WO2019112395A1 - Liant d'électrode de batterie secondaire, électrode de batterie secondaire et batterie secondaire le comprenant, composition d'électrode de batterie secondaire pour fabrication d'électrode de batterie secondaire, et procédé de fabrication d'électrode de batterie secondaire - Google Patents

Liant d'électrode de batterie secondaire, électrode de batterie secondaire et batterie secondaire le comprenant, composition d'électrode de batterie secondaire pour fabrication d'électrode de batterie secondaire, et procédé de fabrication d'électrode de batterie secondaire Download PDF

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WO2019112395A1
WO2019112395A1 PCT/KR2018/015575 KR2018015575W WO2019112395A1 WO 2019112395 A1 WO2019112395 A1 WO 2019112395A1 KR 2018015575 W KR2018015575 W KR 2018015575W WO 2019112395 A1 WO2019112395 A1 WO 2019112395A1
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Prior art keywords
secondary battery
electrode
battery electrode
copolymer
binder
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PCT/KR2018/015575
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English (en)
Korean (ko)
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김영재
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주식회사 엘지화학
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Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to EP18885044.0A priority Critical patent/EP3703164A4/fr
Priority to CN201880077760.9A priority patent/CN111436221B/zh
Priority to US16/768,988 priority patent/US11600823B2/en
Priority claimed from KR1020180157151A external-priority patent/KR102294865B1/ko
Publication of WO2019112395A1 publication Critical patent/WO2019112395A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F216/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical
    • C08F216/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical by an alcohol radical
    • C08F216/04—Acyclic compounds
    • C08F216/06—Polyvinyl alcohol ; Vinyl alcohol
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/04—Acids; Metal salts or ammonium salts thereof
    • C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts 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
    • H01M4/04—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
    • 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
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a binder for a secondary battery electrode in which a copolymer comprising a unit derived from a polyvinyl alcohol and a unit derived from ionized substituted acrylate is cross-linked, a secondary battery electrode comprising the secondary battery electrode and the secondary battery, And a method for manufacturing the secondary battery electrode.
  • the lithium secondary battery includes a cathode including a cathode active material capable of intercalating / deintercalating lithium ions, a cathode including a cathode active material capable of intercalating / deintercalating lithium ions, an electrode including a microporous separator interposed between the cathode and the anode, Means a battery in which a non-aqueous electrolyte containing lithium ions is contained in an assembly.
  • Lithium metal oxide is used as the positive electrode active material of the lithium secondary battery, and lithium metal, lithium alloy, crystalline or amorphous carbon, carbon composite, and silicon based active material are used as the negative electrode active material.
  • the silicon-based active material is used alone or in combination with other negative electrode active materials in order to improve the capacity of the secondary battery.
  • the electrode structure is changed and the electrode active material or the electrode active material is separated from the current collector, so that the electrode active material is separated or the electrode active material can not function.
  • the electrode is deformed due to damage of the SEI (solid electrolyte interface) membrane due to the volume change of the electrode during charging / discharging, so that lithium existing in the electrolyte is consumed more. This leads to deterioration of the electrode active material and battery due to depletion of the electrolyte. It is to be brought.
  • CMC carboxymethylcellose
  • SBR styrene butadiene rubber
  • the object of the present invention is to provide a binder for a secondary battery electrode capable of effectively controlling the electrode structure change due to volume expansion of the electrode active material during charging and discharging and improving the conductivity of the electrode, A composition for a secondary battery electrode for producing a secondary battery electrode, and a method for manufacturing the secondary battery electrode.
  • the present invention provides a binder for a secondary battery electrode in which a copolymer comprising a unit derived from polyvinyl alcohol and a unit derived from ionized substituted acrylate is crosslinked with each other.
  • the present invention also provides an electrode active material, a conductive material, a copolymer, a crosslinking agent and a solvent, and the copolymer provides a composition for a secondary battery electrode, which is the copolymerization described above.
  • the present invention also provides an active material layer comprising an electrode active material, a conductive material and a binder, wherein the binder is a binder for the secondary battery electrode, and a secondary battery comprising the same.
  • the present invention also provides a method for manufacturing a secondary battery electrode, comprising: coating and drying a composition for a secondary battery electrode as described above; And heat treating the current collector coated with the composition.
  • the electrode structure change due to the volume expansion of the electrode active material can be effectively controlled during charging and discharging, so that the efficiency of the secondary battery can be improved.
  • the conductivity of the electrode can be improved, so that the electrode resistance can be reduced and the output of the cell can be improved.
  • FIG. 1 is a graph showing a result of measurement of a capacity according to discharge rates of a secondary battery manufactured according to Examples and Comparative Examples of the present invention.
  • FIG. 1 is a graph showing a result of measurement of a capacity according to discharge rates of a secondary battery manufactured according to Examples and Comparative Examples of the present invention.
  • FIG. 2 is a graph showing changes in electrode thickness of a secondary battery manufactured according to Examples and Comparative Examples of the present invention.
  • the present invention relates to a binder for a secondary battery electrode, wherein the binder is a binder for a secondary battery electrode in which a copolymer comprising a unit derived from polyvinyl alcohol and a unit derived from ionized substituted acrylate is crosslinked with each other.
  • secondary battery cathodes can be manufactured both in water and non-aqueous systems.
  • carboxymethylcellulose (CMC) and styrene butadiene rubber (SBR) are generally used as binders.
  • CMC carboxymethylcellulose
  • SBR styrene butadiene rubber
  • a negative electrode active material for example, silicon, Tin and oxides thereof
  • the conventional binder alone can not be used for the battery structure due to charging / discharging
  • the change can not be suppressed effectively, and there has been a problem in that deterioration of the battery and deterioration of the life characteristic are caused.
  • the binder when used, there is a problem that the conductive path in the electrode is difficult to secure and the electrode resistance is increased and the output of the battery is reduced.
  • the binder for the secondary battery electrode in which the copolymer comprising the unit derived from polyvinyl alcohol and the unit derived from ionized substituted acrylate according to the present invention are crosslinked is bridged (crosslinked) not only by hydrogen bonding but also by ionic bonding, So that it is excellent in resilience against the volume change of the electrode due to the volume expansion of the electrode active material. Therefore, the initial efficiency of the produced secondary battery can be improved.
  • the binder for the secondary battery electrode may be located between chains connected by hydrogen bonding, the distance between the hydroxyl groups can be appropriately increased. Thus, a conductive path through which lithium ions can move can be ensured, so that the resistance of the produced electrode can be reduced and the output of the secondary battery can be improved.
  • the binder can secure phase stability and adhesion even though it is a single binder, thereby simplifying the manufacturing process.
  • it can increase the solid content of the electrode slurry and suppress the disconnection of the conductive path due to the volume expansion of the electrode active material It is possible to prevent deformation of the electrode even with a change in the volume of the electrode with excellent adhesive force, and to secure excellent charge / discharge life characteristics.
  • the binder since the binder has a unit derived from an ionized substituted acrylate, the adhesive force can be remarkably improved as compared with the case where a unit derived from ionized and non-substituted acrylate is contained.
  • the case where the binder is used has the following effects.
  • CMC carboxymethyl cellulose
  • SBR styrene butadiene rubber
  • the conductive path or network between the electrode active materials is difficult to maintain.
  • the copolymer is present in a state where the binder is partially broken and the remaining amount of the remaining binder capable of acting as a sufficient resistance against the volume expansion is adsorbed on the electrode active material, And serves to suppress the volume expansion of the electrode active material. Also, the conductive path or network between the electrode active materials can thereby be maintained. Thus, the life characteristics of the battery can be improved.
  • the unit derived from the ionized substituted acrylate may be formed by copolymerizing an alkyl acrylate with a monomer and then adding an excess amount of an ionic aqueous solution.
  • the unit derived from acrylate substituted by ionization in the final copolymer structure may be a unit derived from an ionized substituted acrylate, based on the ionized substituted final polymer, irrespective of the acrylate (for example, alkyl acrylate) Can be understood as a unit.
  • the molar fraction of units derived from the ionized substituted acrylate among units excluding units derived from polyvinyl alcohol may be 98 mol% to 100 mol%, specifically 100 mol%.
  • the above-mentioned " 100 mol% " means that all the units other than the units derived from polyvinyl alcohol are units derived from the ionized substituted acrylate, meaning that there is no unit derived from an unsubstituted acrylate do.
  • &quot 98 mol% or more " means that unreacted acrylate-derived units are present when intrinsic acrylate-derived hydrogen is entirely ionized through the above-described substitution process,
  • the content of units derived from the ionized unsubstituted acrylate is only a very small level at an error range level (for example, less than 2 mol%).
  • the unit derived from non-ionized substituted acrylate includes a hydroxyl group (-OH). If the unit derived from the ionized non-substituted acrylate is contained in the copolymer in a large amount, for example, in an amount of 2 mol% or more, crystallization proceeds to a high level due to the hydrogen bonding force after the electrode slurry is dried, The binder produced by crosslinking of the copolymer is excessively easily broken. Accordingly, the amount of the 'unbroken copolymer' which can suppress the volume expansion of the electrode active material is remarkably reduced, and the copolymer adsorbed on the electrode active material is reduced. As a result, the adhesive force between the active material layer and the current collector is lowered, and the life characteristics of the battery are deteriorated.
  • a hydroxyl group -OH
  • the copolymer used in the preparation of the binder of the present invention does not contain units derived from non-ionized substituted acrylate or contains only a low content of less than 2 mol% (error range), wherein the metal cation The degree of crystallinity of the copolymer is lowered to an appropriate level. Therefore, even if some binder is broken during the volume expansion of the electrode active material, the remaining binder is adsorbed to the electrode active material in a state of being not broken, so that the adhesive force between the active material layer and the current collector can be improved, .
  • the molar fraction can be measured as follows. First, GC / MS analysis is carried out on the copolymer using EQC-0107 (Pyrolyzer (PY-2020 / Agilent 6890N GC / 5973N MSD) in powder state) to grasp the exact functional group. Then, solid NMR (Agilent 600 MHz NMR) or solution NMR (Bruker 600 MHz NMR) is carried out to confirm the content ratio of each composition from the peak integral value of the measured graph. In addition, after separating the active material layer from the manufactured electrode and making it into powder form, the mole fraction can be confirmed by performing the above method.
  • the unit derived from polyvinyl alcohol may include a unit represented by the following formula (1).
  • the unit derived from the ionized substituted acrylate includes a unit represented by the following formula (2): wherein, each R may independently be at least one metal cation selected from the group consisting of Na, Li and K.
  • the copolymer may contain from 2000 to 3000 units of the formula (1) and from 1000 to 2000 units of the formula (2).
  • the copolymer may be a block copolymer formed from a unit derived from polyvinyl alcohol and a unit derived from ionized substituted acrylate. That is, a structure in which a unit block derived from polyvinyl alcohol and a unit block derived from ionized acrylate are linearly connected to each other may be a structure constituting a main chain.
  • the unit derived from polyvinyl alcohol and the unit derived from ionized substituted acrylate means a structure in which a polyvinyl alcohol and an acrylate unit having a double bond are formed by an addition reaction, and in the case of acrylate, an ester in the final copolymer structure May not necessarily be the same as the substituent in the starting material.
  • the ionized substituted acrylate may be at least one selected from the group consisting of sodium acrylate and lithium acrylate, and most preferably is at least one selected from the group consisting of sodium acrylate .
  • the alkyl acrylate may be copolymerized with a monomer, and then an excessive amount of sodium ion or lithium ion aqueous solution may be added to replace the monomer.
  • the acrylate-derived unit can be understood as a unit derived from sodium acrylate or a unit derived from lithium acrylate, regardless of the acrylate (for example, alkyl acrylate) used as the raw material.
  • the copolymer may include a unit derived from polyvinyl alcohol and a unit derived from ionized substituted acrylate in a weight ratio of 6: 4 to 8: 2.
  • the polymer is adsorbed on the particles by the polyvinyl alcohol having a hydrophilic group to maintain proper dispersibility, So as to exhibit a stable adhesive force.
  • the formed film may be advantageous in improving battery performance while forming a uniform and dense SEI film during charging / discharging of the battery.
  • the hydrophilic property is weakened, and the solid content soluble in water is decreased, so that the binder tends to float on the surface of the electrode, which affects the performance.
  • the polyvinyl alcohol is contained in an amount larger than the above-mentioned weight ratio range, particles tend to be adsorbed on the bubbles due to intrinsic properties of the PVA during the dissolution or mixing, Non-dispersed gypsum particles are produced, which represent a disadvantage of cell performance and can cause various problems.
  • the weight average molecular weight of the copolymer is less than 100,000, the dispersibility between the binder for the secondary battery electrode is lowered, the possibility of cohesion between the binder is increased, and the charge / discharge life characteristics If it exceeds 500,000, it is difficult to increase the solids content of the slurry because it is difficult to dissolve at a high concentration, and gelation tends to occur during polymerization.
  • the crosslinking may be carried out by an esterification reaction of the copolymer and the crosslinking agent.
  • the -COOR of the copolymer and the crosslinking agent are bonded by an esterification reaction, more specifically, the crosslinking agent comprises two or more glycidyl groups, and each glycidyl group is esterified with -COOR of the copolymer Can be reacted and combined.
  • the binder for the secondary battery electrode may include an ester structure (-COO-), and specifically, the ester structure may exist in a crosslinked chain between the copolymers.
  • the composition for a secondary battery electrode according to an embodiment of the present invention may include an electrode active material, a conductive material, a copolymer, a cross-linking agent, and a solvent.
  • the copolymer is a copolymer containing a unit derived from polyvinyl alcohol and a unit derived from ionized substituted acrylate, and is the same as the above-mentioned copolymer. That is, all of the copolymers that can be derived in the above-described embodiments may correspond to the copolymer included in the composition for the secondary battery electrode.
  • the unit derived from polyvinyl alcohol may include a unit represented by the following formula (1).
  • the unit derived from the ionized substituted acrylate includes a unit represented by the following formula (2): wherein, each R may independently be at least one metal cation selected from the group consisting of Na, Li and K.
  • the copolymer may contain from 2000 to 3000 units of the formula (1) and from 1000 to 2000 units of the formula (2).
  • the composition for the secondary battery electrode may be preferably used in the production of a negative electrode.
  • a carbon-based material lithium metal, silicon, or tin, which can normally store and release lithium ions, may be used.
  • the carbon-based material may be, for example, soft carbon, hard carbon, natural graphite, artificial graphite, kishi graphite (for example, Kish graphite, pyrolytic carbon, mesophase pitch based carbon fiber, mesocarbon microbeads, mesophase pitches and petroleum or coal tar pitch derived. cokes) may be selected from the group consisting of at least one.
  • the electrode active material may further include a Si-based material in the carbon-based material, for example, SiO.
  • the Si-based material may be included in an amount of 5% by weight to 30% by weight based on the total weight of the electrode active material. If the amount of the Si-based material is less than 5% by weight, it may be difficult to realize a high-capacity electrode because the capacity increase depending on the input ratio is not large. When the Si-based material is contained in an amount exceeding 30% by weight, Is too large to deform the electrode, and there is a problem that the life characteristic is remarkably deteriorated.
  • the Si-based material has a high capacity of about 10 times higher than the carbon-based material by about 10 times the theoretical capacity, a high capacity battery can be realized.
  • a change in the crystal structure is caused to cause volume expansion, There is a problem that the lifetime characteristics are deteriorated due to the separation of the active material and the collector and the deformation of the electrode.
  • the conductive material is not particularly limited as long as it can be generally used in the art.
  • artificial graphite, natural graphite, carbon black, acetylene black, ketjen black, denka black, thermal black, channel black A metal selected from the group consisting of aluminum, tin, bismuth, silicon, antimony, nickel, copper, titanium, vanadium, chromium, manganese, iron, cobalt, zinc, molybdenum, tungsten, silver, gold, lanthanum, ruthenium, , Polythiophene, polyacetylene, polypyrrole, or a combination thereof.
  • a carbon black-based conductive material may be used.
  • the solvent may preferably include an aqueous solvent, and the aqueous solvent may include water.
  • the binder according to an embodiment of the present invention may be water-soluble or water-dispersible. However, in some cases, it is possible to use NN-dimethylformamide, NN-dimethylacetamide, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, methyl cellosolve, butyl cell One or more of them may be selected from rosorb, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, diethylene glycol dimethyl ether, toluene and xylene, or they may be used in admixture with water.
  • the content of the solvent is not particularly limited and may be used to make the viscosity of the slurry appropriate.
  • the acrylate-derived unit is in the form of a salt, for example, in the case of sodium acrylate or lithium acrylate, when the binder is dissolved in the solvent, the sodium or lithium cation dissociates or the ionized state May coexist.
  • the composition for the secondary battery electrode may further include an additive for further improving the characteristics.
  • an additive may be a commonly used dispersant, thickener, filler, or the like.
  • Each of these additives may be mixed with the composition for electrodes in preparing the electrode composition beforehand, or separately prepared and used independently.
  • the additive is determined by the electrode active material and the binder component, and may be used in some cases.
  • the electrode composition may be mixed with binders such as carboxymethyl cellulose (CMC) and styrene butadiene rubber (SBR), which have been conventionally used together with the binder of the present invention.
  • CMC carboxymethyl cellulose
  • SBR styrene butadiene rubber
  • the crosslinking agent serves to crosslink the copolymers.
  • the crosslinking agent may be bonded to the -COOR of the copolymer by an esterification reaction.
  • the crosslinking agent may include two or more glycidyl groups, and the ring structure of each glycidyl group is opened ring by a specific heat treatment, and is esterified with -COOR of the copolymer to be combined .
  • the crosslinking agent may include a diglycidyl ether crosslinking agent.
  • the diglycidyl ether-based crosslinking agent is selected from the group consisting of diglycidyl ether, bisphenol A diglycidyl ether, 1,4-butanediol diglycidyl ether and ethylene glycol diglycidyl ether May be at least one selected, and more specifically may be a diglycidyl ether.
  • the molecular weight of the crosslinking agent may be 300 g / mol to 1,000 g / mol, and specifically 400 g / mol to 600 g / mol. If the molecular weight of the crosslinking agent is less than 300 g / mol, the strength of the polymer may not be sufficient and the volume expansion of the electrode may be difficult to control. On the other hand, when the molecular weight exceeds 1,000 g / mol, the cross-linking agent may exist in a solid phase, so that the dispersion of the cross-linking agent in the electrode composition may not be smoothly performed. Therefore, when the above range is satisfied, the appropriate strength of the binder for electrodes and uniform dispersion of the cross-linking agent in the electrode composition can be derived.
  • the weight ratio of the crosslinking agent to the copolymer may be from 1: 4 to 1:20, specifically from 1.6.67 to 1:19, and more specifically from 1: 7.33 to 1: 13.29. If the cross-linking agent is used more than the above-mentioned range, the adhesive strength of the binder in the prepared electrode may be decreased, and the electrode performance may deteriorate. When the crosslinking agent is used less than the above range, crosslinking of the copolymers may not be sufficiently performed.
  • composition for an electrode according to an embodiment of the present invention may contain the copolymer in an amount of 1.8 wt% to 3.3 wt% based on the total weight of solids excluding the solvent.
  • the adhesive strength of the binder is sufficient and the electrode resistance can be at an appropriate level.
  • the secondary battery electrode of the present invention may include an active material layer including an electrode active material, a conductive material, and a binder, and the binder is the same as the binder for the secondary battery electrode described above. Further, the electrode active material and the conductive material are the same as the electrode active material and the conductive material that the composition for the secondary battery electrode described above can include.
  • the electrode active material may be any one selected from the group consisting of softened carbon, cured carbon, natural graphite, artificial graphite, chisel graphite, pyrolytic carbon, liquid crystal pitch carbon fiber, carbon microsphere, liquid crystal pitch, Based carbon material.
  • the electrode active material may further include a Si-based material. Specifically, the Si-based material may be included in an amount of 5% by weight to 30% by weight based on the total weight of the electrode active material.
  • the secondary battery electrode may be a cathode or a cathode, and preferably a cathode.
  • the binder may be included in an amount of 2 wt% to 3.7 wt% based on the total weight of the active material layer, specifically 2.5 wt% to 3.4 wt%, more specifically 2.8 wt% to 3.2 wt%. have.
  • the viscosity of the electrode composition is appropriate and the process can be smooth. Further, since the binder adhesion may be sufficient, the physical properties of the electrode may be improved.
  • the method for manufacturing a secondary battery electrode of the present invention comprises the steps of applying the composition for a secondary battery electrode to a current collector and drying the same; And heat treating the current collector to which the composition is applied.
  • the method for manufacturing the secondary battery electrode may be applied to the manufacture of a negative electrode.
  • the current collector is a metal having a high conductivity and capable of easily adhering to the composition for the secondary battery electrode, and any of them may be used as long as it is not reactive in the voltage range of the battery.
  • the current collector may be a positive current collector or a negative current collector.
  • Non-limiting examples of the positive electrode current collector include aluminum, nickel, or a combination thereof.
  • the negative electrode current collector may be made of copper, gold, nickel, or a copper alloy or a combination thereof. Foil to be manufactured, and the like.
  • the drying may be applied to remove the solvent in the composition for the secondary battery electrode.
  • the heat treatment corresponds to a process for a crosslinking reaction.
  • the heat treatment may be a heat treatment at 90 ° C to 120 ° C, a specific temperature range may be 100 ° C to 120 ° C, and a more specific temperature range may be 110 ° C to 120 ° C. If the heat treatment temperature is lower than 90 ° C, the cross-linking reaction of the copolymers in the composition for electrode may not occur smoothly. If it exceeds 120 ° C, the flexibility of the electrode may be reduced and the mechanical stability may be reduced.
  • the present invention is a lithium secondary battery including a cathode, a cathode, an electrolyte, and a separator.
  • the cathode is the same as the electrode for a secondary battery electrode according to the present invention.
  • the lithium secondary battery of the present invention can be produced by a conventional method known in the art. For example, a separation membrane may be placed between the anode and the cathode, and an electrolyte solution in which a lithium salt is dissolved may be added.
  • the anode may include a cathode active material.
  • the negative electrode may include a negative electrode active material.
  • the negative electrode active material may be a carbon-based material such as lithium metal, silicon, or tin, which is normally capable of occluding and releasing lithium ions, as described in the composition for electrodes of the present invention.
  • the carbon-based material may be mainly used, and the carbon-based material may further include a Si-based material.
  • the negative electrode active material may be the same as the electrode active material included in the composition for a secondary battery electrode of the present invention.
  • the separator included in the lithium secondary battery according to the present invention may be a conventional porous polymer film such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, an ethylene / methacrylate copolymer,
  • a porous polymer film made of the same polyolefin-based polymer may be used alone or in a laminate thereof, or a nonwoven fabric made of a conventional porous nonwoven fabric such as a glass fiber having a high melting point or a polyethylene terephthalate fiber may be used. But is not limited thereto.
  • the electrolytic solution contained in the lithium secondary battery according to the present invention may be at least one selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethylsulfoxide (NMP), ethylmethyl carbonate (EMC), gamma butyrolactone (GBL), fluoroethylene carbonate (FEC), methyl formate (methyl ethyl ketone , At least one mixed organic solvent selected from the group consisting of ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, pentyl acetate, methyl propionate, ethyl propionate, ethyl propionate and butyl propionate.
  • PC propylene carbonate
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • DMC dimethyl carbonate
  • the electrolyte according to the present invention may further include a lithium salt, and the anion of the lithium salt may be an anion selected from the group consisting of F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - ClO 4 -, PF 6 -, (CF 3) 2 PF 4 -, (CF 3) 3 PF 3 -, (CF 3) 4 PF 2 -, (CF 3) 5 PF -, (CF 3) 6 P - , F 3 SO 3 -, CF 3 CF 2 SO 3 -, (CF 3 SO 2) 2 N -, (FSO 2) 2 N -, CF 3 CF 2 (CF 3) 2 CO -, (CF 3 SO 2 ) 2 CH -, (SF 5 ) 3 C -, (CF 3 SO 2) 3 C -, CF 3 (CF 2) 7 SO 3 -, CF 3 CO 2 -, CH 3 CO 2 -,
  • the lithium secondary battery according to the present invention may be a cylindrical, square, or pouch type secondary battery, but is not limited thereto as long as it is a charge / discharge device.
  • the present invention also provides a battery module including the lithium secondary battery as a unit cell and a battery pack including the same.
  • the battery pack includes a power tool; An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); Or a system for power storage.
  • An electric vehicle including an electric vehicle (EV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV); Or a system for power storage.
  • ≪ RTI ID 0.0 > [0027] < / RTI >
  • the weight average molecular weight of the prepared copolymer was 360,000, and the weight ratio of the unit derived from poly (vinylalcohol) and the unit derived from sodium acrylate was 6.7: 3.3.
  • the molar fraction of units derived from the ionized substituted acrylate among the units excluding the unit derived from polyvinyl alcohol was 100 mol%.
  • the mole fractions were determined as follows. First, GC / MS analysis was carried out on the copolymer using EQC-0107 (Pyrolyzer (PY-2020 / Agilent 6890N GC / 5973N MSD) in powder state) to obtain accurate functional groups. Then, solid NMR (Agilent 600 MHz NMR) or solution NMR (Bruker 600 MHz NMR) was carried out, and the content ratio of each composition was confirmed from the peak integral value of the measured graph. As a result, the mole fractions of units derived from ionized substituted acrylate were confirmed.
  • Example 1 Composition for secondary battery electrode, secondary battery Binder for electrode, manufacture of secondary battery and secondary battery
  • the thus-prepared composition for a secondary battery electrode was a mixed solution (solid content: 47.89 wt%) in which a negative electrode active material, a conductive material, a copolymer and a cross-linking agent were mixed at a weight ratio of 96.2: 0.8: 2.7: 0.3.
  • the prepared composition (slurry) for a secondary battery electrode was applied to an anode current collector having a thickness of 20 ⁇ m (mg / cm 2 ) so as to be 5.87 mg per unit area, and dried in a vacuum oven at 70 ° C. for 10 hours. Thereafter, the temperature of the vacuum oven was set at 120 ⁇ and heat treatment was performed for 1 hour. Thus, a binder for a secondary battery electrode was produced in the dried slurry.
  • the positive electrode active material NMC, the carbon black-based conductive material, and the binder PVDF powder were mixed at a weight ratio of 92: 2: 6, respectively, to the solvent N-methyl-2-pyrrolidone to prepare a positive electrode slurry.
  • the prepared positive electrode slurry was applied to a positive electrode current collector having a thickness of 15 ⁇ so as to have an electrode loading (mg / cm 2 ) of 23.4 mg per unit area, dried in a vacuum oven at 120 ⁇ for 10 hours, And rolled at a pressure of 15 MPa to prepare a positive electrode having a final thickness (current collector + active material layer) of 74.0 ⁇ m.
  • the prepared negative electrode and positive electrode and the porous polyethylene separator were assembled by using a stacking method.
  • Example 2 Composition for secondary battery electrode, binder for secondary battery electrode, manufacture of secondary battery electrode, and secondary battery
  • a composition for a secondary battery electrode was prepared in the same manner as in Example 1 except that a total of 94.35 g of the copolymer dispersion was added (3.74 g of total copolymer) and 0.94 g of the crosslinking agent was added.
  • the prepared secondary battery electrode composition was a mixed solution (solid content: 48.0 wt%) in which the anode active material, the conductive material, the copolymer and the cross-linking agent were mixed at a weight ratio of 96.2: 0.8: 2.4: 0.6.
  • a binder for a secondary battery electrode, a secondary battery electrode, and a secondary battery were prepared in the same manner as in Example 1, except that the composition for the secondary battery electrode prepared above was used.
  • the final thickness (collector + active material layer) of the secondary battery electrode was 59.6 mu m, and the loading amount of the active material layer was 153.5 mg / 25 cm < 2 & gt ;.
  • the thus prepared secondary cell electrode composition was a mixed solution (solid content: 47.9 wt%) in which the negative electrode active material, the conductive material and the copolymer were mixed at a weight ratio of 96.2: 0.8: 3.0.
  • the prepared composition (slurry) for a secondary battery electrode was applied to an anode current collector having a thickness of 20 ⁇ m (mg / cm 2 ) so as to be 5.76 mg per unit area, dried in a vacuum oven at 70 ° C. for 10 hours, through a roll heated to 50 °C by rolling under a pressure of 15MPa, and the final thickness (current collector + active material layer) 57.1 ⁇ m, the loading amount of the active material layer was prepared 144.0mg / 25cm 2 of the negative electrode (the secondary battery electrode).
  • CMC carboxymethyl cellulose
  • 1.56 g of carboxymethyl cellulose (CMC, molecular weight: 1,200,000) was added to 140.19 g of water and mixed with a homomixer at a temperature of 40 DEG C and 1500 rpm for 180 minutes to prepare a 1.1 wt% CMC dispersion in which CMC was dispersed.
  • 1.25 g of the carbon black-based conductive material and 27.00 g of water were added to 57.27 g of the dispersion, and the mixture was dispersed with a homomixer.
  • 150.0 g of artificial graphite (negative active material) was added and mixed at 45 rpm for 40 minutes using a Planetary mixer to prepare a slurry.
  • the thus prepared secondary cell electrode composition was a mixed solution (solid content: 44.00 wt%) in which the anode active material, conductive material, and CMC were mixed at a weight ratio of 96.2 / 0.8 / 1.0 / 2.0.
  • the prepared composition (slurry) for a secondary battery electrode was applied to an anode current collector having a thickness of 20 ⁇ m (mg / cm 2 ) so as to be 5.89 mg per unit area, dried in a vacuum oven at 70 ° C. for 10 hours, through a roll heated to 50 °C by rolling under a pressure of 15MPa, and the final thickness (current collector + active material layer) 57.7 ⁇ m, the loading amount of the active material layer was prepared 147.1mg / 25cm 2 of the negative electrode (the secondary battery electrode).
  • the lithium secondary batteries manufactured in Examples 1 and 2 and Comparative Examples 1 and 2 were charged at a constant current (CC) of 1 C under a constant current / constant voltage (CC / CV) condition (battery capacity of 3.4 mAh) After charging until the charge current becomes 0.17 mAh. And discharged at a constant current of 1 C until the voltage reached 1.5 V, followed by 30 cycles. Thereafter, the battery in a fully charged state was disassembled to measure the thickness of the negative electrode, and the electrode thickness increase in comparison with the initial thickness before the cycle is shown in Table 1 and Fig.
  • the electrode thickness increment was calculated as follows.

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Abstract

La présente invention concerne : un liant d'électrode de batterie secondaire ; une électrode de batterie secondaire et une batterie secondaire comprenant celui-ci ; une composition d'électrode de batterie secondaire pour fabriquer l'électrode de batterie secondaire ; et un procédé de fabrication de l'électrode de batterie secondaire. Le liant d'électrode de batterie secondaire peut être un liant pour une électrode de batterie secondaire dans lequel des copolymères comprenant une unité dérivée d'alcool polyvinylique et une unité dérivée d'acrylate substitué par un ion sont liés l'une à l'autre.
PCT/KR2018/015575 2017-12-08 2018-12-07 Liant d'électrode de batterie secondaire, électrode de batterie secondaire et batterie secondaire le comprenant, composition d'électrode de batterie secondaire pour fabrication d'électrode de batterie secondaire, et procédé de fabrication d'électrode de batterie secondaire WO2019112395A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP18885044.0A EP3703164A4 (fr) 2017-12-08 2018-12-07 Liant d'électrode de batterie secondaire, électrode de batterie secondaire et batterie secondaire le comprenant, composition d'électrode de batterie secondaire pour fabrication d'électrode de batterie secondaire, et procédé de fabrication d'électrode de batterie secondaire
CN201880077760.9A CN111436221B (zh) 2017-12-08 2018-12-07 二次电池电极用粘合剂和组合物、二次电池电极和二次电池、以及二次电池电极的制造方法
US16/768,988 US11600823B2 (en) 2017-12-08 2018-12-07 Binder for secondary battery electrode, secondary battery electrode and secondary battery including same, composition for secondary battery electrode for producing said secondary battery electrode, and method for producing said secondary battery electrode

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR20170168639 2017-12-08
KR10-2017-0168639 2017-12-08
KR1020180157151A KR102294865B1 (ko) 2017-12-08 2018-12-07 이차전지 전극용 바인더, 이를 포함하는 이차전지 전극 및 이차전지, 상기 이차전지 전극을 제조하기 위한 이차전지 전극용 조성물, 및 상기 이차전지 전극 제조 방법
KR10-2018-0157151 2018-12-07

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Publication number Priority date Publication date Assignee Title
JPH11250915A (ja) * 1997-11-10 1999-09-17 Nippon Zeon Co Ltd ビニルアルコール系重合体を含有するバインダー、スラリー、および非水電解液二次電池ならびにその電極
KR20140139845A (ko) * 2013-05-28 2014-12-08 삼성에스디아이 주식회사 리튬 이차 전지용 전극, 및 상기 전극을 포함하는 리튬 이차 전지
KR20150131014A (ko) * 2013-03-15 2015-11-24 제온 코포레이션 이차 전지용 바인더 조성물, 이차 전지용 슬러리 조성물, 이차 전지용 부극, 및 이차 전지
KR20170059899A (ko) * 2015-11-23 2017-05-31 주식회사 엘지화학 접착력이 개선된 리튬 이차전지용 전극 및 이의 제조방법
KR20170076592A (ko) * 2015-12-24 2017-07-04 주식회사 엘지화학 이차전지용 바인더 조성물, 및 이를 포함하는 이차전지용 전극 및 리튬 이차전지

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11250915A (ja) * 1997-11-10 1999-09-17 Nippon Zeon Co Ltd ビニルアルコール系重合体を含有するバインダー、スラリー、および非水電解液二次電池ならびにその電極
KR20150131014A (ko) * 2013-03-15 2015-11-24 제온 코포레이션 이차 전지용 바인더 조성물, 이차 전지용 슬러리 조성물, 이차 전지용 부극, 및 이차 전지
KR20140139845A (ko) * 2013-05-28 2014-12-08 삼성에스디아이 주식회사 리튬 이차 전지용 전극, 및 상기 전극을 포함하는 리튬 이차 전지
KR20170059899A (ko) * 2015-11-23 2017-05-31 주식회사 엘지화학 접착력이 개선된 리튬 이차전지용 전극 및 이의 제조방법
KR20170076592A (ko) * 2015-12-24 2017-07-04 주식회사 엘지화학 이차전지용 바인더 조성물, 및 이를 포함하는 이차전지용 전극 및 리튬 이차전지

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