Method for manufacturing lithium secondary battery

Abstract

The present invention relates to a method for manufacturing a lithium secondary battery, the method comprising the steps of: preparing an electrode assembly that includes a cathode, an anode and a separator; accommodating the electrode assembly in a battery case; manufacturing a pre-lithium secondary battery by injecting a first non-aqueous electrolyte into the battery case; activating the pre-lithium secondary battery; and injecting a second non-aqueous electrolyte into the activated pre-lithium secondary battery, wherein the first non-aqueous electrolyte includes a first organic solvent including a linear carbonate-based solvent, and the second non-aqueous electrolyte includes a second organic solvent including an ester-based solvent.

Description

Method for manufacturing lithium secondary battery The present invention relates to a method for manufacturing a lithium secondary battery. Recently, as the application areas of lithium secondary batteries have rapidly expanded to include not only power supply for electronic devices such as electric, electronic, communication, and computers, but also power storage for large-area devices such as automobiles and power storage devices, the demand for high-capacity, high-output, and high-stability secondary batteries is increasing. The above lithium secondary battery is generally composed of a cathode including a cathode active material, an anode including a cathode active material, an electrolyte that serves as a medium for transferring lithium ions, and a separator. At this time, carbon-based active materials, silicon-based active materials, etc. can be used as the cathode active material. In addition, lithium transition metal oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium nickel-cobalt-manganese composite transition metal oxide can be used as the cathode active material. The above lithium secondary battery is manufactured by forming an electrode assembly by interposing a separator between the positive and negative electrodes, inserting or housing the electrode assembly in a battery case, injecting a non-aqueous electrolyte that serves as a lithium ion transfer medium, and then sealing the electrode assembly. At this time, an activation process (formation) may be performed on the manufactured lithium secondary battery to secure battery performance. The above activation process is a step for activating a lithium secondary battery through electrochemical charging after battery assembly, and during the electrochemical charging, lithium ions from the positive electrode move to and are inserted into the negative electrode. At this time, highly reactive lithium ions react with the electrolyte to generate compounds such as Li2CO3, Li2O, LiOH, and LiF, and these compounds form a solid electrolyte interface (SEI) layer on the electrode surface. Since the SEI layer closely affects the lifespan and capacity maintenance, the formation of the SEI layer is an important factor. One object of the present invention is to provide a method for manufacturing a lithium secondary battery having excellent long-term life performance and resistance reduction effect by improving the high-temperature durability of the battery while significantly reducing gas generation. [1] The present invention provides a method for manufacturing a lithium secondary battery, comprising: a step of preparing an electrode assembly including a positive electrode, a negative electrode, and a separator; a step of housing the electrode assembly in a battery case; a step of injecting a first non-aqueous electrolyte into the battery case to manufacture a pre-lithium secondary battery; a step of activating the pre-lithium secondary battery; and a step of injecting a second non-aqueous electrolyte into the activated pre-lithium secondary battery, wherein the first non-aqueous electrolyte includes a first organic solvent including a linear carbonate-based solvent, and the second non-aqueous electrolyte includes a second organic solvent including an ester-based solvent. [2] The present invention provides a method for manufacturing a lithium secondary battery, wherein, in the above [1], the linear carbonate solvent includes at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. [3] The present invention provides a method for manufacturing a lithium secondary battery, wherein in at least one of the above [1] to [2], the first organic solvent further includes a cyclic carbonate solvent. [4] The present invention provides a method for manufacturing a lithium secondary battery, wherein in one or more of the above [1] to [3], the cyclic carbonate solvent includes at least one of ethylene carbonate and fluoroethylene carbonate. [5] The present invention provides a method for manufacturing a lithium secondary battery, wherein in at least one of the above [1] to [4], the first organic solvent comprises the linear carbonate solvent and the cyclic carbonate solvent in a volume ratio of 60:40 to 95:5. [6] The present invention provides a method for manufacturing a lithium secondary battery, wherein in at least one of the above [1] to [5], the first organic solvent does not include an ester solvent. [7] The present invention provides a method for manufacturing a lithium secondary battery, wherein in one or more of the above [1] to [6], the ester solvent includes at least one selected from the group consisting of ethyl propionate, propyl propionate, and 2,2-difluoroethyl acetate. [8] The present invention provides a method for manufacturing a lithium secondary battery, wherein in one or more of the above [1] to [7], the second organic solvent further includes at least one cyclic carbonate-based solvent selected from ethylene carbonate and fluoroethylene carbonate. [9] The present invention provides a method for manufacturing a lithium secondary battery, wherein in at least one of the above [1] to [8], the second organic solvent comprises the ester solvent and the cyclic carbonate solvent in a volume ratio of 60:40 to 95:5.

[0010] The present invention provides a method for manufacturing a lithium secondary battery, wherein in one or more of the above [1] to [9], the volume ratio of the injection amount of the first non-aqueous electrolyte and the injection amount of the second non-aqueous electrolyte is 50:50 to 99:1.

[0011] The present invention provides a method for manufacturing a lithium secondary battery, wherein at least one of the first non-aqueous electrolyte and the second non-aqueous electrolyte further comprises a lithium salt, in one or more of the above [1] to

[0010] .

[0012] The present invention provides a method for manufacturing a lithium secondary battery, wherein the step of activating the pre-lithium secondary battery comprises an electrochemical charging process of the pre-lithium secondary battery in at least one of the above [1] to

[0011] . The lithium secondary battery of the present invention comprises an injection process of two types of non-aqueous electrolytes, wherein the first non-aqueous electrolyte injected before activation comprises a linear carbonate-based solvent, and the second non-aqueous electrolyte injected after activation comprises an ester-based solvent. The first non-aqueous electrolyte comprises a carbonate-based solvent, and can form a durable and stable SEI layer on an electrode upon activation. The second non-aqueous electrolyte has less concern about gas generation due to electrolyte side reactions during battery operation. Due to the characteristics of the first non-aqueous electrolyte and the second non-aqueous electrolyte, and the timing of their injection, the lithium secondary battery manufactured from the present invention can have excellent long-term life performance and resistance reduction effect. The terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as having meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best manner. It should be understood that the terms “comprise,” “include,” or “have,” as used herein, are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. Hereinafter, the present invention will be described in more detail. Method for manufacturing lithium secondary battery The present invention relates to a method for manufacturing a lithium secondary battery. A method for manufacturing a lithium secondary battery according to the present invention comprises the steps of: preparing an electrode assembly including a positive electrode, a negative electrode, and a separator; storing the electrode assembly in a battery case; injecting a first non-aqueous electrolyte into the battery case to manufacture a pre-lithium secondary battery; activating the pre-lithium secondary battery; and injecting a second non-aqueous electrolyte into the activated pre-lithium secondary battery. The first non-aqueous electrolyte comprises a first organic solvent including a linear carbonate-based solvent, and the second non-aqueous electrolyte comprises a second organic solvent including an ester-based solvent. The lithium secondary battery of the present invention comprises an injection process of two types of non-aqueous electrolytes, wherein the first non-aqueous electrolyte injected before activation comprises a linear carbonate-based solvent, and the second non-aqueous electrolyte injected after activation comprises an ester-based solvent. The first non-aqueous electrolyte comprises a carbonate-based solvent, and can form a durable and stable SEI layer on an electrode upon activation. The second non-aqueous electrolyte has less concern about gas generation due to electrolyte side reactions during battery operation. Due to the characteristics of the first non-aqueous electrolyte and the second non-aqueous electrolyte, and the timing of their injection, the lithium secondary battery manufactured from the present invention can have excellent long-term life performance and resistance reduction effect. (1) Preparation of electrode assembly First, an electrode assembly including an anode, a cathode, and a separator is prepared. Specifically, the electrode assembly can be manufactured by interposing a separator between an anode and a cathode facing the anode. More specifically, the electrode assembly can be manufactured by sequentially stacking one or more basic units of an anode, a separator, and a cathode, specifically two or more. The above positive electrode may include a positive electrode active material. The above cathode active material is a compound capable of reversible intercalation and deintercalation, and is not particularly limited as long as it is a cathode active material used in the relevant field. Specifically, the above cathode active material is a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; lithium iron oxide such as LiFe3O4; lithium iron phosphate such as LiFePO4; and a chemical formula Li 1+c1 Mn 2-c1 Lithium manganese oxides such as O4(0≤c1≤0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; chemical formula LiNi 1-c2 M c2 Ni-site type lithium nickel oxide represented by O2 (wherein, M is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, and satisfies 0.01≤c2≤0.3); chemical formula LiMn 2-c3 M c3 O2 (wherein, M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, and satisfies 0.01≤c3≤0.1) or Li2Mn3MO8 (wherein, M is at least one selected from the group consisting of Fe, Co, Ni, Cu, and Zn); but the present invention is not limited thereto. The positive electrode may be a Li-metal positive electrode. More specifically, the cathode active material may include at least one selected from the group consisting of lithium cobalt oxide (LiCoO2), high nickel content lithium nickel cobalt manganese oxide, lithium manganese-rich oxide, and lithium iron phosphate. The above high nickel-containing lithium nickel cobalt manganese oxide can be represented by the following chemical formula A. [Chemical Formula A] Li1+x (Ni a Co b Mn c M d )O2 In the chemical formula A, M is at least one selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, and 1+x, a, b, c and d are atomic fractions of independent elements, respectively, 0≤x≤0.2, 0.50≤a<1, 0 <b≤0.25, 0<c≤0.25, 0≤d≤0.1, a+b+c+d=1이다. 바람직하게는, 상기 a, b, c 및 d는 각각 0.70≤a≤0.95, 0.025≤b≤0.20, 0.025≤c≤0.20, 0≤d≤0.05일 수 있다. 또한, 상기 a, b, c 및 d는 각각 0.80≤a≤0.95, 0.025≤b≤0.15, 0.025≤c≤0.15, 0≤d≤0.05일 수 있다. 또한, 상기 a, b, c 및 d는 각각 0.85≤a≤0.90, 0.05≤b≤0.10, 0.05≤c≤0.10, 0≤d≤0.03일 수 있다. The above lithium manganese-rich oxide may include a compound represented by the following chemical formula B. [Chemical Formula B] Li 1+s [Ni t Co u Mn v M 1 w ]O 2+z In the above chemical formula B, M 1is at least one selected from W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B and Mo, and 0.05≤s≤1, 0≤t≤0.5, 0≤u≤0.3, 0.5≤v<1.0, 0≤w≤0.2, 0≤z≤1. Preferably, in the chemical formula B, 0.05≤s≤1.0, 0.1≤t≤0.5, 0≤u≤0.1, 0.5≤v<1.0, 0≤w≤0.2, 0≤z≤1. More preferably, in the chemical formula B, 0.10≤s≤0.50, 0.1≤t≤0.5, 0≤u≤0.1, 0.6≤v<1.0, 0≤w≤0.1, 0≤z≤0.50 may be satisfied. The above lithium iron phosphate may include a compound represented by the following chemical formula C. [Chemical formula C] Li 1+e Fe 1-g M 2 g (PO 4-f )X f In the above chemical formula C, M 2 is one or more elements selected from Co, Ni, Mn, Al, Mg, Ti, and V, and X is F, S, or N, and 0≤g≤0.5; -0.5≤e≤+0.5; 0≤f≤0.1. The chemical formula C can be specifically represented as LiFePO4 (g=0, e=0, and f=0). The above positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector. The positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Specifically, the positive electrode current collector may include at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and an aluminum-cadmium alloy, preferably aluminum. The thickness of the above positive electrode collector can typically have a thickness of 3 to 500 μm. The above-mentioned positive electrode current collector may form fine irregularities on the surface to strengthen the bonding strength of the positive electrode active material. For example, the above-mentioned positive electrode current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc. The positive electrode active material layer may be disposed on at least one surface of the positive electrode current collector. Specifically, the positive electrode active material layer may be disposed on one surface or both surfaces of the positive electrode current collector. The above-mentioned positive electrode active material layer may include the above-mentioned positive electrode active material. The above-described positive electrode active material layer may optionally further include a binder and / or a conductive material together with the above-described positive electrode active material. The above binder is a component that assists in the binding of the active material and the conductive material and the binding to the current collector, and specifically, may include at least one selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, and fluororubber, preferably polyvinylidene fluoride. The above binder may be included in the positive electrode active material layer at 1 to 20 wt%, preferably 1.2 to 10 wt%, in order to sufficiently secure binding force between components such as the positive electrode active material. The conductive material may be used to assist and improve conductivity in a secondary battery, and is not particularly limited as long as it has conductivity without causing a chemical change. Specifically, the positive electrode conductive material may include at least one selected from the group consisting of graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, paneth black, lamp black, thermal black, etc.; conductive fibers such as carbon fibers or metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives, and preferably, the positive electrode conductive material may include carbon nanotubes in terms of improving conductivity. The above-mentioned conductive material may be included in the positive electrode active material layer at 1 wt% to 20 wt%, preferably 1.2 wt% to 10 wt%, in order to sufficiently secure electrical conductivity. The thickness of the above positive electrode active material layer may be 5 µm to 500 µm, preferably 20 µm to 200 µm. The above positive electrode can be manufactured by coating a positive electrode slurry including a positive electrode active material and optionally a binder, a conductive material, and a solvent for forming a positive electrode slurry on the positive electrode current collector, and then drying and rolling. The above cathode can be opposed to the above anode. The above negative electrode may include a negative electrode active material. The above negative active material is a material capable of reversibly inserting / deleting lithium ions, and may include at least one selected from the group consisting of a carbon-based active material, a (semi)metal-based active material, and lithium metal, and specifically may include at least one selected from a carbon-based active material and a (semi)metal-based active material. The above carbon-based active material may include at least one selected from the group consisting of artificial graphite, natural graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon, and preferably may include at least one selected from the group consisting of artificial graphite and natural graphite. The average particle diameter (D) of the above carbon-based active material 50 ) may be 10 ㎛ to 30 ㎛, preferably 15 ㎛ to 25 ㎛, in order to ensure structural stability during charging and discharging and reduce side reactions with the electrolyte. Specifically, the (semi)metal-based active material may include at least one (semi)metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; an alloy of lithium and at least one (semi)metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; an oxide of at least one (semi)metal selected from the group consisting of Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, V, Ti, and Sn; lithium titanium oxide (LTO); lithium vanadium oxide; etc. More specifically, the (semi)metal-based active material may include a silicon-based active material. The above silicon-based active material is SiO x It may include a compound represented by (0≤x<2). In the case of SiO2, since it does not react with lithium ions and thus cannot store lithium, it is preferable that x is within the above range, and more preferably, the silicon-based active material may be SiO. The average particle diameter (D) of the above silicon-based active material 50) may be 1 ㎛ to 30 ㎛, preferably 2 ㎛ to 15 ㎛, in order to reduce side reactions with the electrolyte while ensuring structural stability during charging and discharging. The above negative electrode may include a negative electrode current collector; and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector. In this case, the negative electrode active material may be included in the negative electrode active material layer. The above negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. Specifically, the negative electrode current collector may be made of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., an aluminum-cadmium alloy, etc. The above negative electrode collector may typically have a thickness of 3 to 500 μm. The above negative electrode current collector may form fine irregularities on the surface to strengthen the bonding strength of the negative electrode active material. For example, the above negative electrode current collector may be used in various forms such as a film, a sheet, a foil, a net, a porous body, a foam, a non-woven fabric, etc. The above negative electrode active material layer may be disposed on at least one surface of the negative electrode current collector, specifically, one surface or both surfaces of the negative electrode current collector. The above negative active material may be included in the negative active material layer in an amount of 60 to 99 wt%, preferably 75 to 95 wt%. Description of other positive electrode active materials is omitted as it has been described above. The above negative electrode active material layer may further include a binder and / or a conductive material together with the negative electrode active material. The above binder is used to improve the performance of the battery by improving the adhesion between the negative electrode active material layer and the negative electrode current collector, and may include, for example, at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethylmethacrylate, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluororubber, and materials in which hydrogens of these are substituted with Li, Na or Ca, etc., and also may include various copolymers thereof. may include: The above binder may be included in the negative electrode active material layer in an amount of 0.5 wt% to 10 wt%, preferably 1 wt% to 5 wt%. The conductive material is not particularly limited as long as it is conductive and does not cause a chemical change in the battery, and for example, graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, paneth black, lamp black, thermal black, etc.; conductive fibers such as carbon fibers or metal fibers; conductive tubes such as carbon nanotubes; fluorocarbon; metal powder such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives, etc. can be used. The above-mentioned conductive agent may be included in the negative electrode active material layer in an amount of 0.5 wt% to 10 wt%, preferably 1 wt% to 5 wt%. The thickness of the above negative active material layer may be 10 µm to 200 µm, preferably 20 µm to 150 µm. The above negative electrode can be manufactured by coating a negative electrode slurry including a negative electrode active material, a binder, a conductive material and / or a solvent for forming a negative electrode slurry on at least one surface of a negative electrode current collector, and then drying and rolling. The solvent for forming the negative electrode slurry may include at least one selected from the group consisting of distilled water, NMP (N-methyl-2-pyrrolidone), ethanol, methanol, and isopropyl alcohol, preferably distilled water, in order to facilitate dispersion of the negative electrode active material, binder, and / or conductive agent, for example. The solid content of the negative electrode slurry may be 30 wt% to 80 wt%, specifically 40 wt% to 70 wt%. The above separator may be interposed between the anode and the cathode. In addition, as the separator, a conventional porous polymer film that has been conventionally used as a separator, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, may be used alone or in a laminated manner, or a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc., may be used, but is not limited thereto. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength may be used, and may optionally be used in a single-layer or multi-layer structure. (2) Storage of electrode assembly Next, the electrode assembly is housed in a battery case. The battery case can play a role of protecting internal components of a lithium secondary battery, such as the electrode assembly, the first non-aqueous electrolyte described below, and the second non-aqueous electrolyte. The battery case described above may be any battery case known in the art without limitation. Specifically, the battery case may be a can-type battery case or a pouch-type battery case depending on the exterior or application form of the electrode assembly. Specifically, the battery case may be a pouch-type battery case. When the battery case is a pouch-type battery case, the pouch-type battery case can be manufactured by molding a pouch film laminate in which a substrate layer, a gas barrier layer, and a sealant layer are laminated. The substrate layer can include polyethylene terephthalate (PET), nylon, or the like. The gas barrier layer can include at least one selected from aluminum and stainless steel, and specifically can include aluminum. The sealant layer can be made of a polyolefin resin such as polypropylene (PP) and / or polyethylene (PE). By molding the pouch film laminate, an empty space in which the electrode assembly can be accommodated can be formed, and the electrode assembly can be accommodated in the empty space. (3) Injection of the first non-aqueous electrolyte Next, a first non-aqueous electrolyte is injected into the battery case. The first non-aqueous electrolyte comprises a first organic solvent. The first organic solvent comprises a linear carbonate solvent. The above first organic solvent includes a linear carbonate solvent, and is partially decomposed in the activation process described below to contribute to the formation of an SEI layer on the electrode. The SEI layer formed from the decomposition of the linear carbonate solvent has excellent durability and stability, and has the advantage of being advantageous in reducing resistance. If a solvent other than the linear carbonate solvent (for example, an ester solvent) is used, excessive decomposition may cause an increase in resistance and an increase in the durability of the SEI film. In this aspect, the first organic solvent may not include an ester solvent. The linear carbonate solvent may specifically include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethylmethyl carbonate (EMC), methylpropyl carbonate, and ethylpropyl carbonate, and more specifically may include at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate, and more specifically may include ethylmethyl carbonate. The above first organic solvent may further include a cyclic carbonate solvent together with the linear carbonate solvent. The cyclic carbonate solvent is a high-viscosity organic solvent having a high dielectric constant and thus can easily dissociate a lithium salt in the electrolyte. Specifically, the cyclic carbonate solvent may include at least one selected from the group consisting of ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate, and more specifically, may include at least one selected from the group consisting of ethylene carbonate (EC) and fluoroethylene carbonate (FEC), and even more specifically, may include ethylene carbonate (EC). When the first organic solvent includes the linear carbonate-based solvent and the cyclic carbonate-based solvent, the first organic solvent may include the linear carbonate-based solvent and the cyclic carbonate-based solvent in a volume ratio of 60:40 to 95:5, specifically, a volume ratio of 65:35 to 90:10, and more specifically, a volume ratio of 68:32 to 85:15. In this case, the first organic solvent is preferable in that it can simultaneously satisfy high dielectric constant and low viscosity characteristics and implement excellent ion conductivity characteristics, thereby enabling formation of a stable SEI layer upon activation by the first organic solvent. The above first non-aqueous electrolyte may further comprise a lithium salt (which may be represented as a first lithium salt). As the lithium salt, various lithium salts commonly used in non-aqueous electrolytes for lithium secondary batteries can be used without limitation. For example, the lithium salt may be Li as a cation. + , and the anion is F - , Cl - , Br - , I - , NO3- , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , B 10 Cl 10 - , BF2C2O4 - , BC4O8 - , PF4C2O4 - , PF2C4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , CH3SO3 - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - It may include at least one selected from the group consisting of: Specifically, the lithium salts are LiCl, LiBr, LiI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10, LiBOB (LiB(C2O4)2), LiCF3SO3, LiFSI (LiN(SO2F)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI (LiN(SO2CF2CF3)2). Specifically, the lithium salt may include at least one selected from the group consisting of LiBF4, LiClO4, LiPF6, LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiFSI (LiN(SO2F)2), and LiBETI (LiN(SO2CF2CF3)2). The above first non-aqueous electrolyte may further comprise an additive (which may be represented as a first additive). The above additive may be included in the first non-aqueous electrolyte for the purposes of preventing the non-aqueous electrolyte from decomposing and causing cathode collapse in a high-power environment, or for the purposes of improving low-temperature high-rate discharge characteristics, high-temperature stability, preventing overcharge, suppressing battery expansion at high temperatures, and strengthening the SEI layer. Specifically, the additive may be at least one selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, propane sultone, propene sultone, 1,4-butane sultone, ethane sultone, succinonitrile, adiponitrile, ethylene sulfate, lithium difluoro phosphate (LiDFP), lithium tetrafluoroborate (LiBF4), lithium difluoro(oxalato)borate (LiODFB), lithium bis-(oxalato)borate (LiBOB), and tris(trimethylsilyl) phosphate (TMSPi). Specifically, the additive may include at least one selected from the group consisting of vinylene carbonate, propane sultone and ethylene sulfate. More specifically, the additive may include vinylene carbonate, propane sultone and ethylene sulfate. The above additive may be included in the first non-aqueous electrolyte in an amount of 0.1 wt% to 15 wt%. The above first non-aqueous electrolyte may be injected into the battery case to manufacture a pre-lithium secondary battery. The pre-lithium secondary battery means that the electrode assembly and the first non-aqueous electrolyte are housed in the battery case, and is defined to distinguish it from a lithium secondary battery in which an activation process described below is performed and a second non-aqueous electrolyte is injected. After the first non-aqueous electrolyte is injected into the battery case, the battery case can be sealed. After the sealing, an activation process described below can be performed. (4) Activation of pre-lithium secondary batteries Next, the above-described pre-lithium secondary battery is activated. According to the present invention, since activation is performed after the first non-aqueous electrolyte is injected into the battery case, a durable and stable SEI layer can be formed on the electrode, specifically, the negative electrode. The step of activating the above-mentioned pre-lithium secondary battery can be applied without limitation to any activation process known in the art. Specifically, the step of activating the pre-lithium secondary battery may include an electrochemical charging process of the pre-lithium secondary battery. Alternatively, the step of activating the pre-lithium secondary battery may include an electrochemical charging process of the pre-lithium secondary battery and an electrochemical discharging process of the pre-lithium secondary battery. Alternatively, the step of activating the pre-lithium secondary battery may include a process of performing the process of electrochemically charging and discharging the pre-lithium secondary battery one or more cycles. Specifically, the step of activating the pre-lithium secondary battery can be performed by electrochemically charging at room temperature (20±5°C) at a C-rate of 0.05C to 2C, specifically 0.1C to 1C, to an SOC of 10% or more, specifically 20% or more, and more specifically 30% or more. Alternatively, the step of activating the pre-lithium secondary battery can be performed at a temperature of 45°C to 60°C and a pressure of 0.5 kgf / cm2 to 20 kgf / cm2, depending on the C-rate and SOC conditions. (5) Injection of the second non-aqueous electrolyte Next, a second non-aqueous electrolyte is injected into the activated pre-lithium secondary battery. The second non-aqueous electrolyte includes a second organic solvent. The second organic solvent includes an ester solvent. The ester solvent generates less gas such as CO2 when the battery is operated (charged and discharged) than other solvents such as linear carbonates, and is therefore very advantageous in terms of reducing resistance, improving long-term life performance, and enhancing safety. Meanwhile, if the ester solvent is injected before the initial activation process, there is a concern that an SEI layer with increased resistance may be formed due to a large degree of electrolyte side reaction. Therefore, the present invention injects the ester solvent after activation. The above ester solvent may include at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, butyl propionate, and 2,2-difluoroethyl acetate, and specifically, may include at least one selected from the group consisting of ethyl propionate, propyl propionate, and 2,2-difluoroethyl acetate, and more specifically, may include 2,2-difluoroethyl acetate in terms of simultaneously securing the effects of reducing resistance and improving durability of the SEI layer by forming an organic / inorganic composite SEI layer. The second organic solvent may further include a cyclic carbonate solvent together with the ester solvent. The cyclic carbonate solvent is a high-viscosity organic solvent having a high dielectric constant and thus can easily dissociate a lithium salt in the electrolyte. Specifically, the cyclic carbonate solvent may include at least one selected from the group consisting of ethylene carbonate (EC), fluoroethylene carbonate (FEC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate, and more specifically, may include at least one selected from the group consisting of ethylene carbonate (EC) and fluoroethylene carbonate (FEC), and even more specifically, may include ethylene carbonate (EC). When the second organic solvent includes the ester solvent and the cyclic carbonate solvent, the second organic solvent may include the ester solvent and the linear carbonate solvent in a volume ratio of 60:40 to 99:1, specifically, a volume ratio of 70:30 to 98:2, and more specifically, a volume ratio of 75:25 to 95:5. In this case, the second organic solvent is preferable in that it can simultaneously satisfy high dielectric constant and low viscosity characteristics and implement excellent ion conductivity characteristics, so that the gas generation reduction effect during battery operation using the second organic solvent can be exhibited at an excellent level. The second organic solvent may not include a linear carbonate solvent. Accordingly, it is preferable in that the generation of CO-2 can be reduced during charging / discharging or high-temperature storage of the battery. The second non-aqueous electrolyte may further comprise a lithium salt (which may be referred to as a second lithium salt). Specifically, at least one of the first non-aqueous electrolyte and the second non-aqueous electrolyte may further comprise a lithium salt. Alternatively, the second non-aqueous electrolyte may not comprise a lithium salt, and the first non-aqueous electrolyte may comprise a lithium salt. As the lithium salt, various lithium salts commonly used in non-aqueous electrolytes for lithium secondary batteries can be used without limitation. For example, the lithium salt may be Li as a cation. + , and the anion is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , ClO4 - , AlO4 - , AlCl4 - , PF6 - , SbF6 - , AsF6 - , B 10 Cl 10 - , BF2C2O4 - , BC4O8 - , PF4C2O4 - , PF2C4O8 - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , CF3SO3 - , C4F9SO3 - , CF3CF2SO3 - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , CH3SO3 - , CF3(CF2)7SO3 - , CF3CO2- , CH3CO2 - , SCN - and (CF3CF2SO2)2N - It may include at least one selected from the group consisting of: Specifically, the lithium salts are LiCl, LiBr, LiI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB (LiB(C2O4)2), LiCF3SO3, LiFSI (LiN(SO2F)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI (LiN(SO2CF2CF3)2). Specifically, the lithium salt may include at least one selected from the group consisting of LiBF4, LiClO4, LiPF6, LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiFSI (LiN(SO2F)2), and LiBETI (LiN(SO2CF2CF3)2). The second non-aqueous electrolyte may further comprise an additive (which may be denoted as a second additive). The above additive may be included in the first non-aqueous electrolyte for the purposes of preventing the non-aqueous electrolyte from decomposing and causing cathode collapse in a high-power environment, or for the purposes of improving low-temperature high-rate discharge characteristics, high-temperature stability, preventing overcharge, suppressing battery expansion at high temperatures, and strengthening the SEI layer. Specifically, the additive may be at least one selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate, propane sultone, propene sultone, 1,4-butane sultone, ethane sultone, succinonitrile, adiponitrile, ethylene sulfate, lithium difluoro phosphate (LiDFP), lithium tetrafluoroborate (LiBF4), lithium difluoro(oxalato)borate (LiODFB), lithium bis-(oxalato)borate (LiBOB), and tris(trimethylsilyl) phosphate (TMSPi). Specifically, the additive may include at least one selected from the group consisting of vinylene carbonate, propane sultone and ethylene sulfate. More specifically, the additive may include vinylene carbonate, propane sultone and ethylene sulfate. The above additive may be included in the second non-aqueous electrolyte in an amount of 0.1 wt% to 15 wt%. The second non-aqueous electrolyte may be injected into the battery case by partially opening the sealed portion of the activated pre-lithium secondary battery. After the injection of the second non-aqueous electrolyte, the battery case may be sealed. In the present invention, the volume ratio of the injection amount of the first non-aqueous electrolyte and the injection amount of the second non-aqueous electrolyte may be 50:50 to 95:5, specifically 60:40 to 92:8, more specifically 70:30 to 90:10, and more specifically 75:25 to 88:12. When it is within the above range, it is preferable in that the gas reduction effect during battery operation can be sufficiently exhibited, an electrode film having excellent durability can be formed during the initial activation process, and the electrode can be sufficiently impregnated with the electrolyte. The total volume of the injection amounts of the first non-aqueous electrolyte and the second non-aqueous electrolyte can be adjusted in consideration of the size of the electrode assembly, the battery case, etc., as is known in the art. Specifically, the total volume of the injection amounts of the first non-aqueous electrolyte and the second non-aqueous electrolyte can be designed so as to fill all of the empty space in the battery case in which the electrode assembly is accommodated. More specifically, at this time, the total volume of the first non-aqueous electrolyte and the second non-aqueous electrolyte can be designed so as to fill not only the empty space excluding the space in the battery case in which the electrode assembly is accommodated, but also the empty space formed by the pores of the electrodes and separators in the electrode assembly. For example, the injection weight of the first non-aqueous electrolyte and the second non-aqueous electrolyte per capacity of the secondary battery can be on the level of 2.0 g / Ah to 2.5 g / Ah, but is not limited thereto. The operating voltage of the lithium secondary battery manufactured from the manufacturing method of the present invention may be 4.35 V or higher, specifically 4.4 V or higher. The lithium secondary battery manufactured from the manufacturing method of the present invention is preferable because it can achieve improved life performance and high-temperature storage performance even at a high operating voltage due to the above-described characteristics. There is no particular limitation on the external shape of the lithium secondary battery of the present invention, but it may be in the shape of a cylinder, a square, a pouch, or a coin using a can. Hereinafter, the present invention will be described in more detail through specific examples. However, the following examples are merely examples to help understand the present invention and do not limit the scope of the present invention. It will be obvious to those skilled in the art that various changes and modifications are possible within the scope and technical idea of ​​the present description, and it is natural that such changes and modifications fall within the scope of the appended patent claims. Examples and Comparative Examples Example 1 (Manufacturing of electrode assembly, storage in battery case) Cathode active material (Li[Ni 0.6 Co 0.1 Mn 0.3 ]O2): Conductive agent (carbon nanotube): Binder (polyvinylidene fluoride) was added to N-methyl-2-pyrrolidone (NMP) as a solvent in a weight ratio of 97.0:1.2:1.8 to prepare a cathode slurry. The cathode slurry was applied to one surface of a 15 μm thick cathode current collector (Al thin film), dried, and roll pressed to form a cathode active material layer (thickness: 137 μm), which was used as a cathode. Negative electrode slurry (solid content 53 wt%) was prepared by adding negative electrode active material (artificial graphite): conductive material (carbon black): binder (styrene-butadiene rubber and carboxymethyl cellulose) to distilled water as a solvent in a weight ratio of 97.4:0.5:2.1. The negative electrode slurry was applied to one surface of a 15 ㎛ thick negative electrode current collector (Cu thin film), dried, and roll pressed to form a negative electrode active material layer (thickness: 176 ㎛), which was used as a negative electrode. An electrode assembly was manufactured by interposing a polyethylene porous film separator between the positive and negative electrodes manufactured above. The above-mentioned manufactured electrode assembly was housed in an aluminum pouch-type battery case. (Manufacture and injection of the first non-aqueous electrolyte) As the first organic solvent, a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) in a volume ratio of 30:70 was used. A first non-aqueous electrolyte was prepared by adding LiPF6 as a lithium salt and vinylene carbonate, propane sultone, and ethylene sulfate as first additives to the first organic solvent. The above LiPF6 was added to the first non-aqueous electrolyte at a concentration of 1 mol / L. The vinylene carbonate, propane sultone, and ethylene sulfate were each added to the first non-aqueous electrolyte at an amount of 0.5 wt%. A first non-aqueous electrolyte was injected into an aluminum pouch-shaped battery case containing the above electrode assembly, and sealed to manufacture a free-lithium secondary battery. (activate) At room temperature, the above-mentioned pre-lithium secondary battery was activated by charging it to 30% SOC in CC mode at 0.1C. (Injection of second non-aqueous electrolyte) As a second organic solvent, a mixture of ethylene carbonate (EC) and 2,2-difluoroethyl acetate in a volume ratio of 30:70 was used. A second non-aqueous electrolyte was prepared by adding LiPF6 as a lithium salt and vinylene carbonate, propane sultone, and ethylene sulfate as second additives to the second organic solvent. The above LiPF6 was added to the second non-aqueous electrolyte at a concentration of 1 mol / L. The vinylene carbonate, propane sultone, and ethylene sulfate were each added to the second non-aqueous electrolyte at an amount of 0.5 wt%. After partially opening the battery case of the above-mentioned activated pre-lithium secondary battery, a second non-aqueous electrolyte was injected, and the battery case was sealed again to manufacture a lithium secondary battery. In the above lithium secondary battery, the volume ratio of the injection amount of the first non-aqueous electrolyte and the injection amount of the second non-aqueous electrolyte was 85:15. The total volume of the injection amounts of the first non-aqueous electrolyte and the second non-aqueous electrolyte was designed so that it could be injected into the empty space within the battery case. Example 2 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the total volumes of the injection amounts of the first non-aqueous electrolyte and the injection amounts of the second non-aqueous electrolyte were the same, and the volume ratio of the injection amounts of the first non-aqueous electrolyte and the injection amounts of the second non-aqueous electrolyte was adjusted to 95:5. Example 3 A lithium secondary battery was manufactured in the same manner as in Example 1, except that the total volumes of the injection amounts of the first non-aqueous electrolyte and the injection amounts of the second non-aqueous electrolyte were the same, and the volume ratio of the injection amounts of the first non-aqueous electrolyte and the injection amounts of the second non-aqueous electrolyte was adjusted to 75:25. Example 4 A lithium secondary battery was manufactured in the same manner as in Example 1, except that a mixture of ethylene carbonate (EC) and propyl propionate (PP) in a volume ratio of 30:70 was used as the second organic solvent. Comparative Example 1 (Manufacturing of electrode assembly, storage in battery case) The electrode assembly was housed in a battery case in the same manner as in Example 1. (Manufacture and injection of non-aqueous electrolyte) A non-aqueous electrolyte identical to the first non-aqueous electrolyte of Example 1 was prepared. The non-aqueous electrolyte manufactured as described above was injected into an aluminum pouch-shaped battery case containing the electrode assembly, and sealed to manufacture a pre-lithium secondary battery. At this time, the injection amount of the non-aqueous electrolyte was set to the same volume as the total volume of the injection amounts of the first non-aqueous electrolyte and the second non-aqueous electrolyte of Example 1. (activate) A lithium secondary battery of Comparative Example 1 was manufactured by performing an activation process in the same manner as in Example 1. Unlike Example 1, a separate non-aqueous electrolyte injection process was not performed on the lithium secondary battery of Comparative Example 1 after the activation process. Comparative Example 2 (Manufacturing of electrode assembly, storage in battery case) The electrode assembly was housed in a battery case in the same manner as in Example 1. (Manufacture and injection of non-aqueous electrolyte) A non-aqueous electrolyte identical to the second non-aqueous electrolyte of Example 1 was prepared. The non-aqueous electrolyte manufactured as described above was injected into an aluminum pouch-shaped battery case containing the electrode assembly, and sealed to manufacture a pre-lithium secondary battery. At this time, the injection amount of the non-aqueous electrolyte was set to the same volume as the total volume of the injection amounts of the first non-aqueous electrolyte and the second non-aqueous electrolyte of Example 1. (activate) A lithium secondary battery of Comparative Example 2 was manufactured by performing an activation process in the same manner as in Example 1. Unlike Example 1, a separate non-aqueous electrolyte injection process was not performed on the lithium secondary battery of Comparative Example 2 after the activation process. Comparative Example 3 (Manufacturing of electrode assembly, storage in battery case) The electrode assembly was housed in a battery case in the same manner as in Example 1. (Manufacture and injection of the first non-aqueous electrolyte) A non-aqueous electrolyte identical to the second non-aqueous electrolyte of Example 1 was prepared and used as the first non-aqueous electrolyte of Comparative Example 3. The non-aqueous electrolyte manufactured as described above was injected into an aluminum pouch-shaped battery case containing the electrode assembly, and sealed to manufacture a free-lithium secondary battery. (activate) The activation process of the pre-lithium secondary battery was performed using the same method as in Example 1. (Injection of second non-aqueous electrolyte) A non-aqueous electrolyte identical to the first non-aqueous electrolyte of Example 1 was prepared and used as the second non-aqueous electrolyte of Comparative Example 3. After partially opening the battery case of the above-mentioned activated pre-lithium secondary battery, a second non-aqueous electrolyte was injected, and the battery case was sealed again to manufacture a lithium secondary battery. In the above lithium secondary battery, the volume ratio of the injection amount of the first non-aqueous electrolyte and the injection amount of the second non-aqueous electrolyte was 85:15. Experimental example Experimental Example 1: Evaluation of High Temperature Cycle Performance The lithium secondary batteries manufactured in Examples 1 to 4 and Comparative Examples 1 to 3 above were charged to 4.4 V, 0.05 C at 45°C under CC / CV, 0.33 C conditions using an electrochemical charger / discharger, and then discharged to 2.5 V under CC, 0.33 C conditions, which was considered one cycle, to perform 200 charge / discharge cycles. The capacity retention rate is calculated using the formula below, and the results are shown in Table 1 below. Capacity retention rate (%) = {(discharge capacity after 200 cycles / discharge capacity after 1 cycle)} × 100 Experimental Example 2: Evaluation of High Temperature Storage Performance The lithium secondary batteries manufactured in Examples 1 to 4 and Comparative Examples 1 to 5 above were charged to 4.4 V, 0.05 C under CC / CV, 0.33 C conditions at 25°C and discharged to 2.5 V under CC, 0.33 C conditions to perform initial charge / discharge, and then charged to 4.4 V, 0.05 C under CC / CV, 0.33 C conditions at 25°C and stored at 60°C for 16 weeks. The volume increase rate was calculated using the formula below, and the results are shown in Table 1 below. Volume increase rate (%) = (volume of lithium secondary battery after 16 weeks of storage - initial volume) / (initial volume) × 100 Experimental Example 1 Experimental Example 2 Capacity retention rate (%) Volume increase rate (%) Example 193.4 3.7 Example 293.8 4.5 Example 393.13.5 Example 492.9 2.8 Comparative Example 192.36.8 Comparative Example 289.6 4.9 Comparative Example 390.7 5.1 Referring to Table 1 above, it can be confirmed that the lithium secondary batteries of Examples 1 to 4 manufactured by injecting the first non-aqueous electrolyte including a linear carbonate-based solvent as the first organic solvent according to the present invention and the second non-aqueous electrolyte including an ester-based solvent as the second organic solvent before and after the activation process, respectively, exhibit improved high-temperature life performance and volume reduction effect at the same time compared to the comparative examples that did not do so.

Claims

1. A step of preparing an electrode assembly including a positive electrode, a negative electrode, and a separator; A step of housing the above electrode assembly in a battery case; A step of manufacturing a pre-lithium secondary battery by injecting a first non-aqueous electrolyte into the battery case; A step of activating the above pre-lithium secondary battery; and A step of injecting a second non-aqueous electrolyte into the activated pre-lithium secondary battery; The first non-aqueous electrolyte comprises a first organic solvent comprising a linear carbonate solvent, A method for manufacturing a lithium secondary battery, wherein the second non-aqueous electrolyte comprises a second organic solvent including an ester solvent.

2. In claim 1, A method for manufacturing a lithium secondary battery, wherein the linear carbonate solvent comprises at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

3. In claim 1, A method for manufacturing a lithium secondary battery, wherein the first organic solvent further comprises a cyclic carbonate solvent.

4. In claim 3, A method for manufacturing a lithium secondary battery, wherein the above cyclic carbonate solvent comprises at least one of ethylene carbonate and fluoroethylene carbonate.

5. In claim 3, A method for manufacturing a lithium secondary battery, wherein the first organic solvent comprises the linear carbonate solvent and the cyclic carbonate solvent in a volume ratio of 60:40 to 95:

5.

6. In claim 1, A method for manufacturing a lithium secondary battery, wherein the first organic solvent does not include an ester solvent.

7. In claim 1, A method for manufacturing a lithium secondary battery, wherein the ester solvent comprises at least one selected from the group consisting of ethyl propionate, propyl propionate, and 2,2-difluoroethyl acetate.

8. In claim 1, A method for manufacturing a lithium secondary battery, wherein the second organic solvent further includes at least one cyclic carbonate solvent selected from ethylene carbonate and fluoroethylene carbonate.

9. In claim 8, A method for manufacturing a lithium secondary battery, wherein the second organic solvent comprises the ester solvent and the cyclic carbonate solvent in a volume ratio of 60:40 to 95:

5.

10. In claim 1, A method for manufacturing a lithium secondary battery, wherein the volume ratio of the injection amount of the first non-aqueous electrolyte and the injection amount of the second non-aqueous electrolyte is 50:50 to 99:

1.

11. In claim 1, A method for manufacturing a lithium secondary battery, wherein at least one of the first non-aqueous electrolyte and the second non-aqueous electrolyte further comprises a lithium salt.

12. In claim 1, A method for manufacturing a lithium secondary battery, wherein the step of activating the above-mentioned pre-lithium secondary battery includes an electrochemical charging process of the above-mentioned pre-lithium secondary battery.