KR20190036627A - The Method For Treating Surface Of Battery Separator - Google Patents

Abstract

The present invention relates to a separation membrane surface treatment method for increasing adhesiveness between a separation membrane and an electrode and impregnability of an electrolyte solution. According to an embodiment of the present invention, the separation membrane surface treatment method comprises the steps of: forming a porous coating layer on a porous polymer substrate to manufacture a separation membrane; allowing a UV lamp to irradiate ultraviolet rays to a space in which the separation membrane is disposed; reacting the ultraviolet rays with oxygen present in the air to generate ozone; and allowing the ozone to oxidize a surface of the separation membrane.

Description

[0001] The present invention relates to a method for treating a surface of a membrane,

The present invention relates to a separation membrane surface treatment method, and more particularly, to a separation membrane surface treatment method for improving the adhesion between a separation membrane and an electrode and impregnability of an electrolyte solution.

Cells and batteries that generate electrical energy through the physical reaction or chemical reaction of a material and supply power to the outside can not acquire the AC power supplied to the building depending on the living environment surrounded by various electronic devices It is used when DC power is needed.

Among such cells, a primary cell and a secondary cell, which are chemical cells using a chemical reaction, are generally used. A primary cell is a consumable cell which is collectively referred to as a dry cell. On the other hand, a secondary battery is a rechargeable battery in which oxidation and reduction processes between an electric current and a substance are manufactured using a plurality of repeatable materials. That is, when the reduction reaction is performed on the workpiece by the current, the power source is charged. When the oxidation reaction is performed on the workpiece, the power source is discharged. Such charge-discharge is repeatedly performed to generate electricity.

In general, the secondary battery includes a nickel cadmium battery, a nickel metal hydride battery, a lithium ion battery, and a lithium ion polymer battery. Such a secondary battery is not limited to small-sized products such as a digital camera, a P-DVD, an MP3P, a mobile phone, a PDA, a portable game device, a power tool and an e-bike, It is also applied to power storage devices that store power and renewable energy, and backup power storage devices.

The lithium secondary battery is generally formed by stacking a cathode, a separator, and an anode. These materials are selected in consideration of battery life, charge / discharge capacity, temperature characteristics, stability, and the like. The charging and discharging of the lithium secondary battery proceeds as the lithium ion is intercalated and deintercalated from the lithium metal oxide in the anode to the graphite electrode in the cathode.

In general, unit cells stacked in a three-layer structure of a cathode / separator / cathode or a five-layer structure of anode / separator / cathode / separator / anode or cathode / separator / anode / separator / cathode are gathered to be one electrode assembly . Such an electrode assembly is accommodated in a specific case.

Conventionally, a corona discharge treatment or a plasma treatment was performed to improve the adhesion between the electrode and the electrode before the electrode is laminated after the slurry is applied to the porous substrate in the process of manufacturing the separator.

1 is a schematic view showing a state in which a general separation membrane 2 is subjected to a corona discharge treatment.

Corona discharge is a phenomenon that when the DC power is increased by using the conductor as an electrode and the opposite electrode as a metal plate, the electrode turns purple and current flows. When the separator 2 is positioned between the corona electrode 20 and the ground electrode 21 and subjected to a corona discharge treatment, particles 22 of electrons and ions are accelerated and moved due to a high potential difference between the electrodes. At this time, the particles 22 were rapidly moved toward the separation membrane 2, and the separation membrane 2 was physically damaged. Therefore, the contact area with the electrode is increased, and the adhesion of the separation membrane 2 can be improved. On the other hand, there is a problem that the impregnation property of the electrolyte impregnated between the separator 2 and the contact interface between the electrodes is lowered due to such physical damage.

Korea Patent No. 10-1457546 Korean Laid-Open Publication No. 10-2015-0049481

A problem to be solved by the present invention is to provide a separation membrane surface treatment method which improves the adhesion between the separation membrane and the electrode and the impregnability of the electrolyte solution.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a separation membrane surface treatment method comprising the steps of: preparing a separation membrane by forming a porous coating layer on a porous polymer substrate; Irradiating ultraviolet rays to the space in which the separation membrane is disposed; Reacting the ultraviolet ray with oxygen present in the air to generate ozone; And the ozone oxidizing the surface of the separation membrane.

Further, in the step of generating ozone, the concentration measuring device may further include measuring the concentration of oxygen or ozone present in the air.

Further, when the oxygen concentration is insufficient, the oxygen generator can further supply oxygen.

In addition, when the concentration of ozone measured by the concentration meter is different from the predetermined ozone concentration, the control unit may apply an ultraviolet emission amount adjustment signal to the UV lamp.

The porous polymer substrate may be a porous polymer film substrate or a porous polymer nonwoven substrate.

The porous polymer film substrate may be a polyolefin-based porous polymer film substrate.

The polyolefin-based porous polymer film base may be formed of one or more selected from the group consisting of polyethylene, polypropylene, polybutylene, and polypentene.

The porous polymeric nonwoven substrate may be formed of at least one selected from the group consisting of a polyolefin polymer, a polyethylene terephthalate, a polybutylene terephthalate, a polyester, a polyacetal, a polyamide, a polycarbonate Polyether sulfone, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyether sulfone One or more selected from the group consisting of polyether sulfone, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylene naphthalene. have.

The thickness of the porous polymer base material may be 5 to 50 탆.

The pore size of the porous polymer substrate may be 0.01 to 50 탆.

The porosity of the porous polymer substrate may be 10 to 95%.

The porous coating layer may be formed by coating a slurry containing a mixture of inorganic particles and a polymeric binder by a dip coating method.

The average particle diameter of the inorganic particles may be 0.001 to 10 mu m.

The inorganic particles may be formed of one or more selected from the group consisting of inorganic particles having a dielectric constant of 5 or more and inorganic particles having lithium ion transporting ability.

In addition, the polymer binder may include PVDF-HFP.

Other specific details of the invention are included in the detailed description and drawings.

The embodiments of the present invention have at least the following effects.

It is possible to improve the adhesiveness of the separator and the electrode and the impregnation of the electrolyte by using only the chemical treatment method without physically damaging the separator without using the existing corona treatment method.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.

1 is a schematic view showing a state in which a corona discharge treatment is performed on a general separation membrane.
2 is a flowchart illustrating a process of performing a separation membrane surface treatment method according to an embodiment of the present invention.
3 is a cross-sectional view of a separation membrane according to an embodiment of the present invention.
4 is a schematic view showing a state where ultraviolet rays are irradiated from a UV lamp according to an embodiment of the present invention.
FIG. 5 is a schematic view showing how ultraviolet rays irradiated from a UV lamp according to an embodiment of the present invention react with oxygen molecules to generate ozone.
FIG. 6 is a graph comparing the impregnation performance in the case of performing the separation membrane surface treatment method according to an embodiment of the present invention and the separation membrane surface treatment method according to the comparative example.
FIG. 7 is a view illustrating a state in which an electrolyte is impregnated into a separation membrane when a separation membrane surface treatment method according to an embodiment of the present invention is performed.
FIG. 8 is a view showing a state in which an electrolytic solution is impregnated into a separation membrane when a separation membrane surface treatment method according to a comparative example is performed.
9 is a graph comparing adhesiveness between the case where the separation membrane surface treatment method according to an embodiment of the present invention is performed and the case where the separation membrane surface treatment method according to the comparative example is performed.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises " and / or " comprising " used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Safety evaluation and safety of electrochemical devices are very important. The most important consideration is that the electrochemical device should not injure the user in case of malfunction. For this purpose, the safety standard strictly regulates the ignition and fuming in the electrochemical device. In the safety characteristics of the electrochemical device, there is a high possibility that the electrochemical device will be overheated to cause thermal runaway or explosion if the separator is penetrated. Particularly, the polyolefin-based porous polymer base usually used as a separator of an electrochemical device exhibits extreme heat shrinkage behavior at a temperature of 100 DEG C or higher owing to the characteristics of the manufacturing process including material properties and elongation, There is a problem causing a short circuit.

In order to solve the safety problem of an electrochemical device, a separation membrane having a porous organic-inorganic coating layer formed by coating a slurry containing a mixture of an excess of inorganic particles and a polymeric binder on at least one surface of a porous polymer substrate having a plurality of pores It was proposed. The inorganic particles contained in the porous organic-inorganic coating layer are excellent in heat resistance, thereby preventing a short circuit between the cathode and the anode even when the electrochemical device is overheated.

However, when the porous coating layer is thinly coated, for example, with a thickness of less than 3 [micro] m on the basis of the cross section of the porous substrate, the adhesion between the separating membrane and the electrode is insufficient. The adhesion between the separator and the electrode is excellent so that the increase in interfacial resistance caused by the separation of the separator and the electrode due to the gas generated by the decomposition product of the electrolyte during the cycle of the electrochemical device can be prevented. In addition, it is possible to prevent the increase of the interface resistance between the separator and the electrode due to the volume expansion of the electrode during the cycle, and to suppress the bending of the electrochemical device in the form of jelly-roll or stack & folding The strength of the electrochemical device can be improved. In this respect, the adhesion between the membrane and the electrode is a very important factor in the electrochemical device.

In order to improve the adhesive strength, conventionally, a slurry was coated on a porous polymer substrate in the process of preparing a separator, and then a corona discharge treatment or a plasma treatment was performed. However, since the membrane is physically damaged, there is a problem that the impregnability of impregnating the electrolyte between the separating membrane and the contact interface of the electrode is lowered.

2 is a flowchart illustrating a process of performing a separation membrane surface treatment method according to an embodiment of the present invention.

In order to solve the above problem, according to an embodiment of the present invention, the ultraviolet ray 101 is irradiated using the UV lamp 10 instead of the corona discharge treatment or the plasma treatment in the separation membrane 1 . Thus, impregnability of the electrolyte solution can be improved without deteriorating the adhesion between the separator 1 and the electrode. Hereinafter, each step of the flowchart of Fig. 2 will be described with reference to Figs. 3 to 5. Fig.

3 is a cross-sectional view of a separation membrane 1 according to an embodiment of the present invention.

3, at least one surface of the porous polymer substrate 11 is coated with a slurry containing a mixture of inorganic particles and a polymer binder to form a porous coating layer 12 (S201).

The porous polymer substrate 11 includes various types of substrates including, but not limited to, a porous polymer substrate based on various polymers, a porous polymer nonwoven substrate, and the like. For example, it is possible to use a polyolefin porous polymer film such as polyethylene or polypropylene, or a nonwoven fabric made of polyethylene terephthalate fiber, which is used as a separator (1) of an electrochemical device, particularly a lithium secondary battery. And can be variously selected according to the purpose. Such a polyolefin porous polymer film can be formed of a polymer in which polyolefin-based polymers such as polyethylene, polypropylene, polybutylene, and polypentene, such as high density polyethylene, linear low density polyethylene, low density polyethylene and ultra high molecular weight polyethylene, have. In addition, the porous polymeric film substrate may be produced by using various polymers such as polyesters in addition to polyolefin. In addition, the porous polymeric film substrate may have a structure in which two or more film layers are laminated, and each film layer is formed of a polymer such as polyolefin, polyester, or the like, It is possible.

The porous polymeric nonwoven substrate may be a polyolefin-based polymer or a polyethyleneterephthalate, a polybutylene terephthalate, a polyester, a polyacetal, a polyamide, or the like, which has a higher heat resistance than the polyolefin- , Polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, and the like. , Polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide, and polyethylene naphthalene, which are used alone or as a mixture of them The nonwoven fabric may be a nonwoven fabric. The structure of the nonwoven fabric may be a spun bond nonwoven fabric or a melt blown nonwoven fabric composed of long fibers. However, the material and the shape of the porous polymer substrate 11 may be variously selected.

The thickness of the porous polymer substrate 11 is not particularly limited, but is preferably 1 to 100 占 퐉, more preferably 5 to 50 占 퐉, and the pore size and porosity present in the porous polymer substrate 11 are also particularly limited But it is preferably 0.01 to 50 μm and 10 to 95%, respectively.

A porous coating layer 12 is formed on at least one side of the porous polymer substrate 11 by coating a slurry containing a mixture of inorganic particles and a polymer binder. The method of coating the slurry is not limited, and various methods can be used, but it is preferable to use a dip coating method. The dip coating is a method in which a substrate is immersed in a tank containing a coating liquid. The thickness of the porous coating layer 12 can be adjusted according to the concentration of the coating liquid and the speed at which the substrate is taken out from the coating liquid tank. A porous coating layer (12) is formed on at least one surface of the substrate (11).

The inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles usable in the present invention are not particularly limited as long as oxidation and / or reduction reaction does not occur 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, the dissociation of the electrolyte salt, for example, the lithium salt in the liquid electrolyte, can be increased, and the ion conductivity of the electrolyte can be improved.

For these reasons, it is preferable that the inorganic particles include high-k inorganic particles having a dielectric constant of 5 or more, preferably 10 or more. Non-limiting examples of the inorganic particles is less than a dielectric constant of 5 is _{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 , Y ₂ O ₃ , Al ₂ O ₃ , boehmite (γ-AlO (OH)), TiO ₂ , SiC or mixtures thereof.

In particular, above a _{BaTiO 3, Pb (Zr, Ti} ) O 3 (PZT), Pb 1 - x La x Zr 1 - y Ti y O 3 (PLZT), Pb (Mg 1/3 Nb 2/3) O 3 Inorganic particles such as PbTiO ₃ (PMN-PT) and hafnia (HfO ₂ ) not only exhibit a high dielectric constant of 100 or more with a dielectric constant of 100, but also generate electric charges when they are stretched or compressed by applying a certain pressure, It is possible to prevent internal short-circuiting of both electrodes due to an external impact, thereby improving the safety of the electrochemical device. Further, when the above-mentioned high-permittivity inorganic particles and inorganic particles having lithium ion transferring ability are mixed, their synergistic effect can be doubled.

As the inorganic particles, inorganic particles having a lithium ion transferring ability, that is, inorganic particles containing a lithium element but having a function of transferring lithium ions without storing lithium may be used. The inorganic particles having lithium ion transferring ability can transfer and move lithium ions due to a kind of defects existing in the particle structure, so that the lithium ion conductivity in the battery is improved and the battery performance can be improved. Nonlimiting examples of inorganic particles having lithium ion transferring ability include lithium phosphate (Li ₃ PO ₄ ), lithium titanium phosphate (Li _x Ti _y (PO ₄ ) ₃ , 0 <x <2, 0 <y <3) phosphate _{(Li x Al y Ti z (} PO 4) 3, 0 <x <2, 0 <y <1, 0 <z <3), 14Li 2 O- 9 Al 2 O 3 -38TiO 2 -39P 2 O 5 (0 <x <4, 0 <y <13), lithium lanthanum titanate (Li _x La _y TiO ₃ , 0 <x <2, 0 <y <3), Li (LiAlTiP) _x O _y series glass _{3 . 25 Ge 0 .25 P 0. 75 S} 4 Mani lithium germanium thiophosphate Titanium _{(Li x Ge y P z S} w, 0 <x <4, 0 <y <1, 0 <z <1, 0 <w such as <5), Li ₃ N lithium nitride _{(Li x N y, 0 <} x <4, 0 <y <2), Li 3 PO 4 SiS 2 family, such as _{-Li 2 S-SiS 2 glass (} Li , such as _{x Si y S z, <x} <3, 0 <y <2, 0 <z <4), LiI-Li 2 SP 2 S 5 P 2 S 5 based glass (Li _x P _y S _z, such as 0 < x <3, 0 <y <3, 0 <z <7), or mixtures thereof.

The average particle diameter of the inorganic particles is not particularly limited, but is preferably in the range of 0.001 to 10 mu m for the formation of the porous coating layer 12 having a uniform thickness and proper porosity. If it is less than 0.001 μm, the dispersibility may be deteriorated. If it exceeds 10 μm, the thickness of the formed porous coating layer 12 may increase, and mechanical properties may be deteriorated. Also, due to an excessively large pore size, The probability of a short circuit is increased.

The polymer binder is preferably a polymer having a glass transition temperature (Tg) of -200 to 200 because it can improve mechanical properties such as flexibility and elasticity of the finally formed coating layer 12 to be.

Further, the polymer binder does not necessarily have ion conductivity, but when the polymer having ion conductivity is used, the performance of the electrochemical device can be further improved. Therefore, it is preferable that the polymer binder has a high permittivity constant. In fact, since the degree of dissociation of the salt in the electrolyte depends on the permittivity constant of the electrolyte solvent, the higher the permittivity constant of the polymeric binder, the better the salt dissociation in the electrolyte. The permittivity constant of the polymeric binder may be in the range of 1.0 to 100 (measurement frequency = 1 kHz), preferably 10 or more.

In addition to the functions described above, the polymeric binder may be characterized by being capable of exhibiting a high degree of swelling of the electrolyte due to gelation upon impregnation with a liquid electrolyte. Accordingly, it is preferable to use a solubility parameter of 15 to 45 MPa ^1/2 of a polymer, and the more preferred solubility parameter of 15 to 25 MPa ^1/2, and 30 to 45 MPa ^1/2 range. Therefore, it is preferable to use hydrophilic polymers having many polar groups, rather than hydrophobic polymers such as polyolefins. If the solubility is more than 15 MPa ^1/2 and less than 45 MPa ^1/2, it is difficult to be impregnated with (swelling) by conventional liquid electrolyte batteries.

Non-limiting examples of such polymeric binders include polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichlorethylene, Polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, and the like. Cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylPolyvinylalcohol, cyanoethylpolyvinylalcohol, Ethyl cellulose (cyanoethylcellulos e), cyanoethylsucrose, pullulan, carboxyl methyl cellulose, and the like.

Further, the polymeric binder may comprise PVDF-HFP. The 'PVDF-HFP polymer binder' refers to a vinylidene fluoride copolymer comprising a constituent unit of vinylidene fluoride (VDF) and a constituent unit of hexafluoropropylene (HFP). However, the polymeric binder is not limited thereto and may include various materials.

The weight ratio of the inorganic particles to the polymeric binder is preferably in the range of, for example, 50:50 to 99: 1, more preferably 70:30 to 95: 5. When the content ratio of the inorganic particles to the polymeric binder is less than 50:50, the content of the polymer is increased and the pore size and porosity of the formed coating layer 12 can be reduced. If the content of the inorganic particles exceeds 99 parts by weight, the filler content of the formed coating layer 12 may be weakened because the content of the polymeric binder is small.

As the solvent of the polymeric binder, it is preferable that the solubility index is similar to that of the polymer binder to be used, and the boiling point is low. This is to facilitate uniform mixing and subsequent solvent removal. Non-limiting examples of usable solvents include acetone, tetrahydrofuran, methylene chloride, chloroform, dimethylformamide, N-methyl-2-pyrrolidone ( N-methyl-2-pyrrolidone, NMP), cyclohexane, water or a mixture thereof.

The slurry in which the inorganic particles are dispersed and the polymeric binder is dissolved in the solvent can be prepared by dissolving the polymeric binder in a solvent and then adding and dispersing the inorganic particles. The inorganic particles may be added in a state of being crushed to an appropriate size, but it is preferable to add inorganic particles to the solution of the polymeric binder and then disperse the inorganic particles by crushing using a ball mill method or the like.

4 is a schematic view showing a state in which ultraviolet light 101 is irradiated from a UV lamp 10 according to an embodiment of the present invention.

According to an embodiment of the present invention, as shown in FIG. 4, a conventional corona discharge treatment or a plasma treatment is not performed on the separation membrane 1, and instead, the ultraviolet ray 101 is irradiated using the UV lamp 10 (S202). Therefore, impregnation of the electrolytic solution can be improved by using only the chemical treatment method without physically damaging the separation membrane 1.

The UV lamp 10 is a lamp that emits ultraviolet rays 101 (UV, Ultra-Violet rays) to the outside. The ultraviolet ray 101 is an electromagnetic wave having a shorter wavelength than the visible ray, and has a wavelength of approximately 10 to 400 nm. The wavelength is so short that it can not be seen by the human eye, it has high chemical and high energy and is easily used for sterilization and bleaching.

According to one embodiment of the present invention, ultraviolet ray 101 irradiated from UV lamp 10 reacts with oxygen molecules 13 in air to generate ozone 15 (S203).

5 is a schematic view showing a state in which ultraviolet rays 101 irradiated from a UV lamp 10 according to an embodiment of the present invention react with oxygen molecules 13 to generate ozone 15.

Specifically, as shown in FIG. 5, the ultraviolet ray 101 breaks the binding of the oxygen molecules 13 present in the air. The oxygen molecule (13) is bonded to a covalent bond in which two oxygen atoms (14) share electrons. The covalent bond is a very strong molecular bond, and the oxygen molecule 13 bonded with such a covalent bond has a low energy level. However, the ultraviolet ray 101 breaks the covalent bond of the oxygen molecule 13 by using high energy, and two oxygen atoms 14 are generated. The oxygen atom (14) is in an unstable state because of its very high energy. Therefore, the ozone 15 does not exist for a long period of time alone, and the ozone 15 is generated by bonding with other oxygen molecules 13 in the periphery.

The ozone 15 is a light blue gas and has a strong oxidizing power, thereby oxidizing surrounding substances. Therefore, silver can be oxidized to silver peroxide, lead sulfide to lead sulfate, and sulfur to oxidation sulfur. According to an embodiment of the present invention, when the ozone 15 is generated by irradiating the ultraviolet ray 101 to the outside of the UV lamp 10, the ozone 15 oxidizes the porous coating layer 12 formed on the separation membrane 1 (S204). When the porous coating layer 12 is oxidized, in particular, when it contains PVDF-HFP, a hydrophilic group (for example, -CO-, -COH, -COOH, etc.) containing oxygen atom 14 is generated on the surface. Since such a hydrophilic group has strong adhesiveness, the impregnability of the electrolytic solution is improved rather than the lowering of the adhesive force as compared with the case of performing the corona discharge treatment.

On the other hand, a concentration measuring device for measuring the concentration of the oxygen 13 or ozone 15 in the air can be further provided. The concentration meter preferably measures at least one of the oxygen 13 and the ozone 15 and is capable of measuring both the oxygen 13 and the ozone 15. When the concentration measuring device measures the concentration of oxygen 13, it is possible to further provide an oxygen generator 13 capable of supplying the deficient oxygen 13 when the oxygen 13 in the air is insufficient. On the other hand, when the concentration meter measures the concentration of the ozone 15, when the ozone 15 in the air is insufficient, the porous coating layer 12 on the surface of the separation membrane 1 can not be sufficiently oxidized, It is possible to increase the amount of the ultraviolet ray 101 emitted from the light source 101. [ On the contrary, when the ozone 15 in the air is excessive, the amount of the ultraviolet ray 101 emitted from the UV lamp 10 can be reduced. At this time, according to an embodiment of the present invention, a user may determine the concentration of ozone 15 through a concentration meter and directly adjust the amount of ultraviolet ray 101 emitted by adjusting the UV lamp 10. According to another embodiment of the present invention, a separate control unit (not shown) is provided. When the concentration of the ozone 15 is different from the preset concentration of the ozone 15, 10, the ultraviolet ray 101 emission amount adjustment signal may be applied. Thereby, the emission amount of the ultraviolet ray 101 emitted from the UV lamp 10 can be automatically adjusted. The controller may be a central processing unit (CPU), a microcontroller unit (MCU), or a digital signal processor (DSP), but the present invention is not limited thereto.

Meanwhile, if the concentration of the ozone 15 is sufficient but the oxidizing power against the porous coating layer 12 is insufficient, an air blower may be further provided to collect the ozone 15 around the porous coating layer 12 and blow it to the porous coating layer 12 .

The separator 1 manufactured according to the above method is interposed between the cathode and the anode and laminated to produce an electrochemical device. The electrochemical device includes all devices that perform an electrochemical reaction. Examples of the electrochemical device include a capacitor such as a primary cell, a secondary cell, a fuel cell, a solar cell, or a supercapacitor. Particularly, 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 above secondary batteries is preferable.

The cathode and the anode both to be applied together with the separator 1 of the present invention are not particularly limited and the electrode active material may be bound to the electrode current collector according to a conventional method known in the art. Examples of the cathode active material include, but are not limited to, lithium manganese oxide, lithium cobalt oxide, lithium nickel oxide, lithium iron oxide, or a combination thereof It is preferable to use a lithium composite oxide. As a non-limiting example of the anode active material, a conventional anode active material that can be used for an anode of an electrochemical device can be used. In particular, lithium metal or a lithium alloy, carbon, petroleum coke, activated carbon, Lithium-adsorbing materials such as graphite or other carbon-based materials and the like are preferable. Non-limiting examples of the cathode current collector include aluminum, nickel, or a combination thereof, and examples of the anode current collector include copper, gold, nickel, or a copper alloy or a combination thereof Foil to be manufactured, and the like.

The electrolytic solution which can be used in the electrochemical device of the present invention is a salt having a structure such as A ⁺ B ^- , wherein A ⁺ includes an alkali metal cation such as Li ^+, Na ^+, K ^{+ -} it 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 (DMP), dimethylsulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), gamma butyrolactone -Butyrolactone), or a mixture thereof, but the present invention is not limited thereto.

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

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples. However, the embodiments according to the present invention can be modified into various other 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 enable those skilled in the art to more fully understand the present invention.

FIG. 6 is a graph comparing the impregnation performance of the membrane surface treatment method according to an embodiment of the present invention and the membrane surface treatment method according to the comparative example. FIG. FIG. 8 is a view showing a state in which the electrolytic solution is immersed in the separator 1 when the separator surface treatment method according to the comparative example is carried out. FIG. Fig.

According to the separation membrane surface treatment method according to an embodiment of the present invention, the Jelight UV / Ozone cleaner was used as the UV lamp 10, and the ultraviolet ray 101 was irradiated to the outside with a light amount of 25 mW / cm ² . The distance between the UV lamp 10 and the separator 1 was 5 mm, the width of the separator 1 was 10 cm x 5 cm, and the total thickness of the separator 1 was 12 μm. The porous coating layer 12 of the separation membrane 1 contained PVDF-HFP (HFP 5 to 20 wt%), and the porous coating layer 12 had a thickness of 3 to 5 μm.

On the other hand, according to the separation membrane surface treatment method according to the comparative example, a corona electrode was used instead of the UV lamp 10, and the same procedure as in the above example was performed. At this time, the electric power used for the corona electrode was 200 W.

A plurality of first separation membrane samples having been subjected to the separation membrane surface treatment method according to an embodiment of the present invention are provided and a plurality of second separation membrane samples having the separation membrane surface treatment method according to the comparative example are also provided, Impregnated. Then, the first and second separation membrane samples were taken out one by one at the same time, and the area impregnated was measured. As a result, the same result as the graph shown in Fig. 6 was derived.

The graph shown in Fig. 6 shows the area (mm ² ) in which the X-axis is time (min) and the Y-axis is impregnated in the electrolyte solution. The slope represents the area impregnated into the electrolyte per unit time, and the faster the slope is, the faster the rate of impregnation into the electrolyte is. As shown in FIG. 6, when the separation membrane surface treatment method according to an embodiment of the present invention is performed, the slope thereof is approximately 2.54, but when the separation membrane surface treatment method according to the comparative example is performed, the slope thereof is approximately 1.95. That is, when the separation membrane surface treatment method according to an embodiment of the present invention is performed, the rate at which the electrolyte is impregnated is about 30% faster than that of the separation membrane surface treatment method according to the comparative example.

7 and 8, when the separation membrane surface treatment method according to an embodiment of the present invention is performed, the electrolyte is impregnated to a depth of at least 25 mm, but when the separation membrane surface treatment method according to the comparative example is performed , The electrolyte was impregnated to a depth of at least 21 mm. That is, when the separation membrane surface treatment method according to an embodiment of the present invention is performed, the depth of the electrolyte impregnation is about 20% deeper than that of the separation membrane surface treatment method according to the comparative example.

9 is a graph comparing adhesiveness between the case where the separation membrane surface treatment method according to an embodiment of the present invention is performed and the case where the separation membrane surface treatment method according to the comparative example is performed.

The adhesiveness of the first membrane sample and the second membrane sample was measured as well as the impregnation property. The first and second separation membrane samples were adhered to electrodes of the same condition, respectively, and the external force applied to the electrodes was measured to measure the adhesion.

As shown in FIG. 9, the first separation membrane sample had an adhesive force of about 20 to 25 gf / 15 mm, while the second separation membrane sample had an adhesive force of 8 to 15 gf / 15 mm. That is, when the separation membrane surface treatment method according to one embodiment of the present invention is performed, it can be seen that the adhesion strength is increased by at least 30% as compared with the case of performing the separation membrane surface treatment method according to the comparative example.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing description, and various embodiments derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

1, 2: separator 10: UV lamp
11: Porous polymer base material 12: Porous coating layer
13: oxygen molecule 14: oxygen atom
15: ozone 20: conventional corona electrode
21: conventional ground electrode 22: particle
101: ultraviolet ray

Claims (15)

Forming a porous coating layer on the porous polymer substrate to prepare a separation membrane;
Irradiating ultraviolet rays to the space in which the separation membrane is disposed;
Reacting the ultraviolet ray with oxygen present in the air to generate ozone;
And the ozone oxidizing the surface of the separation membrane. The method according to claim 1,
In the step of generating ozone,
Wherein the concentration meter further measures the concentration of oxygen or ozone present in the air. 3. The method of claim 2,
Wherein the oxygen generator further supplies oxygen when the oxygen concentration is insufficient. 3. The method of claim 2,
Wherein the concentration meter measures ozone, and when the concentration of the measured ozone is different from the predetermined ozone concentration, the control section applies an ultraviolet ray emission amount adjustment signal to the UV lamp. The method according to claim 1,
The porous polymer base material may be,
A porous polymeric film base, or a porous polymeric nonwoven base. 6. The method of claim 5,
In the porous polymer film substrate,
Based on a polyolefin-based porous polymer film. The method according to claim 6,
In the polyolefin-based porous polymer film base,
Wherein one or more selected from the group consisting of polyethylene, polypropylene, polybutylene and polypentene are selectively formed. 6. The method of claim 5,
The porous polymeric nonwoven fabric substrate may include a non-
Polyolefin-based polymers, polyethyleneterephthalate, polybutylene terephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, Polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide (polyetheretherketone), polyetheretherketone (polyetheretherketone), polyetheretherketone Wherein at least one selected from the group consisting of polyphenylene oxide, cyclic olefin copolymer, polyphenylenesulfide and polyethylene naphthalene is selected and formed. The method according to claim 1,
The thickness of the porous polymer base material is,
5 to 50 [mu] m. The method according to claim 1,
The pore size of the porous polymer base material is,
0.01 to 50 탆. The method according to claim 1,
The porosity of the porous polymer base material is,
10 to 95%. The method according to claim 1,
Wherein the porous coating layer
Wherein a slurry comprising a mixture of inorganic particles and a polymeric binder is formed by coating with a dip coating method. 13. The method of claim 12,
The average particle diameter of the inorganic particles is,
0.001 to 10 [micro] m. 13. The method of claim 12,
The inorganic particles may include,
The inorganic particles having a dielectric constant of 5 or more, and the inorganic particles having a lithium ion transporting ability. 13. The method of claim 12,
In the polymer binder,
RTI ID = 0.0 &gt; PVDF-HFP. &Lt; / RTI &gt;

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