Lithium battery and preparing method thereof

Abstract

A lithium battery comprising a positive electrode; a negative electrode; and a separator interposed between the positive electrode and the negative electrode, the separator comprising a porous substrate and an adhesive layer, wherein the adhesive layer of the separator comprises ceramic particles and a binder in a mixed weight ratio of 4:6 to 6:4, wherein the binder is a polyvinylidene fluoride-based compound, and wherein the binder comprises a first binder and a second binder, wherein the adhesion ratio of the lithium battery is expressed by the following formula 1, and the adhesion ratio is 0.05 to 1.0, and a method for manufacturing the same is provided. Adhesion ratio = {(Dry adhesion - 10N) / (Wet adhesion - 350N)}. In formula 1, the dry adhesion and wet adhesion are defined as in the detailed description.

Description

Technology Field

[0001] This relates to a lithium battery and a method for manufacturing the same. Background Technology

[0002] To meet the demands for miniaturization and high performance in various devices, the miniaturization and lightweighting of lithium batteries are becoming increasingly important. Furthermore, discharge capacity, energy density, and cycle characteristics of lithium batteries are becoming critical for application in fields such as electric vehicles. To meet these requirements, lithium batteries with high discharge capacity per unit volume, high energy density, and excellent lifespan and safety are required.

[0003] A separator is placed between the positive and negative electrodes in a lithium battery to prevent a short circuit. An electrode assembly comprising a positive electrode, a negative electrode, and a separator placed between the positive and negative electrodes is wound to form a jelly roll, and the jelly roll is rolled to improve the adhesion between the positive / negative electrodes and the separator in the electrode assembly.

[0004] To manufacture lithium batteries with excellent safety, a separator with excellent adhesion and heat resistance is required. The problem to be solved

[0005] One aspect is to provide a lithium battery with improved adhesion and heat resistance, and enhanced lifespan characteristics.

[0006] Another aspect is to provide a method for manufacturing the above lithium battery. means of solving the problem

[0007] Depending on one aspect,

[0008] A lithium battery comprising a positive electrode; a negative electrode; and a separator interposed between the positive and negative electrodes, the separator comprising a porous substrate and an adhesive layer, and

[0009] The adhesive layer of the above-mentioned separator comprises ceramic particles and a binder in a mixed weight ratio of 4:6 to 6:4, and

[0010] The above binder is a polyvinylidene fluoride-based compound, and

[0011] The above binder includes a first binder and a second binder, and

[0012] The adhesion ratio of the lithium battery is expressed by the following formula 1, and a lithium battery having an adhesion ratio of 0.05 to 1.0 is provided.

[0013] <Equation 1>

[0014] Adhesion ratio = {(Dry adhesion - 10) / (Wet adhesion - 350)}

[0015] In Formula 1, the wet adhesion strength is 10 to 20 kgf / cm² after impregnating a battery assembly comprising a positive electrode, a negative electrode, and a separator with an electrolyte. 2 This represents the electrode adhesion strength (bending strength) of a separator measured using the 3-point bending method in a lithium battery obtained by pressing under conditions of a temperature of 70 to 90℃ and a time of 1 to 5 minutes.

[0016] The dry adhesion strength of the battery assembly including the anode, cathode, and separator is 10 to 20 kgf / cm 2 This represents the electrode adhesion strength (bending strength) of the separator measured using the 3-point bending method in a lithium battery obtained by pressing under conditions of a temperature of 70 to 90°C and 5 to 20 seconds.

[0017] Depending on the other aspect,

[0018] A step of manufacturing a laminate by laminating an anode; a porous substrate and a separator disposed on one side of the porous substrate; and a cathode; and

[0019] The above laminate is subjected to a pressure of 10 to 20 kgf / cm² 2 A method for manufacturing a lithium battery is provided, comprising the step of pressing under conditions of a temperature of 70 to 90°C and a time of 1 to 5 minutes. Effects of the invention

[0020] According to one aspect, by controlling the composition of the adhesive layer constituting the separator and the press conditions during the manufacture of the battery assembly, it is possible to manufacture a lithium battery with excellent adhesion between the electrode and the separator and improved lifespan characteristics by optimizing dry adhesion and wet adhesion. Brief explanation of the drawing

[0021] Figure 1 is a schematic diagram showing a cross-section of a separator of a lithium battery according to one embodiment. FIG. 2 is a schematic diagram of a lithium battery according to an exemplary embodiment. Specific details for implementing the invention

[0022] A lithium battery and a method for manufacturing the same according to exemplary embodiments will be described in more detail below.

[0023] Recently, there is a demand for separators used in small or medium-to-large lithium batteries that possess excellent wet adhesion to hold the cell shape and dry adhesion for cell assembly processability.

[0024] However, to date, no method has been known to evaluate both wet and dry adhesion of the separator to the electrode, and a separator with excellent wet and dry adhesion has not yet been developed.

[0025] Accordingly, the inventors have completed an invention for a lithium battery having excellent wet adhesion and dry adhesion by controlling the composition of the separator and the press conditions of the separator and the electrode to solve the aforementioned problems. In addition, the present specification provides a method for evaluating the wet adhesion and dry adhesion of the separator and the electrode in a lithium battery by measuring cell strength using 3-point bending.

[0026] The adhesion strength between the electrode and the separator is generally evaluated by a peel test. However, according to this peel test, it is difficult to evaluate wet adhesion strength, and reliability is low because the adhesion strength varies significantly when evaluated by individual sheets, as it is affected by factors such as the flatness of the press equipment.

[0027] However, in a lithium battery according to one embodiment, the adhesion strength can be evaluated by manufacturing a jellyroll-type battery laminate by stacking multiple electrodes and separators and using cell strength through 3-point bending.

[0028] In this specification, the adhesion ratio of the separator constituting the lithium battery to the electrode is represented by the following Formula 1.

[0029] <Equation 1>

[0030] Adhesion ratio = {(Dry adhesion - 10N) / (Wet adhesion - 350N)}

[0031] In Equation 1, wet adhesion is measured by impregnating a battery assembly containing a positive electrode, a negative electrode, and a separator with an electrolyte and pressing it at a specific temperature and pressure to bond the electrode and the separator, thereby measuring the adhesion strength between the electrode and the separator. This wet adhesion is related to the characteristics that hold the cell shape. Dry adhesion is evaluated by pressing a battery assembly containing a positive electrode, a negative electrode, and a separator at a specific temperature and pressure to bond the electrode and the separator, and is related to the cell assembly processability. The electrode adhesion strength (bending strength) of the separator is determined by measuring the adhesion strength between the active material layer of the positive electrode and the separator using the 3-Point Bending (INSTRON) method.

[0032] According to one embodiment, a lithium battery that has undergone a 0.1C charge / discharge step is pressed using a jig at a speed of 5 mm / min to measure the MAX value (N, MPa) from the zero point to 5 mm bending.

[0033] A lithium battery according to one embodiment comprises a positive electrode; a negative electrode; and a separator interposed between the positive electrode and the negative electrode, comprising a porous substrate and an adhesive layer, wherein the adhesive layer of the separator comprises ceramic particles and a binder in a mixed weight ratio of 4:6 to 6:4, wherein the binder is a polyvinylidene fluoride-based compound, and wherein the binder comprises a first binder and a second binder, and the adhesion ratio of the lithium battery is represented by the following formula 1 and has the characteristic of having an adhesion ratio of 0.05 to 1.0.

[0034] <Equation 1>

[0035] Adhesion ratio = {(Dry adhesion - 10N) / (Wet adhesion - 350N)}

[0036] In Formula 1, the wet adhesion strength is 10 to 20 kgf / cm² after impregnating a battery assembly comprising a positive electrode, a negative electrode, and a separator with an electrolyte. 2 This shows the electrode adhesion strength (bending strength) of the separator measured using the 3-point bending method in a lithium battery obtained by pressing under conditions of a temperature of 70 to 90°C and a time of 1 to 5 minutes.

[0037] In Equation 1, the dry adhesion strength-10 is derived from the minimum jelly roll (J / R) strength required for cell assembly, and the wet adhesion strength-350 is derived from the minimum cell strength required to ensure reliability.

[0038] In this specification, the electrolyte comprises a lithium salt and an organic solvent.

[0039] The organic solvent is, for example, propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, methyl propionate, ethyl propionate, propyl propionate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolan, 4-methyldioxolan, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or a mixture thereof. And lithium salts are, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, Li(FSO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F 2x+1 SO2)(C y F 2y+1 The electrolyte is SO2)(where x and y are natural numbers), LiCl, LiI, or a mixture thereof. For example, 1.3 M LiPF6 is dissolved in a 3 / 5 / 2 (volume ratio) mixed solvent of ethylene carbonate (EC) / ethylmethyl carbonate (EMC) / diethyl carbonate (DEC).

[0040] The dry adhesion strength of the battery assembly including the anode, cathode, and separator is 10 to 20 kgf / cm 2 This represents the electrode adhesion strength (bending strength) of the separator measured using the 3-point bending method in a lithium battery obtained by pressing at a temperature of 70 to 90°C for 5 to 20 minutes.

[0041] The adhesion ratio described above is, for example, 0.05 to 1.00, 0.07 to 0.98, 0.09 to 0.96, 0.1 to 0.95, 0.2 to 0.85, or 0.3 to 0.85.

[0042] The above wet adhesive strength is 350 N or more, for example, 350 to 500 N, and the dry adhesive strength is 10 N or more, for example, 10 to 50 N.

[0043] A lithium battery with excellent adhesion between the electrode and the separator can be manufactured when the mixed weight ratio of ceramic particles and the binder is within the above range. Here, the binder is the sum of the first binder and the second binder.

[0044] The first binder is included in an amount of 10 to 50 weight% with respect to the total weight of the first binder and the second binder, and the second binder is included in an amount of 50 to 90 weight% with respect to the total weight of the first binder and the second binder.

[0045] Referring to FIG. 1, a separator (10) for a lithium battery according to one embodiment includes a porous substrate (20) and an adhesive layer (30) located on one or both sides of the porous substrate (20).

[0046] In the adhesive layer (30) of the separator, the ceramic particles are one or more selected from alumina (Al2O3), boehmite, BaSO4, MgO, Mg(OH)2, clay, silica (SiO2), TiO2, ZnO, CaO, SiO2, TiO2, SnO2, CeO2, NiO, GaO, ZrO2, Y2O3, SrTiO3, and BaTiO3. The average size of the ceramic particles is 1 μm to 20 μm, 2 to 15 μm, or 3 to 12 μm.

[0047] In this specification, the average size refers to the average particle size when the ceramic particles are spherical, and the major axis length when the ceramic particles are non-spherical.

[0048] The average particle size refers to the volume-based D50. The average particle size is measured using a measuring device, for example, a laser diffraction method or a dynamic light scattering method. The average particle size is measured using, for example, a laser scattering particle size distribution meter (e.g., Horibasa LA-920), and is the value of the median particle size (D50) when 50% is accumulated from the small particle side in volume conversion.

[0049] In the separator, the binder serves to fix ceramic particles onto a porous substrate while simultaneously providing adhesion to allow the adhesive layer to adhere well to the porous substrate on one side and to the electrode on the other side. The average particle size of the binder is 100 to 300 nm. When the binder has the composition and average particle size described above, the adhesion of the adhesive layer to the porous substrate is excellent. Even when the separator is exposed to high temperatures, the binder has high heat resistance and can maintain a network-like matrix structure.

[0050] The glass transition temperature (Tg) value of the polyvinylidene fluoride-based compounds used as the first binder and the second binder is 50°C or higher, and the weight-average molecular weight of the polyvinylidene fluoride-based compounds is 200,000 to 3,000,000 g / mol, 200,000 to 2,000,000 g / mol, or 300,000 to 1,500,000 g / mol. When the weight-average molecular weight of the polyvinylidene fluoride-based compounds is within the above range, the separator membrane can have excellent adhesion.

[0051] Polyvinylidene fluoride-based compounds are, for example, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trichloroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, or combinations thereof.

[0052] The first binder is a vinylidene fluoride-hexafluoropropylene copolymer. The first binder may include vinylidene fluoride repeating units and hexafluoropropylene repeating units.

[0053] The first binder may further comprise a repeating unit derived from a monomer having at least one hydroxyl group. By further comprising such a repeating unit, the first binder has improved adhesion, durability, and air permeability.

[0054] The monomer having at least one hydroxyl group is one or more selected from the group consisting of (meth)acrylic acid, derivatives of (meth)acrylates having a hydroxyl group, itaconic acid or its derivatives, maleic acid or its derivatives, and hydroxyalkanes allyl ethers.

[0055] The content of repeating units derived from a monomer having at least one hydroxyl group is 0.5 to 10 weight%, or 0.5 to 7 weight%.

[0056] According to one embodiment, the first binder may be included in 80% to 99% by weight of vinylidene fluoride repeating units and 0.5% to 10% by weight of hexafluoropropylene repeating units, and the repeating unit derived from the monomer having at least one hydroxyl group may be included in 0.5% to 10% by weight.

[0057] The first binder may be in various forms, such as an alternating polymer in which the repeating units are alternately distributed, a randomly distributed polymer, or a graft polymer in which some repeating units are grafted. Additionally, the first binder may be a linear polymer, a branched polymer, or a mixture thereof.

[0058] The vinylidene fluoride repeating unit may be included in the first binder in an amount of 90% to 99.5% by weight, 93% to 99% by weight, or 95% to 99% by weight. When the vinylidene fluoride repeating unit is included within the above range, the first binder can secure excellent adhesion and electrolyte impregnation properties.

[0059] The above hexafluoropropylene repeating unit is included in the first binder in an amount greater than 0 wt% and less than or equal to 10 wt%, and within the above range, it may be included in an amount of 0.5 wt% to 10 wt%, 1 wt% to 10 wt%, 1 wt% to 9 wt%, 2 wt% to 7 wt%, or 4 wt% to 6 wt%. When the above hexafluoropropylene repeating unit is included in the above range, the first binder can secure chemical stability and exhibit excellent adhesion while showing excellent solubility in low-boiling point solvents. Accordingly, an adhesive layer can be formed using a low-boiling point solvent without a separate additional process, and a decrease in air permeability that may inevitably occur when using a high-boiling point solvent can be prevented.

[0060] The low boiling point solvent may be, for example, a solvent having a boiling point of about 80°C or lower, and may be, for example, acetone, methyl ethyl ketone, ethyl isobutyl ketone, tetrahydrofuran, dimethylformaldehyde, cyclohexane, or a mixture thereof, but is not limited thereto. For example, the first binder may have a solubility of about 20 or less at 40°C with respect to a solvent having a boiling point of 80°C or lower.

[0061] delete

[0062] The weight average molecular weight of the first binder may be 800,000 to 1,500,000, 800,000 to 1,300,000, or 900,000 to 1,200,000. When the first binder has a weight average molecular weight within the above range, it may exhibit excellent adhesion. The weight average molecular weight may be the polystyrene equivalent average molecular weight measured using gel permeation chromatography.

[0063] The degree of crystallization of the first binder may be 35% to 45%, for example, 38% to 45%, or 40% to 45%. In this case, the first binder may exhibit excellent adhesion. The degree of crystallization of the first binder may be higher than the degree of crystallization of the second binder described later.

[0064] The first binder above can be prepared by various known methods such as emulsion polymerization, suspension polymerization, massive polymerization, solution polymerization, or bulk polymerization, and, for example, can be prepared by suspension polymerization.

[0065] The second binder may include vinylidene fluoride repeating units and hexafluoropropylene repeating units. The second binder may have various forms, such as alternating polymers, random polymers, or graft polymers. The second binder may be a linear polymer, a branched polymer, or a mixture thereof, and may be a polymer having more branched chains than the first binder.

[0066] The vinylidene fluoride repeating unit may be included in the second binder in an amount of 90% to 99.5% by weight, 93% to 99% by weight, or 95% to 99% by weight. When the vinylidene fluoride repeating unit is included within the above range, the second binder can secure excellent adhesion and electrolyte impregnation properties.

[0067] The hexafluoropropylene repeating unit is included in the second binder in an amount greater than 0 wt% and less than or equal to 10 wt%, and within the above range, it may be included in an amount of 0.5 wt% to 10 wt%, 1 wt% to 9 wt%, 2 wt% to 8 wt%, 3 wt% to 7 wt%, or 4 wt% to 6 wt%. When the hexafluoropropylene repeating unit is included in the above range, the second binder can secure chemical stability and exhibit excellent adhesion while showing excellent solubility in a low-boiling point solvent. Accordingly, the adhesion layer (30) can be formed using a low-boiling point solvent without a separate additional process, and the decrease in air permeability that may inevitably occur when using a high-boiling point solvent can be prevented.

[0068] The weight average molecular weight of the second binder may be 600,000 or less, 550,000 or less, 500,000 or less, for example, 500 to 500,000, 1,000 to 500,000, 10,000 to 500,000, 100,000 to 500,000, 200,000 to 500,000, 300,000 to 500,000, or 3,500,000 to 500,000. When the second binder has a weight average molecular weight within the above range, the adhesive layer (30) containing it may exhibit excellent wet adhesion and dry adhesion. The weight average molecular weight may be the polystyrene equivalent average molecular weight measured using gel permeation chromatography.

[0069] The degree of crystallization of the second binder is 35% to 45%, for example, 35% to 40%, or 35% to 37%. When the second binder has a degree of crystallization within the above range, the adhesive layer (30) containing it exhibits excellent dry adhesion. The degree of crystallization of the second binder can be said to be lower than the degree of crystallization of the first binder described above.

[0070] The second binder can be manufactured by various known methods, such as emulsion polymerization, suspension polymerization, bulk polymerization, solution polymerization, or bulk polymerization, and, for example, can be manufactured by emulsion polymerization.

[0071] The separator (10) can exhibit excellent heat resistance, stability, wet adhesion, and dry adhesion by including an adhesive layer (30) containing the ceramic particles and binder described above.

[0072] The content of ceramic particles in the adhesive layer is 40 to 60 parts by weight based on 100 parts by weight of the total weight of the adhesive layer, and the content of the binder is 40 to 60 parts by weight. When the content of ceramic particles and binder in the adhesive layer is within the above range, the heat resistance of the adhesive layer is improved, so that the separator membrane can be prevented from rapidly shrinking or deforming due to a rise in temperature.

[0073] The thickness of the adhesive layer is 0.01㎛ to 20㎛, 1㎛ to 10㎛, or 1㎛ to 5㎛. Excellent adhesion is exhibited when the thickness of the adhesive layer is within the above range.

[0074] The porous substrate included in the separator may be a polyolefin-based substrate containing polyolefin, and the polyolefin-based substrate may contribute to improving the safety of the battery by having excellent shutdown function. The polyolefin-based substrate may be selected from, for example, a polyethylene single membrane, a polypropylene single membrane, a polyethylene / polypropylene double membrane, a polypropylene / polyethylene / polypropylene triple membrane, and a polyethylene / polypropylene / polyethylene triple membrane. In addition, the polyolefin-based resin may include a non-olefin resin in addition to the olefin resin, or may include a copolymer of an olefin and a non-olefin monomer.

[0075] The thickness of the porous substrate is 1 μm to 100 μm, 1 to 40 μm, 1 μm to 30 μm, 5 μm to 20 μm, 5 μm to 15 μm, or 5 μm to 10 μm. If the thickness of the porous substrate is less than 1 μm, it may be difficult to maintain the mechanical properties of the separator, and if the thickness of the porous substrate is greater than 100 μm, the internal resistance of the lithium battery may increase. The porosity of the porous substrate included in the separator may be 5% to 95%. If the porosity is less than 5%, the internal resistance of the lithium battery may increase, and if the porosity is greater than 95%, it may be difficult to maintain the mechanical properties of the porous substrate. The pore size of the porous substrate in the separator may be 0.01 μm to 50 μm, 0.01 μm to 20 μm, or 0.01 μm to 10 μm. If the pore size of the porous substrate is less than 0.01㎛, the internal resistance of the lithium battery may increase, and if the pore size of the porous substrate is greater than 50㎛, it may be difficult to maintain the mechanical properties of the porous substrate.

[0076] Any method for manufacturing the above-described separation membrane that can be used in the relevant technical field is possible. For example, it can be manufactured by a process such as preparing a slurry containing organic particles, a first binder, and optionally inorganic particles, applying it onto a porous substrate, drying, and rolling.

[0077] The method of applying the above slurry is not particularly limited and any method that can be used in the relevant technical field is possible. For example, it can be formed by methods such as printing, compression, press-fitting, roller application, blade application, brush application, dipping application, spray application, or flow application.

[0078] A lithium battery according to another embodiment includes a positive electrode, a negative electrode, and the aforementioned separator disposed between the positive electrode and the negative electrode. According to one embodiment, the lithium battery includes an electrode assembly comprising a positive electrode, a negative electrode, and the aforementioned separator disposed between the positive electrode and the negative electrode, and the electrode assembly may have a form wound in the shape of a jelly roll. Since the lithium battery includes the aforementioned separator, the adhesion between the electrodes (positive and negative electrodes) and the separator is increased, so the volume change during charging and discharging of the lithium battery can be suppressed. Accordingly, the degradation of the lithium battery accompanying the volume change of the lithium battery is suppressed, and the lifespan characteristics of the lithium battery can be improved.

[0079] Lithium batteries can be manufactured, for example, in the following ways.

[0080] First, a negative electrode active material composition is prepared by mixing a negative electrode active material, a conductive material, a binder, and a solvent. The negative electrode active material composition is directly coated onto a metal current collector to manufacture a negative electrode plate. Alternatively, the negative electrode active material composition may be cast onto a separate support, and then a film peeled from the support is laminated onto a metal current collector to manufacture a negative electrode plate. The negative electrode is not limited to the forms listed above and may be in a form other than those listed above.

[0081] The cathode active material includes carbon-based materials.

[0082] Carbon-based materials may be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may be non-shaped, plate-like, flake-like, natural graphite, artificial graphite, graphene, carbon black, fullerene soot, or a combination thereof.

[0083] Natural graphite is graphite that occurs naturally and includes flake graphite, high-crystalline graphite, and microcrystalline (or cryptocrystalline; amorphous) graphite. Artificial graphite is graphite that is artificially synthesized; it is produced by heating amorphous carbon to high temperatures and includes primary or electrographite, secondary graphite, and graphite fiber. Expanded graphite is produced by intercalating chemicals such as acids or alkalis between the layers of graphite and heating it to expand the vertical layers of the molecular structure. Graphene contains a single layer or multiple single layers of graphite. Carbon black is a crystalline material with less regularity than graphite, and carbon black can transform into graphite if heated at approximately 3,000°C for a long time. Fullerene soot is a carbon mixture containing at least 3 weight percent of fullerene, which is a polyhedral bundle-shaped compound composed of 60 or more carbon atoms. The above crystalline carbon may have a spherical, plate-like, fibrous, tubular, or powder form.

[0084] The above amorphous carbon may be soft carbon (low-temperature calcined carbon) or hard carbon, mesophase pitch carbide, calcined coke, polymer carbide, or a combination thereof.

[0085] The negative electrode active material may further include non-carbon-based materials. For example, the negative electrode active material may include one or more selected from the group consisting of a metal capable of forming an alloy with lithium, an alloy of a metal capable of forming an alloy with lithium, and an oxide of a metal capable of forming an alloy with lithium.

[0086] For example, the metals that can be alloyed with the lithium may be Si, Sn, Al, Ge, Pb, Bi, Sb Si-Y alloys (wherein Y is an alkali metal, alkaline earth metal, group 13–16 element, transition metal, rare earth element, or a combination thereof, and is not Si), Sn-Y alloys (wherein Y is an alkali metal, alkaline earth metal, group 13–16 element, transition metal, rare earth element, or a combination thereof, and is not Sn), etc. The element Y may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0087] For example, the transition metal oxide may be lithium titanium oxide, vanadium oxide, lithium vanadium oxide, etc.

[0088] For example, the above non-transfer metal oxides are SnO2, SiO2 x (0 <x<2) 등일 수 있다.

[0089] Specifically, the above negative electrode active material is Si, Sn, Pb, Ge, Al, SiOx(0 <x≤2), SnOy(0<y≤2), Li4Ti5O 12 It may be one or more selected from the group consisting of TiO2, LiTiO3, and Li2Ti3O7, but is not necessarily limited to these, and any non-carbon-based negative electrode active material used in the relevant technical field is acceptable.

[0090] According to one embodiment, the cathode active material may be a mixture of the carbon-based material and the non-carbon-based material described above, or a composite containing the carbon-based material and the non-carbon-based material described above.

[0091] As conductive materials, acetylene black, ketjenblack, natural graphite, artificial graphite, carbon black, acetylene black, ketjenblack, carbon fiber, metal powders such as copper, nickel, aluminum, and silver, metal fibers, etc., may be used, and one or more types of conductive materials such as polyphenylene derivatives may be used in combination, but are not limited to these, and any material that can be used as a conductive material in the relevant technical field may be used. In addition, the aforementioned crystalline carbon-based material may be added as a conductive material.

[0092] As a binder, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene and mixtures thereof, or styrene butadiene rubber-based polymer may be used, but are not limited to these, and any that can be used as a binder in the relevant technical field may be used.

[0093] As a solvent, N-methylpyrrolidone, acetone, or water may be used, but is not limited to these, and any solvent that can be used in the relevant technical field may be used.

[0094] The content of the negative electrode active material, conductive material, binder, and solvent is at a level typically used in lithium batteries. Depending on the application and composition of the lithium battery, one or more of the conductive material, binder, and solvent may be omitted.

[0095] Meanwhile, the binder used in the above cathode manufacturing may be the same as the coating composition included in the adhesive layer of the separator.

[0096] Next, a positive active material composition is prepared by mixing a positive active material, a conductive material, a binder, and a solvent. The positive active material composition is directly coated and dried onto a metal current collector to manufacture a positive plate. Alternatively, the positive active material composition may be cast onto a separate support, and then a film peeled from the support is laminated onto a metal current collector to manufacture a positive plate.

[0097] As a positive electrode active material, it may include one or more selected from the group consisting of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, and lithium manganese oxide, but is not necessarily limited to these, and any positive electrode active material available in the relevant technical field may be used.

[0098] For example, Li a A 1-b B b D2(wherein 0.90 ≤ a ≤ 1.8, and 0 ≤ b ≤ 0.5); Li a E 1-b B b O 2-c D c (In the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE 2-b B b O 4-c D c (In the above equation, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B c D α (In the above equation, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Co b B c O 2-α F α (In the above equation, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Lia Ni 1-b-c Co b B c O 2-α F2(wherein, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c D α (In the above equation, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Mn b B c O 2-α F α (In the above equation, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c O 2-α F2(wherein, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni b E c G d O2(wherein 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li a Ni b Co c Mn d GeO2(wherein the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li a NiG b O2(in the above equation, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a CoG bO2(in the above equation, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a MnG b O2(in the above equation, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4(wherein 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3-f) J2(PO4)3(0 ≤ f ≤ 2); Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2); compounds represented by any one of the chemical formulas of LiFePO4 may be used:

[0099] In these chemical formulas, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0100] Of course, a coating layer on the surface of this compound may be used, or a mixture of the compound and a compound having a coating layer may be used. This coating layer may include a coating element compound of an oxide, hydroxide, oxyhydroxide, oxycarbonate, or hydroxycarbonate of a coating element. The compounds forming this coating layer may be amorphous or crystalline. As coating elements included in the coating layer, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof may be used. For the coating layer formation process, any coating method may be used as long as the compound can be coated using these elements in a way that does not adversely affect the physical properties of the cathode active material (e.g., spray coating, immersion method, etc.). Since this is a matter that is well understood by those skilled in the art, a detailed explanation will be omitted.

[0101] For example, LiNiO2, LiCoO2, LiMn x O 2x (x=1, or 2), LiNi 1-x Mn x O2(0 <x<1), LiNi 1-x-y Co x Mn y O2 (0≤x≤0.5, 0≤y≤0.5), LiFeO2, V2O5, TiS, MoS, etc. can be used.

[0102] In the positive electrode active material composition, the conductive material, binder, and solvent may be the same as those used in the negative electrode active material composition. Meanwhile, it is also possible to form pores inside the electrode plate by further adding a plasticizer to the positive electrode active material composition and / or the negative electrode active material composition.

[0103] The content of the cathode active material, conductive material, general binder, and solvent is at a level typically used in lithium batteries. Depending on the application and composition of the lithium battery, one or more of the above conductive material, general binder, and solvent may be omitted.

[0104] Meanwhile, the binder used in the manufacture of the anode may be the same as the adhesive layer composition included in the adhesive layer of the separator.

[0105] Next, the aforementioned separator is placed between the anode and the cathode.

[0106] In an electrode assembly comprising an anode, a separator, and a cathode, the separator disposed between the anode and the cathode comprises a porous substrate as described above; and an adhesive layer disposed on both sides of the porous substrate, wherein the adhesive layer comprises the coating composition for the separator described above.

[0107] The separator may be prepared separately and placed between the positive and negative electrodes. Alternatively, the separator may be prepared by undergoing a formation step in which an electrode assembly comprising a positive electrode, a separator, and a negative electrode is wound into a jelly roll, the jelly roll is placed in a battery case or pouch, the jelly roll is thermally softened under pressure while placed in the battery case or pouch and pre-charged, the charged jelly roll is hot-rolled, the charged jelly roll is cold-rolled, and the charged jelly roll is charged and discharged under pressure.

[0108] Next, the electrolyte is prepared.

[0109] Electrolytes can be in a liquid or gel state.

[0110] For example, the electrolyte may be an organic electrolyte. Additionally, the electrolyte may be a solid. For example, it may be boron oxide, lithium oxynitride, etc., but is not limited to these; any material that can be used as a solid electrolyte in the relevant technical field may be used. The solid electrolyte may be formed on the cathode by a method such as sputtering.

[0111] For example, an organic electrolyte can be prepared. The organic electrolyte can be prepared by dissolving a lithium salt in an organic solvent.

[0112] Any organic solvent that can be used as an organic solvent in the relevant technical field may be used. Examples include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, methyl propionate, ethyl propionate, propyl propionate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or mixtures thereof.

[0113] Any lithium salt that can be used as a lithium salt in the relevant technical field may also be used. For example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, Li(FSO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2)(where x and y are natural numbers), LiCl, LiI, or a mixture thereof.

[0114] As an example of a lithium battery, a prismatic lithium secondary battery is described. FIG. 2 is an exploded perspective view of a lithium battery according to one embodiment.

[0115] Referring to FIG. 2, a lithium secondary battery (100) according to one embodiment includes an electrode assembly (60) wound with a separator (10) interposed between a positive electrode (40) and a negative electrode (50), and a case (70) in which the electrode assembly (60) is housed.

[0116] The electrode assembly (60) may be in the form of a jelly roll formed by winding the positive electrode (40) and the negative electrode (50) with the separator (10) in between.

[0117] The positive electrode (40), the negative electrode (50), and the separator (10) are impregnated with an electrolyte (not shown).

[0118] The above lithium battery may be a lithium-ion battery. The above lithium battery may be a lithium-polymer battery.

[0119] Lithium batteries are suitable for electric vehicles (EVs) due to their excellent high-rate and lifespan characteristics. For example, they are suitable for hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs).

[0120] The creative concept is explained in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the creative concept and do not limit the scope of the creative concept to these examples alone.

[0121] (Manufacturing of lithium batteries)

[0122] Example 1

[0123] (Manufacturing of separator membranes)

[0124] 6 parts by weight of ceramic particles Al2O3 (ASES-11, Sumitomo Corporation), 4 parts by weight of binder, and

[0125] A composition for forming an adhesive layer was prepared by mixing 90 parts by weight of acetone as a solvent. A binder was prepared by mixing a first binder with a weight-average molecular weight of 1,120,000, prepared by suspension polymerization of 93.5 wt% vinylidene fluoride, 5 wt% hexafluoropropylene, and 1.5 wt% acrylic acid, and a second binder with a weight-average molecular weight of 450,000, prepared by emulsion polymerization of 95 wt% vinylidene fluoride and 5 wt% hexafluoropropylene, in a weight ratio of 5:5 in an acetone solvent.

[0126] A separator was manufactured by gravure printing the above adhesive layer forming composition onto one side of a polyethylene porous substrate (SK Innovation, PE) with a thickness of 7.5 μm to form an adhesive layer with a thickness of 3.0 μm on one side of the polyethylene porous substrate.

[0127] (Manufacturing of the cathode)

[0128] The cathode was manufactured according to the following process.

[0129] A cathode active material slurry was prepared by mixing 97 wt% of graphite particles with an average particle size of 25 μm, 1.5 wt% of styrene-butadiene rubber (SBR) binder, and 1.5 wt% of carboxymethylcellulose (CMC), adding the mixture to distilled water, and stirring for 60 minutes using a mechanical stirrer. The slurry was applied onto a copper current collector with a thickness of 10 μm using a doctor blade, dried in a hot air dryer at 100°C for 0.5 hours, dried once more under vacuum conditions at 120°C for 4 hours, and then rolled to produce a cathode.

[0130] (Manufacturing of the anode)

[0131] Separately, the anode was manufactured according to the following process.

[0132] A cathode active material slurry was prepared by mixing 97 wt% LiCoO2, 1.5 wt% carbon black powder as a conductive material, and 5 wt% polyvinylidene fluoride, adding the mixture to an N-methyl-2-pyrrolidone solvent, and stirring for 30 minutes using a mechanical stirrer. The slurry was applied onto a 20 μm thick aluminum current collector using a doctor blade, dried in a hot air dryer at 100°C for 0.5 hours, dried again under vacuum conditions at 120°C for 4 hours, and then rolled to produce a cathode plate.

[0133] (Electrode assembly jelly roll)

[0134] An electrode assembly jelly roll was prepared by interposing the separator between the anode and cathode plates manufactured above and then winding it. The jelly roll was inserted into a pouch, an electrolyte was injected, and then the pouch was vacuum-sealed.

[0135] The electrolyte used was 1.3 M LiPF6 dissolved in a 3 / 5 / 2 (volume ratio) mixed solvent of ethylene carbonate (EC) / ethylmethyl carbonate (EMC) / diethyl carbonate (DEC).

[0136] 11.7 kgf / cm² in the jelly roll inserted in the pouch 2 A lithium battery was manufactured by applying pressure and pressing at a temperature of 80°C for 3 minutes.

[0137] Example 2

[0138] A separator and a lithium battery were manufactured according to the same method as in Example 1, except that the content of ceramic particles was changed to 4 parts by weight and the content of binder to 6 parts by weight when preparing the composition for forming the adhesive layer.

[0139] Example 3

[0140] A separator and a lithium battery were manufactured according to the same method as in Example 1, except that the ratio of the first binder to the second binder was changed to 7:3 when preparing the composition for forming the adhesive layer.

[0141] Comparative Example 1

[0142] A separator and a lithium battery were manufactured according to the same method as in Example 1, except that the ratio of the first binder to the second binder was changed to 10:0 when preparing the composition for forming the adhesive layer.

[0143] Comparative Example 2

[0144] A separator and a lithium battery were manufactured according to the same method as in Example 1, except that when preparing the composition for forming an adhesive layer, the content of ceramic particles was changed to 2 parts by weight and the content of binder was changed to 8 parts by weight, and the ratio of the first binder to the second binder was changed to 10:0.

[0145] Comparative Example 3

[0146] A separator and a lithium battery were manufactured by following the same method as in Example 1, except that when preparing the composition for forming an adhesive layer, the content of ceramic particles was changed to 7.5 parts by weight and the content of binder was changed to 2.5 parts by weight, and the ratio of the first binder to the second binder was changed to 10:0.

[0147] Comparative Example 4

[0148] A separator and a lithium battery were manufactured by following the same method as in Example 1, except that when preparing the composition for forming an adhesive layer, the content of ceramic particles was changed to 7 parts by weight and the content of binder to 3 parts by weight, and the ratio of the first binder to the second binder was changed to 0:10.

[0149] The above lithium battery exhibited poor charge and discharge characteristics.

[0150] Evaluation Example 1: Adhesion Strength Evaluation

[0151] Wet adhesion and dry adhesion were measured for lithium batteries prepared according to Examples 1 to 3 and Comparative Examples 1 and 5, respectively, and the adhesion ratio was calculated using these values ​​and is shown in Table 1 below. The adhesion ratio can be expressed by the following Equation 1.

[0152] (1) Wet adhesion

[0153] A battery assembly comprising a positive electrode, a negative electrode, and a separator is impregnated with an electrolyte, and then the assembly is impregnated with 10 to 20 kgf / cm² 2 This shows the electrode adhesion strength (bending strength) of the separator measured using the 3-point bending method in a lithium battery obtained by pressing under conditions of a temperature of 70 to 90°C and a time of 1 to 5 minutes.

[0154] A battery assembly in the form of a jelly roll was prepared by interposing the separator prepared in Example 1 between the anode and cathode prepared in Example 1 and then winding it. The jelly roll was inserted into a pouch, an electrolyte was injected, and then the pouch was vacuum-sealed.

[0155] The electrolyte used was 1.3 M LiPF6 dissolved in a 3 / 5 / 2 (volume ratio) mixed solvent of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC). The jellyroll battery assembly inserted into a pouch was tested at 80°C and 11.7 kgf / cm² 2 , performed a press for 180 seconds.

[0156] (2) Dry adhesive power

[0157] A battery assembly comprising a positive electrode, a negative electrode, and a separator at a pressure of 10 to 20 kgf / cm² 2 This represents the electrode adhesion strength (bending strength) of the separator measured using the 3-point bending method in a lithium battery obtained by pressing under conditions of a temperature of 70°C to 90°C and a time of 5 to 20 seconds.

[0158] A battery assembly in the form of a jelly roll was prepared by interposing the separator prepared in Example 1 between the anode and cathode prepared in Example 1 and then winding it. The battery assembly was inserted into a pouch, an electrolyte was injected, and then the pouch was vacuum sealed.

[0159] 85℃, 11.7kgf / cm² for the battery assembly inserted in the pouch 2 Pressing was performed for 10 seconds, and the electrode adhesion (bending strength) of the separator was evaluated using the 3-point bending method.

[0160] The electrode adhesion (bending strength) of the separator was measured using the 3-point bending (INSTRON) method to determine the adhesion between the active material layer of the anode and the separator. A pouch cell that had undergone a 0.1C charge / discharge step was pressed using a jig at a speed of 5 mm / min, and the maximum value (N, MPa) was measured from the zero point to 5 mm bending. The evaluation conditions for the 3-point bending (INSTRON) method are as follows.

[0161] Lower Span Width: 27mm, Lower Span Diameter: 5mm

[0162] Upper jig diameter: 5mm, Load cell: 1000N

[0163] <Equation 1>

[0164] Adhesion ratio = {(Dry adhesion - 10) / (Wet adhesion - 350)}

[0165] division Ceramic particle content (parts by weight) Binder content (parts by weight) Wet adhesion bending strength (N) Dry adhesive strength bending strength (N) Adhesion ratio Example 1 6 4 380 38 0.933 Example 2 4 6 450 44 0.340 Example 3 6 4 450 15 0.050 Comparative Example 1 6 4 420 13 0.043 Comparative Example 2 2 8 700 11 0.003 Comparative Example 3 7.5 2.5 400 8 -0.040 Comparative Example 4 7 3 270 32 -0.275

[0166] Referring to Table 1, the lithium batteries of Examples 1 to 3 showed excellent wet adhesion and dry adhesion, and the adhesion ratio of the separator was found to be very superior compared to the separators of Comparative Examples 1 to 4.

[0167] Evaluation Example 2: Life Characteristics

[0168] In the lithium batteries prepared according to Examples 1 to 3 and Comparative Examples 1 to 4, the charge / discharge characteristics, etc. were evaluated using a charge / discharger (Manufacturer: TOYO, Model: TOYO-3100).

[0169] For the life evaluation, constant current charging was performed at 1C until 4.4 V was reached, followed by constant voltage charging until 0.05C was reached. After the charging was complete, the cell was evaluated by repeating a cycle of constant current discharge at 1C until the voltage reached 3 V 500 times, after a rest period of about 10 minutes.

[0170] The results of the life evaluation are shown in Table 2 below. In the life characteristics of Table 2 below, OK indicates a capacity of >80% and NG indicates a capacity of <80%.

[0171] Evaluation Example 3: Heat Exposure

[0172] The thermal exposure characteristics of the separator prepared according to Examples 1 to 3 and Comparative Examples 1 to 4 are evaluated after 24 hours of charging from a discharge state of 3.0V to 4.4V at a charging rate of 0.5C with a 0.05C cutoff condition.

[0173] The temperature of the evaluation chamber was increased from room temperature to 137°C at a rate of 5°C / min, and once it reached 137°C, it was maintained for 1 hour, after which the oven temperature was returned to room temperature and the test was terminated. At this time, the condition of the battery was evaluated. In Table 2 below, 0F / 10 indicates that 0 out of 10 evaluations failed, which is indicated as "OK," and 1F / 10 indicates that 1 out of 10 evaluations failed, which is indicated as "NG."

[0174] division Ceramic particle content (parts by weight) Binder content (parts by weight) Assembly processability Lifespan characteristics (%)(>85%@500cy) Heat exposure (137℃) Example 1 6 4 OK 91 OK(0F / 10) Example 2 4 6 OK 89 OK(0F / 10) Example 3 6 4 OK 92 OK(0F / 10) Comparative Example 1 6 4 OK 90 NG(1F / 10) Comparative Example 2 2 8 NG NG OK(0F / 10) Comparative Example 3 7.5 2.5 NG 90 NG(2F / 10) Comparative Example 4 7 3 OK 28@200cycle NG(7F / 10)

[0175] Referring to Table 2, it was found that the lifespan characteristics of the lithium batteries of Examples 1 to 3 were significantly improved compared to the lithium batteries of Comparative Examples 2 and 4. Although the lithium battery of Comparative Example 2 had excellent thermal exposure characteristics, as shown in Table 1 above, the adhesion ratio was less than 0.05, resulting in poor assembly processability and lifespan characteristics of the cell.

[0176] As shown in Table 2, the separator of Comparative Example 1 had excellent assembly processability and degraded thermal exposure characteristics, while the separator of Comparative Example 3 had degraded assembly processability and thermal exposure characteristics. Additionally, it was found that using the separator of Comparative Example 4 resulted in significantly reduced lifespan characteristics and degraded thermal exposure characteristics.

[0177] Although one embodiment has been described above with reference to the drawings and examples, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the scope of protection of the present invention should be determined by the appended claims. Explanation of the symbols

[0178] 10: Separator 20: Porous substrate 30: Adhesive layer 40: Anode 50: Cathode 60: Electrode assembly 70: Case

Claims

Claim 1 Positive electrode; negative electrode; A lithium battery comprising a separator interposed between a positive electrode and a negative electrode, the separator comprising a porous substrate and an adhesive layer, wherein the adhesive layer of the separator comprises ceramic particles and a binder in a mixed weight ratio of 4:6 to 6:4, the binder is a polyvinylidene fluoride-based compound, the binder comprises a first binder and a second binder, the first binder is a copolymer comprising vinylidene fluoride repeating units and hexafluoropropylene repeating units, the content of the hexafluoropropylene repeating units is 10 weight% or less, and the weight-average molecular weight of the first binder is 800,000 to 1,500,000, the second binder is a copolymer comprising vinylidene fluoride repeating units and hexafluoropropylene repeating units, the content of the hexafluoropropylene repeating units is 10 weight% or less, and the weight-average molecular weight of the second binder is 600,000. The following applies, wherein the adhesion ratio of the lithium battery is expressed by the following Formula 1, the adhesion ratio is 0.05 to 1.0, the polyvinylidene fluoride-based compound has a glass transition temperature (Tg) value of 50°C or higher, the polyvinylidene fluoride-based compound is polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-trichloroethylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-acrylic acid copolymer, or a combination thereof, and the mixing weight ratio of the first binder and the second binder is 5:5 to 7:3, lithium battery: <Formula 1> Adhesion ratio = {(Dry adhesion - 10N) / (Wet adhesion - 350N)} in Formula 1, wherein the wet adhesion is to a battery assembly including a positive electrode, a negative electrode, and a separator After impregnating with electrolyte, 10~20 kgf / cm² 2 It represents the electrode adhesion strength (bending strength, N) of the separator measured using the 3-point bending method in a lithium battery obtained by pressurizing under conditions of pressure, temperature of 70–90°C, and time of 1–5 minutes, and the dry adhesion strength is 10–20 kgf / cm² after impregnating the battery assembly including the positive electrode, negative electrode, and separator with an electrolyte. 2 This represents the electrode adhesion strength (bending strength, N) of the separator measured using the 3-point bending method in a lithium battery obtained by pressurizing under pressure conditions. Claim 2 A lithium battery according to claim 1, wherein the adhesive strength ratio is 0.10 to 0.

95. Claim 3 delete Claim 4 In claim 1, the ceramic particles are alumina (Al2O3), boehmite, BaSO4, MgO, Mg(OH)2, clay, silica (SiO2), TiO2, ZnO, CaO, SiO2, TiO2, SnO2, CeO2, NiO, GaO, ZrO2, Y2O3, SrTiO3 and A lithium battery selected from one or more of BaTiO3. Claim 5 A lithium battery according to claim 1, wherein the content of ceramic particles in the adhesive layer is 40 to 60 parts by weight based on 100 parts by weight of the total weight of the adhesive layer. Claim 6 A lithium battery according to claim 1, wherein the binder content in the adhesive layer is 40 to 60 parts by weight based on 100 parts by weight of the total weight of the adhesive layer. Claim 7 delete Claim 8 A lithium battery according to claim 1, wherein the wet adhesion strength is 350 N or more and the dry adhesion strength is 10 N or more. Claim 9 A step of manufacturing a laminate by laminating an anode; a porous substrate and a separator disposed on one side of the porous substrate; and a cathode; and the laminate having a capacity of 10 to 20 kgf / cm² 2 A method for manufacturing a lithium battery according to any one of claims 1, 2, 4 to 6, and 8, comprising the step of pressing under conditions of 70 to 90°C and 1 to 5 minutes. Claim 10 delete

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