50.
  • the humidification condition may be a relative humidity of 40 to 80% at a temperature of 25 to 80 °C.
  • the separator prepared according to one aspect of the present invention can not only be firmly adhered to the electrode by the binder polymer distributed on the surface, but also the electrolyte impregnating property of the porous polymer substrate due to the binder polymer penetrated and coated on the porous polymer substrate. Has the effect of improving.
  • a separator includes a porous polymer substrate having a plurality of pores; And a layer formed from at least one surface of the porous polymer substrate formed from a binder polymer solution including a first binder polymer and a second binder polymer, wherein the horizontal axis is a frequency (rad / s) converted to a log scale.
  • the first binder polymer includes 30% by weight of methanol in a range of 0.01 to 10 rad / s.
  • the slope of the frequency-storage modulus curve is greater than 0 and less than or equal to 1.0 when added to the solvent at a concentration of 3% by weight, and the second binder polymer is added at a concentration of 3% by weight in a solvent containing 30% by weight of methanol.
  • the slope of the storage modulus curve is greater than 1.0 and less than 2.0.
  • the 'methanol' is used as a non-solvent for the binder polymer, the storage modulus of the binder polymer is greatly different depending on the type and content of the non-solvent.
  • solvent is a solvent for the binder polymer.
  • 'Storage modulus' refers to the amount of elastic energy accumulated in a vibrating sample, the slope of the storage modulus of the ideal binder polymer solution is 2, but the slope of the storage modulus when the phase separation occurs with respect to the non-solvent Tends to be lower.
  • the slope of storage modulus when 30% by weight of methanol is added to the solvent, when the slope of storage modulus is 1 or less, it is sensitive to humidifying phase separation, which is advantageous for forming an electrode adhesive layer, and when the slope of storage modulus is greater than 1, it is not sensitive to humidification phase separation.
  • the drying process it is possible to continuously move into the pores of the porous coating or the porous polymer substrate to improve the electrolyte impregnation characteristics.
  • the horizontal axis is the frequency (rad / s) of the binder polymer solution converted to log scale, and the vertical axis is the logarithmic binder polymer.
  • the frequency-storage modulus curve which is the storage modulus of solution (Pa)
  • the slope of the frequency-storage modulus curve of the ideal binder polymer solution is that the first binder polymer should exhibit fast phase separation behavior under humidified phase separation conditions. Theoretically, it is required to be greater than 0 and less than or equal to 1.0.
  • Non-limiting examples of such a first binder polymer include polyvinylidene fluoride (PVDF), PVdF-HFP, PVdF-HFP having a HFP substitution rate of 9% or less, a PVDF copolymer having a low degree of copolymer substitution, or a mixture thereof. Etc., but is not limited thereto.
  • the horizontal axis is the frequency (rad / s) of the binder polymer solution converted to the log scale
  • the vertical axis is the logarithmic binder polymer.
  • the slope of the frequency-storage modulus curve of the ideal binder polymer solution is that the second binder polymer should exhibit slow phase separation behavior under humidified phase separation conditions. In theory it is required to be greater than 1.0 and less than or equal to 2.0.
  • Non-limiting examples of such a second binder polymer is PVdF-HFP, PVdF-HFP, PVdF-CTFE, polyvinylacetate, cyanoethyl pullulan, cyanoethylpolypoly with 12% or more HFP substitution rate Vinyl alcohol (cyanoethyl polyvinylalcohol), PVDF having a high degree of copolymer substitution, or a mixture thereof, but is not limited thereto.
  • One of the ways to enhance the storage modulus is to enhance the storage modulus by adding a non-solvent.
  • the first binder polymer and the second binder polymer may be used in a weight ratio composition of 20: 1 to 2: 1.
  • the improvement of the electrolyte impregnation characteristics is insignificant, and when the first binder polymer is used less than the lower limit, phase separation may occur slowly, resulting in poor coating productivity and insufficient electrode adhesion of the separator.
  • the solvent that can be used in the present invention acetone (acetone), dimethyl acetamide (DMAc), dimethylformamide (dimethylformamide, DMF), tetrahydro furan (tetrahydro furan), methylene chloride (MC), It may be any one selected from the group consisting of chloroform, N-methyl-2-pyrrolidone (NMP) and cyclohexane, or a mixture of two or more thereof. It is not limited only to this.
  • the solvent may be removed in the manufacturing process of the electrochemical device, since the solvent may cause various side reactions when remaining in the finally manufactured electrochemical device.
  • the non-solvent may be any one selected from the group consisting of methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate and water, or a mixture of two or more thereof. It is possible, but not limited to.
  • the mixing weight ratio may be 99: 1 to 40:60, or 98: 2 to 50:50, and when the mixing weight ratio range is satisfied, the binder polymer may be used in the porous polymer substrate. It can be permeated to form a coating.
  • the binder polymer solution according to the present invention may further include inorganic particles.
  • a porous coating layer in which the binder polymer and the inorganic particles are mixed may be formed on one or both surfaces of the porous polymer substrate.
  • the inorganic particles serve as a kind of spacer that can maintain the physical form of the porous coating layer, thereby suppressing thermal shrinkage of the porous polymer substrate when the electrochemical device is overheated, and the cathode and the anode even when the porous polymer substrate is damaged. To prevent direct contact.
  • such a porous coating layer may be prepared by coating a slurry including a solvent, a non-solvent, a binder polymer and inorganic particles by dip coating on a porous polymer substrate, and then drying.
  • the inorganic particles that can be used in the present invention is not particularly limited as long as it is electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as the oxidation and / or reduction reactions do not occur in the operating voltage range (for example, 0 to 5 V on the basis of Li / Li + ) of the applied electrochemical device.
  • the ionic conductivity of the electrolyte may be improved by contributing to an increase in the dissociation degree of the electrolyte salt such as lithium salt in the liquid electrolyte.
  • the inorganic particles may include high dielectric constant inorganic particles having a dielectric constant of 5 or more, or 10 or more.
  • inorganic particles having a dielectric constant of 5 or more include boehmite, BaTiO 3 , Pb (Zr x Ti 1-x ) O 3 (PZT, where 0 ⁇ x ⁇ 1), Pb 1 - x La x Zr 1 - y Ti y O 3 (PLZT, where 0 ⁇ x ⁇ 1, 0 ⁇ y ⁇ 1), (1-x) Pb (Mg 1/3 Nb 2/3 ) O 3 -xPbTiO 3 (PMN-PT, where 0 ⁇ x ⁇ 1), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , SiC and
  • an inorganic particle having lithium ion transfer ability that is, an inorganic particle containing lithium element but having a function of transferring lithium ions without storing lithium
  • inorganic particles having a lithium ion transfer capacity include 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) x O y series glasses such as O 5 (0 ⁇ x ⁇ 4, 0 ⁇ y ⁇ 13), lithium lanthanum titanate (Li x La y TiO 3 , 0 ⁇ x ⁇ 2,
  • Lithium germanium thiophosphate such as Li x Ge y P z S w , 0 ⁇ x ⁇ 4, 0 ⁇ y ⁇ 1, 0 ⁇ z ⁇ 1, 0 ⁇ w ⁇ 5), Li 3 N, etc.
  • SiS 2 series glasses Li x Si y S z , 0 ⁇ x ⁇ 3) such as Ride (Li x N y , 0 ⁇ x ⁇ 4, 0 ⁇ y ⁇ 2), Li 3 PO 4 -Li 2 S-SiS 2, etc.
  • LiI-Li 2 SP 2 S 5 P 2 S 5 series glass LiI-Li 2 SP 2 S 5 P 2 S 5 series glass (Li x P y S z , 0 ⁇ x ⁇ 3, 0 ⁇ y ⁇ 3, 0 ⁇ z ⁇ 7), or a mixture thereof.
  • the size of the inorganic particles is not limited, but for proper porosity of the separator, the average particle size may be in the range of 0.001 ⁇ m to 10 ⁇ m.
  • the composition ratio of the inorganic particles and the binder polymer in the porous coating layer may be, for example, about 50:50 to about 99: 1, or about 60:40 to about 95: 5.
  • the thickness of the porous coating layer composed of the inorganic particles and the binder polymer is not particularly limited, but may range from about 0.01 to about 20 ⁇ m.
  • the pore size and porosity are also not particularly limited, but the pore size may range from about 0.01 to about 5 ⁇ m, and the porosity may range from about 5 to about 75%.
  • the component of the porous coating layer in addition to the inorganic particles and the binder polymer described above, other additives commonly used in the art may be further included.
  • the binder polymer is attached to each other (that is, the binder polymer is connected and fixed between the inorganic particles) so that the inorganic particles are bound to each other, and the porous coating layer is formed of the porous polymer substrate by the binder polymer. It remains bound with.
  • the interstitial volume between the inorganic particles which is a space defined by the inorganic particles that are substantially interviewed, becomes the pores of the porous coating layer. .
  • the porous polymer substrate may be used as long as it is a porous polymer substrate commonly used in an electrochemical device.
  • a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not particularly limited thereto.
  • Non-limiting examples of the polyolefin-based porous membrane polyolefin-based porous membrane, polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof And a membrane formed of a polymer.
  • the nonwoven fabric may be, for example, polyethylene terephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, or polycarbonate. ), Polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, polyethylenenaphthalene, etc. Or the nonwoven fabric formed from the polymer which mixed these is mentioned.
  • the structure of the nonwoven can be a spunbond nonwoven or melt blown nonwoven composed of long fibers.
  • the thickness of the porous polymer substrate is not particularly limited, but may be 5 to 50 ⁇ m, and the pore size and pore present in the porous polymer substrate are also not particularly limited, but may be 0.01 to 50 ⁇ m and 10 to 95%, respectively.
  • the method of coating the solution containing the binder polymer or the slurry containing the binder polymer and the inorganic particles on the porous polymer substrate may use a conventional coating method known in the art, for example, dip coating, Various methods may be used, such as die coating, roll coating, comma coating, or a mixture thereof.
  • the slurry may be selectively coated on both surfaces or only one surface of the porous polymer substrate.
  • the coating process can be carried out in a range of relative humidity, preferably at a temperature of 25 to 80 °C under a relative humidity of 40 to 80%.
  • a temperature during the coating process is lower than the lower limit, drying of the porous coating layer is slow, and when the temperature is higher than the upper limit, the time required for phase separation of the binder polymer may be insufficient.
  • the relative humidity in the coating process is lower than the lower limit, the amount of moisture, which is a non-solvent introduced during the vapor-induced phase separation, is difficult to separate the phase, and when the relative humidity is higher than the upper limit, moisture is condensed in the drying furnace. Problems will arise.
  • the first binder polymer and the second binder polymer dissolved in the solution / slurry during the drying process have different phase transition characteristics by humidifying phase separation phenomenon known in the art.
  • Binder polymers having a slope of the frequency-storage modulus curve greater than 1.0 and less than or equal to 2.0 have a slow phase separation rate under the same nonsolvent, and require a relatively large amount of nonsolvent required for phase separation.
  • it may exist in the first half of the thickness direction of the porous coating layer after coating or penetrate into the porous polymer substrate.
  • the binder polymer which makes the slope of the frequency-storage modulus curve greater than 0 and equal to or less than 1.0 has a high phase separation speed, requires a small amount of nonsolvent required for phase separation, and concentrates on the separator surface. Therefore, according to one embodiment of the present invention, some of the binder polymers are intensively distributed on the surface of the separator and exhibit excellent adhesion with the electrode, while the other binder polymer penetrates into the porous polymer substrate to form a coating and has an excellent electrolyte solution of the porous polymer substrate. Show impregnation.
  • the drying process carried out subsequently may be carried out by methods known in the art and may be batchwise or continuously using an oven or heated chamber in a temperature range that takes into account the vapor pressure of the solvent used.
  • the drying is to almost eliminate the solvent present in the slurry, which is preferably as fast as possible in view of productivity and the like, for example, may be carried out for a time of 1 minute or less, preferably 30 seconds or less.
  • an electrochemical device includes a cathode, an anode, and a separator interposed between the cathode and the anode, wherein the separator is the separator of the present invention described above.
  • the electrochemical device includes all devices that undergo an electrochemical reaction, and specific examples include capacitors such as all kinds of primary, secondary, fuel cell, solar cell, or super capacitor devices. capacitor).
  • capacitors such as all kinds of primary, secondary, fuel cell, solar cell, or super capacitor devices. capacitor).
  • 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 among the secondary batteries is preferable.
  • the electrode to be applied to the electrochemical device according to an embodiment of the present invention is not particularly limited, and according to a conventional method known in the art, the electrode active material may be manufactured in a form bound to the electrode current collector.
  • Non-limiting examples of the cathode active material of the electrode active material may be a conventional cathode active material that can be used for the cathode of the conventional electrochemical device, in particular lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide or a combination thereof One lithium composite oxide can be used.
  • Non-limiting examples of the anode active material may be a conventional anode active material that can be used in the anode of the conventional electrochemical device, in particular lithium metal or lithium alloys, carbon, petroleum coke, activated carbon, Lithium adsorption materials such as graphite or other carbons are preferable.
  • Non-limiting examples of the cathode current collector is a foil made by aluminum, nickel or a combination thereof, and non-limiting examples of the anode current collector by copper, gold, nickel or a copper alloy or a combination thereof. Foils produced.
  • the electrolyte salt included in the nonaqueous electrolyte solution which can be used in one embodiment of the present invention is a lithium salt.
  • the lithium salt may be used without limitation those conventionally used in the lithium secondary battery electrolyte.
  • For example is the above lithium salt anion F -, Cl -, Br - , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 - , (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, ( CF 3 SO 2) 3 C -
  • organic solvent included in the non-aqueous electrolyte solution those conventionally used in the lithium secondary battery electrolyte solution can be used without limitation.
  • ethers, esters, amides, linear carbonates, cyclic carbonates, and the like can be used alone or in combination of two or more. It can be mixed and used.
  • carbonate compounds which are typically cyclic carbonates, linear carbonates, or mixtures thereof may be included.
  • cyclic carbonate compound examples include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate and any one selected from the group consisting of halides thereof or mixtures of two or more thereof.
  • halides include, for example, fluoroethylene carbonate (FEC), but are not limited thereto.
  • linear carbonate compounds include any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate.
  • DMC dimethyl carbonate
  • DEC diethyl carbonate
  • DPC dipropyl carbonate
  • EMC ethylmethyl carbonate
  • methylpropyl carbonate and ethylpropyl carbonate methylpropyl carbonate and ethylpropyl carbonate.
  • ethylene carbonate and propylene carbonate which are cyclic carbonates among the carbonate-based organic solvents, are high viscosity organic solvents and have a high dielectric constant, which may dissociate lithium salts in the electrolyte more effectively.
  • ethylene carbonate and propylene carbonate which are cyclic carbonates among the carbonate-based organic solvents, are high viscosity organic solvents and have a high dielectric constant, which may dissociate lithium salts in the electrolyte more effectively.
  • any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, and ethylpropyl ether, or a mixture of two or more thereof may be used. It is not limited.
  • Ester in the organic solvent is methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -caprolactone, ⁇ -valerolactone and ⁇ Any one or a mixture of two or more selected from the group consisting of caprolactone may be used, but is not limited thereto.
  • the injection of the nonaqueous electrolyte may be performed at an appropriate step in the manufacturing process of the electrochemical device, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before the electrochemical device assembly or the final step of the electrochemical device assembly.
  • the electrochemical device according to the present invention in addition to the winding (winding) which is a general process, the lamination (stacking) and folding (folding) process of the separator and the electrode is possible.
  • the external shape of the electrochemical device is not particularly limited, but may be cylindrical, square, pouch or coin type using a can.
  • the slurry was coated on both sides of a polyethylene porous membrane (ND307B, Asahi Co., Ltd.) having a thickness of 7 ⁇ m by dip coating to form a porous coating layer.
  • the thickness of the porous coating layer was adjusted to about 4 ⁇ m.
  • a separator was prepared in the same manner as in Example 1, except that 3.3 parts by weight of polyvinylidene fluoride (LBG, Arkema, HFP content 5%) was used alone.
  • a separator was prepared in the same manner as in Example 1, except that 1.0 parts by weight of an acrylic copolymer (CSB130, Toyo ink Co., Ltd.), a particulate water-dispersible emulsion binder polymer, was used as the binder polymer and water was used as the solvent.
  • CSB130 acrylic copolymer
  • Toyo ink Co., Ltd. a particulate water-dispersible emulsion binder polymer

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Abstract

The present invention relates to a separator for an electrochemical element having improved electrolyte wettability and an electrochemical element comprising the separator. A layer containing at least two binder polymers having different slopes on the frequency-storage elastic modulus curve is formed on a surface of the separator, and here, one of the binder polymers is concentratedly distributed on the surface of the separator, thereby enabling a strong adhesion between the separator and the electrode, and the other binder polymer permeates into and is coated on a porous polymer substrate, thereby improving electrolyte wettability.

Description

전해액 함침성이 향상된 전기화학소자용 세퍼레이터 및 상기 세퍼레이터를 포함하는 전기화학소자A separator for an electrochemical device with improved electrolyte impregnation and an electrochemical device including the separator
본 출원은 2015년 4월 30일에 출원된 한국특허출원 제10-2015-0061979호 및 2016년 4월 28일에 출원된 한국특허출원 제10-2016-0052382호에 기초한 우선권을 주장하며, 해당 출원의 명세서에 개시된 모든 내용은 본 출원에 원용된다.This application claims the priority based on Korean Patent Application No. 10-2015-0061979 filed April 30, 2015 and Korean Patent Application No. 10-2016-0052382 filed April 28, 2016, All contents disclosed in the specification of the application are incorporated in this application.
본 발명은 전해액 함침성이 향상된 전기화학소자용 세퍼레이터 및 상기 세퍼레이터를 포함하는 전기화학소자에 관한 것이다.The present invention relates to a separator for an electrochemical device with improved electrolyte impregnation and an electrochemical device including the separator.
최근, 에너지 저장 기술에 대한 관심이 갈수록 높아지고 있다. 휴대폰, 캠코더 및 노트북, 나아가 전기 자동차의 에너지까지 적용 분야가 확대되면서 전기화학소자의 연구 및 개발에 대한 노력이 점점 구체화되고 있다. 전기화학소자는 이러한 측면에서 가장 주목받고 있는 분야이며, 그 중에서도 충방전이 가능한 이차전지의 개발은 관심의 초점이 되고 있다.Recently, interest in energy storage technology is increasing. As the application fields of mobile phones, camcorders and laptops, and even electric vehicles have been expanded, efforts for research and development of electrochemical devices are becoming more concrete. Electrochemical devices are the most attention in this respect, and among them, the development of a secondary battery capable of charging and discharging has become a focus of attention.
전기화학소자는 지속적인 연구에 의해 전극활물질로서 그의 여러 성능, 특히 출력이 크게 개선된 것들이 개발되어 왔다. 현재 적용되고 있는 이차전지 중에서 1990년대 초에 개발된 리튬 이차전지는 Ni-MH 등의 재래식 전지에 비해서 작동 전압이 높고 에너지 밀도가 크다는 장점으로 각광을 받고 있다.The electrochemical device has been developed by the continuous research, the electrode active material has improved a lot of performance, especially the output. Among the secondary batteries currently applied, lithium secondary batteries developed in the early 1990s have been in the spotlight for their advantages of higher operating voltage and higher energy density than conventional batteries such as Ni-MH.
상기와 같은 전기화학소자는 많은 회사에서 생산되고 있으나 그들의 안전성 특성은 각각 다른 양상을 보인다. 이러한 전기화학소자의 안전성 평가 및 안전성 확보는 매우 중요하다. 가장 중요한 고려사항은 전기화학소자가 오작동시 사용자에게 상해를 입혀서는 아니된다는 것이며, 이러한 목적으로 안전규격은 전기화학소자 내의 발화 및 발연 등을 엄격히 규제하고 있다.Such electrochemical devices are produced by many companies, but their safety characteristics show different aspects. It is very important to evaluate the safety and secure the safety of these electrochemical devices. The most important consideration is that an electrochemical device should not injure the user in the event of a malfunction. For this purpose, safety standards strictly regulate the ignition and smoke in the electrochemical device.
전기화학소자의 세퍼레이터는, 캐소드와 애노드를 격리하여 양 전극의 단락을 방지하면서 전해질 또는 이온을 통과시키는 중요한 역할을 하는 것으로, 세퍼레이터에는 전기적, 화학적, 기계적인 관점에서 여러 가지 특성이 요구되고 있다.The separator of the electrochemical device plays an important role of passing the electrolyte or the ions while isolating the cathode and the anode to prevent short circuit between the two electrodes. The separator is required for various characteristics from an electrical, chemical and mechanical point of view.
예컨대, 세퍼레이터는 전극에 견고하게 접착되는 동시에, 전기화학소자의 경량화 및 컴팩트화를 위해 얇더라도 충분한 기계적 강도를 가질 것이 요구되고 있다.For example, the separator is firmly adhered to the electrode, and at the same time, it is required to have a sufficient mechanical strength even though it is thin for light weight and compactness of the electrochemical device.
이러한 세퍼레이터는 폴리올레핀계 다공성 고분자 기재를 포함하여 이루어지기도 하는데, 이러한 다공성 고분자 기재는 전극에 비해 전해액 함침성(wettability)이 부족한 문제점이 있다. 이러한 문제점은 상기 다공성 고분자 기재의 적어도 일면에, 무기물 입자와 바인더 고분자의 혼합물을 포함하여 이루어진 다공성 코팅층이 형성된 경우에도 해당되는데, 다공성 코팅층의 전해액 함침성이 향상되더라도 다공성 고분자 기재의 전해액 함침성은 향상되지 않기 때문이다.Such a separator may be made of a polyolefin-based porous polymer substrate, but the porous polymer substrate has a problem in that electrolyte solution wettability is insufficient in comparison with an electrode. This problem also applies to the case where a porous coating layer including a mixture of inorganic particles and a binder polymer is formed on at least one surface of the porous polymer substrate, even if the electrolyte solution impregnation of the porous coating layer is improved. Because it does not.
한편, 세퍼레이터의 두께 방향으로 바인더 고분자가 농도 구배를 이루면서 분포되도록 하되, 전극과의 접착이 이루어지는 세퍼레이터 표면에 바인더 고분자가 더 많이 분포되도록 바인더 고분자를 소정의 가습 조건에서 상분리시키는 방법이 제안되어 왔다. 그러나, 이러한 방법에 의해 세퍼레이터-전극 간의 접착력이 향상되더라도 다공성 고분자 기재의 전해액 함침성 증가는 기대하기 곤란하였다.Meanwhile, a method has been proposed in which the binder polymer is distributed in the thickness direction of the separator while having a concentration gradient, and the binder polymer is phase-separated under predetermined humidification conditions such that the binder polymer is more distributed on the surface of the separator where the adhesion with the electrode is performed. However, even if the adhesion between the separator and the electrode is improved by this method, it is difficult to expect an increase in the electrolyte solution impregnation of the porous polymer substrate.
따라서, 본 발명이 해결하고자 하는 과제는, 전극과 견고한 접착력을 나타내면서 다공성 고분자 기재의 전해액 함침성도 우수한 세퍼레이터를 제공하는데 있다.Accordingly, the problem to be solved by the present invention is to provide a separator excellent in electrolyte solution impregnation of the porous polymer substrate while showing a strong adhesive force with the electrode.
또한, 본 발명이 해결하고자 하는 다른 과제는, 상기 세퍼레이터를 포함하여 제조됨으로써 활성화 공정 시간이 단축되면서 전지 수명 특성이 개선된 전기화학소자를 제공하는데 있다.In addition, another problem to be solved by the present invention is to provide an electrochemical device that is improved by the battery life characteristics while the activation process time is shortened by including the separator.
상기 과제를 달성하기 위하여, 본 발명의 일 양태에 따르면, 다수의 기공을 갖는 다공성 고분자 기재; 및 제1 바인더 고분자와 제2 바인더 고분자를 포함하는 바인더 고분자 용액으로부터 형성되어 상기 다공성 고분자 기재의 적어도 일면에 형성된 층을 구비하며, 이 때, 횡축은 로그스케일로 변환된 진동수(rad/s)로 하고 종축은 로그스케일로 변환된 저장탄성률(MPa)로 하는 진동수-저장 탄성률 곡선에 있어서, 상기 진동수가 0.01 내지 10 rad/s를 나타내는 범위에서, 상기 제1 바인더 고분자는 메탄올 30중량%를 포함하는 용매 중에 3중량% 농도로 첨가되었을 때 진동수-저장 탄성률 곡선의 기울기가 0보다 크고 1.0 이하이고, 상기 제2 바인더 고분자는 메탄올 30중량%를 포함하는 용매 중에 3중량% 농도로 첨가되었을 때 진동수-저장 탄성률 곡선의 기울기가 1.0보다 크고 2.0 이하인 것을 특징으로 하는 전기화학소자용 세퍼레이터가 제공된다.In order to achieve the above object, according to an aspect of the present invention, a porous polymer substrate having a plurality of pores; And a layer formed from at least one surface of the porous polymer substrate formed from a binder polymer solution including a first binder polymer and a second binder polymer, wherein the horizontal axis is a frequency (rad / s) converted to a log scale. In the frequency-storage modulus curve, wherein the vertical axis is a storage modulus (MPa) converted into a log scale, the first binder polymer includes 30% by weight of methanol in a range of 0.01 to 10 rad / s. The slope of the frequency-storage modulus curve is greater than 0 and less than or equal to 1.0 when added to the solvent at a concentration of 3% by weight, and the second binder polymer is added at a concentration of 3% by weight in a solvent containing 30% by weight of methanol. A separator for an electrochemical device, characterized in that the slope of the storage modulus curve is greater than 1.0 and less than 2.0.
상기 제1 바인더 고분자와 제2 바인더 고분자는 20 : 1 내지 2 : 1의 중량비조성으로 사용될 수 있다.The first binder polymer and the second binder polymer may be used in a weight ratio composition of 20: 1 to 2: 1.
상기 제1 바인더 고분자와 제2 바인더 고분자를 포함하여 이루어진 층에 무기물 입자가 더 포함될 수 있다.Inorganic particles may be further included in the layer including the first binder polymer and the second binder polymer.
상기 무기물 입자는 유전율 상수가 약 5 이상인 무기물 입자, 리튬 이온 전달 능력을 갖는 무기물 입자, 또는 이들의 혼합물일 수 있다.The inorganic particles may be inorganic particles having a dielectric constant of about 5 or more, inorganic particles having lithium ion transfer ability, or mixtures thereof.
상기 유전율 상수가 약 5 이상인 무기물 입자는 보헤마이트, BaTiO3, Pb(ZrxTi1-x)O3(PZT, 여기서, 0<x<1임), Pb1 - xLaxZr1 - yTiyO3 (PLZT, 여기서, 0<x<1, 0<y<1임), (1-x)PB(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT, 여기서 0<x<1), 하프니아(HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2 및 SiC로 이루어진 군으로부터 선택되는 어느 하나 또는 이들중 2종 이상의 혼합물일 수 있다.The dielectric constant of about 5 or more inorganic particles are boehmite, BaTiO 3, Pb (Zr x Ti 1-x) O 3 (PZT, where, 0 <x <1 Im), Pb 1 - x La x Zr 1 - y Ti y O 3 (PLZT, where 0 <x <1, 0 <y <1), (1-x) PB (Mg 1/3 Nb 2/3 ) O 3 -xPbTiO 3 (PMN-PT, where 0 <x < 1), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 and SiC It may be any one or a mixture of two or more thereof.
상기 리튬 이온 전달 능력을 갖는 무기물 입자는 리튬포스페이트(Li3PO4), 리튬티타늄포스페이트(LixTiy(PO4)3, 0 < x < 2, 0 < y < 3), 리튬알루미늄티타늄포스페이트(LixAlyTiz(PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), (LiAlTiP)xOy 계열 glass (0 < x < 4, 0 < y < 13), 리튬란탄티타네이트(LixLayTiO3, 0 < x < 2, 0 <y < 3), 리튬게르마니움티오포스페이트(LixGeyPzSw, 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), 리튬나이트라이드(LixNy, 0 < x < 4, 0 < y < 2), SiS2 계열 glass(LixSiySz, 0 < x < 3, 0 < y < 2, 0 < z < 4) 및 P2S5 계열 glass(LixPySz, 0 < x < 3, 0 < y < 3, 0 < z < 7)로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The inorganic particles having a lithium ion transfer ability include lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li x Ti y (PO 4 ) 3 , 0 <x <2, 0 <y <3), and lithium aluminum titanium phosphate (Li x Al y Ti z (PO 4 ) 3 , 0 <x <2, 0 <y <1, 0 <z <3), (LiAlTiP) x O y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate (Li x La y TiO 3 , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (Li x Ge y P z S w , 0 <x <4 , 0 <y <1, 0 <z <1, 0 <w <5), lithium nitride (Li x N y , 0 <x <4, 0 <y <2), SiS 2 series glass (Li x Si y S z , 0 <x <3, 0 <y <2, 0 <z <4) and P 2 S 5 series glass (Li x P y S z , 0 <x <3, 0 <y <3, 0 <z <7) can be any one selected from the group consisting of or a mixture of two or more thereof.
본 발명의 다른 양태에 따르면, (S1) 다수의 기공을 갖는 다공성 고분자 기재를 준비하는 단계; (S2) 제1 바인더 고분자와 제2 바인더 고분자, 상기 바인더 고분자 둘다를 용해시키는 용매, 및 상기 바인더 고분자 둘다를 용해시키지 않는 비용매를 포함하는 바인더 고분자 용액을 준비하는 단계; 및 (S3) 상기 바인더 고분자 용액을 다공성 고분자 기재의 적어도 일면에 코팅하고, 가습 조건에서 상분리시키는 단계;를 포함하는 전기화학소자용 세퍼레이터의 제조방법이 제공된다.According to another aspect of the invention, (S1) preparing a porous polymer substrate having a plurality of pores; (S2) preparing a binder polymer solution including a first binder polymer and a second binder polymer, a solvent for dissolving both of the binder polymers, and a non-solvent not dissolving both of the binder polymers; And (S3) coating the binder polymer solution on at least one surface of the porous polymer substrate, and separating the phases under humidified conditions. A method of manufacturing a separator for an electrochemical device is provided.
상기 용매는 아세톤(acetone), 디메틸아세트아미드(dimethyl acetamide, DMAc), 디메틸포름아미드(dimethyl formamide, DMF), 테트라하이드로퓨란(tetrahydrofurane), 메틸렌 클로라이드(methylene chloride, MC), 클로로포름(chloroform), N-메틸-2-피롤리돈(N-methyl-2-pyrrolidone, NMP) 및 시클로헥산(cyclohexane)으로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The solvent is acetone, dimethyl acetamide (DMAc), dimethyl formamide (DMF), tetrahydrofuran, tetrahydrofurane, methylene chloride (MC), chloroform, N It may be any one selected from the group consisting of -methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP) and cyclohexane (cyclohexane) or a mixture of two or more thereof.
상기 비용매는 메탄올(methanol), 에탄올(ethanol), 이소프로필 알콜(isopropyl alcohol), 부탄올(butanol), 에틸아세테이트(ethyl acetate) 및 물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.The non-solvent may be any one selected from the group consisting of methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate and water, or a mixture of two or more thereof. have.
상기 용매와 비용매의 중량비는 98:2 내지 50:50일 수 있다.The weight ratio of the solvent and the non-solvent may be 98: 2 to 50:50.
상기 가습 조건은 25 내지 80℃의 온도에서 40 내지 80%의 상대 습도일 수 있다.The humidification condition may be a relative humidity of 40 to 80% at a temperature of 25 to 80 ℃.
본 발명의 일 측면에 따라 제조된 세퍼레이터는 표면에 분포된 바인더 고분자에 의해 전극에 견고하게 접착될 수 있을 뿐만 아니라, 다공성 고분자 기재에 스며들어 코팅되어 있는 바인더 고분자로 인해 다공성 고분자 기재의 전해액 함침성을 향상시키는 효과를 갖는다.The separator prepared according to one aspect of the present invention can not only be firmly adhered to the electrode by the binder polymer distributed on the surface, but also the electrolyte impregnating property of the porous polymer substrate due to the binder polymer penetrated and coated on the porous polymer substrate. Has the effect of improving.
이하, 본 발명에 대하여 상세히 설명하기로 한다. 이에 앞서, 본 명세서 및 특허청구범위에 사용된 용어 또는 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다. 따라서, 본 명세서에 기재된 실시예 구성은 본 발명의 가장 바람직한 일 실시예에 불과할 뿐이고 본 발명의 기술적 사상을 모두 대변하는 것은 아니므로, 본 출원시점에 있어서 이들을 대체할 수 있는 다양한 균등물과 변형예들이 있을 수 있음을 이해하여야 한다.Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in this specification and claims should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly introduce the concept of terms to explain their own invention in the best way. It should be interpreted as meanings and concepts in accordance with the technical spirit of the present invention based on the principle that it can be defined. Therefore, the exemplary embodiments described herein are only exemplary embodiments of the present invention and do not represent all of the technical ideas of the present invention, and therefore, various equivalents and modifications may be substituted for them at the time of the present application. It should be understood that there may be
본 발명의 일 측면에 따른 세퍼레이터는 다수의 기공을 갖는 다공성 고분자 기재; 및 제1 바인더 고분자와 제2 바인더 고분자를 포함하는 바인더 고분자 용액으로부터 형성되어 상기 다공성 고분자 기재의 적어도 일면에 형성된 층을 구비하며, 이 때, 횡축은 로그스케일로 변환된 진동수(rad/s)로 하고 종축은 로그스케일로 변환된 저장탄성률(MPa)로 하는 진동수-저장 탄성률 곡선에 있어서, 상기 진동수가 0.01 내지 10 rad/s를 나타내는 범위에서, 상기 제1 바인더 고분자는 메탄올 30중량%를 포함하는 용매 중에 3중량% 농도로 첨가되었을 때 진동수-저장 탄성률 곡선의 기울기가 0보다 크고 1.0 이하이고, 상기 제2 바인더 고분자는 메탄올 30중량%를 포함하는 용매 중에 3중량% 농도로 첨가되었을 때 진동수-저장 탄성률 곡선의 기울기가 1.0보다 크고 2.0 이하인 것을 특징으로 한다.A separator according to an aspect of the present invention includes a porous polymer substrate having a plurality of pores; And a layer formed from at least one surface of the porous polymer substrate formed from a binder polymer solution including a first binder polymer and a second binder polymer, wherein the horizontal axis is a frequency (rad / s) converted to a log scale. In the frequency-storage modulus curve, wherein the vertical axis is a storage modulus (MPa) converted into a log scale, the first binder polymer includes 30% by weight of methanol in a range of 0.01 to 10 rad / s. The slope of the frequency-storage modulus curve is greater than 0 and less than or equal to 1.0 when added to the solvent at a concentration of 3% by weight, and the second binder polymer is added at a concentration of 3% by weight in a solvent containing 30% by weight of methanol. The slope of the storage modulus curve is greater than 1.0 and less than 2.0.
상기에서 '메탄올'은 바인더 고분자에 대한 비용매로 사용된 것으로, 바인더 고분자의 저장탄성률(storage modulus)은 비용매의 종류 및 함량에 따라 크게 상이하게 된다.The 'methanol' is used as a non-solvent for the binder polymer, the storage modulus of the binder polymer is greatly different depending on the type and content of the non-solvent.
또한, 상기에서 '용매'라 함은 바인더 고분자에 대한 용매이다.In addition, the term "solvent" is a solvent for the binder polymer.
'저장 탄성률'은 진동하고 있는 시료 중에 축적되는 탄성 에너지의 크기를 나타내는 것으로, 이상적인(ideal) 바인더 고분자 용액의 저장탄성률의 기울기는 2이지만, 비용매에 대해서 상분리가 일어나는 경우에 상기 저장탄성률의 기울기는 낮아지는 경향을 보인다. 특히, 메탄올 30중량%를 용매에 첨가하는 경우, 저장탄성률의 기울기가 1 이하인 경우에는 가습 상분리에 민감하여 전극접착층 형성에 유리하며, 저장탄성률의 기울기가 1보다 큰 경우에는 가습 상분리에 민감하지 않아 건조 과정동안 다공성 코팅층 내부 혹은 다공성 고분자 기재의 기공내로 지속적으로 이동하여 전해액 함침 특성을 향상시킬 수 있다.'Storage modulus' refers to the amount of elastic energy accumulated in a vibrating sample, the slope of the storage modulus of the ideal binder polymer solution is 2, but the slope of the storage modulus when the phase separation occurs with respect to the non-solvent Tends to be lower. In particular, when 30% by weight of methanol is added to the solvent, when the slope of storage modulus is 1 or less, it is sensitive to humidifying phase separation, which is advantageous for forming an electrode adhesive layer, and when the slope of storage modulus is greater than 1, it is not sensitive to humidification phase separation. During the drying process, it is possible to continuously move into the pores of the porous coating or the porous polymer substrate to improve the electrolyte impregnation characteristics.
제1 바인더 고분자를 용매 및 비용매와 함께 포함하는 바인더 고분자 용액으로 제조할 경우, 횡축을 로그스케일로 변환된 바인더 고분자 용액의 진동수(rad/s)로 하고, 종축을 로그스케일로 변환된 바인더 고분자 용액의 저장탄성률(Pa)로 하는 진동수-저장탄성률 곡선에 있어서, 상기 제1 바인더 고분자는 가습 상분리 조건에서 빠른 상분리 거동을 나타내어야 한다는 점에서, 이상적인 바인더 고분자 용액의 진동수-저장탄성률 곡선의 기울기는 이론적으로 0보다 크고 1.0 이하일 것이 요구된다.When the first binder polymer is prepared as a binder polymer solution containing a solvent and a non-solvent, the horizontal axis is the frequency (rad / s) of the binder polymer solution converted to log scale, and the vertical axis is the logarithmic binder polymer. In the frequency-storage modulus curve, which is the storage modulus of solution (Pa), the slope of the frequency-storage modulus curve of the ideal binder polymer solution is that the first binder polymer should exhibit fast phase separation behavior under humidified phase separation conditions. Theoretically, it is required to be greater than 0 and less than or equal to 1.0.
이러한 제1 바인더 고분자의 비제한적인 예로는 폴리비닐리덴 플루오라이드(polyvinylidene fluoride: PVDF), PVdF-HFP로서 HFP 치환율이 9% 이하인 PVdF-HFP, 공중합체 치환정도가 낮은 PVDF 공중합체 또는 이들의 혼합물 등이 있으나, 이에 한정되는 것은 아니다.Non-limiting examples of such a first binder polymer include polyvinylidene fluoride (PVDF), PVdF-HFP, PVdF-HFP having a HFP substitution rate of 9% or less, a PVDF copolymer having a low degree of copolymer substitution, or a mixture thereof. Etc., but is not limited thereto.
제2 바인더 고분자를 용매 및 비용매와 함께 포함하는 바인더 고분자 용액으로 제조할 경우, 횡축을 로그스케일로 변환된 바인더 고분자 용액의 진동수(rad/s)로 하고, 종축을 로그스케일로 변환된 바인더 고분자 용액의 저장탄성률(Pa)로 하는 진동수-저장탄성률 곡선에 있어서, 상기 제2 바인더 고분자는 가습 상분리 조건에서 느린 상분리 거동을 나타내어야 한다는 점에서, 이상적인 바인더 고분자 용액의 진동수-저장탄성률 곡선의 기울기는 이론적으로 1.0보다 크고 2.0 이하일 것이 요구된다.When preparing the binder polymer solution containing the second binder polymer together with the solvent and the non-solvent, the horizontal axis is the frequency (rad / s) of the binder polymer solution converted to the log scale, and the vertical axis is the logarithmic binder polymer. In the frequency-storage modulus curve, which is the storage modulus of solution (Pa), the slope of the frequency-storage modulus curve of the ideal binder polymer solution is that the second binder polymer should exhibit slow phase separation behavior under humidified phase separation conditions. In theory it is required to be greater than 1.0 and less than or equal to 2.0.
이러한 제2 바인더 고분자의 비제한적인 예로는 PVdF-HFP로서 HFP 치환율이 12% 이상인 PVdF-HFP, PVdF-CTFE, 폴리비닐아세테이트(polyvinylacetate), 시아노에틸풀루란(cyanoethyl pullulan), 시아노에틸폴리비닐알코올(cyanoethyl polyvinylalcohol), 공중합체 치환정도가 높은 PVDF 또는 이들의 혼합물 등이 있으나, 이에 한정되는 것은 아니다.Non-limiting examples of such a second binder polymer is PVdF-HFP, PVdF-HFP, PVdF-CTFE, polyvinylacetate, cyanoethyl pullulan, cyanoethylpolypoly with 12% or more HFP substitution rate Vinyl alcohol (cyanoethyl polyvinylalcohol), PVDF having a high degree of copolymer substitution, or a mixture thereof, but is not limited thereto.
저장탄성률을 강화시키기 위한 방안의 하나로 비용매를 첨가함으로써 저장탄성률을 강화시키는 방법이 있다.One of the ways to enhance the storage modulus is to enhance the storage modulus by adding a non-solvent.
상기 제1 바인더 고분자와 제2 바인더 고분자는 20 : 1 내지 2 : 1의 중량비 조성으로 사용될 수 있다. 제1 바인더 고분자가 상기 상한치보다 많이 사용되는 경우에는 전해액 함침 특성의 개선이 미미해지고, 상기 하한치보다 적게 사용되는 경우에는 상분리가 더디게 일어나서 코팅 생산성이 저하되고 세퍼레이터의 전극접착력이 불충분해질 수 있다.The first binder polymer and the second binder polymer may be used in a weight ratio composition of 20: 1 to 2: 1. When the first binder polymer is used more than the upper limit, the improvement of the electrolyte impregnation characteristics is insignificant, and when the first binder polymer is used less than the lower limit, phase separation may occur slowly, resulting in poor coating productivity and insufficient electrode adhesion of the separator.
본 발명에서 사용될 수 있는 용매는, 아세톤(acetone), 디메틸아세트아미드(dimethyl acetamide, DMAc), 디메틸포름아미드 (dimethylformamide, DMF), 테트라하이드로 퓨란(tetrahydro furan), 메틸렌 클로라이드(methylene chloride, MC), 클로로포름(chloroform), N-메틸-2-피롤리돈(N-methyl-2-pyrrolidone, NMP) 및 시클로헥산(cyclohexane)으로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있으나, 이에만 한정하는 것은 아니다.The solvent that can be used in the present invention, acetone (acetone), dimethyl acetamide (DMAc), dimethylformamide (dimethylformamide, DMF), tetrahydro furan (tetrahydro furan), methylene chloride (MC), It may be any one selected from the group consisting of chloroform, N-methyl-2-pyrrolidone (NMP) and cyclohexane, or a mixture of two or more thereof. It is not limited only to this.
상기 용매는, 그 종류에 따라 최종적으로 제조된 전기화학소자 내에 잔존할 경우, 다양한 부반응을 초래할 수도 있으므로, 전기화학소자의 제조과정에서 제거될 수 있다.The solvent may be removed in the manufacturing process of the electrochemical device, since the solvent may cause various side reactions when remaining in the finally manufactured electrochemical device.
상기 비용매는, 메탄올(methanol), 에탄올(ethanol), 이소프로필알콜(isopropyl alcohol), 부탄올(butanol), 에틸아세테이트(ethyl acetate) 및 물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있 으나, 이에만 한정하는 것은 아니다.The non-solvent may be any one selected from the group consisting of methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate and water, or a mixture of two or more thereof. It is possible, but not limited to.
상기 용매와 비용매의 종류에 따라서, 그 혼합 중량비는 99:1 내지 40:60, 또는 98:2 내지 50:50일 수 있으며, 이러한 혼합 중량비 범위를 만족하는 경우, 바인더 고분자가 다공성 고분자 기재에 스며들어 코팅을 형성할 수 있게 된다.Depending on the type of solvent and non-solvent, the mixing weight ratio may be 99: 1 to 40:60, or 98: 2 to 50:50, and when the mixing weight ratio range is satisfied, the binder polymer may be used in the porous polymer substrate. It can be permeated to form a coating.
한편, 본 발명에 따른 바인더 고분자 용액은 무기물 입자를 더 포함할 수 있다.Meanwhile, the binder polymer solution according to the present invention may further include inorganic particles.
전기화학소자의 안전성 특성에 있어서, 전기화학소자가 과열되어 열폭주가 일어나거나 세퍼레이터가 관통될 경우에는 폭발을 일으키게 될 우려가 크다. 특히, 전기화학소자의 세퍼레이터로서 통상적으로 사용되는 폴리올레핀계 다공성 고분자 기재는 재료적 특성과 연신을 포함하는 제조공정 상의 특성으로 인하여 100 ℃ 이상의 온도에서 극심한 열수축 거동을 보임으로써, 캐소드와 애노드 사이의 단락을 일으킬 수 있다.In the safety characteristics of the electrochemical device, there is a high possibility that an explosion occurs when the electrochemical device is overheated to cause thermal runaway or the separator penetrates. In particular, polyolefin-based porous polymer substrates commonly used as separators for electrochemical devices exhibit extreme heat shrinkage behavior at temperatures of 100 ° C. or higher due to material properties and characteristics of the manufacturing process including stretching, thereby resulting in a short circuit between the cathode and the anode. May cause
이와 같은 전기화학소자의 안전성 문제를 해결하기 위한 방안으로, 바인더 고분자 및 무기물 입자가 혼합된 다공성 코팅층이, 다공성 고분자 기재의 일면 혹은 양면에 형성될 수 있다. 상기 무기물 입자들은 다공성 코팅층의 물리적 형태를 유지할 수 있는 일종의 스페이서(spacer) 역할을 함으로써, 전기화학소자의 과열시 다공성 고분자 기재가 열 수축되는 것을 억제하며, 다공성 고분자 기재가 손상되는 경우에도 캐소드와 애노드가 직접 접촉하는 것을 방지한다.In order to solve the safety problem of the electrochemical device, a porous coating layer in which the binder polymer and the inorganic particles are mixed may be formed on one or both surfaces of the porous polymer substrate. The inorganic particles serve as a kind of spacer that can maintain the physical form of the porous coating layer, thereby suppressing thermal shrinkage of the porous polymer substrate when the electrochemical device is overheated, and the cathode and the anode even when the porous polymer substrate is damaged. To prevent direct contact.
본 발명에 따르면, 이러한 다공성 코팅층은 용매, 비용매, 바인더 고분자 및 무기물 입자를 포함하는 슬러리를, 다공성 고분자 기재에 딥 코팅(dip coating) 방 식으로 코팅한 후, 건조시킴으로써 제조될 수 있다.According to the present invention, such a porous coating layer may be prepared by coating a slurry including a solvent, a non-solvent, a binder polymer and inorganic particles by dip coating on a porous polymer substrate, and then drying.
이 때, 본 발명에서 사용될 수 있는 무기물 입자는 전기화학적으로 안정하기만 하면 특별히 제한되지 않는다. 즉, 본 발명에서 사용할 수 있는 무기물 입자는 적용되는 전기화학소자의 작동 전압 범위(예컨대, Li/Li+ 기준으로 0~5V)에서 산화 및/또는 환원 반응이 일어나지 않는 것이면 특별히 제한되지 않는다. 특히, 무기물 입자로서 유전율이 높은 무기물 입자를 사용하는 경우, 액체 전해질 내 전해질염, 예컨대 리튬염의 해리도 증가에 기여하여 전해액의 이온 전도도를 향상시킬 수 있다.At this time, the inorganic particles that can be used in the present invention is not particularly limited as long as it is electrochemically stable. That is, the inorganic particles that can be used in the present invention are not particularly limited as long as the oxidation and / or reduction reactions do not occur in the operating voltage range (for example, 0 to 5 V on the basis of Li / Li + ) of the applied electrochemical device. In particular, when inorganic particles having a high dielectric constant are used as the inorganic particles, the ionic conductivity of the electrolyte may be improved by contributing to an increase in the dissociation degree of the electrolyte salt such as lithium salt in the liquid electrolyte.
전술한 이유들로 인해, 상기 무기물 입자는 유전율 상수가 5 이상, 또는 10 이상인 고유전율 무기물 입자를 포함할 수 있다. 유전율 상수가 5 이상인 무기물 입자의 비제한적인 예로는 보헤마이트, BaTiO3, Pb(ZrxTi1-x)O3(PZT, 여기서, 0<x<1임), Pb1 - xLaxZr1 - yTiyO3 (PLZT, 여기서, 0<x<1, 0<y<1임), (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT, 여기서, 0<x<1임), 하프니아(HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, SiC 및 TiO2로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물일 수 있다.For the foregoing reasons, the inorganic particles may include high dielectric constant inorganic particles having a dielectric constant of 5 or more, or 10 or more. Non-limiting examples of inorganic particles having a dielectric constant of 5 or more include boehmite, BaTiO 3 , Pb (Zr x Ti 1-x ) O 3 (PZT, where 0 <x <1), Pb 1 - x La x Zr 1 - y Ti y O 3 (PLZT, where 0 <x <1, 0 <y <1), (1-x) Pb (Mg 1/3 Nb 2/3 ) O 3 -xPbTiO 3 (PMN-PT, where 0 <x <1), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , SiC and TiO 2 It may be any one selected or a mixture of two or more thereof.
또한, 리튬 이온 전달 능력을 갖는 무기물 입자, 즉 리튬 원소를 함유하되 리튬을 저장하지 아니하고 리튬 이온을 이동시키는 기능을 갖는 무기물 입자를 사용할 수 있다. 리튬 이온 전달 능력을 갖는 무기물 입자의 비제한적인 예로는 리튬포스페이트(Li3PO4), 리튬티타늄포스페이트(LixTiy(PO4)3, 0 < x < 2, 0 < y < 3), 리튬알루미늄티타늄포스페이트(LixAlyTiz(PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), 14Li2O-9Al2O3-38TiO2-39P2O5 등과 같은 (LiAlTiP)xOy 계열 글래스 (0 < x < 4, 0 < y < 13), 리튬란탄티타네이트(LixLayTiO3, 0 < x < 2, 0 < y < 3), Li3 . 25Ge0 .25P0. 75S4 등과 같은 리튬게르마니움티오포스페이트(LixGeyPzSw, 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), Li3N 등과 같은 리튬나이트라이드(LixNy, 0 < x < 4, 0 < y < 2), Li3PO4-Li2S-SiS2 등과 같은 SiS2 계열 글래스(LixSiySz, 0 < x < 3, 0 < y < 2, 0 < z < 4), LiI-Li2S-P2S5 등과 같은 P2S5 계열 글래스(LixPySz, 0 < x < 3, 0 < y < 3, 0 < z < 7) 또는 이들의 혼합물 등이 있다.In addition, an inorganic particle having lithium ion transfer ability, that is, an inorganic particle containing lithium element but having a function of transferring lithium ions without storing lithium may be used. Non-limiting examples of inorganic particles having a lithium ion transfer capacity include 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) x O y series glasses such as O 5 (0 <x <4, 0 <y <13), lithium lanthanum titanate (Li x La y TiO 3 , 0 <x <2, 0 <y <3) , Li 3 . 25 Ge 0 .25 P 0. 75 S 4 Lithium germanium thiophosphate such as Li x Ge y P z S w , 0 <x <4, 0 <y <1, 0 <z <1, 0 <w <5), Li 3 N, etc. SiS 2 series glasses (Li x Si y S z , 0 <x <3) such as Ride (Li x N y , 0 <x <4, 0 <y <2), Li 3 PO 4 -Li 2 S-SiS 2, etc. , 0 <y <2, 0 <z <4), LiI-Li 2 SP 2 S 5 P 2 S 5 series glass (Li x P y S z , 0 <x <3, 0 <y <3, 0 <z <7), or a mixture thereof.
상기 무기물 입자의 크기는 제한이 없으나, 세퍼레이터의 적절한 공극률을 위해, 평균입도가 0.001㎛ 내지 10㎛ 범위일 수 있다.The size of the inorganic particles is not limited, but for proper porosity of the separator, the average particle size may be in the range of 0.001㎛ to 10㎛.
다공성 코팅층 내의 무기물 입자와 바인더 고분자의 조성비는 예컨대 약 50:50 내지 약 99:1, 또는 약 60:40 내지 약 95:5일 수 있다. 무기물 입자와 바인더 고분자로 구성되는 다공성 코팅층의 두께는 특별한 제한이 없으나, 약 0.01 내지 약 20㎛ 범위일 수 있다. 또한, 기공 크기 및 기공도 역시 특별한 제한이 없으나, 기공 크기는 약 0.01 내지 약 5㎛ 범위이고, 기공도는 약 5 내지 약 75% 범위일 수 있다.The composition ratio of the inorganic particles and the binder polymer in the porous coating layer may be, for example, about 50:50 to about 99: 1, or about 60:40 to about 95: 5. The thickness of the porous coating layer composed of the inorganic particles and the binder polymer is not particularly limited, but may range from about 0.01 to about 20 μm. In addition, the pore size and porosity are also not particularly limited, but the pore size may range from about 0.01 to about 5 μm, and the porosity may range from about 5 to about 75%.
다공성 코팅층의 성분으로서 전술한 무기물 입자 및 바인더 고분자 이외에 당업계에 통상적으로 사용되는 기타 첨가제를 추가로 포함할 수 있다.As the component of the porous coating layer, in addition to the inorganic particles and the binder polymer described above, other additives commonly used in the art may be further included.
상기 다공성 코팅층에서는 바인더 고분자가 무기물 입자들이 서로 결착된 상태를 유지할 수 있도록 이들을 서로 부착(즉, 바인더 고분자가 무기물 입자 사이를 연결 및 고정)시키고 있으며, 또한, 다공성 코팅층은 바인더 고분자에 의해 다공성 고분자 기재와 결착된 상태를 유지한다. 다공성 코팅층의 무기물 입자들에 의한 충진 구조(closed packed or densely packed)에서 실질적으로 면접하는 무기물 입자들에 의해 한정되는 공간인 무기물 입자들간의 인터스티셜 볼륨(interstitial volume)은 다공성 코팅층의 기공이 된다.In the porous coating layer, the binder polymer is attached to each other (that is, the binder polymer is connected and fixed between the inorganic particles) so that the inorganic particles are bound to each other, and the porous coating layer is formed of the porous polymer substrate by the binder polymer. It remains bound with. In the closed packed or densely packed structure of the porous coating layer, the interstitial volume between the inorganic particles, which is a space defined by the inorganic particles that are substantially interviewed, becomes the pores of the porous coating layer. .
다공성 고분자 기재는 통상적으로 전기화학소자에 사용되는 다공성 고분자 기재라면 모두 사용이 가능하고, 예를 들면 폴리올레핀계 다공성 막(membrane) 또는 부직포를 사용할 수 있으나, 이에 특별히 한정되는 것은 아니다.The porous polymer substrate may be used as long as it is a porous polymer substrate commonly used in an electrochemical device. For example, a polyolefin-based porous membrane or a nonwoven fabric may be used, but is not particularly limited thereto.
상기 폴리올레핀계 다공성 막의 비제한적인 예로는, 고밀도 폴리에틸렌, 선형 저밀도 폴리에틸렌, 저밀도 폴리에틸렌, 초고분자량 폴리에틸렌과 같은 폴리에틸렌, 폴리프로필렌, 폴리부틸렌, 폴리펜텐 등의 폴리올레핀계 고분자를 각각 단독으로 또는 이들을 혼합한 고분자로 형성한 막(membrane)을 들 수 있다.Non-limiting examples of the polyolefin-based porous membrane, polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene, ultra high molecular weight polyethylene, respectively, or a mixture thereof And a membrane formed of a polymer.
상기 부직포로는 폴리올레핀계 부직포 외에 예를 들어, 폴리에틸렌테레프탈레이트(polyethyleneterephthalate), 폴리부틸렌테레프탈레이트(polybutyleneterephthalate), 폴리에스테르(polyester), 폴리아세탈(polyacetal), 폴리아미드(polyamide), 폴리카보네이트(polycarbonate), 폴리이미드(polyimide), 폴리에테르에테르케톤(polyetheretherketone), 폴리에테르설 폰(polyethersulfone), 폴리페닐렌옥사이드(polyphenyleneoxide), 폴리페닐렌설파이드(polyphenylenesulfide), 폴리에틸렌나프탈렌(polyethylenenaphthalene) 등을 각각 단독으로 또는 이들을 혼합한 고분자로 형성한 부직포를 들 수 있다. 부직포의 구조는 장섬유로 구성된 스폰본드 부직포 또는 멜트 블로운 부직포일 수 있다.The nonwoven fabric may be, for example, polyethylene terephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, or polycarbonate. ), Polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, polyethylenenaphthalene, etc. Or the nonwoven fabric formed from the polymer which mixed these is mentioned. The structure of the nonwoven can be a spunbond nonwoven or melt blown nonwoven composed of long fibers.
상기 다공성 고분자 기재의 두께는 특별히 제한되지 않으나, 5 내지 50㎛일 수 있고, 다공성 고분자 기재에 존재하는 기공 크기 및 기공도 역시 특별히 제한되지 않으나 각각 0.01 내지 50㎛ 및 10 내지 95%일 수 있다.The thickness of the porous polymer substrate is not particularly limited, but may be 5 to 50 μm, and the pore size and pore present in the porous polymer substrate are also not particularly limited, but may be 0.01 to 50 μm and 10 to 95%, respectively.
상기 바인더 고분자를 포함하는 용액 혹은 상기 바인더 고분자와 무기물 입자를 포함하는 슬러리를 다공성 고분자 기재상에 코팅하는 방법은 당 업계에 알려진 통상적인 코팅 방법을 사용할 수 있으며, 예를 들면 딥(dip) 코팅, 다이(die) 코팅, 롤(roll) 코팅, 콤마(comma) 코팅 또는 이들의 혼합 방식 등 다양한 방식을 이용할 수 있다. 또한, 상기 슬러리는 다공성 고분자 기재의 양면 모두 또는 일면에만 선택적으로 코팅될 수 있다.The method of coating the solution containing the binder polymer or the slurry containing the binder polymer and the inorganic particles on the porous polymer substrate may use a conventional coating method known in the art, for example, dip coating, Various methods may be used, such as die coating, roll coating, comma coating, or a mixture thereof. In addition, the slurry may be selectively coated on both surfaces or only one surface of the porous polymer substrate.
코팅 공정은 일정 범위의 상대 습도에서 실시할 수 있으며, 바람직하게 25 내지 80 ℃의 온도에서 40 내지 80 %의 상대 습도하에서 실시할 수 있다. 코팅 공정시의 온도가 상기 하한치보다 낮으면 다공성 코팅층의 건조가 더디게 이루어지고, 상기 상한치보다 높으면 바인더 고분자의 상분리에 필요한 시간이 부족할 수 있다. 또한, 코팅 공정시의 상대 습도가 상기 하한치보다 낮으면 가습 상분리(vapor-induced phase separation)시 도입되는 비용매인 수분량이 낮아 상분리가 어려우며, 상대 습도가 상기 상한치보다 높으면 건조로 내에서 수분이 응축되는 문제가 발생하게 된다.The coating process can be carried out in a range of relative humidity, preferably at a temperature of 25 to 80 ℃ under a relative humidity of 40 to 80%. When the temperature during the coating process is lower than the lower limit, drying of the porous coating layer is slow, and when the temperature is higher than the upper limit, the time required for phase separation of the binder polymer may be insufficient. In addition, when the relative humidity in the coating process is lower than the lower limit, the amount of moisture, which is a non-solvent introduced during the vapor-induced phase separation, is difficult to separate the phase, and when the relative humidity is higher than the upper limit, moisture is condensed in the drying furnace. Problems will arise.
구체적으로, 용액/슬러리의 코팅 후, 건조 과정을 거치면서 용액/슬러리에 용해되어 있는 제1 바인더 고분자와 제2 바인더 고분자는 당업계에 공지되어 있는 가습 상분리 현상에 의해 상이한 상전이 특성을 갖게 된다. 진동수-저장 탄성률 곡선의 기울기가 1.0 보다 크고 2.0 이하가 되도록 하는 바인더 고분자는 동일한 비용매 하에서 느린 상분리 속도를 갖게 되고, 상분리에 필요한 비용매의 양이 상대적으로 많이 필요하다. 또한, 코팅후 다공성 코팅층의 두께 방향의 전반에 존재하거나 다공성 고분자 기재 내부로 침투할 수 있다. 또한, 진동수-저장 탄성률 곡선의 기울기가 0 보다 크고 1.0 이하가 되도록 하는 바인더 고분자는 빠른 상분리 속도를 갖고, 상분리에 필요한 비용매의 양을 적게 필요로 하며, 세퍼레이터 표면에 집중적으로 존재하게 된다. 따라서, 본 발명의 일 실시양태에 따르면, 바인더 고분자 중 일부는 세퍼레이터 표면에 집중적으로 분포하여 전극과 우수한 접착력을 나타내고, 다른 바인더 고분자는 다공성 고분자 기재에 침투하여 코팅을 형성하면서 다공성 고분자 기재가 우수한 전해액 함침성을 나타내도록 한다.Specifically, after coating the solution / slurry, the first binder polymer and the second binder polymer dissolved in the solution / slurry during the drying process have different phase transition characteristics by humidifying phase separation phenomenon known in the art. Binder polymers having a slope of the frequency-storage modulus curve greater than 1.0 and less than or equal to 2.0 have a slow phase separation rate under the same nonsolvent, and require a relatively large amount of nonsolvent required for phase separation. In addition, it may exist in the first half of the thickness direction of the porous coating layer after coating or penetrate into the porous polymer substrate. In addition, the binder polymer which makes the slope of the frequency-storage modulus curve greater than 0 and equal to or less than 1.0 has a high phase separation speed, requires a small amount of nonsolvent required for phase separation, and concentrates on the separator surface. Therefore, according to one embodiment of the present invention, some of the binder polymers are intensively distributed on the surface of the separator and exhibit excellent adhesion with the electrode, while the other binder polymer penetrates into the porous polymer substrate to form a coating and has an excellent electrolyte solution of the porous polymer substrate. Show impregnation.
이어서 수행되는 건조 공정은 당업계에 공지되어 있는 방법으로 실시될 수 있으며, 사용된 용매의 증기압을 고려한 온도 범위에서 오븐 또는 가열식 챔버를 사용하여 배치식 또는 연속식으로 가능하다. 상기 건조는 상기 슬러리 내에 존재하는 용매를 거의 제거하는 것이며, 이는 생산성 등을 고려하여 가능한 빠른 것이 바람직하며, 예컨대 1분 이하, 바람직하게는 30초 이하의 시간 동안 실시될 수 있다.The drying process carried out subsequently may be carried out by methods known in the art and may be batchwise or continuously using an oven or heated chamber in a temperature range that takes into account the vapor pressure of the solvent used. The drying is to almost eliminate the solvent present in the slurry, which is preferably as fast as possible in view of productivity and the like, for example, may be carried out for a time of 1 minute or less, preferably 30 seconds or less.
한편, 본 발명의 일 측면에 따른 전기화학소자는, 캐소드, 애노드, 및 상기 캐소드와 애노드 사이에 개재된 세퍼레이터를 포함하며, 상기 세퍼레이터는 전술한 본 발명의 세퍼레이터이다.Meanwhile, an electrochemical device according to an aspect of the present invention includes a cathode, an anode, and a separator interposed between the cathode and the anode, wherein the separator is the separator of the present invention described above.
본 발명의 일 실시예에 따른 전기화학소자는 전기 화학 반응을 하는 모든 소자를 포함하며, 구체적인 예를 들면, 모든 종류의 1차, 이차 전지, 연료 전지, 태양 전지 또는 슈퍼 커패시터 소자와 같은 커패시터(capacitor) 등이 있다. 특히, 상기 이차 전지 중 리튬 금속 이차 전지, 리튬 이온 이차 전지, 리튬 폴리머 이차전지 또는 리튬 이온 폴리머 이차 전지 등을 포함하는 리튬 이차전지가 바람직하다.The electrochemical device according to an embodiment of the present invention includes all devices that undergo an electrochemical reaction, and specific examples include capacitors such as all kinds of primary, secondary, fuel cell, solar cell, or super capacitor devices. capacitor). 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 among the secondary batteries is preferable.
본 발명의 일 실시예에 따른 전기화학소자에 적용될 전극으로는 특별히 제한되지 않으며, 당업계에 알려진 통상적인 방법에 따라 전극 활물질을 전극 전류집전체에 결착된 형태로 제조할 수 있다.The electrode to be applied to the electrochemical device according to an embodiment of the present invention is not particularly limited, and according to a conventional method known in the art, the electrode active material may be manufactured in a form bound to the electrode current collector.
상기 전극 활물질 중 캐소드 활물질의 비제한적인 예로는 종래 전기화학소자의 캐소드에 사용될 수 있는 통상적인 캐소드 활물질이 사용 가능하며, 특히 리튬망간 산화물, 리튬코발트 산화물, 리튬니켈 산화물, 리튬철 산화물 또는 이들을 조합한 리튬복합 산화물을 사용할 수 있다. 애노드 활물질의 비제한적인 예로는 종래 전기화학소자의 애노드에 사용될 수 있는 통상적인 애노드 활물질이 사용 가능하며, 특히 리튬 금속 또는 리튬 합금, 탄소, 석유코크(petroleum coke), 활성화 탄소(activated carbon), 그래파이트(graphite) 또는 기타 탄소류 등과 같은 리튬흡착물질 등이 바람직하다. 캐소드 전류집전체의 비제한적인 예로는 알루미늄, 니켈 또는 이들의 조합에 의하여 제조되는 호일 등이 있으며, 애노드 전류집전체의 비제한적인 예로는 구리, 금, 니켈 또는 구리 합금 또는 이들의 조합에 의하여 제조되는 호일 등이 있다.Non-limiting examples of the cathode active material of the electrode active material may be a conventional cathode active material that can be used for the cathode of the conventional electrochemical device, in particular lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide or a combination thereof One lithium composite oxide can be used. Non-limiting examples of the anode active material may be a conventional anode active material that can be used in the anode of the conventional electrochemical device, in particular lithium metal or lithium alloys, carbon, petroleum coke, activated carbon, Lithium adsorption materials such as graphite or other carbons are preferable. Non-limiting examples of the cathode current collector is a foil made by aluminum, nickel or a combination thereof, and non-limiting examples of the anode current collector by copper, gold, nickel or a copper alloy or a combination thereof. Foils produced.
본 발명의 일 실시예에서 사용될 수 있는 비수 전해액에 포함되는 전해질 염은 리튬염이다. 상기 리튬염은 리튬 이차전지용 전해액에 통상적으로 사용되는 것들이 제한 없이 사용될 수 있다. 예를 들어 상기 리튬염의 음이온으로는 F-, Cl-, Br-, I-, NO3 -, N(CN)2 -, BF4 -, ClO4 -, PF6 -, (CF3)2PF4 -, (CF3)3PF3 -, (CF3)4PF2 -, (CF3)5PF-, (CF3)6P-, CF3SO3 -, CF3CF2SO3 -, (CF3SO2)2N-, (FSO2)2N- , CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (CF3SO2)3C-, CF3(CF2)7SO3 -, CF3CO2 -, CH3CO2 -, SCN- 및 (CF3CF2SO2)2N-로 이루어진 군에서 선택된 어느 하나일 수 있다.The electrolyte salt included in the nonaqueous electrolyte solution which can be used in one embodiment of the present invention is a lithium salt. The lithium salt may be used without limitation those conventionally used in the lithium secondary battery electrolyte. For example is the above lithium salt anion F -, Cl -, Br - , I -, NO 3 -, N (CN) 2 -, BF 4 -, ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P -, CF 3 SO 3 -, CF 3 CF 2 SO 3 - , (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, ( CF 3 SO 2) 3 C - , CF 3 (CF 2) 7 SO 3 -, CF 3 CO 2 -, CH 3 CO 2 -, SCN - and (CF 3 CF 2 SO 2 ) 2 N -It may be any one selected from the group consisting of.
전술한 비수 전해액에 포함되는 유기용매로는 리튬 이차전지용 전해액에 통상적으로 사용되는 것들을 제한없이 사용할 수 있으며, 예를 들면 에테르, 에스테르, 아미드, 선형 카보네이트, 환형 카보네이트 등을 각각 단독으로 또는 2종 이상 혼합하여 사용할 수 있다.As the organic solvent included in the non-aqueous electrolyte solution, those conventionally used in the lithium secondary battery electrolyte solution can be used without limitation. For example, ethers, esters, amides, linear carbonates, cyclic carbonates, and the like can be used alone or in combination of two or more. It can be mixed and used.
그 중에서 대표적으로는 환형 카보네이트, 선형 카보네이트, 또는 이들의 혼합물인 카보네이트 화합물을 포함할 수 있다.Among them, carbonate compounds which are typically cyclic carbonates, linear carbonates, or mixtures thereof may be included.
상기 환형 카보네이트 화합물의 구체적인 예로는 에틸렌 카보네이트(ethylene carbonate, EC), 프로필렌 카보네이트(propylene carbonate, PC), 1,2-부틸렌 카보네이트, 2,3-부틸렌 카보네이트, 1,2-펜틸렌 카보네이트, 2,3-펜틸렌 카보네이트, 비닐렌 카보네이트, 비닐에틸렌 카보네이트 및 이들의 할로겐화물로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물이 있다.Specific examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, vinylethylene carbonate and any one selected from the group consisting of halides thereof or mixtures of two or more thereof.
이들의 할로겐화물로는 예를 들면, 플루오로에틸렌 카보네이트(fluoroethylene carbonate, FEC) 등이 있으며, 이에 한정되는 것은 아니다.These halides include, for example, fluoroethylene carbonate (FEC), but are not limited thereto.
또한 상기 선형 카보네이트 화합물의 구체적인 예로는 디메틸 카보네이트(DMC), 디에틸 카보네이트(DEC), 디프로필 카보네이트(DPC), 에틸메틸 카보네이트(EMC), 메틸프로필 카보네이트 및 에틸프로필 카보네이트로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물 등이 대표적으로 사용될 수 있으나, 이에 한정되는 것은 아니다.In addition, specific examples of the linear carbonate compounds include any one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate. One or a mixture of two or more thereof may be representatively used, but is not limited thereto.
특히, 상기 카보네이트계 유기용매 중 환형 카보네이트인 에틸렌 카보네이트 및 프로필렌 카보네이트는 고점도의 유기용매로서 유전율이 높아 전해질 내의 리튬염을 보다 더 잘 해리시킬 수 있으며, 이러한 환형 카보네이트에 디메틸 카보네이트 및 디에틸 카보네이트와 같은 저점도, 저유전율 선형 카보네이트를 적당한 비율로 혼합하여 사용하면 보다 높은 전기 전도율을 갖는 전해액을 만들 수 있다.In particular, ethylene carbonate and propylene carbonate, which are cyclic carbonates among the carbonate-based organic solvents, are high viscosity organic solvents and have a high dielectric constant, which may dissociate lithium salts in the electrolyte more effectively. By using a low viscosity, low dielectric constant linear carbonate mixed in an appropriate ratio it can be made an electrolyte having a higher electrical conductivity.
상기 유기용매 중 에테르로는 디메틸 에테르, 디에틸 에테르, 디프로필 에테르, 메틸에틸 에테르, 메틸프로필 에테르 및 에틸프로필 에테르로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물을 사용할 수 있으나, 이에 한정되는 것은 아니다.In the organic solvent, any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methylethyl ether, methylpropyl ether, and ethylpropyl ether, or a mixture of two or more thereof may be used. It is not limited.
상기 유기용매 중 에스테르로는 메틸 아세테이트, 에틸 아세테이트, 프로필 아세테이트, 메틸 프로피오네이트, 에틸 프로피오네이트, γ-부티로락톤, γ-발레로락톤, γ-카프로락톤, σ-발레로락톤 및 ε-카프로락톤으로 이루어진 군에서 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물을 사용할 수 있으나, 이에 한정되는 것은 아니다.Ester in the organic solvent is methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone and ε Any one or a mixture of two or more selected from the group consisting of caprolactone may be used, but is not limited thereto.
상기 비수 전해액의 주입은 최종 제품의 제조 공정 및 요구 물성에 따라, 전기화학소자의 제조 공정 중 적절한 단계에서 행해질 수 있다. 즉, 전기화학소자 조립 전 또는 전기화학소자 조립 최종 단계 등에서 적용될 수 있다.The injection of the nonaqueous electrolyte may be performed at an appropriate step in the manufacturing process of the electrochemical device, depending on the manufacturing process and the required physical properties of the final product. That is, it may be applied before the electrochemical device assembly or the final step of the electrochemical device assembly.
본 발명에 따른 전기화학소자는, 일반적인 공정인 권취(winding) 이외에도 세퍼레이터와 전극의 적층(lamination, stack) 및 접음(folding) 공정이 가능하다.The electrochemical device according to the present invention, in addition to the winding (winding) which is a general process, the lamination (stacking) and folding (folding) process of the separator and the electrode is possible.
그리고, 전기화학소자의 외형은 특별한 제한이 없으나, 캔을 사용한 원통형, 각형, 파우치(pouch)형 또는 코인(coin)형 등이 될 수 있다.The external shape of the electrochemical device is not particularly limited, but may be cylindrical, square, pouch or coin type using a can.
이하, 본 발명을 구체적으로 설명하기 위해 실시예를 들어 상세하게 설명하기로 한다. 그러나, 본 발명에 따른 실시예는 여러 가지 다른 형태로 변형될 수 있으며, 본 발명의 범위가 아래에서 상술하는 실시예에 한정되는 것으로 해석되어서는 아니 된다. 본 발명의 실시예는 당업계에서 평균적인 지식을 가진 자에게 본 발명을 보다 완전하게 설명하기 위해서 제공되는 것이다.Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in various other forms, the scope of the present invention should not be construed as limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.
실시예Example 1:  One: 세퍼레이터의Separator 제조 Produce
용매로서 아세톤 100 중량부 및 비용매로서 메탄올 30 중량부를 혼합한 혼합물에, 제1 바인더 고분자로 폴리비닐리덴 플루오라이드(LBG, Arkema社, HFP 함량 5%) 3 중량부와 폴리비닐리덴 플루오라이드 (Kynar2500, Arkema社, HFP 함량 20%) 0.3 중량부를 첨가하여 50℃에서 약 12시간 이상 용해시켜 바인더 고분자 용액을 제조하였다. 상기 용액 80 중량부에 500 nm 급 알루미나(AES11, Sumitomo社) 20 중량부를 혼합하여, 다공성 코팅층 형성을 위한 슬러리를 제조하였다. 상기 슬러리를 딥(dip) 코팅법으로, 두께 7㎛인 폴리에틸렌 다공성 막(ND307B, Asahi社)의 양면에 코팅하여 다공성 코팅층을 형성시켜서 세퍼레이터를 제조하였다. 다공성 코팅층의 두께는 약 4㎛ 정도로 조절하였다.In a mixture of 100 parts by weight of acetone as a solvent and 30 parts by weight of methanol as a solvent, 3 parts by weight of polyvinylidene fluoride (LBG, Arkema, HFP content 5%) and polyvinylidene fluoride ( Kynar2500, Arkema, HFP content 20%) 0.3 parts by weight was added to dissolve at 50 ℃ or more for about 12 hours to prepare a binder polymer solution. 20 parts by weight of 500 nm alumina (AES11, Sumitomo) was mixed with 80 parts by weight of the solution to prepare a slurry for forming a porous coating layer. The slurry was coated on both sides of a polyethylene porous membrane (ND307B, Asahi Co., Ltd.) having a thickness of 7 μm by dip coating to form a porous coating layer. The thickness of the porous coating layer was adjusted to about 4㎛.
비교예Comparative example 1:  One: 세퍼레이터의Separator 제조 Produce
바인더 고분자로서 폴리비닐리덴 플루오라이드(LBG, Arkema社, HFP 함량 5%) 3.3 중량부를 단독으로 사용하는 것을 제외하고 실시예 1과 동일한 방법으로 세퍼레이터를 제조하였다.A separator was prepared in the same manner as in Example 1, except that 3.3 parts by weight of polyvinylidene fluoride (LBG, Arkema, HFP content 5%) was used alone.
비교예Comparative example 2:  2: 세퍼레이터의Separator 제조 Produce
바인더 고분자로서 입자형 수분산 에멀전 바인더 고분자인 아크릴계 공중합체 (CSB130, Toyo ink 社) 1.0 중량부를 사용하고 용매로 물을 사용하는 것을 제외하고 실시예 1과 동일한 방법으로 세퍼레이터를 제조하였다.A separator was prepared in the same manner as in Example 1, except that 1.0 parts by weight of an acrylic copolymer (CSB130, Toyo ink Co., Ltd.), a particulate water-dispersible emulsion binder polymer, was used as the binder polymer and water was used as the solvent.
평가예Evaluation example
실시예 1 및 비교예 1과 2에서 제조한 세퍼레이터 각각에 형성된 다공성 코 팅층에 테이프(3M 투명 테이프)를 부착시킨 후, 상기 테이프를 제거함으로써 다공성 코팅층을 세퍼레이터로부터 분리시켰다. 코팅층이 제거된 세퍼레이터를 ATR 위에 거치하고, 세퍼레이터 일면 상부에서 프로필렌 카보네이트 용매를 50 uL 점적(drop)하였다. 프로필렌 카보네이트는 세퍼레이터 두께 방향으로 침투하여 점적한 면의 반대면으로 침투하고, 이를 ATR 상 C=O 피크(peak)의 크기를 시간에 따라 관찰하여, 피크의 크기가 임계점에 도달하는 시점까지 소요되는 시간을 측정하고 그 결과를 하기 표 1에 기재하였다.After attaching a tape (3M transparent tape) to the porous coating layer formed on each of the separators prepared in Example 1 and Comparative Examples 1 and 2, the porous coating layer was separated from the separator by removing the tape. The separator from which the coating layer was removed was mounted on the ATR, and 50 uL of propylene carbonate solvent was dropped on the upper surface of the separator. Propylene carbonate penetrates in the thickness direction of the separator and penetrates to the opposite side of the dripping surface, and observes the magnitude of the C = O peak on the ATR over time, and it takes time until the peak reaches the critical point. The time was measured and the results are shown in Table 1 below.
실시예 1Example 1 비교예 1Comparative Example 1 비교예 2Comparative Example 2
소요 시간(sec)Time required (sec) 1.051.05 6.056.05 12.3012.30

Claims (12)

  1. 다수의 기공을 갖는 다공성 고분자 기재; 및Porous polymer substrate having a plurality of pores; And
    제1 바인더 고분자와 제2 바인더 고분자를 포함하는 바인더 고분자 용액으로부터 형성되어 상기 다공성 고분자 기재의 적어도 일면에 형성된 층을 구비하며,A layer formed from a binder polymer solution including a first binder polymer and a second binder polymer and formed on at least one surface of the porous polymer substrate,
    이 때, 횡축은 로그스케일로 변환된 진동수(rad/s)로 하고 종축은 로그스케일로 변환된 저장탄성률(MPa)로 하는 진동수-저장 탄성률 곡선에 있어서, 상기 진동수가 0.01 내지 10 rad/s를 나타내는 범위에서, 상기 제1 바인더 고분자는 메탄올 30중량%를 포함하는 용매 중에 3중량% 농도로 첨가되었을 때 진동수-저장 탄성률 곡선의 기울기가 0보다 크고 1.0 이하이고, 상기 제2 바인더 고분자는 메탄올 30중량%를 포함하는 용매 중에 3중량% 농도로 첨가되었을 때 진동수-저장 탄성률 곡선의 기울기가 1.0보다 크고 2.0 이하인 것을 특징으로 하는In the frequency-storage modulus curve where the abscissa is the log scale-converted frequency (rad / s) and the ordinate is the log-scale storage modulus (MPa), the frequency is 0.01-10 rad / s. In the range shown, the slope of the frequency-storage modulus curve is greater than 0 and less than or equal to 1.0 when the first binder polymer is added at a concentration of 3% by weight in a solvent containing 30% by weight of methanol, and the second binder polymer is methanol 30 Characterized in that the slope of the frequency-storage modulus curve is greater than 1.0 and less than or equal to 2.0 when added at a concentration of 3% by weight in a solvent comprising
    전기화학소자용 세퍼레이터.Separators for electrochemical devices.
  2. 제1항에 있어서,The method of claim 1,
    상기 제1 바인더 고분자와 제2 바인더 고분자는 20 : 1 내지 2 : 1의 중량비 조성으로 사용되는 것을 특징으로 하는 전기화학소자용 세퍼레이터.The first binder polymer and the second binder polymer is an electrochemical device separator, characterized in that used in a weight ratio composition of 20: 1 to 2: 1.
  3. 제1항에 있어서,The method of claim 1,
    상기 제1 바인더 고분자가 폴리비닐리덴 플루오라이드(polyvinylidene fluoride: PVDF), PVdF-HFP로서 HFP 치환율이 9% 이하인 PVdF-HFP 또는 이들의 혼합물이고, 상기 제2 바인더 고분자가 HFP 치환율이 12% 이상인 PVdF-HFP, PVdF-CTFE, 폴리비닐아세테이트(polyvinylacetate), 시아노에틸풀루란(cyanoethyl pullulan), 시아노에틸폴리비닐알코올(cyanoethyl polyvinylalcohol) 또는 이들의 혼합물인 것을 특징으로 하는 전기화학소자용 세퍼레이터.The first binder polymer is polyvinylidene fluoride (PVDF), PVdF-HFP, PVdF-HFP having a HFP substitution rate of 9% or less, or a mixture thereof, and the second binder polymer is PVdF having a HFP substitution rate of 12% or more. Separator for an electrochemical device, characterized in that HFP, PVdF-CTFE, polyvinylacetate, cyanoethyl pullulan, cyanoethyl polyvinylalcohol or a mixture thereof.
  4. 제1항에 있어서,The method of claim 1,
    상기 제1 바인더 고분자와 제2 바인더 고분자를 포함하여 이루어진 층에 무기물 입자가 더 포함되어 있는 것을 특징으로 하는 전기화학소자용 세퍼레이터.Separator for an electrochemical device, characterized in that the inorganic particles are further included in the layer comprising the first binder polymer and the second binder polymer.
  5. 제1항에 있어서,The method of claim 1,
    상기 무기물 입자는 유전율 상수가 약 5 이상인 무기물 입자, 리튬 이온 전달 능력을 갖는 무기물 입자, 또는 이들의 혼합물인 것을 특징으로 하는 전기화학소자용 세퍼레이터.The inorganic particles are inorganic particles having a dielectric constant of about 5 or more, inorganic particles having lithium ion transfer ability, or a mixture thereof.
  6. 제5항에 있어서,The method of claim 5,
    상기 유전율 상수가 약 5 이상인 무기물 입자는 보헤마이트, BaTiO3, Pb(ZrxTi1-x)O3(PZT, 여기서, 0<x<1임), Pb1 - xLaxZr1 - yTiyO3 (PLZT, 여기서, 0<x<1, 0<y<1임), (1-x)PB(Mg1/3Nb2/3)O3-xPbTiO3(PMN-PT, 여기서 0 < x < 1), 하프니아(HfO2), SrTiO3, SnO2, CeO2, MgO, NiO, CaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2 및 SiC로 이루어진 군으로부터 선택되는 어느 하나 또는 이들중 2종 이상의 혼합물인 것을 특징으로 하는 전기화학소자용 세퍼레이터.The dielectric constant of about 5 or more inorganic particles are boehmite, BaTiO 3, Pb (Zr x Ti 1-x) O 3 (PZT, where, 0 <x <1 Im), Pb 1 - x La x Zr 1 - y Ti y O 3 (PLZT, where 0 <x <1, 0 <y <1), (1-x) PB (Mg 1/3 Nb 2/3 ) O 3 -xPbTiO 3 (PMN-PT, where 0 <x < 1), hafnia (HfO 2 ), SrTiO 3 , SnO 2 , CeO 2 , MgO, NiO, CaO, ZnO, ZrO 2 , Y 2 O 3 , Al 2 O 3 , TiO 2 and SiC Separators for any one or a mixture of two or more thereof.
  7. 제5항에 있어서,The method of claim 5,
    상기 리튬 이온 전달 능력을 갖는 무기물 입자는 리튬포스페이트(Li3PO4), 리튬티타늄포스페이트(LixTiy(PO4)3, 0 < x < 2, 0 < y < 3), 리튬알루미늄티타늄포스페이트(LixAlyTiz(PO4)3, 0 < x < 2, 0 < y < 1, 0 < z < 3), (LiAlTiP)xOy 계열 glass (0 < x < 4, 0 < y < 13), 리튬란탄티타네이트(LixLayTiO3, 0 < x < 2, 0 <y < 3), 리튬게르마니움티오포스페이트(LixGeyPzSw, 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), 리튬나이트라이드(LixNy, 0 < x < 4, 0 < y < 2), SiS2 계열 glass(LixSiySz, 0 < x < 3, 0 < y < 2, 0 < z < 4) 및 P2S5 계열 glass(LixPySz, 0 < x < 3, 0 < y < 3, 0 < z < 7)로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물인 것을 특징으로 하는 전기화학소자용 세퍼레이터.The inorganic particles having a lithium ion transfer ability include lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li x Ti y (PO 4 ) 3 , 0 <x <2, 0 <y <3), and lithium aluminum titanium phosphate (Li x Al y Ti z (PO 4 ) 3 , 0 <x <2, 0 <y <1, 0 <z <3), (LiAlTiP) x O y series glass (0 <x <4, 0 <y <13), lithium lanthanum titanate (Li x La y TiO 3 , 0 <x <2, 0 <y <3), lithium germanium thiophosphate (Li x Ge y P z S w , 0 <x <4 , 0 <y <1, 0 <z <1, 0 <w <5), lithium nitride (Li x N y , 0 <x <4, 0 <y <2), SiS 2 series glass (Li x Si y S z , 0 <x <3, 0 <y <2, 0 <z <4) and P 2 S 5 series glass (Li x P y S z , 0 <x <3, 0 <y <3, 0 <z <7) any one selected from the group consisting of or a mixture of two or more thereof.
  8. (S1) 다수의 기공을 갖는 다공성 고분자 기재를 준비하는 단계;(S1) preparing a porous polymer substrate having a plurality of pores;
    (S2) 제1 바인더 고분자와 제2 바인더 고분자, 상기 바인더 고분자 둘다를 용해시키는 용매, 및 상기 바인더 고분자 둘다를 용해시키지 않는 비용매를 포함하는 바인더 고분자 용액을 준비하는 단계; 및(S2) preparing a binder polymer solution including a first binder polymer and a second binder polymer, a solvent for dissolving both of the binder polymers, and a non-solvent not dissolving both of the binder polymers; And
    (S3) 상기 바인더 고분자 용액을 다공성 고분자 기재의 적어도 일면에 코팅하고, 가습 조건에서 상분리시키는 단계;를 포함하는(S3) coating the binder polymer solution on at least one surface of the porous polymer substrate, and performing phase separation in a humidified condition;
    제1항에 기재된 전기화학소자용 세퍼레이터의 제조방법.The manufacturing method of the separator for electrochemical elements of Claim 1.
  9. 제8항에 있어서,The method of claim 8,
    상기 용매는 아세톤(acetone), 디메틸아세트아미드(dimethyl acetamide, DMAc), 디메틸포름아미드(dimethyl formamide, DMF), 테트라하이드로퓨란(tetrahydro furane), 메틸렌 클로라이드(methylene chloride, MC), 클로로포름(chloroform), N-메틸-2-피롤리돈(N-methyl-2-pyrrolidone, NMP) 및 시클로헥산(cyclohexane)으로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물인 것을 특징으로 하는 전기화학소자용 세퍼레이터의 제조방법.The solvent may be acetone, dimethyl acetamide (DMAc), dimethyl formamide (DMF), tetrahydrofurane, methylene chloride (MC), chloroform, N-methyl-2-pyrrolidone (N-methyl-2-pyrrolidone, NMP) and cyclohexane (cyclohexane) is selected from the group consisting of any one or a mixture of two or more thereof Method for producing a separator.
  10. 제8항에 있어서,The method of claim 8,
    상기 비용매는 메탄올(methanol), 에탄올(ethanol), 이소프로필 알콜(isopropyl alcohol), 부탄올(butanol), 에틸아세테이트(ethyl acetate) 및 물로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 혼합물인 것을 특징으로 하는 전기화학소자용 세퍼레이터의 제조방법.The non-solvent is any one selected from the group consisting of methanol, ethanol, isopropyl alcohol, butanol, ethyl acetate and water or a mixture of two or more thereof. A method of manufacturing a separator for an electrochemical device, characterized in that.
  11. 제8항에 있어서,The method of claim 8,
    상기 용매와 비용매의 중량비는 98:2 내지 50:50인 것을 특징으로 하는 전기화학소자용 세퍼레이터의 제조방법.The weight ratio of the solvent and the non-solvent is 98: 2 to 50:50 method for producing a separator for an electrochemical device.
  12. 제8항에 있어서,The method of claim 8,
    상기 가습 조건은 25 내지 80 ℃의 온도에서 40 내지 80 %의 상대 습도 조건인 것을 특징으로 하는 전기화학소자용 세퍼레이터의 제조방법.The humidification condition is a method for manufacturing a separator for an electrochemical device, characterized in that the relative humidity conditions of 40 to 80% at a temperature of 25 to 80 ℃.
PCT/KR2016/004522 2015-04-30 2016-04-29 Separator for electrochemical element having improved electrolyte wettability and electrochemical element comprising same separator WO2016175605A1 (en)

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