WO2018048166A1 - Electrode comprising electrode current collector of three-dimensional network structure - Google Patents

Electrode comprising electrode current collector of three-dimensional network structure Download PDF

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Publication number
WO2018048166A1
WO2018048166A1 PCT/KR2017/009672 KR2017009672W WO2018048166A1 WO 2018048166 A1 WO2018048166 A1 WO 2018048166A1 KR 2017009672 W KR2017009672 W KR 2017009672W WO 2018048166 A1 WO2018048166 A1 WO 2018048166A1
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WIPO (PCT)
Prior art keywords
electrode
current collector
unit
secondary battery
dimensional network
Prior art date
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PCT/KR2017/009672
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French (fr)
Korean (ko)
Inventor
목은경
유민규
엄인성
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.)
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Priority claimed from KR1020170112505A external-priority patent/KR102098154B1/en
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to JP2018547249A priority Critical patent/JP6723370B2/en
Priority to EP17849050.4A priority patent/EP3370281A4/en
Priority to US15/774,192 priority patent/US20180337408A1/en
Priority to CN201780004251.9A priority patent/CN108292736B/en
Publication of WO2018048166A1 publication Critical patent/WO2018048166A1/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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/72—Grids
    • H01M4/74—Meshes or woven material; Expanded metal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to an electrode including a current collector of a three-dimensional network structure.
  • lithium secondary batteries have high energy density and operating potential, have long cycle life, and have low self discharge rate. Is commercially available and widely used.
  • Electrodes are manufactured through a heat treatment process after applying a slurry in which an electrode active material, a binder, and a conductive material are appropriately mixed on a cathode / cathode current collector. That is, the electrode mixture layer including the binder and the conductive material is formed on the positive electrode / cathode current collector.
  • the binder included in the electrode mixture layer is relatively light, so that it is not evenly dispersed in the electrode mixture layer, and the surface is lifted up. This is because the thicker the electrode mixture layer is, the more severe the separation is. Deterioration of cycle characteristics and lifespan of the battery due to separation of the current collector and the active material due to the volume change generated are inevitable.
  • the present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.
  • unit electrodes having an electrode mixture including an electrode active material are introduced into pores of a unit current collector having a three-dimensional network structure.
  • the present invention was completed.
  • the present invention provides a secondary battery electrode, wherein two or more unit electrodes are stacked in close contact with each other, and adjacent unit electrodes are electrically connected to each other via an electrode mixture. And an electrode mixture containing an electrode active material is introduced into a gap of a unit current collector having a three-dimensional network structure.
  • the electrode may have a structure in which two to ten unit electrodes are stacked.
  • the unit current collector having the three-dimensional network structure may be a conductive metal felt.
  • the average thickness of the unit current collector having the three-dimensional network structure is 30 ⁇ m to 400 ⁇ m.
  • the average diameter of the unit current collector pores having the three-dimensional network structure is 1 ⁇ m to 100 ⁇ m.
  • the unit electrode is a mixture of the unit current collector and the electrode mixture having a three-dimensional network structure.
  • the thickness of the electrode coalescence layer coated on one outer surface of the unit current collector is 10 ⁇ m to 100 ⁇ m.
  • the thickness of the electrode is 50 ⁇ m to 500 ⁇ m.
  • the unit electrodes are joined to each other by a binder in the electrode mixture.
  • a general current collector is additionally interposed between the unit electrodes.
  • the present invention provides a battery cell comprising the secondary battery electrode.
  • the secondary battery electrode includes the steps of: (a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure; (b) coating the electrode slurry on a unit current collector; (c) drying the electrode slurry to form an electrode mixture layer; (d) rolling unit electrodes; And (e) stacking unit electrodes; It may be prepared by a method for manufacturing a secondary battery electrode, characterized in that it comprises a.
  • the secondary battery electrode includes the steps of: (a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure; (b) coating the electrode slurry on a unit current collector; (c) drying the electrode slurry to form an electrode mixture layer; (d) stacking unit electrodes; And (e) rolling the stacked unit electrodes; It may be prepared by a method for manufacturing a secondary battery electrode, characterized in that it comprises a.
  • unit electrodes having a structure in which an electrode mixture is impregnated and coated are laminated on a unit current collector having a three-dimensional network structure, and the unit electrodes are formed through the electrode mixture. It is a connected structure.
  • the structure in which the electrode mixture including the electrode active material is moved into the pores formed in the unit current collector so that the inside of the unit current collector is filled with the electrode mixture can alleviate an increase in the overall electrode thickness.
  • a high capacity battery can be provided.
  • the electrode mixture including the electrode active material is filled in the inside of the current collector, and ultimately, the binder may be uniformly dispersed in the electrode, thereby preventing desorption of the electrode active material, thereby improving the performance of the electrode and extending the life.
  • FIG. 1 is a perspective view schematically showing a unit current collector according to an embodiment of the present invention
  • FIG. 2 is a perspective view schematically showing an electrode in which a unit current collector of FIG. 1 is stacked;
  • FIG. 3 is an enlarged perspective view showing an electrode mixture introduced into the pores of a unit current collector by enlarging a portion of FIG. 2;
  • FIG. 4 is a perspective view schematically showing a state in which an electrode mixture is coated on the unit current collector of FIG. 1;
  • FIG. 6 is a vertical cut plane of an electrode in which the unit current collectors of FIG. 4 are stacked.
  • the present invention is a secondary battery electrode, two or more unit electrodes are stacked in close contact with each other, mutually adjacent unit electrodes are electrically connected via an electrode mixture, each unit electrode is a three-dimensional network structure It is an electrode for secondary batteries characterized by introducing the electrode mixture containing an electrode active material into the space
  • FIG. 1 schematically illustrates a perspective view of a unit current collector according to an embodiment of the present invention
  • FIG. 2 schematically illustrates a perspective view of an electrode in which the unit current collectors of FIG. 1 are stacked.
  • the unit electrode 10 is composed of a unit current collector 11 having a three-dimensional network structure having pores 13, and the pores 13 are formed of the unit current collector. It is composed of open pores penetrating the outer surface and the inside, and the electrode mixture including the electrode active material penetrates between the pores.
  • the electrode for the secondary battery of the present invention since the electrode for the secondary battery of the present invention has a structure in which open pores are formed in the unit current collector itself, when the electrode mixture is coated on the unit current collector, the electrode mixture including the electrode active material flows between the open pores. . Therefore, the electrode mixture including the electrode active material is not only coated on the unit current collector, but also fills pores in the current collector, so that even when the same amount of the electrode mixture is loaded, the electrode mixture is formed on the current collector only.
  • the increase in thickness can be prevented and the increase in internal resistance can be prevented because the distance between the outermost surface of the electrode mixture layer and the surface of the current collector does not increase.
  • the electrode mixture layer containing the electrode active material penetrates into the unit current collector, adhesion between the current collector and the electrode active material is increased, and the electrode mixture containing the electrode active material is filled in the current collector so that the binder is uniformly dispersed in the electrode. Since the electrode active material is prevented from being detached during repeated charging and discharging, the electrode performance is improved and the life is extended, and the impregnation rate of the electrolyte is reduced due to the formation of a thick mixture layer. .
  • the secondary battery electrode according to the present invention has a structure in which the unit electrodes are electrically connected to each other via an electrode mixture with adjacent unit electrodes in a stacked state.
  • the electrode may have a structure in which two to ten unit electrodes are stacked.
  • the electrode may have a structure in which four to ten unit electrodes are stacked.
  • the electrode 100 of the present invention is formed by stacking a plurality of unit electrodes 10, and 2 to 10 unit current collectors having an average thickness (a) of 30 ⁇ m to 400 ⁇ m are formed. The thickness of the entire electrode is laminated to form 50 to 500 ⁇ m.
  • the unit current collector may be formed thicker than the thickness of a general current collector.
  • the average thickness of the unit current collector may be 30 ⁇ m to 400 ⁇ m, preferably 30 ⁇ m to 350 ⁇ m, and more preferably 40 ⁇ m to 300 ⁇ m.
  • the average thickness of the unit current collector is thinner than 30 ⁇ m, the strength of the current collector is significantly lowered. If the average thickness of the unit current collector is larger than 400 ⁇ m, the electrode mixture layer is difficult to penetrate into the current collector, which is not preferable. .
  • the unit current collector is preferably made of a material having high electrical conductivity.
  • the unit current collector may be made of a conductive metal felt having a three-dimensional network structure. Since the electrode of the present invention uses a conductive metal felt as a current collector, the flexibility of the metal felt itself also makes it suitable for use in a flexible battery.
  • the material having high electrical conductivity is not particularly limited as long as it does not have a chemical effect by reacting with the electrode mixture, and for example, aluminum (Al), magnesium (Mg), iron (Fe), nickel (Ni), and chromium. (Cr), copper (Cu), stainless steel (Stainless Steel) or one or more selected from the group consisting of alloys thereof, and may vary in detail depending on the potential of the electrode and the composition of the electrode mixture.
  • the aspect ratio of the metal fibers constituting the conductive metal felt may be in the range of 10 to 1,000, more preferably 10 to 500, most preferably 30 to 150.
  • the pores 13 formed in the unit current collector 11 may be formed in various sizes, and may be 1 ⁇ m to 100 ⁇ m, more preferably in consideration of particle diameters of the electrode active material, the conductive agent, and the binder included in the electrode mixture.
  • the average diameter of the pores may be formed in the range of 10 ⁇ m to 90 ⁇ m, most preferably 20 ⁇ m to 80 ⁇ m.
  • the average diameter of the open pores is smaller than 1 ⁇ m, since the electrode mixture having a larger particle size is less likely to move inside the pores, the particle size range of the applicable electrode active material may be limited. It is not preferable because there is a problem that the strength of the current collector is weakened.
  • the open pores may have a structure in which an electrode mixture including an electrode active material is introduced, and the electrode mixture may be rolled after coating the electrode slurry on the unit current collector to induce introduction of the electrode mixture into the pores. Process may be included.
  • the viscosity of the electrode mixture falls within a predetermined range.
  • the viscosity of the electrode mixture may be selected in consideration of the size and coating method of the open pores formed in the current collector in the range of 2,000 cP or more to 12,000 cP or less.
  • an electrode mixture having a high viscosity may be used.
  • a low viscosity electrode mixture is used. It is preferable.
  • the extra electrode mixture not introduced into the open pores formed in the current collector may form a coating layer in a state that is applied to one side or both sides of the unit current collector.
  • FIG. 4 schematically illustrates a perspective view of a unit electrode coated with an electrode mixture on the unit current collector of FIG. 1, and FIG. 5 schematically illustrates a vertical cut plane along the line AA ′ of FIG. 4.
  • the unit current collector 201 is coated with the electrode mixture 202, and the viscosity of the electrode mixture may be selected within the range of viscosity 2,000 cP to 12,000 cP according to the coating method.
  • the electrode mixture 202 is introduced into at least some of the pores 203.
  • the coating amount of the electrode mixture is larger than the amount that can be introduced into the open pores formed in the current collector, the extra electrode mixture not introduced into the pores will form the electrode mixture layer 204 on the outer surface of the current collector. .
  • the thickness d of the electrode mixture layer may be uniformly formed.
  • the thickness of the electrode coalescence layer coated on one outer surface of the unit current collector may be 10 ⁇ m to 100 ⁇ m, and more preferably 10 ⁇ m to 80 ⁇ m.
  • the bonding force between adjacent unit electrodes may be weak, and when the thickness of the electrode mixture layer is thicker than 100 ⁇ m, the electrolyte impregnation rate may be low. The problem of inferior mobility of lithium transfer may occur, which is not preferable.
  • a plurality of unit electrodes formed by coating an electrode mixture on an electrode current collector having open pores formed thereon are laminated to form one electrode, and the thickness of the electrode is coated on the outer surface of the current collector to the thickness of the electrode current collector.
  • the thickness of the electrode may be freely set to have a desired capacity in consideration of the thickness of the electrode mixture layer, and the thickness of the electrode may be 50 ⁇ m to 500 ⁇ m, more preferably 100 ⁇ m to 500 ⁇ m, and most Preferably from 200 ⁇ m to 450 ⁇ m.
  • the thickness of the electrode is smaller than 50 ⁇ m, it is difficult to achieve the purpose of providing a high capacity battery, and when the electrode is larger than 500 ⁇ m, when the number of stacked unit electrodes increases, when rolling after lamination or secondary battery It is not preferable because the phenomenon that the electrode is inclined or pushed to one side may occur at the time of use.
  • the electrode 300 is formed by stacking five unit electrodes 310, 320, 330, 340, and 350 in close contact with each other. It is electrically connected via.
  • the unit electrodes may have a structure in which the unit electrodes are bonded to each other by a binder in the electrode mixture, and due to the presence of the binder, the electrode mixture and the unit The bonding force between the collectors can also be increased.
  • a general current collector having no porous structure may be interposed in various shapes between the unit electrodes to be stacked. At least one current collector may be interposed in one electrode.
  • an anode may be an aluminum current collector
  • a cathode may be a copper foil current collector.
  • the electrode 300 can roll the unit electrode in order to reduce the thickness of the unit electrode by introducing the electrode mixture into the pores inside the current collector, the method of stacking the individual unit electrodes after rolling May be used, and the unit electrodes may be rolled in a state of stacking the unit electrodes without individually rolling the unit electrodes.
  • the present invention provides a battery cell having a structure in which at least one of the positive electrode or the negative electrode including the secondary battery electrode and the electrolyte is formed in the cell case, and the electrolyte flows into the open pores of the unit current collector from the secondary battery electrode. Since the electrode mixture introduced into the open pores of the unit current collector may be impregnated in the electrolyte, the capacity may be prevented from being reduced.
  • the present invention also provides a method for manufacturing the above secondary battery electrode
  • It provides a method of manufacturing a secondary battery electrode comprising a.
  • the electrode for secondary batteries coats the electrode slurry on the unit current collector having a porous structure
  • the electrode slurry may move to pores inside the unit current collector to fill the electrode slurry inside the unit current collector.
  • the electrode slurry since the electrode slurry is dried and the unit electrodes are rolled in the state in which the electrode slurry is filled in the current collector, the thickness of the unit electrodes may be uniformly formed.
  • the present invention is a manufacturing method of the electrode for secondary batteries
  • It provides a method of manufacturing a secondary battery electrode comprising a.
  • the electrode for secondary batteries coats the electrode slurry on the unit current collector having a porous structure
  • the electrode slurry may move to the pores of the unit current collector to fill the electrode slurry inside the unit current collector.
  • the electrode slurry is dried while the electrode slurry is filled in the unit current collector, the unit electrodes on which the electrode mixture layer is formed are stacked, and the stacked unit electrodes are rolled.
  • the present invention also provides a lithium secondary battery comprising the electrode.
  • the lithium secondary battery may be composed of the positive electrode, the negative electrode, the separator and the lithium salt-containing non-aqueous electrolyte, and is prepared by putting the electrolyte into a porous separator between the positive electrode and the negative electrode in a conventional manner known in the art. Can be.
  • the electrode according to the present invention may be one or more selected from the positive electrode or the negative electrode. That is, both the positive electrode and / or the negative electrode may have an electrode structure according to the present invention, and only one electrode of the positive electrode and the negative electrode may have the electrode structure according to the present invention and is not particularly limited and may be appropriately selected as necessary. Can be.
  • the positive electrode may be prepared by, for example, applying a slurry of a mixture of a positive electrode active material, a conductive material, and a binder onto a unit current collector having a three-dimensional network structure according to the present invention, followed by drying. More may be added.
  • the conductive material is typically added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material.
  • a conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon blacks such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.
  • the binder is a component that assists the bonding of the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material.
  • binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.
  • the filler is optionally used as a component for inhibiting expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical change in the battery.
  • the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.
  • the negative electrode may be prepared by, for example, applying a slurry of a mixture of a negative electrode active material, a conductive material, and a binder onto a unit current collector having a three-dimensional network structure according to the present invention, followed by drying. More may be added.
  • the negative electrode active material may be, for example, carbon such as hardly graphitized carbon or graphite carbon; Li x Fe 2 O 3 (0 ⁇ x ⁇ 1), Li x WO 2 (0 ⁇ x ⁇ 1), Sn x Me 1 - x Me ' y O z (Me: Mn, Fe, Pb, Ge; Me' Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen, 0 ⁇ x ⁇ 1; 1 ⁇ y ⁇ 3; 1 ⁇ z ⁇ 8); Lithium metal; Lithium alloys; Silicon-based alloys; Tin-based alloys; SnO, SnO 2 , PbO, PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 5 , GeO, GeO 2 , Bi 2 O 3 , Bi 2 O 4 , and metal oxides such as Bi 2
  • the positive electrode according to the present invention is a positive electrode, and contains a lithium transition metal oxide generally used as a positive electrode active material
  • the positive electrode has a loading amount of 700 mg / 25 cm 2
  • the electrode is a negative electrode and includes a carbon material generally used as a negative electrode active material
  • the loading amount of the negative electrode may be up to 300 mg / 25 cm 2 or more.
  • the separator is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used.
  • the pore diameter of the separator is generally from 0.01 to 10 ⁇ m ⁇ m, thickness is generally 5 ⁇ 300 ⁇ m.
  • a separator for example, olefin polymers such as chemical resistance and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fibers or polyethylene are used.
  • a solid electrolyte such as a polymer
  • the solid electrolyte may also serve as a separator.
  • the lithium salt-containing nonaqueous electrolyte is composed of a nonaqueous electrolyte and lithium.
  • a nonaqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte and the like are used as the nonaqueous electrolyte, but are not limited thereto.
  • non-aqueous organic solvent examples include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and gamma Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxorone, formamide, dimethylformamide, dioxolon , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxy methane, dioxorone derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl pyroionate and ethyl propionate can be
  • organic solid electrolyte examples include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyedgetion lysine, polyester sulfides, polyvinyl alcohols, polyvinylidene fluorides, Polymerizers containing ionic dissociating groups and the like can be used.
  • Examples of the inorganic solid electrolyte include Li 3 N, LiI, Li 5 NI 2 , Li 3 N-LiI-LiOH, LiSiO 4 , LiSiO 4 -LiI-LiOH, Li 2 SiS 3 , Li 4 SiO 4 , Nitrides, halides, sulfates and the like of Li, such as Li 4 SiO 4 -LiI-LiOH, Li 3 PO 4 -Li 2 S-SiS 2 , and the like, may be used.
  • the lithium salt is a good material to be dissolved in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide.
  • pyridine triethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphate triamide, nitro Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride and the like may be added. .
  • a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included, and carbon dioxide gas may be further included to improve high temperature storage characteristics, and FEC (Fluoro-Ethylene) may be further included. Carbonate), PRS (Propene sultone) may be further included.
  • lithium salts such as LiPF 6 , LiClO 4 , LiBF 4 , LiN (SO 2 CF 3 ) 2, and the like, may be prepared by cyclic carbonate of EC or PC, which is a highly dielectric solvent, and DEC, DMC, or EMC, which are low viscosity solvents.
  • Lithium salt-containing non-aqueous electrolytes can be prepared by adding them to a mixed solvent of linear carbonates.
  • the present invention also provides a secondary battery in which an electrode assembly composed of the electrode for secondary batteries is sealed inside the battery case together with an electrolyte, and the secondary battery may be used in a battery cell used as a power source for a small device.
  • a battery pack including a plurality of battery cells used as a power source for medium and large devices requiring high temperature stability, long cycle characteristics, high rate characteristics, and the like may be preferably used as a unit battery in a device including the battery pack as a power source. Can be.
  • the device specifically includes a power tool that is powered by a mobile electronic device, a battery-based motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; It may be any one selected from the system for power storage, but is not limited thereto.
  • Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like
  • Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters)
  • Electric golf carts It may be any one selected from the system for power storage, but is not limited thereto.
  • Cathode active material LiNi 0 . 55 Mn 0 . 30 Co 0 . 15 O 2 , Denka black as a conductive material , and polyvinylidene fluoride (polyvinylidene fluoride) as a binder were mixed in a weight ratio of 96: 2: 2, and NMP (N-methyl pyrrolidone) was added to prepare a slurry.
  • the slurry was coated on aluminum felt having an average diameter of pores of 20 ⁇ m, an aspect ratio of 100, and a thickness of 40 ⁇ m to obtain a unit anode. After drying the unit positive electrode in a vacuum oven at 120 °C, laminated two dried unit positive electrode and rolled to prepare a positive electrode. At this time, the thickness of the electrode including the current collector was 75 ⁇ m.
  • Lithium metal 40 ⁇ m was attached to copper (Cu) foil as a counter electrode, and a polyolefin separator was interposed between the positive electrode and the counter electrode, followed by ethylene carbonate (EC) and ethyl methyl carbonate (DEC).
  • EC ethylene carbonate
  • DEC ethyl methyl carbonate
  • P-type half cell was prepared by injecting an electrolyte solution in which 1 M lithium hexafluorophosphate (LiPF 6 ) was dissolved in a solvent mixed at a volume ratio of 50:50.
  • a lithium secondary battery was manufactured in the same manner as in Example 1, except that the average diameter of the current collector pores was changed as shown in Table 1.
  • a lithium secondary battery was manufactured in the same manner as in Example 1, except that the thickness of the aluminum felt was changed to 55 ⁇ m and the thickness of the electrode including the current collector was adjusted to 102 ⁇ m.
  • a lithium secondary battery was manufactured in the same manner as in Example 5, except that the average diameter of the current collector pores was changed as shown in Table 1.
  • Cathode active material LiNi 0 . 55 Mn 0 . 30 Co 0 . 15 O 2 , Denka black as a conductive material , and polyvinylidene fluoride (polyvinylidene fluoride) as a binder were mixed in a weight ratio of 96: 2: 2, and NMP (N-methyl pyrrolidone) was added to prepare a slurry.
  • the positive electrode slurry was applied in three layers between the two aluminum and the outer surface, and dried in a vacuum oven at 120 ° C. to prepare a positive electrode. At this time, the thickness of the electrode was 75 ⁇ m including the thickness of the current collector, the thickness of the current collector is 12 micrometers.
  • Lithium metal 40 ⁇ m was attached to copper (Cu) foil as a counter electrode, and a polyolefin separator was interposed between the positive electrode and the counter electrode, followed by ethylene carbonate (EC) and ethyl methyl carbonate (DEC).
  • EC ethylene carbonate
  • DEC ethyl methyl carbonate
  • P-type half cell was prepared by injecting an electrolyte solution in which 1 M lithium hexafluorophosphate (LiPF 6 ) was dissolved in a solvent mixed at a volume ratio of 50:50.
  • a lithium secondary battery was manufactured in the same manner as in Comparative Example 1, except that the thickness of the electrode including the current collector was changed as in Table 1.
  • the batteries prepared in Examples and Comparative Examples were carried out under conditions of 1 / 3C to 1 / 3C (one time charge and discharge) between 4.2V and 2.5V.
  • the lifetime characteristics were evaluated from the discharge capacity retention rate, and the discharge capacity retention rate was expressed as a percentage of the initial capacity after the charge and discharge was repeated 200 times. The results are shown in Table 1.
  • Example 1 20 75 3.431 3.163 92.2 Example 2 30 75 3.864 3.578 92.6 Example 3 50 75 3.715 3.444 92.7 Example 4 80 75 3.449 3.197 92.7 Example 5 20 102 3.313 2.932 88.5 Example 6 30 102 3.753 3.318 88.4 Example 7 50 102 3.623 3.224 89.0 Example 8 80 102 3.330 2.957 88.8 Comparative Example 1 - 75 3.643 3.356 92.1 Comparative Example 2 - 102 3.446 2.939 85.3
  • Examples 1 to 4 and Comparative Example 1 even though the thickness of the electrode is the same as the electrode of the battery of Examples 1 to 4 compared to the battery of Comparative Example 1 or even better, it can be seen that better. .
  • Examples 5 to 8 and Comparative Example 2 is a high-loading electrode having the same electrode thickness, Comparative Example 2 has a much lower life characteristics, while Examples 5 to 8 is confirmed to maintain excellent life characteristics compared to Comparative Example 2 do.
  • the electrode of the present invention shortens the reaction distance due to the decrease in the physical distance between the electrode current collector and the active material compared to the electrode of the comparative example, thereby reducing the resistance in the electrode, and the role of the support that the three-dimensional network structure supports the active material layer. It is believed that this is because the possibility of detachment of the active material layer and the current collector in the electrode is reduced.

Abstract

The present invention relates to an electrode for a secondary battery, in which two or more unit electrodes are stacked in a state of close contact with each other, wherein the unit electrodes adjacent to each other are electrically connected via an electrode mixture, in which each unit electrode is configured such that the electrode mixture containing an electrode active material is introduced into a pore of a unit current collector having a three-dimensional network structure.

Description

3차원 망상 구조의 전극집전체를 포함하는 전극Electrode including an electrode current collector of a three-dimensional network structure
본 발명은 3차원 망상 구조의 집전체를 포함하는 전극에 대한 것이다.The present invention relates to an electrode including a current collector of a three-dimensional network structure.
모바일 기기에 대한 기술 개발과 수요가 증가함에 따라 에너지원으로서 이차전지의 수요가 급격히 증가하고 있고, 그러한 이차전지 중 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 is rapidly increasing as a source of energy. Among them, lithium secondary batteries have high energy density and operating potential, have long cycle life, and have low self discharge rate. Is commercially available and widely used.
또한, 환경문제에 대한 관심이 커짐에 따라 대기오염의 주요 원인의 하나인 가솔린 차량, 디젤 차량 등 화석연료를 사용하는 차량을 대체할 수 있는 전기자동차, 하이브리드 전기자동차에 대한 연구가 많이 진행되고 있다. 이러한 전기자동차, 하이브리드 전기자동차 등의 동력원으로는, 높은 에너지 밀도와 방전 전압의 리튬 이차전지를 사용하는 연구 및 이의 상용화에 대한 관심이 증가하고 있다.In addition, as interest in environmental problems grows, research on electric vehicles and hybrid electric vehicles that can replace vehicles using fossil fuel, such as gasoline and diesel vehicles, which are one of the main causes of air pollution, is being conducted. . As a power source of such an electric vehicle, a hybrid electric vehicle, there is an increasing interest in research and commercialization thereof using a lithium secondary battery of high energy density and discharge voltage.
또한, 다기능 소형화의 웨어러블 디바이스(wearable device) 및 휴대용 기기의 개발 추세에 따라 이차전지 자체의 소형화 및 박형화에 대한 필요성이 커지고 있으며, 장시간 사용이 가능하도록 하기 위하여 이차전지의 용량을 증가시키기 위한 노력이 다각도로 이루어지고 있다.In addition, according to the development trend of wearable devices and portable devices of multifunctional miniaturization, the need for miniaturization and thinning of the secondary battery itself is increasing, and efforts to increase the capacity of the secondary battery in order to enable long-term use have been made. It is done in various angles.
종래의 전극은 전극 활물질, 바인더 및 도전재가 적절히 혼합된 슬러리를 양극/음극 집전체 위에 도포한 후 열처리 공정을 통해 제조된다. 즉, 양극/음극 집전체 위에 바인더 및 도전재를 포함하는 전극 합제층이 형성된 구조이다.Conventional electrodes are manufactured through a heat treatment process after applying a slurry in which an electrode active material, a binder, and a conductive material are appropriately mixed on a cathode / cathode current collector. That is, the electrode mixture layer including the binder and the conductive material is formed on the positive electrode / cathode current collector.
이러한 구조에 있어서, 전지의 용량을 높이기 위하여 전극 합제층의 두께를 증가시키게 되면, 집전체와 활물질 상층부의 거리가 증가함에 따라 활물질 상층부에서 발생되는 전자가 빠르게 집전체로 이동하지 못하게 되고, 전극 내 발생하는 리튬 이온 역시, 이동 경로가 길어짐에 따라 이동 속도에 제한이 생기므로 전체적인 전극 내 저항이 크게 증가한다. 또한, 두께 증가는 활물질 층에 대한 전해액의 함침율을 감소시킬 수 있기 때문에 전극 저항 증가의 문제는 더욱 커질 수 있다. In this structure, when the thickness of the electrode mixture layer is increased in order to increase the capacity of the battery, as the distance between the current collector and the upper portion of the active material increases, electrons generated in the upper portion of the active material do not quickly move to the current collector, and the inside of the electrode The generated lithium ions also have a limitation in the moving speed as the moving path becomes longer, which greatly increases the overall electrode resistance. In addition, since the increase in thickness can reduce the impregnation rate of the electrolyte solution on the active material layer, the problem of increasing the electrode resistance can be further increased.
뿐만 아니라, 전극 합제층에 포함되는 바인더는 상대적으로 가벼워 전극 합제층에 고르게 분산되지 않고, 표면에 들뜨는 현상이 발생하는데, 이는 전극 합제층이 두꺼울수록 그 분리가 심하므로 전지의 충/방전 과정에서 발생되는 부피변화에 따른 집전체와 활물질의 분리에 의한 전지의 사이클 특성 저하 및 수명 저하를 피할 수 없다. In addition, the binder included in the electrode mixture layer is relatively light, so that it is not evenly dispersed in the electrode mixture layer, and the surface is lifted up. This is because the thicker the electrode mixture layer is, the more severe the separation is. Deterioration of cycle characteristics and lifespan of the battery due to separation of the current collector and the active material due to the volume change generated are inevitable.
이러한 문제점들을 해결하기 위해서, 종래에는 공극률, 전극 활물질의 종류 등을 다양하게 한 전극 합제 층을 다층으로 코팅하는 등의 기술이 개발되어 왔다. 그러나, 이러한 구조 역시 로딩량에는 한계가 있을 뿐만 아니라 소망하는 정도의 전자전도도 및 이온전도도를 얻을 수 없었고, 전극 합제 층의 두께 증가는 전극 강도가 감소하는 기능성의 문제를 갖고 있는 동시에, 미래에 요구되는 이차전지의 소형화 및 박형화에 대한 한계를 극복하지 못한다. In order to solve these problems, a technique such as coating an electrode mixture layer having various porosities, types of electrode active materials, and the like in multiple layers has been developed. However, such a structure also has a limitation in loading amount, and it is not possible to obtain a desired degree of electron and ion conductivity, and increasing the thickness of the electrode mixture layer has a problem of functionality in which the electrode strength decreases, and is required in the future. It does not overcome the limitation on miniaturization and thinning of secondary batteries.
따라서, 에너지 밀도가 향상된 고로딩 전극을 제조하기 위해서, 상기 문제점들을 해결할 수 있는 새로운 구조의 전극 기술에 대한 필요성이 높은 실정이다. Therefore, there is a high demand for a new structure of electrode technology that can solve the above problems in order to manufacture a high loading electrode having improved energy density.
본 발명은 상기와 같은 종래기술의 문제점과 과거로부터 요청되어온 기술적 과제를 해결하는 것을 목적으로 한다.The present invention aims to solve the problems of the prior art as described above and the technical problems that have been requested from the past.
본 출원의 발명자들은 심도 있는 연구와 다양한 실험을 거듭한 끝에, 이후 설명하는 바와 같이, 3차원 망상형 구조를 가진 단위 집전체의 기공에 전극 활물질을 포함한 전극 합제가 도입된 구조의 단위 전극들로 이루어진 이차전지용 전극을 사용하는 경우, 전극 합제의 로딩량이 증가하더라도 전극 내부의 저항이 작아지고 전극 합제층의 탈리를 방지할 수 있음을 확인하고 본 발명을 완성하기에 이르렀다.The inventors of the present application have conducted extensive research and various experiments, and as described later, unit electrodes having an electrode mixture including an electrode active material are introduced into pores of a unit current collector having a three-dimensional network structure. In the case of using the secondary battery electrode made, it was confirmed that even if the loading amount of the electrode mixture was increased, the resistance inside the electrode was reduced and the detachment of the electrode mixture layer was prevented, and thus the present invention was completed.
이러한 목적을 달성하기 위한 본 발명은, 이차전지용 전극으로서, 둘 이상의 단위 전극들이 상호 밀착된 상태로 적층되어 있고, 상호 인접한 단위 전극들은 전극 합제를 경유하여 전기적으로 연결되어 있으며, 각각의 단위 전극은, 3차원 망상형 구조를 가지는 단위 집전체의 공극에 전극 활물질을 포함하는 전극 합제가 도입되어 있는 것을 특징으로 하는 이차전지용 전극이다. In order to achieve the above object, the present invention provides a secondary battery electrode, wherein two or more unit electrodes are stacked in close contact with each other, and adjacent unit electrodes are electrically connected to each other via an electrode mixture. And an electrode mixture containing an electrode active material is introduced into a gap of a unit current collector having a three-dimensional network structure.
본 발명의 적절한 일 실시예에 의하면, 상기 전극은 2개 내지 10개의 단위 전극들이 적층된 구조로 이루어질 수 있다. According to a suitable embodiment of the present invention, the electrode may have a structure in which two to ten unit electrodes are stacked.
본 발명의 적절한 일 실시예에 의하면, 상기 3차원 망상형 구조를 가지는 단위 집전체는 도전성 금속 펠트일 수 있다.According to a suitable embodiment of the present invention, the unit current collector having the three-dimensional network structure may be a conductive metal felt.
본 발명의 적절한 일 실시예에 의하면, 상기 3차원 망상형 구조를 가지는 단위 집전체의 평균 두께는 30 ㎛ 내지 400 ㎛이다. According to a suitable embodiment of the present invention, the average thickness of the unit current collector having the three-dimensional network structure is 30 ㎛ to 400 ㎛.
본 발명의 적절한 일 실시예에 의하면, 상기 3차원 망상형 구조를 가지는 단위 집전체 기공들의 평균 직경은 1 ㎛ 내지 100 ㎛이다.According to a suitable embodiment of the present invention, the average diameter of the unit current collector pores having the three-dimensional network structure is 1 ㎛ to 100 ㎛.
본 발명의 적절한 일 실시예에 의하면, 상기 단위 전극은 3차원 망상형 구조를 가지는 단위 집전체와 전극 합제가 혼재되어 있다. According to a preferred embodiment of the present invention, the unit electrode is a mixture of the unit current collector and the electrode mixture having a three-dimensional network structure.
본 발명의 적절한 일 실시예에 의하면, 상기 단위 집전체의 일측 외면에 코팅되어 있는 전극 합체층의 두께는 10 ㎛ 내지 100 ㎛이다.According to a suitable embodiment of the present invention, the thickness of the electrode coalescence layer coated on one outer surface of the unit current collector is 10 ㎛ to 100 ㎛.
본 발명의 적절한 일 실시예에 의하면, 상기 전극의 두께는 50 ㎛ 내지 500 ㎛이다. According to a suitable embodiment of the present invention, the thickness of the electrode is 50 ㎛ to 500 ㎛.
본 발명의 적절한 일 실시예에 의하면, 상기 단위 전극들은 전극 합제 중의 바인더에 의해 상호 접합되어 있다.According to a suitable embodiment of the present invention, the unit electrodes are joined to each other by a binder in the electrode mixture.
본 발명의 적절한 일 실시예에 의하면, 상기 단위 전극들 사이에는 일반 집전체가 추가적으로 개재되어 있다. According to a suitable embodiment of the present invention, a general current collector is additionally interposed between the unit electrodes.
본 발명은 상기 이차전지용 전극으로 이루어진 것을 특징으로 하는 전지셀을 제공한다.The present invention provides a battery cell comprising the secondary battery electrode.
본 발명의 적절한 일 실시예에 의하면 상기한 이차전지용 전극은 (a) 3차원 망상형 구조의 단위 집전체 및 전극 슬러리를 준비하는 과정; (b) 전극 슬러리를 단위 집전체에 코팅하는 과정; (c) 전극 슬러리를 건조하여 전극 합제층을 형성하는 과정; (d) 단위 전극들을 압연하는 과정; 및 (e) 단위 전극들을 적층하는 과정; 을 포함하는 것을 특징으로 하는 이차전지용 전극의 제조방법에 의해 제조될 수 있다. According to a suitable embodiment of the present invention, the secondary battery electrode includes the steps of: (a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure; (b) coating the electrode slurry on a unit current collector; (c) drying the electrode slurry to form an electrode mixture layer; (d) rolling unit electrodes; And (e) stacking unit electrodes; It may be prepared by a method for manufacturing a secondary battery electrode, characterized in that it comprises a.
본 발명의 적절한 일 실시예에 의하면 상기한 이차전지용 전극은 (a) 3차원 망상형 구조의 단위 집전체 및 전극 슬러리를 준비하는 과정; (b) 전극 슬러리를 단위 집전체에 코팅하는 과정; (c) 전극 슬러리를 건조하여 전극 합제층을 형성하는 과정; (d) 단위 전극들을 적층하는 과정; 및 (e) 적층된 단위 전극들을 압연하는 과정; 을 포함하는 것을 특징으로 하는 이차전지용 전극의 제조방법에 의해 제조될 수 있다.According to a suitable embodiment of the present invention, the secondary battery electrode includes the steps of: (a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure; (b) coating the electrode slurry on a unit current collector; (c) drying the electrode slurry to form an electrode mixture layer; (d) stacking unit electrodes; And (e) rolling the stacked unit electrodes; It may be prepared by a method for manufacturing a secondary battery electrode, characterized in that it comprises a.
이상에서 설명한 바와 같이, 본 발명에 따른 이차전지용 전극은 3차원 망상형 구조를 가지는 단위 집전체에 전극 합제가 함침 및 코팅된 구조의 단위 전극들이 적층되어 있고, 상기 단위 전극들은 전극 합제를 경유하여 연결되어 있는 구조이다. 이와 같이, 상기 단위 집전체에 형성된 기공 내부로 전극 활물질을 포함하는 전극 합제가 이동하여 단위 집전체 내부가 전극 합제로 채워지게 되는 구조는, 전체적인 전극 두께의 증가를 완화할 수 있고, 집전체와 전극 활물질의 물리적인 거리를 단축하게 되므로, 전극 합제의 로딩량이 증가하더라도 리튬 이온의 이동 경로가 길어짐에 따른 내부 저항 증가를 방지할 수 있으며, 동일한 두께의 일반적인 집전체를 사용하는 경우와 비교할 때, 고용량의 전지를 제공할 수 있다.As described above, in the secondary battery electrode according to the present invention, unit electrodes having a structure in which an electrode mixture is impregnated and coated are laminated on a unit current collector having a three-dimensional network structure, and the unit electrodes are formed through the electrode mixture. It is a connected structure. As such, the structure in which the electrode mixture including the electrode active material is moved into the pores formed in the unit current collector so that the inside of the unit current collector is filled with the electrode mixture can alleviate an increase in the overall electrode thickness. Since the physical distance of the electrode active material is shortened, even if the loading amount of the electrode mixture is increased, it is possible to prevent an increase in internal resistance due to a long movement path of the lithium ions, and when compared to the case of using a common current collector having the same thickness, A high capacity battery can be provided.
또한, 전극 합제의 로딩량이 증가하더라도 집전체와 전극 활물질 간의 거리가 짧아 고출력 및 고용량의 구현이 모두 가능하다. In addition, even if the loading amount of the electrode mixture is increased, the distance between the current collector and the electrode active material is short, so that both high output and high capacity can be realized.
또한, 집전체의 내부에 전극 활물질을 포함하는 전극 합제가 채워져 궁극적으로 전극 내에 바인더가 고르게 분산될 수 있어 전극 활물질의 탈리 현상을 방지함으로써 전극의 성능이 향상되고 수명이 연장되는 효과도 있다. In addition, the electrode mixture including the electrode active material is filled in the inside of the current collector, and ultimately, the binder may be uniformly dispersed in the electrode, thereby preventing desorption of the electrode active material, thereby improving the performance of the electrode and extending the life.
뿐만 아니라, 집전체로 도전성 금속 펠트를 사용함으로써, 금속 펠트 자체가 갖는 유연성으로 인해 플렉서블 전지에 사용되기 적합한 이점도 있다.In addition, by using the conductive metal felt as a current collector, there is an advantage suitable for use in the flexible battery due to the flexibility of the metal felt itself.
도 1은 본 발명의 하나의 실시예에 따른 단위 집전체를 모식적으로 나타낸 사시도이다;1 is a perspective view schematically showing a unit current collector according to an embodiment of the present invention;
도 2는 도 1의 단위 집전체가 적층된 전극을 모식적으로 나타낸 사시도이다;FIG. 2 is a perspective view schematically showing an electrode in which a unit current collector of FIG. 1 is stacked;
도 3는 도 2의 일부분을 확대한 것으로 단위 집전체의 기공 내부에 전극 합제가 도입된 것을 나타낸 사시도이다; 3 is an enlarged perspective view showing an electrode mixture introduced into the pores of a unit current collector by enlarging a portion of FIG. 2;
도 4는 도 1의 단위 집전체에 전극 합제가 코팅된 상태를 모식적으로 나타낸 사시도이다;4 is a perspective view schematically showing a state in which an electrode mixture is coated on the unit current collector of FIG. 1;
도 5는 도 4의 A-A'에 따른 수직 절단면이다; 및5 is a vertical cut plane according to AA ′ in FIG. 4; And
도 6은 도 4의 단위 집전체들이 적층된 전극의 수직 절단면이다.6 is a vertical cut plane of an electrode in which the unit current collectors of FIG. 4 are stacked.
본 발명은, 이차전지용 전극으로서, 둘 이상의 단위 전극들이 상호 밀착된 상태로 적층되어 있고, 상호 인접한 단위 전극들은 전극 합제를 경유하여 전기적으로 연결되어 있으며, 각각의 단위 전극은, 3차원 망상형 구조를 가지는 단위 집전체의 공극에 전극 활물질을 포함하는 전극 합제가 도입되어 있는 것을 특징으로 하는 이차전지용 전극이다. The present invention is a secondary battery electrode, two or more unit electrodes are stacked in close contact with each other, mutually adjacent unit electrodes are electrically connected via an electrode mixture, each unit electrode is a three-dimensional network structure It is an electrode for secondary batteries characterized by introducing the electrode mixture containing an electrode active material into the space | gap of the unit electrical power collector which has a.
도 1은 본 발명의 하나의 실시예에 따른 단위 집전체의 사시도를 모식적으로 도시하고 있으며, 도 2는 도 1의 단위 집전체들이 적층된 전극의 사시도를 모식적으로 도시하고 있다.1 schematically illustrates a perspective view of a unit current collector according to an embodiment of the present invention, and FIG. 2 schematically illustrates a perspective view of an electrode in which the unit current collectors of FIG. 1 are stacked.
도 1, 도 2 및 도 3을 참조하면, 단위 전극(10)은 기공들(13)을 가진 3차원 망상 구조의 단위 집전체(11)로 이루어져 있고, 기공들(13)은 단위 집전체의 외면과 내부를 관통하는 개방형 기공들로 이루어져 있으며, 전극 활물질을 포함하는 전극 합제가 기공들 사이 사이에 침투되어 있다. 1, 2 and 3, the unit electrode 10 is composed of a unit current collector 11 having a three-dimensional network structure having pores 13, and the pores 13 are formed of the unit current collector. It is composed of open pores penetrating the outer surface and the inside, and the electrode mixture including the electrode active material penetrates between the pores.
이와 같이, 본 발명의 이차전지용 전극은 단위 집전체 자체에 개방형 기공들이 형성된 구조이기 때문에, 상기 단위 집전체 상에 전극 합제를 코팅하는 경우 전극 활물질을 포함하는 전극 합제가 개방형 기공들 사이로 흘러 들어가게 된다. 따라서, 전극 활물질을 포함하는 전극 합제는 단위 집전체 상에 코팅될 뿐 아니라 집전체 내부 기공을 채우게 되는 바, 동일한 양의 전극 합제를 로딩하더라도 집전체 상에만 코팅층이 형성되는 전극에 비하여 전체적인 전극의 두께 증가를 방지할 수 있고, 전극 합제층의 최외곽과 집전체 표면 간의 거리가 증가하지 않기 때문에 내부 저항이 증가하는 것을 방지할 수 있는 것이다.As described above, since the electrode for the secondary battery of the present invention has a structure in which open pores are formed in the unit current collector itself, when the electrode mixture is coated on the unit current collector, the electrode mixture including the electrode active material flows between the open pores. . Therefore, the electrode mixture including the electrode active material is not only coated on the unit current collector, but also fills pores in the current collector, so that even when the same amount of the electrode mixture is loaded, the electrode mixture is formed on the current collector only. The increase in thickness can be prevented and the increase in internal resistance can be prevented because the distance between the outermost surface of the electrode mixture layer and the surface of the current collector does not increase.
또한, 단위 집전체 내부까지 전극 활물질을 포함하는 전극 합제층이 침투하기 때문에 집전체와 전극 활물질의 밀착력이 증가하고, 집전체의 내부에 전극 활물질을 포함하는 전극 합제가 채워져 전극 내에 바인더가 고르게 분산될 수 있어 반복적인 충방전시 전극 활물질이 탈리되는 것을 방지해 전극의 성능이 향상되고 수명이 연장되는 효과가 있으며, 두꺼운 합제층의 형성으로 인해 전해액의 함침율이 감소하는 문제를 방지할 수 있다.In addition, since the electrode mixture layer containing the electrode active material penetrates into the unit current collector, adhesion between the current collector and the electrode active material is increased, and the electrode mixture containing the electrode active material is filled in the current collector so that the binder is uniformly dispersed in the electrode. Since the electrode active material is prevented from being detached during repeated charging and discharging, the electrode performance is improved and the life is extended, and the impregnation rate of the electrolyte is reduced due to the formation of a thick mixture layer. .
본 발명에 따른 이차전지용 전극은, 상기 단위 전극들이 적층된 상태에서 인접한 단위 전극들과 전극 합제를 경유하여 전기적으로 연결된 구조이며, 전극 합제를 코팅하더라도 전극의 두께 증가 폭이 적은 편인 바, 고용량의 이차전지를 제공하기 위하여 상기 전극은 2개 내지 10개의 단위 전극들이 적층된 구조로 이루어질 수 있으며, 바람직하게는 4개 내지 10개의 단위 전극들이 적층된 구조로 이루어질 수 있다.The secondary battery electrode according to the present invention has a structure in which the unit electrodes are electrically connected to each other via an electrode mixture with adjacent unit electrodes in a stacked state. In order to provide a secondary battery, the electrode may have a structure in which two to ten unit electrodes are stacked. Preferably, the electrode may have a structure in which four to ten unit electrodes are stacked.
도 2를 참조하면, 본 발명의 전극(100)은 복수의 단위 전극들(10)이 적층되어 형성되는 바, 평균 두께(a)가 30 ㎛ 내지 400 ㎛인 단위 집전체들이 2개 내지 10개가 적층되어 전체적인 전극의 두께는 50 ㎛ 내지 500 ㎛로 형성된다. Referring to FIG. 2, the electrode 100 of the present invention is formed by stacking a plurality of unit electrodes 10, and 2 to 10 unit current collectors having an average thickness (a) of 30 μm to 400 μm are formed. The thickness of the entire electrode is laminated to form 50 to 500 ㎛.
하나의 구체적인 예에서, 상기 단위 집전체는 개방형 기공들이 형성된 구조인 점을 고려할 때, 강도가 약한 문제가 발생할 수 있는 바, 일반적인 집전체의 두께보다 두껍게 형성될 수 있다. 예를 들어, 상기 단위 집전체의 평균 두께는 30 ㎛ 내지 400 ㎛일 수 있으며, 바람직하게는 30 ㎛ 내지 350 ㎛일 수 있고 더욱 바람직하게는 40 ㎛ 내지 300 ㎛일 수 있다.In one specific example, considering that the unit current collector has a structure in which open pores are formed, a problem of weak strength may occur, and thus, the unit current collector may be formed thicker than the thickness of a general current collector. For example, the average thickness of the unit current collector may be 30 μm to 400 μm, preferably 30 μm to 350 μm, and more preferably 40 μm to 300 μm.
상기 단위 집전체의 평균 두께가 30 ㎛보다 얇은 경우에는, 집전체의 강도가 현저히 낮아지는 문제가 있고, 400 ㎛보다 두꺼운 경우에는 전극 합제층이 집전체 내부까지 침투하기 어려운 문제가 있으므로 바람직하지 않다.If the average thickness of the unit current collector is thinner than 30 μm, the strength of the current collector is significantly lowered. If the average thickness of the unit current collector is larger than 400 μm, the electrode mixture layer is difficult to penetrate into the current collector, which is not preferable. .
상기 단위 집전체는 전기 전도도가 높은 소재로 이루어지는 것이 바람직한 바, 예를 들어, 3차원 네트워크 구조를 가지는 도전성 금속 펠트로 이루어질 수 있다. 본 발명의 전극은 집전체로써 도전성 금속 펠트를 사용하기 때문에, 금속 펠트 자체가 갖는 유연성으로 인해 플렉서블 전지에 사용되기 적합한 이점도 있게 된다.The unit current collector is preferably made of a material having high electrical conductivity. For example, the unit current collector may be made of a conductive metal felt having a three-dimensional network structure. Since the electrode of the present invention uses a conductive metal felt as a current collector, the flexibility of the metal felt itself also makes it suitable for use in a flexible battery.
상기 전기 전도도가 높은 소재는, 전극 합제와 반응하여 화학적인 영향을 주는 것이 아니라면 특별히 제한되지 않으며, 예를 들어, 알루미늄(Al), 마그네슘(Mg), 철(Fe), 니켈(Ni), 크롬(Cr), 구리(Cu), 스테인리스 스틸(Stainless Steel) 또는 이들의 합금으로 이루어진 군에서 선택되는 1종 이상일 수 있으며, 상세하게는 전극의 전위와 전극 합제의 구성 성분에 따라 달라질 수 있다.The material having high electrical conductivity is not particularly limited as long as it does not have a chemical effect by reacting with the electrode mixture, and for example, aluminum (Al), magnesium (Mg), iron (Fe), nickel (Ni), and chromium. (Cr), copper (Cu), stainless steel (Stainless Steel) or one or more selected from the group consisting of alloys thereof, and may vary in detail depending on the potential of the electrode and the composition of the electrode mixture.
상기 도전성 금속 펠트를 구성하는 금속 섬유의 종횡비(aspect ratio)는 10 내지 1,000의 범위일 수 있고, 더욱 바람직하게는 10 내지 500, 가장 바람직하게는 30 내지 150 이다. The aspect ratio of the metal fibers constituting the conductive metal felt may be in the range of 10 to 1,000, more preferably 10 to 500, most preferably 30 to 150.
단위 집전체(11)에 형성된 기공(13)의 크기는 매우 다양하게 형성되어 있는 바, 전극 합제에 포함된 전극 활물질, 도전제 및 바인더 등의 입경을 고려하여 1 ㎛ 내지 100 ㎛, 더욱 바람직하게는 10 ㎛ 내지 90 ㎛, 가장 바람직하게는 20 ㎛ 내지 80㎛의 범위에서 기공의 평균 직경이 형성될 수 있다.The pores 13 formed in the unit current collector 11 may be formed in various sizes, and may be 1 μm to 100 μm, more preferably in consideration of particle diameters of the electrode active material, the conductive agent, and the binder included in the electrode mixture. The average diameter of the pores may be formed in the range of 10 μm to 90 μm, most preferably 20 μm to 80 μm.
상기 개방형 기공들의 평균 직경이 1 ㎛ 보다 작은 경우에는, 이보다 크기가 큰 입경을 갖는 전극 합제가 기공 내부로 이동하기 어렵기 때문에 적용 가능한 전극 활물질의 입경 범위가 제한될 수 있으며, 100 ㎛ 보다 큰 경우에는 집전체의 강도가 약해지는 문제가 있으므로 바람직하지 않다.When the average diameter of the open pores is smaller than 1 μm, since the electrode mixture having a larger particle size is less likely to move inside the pores, the particle size range of the applicable electrode active material may be limited. It is not preferable because there is a problem that the strength of the current collector is weakened.
또한, 상기 개방형 기공들의 적어도 일부에는 전극 활물질을 포함하는 전극 합제가 도입되어 있는 구조일 수 있는 바, 전극 합제가 기공들에 도입되는 것을 유도하기 위하여 단위 집전체에 전극 슬러리를 코팅한 후 압연하는 과정이 포함될 수 있다.In addition, at least some of the open pores may have a structure in which an electrode mixture including an electrode active material is introduced, and the electrode mixture may be rolled after coating the electrode slurry on the unit current collector to induce introduction of the electrode mixture into the pores. Process may be included.
이와 같이, 상기 3차원 망상 구조의 단위 집전체에 전극 합제를 코팅하는 경우, 전극 합제가 이동하여 단위 집전체의 기공들에 도입되기 위하여, 상기 전극 합제의 점도는 일정한 범위 내에 해당하는 것이 적절한 바, 예를 들어, 상기 전극 합제의 점도는 2,000 cP 이상 내지 12,000 cP 이하의 범위에서 집전체에 형성된 개방형 기공의 크기 및 코팅 방법 등을 고려하여 선택될 수 있다.As such, when the electrode mixture is coated on the unit current collector of the three-dimensional network structure, in order for the electrode mixture to move and be introduced into the pores of the unit current collector, it is appropriate that the viscosity of the electrode mixture falls within a predetermined range. For example, the viscosity of the electrode mixture may be selected in consideration of the size and coating method of the open pores formed in the current collector in the range of 2,000 cP or more to 12,000 cP or less.
구체적으로, 압력을 인가하는 방법을 포함한 코팅법을 이용하는 경우에는 점도가 높은 전극 합제를 사용할 수 있으나, 압력을 인가하는 과정을 포함하지 않는 코팅법을 사용하는 경우에는 낮은 점도의 전극 합제를 사용하는 것이 바람직하다.Specifically, in the case of using a coating method including a method of applying pressure, an electrode mixture having a high viscosity may be used. However, in the case of using a coating method that does not include a process of applying pressure, a low viscosity electrode mixture is used. It is preferable.
한편, 상기 단위 집전체에 전극 합제를 코팅하는 경우, 집전체에 형성된 개방형 기공들에 도입되지 않은 여분의 전극 합제는 단위 집전체의 일면 또는 양면에 도포된 상태로 코팅층을 형성할 수 있다. On the other hand, when the electrode mixture is coated on the unit current collector, the extra electrode mixture not introduced into the open pores formed in the current collector may form a coating layer in a state that is applied to one side or both sides of the unit current collector.
도 4는 도 1의 단위 집전체에 전극 합제가 코팅된 단위 전극의 사시도를 모식적으로 도시하고 있으며, 도 5는 도 4의 A-A' 직선에 따른 수직 절단면을 모식적으로 도시하고 있다.FIG. 4 schematically illustrates a perspective view of a unit electrode coated with an electrode mixture on the unit current collector of FIG. 1, and FIG. 5 schematically illustrates a vertical cut plane along the line AA ′ of FIG. 4.
도 4 및 도 5를 참조하면, 단위 집전체(201)에는 전극 합제(202)가 코팅되어 있는 바, 전극 합제의 점도는 코팅법에 따라 점도 2,000cP 내지 12,000 cP의 범위 내에서 선택될 수 있으며, 적어도 기공들(203)의 일부에는 전극 합제(202)가 도입되어 있다. 또한, 전극 합제의 코팅량이 집전체에 형성된 개방형 기공에 도입될 수 있는 정도 보다 많은 경우에는, 기공에 도입되지 않은 여분의 전극 합제는 집전체의 외표면에 전극 합제층(204)을 형성하게 된다. 이와 같이 단위 집전체의 일측 외면에 코팅되어 있는 전극 합제층이 형성된 단위 전극들을 압연하면 전극 합제층의 두께(d)는 균일하게 형성될 수 있다.4 and 5, the unit current collector 201 is coated with the electrode mixture 202, and the viscosity of the electrode mixture may be selected within the range of viscosity 2,000 cP to 12,000 cP according to the coating method. The electrode mixture 202 is introduced into at least some of the pores 203. In addition, when the coating amount of the electrode mixture is larger than the amount that can be introduced into the open pores formed in the current collector, the extra electrode mixture not introduced into the pores will form the electrode mixture layer 204 on the outer surface of the current collector. . As such, when the unit electrodes having the electrode mixture layer coated on one outer surface of the unit current collector are rolled, the thickness d of the electrode mixture layer may be uniformly formed.
상기 단위 집전체의 일측 외면에 코팅되어 있는 전극 합체층의 두께는 10 ㎛ 내지 100 ㎛일 수 있으며, 더욱 바람직하게는 10 ㎛ 내지 80 ㎛일 수 있다. 상기 단위 집전체의 일측 외면에 코팅되어 있는 전극 합제층의 두께가 10 ㎛ 보다 얇은 경우에는 인접한 단위 전극들 간의 결합력이 약할 수 있으며, 100 ㎛ 보다 두꺼운 경우에는 전해액 함침율이 낮아지는 문제가 발생하거나 리튬 이동의 이동성이 떨어지는 문제가 발생할 수 있으므로 바람직하지 않다.The thickness of the electrode coalescence layer coated on one outer surface of the unit current collector may be 10 μm to 100 μm, and more preferably 10 μm to 80 μm. When the thickness of the electrode mixture layer coated on one outer surface of the unit current collector is thinner than 10 μm, the bonding force between adjacent unit electrodes may be weak, and when the thickness of the electrode mixture layer is thicker than 100 μm, the electrolyte impregnation rate may be low. The problem of inferior mobility of lithium transfer may occur, which is not preferable.
이와 같이, 개방형 기공들이 형성된 전극 집전체에 전극 합제가 코팅되어 형성된 단위 전극들은 복수개가 적층되어 하나의 전극을 구성하는 바, 상기 전극의 두께는 전극 집전체의 두께 내지 집전체의 외면에 코팅되어 있는 전극 합제층의 두께를 고려하여 소망하는 정도의 용량을 갖도록 자유롭게 설정할 수 있는 바, 상기 전극의 두께는 50 ㎛ 내지 500 ㎛일 수 있고, 더욱 바람직하게는 100 ㎛ 내지 500 ㎛일 수 있으며, 가장 바람직하게는 200 ㎛ 내지 450 ㎛ 일 수 있다.As such, a plurality of unit electrodes formed by coating an electrode mixture on an electrode current collector having open pores formed thereon are laminated to form one electrode, and the thickness of the electrode is coated on the outer surface of the current collector to the thickness of the electrode current collector. The thickness of the electrode may be freely set to have a desired capacity in consideration of the thickness of the electrode mixture layer, and the thickness of the electrode may be 50 μm to 500 μm, more preferably 100 μm to 500 μm, and most Preferably from 200 μm to 450 μm.
상기 전극의 두께가 50 ㎛ 보다 작은 경우에는, 고용량의 전지를 제공하기 위한 목적을 달성하기 어렵고, 500 ㎛ 보다 큰 경우에는 적층된 단위 전극들의 개수가 증가함에 따라, 적층 후 압연할 때 또는 이차전지의 사용시에 전극이 한쪽으로 기울어지거나 밀리는 현상이 발생할 수 있으므로 바람직하지 않다.When the thickness of the electrode is smaller than 50 μm, it is difficult to achieve the purpose of providing a high capacity battery, and when the electrode is larger than 500 μm, when the number of stacked unit electrodes increases, when rolling after lamination or secondary battery It is not preferable because the phenomenon that the electrode is inclined or pushed to one side may occur at the time of use.
도 6을 참조하면, 전극(300)은 5개의 단위 전극들(310, 320, 330, 340, 350)이 상호 밀착된 상태로 적층되어 형성되며, 적층된 상태에서 상호 인접한 단위 전극들은 전극 합제를 경유하여 전기적으로 연결되어 있다.Referring to FIG. 6, the electrode 300 is formed by stacking five unit electrodes 310, 320, 330, 340, and 350 in close contact with each other. It is electrically connected via.
한편, 상기 단위 전극들이 적층된 상태에서 서로 밀리는 현상이 발생하는 것을 방지하기 위하여, 상기 단위 전극들은 전극 합제 중의 바인더에 의해 상호 접합되어 있는 구조일 수 있으며, 상기 바인더의 존재로 인하여 전극 합제와 단위 집전체 간의 결합력도 증가시킬 수 있다.Meanwhile, in order to prevent a phenomenon in which the unit electrodes are pushed together in a stacked state, the unit electrodes may have a structure in which the unit electrodes are bonded to each other by a binder in the electrode mixture, and due to the presence of the binder, the electrode mixture and the unit The bonding force between the collectors can also be increased.
또한, 개별적으로 제조된 단위 전극들이 적층된 상태에서 전기전도성이 감소되는 현상을 방지하기 위하여, 적층되는 단위 전극들 사이에 다공성 구조가 없는 일반 집전체가 다양한 모양으로 개재될 수 있는 바, 상기 일반 집전체는 하나의 전극에 적어도 1개 이상 개재될 수 있으며, 예를 들어, 상기 일반 집전체로서 양극은 알루미늄 집전체가 사용되고, 음극은 구리 호일 집전체가 사용될 수 있다.In addition, in order to prevent a phenomenon in which electrical conductivity is reduced in a state in which unit electrodes are manufactured separately, a general current collector having no porous structure may be interposed in various shapes between the unit electrodes to be stacked. At least one current collector may be interposed in one electrode. For example, as the general current collector, an anode may be an aluminum current collector, and a cathode may be a copper foil current collector.
본 발명에 있어, 상기 전극(300)은 집전체 내부의 기공들 내부로 전극 합제를 도입하여 단위 전극의 두께를 줄이기 위하여 단위 전극을 압연할 수 있는 바, 개별 단위 전극들을 압연한 후 적층하는 방법을 사용할 수 있으며, 단위 전극들을 개별적으로 압연하지 않고 단위 전극들을 적층한 상태에서 압연할 수도 있다.In the present invention, the electrode 300 can roll the unit electrode in order to reduce the thickness of the unit electrode by introducing the electrode mixture into the pores inside the current collector, the method of stacking the individual unit electrodes after rolling May be used, and the unit electrodes may be rolled in a state of stacking the unit electrodes without individually rolling the unit electrodes.
본 발명은 상기의 이차전지용 전극으로 이루어진 양극 또는 음극 중의 적어도 어느 하나와 전해액이 셀 케이스에 내장되어 형성된 구조의 전지셀을 제공하며, 상기 전해액은 이차전지용 전극에서 단위 집전체의 개방형 기공 내로 유입될 수 있는 바, 단위 집전체의 개방형 기공 내로 유입된 전극 합제가 전해액에 함침될 수 있으므로 용량이 감소되는 것을 방지할 수 있다.The present invention provides a battery cell having a structure in which at least one of the positive electrode or the negative electrode including the secondary battery electrode and the electrolyte is formed in the cell case, and the electrolyte flows into the open pores of the unit current collector from the secondary battery electrode. Since the electrode mixture introduced into the open pores of the unit current collector may be impregnated in the electrolyte, the capacity may be prevented from being reduced.
본 발명은 또한, 상기의 이차전지용 전극의 제조방법으로서, The present invention also provides a method for manufacturing the above secondary battery electrode,
(a) 3차원 망상형 구조의 단위 집전체 및 전극 슬러리를 준비하는 과정;(a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure;
(b) 전극 슬러리를 단위 집전체에 코팅하는 과정;(b) coating the electrode slurry on a unit current collector;
(c) 전극 슬러리를 건조하여 전극 합제층을 형성하는 과정;(c) drying the electrode slurry to form an electrode mixture layer;
(d) 단위 전극들을 압연하는 과정; 및(d) rolling unit electrodes; And
(e) 단위 전극들을 적층하는 과정;(e) stacking unit electrodes;
을 포함하는 이차전지용 전극의 제조방법을 제공한다.It provides a method of manufacturing a secondary battery electrode comprising a.
이와 같이, 상기 이차전지용 전극은 전극 슬러리를 다공성 구조의 단위 집전체에 코팅하기 때문에, 전극 슬러리가 단위 집전체 내부의 기공으로 이동하여 단위 집전체 내부에 전극 슬러리가 채워질 수 있다. 이와 같이 집전체 내부에 전극 슬러리가 채워진 상태에서 전극 슬러리를 건조하고 단위 전극들을 압연하기 때문에, 단위 전극들의 두께가 균일하게 형성될 수 있는 장점이 있다. As described above, since the electrode for secondary batteries coats the electrode slurry on the unit current collector having a porous structure, the electrode slurry may move to pores inside the unit current collector to fill the electrode slurry inside the unit current collector. As such, since the electrode slurry is dried and the unit electrodes are rolled in the state in which the electrode slurry is filled in the current collector, the thickness of the unit electrodes may be uniformly formed.
또한, 본 발명은 상기 이차전지용 전극의 제조방법으로서,In addition, the present invention is a manufacturing method of the electrode for secondary batteries,
(a) 3차원 망상형 구조의 단위 집전체 및 전극 슬러리를 준비하는 과정;(a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure;
(b) 전극 슬러리를 단위 집전체에 코팅하는 과정;(b) coating the electrode slurry on a unit current collector;
(c) 전극 슬러리를 건조하여 전극 합제층을 형성하는 과정;(c) drying the electrode slurry to form an electrode mixture layer;
(d) 단위 전극들을 적층하는 과정; 및(d) stacking unit electrodes; And
(e) 적층된 단위 전극들을 압연하는 과정 (e) rolling the stacked unit electrodes
을 포함하는 이차전지용 전극의 제조방법을 제공한다.It provides a method of manufacturing a secondary battery electrode comprising a.
이와 같이, 상기 이차전지용 전극은 전극 슬러리를 다공성 구조의 단위 집전체에 코팅하기 때문에, 전극 슬러리가 단위 집전체의 기공으로 이동하여 단위 집전체 내부에 전극 슬러리가 채워질 수 있다. 이와 같이 전극 슬러리가 단위 집전체 내부에 채워진 상태에서 전극 슬러리를 건조하고, 전극 합제층이 형성된 상기 단위 전극들을 적층한 후 상기 적층된 단위 전극들을 압연한다.As described above, since the electrode for secondary batteries coats the electrode slurry on the unit current collector having a porous structure, the electrode slurry may move to the pores of the unit current collector to fill the electrode slurry inside the unit current collector. As such, the electrode slurry is dried while the electrode slurry is filled in the unit current collector, the unit electrodes on which the electrode mixture layer is formed are stacked, and the stacked unit electrodes are rolled.
이와 같이, 개별 단위 전극들을 압연하는 과정이 생략하고, 적층된 단위 전극들에 대한 압연을 실시하기 때문에 제조 과정의 효율성이 향상될 수 있다.As such, since the process of rolling the individual unit electrodes is omitted and the rolling of the stacked unit electrodes is performed, the efficiency of the manufacturing process can be improved.
본 발명은 또한, 상기 전극을 포함하는 리튬 이차전지를 제공한다.The present invention also provides a lithium secondary battery comprising the electrode.
상기 리튬 이차전지는 상기 양극, 음극, 분리막 및 리튬염 함유 비수 전해질로 구성될 수 있고, 당 기술 분야에 알려져 있는 통상적인 방법으로 양극과 음극 사이에 다공성의 분리막을 넣고 상기 전해질을 투입하여 제조될 수 있다.The lithium secondary battery may be composed of the positive electrode, the negative electrode, the separator and the lithium salt-containing non-aqueous electrolyte, and is prepared by putting the electrolyte into a porous separator between the positive electrode and the negative electrode in a conventional manner known in the art. Can be.
본 발명에 따른 상기 전극은 양극 또는 음극 중에서 선택되는 하나 이상일 수 있다. 즉, 양극 및/또는 음극 모두가 본 발명에 따른 전극 구조를 가질 수 있고, 양극 및 음극 중 어느 하나의 전극만이 본 발명에 따른 전극 구조를 가질 수도 있으며 특별히 한정되지 아니하고 필요에 따라 적절하게 선택할 수 있다. The electrode according to the present invention may be one or more selected from the positive electrode or the negative electrode. That is, both the positive electrode and / or the negative electrode may have an electrode structure according to the present invention, and only one electrode of the positive electrode and the negative electrode may have the electrode structure according to the present invention and is not particularly limited and may be appropriately selected as necessary. Can be.
구체적으로 양극은 예를들어, 본 발명의 3차원 망상 구조의 단위 집전체 상에 양극 활물질, 도전재 및 바인더의 혼합물 슬러리를 도포한 후 건조하여 제조될 수 있으며, 필요에 따라서는 상기 혼합물에 충진제를 더 첨가할 수 있다.Specifically, the positive electrode may be prepared by, for example, applying a slurry of a mixture of a positive electrode active material, a conductive material, and a binder onto a unit current collector having a three-dimensional network structure according to the present invention, followed by drying. More may be added.
상기 양극 활물질은 리튬 코발트 산화물(LiCoO2), 리튬 니켈 산화물(LiNiO2) 등의 층상 화합물이나 1 또는 그 이상의 전이금속으로 치환된 화합물; 화학식 Li1+xMn2-xO4 (여기서, x 는 0 ~ 0.33 임), LiMnO3, LiMn2O3, LiMnO2 등의 리튬 망간 산화물; 리튬 동 산화물(Li2CuO2); LiV3O8, LiFe3O4, V2O5, Cu2V2O7 등의 바나듐 산화물; 화학식 LiNi1 - xMxO2 (여기서, M = Co, Mn, Al, Cu, Fe, Mg, B 또는 Ga 이고, x = 0.01 ~ 0.3 임)으로 표현되는 Ni 사이트형 리튬 니켈 산화물; 화학식 LiMn2 - xMxO2 (여기서, M = Co, Ni, Fe, Cr, Zn 또는 Ta 이고, x = 0.01 ~ 0.1 임) 또는 Li2Mn3MO8 (여기서, M = Fe, Co, Ni, Cu 또는 Zn 임)으로 표현되는 리튬 망간 복합 산화물; LiNixMn2 - xO4로 표현되는 스피넬 구조의 리튬 망간 복합 산화물; 화학식의 Li 일부가 알칼리토금속 이온으로 치환된 LiMn2O4; 디설파이드 화합물; Fe2(MoO4)3 등을 들 수 있지만, 이들만으로 한정되는 것은 아니다.The positive electrode active material may be a layered compound such as lithium cobalt oxide (LiCoO 2 ), lithium nickel oxide (LiNiO 2 ), or a compound substituted with one or more transition metals; Lithium manganese oxides such as Li 1 + x Mn 2-x O 4 (where x is 0 to 0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2, and the like; Lithium copper oxide (Li 2 CuO 2 ); Vanadium oxides such as LiV 3 O 8 , LiFe 3 O 4 , V 2 O 5 , Cu 2 V 2 O 7 and the like; Ni-site type lithium nickel oxide represented by the formula LiNi 1 - x M x O 2 , wherein M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and x = 0.01 to 0.3; Formula LiMn 2 - x M x O 2 (wherein M = Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li 2 Mn 3 MO 8 (wherein M = Fe, Co, Lithium manganese composite oxide represented by Ni, Cu or Zn); Spinel-structure lithium manganese composite oxides represented by LiNi x Mn 2 - x O 4 ; LiMn 2 O 4 in which a part of Li in the formula is substituted with alkaline earth metal ions; Disulfide compounds; Fe 2 (MoO 4 ) 3 and the like, but are not limited to these.
상기 도전재는 통상적으로 양극 활물질을 포함한 혼합물 전체 중량을 기준으로 1 내지 30 중량%로 첨가된다. 이러한 도전재는 당해 전지에 화학적 변화를 유발하지 않으면서 도전성을 가진 것이라면 특별히 제한되는 것은 아니며, 예를 들어, 천연 흑연이나 인조 흑연 등의 흑연; 카본블랙, 아세틸렌 블랙, 케첸 블랙, 채널 블랙, 퍼네이스 블랙, 램프 블랙, 서머 블랙 등의 카본블랙; 탄소 섬유나 금속 섬유 등의 도전성 섬유; 불화 카본, 알루미늄, 니켈 분말 등의 금속 분말; 산화아연, 티탄산 칼륨 등의 도전성 위스키; 산화 티탄 등의 도전성 금속 산화물; 폴리페닐렌 유도체 등의 도전성 소재 등이 사용될 수 있다.The conductive material is typically added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Such a conductive material is not particularly limited as long as it has conductivity without causing chemical change in the battery, and examples thereof include graphite such as natural graphite and artificial graphite; Carbon blacks such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fibers and metal fibers; Metal powders such as carbon fluoride powder, aluminum powder and nickel powder; Conductive whiskeys such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.
상기 바인더는 활물질과 도전재 등의 결합과 집전체에 대한 결합에 조력하는 성분으로서, 통상적으로 양극 활물질을 포함하는 혼합물 전체 중량을 기준으로 1 내지 30 중량%로 첨가된다. 이러한 바인더의 예로는, 폴리불화비닐리덴, 폴리비닐알코올, 카르복시메틸셀룰로우즈(CMC), 전분, 히드록시프로필셀룰로우즈, 재생 셀룰로우즈, 폴리비닐피롤리돈, 테트라플루오로에틸렌, 폴리에틸렌, 폴리프로필렌, 에틸렌-프로필렌-디엔 테르 폴리머(EPDM), 술폰화 EPDM, 스티렌 브티렌 고무, 불소 고무, 다양한 공중합체 등을 들 수 있다.The binder is a component that assists the bonding of the active material and the conductive material to the current collector, and is generally added in an amount of 1 to 30 wt% based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, various copolymers and the like.
상기 충진제는 양극의 팽창을 억제하는 성분으로서 선택적으로 사용되며, 당해 전지에 화학적 변화를 유발하지 않으면서 섬유상 재료라면 특별히 제한되는 것은 아니며, 예를 들어, 폴리에틸렌, 폴리프로필렌 등의 올리핀계 중합체; 유리섬유, 탄소섬유 등의 섬유상 물질이 사용된다.The filler is optionally used as a component for inhibiting expansion of the positive electrode, and is not particularly limited as long as it is a fibrous material without causing chemical change in the battery. Examples of the filler include olefinic polymers such as polyethylene and polypropylene; Fibrous materials, such as glass fiber and carbon fiber, are used.
구체적으로 음극은 예를들어, 본 발명의 3차원 망상 구조의 단위 집전체 상에 음극 활물질, 도전재 및 바인더의 혼합물 슬러리를 도포한 후 건조하여 제조될 수 있으며, 필요에 따라서는 상기 혼합물에 충진제를 더 첨가할 수 있다.Specifically, the negative electrode may be prepared by, for example, applying a slurry of a mixture of a negative electrode active material, a conductive material, and a binder onto a unit current collector having a three-dimensional network structure according to the present invention, followed by drying. More may be added.
상기 음극 활물질은, 예를 들어, 난흑연화 탄소, 흑연계 탄소 등의 탄소; LixFe2O3(0≤x≤1), LixWO2(0≤x≤1), SnxMe1 - xMe'yOz (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, 주기율표의 1족, 2족, 3족 원소, 할로겐; 0<x≤1; 1≤y≤3; 1≤z≤8) 등의 금속 복합 산화물; 리튬 금속; 리튬 합금; 규소계 합금; 주석계 합금; SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, and Bi2O5 등의 금속 산화물; 폴리아세틸렌 등의 도전성 고분자; Li-Co-Ni 계 재료; 티타늄 산화물; 리튬 티타늄 산화물 등을 들 수 있다.The negative electrode active material may be, for example, carbon such as hardly graphitized carbon or graphite carbon; Li x Fe 2 O 3 (0 ≦ x ≦ 1), Li x WO 2 (0 ≦ x ≦ 1), Sn x Me 1 - x Me ' y O z (Me: Mn, Fe, Pb, Ge; Me' Metal complex oxides such as Al, B, P, Si, Group 1, Group 2, Group 3 elements of the periodic table, halogen, 0 <x ≦ 1; 1 ≦ y ≦ 3; 1 ≦ z ≦ 8); Lithium metal; Lithium alloys; Silicon-based alloys; Tin-based alloys; SnO, SnO 2 , PbO, PbO 2 , Pb 2 O 3 , Pb 3 O 4 , Sb 2 O 3 , Sb 2 O 4 , Sb 2 O 5 , GeO, GeO 2 , Bi 2 O 3 , Bi 2 O 4 , and metal oxides such as Bi 2 O 5 ; Conductive polymers such as polyacetylene; Li-Co-Ni-based materials; Titanium oxide; Lithium titanium oxide, and the like.
한편, 본 발명에 따른 상기 전극이 양극이고, 양극 활물질로 일반적으로 사용되는 리튬 전이금속 산화물을 포함하는 경우, 상기 양극은 로딩량이 700mg/25 cm2 이상까지 가능하고, 상기 전극이 음극이고, 음극 활물질로 일반적으로 사용되는 탄소재를 포함하는 경우, 상기 음극의 로딩량은 300mg/25 cm2이상까지 가능하다.On the other hand, when the electrode according to the present invention is a positive electrode, and contains a lithium transition metal oxide generally used as a positive electrode active material, the positive electrode has a loading amount of 700 mg / 25 cm 2 When the above is possible, and the electrode is a negative electrode and includes a carbon material generally used as a negative electrode active material, the loading amount of the negative electrode may be up to 300 mg / 25 cm 2 or more.
본 발명에 따른 이차전지의 기타 성분들에 대해서는 이하에서 설명하다.Other components of the secondary battery according to the present invention will be described below.
상기 분리막은 양극과 음극 사이에 개재되며, 높은 이온 투과도와 기계적 강도를 가지는 절연성의 얇은 박막이 사용된다. 분리막의 기공 직경은 일반적으로 0.01 ~ 10 ㎛이고, 두께는 일반적으로 5 ~ 300 ㎛이다. 이러한 분리막으로는, 예를 들어, 내화학성 및 소수성의 폴리프로필렌 등의 올레핀계 폴리머; 유리섬유 또는 폴리에틸렌 등으로 만들어진 시트나 부직포 등이 사용된다. 전해질로서 폴리머 등의 고체 전해질이 사용되는 경우에는 고체 전해질이 분리막을 겸할 수도 있다.The separator is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally from 0.01 to 10 ㎛ ㎛, thickness is generally 5 ~ 300 ㎛. As such a separator, for example, olefin polymers such as chemical resistance and hydrophobic polypropylene; Sheets or non-woven fabrics made of glass fibers or polyethylene are used. When a solid electrolyte such as a polymer is used as the electrolyte, the solid electrolyte may also serve as a separator.
상기 리튬염 함유 비수 전해질은, 비수 전해질과 리튬으로 이루어져 있고, 비수 전해질로는 비수계 유기용매, 유기 고체 전해질, 무기 고체 전해질 등이 사용되지만 이들만으로 한정되는 것은 아니다.The lithium salt-containing nonaqueous electrolyte is composed of a nonaqueous electrolyte and lithium. A nonaqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte and the like are used as the nonaqueous electrolyte, but are not limited thereto.
상기 비수계 유기용매로는, 예를 들어, N-메틸-2-피롤리디논, 프로필렌 카르보네이트, 에틸렌 카르보네이트, 부틸렌 카르보네이트, 디메틸 카르보네이트, 디에틸 카르보네이트, 감마-부틸로 락톤, 1,2-디메톡시 에탄, 테트라히드록시 프랑(franc), 2-메틸 테트라하이드로푸란, 디메틸술폭시드, 1,3-디옥소런, 포름아미드, 디메틸포름아미드, 디옥소런, 아세토니트릴, 니트로메탄, 포름산 메틸, 초산메틸, 인산 트리에스테르, 트리메톡시 메탄, 디옥소런 유도체, 설포란, 메틸 설포란, 1,3-디메틸-2-이미다졸리디논, 프로필렌 카르보네이트 유도체, 테트라하이드로푸란 유도체, 에테르, 피로피온산 메틸, 프로피온산 에틸 등의 비양자성 유기용매가 사용될 수 있다.Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and gamma Butyl lactone, 1,2-dimethoxy ethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxorone, formamide, dimethylformamide, dioxolon , Acetonitrile, nitromethane, methyl formate, methyl acetate, phosphate triester, trimethoxy methane, dioxorone derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbo Aprotic organic solvents such as nate derivatives, tetrahydrofuran derivatives, ethers, methyl pyroionate and ethyl propionate can be used.
상기 유기 고체 전해질로는, 예를 들어, 폴리에틸렌 유도체, 폴리에틸렌 옥사이드 유도체, 폴리프로필렌 옥사이드 유도체, 인산 에스테르 폴리머, 폴리 에지테이션 리신(agitation lysine), 폴리에스테르 술파이드, 폴리비닐 알코올, 폴리 불화 비닐리덴, 이온성 해리기를 포함하는 중합제 등이 사용될 수 있다.Examples of the organic solid electrolyte include polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyedgetion lysine, polyester sulfides, polyvinyl alcohols, polyvinylidene fluorides, Polymerizers containing ionic dissociating groups and the like can be used.
상기 무기 고체 전해질로는, 예를 들어, Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, Li3PO4-Li2S-SiS2 등의 Li의 질화물, 할로겐화물, 황산염 등이 사용될 수 있다.Examples of the inorganic solid electrolyte include Li 3 N, LiI, Li 5 NI 2 , Li 3 N-LiI-LiOH, LiSiO 4 , LiSiO 4 -LiI-LiOH, Li 2 SiS 3 , Li 4 SiO 4 , Nitrides, halides, sulfates and the like of Li, such as Li 4 SiO 4 -LiI-LiOH, Li 3 PO 4 -Li 2 S-SiS 2 , and the like, may be used.
상기 리튬염은 상기 비수계 전해질에 용해되기 좋은 물질로서, 예를 들어, LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, (CF3SO2)2NLi, 클로로 보란 리튬, 저급 지방족 카르본산 리튬, 4 페닐 붕산 리튬, 이미드 등이 사용될 수 있다.The lithium salt is a good material to be dissolved in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6, LiSbF 6, LiAlCl 4, CH 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide.
또한, 전해액에는 충방전 특성, 난연성 등의 개선을 목적으로, 예를 들어, 피리딘, 트리에틸포스파이트, 트리에탄올아민, 환상 에테르, 에틸렌 디아민, n-글라임(glyme), 헥사 인산 트리 아미드, 니트로벤젠 유도체, 유황, 퀴논 이민 염료, N-치환 옥사졸리디논, N,N-치환 이미다졸리딘, 에틸렌 글리콜 디알킬 에테르, 암모늄염, 피롤, 2-메톡시 에탄올, 삼염화 알루미늄 등이 첨가될 수도 있다. 경우에 따라서는, 불연성을 부여하기 위하여, 사염화탄소, 삼불화에틸렌 등의 할로겐 함유 용매를 더 포함시킬 수도 있고, 고온 보존 특성을 향상시키기 위하여 이산화탄산 가스를 더 포함시킬 수도 있으며, FEC(Fluoro-Ethylene Carbonate), PRS(Propene sultone) 등을 더 포함시킬 수 있다.In addition, in the electrolyte solution, for the purpose of improving the charge and discharge characteristics, flame retardancy, etc., for example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, hexaphosphate triamide, nitro Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrroles, 2-methoxy ethanol, aluminum trichloride and the like may be added. . In some cases, in order to impart nonflammability, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride may be further included, and carbon dioxide gas may be further included to improve high temperature storage characteristics, and FEC (Fluoro-Ethylene) may be further included. Carbonate), PRS (Propene sultone) may be further included.
하나의 구체적인 예에서, LiPF6, LiClO4, LiBF4, LiN(SO2CF3)2 등의 리튬염을, 고유전성 용매인 EC 또는 PC의 환형 카보네이트와 저점도 용매인 DEC, DMC 또는 EMC의 선형 카보네이트의 혼합 용매에 첨가하여 리튬염 함유 비수계 전해질을 제조할 수 있다.In one specific example, lithium salts such as LiPF 6 , LiClO 4 , LiBF 4 , LiN (SO 2 CF 3 ) 2, and the like, may be prepared by cyclic carbonate of EC or PC, which is a highly dielectric solvent, and DEC, DMC, or EMC, which are low viscosity solvents. Lithium salt-containing non-aqueous electrolytes can be prepared by adding them to a mixed solvent of linear carbonates.
본 발명은 또한, 상기 이차전지용 전극으로 구성된 전극조립체가 전해액과 함께 전지케이스의 내부에 밀봉되어 있는 이차전지를 제공하는 바, 상기 이차전지는 소형 디바이스의 전원으로 사용되는 전지셀에 사용될 수 있을 뿐만 아니라, 고온 안정성 및 긴 사이클 특성과 높은 레이트 특성 등이 요구되는 중대형 디바이스의 전원으로 사용되는 다수의 전지셀들을 포함하는 전지팩 및 상기 전지팩을 전원으로서 포함하는 디바이스에 단위전지로도 바람직하게 사용될 수 있다.The present invention also provides a secondary battery in which an electrode assembly composed of the electrode for secondary batteries is sealed inside the battery case together with an electrolyte, and the secondary battery may be used in a battery cell used as a power source for a small device. In addition, a battery pack including a plurality of battery cells used as a power source for medium and large devices requiring high temperature stability, long cycle characteristics, high rate characteristics, and the like, may be preferably used as a unit battery in a device including the battery pack as a power source. Can be.
상기 디바이스는 구체적으로 모바일 전자기기, 전지 기반 모터에 의해 동력을 받아 움직이는 파워 툴(power tool); 전기자동차(Electric Vehicle, EV), 하이브리드 전기자동차(Hybrid Electric Vehicle, HEV), 플러그-인 하이브리드 전기자동차(Plug-in Hybrid Electric Vehicle, PHEV) 등을 포함하는 전기차; 전기 자전거(E-bike), 전기 스쿠터(E-scooter)를 포함하는 전기 이륜차; 전기 골프 카트(electric golf cart); 전력저장용 시스템에서 선택되는 어느 하나일 수 있으나, 이에 한정되는 것은 아니다.The device specifically includes a power tool that is powered by a mobile electronic device, a battery-based motor; Electric vehicles including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and the like; Electric motorcycles including electric bicycles (E-bikes) and electric scooters (E-scooters); Electric golf carts; It may be any one selected from the system for power storage, but is not limited thereto.
상기와 같은 디바이스 내지 장치들은 당업계에 공지되어 있으므로, 본 명세서에서는 그에 대한 구체적인 설명을 생략한다.Since such devices or apparatuses are known in the art, detailed description thereof will be omitted herein.
이하 본 발명의 실시예를 참조하여 설명하지만, 하기 실시예는 본 발명을 예시하기 위한 것이며, 본 발명의 범주가 이들만으로 한정되는 것은 아니다. Hereinafter, the present invention will be described with reference to Examples, but the following Examples are provided to illustrate the present invention, and the scope of the present invention is not limited thereto.
<실시예 1><Example 1>
양극의 제조Manufacture of anode
양극 활물질 LiNi0 . 55Mn0 . 30Co0 . 15O2 , 도전재인 Denka black 및 바인더인 폴리비닐리덴 플루오라이드(polyvinylidene fluoride)를 중량비 96:2:2으로 혼합한 후, NMP(N-methyl pyrrolidone)를 첨가하여 슬러리를 제조하였다. Cathode active material LiNi 0 . 55 Mn 0 . 30 Co 0 . 15 O 2 , Denka black as a conductive material , and polyvinylidene fluoride (polyvinylidene fluoride) as a binder were mixed in a weight ratio of 96: 2: 2, and NMP (N-methyl pyrrolidone) was added to prepare a slurry.
기공의 평균직경이 20㎛이고, 종횡비(aspect ratio)가 100이며, 두께가 40㎛인 알루미늄 펠트에 상기 슬러리를 코팅해 단위 양극을 얻었다. 상기 단위 양극을 120℃의 진공오븐에서 건조한 후, 건조된 단위 양극 2개를 적층하고, 압연하여 양극을 제조하였다. 이때 집전체 포함 전극의 두께는 75㎛였다. The slurry was coated on aluminum felt having an average diameter of pores of 20 μm, an aspect ratio of 100, and a thickness of 40 μm to obtain a unit anode. After drying the unit positive electrode in a vacuum oven at 120 ℃, laminated two dried unit positive electrode and rolled to prepare a positive electrode. At this time, the thickness of the electrode including the current collector was 75 μm.
리튬 이차전지의 제조Fabrication of Lithium Secondary Battery
상대(counter) 전극으로 구리(Cu) 호일에 리튬 메탈(40㎛)을 붙여 사용하였고, 상기 양극과 상기 상대 전극 사이에 폴리올레핀 세퍼레이터를 개재시킨 후, 에틸렌 카보네이트(EC), 에틸메틸 카보네이트(DEC)를 50:50의 부피비로 혼합한 용매에 1M 육불화인산리튬(LiPF6)이 용해된 전해액을 주입하여 파우치형 반쪽전지를 제조하였다.Lithium metal (40 μm) was attached to copper (Cu) foil as a counter electrode, and a polyolefin separator was interposed between the positive electrode and the counter electrode, followed by ethylene carbonate (EC) and ethyl methyl carbonate (DEC). P-type half cell was prepared by injecting an electrolyte solution in which 1 M lithium hexafluorophosphate (LiPF 6 ) was dissolved in a solvent mixed at a volume ratio of 50:50.
<실시예 2 내지 4><Examples 2 to 4>
집전체 기공의 평균직경을 표 1과 같이 변경한 것을 제외하고는 실시예 1과 동일한 방법으로 리튬 이차전지를 제조하였다. A lithium secondary battery was manufactured in the same manner as in Example 1, except that the average diameter of the current collector pores was changed as shown in Table 1.
<실시예 5>Example 5
알루미늄 펠트의 두께를 55㎛로 변경한 점, 집전체 포함 전극의 두께를 102㎛로 조절한 점을 제외하고는, 실시예 1과 동일한 방법으로 리튬 이차전지를 제조하였다. A lithium secondary battery was manufactured in the same manner as in Example 1, except that the thickness of the aluminum felt was changed to 55 μm and the thickness of the electrode including the current collector was adjusted to 102 μm.
<실시예 6 내지 8><Examples 6 to 8>
집전체 기공의 평균직경을 표 1과 같이 변경한 것을 제외하고는 실시예 5와 동일한 방법으로 리튬 이차전지를 제조하였다.A lithium secondary battery was manufactured in the same manner as in Example 5, except that the average diameter of the current collector pores was changed as shown in Table 1.
<비교예 1>Comparative Example 1
양극의 제조Manufacture of anode
양극 활물질 LiNi0 . 55Mn0 . 30Co0 . 15O2 , 도전재인 Denka black 및 바인더인 폴리비닐리덴 플루오라이드(polyvinylidene fluoride)를 중량비 96:2:2으로 혼합한 후, NMP(N-methyl pyrrolidone)를 첨가하여 슬러리를 제조하였다. 이러한 양극 슬러리를 2개의 알루미늄의 사이 및 외면에 3층으로 도포한 후 120℃의 진공오븐에서 건조하여 양극을 제조하였다. 이 때, 전극의 두께는 집전체의 두께를 포함하여 75㎛가 되도록 하였으며, 집전체의 두께는 12마이크로미터이다.Cathode active material LiNi 0 . 55 Mn 0 . 30 Co 0 . 15 O 2 , Denka black as a conductive material , and polyvinylidene fluoride (polyvinylidene fluoride) as a binder were mixed in a weight ratio of 96: 2: 2, and NMP (N-methyl pyrrolidone) was added to prepare a slurry. The positive electrode slurry was applied in three layers between the two aluminum and the outer surface, and dried in a vacuum oven at 120 ° C. to prepare a positive electrode. At this time, the thickness of the electrode was 75㎛ including the thickness of the current collector, the thickness of the current collector is 12 micrometers.
리튬 이차전지의 제조Fabrication of Lithium Secondary Battery
상대(counter) 전극으로 구리(Cu) 호일에 리튬 메탈(40㎛)을 붙여 사용하였고, 상기 양극과 상기 상대 전극 사이에 폴리올레핀 세퍼레이터를 개재시킨 후, 에틸렌 카보네이트(EC), 에틸메틸 카보네이트(DEC)를 50:50의 부피비로 혼합한 용매에 1M 육불화인산리튬(LiPF6)이 용해된 전해액을 주입하여 파우치형 반쪽전지를 제조하였다.Lithium metal (40 μm) was attached to copper (Cu) foil as a counter electrode, and a polyolefin separator was interposed between the positive electrode and the counter electrode, followed by ethylene carbonate (EC) and ethyl methyl carbonate (DEC). P-type half cell was prepared by injecting an electrolyte solution in which 1 M lithium hexafluorophosphate (LiPF 6 ) was dissolved in a solvent mixed at a volume ratio of 50:50.
<비교예 2>Comparative Example 2
집전체를 포함하는 전극의 두께를 표 1과 같이 변경한 것을 제외하고는 비교예 1과 동일한 방법으로 리튬 이차전지를 제조하였다.A lithium secondary battery was manufactured in the same manner as in Comparative Example 1, except that the thickness of the electrode including the current collector was changed as in Table 1.
<실험예 > 수명특성 평가 Experimental Example
본 발명에 따른 전극의 수명특성을 평가하기 위하여 하기와 같은 실험을 실시하였다. In order to evaluate the life characteristics of the electrode according to the present invention was carried out the following experiment.
실시예 및 비교예에서 제조된 전지들에 대하여, 4.2V 내지 2.5V 사이에서 1/3C ↔ 1/3C (1회 충방전)의 조건으로 실시하였다. 수명특성은 방전용량 유지율로부터 평가하였으며, 상기 방전용량유지율은 충방전을 200회 반복 실시한 후의 용량을 초기용량에 대한 %비율로 나타내었다. 그 결과를 표 1에 나타내었다.The batteries prepared in Examples and Comparative Examples were carried out under conditions of 1 / 3C to 1 / 3C (one time charge and discharge) between 4.2V and 2.5V. The lifetime characteristics were evaluated from the discharge capacity retention rate, and the discharge capacity retention rate was expressed as a percentage of the initial capacity after the charge and discharge was repeated 200 times. The results are shown in Table 1.
집전체 기공의 평균 직경(㎛)Average diameter of current collector pores (㎛) 집전체 포함 전극의 두께(㎛)Thickness of Electrode with Current Collector (μm) 수명특성Life characteristic
초기 방전 용량(mAh/㎠)Initial discharge capacity (mAh / ㎠) 200회 사이클 후 용량(mAh/㎠)Capacity after 200 cycles (mAh / ㎠) 200회 용량 유지율(%)200 capacity retention rate (%)
실시예 1Example 1 2020 7575 3.4313.431 3.1633.163 92.292.2
실시예 2Example 2 3030 7575 3.8643.864 3.5783.578 92.692.6
실시예 3Example 3 5050 7575 3.7153.715 3.4443.444 92.792.7
실시예 4Example 4 8080 7575 3.4493.449 3.1973.197 92.792.7
실시예 5Example 5 2020 102102 3.3133.313 2.9322.932 88.588.5
실시예 6Example 6 3030 102102 3.7533.753 3.3183.318 88.488.4
실시예 7Example 7 5050 102102 3.6233.623 3.2243.224 89.089.0
실시예 8Example 8 8080 102102 3.3303.330 2.9572.957 88.888.8
비교예 1Comparative Example 1 -- 7575 3.6433.643 3.3563.356 92.192.1
비교예 2Comparative Example 2 -- 102102 3.4463.446 2.9392.939 85.385.3
상기 표 1을 참조하면, 실시예 1 내자 4와 비교예 1은 전극의 두께가 동일함에도 실시예 1 내지 4의 전지가 비교예 1의 전지 대비 수명 특성이 유사 수준이거나, 더 우수함을 확인할 수 있다. Referring to Table 1, Examples 1 to 4 and Comparative Example 1, even though the thickness of the electrode is the same as the electrode of the battery of Examples 1 to 4 compared to the battery of Comparative Example 1 or even better, it can be seen that better. .
그리고 이와 같은 현상은 고로딩에서 더욱 분명한 차이가 나타난다. 실시예 5 내지 8과 비교예 2는 전극 두께가 동일한 고로딩 전극인데, 비교예 2는 수명특성이 많이 저하되는 반면, 실시예 5 내지 8은 비교예 2에 비해 우수한 수명 특성을 유지하는 것이 확인된다. And this phenomenon is more obvious in loading. Examples 5 to 8 and Comparative Example 2 is a high-loading electrode having the same electrode thickness, Comparative Example 2 has a much lower life characteristics, while Examples 5 to 8 is confirmed to maintain excellent life characteristics compared to Comparative Example 2 do.
이는 본 발명의 전극이 비교예의 전극에 비해 전극 집전체와 활물질 간의 물리적인 거리 감소에 따른 반응 거리를 단축해 전극 내 저항이 감소하였을 뿐만 아니라, 3차원 망상 구조가 활물질 층을 지지하는 지지체의 역할을 함으로써 전극 내 활물질 층과 집전체의 탈리 가능성을 감소시켰기 때문인 것으로 판단된다. This is because the electrode of the present invention shortens the reaction distance due to the decrease in the physical distance between the electrode current collector and the active material compared to the electrode of the comparative example, thereby reducing the resistance in the electrode, and the role of the support that the three-dimensional network structure supports the active material layer. It is believed that this is because the possibility of detachment of the active material layer and the current collector in the electrode is reduced.
본 발명이 속한 분야에서 통상의 지식을 가진 자라면 상기 내용을 바탕으로 본 발명의 범주 내에서 다양한 응용 및 변형을 수행하는 것이 가능할 것이다.Those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

Claims (14)

  1. 이차전지용 전극으로서,As an electrode for secondary batteries,
    둘 이상의 단위 전극들이 상호 밀착된 상태로 적층되어 있고,Two or more unit electrodes are stacked in close contact with each other,
    상호 인접한 단위 전극들은 전극 합제를 경유하여 전기적으로 연결되어 있으며,Adjacent unit electrodes are electrically connected via an electrode mixture,
    각각의 단위 전극은, 3차원 망상형 구조를 가지는 단위 집전체의 기공에 전극 활물질을 포함하는 전극 합제가 도입되어 있는 것을 특징으로 하는 이차전지용 전극.Each unit electrode is a secondary battery electrode, characterized in that the electrode mixture containing the electrode active material is introduced into the pores of the unit current collector having a three-dimensional network structure.
  2. 제 1 항에 있어서, 상기 전극은 2개 내지 10개의 단위 전극들이 적층된 구조로 이루어진 것을 특징으로 하는 이차전지용 전극.The electrode of claim 1, wherein the electrode has a structure in which two to ten unit electrodes are stacked.
  3. 제 1 항에 있어서, 상기 3차원 망상형 구조를 가지는 단위 집전체는 도전성 금속 펠트인 것을 특징으로 하는 이차전지용 전극.The electrode for secondary batteries according to claim 1, wherein the unit current collector having the three-dimensional network structure is a conductive metal felt.
  4. 제 1 항에 있어서, 상기 3차원 망상형 구조를 가지는 단위 집전체의 평균 두께는 30 ㎛ 내지 400 ㎛인 것을 특징으로 하는 이차전지용 전극.The secondary battery electrode of claim 1, wherein an average thickness of the unit current collector having the three-dimensional network structure is 30 μm to 400 μm.
  5. 제 1 항에 있어서, 상기 3차원 망상형 구조를 가지는 단위 집전체 기공들의 평균 직경은 1 ㎛ 내지 100 ㎛인 것을 특징으로 하는 이차전지용 전극.According to claim 1, The secondary battery electrode, characterized in that the average diameter of the unit current collector pores having the three-dimensional network structure is 1 ㎛ to 100 ㎛.
  6. 제 1 항에 있어서, 상기 단위 전극은 3차원 망상형 구조를 가지는 단위 집전체와 전극 합제가 혼재되어 있는 것을 특징으로 하는 이차전지용 전극.The electrode for secondary batteries according to claim 1, wherein the unit electrode has a unit current collector and an electrode mixture having a three-dimensional network structure.
  7. 제 1 항에 있어서, 상기 단위 집전체의 일측 외면에 코팅되어 있는 전극 합체층의 두께는 10 ㎛ 내지 100 ㎛인 것을 특징으로 하는 이차전지용 전극.The electrode of claim 1, wherein the thickness of the electrode coalescence layer coated on one outer surface of the unit current collector is 10 μm to 100 μm.
  8. 제 1 항에 있어서, 상기 전극의 두께는 50 ㎛ 내지 500 ㎛인 것을 특징으로 하는 이차전지용 전극.The electrode of claim 1, wherein the electrode has a thickness of 50 μm to 500 μm.
  9. 제 1 항에 있어서, 상기 단위 전극들은 전극 합제 중의 바인더에 의해 상호 접합되어 있는 것을 특징으로 하는 이차전지용 전극.The electrode for secondary batteries of claim 1, wherein the unit electrodes are bonded to each other by a binder in the electrode mixture.
  10. 제 1 항에 있어서, 상기 단위 전극들 사이에는 일반 집전체가 추가적으로 개재된 것을 특징으로 하는 이차전지용 전극.The secondary battery electrode of claim 1, wherein a general current collector is additionally interposed between the unit electrodes.
  11. 양극 및 음극과 전해액이 셀 케이스에 내장되어 있고, 상기 양극 및 음극 중의 적어도 하나가 제 1 항 내지 제 10 항 중 어느 하나에 따른 이차전지용 전극으로 이루어진 것을 특징으로 하는 전지셀.A battery cell comprising a positive electrode, a negative electrode, and an electrolyte solution embedded in a cell case, and at least one of the positive electrode and the negative electrode comprises a secondary battery electrode according to any one of claims 1 to 10.
  12. 제 11 항에 있어서, 상기 전해액은 이차전지용 전극에서 단위 집전체의 기공 내로 유입되어 있는 것을 특징으로 하는 전지셀.The battery cell according to claim 11, wherein the electrolyte is introduced into the pores of the unit current collector in the secondary battery electrode.
  13. 제 1 항 내지 제 9 항 중 어느 하나에 따른 이차전지용 전극의 제조방법으로서,A method of manufacturing an electrode for secondary batteries according to any one of claims 1 to 9,
    (a) 3차원 망상형 구조의 단위 집전체 및 전극 슬러리를 준비하는 과정;(a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure;
    (b) 전극 슬러리를 단위 집전체에 코팅하는 과정;(b) coating the electrode slurry on a unit current collector;
    (c) 전극 슬러리를 건조하여 전극 합제층을 형성하는 과정;(c) drying the electrode slurry to form an electrode mixture layer;
    (d) 단위 전극들을 압연하는 과정; 및(d) rolling unit electrodes; And
    (e) 단위 전극들을 적층하는 과정;(e) stacking unit electrodes;
    을 포함하는 것을 특징으로 하는 이차전지용 전극의 제조방법.Method for producing a secondary battery electrode comprising a.
  14. 제 1 항 내지 제 9 항 중 어느 하나에 따른 이차전지용 전극의 제조방법으로서,A method of manufacturing an electrode for secondary batteries according to any one of claims 1 to 9,
    (a) 3차원 망상형 구조의 단위 집전체 및 전극 슬러리를 준비하는 과정;(a) preparing a unit current collector and an electrode slurry of a three-dimensional network structure;
    (b) 전극 슬러리를 단위 집전체에 코팅하는 과정;(b) coating the electrode slurry on a unit current collector;
    (c) 전극 슬러리를 건조하여 전극 합제층을 형성하는 과정;(c) drying the electrode slurry to form an electrode mixture layer;
    (d) 단위 전극들을 적층하는 과정; 및(d) stacking unit electrodes; And
    (e) 적층된 단위 전극들을 압연하는 과정;(e) rolling the stacked unit electrodes;
    을 포함하는 것을 특징으로 하는 이차전지용 전극의 제조방법.Method for producing a secondary battery electrode comprising a.
PCT/KR2017/009672 2016-09-09 2017-09-05 Electrode comprising electrode current collector of three-dimensional network structure WO2018048166A1 (en)

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JP2018547249A JP6723370B2 (en) 2016-09-09 2017-09-05 Electrode including electrode collector having three-dimensional network structure
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US15/774,192 US20180337408A1 (en) 2016-09-09 2017-09-05 Electrode including electrode current collector with three-dimensional network structure
CN201780004251.9A CN108292736B (en) 2016-09-09 2017-09-05 Electrode comprising an electrode current collector having a three-dimensional network structure

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3598526A1 (en) 2018-07-17 2020-01-22 Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. Network of metal fibers, method for producing a network of metal fibers, electrode and battery

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110128433A (en) * 2010-05-24 2011-11-30 주식회사 아모텍 Lithium ion capacitor electrode using fibrous current collector comprising carbon nano fiber, method of manufacturing the same, and lithium ion capacitor using the same
KR20120111508A (en) * 2011-04-01 2012-10-10 주식회사 엘지화학 Electrode current collector for secondary battery and lithium secondary battery comprising the same
KR20130125049A (en) * 2012-05-08 2013-11-18 삼성에스디아이 주식회사 Electrode plate, secondary battery having the same, and manufacturing for the electrode plate
KR20150140619A (en) * 2013-08-05 2015-12-16 주식회사 아모그린텍 Flexible current collector and secondary battery using the same
KR20160062617A (en) * 2014-11-25 2016-06-02 울산과학기술원 Three-dimensional porous-structured current colletor, method of manufacturing the same, electrode including the same, method of manufacturing the same electrode, and electrochemical device including the same current colletor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110128433A (en) * 2010-05-24 2011-11-30 주식회사 아모텍 Lithium ion capacitor electrode using fibrous current collector comprising carbon nano fiber, method of manufacturing the same, and lithium ion capacitor using the same
KR20120111508A (en) * 2011-04-01 2012-10-10 주식회사 엘지화학 Electrode current collector for secondary battery and lithium secondary battery comprising the same
KR20130125049A (en) * 2012-05-08 2013-11-18 삼성에스디아이 주식회사 Electrode plate, secondary battery having the same, and manufacturing for the electrode plate
KR20150140619A (en) * 2013-08-05 2015-12-16 주식회사 아모그린텍 Flexible current collector and secondary battery using the same
KR20160062617A (en) * 2014-11-25 2016-06-02 울산과학기술원 Three-dimensional porous-structured current colletor, method of manufacturing the same, electrode including the same, method of manufacturing the same electrode, and electrochemical device including the same current colletor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3370281A4 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3598526A1 (en) 2018-07-17 2020-01-22 Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. Network of metal fibers, method for producing a network of metal fibers, electrode and battery
WO2020016240A1 (en) 2018-07-17 2020-01-23 MAX-PLANCK-Gesellschaft zur Förderung der Wissenschaften e.V. Network of metal fibers, method for producing a network of metal fibers, electrode and battery
EP4224545A2 (en) 2018-07-17 2023-08-09 Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. Network of metal fibers, method for producing a network of metal fibers, electrode and battery

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