WO2013062251A1 - Multilayered separator for lithium secondary battery using functional polymer, and preparation method thereof - Google Patents

Multilayered separator for lithium secondary battery using functional polymer, and preparation method thereof Download PDF

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Publication number
WO2013062251A1
WO2013062251A1 PCT/KR2012/008206 KR2012008206W WO2013062251A1 WO 2013062251 A1 WO2013062251 A1 WO 2013062251A1 KR 2012008206 W KR2012008206 W KR 2012008206W WO 2013062251 A1 WO2013062251 A1 WO 2013062251A1
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Prior art keywords
layer
separator
secondary battery
formula
polyolefin
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PCT/KR2012/008206
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French (fr)
Korean (ko)
Inventor
문승현
이주영
신성희
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광주과학기술원
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Priority claimed from KR1020110113525A external-priority patent/KR101268281B1/en
Application filed by 광주과학기술원 filed Critical 광주과학기술원
Publication of WO2013062251A1 publication Critical patent/WO2013062251A1/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
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457—Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • 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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • 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
    • 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 multilayer structure separator for a lithium secondary battery using a functional polymer, and more particularly, to a separator having a multilayer structure made of a functional polymer having excellent mechanical strength and excellent thermal stability and a polyolefin-based polymer, and a method of manufacturing the same. will be.
  • Lithium secondary batteries are energy storage devices capable of repeating charge and discharge through reversible interconversion of chemical and electrical energy.
  • Separator one of the core parts of the lithium secondary battery, prevents contact between the cathode and the anode of the battery and serves to transfer lithium ions from the anode to the cathode or from the cathode to the anode in the electrolyte.
  • the separator plays a simple role of separating the positive electrode and the negative electrode, but if the separator is torn or damaged, a short circuit between the positive electrode and the negative electrode may cause a fire explosion due to oxidation of lithium. Since there have been several explosion cases, the role of the membrane is very important in terms of stability. In particular, in the case of high-capacity batteries for automobiles that require high performance and high stability, the development of a separator having excellent characteristics is urgently needed.
  • Korean Patent Publication No. 10-2011-0032227 modified the surface using ceramic particles, which showed an effective ability to increase the strength of the separator, but did not completely improve the thermal stability.
  • Korean Patent Publication No. 10-2011-0032227 modified the surface using ceramic particles, which showed an effective ability to increase the strength of the separator, but did not completely improve the thermal stability.
  • an additional material needs to be added for wettability of the separator.
  • the first problem to be solved by the present invention is a lithium secondary battery separator, while maintaining excellent mechanical strength and at the same time excellent thermal stability shut-down (shut-down) and melt-down (melt-down) effect It is to provide a multilayer structure separator for a lithium secondary battery using the enhanced functional polymer.
  • the second problem to be solved by the present invention is to provide a method of manufacturing a multilayer structure separator for a lithium secondary battery using the functional polymer.
  • the present invention to achieve the first object,
  • the separator is a first layer; Second layer; And a third layer existing between the first layer and the second layer.
  • the first layer and the second layer is a compound layer represented by the following [Formula 1]; Or a polyolefin-based polymer layer coated with a compound represented by the following [Formula 1], and the third layer is a polyolefin-based polymer layer;
  • an adhesive material is applied between the first layer and the third layer and between the second layer and the third layer, wherein the adhesive material is vinyl It is an aqueous polymer solution in which ethylene acetate is diluted in water,
  • the polyolefin-based polymer provides a separator for a lithium secondary battery, characterized in that polyethylene or polypropylene.
  • R is 0 ⁇ r ⁇ 1, and n is an integer between 1 and 5000.
  • the present invention is a separator for a lithium secondary battery composed of a polyolefin-based polymer and a compound represented by the following [Formula 1],
  • the separator is a first layer; Second layer; And a third layer existing between the first layer and the second layer.
  • the first layer, the second layer and the third layer are each independently a polyolefin-based polymer layer, the outer surface of the separator is coated with a compound represented by the following [Formula 1],
  • the polyolefin-based polymer provides a separator for a lithium secondary battery, characterized in that polyethylene or polypropylene,
  • the first layer and the second layer may be a polypropylene polymer layer
  • the third layer may be a polyethylene polymer layer, the surface of the first layer that does not adhere to the third layer, and the second layer that does not adhere to the third layer.
  • the surface of may be coated with a compound represented by the following [Formula 1]. That is, the separator is laminated with a polyolefin-based polymer layer, and has a three-layer structure, and the entire outer surface of the separator may be coated with the compound represented by [Formula 1].
  • R is 0 ⁇ r ⁇ 1, and n is an integer between 1 and 5000.
  • the particles of the applied adhesive material may be 1-500 ⁇ m.
  • the present invention to achieve the second object,
  • the solvent is any one selected from N-methyl-2-pyrrolidone, chloroform, tetrahydrofuran, benzene, toluene and xylene,
  • the polyolefin-based polymer is polyethylene or polypropylene
  • the adhesive material provides a method of manufacturing a separator for a secondary battery, characterized in that the aqueous polymer solution diluted with vinyl ethylene acetate in water.
  • R is 0 ⁇ r ⁇ 1, and n is an integer between 1 and 5000.
  • the step (a) may further include any one of non-solvents selected from butanol and propanol in order to prevent the fast evaporation rate of the solvent, and the solvent: cost
  • the volume ratio of the hawk may be 1.5-4: 1.
  • the particle size of the adhesive material applied in the step (c) may be 1-500 ⁇ m to maintain the pore of the porous separator according to the invention.
  • the separator laminated in three layers in step (c) may be prepared by pressing by a hot-pressing method, the temperature 120-130 °C and 100-300 kg ⁇ f / cm 2 By pressing for 1-5 seconds at a pressure of can be prepared a separator laminated in three layers.
  • the present invention (d) dissolving a compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution;
  • the polyolefin-based polymer is polyethylene or polypropylene
  • the adhesive material provides a method of manufacturing a separator for a secondary battery, characterized in that the aqueous polymer solution diluted with vinyl ethylene acetate in water.
  • R is 0 ⁇ r ⁇ 1, and n is an integer between 1 and 5000.
  • the solvent in the step (d) may be a volatile chloroform solvent in that the solvent for preparing a polymer solution to be coated on a polyolefin-based polymer film.
  • a dip-coating method in order to coat the polymer solution on a polyolefin-based polymer film in a very thin layer, a dip-coating method may be used, and the dip-coating of The speed can be 8-9 mm / minute.
  • the particle size of the adhesive material applied in the step (f) may be 1-500 ⁇ m to maintain the pore of the porous separator according to the invention.
  • the separator laminated in three layers in the step (f) may be prepared by pressing by hot-pressing method, 120-130 °C temperature and 100-300 kg ⁇ f / cm 2 By pressing for 1-5 seconds at a pressure of can be prepared a separator laminated in three layers.
  • the present invention (g) dissolving the compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution;
  • the polyolefin-based polymer separator laminated in three layers comprises a first layer; Second layer; And a third layer existing between the first layer and the second layer.
  • the first layer and the second layer are positioned above and below the third layer, and the adhesive material is applied to each interface and then compressed.
  • the polyolefin-based polymer provides a method for manufacturing a secondary battery separator, characterized in that the polyethylene or polypropylene, wherein the first layer and the second layer is a polypropylene polymer layer, the third layer may be a polyethylene polymer layer.
  • R is 0 ⁇ r ⁇ 1, and n is an integer between 1 and 5000.
  • a polymer solution containing the compound represented by the above [Formula 1] After coating on one surface of both surfaces of the first layer and the second layer to prepare a first layer and a second layer film, each of which is coated with a compound represented by [Formula 1], one surface of both surfaces, A surface not coated with the compound represented by 1] may be adhered to the third layer, respectively, to prepare a separator laminated in a three-layer structure in which the entire exterior of the separator is coated with the compound represented by [Formula 1].
  • the separator is laminated with a polyolefin-based polymer layer is composed of a three-layer structure, and the entire outer surface of the separator is coated with a compound represented by the above [Formula 1] and the characteristics of the separator is included in the scope of the present invention Will be done.
  • the multilayered separator for a lithium secondary battery using the functional polymer according to the present invention exhibits low thermal shrinkage and improved flame retardancy, and thus has excellent thermal stability, and at the same time, shows high porosity and excellent mechanical properties similar to those of commercially available separators. It can be directly commercialized as a battery separator.
  • FIGS. 1A to 1C are conceptual views illustrating separators for a lithium secondary battery stacked in a three-layer structure according to an embodiment of the present invention.
  • 2A and 2B are SEM images showing the surface and the cross section of the separator (BPPO-PE-BPPO) prepared according to Example 1 of the present invention, respectively.
  • 2C and 2D are SEM images showing the surface and the cross-section of the separator (PP-PE-BPPO coated PP coated with BPPO) prepared according to Example 2 of the present invention, respectively.
  • 2E and 2F are SEM images showing a surface and a cross section of a separator of a BPPO-coated three-layer laminated (PP / PE / PP) structure prepared according to Example 3 of the present invention, respectively.
  • thermo shrinkage thermal shrinkage
  • thermo shrinkage thermal shrinkage
  • FIG. 6 is a graph showing a comparison of potentials according to unit capacity as a result of cell testing using the separator according to the present invention.
  • FIG. 7A and 7B are cell test results using the separator according to the present invention.
  • FIG. 7A is a graph showing a comparison of relative capacity ratios according to the number of cycles. to be.
  • the present invention is a compound (BPPO (brominated poly (phenylen oxide)) and polyolefin-based compound represented by the following [Formula 1] as a functional polymer in order to solve the thermal stability and affinity for a liquid electrolyte in the separator of a conventional lithium secondary battery It is made of a polymer, and provides a separator for a lithium secondary battery formed in a multilayer structure.
  • BPPO brominated poly (phenylen oxide)
  • [Formula 1] as a functional polymer in order to solve the thermal stability and affinity for a liquid electrolyte in the separator of a conventional lithium secondary battery It is made of a polymer, and provides a separator for a lithium secondary battery formed in a multilayer structure.
  • r is 0 ⁇ r ⁇ 1
  • n is an integer between 1 and 5000.
  • the brominated poly (phenylen oxide) (BPPO) compound represented by the above [Formula 1] has a molecular structure similar to that of a liquid electrolyte additive and has good wettability, and the bromine functional group of the BPPO structure has a function of inhibiting radical reaction. It reduces the ignition of the liquid electrolyte present in the voids, and eventually serves to reduce the explosion risk of the lithium rechargeable battery.
  • the separator according to the present invention is combined with a polyolefin-based polymer to enhance mechanical strength, shut down effect (micropore closure function when the battery is overheated) and melt down effect (maintain film form even at an additional temperature increase), which are essential elements of the separator. It is the separator of the 3-layer structure used.
  • the multilayer membrane according to the present invention is a separator for a lithium secondary battery comprising a polyolefin-based polymer and the compound represented by the above [Formula 1], wherein the separator is a first layer, a second layer, and the first and second layers. It consists of a third layer present between, wherein the first layer and the second layer is a polyolefin-based polymer layer coated with a compound layer represented by the above [Formula 1] or a compound represented by the [Formula 1],
  • the third layer is a polyolefin-based polymer layer, and an adhesive material between the first layer and the third layer and between the second layer and the third layer before attaching and compressing the first layer, the second layer, and the third layer.
  • the adhesive material is an aqueous polymer solution obtained by diluting vinyl ethylene acetate in water, and the polyolefin-based polymer is polyethylene or polypropylene.
  • the multi-layer separator according to the present invention is a separator for a lithium secondary battery consisting of a polyolefin-based polymer and the compound represented by the above [Formula 1], the separator is a first layer, a second layer and the first layer and the first It consists of a third layer existing between the two layers, wherein the first layer, the second layer and the third layer are each independently a polyolefin-based polymer layer, the outer surface of the separator is represented by [Formula 1] It is characterized by being coated with a compound.
  • the first layer and the second layer may be a polypropylene polymer layer
  • the third layer may be a polyethylene polymer layer, the surface of the first layer that does not adhere to the third layer, and the second layer that does not adhere to the third layer.
  • the surface of may be coated with a compound represented by the above [Formula 1]. That is, the separator is laminated with a polyolefin-based polymer layer, and has a three-layer structure, and the entire outer surface of the separator may be coated with the compound represented by [Formula 1].
  • the three-layer separator is a BPPO / PE (polyethylene) / BPPO-structured three-layer separator and PP (polypropylene) coated with BPPO.
  • BPPO / PE polyethylene
  • PP polypropylene
  • / PE / BPPO coated three-layer structure membrane of PP structure or the outer surface of the membrane may be a three-layer structure membrane (BPPO-PP / PE / PP-BPPO) coated with BPPO and laminated with a polyolefin-based polymer layer.
  • the adhesive material may be a vinyl ethylene acetate (VEA) -based hot melt adhesive, and as a specific adhesive, Air Product Co., Ltd. Air flex EP 645, EP 705, EP 707K, 920 and the like.
  • the adhesive material may be applied by ultra air spraying, screen printing or hydraulic spraying, and the particle size of the applied adhesive material is preferably 1-500 ⁇ m.
  • the present invention provides a method of manufacturing a separator for a lithium secondary battery formed in the multilayer structure, and a process of preparing a film by casting a functional polymer BPPO or coating by a dip-coating method, after the olefin-based separator and It is made of a process of laminating and bonding in three layers by bonding, the detailed process of the manufacturing method is as follows.
  • the solvent for preparing the polymer solution in (1) may be any one selected from N-methyl-2-pyrrolidone, chloroform, tetrahydrofuran, benzene, toluene and xylene, and also the fast Butanol or propanol may be added as a non-solvent that is further stirred to counteract the rate of evaporation and the volume ratio of solvent to nonsolvent is preferably 4: 1 or 3: 2.
  • the solvent used in the above (1) is preferably volatile volatile.
  • a method of manufacturing a three-layer structure membrane in which the outer surface of the separator is coated with BPPO and laminated with a polyolefin-based polymer layer, (4) dissolving the compound represented by the following [Formula 1] in a solvent and stirring Preparing a polymer solution;
  • the polyolefin-based polymer separator laminated in three layers comprises a first layer; Second layer; And a third layer existing between the first layer and the second layer.
  • the first layer and the second layer are positioned above and below the third layer, and the adhesive material is applied to each interface and then compressed.
  • the solvent used in (4) is preferably volatile volatile.
  • a dip-coating method is used when the polymer solution is coated on a polyolefin-based polymer film, and the dipping and withdrawing speed is 8-9 mm / min during the dip-coating. It is desirable to maintain the pores of the original membrane by minimizing the
  • the polymer solution containing the compound represented by the above [Formula 1] After coating on one of both surfaces of the first layer and the second layer to prepare a first layer and a second layer film each of which is coated with a compound represented by [Formula 1], one surface of both surfaces, [Formula 1]
  • Each of the surfaces not coated with the compound represented by 3 may be adhered to the third layer to prepare a separator laminated in a three-layer structure in which the entire exterior of the separator is coated with the compound represented by [Formula 1].
  • the separator is laminated with a polyolefin-based polymer layer is composed of a three-layer structure, and the entire outer surface of the separator is coated with a compound represented by the above [Formula 1] and the characteristics of the separator is included in the scope of the present invention Will be done.
  • Preparation of a three-layer separator according to the present invention comprises the steps of preparing a porous separator using a functional polymer BPPO (brominated poly (phenylen oxide)), and the olefin-based separator of polyethylene (Poly ethylene, PE) It consists of a three-layer separator manufacturing step of laminating the BPPO porous separator on both sides.
  • BPPO brominated poly (phenylen oxide)
  • PE polyethylene
  • BPPO single layer separator
  • the adhesive was diluted 1 / 2000-fold of Air flex EP 645 and 0.5 ml of adhesive was applied on the base area of 4 x 4 cm 2 of the BPPO membrane as the first layer by the ultra air spray method.
  • the adhesive is applied to the upper surface of the PE, which is the third layer, the first layer is laminated, and then turned over.
  • the adhesive is also applied to the back of the third layer and the second layer is laminated. It was laminated in order.
  • the three-layer laminate structure of BPPO / PE / BPPO was instantaneously bonded within 5 seconds using a hot pressing machine at 120-130 ° C. and 100-300 kg ⁇ f / cm 2 .
  • Preparation of a three-layer separator according to the present invention is to prepare a porous membrane of BPPO-coated PP by dip-coating the functional polymer BPPO on the surface of polypropylene (Poly propylene, PP), an olefin-based separator And, it is composed of a three-layer separator manufacturing step of laminating a porous separator of PP coated with BPPO on both sides of the polyethylene (Poly ethylene, PE) of the olefin-based separator.
  • the monolayer separator prepared in Example 2- (2) (porous separator of PP coated with BPPO) is composed of an outer layer as a first layer and a second layer, and the first layer and the first layer using PE as a third layer. As the inner layer existing between the two layers, it was bonded in a three-layer laminate structure of BPPO coated PP / PE / BPPO coated PP.
  • the adhesive was diluted with air flex EP 645 by 1/2000 times and 0.5 ml of adhesive was applied onto the reference area of 4 x 4 cm 2 of the porous membrane of BPPO-coated PP as the first layer by ultra air spray method. Thereafter, the third layer of PE was put on, and then bonded using hot pressing at 120-130. In addition, the separator of the third layer and the second layer was also bonded in the same manner to prepare a three-layer separator.
  • a membrane having a thickness of 25 was used as a single layer of a commercially available olefin-based polypropylene as a polymer sheet.
  • the separator prepared in accordance with the present invention is porous and thus as a separator. It is shown that the movement of lithium ions, as shown in Figure 2b (cross section of the separator prepared according to Example 1) and Figure 2d (cross section of the separator prepared according to Example 2) below, the present invention It can be seen that the separator prepared according to the lamination is made of a three-layer structure.
  • the layer is laminated in a three-layer structure, and the pores are connected. It can be confirmed.
  • Example 1 to Example 3 which is a separator having a three-layer structure manufactured according to the present invention, in order to confirm the porosity retention of the separator prepared by laminating in a three-layer structure according to the present invention, compared with a commercialized comparative example Air permeability and porosity was confirmed.
  • Air permeability was calculated by passing a constant air pressure through a prepared membrane of 13 mm in diameter by measuring the air pressure passed by a bubble meter to calculate the Gurley value.
  • Table 1 shows the air permeability results of Examples 1 to 3 and Comparative Examples.
  • Example 2 when the value of the Example and the comparative example does not show a large difference, it can be seen that the effect of the adhesive when laminating in a three-layer structure, Examples 2 to 3
  • the porosity of is somewhat lower than that of the comparative example due to the decrease in pore size due to the coating of BPPO, but the porosity is well maintained at about the same level.
  • the separator prepared according to the present invention shows that the possibility of practical use is sufficient to replace the commercially available separator.
  • thermal shrinkage experiments and flammability experiments were performed using the above examples and comparative examples.
  • Comparative Example 2 shows a thermal shrinkage of 71.1%, Example 1 is 4.9%, Example 3 is 50.1% so that the sample of the Comparative Example is more thermally compared to Examples 1 and 3 It can be seen that the shrinkage is large.
  • Example 1 since the lamination of the three-layer separator is very well, the BPPO separators on both sides are firmly supported even if the PE between the BPPO separators is contracted, thereby showing very improved thermal stability. This shows that the thermal shrinkage of the separator is greatly improved due to the thermal stability of the functional polymer used in the present invention. That is, it can be seen that the thermal stability at a high temperature is superior to that of the separator according to the present invention commercially available.
  • Flammability test was performed by wetting the separator with electrolyte, removing only the electrolyte on the surface, and lighting it. It measured the ignition time from the start of combustion until it completely turned off and confirmed the remaining state of the separator after complete combustion. The combustion process over time is shown in FIG. 5.
  • Example 1 stopped combustion in 4 seconds
  • Example 2 in 9 seconds
  • part of the separator remained after combustion of the electrolyte in the separator.
  • Comparative Example 2 the separation membrane was separated and melted for 2 seconds after the start of combustion, and spark generation due to oxidation of lithium was also confirmed during the combustion process.
  • the membrane was completely burned out.
  • This stably combusts the electrolyte containing the lithium salt in the separator according to the flame retardant properties of the functional polymer used in the present invention, and leaves a residue of the separator even after combustion, thereby preventing contact short-circuit during explosion of the lithium ion battery for a long time, thereby ensuring thermal stability. This is very good.
  • Example 6 shows the test results of Examples 1 and 3 and Comparative Example 2 as potentials according to the capacity, and shows a charge / discharge graph of the 10th cycle.
  • the discharge capacities of Examples 1, 3 and Comparative Example 2 were represented by 126.6 mAh / g, 124.2 mAh / g, and 124.4 mAh / g, respectively. It was found that the capacity was higher, and Example 3 showed almost the same capacity as the cell test of a commercially available separator.
  • FIGS. 7A and 7B are graphs showing relative capacity ratios and coulombic efficiencies according to cycle times of the lithium secondary batteries of Examples 1 and 3 and the lithium secondary batteries of Comparative Example 2, as shown in FIGS. 7A and 7B. It can be seen that the lithium secondary battery to which the separator of Example 1 according to the present invention is applied has a high relative capacity rate and coulombic efficiency as the number of charge and discharge cycles increases. In addition, it can be seen that the lithium secondary battery to which the separator of Example 3 according to the present invention is applied has a relative capacity similar to that of the secondary battery of Comparative Example 2 as the number of charge and discharge cycles increases, and the coulombic efficiency is high.
  • the performance of the lithium secondary battery to which the separator according to the present invention is applied is more improved or comparable to that of the commercially available separator, and thus, it can be seen that the lithium secondary battery can be sufficiently used as a replacement of the separator of the comparative example.

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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

The present invention relates to a multilayered separator for a lithium secondary battery using a functional polymer, comprising a polyolefin-based polymer and a compound represented by chemical formula 1. The multilayered separator for a lithium secondary battery using a functional polymer according to the present invention has very excellent thermal stability due to low heat shrinkage and improved flame retardancy, and at the same time can be commercialized as a separator for a lithium secondary battery due to having the same level of high porosity and excellent mechanical properties as existing commercialized separators.

Description

기능성 고분자를 이용한 리튬 이차전지용 다층구조 분리막 및 그 제조방법Multi-layered separator for lithium secondary battery using functional polymer and manufacturing method
본 발명은 기능성 고분자를 이용한 리튬 이차전지용 다층구조 분리막에 관한 것으로서, 더욱 상세하게는 기계적 강도가 우수하고, 열적 안정성이 우수한 기능성 고분자와 폴리올레핀 계열의 고분자로 이루어진 다층 구조의 분리막 및 그 제조방법에 관한 것이다.The present invention relates to a multilayer structure separator for a lithium secondary battery using a functional polymer, and more particularly, to a separator having a multilayer structure made of a functional polymer having excellent mechanical strength and excellent thermal stability and a polyolefin-based polymer, and a method of manufacturing the same. will be.
리튬 이차전지는 화학적 에너지와 전기 에너지의 가역적 상호변환을 통하여 충전과 방전을 반복할 수 있는 에너지 저장 장치이다. 리튬 이차전지의 핵심 부품 중 하나인 분리막은 전지의 양극과 음극의 접촉을 방지하고 전해질 내에서 리튬 이온을 양극에서 음극으로 또는 음극에서 양극으로 전달하는 역할을 하고 있다. 분리막은 양극과 음극을 분리하는 간단한 역할을 하고 있지만, 분리막이 찢어지거나 상처가 나서 양극과 음극의 단락이 생길 경우 리튬의 산화로 인한 화재 폭발이 일어날 수 있다. 현재에도 여러 폭발 사례가 나왔기 때문에 분리막의 역할은 안정성의 측면에서 매우 중요하다. 특히, 고성능과 고안정성이 요구되는 자동차용 고용량 전지의 경우 우수한 특성을 지니는 분리막의 개발이 절실히 필요한 실정이다.Lithium secondary batteries are energy storage devices capable of repeating charge and discharge through reversible interconversion of chemical and electrical energy. Separator, one of the core parts of the lithium secondary battery, prevents contact between the cathode and the anode of the battery and serves to transfer lithium ions from the anode to the cathode or from the cathode to the anode in the electrolyte. The separator plays a simple role of separating the positive electrode and the negative electrode, but if the separator is torn or damaged, a short circuit between the positive electrode and the negative electrode may cause a fire explosion due to oxidation of lithium. Since there have been several explosion cases, the role of the membrane is very important in terms of stability. In particular, in the case of high-capacity batteries for automobiles that require high performance and high stability, the development of a separator having excellent characteristics is urgently needed.
현재 사용되는 분리막은 대부분 폴리올레핀 계열로 폴리에틸렌(Poly ethylene, PE), 폴리프로필렌(Poly propylene, PP)이 주로 사용되고 있다. 이는 다공성이어서 리튬 이온의 원활한 이동을 수행할 수 있고 우수한 기계적 물성을 가지고 있으나, 열적 안정성이 취약하고 액체 전해질에 대한 친화도가 낮아 이차전지의 안정성 및 성능을 제한시킬 수 있다.Most of the separators currently used are polyolefin-based, and polyethylene (PE) and polypropylene (PP) are mainly used. Since it is porous, it can perform smooth movement of lithium ions and has excellent mechanical properties. However, the thermal stability is poor and the affinity for the liquid electrolyte is low, thereby limiting the stability and performance of the secondary battery.
이를 개선하기 위하여 한국공개특허 제10-2011-0032227호에는 세라믹 입자를 사용하여 표면을 개질하였는데, 이는 분리막의 강도를 높이는데 효과적인 능력을 보여주었으나, 열적 안정성을 완벽하게 개선시키지 못하였고, 리튬 이차전지의 셀 조립시 분리막의 젖음성을 위해서는 추가 물질을 넣어주어야 하는 단점이 있다.In order to improve this, Korean Patent Publication No. 10-2011-0032227 modified the surface using ceramic particles, which showed an effective ability to increase the strength of the separator, but did not completely improve the thermal stability. When assembling the secondary battery, there is a disadvantage in that an additional material needs to be added for wettability of the separator.
따라서, 본 발명이 해결하고자 하는 첫 번째 과제는 리튬 이차전지 분리막에 있어서, 우수한 기계적 강도를 유지하면서 동시에 열적 안정성이 우수하여 셧-다운(shut-down) 효과와 멜트-다운(melt-down) 효과가 증진된 기능성 고분자를 이용한 리튬 이차전지용 다층구조 분리막을 제공하는 것이다.Therefore, the first problem to be solved by the present invention is a lithium secondary battery separator, while maintaining excellent mechanical strength and at the same time excellent thermal stability shut-down (shut-down) and melt-down (melt-down) effect It is to provide a multilayer structure separator for a lithium secondary battery using the enhanced functional polymer.
본 발명이 해결하고자 하는 두 번째 과제는 상기 기능성 고분자를 이용한 리튬 이차전지용 다층구조 분리막의 제조방법을 제공하는 것이다.The second problem to be solved by the present invention is to provide a method of manufacturing a multilayer structure separator for a lithium secondary battery using the functional polymer.
본 발명은 상기 첫 번째 과제를 달성하기 위하여,The present invention to achieve the first object,
폴리올레핀 계열의 고분자와 하기 [화학식 1]로 표시되는 화합물로 이루어진 리튬 이차전지용 분리막으로서,As a separator for a lithium secondary battery composed of a polyolefin-based polymer and a compound represented by the following [Formula 1],
상기 분리막은 제1층; 제2층; 및 상기 제1층과 제2층 사이에 존재하는 제3층;으로 이루어져 있고,The separator is a first layer; Second layer; And a third layer existing between the first layer and the second layer.
상기 제1층과 제2층은 하기 [화학식 1]로 표시되는 화합물층; 또는 하기 [화학식 1]로 표시되는 화합물로 코팅된 폴리올레핀 계열의 고분자층;이며, 제3층은 폴리올레핀 계열의 고분자층;이고The first layer and the second layer is a compound layer represented by the following [Formula 1]; Or a polyolefin-based polymer layer coated with a compound represented by the following [Formula 1], and the third layer is a polyolefin-based polymer layer;
상기 제1층, 제2층, 제3층을 부착하고 압착하기 전에, 상기 제1층과 제3층 사이 및 제2층과 제3층 사이에 접착물질이 도포되어 있고, 상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액이며,Before attaching and compressing the first layer, the second layer, and the third layer, an adhesive material is applied between the first layer and the third layer and between the second layer and the third layer, wherein the adhesive material is vinyl It is an aqueous polymer solution in which ethylene acetate is diluted in water,
상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 리튬 이차전지용 분리막을 제공한다.The polyolefin-based polymer provides a separator for a lithium secondary battery, characterized in that polyethylene or polypropylene.
화학식 1
Figure PCTKR2012008206-appb-C000001
 Formula 1
Figure PCTKR2012008206-appb-C000001
상기 [화학식 1]에서,In [Formula 1],
상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
또한, 본 발명은 폴리올레핀 계열의 고분자와 하기 [화학식 1]로 표시되는 화합물로 이루어진 리튬 이차전지용 분리막으로서,In addition, the present invention is a separator for a lithium secondary battery composed of a polyolefin-based polymer and a compound represented by the following [Formula 1],
상기 분리막은 제1층; 제2층; 및 상기 제1층과 제2층 사이에 존재하는 제3층;으로 이루어져 있고,The separator is a first layer; Second layer; And a third layer existing between the first layer and the second layer.
상기 제1층, 제2층 및 제3층은 각각 독립적으로 폴리올레핀 계열의 고분자층이며, 상기 분리막의 외부 표면은 하기 [화학식 1]로 표시되는 화합물로 코팅되어 있고,The first layer, the second layer and the third layer are each independently a polyolefin-based polymer layer, the outer surface of the separator is coated with a compound represented by the following [Formula 1],
상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 리튬 이차전지용 분리막을 제공하고,The polyolefin-based polymer provides a separator for a lithium secondary battery, characterized in that polyethylene or polypropylene,
상기 제1층 및 제2층은 폴리프로필렌 고분자층이고, 제3층은 폴리에틸렌 고분자층일 수 있으며, 상기 제3층과 접착하지 않는 제1층의 표면 및 상기 제3층과 접착하지 않는 제2층의 표면은 하기 [화학식 1]로 표시되는 화합물로 코팅될 수 있다. 즉, 분리막이 폴리올레핀 계열의 고분자층으로 적층되어 3층 구조로 이루어져 있고, 전체 분리막 외부 표면이 상기 [화학식 1]로 표시되는 화합물로 코팅될 수 있다.The first layer and the second layer may be a polypropylene polymer layer, and the third layer may be a polyethylene polymer layer, the surface of the first layer that does not adhere to the third layer, and the second layer that does not adhere to the third layer. The surface of may be coated with a compound represented by the following [Formula 1]. That is, the separator is laminated with a polyolefin-based polymer layer, and has a three-layer structure, and the entire outer surface of the separator may be coated with the compound represented by [Formula 1].
[화학식 1][Formula 1]
Figure PCTKR2012008206-appb-I000001
Figure PCTKR2012008206-appb-I000001
상기 [화학식 1]에서,In [Formula 1],
상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
본 발명의 일 실시예에 의하면, 상기 접착물질의 도포시에 본 발명에 따른 다공성 분리막의 공극 유지를 위하여 ultra air spraying, screen printing 또는 hydraulic spraying 방법으로 도포할 수 있고, 상기 도포된 접착물질의 입자 크기는 1-500 ㎛일 수 있다.According to an embodiment of the present invention, in order to maintain the pores of the porous membrane according to the present invention at the time of the application of the adhesive material can be applied by ultra air spraying, screen printing or hydraulic spraying method, the particles of the applied adhesive material The size may be 1-500 μm.
본 발명은 상기 두 번째 과제를 달성하기 위하여,The present invention to achieve the second object,
(a) 하기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계;(a) dissolving a compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution;
(b) 상기 고분자 용액을 유리판에 캐스팅하고, 건조하여 하기 [화학식 1]로 표시되는 화합물 필름을 제조하는 단계;(b) casting the polymer solution on a glass plate and drying to prepare a compound film represented by the following [Formula 1];
(c) 폴리올레핀 계열의 고분자 필름 위와 아래에 상기 [화학식 1]로 표시되는 화합물 필름을 위치시키고, 각 계면에 접착 물질을 도포한 후에 압착하여 3층으로 적층된 분리막을 제조하는 단계;를 포함하고,(c) placing a compound film represented by the above [Formula 1] on and below the polyolefin-based polymer film, applying an adhesive material to each interface, and then compressing the same to prepare a separator laminated in three layers. ,
상기 용매는 N-메틸-2-피롤리돈, 클로로포름, 테트라하이드로퓨란, 벤젠, 톨루엔 및 자일렌 중에서 선택되는 어느 하나이고,The solvent is any one selected from N-methyl-2-pyrrolidone, chloroform, tetrahydrofuran, benzene, toluene and xylene,
상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌이며The polyolefin-based polymer is polyethylene or polypropylene
상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액인 것을 특징으로 하는 이차전지용 분리막의 제조방법을 제공한다.The adhesive material provides a method of manufacturing a separator for a secondary battery, characterized in that the aqueous polymer solution diluted with vinyl ethylene acetate in water.
[화학식 1][Formula 1]
Figure PCTKR2012008206-appb-I000002
Figure PCTKR2012008206-appb-I000002
상기 [화학식 1]에서,In [Formula 1],
상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
본 발명의 일 실시예에 의하면, 상기 (a) 단계는 상기 용매의 빠른 증발 속도를 저지하기 위하여 추가적으로 부탄올 및 프로판올 중에서 선택되는 어느 하나의 비용매를 더 포함하여 교반할 수 있고, 상기 용매 : 비용매의 부피비는 1.5-4 : 1일 수 있다.According to an embodiment of the present invention, the step (a) may further include any one of non-solvents selected from butanol and propanol in order to prevent the fast evaporation rate of the solvent, and the solvent: cost The volume ratio of the hawk may be 1.5-4: 1.
본 발명의 다른 일 실시예에 의하면, 상기 (c) 단계에서 도포된 접착물질의 입자 크기는 본 발명에 따른 다공성 분리막의 공극 유지를 위하여 1-500 ㎛일 수 있다.According to another embodiment of the present invention, the particle size of the adhesive material applied in the step (c) may be 1-500 ㎛ to maintain the pore of the porous separator according to the invention.
본 발명의 다른 일 실시예에 의하면, 상기 (c) 단계에서 3층으로 적층된 분리막은 hot-pressing 방법으로 압착하여 제조할 수 있고, 120-130 ℃ 온도와 100-300 kg·f/cm2의 압력에서 1-5 초 동안 압착하여 3층으로 적층된 분리막을 제조할 수 있다.According to another embodiment of the present invention, the separator laminated in three layers in step (c) may be prepared by pressing by a hot-pressing method, the temperature 120-130 ℃ and 100-300 kg · f / cm 2 By pressing for 1-5 seconds at a pressure of can be prepared a separator laminated in three layers.
또한, 본 발명은 (d) 하기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계;In addition, the present invention (d) dissolving a compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution;
(e) 상기 고분자 용액을 폴리올레핀 계열의 고분자 필름에 코팅하여, 하기 [화학식 1]로 표시되는 화합물이 코팅된 폴리올레핀 계열의 고분자 필름을 제조하는 단계;(e) coating the polymer solution on a polyolefin-based polymer film to prepare a polyolefin-based polymer film coated with a compound represented by the following [Formula 1];
(f) 폴리올레핀 계열의 고분자 필름 위와 아래에 상기 [화학식 1]로 표시되는 화합물이 코팅된 고분자 필름을 위치시키고, 각 계면에 접착 물질을 도포한 후에 압착하여 3층으로 적층된 분리막을 제조하는 단계;를 포함하고,(f) placing a polymer film coated with the compound represented by the above [Formula 1] on and below the polyolefin-based polymer film, applying an adhesive material to each interface, and then compressing the same to prepare a separator laminated in three layers. Including;
상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌이며,The polyolefin-based polymer is polyethylene or polypropylene,
상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액인 것을 특징으로 하는 이차전지용 분리막의 제조방법을 제공한다.The adhesive material provides a method of manufacturing a separator for a secondary battery, characterized in that the aqueous polymer solution diluted with vinyl ethylene acetate in water.
[화학식 1][Formula 1]
Figure PCTKR2012008206-appb-I000003
Figure PCTKR2012008206-appb-I000003
상기 [화학식 1]에서,In [Formula 1],
상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
본 발명의 일 실시예에 의하면, 상기 (d) 단계에서의 용매는 폴리올레핀 계열의 고분자 필름에 코팅할 고분자 용액을 제조하기 위한 점에서 용매는 휘발성이 강한 클로로포름일 수 있다.According to one embodiment of the present invention, the solvent in the step (d) may be a volatile chloroform solvent in that the solvent for preparing a polymer solution to be coated on a polyolefin-based polymer film.
본 발명의 다른 일 실시예에 의하면, 상기 (e) 단계는 상기 고분자 용액을 폴리올레핀 계열의 고분자 필름에 코팅시 매우 얇은 층으로 코팅하기 위하여, 딥-코팅 방법을 사용할 수 있으며, 상기 딥-코팅의 속도는 8-9 mm/분일 수 있다.According to another embodiment of the present invention, in the step (e), in order to coat the polymer solution on a polyolefin-based polymer film in a very thin layer, a dip-coating method may be used, and the dip-coating of The speed can be 8-9 mm / minute.
본 발명의 다른 일 실시예에 의하면, 상기 (f) 단계에서 도포된 접착물질의 입자 크기는 본 발명에 따른 다공성 분리막의 공극 유지를 위하여 1-500 ㎛일 수 있다.According to another embodiment of the present invention, the particle size of the adhesive material applied in the step (f) may be 1-500 ㎛ to maintain the pore of the porous separator according to the invention.
본 발명의 다른 일 실시예에 의하면, 상기 (f) 단계에서 3층으로 적층된 분리막은 hot-pressing 방법으로 압착하여 제조할 수 있고, 120-130 ℃ 온도와 100-300 kg·f/cm2 의 압력에서 1-5 초 동안 압착하여 3층으로 적층된 분리막을 제조할 수 있다.According to another embodiment of the present invention, the separator laminated in three layers in the step (f) may be prepared by pressing by hot-pressing method, 120-130 ℃ temperature and 100-300 kg · f / cm 2 By pressing for 1-5 seconds at a pressure of can be prepared a separator laminated in three layers.
또한, 본 발명은 (g) 하기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계; 및In addition, the present invention (g) dissolving the compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution; And
(h) 3층으로 적층된 폴리올레핀 계열의 고분자 분리막의 표면을 하기 [화학식 1]로 표시되는 화합물로 코팅하는 단계;를 포함하고,(h) coating a surface of a polyolefin-based polymer separator laminated in three layers with a compound represented by the following [Formula 1]; and
상기 3층으로 적층된 폴리올레핀 계열의 고분자 분리막은 제1층; 제2층; 및 상기 제1층과 제2층 사이에 존재하는 제3층;으로 이루어져 있으며, 제3층의 위와 아래에 제1층과 제2층을 위치시키고, 각 계면에 접착물질을 도포한 후에 압착하여 제조하고,The polyolefin-based polymer separator laminated in three layers comprises a first layer; Second layer; And a third layer existing between the first layer and the second layer. The first layer and the second layer are positioned above and below the third layer, and the adhesive material is applied to each interface and then compressed. Manufacturing,
상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 이차전지용 분리막의 제조방법을 제공하고, 상기 제1층 및 제2층은 폴리프로필렌 고분자층이고, 제3층은 폴리에틸렌 고분자층일 수 있다.The polyolefin-based polymer provides a method for manufacturing a secondary battery separator, characterized in that the polyethylene or polypropylene, wherein the first layer and the second layer is a polypropylene polymer layer, the third layer may be a polyethylene polymer layer.
[화학식 1][Formula 1]
Figure PCTKR2012008206-appb-I000004
Figure PCTKR2012008206-appb-I000004
상기 [화학식 1]에서,In [Formula 1],
상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
다만, 상기 (g) 단계 및 (h) 단계를 포함하는 본 발명의 이차전지용 분리막의 제조방법에 있어서, 상기 제조방법에 한정하지 아니하고, 상기 [화학식 1]로 표시되는 화합물을 포함하는 고분자 용액을 상기 제1층 및 제2층의 양 표면 중 일 표면에 코팅하여 양 표면 중 일 표면이 [화학식 1]로 표시되는 화합물로 코팅된 제1층, 제2층 필름을 각각 제조한 후에, [화학식 1]로 표시되는 화합물로 코팅되지 않은 표면을 제3층에 각각 접착하여 분리막 전체 외부가 [화학식 1]로 표시되는 화합물로 코팅된 3층 구조로 적층된 분리막을 제조할 수 있다.However, in the method of manufacturing a secondary battery separator of the present invention comprising the steps (g) and (h), not limited to the production method, a polymer solution containing the compound represented by the above [Formula 1] After coating on one surface of both surfaces of the first layer and the second layer to prepare a first layer and a second layer film, each of which is coated with a compound represented by [Formula 1], one surface of both surfaces, A surface not coated with the compound represented by 1] may be adhered to the third layer, respectively, to prepare a separator laminated in a three-layer structure in which the entire exterior of the separator is coated with the compound represented by [Formula 1].
즉, 분리막이 폴리올레핀 계열의 고분자층으로 적층되어 3층 구조로 이루어져 있고, 전체 분리막 외부 표면이 상기 [화학식 1]로 표시되는 화합물로 코팅된 구조이면서 분리막의 특성이 동일하다면 본 발명의 범위에 포함된다 할 것이다.That is, if the separator is laminated with a polyolefin-based polymer layer is composed of a three-layer structure, and the entire outer surface of the separator is coated with a compound represented by the above [Formula 1] and the characteristics of the separator is included in the scope of the present invention Will be done.
본 발명에 따른 기능성 고분자를 이용한 리튬 이차전지용 다층구조 분리막은 낮은 열수축율과 향상된 난연성을 보여 열적 안정성이 매우 우수하며, 동시에 현재 상용화되어 있는 분리막과 동일한 수준의 높은 기공도와 우수한 기계적 물성을 보여 리튬 이차전지 분리막으로 직접 상용화하여 활용할 수 있다.The multilayered separator for a lithium secondary battery using the functional polymer according to the present invention exhibits low thermal shrinkage and improved flame retardancy, and thus has excellent thermal stability, and at the same time, shows high porosity and excellent mechanical properties similar to those of commercially available separators. It can be directly commercialized as a battery separator.
도 1a 내지 도 1c는 본 발명의 일 구현예에 따른 3층 구조로 적층된 리튬 이차전지용 분리막을 나타내는 개념도이다.1A to 1C are conceptual views illustrating separators for a lithium secondary battery stacked in a three-layer structure according to an embodiment of the present invention.
도 2a와 도 2b는 각각 본 발명의 실시예 1에 따라 제조한 분리막(BPPO-PE-BPPO)에 대한 표면 및 단면을 나타내는 SEM 이미지이다.2A and 2B are SEM images showing the surface and the cross section of the separator (BPPO-PE-BPPO) prepared according to Example 1 of the present invention, respectively.
도 2c 및 도 2d는 각각 본 발명의 실시예 2에 따라 제조한 분리막(BPPO가 코팅된 PP-PE-BPPO가 코팅된 PP)에 대한 표면 및 단면을 나타내는 SEM 이미지이다.2C and 2D are SEM images showing the surface and the cross-section of the separator (PP-PE-BPPO coated PP coated with BPPO) prepared according to Example 2 of the present invention, respectively.
도 2e 및 도 2f는 각각 본 발명의 실시예 3에 따라 제조한 BPPO가 코팅된 3층 적층(PP/PE/PP) 구조의 분리막에 대한 표면 및 단면을 나타내는 SEM 이미지이다.2E and 2F are SEM images showing a surface and a cross section of a separator of a BPPO-coated three-layer laminated (PP / PE / PP) structure prepared according to Example 3 of the present invention, respectively.
도 3은 실시예와 비교예에 따른 분리막에 대한 열수축 정도(thermal shrinkage)를 실험한 결과를 보여주는 이미지이다.3 is an image showing the results of experiments of the thermal shrinkage (thermal shrinkage) for the separator according to the Example and Comparative Example.
도 4는 실시예와 비교예에 따른 분리막에 대한 열수축 정도(thermal shrinkage)를 실험한 결과를 나타내는 그래프이다.4 is a graph showing the results of experiments on the thermal shrinkage (thermal shrinkage) for the separator according to the Example and Comparative Example.
도 5는 실시예와 비교예에 따른 분리막에 대한 인화성 실험 결과를 보여주는 이미지이다.5 is an image showing the results of the flammability test for the separator according to the Example and Comparative Example.
도 6은 본 발명에 따른 분리막을 사용하여 셀 테스트한 결과로서, 단위 용량에 따른 전위의 비교를 나타낸 그래프이다.6 is a graph showing a comparison of potentials according to unit capacity as a result of cell testing using the separator according to the present invention.
도 7a 및 7b는 본 발명에 따른 분리막을 사용하여 셀 테스트한 결과로서, 도 7a는 사이클 회수에 따른 상대적 용량률의 비교를 나타낸 그래프이고, 도 7b는 사이클 회수에 따른 쿨롱 효율의 비교를 나타낸 그래프이다.7A and 7B are cell test results using the separator according to the present invention. FIG. 7A is a graph showing a comparison of relative capacity ratios according to the number of cycles. to be.
이하, 본 발명을 더욱 상세하게 설명한다.Hereinafter, the present invention will be described in more detail.
본 발명은 종래 리튬 이차전지의 분리막에서 나타나는 열적 안정성과 액체 전해질에 대한 친화도 문제를 해결하기 위하여 기능성 고분자로서 하기 [화학식 1]로 표시되는 화합물(BPPO(brominated poly(phenylen oxide))과 폴리올레핀 계열의 고분자로 이루어지고, 다층 구조로 형성된 리튬 이차전지용 분리막을 제공한다.The present invention is a compound (BPPO (brominated poly (phenylen oxide)) and polyolefin-based compound represented by the following [Formula 1] as a functional polymer in order to solve the thermal stability and affinity for a liquid electrolyte in the separator of a conventional lithium secondary battery It is made of a polymer, and provides a separator for a lithium secondary battery formed in a multilayer structure.
[화학식 1][Formula 1]
Figure PCTKR2012008206-appb-I000005
Figure PCTKR2012008206-appb-I000005
상기 [화학식 1]에서, 상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.In Formula 1, r is 0 <r <1, and n is an integer between 1 and 5000.
상기 [화학식 1]로 표시되는 BPPO(brominated poly(phenylen oxide)) 화합물은 액체 전해질 첨가제와 유사한 분자 구조를 지니고 있어 젖음성이 양호하고, 또한 BPPO 구조의 브롬 작용기는 라디칼 반응을 저해하는 기능을 지니며 공극 내부에 존재하는 액체 전해질의 발화성을 감소시켜 결국, 리튬 이자전지의 폭발 위험을 저감시키는 역할을 한다.The brominated poly (phenylen oxide) (BPPO) compound represented by the above [Formula 1] has a molecular structure similar to that of a liquid electrolyte additive and has good wettability, and the bromine functional group of the BPPO structure has a function of inhibiting radical reaction. It reduces the ignition of the liquid electrolyte present in the voids, and eventually serves to reduce the explosion risk of the lithium rechargeable battery.
본 발명에 따른 분리막은 기계적 강도와, 분리막의 필수요소인 Shut down 효과(전지 과열시 미세기공폐쇄 기능)와 Melt down 효과(추가 온도 상승에도 필름 형태 유지)를 증진시키기 위하여 폴리올레핀 계열의 고분자와 함께 사용한 3층 구조의 분리막이다.The separator according to the present invention is combined with a polyolefin-based polymer to enhance mechanical strength, shut down effect (micropore closure function when the battery is overheated) and melt down effect (maintain film form even at an additional temperature increase), which are essential elements of the separator. It is the separator of the 3-layer structure used.
본 발명에 따른 다층 구조의 분리막은 폴리올레핀 계열의 고분자와 상기 [화학식 1]로 표시되는 화합물로 이루어진 리튬 이차전지용 분리막으로서, 상기 분리막은 제1층, 제2층 및 상기 제1층과 제2층 사이에 존재하는 제3층으로 이루어져 있고, 상기 제1층과 제2층은 상기 [화학식 1]로 표시되는 화합물층 또는 상기 [화학식 1]로 표시되는 화합물로 코팅된 폴리올레핀 계열의 고분자층이며, 제3층은 폴리올레핀 계열의 고분자층이고, 상기 제1층, 제2층, 제3층을 부착하고 압착하기 전에, 상기 제1층과 제3층 사이 및 제2층과 제3층 사이에 접착물질이 도포되어 있고, 상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액이며, 상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 한다.The multilayer membrane according to the present invention is a separator for a lithium secondary battery comprising a polyolefin-based polymer and the compound represented by the above [Formula 1], wherein the separator is a first layer, a second layer, and the first and second layers. It consists of a third layer present between, wherein the first layer and the second layer is a polyolefin-based polymer layer coated with a compound layer represented by the above [Formula 1] or a compound represented by the [Formula 1], The third layer is a polyolefin-based polymer layer, and an adhesive material between the first layer and the third layer and between the second layer and the third layer before attaching and compressing the first layer, the second layer, and the third layer. And the adhesive material is an aqueous polymer solution obtained by diluting vinyl ethylene acetate in water, and the polyolefin-based polymer is polyethylene or polypropylene.
또한, 본 발명에 따른 다층 구조의 분리막은 폴리올레핀 계열의 고분자와 상기 [화학식 1]로 표시되는 화합물로 이루어진 리튬 이차전지용 분리막으로서, 상기 분리막은 제1층, 제2층 및 상기 제1층과 제2층 사이에 존재하는 제3층으로 이루어져 있고, 상기 제1층, 제2층 및 제3층은 각각 독립적으로 폴리올레핀 계열의 고분자층이며, 상기 분리막의 외부 표면은 상기 [화학식 1]로 표시되는 화합물로 코팅되어 있는 것을 특징으로 한다.In addition, the multi-layer separator according to the present invention is a separator for a lithium secondary battery consisting of a polyolefin-based polymer and the compound represented by the above [Formula 1], the separator is a first layer, a second layer and the first layer and the first It consists of a third layer existing between the two layers, wherein the first layer, the second layer and the third layer are each independently a polyolefin-based polymer layer, the outer surface of the separator is represented by [Formula 1] It is characterized by being coated with a compound.
상기 제1층 및 제2층은 폴리프로필렌 고분자층이고, 제3층은 폴리에틸렌 고분자층일 수 있으며, 상기 제3층과 접착하지 않는 제1층의 표면 및 상기 제3층과 접착하지 않는 제2층의 표면은 상기 [화학식 1]로 표시되는 화합물로 코팅될 수 있다. 즉, 분리막이 폴리올레핀 계열의 고분자층으로 적층되어 3층 구조로 이루어져 있고, 전체 분리막 외부 표면이 상기 [화학식 1]로 표시되는 화합물로 코팅될 수 있다.The first layer and the second layer may be a polypropylene polymer layer, and the third layer may be a polyethylene polymer layer, the surface of the first layer that does not adhere to the third layer, and the second layer that does not adhere to the third layer. The surface of may be coated with a compound represented by the above [Formula 1]. That is, the separator is laminated with a polyolefin-based polymer layer, and has a three-layer structure, and the entire outer surface of the separator may be coated with the compound represented by [Formula 1].
하기 도 1a 및 도 1c의 개념도에서 보는 바와 같이, 본 발명의 일 실시예에서 3층 구조의 분리막은 BPPO/PE(폴리에틸렌)/BPPO 구조의 3층 구조 분리막과, BPPO가 코팅된 PP(폴리프로필렌)/PE/BPPO가 코팅된 PP 구조의 3층 구조 분리막 또는 분리막 외부 표면이 BPPO로 코팅되고, 폴리올레핀 계열의 고분자층으로 적층된 3층 구조 분리막(BPPO-PP/PE/PP-BPPO)일 수 있다.As shown in the conceptual diagrams of FIGS. 1A and 1C, in one embodiment of the present invention, the three-layer separator is a BPPO / PE (polyethylene) / BPPO-structured three-layer separator and PP (polypropylene) coated with BPPO. ) / PE / BPPO coated three-layer structure membrane of PP structure or the outer surface of the membrane may be a three-layer structure membrane (BPPO-PP / PE / PP-BPPO) coated with BPPO and laminated with a polyolefin-based polymer layer. have.
상기 적층 구조의 분리막에서 각 계면간의 접착시에는 분리막의 공극 유지를 위하여, 접착물질로는 비닐에틸렌아세테이트(vinyl ethylene acetate, VEA) 계열의 핫 멜티드용 접착제를 사용할 수 있고, 구체적인 접착제로서는 Air Product사의 Air flex EP 645, EP 705, EP 707K, 920 등이 있다. 상기 접착물질을 ultra air spraying, screen printing 또는 hydraulic spraying 방법으로 도포할 수 있고, 상기 도포된 접착물질의 입자 크기는 1-500 ㎛인 것이 바람직하다.In order to maintain the pores of the separator when the interface between the membranes of the laminated structure, the adhesive material may be a vinyl ethylene acetate (VEA) -based hot melt adhesive, and as a specific adhesive, Air Product Co., Ltd. Air flex EP 645, EP 705, EP 707K, 920 and the like. The adhesive material may be applied by ultra air spraying, screen printing or hydraulic spraying, and the particle size of the applied adhesive material is preferably 1-500 μm.
본 발명은 상기 다층 구조로 형성된 리튬 이차전지용 분리막의 제조방법을 제공하고, 기능성 고분자인 BPPO를 캐스팅 방법으로 필름을 제조하거나 또는 딥-코팅 방법으로 코팅하여 필름을 제조하는 과정, 이후 올레핀 계열 분리막과 접착하여 3층으로 적층 접착하는 과정으로 이루어지며, 그 제조방법의 세부적인 공정은 다음과 같다.The present invention provides a method of manufacturing a separator for a lithium secondary battery formed in the multilayer structure, and a process of preparing a film by casting a functional polymer BPPO or coating by a dip-coating method, after the olefin-based separator and It is made of a process of laminating and bonding in three layers by bonding, the detailed process of the manufacturing method is as follows.
(1) 상기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계,(1) dissolving the compound represented by the above [Formula 1] in a solvent and stirring to prepare a polymer solution,
(2) 상기 고분자 용액을 유리판에 캐스팅하고, 건조하여 상기 [화학식 1]로 표시되는 화합물 필름을 제조하는 단계, 또는 (2') 상기 고분자 용액을 폴리올레핀 계열의 고분자 필름에 코팅하여, 상기 [화학식 1]로 표시되는 화합물이 코팅된 폴리올레핀 계열의 고분자 필름을 제조하는 단계,(2) casting the polymer solution on a glass plate and drying to prepare a compound film represented by [Formula 1], or (2 ') coating the polymer solution on a polyolefin-based polymer film, Preparing a polyolefin-based polymer film coated with the compound represented by 1],
(3) 폴리올레핀 계열의 고분자 필름 위와 아래에 상기 [화학식 1]로 표시되는 화합물 필름 또는 상기 [화학식 1]로 표시되는 화합물이 코팅된 폴리올레핀 계열의 고분자 필름을 위치시키고, 각 계면에 접착 물질을 도포한 후에 압착하여 3층으로 적층된 분리막을 제조하는 단계로 이루어진다.(3) Place a compound film represented by the above [Formula 1] or a polyolefin-based polymer film coated with the compound represented by the above [Formula 1] on and below the polyolefin-based polymer film, and apply an adhesive substance to each interface. After the compression is made of a step of manufacturing a separator laminated in three layers.
상기 (1)에서의 고분자 용액을 제조하기 위한 용매는 N-메틸-2-피롤리돈, 클로로포름, 테트라하이드로퓨란, 벤젠, 톨루엔 및 자일렌 중에서 선택되는 어느 하나일 수 있고, 또한 상기 용매의 빠른 증발 속도를 저지하기 위하여 추가로 교반되는 비용매로서 부탄올 또는 프로판올을 첨가할 수 있고, 상기 용매 대 비용매의 부피비를 4 : 1 또는 3 : 2로 함이 바람직하다.The solvent for preparing the polymer solution in (1) may be any one selected from N-methyl-2-pyrrolidone, chloroform, tetrahydrofuran, benzene, toluene and xylene, and also the fast Butanol or propanol may be added as a non-solvent that is further stirred to counteract the rate of evaporation and the volume ratio of solvent to nonsolvent is preferably 4: 1 or 3: 2.
또한, (2')에서 폴리올레핀 계열의 고분자 필름에 코팅할 고분자 용액을 제조하기 위해서는 상기 (1)에서 사용하는 용매는 휘발성이 강한 클로로포름이 바람직하다.In addition, in order to prepare a polymer solution to be coated on the polyolefin-based polymer film in (2 '), the solvent used in the above (1) is preferably volatile volatile.
상기 (2')에서 고분자 용액을 폴리올레핀 계열의 고분자 필름에 코팅시 딥-코팅 방법을 사용하고, 상기 딥-코팅시 dipping 및 withdrawing 속도는 8-9 mm/분으로 함이 바람직하다.It is preferable to use a dip-coating method when coating the polymer solution on the polyolefin-based polymer film in (2 '), and the dipping and withdrawing speed is 8-9 mm / min during the dip-coating.
상기 (3)에서는 120-130 ℃ 온도와 100-300 kg·f/cm2 의 압력에서 1-5 초 동안 압착하는 것이 바람직하다.In said (3), it is preferable to crimp for 1-5 second at 120-130 degreeC temperature and the pressure of 100-300 kg.f / cm <2> .
또한, 본 발명에 따라 분리막 외부 표면이 BPPO로 코팅되고, 폴리올레핀 계열의 고분자층으로 적층된 3층 구조 분리막을 제조하는 방법은 (4) 하기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계와,In addition, according to the present invention, a method of manufacturing a three-layer structure membrane, in which the outer surface of the separator is coated with BPPO and laminated with a polyolefin-based polymer layer, (4) dissolving the compound represented by the following [Formula 1] in a solvent and stirring Preparing a polymer solution;
(5) 3층으로 적층된 폴리올레핀 계열의 고분자 분리막의 표면을 하기 [화학식 1]로 표시되는 화합물로 코팅하는 단계를 포함하는 것을 특징으로 한다.(5) characterized in that it comprises the step of coating the surface of the polyolefin-based polymer membrane laminated in three layers with a compound represented by the following [Formula 1].
상기 3층으로 적층된 폴리올레핀 계열의 고분자 분리막은 제1층; 제2층; 및 상기 제1층과 제2층 사이에 존재하는 제3층;으로 이루어져 있으며, 제3층의 위와 아래에 제1층과 제2층을 위치시키고, 각 계면에 접착물질을 도포한 후에 압착하여 제조한다.The polyolefin-based polymer separator laminated in three layers comprises a first layer; Second layer; And a third layer existing between the first layer and the second layer. The first layer and the second layer are positioned above and below the third layer, and the adhesive material is applied to each interface and then compressed. Manufacture.
또한, (4)에서 폴리올레핀 계열의 고분자 필름에 코팅할 고분자 용액을 제조하기 위해서는 상기 (4)에서 사용하는 용매는 휘발성이 강한 클로로포름이 바람직하다.In addition, in order to prepare a polymer solution to be coated on the polyolefin-based polymer film in (4), the solvent used in (4) is preferably volatile volatile.
상기 (5)에서 고분자 용액을 폴리올레핀 계열의 고분자 필름에 코팅시 딥-코팅 방법을 사용하고, 상기 딥-코팅시 dipping 및 withdrawing 속도는 8-9 mm/분으로 함이 모세관 현상에 따른 폴리머의 부착량을 최소화함으로써 본래 분리막이 가지고 있는 공극을 유지하기 위하여 바람직하다.In the above (5), a dip-coating method is used when the polymer solution is coated on a polyolefin-based polymer film, and the dipping and withdrawing speed is 8-9 mm / min during the dip-coating. It is desirable to maintain the pores of the original membrane by minimizing the
상기 (5) 단계 및 (6) 단계를 포함하는 본 발명의 이차전지용 분리막의 제조방법에 있어서, 상기 제조방법에 한정하지 아니하고, 상기 [화학식 1]로 표시되는 화합물을 포함하는 고분자 용액을 상기 제1층 및 제2층의 양 표면 중 일 표면에 코팅하여 양 표면 중 일 표면이 [화학식 1]로 표시되는 화합물로 코팅된 제1층, 제2층 필름을 각각 제조한 후에, [화학식 1]로 표시되는 화합물로 코팅되지 않은 표면을 제3층에 각각 접착하여 분리막 전체 외부가 [화학식 1]로 표시되는 화합물로 코팅된 3층 구조로 적층된 분리막을 제조할 수 있다.In the method for manufacturing a secondary battery separator of the present invention comprising the steps (5) and (6), not limited to the production method, the polymer solution containing the compound represented by the above [Formula 1] After coating on one of both surfaces of the first layer and the second layer to prepare a first layer and a second layer film each of which is coated with a compound represented by [Formula 1], one surface of both surfaces, [Formula 1] Each of the surfaces not coated with the compound represented by 3 may be adhered to the third layer to prepare a separator laminated in a three-layer structure in which the entire exterior of the separator is coated with the compound represented by [Formula 1].
즉, 분리막이 폴리올레핀 계열의 고분자층으로 적층되어 3층 구조로 이루어져 있고, 전체 분리막 외부 표면이 상기 [화학식 1]로 표시되는 화합물로 코팅된 구조이면서 분리막의 특성이 동일하다면 본 발명의 범위에 포함된다 할 것이다.That is, if the separator is laminated with a polyolefin-based polymer layer is composed of a three-layer structure, and the entire outer surface of the separator is coated with a compound represented by the above [Formula 1] and the characteristics of the separator is included in the scope of the present invention Will be done.
이하, 바람직한 실시예를 들어 본 발명을 더욱 상세하게 설명한다. 그러나, 이들 실시예는 본 발명을 보다 구체적으로 설명하기 위한 것으로, 본 발명의 범위가 이에 의하여 제한되지 않고, 본 발명의 범주 및 기술사상 범위 내에서 다양한 변경 및 수정이 가능함은 당업계의 통상의 지식을 가진 자에게 자명할 것이다.Hereinafter, the present invention will be described in more detail with reference to preferred examples. However, these examples are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited thereto, and various changes and modifications are possible within the scope and spirit of the present invention. It will be self-evident to those who have knowledge.
<실시예><Example>
실시예 1.Example 1.
(1) 본 발명에 따라 3층으로 이루어진 분리막의 제조는 기능성 고분자인 BPPO(brominated poly(phenylen oxide))를 이용한 다공성 분리막을 제조하는 단계와, 올레핀 계열의 분리막인 폴리에틸렌(Poly ethylene, PE)의 양 면에 BPPO 다공성 분리막을 적층한 3층 분리막 제조 단계로 구성되어 있다.(1) Preparation of a three-layer separator according to the present invention comprises the steps of preparing a porous separator using a functional polymer BPPO (brominated poly (phenylen oxide)), and the olefin-based separator of polyethylene (Poly ethylene, PE) It consists of a three-layer separator manufacturing step of laminating the BPPO porous separator on both sides.
(2) BPPO를 이용한 다공성 분리막 제조 단계(2) porous membrane manufacturing step using BPPO
BPPO 3 g을 N-메틸-2-피롤리돈 8 ml에 용해하고 부탄올 2 ml을 추가 교반하여 고분자 용액을 얻었다. 상기 얻어진 고분자 용액을 유리판에 닥터 블레이드로 캐스팅 한 후, 용매의 증발을 위해 대기 중에서 3 분 동안 건조하였다. 그 후, 증류수에 12 시간 동안 보관하여 상전이를 실시함으로써 다공성 고분자 분리막 필름을 제조하였다.3 g of BPPO was dissolved in 8 ml of N-methyl-2-pyrrolidone and 2 ml of butanol was further stirred to obtain a polymer solution. The obtained polymer solution was cast on a glass plate with a doctor blade, and then dried in air for 3 minutes to evaporate the solvent. Then, the porous polymer membrane film was prepared by carrying out phase transition by storing in distilled water for 12 hours.
(3) 3층 분리막의 제조 단계(3) manufacturing step of the three-layer separator
상기 실시예 1-(2)에서 제조된 단층 분리막(BPPO)을 제1층 및 제2층으로 바깥층으로 구성하고, PE를 제3층으로 하여 상기 제1층 및 제2층 사이에 존재하는 내층으로 하여 BPPO/PE/BPPO의 3층 적층계 구조로 접착하였다.The inner layer existing between the first layer and the second layer using the single layer separator (BPPO) prepared in Example 1- (2) as the first layer and the second layer as the outer layer, and the PE as the third layer. It adhere | attached by the 3-layer laminated structure of BPPO / PE / BPPO.
접착제는 Air flex EP 645를 1/2000 배로 희석하여 ultra air spray방법에 의해 제1층인 BPPO 분리막의 기준 면적 4 x 4 cm2 위에 0.5 ml의 접착제를 도포하였다. 먼저, 제3층인 PE의 윗면에 접착제를 도포하고 제1층을 적층한 후 뒤집어, 같은 방식으로 제3층의 뒷면에도 접착제를 도포하고 제2층을 적층하여, PE의 양면에 BPPO 단층 분리막을 순서대로 적층하였다. BPPO/PE/BPPO의 3층 적층계 구조는 120-130 ℃와 100-300 kg·f/cm2의 조건에서 hot pressing 기기를 사용하여 5 초 이내에서 순간적으로 접착하였다.The adhesive was diluted 1 / 2000-fold of Air flex EP 645 and 0.5 ml of adhesive was applied on the base area of 4 x 4 cm 2 of the BPPO membrane as the first layer by the ultra air spray method. First, the adhesive is applied to the upper surface of the PE, which is the third layer, the first layer is laminated, and then turned over. In the same manner, the adhesive is also applied to the back of the third layer and the second layer is laminated. It was laminated in order. The three-layer laminate structure of BPPO / PE / BPPO was instantaneously bonded within 5 seconds using a hot pressing machine at 120-130 ° C. and 100-300 kg · f / cm 2 .
실시예 2.Example 2.
(1) 본 발명에 따라 3층으로 이루어진 분리막의 제조는 기능성 고분자인 BPPO를 올레핀계 분리막인 폴리프로필렌(Poly propylene, PP) 표면에 딥-코팅하여 BPPO가 코팅된 PP의 다공성 분리막을 제조하는 단계와, 올레핀 계열의 분리막인 폴리에틸렌(Poly ethylene, PE)의 양 면에 BPPO가 코팅된 PP의 다공성 분리막을 적층한 3층 분리막 제조 단계로 구성되어 있다.(1) Preparation of a three-layer separator according to the present invention is to prepare a porous membrane of BPPO-coated PP by dip-coating the functional polymer BPPO on the surface of polypropylene (Poly propylene, PP), an olefin-based separator And, it is composed of a three-layer separator manufacturing step of laminating a porous separator of PP coated with BPPO on both sides of the polyethylene (Poly ethylene, PE) of the olefin-based separator.
(2) BPPO가 코팅된 PP의 다공성 분리막 제조(2) Preparation of porous membrane of PP coated with BPPO
BPPO 10 g을 Chloroform 50 ml에 용해하여 딥-코팅을 위한 고분자 용액을 제조하고, 올레핀 계열 분리막인 PP를 4 x 4 cm2의 사이즈로 잘라 준비된 고분자 용액에 8.56 mm/분의 속도로 dipping과 withdrawing을 차례대로 실행함으로써 PP표면에 얇게 BPPO를 코팅하여 BPPO가 코팅된 PP의 다공성 분리막을 제조하였다.10 g of BPPO was dissolved in 50 ml of chloroform to prepare a polymer solution for dip-coating, and PP, an olefin-based separator, was cut into 4 × 4 cm 2 sizes and dipping and withdrawing at a rate of 8.56 mm / min. By sequentially performing the BPPO coating on the surface of the PP thin to prepare a porous separator of PP coated with BPPO.
(3) 3층 분리막의 제조 단계(3) manufacturing step of the three-layer separator
상기 실시예 2-(2)에서 제조된 단층 분리막(BPPO가 코팅된 PP의 다공성 분리막)을 제1층 및 제2층으로 바깥층으로 구성하고, PE를 제3층으로 하여 상기 제1층 및 제2층 사이에 존재하는 내층으로 하여, BPPO coated PP/PE/BPPO coated PP의 3층 적층계 구조로 접착하였다.The monolayer separator prepared in Example 2- (2) (porous separator of PP coated with BPPO) is composed of an outer layer as a first layer and a second layer, and the first layer and the first layer using PE as a third layer. As the inner layer existing between the two layers, it was bonded in a three-layer laminate structure of BPPO coated PP / PE / BPPO coated PP.
접착제는 Air flex EP 645를 1/2000 배로 희석하여 ultra air spray방법에 의해 제1층인 BPPO가 코팅된 PP의 다공성 분리막의 기준 면적 4 x 4 cm2 위에 0.5 ml의 접착제를 도포하였다. 그 후, 제3층인 PE를 올려 놓은 후, 120-130 에서 hot pressing을 사용하여 접착하였다. 또한, 상기 제3층과 제2층의 분리막도 같은 방식으로 접착하여 3층 분리막을 제조하였다.The adhesive was diluted with air flex EP 645 by 1/2000 times and 0.5 ml of adhesive was applied onto the reference area of 4 x 4 cm 2 of the porous membrane of BPPO-coated PP as the first layer by ultra air spray method. Thereafter, the third layer of PE was put on, and then bonded using hot pressing at 120-130. In addition, the separator of the third layer and the second layer was also bonded in the same manner to prepare a three-layer separator.
실시예 3.Example 3.
(1) 3층으로 적층(PP/PE/PP)된 폴리올레핀 계열의 고분자 분리막 제조 단계(1) Polyolefin-based polymer membrane manufacturing step laminated in three layers (PP / PE / PP)
Celgard 2340(PP/PE/PP)과 동일하게 바깥층인 제1층 및 제2층을 PP로 하고, 내층인 제3층을 PE로 하여 상기 실시예 1-(3)과 동일한 방법으로 제조하였다.In the same manner as in Celgard 2340 (PP / PE / PP), the first and second layers of the outer layer were made of PP, and the inner layer of the third layer was made of PE, using the same method as in Example 1- (3).
(2) BPPO로 코팅된 3층 적층 고분자 분리막 제조 단계(2) step of manufacturing a three-layer laminated polymer membrane coated with BPPO
BPPO 10 g을 Chloroform 50 ml에 용해하여 딥코팅을 위한 고분자 용액을 제조하고, 상기 제조된 tri-layer(PP/PE/PP, Celgard 2340)를 원하는 사이즈로 잘라 준비된 고분자 용액에 8.56 mm/분의 속도로 dipping과 withdrawing을 차례대로 수행하여 tri-layer 표면에 얇게 BPPO를 코팅하였다. 10 g of BPPO was dissolved in 50 ml of Chloroform to prepare a polymer solution for dip coating, and the prepared tri-layer (PP / PE / PP, Celgard 2340) was cut into a desired size and prepared in a polymer solution of 8.56 mm / min. Dipping and withdrawing were carried out in turn and thinly coated BPPO on the tri-layer surface.
비교예 1.Comparative Example 1.
상용화된 올레핀 계열의 폴리프로필렌을 고분자 시트로 단일층으로 하여 25 두께의 분리막을 사용하였다.A membrane having a thickness of 25 was used as a single layer of a commercially available olefin-based polypropylene as a polymer sheet.
비교예 2.Comparative Example 2.
상용화된 올레핀 계열의 폴리프로필렌과 폴리에틸렌을 사용하여 3층으로 적층된 PP/PE/PP(Celgard 2340)의 3층 분리막을 사용하였다.A three-layer membrane of PP / PE / PP (Celgard 2340) laminated in three layers using polypropylene and polyethylene of commercial olefin series was used.
실험예 1.Experimental Example 1.
상기 실시예 1 내지 실시예 3에 따라 제조한 3층 구조의 분리막에 대해서 표면 및 단면에 대해서 주사전자현미경으로 확인하였고, 이에 대해서 하기 도 2a 내지 도 2f에 나타내었다.For the separator of the three-layer structure prepared according to Examples 1 to 3 was confirmed by scanning electron microscopy on the surface and the cross-section, it is shown in Figure 2a to 2f.
하기 도 2a(상기 실시예 1에 따라 제조된 분리막의 표면) 및 하기 도 2c(상기 실시예 2에 따라 제조된 분리막의 표면)에서 보는 바와 같이, 본 발명에 따라 제조된 분리막은 다공성이어서 분리막으로서 리튬이온의 이동이 가능함을 보여주며, 하기 도 2b(상기 실시예 1에 따라 제조된 분리막의 단면) 및 하기 도 2d(상기 실시예 2에 따라 제조된 분리막의 단면)에서 보는 바와 같이, 본 발명에 따라 제조된 분리막은 3층 구조로 적층이 이루어져 있음을 알 수 있다.As shown in FIG. 2A (the surface of the separator prepared in accordance with Example 1) and FIG. 2C (the surface of the separator prepared in Example 2) below, the separator prepared in accordance with the present invention is porous and thus as a separator. It is shown that the movement of lithium ions, as shown in Figure 2b (cross section of the separator prepared according to Example 1) and Figure 2d (cross section of the separator prepared according to Example 2) below, the present invention It can be seen that the separator prepared according to the lamination is made of a three-layer structure.
또한, 하기 도 2e(상기 실시예 3에 따라 제조된 분리막의 표면) 및 도 2f(상기 실시예 3에 따라 제조된 분리막의 단면)에서 보는 바와 같이, 3층 구조로 적층되어 있으며, 공극이 연결되어 있음을 확인할 수 있다.In addition, as shown in FIG. 2E (the surface of the separator prepared according to Example 3) and FIG. 2F (the cross section of the separator prepared according to Example 3) below, the layer is laminated in a three-layer structure, and the pores are connected. It can be confirmed.
실험예 2. Porosity 분석Experimental Example 2. Porosity Analysis
(1) 본 발명에 따라 3층 구조로 적층하여 제조한 분리막의 porosity 유지를 확인하기 위하여 본 발명에 따라 제조된 3층 구조의 분리막인 실시예 1 내지 실시예 3과, 상용화된 비교예와 비교하여 공기투과도 및 porosity를 확인하였다.(1) Example 1 to Example 3, which is a separator having a three-layer structure manufactured according to the present invention, in order to confirm the porosity retention of the separator prepared by laminating in a three-layer structure according to the present invention, compared with a commercialized comparative example Air permeability and porosity was confirmed.
(2) 공기투과도는 지름 13 mm의 준비된 분리막에 일정한 공기압을 통과시켜 통과된 기압을 bubble meter로 측정하여 Gurley값을 계산하였다. 하기 [표 1]은 실시예 1 내지 3과 비교예의 공기투과도 결과를 나타낸 것이다.(2) Air permeability was calculated by passing a constant air pressure through a prepared membrane of 13 mm in diameter by measuring the air pressure passed by a bubble meter to calculate the Gurley value. Table 1 shows the air permeability results of Examples 1 to 3 and Comparative Examples.
표 1
구분 실시예 1 실시예 2 실시예 3 비교예 1
Gurley (s/100 cc) 144.0 144.0 143.9 144.2
Table 1
division Example 1 Example 2 Example 3 Comparative Example 1
Gurley (s / 100 cc) 144.0 144.0 143.9 144.2
상기 [표 1]에서 보는 바와 같이, 본 발명에 따른 실시예와 비교예가 큰 차이를 보이지 않기 때문에 porosity가 잘 유지됨 알 수 있다. 이에 따라 본 발명에 따른 분리막이 배터리 운전시 상용화된 분리막과 비슷한 리튬이온의 이동성을 나타냄을 의미한다.As shown in Table 1, it can be seen that the porosity is well maintained because the Examples and Comparative Examples according to the present invention do not show a large difference. This means that the separator according to the present invention exhibits mobility of lithium ions similar to the separator commercialized during battery operation.
(3) Porosity 실험은 미네랄 오일을 사용하여 제조된 분리막의 오일의 함유 정도를 무게로 측정하여 porosity를 계산하였다. 하기 [표 2]는 실시예 1 내지 실시예 3, 비교예에 대한 porosity의 결과를 나타낸 것이다.(3) Porosity In the experiment, the porosity was calculated by measuring the oil content of the membrane prepared by using mineral oil by weight. Table 2 below shows the results of porosity for Examples 1 to 3 and Comparative Examples.
표 2
구분 실시예 1 실시예 2 실시예 3 비교예 2
Porosity(%) 31.1 30.6 26.2 31.8
TABLE 2
division Example 1 Example 2 Example 3 Comparative Example 2
Porosity (%) 31.1 30.6 26.2 31.8
상기 [표 2]에서 보는 바와 같이, 실시예와 비교예의 값이 큰 차이를 보이지 않는 것으로 볼 때, 3층 구조로 적층시 접착제의 영향은 거의 없음을 알 수 있으며, 실시예 2 내지 실시예 3의 porosity가 비교예에 비하여 다소 낮은 것은 BPPO의 코팅으로 인한 공극 크기의 감소 때문이기는 하나, 거의 동일 수준에서 porosity가 잘 유지됨을 알 수 있고, 따라서, 이는 상용화된 분리막과 동일한 수준의 성능을 보이는 것으로서, 본 발명에 따라 제조된 분리막이 상용화된 분리막을 대체할 수 있을 정도로 실용화 가능성이 충분함을 보여주는 것이다.As shown in [Table 2], when the value of the Example and the comparative example does not show a large difference, it can be seen that the effect of the adhesive when laminating in a three-layer structure, Examples 2 to 3 The porosity of is somewhat lower than that of the comparative example due to the decrease in pore size due to the coating of BPPO, but the porosity is well maintained at about the same level. In addition, the separator prepared according to the present invention shows that the possibility of practical use is sufficient to replace the commercially available separator.
실험예 3. 분리막의 열적 안정성 테스트Experimental Example 3. Thermal Stability Test of Membrane
(1) 본 발명에 따른 기능성 고분자 분리막에 대해서 열적 안정성을 확인하기 위하여 상기 실시예와 비교예를 사용하여 thermal shrinkage실험과 인화성 실험을 실시하였다.(1) In order to confirm thermal stability of the functional polymer membrane according to the present invention, thermal shrinkage experiments and flammability experiments were performed using the above examples and comparative examples.
(2) Thermal shrinkage 실험은 100-200 ℃ 범위의 다양한 온도 조건에서 30 분 동안 샘플에 열을 가해서 변화한 샘플의 길이를 측정하여 수축 정도를 계산하였다. 하기 도 3은 초기 조건의 샘플과 180 ℃ 처리 후 샘플의 사진이다. 하기 도 3의 좌측 사진은 아무런 열적 조건을 주지 않은 상태에서 4 x 4 cm2 의 면적으로 준비한 것이고, 우측 사진은 180 ℃의 처리 후의 것으로서, 열처리 후 수축 정도를 보여주고 있다. 비교예 2의 경우는 매우 투명해진 상태를 보여주고 있는데, 이는 분리막의 공극이 완전히 막혔음을 의미하는 것이고, 200 ℃의 경우에는 비교예 2의 분리막이 완전 녹았기 때문에 이미지로 나타내지 않았다.(2) Thermal shrinkage experiments calculated the shrinkage by measuring the length of the changed sample by applying heat to the sample for 30 minutes at various temperature conditions in the range of 100-200 ℃. 3 is a photograph of the sample under initial conditions and the sample after 180 ° C. treatment. The left picture of FIG. 3 is prepared with an area of 4 × 4 cm 2 without any thermal condition, and the right picture shows the degree of shrinkage after heat treatment as it is after 180 ° C. treatment. Comparative Example 2 shows a very transparent state, which means that the pores of the separator is completely blocked, and in the case of 200 ° C., the separator of Comparative Example 2 was not melted, and thus was not shown in the image.
또한, 하기 도 4에 분리막 면적의 변화를 측정하여 thermal shrinkage를 각 온도의 조건에 따라 백분율로 나타내었다.In addition, in Figure 4 below, the change in the membrane area was measured, and thermal shrinkage was expressed as a percentage according to the conditions of each temperature.
하기 도 3 및 도 4에서 보는 바와 같이, 비교예 2는 71.1%, 실시예 1은 4.9%, 실시예 3은 50.1%의 열적 수축성을 나타내어 비교예의 샘플이 실시예 1과 실시예 3에 비하여 열적 수축성이 크다는 것을 확인할 수 있다.As shown in Figures 3 and 4 below, Comparative Example 2 shows a thermal shrinkage of 71.1%, Example 1 is 4.9%, Example 3 is 50.1% so that the sample of the Comparative Example is more thermally compared to Examples 1 and 3 It can be seen that the shrinkage is large.
실시예 1의 경우에는 3층 분리막의 적층이 매우 잘되어 있는 상태이기 때문에 BPPO 분리막의 사이에 있는 PE가 수축되더라도 양측에 있는 BPPO 분리막이 단단히 받쳐주고 있어 매우 향상된 열적 안정성을 보여주고 있다. 이는 본 발명에서 사용된 기능성 고분자의 열적 안정성 특성으로 인하여 분리막의 열적 수축성이 크게 개선되었음을 보여주는 것이다. 즉, 본 발명에 따른 분리막이 상용화된 분리막에 비하여 고온에서 열적 안정성이 보다 우수하다는 것을 알 수 있다.In the case of Example 1, since the lamination of the three-layer separator is very well, the BPPO separators on both sides are firmly supported even if the PE between the BPPO separators is contracted, thereby showing very improved thermal stability. This shows that the thermal shrinkage of the separator is greatly improved due to the thermal stability of the functional polymer used in the present invention. That is, it can be seen that the thermal stability at a high temperature is superior to that of the separator according to the present invention commercially available.
(3) 인화성 실험은 분리막을 전해질로 적신 후 표면에 묻은 전해질만 제거하고 불을 붙여 실행하였다. 이는 연소가 시작할 때부터 완전히 불이 꺼질 때까지의 인화 시간을 측정하였고, 완전 연소 후 분리막의 남은 상태를 확인하였다. 시간에 따른 연소과정은 하기 도 5에 나타내었다.(3) Flammability test was performed by wetting the separator with electrolyte, removing only the electrolyte on the surface, and lighting it. It measured the ignition time from the start of combustion until it completely turned off and confirmed the remaining state of the separator after complete combustion. The combustion process over time is shown in FIG. 5.
하기 도 5에서 보는 바와 같이, 연소가 시작되고 실시예 1은 4 초, 실시예 2는 9 초 내에 연소가 중지되었으며, 분리막내 전해질의 연소 후에 분리막의 형태가 일부분 남아있다. 이에 반하여, 비교예 2의 경우 연소가 시작하여 2 초 후에 분리막이 분리되어 길게 녹아내리고, 연소과정에서는 리튬의 산화로 인한 스파크의 발생도 확인할 수 있었다. 또한, 연소가 끝난 후 분리막은 완전 연소되어 형태가 없어졌다.As shown in FIG. 5, combustion started and Example 1 stopped combustion in 4 seconds, Example 2 in 9 seconds, and part of the separator remained after combustion of the electrolyte in the separator. On the contrary, in the case of Comparative Example 2, the separation membrane was separated and melted for 2 seconds after the start of combustion, and spark generation due to oxidation of lithium was also confirmed during the combustion process. In addition, after the combustion was completed, the membrane was completely burned out.
이는 본 발명에서 사용된 기능성 고분자의 난연성 특성에 따라 분리막 내의 리튬염을 포함하는 전해질을 안정적으로 연소시키며, 연소 후에도 분리막의 잔해를 남김으로써, 리튬이온전지의 폭발시 접촉단락을 오랫동안 방지하여 열적 안정성이 매우 우수함을 보여주는 것이다.This stably combusts the electrolyte containing the lithium salt in the separator according to the flame retardant properties of the functional polymer used in the present invention, and leaves a residue of the separator even after combustion, thereby preventing contact short-circuit during explosion of the lithium ion battery for a long time, thereby ensuring thermal stability. This is very good.
실험예 4. 셀 테스트Experimental Example 4. Cell Test
(1) 본 발명에 따른 분리막을 사용하여 충·방전 효과를 확인하기 위하여 CR2032규격의 coin cell을 제작하여 반복적인 cell test를 수행하였다.(1) In order to confirm the charging and discharging effect using the separator according to the present invention, a coin cell of the CR2032 standard was manufactured and repeated cell tests were performed.
(2) Coin cell은 cathode에 LiCoO2의 양극 활물질과 anode에 Li metal을 사용하였고, 1 M LiPF6 in EC/DEC 1:1 용액을 전해질로 사용하였다. 셀 조립은 아르곤 가스가 치환되어 있는 글러브 박스 안에서 진행하였다. 셀 테스트의 충전과 방전 전압은 4.2 V에서 3.0 V사이로 지정하였고, 0.1 C의 속도로 충·방전을 10 회 반복하여 단위 용량 및 상대적 용량률과 쿨롱 효율을 확인하였다. 그 결과를 하기 도 6 및 도 7에 나타내었다.(2) Coin cell used LiCoO 2 cathode active material for cathode and Li metal for anode, and 1 M LiPF 6 in EC / DEC 1: 1 solution was used as electrolyte. Cell assembly was carried out in a glove box in which argon gas was substituted. The charge and discharge voltages of the cell test were set between 4.2 V and 3.0 V, and the charge and discharge were repeated 10 times at a rate of 0.1 C to confirm the unit capacity, the relative capacity ratio, and the coulomb efficiency. The results are shown in FIGS. 6 and 7.
하기 도 6은 실시예 1, 3과 비교예 2의 테스트 결과를 용량에 따른 전위(potential)로 나타낸 것이고, 10 번째 사이클의 충·방전 그래프를 나타낸 것이다. 그 결과, 실시예 1, 3 그리고 비교예 2의 방전 용량은 각각 126.6 mAh/g, 124.2 mAh/g, 그리고 124.4 mAh/g로 나타남으로써 본 발명으로 제조된 분리막인 실시예 1은 상용화된 분리막보다 용량이 더 높게 나왔고, 실시예 3은 상용화된 분리막의 셀 테스트와 거의 대등한 용량을 나타내고 있음을 확인할 수 있다.6 shows the test results of Examples 1 and 3 and Comparative Example 2 as potentials according to the capacity, and shows a charge / discharge graph of the 10th cycle. As a result, the discharge capacities of Examples 1, 3 and Comparative Example 2 were represented by 126.6 mAh / g, 124.2 mAh / g, and 124.4 mAh / g, respectively. It was found that the capacity was higher, and Example 3 showed almost the same capacity as the cell test of a commercially available separator.
이는 기존 폴리올레핀 계열의 분리막보다 기능성 고분자 분리막의 큰 공극(pore) 크기에 기인하는 것이며, BPPO의 성질에 따라 전해질에 대한 젖음성이 뛰어나 단위 용량에서 보다 향상된 결과가 나타난 것이다. 방전의 경우, 실시예 1, 3의 방전 그래프가 비교예 2의 방전 그래프보다 천천히 떨어짐을 확인할 수 있는데 이에 의해서 방전효율도 역시 보다 개선되었음을 알 수 있다.This is due to the larger pore size of the functional polymer membrane than the conventional polyolefin-based membrane, and the wettability of the electrolyte is excellent according to the properties of the BPPO, which is more improved in the unit capacity. In the case of discharge, it can be seen that the discharge graphs of Examples 1 and 3 fall more slowly than the discharge graphs of Comparative Example 2, whereby the discharge efficiency is also improved.
하기 도 7a 및 7b는 실시예 1, 3의 리튬 이차전지와 비교예 2의 리튬 이차전지의 사이클 회수에 따른 상대적 용량률과 쿨롱 효율을 도시한 그래프로서, 하기 도 7a 및 7b에서 보는 바와 같이, 본 발명에 따른 실시예 1의 분리막이 적용된 리튬 이차전지는 충·방전 사이클 횟수가 증가함에 따라 상대적인 용량률 및 쿨롱 효율이 높음을 알 수 있다. 또한, 본 발명에 따른 실시예 3의 분리막이 적용된 리튬 이차전지는 충·방전 사이클 횟수가 증가함에 따라 비교예 2의 이차전지와 비슷한 수준의 상대적 용량을 가지며, 쿨롱 효율은 높음을 알 수 있다.7A and 7B are graphs showing relative capacity ratios and coulombic efficiencies according to cycle times of the lithium secondary batteries of Examples 1 and 3 and the lithium secondary batteries of Comparative Example 2, as shown in FIGS. 7A and 7B. It can be seen that the lithium secondary battery to which the separator of Example 1 according to the present invention is applied has a high relative capacity rate and coulombic efficiency as the number of charge and discharge cycles increases. In addition, it can be seen that the lithium secondary battery to which the separator of Example 3 according to the present invention is applied has a relative capacity similar to that of the secondary battery of Comparative Example 2 as the number of charge and discharge cycles increases, and the coulombic efficiency is high.
따라서, 상용화된 분리막과 비교시 본 발명에 따른 분리막이 적용된 리튬 이차전지의 성능이 보다 향상되거나 대등한 효율을 가지고 있어서, 비교예의 분리막을 대체하여 리튬 이차전지로 충분히 사용이 가능함을 알 수 있다.Therefore, the performance of the lithium secondary battery to which the separator according to the present invention is applied is more improved or comparable to that of the commercially available separator, and thus, it can be seen that the lithium secondary battery can be sufficiently used as a replacement of the separator of the comparative example.

Claims (25)

  1. 폴리올레핀 계열의 고분자와 하기 [화학식 1]로 표시되는 화합물로 이루어진 리튬 이차전지용 분리막으로서,As a separator for a lithium secondary battery composed of a polyolefin-based polymer and a compound represented by the following [Formula 1],
    상기 분리막은 제1층; 제2층; 및 상기 제1층과 제2층 사이에 존재하는 제3층;으로 이루어져 있고,The separator is a first layer; Second layer; And a third layer existing between the first layer and the second layer.
    상기 제1층과 제2층은 하기 [화학식 1]로 표시되는 화합물층; 또는 하기 [화학식 1]로 표시되는 화합물로 코팅된 폴리올레핀 계열의 고분자층;이며, 제3층은 폴리올레핀 계열의 고분자층;이고The first layer and the second layer is a compound layer represented by the following [Formula 1]; Or a polyolefin-based polymer layer coated with a compound represented by the following [Formula 1], and the third layer is a polyolefin-based polymer layer;
    상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 리튬 이차전지용 분리막.The polyolefin-based polymer is a lithium secondary battery separator, characterized in that the polyethylene or polypropylene.
    [화학식 1][Formula 1]
    Figure PCTKR2012008206-appb-I000006
    Figure PCTKR2012008206-appb-I000006
    상기 [화학식 1]에서,In [Formula 1],
    상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
  2. 제 1 항에 있어서,The method of claim 1,
    상기 제1층, 제2층, 제3층을 부착하고 압착하기 전에, 상기 제1층과 제3층 사이 및 제2층과 제3층 사이에 접착물질이 도포되어 있고, 상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액인 것을 특징으로 하는 리튬 이차전지용 분리막.Before attaching and compressing the first layer, the second layer, and the third layer, an adhesive material is applied between the first layer and the third layer and between the second layer and the third layer, wherein the adhesive material is vinyl Separation membrane for a lithium secondary battery, characterized in that the polymer solution diluted with water ethylene acetate.
  3. 제 1 항에 있어서,The method of claim 1,
    상기 도포된 접착물질의 입자 크기는 1-500 ㎛인 것을 특징으로 하는 리튬 이차전지용 분리막.Separation membrane for a lithium secondary battery, characterized in that the particle size of the applied adhesive material is 1-500 ㎛.
  4. 폴리올레핀 계열의 고분자와 하기 [화학식 1]로 표시되는 화합물로 이루어진 리튬 이차전지용 분리막으로서,As a separator for a lithium secondary battery composed of a polyolefin-based polymer and a compound represented by the following [Formula 1],
    상기 분리막은 제1층; 제2층; 및 상기 제1층과 제2층 사이에 존재하는 제3층;으로 이루어져 있고,The separator is a first layer; Second layer; And a third layer existing between the first layer and the second layer.
    상기 제1층, 제2층 및 제3층은 각각 독립적으로 폴리올레핀 계열의 고분자층이며, 상기 분리막의 외부 표면은 하기 [화학식 1]로 표시되는 화합물로 코팅되어 있고,The first layer, the second layer and the third layer are each independently a polyolefin-based polymer layer, the outer surface of the separator is coated with a compound represented by the following [Formula 1],
    상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 리튬 이차전지용 분리막.The polyolefin-based polymer is a lithium secondary battery separator, characterized in that the polyethylene or polypropylene.
    [화학식 1][Formula 1]
    Figure PCTKR2012008206-appb-I000007
    Figure PCTKR2012008206-appb-I000007
    상기 [화학식 1]에서,In [Formula 1],
    상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다R is 0 <r <1, and n is an integer between 1 and 5000
  5. 제 4 항에 있어서,The method of claim 4, wherein
    상기 제1층 및 제2층은 폴리프로필렌 고분자층이고, 제3층은 폴리에틸렌 고분자층이며, 상기 제3층과 접착하지 않는 제1층의 표면 및 상기 제3층과 접착하지 않는 제2층의 표면은 상기 [화학식 1]로 표시되는 화합물로 코팅되어 있는 것을 특징으로 하는 리튬 이차전지용 분리막.The first layer and the second layer are polypropylene polymer layers, the third layer is a polyethylene polymer layer, and the surface of the first layer that does not adhere to the third layer and the second layer that does not adhere to the third layer. Separation membrane for a lithium secondary battery, characterized in that the surface is coated with a compound represented by the above [Formula 1].
  6. 제 4 항에 있어서,The method of claim 4, wherein
    상기 제1층, 제2층, 제3층을 부착하고 압착하기 전에, 상기 제1층과 제3층 사이 및 제2층과 제3층 사이에 접착물질이 도포되어 있고, 상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액인 것을 특징으로 하는 리튬 이차전지용 분리막.Before attaching and compressing the first layer, the second layer, and the third layer, an adhesive material is applied between the first layer and the third layer and between the second layer and the third layer, wherein the adhesive material is vinyl Separation membrane for a lithium secondary battery, characterized in that the polymer solution diluted with water ethylene acetate.
  7. 제 4 항에 있어서,The method of claim 4, wherein
    상기 도포된 접착물질의 입자 크기는 1-500 ㎛인 것을 특징으로 하는 리튬 이차전지용 분리막.Separation membrane for a lithium secondary battery, characterized in that the particle size of the applied adhesive material is 1-500 ㎛.
  8. (a) 하기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계;(a) dissolving a compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution;
    (b) 상기 고분자 용액을 유리판에 캐스팅하고, 건조하여 하기 [화학식 1]로 표시되는 화합물 필름을 제조하는 단계;(b) casting the polymer solution on a glass plate and drying to prepare a compound film represented by the following [Formula 1];
    (c) 폴리올레핀 계열의 고분자 필름 위와 아래에 상기 [화학식 1]로 표시되는 화합물 필름을 위치시키고, 각 계면에 접착 물질을 도포한 후에 압착하여 3층으로 적층된 분리막을 제조하는 단계;를 포함하고,(c) placing a compound film represented by the above [Formula 1] on and below the polyolefin-based polymer film, applying an adhesive material to each interface, and then compressing the same to prepare a separator laminated in three layers. ,
    상기 용매는 N-메틸-2-피롤리돈, 클로로포름, 테트라하이드로퓨란, 벤젠, 톨루엔 및 자일렌 중에서 선택되는 어느 하나이며,The solvent is any one selected from N-methyl-2-pyrrolidone, chloroform, tetrahydrofuran, benzene, toluene and xylene,
    상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The polyolefin-based polymer is a method for producing a secondary battery separator, characterized in that the polyethylene or polypropylene.
    [화학식 1][Formula 1]
    Figure PCTKR2012008206-appb-I000008
    Figure PCTKR2012008206-appb-I000008
    상기 [화학식 1]에서,In [Formula 1],
    상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
  9. 제 8 항에 있어서,The method of claim 8,
    상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The adhesive material is a manufacturing method of a secondary battery separator, characterized in that the aqueous polymer solution diluted with vinyl ethylene acetate in water.
  10. 제 8 항에 있어서,The method of claim 8,
    상기 (a) 단계는 부탄올 및 프로판올 중에서 선택되는 어느 하나의 비용매를 더 포함하여 교반하고, 상기 용매 : 비용매의 부피비는 1.5-4 : 1인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The step (a) further comprises any one of a non-solvent selected from butanol and propanol, stirring, the volume ratio of the solvent: non-solvent is a method of manufacturing a secondary battery separator, characterized in that 1.5-4: 1.
  11. 제 8 항에 있어서,The method of claim 8,
    상기 (c) 단계에서 도포된 접착물질의 입자 크기는 1-500 ㎛인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The particle size of the adhesive material applied in the step (c) is 1-500 ㎛ manufacturing method of a secondary battery separator, characterized in that.
  12. 제 8 항에 있어서,The method of claim 8,
    상기 (c) 단계는 120-130 ℃ 온도와 100-300 kg·f/cm2의 압력에서 1-5 초 동안 압착하여 3층으로 적층된 분리막을 제조하는 것을 특징으로 하는 이차전지용 분리막의 제조방법.Step (c) is a method of manufacturing a separator for a secondary battery, characterized in that for producing a separator laminated in three layers by pressing for 1-5 seconds at a temperature of 120-130 ℃ temperature and 100-300 kg · f / cm 2 pressure .
  13. (d) 하기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계;(d) dissolving the compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution;
    (e) 상기 고분자 용액을 폴리올레핀 계열의 고분자 필름에 코팅하여, 하기 [화학식 1]로 표시되는 화합물이 코팅된 폴리올레핀 계열의 고분자 필름을 제조하는 단계;(e) coating the polymer solution on a polyolefin-based polymer film to prepare a polyolefin-based polymer film coated with a compound represented by the following [Formula 1];
    (f) 폴리올레핀 계열의 고분자 필름 위와 아래에 상기 [화학식 1]로 표시되는 화합물이 코팅된 고분자 필름을 위치시키고, 각 계면에 접착 물질을 도포한 후에 압착하여 3층으로 적층된 분리막을 제조하는 단계;를 포함하고,(f) placing a polymer film coated with the compound represented by the above [Formula 1] on and below the polyolefin-based polymer film, applying an adhesive material to each interface, and then compressing the same to prepare a separator laminated in three layers. Including;
    상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The polyolefin-based polymer is a method for producing a secondary battery separator, characterized in that the polyethylene or polypropylene.
    [화학식 1][Formula 1]
    Figure PCTKR2012008206-appb-I000009
    Figure PCTKR2012008206-appb-I000009
    상기 [화학식 1]에서,In [Formula 1],
    상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
  14. 제 13 항에 있어서,The method of claim 13,
    상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The adhesive material is a manufacturing method of a secondary battery separator, characterized in that the aqueous polymer solution diluted with vinyl ethylene acetate in water.
  15. 제 13 항에 있어서,The method of claim 13,
    상기 (d) 단계에서 용매는 클로로포름인 것을 특징으로 하는 이차전지용 분리막의 제조방법.In the step (d), the solvent is a method of manufacturing a secondary battery separator, characterized in that the chloroform.
  16. 제 13 항에 있어서,The method of claim 13,
    상기 (e) 단계는 상기 고분자 용액을 폴리올레핀 계열의 고분자 필름에 코팅시 딥-코팅 방법을 사용하고, 상기 딥-코팅의 속도는 8-9 mm/분인 것을 특징으로 하는 이차전지용 분리막의 제조방법.In the step (e), the dip-coating method is used when the polymer solution is coated on a polyolefin-based polymer film, and the dip-coating speed is 8-9 mm / min.
  17. 제 13 항에 있어서,The method of claim 13,
    상기 (f) 단계에서 도포된 접착물질의 입자 크기는 1-500 ㎛인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The particle size of the adhesive material applied in the step (f) is 1-500 ㎛ manufacturing method of a secondary battery separator, characterized in that.
  18. 제 13 항에 있어서,The method of claim 13,
    상기 (f) 단계는 120-130 ℃ 온도와 100-300 kg·f/cm2의 압력에서 1-5 초 동안 압착하여 3층으로 적층된 분리막을 제조하는 것을 특징으로 하는 이차전지용 분리막의 제조방법.Step (f) is a method of manufacturing a separator for a secondary battery, characterized in that to produce a separator laminated in three layers by pressing for 1-5 seconds at a temperature of 120-130 ℃ and 100-300 kg · f / cm 2 pressure .
  19. (g) 하기 [화학식 1]로 표시되는 화합물을 용매에 용해하고 교반하여 고분자 용액을 제조하는 단계; 및(g) dissolving the compound represented by the following [Formula 1] in a solvent and stirring to prepare a polymer solution; And
    (h) 3층으로 적층된 폴리올레핀 계열의 고분자 분리막의 표면을 하기 [화학식 1]로 표시되는 화합물로 코팅하는 단계;를 포함하고,(h) coating a surface of a polyolefin-based polymer separator laminated in three layers with a compound represented by the following [Formula 1]; and
    상기 3층으로 적층된 폴리올레핀 계열의 고분자 분리막은 제1층; 제2층; 및 상기 제1층과 제2층 사이에 존재하는 제3층;으로 이루어져 있으며, 제3층의 위와 아래에 제1층과 제2층을 위치시키고, 각 계면에 접착물질을 도포한 후에 압착하여 제조하고,The polyolefin-based polymer separator laminated in three layers comprises a first layer; Second layer; And a third layer existing between the first layer and the second layer. The first layer and the second layer are positioned above and below the third layer, and the adhesive material is applied to each interface and then compressed. Manufacturing,
    상기 폴리올레핀 계열의 고분자는 폴리에틸렌 또는 폴리프로필렌인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The polyolefin-based polymer is a method for producing a secondary battery separator, characterized in that the polyethylene or polypropylene.
    [화학식 1][Formula 1]
    Figure PCTKR2012008206-appb-I000010
    Figure PCTKR2012008206-appb-I000010
    상기 [화학식 1]에서,In [Formula 1],
    상기 r은 0<r<1이며, 상기 n은 1 내지 5000 사이의 정수이다.R is 0 <r <1, and n is an integer between 1 and 5000.
  20. 제 19 항에 있어서,The method of claim 19,
    상기 제1층 및 제2층은 폴리프로필렌 고분자층이고, 제3층은 폴리에틸렌 고분자층인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The first layer and the second layer is a polypropylene polymer layer, the third layer is a manufacturing method of a secondary battery separator, characterized in that the polyethylene polymer layer.
  21. 제 19 항에 있어서,The method of claim 19,
    상기 접착물질은 비닐에틸렌아세테이트를 물에 희석한 고분자 수용액인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The adhesive material is a manufacturing method of a secondary battery separator, characterized in that the aqueous polymer solution diluted with vinyl ethylene acetate in water.
  22. 제 19 항에 있어서,The method of claim 19,
    상기 (g) 단계에서 용매는 클로로포름인 것을 특징으로 하는 이차전지용 분리막의 제조방법.In the step (g), the solvent is a method of manufacturing a separator for a secondary battery, characterized in that chloroform.
  23. 제 19 항에 있어서,The method of claim 19,
    상기 (h) 단계는 상기 고분자 용액을 3층으로 적층된 폴리올레핀 계열의 고분자 분리막의 표면에 코팅시 딥-코팅 방법을 사용하고, 상기 딥-코팅의 속도는 8-9 mm/분인 것을 특징으로 하는 이차전지용 분리막의 제조방법.In the step (h), the dip-coating method is used when the polymer solution is coated on the surface of the polyolefin-based polymer separator laminated in three layers, and the speed of the dip-coating is 8-9 mm / min. Method of manufacturing a separator for secondary batteries.
  24. 제 19 항에 있어서,The method of claim 19,
    상기 3층으로 적층된 폴리올레핀 계열의 고분자 분리막의 각 계면에 도포된 접착물질의 입자 크기는 1-500 ㎛인 것을 특징으로 하는 이차전지용 분리막의 제조방법.The particle size of the adhesive material applied to each interface of the polyolefin-based polymer membrane laminated in three layers is 1-500 ㎛ characterized in that the manufacturing method of the secondary battery separator.
  25. 제 19 항에 있어서,The method of claim 19,
    상기 3층으로 적층된 폴리올레핀 계열의 고분자 분리막은 120-130 ℃ 온도와 100-300 kg·f/cm2의 압력에서 1-5 초 동안 압착하여 제조하는 것을 특징으로 하는 이차전지용 분리막의 제조방법.The polyolefin-based polymer separator laminated in three layers is prepared by pressing for 1-5 seconds at a temperature of 120-130 ℃ temperature and pressure of 100-300 kg · f / cm 2 for the secondary battery separator.
PCT/KR2012/008206 2011-10-27 2012-10-10 Multilayered separator for lithium secondary battery using functional polymer, and preparation method thereof WO2013062251A1 (en)

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KR20070082402A (en) * 2006-02-16 2007-08-21 주식회사 엘지화학 Organic/inorganic composite porous film and electrochemical device prepared thereby
KR20090094473A (en) * 2007-01-30 2009-09-07 아사히 가세이 이-매터리얼즈 가부시키가이샤 Multilayer porous membrane and method for producing the same
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KR20030032863A (en) * 2001-10-17 2003-04-26 엔이씨 도낀 가부시끼가이샤 Electrolytic Solution and Electrochemical Cell Using the Same
KR20070082402A (en) * 2006-02-16 2007-08-21 주식회사 엘지화학 Organic/inorganic composite porous film and electrochemical device prepared thereby
KR20090094473A (en) * 2007-01-30 2009-09-07 아사히 가세이 이-매터리얼즈 가부시키가이샤 Multilayer porous membrane and method for producing the same
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