Lithium secondary battery

Abstract

The present invention provides a lithium secondary battery comprising: a positive electrode; a negative electrode; a separator; and a non-aqueous electrolyte, wherein the positive electrode includes a positive electrode active material, the positive electrode active material includes lithium iron phosphate particles, the positive electrode has a loading amount of 450 mg / 25 cm2 to 740 mg / 25 cm2, the non-aqueous electrolyte includes a lithium salt, an organic solvent, and an additive, the additive includes at least one selected from the group consisting of compounds represented by chemical formulae 1 to 3 below, and the additive is included in the non-aqueous electrolyte in an amount of 0.1-3 wt%.

Description

Lithium secondary battery The present invention relates to a lithium secondary battery. As personal IT devices and computer networks have developed due to the development of the information society, and as a result, the overall dependence of society on electric energy has increased, there is a demand for technology development to efficiently store and utilize electric energy. Among the developed technologies, secondary batteries are the most suitable for various applications, and among these secondary batteries, lithium secondary batteries are attracting attention as they can be miniaturized to the point where they can be applied to personal IT devices and have the highest energy density. The present invention provides a lithium secondary battery having excellent low-temperature output performance by improving the impregnation property of the positive electrode into a non-aqueous electrolyte, wherein the positive electrode comprises lithium iron phosphate particles as a positive electrode active material and has a specific loading amount or more. [1] The present invention comprises a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte, wherein the positive electrode comprises a positive electrode active material, wherein the positive electrode active material comprises lithium iron phosphate particles, and the loading amount of the positive electrode is about 450 mg / 25 cm 2 740mg / 25cm 2 and the non-aqueous electrolyte comprises a lithium salt, an organic solvent and an additive, the additive comprises at least one selected from the group consisting of compounds represented by the following chemical formulas 1 to 3, and the additive is contained in the non-aqueous electrolyte in an amount of about 0.1 wt% to 3 wt%, thereby providing a lithium secondary battery. [Chemical Formula 1] In the above chemical formula 1, R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and n is an integer from 1 to 10. [Chemical formula 2] In the above chemical formula 2, m is an integer from 0 to 18. [Chemical Formula 3] In the above chemical formula 3, R2 and R3 are each independently an alkylene group having 1 to 10 carbon atoms, and R4 is an alkyl group having 1 to 20 carbon atoms substituted with one or more fluorines. [2] The present invention provides a lithium secondary battery according to the above [1], wherein in the chemical formula 1, n is an integer from 3 to 8. [3] The present invention provides a lithium secondary battery, wherein in the chemical formula 1, R1 is hydrogen, in at least one of the above [1] to [2]. [4] The present invention provides a lithium secondary battery, wherein in one or more of the above [1] to [3], the compound represented by the chemical formula 1 includes at least one selected from the group consisting of compounds represented by the following chemical formulas 1-1 to 1-3. [Chemical Formula 1-1] [Chemical Formula 1-2] [Chemical Formula 1-3] . [5] The present invention provides a lithium secondary battery, wherein in the chemical formula 2, m is an integer from 2 to 8, in at least one of the above [1] to [4]. [6] The present invention provides a lithium secondary battery, wherein in one or more of the above [1] to [5], the compound represented by the chemical formula 2 includes at least one selected from the group consisting of compounds represented by the following chemical formulas 2-1 to 2-4. [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 2-3] [Chemical Formula 2-4] . [7] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to [6], in the chemical formula 3, R2 and R3 are each independently an alkylene group having 1 to 5 carbon atoms, and R4 is an alkyl group having 3 to 20 carbon atoms substituted with one or more fluorines. [8] The present invention provides a lithium secondary battery, wherein in one or more of the above [1] to [7], in the chemical formula 3, R4 is an alkyl group having 4 to 8 carbon atoms substituted with one or more fluorines. [9] The present invention provides a lithium secondary battery comprising a compound represented by the chemical formula 3 in at least one of the above [1] to [8], wherein the compound represented by the chemical formula 3 is a compound represented by the following chemical formula 3-1. [Chemical Formula 3-1] .

[0010] The present invention relates to a method for producing a composition according to one or more of the above [1] to [9], wherein the loading amount of the anode is about 500 mg / 25 cm 2 600mg / 25cm 2 It provides a lithium secondary battery.

[0011] The present invention provides a lithium secondary battery according to at least one of the above [1] to

[0010] , wherein the non-aqueous electrolyte further includes vinylene carbonate.

[0012] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to

[0011] , the organic solvent includes a cyclic carbonate solvent and a linear carbonate solvent.

[0013] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to

[0012] , the linear carbonate includes dimethyl carbonate.

[0014] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to

[0013] , the lithium iron phosphate particles include a compound represented by the following chemical formula A. [Chemical Formula A] Li 1+a Fe 1-s M s (PO 4-b )X b In the chemical formula A, M is one or more elements selected from Co, Ni, Mn, Al, Mg, Ti, and V, X is F, S, or N, and 0≤s≤0.5; -0.5≤a≤+0.5; 0≤b≤0.1.

[0015] The present invention provides a lithium secondary battery comprising LiFePO4 in at least one of the above [1] to

[0014] . The lithium secondary battery according to the present invention is characterized by including a positive electrode having a specific loading amount or more and including lithium iron phosphate particles as a positive electrode active material; and a non-aqueous electrolyte including at least one compound represented by the chemical formulas 1 to 3 as an additive in a specific content. According to the lithium secondary battery of the present invention, the electrolyte impregnation property of a positive electrode having a high loading amount can be improved by using a non-aqueous electrolyte including the above-described additive in a specific content, so that the capacity development property of the lithium secondary battery can be excellent and the life performance and resistance characteristics can be improved. First, before describing the present invention, it should be noted that the terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, and should be interpreted as 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. Meanwhile, the terms used in this specification are only used to describe exemplary embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, it should be understood that the terms “comprise,” “include,” or “have,” etc., 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. In this specification, “%” means weight percent unless otherwise explicitly indicated. Before explaining the present invention, in the description of "carbon number a to b" in the specification, "a" and "b" mean the number of carbon atoms included in a specific functional group. That is, the functional group may include "a" to "b" carbon atoms. In addition, in this specification, unless otherwise defined, "substitution" means that at least one hydrogen bonded to carbon is replaced with an element other than hydrogen, for example, it means replacement with an alkyl group having 1 to 5 carbon atoms or a fluorine element. In this specification, the average particle diameter (D 50 ) can be defined as the particle size corresponding to 50% of the volume accumulation in the particle size distribution curve. The average particle size (D 50 ) can be measured, for example, using a laser diffraction method. The laser diffraction method can generally measure particle diameters from the submicron range to several mm, and can obtain results with high reproducibility and high resolution. As used herein, the terms “about,” “approximately,” and “substantially” are used to mean a range of or approximation to a numerical value or degree, taking into account inherent manufacturing and material tolerances. Typically, lithium secondary batteries are manufactured by injecting or impregnating a non-aqueous electrolyte into an electrode assembly consisting of a cathode, an anode, and a porous separator. Carbon-based active materials and silicon-based active materials are being considered as negative active materials for these lithium secondary batteries. Meanwhile, lithium-containing cobalt oxide, LiMnO2 with a layered crystal structure, LiMn2O4 with a spinel crystal structure, and lithium-containing nickel oxide (LiNiO2) are being considered as positive active materials. Recently, the use of lithium iron phosphate (e.g., LiFePO4)-based active materials, which have excellent thermal stability and are relatively inexpensive, is being considered as positive electrode active materials. However, in the case of the lithium iron phosphate-based active material, since it has a lower specific capacity than lithium cobalt oxide, lithium nickel oxide, etc., in order to increase the energy density of the positive electrode and lithium secondary battery including it, the lithium iron phosphate-based active material must be used at a high loading amount. However, the lithium iron phosphate-based active material with a high loading amount has problems in that it is difficult for the non-aqueous electrolyte to be sufficiently impregnated into the positive electrode, making it difficult to express the capacity, increasing the resistance, and reducing the lifespan. Considering these points, the present invention provides a lithium secondary battery having excellent low-temperature output performance by improving the impregnation property of the positive electrode into a non-aqueous electrolyte, wherein the positive electrode comprises lithium iron phosphate particles as a positive electrode active material and has a specific loading amount or more. Hereinafter, the present invention will be described in more detail. Lithium secondary battery The present invention relates to a lithium secondary battery. According to one embodiment, a lithium secondary battery according to the present invention comprises a cathode, an anode, a separator and a non-aqueous electrolyte, wherein the cathode comprises a cathode active material, wherein the cathode active material comprises lithium iron phosphate particles, and the loading of the cathode is about 450 mg / 25 cm 2 740mg / 25cm 2 , wherein the non-aqueous electrolyte comprises a lithium salt, an organic solvent and an additive, wherein the additive comprises at least one selected from the group consisting of compounds represented by the following chemical formulas 1 to 3, and the additive is contained in the non-aqueous electrolyte in an amount of about 0.1 wt% to 3 wt%. [Chemical Formula 1] In the above chemical formula 1, R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and n is an integer from 1 to 10. [Chemical formula 2] In the above chemical formula 2, m is an integer from 0 to 18. [Chemical Formula 3] In the above chemical formula 3, R2 and R3 are each independently an alkylene group having 1 to 10 carbon atoms, and R4 is an alkyl group having 1 to 20 carbon atoms substituted with one or more fluorines. The lithium secondary battery according to the present invention is characterized by including a positive electrode having a specific loading amount or more and including lithium iron phosphate particles as a positive electrode active material; and a non-aqueous electrolyte including at least one compound represented by the chemical formulas 1 to 3 as an additive in a specific content. According to the lithium secondary battery of the present invention, the electrolyte impregnation property of a positive electrode having a high loading amount can be improved by using a non-aqueous electrolyte including the above-described additive in a specific content, so that the capacity development property of the lithium secondary battery can be excellent and the life performance and resistance characteristics can be improved. The lithium secondary battery includes a positive electrode; a negative electrode; a separator; and a non-aqueous electrolyte. For example, the lithium secondary battery includes a positive electrode; a negative electrode opposite to the positive electrode; a separator interposed between the positive electrode and the negative electrode; and a non-aqueous electrolyte. According to one embodiment, the lithium secondary battery can be manufactured by a method including: a step of manufacturing 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 manufacturing a non-aqueous electrolyte including a lithium salt, an organic solvent, and an additive; and a step of injecting or impregnating the non-aqueous electrolyte into the battery case. (1) Bipolar The above positive electrode includes a positive electrode active material. The positive electrode active material includes lithium iron phosphate (e.g., LiFePO4) particles. The above lithium iron phosphate particles may include a compound represented by the following chemical formula A. [Chemical Formula A] Li 1+a Fe 1-s M s (PO 4-b )X b In the chemical formula A, M is one or more elements selected from Co, Ni, Mn, Al, Mg, Ti, and V, X is F, S, or N, and 0≤s≤0.5; -0.5≤a≤+0.5; 0≤b≤0.1. The above chemical formula A can be represented, for example, as LiFePO4 (a = 0, s = 0, and b = 0). The lithium iron phosphate particles may be in the form of primary particles or in the form of secondary particles in which two or more primary particles are aggregated. According to one embodiment, the lithium iron phosphate particles may be in the form of primary particles. The above lithium iron phosphate particles may be composed of primary particles, secondary particles formed by agglomeration of two or more primary particles, or a mixture of primary particles and secondary particles formed by agglomeration of two or more primary particles. When the above lithium iron phosphate particles are in the form of primary particles, the average particle diameter (D) of the above lithium iron phosphate particles 50 ) may be about 0.2 ㎛ to 3.0 ㎛, or 0.2 ㎛ to 2.0 ㎛, or 0.3 ㎛ to 1.5 ㎛. In addition, when the lithium iron phosphate particles are in the form of secondary particles in which two or more primary particles are aggregated, the primary particles have an average particle diameter (D 50 ) may be 0.2 ㎛ to 3.0 ㎛, or 0.2 ㎛ to 2.0 ㎛, or 0.3 ㎛ to 1.5 ㎛, and the secondary particles may have an average particle diameter (D 50 ) may be 7 ㎛ to 25 ㎛, or 10 ㎛ to 20 ㎛. According to one embodiment, the positive electrode active material may further include a carbon coating layer positioned on the surface of the lithium iron phosphate particles. The carbon coating layer may be introduced for the purpose of protecting the lithium iron phosphate particles, improving electrical conductivity, etc. The loading amount of the above anode is about 450 mg / 25 cm 2 740mg / 25cm 2 am. The above lithium iron phosphate particles have the advantages of excellent thermal stability and relatively low cost compared to other cathode active materials such as lithium cobalt oxide and lithium nickel-cobalt-manganese oxide, but their specific capacity is low, so the loading amount needs to be increased to implement high energy density. Increasing the loading amount of the cathode (for example, about 450 mg / 25 cm 2 740mg / 25cm 2), it is possible to implement a high energy density battery (e.g., a lithium secondary battery having a design capacity of at least 500 mAh and an initial discharge capacity of at least 500 mAh) when the non-aqueous electrolyte cannot be sufficiently impregnated into the cathode, so it is difficult to develop the capacity of the lithium secondary battery, the resistance increases, and the life performance tends to deteriorate. In consideration of these points, the lithium secondary battery according to the present invention is characterized by using a non-aqueous electrolyte in which at least one compound represented by the chemical formulas 1 to 3 is selected as an additive to the non-aqueous electrolyte and the content thereof is adjusted to a specific range. Through these characteristics, the electrolyte impregnation property of the positive electrode having a loading amount of about 450 mg / 25 cm2 to 740 mg / 25 cm2 can be improved, so that the capacity of the lithium secondary battery can be expressed at an excellent level and the life performance and resistance characteristics can be improved. For example, the lithium secondary battery according to the present invention is advantageous in terms of improving low-temperature output characteristics. In one embodiment, the loading amount of the anode is about 450 mg / 25 cm 2 740mg / 25cm 2 , 450mg / 25cm 2 730mg / 25cm 2 , 450mg / 25cm 2 720mg / 25cm 2 , 450mg / 25cm 2 710mg / 25cm 2 , or 450 mg / 25 cm 2 700mg / 25cm 2 , or about 500 mg / 25 cm 2 680mg / 25cm 2 , 500mg / 25cm 2 650mg / 25cm 2 , 500mg / 25cm 2 625mg / 25cm 2, or 500mg / 25cm 2 600mg / 25cm 2 It could be. 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. In this case, the positive electrode active material layer may include the above-described positive electrode active material. The above positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. For example, the positive 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 thickness of the above positive electrode collector may typically have a thickness of 3 ㎛ to 500 ㎛. 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 is disposed on at least one surface of the positive electrode current collector. According to one embodiment, 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 may be included in the positive electrode active material layer at about 80 wt% to 99 wt%, taking into account sufficient capacity of the positive electrode active material, etc. The above-described positive electrode active material layer may 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 may include, for example, 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, or polyvinylidene fluoride. The above binder may be included in the positive electrode active material layer at about 1 wt% to 20 wt%, or about 1.2 wt% to 10 wt%, in order to sufficiently secure binding force between components such as the positive electrode active material. The above conductive material can 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. For example, 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, KETJENBLACK®, 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 black in terms of improving conductivity. The above-mentioned conductive material may be included in the positive electrode active material layer at about 1 wt% to 20 wt%, or about 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 about 100 ㎛ to 300 ㎛, or 150 ㎛ to 250 ㎛. 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 solvent for forming the positive electrode slurry may include an organic solvent such as NMP (N-methyl-2-pyrrolidone). The solid content of the positive electrode slurry may be about 40 wt% to 90 wt%, or about 50 wt% to 80 wt% according to one embodiment. (2) Cathode The above cathode can be opposed to the above anode. The above negative electrode includes a negative electrode active material. 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. For example, the above 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 about 3 ㎛ to 500 ㎛. 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 negative electrode active material layer is disposed on at least one surface of the negative electrode current collector. According to one embodiment, the negative electrode active material layer may be disposed on one surface or both surfaces of the negative electrode current collector. The above negative active material layer may include a negative active material. The above negative active material is a material capable of reversibly inserting / de-inserting 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 according to one embodiment, 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 graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon, and preferably may include graphite. The graphite 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 about 10 ㎛ to 30 ㎛, or about 15 ㎛ to 25 ㎛, in order to ensure structural stability during charge and discharge and reduce side reactions with the electrolyte. For example, 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. In one embodiment, 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, x is set within the above range, and according to one embodiment, the silicon-based active material may be SiO. The average particle diameter (D) of the above silicon-based active material 50 ) may be about 1 ㎛ to 30 ㎛, or 2 ㎛ to 15 ㎛, in order to reduce side reactions with the electrolyte while ensuring structural stability during charge and discharge. The above negative active material may be included in the negative active material layer at about 60 wt% to 99 wt%, or about 75 wt% to 95 wt%. 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 at about 0.5 wt% to 10 wt%, or about 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, KETJENBLACK®, 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 material may be included in the negative electrode active material layer in an amount of about 0.5 wt% to 10 wt%, or about 1 wt% to 5 wt%. The thickness of the negative active material layer may be about 50 ㎛ to 300 ㎛, or about 100 ㎛ to 200 ㎛. The loading amount of the above negative active material layer is about 200 mg / 25 cm 2 500mg / 25cm 2 , or about 250 mg / 25 cm 2 400mg / 25cm 2 It could be. 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, for example, at least one selected from the group consisting of distilled water, NMP (N-methyl-2-pyrrolidone), ethanol, methanol, and isopropyl alcohol, or distilled water, in order to facilitate dispersion of the negative electrode active material, binder, and / or conductive agent. The solid content of the negative electrode slurry may be about 30 wt% to 80 wt%, or about 40 wt% to 70 wt% according to one embodiment. (3) Membrane The above separator may be interposed between the anode and the cathode. As the above-mentioned separator, a conventional porous polymer film used as a conventional 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, can 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., can 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 can be used, and can optionally be used in a single-layer or multi-layer structure. (4) Non-aqueous electrolyte 1) Lithium salt First, let me explain lithium salts as follows. In the non-aqueous electrolyte for a lithium secondary battery according to one embodiment of the present invention, the lithium salt may be any of those commonly used in electrolytes for lithium secondary batteries without limitation, and for example, 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 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , CH3SO3 - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - At least one selected from the group consisting of may be mentioned. For example, the lithium salt may be LiCl, LiBr, LiI, LiBF4, LiClO4, LiAlO4, LiAlCl4, LiPF6, LiSbF6, LiAsF6, LiB 10 Cl 10 , LiBOB (LiB(C2O4)2), LiCF3SO3, LiTFSI (LiN(SO2CF3)2), LiFSI (LiN(SO2F)2), LiCH3SO3, LiCF3CO2, LiCH3CO2, and LiBETI (LiN(SO2CF2CF3)2). The lithium salt may include a single substance or a mixture of two or more substances 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), or may include LiPF6. The above lithium salt may be appropriately changed within a normally usable range, but may be included in the electrolyte at a concentration of about 0.8 M to 3.0 M, or about 1.0 M to 3.0 M, in order to obtain the effect of forming a film for preventing corrosion on the electrode surface. At this time, the unit “M” may mean molar concentration, and specifically, “mol / L”. When the concentration of the lithium salt satisfies the above range, the viscosity of the non-aqueous electrolyte can be controlled to implement optimal impregnation properties, and the mobility of lithium ions can be improved, thereby obtaining the effect of improving the capacity characteristics and cycle characteristics of the lithium secondary battery. 2) Organic solvent The above organic solvent may be used without limitation as long as it is an organic solvent used as a non-aqueous electrolyte for a lithium secondary battery. For example, the organic solvent may include at least one selected from the group consisting of a cyclic carbonate solvent and a linear carbonate solvent. According to one embodiment, the organic solvent may include a cyclic carbonate solvent and a linear carbonate solvent. The organic solvent may include a cyclic carbonate solvent and a linear carbonate solvent. The above 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 (VC), and according to one embodiment, may include ethylene carbonate in that it is a high-viscosity organic solvent with a high dielectric constant and thus can easily dissociate a lithium salt in the electrolyte. For example, the cyclic carbonate solvent may 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 may include dimethyl carbonate as an organic solvent having low viscosity and low dielectric constant, particularly in terms of excellent electrolyte impregnation properties. When the linear carbonate solvent contains dimethyl carbonate, the linear carbonate solvent may further contain ethyl methyl carbonate together with the dimethyl carbonate. When the linear carbonate further contains ethyl methyl carbonate, the stability of the SEI (Solid Electrolyte Interphase) film can be further improved. The volume ratio of the cyclic carbonate solvent and the linear carbonate solvent may be about 10:90 to 50:50, or about 15:85 to 50:50, or about 20:80 to 35:65 according to one embodiment, and when it is in the above range, high ion transfer characteristics and low viscosity of the electrolyte can be achieved. In one embodiment, the organic solvent can include about 10 vol % to 50 vol % of the ethylene carbonate, about 5 vol % to 55 vol % of the dimethyl carbonate and about 20 vol % to 70 vol % of the ethylmethyl carbonate, or about 20 vol % to 40 vol % of the ethylene carbonate, about 7 vol % to 45 vol % of the dimethyl carbonate and about 25 vol % to 65 vol % of the ethylmethyl carbonate, or in one embodiment about 25 vol % to 35 vol % of the ethylene carbonate, about 7 vol % to 15 vol % of the dimethyl carbonate and about 50 vol % to 68 vol % of the ethylmethyl carbonate. When in the above range, the stability of the negative SEI film is improved while improving the electrolyte impregnation property. Meanwhile, the organic solvent may be used without limitation by adding organic solvents commonly used in non-aqueous electrolytes as needed. For example, at least one organic solvent among an ester solvent, an ether solvent, a glyme solvent, and a nitrile solvent may be additionally included. The above ester solvent may include at least one selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone. As the above ether solvent, any one selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, 1,3-dioxolane (DOL), and 2,2-bis(trifluoromethyl)-1,3-dioxolane (TFDOL) or a mixture of two or more thereof may be used, but is not limited thereto. The above-mentioned glyme solvent has a high dielectric constant and low surface tension compared to linear carbonate solvents, and is a solvent with low reactivity with metals, and may include at least one selected from the group consisting of dimethoxyethane (glyme, DME), diethoxyethane, diglyme, tri-glyme, and tetra-glyme (TEGDME), but is not limited thereto. The above nitrile solvent may be at least one selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile, but is not limited thereto. Meanwhile, the remainder of the non-aqueous electrolyte, excluding the lithium salt and additives, may be an organic solvent unless otherwise specified. (3) Additives The non-aqueous electrolyte of the present invention contains an additive. The above additive comprises at least one selected from the group consisting of compounds represented by the following chemical formulas 1 to 3. [Chemical Formula 1] In the above chemical formula 1, R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and n is an integer from 1 to 10. [Chemical formula 2] In the above chemical formula 2, m is an integer from 0 to 18. [Chemical Formula 3] In the above chemical formula 3, R2 and R3 are each independently an alkylene group having 1 to 10 carbon atoms, and R4 is an alkyl group having 1 to 20 carbon atoms substituted with one or more fluorines. For example, at least one compound represented by the chemical formulas 1 to 3 is present in the loading amount (450 to 740 mg / 25 cm 2 ) can significantly improve the electrolyte impregnation property of the cathode, prevent the problem of lithium precipitation at low temperatures, and thereby improve the output characteristics of the lithium secondary battery, especially the low-temperature output characteristics, and realize an excellent capacity expression rate. In addition, at least one of the compounds represented by the chemical formulas 1 to 3 includes a vinyl group or a propargyl group-containing functional group in its structure, thereby easily reductively decomposing on the surface of a negative electrode including a silicon-based active material, thereby forming an SEI film having low resistance and high passivation ability. In addition, at least one of the compounds represented by the chemical formulas 1 to 3 includes a fluorocarbon functional group in which one or more fluorine elements are substituted at a structural terminal, thereby forming a film having secured oxidation resistance on the surface of the positive electrode, thereby suppressing the elution of the transition metal from the positive electrode and suppressing the electrodeposition and precipitation of the eluted transition metal on the negative electrode, thereby preventing an internal short circuit. In the above chemical formula 1, R1 may be hydrogen or an alkyl group having 1 to 3 carbon atoms, or may be oxygen. In the above chemical formula 1, n may be an integer from 1 to 10, and in one embodiment, an integer from 3 to 8. If n is 0, it acts as a non-solvent, making it difficult to effectively form an electrode film containing an inorganic component such as LiF. If n is an integer greater than 10, miscibility with organic solvents, etc. may be reduced. The compound represented by the above chemical formula 1 may include at least one selected from the group consisting of compounds represented by the following chemical formulas 1-1 to 1-3, for example, and according to one embodiment, may include a compound represented by the following chemical formula 1-1. [Chemical Formula 1-1] [Chemical Formula 1-2] [Chemical Formula 1-3] In the above chemical formula 2, m may be an integer from 0 to 18, for example, an integer from 1 to 10, or an integer from 2 to 8 according to one embodiment. When the above m satisfies the above range, the thermal properties of the compound itself can be improved, and thus the stability of the film formed therefrom can be expected. In the above chemical formula 2, when m exceeds 18, since the fluorine element is contained in an excessive amount, the viscosity and non-polarity of the material increase, and thus the solubility in the electrolyte decreases, so the ionic conductivity decreases, which may result in poor battery performance. The compound represented by the above chemical formula 2 may include at least one selected from the group consisting of compounds represented by the following chemical formulas 2-1 to 2-4, and may include at least one selected from the group consisting of compounds represented by the following chemical formulas 2-1 to 2-2. [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 2-3] [Chemical Formula 2-4] In the above chemical formula 3, R2 and R3 are each independently an alkylene group having 1 to 5 carbon atoms, and R4 may be an alkyl group having 3 to 20 carbon atoms substituted with one or more fluorines. In addition, in the chemical formula 3, R2 and R3 are each independently an alkylene group having 1 to 3 carbon atoms, and R4 can be an alkyl group having 3 to 15 carbon atoms substituted with one or more fluorines. Alternatively, in the chemical formula 3, R4 may be an alkyl group having 4 to 8 carbon atoms substituted with one or more fluorines. Alternatively, according to one embodiment, the compound represented by the chemical formula 3 may include a compound represented by the following chemical formula 3-1. [Chemical Formula 3-1] At least one compound represented by the chemical formulas 1 to 3 is contained in the non-aqueous electrolyte in an amount of 0.1 to 3 wt%. According to one embodiment, at least one compound represented by Chemical Formulas 1 to 3 may be included in the non-aqueous electrolyte in an amount of about 0.1 wt % to 2.5 wt %, or about 0.2 wt % to 1 wt %. Meanwhile, the non-aqueous electrolyte may further include an additional additive. When the non-aqueous electrolyte further includes an additional additive, at least one compound among the compounds represented by the chemical formulas 1 to 3 described above may be expressed as a “first additive,” and the additional additive may be expressed as a “second additive.” The above additive may include other additional additives in addition to the compound represented by the chemical formula 1, as needed, in order to prevent the non-aqueous electrolyte from decomposing in a high-power environment and causing cathode collapse, or to further improve low-temperature high-rate discharge characteristics, high-temperature stability, overcharge prevention, and high-temperature battery expansion suppression effects. Examples of such additional additives include at least one selected from the group consisting of cyclic carbonate compounds, halogen-substituted carbonate compounds, sultone compounds, sulfate compounds, phosphate or phosphite compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, silane compounds, and lithium salt compounds. The above cyclic carbonate compound may be, for example, vinylene carbonate (VC) or vinylethylene carbonate. The above halogen-substituted carbonate compound may be, for example, fluoroethylene carbonate (FEC). The above sultone compound may be at least one compound selected from the group consisting of, for example, 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, 1,3-propene sultone (PRS), 1,4-butene sultone, and 1-methyl-1,3-propene sultone. The above sulfate compound may be, for example, ethylene sulfate (Esa), trimethylene sulfate (TMS), or methyl trimethylene sulfate (MTMS). The above phosphate or phosphite compound may be, for example, at least one compound selected from the group consisting of lithium difluoro(bisoxalato)phosphate, lithium difluorophosphate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite, tris(2,2,2-trifluoroethyl) phosphate, and tris(trifluoroethyl) phosphite. The above borate compounds may include tetraphenylborate, lithium difluoro(oxalato)borate (LiDFOB, LiB(C2O4)F2), or lithium bisoxalatoborate (LiB(C2O4)2, LiBOB). The above nitrile compound may be at least one compound selected from the group consisting of, for example, succinonitrile, adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile. The benzene compound may be, for example, fluorobenzene, etc., the amine compound may be, for example, triethanolamine or ethylenediamine, etc., and the silane compound may be, for example, tetravinylsilane. The above lithium salt compound is a compound different from the lithium salt included in the non-aqueous electrolyte, and may include lithium difluorophosphate (LiPO2F2) or LiBF4. When the above non-aqueous electrolyte contains vinylene carbonate, a more robust SEI film can be formed on the surface of the negative electrode during the initial activation process of the secondary battery. The above additional additive may be used by mixing two or more compounds, and the total content of the compound represented by the above chemical formula 1 and the additional additive may be included in an amount of about 50 wt% or less, or about 0.05 wt% to 20 wt%, or about 0.05 wt% to 10 wt%, based on the total weight of the non-aqueous electrolyte. When the total content of the additives satisfies the above range, the low-temperature output characteristics of the battery can be improved, the high-temperature storage characteristics and the high-temperature life characteristics can be more effectively improved, and the occurrence of side reactions of the battery due to the additives remaining after the reaction can be prevented. The lithium secondary battery according to the present invention as described above can be usefully used in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs). Accordingly, according to another embodiment of the present invention, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided. The above battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, including power tools; electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); or power storage systems. 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. The lithium secondary battery according to the present invention can be used not only as a battery cell used as a power source for a small device, but can also be preferably used as a unit battery in a medium- to large-sized battery module including a plurality of battery cells. Hereinafter, the present invention will be described through examples. At this time, the embodiments according to the present invention can be modified into various different forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to a person having average knowledge in the art. Examples and Comparative Examples 1. Anode loading: 600mg / 25cm 2 Example A-1 (Manufacturing of non-aqueous electrolyte) An organic solvent was prepared by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio of 30:60:10. LiPF6 as a lithium salt was dissolved in the above organic solvent to a molar concentration of 1.0 M. In addition, a non-aqueous electrolyte was prepared by adding vinylene carbonate (VC) and a compound represented by the chemical formula 1-1 to an organic solvent in which the lithium salt was dissolved. The vinylene carbonate was included in the non-aqueous electrolyte in an amount of 1 wt%. The compound represented by the chemical formula 1-1 was included in the non-aqueous electrolyte in an amount of 0.2 wt%. (Secondary battery manufacturing) Lithium iron phosphate (LiFePO4) particles having a carbon coating layer as a cathode active material, carbon black as a conductive material, and polyvinylidene fluoride (PVDF) as a binder were added to N-methyl-2-pyrrolidone (NMP) as a solvent at a weight ratio of 94:3:3 to prepare a cathode slurry. The cathode slurry was applied to a cathode current collector (Al thin film) having a thickness of 15 μm at a concentration of 600 mg / 25 cm. 2 After applying and drying with a loading amount of , a roll press was performed to manufacture a positive electrode. The average particle diameter (D) of the positive electrode active material 50 ) was 1.1㎛, and the lithium iron phosphate (LiFePO4) particles on which the carbon coating layer was formed were in the form of primary particles. An anode slurry was prepared by adding artificial graphite as an anode active material, SBR-CMC as a binder, and carbon black as a conductive material to water as a solvent at a weight ratio of 97:2:1. The anode slurry was applied to a copper (Cu) thin film as an anode current collector with a thickness of 15 ㎛ at a density of 300 mg / 25 cm. 2 After applying and drying with a loading amount of , a roll press was performed to manufacture a cathode. An electrode assembly was manufactured by sequentially laminating the above positive electrode, polyolefin-based porous separator, and negative electrode. The assembled electrode assembly was placed in a battery case, and the manufactured non-aqueous electrolyte was injected to manufacture a lithium secondary battery. Example A-2 A lithium secondary battery was manufactured in the same manner as in Example A-1, except that the compound represented by the chemical formula 1-1 was included in the non-aqueous electrolyte in an amount of 1 wt%. Example A-3 A lithium secondary battery was manufactured in the same manner as in Example A-1, except that the compound represented by the chemical formula 2-1 was included in the non-aqueous electrolyte in an amount of 0.2 wt% instead of the compound represented by the chemical formula 1-1. Example A-4 A lithium secondary battery was manufactured in the same manner as in Example A-3, except that the compound represented by the chemical formula 2-1 was included in the non-aqueous electrolyte in an amount of 1 wt%. Example A-5 A lithium secondary battery was manufactured in the same manner as in Example A-1, except that the compound represented by the chemical formula 3-1 was included in the non-aqueous electrolyte in an amount of 0.2 wt% instead of the compound represented by the chemical formula 1-1. Example A-6 A lithium secondary battery was manufactured in the same manner as in Example A-5, except that the compound represented by the chemical formula 3-1 was included in the non-aqueous electrolyte in an amount of 1 wt%. Comparative Example A-1 A lithium secondary battery was manufactured in the same manner as in Example A-1, except that the compound represented by the chemical formula 1-1 was not included in the non-aqueous electrolyte. Comparative Example A-2 A lithium secondary battery was manufactured in the same manner as in Example A-1, except that the compound represented by the chemical formula 1-1 was included in the non-aqueous electrolyte in an amount of 0.05 wt%. Comparative Example A-3 A lithium secondary battery was manufactured in the same manner as in Example A-1, except that the compound represented by the chemical formula 1-1 was included in the non-aqueous electrolyte at an amount of 5 wt%. Comparative Example A-4 A lithium secondary battery was manufactured in the same manner as in Example A-3, except that the compound represented by the chemical formula 2-1 was included in the non-aqueous electrolyte in an amount of 0.05 wt%. Comparative Example A-5 A lithium secondary battery was manufactured in the same manner as in Example A-3, except that the compound represented by the chemical formula 2-1 was included in the non-aqueous electrolyte at a content of 5 wt%. Comparative Example A-6 A lithium secondary battery was manufactured in the same manner as in Example A-5, except that the compound represented by the chemical formula 3-1 was included in the non-aqueous electrolyte in an amount of 0.05 wt%. Comparative Example A-7 A lithium secondary battery was manufactured in the same manner as in Example A-5, except that the compound represented by the chemical formula 3-1 was included in the non-aqueous electrolyte at a content of 5 wt%. Anode loading (mg / 25cm 2)Non-aqueous electrolyteOrganic solventLithium saltAdditiveAdditiveEC(vol%)EMC(vol%)DMC(vol%)LiPF6(mol / L)TypeContent(relative to non-aqueous electrolyte weight)VC(wt%)Example A-16003060101Chemical formula 1-10.21Example A-26003060101Chemical formula 1-111Example A-36003060101Chemical formula 2-10.21Example A-46003060101Chemical formula 2-111Example A-56003060101Chemical formula 3-10.21Example A-66003060101Chemical formula 3-111Comparative example A-16003060101--1Comparative example A-26003060101 Chemical Formula 1-10.051 Comparative Example A-36003060101 Chemical Formula 1-151 Comparative Example A-46003060101 Chemical Formula 2-10.051 Comparative Example A-56003060101 Chemical Formula 2-151 Comparative Example A-66003060101 Chemical Formula 3-10.051 Comparative Example A-76003060101 Chemical Formula 3-151 2. Anode loading: 500mg / 25cm 2 Example B-1 The loading amount of the anode is 600mg / 25cm 2 Not 500mg / 25cm 2 A lithium secondary battery was manufactured in the same manner as in Example A-1, except that the temperature was adjusted to . Example B-2 A lithium secondary battery was manufactured in the same manner as in Example B-1, except that the compound represented by the chemical formula 1-1 was included in the non-aqueous electrolyte in an amount of 1 wt%. Comparative Example B-1 A lithium secondary battery was manufactured in the same manner as in Example B-1, except that the compound represented by the chemical formula 1-1 was not included in the non-aqueous electrolyte. Comparative Example B-2 A lithium secondary battery was manufactured in the same manner as in Example B-1, except that the compound represented by the chemical formula 1-1 was included in the non-aqueous electrolyte in an amount of 0.05 wt%. Comparative Example B-3 A lithium secondary battery was manufactured in the same manner as in Example B-1, except that the compound represented by the chemical formula 1-1 was included in the non-aqueous electrolyte at a content of 5 wt%. Anode loading (mg / 25cm 2 )Non-aqueous electrolyteOrganic solventLithium saltAdditiveAdditiveEC(vol%)EMC(vol%)DMC(vol%)LiPF6(mol / L)TypeContent(relative to non-aqueous electrolyte weight)VC(wt%)Example B-15003060101Chemical formula 1-10.21Example B-25003060101Chemical formula 1-111Comparative example B-15003060101--1Comparative example B-25003060101Chemical formula 1-10.051Comparative example B-35003060101Chemical formula 1-151 3. Anode loading: 400mg / 25cm 2 Comparative Example C-1 The loading amount of the anode is 600mg / 25cm 2 Not 400mg / 25cm 2 A lithium secondary battery was manufactured in the same manner as in Example A-2, except that the temperature was adjusted to . Comparative Example C-2 A lithium secondary battery was manufactured in the same manner as in Comparative Example C-1, except that the compound represented by the chemical formula 1-1 was not included in the non-aqueous electrolyte. Anode loading (mg / 25cm 2 )Non-aqueous electrolyteOrganic solventLithium saltAdditiveAdditiveEC(vol%)EMC(vol%)DMC(vol%)LiPF6(mol / L)TypeContent(relative to non-aqueous electrolyte weight)VC(weight%)Comparative Example C-14003060101Chemical Formula 1-111Comparative Example C-24003060101--1 4. Anode loading: 750mg / 25cm 2 Comparative Example D-1 The loading amount of the anode is 600mg / 25cm 2 Not 750mg / 25cm 2A lithium secondary battery was manufactured in the same manner as in Example A-2, except that the temperature was adjusted to . Comparative Example D-2 A lithium secondary battery was manufactured in the same manner as in Comparative Example D-1, except that the compound represented by the chemical formula 1-1 was not included in the non-aqueous electrolyte. Anode loading (mg / 25cm 2 )Non-aqueous electrolyteOrganic solventLithium saltAdditiveAdditiveEC(vol%)EMC(vol%)DMC(vol%)LiPF6(mol / L)TypeContent(relative to non-aqueous electrolyte weight)VC(weight%)Comparative example D-17503060101Chemical formula 1-111Comparative example D-27503060101--1 Experimental example Experimental Example 1: Low Temperature Discharge Capacity Evaluation The low-temperature discharge capacity of the lithium secondary batteries manufactured according to the above-mentioned Examples A-1 to A-6, Comparative Examples A-1 to A-7; Examples B-1 to B-2, Comparative Examples B-1 to B-3; Comparative Examples C-1 to C-2; and Comparative Examples D-1 to D-2 was evaluated. The above lithium secondary batteries were charged to 3.65 V at -10°C and 0.2C, discharged to 2.5 V at 0.33C to perform initial charge / discharge, and the initial discharge capacity (unit: mAh) at this time was measured. Experimental Example 2: Evaluation of low temperature output characteristics The low-temperature output characteristics were evaluated for the lithium secondary batteries manufactured according to the above-mentioned Examples A-1 to A-6, Comparative Examples A-1 to A-7; Examples B-1 to B-2, Comparative Examples B-1 to B-3; Comparative Examples C-1 to C-2; and Comparative Examples D-1 to D-2. The above lithium secondary batteries were charged to 100% SOC (State of Charge) at 0.33C at 25℃ and the DC-IR (Direct current internal resistance) was calculated through the voltage drop that appeared when a discharge pulse was applied at 1.5C at -10℃. At this time, the time of applying the discharge pulse was 0.1 second or 10 seconds. Experimental results 1. Anode loading: 600mg / 25cm 2 Anode loading (mg / 25cm 2 )Experimental Example 1Experimental Example 2Initial Discharge Capacity (mAh, @-10℃)0.1s DC-IR (mOhm)10s DC-IR (mOhm)Example A-16001046240351Example A-26001058241348Example A-36001040242353Example A-46001051243351Example A-56001033245359Example A-66001042246356Comparative Example A-1600863254373Comparative Example A-2600876253371Comparative Example A-3600875257376Comparative Example A-4600874253372Comparative Example A-5600880258378Comparative Example A-6600871254373Comparative Example A-7600866260380 Referring to Table 5 above, lithium iron phosphate particles are included as the cathode active material, and the cathode loading is 450 to 740 mg / 25 cm 2 It can be confirmed that the lithium secondary batteries of Examples A-1 to A-6, which include a positive electrode; and a non-aqueous electrolyte containing at least one compound represented by Chemical Formulas 1 to 3 in an appropriate amount, exhibit superior capacity expression effect and superior low-temperature output performance compared to Comparative Examples A-1 to A-7. The lithium secondary batteries of Comparative Examples A-1 to A-7 not only exhibit lower capacities compared to Examples A-1 to A-6, but also exhibit poor low-temperature output characteristics. For example, Comparative Examples A-2 to A-7 have excessively low or excessive additive contents, and thus, compared to Comparative Example A-1, which does not contain any additives, the output characteristics show no improvement at all or rather a tendency to increase. Experimental results 2. Anode loading amount: 500mg / 25cm 2 Anode loading (mg / 25cm 2)Experimental Example 1Experimental Example 2Initial Discharge Capacity (mAh, @-10℃)0.1s DC-IR (mOhm)10s DC-IR (mOhm)Experimental Example B-1500868285414Experimental Example B-2500877287413Comparative Example B-1500720302434Comparative Example B-2500733299431Comparative Example B-3500710310441 Referring to Table 6 above, lithium iron phosphate particles are included as the cathode active material, and the cathode loading is 450 to 740 mg / 25 cm 2 It can be confirmed that the lithium secondary batteries of Examples B-1 to B-2, which include a positive electrode; and a non-aqueous electrolyte containing at least one compound represented by Chemical Formulas 1 to 3 in an appropriate amount, exhibit superior capacity expression effect and superior low-temperature output performance compared to Comparative Examples B-1 to B-3. Experimental results 3. Anode loading: 400mg / 25cm 2 Anode loading (mg / 25cm 2 )Experimental Example 1Experimental Example 2Initial Discharge Capacity (mAh, @-10℃)0.1s DC-IR (mOhm)10s DC-IR (mOhm)Comparative Example C-1400579375559Comparative Example C-2400580374559 Referring to Table 7 above, lithium iron phosphate particles are included as the cathode active material, and the cathode loading is 450 mg / 25 cm 2 In the case of the positive electrode below, it can be confirmed that there is no effect in capacity or output regardless of whether the compounds represented by the chemical formulas 1 to 3 are used as non-aqueous electrolyte additives. Experimental results 4. Anode loading: 750mg / 25cm 2 Anode loading (mg / 25cm 2 )Experimental Example 1Experimental Example 2Initial Discharge Capacity (mAh, @-10℃)0.1s DC-IR (mOhm)10s DC-IR (mOhm)Comparative Example D-17501056198303Comparative Example D-27501057198302 Referring to Table 8 above, lithium iron phosphate particles are included as the cathode active material, and the cathode loading is 740 mg / 25 cm 2 In the case of the excess anode, it can be confirmed that there is no effect in capacity or output, regardless of whether the compounds represented by the chemical formulas 1 to 3 are used as non-aqueous electrolyte additives. Although the present invention has been described above with reference to embodiments thereof, it will be understood by those skilled in the art or having ordinary knowledge in the art that various modifications and changes may be made to the present invention without departing from the spirit and technical scope of the present invention as set forth in the claims below. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the scope of the patent claims.

Claims

1. Containing a positive electrode, a negative electrode, a separator and a non-aqueous electrolyte; The above positive electrode contains a positive electrode active material, The above positive electrode active material comprises lithium iron phosphate particles, The loading amount of the above anode is 450mg / 25cm 2 740mg / 25cm 2 And, The above non-aqueous electrolyte comprises a lithium salt, an organic solvent and an additive, The above additive comprises at least one selected from the group consisting of compounds represented by the following chemical formulas 1 to 3: The above additive is included in the non-aqueous electrolyte at 0.1 wt% to 3 wt% in a lithium secondary battery: [Chemical Formula 1] In the above chemical formula 1, R1 is hydrogen or an alkyl group having 1 to 3 carbon atoms, and n is an integer of 1 to 10; [Chemical formula 2] In the above chemical formula 2, m is an integer from 0 to 18; [Chemical Formula 3] In the above chemical formula 3, R2 and R3 are each independently an alkylene group having 1 to 10 carbon atoms, and R4 is an alkyl group having 1 to 20 carbon atoms substituted with one or more fluorines.

2. In claim 1, A lithium secondary battery, wherein in the chemical formula 1 above, n is an integer from 3 to 8.

3. In claim 1, A lithium secondary battery, wherein in the chemical formula 1 above, R1 is hydrogen.

4. In claim 1, A lithium secondary battery comprising at least one compound represented by the chemical formula 1 and selected from the group consisting of compounds represented by the chemical formulas 1-1 to 1-3 below: [Chemical Formula 1-1] [Chemical Formula 1-2] [Chemical Formula 1-3] .

5. In claim 1, A lithium secondary battery, wherein in the chemical formula 2 above, m is an integer from 2 to 8.

6. In claim 1, A lithium secondary battery comprising at least one compound represented by the chemical formula 2, selected from the group consisting of compounds represented by the chemical formulas 2-1 to 2-4: [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 2-3] [Chemical Formula 2-4] .

7. In claim 1, A lithium secondary battery, wherein in the chemical formula 3 above, R2 and R3 are each independently an alkylene group having 1 to 5 carbon atoms, and R4 is an alkyl group having 3 to 20 carbon atoms substituted with one or more fluorines.

8. In claim 1, A lithium secondary battery, wherein in the chemical formula 3 above, R4 is an alkyl group having 4 to 8 carbon atoms substituted with one or more fluorines.

9. In claim 1, The compound represented by the above chemical formula 3 is a lithium secondary battery including a compound represented by the following chemical formula 3-1: [Chemical Formula 3-1] .

10. In claim 1, The loading amount of the above anode is about 500mg / 25cm 2 600mg / 25cm 2 Lithium secondary battery.

11. In claim 1, A lithium secondary battery wherein the non-aqueous electrolyte further comprises vinylene carbonate.

12. In claim 1, A lithium secondary battery wherein the organic solvent comprises a cyclic carbonate solvent and a linear carbonate solvent.

13. In claim 12, The above linear carbonate is a lithium secondary battery containing dimethyl carbonate.

14. In claim 1, The lithium iron phosphate particles are lithium secondary batteries comprising a compound represented by the following chemical formula A: [Chemical Formula A] Li 1+a Fe 1-s M s (PO 4-b )X b In the chemical formula A, M is one or more elements selected from Co, Ni, Mn, Al, Mg, Ti, and V, X is F, S, or N, and 0≤s≤0.5; -0.5≤a≤+0.5; 0≤b≤0.

1.

15. In claim 1, The above lithium iron phosphate particles are lithium secondary batteries containing LiFePO4.

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