WO2019190128A1 - Method of manufacturing pouch-type secondary battery - Google Patents

Method of manufacturing pouch-type secondary battery Download PDF

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Publication number
WO2019190128A1
WO2019190128A1 PCT/KR2019/003403 KR2019003403W WO2019190128A1 WO 2019190128 A1 WO2019190128 A1 WO 2019190128A1 KR 2019003403 W KR2019003403 W KR 2019003403W WO 2019190128 A1 WO2019190128 A1 WO 2019190128A1
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WO
WIPO (PCT)
Prior art keywords
secondary battery
pouch
type secondary
polymer electrolyte
pouch type
Prior art date
Application number
PCT/KR2019/003403
Other languages
French (fr)
Korean (ko)
Inventor
신원경
이재원
안경호
이철행
Original Assignee
주식회사 엘지화학
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020190032175A external-priority patent/KR102255539B1/en
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to EP19774534.2A priority Critical patent/EP3699993A4/en
Priority to US16/766,324 priority patent/US11114698B2/en
Priority to CN201980005669.0A priority patent/CN111344889A/en
Publication of WO2019190128A1 publication Critical patent/WO2019190128A1/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
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/102—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure
    • H01M50/105—Pouches or flexible bags
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to a method of manufacturing a pouch type secondary battery with improved electrolyte impregnation.
  • the lithium secondary battery may be classified into a square lithium secondary battery and a pouch type lithium secondary battery according to its shape.
  • the rectangular lithium secondary battery has a fixed shape, the design is limited, and in view of safety, the effect of venting gas or liquid is not smooth, and heat and gas accumulate inside the battery, so there is a high risk of explosion. have.
  • the pouch-type lithium secondary battery has no advantages in shape and size, easy to assemble through heat fusion, and has the advantage of high safety because it is easy to export the gas or liquid when abnormal behavior occurs.
  • the pouch-type lithium secondary battery is manufactured by inserting an electrode assembly having a porous separator between a positive electrode and a negative electrode in a pouch-shaped case of a predetermined size and shape, and then injecting and impregnating an electrolyte containing lithium salt.
  • the electrolyte is impregnated as it penetrates between the positive electrode, the negative electrode, and the separator by capillary force, and the electrode constituting the electrode assembly must be rapidly and completely impregnated with the electrolyte to optimize the cell performance.
  • the positive electrode, the negative electrode and the separator are all hydrophobic materials, since the electrolyte is a hydrophilic material, considerable time and demanding process conditions are required for the electrolyte to be sufficiently impregnated in the electrode assembly.
  • the present invention is to provide a method of manufacturing a pouch type secondary battery with improved impregnation of the composition for the gel polymer electrolyte to the electrode assembly.
  • Degassing comprising;
  • the ultrasonic member maintains a temperature of 30 °C to 80 °C
  • Pressing the pouch-type preliminary secondary battery provides a method of manufacturing a pouch-type secondary battery that is performed while applying a pressure of 0.1 Kgf / cm 2 to 3,000 kgf / cm 2 per area of the pouch-type preliminary secondary battery.
  • the ultrasonic member used in the method of the present invention may be made of a metal material selected from the group consisting of stainless steel, iron, aluminum, copper, nickel and two or more alloys thereof, and specifically, may be made of stainless steel or aluminum.
  • the ultrasonic member may be formed in a structure surrounding the front surface of the pouch type secondary battery.
  • the ultrasonic member may maintain a temperature of 30 °C to 60 °C.
  • the step of pressurizing the pouch type preliminary secondary battery may be a pressure of 0.1 Kgf / cm 2 to 500 kgf / cm 2, specifically 0.1 Kgf / cm 2 to 100 kgf / cm 2 per pouch type secondary battery. You can do it while.
  • the step of applying the ultrasonic vibration in the method of the present invention can be carried out by applying a vibration having a frequency of 20kHz to 200MHz.
  • the step of applying the ultrasonic vibration may be performed simultaneously with the step of injecting the gel polymer electrolyte composition.
  • the method of the present invention may further comprise the step of applying an ultrasonic vibration after the step of forming and before the step of curing the composition for gel polymer electrolyte.
  • the gel polymer electrolyte composition is effectively dispersed by applying pressure at a temperature of 30 ° C. or more using an ultrasonic member made of a metal material or by applying ultrasonic vibrations at the time of injection or after injection of the gel polymer electrolyte composition. Not only can the impregnation of the composition for electrolyte be improved, but also the wetting time can be shortened. As a result, a pouch type secondary battery having an improved initial capacity and a lower initial resistance can be manufactured.
  • FIG. 1 is a cross-sectional view of a pouch type secondary battery in which an ultrasonic member is disposed in a method of manufacturing a pouch type secondary battery according to an exemplary embodiment of the present invention.
  • Degassing comprising;
  • the ultrasonic member maintains a temperature of 30 °C to 80 °C
  • Pressing the pouch type preliminary secondary battery may be performed while applying a pressure of 0.1 Kgf / cm 2 to 3,000 kgf / cm 2 per area of the pouch type secondary battery.
  • the pouch type preliminary secondary battery of the present invention includes an electrode assembly and a pouch type case in which the electrode assembly is accommodated, and may be manufactured according to a conventional method known in the art.
  • the positive electrode, the separator, and the negative electrode may be sequentially stacked to form an electrode assembly, and then may be housed in a pouch-type (battery) case.
  • the electrode assembly is accommodated in the inner space, and then the remaining three corners except for one corner into which the gel polymer electrolyte composition is injected are first pouch-shaped.
  • a spare secondary battery can be manufactured.
  • the electrode assembly may be sequentially stacked in a state in which the separator is interposed between the positive electrode and the negative electrode and insulated from each other, and may be formed in various structures such as a winding type, a stack type, or a stack / fold type according to an embodiment. Can be.
  • the positive electrode may be manufactured by forming a positive electrode mixture layer on the positive electrode current collector.
  • the cathode mixture layer may be formed by coating a cathode slurry including a cathode active material, a binder, a conductive material, a solvent, and the like on a cathode current collector, followed by drying and rolling.
  • the positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes in the battery.
  • the positive electrode current collector may be formed of stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel. Surface treated with nickel, titanium, silver, or the like may be used.
  • the cathode active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically, may include a lithium metal oxide including lithium and one or more metals such as cobalt, manganese, nickel, or aluminum. Can be.
  • the lithium metal oxide may be lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O 4, etc.), lithium-cobalt oxide (eg, LiCoO 2, etc.), lithium-nickel oxide (for example, LiNiO 2, etc., lithium-nickel-manganese oxides (eg, LiNi 1-Y Mn Y O 2 (here, 0 ⁇ Y ⁇ 1), LiMn 2-z Ni z O 4 (here 0 ⁇ Z ⁇ 2) and the like, lithium-nickel-cobalt-based oxide (for example, LiNi 1-Y1 Co Y1 O 2 (here, 0 ⁇ Y1 ⁇ 1) and the like), lithium-manganese-cobalt-based Oxides (e.g., LiCo 1-Y2 Mn Y2 O 2 (here, 0 ⁇ Y2 ⁇ 1), LiMn 2-z1 Co z1 O 4 (here, 0 ⁇ Z1 ⁇ 2), etc.
  • the binder is a component that assists in bonding the active material, the conductive material, and the like to the current collector, and may generally be added in an amount of 1 to 30 wt% based on the total weight of solids in the positive electrode slurry.
  • binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro Low ethylene, polyethylene, polypropylene, ethylene-propylene-diene monomers, sulfonated ethylene-propylene-diene monomers, styrene-butadiene rubbers, fluororubbers, various copolymers, and the like.
  • the conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be added in an amount of 1 to 20 wt% based on the total weight of solids in the positive electrode slurry.
  • Such conductive materials include, for example, carbon powders such as carbon black, acetylene black (or denka black), Ketjen black, channel black, furnace black, lamp black, or thermal black; Graphite powders such as natural graphite, artificial graphite, or graphite with very advanced crystal structure; Conductive fibers such as carbon fibers and metal fibers; Conductive powders, such as carbon fluoride powder, aluminum powder, and nickel powder, etc. can be used.
  • the solvent may include an organic solvent such as N-methyl-2-pyrrolidone (NMP), and may be used in an amount that becomes a desirable viscosity when including the positive electrode active material and optionally a binder and a conductive material.
  • NMP N-methyl-2-pyrrolidone
  • the concentration of the solids in the slurry including the positive electrode active material and optionally the binder and the conductive material may be 10 wt% to 60 wt%, preferably 20 wt% to 50 wt%.
  • the positive electrode may include a positive electrode current collector region, that is, a positive electrode non-coating portion, in which the positive electrode active material layer is not formed, and the positive electrode is bonded to a positive electrode tab formed of a metal material such as aluminum (Al) at one end of the non-coating portion.
  • a positive electrode current collector region that is, a positive electrode non-coating portion, in which the positive electrode active material layer is not formed, and the positive electrode is bonded to a positive electrode tab formed of a metal material such as aluminum (Al) at one end of the non-coating portion.
  • Al aluminum
  • the negative electrode may be prepared by forming a negative electrode mixture layer on the negative electrode current collector.
  • the negative electrode mixture layer may be formed by coating a negative electrode slurry including a negative electrode active material, a binder, a conductive material, a solvent, and the like on a negative electrode current collector, followed by drying and rolling.
  • the negative electrode current collector generally has a thickness of 3 to 500 ⁇ m.
  • Such a negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery.
  • copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver, and the like on the surface, aluminum-cadmium alloy and the like can be used.
  • the negative electrode active material is a lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals with lithium, a material capable of doping and undoping lithium, and a transition It may include at least one selected from the group consisting of metal oxides.
  • any carbon-based negative electrode active material generally used in a lithium ion secondary battery may be used without particular limitation. Examples thereof include crystalline carbon, Amorphous carbons or these may be used together.
  • the metals or alloys of these metals with lithium include Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al And a metal selected from the group consisting of Sn or an alloy of these metals with lithium may be used.
  • Examples of the material capable of doping and undoping lithium include Si, SiO x (0 ⁇ x ⁇ 2), Sn, or SnO 2 , and may be used by mixing at least one of these with SiO 2 .
  • transition metal oxide examples include lithium-containing titanium oxide (LTO), vanadium oxide, lithium vanadium oxide, and the like.
  • the binder and the conductive material may be the same or different materials as the binder and the conductive material used in the positive electrode mixture layer as described above.
  • the solvent may include an organic solvent such as water or NMP, alcohol, etc., and may be used in an amount that becomes a desirable viscosity when including the negative electrode active material and optionally a binder and a conductive material.
  • concentration of the solids in the slurry including the negative electrode active material and, optionally, the binder and the conductive material may be 50 wt% to 75 wt%, preferably 50 wt% to 65 wt%.
  • the negative electrode may have a negative electrode current collector region, ie, a negative electrode non-coating portion, in which negative electrode active material layers are not formed at both sides.
  • the negative electrode may be bonded to a negative electrode tab formed of a metal material, such as nickel (Ni), at one end thereof.
  • Each of the positive electrode tab and the negative electrode tab extends from the electrode assembly, and each of the tabs may be partially or entirely connected to the positive electrode lead negative electrode lead, respectively, for electrical connection with an external terminal or device.
  • the positive lead and the negative lead are electrically connected to the electrode tabs by welding, and a part thereof may be exposed to the outside of the battery case.
  • the positive lead and the negative lead may be located in opposite directions in the battery case, or may be located side by side in the same direction.
  • the separator is positioned between the positive electrode and the negative electrode to electrically insulate the positive electrode and the negative electrode from each other, and may be formed in the form of a porous membrane to allow lithium ions to pass between the positive electrode and the negative electrode.
  • a separator may be made of, for example, a porous membrane using polyethylene (PE) or polypropylene (PP) or a composite film thereof.
  • the ultrasonic member of the metal material surrounding the front surface of the pouch type preliminary secondary battery may be disposed on both sides of the pouch type preliminary secondary battery manufactured as described above.
  • FIG. 1 is a cross-sectional view of a pouch-type preliminary secondary battery 100 in which an ultrasonic member is disposed in close contact with a method of manufacturing a pouch-type secondary battery according to an embodiment of the present invention.
  • the method of the present invention may be disposed in close contact with the ultrasonic member surrounding the front surface of the pouch-type secondary battery 100 on both sides of the pouch-type secondary battery 100, the electrode assembly accommodated.
  • the ultrasonic member may be a pair of ultrasonic members including the first ultrasonic member 110-1 and the second ultrasonic member 110-2 independently separated as shown in FIG. 1, or the first ultrasonic member. It may be an integrated ultrasonic member in which at least one surface of the ultrasonic member and the second ultrasonic member are coupled.
  • the ultrasonic member is preferably in contact with the side surface of the case of the pouch type preliminary secondary battery to facilitate the transmission of ultrasonic vibration, instead of using the adhesive member.
  • the ultrasonic member is preferably made of a metal material to facilitate temperature control and pressure control.
  • the metal material may include at least one metal selected from the group consisting of stainless steel, iron, aluminum, copper, nickel and two or more alloys thereof.
  • the ultrasonic member may be made of stainless steel or aluminum, more specifically aluminum in consideration of cost and heat transfer efficiency.
  • the ultrasonic member maintains a temperature of 30 ° C to 80 ° C, specifically 30 ° C to 60 ° C using a temperature control device (not shown) including a heating wire and the like coupled to a portion. It is preferable.
  • the ultrasonic member maintains the temperature range, it is possible to improve the impregnation effect during subsequent injection of the composition for the gel polymer electrolyte, and when ultrasonic vibration is applied, the temperature rises excessively in the pouch-type secondary battery, or internally by ultrasonic application. Desorption and damage of a substance such as an active material of an electrode can be prevented from occurring.
  • the viscosity of the gel polymer electrolyte composition may be increased during subsequent injection of the composition for gel polymer electrolyte, impregnation may be reduced, and if it exceeds 80 °C, the temperature rise inside the pouch type secondary battery This may cause damage due to chemical and physical side reactions between the composition for gel polymer electrolyte and the electrode or separator upon subsequent injection of the composition for gel polymer electrolyte, thereby causing an internal short circuit of the cell.
  • the electrode assembly after placing the ultrasonic member surrounding the front surface of the pouch-type preliminary secondary battery in close contact with both sides of the pouch-type preliminary secondary battery, the electrode assembly through one corner of the pouch-type case in an open state
  • the gel polymer electrolyte composition may be injected into the pouch-type case in which is stored.
  • the surface in which the injection hole of the composition for the gel polymer electrolyte is formed is adjacent to the surface of the sealing portion in which the negative electrode tab and the positive electrode tab, but is preferably a different surface.
  • the composition for gel polymer electrolyte used in the secondary battery manufacturing method of the present invention comprises (a) a lithium salt, (b) an organic solvent, (c) a polymerizable monomer, (d) a polymerization initiator and optionally (e) an additive. It can use to include.
  • the (a) lithium salt may be used without limitation those conventionally included in the gel polymer electrolyte, for example, include Li + as a cation, F ⁇ , Cl ⁇ , Br ⁇ , I ⁇ , NO 3 -, N (CN) 2 -, ClO 4 -, BF 4 -, B 10 Cl 10 -, PF 6 -, CF 3 SO 3 -, CH 3 CO 2 -, CF 3 CO 2 -, AsF 6 - , SbF 6 -, AlCl 4 - , AlO 4 -, CH 3 SO 3 -, BF 2 C 2 O 4 -, BC 4 O 8 -, PF 4 C 2 O 4 -, PF 2 C 4 O 8 -, ( CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, C 4 F 9 SO 3 -, CF 3 CF 2 SO
  • the lithium salt is LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , LiAlO 4 , LiCH 3 SO 3 , LiFSI (lithium fluorosulfonyl imide, LiN (SO 2 F) 2 ), LiTFSI (lithium (bis) trifluoromethanesulfonimide, LiN (SO 2 CF 3 ) 2 ) and LiBETI (lithium bisperfluoroethanesulfonimide, LiN (SO 2 C 2 F 5) may comprise a 2) danilmul or in combination of two or more thereof selected from the group consisting of.
  • the lithium salt may include a single substance or a mixture of two or more selected from the group consisting of LiBF 4 , LiPF 6 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiCH 3 SO 3 , LiFSI, LiTFSI, and LiBETI.
  • lithium salts commonly used in electrolytes for lithium secondary batteries can be used without limitation.
  • the lithium salt may be appropriately changed within a range generally available, but in order to obtain an effect of forming an anti-corrosion coating on the surface of the electrode, a concentration of 0.8 M to 4.0 M in the composition for gel polymer electrolyte, specifically 1.0 M to 3.0 It may be included in M concentration.
  • the concentration of the lithium salt is less than 0.8M, the effect of improving the low temperature output and the cycle characteristics of the lithium secondary battery during high temperature storage is insignificant, and when the concentration exceeds 4.0M, the gel polymer electrolyte increases as the viscosity of the gel polymer electrolyte composition increases. Impregnation of the composition may decrease.
  • the organic solvent (b) may be minimized as long as the organic solvent may be decomposed by an oxidation reaction or the like during the charging and discharging process of the secondary battery, and may be a non-aqueous organic solvent capable of exhibiting desired properties with an additive.
  • a carbonate solvent, an ether solvent, an ester solvent, etc. can be used individually or in mixture of 2 or more types, respectively.
  • Examples of the carbonate solvent in the organic solvent include a cyclic carbonate solvent or a linear carbonate solvent.
  • cyclic carbonate solvent examples include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate , 2,3-pentylene carbonate, vinylene carbonate, and fluoroethylene carbonate (FEC), any one selected from the group consisting of, or two or more solvents thereof.
  • the linear carbonate solvent is selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate Any one or two or more of these solvents can be mentioned.
  • the ether solvent may be any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, and ethyl propyl ether or two or more of them.
  • the ester solvent may include a linear ester solvent or a cyclic ester solvent, and examples of the linear ester solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl.
  • cyclic ester solvent examples include ⁇ -butyrolactone, ⁇ -valerolactone, ⁇ -caprolactone, ⁇ -valerolactone or ⁇ -caprolactone.
  • the (c) polymerizable monomer is a multifunctional acrylate compound containing at least one acrylate group in the molecule, and a multifunctional methacrylate containing at least one methacrylate group so as to polymerize with each other to form a polymer.
  • the polymerizable monomer may be a compound represented by the following formula (1).
  • a and A ' are each independently an acrylate group, a methacrylate group, an alkylene group having 1 to 10 carbon atoms containing at least one or more acrylate groups or methacrylate groups, or -OR 1 , wherein R 1 is An alkylene group having 1 to 10 carbon atoms or at least one or more acrylate groups or methacrylate groups, or -OR 2 -OR 3 , wherein R 2 and R 3 are each at least one acrylate group or methacrylate group; It is a C1-C10 alkylene group containing,
  • B is an oxyalkylene group.
  • a and A ' may each independently include at least one or more of the units represented by Formulas A-1 to A-5.
  • An acrylate group or methacrylate group positioned at the terminal of the polymerizable monomer may form a polymer network by a polymerization reaction with an organic binder including an ethylenically unsaturated group.
  • Such compounds can be derived from monomers comprising mono or polyfunctional acrylate groups or methacrylate groups.
  • the B may include a unit represented by the following formula (B-1).
  • R is an alkylene group having 1 to 10 carbon atoms
  • R 3 is O or an alkylene group having 1 to 5 carbon atoms
  • k1 is an integer of any one of 1 to 30,
  • n is an integer of any one of 0-3.
  • R may be each independently -CH 2 CH 2 -or -CH 2 CH 2 CH 2- .
  • Chemical Formula 1 More specifically, the compound represented by Chemical Formula 1 may be represented by the following Chemical Formula 1a.
  • the polymerizable monomer may be included in an amount of 0.5 wt% to 20 wt%, specifically 0.7 wt% to 15 wt%, and more specifically 1.0 wt% to 10 wt%, based on the total weight of the gel polymer electrolyte composition.
  • the content of the polymerizable monomer is 0.5% by weight or more, the effect of forming a gel reaction can be improved to secure sufficient mechanical strength of the gel polymer electrolyte, and when the content is 20% by weight or less, an increase in resistance according to the oligomer content and a lithium ion It is possible to avoid disadvantages such as the limitation of (limiting ion conductivity).
  • the polymerization initiator (d) may be used a conventional polymerization initiator known in the art.
  • the polymerization initiator may be used by selecting one or more selected from the group consisting of a UV polymerization initiator, a photo polymerization initiator, and a thermal polymerization initiator.
  • the UV polymerization initiator is a representative example of 2-hydroxy-2-methylpropiophenone, 1-hydroxy-cyclohexylphenyl-ketone, benzophenone, 2-hydroxy-1- [4- (2-hydroxy Oxyethoxy) phenyl] -2-methyl-1-propaneone, oxy-phenylacetic acid 2- [2-oxo-2 phenyl-acetoxy-ethoxy] -ethyl ester, oxy-phenyl-acetic 2- [2-hydroxyethoxy] -ethyl ester, alpha-dimethoxy-alpha-phenylacetophenone, 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl] -1 -Butanone, 2-methyl-1- [4- (methylthio) phenyl] -2- (4-morpholinyl) -1-propanone, diphenyl (2,4,6-trimethylbenzoyl) -phos
  • the photo or thermal polymerization initiator is a typical example of benzoyl peroxide, acetyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide.
  • the polymerization initiator is a compound which can be decomposed by UV or heat in a battery at 30 ° C. to 100 ° C. or decomposed by light at room temperature (5 ° C. to 30 ° C.) to form radicals. It can be used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polymer (A) to be displayed. When the polymerization initiator is included in 10 parts by weight or less, it is possible to control the polymerization rate in the polymer electrolyte, thereby preventing the disadvantage that the unreacted polymerization initiator remains and later adversely affects the battery performance. In addition, the polymerization initiator should be included 0.1 parts by weight or more to facilitate the polymerization reaction between the polymer (A) compound represented by the formula (1), a polymer electrolyte having a uniform thickness can be prepared.
  • the additive may be used without limitation those conventionally used in the gel polymer electrolyte, and representative examples thereof include vinylene carbonate (VC), propane sultone (PS), succinonitrile (SN), adiponitrile, Ethylene sulfite (ESa), 1,3-propane sultone (PRS), propylene ethylene carbonate (FEC), LiPO 2 F 2 , LiODFB, LiBOB, tetramethyl trimethyl silyl phosphate (TMSPa), trimethyl silyl phosphite (TMSPi), Lithium difluoro (bisoxalato) phosphate, lithium difluorophosphate, lithium oxalyldifluoroborate, tris (2,2,2-trifluoroethyl) phosphate (TFEPa) or tris (trifluoroethyl Phosphite (TFEPi) and the like.
  • VC vinylene carbonate
  • PS propane sultone
  • the opened sealing parts may be adhered to each other and sealed, followed by a subsequent step.
  • the gel polymer electrolyte composition injection port is sealed before the ultrasonic vibration is applied, so that the gel polymer electrolyte composition may be volatilized, or the inside of the battery may be prevented from occurring in the pouch-type case.
  • the sealing may be performed for 1 second to 10 seconds at 130 ° C. to 160 ° C., specifically for 2 seconds to 3 seconds at 140 ° C. to 150 ° C., so that the polymer layers of the pouch type case may be adhered to each other.
  • the step of applying the ultrasonic vibration may be performed by applying a vibration having a frequency of 20kHz to 200MHz, specifically 31kHz to 200MHz.
  • a vibration having a frequency of 20kHz to 200MHz specifically 31kHz to 200MHz.
  • 0.1 Kgf / cm2 to 3,000 kgf / cm2 pressure specifically 0.1 Kgf / cm2 to 500 kgf / cm2 pressure, more specifically 0.1 Kgf / per pouch type secondary battery by using the hydraulic press, etc. while applying the ultrasonic vibration
  • the pouch type secondary battery may be pressurized while applying a pressure of cm 2 to 100 kgf / cm 2, more specifically, 0.1 Kgf / cm 2 to 50 kgf / cm 2.
  • the dispersion effect of the composition for gel polymer electrolytes can be improved more.
  • the pressure when the pressure is applied to less than 0.1 Kgf / cm2 per area of the pouch type secondary battery, it may be difficult to transmit the ultrasonic vibration to the inside of the cell, when applying a pressure exceeding 3,000 kgf / cm2 per area of the pouch type secondary battery pouch type secondary Excessively high pressure may be applied to the cell causing cell damage.
  • the step of applying the ultrasonic vibration is a cycle having a rest for 5 seconds to 10 seconds after applying ultrasonic vibration for 5 seconds to 10 seconds, the cycle about 50 to 150 times, specifically about 100 times Can be repeated.
  • the ultrasonic member is formed to completely surround the front surface of the pouch-type preliminary secondary battery, it is possible to prevent the heat loss inside the pouch-type preliminary secondary battery and more stably maintain the cell temperature.
  • uniform pressure and ultrasonic vibration may be applied to the front surface of the pouch type preliminary secondary battery, and the working environment may be improved by reducing noise generated when ultrasonic vibration is applied.
  • the step of applying the ultrasonic vibration in the method of the present invention may be performed at the same time as the injection of the composition for the gel polymer electrolyte, or may be performed after the injection of the composition for the gel polymer electrolyte is completed, sealed.
  • the viscosity of the gel polymer electrolyte composition is lowered and the mobility of the molecules is improved to form an electrode plate and a separator constituting the electrode assembly. Since it is easier to impregnate, the impregnability (wetting) of the composition for gel polymer electrolyte can be greatly improved. Thus, after the injection of the gel polymer electrolyte composition, it is possible to shorten the wetting time and the manufacturing time of the pouch type secondary battery.
  • pre-gelling reactivity of the gel polymer electrolyte composition can be suppressed by injecting and sealing the gel polymer electrolyte composition and then applying ultrasonic vibration.
  • the pouch type secondary battery manufacturing method of the present invention when the ultrasonic vibration is applied, it is possible to control the heat generation temperature range inside the pouch type secondary battery caused by the ultrasonic vibration using the ultrasonic member.
  • the step of forming the pouch type secondary battery may be performed after the step of applying the ultrasonic vibration.
  • the formation step may be charged and discharged up to 1.7V to 4.4V at 100C to 200mA at 0.05C to 0.1C at 70 ° C or less, and specifically, may be performed to 0.05V at 0.05C.
  • the method of the present invention may further perform the aging step after the forming step.
  • the aging step is carried out within 1 hour to 72 hours (3 days) at room temperature of 25 °C to 60 °C, specifically 30 °C to 40 °C room temperature to prevent pregelation and sufficiently wet the electrode in the composition for gel polymer electrolyte can do.
  • the formation By carrying out the process and the aging process at 70 ° C. or less, a sufficient SEI film can be formed, and side reactions can be prevented by controlling the wetting property improving effect and the electrolyte salt decomposition reaction.
  • the method of the present invention may further perform a vacuum wetting step after the aging step to improve the wettability.
  • the vacuum wetting step is preferably exposed for a short period of time under a weaker vacuum pressure than the conventional wetting conditions. Specifically, the vacuum wetting step may be repeated three times while reducing the pressure for 10 to 20 seconds in a vacuum chamber. It may be repeated three times while reducing the pressure for 15 to 20 seconds.
  • a large amount of gas generated due to the side reaction of the gas resulting from the positive electrode active material and the composition for the positive electrode active material and the gel polymer electrolyte may occur. If the gas generated in the battery cell is not efficiently removed in the formation step, the gas occupies a certain space in the battery cell, thereby preventing the formation of uniformly, adversely affecting battery performance and battery life such as capacity and output. Get mad. In addition, there is a problem that the capacity of the battery decreases rapidly as the number of charge / discharge increases due to the gas remaining inside the battery cell, or the battery cell swells.
  • the method of the present invention may further include degassing the gas generated in the formation step by opening a portion of the case after the formation step.
  • the method may further comprise applying ultrasonic vibration after the degassing step.
  • the step of applying the ultrasonic vibration can be carried out under the same conditions as the step of applying the ultrasonic vibration described above.
  • the dispersibility of the composition for the gel polymer electrolyte is improved to increase the impregnation, thereby making it more uniform and stable.
  • the gel polymer electrolyte can be cured.
  • a step of curing (gelling) the gel polymer electrolyte composition may be performed after the formation step.
  • the curing (gelling) step may be carried out through a photocuring process by conventional heat, e-beam, gamma irradiation.
  • the curing (gelling) step may be carried out by thermal curing for 5 hours to 24 hours in a temperature range of 30 °C to 70 °C, specifically 40 °C to 65 °C under inert conditions (inert condition).
  • the inert atmosphere may be a gas having low reactivity known in the art, in particular one or more inert gases selected from the group consisting of nitrogen, argon, helium and xenon.
  • the polymerizable monomers may be crosslinked with each other to form a polymer network in a gel form, and electrolyte salts dissociated from the composition for gel polymer electrolyte may be uniformly impregnated in the polymer network.
  • the method of the present invention may further comprise the step of aging for 1 hour to 24 hours under the curing step, 25 °C to 70 °C, specifically 30 °C to 60 °C conditions.
  • an additional SEI film may be formed by leaving the battery, which has been charged and discharged and cured, at a room temperature for a period of time, thereby inducing additional gas generation.
  • the step of curing the gel polymer electrolyte composition it may be carried out a step of degassing.
  • the degassing step may be performed while applying pressure to the battery case.
  • the degassing step can be carried out at a pressure of -85 kPa to -95 kPa.
  • the opened area of the pouch type case may be sealed at a temperature of 120 ° C. to 150 ° C. for about 2 seconds to 5 seconds.
  • the ultrasonic member is placed in close contact with the pouch-type secondary battery during manufacture of the pouch-type secondary battery, and the gel polymer electrolyte composition is injected, or simultaneously with the gel polymer electrolyte composition injection.
  • the composition for gel polymer electrolyte can be effectively dispersed to improve the impregnation of the composition for gel polymer electrolyte.
  • LiCoO 2 as a positive electrode active material, carbon black as a conductive material, and PVDF as a binder were added to N-methyl-2-pyrrolidone (NMP) as a solvent in a 94: 3: 3 weight ratio to obtain a positive electrode mixture slurry (solid content). 65 wt%) was prepared.
  • the positive electrode mixture slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of about 20 ⁇ m, and dried, followed by roll press to prepare a positive electrode.
  • an electrode assembly was manufactured by winding and compressing a separator having a thickness of 20 ⁇ m between polyethylene electrodes, and inserting the same into a pouch-type battery case, thereby preparing a pouch-type secondary battery. .
  • an ultrasonic member made of aluminum (Al) covering the entire surface of the pouch type preliminary secondary battery was disposed on both surfaces of the pouch type preliminary secondary battery.
  • the prepared composition for gel polymer electrolyte was injected, and the composition injection hole for the gel polymer electrolyte was sealed at 140 ° C.
  • the formation process was performed for 3 hours at 200 mA at 0.1 C, then aged at room temperature for 2 days, and the curing process was performed at 65 ° C. for 5 hours to prepare a gel polymer electrolyte.
  • a degassing step was performed while applying a -85 kPa pressure to remove the gas generated therein, thereby manufacturing the pouch type secondary battery of the present invention.
  • composition for gel polymer electrolyte was inject
  • the ultrasonic member is used to pressurize a pressure of 10 Kgf / cm2 per area of the pouch type preliminary secondary battery, and apply 25 KHz of ultrasonic vibration for 100 cycles (1 cycle: 5 seconds of ultrasonic vibration / 5 seconds of rest). Then, a pouch type secondary battery was manufactured in the same manner as in Example 1.
  • the composition for gel polymer electrolyte is injected at room temperature (25 ° C.), the composition injection hole for the gel polymer electrolyte is sealed at 140 ° C., and then the formation process and the ultrasonic wave process are not performed.
  • a pouch type secondary battery was manufactured in the same manner as in Example 1, except that the curing step was performed.
  • the composition for gel polymer electrolyte was infused while maintaining the ultrasonic member temperature at 40 ° C., the composition injection hole for the gel polymer electrolyte was sealed at 140 ° C., and then the ultrasonic wave and the addition step were not performed.
  • a pouch type secondary battery was manufactured in the same manner as in Example 1, except that the formation step and the curing step were performed.
  • the composition for gel polymer electrolyte was inject
  • a pouch type secondary battery was manufactured in the same manner as in Example 1 except that an ultrasonic process was not performed using an ultrasonic member and a pressure of 5 Kgf / cm 2 per area was applied to the pouch type secondary battery.
  • a pouch type secondary battery was manufactured in the same manner as in Example 1 except that the ultrasonic member temperature was maintained at room temperature (25 ° C).
  • a pouch type secondary battery was manufactured in the same manner as in Example 2 except that the ultrasonic member temperature was maintained at room temperature (25 ° C).
  • the ultrasonic vibration at 20 KHz was performed 100 cycles (1 cycle: 5) without pressurization using the ultrasonic member.
  • Pouch-type secondary battery was manufactured in the same manner as in Example 1, except that the ultrasonic wave was subjected to ultrasonic vibration / 5 second rest period).
  • a pouch type secondary battery was manufactured in the same manner as in Example 1 except that the ultrasonic member temperature was maintained at 100 ° C.
  • the ultrasonic member temperature is maintained at room temperature (25 ° C.), except for pressurizing at a pressure of 3,500 Kgf / cm2 per area of the pouch type preliminary secondary battery using the ultrasonic member during pressurization.
  • a pouch type secondary battery was manufactured in the same manner as in 1.
  • Impregnation of the pouch-type secondary battery including the gel polymer electrolytes prepared in Example 1 and Comparative Example 1 was measured using AC impedance measurement at 25 ° C. At this time, the ion conductivity was measured in the frequency band 0.05Hz to 100MHz using VMP3 measuring equipment and 4294A. The results are shown in FIG. 2. 2, the horizontal axis represents a real value Z re of the impedance Z calculated by the impedance calculator, and the vertical axis represents an imaginary value Z im of impedance.
  • the reference example in Figure 2 shows the AC impedance measured immediately after the injection of the composition for the gel polymer electrolyte in Example 1.
  • the resistance decreases because the composition for the gel polymer electrolyte is less impregnated with the pore inside the battery. Therefore, when the AC impedance is measured, the bulk resistance is measured to be small, and the resistance value converges as the impregnation proceeds.
  • the pouch type secondary battery of Comparative Example 1 in which the pouch type secondary battery of Example 1, which performed the step of applying ultrasonic vibration based on the value of the pouch type secondary battery of the reference example, was not subjected to the step of applying the ultrasonic vibration. It can be seen that the bulk resistance value is significantly reduced than the battery.
  • the rate of 0.3 C in the constant current-constant voltage (CC-CV) method At a current of 333mA to charge a constant current (CC) until the battery's voltage reaches 4.2V, and after the battery's voltage reaches 4.2V, it cuts off at a current of 0.05C while maintaining the constant voltage (CV) of 4.2V. -off) and charged once.
  • the first charged battery was repeated three times in one cycle of constant current (CC) discharge at a constant current of 333 mA at a rate of 0.3 C until the battery voltage reached 3 V, and the third discharge capacity was selected as the initial capacity. It was.
  • Table 2 The results are shown in Table 2 below.
  • the rate of 0.3 C in the constant current-constant voltage (CC-CV) method At a current of 333mA to charge a constant current (CC) until the battery's voltage reaches 4.2V, and after the battery's voltage reaches 4.2V, it cuts off at a current of 0.05C while maintaining the constant voltage (CV) of 4.2V. -off) and charged once.
  • the first charged battery was repeated three times in a cycle of performing constant current (CC) discharge at a constant current of 333 mA at a rate of 0.3 C until the battery voltage reached 3 V, and a current of 2 A (2 C) was 10 times.

Abstract

The present invention relates to a method of producing a pouch-type secondary battery. More specifically, the present invention relates to a method of producing a pouch-type secondary battery, the method comprising: a step of placing an electrode assembly in an inner space of a pouch-type case to produce a preliminary pouch-type electrode; a step of placing an ultrasonic member of metal material against both sides of a preliminary pouch-type secondary battery; a step of injecting a gel-polymer electrolyte composition into the preliminary pouch-type secondary battery; a step of pressing the preliminary pouch-type secondary battery by using the ultrasonic member and applying ultrasonic vibrations to the preliminary pouch-type secondary battery; a step of forming the preliminary pouch-type secondary battery; a step of curing the gel-polymer electrolyte composition; and a step of degassing, wherein the ultrasonic member is maintained at a temperature of 30-80℃ and the step of pressing the preliminary pouch-type secondary battery is carried out while applying a pressure of 0.1-3,000 kgf/㎠ per unit area of the preliminary pouch-type secondary battery.

Description

파우치형 이차전지의 제조 방법Manufacturing method of pouch type secondary battery
관련 출원(들)과의 상호 인용Cross Citation with Related Application (s)
본 출원은 2018년 03월 26일자 한국 특허 출원 제2018-0034688호 및 2019년 03월 21일자 한국 특허 출원 제2019-0032175호에 기초한 우선권의 이익을 주장하며, 해당 한국 특허 출원의 문헌에 개시된 모든 내용은 본 명세서의 일부로서 포함된다.This application claims the benefit of priority based on Korean Patent Application No. 2018-0034688 dated March 26, 2018 and Korean Patent Application No. 2019-0032175 dated March 21, 2019, and all disclosed in the literature of the Korean patent application. The contents are included as part of this specification.
기술분야Field of technology
본 발명은 전해질 함침성이 향상된 파우치형 이차전지의 제조 방법에 관한 것이다.The present invention relates to a method of manufacturing a pouch type secondary battery with improved electrolyte impregnation.
모바일 기기에 대한 기술 개발과 수요가 증가함에 따라 에너지원으로서의 이차전지에 대해 수요가 급격히 증가하고 있고, 그러한 이차전지 중에서도 높은 에너지 밀도와 작동 전위를 나타내고, 사이클 수명이 길며, 자기방전율이 낮은 리튬 이차전지가 상용화되어 널리 사용되고 있다.As the development and demand for mobile devices increases, the demand for secondary batteries as energy sources is increasing rapidly. Among them, lithium secondary batteries with high energy density and operating potential, long cycle life, and low self discharge rate Batteries have been commercialized and widely used.
리튬 이차전지는 형상에 따라 각형 리튬 이차전지와 파우치형 리튬 이차전지로 나눌 수 있다.The lithium secondary battery may be classified into a square lithium secondary battery and a pouch type lithium secondary battery according to its shape.
상기 각형 리튬 이차전지는 형태가 고정되어 있어 디자인이 한정되고, 안전성 측면에서 기체 또는 액체를 내보내는 효과 (vent)가 원활하지 못하기 때문에 전지 내부에 열 및 가스가 축적되어 폭발의 위험성이 크다는 단점이 있다.Since the rectangular lithium secondary battery has a fixed shape, the design is limited, and in view of safety, the effect of venting gas or liquid is not smooth, and heat and gas accumulate inside the battery, so there is a high risk of explosion. have.
반면에, 상기 파우치형 리튬 이차전지는 형태 및 크기에 제약이 없고, 열융착을 통한 조립이 쉬우며, 이상거동 발생 시 기체나 액체를 내보내는 효과가 용이하여 안전성이 높다는 장점이 있다.On the other hand, the pouch-type lithium secondary battery has no advantages in shape and size, easy to assemble through heat fusion, and has the advantage of high safety because it is easy to export the gas or liquid when abnormal behavior occurs.
이러한 파우치형 리튬 이차전지는 양극과 음극 사이에 다공성 세퍼레이터가 개재된 전극조립체를 일정 크기 및 모양의 파우치형 케이스에 삽입한 후, 리튬염을 포함하는 전해질을 주액하여 함침하는 방법으로 제조된다.The pouch-type lithium secondary battery is manufactured by inserting an electrode assembly having a porous separator between a positive electrode and a negative electrode in a pouch-shaped case of a predetermined size and shape, and then injecting and impregnating an electrolyte containing lithium salt.
전해질은 모세관 힘(capillary force)에 의해 양극, 음극 및 세퍼레이터 사이로 스며들어 가면서 함침되는데, 상기 전극조립체를 구성하는 전극이 전해질에 의해 신속하고 완전하게 함침되어야 전지 성능을 최적화할 수 있다.The electrolyte is impregnated as it penetrates between the positive electrode, the negative electrode, and the separator by capillary force, and the electrode constituting the electrode assembly must be rapidly and completely impregnated with the electrolyte to optimize the cell performance.
그러나 재료의 특성상, 양극, 음극 및 세퍼레이터 모두 소수성이 큰 물질인 반면, 전해질은 친수성 물질이기 때문에, 전극조립체 내에 전해질이 충분히 함침되는데 상당한 시간 및 까다로운 공정 조건이 요구된다. However, due to the nature of the material, since the positive electrode, the negative electrode and the separator are all hydrophobic materials, since the electrolyte is a hydrophilic material, considerable time and demanding process conditions are required for the electrolyte to be sufficiently impregnated in the electrode assembly.
더욱이, 이차전지와 같은 디바이스가 점차 대형화되어 감에 따라, 전해질이 침투할 수 있는 부피는 감소하는 반면에, 침투 면적이 넓어져서 전해질이 전극조립체 내부까지 함침되지 못하고 외부에 국부적으로만 존재할 가능성이 커졌다. 그 결과, 이차전지 내부에서 불균일한 전해질 분포로 이차전지 용량 및 성능이 크게 감소하는 문제가 대두되고 있다. Moreover, as devices such as secondary batteries become larger in size, the volume of electrolyte penetration can decrease, while the penetration area becomes wider, so that the electrolyte can only exist locally outside without being impregnated into the electrode assembly. Got bigger. As a result, a problem that the secondary battery capacity and performance is greatly reduced due to non-uniform electrolyte distribution inside the secondary battery.
더욱이, 최근에는 안전성 등을 확보하기 위하여 겔 폴리머 전해질을 포함하는 리튬 이차전지가 상용화 되면서, 점도가 상대적으로 높은 겔 폴리머 전해질용 조성물의 사용이 증가하고 있다.Moreover, in recent years, as lithium secondary batteries including gel polymer electrolytes are commercialized to secure safety, use of gel polymer electrolyte compositions having a relatively high viscosity is increasing.
이에, 겔 폴리머 전해질용 조성물의 함침성(wetting)을 향상시키기 위한 방법이 요구되고 있다.Accordingly, there is a need for a method for improving the wetting of the composition for gel polymer electrolytes.
종래 함침성 개선을 위해 높은 온도에서 겔 폴리머 전해질용 조성물을 주액하거나, 또는 감압 상태에서 겔 폴리머 전해질용 조성물을 주액하는 방법 등이 제안되었다. 하지만, 이 경우 기존의 전극조립체 내부로 겔 폴리머 전해질용 조성물이 함침되기 전에 프리겔(pre-gel)화가 야기되거나, 또는 주액된 겔 폴리머 전해질용 조성물이 열이나 압력에 의해 변형되면서, 내부 단락과 같은 또 다른 문제를 야기한다.In order to improve impregnation, a method of injecting a composition for gel polymer electrolyte at a high temperature or injecting a composition for gel polymer electrolyte at a reduced pressure has been proposed. In this case, however, pre-gelation occurs before the gel polymer electrolyte composition is impregnated into the existing electrode assembly, or the injected gel polymer electrolyte composition is deformed by heat or pressure. It causes the same another problem.
이에, 겔 폴리머 전해질용 조성물의 변형 없이 전해질의 함침성을 향상시킬 수 있는 파우치형 이차전지의 제조방법에 대한 기술이 필요한 실정이다.Accordingly, there is a need for a technique for manufacturing a pouch type secondary battery capable of improving the impregnation of an electrolyte without modifying the gel polymer electrolyte composition.
선행기술문헌: 한국 특허공개공보 제2014-0059746호Prior Art Document: Korean Patent Publication No. 2014-0059746
본 발명에서는 전극 조립체에 대한 겔 폴리머 전해질용 조성물의 함침성이 향상된 파우치형 이차전지의 제조 방법을 제공하고자 한다.The present invention is to provide a method of manufacturing a pouch type secondary battery with improved impregnation of the composition for the gel polymer electrolyte to the electrode assembly.
본 발명의 일 실시예에서는In one embodiment of the present invention
파우치형 케이스의 내부 공간에 전극조립체를 수납하여 파우치형 예비(preliminary) 전지를 제조하는 단계;Manufacturing a pouch type preliminary battery by accommodating an electrode assembly in an inner space of the pouch type case;
파우치형 예비 이차전지의 양면에 금속 소재의 초음파 부재를 밀착하여 배치하는 단계;Disposing the ultrasonic member made of a metal material on both sides of the pouch type secondary battery;
상기 파우치형 예비 이차전지 내부에 겔 폴리머 전해질용 조성물을 주입하는 단계;Injecting a gel polymer electrolyte composition into the pouch-type preliminary secondary battery;
상기 초음파 부재를 이용하여 상기 파우치형 예비 이차전지를 가압하면서 파우치형 예비 이차전지에 초음파 진동을 가해주는 단계;Applying ultrasonic vibration to the pouch type secondary battery while pressurizing the pouch type secondary battery using the ultrasonic member;
상기 파우치형 예비 이차전지를 포메이션하는 단계;Forming the pouch type secondary battery;
상기 겔 폴리머 전해질용 조성물을 경화하는 단계; 및Curing the gel polymer electrolyte composition; And
탈기하는 단계;를 포함하며,Degassing; comprising;
상기 초음파 부재는 30℃ 내지 80℃의 온도를 유지하고,The ultrasonic member maintains a temperature of 30 ℃ to 80 ℃,
상기 파우치형 예비 이차전지를 가압하는 단계는 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 내지 3,000 kgf/㎠ 압력을 가하면서 실시하는 것인 파우치형 이차전지의 제조방법을 제공한다.Pressing the pouch-type preliminary secondary battery provides a method of manufacturing a pouch-type secondary battery that is performed while applying a pressure of 0.1 Kgf / cm 2 to 3,000 kgf / cm 2 per area of the pouch-type preliminary secondary battery.
본 발명의 방법에서 사용되는 상기 초음파 부재는 스테인레스, 철, 알루미늄, 구리, 니켈 및 이들의 2종 이상의 합금으로 이루어진 군으로부터 선택된 금속 소재로 이루어질 수 있으며, 구체적으로 스테인리스 또는 알루미늄으로 이루어질 수 있다.The ultrasonic member used in the method of the present invention may be made of a metal material selected from the group consisting of stainless steel, iron, aluminum, copper, nickel and two or more alloys thereof, and specifically, may be made of stainless steel or aluminum.
또한, 상기 초음파 부재는 파우치형 예비 이차전지의 전면을 감싸는 구조로 형성될 수 있다.In addition, the ultrasonic member may be formed in a structure surrounding the front surface of the pouch type secondary battery.
또한, 본 발명의 방법에서, 상기 초음파 부재는 30℃ 내지 60℃의 온도를 유지할 수 있다.In addition, in the method of the present invention, the ultrasonic member may maintain a temperature of 30 ℃ to 60 ℃.
또한, 본 발명의 방법에서, 상기 파우치형 예비 이차전지를 가압하는 단계는 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 내지 500 kgf/㎠ 압력, 구체적으로 0.1 Kgf/㎠ 내지 100 kgf/㎠ 압력을 가하면서 실시할 수 있다.Further, in the method of the present invention, the step of pressurizing the pouch type preliminary secondary battery may be a pressure of 0.1 Kgf / cm 2 to 500 kgf / cm 2, specifically 0.1 Kgf / cm 2 to 100 kgf / cm 2 per pouch type secondary battery. You can do it while.
또한, 본 발명의 방법에서 상기 초음파 진동을 가해주는 단계는 20kHz 내지 200 MHz의 진동수를 가지는 진동을 인가하여 실시할 수 있다.In addition, the step of applying the ultrasonic vibration in the method of the present invention can be carried out by applying a vibration having a frequency of 20kHz to 200MHz.
이때, 상기 초음파 진동을 가해주는 단계는 상기 겔 폴리머 전해질용 조성물을 주입하는 단계와 동시에 수행될 수 있다.In this case, the step of applying the ultrasonic vibration may be performed simultaneously with the step of injecting the gel polymer electrolyte composition.
또한, 본 발명의 방법은 포메이션하는 단계 후 및 겔 폴리머 전해질용 조성물을 경화하는 단계 전에 초음파 진동을 가해주는 단계를 추가로 포함할 수 있다.In addition, the method of the present invention may further comprise the step of applying an ultrasonic vibration after the step of forming and before the step of curing the composition for gel polymer electrolyte.
본 발명의 방법에 따르면, 겔 폴리머 전해질용 조성물 주입 시 또는 주입 후에 금속 소재의 초음파 부재를 이용하여 30℃ 이상의 온도에서 가압하는 동시에 초음파 진동을 가해줌으로써, 겔 폴리머 전해질용 조성물을 효과적으로 분산시켜 겔 폴리머 전해질용 조성물의 함침성을 개선할 수 있을 뿐만 아니라, 웨팅(wetting) 시간을 단축할 수 있다. 이에 따라, 초기 용량은 향상되고, 초기 저항 값은 낮아진 파우치형 이차전지를 제조할 수 있다.According to the method of the present invention, the gel polymer electrolyte composition is effectively dispersed by applying pressure at a temperature of 30 ° C. or more using an ultrasonic member made of a metal material or by applying ultrasonic vibrations at the time of injection or after injection of the gel polymer electrolyte composition. Not only can the impregnation of the composition for electrolyte be improved, but also the wetting time can be shortened. As a result, a pouch type secondary battery having an improved initial capacity and a lower initial resistance can be manufactured.
본 명세서에 첨부되는 다음의 도면은 본 발명의 바람직한 실시예를 예시하는 것이며, 전술한 발명의 내용과 함께 본 발명의 기술 사상을 더욱 이해시키는 역할을 하는 것이므로, 본 발명은 그러한 도면에 기재된 사항에만 한정되어 해석되어서는 아니다.The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the contents of the present invention serve to further understand the technical idea of the present invention, the present invention is limited to the matters described in such drawings. It is not to be construed as limited.
도 1은 본 발명의 일 실시예에 따른 파우치형 이차전지의 제조방법에서 초음파 부재가 배치된 파우치형 예비 이차전지의 단면도이다.1 is a cross-sectional view of a pouch type secondary battery in which an ultrasonic member is disposed in a method of manufacturing a pouch type secondary battery according to an exemplary embodiment of the present invention.
도 2는 본 발명의 실험예 1에 따른 파우치형 이차전지의 저항 평가 그래프이다.2 is a resistance evaluation graph of the pouch type secondary battery according to Experimental Example 1 of the present invention.
부호의 설명Explanation of the sign
100: 파우치형 예비 이차전지100: pouch type secondary battery
110-1: 제1 초음파 부재110-1: first ultrasonic member
110-2: 제2 초음파 부재110-2: second ultrasonic member
본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니 되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다.The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.
이하, 본 발명의 실시예에 따른 파우치형 이차전지의 제조방법을 첨부된 도면을 참조로 상세히 설명한다.Hereinafter, a method of manufacturing a pouch type secondary battery according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
구체적으로, 본 발명의 일 실시예에 따른 파우치형 이차전지의 제조 방법은Specifically, the manufacturing method of the pouch type secondary battery according to an embodiment of the present invention
파우치형 케이스의 내부 공간에 전극조립체를 수납하여 파우치형 예비(preliminary) 전지를 제조하는 단계;Manufacturing a pouch type preliminary battery by accommodating an electrode assembly in an inner space of the pouch type case;
파우치형 예비 이차전지의 양면에 금속 소재의 초음파 부재를 밀착하여 배치하는 단계;Disposing the ultrasonic member made of a metal material on both sides of the pouch type secondary battery;
상기 파우치형 예비 이차전지 내부에 겔 폴리머 전해질용 조성물을 주입하는 단계;Injecting a gel polymer electrolyte composition into the pouch-type preliminary secondary battery;
상기 초음파 부재를 이용하여 상기 파우치형 예비 이차전지를 가압하면서 파우치형 예비 이차전지에 초음파 진동을 가해주는 단계;Applying ultrasonic vibration to the pouch type secondary battery while pressurizing the pouch type secondary battery using the ultrasonic member;
상기 파우치형 예비 이차전지를 포메이션하는 단계;Forming the pouch type secondary battery;
상기 겔 폴리머 전해질용 조성물을 경화하는 단계; 및Curing the gel polymer electrolyte composition; And
탈기하는 단계;를 포함하며,Degassing; comprising;
상기 초음파 부재는 30℃ 내지 80℃의 온도를 유지하고,The ultrasonic member maintains a temperature of 30 ℃ to 80 ℃,
상기 파우치형 예비 이차전지를 가압하는 단계는 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 내지 3,000 kgf/㎠ 압력을 가하면서 실시할 수 있다. Pressing the pouch type preliminary secondary battery may be performed while applying a pressure of 0.1 Kgf / cm 2 to 3,000 kgf / cm 2 per area of the pouch type secondary battery.
파우치형 예비(preliminary) 전지를 제조하는 단계Manufacturing a pouch type preliminary cell
본 명세서에 따르면, 본 발명의 파우치형 예비 이차전지는 전극조립체와 상기 전극 조립체가 수납된 파우치형 케이스를 포함하며, 당 기술 분야에 알려진 통상적인 방법에 따라 제조할 수 있다. According to the present specification, the pouch type preliminary secondary battery of the present invention includes an electrode assembly and a pouch type case in which the electrode assembly is accommodated, and may be manufactured according to a conventional method known in the art.
예를 들면, 양극, 세퍼레이터 및 음극을 순차적으로 적층하여 전극 조립체를 형성한 다음, 이를 파우치형 (전지) 케이스에 수납하여 제조할 수 있다.For example, the positive electrode, the separator, and the negative electrode may be sequentially stacked to form an electrode assembly, and then may be housed in a pouch-type (battery) case.
이때, 상기 파우치형 케이스는 각각의 테두리에 실링부를 구비하기 때문에, 내부 공간에 전극조립체를 수납한 다음, 겔 폴리머 전해질용 조성물이 주입되는 1개의 모서리를 제외한 나머지 3개의 모서리를 먼저 밀봉하여 파우치형 예비 이차전지를 제조할 수 있다.At this time, since the pouch-type case is provided with a sealing portion at each rim, the electrode assembly is accommodated in the inner space, and then the remaining three corners except for one corner into which the gel polymer electrolyte composition is injected are first pouch-shaped. A spare secondary battery can be manufactured.
한편, 상기 전극조립체는 양극과 음극 사이에 세퍼레이터가 개재되어 서로 절연된 상태에서 순차적으로 적층되어 구성될 수 있으며, 실시형태에 따라 권취형, 스택형 또는 스택/폴딩형 등으로 다양한 구조로 형성될 수 있다. Meanwhile, the electrode assembly may be sequentially stacked in a state in which the separator is interposed between the positive electrode and the negative electrode and insulated from each other, and may be formed in various structures such as a winding type, a stack type, or a stack / fold type according to an embodiment. Can be.
이때, 상기 양극은 양극 집전체 상에 양극 합제층을 형성하여 제조할 수 있다. 상기 양극 합제층은 양극활물질, 바인더, 도전재 및 용매 등을 포함하는 양극 슬러리를 양극 집전체 상에 코팅한 후, 건조 및 압연하여 형성할 수 있다.In this case, the positive electrode may be manufactured by forming a positive electrode mixture layer on the positive electrode current collector. The cathode mixture layer may be formed by coating a cathode slurry including a cathode active material, a binder, a conductive material, a solvent, and the like on a cathode current collector, followed by drying and rolling.
상기 양극 집전체는 당해 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 스테인리스 스틸, 알루미늄, 니켈, 티탄, 소성 탄소, 또는 알루미늄이나 스테인리스 스틸의 표면에 카본, 니켈, 티탄, 은 등으로 표면 처리한 것 등이 사용될 수 있다. The positive electrode current collector is not particularly limited as long as it has conductivity without causing chemical changes in the battery. For example, the positive electrode current collector may be formed of stainless steel, aluminum, nickel, titanium, calcined carbon, or carbon on the surface of aluminum or stainless steel. Surface treated with nickel, titanium, silver, or the like may be used.
또한, 상기 양극 활물질은 리튬의 가역적인 인터칼레이션 및 디인터칼레이션이 가능한 화합물로서, 구체적으로는 코발트, 망간, 니켈 또는 알루미늄과 같은 1종 이상의 금속과 리튬을 포함하는 리튬 금속 산화물을 포함할 수 있다. 보다 구체적으로, 상기 리튬 금속 산화물은 리튬-망간계 산화물(예를 들면, LiMnO2, LiMn2O4 등), 리튬-코발트계 산화물(예를 들면, LiCoO2 등), 리튬-니켈계 산화물(예를 들면, LiNiO2 등), 리튬-니켈-망간계 산화물(예를 들면, LiNi1-YMnYO2(여기에서, 0<Y<1), LiMn2-zNizO4(여기에서, 0＜Z＜2) 등), 리튬-니켈-코발트계 산화물(예를 들면, LiNi1-Y1CoY1O2(여기에서, 0<Y1<1) 등), 리튬-망간-코발트계 산화물(예를 들면, LiCo1-Y2MnY2O2(여기에서, 0<Y2<1), LiMn2-z1Coz1O4(여기에서, 0＜Z1＜2) 등), 리튬-니켈-망간-코발트계 산화물(예를 들면, Li(NipCoqMnr1)O2(여기에서, 0＜p＜1, 0＜q＜1, 0＜r1＜1, p+q+r1=1) 또는 Li(Nip1Coq1Mnr2)O4(여기에서, 0＜p1＜2, 0＜q1＜2, 0＜r2＜2, p1+q1+r2=2) 등), 또는 리튬-니켈-코발트-전이금속(M) 산화물(예를 들면, Li(Nip2Coq2Mnr3MS2)O2(여기에서, M은 Al, Fe, V, Cr, Ti, Ta, Mg 및 Mo로 이루어지는 군으로부터 선택되고, p2, q2, r3 및 s2는 각각 자립적인 원소들의 원자분율로서, 0＜p2＜1, 0＜q2＜1, 0＜r3＜1, 0＜s2＜1, p2+q2+r3+s2=1이다) 등) 등을 들 수 있으며, 이들 중 어느 하나 또는 둘 이상의 화합물이 포함될 수 있다. In addition, the cathode active material is a compound capable of reversible intercalation and deintercalation of lithium, and specifically, may include a lithium metal oxide including lithium and one or more metals such as cobalt, manganese, nickel, or aluminum. Can be. More specifically, the lithium metal oxide may be lithium-manganese oxide (eg, LiMnO 2 , LiMn 2 O 4, etc.), lithium-cobalt oxide (eg, LiCoO 2, etc.), lithium-nickel oxide ( For example, LiNiO 2, etc., lithium-nickel-manganese oxides (eg, LiNi 1-Y Mn Y O 2 (here, 0 <Y <1), LiMn 2-z Ni z O 4 (here 0 <Z <2) and the like, lithium-nickel-cobalt-based oxide (for example, LiNi 1-Y1 Co Y1 O 2 (here, 0 <Y1 <1) and the like), lithium-manganese-cobalt-based Oxides (e.g., LiCo 1-Y2 Mn Y2 O 2 (here, 0 <Y2 <1), LiMn 2-z1 Co z1 O 4 (here, 0 <Z1 <2), etc.), lithium-nickel- Manganese-cobalt oxides (e.g., Li (Ni p Co q Mn r1 ) O 2 (where 0 <p <1, 0 <q <1, 0 <r1 <1, p + q + r1 = 1 ) Or Li (Ni p1 Co q1 Mn r2 ) O 4 (where 0 <p1 <2, 0 <q1 <2, 0 <r2 <2, p1 + q1 + r2 = 2, etc.), or lithium-nickel Cobalt-transition metal (M) oxides (e.g., Li (Ni p2 Co q2 Mn r3 M S2 ) O 2 , where M is A 1, Fe, V, Cr, Ti, Ta, Mg and Mo, and p2, q2, r3 and s2 are atomic fractions of freestanding elements, respectively, 0 <p2 <1, 0 <q2 <1 , 0 <r3 <1, 0 <s2 <1, p2 + q2 + r3 + s2 = 1), etc.), and any one or two or more of these compounds may be included.
상기 바인더는 활물질과 도전재 등의 결합과 집전체에 대한 결합에 조력하는 성분으로서, 통상적으로 양극 슬러리 중 고형분의 전체 중량을 기준으로 1 내지 30 중량%로 첨가될 수 있다. 이러한 바인더의 예로는, 폴리비닐리덴플루오라이드(PVDF), 폴리비닐알코올, 카르복시메틸셀룰로우즈(CMC), 전분, 히드록시프로필셀룰로우즈, 재생 셀룰로우즈, 폴리비닐피롤리돈, 테트라플루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌-프로필렌-디엔 테르 모노머, 술폰화 에틸렌-프로필렌-디엔 테르 모노머, 스티렌-부타디엔 고무, 불소 고무, 다양한 공중합체 등을 들 수 있다.The binder is a component that assists in bonding the active material, the conductive material, and the like to the current collector, and may generally be added in an amount of 1 to 30 wt% based on the total weight of solids in the positive electrode slurry. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoro Low ethylene, polyethylene, polypropylene, ethylene-propylene-diene monomers, sulfonated ethylene-propylene-diene monomers, styrene-butadiene rubbers, fluororubbers, various copolymers, and the like.
또한, 상기 도전재는 당해 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 양극 슬러리 중 고형분의 전체 중량을 기준으로 1 내지 20 중량%로 첨가될 수 있다.　이러한 도전재는 예를 들어, 카본블랙, 아세틸렌 블랙(또는 덴카 블랙), 케첸 블랙, 채널 블랙, 퍼니스 블랙, 램프 블랙, 또는 서멀 블랙 등의 탄소 분말; 결정구조가 매우 발달된 천연 흑연, 인조흑연, 또는 그라파이트 등의 흑연 분말; 탄소 섬유나 금속 섬유 등의 도전성 섬유; 불화 카본 분말, 알루미늄 분말, 니켈 분말 등의 도전성 분말 등이 사용될 수 있다. In addition, the conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and may be added in an amount of 1 to 20 wt% based on the total weight of solids in the positive electrode slurry. Such conductive materials include, for example, carbon powders such as carbon black, acetylene black (or denka black), Ketjen black, channel black, furnace black, lamp black, or thermal black; Graphite powders such as natural graphite, artificial graphite, or graphite with very advanced crystal structure; Conductive fibers such as carbon fibers and metal fibers; Conductive powders, such as carbon fluoride powder, aluminum powder, and nickel powder, etc. can be used.
상기 용매는 NMP(N-methyl-2-pyrrolidone) 등의 유기용매를 포함할 수 있으며, 상기 양극 활물질 및 선택적으로 바인더 및 도전재 등을 포함할 때 바람직한 점도가 되는 양으로 사용될 수 있다. 예를 들면, 양극 활물질, 및 선택적으로 바인더 및 도전재를 포함하는 슬러리 중의 고형분 농도가 10 중량% 내지 60 중량%, 바람직하게 20 중량% 내지 50 중량%가 되도록 포함될 수 있다.The solvent may include an organic solvent such as N-methyl-2-pyrrolidone (NMP), and may be used in an amount that becomes a desirable viscosity when including the positive electrode active material and optionally a binder and a conductive material. For example, the concentration of the solids in the slurry including the positive electrode active material and optionally the binder and the conductive material may be 10 wt% to 60 wt%, preferably 20 wt% to 50 wt%.
또한, 상기 양극은 양극 활물질층이 형성되지 않은 양극 집전체 영역, 즉 양극 무지부를 포함할 수 있고, 상기 양극은 무지부의 일측단에 금속 재질 이를 테면 알루미늄(Al) 재질로 형성되는 양극탭이 접합될 수 있다.In addition, the positive electrode may include a positive electrode current collector region, that is, a positive electrode non-coating portion, in which the positive electrode active material layer is not formed, and the positive electrode is bonded to a positive electrode tab formed of a metal material such as aluminum (Al) at one end of the non-coating portion. Can be.
또한, 상기 음극은 음극 집전체 상에 음극 합제층을 형성하여 제조할 수 있다. 상기 음극 합제층은 음극 집전체 상에 음극활물질, 바인더, 도전재 및 용매 등을 포함하는 음극 슬러리를 코팅한 후, 건조 및 압연하여 형성할 수 있다.In addition, the negative electrode may be prepared by forming a negative electrode mixture layer on the negative electrode current collector. The negative electrode mixture layer may be formed by coating a negative electrode slurry including a negative electrode active material, a binder, a conductive material, a solvent, and the like on a negative electrode current collector, followed by drying and rolling.
상기 음극 집전체는 일반적으로 3 내지 500㎛의 두께를 가진다. 이러한 음극 집전체는, 당해 전지에 화학적 변화를 유발하지 않으면서 높은 도전성을 가지는 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 구리, 스테인리스 스틸, 알루미늄, 니켈, 티탄, 소성 탄소, 구리나 스테인리스 스틸의 표면에 카본, 니켈, 티탄, 은 등으로 표면 처리한 것, 알루미늄-카드뮴 합금 등이 사용될 수 있다. The negative electrode current collector generally has a thickness of 3 to 500 μm. Such a negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver, and the like on the surface, aluminum-cadmium alloy and the like can be used.
또한, 상기 음극활물질은 리튬 금속, 리튬 이온을 가역적으로 인터칼레이션/디인터칼레이션할 수 있는 탄소 물질, 금속 또는 이들 금속과 리튬의 합금, 리튬을 도프 및 탈도프할 수 있는 물질, 및 전이 금속 산화물로 이루어진 군으로부터 선택된 적어도 하나 이상을 포함할 수 있다. In addition, the negative electrode active material is a lithium metal, a carbon material capable of reversibly intercalating / deintercalating lithium ions, a metal or an alloy of these metals with lithium, a material capable of doping and undoping lithium, and a transition It may include at least one selected from the group consisting of metal oxides.
상기 리튬 이온을 가역적으로 인터칼레이션/디인터칼레이션할 수 있는 탄소 물질로는, 리튬 이온 이차전지에서 일반적으로 사용되는 탄소계 음극 활물질이라면 특별히 제한 없이 사용할 수 있으며, 그 대표적인 예로는 결정질 탄소, 비정질 탄소 또는 이들을 함께 사용할 수 있다. As the carbon material capable of reversibly intercalating / deintercalating the lithium ions, any carbon-based negative electrode active material generally used in a lithium ion secondary battery may be used without particular limitation. Examples thereof include crystalline carbon, Amorphous carbons or these may be used together.
상기 금속 또는 이들 금속과 리튬의 합금으로는 Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al 및 Sn으로 이루어진 군에서 선택되는 금속 또는 이들 금속과 리튬의 합금이 사용될 수 있다.The metals or alloys of these metals with lithium include Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al And a metal selected from the group consisting of Sn or an alloy of these metals with lithium may be used.
상기 리튬을 도프 및 탈도프할 수 있는 물질로는 Si, SiOx(0<x≤2), Sn 또는 SnO2 등을 들 수 있고, 또한 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다.Examples of the material capable of doping and undoping lithium include Si, SiO x (0 <x ≦ 2), Sn, or SnO 2 , and may be used by mixing at least one of these with SiO 2 .
상기 전이 금속 산화물로는 리튬 함유 티타늄 산화물(LTO), 바나듐 산화물, 리튬 바나듐 산화물 등을 들 수 있다.Examples of the transition metal oxide include lithium-containing titanium oxide (LTO), vanadium oxide, lithium vanadium oxide, and the like.
한편, 상기 바인더 및 도전재는 상술한 바와 같이 양극 합제층에 사용된 바인더 및 도전재와 동일하거나 상이한 소재가 사용될 수 있다.On the other hand, the binder and the conductive material may be the same or different materials as the binder and the conductive material used in the positive electrode mixture layer as described above.
또한, 상기 용매는 물 또는 NMP, 알코올 등의 유기용매를 포함할 수 있으며, 상기 음극 활물질 및 선택적으로 바인더 및 도전재 등을 포함할 때 바람직한 점도가 되는 양으로 사용될 수 있다. 예를 들면, 음극 활물질, 및 선택적으로 바인더 및 도전재를 포함하는 슬러리 중의 고형분 농도가 50 중량% 내지 75 중량%, 바람직하게 50 중량% 내지 65 중량%가 되도록 포함될 수 있다.In addition, the solvent may include an organic solvent such as water or NMP, alcohol, etc., and may be used in an amount that becomes a desirable viscosity when including the negative electrode active material and optionally a binder and a conductive material. For example, the concentration of the solids in the slurry including the negative electrode active material and, optionally, the binder and the conductive material may be 50 wt% to 75 wt%, preferably 50 wt% to 65 wt%.
또한, 상기 음극은 양쪽 측부에 음극 활물질층이 형성되지 않은 음극 집전체 영역, 즉 음극 무지부가 형성될 수 있다. 그리고 음극은 일측단에 금속 재질, 이를테면 니켈(Ni) 재질로 형성되는 음극탭이 접합될 수 있다.In addition, the negative electrode may have a negative electrode current collector region, ie, a negative electrode non-coating portion, in which negative electrode active material layers are not formed at both sides. In addition, the negative electrode may be bonded to a negative electrode tab formed of a metal material, such as nickel (Ni), at one end thereof.
상기 양극탭 및 음극탭은 각각 전극조립체로부터 연장되며, 상기 각각의 탭은 외부 단자 또는 장치와의 전기적 연결 등을 위하여, 양극탭 및 음극탭의 일부나 전체가 각각 양극 리드 음극 리드에 연결될 수 있다. 상기 양극리드 및 음극리드는 전극탭들과 용접 등의 방법으로 전기적으로 연결되어 있고, 그 일부가 전지케이스의 외부로 노출될 수 있다. 양극리드와 음극리드는 전지케이스에서 서로 반대 방향으로 위치할 수도 있고, 동일한 방향에 나란히 위치할 수도 있다.Each of the positive electrode tab and the negative electrode tab extends from the electrode assembly, and each of the tabs may be partially or entirely connected to the positive electrode lead negative electrode lead, respectively, for electrical connection with an external terminal or device. . The positive lead and the negative lead are electrically connected to the electrode tabs by welding, and a part thereof may be exposed to the outside of the battery case. The positive lead and the negative lead may be located in opposite directions in the battery case, or may be located side by side in the same direction.
상기 세퍼레이터는 양극과 음극 사이에 위치하여, 양극과 음극을 서로 전기적으로 절연시키며, 양극과 음극 사이에서 리튬 이온 등이 서로 통과할 수 있도록 다공성막 형태로 형성될 수 있다. 이러한 세퍼레이터는, 예를 들어 폴리에틸렌(PE) 또는 폴리프로필렌(PP) 또는 이들의 복합필름을 사용한 다공성막으로 이루어질 수 있다. The separator is positioned between the positive electrode and the negative electrode to electrically insulate the positive electrode and the negative electrode from each other, and may be formed in the form of a porous membrane to allow lithium ions to pass between the positive electrode and the negative electrode. Such a separator may be made of, for example, a porous membrane using polyethylene (PE) or polypropylene (PP) or a composite film thereof.
초음파 부재를 밀착하여 배치하는 단계Placing the ultrasonic member in close contact
또한, 본 명세서에 따르면, 상기와 같이 제조된 파우치형 예비 이차전지의 양면에 파우치형 예비 이차전지 전면을 감싸는 금속 소재의 초음파 부재를 밀착하여 배치할 수 있다.In addition, according to the present specification, the ultrasonic member of the metal material surrounding the front surface of the pouch type preliminary secondary battery may be disposed on both sides of the pouch type preliminary secondary battery manufactured as described above.
도 1은 본 발명의 일 실시예에 따른 파우치형 이차전지의 제조방법에서 초음파 부재가 밀착하여 배치된 파우치형 예비 이차전지(100)의 단면도이다.1 is a cross-sectional view of a pouch-type preliminary secondary battery 100 in which an ultrasonic member is disposed in close contact with a method of manufacturing a pouch-type secondary battery according to an embodiment of the present invention.
도 1을 살펴보면, 본 발명의 방법은 전극조립체가 수납된 파우치형 예비 이차전지(100) 양면에 파우치형 예비 이차전지의 전면을 감싸는 초음파 부재를 밀착하여 배치할 수 있다.Referring to Figure 1, the method of the present invention may be disposed in close contact with the ultrasonic member surrounding the front surface of the pouch-type secondary battery 100 on both sides of the pouch-type secondary battery 100, the electrode assembly accommodated.
이때, 상기 초음파 부재는 도 1에 도시한 바와 같이 독립적으로 분리된 제1 초음파 부재(110-1) 및 제2 초음파 부재(110-2)로 이루어진 한 쌍의 초음파 부재일 수도 있고, 또는 제1 초음파 부재와 제2 초음파 부재의 적어도 일면이 결합되어 있는 일체형 초음파 부재일 수도 있다.In this case, the ultrasonic member may be a pair of ultrasonic members including the first ultrasonic member 110-1 and the second ultrasonic member 110-2 independently separated as shown in FIG. 1, or the first ultrasonic member. It may be an integrated ultrasonic member in which at least one surface of the ultrasonic member and the second ultrasonic member are coupled.
또한, 상기 초음파 부재는 접착 부재를 사용하지 않는 대신, 초음파 진동의 전달이 용이하도록 상기 파우치형 예비 이차전지의 케이스 측면과 서로 맞닿아 있는 것이 바람직하다.In addition, the ultrasonic member is preferably in contact with the side surface of the case of the pouch type preliminary secondary battery to facilitate the transmission of ultrasonic vibration, instead of using the adhesive member.
이러한 초음파 부재는 온도 조절과 압력 조절이 용이하도록 금속 소재로 이루어진 것이 바람직하다. 이러한 금속 소재로는 상기 금속은 스테인레스, 철, 알루미늄, 구리, 니켈 및 이들의 2종 이상의 합금으로 이루어진 군으로부터 선택된 적어도 하나를 들 수 있다. 구체적으로, 상기 초음파 부재는 비용 및 열 전달 효율 등을 고려하여 스테인레스 또는 알루미늄, 더욱 구체적으로 알루미늄으로 이루어질 수 있다.The ultrasonic member is preferably made of a metal material to facilitate temperature control and pressure control. The metal material may include at least one metal selected from the group consisting of stainless steel, iron, aluminum, copper, nickel and two or more alloys thereof. Specifically, the ultrasonic member may be made of stainless steel or aluminum, more specifically aluminum in consideration of cost and heat transfer efficiency.
본 발명의 방법에 있어서, 상기 초음파 부재는 일부분에 결합된 열선 등을 포함하는 온도 제어 장치(미도시)를 이용하여 30℃ 내지 80℃의 온도, 구체적으로 30℃ 내지 60℃의 온도를 유지하는 것이 바람직하다.In the method of the present invention, the ultrasonic member maintains a temperature of 30 ° C to 80 ° C, specifically 30 ° C to 60 ° C using a temperature control device (not shown) including a heating wire and the like coupled to a portion. It is preferable.
상기 초음파 부재가 상기 온도 범위를 유지함에 따라, 후속 겔 폴리머 전해질용 조성물 주입 시 함침 효과를 향상시킬 수 있으며, 초음파 진동을 가했을 때 파우치형 이차전지 내부에서 온도가 지나치게 상승하거나, 초음파 인가에 의한 내부 물질, 예컨대 전극의 활물질 등의 탈리 및 손상이 발생하는 것을 방지할 수 있다. 이때, 초음파 부재 온도가 30℃ 미만인 경우, 후속 겔 폴리머 전해질용 조성물 주입 시 겔 폴리머 전해질용 조성물의 점도가 높아져 함침성이 감소할 수 있고, 80℃를 초과하면 파우치형 이차전지 내부의 온도 상승에 의해 후속 겔 폴리머 전해질용 조성물 주입 시에 겔 폴리머 전해질용 조성물과 전극 또는 세퍼레이터 간의 화학적 물리적 부반응에 의한 손상을 초래하여 셀의 내부 단락을 야기할 수 있다.As the ultrasonic member maintains the temperature range, it is possible to improve the impregnation effect during subsequent injection of the composition for the gel polymer electrolyte, and when ultrasonic vibration is applied, the temperature rises excessively in the pouch-type secondary battery, or internally by ultrasonic application. Desorption and damage of a substance such as an active material of an electrode can be prevented from occurring. At this time, when the ultrasonic element temperature is less than 30 ℃, the viscosity of the gel polymer electrolyte composition may be increased during subsequent injection of the composition for gel polymer electrolyte, impregnation may be reduced, and if it exceeds 80 ℃, the temperature rise inside the pouch type secondary battery This may cause damage due to chemical and physical side reactions between the composition for gel polymer electrolyte and the electrode or separator upon subsequent injection of the composition for gel polymer electrolyte, thereby causing an internal short circuit of the cell.
겔 폴리머 전해질용 조성물을 주입하는 단계;Injecting the gel polymer electrolyte composition;
또한, 본 명세서에 따르면, 상기 파우치형 예비 이차전지의 양면에 파우치형 예비 이차전지의 전면을 감싸는 초음파 부재를 밀착하여 배치한 후, 개봉된 상태인 파우치형 케이스의 1개의 모서리를 통해 상기 전극조립체가 수납된 파우치형 케이스 내부에 겔 폴리머 전해질용 조성물을 주입할 수 있다.In addition, according to the present specification, after placing the ultrasonic member surrounding the front surface of the pouch-type preliminary secondary battery in close contact with both sides of the pouch-type preliminary secondary battery, the electrode assembly through one corner of the pouch-type case in an open state The gel polymer electrolyte composition may be injected into the pouch-type case in which is stored.
이때, 상기 겔 폴리머 전해질용 조성물의 주입구가 형성되는 면은 음극 탭 및 양극 탭이 걸쳐지는 실링부 면에 인접하되, 서로 다른 면인 것이 바람직하다.At this time, the surface in which the injection hole of the composition for the gel polymer electrolyte is formed is adjacent to the surface of the sealing portion in which the negative electrode tab and the positive electrode tab, but is preferably a different surface.
한편, 본 발명의 이차전지 제조 방법에서 사용되는 겔 폴리머 전해질용 조성물은 (a) 리튬염, (b) 유기용매, (c) 중합성 단량체, (d) 중합개시제 및 선택적으로 (e) 첨가제를 포함하는 것을 이용할 수 있다.On the other hand, the composition for gel polymer electrolyte used in the secondary battery manufacturing method of the present invention comprises (a) a lithium salt, (b) an organic solvent, (c) a polymerizable monomer, (d) a polymerization initiator and optionally (e) an additive. It can use to include.
이때, 상기 (a) 리튬염은 겔 폴리머 전해질에 통상적으로 포함되는 것들이 제한 없이 사용될 수 있으며, 예를 들어 양이온으로 Li+를 포함하고, 음이온으로는 F-, Cl-, Br-, I-, NO3 -, N(CN)2 -, ClO4 -, BF4 -, B10Cl10 -, PF6 -, CF3SO3 -, CH3CO2 -, CF3CO2 -, AsF6 -, SbF6 -, AlCl4 -, AlO4 -, CH3SO3 -, BF2C2O4 -, BC4O8 -, PF4C2O4 -, PF2C4O8 -, (CF3)2PF4 -, (CF3)3PF3 -, (CF3)4PF2 -, (CF3)5PF-, C4F9SO3 -, CF3CF2SO3 -, (FSO2)2N-, (CF3SO2)2N-, CF3CF2(CF3)2CO-, (CF3SO2)2CH-, (SF5)3C-, (CF3SO2)3C-, CF3(CF2)7SO3 -, SCN- 및 (CF3CF2SO2)2N-로 이루어진 군으로부터 선택된 적어도 어느 하나를 들 수 있다. In this case, the (a) lithium salt may be used without limitation those conventionally included in the gel polymer electrolyte, for example, include Li + as a cation, F − , Cl − , Br − , I − , NO 3 -, N (CN) 2 -, ClO 4 -, BF 4 -, B 10 Cl 10 -, PF 6 -, CF 3 SO 3 -, CH 3 CO 2 -, CF 3 CO 2 -, AsF 6 - , SbF 6 -, AlCl 4 - , AlO 4 -, CH 3 SO 3 -, BF 2 C 2 O 4 -, BC 4 O 8 -, PF 4 C 2 O 4 -, PF 2 C 4 O 8 -, ( CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, C 4 F 9 SO 3 -, CF 3 CF 2 SO 3 -, (FSO 2) 2 N -, (CF 3 SO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2) 2 CH -, (SF 5) 3 C -, (CF 3 SO 2) 3 C -, CF 3 (CF 2) 7 SO 3 - may be at least one selected from the group consisting of -, SCN -, and (CF 3 CF 2 SO 2) 2 N.
구체적으로, 상기 리튬염은 LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCH3CO2, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, LiAlO4, LiCH3SO3, LiFSI (lithium fluorosulfonyl imide, LiN(SO2F)2), LiTFSI (lithium (bis)trifluoromethanesulfonimide, LiN(SO2CF3)2) 및 LiBETI (lithium bisperfluoroethanesulfonimide, LiN(SO2C2F5)2)로 이루어진 군으로부터 선택된 단일물 또는 2종 이상의 혼합물을 포함할 수 있다. 더욱 구체적으로 리튬염은 LiBF4, LiPF6, LiCH3CO2, LiCF3CO2, LiCH3SO3, LiFSI, LiTFSI 및 LiBETI로 이루어진 군으로부터 선택된 단일물 또는 2종 이상의 혼합물을 포함할 수 있다. 이들 외에도 리튬 이차전지용 전해질에 통상적으로 사용되는 리튬염들이 제한 없이 사용할 수 있다. Specifically, the lithium salt is LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , LiAlO 4 , LiCH 3 SO 3 , LiFSI (lithium fluorosulfonyl imide, LiN (SO 2 F) 2 ), LiTFSI (lithium (bis) trifluoromethanesulfonimide, LiN (SO 2 CF 3 ) 2 ) and LiBETI (lithium bisperfluoroethanesulfonimide, LiN (SO 2 C 2 F 5) may comprise a 2) danilmul or in combination of two or more thereof selected from the group consisting of. More specifically, the lithium salt may include a single substance or a mixture of two or more selected from the group consisting of LiBF 4 , LiPF 6 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiCH 3 SO 3 , LiFSI, LiTFSI, and LiBETI. In addition to these, lithium salts commonly used in electrolytes for lithium secondary batteries can be used without limitation.
상기 리튬염은 통상적으로 사용 가능한 범위 내에서 적절히 변경할 수 있으나, 최적의 전극 표면의 부식 방지용 피막 형성 효과를 얻기 위하여, 겔 폴리머 전해질용 조성물 내에 0.8 M 내지 4.0 M의 농도, 구체적으로 1.0M 내지 3.0M 농도로 포함될 수 있다.The lithium salt may be appropriately changed within a range generally available, but in order to obtain an effect of forming an anti-corrosion coating on the surface of the electrode, a concentration of 0.8 M to 4.0 M in the composition for gel polymer electrolyte, specifically 1.0 M to 3.0 It may be included in M concentration.
상기 리튬염의 농도가 0.8M 미만이면, 리튬 이차전지의 저온 출력 개선 및 고온 저장 시 사이클 특성 개선의 효과가 미미하고, 4.0M 농도를 초과하면 겔 폴리머 전해질용 조성물의 점도가 증가함에 따라 겔 폴리머 전해질용 조성물의 함침성이 저하될 수 있다.When the concentration of the lithium salt is less than 0.8M, the effect of improving the low temperature output and the cycle characteristics of the lithium secondary battery during high temperature storage is insignificant, and when the concentration exceeds 4.0M, the gel polymer electrolyte increases as the viscosity of the gel polymer electrolyte composition increases. Impregnation of the composition may decrease.
또한, 상기 (b) 유기용매는 이차전지의 충방전 과정에서 산화 반응 등에 의한 분해가 최소화될 수 있고, 첨가제와 함께 목적하는 특성을 발휘할 수 있는 비수성 유기용매라면 제한이 없다. 예를 들면 카보네이트계 용매, 에테르계 용매 또는 에스테르계 용매 등을 각각 단독으로 또는 2종 이상 혼합하여 사용할 수 있다. In addition, the organic solvent (b) may be minimized as long as the organic solvent may be decomposed by an oxidation reaction or the like during the charging and discharging process of the secondary battery, and may be a non-aqueous organic solvent capable of exhibiting desired properties with an additive. For example, a carbonate solvent, an ether solvent, an ester solvent, etc. can be used individually or in mixture of 2 or more types, respectively.
상기 유기용매 중 카보네이트계 용매는 환형 카보네이트계 용매 또는 선형 카보네이트계 용매를 들 수 있다.Examples of the carbonate solvent in the organic solvent include a cyclic carbonate solvent or a linear carbonate solvent.
상기 환형 카보네이트계 용매의 구체적인 예로는 에틸렌 카보네이트(ethylene carbonate, EC), 프로필렌 카보네이트(propylene carbonate, PC), 1,2-부틸렌 카보네이트, 2,3-부틸렌 카보네이트, 1,2-펜틸렌카보네이트, 2,3-펜틸렌 카보네이트, 비닐렌 카보네이트 및 플루오로에틸렌 카보네이트 (FEC)으로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 용매를 들 수 있다.Specific examples of the cyclic carbonate solvent include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate , 2,3-pentylene carbonate, vinylene carbonate, and fluoroethylene carbonate (FEC), any one selected from the group consisting of, or two or more solvents thereof.
또한, 상기 선형 카보네이트계 용매는 디메틸 카보네이트(dimethyl carbonate, DMC), 디에틸 카보네이트(diethyl carbonate, DEC), 디프로필 카보네이트, 에틸메틸 카보네이트(EMC), 메틸프로필 카보네이트 및 에틸프로필 카보네이트로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 용매를 들 수 있다.In addition, the linear carbonate solvent is selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate and ethylpropyl carbonate Any one or two or more of these solvents can be mentioned.
상기 에테르계 용매로는 디메틸에테르, 디에틸에테르, 디프로필 에테르, 메틸에틸에테르, 메틸프로필 에테르 및 에틸프로필 에테르로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 용매를 들 수 있다.The ether solvent may be any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, and ethyl propyl ether or two or more of them.
또한, 상기 에스테르계 용매는 선형 에스테르계 용매 또는 환형 에스테르계 용매를 들 수 있으며, 이중 선형 에스테르계 용매는 그 구체적인 예로 메틸 아세테이트, 에틸 아세테이트, 프로필 아세테이트, 메틸 프로피오네이트, 에틸 프로피오네이트, 프로필 프로피오네이트, 및 부틸 프로피오네이트로 이루어진 군으로부터 선택되는 어느 하나 또는 이들 중 2종 이상의 용매를 들 수 있다.In addition, the ester solvent may include a linear ester solvent or a cyclic ester solvent, and examples of the linear ester solvent include methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, and propyl. One or two or more solvents selected from the group consisting of propionate and butyl propionate.
상기 환형 에스테르계 용매는 그 구체적인 예로 γ-부티로락톤, γ-발레로락톤, γ-카프로락톤, σ-발레로락톤 또는 ε-카프로락톤 등을 들 수 있다.Specific examples of the cyclic ester solvent include γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone or ε-caprolactone.
또한, 상기 (c) 중합성 단량체는 서로 중합되어 폴리머를 형성할 수 있도록 분자 내에 아크릴레이트기가 적어도 하나 이상 함유된 다기능성 아크릴레이트계 화합물, 메타크릴레이트기가 적어도 하나 이상 함유된 다기능성 메타크릴레이트계 화합물, 또는 비닐기, 에폭시기, 에테르기, 알릴(allyl)기, 옥시알킬렌기 및 (메타)아크릴기로 이루어진 군에서 선택되는 중합성 관능기를 갖는 화합물들을 포함할 수 있다.In addition, the (c) polymerizable monomer is a multifunctional acrylate compound containing at least one acrylate group in the molecule, and a multifunctional methacrylate containing at least one methacrylate group so as to polymerize with each other to form a polymer. Or a compound having a polymerizable functional group selected from the group consisting of a vinyl group, an epoxy group, an ether group, an allyl group, an oxyalkylene group, and a (meth) acryl group.
구체적으로, 상기 중합성 단량체는 하기 화학식 1로 표시되는 화합물을 들 수 있다.Specifically, the polymerizable monomer may be a compound represented by the following formula (1).
[화학식 1][Formula 1]
A-B-A'A-B-A '
상기 화학식 1에서, In Chemical Formula 1,
상기 A 및 A'는 각각 독립적으로 아크릴레이트기, 메타크릴레이트기, 적어도 하나 이상의 아크릴레이트기 또는 메타크릴레이트기를 함유하는 탄소수 1 내지 10의 알킬렌기, 또는 -O-R1이고, 이때 상기 R1은 적어도 하나 이상의 아크릴레이트기 또는 메타크릴레이트기를 함유하는 탄소수 1 내지 10의 알킬렌기, 또는 -O-R2-O-R3이며, 이때 상기 R2 및 R3은 각각 적어도 하나 이상의 아크릴레이트기 또는 메타크릴레이트기를 함유하는 탄소수 1 내지 10의 알킬렌기이고, A and A 'are each independently an acrylate group, a methacrylate group, an alkylene group having 1 to 10 carbon atoms containing at least one or more acrylate groups or methacrylate groups, or -OR 1 , wherein R 1 is An alkylene group having 1 to 10 carbon atoms or at least one or more acrylate groups or methacrylate groups, or -OR 2 -OR 3 , wherein R 2 and R 3 are each at least one acrylate group or methacrylate group; It is a C1-C10 alkylene group containing,
상기 B는 옥시알킬렌기이다.B is an oxyalkylene group.
구체적으로, 상기 A 및 A'는 각각 독립적으로 하기 화학식 A-1 내지 화학식 A-5로 표시되는 단위 중 적어도 하나 이상을 포함할 수 있다.Specifically, A and A 'may each independently include at least one or more of the units represented by Formulas A-1 to A-5.
[화학식 A-1][Formula A-1]
Figure PCTKR2019003403-appb-I000001
Figure PCTKR2019003403-appb-I000001
[화학식 A-2][Formula A-2]
Figure PCTKR2019003403-appb-I000002
Figure PCTKR2019003403-appb-I000002
[화학식 A-3][Formula A-3]
Figure PCTKR2019003403-appb-I000003
Figure PCTKR2019003403-appb-I000003
[화학식 A-4][Formula A-4]
Figure PCTKR2019003403-appb-I000004
Figure PCTKR2019003403-appb-I000004
[화학식 A-5][Formula A-5]
Figure PCTKR2019003403-appb-I000005
Figure PCTKR2019003403-appb-I000005
상기 중합성 단량체의 말단에 위치하는 아크릴레이트기 또는 메타크릴레이트기는 에틸렌성 불포화기를 포함하는 유기 바인더와의 중합 반응으로 폴리머 네트워크를 형성할 수 있다. 이러한 화합물은 단관능성 또는 다관능성 아크릴레이트기 또는 메타크릴레이트기를 포함하는 단량체로부터 유도될 수 있다.An acrylate group or methacrylate group positioned at the terminal of the polymerizable monomer may form a polymer network by a polymerization reaction with an organic binder including an ethylenically unsaturated group. Such compounds can be derived from monomers comprising mono or polyfunctional acrylate groups or methacrylate groups.
또한, 상기 B는 하기 화학식 B-1로 표시되는 단위를 포함할 수 있다.In addition, the B may include a unit represented by the following formula (B-1).
[화학식 B-1][Formula B-1]
Figure PCTKR2019003403-appb-I000006
Figure PCTKR2019003403-appb-I000006
상기 화학식 B-1에서, In Chemical Formula B-1,
R은 탄소수 1 내지 10의 알킬렌기이고, R is an alkylene group having 1 to 10 carbon atoms,
R3는 O 또는 탄소수 1 내지 5의 알킬렌기이며,R 3 is O or an alkylene group having 1 to 5 carbon atoms,
k1은 1 내지 30 중 어느 하나의 정수이고,k1 is an integer of any one of 1 to 30,
m은 0 내지 3 중 어느 하나의 정수이다.m is an integer of any one of 0-3.
예를 들어, 상기 화학식 B-1에서, 상기 R은 각각 독립적으로 -CH2CH2- 또는 -CH2CH2CH2- 일 수 있다.For example, in Formula B-1, R may be each independently -CH 2 CH 2 -or -CH 2 CH 2 CH 2- .
보다 구체적으로, 상기 화학식 1로 표시되는 화합물은 하기 화학식 1a로 나타낼 수 있다.More specifically, the compound represented by Chemical Formula 1 may be represented by the following Chemical Formula 1a.
[화학식 1a][Formula 1a]
Figure PCTKR2019003403-appb-I000007
Figure PCTKR2019003403-appb-I000007
상기 중합성 단량체는 상기 겔 폴리머 전해질용 조성물의 전체 중량을 기준으로 0.5 중량% 내지 20 중량%, 구체적으로 0.7 중량% 내지 15 중량%, 더욱 구체적으로 1.0 중량% 내지 10 중량%로 포함될 수 있다.The polymerizable monomer may be included in an amount of 0.5 wt% to 20 wt%, specifically 0.7 wt% to 15 wt%, and more specifically 1.0 wt% to 10 wt%, based on the total weight of the gel polymer electrolyte composition.
상기 중합성 단량체의 함량이 0.5 중량% 이상인 경우에 겔 반응 형성 효과가 향상되어 겔 폴리머 전해질의 충분한 기계적 강도를 확보할 수 있고, 20 중량% 이하인 경우에 과량이 올리고머 함량에 따른 저항 증가 및 리튬 이온의 이동이 제한(이온전도도 감소)과 같은 단점을 방지할 수 있다. When the content of the polymerizable monomer is 0.5% by weight or more, the effect of forming a gel reaction can be improved to secure sufficient mechanical strength of the gel polymer electrolyte, and when the content is 20% by weight or less, an increase in resistance according to the oligomer content and a lithium ion It is possible to avoid disadvantages such as the limitation of (limiting ion conductivity).
또한, 상기 (d) 중합개시제는 당 업계에 알려진 통상적인 중합개시제가 사용될 수 있다. 예를 들면, 상기 중합개시제는 UV 중합개시제, 광 중합개시제, 및 열 중합개시제로 이루어진 군에서 선택된 1종 이상을 선택하여 사용할 수 있다.In addition, the polymerization initiator (d) may be used a conventional polymerization initiator known in the art. For example, the polymerization initiator may be used by selecting one or more selected from the group consisting of a UV polymerization initiator, a photo polymerization initiator, and a thermal polymerization initiator.
구체적으로, 상기 UV 중합개시제는 대표적인 예로 2-히드록시-2-메틸프로피오페논, 1-히드록시-시클로헥실페닐-케톤, 벤조페논, 2-히드록시-1-[4-(2-히드록시에톡시)페닐]-2-메틸-1-프로파논, 옥시-페닐아세틱 애씨드 2-[2-옥소-2 페닐-아세톡시-에톡시]-에틸 에스테르, 옥시-페닐-아세틱 2-[2-히드록시에톡시]-에틸 에스테르, 알파-디메톡시-알파-페닐아세토페논, 2-벤질-2-(디메틸아미노)-1-[4-(4-몰포리닐)페닐]-1-부타논, 2-메틸-1-[4-(메틸티오)페닐]-2-(4-몰포리닐)-1-프로파논, 디페닐 (2,4,6-트리메틸벤조일)-포스핀 옥사이드, 비스(2,4,6-트리메틸 벤조일)-페닐 포스핀 옥사이드, 비스(에타 5-2,4-시클로펜타디엔-1-일), 비스[2,6-디플루오로-3-(1H-피롤-1-일)페닐]티타늄, 4-이소부틸페닐-4'-메틸페닐아이오도늄, 헥사플루오로포스페이트, 및 메틸 벤조일포메이트로 이루어진 군으로부터 선택된 적어도 하나 이상을 포함할 수 있다.Specifically, the UV polymerization initiator is a representative example of 2-hydroxy-2-methylpropiophenone, 1-hydroxy-cyclohexylphenyl-ketone, benzophenone, 2-hydroxy-1- [4- (2-hydroxy Oxyethoxy) phenyl] -2-methyl-1-propaneone, oxy-phenylacetic acid 2- [2-oxo-2 phenyl-acetoxy-ethoxy] -ethyl ester, oxy-phenyl-acetic 2- [2-hydroxyethoxy] -ethyl ester, alpha-dimethoxy-alpha-phenylacetophenone, 2-benzyl-2- (dimethylamino) -1- [4- (4-morpholinyl) phenyl] -1 -Butanone, 2-methyl-1- [4- (methylthio) phenyl] -2- (4-morpholinyl) -1-propanone, diphenyl (2,4,6-trimethylbenzoyl) -phosphine Oxide, bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide, bis (eta 5-2,4-cyclopentadien-1-yl), bis [2,6-difluoro-3- ( Group consisting of 1H-pyrrole-1-yl) phenyl] titanium, 4-isobutylphenyl-4'-methylphenyliodonium, hexafluorophosphate, and methyl benzoylformate From it may include at least one or more selected.
또한, 상기 광 또는 열 중합개시제는 그 대표적인 예로 벤조일 퍼옥사이드(benzoyl peroxide), 아세틸 퍼옥사이드(acetyl peroxide), 디라우릴 퍼옥사이드(dilauryl peroxide), 디-tert-부틸 퍼옥사이드(di-tert-butyl peroxide), t-부틸 퍼옥시-2-에틸-헥사노에이트(t-butyl peroxy-2-ethyl-hexanoate), 큐밀 하이드로퍼옥사이드(cumyl hydroperoxide) 및 하이드로겐 퍼옥사이드(hydrogen peroxide), 2,2'-아조비스(2-시아노부탄), 2,2'-아조비스(메틸부티로니트릴), 2,2'-아조비스(이소부티로니트릴)(AIBN; 2,2'-Azobis(iso-butyronitrile)) 및 2,2'-아조비스디메틸-발레로니트릴(AMVN; 2,2'-Azobisdimethyl-Valeronitrile)로 이루어진 군에서 선택된 적어도 하나 이상을 포함할 수 있다.In addition, the photo or thermal polymerization initiator is a typical example of benzoyl peroxide, acetyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide. peroxide, t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide and hydrogen peroxide, 2,2 '-Azobis (2-cyanobutane), 2,2'-azobis (methylbutyronitrile), 2,2'-azobis (isobutyronitrile) (AIBN; 2,2'-Azobis (iso -butyronitrile)) and 2,2'-azobisdimethyl-valeronitrile (AMVN; 2,2'-Azobisdimethyl-Valeronitrile).
상기 중합개시제는 전지 내에서 UV, 또는 30℃ 내지 100℃의 열에 의해 분해되거나 상온(5℃ 내지 30℃)에서 광(light)에 의해 분해되어 라디칼을 형성할 수 있는 화합물로서, 상기 화학식 1로 표시되는 폴리머(A) 100 중량부에 대하여 0.1 중량부 내지 10 중량부의 양으로 사용될 수 있다. 중합개시제가 10 중량부 이하로 포함되는 경우 고분자 전해질 내에서 중합 속도를 제어할 수 있어 미반응 중합개시제가 잔류하여 나중에 전지 성능에 악영향을 미치는 단점을 방지할 수 있다. 또한, 중합개시제가 0.1 중량부 이상 포함되어야 화학식 1로 표시되는 폴리머(A) 화합물 간 중합 반응이 원활하게 이루어져, 균일한 두께의 고분자 전해질이 제조될 수 있다.The polymerization initiator is a compound which can be decomposed by UV or heat in a battery at 30 ° C. to 100 ° C. or decomposed by light at room temperature (5 ° C. to 30 ° C.) to form radicals. It can be used in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polymer (A) to be displayed. When the polymerization initiator is included in 10 parts by weight or less, it is possible to control the polymerization rate in the polymer electrolyte, thereby preventing the disadvantage that the unreacted polymerization initiator remains and later adversely affects the battery performance. In addition, the polymerization initiator should be included 0.1 parts by weight or more to facilitate the polymerization reaction between the polymer (A) compound represented by the formula (1), a polymer electrolyte having a uniform thickness can be prepared.
또한, (e) 상기 첨가제는 겔 폴리머 전해질에 통상적으로 사용되는 것들이 제한 없이 사용될 수 있으며, 그 대표적인 예로 비닐렌카보네이트(VC), 프로판 설톤(PS), 숙시노니트릴(SN), 아디포니트릴, 에틸렌 설파이트(ESa), 1,3-프로판 설톤(PRS), 프로필렌에틸렌 카보네이트(FEC), LiPO2F2, LiODFB, LiBOB, 테트라메틸 트리메틸 실릴 포스페이트(TMSPa), 트리메틸 실릴 포스파이트 (TMSPi), 리튬 디플루오로(비스옥살라토)포스페이트, 리튬 디플루오로포스페이트, 리튬 옥살릴디플루오로보레이트, 트리스(2,2,2-트리플루오로에틸)포스페이트(TFEPa) 또는 트리스(트리플루오로에틸) 포스파이트(TFEPi) 등을 적어도 하나 이상 포함할 수 있다.In addition, (e) the additive may be used without limitation those conventionally used in the gel polymer electrolyte, and representative examples thereof include vinylene carbonate (VC), propane sultone (PS), succinonitrile (SN), adiponitrile, Ethylene sulfite (ESa), 1,3-propane sultone (PRS), propylene ethylene carbonate (FEC), LiPO 2 F 2 , LiODFB, LiBOB, tetramethyl trimethyl silyl phosphate (TMSPa), trimethyl silyl phosphite (TMSPi), Lithium difluoro (bisoxalato) phosphate, lithium difluorophosphate, lithium oxalyldifluoroborate, tris (2,2,2-trifluoroethyl) phosphate (TFEPa) or tris (trifluoroethyl Phosphite (TFEPi) and the like.
본 발명의 방법에서는 상기 겔 폴리머 전해질용 조성물을 주입한 다음, 개봉된 실링부를 서로 접착하여 밀봉한 다음 후속 공정을 실시할 수도 있다.In the method of the present invention, after injecting the composition for the gel polymer electrolyte, the opened sealing parts may be adhered to each other and sealed, followed by a subsequent step.
즉, 초음파 진동을 가하는 전에 상기 겔 폴리머 전해질용 조성물 주입구를 밀봉함으로써, 겔 폴리머 전해질용 조성물이 휘발되거나, 파우치형 케이스가 개봉 상태에서 발생할 수 있는 전지 내부 오염 등을 방지할 수 있다.That is, the gel polymer electrolyte composition injection port is sealed before the ultrasonic vibration is applied, so that the gel polymer electrolyte composition may be volatilized, or the inside of the battery may be prevented from occurring in the pouch-type case.
상기 밀봉은 파우치형 케이스의 폴리머층이 서로 접착될 수 있도록, 130℃ 내지 160℃에서 1초 내지 10초, 구체적으로 140℃ 내지 150℃에서 2초 내지 3초 동안 실시할 수 있다.The sealing may be performed for 1 second to 10 seconds at 130 ° C. to 160 ° C., specifically for 2 seconds to 3 seconds at 140 ° C. to 150 ° C., so that the polymer layers of the pouch type case may be adhered to each other.
초음파 진동을 가해주는 단계Step to apply ultrasonic vibration
또한, 본 발명의 방법에서, 상기 겔 폴리머 전해질용 조성물을 주입 후, 상기 파우치형 예비 이차전지의 케이스 양측면에 밀착 배치된 초음파 부재를 통하여 상기 파우치형 예비 이차전지를 가압하면서 초음파 진동을 가해줄 수 있다.In addition, in the method of the present invention, after injecting the composition for the gel polymer electrolyte, it is possible to apply ultrasonic vibration while pressing the pouch-type preliminary secondary battery through an ultrasonic member disposed in close contact with both sides of the case of the pouch-type preliminary secondary battery. have.
상기 초음파 진동을 가해주는 단계는 20kHz 내지 200 MHz, 구체적으로 31kHz 내지 200 MHz의 진동수를 가지는 진동을 인가하여 수행될 수 있다. 상기 초음파 진동을 20 kHz 미만으로 실시하는 경우, 파우치형 케이스 내부에 주입된 겔 폴리머 전해질용 조성물이 미립자로 분해되기 어렵기 때문에 겔 폴리머 전해질용 조성물의 함침성 향상 효과가 미미할 수 있다. 초음파 진동을 200 MHz 초과하여 실시하는 경우, 전력소비가 지나치게 높아져 생산성이 저하될 수 있다. The step of applying the ultrasonic vibration may be performed by applying a vibration having a frequency of 20kHz to 200MHz, specifically 31kHz to 200MHz. When the ultrasonic vibration is performed at less than 20 kHz, since the composition for gel polymer electrolyte injected into the pouch type case is hardly decomposed into fine particles, the effect of improving the impregnation of the composition for gel polymer electrolyte may be insignificant. In the case where ultrasonic vibration is performed in excess of 200 MHz, power consumption may be excessively high, which may lower productivity.
또한, 상기 초음파 진동을 가하는 동시에 유압 프레스 등을 이용하여 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 내지 3,000 kgf/㎠ 압력, 구체적으로 0.1 Kgf/㎠ 내지 500 kgf/㎠ 압력, 더욱 구체적으로 0.1 Kgf/㎠ 내지 100 kgf/㎠ 압력, 구체적으로 더욱 구체적으로 0.1 Kgf/㎠ 내지 50 kgf/㎠ 압력을 가하면서 상기 파우치형 예비 이차전지를 가압할 수 있다.In addition, 0.1 Kgf / ㎠ to 3,000 kgf / ㎠ pressure, specifically 0.1 Kgf / ㎠ to 500 kgf / ㎠ pressure, more specifically 0.1 Kgf / per pouch type secondary battery by using the hydraulic press, etc. while applying the ultrasonic vibration The pouch type secondary battery may be pressurized while applying a pressure of cm 2 to 100 kgf / cm 2, more specifically, 0.1 Kgf / cm 2 to 50 kgf / cm 2.
상기 범위의 압력을 가하는 경우, 겔 폴리머 전해질용 조성물의 분산 효과를 보다 향상시킬 수 있다. 이때 상기 압력을 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 미만으로 가하는 경우 셀 내부까지 초음파 진동이 전달되기 어려울 수 있고, 파우치형 예비 이차전지 면적당 3,000 kgf/㎠을 초과하는 압력을 가하는 경우 파우치형 이차전지에 지나치게 높은 압력이 가해져 셀 손상을 야기할 수 있다. When applying the pressure of the said range, the dispersion effect of the composition for gel polymer electrolytes can be improved more. At this time, when the pressure is applied to less than 0.1 Kgf / ㎠ per area of the pouch type secondary battery, it may be difficult to transmit the ultrasonic vibration to the inside of the cell, when applying a pressure exceeding 3,000 kgf / ㎠ per area of the pouch type secondary battery pouch type secondary Excessively high pressure may be applied to the cell causing cell damage.
상기 초음파 진동을 가해주는 단계는 5초 내지 10초 동안 초음파 진동을 가한 후, 5초 내지 10초 동안 휴식기를 가지는 사이클을 1 사이클로 하여, 상기 사이클을 약 50회 내지 150회, 구체적으로 약 100회 반복하여 실시할 수 있다.The step of applying the ultrasonic vibration is a cycle having a rest for 5 seconds to 10 seconds after applying ultrasonic vibration for 5 seconds to 10 seconds, the cycle about 50 to 150 times, specifically about 100 times Can be repeated.
이때, 본 발명의 방법에서, 상기 초음파 부재는 파우치형 예비 이차전지 전면을 완전히 감싸는 형태로 형성되어 있기 때문에, 파우치형 예비 이차전지 내부의 열 손실을 막아 보다 안정적으로 셀 내부 온도를 유지할 수 있을 뿐만 아니라, 파우치형 예비 이차전지 전면에 균일한 압력 및 초음파 진동을 가할 수 있고, 더불어 초음파 진동을 가해줄 때 발생하는 소음을 줄여 작업 환경을 개선할 수 있다. At this time, in the method of the present invention, since the ultrasonic member is formed to completely surround the front surface of the pouch-type preliminary secondary battery, it is possible to prevent the heat loss inside the pouch-type preliminary secondary battery and more stably maintain the cell temperature. In addition, uniform pressure and ultrasonic vibration may be applied to the front surface of the pouch type preliminary secondary battery, and the working environment may be improved by reducing noise generated when ultrasonic vibration is applied.
이때, 본 발명의 방법에서 상기 초음파 진동을 가해주는 단계는 상기 겔 폴리머 전해질용 조성물을 주입하는 동시에 수행될 수도 있고, 또는 상기 겔 폴리머 전해질용 조성물을 주입 완료하고, 밀봉한 다음 수행할 수도 있다. In this case, the step of applying the ultrasonic vibration in the method of the present invention may be performed at the same time as the injection of the composition for the gel polymer electrolyte, or may be performed after the injection of the composition for the gel polymer electrolyte is completed, sealed.
본 발명의 방법에서와 같이, 겔 폴리머 전해질용 조성물 주입 시 또는 주입 후 초음파 진동을 가하는 경우, 겔 폴리머 전해질용 조성물의 점도가 낮아지고 분자의 운동성이 향상되어 전극조립체를 구성하는 전극판 및 세퍼레이터로 함침되기가 보다 용이하므로, 겔 폴리머 전해질용 조성물의 함침성(젖음성)이 크게 향상될 수 있다. 이에, 겔 폴리머 전해질용 조성물의 주입 후 파우치형 이차전지의 웨팅 시간과 이에 따른 제조 시간을 단축할 수 있다.As in the method of the present invention, when the gel polymer electrolyte composition is injected or when ultrasonic vibration is applied, the viscosity of the gel polymer electrolyte composition is lowered and the mobility of the molecules is improved to form an electrode plate and a separator constituting the electrode assembly. Since it is easier to impregnate, the impregnability (wetting) of the composition for gel polymer electrolyte can be greatly improved. Thus, after the injection of the gel polymer electrolyte composition, it is possible to shorten the wetting time and the manufacturing time of the pouch type secondary battery.
특히, 본 발명의 방법에서는 겔 폴리머 전해질용 조성물을 주입하고 밀봉한 다음 초음파 진동을 가함으로써, 겔 폴리머 전해질용 조성물의 프리-겔화 반응성을 억제할 수 있다.In particular, in the method of the present invention, pre-gelling reactivity of the gel polymer electrolyte composition can be suppressed by injecting and sealing the gel polymer electrolyte composition and then applying ultrasonic vibration.
한편, 본 발명의 파우치형 이차전지 제조 방법에서는 상기 초음파 진동이 가해질 때, 초음파 부재를 이용하여 초음파 진동에 의해 야기되는 파우치형 예비 이차전지 내부의 발열 온도 범위를 제어할 수 있다.On the other hand, in the pouch type secondary battery manufacturing method of the present invention, when the ultrasonic vibration is applied, it is possible to control the heat generation temperature range inside the pouch type secondary battery caused by the ultrasonic vibration using the ultrasonic member.
포메이션하는 단계Formation Steps
본 명세서에서, 상기 초음파 진동을 가해주는 단계 후에 파우치형 예비 이차전지를 포메이션하는 단계를 실시할 수 있다.In the present specification, the step of forming the pouch type secondary battery may be performed after the step of applying the ultrasonic vibration.
상기 포메이션 단계는 70℃ 이하에서 0.05C 내지 0.1C에서 100 내지 200mA로 1.7V 내지 4.4V까지 충방전을 실시할 수 있고, 구체적으로 0.05C에서 1.7V까지 실시할 수 있다.The formation step may be charged and discharged up to 1.7V to 4.4V at 100C to 200mA at 0.05C to 0.1C at 70 ° C or less, and specifically, may be performed to 0.05V at 0.05C.
또한, 본 발명의 방법은 상기 포메이션하는 단계 후에, 에이징하는 단계를 추가로 실시할 수 있다.In addition, the method of the present invention may further perform the aging step after the forming step.
상기 에이징하는 단계는 프리겔화를 방지하고 전극이 겔 폴리머 전해질용 조성물에 충분히 젖을 수 있도록 상온에서 25℃ 내지 60℃, 구체적으로 30℃ 내지 40℃ 상온하에서 1시간 내지 72시간 (3일) 이내로 실시할 수 있다.The aging step is carried out within 1 hour to 72 hours (3 days) at room temperature of 25 ℃ to 60 ℃, specifically 30 ℃ to 40 ℃ room temperature to prevent pregelation and sufficiently wet the electrode in the composition for gel polymer electrolyte can do.
본 발명의 방법에서는 상기 포메이션 공정 및 상기 에이징 과정을 70℃ 이하에서 실시함으로써, 충분한 SEI 막을 형성할 수 있고, 웨팅성 향상 효과와 전해질염 분해 반응을 제어하여 부반응을 방지할 수 있다. In the method of the invention the formation By carrying out the process and the aging process at 70 ° C. or less, a sufficient SEI film can be formed, and side reactions can be prevented by controlling the wetting property improving effect and the electrolyte salt decomposition reaction.
또한, 본 발명의 방법은 상기 에이징 단계 이후에 웨팅성 향상을 위하여, 진공 웨팅 단계를 추가로 실시할 수도 있다.In addition, the method of the present invention may further perform a vacuum wetting step after the aging step to improve the wettability.
상기 진공 웨팅 단계는 종래 실시하던 웨팅 조건보다 약한 진공 압력상태에서 짧은 시간 동안 노출시키는 것이 바람직한데, 구체적으로 진공 챔버 내에서 10초 내지 20초 동안 감압하면서 3회 반복 실시할 수 있으며, 보다 구체적으로 15초 내지 20초 동안 감압하면서 3회 반복 실시할 수 있다. The vacuum wetting step is preferably exposed for a short period of time under a weaker vacuum pressure than the conventional wetting conditions. Specifically, the vacuum wetting step may be repeated three times while reducing the pressure for 10 to 20 seconds in a vacuum chamber. It may be repeated three times while reducing the pressure for 15 to 20 seconds.
한편, 본 발명의 방법에서 상기 포메이션 단계를 실시할 때, 양극 활물질에서 기인하는 가스와 양극 활물질과 겔 폴리머 전해질용 조성물과의 부반응으로 인해 생성된 가스가 다량으로 발생할 수 있다. 만약, 상기 포메이션 단계에서 전지셀 내부에 발생한 가스가 효율적으로 제거되지 않으면 가스가 전지셀 내부에서 일정 공간을 차지함으로써 포메이션이 균일하게 이루어지는 것을 방해하여, 용량 및 출력 등의 전지 성능 및 전지 수명에 악영향을 미치게 된다. 더욱이, 전지셀 내부에 잔존하는 가스에 의해 전지의 용량은 충방전 횟수가 늘어남에 따라 급격하게 저하되거나, 전지셀이 부풀어 오르게 되는 등의 문제가 있다.On the other hand, when performing the formation step in the method of the present invention, a large amount of gas generated due to the side reaction of the gas resulting from the positive electrode active material and the composition for the positive electrode active material and the gel polymer electrolyte may occur. If the gas generated in the battery cell is not efficiently removed in the formation step, the gas occupies a certain space in the battery cell, thereby preventing the formation of uniformly, adversely affecting battery performance and battery life such as capacity and output. Get mad. In addition, there is a problem that the capacity of the battery decreases rapidly as the number of charge / discharge increases due to the gas remaining inside the battery cell, or the battery cell swells.
따라서, 본 발명의 방법에서는 포메이션 단계 후에, 케이스 일부 영역을 개봉하여 상기 포메이션 단계에서 발생하는 가스를 탈기(degas)하는 단계를 추가로 포함할 수 있다.Therefore, the method of the present invention may further include degassing the gas generated in the formation step by opening a portion of the case after the formation step.
또한, 본 발명의 방법은 상기 탈기 단계 후에 초음파 진동을 가해주는 단계를 추가로 포함할 수도 있다.In addition, the method may further comprise applying ultrasonic vibration after the degassing step.
상기 초음파 진동을 가해주는 단계는 전술한 초음파 진동을 가해주는 단계와 동일한 조건하에서 실시할 수 있다. The step of applying the ultrasonic vibration can be carried out under the same conditions as the step of applying the ultrasonic vibration described above.
이와 같이, 본 발명의 방법에서는 겔 폴리머 전해질 제조를 위한 경화 공정 전에 여러 단계의 초음파 진동 단계를 실시함으로써, 겔 폴리머 전해질용 조성물의 분산성을 향상시켜 함침성을 높임으로써, 더욱 더 균일하고 안정적으로 겔 폴리머 전해질을 경화할 수 있다. As described above, in the method of the present invention, by performing various ultrasonic vibration steps before the curing process for preparing the gel polymer electrolyte, the dispersibility of the composition for the gel polymer electrolyte is improved to increase the impregnation, thereby making it more uniform and stable. The gel polymer electrolyte can be cured.
겔 폴리머 전해질용 조성물을 경화하는 단계Curing the composition for gel polymer electrolyte
본 명세서에서, 상기 포메이션 단계 후에 겔 폴리머 전해질용 조성물을 경화 (겔화)하는 단계를 실시할 수 있다.In the present specification, a step of curing (gelling) the gel polymer electrolyte composition may be performed after the formation step.
상기 경화(겔화) 단계는 통상적인 열, e-빔, 감마선 조사에 의한 광경화 공정을 통해 실시할 수 있다. The curing (gelling) step may be carried out through a photocuring process by conventional heat, e-beam, gamma irradiation.
구체적으로, 상기 경화(겔화) 단계는 비활성 조건(inert condition)하에서 30℃ 내지 70℃, 구체적으로 40℃ 내지 65℃의 온도 범위에서 5시간 내지 24시간 동안 열 경화하여 실시할 수 있다.Specifically, the curing (gelling) step may be carried out by thermal curing for 5 hours to 24 hours in a temperature range of 30 ℃ to 70 ℃, specifically 40 ℃ to 65 ℃ under inert conditions (inert condition).
이와 같이 비활성 분위기하에서 경화 공정을 실시하게 되면, 라디칼 소멸제인 대기 중의 산소와 라디칼(radical)과의 반응이 근본적으로 차단되어 미반응 올리고머가 거의 존재하지 않을 정도로 중합반응 진척도(extent of reaction)를 증대시킬 수 있다. 따라서, 겔 전환율을 향상시킬 수 있고, 다량의 미반응 올리고머가 전지 내부에 잔존함으로써 야기되던 이차전지의 성능 저하를 방지할 수 있다. 상기 비활성 분위기 조건으로는 당 업계에 알려진 반응성이 낮은 기체를 사용할 수 있으며, 특히 질소, 아르곤, 헬륨 및 크세논으로 이루어진 군에서 선택된 1종 이상의 비활성 가스를 사용할 수 있다.Thus curing under inert atmosphere When the process is carried out, radical reaction between oxygen and radicals in the atmosphere, which is a radical quenching agent, is essentially blocked, thereby increasing the extent of reaction to the extent that unreacted oligomers are almost absent. Therefore, the gel conversion can be improved and the performance degradation of the secondary battery caused by the large amount of unreacted oligomer remaining inside the battery can be prevented. The inert atmosphere may be a gas having low reactivity known in the art, in particular one or more inert gases selected from the group consisting of nitrogen, argon, helium and xenon.
이러한 경화(겔화) 단계에 의해 상기 중합성 단량체가 서로 가교 결합되어 겔 형태의 폴리머 네트워크를 형성하고, 겔 폴리머 전해질용 조성물로부터 해리된 전해질 염이 상기 폴리머 네트워크 내에 균일하게 함침될 수 있다.By this curing (gelling) step, the polymerizable monomers may be crosslinked with each other to form a polymer network in a gel form, and electrolyte salts dissociated from the composition for gel polymer electrolyte may be uniformly impregnated in the polymer network.
또한, 본 발명의 방법에서는 상기 경화 단계 후, 25℃ 내지 70℃, 구체적으로 30℃ 내지 60℃ 조건하에서 1시간 내지 24시간 동안 에이징하는 단계를 추가로 포함할 수 있다. 상기 에이징 과정에서는 상기 충방전 및 경화 과정이 끝난 전지를 상온에서 일정 기간 동안 방치함으로써 추가적인 SEI 피막을 형성시킬 수 있고, 이로부터 추가적인 가스 발생을 유도할 수 있다.In addition, the method of the present invention may further comprise the step of aging for 1 hour to 24 hours under the curing step, 25 ℃ to 70 ℃, specifically 30 ℃ to 60 ℃ conditions. In the aging process, an additional SEI film may be formed by leaving the battery, which has been charged and discharged and cured, at a room temperature for a period of time, thereby inducing additional gas generation.
탈기하는 단계Degassing
또한, 본 발명의 명세서에서, 상기 겔 폴리머 전해질용 조성물을 경화하는 단계 이후에, 탈기하는 단계를 실시할 수 있다.In addition, in the specification of the present invention, after the step of curing the gel polymer electrolyte composition, it may be carried out a step of degassing.
상기 탈기 단계는 상기 전지 케이스에 압력을 가하면서 이루어질 수 있다. 상기 탈기 단계는 -85kPa 내지 -95kPa 압력으로 실시할 수 있다.The degassing step may be performed while applying pressure to the battery case. The degassing step can be carried out at a pressure of -85 kPa to -95 kPa.
그 다음, 상기 파우치형 케이스의 개봉된 영역을 120℃ 내지 150℃ 온도에서 약 2초 내지 5초 동안 실링할 수 있다.Then, the opened area of the pouch type case may be sealed at a temperature of 120 ° C. to 150 ° C. for about 2 seconds to 5 seconds.
전술한 바와 같이, 본 발명에서는 파우치형 이차전지 제조 시에 파우치형 예비 이차전지에 초음파 부재를 밀착 배치하고, 겔 폴리머 전해질용 조성물을 주액한 후, 또는 겔 폴리머 전해질용 조성물 주액과 동시에 초음파 진동과 압력을 동시에 가하여, 겔 폴리머 전해질용 조성물을 효과적으로 분산시켜 겔 폴리머 전해질용 조성물의 함침성을 향상시킬 수 있다. 그 결과, 파우치형 이차전지 제조 시에 웨팅(wetting) 시간 단축과 및 이에 따른 제조 비용을 절감할 수 있다. 따라서, 안정성 및 제반 성능이 향상된 파우치형 이차전지를 제조할 수 있다.As described above, in the present invention, the ultrasonic member is placed in close contact with the pouch-type secondary battery during manufacture of the pouch-type secondary battery, and the gel polymer electrolyte composition is injected, or simultaneously with the gel polymer electrolyte composition injection. By applying pressure simultaneously, the composition for gel polymer electrolyte can be effectively dispersed to improve the impregnation of the composition for gel polymer electrolyte. As a result, it is possible to shorten the wetting time in manufacturing the pouch type secondary battery and to thereby reduce the manufacturing cost. Therefore, a pouch type secondary battery having improved stability and overall performance can be manufactured.
이하, 본 발명을 구체적으로 설명하기 위해 실시예를 들어 상세하게 설명한다. 그러나 본 발명에 따른 실시예는 여러 가지 다른 형태로 변형될 수 있으며, 본 발명의 범위가 아래에서 상술하는 실시예에 한정되는 것으로 해석되어서는 안 된다. 본 발명의 실시예는 당업계에서 평균적인 지식을 가진 자에게 본 발명을 보다 완전하게 설명하기 위해서 제공되는 것이다.Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.
실시예Example
실시예 1.Example 1.
(겔 폴리머 전해질용 조성물 제조)(Manufacture of composition for gel polymer electrolyte)
1M LiPF6가 용해된 유기용매 (에틸렌카보네이트(EC):에틸메틸카보네이트(EMC)=3:7 부피비) 94.99g에 화학식 1a로 표시되는 화합물 5g 및 중합 개시제인 디메틸 2,2'-아조비스(2-메틸프로피오네이트) (CAS No. 2589-57-3) 0.01g을 첨가하여 겔 폴리머 전해질용 조성물을 제조하였다.Organic solvent in which 1M LiPF 6 was dissolved (ethylene carbonate (EC): ethyl methyl carbonate (EMC) = 3: 7 by volume) 5 g of the compound represented by the formula (1a) in 94.99 g and dimethyl 2,2'-azobis (polymerization initiator) ( 2-methylpropionate) (CAS No. 2589-57-3) was added to prepare a composition for a gel polymer electrolyte.
(파우치형 이차전지 제조)(Manufacture of pouch type secondary battery)
양극활물질로 LiCoO2, 도전재로 카본 블랙(carbon black) 및 바인더로 PVDF를 94:3:3 중량비로 용매인 N-메틸-2-피롤리돈(NMP)에 첨가하여 양극 혼합물 슬러리(고형분 함량 65 중량%)를 제조하였다. 상기 양극 혼합물 슬러리를 두께가 20㎛ 정도의 양극 집전체인 알루미늄(Al) 박막에 도포하고, 건조한 후, 롤 프레스(roll press)를 실시하여 양극을 제조하였다.LiCoO 2 as a positive electrode active material, carbon black as a conductive material, and PVDF as a binder were added to N-methyl-2-pyrrolidone (NMP) as a solvent in a 94: 3: 3 weight ratio to obtain a positive electrode mixture slurry (solid content). 65 wt%) was prepared. The positive electrode mixture slurry was applied to a thin film of aluminum (Al), which is a positive electrode current collector having a thickness of about 20 μm, and dried, followed by roll press to prepare a positive electrode.
이어서, 음극활물질로 탄소 분말, 바인더로 PVDF, 도전제로 카본 블랙(carbon black)을 96:3:1 중량비로 용매인 NMP에 첨가하여 음극 혼합물 슬러리(고형분 함량 75 중량%)를 제조하였다. 상기 음극 혼합물 슬러리를 두께가 10㎛의 음극 집전체인 구리(Cu) 박막에 도포하고, 건조한 후, 롤 프레스(roll press)를 실시하여 음극을 제조하였다.Subsequently, carbon powder as a negative electrode active material, PVDF as a binder, and carbon black as a conductive agent were added to NMP as a solvent in a weight ratio of 96: 3: 1 to prepare a negative electrode mixture slurry (solid content 75% by weight). The negative electrode mixture slurry was applied to a thin copper (Cu) thin film, which was a negative electrode current collector having a thickness of 10 μm, and dried, followed by roll press to prepare a negative electrode.
이어서, 상기 제조된 전극들 사이에 두께 20㎛의 폴리에틸렌(PE) 재질의 세퍼레이터를 개재하고 권취 및 압축하여 전극조립체를 제조한 다음, 이를 파우치형 전지 케이스에 삽입하여 파우치형 예비 이차전지를 제조하였다. Subsequently, an electrode assembly was manufactured by winding and compressing a separator having a thickness of 20 μm between polyethylene electrodes, and inserting the same into a pouch-type battery case, thereby preparing a pouch-type secondary battery. .
이어서, 상기 파우치형 예비 이차전지 양면에 파우치형 예비 이차전지 전면을 감싸는 알루미늄(Al)으로 이루어진 초음파 부재를 밀착하여 배치하였다.Subsequently, an ultrasonic member made of aluminum (Al) covering the entire surface of the pouch type preliminary secondary battery was disposed on both surfaces of the pouch type preliminary secondary battery.
초음파 부재 온도를 40℃로 유지하면서, 상기 제조된 겔 폴리머 전해질용 조성물을 주액하고, 140℃에서 겔 폴리머 전해질용 조성물 주입구를 밀봉하였다.While maintaining the ultrasonic member temperature at 40 ° C, the prepared composition for gel polymer electrolyte was injected, and the composition injection hole for the gel polymer electrolyte was sealed at 140 ° C.
이어서, 초음파 부재를 이용하여 파우치형 예비 이차전지 면적당 5 Kgf/㎠의 압력을 가압하는 동시에, 20 KHz의 초음파 진동을 100 사이클 (1 사이클: 5초 초음파 진동/5초 휴식기) 동안 가해 주었다.Subsequently, a pressure of 5 Kgf / cm &lt; 2 &gt; per pouch type preliminary secondary battery area was pressurized using an ultrasonic member, and ultrasonic vibration of 20 KHz was applied for 100 cycles (1 cycle: 5 seconds ultrasonic vibration / 5 seconds rest).
이어서, 0.1C에서 200mA로 3 시간 동안 포메이션 공정을 실시한 다음, 상온에서 2일 동안 에이징하고, 65℃에서 5 시간 경화 공정을 실시하여 겔 폴리머 전해질을 제조하였다.Subsequently, the formation process was performed for 3 hours at 200 mA at 0.1 C, then aged at room temperature for 2 days, and the curing process was performed at 65 ° C. for 5 hours to prepare a gel polymer electrolyte.
이어서, -85kPa 압력을 가하면서 탈기 단계를 실시하여 내부에서 발생한 가스를 제거하여 본 발명의 파우치형 이차전지를 제조하였다.Subsequently, a degassing step was performed while applying a -85 kPa pressure to remove the gas generated therein, thereby manufacturing the pouch type secondary battery of the present invention.
실시예 2.Example 2.
파우치형 이차전지 제조 시에 초음파 부재 온도를 40℃로 유지하면서, 겔 폴리머 전해질용 조성물을 주액하고, 140℃에서 겔 폴리머 전해질용 조성물 주입구를 밀봉하였다.The composition for gel polymer electrolyte was inject | poured, maintaining the ultrasonic member temperature at 40 degreeC at the time of manufacture of a pouch type secondary battery, and the composition injection port for gel polymer electrolyte was sealed at 140 degreeC.
이어서, 초음파 부재를 이용하여 파우치형 예비 이차전지 면적당 10 Kgf/㎠의 압력을 가압하는 동시에, 25 KHz의 초음파 진동을 100 사이클 (1 사이클: 5초 초음파 진동/5초 휴식기) 동안 가해주는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.Subsequently, the ultrasonic member is used to pressurize a pressure of 10 Kgf / cm2 per area of the pouch type preliminary secondary battery, and apply 25 KHz of ultrasonic vibration for 100 cycles (1 cycle: 5 seconds of ultrasonic vibration / 5 seconds of rest). Then, a pouch type secondary battery was manufactured in the same manner as in Example 1.
비교예 1.Comparative Example 1.
파우치형 이차전지 제조 시에, 상온 (25℃)에서 겔 폴리머 전해질용 조성물을 주액하고, 140℃에서 겔 폴리머 전해질용 조성물 주입구를 밀봉한 다음, 초음파 공정 및 가압 공정을 실시하지 않고, 포메이션 공정 및 경화 공정을 실시하는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.In the manufacture of the pouch type secondary battery, the composition for gel polymer electrolyte is injected at room temperature (25 ° C.), the composition injection hole for the gel polymer electrolyte is sealed at 140 ° C., and then the formation process and the ultrasonic wave process are not performed. A pouch type secondary battery was manufactured in the same manner as in Example 1, except that the curing step was performed.
비교예 2.Comparative Example 2.
파우치형 이차전지 제조 시에, 초음파 부재 온도를 40℃로 유지하면서, 겔 폴리머 전해질용 조성물을 주액하고, 140℃에서 겔 폴리머 전해질용 조성물 주입구를 밀봉한 다음, 초음파 공정 및 가입 공정을 실시하지 않고, 포메이션 공정 및 경화 공정을 실시하는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.During the manufacture of the pouch type secondary battery, the composition for gel polymer electrolyte was infused while maintaining the ultrasonic member temperature at 40 ° C., the composition injection hole for the gel polymer electrolyte was sealed at 140 ° C., and then the ultrasonic wave and the addition step were not performed. A pouch type secondary battery was manufactured in the same manner as in Example 1, except that the formation step and the curing step were performed.
비교예 3.Comparative Example 3.
파우치형 이차전지 제조 시에, 초음파 부재 온도를 40℃로 유지하면서, 겔 폴리머 전해질용 조성물을 주액하고, 140℃에서 겔 폴리머 전해질용 조성물 주입구를 밀봉하였다.At the time of manufacture of the pouch type secondary battery, the composition for gel polymer electrolyte was inject | poured, maintaining the ultrasonic member temperature at 40 degreeC, and the composition injection port for gel polymer electrolyte was sealed at 140 degreeC.
이어서, 초음파 부재를 이용하여 초음파 공정은 실시하지 않고, 파우치형 예비 이차전지에 면적당 5 Kgf/㎠의 압력을 가하는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.Subsequently, a pouch type secondary battery was manufactured in the same manner as in Example 1 except that an ultrasonic process was not performed using an ultrasonic member and a pressure of 5 Kgf / cm 2 per area was applied to the pouch type secondary battery.
비교예 4.Comparative Example 4.
파우치형 이차전지 제조 시에, 초음파 부재 온도를 상온 (25℃)으로 유지하는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.In manufacturing a pouch type secondary battery, a pouch type secondary battery was manufactured in the same manner as in Example 1 except that the ultrasonic member temperature was maintained at room temperature (25 ° C).
비교예 5.Comparative Example 5.
파우치형 이차전지 제조 시에, 초음파 부재 온도를 상온 (25℃)으로 유지하는 것을 제외하고는 상기 실시예 2와 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.In manufacturing the pouch type secondary battery, a pouch type secondary battery was manufactured in the same manner as in Example 2 except that the ultrasonic member temperature was maintained at room temperature (25 ° C).
비교예 6.Comparative Example 6.
파우치형 이차전지 제조 시에, 초음파 부재 온도를 40℃로 유지하면서, 겔 폴리머 전해질용 조성물을 주액한 후, 초음파 부재를 이용하여 가압하지 않고, 20 KHz의 초음파 진동을 100 사이클 (1 사이클: 5초 초음파 진동/5초 휴식기) 동안 가해 주는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.In the manufacture of the pouch type secondary battery, after injecting the composition for the gel polymer electrolyte while maintaining the ultrasonic member temperature at 40 ° C., the ultrasonic vibration at 20 KHz was performed 100 cycles (1 cycle: 5) without pressurization using the ultrasonic member. Pouch-type secondary battery was manufactured in the same manner as in Example 1, except that the ultrasonic wave was subjected to ultrasonic vibration / 5 second rest period).
비교예 7.Comparative Example 7.
파우치형 이차전지 제조 시에, 초음파 부재 온도를 100℃로 유지하는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.In manufacturing the pouch type secondary battery, a pouch type secondary battery was manufactured in the same manner as in Example 1 except that the ultrasonic member temperature was maintained at 100 ° C.
비교예 8.Comparative Example 8.
파우치형 이차전지 제조 시에, 초음파 부재 온도는 상온(25℃)을 유지하면서, 가압 시 초음파 부재를 이용하여 파우치형 예비 이차전지 면적당 3,500 Kgf/㎠의 압력으로 가압하는 것을 제외하고는 상기 실시예 1과 마찬가지의 방법으로 파우치형 이차전지를 제조하였다.In manufacturing the pouch type secondary battery, the ultrasonic member temperature is maintained at room temperature (25 ° C.), except for pressurizing at a pressure of 3,500 Kgf / cm2 per area of the pouch type preliminary secondary battery using the ultrasonic member during pressurization. A pouch type secondary battery was manufactured in the same manner as in 1.
초음파 부재 온도 (℃)Ultrasonic Member Temperature (℃) 가압 압력(Kgf/㎠)Pressurized Pressure (Kgf / ㎠) 초음파 인가여부Whether ultrasound is applied 초음파 진동 (KHz)Ultrasonic Vibration (KHz)
실시예 1Example 1 4040 55 OO 2020
실시예 2Example 2 4040 1010 OO 2525
비교예 1Comparative Example 1 2525 ×× ×× ××
비교예 2Comparative Example 2 4040 ×× ×× ××
비교예 3Comparative Example 3 4040 55 ×× ××
비교예 4Comparative Example 4 2525 55 OO 2020
비교예 5Comparative Example 5 2525 1010 OO 2525
비교예 6Comparative Example 6 4040 ×× OO 2020
비교예 7Comparative Example 7 100100 55 OO 2020
비교예 8Comparative Example 8 2525 3,5003,500 O O 2525
실험예Experimental Example
실험예 1. Experimental Example 1 .
25℃에서 교류 임피던스 측정법을 사용하여 상기 실시예 1 및 비교예 1에서 각각 제조된 겔 폴리머 전해질을 포함하는 파우치형 이차전지의 함침성을 측정하였다. 이때, 이온전도도는 VMP3 측정 장비와 4294A를 사용하여 주파수 대역 0.05Hz 내지 100MHz에서 측정하였다. 그 결과를 하기 도 2에 나타내었다. 이때, 도 2에서 가로축은 임피던스 연산부에서 산출된 임피던스(Z)의 실수값(Zre)을 나타내고, 세로축은 임피던스의 허수값(Zim)을 나타낸다. Impregnation of the pouch-type secondary battery including the gel polymer electrolytes prepared in Example 1 and Comparative Example 1 was measured using AC impedance measurement at 25 ° C. At this time, the ion conductivity was measured in the frequency band 0.05Hz to 100MHz using VMP3 measuring equipment and 4294A. The results are shown in FIG. 2. 2, the horizontal axis represents a real value Z re of the impedance Z calculated by the impedance calculator, and the vertical axis represents an imaginary value Z im of impedance.
또한, 도 2에서 참고예는 상기 실시예 1에서 겔 폴리머 전해질용 조성물 주액 직후 측정한 교류 임피던스를 나타낸 것이다.In addition, the reference example in Figure 2 shows the AC impedance measured immediately after the injection of the composition for the gel polymer electrolyte in Example 1.
일반적으로 겔 폴리머 전해질용 조성물의 함침성이 향상되면, 전지 내부 공극(pore)에 겔 폴리머 전해질용 조성물이 미함침되는 경우가 적어지기 때문에 저항이 감소한다. 따라서, 교류 임피던스를 측정하면 벌크(bulk) 저항이 작게 측정되며, 함침이 진행되면 될수록 저항 값이 일정하게 수렴된다.In general, when the impregnability of the composition for a gel polymer electrolyte is improved, the resistance decreases because the composition for the gel polymer electrolyte is less impregnated with the pore inside the battery. Therefore, when the AC impedance is measured, the bulk resistance is measured to be small, and the resistance value converges as the impregnation proceeds.
도 2를 살펴보면, 참고예의 파우치형 이차전지 값을 기준으로 하여 초음파 진동을 가해주는 단계를 실시한 실시예 1의 파우치형 이차전지가 초음파 진동을 가해주는 단계를 실시하지 않은 비교예 1의 파우치형 이차전지보다 벌크 저항 값의 현저히 감소된 것을 알 수 있다. 2, the pouch type secondary battery of Comparative Example 1, in which the pouch type secondary battery of Example 1, which performed the step of applying ultrasonic vibration based on the value of the pouch type secondary battery of the reference example, was not subjected to the step of applying the ultrasonic vibration. It can be seen that the bulk resistance value is significantly reduced than the battery.
이러한 결과로부터 겔 폴리머 전해질용 조성물 주입 시에 초음파 진동을 가해주는 단계를 실시하는 경우, 전지내에서 겔 폴리머 전해질용 조성물의 함침성이 향상되는 것을 알 수 있다.From these results, it can be seen that the impregnation of the gel polymer electrolyte composition in the battery is improved when the step of applying ultrasonic vibration when the gel polymer electrolyte composition is injected.
실험예 2. 초기 용량 평가Experimental Example 2 Initial Capacity Evaluation
실시예 1 및 2에서 제조된 파우치형 리튬 이차전지와 비교예 1 내지 8에서 제조된 파우치형 리튬 이차전지 각각에 대하여, CC-CV(constant current-constant voltage) 방식으로 0.3C의 속도(rate)로 333mA의 전류에서 전지의 전압이 4.2V가 될 때까지 정전류(CC) 충전하고, 전지의 전압이 4.2V가 된 후에 4.2V의 정전압(CV)을 유지하면서 0.05C 속도의 전류에서 컷오프(cut-off) 하여 1회 충전하였다. 1회째의 충전을 행한 전지에 대하여 0.3C의 속도로 333mA의 정전류에서 전지 전압이 3V에 이를 때까지 정전류(CC) 방전을 행하는 1 사이클을 3회 반복하고, 3번째 방전 용량을 초기용량으로 선정하였다. 그 결과를 하기 표 2 나타내었다.For each of the pouch-type lithium secondary batteries prepared in Examples 1 and 2 and the pouch-type lithium secondary batteries prepared in Comparative Examples 1 to 8, the rate of 0.3 C in the constant current-constant voltage (CC-CV) method At a current of 333mA to charge a constant current (CC) until the battery's voltage reaches 4.2V, and after the battery's voltage reaches 4.2V, it cuts off at a current of 0.05C while maintaining the constant voltage (CV) of 4.2V. -off) and charged once. The first charged battery was repeated three times in one cycle of constant current (CC) discharge at a constant current of 333 mA at a rate of 0.3 C until the battery voltage reached 3 V, and the third discharge capacity was selected as the initial capacity. It was. The results are shown in Table 2 below.
초기 용량 (mAh)Initial capacity (mAh)
실시예 1Example 1 995995
실시예 2Example 2 10001000
비교예 1Comparative Example 1 980980
비교예 2Comparative Example 2 982982
비교예 3Comparative Example 3 985985
비교예 4Comparative Example 4 985985
비교예 5Comparative Example 5 986986
비교예 6Comparative Example 6 983983
비교예 7Comparative Example 7 921921
비교예 8Comparative Example 8 953953
표 2를 살펴보면, 실시예 1 및 2의 리튬 이차전지의 경우 전해질 함침성이 우수하기 때문에, 비교예 1 내지 8에서 제조된 파우치형 이차전지에 비해 더 높은 초기 용량을 발현하는 것을 알 수 있다.Looking at Table 2, it can be seen that the lithium secondary batteries of Examples 1 and 2 have a higher initial capacity than the pouch type secondary batteries prepared in Comparative Examples 1 to 8 because of excellent electrolyte impregnation.
실험예 3. 초기 저항 값 평가Experimental Example 3. Evaluation of Initial Resistance Value
실시예 1 및 2에서 제조된 파우치형 리튬 이차전지와 비교예 1 내지 8에서 제조된 파우치형 리튬 이차전지 각각에 대하여, CC-CV(constant current-constant voltage) 방식으로 0.3C의 속도(rate)로 333mA의 전류에서 전지의 전압이 4.2V가 될 때까지 정전류(CC) 충전하고, 전지의 전압이 4.2V가 된 후에 4.2V의 정전압(CV)을 유지하면서 0.05C 속도의 전류에서 컷오프(cut-off) 하여 1회 충전하였다. 1회째의 충전을 행한 전지에 대하여 0.3C의 속도로 333mA의 정전류에서 전지 전압이 3V에 이를 때까지 정전류(CC) 방전을 행하는 1 사이클을 3회 반복하고, 2A (2 C)의 전류로 10초 방전을 진행할 때 발생하는 전압 강하를 기록한 다음, R=V/I (옴의 법칙)을 이용하여 산출한 초기 평가시 측정되는 DC 방전 저항값을 하기 표 3에 나타내었다. 이때, DC 저항은 이차전지의 출력 특성과 밀접한 관계를 맺는다.For each of the pouch-type lithium secondary batteries prepared in Examples 1 and 2 and the pouch-type lithium secondary batteries prepared in Comparative Examples 1 to 8, the rate of 0.3 C in the constant current-constant voltage (CC-CV) method At a current of 333mA to charge a constant current (CC) until the battery's voltage reaches 4.2V, and after the battery's voltage reaches 4.2V, it cuts off at a current of 0.05C while maintaining the constant voltage (CV) of 4.2V. -off) and charged once. The first charged battery was repeated three times in a cycle of performing constant current (CC) discharge at a constant current of 333 mA at a rate of 0.3 C until the battery voltage reached 3 V, and a current of 2 A (2 C) was 10 times. After recording the voltage drop generated during the super discharge, the DC discharge resistance value measured at the initial evaluation calculated using R = V / I (ohm law) is shown in Table 3 below. At this time, the DC resistance has a close relationship with the output characteristics of the secondary battery.
저항 (mΩ)Resistance (mΩ)
실시예 1Example 1 3131
실시예 2Example 2 3030
비교예 1Comparative Example 1 3838
비교예 2Comparative Example 2 3737
비교예 3Comparative Example 3 3737
비교예 4Comparative Example 4 3737
비교예 5Comparative Example 5 3636
비교예 6Comparative Example 6 3737
비교예 7Comparative Example 7 5252
비교예 8Comparative Example 8 4747
상기 표 3을 살펴보면, 실시예 1 및 2에서 제조된 파우치형 이차전지의 경우, 전해질 함침성이 증가하고 이에 따라 균일한 전극-전해질 반응을 야기하기 때문에, 비교예 1 내지 8에서 제조된 파우치형 이차전지에 비해 내부 저항값이 낮은 것을 알 수 있다.Referring to Table 3, in the case of the pouch type secondary batteries prepared in Examples 1 and 2, since the electrolyte impregnation increases and thus causes a uniform electrode-electrolyte reaction, the pouch type prepared in Comparative Examples 1 to 8 It can be seen that the internal resistance is lower than that of the secondary battery.

Claims (10)

  1. 파우치형 케이스의 내부 공간에 전극조립체를 수납하여 파우치형 예비(preliminary) 전지를 제조하는 단계;Manufacturing a pouch type preliminary battery by accommodating an electrode assembly in an inner space of the pouch type case;
    파우치형 예비 이차전지의 양면에 금속 소재의 초음파 부재를 밀착하여 배치하는 단계;Disposing the ultrasonic member made of a metal material on both sides of the pouch type secondary battery;
    상기 파우치형 예비 이차전지 내부에 겔 폴리머 전해질용 조성물을 주입하는 단계;Injecting a gel polymer electrolyte composition into the pouch-type preliminary secondary battery;
    상기 초음파 부재를 이용하여 상기 파우치형 예비 이차전지를 가압하면서 파우치형 예비 이차전지에 초음파 진동을 가해주는 단계;Applying ultrasonic vibration to the pouch type secondary battery while pressurizing the pouch type secondary battery using the ultrasonic member;
    상기 파우치형 예비 이차전지를 포메이션하는 단계; Forming the pouch type secondary battery;
    상기 겔 폴리머 전해질용 조성물을 경화하는 단계; 및Curing the gel polymer electrolyte composition; And
    탈기하는 단계;를 포함하며,Degassing; comprising;
    상기 초음파 부재는 30℃ 내지 80℃의 온도를 유지하고,The ultrasonic member maintains a temperature of 30 ℃ to 80 ℃,
    상기 파우치형 예비 이차전지를 가압하는 단계는 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 내지 3,000 kgf/㎠ 압력을 가하면서 실시하는 것인 파우치형 이차전지의 제조방법.Pressing the pouch-type preliminary secondary battery is a method of manufacturing a pouch-type secondary battery is carried out while applying a pressure of 0.1 Kgf / ㎠ to 3,000 kgf / ㎠ per pouch-type secondary battery.
  2. 청구항 1에 있어서,The method according to claim 1,
    상기 초음파 부재는 스테인레스, 철, 알루미늄, 구리, 니켈 및 이들의 2종 이상의 합금으로 이루어진 군으로부터 선택된 금속 소재로 이루어진 것인 파우치형 이차전지의 제조방법.The ultrasonic member is a method of manufacturing a pouch type secondary battery that is made of a metal material selected from the group consisting of stainless steel, iron, aluminum, copper, nickel and two or more alloys thereof.
  3. 청구항 1에 있어서,The method according to claim 1,
    상기 초음파 부재는 스테인레스 또는 알루미늄으로 이루어진 것인 파우치형 이차전지의 제조방법.The ultrasonic member is a method of manufacturing a pouch type secondary battery that is made of stainless or aluminum.
  4. 청구항 1에 있어서,The method according to claim 1,
    상기 초음파 부재는 파우치형 예비 이차전지의 전면을 감싸는 구조로 형성된 것인 파우치형 이차전지의 제조방법.The ultrasonic member is a method of manufacturing a pouch type secondary battery that is formed in a structure surrounding the front of the pouch type secondary battery.
  5. 청구항 1에 있어서,The method according to claim 1,
    상기 초음파 부재는 30℃ 내지 60℃의 온도를 유지하는 것인 파우치형 이차전지의 제조방법.The ultrasonic member is a method of manufacturing a pouch type secondary battery that maintains a temperature of 30 ℃ to 60 ℃.
  6. 청구항 1에 있어서,The method according to claim 1,
    상기 파우치형 예비 이차전지를 가압하는 단계는 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 내지 500 kgf/㎠ 압력을 가하면서 실시하는 것인 파우치형 이차전지의 제조방법.Pressing the pouch-type secondary battery is a method of manufacturing a pouch-type secondary battery is carried out while applying a pressure of 0.1 kgf / cm 2 to 500 kgf / cm 2 per pouch type secondary battery.
  7. 청구항 1에 있어서,The method according to claim 1,
    상기 파우치형 예비 이차전지를 가압하는 단계는 파우치형 예비 이차전지 면적당 0.1 Kgf/㎠ 내지 100 kgf/㎠ 압력을 가하면서 실시하는 것인 파우치형 이차전지의 제조방법.Pressing the pouch-type preliminary secondary battery is a method of manufacturing a pouch-type secondary battery is carried out while applying a pressure of 0.1 kgf / cm 2 to 100 kgf / cm 2 per pouch type secondary battery.
  8. 청구항 1에 있어서,The method according to claim 1,
    상기 초음파 진동을 가해주는 단계는 20kHz 내지 200 MHz의 진동수를 가지는 진동을 인가하여 실시하는 것인 파우치형 이차전지의 제조방법.The applying of the ultrasonic vibration is a method of manufacturing a pouch type secondary battery that is performed by applying a vibration having a frequency of 20kHz to 200MHz.
  9. 청구항 1에 있어서,The method according to claim 1,
    상기 초음파 진동을 가해주는 단계는 상기 겔 폴리머 전해질용 조성물을 주입하는 단계와 동시에 수행되는 것인 파우치형 이차전지의 제조 방법.Wherein the step of applying the ultrasonic vibration is a method of manufacturing a pouch type secondary battery that is carried out simultaneously with the step of injecting the gel polymer electrolyte composition.
  10. 청구항 1에 있어서,The method according to claim 1,
    상기 포메이션하는 단계 후 및 겔 폴리머 전해질용 조성물을 경화하는 단계 전에 초음파 진동을 가해주는 단계를 추가로 포함하는 것인 파우치형 이차전지의 제조 방법.Method of producing a pouch type secondary battery further comprises the step of applying ultrasonic vibration after the step of forming and before the step of curing the composition for gel polymer electrolyte.
PCT/KR2019/003403 2018-03-26 2019-03-22 Method of manufacturing pouch-type secondary battery WO2019190128A1 (en)

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