Lithium secondary battery

Abstract

The present invention relates to a lithium secondary battery comprising: an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; an electrolyte; and a battery case in which the electrode assembly and the electrolyte are accommodated, wherein: the positive electrode includes, as a positive electrode active material, a lithium nickel-based oxide containing 80 mol% or more of nickel, among all metals except lithium; the lithium nickel-based oxide includes single particle-type particles, secondary particles, or a combination thereof; the negative electrode includes at least one selected from the group consisting of natural graphite and artificial graphite; and the TS index (unit: g / m2), as defined by equation 1, is 1.72 or smaller. In equation 1, the variables are as described in the specification.

Description

Lithium secondary battery Cross-citation with related applications This application claims the benefit of priority from Korean Patent Application No. 10-2023-0188774, filed December 21, 2023, the entire contents of which are incorporated herein by reference. Technical field The present invention relates to a lithium secondary battery, and more specifically, to a lithium secondary battery having excellent thermal safety. Lithium secondary batteries are widely used in various applications such as portable electronic devices, electric vehicles, and energy storage devices due to their high energy density and excellent performance. Accordingly, high energy density characteristics and thermal safety are emerging as important issues for lithium secondary batteries. Specifically, lithium secondary batteries can experience rapid increases in internal temperature due to various causes such as overcharge, overdischarge, external impact, or internal short circuit, and such temperature increase can accelerate chemical reactions inside the battery, causing thermal runaway. Thermal runaway can lead to ignition or explosion of the battery as exothermic reactions occurring inside the battery progress in a chain, which can pose a serious threat to user safety. In addition, lithium secondary batteries with poor thermal stability can shorten the life of the battery, reduce performance, and significantly reduce product reliability. In particular, the importance of thermal safety issues is further highlighted in applications where high-capacity batteries are used, such as electric vehicles. Therefore, there is a need to develop technology that can improve the thermal safety of lithium secondary batteries. The present invention is intended to solve the above problems and to provide a lithium secondary battery having excellent thermal safety. [1] The present invention relates to a lithium secondary battery, comprising: an electrode assembly including a cathode, an anode, and a separator interposed between the cathode and the anode; an electrolyte; and a battery case in which the electrode assembly and the electrolyte are accommodated, wherein the cathode comprises a lithium nickel-based oxide containing nickel at 80 mol% or more of total metals excluding lithium as a cathode active material, and the lithium nickel-based oxide comprises single-particle particles, secondary particles, or a combination thereof, and the anode comprises at least one selected from the group consisting of natural graphite and artificial graphite as a cathode active material, and has a TS index (unit: g / m) defined by the following equation 1: 2 ) is 1.72 or less, a lithium secondary battery is provided. [Formula 1] In the above equation 1, P S means the ratio of the weight of the lithium nickel oxide in the form of secondary particles to the total weight of the lithium nickel oxide, and N G means the ratio of the weight of natural graphite to the total weight of the above natural graphite and artificial graphite, and S N is the BET surface area of ​​the above negative active material (unit: m 2 / g), and E means the ratio of the total weight of the electrolyte to the total weight of the lithium secondary battery. [2] The present invention, in the above [1], the P S A lithium secondary battery having an E-value of 0.7 or less is provided. [3] The present invention, in the above [1] or [2], the N G A lithium secondary battery having an efficiency of 0.6 or less is provided. [4] The present invention, in at least one of the above [1] to [3], the S N Silver 1.3m 2 / g to 1.9m 2 / g, provides a lithium secondary battery. [5] The present invention provides a lithium secondary battery, wherein, in at least one of the above [1] to [4], E is 0.08 to 0.13. [6] The present invention provides a lithium secondary battery, wherein, in at least one of the above [1] to [5], the lithium nickel-based oxide is represented by the following chemical formula 1. [Chemical Formula 1] Li a1 [Ni x1 Co y1 Mn z1 M 1 w1 ]O2 In the above chemical formula 1, M 1 is at least one doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and 0.8≤a1≤1.2, 0.8≤x1<1, 0 <y1≤0.2, 0<z1≤0.2, 0≤w1≤0.1이다. [7] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to [6], the battery case is a cylindrical battery case. [8] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to [7], the ratio of diameter (R) to height (H) (R / H) is 0.4 or more. [9] The present invention provides a lithium secondary battery, wherein in at least one of the above [1] to [8], the lithium secondary battery is a 46110 cell, a 48110 cell, a 4880 cell or a 4680 cell.

[0010] The present invention provides a lithium secondary battery, wherein, in at least one of the above [1] to [9], the lithium secondary battery includes a non-conductive portion in which an active material layer is not formed on at least a portion of the positive electrode and the negative electrode, and the non-conductive portion of the positive electrode and the non-conductive portion of the negative electrode are defined as electrode tabs.

[0011] The present invention provides a lithium secondary battery, wherein, in the above

[0010] , the positive electrode non-coated portion and the negative electrode non-coated portion are formed along the direction in which the electrode assembly is wound on one end of each of the positive and negative electrodes, and a current collecting plate is coupled to each of the positive electrode non-coated portion and the negative electrode non-coated portion, and the current collecting plate is connected to an electrode terminal.

[0012] The present invention provides a lithium secondary battery, wherein, in the above

[0010] or

[0011] , the positive and negative electrode non-conductive parts can be processed into a plurality of independently foldable segments, and at least some of the plurality of segments are folded toward the winding center of the electrode assembly.

[0013] The present invention provides a lithium secondary battery, wherein, in the above

[0012] , at least some of the plurality of folded segments overlap on the upper and lower sides of the electrode assembly, and the current collecting plate is bonded to the plurality of overlapped segments.

[0014] The present invention provides a battery pack including a lithium secondary battery according to one of the above [1] to

[0013] as a unit cell. The lithium secondary battery according to the present invention implements high-capacity characteristics by including a lithium nickel-based oxide containing a high content of lithium among metals other than lithium in a positive electrode active material, and at the same time, by controlling the weight ratio of the lithium nickel-based oxide in the form of secondary particles among the lithium nickel-based oxide, the weight ratio of natural graphite in the negative electrode active material, the BET specific surface area of ​​the negative electrode active material, and the weight ratio of the electrolyte to satisfy specific relationships, thereby allowing heat inside the battery to be quickly discharged to the outside of the battery, thereby improving thermal safety. Figure 1 is a drawing showing a state of lamination before winding of an electrode assembly according to the present invention. FIG. 2 is a cross-sectional view showing the structure of an electrode of an electrode assembly according to one embodiment of the present invention. FIG. 3 is a drawing for explaining the structure of an electrode assembly according to one embodiment of the present invention. FIG. 4 is a cross-sectional view showing the structure of a lithium secondary battery according to one embodiment of the present invention. FIG. 5 is a cross-sectional view showing the structure of a lithium secondary battery according to another embodiment of the present invention. Figure 6 is a drawing for explaining a battery pack according to the present invention. Hereinafter, the present invention will be described in more detail. 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 consistent with 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. The terminology used in this specification is for the purpose of describing exemplary embodiments only and is not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms “include,” “comprising,” or “having” are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof. In the present invention, the term "single particle type" means a particle formed by an aggregation of 30 or fewer sub-particles. The sub-particle unit constituting the single particle type particle is called a nodule. Single particle type particles include a single particle composed of one nodule and a pseudo-single particle which is a composite of 2 to 30 nodules. The above “nodule” is a sub-particle unit that constitutes a single particle and a pseudo-single particle, and may be a single crystal without a crystalline grain boundary, or a polycrystal that has no apparent grain boundary when observed under a field of view of 5,000 to 20,000 times using a scanning electron microscope. In the present invention, a “secondary particle” means a particle formed by an aggregation of more than 30 sub-particles. In order to distinguish it from the sub-particles forming a single particle, the sub-particles forming a secondary particle are called “primary particles.” The expression “particle” used in the present invention may include any one or all of a single particle, a quasi-single particle, a primary particle, a nodule, and a secondary particle. In the present invention, the “specific surface area” is measured by the BET method, and specifically, can be calculated from the nitrogen gas adsorption amount at liquid nitrogen temperature (77K) using BELSORP-mino II of BEL Japan. Recently, with the development of electric vehicle technology, the demand for high-capacity batteries is increasing. In order to develop batteries with such high-capacity characteristics, large cylindrical batteries with increased volume are being developed compared to conventional small cylindrical batteries. However, in the case of large cylindrical batteries, as the size of the battery increases, the amount of heat and gas generated inside the battery increases together, which can cause the battery to catch fire or explode. Meanwhile, in order to increase the capacity of the battery, attempts are increasing to apply high-nickel lithium transition metal oxides with increased nickel content in conventional nickel-cobalt-manganese lithium transition metal oxides as cathode active materials for lithium secondary batteries. However, in the case of high-nickel lithium transition metal oxides, as the nickel content increases, the amount of residual lithium increases, and a side reaction occurs with the electrolyte during the charge / discharge process to generate gas, which may cause explosion and / or ignition of the battery, resulting in a problem of reduced thermal safety. Accordingly, the inventors of the present invention have conducted repeated studies to develop a lithium secondary battery having excellent capacity characteristics and excellent thermal safety, and as a result, they have found that by controlling the weight ratio of the electrolyte to the battery weight so as to satisfy a specific relationship depending on the materials of the positive and negative electrodes, which are indicated by the ratio of secondary particles among the lithium nickel-based oxide included in the positive electrode active material, the ratio of natural graphite among the negative electrode active material, and the BET specific surface area of ​​the negative electrode active material, it is possible to simultaneously improve the capacity characteristics and thermal safety of the battery, thereby completing the present invention. Hereinafter, the present invention will be described in more detail. Lithium secondary battery The lithium secondary battery according to the present invention is a lithium secondary battery including an electrode assembly including a cathode, an anode, and a separator interposed between the cathode and the anode; an electrolyte; and a battery case in which the electrode assembly and the electrolyte are accommodated, wherein the cathode includes a lithium nickel-based oxide including nickel at 80 mol% or more of total metals excluding lithium as a cathode active material, and the lithium nickel-based oxide includes single-particle particles, secondary particles, or a combination thereof, and the anode includes at least one selected from the group consisting of natural graphite and artificial graphite as an anode active material, and has a TS index (unit: g / m) defined by the following equation 1: 2 ) is less than or equal to 1.72. [Formula 1] In the above equation 1, P S means the ratio of the weight of the lithium nickel oxide in the form of secondary particles to the total weight of the lithium nickel oxide, and N G means the ratio of the weight of natural graphite to the total weight of the above natural graphite and artificial graphite, and S N is the BET surface area of ​​the above negative active material (unit: m 2 / g), and E means the ratio of the weight of the electrolyte to the total weight of the lithium secondary battery. Specifically, the TS index defined by the above formula 1 corresponds to a parameter that defines the relationship among the ratio of the weight of the lithium nickel-based oxide in the form of secondary particles to the total weight of the lithium nickel-based oxide, the ratio of the weight of natural graphite to the total weight of the natural graphite and artificial graphite, the BET specific surface area of ​​the negative active material, and the ratio of the weight of the electrolyte to the total weight of the lithium secondary battery, in order to improve the thermal safety of the lithium secondary battery. If the values ​​of the weight ratio of the lithium nickel-based oxide in the form of secondary particles to the total weight of the lithium nickel-based oxide, the weight ratio of the natural graphite to the total weight of the natural graphite and the artificial graphite, the BET specific surface area of ​​the negative electrode active material, and the weight ratio of the electrolyte to the total weight of the lithium secondary battery are each independently excessively high or low, the thermal safety of the lithium secondary battery cannot be sufficiently improved. Accordingly, it is necessary to derive a relationship that can improve thermal safety by complementing each other even if the values ​​of the weight ratio of the lithium nickel-based oxide in the form of secondary particles to the total weight of the lithium nickel-based oxide, the weight ratio of the natural graphite to the total weight of the natural graphite and the artificial graphite, the BET specific surface area of ​​the negative electrode active material, and the weight ratio of the electrolyte to the total weight of the lithium secondary battery are excessively high or low. Accordingly, the present invention expresses the relationship among the weight ratio of the lithium nickel-based oxide in the form of secondary particles with respect to the total weight of the lithium nickel-based oxide, the weight ratio of the natural graphite with respect to the total weight of the natural graphite and artificial graphite, the BET specific surface area of ​​the negative electrode active material, and the weight ratio of the electrolyte with respect to the total weight of the lithium secondary battery as a TS index defined by the above Equation 1, and by mutually adjusting the values ​​of the above components so that the TS index becomes 1.72 or less, the thermal safety of the lithium secondary battery can be improved. The above TS index may be 1.72 or less, preferably 1.60 or less, and more preferably 1.50 or less. When the above range is satisfied, the weight ratio of the secondary particles among the lithium nickel-based oxide included in the positive electrode active material, the weight ratio of the natural graphite among the negative electrode active material, and the weight ratio of the electrolyte to the total weight of the lithium secondary battery depending on the materials of the positive and negative electrodes expressed by the BET specific surface area of ​​the negative electrode active material can be appropriately adjusted, thereby improving the capacity characteristics while reducing the speed of the exothermic reaction occurring in the positive electrode, negative electrode, and electrolyte inside the battery at high temperatures. Accordingly, the amount of gas generated according to the high-temperature exposure time can be reduced, thereby suppressing the temperature increase due to the thermal decomposition reaction, thereby preventing explosion and ignition of the battery due to high-temperature gas, thereby improving the thermal safety of the battery. Above P S means the ratio of the weight of the lithium nickel oxide in the form of secondary particles to the total weight of the lithium nickel oxide. The P S The cross-section of the anode perpendicular to the surface of the anode is observed with a scanning electron microscope (SEM), and the secondary particles and single-particle particles are distinguished from the particle shapes of the secondary particles and single-particle particles, and the volume ratio of the secondary particles and single-particle particles is measured from this, and then the weight ratio of the lithium nickel oxide in the form of secondary particles is calculated to the total weight of the secondary particles and single-particle particles by multiplying the respective densities of the secondary particles and single-particle particles. The P S may be 0.7 or less, preferably 0.6 or less, and more preferably 0.5 or less. When the above range is satisfied, the thermal safety can be excellent while the output characteristics and long-term life characteristics can be excellent, and the processability can be improved. Above N G means the ratio of the weight of natural graphite to the total weight of the above natural graphite and artificial graphite. The above NG The cross-section of the cathode perpendicular to the cathode surface is observed with a scanning electron microscope (SEM), and the artificial graphite and natural graphite are distinguished from each other based on the particle shapes of the artificial graphite and natural graphite, and the volume ratio of the artificial graphite and natural graphite is measured from this, and then the ratio of the weight of the natural graphite to the total weight of the artificial graphite and natural graphite is calculated by multiplying the densities of the artificial graphite and natural graphite, respectively. The N G may be 0.6 or less, preferably 0.1 to 0.6, and more preferably 0.2 to 0.5. When the above range is satisfied, the rapid charging characteristics of the battery are excellent, thermal safety is improved, and adhesive strength is strengthened, thereby improving long-term life characteristics. S above N is the BET surface area of ​​the above negative active material (unit: m 2 / g) means. The above S N The negative electrode containing the above negative active material was scraped into a powder form, and then the nitrogen gas adsorption amount of the powder at liquid nitrogen temperature (77K) was measured using BELSORP-mino II of BEL Japan, thereby obtaining the BET specific surface area (unit: m) of the negative active material. 2 / g) can be obtained. The above S N Silver 1.3m 2 / g to 1.9m 2 / g, preferably 1.4m 2 / g to 1.8m 2 / g, more preferably 1.5m 2 / g to 1.7m 2 / g. When the above range is satisfied, the amount of heat generated and the generation of high-temperature gases can be minimized by optimizing the specific surface area of ​​the cathode material during the chain reaction process that occurs in a high-temperature environment. The above E refers to the ratio of the weight of the electrolyte to the total weight of the lithium secondary battery. In this case, the weight of the electrolyte may be the weight of the electrolyte remaining in the lithium secondary battery after performing the activation process, and the total weight of the lithium secondary battery may be the total weight of the lithium secondary battery after performing the activation process, but is not limited thereto. The above activation refers to a process of charging and / or discharging a lithium secondary battery that has been manufactured but has not been charged or discharged to provide electrical characteristics and forming a solid electrolyte interphase (SEI) film on the electrode to stabilize the battery, thereby making the battery ready for actual use. With respect to the above E, the activation may be achieved by performing the process of charging the lithium secondary battery to a voltage of 4.2 V or higher and discharging to a voltage of 2.5 V or lower at 20 to 70°C three or more times, but is not limited thereto. Specifically, the weight of the electrolyte may mean the sum of the weight of the electrolyte impregnated in the internal pores of the electrode assembly and the weight of the electrolyte located outside the electrode assembly in the internal space of the battery case. For example, the weight of the electrolyte is (1) the weight of the lithium secondary battery after activation, including the electrode assembly, the electrolyte and the battery case, and the battery case is sealed (M L ), (2) a step of disassembling the lithium secondary battery to remove the electrolyte present in the battery case, (3) a step of immersing the battery case and the electrode assembly in a solvent such as dimethyl carbonate to remove the electrolyte present in the surface of the battery case, the surface of the electrode assembly, and the internal pores, and then drying the battery case and the electrode assembly, (4) a step of measuring the weight (M) of the dried battery case. C ) and the weight (M) of the dried electrode assembly A) After going through the step of measuring the measured M L , M C , M A It can be measured by substituting it into Equation A. [Formula A] Weight of the above electrolyte = M L -M C -M A The above E may be 0.08 to 0.13, preferably 0.09 to 0.12, and more preferably 0.095 to 0.11. When the above range is satisfied, the empty space inside the battery is reduced, so that when the amount of gas generated inside the battery reaches a certain level, the opening time of the vent part can be shortened, thereby improving the thermal safety of the lithium secondary battery. Next, each component of the lithium secondary battery according to the present invention will be described in more detail. A lithium secondary battery according to the present invention comprises an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; an electrolyte; and a battery case in which the electrode assembly and the electrolyte are accommodated. (1) Electrode assembly An electrode assembly according to the present invention includes an anode, a cathode, and a separator interposed between the anode and the cathode. The above electrode assembly may be of various forms of electrode assemblies well known in the art, for example, a jelly-roll type, a stack type, a stack and lamination type, or a stack and folding type electrode assembly, and its form is not particularly limited. Preferably, the electrode assembly may be a jelly-roll type electrode assembly. FIG. 1 illustrates a pre-wound laminated structure of an electrode assembly according to one embodiment of the present invention, FIG. 2 illustrates a cross-sectional structure of an electrode plate (positive electrode or negative electrode) according to one embodiment of the present invention, and FIG. 3 illustrates a structure of an electrode assembly according to one embodiment of the present invention. Referring to FIGS. 1 and 2, when the electrode assembly is a jelly-roll type electrode assembly, the electrode assembly (A) of the present invention can be manufactured by winding a laminate formed by sequentially stacking a separator (12), an anode (10), a separator (12), and an anode (11) at least once in one direction (X). Hereinafter, each component of the electrode assembly of the present invention will be described in more detail. 1) Bipolar The above positive electrode can be manufactured by a method of applying positive electrode slurry to one side or both sides of a sheet-shaped positive electrode collector, removing the solvent of the positive electrode slurry through a drying process, and then rolling. Meanwhile, a positive electrode including a non-coated portion can be manufactured by a method of not applying the positive electrode slurry to some area of ​​the positive electrode collector, for example, one end of the positive electrode collector, during the application of the positive electrode slurry. In addition, the cathode slurry can be prepared by dispersing the cathode material according to the present invention in a solvent such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water. The positive electrode manufactured thus includes a positive electrode active material, and specifically, the positive electrode includes a positive electrode current collector; and a positive electrode active material layer; and the positive electrode active material layer may include a positive electrode active material. As the positive electrode collector, various positive electrode collectors used in the relevant technical field can be used. For example, as the positive electrode collector, stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stainless steel surface-treated with carbon, nickel, titanium, silver, etc. can be used. The positive electrode collector can typically have a thickness of 3 to 500 ㎛, 5 to 300 ㎛, or 7 to 200 ㎛, and fine unevenness can be formed on the surface of the positive electrode collector to increase the adhesion of the positive electrode active material. The positive electrode collector can be used in various forms, such as a film, a sheet, a foil, a net, a porous body, a foam, or a non-woven fabric. The above-mentioned positive electrode active material layer may be positioned on the positive electrode current collector, and specifically, may be positioned on one side or both sides of the positive electrode current collector. The above-mentioned positive electrode active material layer may have a single layer or a multilayer structure of two or more layers. The above-described positive electrode active material layer includes a lithium nickel-based oxide containing nickel in an amount of 80 mol% or more, 85 mol% or more, 88 mol% or more, 90 mol% or more, or 92 mol% or more of the total metal excluding lithium as a positive electrode active material. When the above-described lithium nickel-based oxide is included, the capacity of a lithium secondary battery manufactured by including a high nickel content can be excellent. The above lithium nickel-based oxide may be represented by the following chemical formula 1. [Chemical Formula 1] Li a1 [Ni x1 Co y1 Mn z1 M 1 w1 ]O2 In the above chemical formula 1, M 1M may be at least one doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, or may be at least one doping element selected from the group consisting of W, Y, Ba, Ca, Ti, Mg, Ta, and Nb. 1 When including, the structural stability of the lithium nickel-based oxide can be improved. Also, in the chemical formula 1, 0.8≤a1≤1.2, 0.8≤x1<1, 0 <y1≤0.2, 0<z1≤0.2, 0≤w1≤0.1일 수 있다. Specifically, the above a1 may mean a molar ratio of lithium (Li) in the lithium nickel-based oxide represented by the above chemical formula 1, and may be 0.8≤a1≤1.2, 0.9≤a1≤1.15, or 1.0≤a1≤1.1. When the above range is satisfied, a balance between the remarkable effect of improving the capacity characteristics of the positive electrode active material according to the Li content control and the sinterability during the manufacture of the positive electrode active material can be achieved. The above x1 may mean the molar ratio of nickel among the total metal excluding lithium in the lithium nickel-based oxide represented by the above chemical formula 1, and may be 0.80≤x1<1, 0.88≤x1<1, 0.90≤x1<1, or 0.92≤x1<1. When the above range is satisfied, a nickel content sufficient to contribute to charge and discharge in the lithium nickel-based oxide is secured, thereby promoting high capacity. The above y1 may mean the molar ratio of cobalt among the total metals excluding lithium in the lithium nickel oxide represented by the above chemical formula 1, and 0 <y1≤0.2, 0<y1≤0.18, 또는 0.01≤y1≤0.15일 수 있다. 상기 범위를 만족할 경우, 코발트를 적은 함량으로 포함하여 비용적인 이점을 가지면서도 양호한 저항 특성 및 출력 특성을 구현할 수 있다. The above z1 may mean the molar ratio of manganese among the total metals excluding lithium in the lithium nickel oxide represented by the above chemical formula 1, and 0 <z1≤0.2, 0<z1≤0.18, 또는 0.01≤z1≤0.15일 수 있다. 상기 범위를 만족할 경우, 리튬 니켈계 산화물의 구조적 안정성을 향상시킬 수 있다. The above w1 is M among all metals except lithium in the lithium nickel oxide represented by the above chemical formula 1. 1 The molar ratio may be 0≤w1≤0.1, 0≤w1≤0.08, or 0≤w1≤0.05. When the above range is satisfied, the structural stability and energy density of the lithium nickel-based oxide can be improved. The above lithium nickel-based oxide may include single particles, secondary particles, or a combination thereof. When the lithium nickel-based oxide contains single-particle particles, the particle breakage is reduced during rolling and the side reaction with the electrolyte is reduced, so the amount of gas generated at high temperatures is reduced, which reduces the risk of breakage of the separator, electrolyte leakage, etc., and the risk of explosion of the battery at high temperatures can be reduced, so the thermal safety of the battery can be improved, and the storage characteristics can be excellent because self-discharge is reduced. However, if the lithium nickel-based oxide contains only single-particle particles, there may be difficulties in the manufacturing process of a lithium secondary battery due to the generation of high precipitation, the specific surface area is small, which reduces electrolyte impregnation, and the lithium movement path becomes long, which reduces the mobility of lithium ions, so there are problems of reduced resistance characteristics and output characteristics and reduced long-term lifespan. Therefore, the lithium secondary battery according to the present invention comprises a lithium nickel-based oxide having a single particle type, a secondary particle type, or a combination thereof, wherein, depending on the weight ratio of the lithium nickel-based oxide in the form of secondary particles included in the lithium nickel-based oxide, the TS index defined by the above formula 1 is N such that the TS index is 1.72 or less. G , S N By controlling the E values, the thermal safety and life characteristics can be improved while the resistance characteristics, output characteristics, and fairness can be improved. Meanwhile, the average particle diameter (D) of the secondary particle-type lithium nickel oxide among the above cathode active materials 50 ) may be 11 ㎛ to 20 ㎛, preferably 12 ㎛ to 15 ㎛, more preferably 13 ㎛ to 14 ㎛. The average particle diameter (D) of the single particle lithium nickel-based oxide among the positive electrode active materials 50 ) may be 3 ㎛ to 6 ㎛, preferably 3.5 ㎛ to 5.5 ㎛, and more preferably 4 ㎛ to 5 ㎛. When the above range is satisfied, side reactions with the electrolyte can be minimized while preventing an increase in resistance and a decrease in output characteristics, thereby improving the safety and life characteristics of the battery. The above-mentioned positive electrode active material layer may contain 80 wt% to 99.9 wt% of the positive electrode active material, preferably 90 wt% to 99.9 wt%, and more preferably 95 wt% to 99.9 wt%. Meanwhile, the positive electrode active material layer may optionally further include at least one of a positive electrode conductive material and a positive electrode binder. The above-described positive electrode conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without special restrictions. Specific examples include graphite such as natural graphite or artificial graphite; carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, carbon fiber, carbon nanotube, etc.; metal powder or metal fiber such as copper, nickel, aluminum, silver, etc.; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, etc., and one of these may be used alone or a mixture of two or more may be used. The positive electrode conductive material may be typically included in an amount of 0.1 to 30 wt%, preferably 0.3 to 20 wt%, more preferably 0.5 to 10 wt%, and more preferably 0.7 to 5 wt%, based on the total weight of the positive electrode active material layer. The above positive electrode binder serves to improve the adhesion between positive electrode particles and the adhesive strength between the positive electrode and the positive electrode current collector, and specific examples thereof include a fluorine resin binder including polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE); a rubber binder including styrene butadiene rubber (SBR), acrylonitrile-butadiene rubber, and styrene-isoprene rubber; a cellulose binder including carboxyl methyl cellulose (CMC), starch, hydroxy propyl cellulose, and regenerated cellulose; a polyalcohol binder including polyvinyl alcohol; a polyolefin binder including polyethylene and polypropylene; a polyimide binder; and a polyester binder. And silane binders, etc. can be mentioned, and one of these can be used alone or a mixture of two or more can be used. The positive electrode binder can be included in an amount of 0.1 to 30 wt%, preferably 0.3 to 20 wt%, more preferably 0.5 to 10 wt%, and more preferably 0.7 to 5 wt% based on the total weight of the positive electrode active material layer. 2) Cathode The above negative electrode can be manufactured by a method of applying negative electrode slurry to one side or both sides of a long sheet-shaped negative electrode collector, removing the solvent of the negative electrode slurry through a drying process, and then rolling. Meanwhile, a negative electrode including a non-coated region can be manufactured by a method of not applying the negative electrode slurry to some areas of the negative electrode collector, for example, one end of the negative electrode collector, during the application of the negative electrode slurry. The above negative electrode slurry can be prepared by dispersing the negative electrode active material in a solvent such as distilled water, ethanol, methanol, or isopropyl alcohol. Alternatively, the cathode may be manufactured by casting the cathode slurry onto a separate support, peeling the film from the support, and laminating the resulting film onto a cathode current collector. The above negative electrode includes a negative electrode active material, and specifically, includes the negative electrode current collector; and a negative electrode active material layer; and the negative electrode active material layer may include a negative electrode active material. The above negative electrode current collector is not particularly limited as long as it has high conductivity without causing a chemical change in the battery, and for example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface-treated with carbon, nickel, titanium, silver, etc., aluminum-cadmium alloy, etc. can be used. The above negative electrode current collector can typically have a thickness of 3 to 500 ㎛, 5 to 300 ㎛, or 7 to 200 ㎛. In addition, the negative current collector, like the positive current collector, can form fine irregularities on the surface of the negative current collector to strengthen the bonding strength of the negative active material. For example, it can be used in various forms such as a film, sheet, foil, net, porous body, foam, and non-woven fabric. The negative electrode active material layer may be positioned on the negative electrode current collector, and specifically, may be positioned on one side or both sides of the negative electrode current collector. The negative electrode active material layer may have a single layer or a multilayer structure of two or more layers. The above-described negative electrode active material layer includes at least one selected from the group consisting of natural graphite and artificial graphite as the negative electrode active material. The present invention controls the material of the negative electrode active material so that the TS index represented by the above-described formula 1 becomes 1.72 or less, thereby enabling the lithium secondary battery to be manufactured with excellent capacity characteristics, life characteristics, and thermal safety, while being advantageous in terms of cost. The above negative active material layer may contain 80 wt% to 99.9 wt% of the negative active material, preferably 90 wt% to 99.5 wt%, more preferably 95 wt% to 99.9 wt%, and even more preferably 97 wt% to 99.9 wt%. Meanwhile, the negative electrode active material layer may optionally further include a negative electrode conductive material and a negative electrode binder in addition to the negative electrode active material. The above-described negative electrode conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without special restrictions. Specific examples include graphite such as natural graphite or artificial graphite; carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, carbon fiber, carbon nanotube, etc.; metal powder or metal fiber such as copper, nickel, aluminum, silver, etc.; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, etc., and one of these may be used alone or a mixture of two or more may be used. The above-described negative electrode conductive material may be typically included in an amount of 0.1 to 30 wt%, preferably 0.3 to 20 wt%, more preferably 0.5 to 10 wt%, and more preferably 0.7 to 5 wt%, based on the total weight of the negative electrode active material layer. The above negative electrode binder serves to improve the adhesion between negative electrode active material particles and the adhesive strength between the negative electrode active material and the negative electrode current collector. Specific examples thereof include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated-EPDM, styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof may be used. The above negative electrode binder may be included in an amount of 0.1 to 30 wt%, preferably 0.3 to 20 wt%, more preferably 0.5 to 10 wt%, and more preferably 0.7 to 5 wt%, based on the total weight of the negative electrode active material layer. 3) Membrane Next, the separator is interposed between the negative electrode and the positive electrode to separate the negative electrode and the positive electrode and to provide a passage for lithium ions to move. If it is commonly used as a separator in a lithium secondary battery, it can be used without any special limitation. Specifically, the separator may be a porous polymer film, 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, or a laminated structure of two or more layers thereof. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, a coated separator containing a ceramic component or a polymer material may be used to secure heat resistance or mechanical strength. Meanwhile, the positive electrode (10) and negative electrode (11) have a structure in which an active material layer (21) is formed on a sheet-shaped current collector (20), and may include a non-conductive portion (22) in which the active material layer (21) is not formed in some area of ​​the current collector (20). As described above, by using a positive electrode (10) and a negative electrode (11) including a non-conductive portion (22), a battery having a structure in which at least a portion of the non-conductive portion of the positive electrode (10) and negative electrode (11) defines an electrode tab can be implemented without providing a separate electrode tab. Specifically, the non-conductive portion (22) can be formed long along the winding direction (X) at one end of the current collector (20), and a current collecting plate is combined with each of the positive non-conductive portion and the negative non-conductive portion, and the current collecting plate is connected to an electrode terminal, thereby functioning as an electrode tab. For example, a battery in which the positive electrode non-coated portion and the negative electrode non-coated portion function as electrode tabs can be manufactured by the following method. First, a separator, a positive electrode, a separator, and a negative electrode are sequentially laminated so that the positive electrode non-coated portion and the negative electrode non-coated portion are positioned in opposite directions, and then wound in one direction to manufacture a jelly-roll type electrode assembly. Then, the positive and negative electrode non-coated portions are folded toward the winding center (C), and then current collector plates are welded to the positive electrode non-coated portion and the negative electrode non-coated portion respectively to join them, and the current collector plates are connected to electrode terminals to manufacture a battery. The current collector plates have a larger cross-sectional area than the strip-type electrode tabs, and since resistance is inversely proportional to the cross-sectional area of ​​a path through which current flows, when a secondary battery is formed with the above structure, the cell resistance can be significantly reduced. Meanwhile, the positive and negative electrode portions may be processed into a plurality of independently foldable segments, and at least some of the plurality of segments may be folded toward the winding center (C) of the electrode assembly. The above segments can be formed by processing the positive and negative current collectors through a metal foil cutting process such as laser notching, ultrasonic cutting, or punching. When the non-conductive portions of the positive and negative electrodes are processed in the form of multiple segments, the stress applied to the non-conductive portion during bending can be reduced, thereby preventing deformation or damage to the non-conductive portion, and improving the welding characteristics with the current collecting plate. The collector plate and the plain portion are generally joined by welding. In order to improve the welding characteristics, strong pressure should be applied to the welding area of ​​the plain portion to fold the plain portion as flat as possible. However, during this bending process, the shape of the plain portion may be distorted and deformed irregularly, and the deformed portion may come into contact with an electrode of the opposite polarity, causing an internal short circuit or inducing micro-cracks in the plain portion. However, if the plain portions of the positive and negative electrodes are processed into a plurality of independently bendable segments, the stress applied to the plain portion during bending can be relieved, thereby minimizing deformation and damage to the plain portion. In addition, when the non-conductive portion is processed in the form of segments as described above, overlap occurs between the plurality of segments during folding, which increases the welding strength with the current collector plate, and when using the latest technology such as laser welding, it is possible to prevent the problem of the laser penetrating into the electrode assembly and melting away the separator or active material. Preferably, at least some of the plurality of folded segments may overlap on the upper and lower sides of the electrode assembly, and the current collector plate may be bonded on the plurality of overlapped segments. Meanwhile, the electrode assembly according to the present invention may be formed with a structure in which an insulating layer (24) is additionally formed on the positive electrode (10), as illustrated in FIG. 3. Specifically, the insulating layer (24) may be formed to cover a portion of the positive electrode active material layer and a portion of the non-conductive portion along a direction parallel to the winding direction of the electrode assembly. In the case of a battery having a tab-less structure in which the non-conductive portion (22c) of the positive electrode (10) and the non-conductive portion (22a) of the negative electrode (11) are used as electrode tabs, an electrode assembly is formed so that the positive electrode (10) protrudes above the separator (12) and the negative electrode (11) protrudes below the separator (12), and the protruding positive electrode (10) and / or negative electrode (11) are folded and then combined with a current collecting plate. However, when the positive electrode (10) or negative electrode (11) is folded as described above, the current collector of the positive electrode (10) or negative electrode (11) is positioned close to an electrode of the opposite polarity beyond the separator, which may cause the positive electrode and negative electrode to come into electrical contact, thereby causing an internal short circuit. However, as shown in Fig. 5, when an insulating layer (24) covering the positive electrode active material layer and a portion of the non-conductive portion is formed, the positive electrode (10) and the negative electrode (11) can be prevented from electrically contacting each other by the insulating layer (24), thereby preventing a short circuit from occurring inside the battery. Preferably, the insulating layer (24) may be provided on at least one surface of the positive electrode (10) current collector, and preferably, may be provided on both surfaces of the positive electrode (10). In addition, the insulating layer (24) may be formed in an area of ​​the positive electrode (10) that is likely to face the active material layer (21a) of the negative electrode (11). For example, in the case of the non-coated portion (22c) of the positive electrode (10) that faces the negative electrode (11) after being folded, the insulating layer (24) may be formed to extend to the end of the non-coated portion (22c). However, in the case of the opposite side of the surface that faces the negative electrode (11) after being folded, it is preferable that the insulating layer (24) be formed only in a part of the non-coated portion (22c), for example, up to the point before the bending of the non-coated portion (22c). This is because, if the insulating layer (24) is formed in the entire area of ​​the non-coated portion on the opposite side of the surface that faces the negative electrode (11), electrical contact with the current collecting plate is impossible, and thus, it cannot function as an electrode tab. Meanwhile, the insulating layer (24) can be attached to the anode while securing insulating performance, and its material or component is not particularly limited. For example, the insulating layer can be an insulating coating layer or an insulating tape, and the insulating coating layer can include an organic binder and inorganic particles. At this time, the organic binder can be, for example, styrene-butadiene rubber (SBR), and the inorganic particles can be, but are not limited to, alumina oxide. (2) Battery case The above battery case is for accommodating the electrode assembly and the electrolyte, and various battery cases known in the art, such as a cylindrical battery case, a square battery case, a pouch-type battery case, etc., can be used. Preferably, the battery case may be a cylindrical battery case. When the above battery case is a cylindrical battery case, the ratio of the diameter (R) to the height (H) (R / H) (ratio of the form factor) may be 0.4 or more, preferably 0.4 to 0.8, more preferably 0.5 to 0.7. When the above range is satisfied, when combined with a configuration that satisfies the high-capacity characteristic and has a TS index defined by the above formula 1 of 1.72 or less, the effect of improving the thermal safety of the lithium secondary battery can be further maximized. In addition, the lithium secondary battery according to the present invention may be, for example, a 46110 cell (diameter 46 mm, height 110 mm, form factor ratio 0.418), a 4875 cell (diameter 48 mm, height 75 mm, form factor ratio 0.640), a 48110 cell (diameter 48 mm, height 110 mm, form factor ratio 0.436), a 4880 cell (diameter 48 mm, height 80 mm, form factor ratio 0.600), a 4680 cell (diameter 46 mm, height 80 mm, form factor ratio 0.575), a 4695 cell (diameter 46 mm, height 95 mm, form factor ratio 0.484). In the numerical value indicating the form factor, the first two numbers indicate the diameter (R) of the lithium secondary battery, and the next two or three numbers indicate the height (H) of the lithium secondary battery. If the above range is satisfied, high-capacity characteristics can be implemented. (3) Electrolyte The electrolyte according to the present invention may include a lithium salt and an organic solvent. The lithium salt may be used without any particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, the lithium salt may be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2. LiCl, LiI, or LiB(C2O4)2. It is preferable to use the concentration of the lithium salt in the range of 0.1 to 5.0 M, preferably 0.1 to 3.0 M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively. The above organic solvent may include at least one of a cyclic carbonate-based organic solvent, a linear carbonate-based organic solvent, a linear ester-based organic solvent, and a cyclic ester-based organic solvent. The above cyclic carbonate-based organic solvent is a high-viscosity organic solvent, and may include at least one organic solvent selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and vinylene carbonate. In addition, the linear carbonate-based organic solvent is an organic solvent having low viscosity and low dielectric constant, and representative examples thereof include at least one organic solvent selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate, and ethyl propyl carbonate, and specifically, ethyl methyl carbonate (EMC) may be included. Specific examples of the linear ester organic solvent include at least one organic solvent selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate. The above cyclic ester organic solvent may include at least one organic solvent selected from the group consisting of γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone. Preferably, the electrolyte according to the present invention may include ethylene carbonate and dimethyl carbonate as organic solvents. Meanwhile, in addition to the electrolyte components, the electrolyte may additionally contain other additives for the purposes of improving the life characteristics of the battery, suppressing battery capacity reduction, and improving the discharge capacity of the battery. These other additives may include at least one other additive selected from the group consisting of, for example, cyclic carbonate compounds, halogen-substituted carbonate compounds, sultone compounds, sulfate compounds, borate compounds, nitrile compounds, benzene compounds, amine compounds, silane compounds, and lithium salt compounds different from the lithium salt included in the electrolyte. Specifically, the other additives include vinylene carbonate (VC), vinylethylene carbonate, fluoroethylene carbonate (FEC), 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, 1,3-propene sultone (PRS), 1,4-butene sultone, 1-methyl-1,3-propene sultone, ethylene sulfate (ESA), trimethylene sulfate (TMS), methyl trimethylene sulfate (MTMS), tetraphenylborate, lithium oxalyldifluoroborate, succinonitrile, adiponitrile, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentane carbonitrile, cyclohexane carbonitrile, The present invention relates to a compound selected from the group consisting of 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, 4-fluorophenylacetonitrile, fluorobenzene, triethanolamine, ethylenediamine, tetravinylsilane, LiN(SO2F)2(lithium bis(fluorosulfonyl)imide, LiFSI), LiN(SO2CF3)2(lithium bis(trifluoromethane sulfonyl)imide, LiTFSI), LiPO2F2, LiODFB, LiBOB (lithium bisoxalatoborate (LiB(C2O4)2) and LiBF4. The above other additives may be included in an amount of 0.01 to 20 wt% based on the total weight of the electrolyte, and preferably 0.05 to 5.0 wt%. If the content of the above other additives is less than 0.01 wt%, the effects of improving the low-temperature output of the battery and the high-temperature storage characteristics and high-temperature life characteristics are minimal, and if the content of the above other additives exceeds 20 wt%, there is a possibility that side reactions may occur excessively in the electrolyte during charge and discharge of the battery. In particular, when the above SEI film-forming additives are added in excessive amounts, they may not be sufficiently decomposed at high temperatures and may exist as unreacted substances or in a precipitated state in the electrolyte at room temperature. Accordingly, side reactions that reduce the life or resistance characteristics of the secondary battery may occur. Next, the structure of a lithium secondary battery according to the present invention will be described. FIGS. 4 and 5 disclose implementation examples of lithium secondary batteries according to the present invention. Hereinafter, a lithium secondary battery according to the present invention will be described with reference to FIGS. 4 and 5. However, FIGS. 4 and 5 only show one embodiment of the present invention, and the structure of the battery of the present invention is not limited to the range disclosed in FIGS. 4 and 5. FIG. 4 illustrates a cross-sectional view of a lithium secondary battery having a tab-less structure according to one embodiment of the present invention. Referring to FIG. 4, a lithium secondary battery (140) according to the present invention may include an electrode assembly (141), a battery case (142) in which the electrode assembly (141) and an electrolyte (not shown) are stored, and a sealing body (143) that seals an open end of the battery case (142). At this time, the electrode assembly may be a laminate of a positive electrode, a separator, and a negative electrode, which is wound in one direction. In addition, the positive electrode and the negative electrode of the electrode assembly may each include a non-coated portion on which an active material layer is not formed, and may be laminated and wound such that the positive electrode non-coated portion and the negative electrode non-coated portion are positioned at the top and bottom of the electrode assembly, respectively. Since the electrode assembly has been described above, only the remaining components excluding the electrode assembly will be described below. Meanwhile, the battery case (142) is a can-shaped container with an open end formed at the top, and is made of a conductive metal material such as aluminum or steel. The battery case accommodates an electrode assembly (141) in the inner space through the open end at the top, and also accommodates an electrolyte (not shown). Meanwhile, it is preferable that the lithium secondary battery (140) of the present invention does not include a current interruption device (CID). Meanwhile, as illustrated in FIG. 4, the battery case (142) is electrically connected to the negative electrode non-conductive portion (146b) and can function as a negative terminal that contacts an external power source and transmits current applied from the external power source to the negative electrode. If necessary, a beading portion (147) and a crimping portion (148) may be provided on the upper end of the battery case (142). The beading portion (147) may be formed by pressing the outer circumference of the battery case (142) to a distance of D1. The beading portion (147) may prevent the electrode assembly (141) accommodated inside the battery case (142) from coming out through the upper opening of the battery case (142), and may function as a support portion on which the sealing body (143) is secured. The above crimping portion (148) can be formed on the upper portion of the beading portion (147), and has an extended and bent shape to surround the outer surface of the cap plate (143a) placed on the beading portion (147) and a portion of the upper surface of the cap plate (143a). Next, the sealing member (143) is for sealing the open end of the battery case (142), and includes a cap plate (143a), a first gasket (143b) that provides airtightness and insulation between the cap plate (143a) and the battery case (142), and, if necessary, may further include a connecting plate (143c) that is electrically and mechanically coupled to the cap plate (143a). The cap plate (143a) is pressed onto a beading portion (147) formed on the battery case (142), and may be fixed by a crimping portion (148). The cap plate (143a) is a component made of a conductive metal material and covers the upper opening of the battery case (142). The cap plate (143a) is electrically connected to the positive electrode of the electrode assembly (141) and is electrically insulated from the battery case (142) through the first gasket (143b). Therefore, the cap plate (143a) can function as a positive electrode terminal of a lithium secondary battery. The cap plate (143a) can have a protrusion (143d) formed to protrude upward from its center portion C, and the protrusion (143d) can come into contact with an external power source to allow current to be applied from the external power source. A first gasket (143b) may be interposed between the cap plate (143a) and the crimping portion (148) to ensure airtightness of the battery case (142) and to provide electrical insulation between the battery case (142) and the cap plate (143a). Meanwhile, the lithium secondary battery (140) according to the present invention may further include a current collecting plate (144, 145), if necessary. The current collecting plate is coupled to the positive electrode non-conducting portion (146a) and the negative electrode non-conducting portion (146b), and is connected to the electrode terminals (i.e., the positive electrode terminal and the negative electrode terminal). Specifically, a cylindrical battery (140) according to the present invention may include a first current collecting plate (144) coupled to an upper portion of an electrode assembly (141) and a second current collecting plate (145) coupled to a lower portion of the electrode assembly (141). It may further include a first collector plate (144) and / or a second collector plate (145). The first collector plate (144) is coupled to the upper portion of the electrode assembly (141). The first collector plate (144) is made of a conductive metal material such as aluminum, copper, nickel, etc., and is electrically connected to the non-conductive portion (146a) of the positive electrode. A lead (149) may be connected to the first collector plate (144). The lead (149) may extend upward from the electrode assembly (141) and be coupled to the connection plate (143c) or may be directly coupled to the lower surface of the cap plate (143a). The coupling of the lead (149) and other components may be accomplished by welding. Preferably, the first collector plate (144) may be formed integrally with the lead (149). In this case, the lead (149) may have a plate shape that extends outward from the center of the first collector plate (144). Meanwhile, the first collector plate (144) is joined to an end of the non-conductive portion (146a) of the anode, and the joining can be accomplished by, for example, laser welding, resistance welding, ultrasonic welding, soldering, or the like. The second collector plate (145) is coupled to the lower portion of the electrode assembly (141). The second collector plate (145) is made of a conductive metal material such as aluminum, copper, nickel, etc., and is electrically connected to the non-conductive portion (146b) of the negative electrode. One side of the second collector plate (145) can be coupled to the non-conductive portion (146b) of the negative electrode, and the opposite side can be coupled to the inner bottom surface of the battery case (142). At this time, the coupling can be performed by a method such as laser welding, resistance welding, ultrasonic welding, or soldering. Meanwhile, the lithium secondary battery (140) according to the present invention may further include an insulator (146), if necessary. The insulator (146) may be arranged to cover the upper surface of the first current collecting plate (144). Since the insulator (146) covers the first current collecting plate (144), direct contact between the first current collecting plate (144) and the inner surface of the battery case (142) can be prevented. The insulator (146) is provided with a lead hole (151) through which a lead (149) extending upward from the first collector plate (144) can be drawn out. The lead (149) is drawn upward through the lead hole (151) and coupled to the lower surface of the connecting plate (143c) or the lower surface of the cap plate (143a). The insulator (146) may be made of a polymer resin material having insulating properties, such as polyethylene, polypropylene, polyimide, or polybutylene terephthalate. Meanwhile, the lithium secondary battery (140) according to the present invention may further include a venting portion (152) formed on the lower surface of the battery case (142), if necessary. The venting portion (152) corresponds to a region of the lower surface of the battery case (142) that has a thinner thickness than the surrounding region. Since the venting portion (152) is thin, it is structurally weaker than the surrounding region. Therefore, when the pressure inside the lithium secondary battery (140) increases above a certain level, the venting portion (152) ruptures, thereby allowing gas inside the battery case (152) to be discharged to the outside, thereby preventing the battery from exploding. FIG. 5 illustrates a cross-sectional view of a lithium secondary battery having a tab-less structure according to another embodiment of the present invention. Referring to FIG. 5, a lithium secondary battery (170) according to another embodiment of the present invention has a different structure of a battery case and a sealant compared to the lithium secondary battery (140) illustrated in FIG. 4, and the configuration of the electrode assembly and the electrolyte are substantially the same. Specifically, a lithium secondary battery (170) according to another embodiment of the present invention includes a battery case (171) having a rivet terminal (172) installed therethrough. The rivet terminal (172) is installed in a partially closed closed surface (upper surface in the drawing) of one end of the battery case (171). The rivet terminal (172) is riveted to a through hole (first opening of the first end) of the battery case (171) while an insulating second gasket (173) is interposed therebetween. The rivet terminal (172) is exposed to the outside in a direction opposite to the gravity direction. The rivet terminal (172) includes a terminal exposure portion (172a) and a terminal insertion portion (172b). The terminal exposure portion (172a) is exposed to the outside of the closed surface of the battery case (171). The terminal exposure portion (172a) may be located approximately at the center of the partially closed surface of the battery case (171). The maximum diameter of the terminal exposure portion (172a) may be formed larger than the maximum diameter of the through hole formed in the battery case (171). The terminal insertion portion (172b) may penetrate approximately at the center of the closed surface of the battery case (171) and be electrically connected to the non-conductive portion (146a) of the positive electrode. The terminal insertion portion (172b) may be riveted onto the inner surface of the battery case (171). That is, an end of the terminal insertion portion (172b) may have a shape that is bent toward the inner surface of the battery case (171). The maximum diameter of the end of the terminal insertion portion (172b) may be larger than the maximum diameter of the through hole of the battery case (171). The lower surface of the terminal insertion portion (172b) can be welded with the first current collecting plate (144) connected to the non-polar portion (146a) of the positive electrode. An insulating cap (174) made of an insulating material can be interposed between the first current collecting plate (144) and the inner surface of the battery case (171). The insulating cap (174) covers the upper portion of the first current collecting plate (144) and the upper edge portion of the electrode assembly (141). This prevents the outer non-polar portion (B3) of the electrode assembly (141) from coming into contact with the inner surface of the battery case (171) having a different polarity, thereby causing a short circuit. The terminal insertion portion (172b) of the rivet terminal (172) can be welded to the first current collecting plate (144) by penetrating the insulating cap (174). The second gasket (173) is interposed between the battery case (171) and the rivet terminal (172) to prevent the battery case (171) and the rivet terminal (172) having opposite polarities from electrically contacting each other. As a result, the upper surface of the battery case (171) having a substantially flat shape can function as a positive terminal of the lithium secondary battery (170). The second gasket (173) includes a gasket exposure portion (173a) and a gasket insertion portion (173b). The gasket exposure portion (173a) is interposed between the terminal exposure portion (172a) of the rivet terminal (172) and the battery case (171). The gasket insertion portion (173b) is interposed between the terminal insertion portion (172b) of the rivet terminal (172) and the battery case (171). The gasket insertion portion (173b) can be deformed together with the terminal insertion portion (172b) during riveting so as to be in close contact with the inner surface of the battery case (171). The second gasket (173) can be made of, for example, an insulating polymer resin. The gasket exposure portion (173a) of the second gasket (173) may have an extended shape so as to cover the outer surface of the terminal exposure portion (172a) of the rivet terminal (172). When the second gasket (173) covers the outer surface of the rivet terminal (172), a short circuit can be prevented from occurring during the process of connecting an electrical connection component such as a bus bar to the upper surface of the battery case (171) and / or the rivet terminal (172). Although not shown in the drawing, the gasket exposure portion (173a) may have an extended shape so as to cover not only the outer surface of the terminal exposure portion (172a) but also a part of the upper surface. In the case where the second gasket (173) is made of a polymer resin, the second gasket (173) can be joined to the battery case (171) and the rivet terminal (172) by heat fusion. In this case, the sealing at the joining interface between the second gasket (173) and the rivet terminal (172) and the joining interface between the second gasket (173) and the battery case (171) can be strengthened. Meanwhile, in the case where the gasket exposure portion (173a) of the second gasket (173) has a form that extends to the upper surface of the terminal exposure portion (172a), the rivet terminal (172) can be joined integrally with the second gasket (173) by insert injection. The remaining area (175) of the upper surface of the battery case (171), excluding the area occupied by the rivet terminal (172) and the second gasket (173), corresponds to a negative terminal having the opposite polarity to the rivet terminal (172). The second collector plate (176) is coupled to the lower portion of the electrode assembly (141). The second collector plate (176) is made of a conductive metal material such as aluminum, steel, copper, or nickel, and is electrically connected to the unconducted portion (146b) of the cathode. Preferably, the second collector plate (176) is electrically connected to the battery case (171). To this end, at least a portion of an edge portion of the second collector plate (176) may be interposed and fixed between the inner surface of the battery case (171) and the first gasket (178b). In one example, at least a portion of an edge portion of the second collector plate (176) may be fixed to the beading portion (180) formed at the lower end of the battery case (171) by welding while being supported by the lower surface of the beading portion (180). In a variation, at least a portion of an edge portion of the second collector plate (176) may be directly welded to the inner wall surface of the battery case (171). The second collector plate (176) may have a plurality of protrusions (not shown) formed radially on a surface facing the non-conductive portion (146b). When the protrusions are formed, the second collector plate (176) may be pressed to press the protrusions into the non-conductive portion (146b). Preferably, the ends of the second collector plate (176) and the non-conductive portion (146b) can be joined by welding, for example, laser welding. A sealing member (178) for sealing the lower open end of the battery case (171) includes a cap plate (178a) and a first gasket (178b). The first gasket (178b) electrically separates the cap plate (178a) and the battery case (171). A crimping member (181) secures the edge of the cap plate (178a) and the first gasket (178b) together. A vent member (179) is provided in the cap plate (178a). The configuration of the vent member (179) is substantially the same as in the above-described embodiment. Preferably, the cap plate (178a) is made of a conductive metal material. However, since a first gasket (178b) is interposed between the cap plate (178a) and the battery case (171), the cap plate (178a) does not have electrical polarity. The sealing body (178) seals the open end of the lower portion of the battery case (171) and discharges gas when the internal pressure of the battery cell (170) increases above a critical value. Preferably, the rivet terminal (172) electrically connected to the non-conductive portion (146a) of the positive electrode is used as the positive terminal. In addition, a portion (175) of the upper surface of the battery case (171) electrically connected to the non-conductive portion (146b) of the negative electrode through the second current collecting plate (176), excluding the rivet terminal (172), is used as the negative terminal. In this way, when the two electrode terminals are positioned on the upper portion of the lithium secondary battery, it is possible to place electrical connection components such as bus bars on only one side of the lithium secondary battery (170). This can lead to simplification of the battery pack structure and improvement of energy density. In addition, since the portion (175) used as the negative terminal has a substantially flat shape, a sufficient connection area can be secured when connecting electrical connection components such as bus bars. Accordingly, the lithium secondary battery (170) can lower the resistance at the connection portion of the electrical connection components to a desirable level. When a lithium secondary battery is formed with a tab-less structure as described above, since current concentration is less than that of a conventional battery having electrode tabs, heat generation inside the battery can be effectively reduced, thereby improving the thermal safety of the battery. In addition, when the lithium secondary battery according to the present invention has a tab-less structure as described above, the effect of improving thermal safety can be maximized when combined with a configuration in which the TS index defined by Equation 1 is 1.72 or less. Battery pack The lithium secondary battery of the present invention as described above can be included as a unit cell in manufacturing a battery pack. FIG. 6 schematically illustrates the configuration of a battery pack according to an embodiment of the present invention. Referring to FIG. 6, a battery pack (3) according to an embodiment of the present invention includes an assembly of lithium secondary batteries (1) electrically connected thereto and a pack housing (2) accommodating the assembly. The lithium secondary battery (1) is a lithium secondary battery according to the embodiment described above. In the drawing, for the convenience of illustration, parts such as a bus bar, a cooling unit, and an external terminal for electrically connecting the lithium secondary batteries (1) are omitted. The above battery pack (3) can be mounted on a vehicle. The vehicle may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle includes a four-wheel vehicle or a two-wheel vehicle. The present invention will be described more specifically through specific examples below. Example 1 <Polar manufacturing> A cathode slurry was prepared by adding a cathode active material, a conductive agent, and a binder to N-methylpyrrolidone at a weight ratio of 97:1:2. At this time, the cathode active material was Li2[Ni, which is a single particle. 0.93 Co 0.05 Mn 0.02 ]O2 was used, CNT was used as a challenge material, and PVDF was used as a binder. The above positive electrode slurry was applied onto an aluminum current collector, dried, and then roll pressed to manufacture a positive electrode. <Cathode Manufacturing> A negative electrode slurry was prepared by adding a negative electrode active material, a conductive agent, a binder, and a thickener to distilled water at a weight ratio of 98:0.1:1:0.9. At this time, natural graphite and artificial graphite were mixed at a weight ratio of 6:4 as the negative electrode active material, SW-CNT as the conductive agent, styrene-butadiene rubber (SBR) as the binder, and carboxymethyl cellulose (CMC) as the thickener. The above negative electrode slurry was applied on a copper current collector having a thickness of 10 μm, dried, and then roll-pressed to manufacture a negative electrode including a negative electrode active material layer. At this time, the BET specific surface area of ​​the negative electrode active material was 1.7 m 2 / g was. <Lithium secondary battery manufacturing> A separator was interposed between the positive and negative electrodes manufactured as described above, and the electrodes were laminated in the order of separator / positive electrode / separator / negative electrode, and then wound to manufacture a jelly-roll type electrode assembly. The electrode assembly described above was inserted into a cylindrical battery case having a height of 80 mm and a diameter of 46 mm, and an electrolyte was injected to manufacture a lithium secondary battery (4680 cell). At this time, the electrolyte was manufactured by adding LiPF6 at a molar concentration of 1.25 M to an organic solvent containing ethylene carbonate (EC): ethyl methyl carbonate (EMC): DMC (dimethyl carbonate) in a weight ratio of 20:20:60. At this time, the ratio of the weight of the electrolyte to the total weight of the lithium secondary battery was 0.098. Example 2 <Polar manufacturing> *231 Li2[Ni, a single particle type, is used as a cathode active material 0.93 Co 0.05 Mn 0.02 ]O2 and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]The anode was manufactured in the same manner as in Example 1, except that O2 was mixed and used in a weight ratio of 5:5. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 5:5 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.5 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.105. Example 3 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2- and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]O2- was mixed in a weight ratio of 5:5 and used, but the anode was manufactured in the same manner as in Example 1. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 5:5 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.5 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.098. Example 4 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2- and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]O2- was mixed in a weight ratio of 8:2 and used, but the anode was manufactured in the same manner as in Example 1. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 5:5 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.5 m2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.105. Example 5 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2 and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]The anode was manufactured in the same manner as in Example 1, except that O2 was mixed and used in a weight ratio of 4:6. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 1:9 as the negative active material, and the BET specific surface area of ​​the negative active material was 0.9 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.098. Comparative Example 1 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2- and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]O2- was mixed in a weight ratio of 2:8 and used to manufacture the anode in the same manner as in Example 1. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 3:7 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.2 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.105. Comparative Example 2 <Polar manufacturing> Li2[Ni, a secondary particle, is used as a cathode active material. 0.97 Co 0.005 Mn 0.025 ]The anode was manufactured in the same manner as in Example 1, except that O2- was used. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 6:4 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.7 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.105. Comparative Example 3 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2- and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]O2- was mixed in a weight ratio of 2:8 and used to manufacture the anode in the same manner as in Example 1. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 5:5 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.5 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.105. Comparative Example 4 <Polar manufacturing> Li2[Ni, a secondary particle, is used as a cathode active material. 0.97 Co 0.005 Mn 0.025 ]The anode was manufactured in the same manner as in Example 1 except that O2 was used. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 5:5 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.5 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.105. Comparative Example 5 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2 and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]The anode was manufactured in the same manner as in Example 1, except that O2 was mixed and used in a weight ratio of 5:5. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 5:5 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.5 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.098. Comparative Example 6 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2 and secondary particles Li2[Ni 0.97 Co 0.005 Mn 0.025 ]The anode was manufactured in the same manner as in Example 1, except that O2 was mixed and used in a weight ratio of 5:5. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 7:3 as the negative active material, and the BET specific surface area of ​​the negative active material was 1.5 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.105. Comparative Example 7 <Polar manufacturing> Li2[Ni, a single particle type cathode active material 0.93 Co 0.05 Mn 0.02 ]O2 and secondary particles Li2[Ni 0.97 Co 0.005 Mn0.025 ]The anode was manufactured in the same manner as in Example 1, except that O2 was mixed and used in a weight ratio of 6:4. <Cathode Manufacturing> At this time, natural graphite and artificial graphite were mixed in a weight ratio of 9:1 as the negative active material, and the BET specific surface area of ​​the negative active material was 2.1 m 2 The cathode was manufactured in the same manner as in Example 1 except that / g. <Lithium secondary battery manufacturing> At this time, a lithium secondary battery was manufactured in the same manner as in Example 1, except that the electrolyte was injected so that the weight ratio of the electrolyte to the total weight of the lithium secondary battery was 0.092. Experimental Example 1: Measurement of TS Index For the lithium secondary batteries manufactured in Examples 1 to 5 and Comparative Examples 1 to 7, the TS index defined by Equation 1 below was calculated and shown in Table 1 below. [Formula 1] In the above equation 1, P S means the ratio of the weight of the lithium nickel oxide in the form of secondary particles to the total weight of the lithium nickel oxide, and N G means the ratio of the weight of natural graphite to the total weight of the above natural graphite and artificial graphite, and S N is the BET surface area of ​​the above negative active material (unit: m 2 / g), and E means the ratio of the total weight of the electrolyte to the total weight of the lithium secondary battery. 1) P S measurement The cross-sections of the positive electrodes perpendicular to the positive electrode surface of the lithium secondary batteries manufactured in Examples 1 to 5 and Comparative Examples 1 to 7 were observed using a scanning electron microscope (SEM), and the secondary particles and single-particle particles were distinguished from the particle shapes of the secondary particles and single-particle particles, and the volume ratio of the secondary particles and single-particle particles was measured therefrom. Then, the weight ratio of the secondary particles to the single-particle particles was calculated and measured by multiplying the respective densities of the secondary particles and the single-particle particles to the total weight of the secondary particles and the single-particle particles. The results are shown in Table 1 below. 2) N G measurement The cross-sections of the negative electrodes perpendicular to the negative electrode surfaces of the lithium secondary batteries manufactured in Examples 1 to 5 and Comparative Examples 1 to 7 were observed using a scanning electron microscope (SEM), and the artificial graphite and natural graphite were distinguished from each other based on their particle shapes. The volume ratio of the artificial graphite and natural graphite was then measured, and the ratio of the weight of natural graphite to the total weight of natural graphite and artificial graphite was calculated and measured by multiplying the densities of the artificial graphite and natural graphite, respectively. The results are shown in Table 1 below. 3) S N measurement The negative electrodes of the lithium secondary batteries manufactured in the above Examples 1 to 5 and Comparative Examples 1 to 7 were scraped into powder form, and then the nitrogen gas adsorption amount of the powder at liquid nitrogen temperature (77 K) was measured using BELSORP-mino II of BEL Japan, thereby determining the BET specific surface area (unit: m) of the negative electrode active material included in the lithium secondary batteries manufactured in each of the Examples 1 to 5 and Comparative Examples 1 to 7. 2 / g) was measured. The results are shown in Table 1 below. 4) E measurement The lithium secondary batteries manufactured in Examples 1 to 5 and Comparative Examples 1 to 7 were each stored at 25°C for 24 hours, then charged to 4.2 V at 25°C and then discharged to 2.5 V three times during a charge-discharge cycle, thereby activating each lithium secondary battery. After this, the total weight of each activated lithium secondary battery was measured, and each lithium secondary battery was disassembled to measure the weight of the electrolyte in the lithium secondary batteries manufactured in Examples 1 to 5 and Comparative Examples 1 to 7. Specifically, the weight of the electrolyte was (1) the weight (M) of the activated lithium secondary battery before disassembling the activated lithium secondary battery. L ), (2) a step of disassembling the lithium secondary battery to remove the electrolyte present in the battery case, (3) a step of immersing the battery case and the electrode assembly in a dimethyl carbonate solvent to remove the electrolyte present in the surface of the battery case, the surface of the electrode assembly, and the internal pores, and then drying the battery case and the electrode assembly, (4) a step of measuring the weight (M) of the dried battery case. C ) and the weight (M) of the dried electrode assembly A ) After going through the step of measuring the measured M L , M C , M A It was measured by substituting it into Equation A. [Formula A] Weight of the above electrolyte = M L -M C -M A P S N G S N [m 2 / g]ETS index [g / m 2]Example 100.61.70.0980.00Example 20.50.51.50.1051.59Example 30.50.51.50.0981.70Example 40.20.51.50.1050.63Example 50.60.10.90.0980.68Comparative Example 10.80.31.20.1051.94Comparative Example 210.61.70.1053.44Comparative Example 30.80.51.50.1052.54Comparative Example 410.51.50.1053.18Comparative Example 50.50.51.50.0921.81Comparative Example 60.50.71.50.1052.22Comparative Example 70.40.92.10.0921.86 Experimental Example 2: Hot Box Test After activating the lithium secondary batteries of Examples 1 to 5 and Comparative Examples 1 to 7 manufactured above, the activated lithium secondary batteries of Examples 1 to 5 and Comparative Examples 1 to 7 were charged to 4.2 V, 0.05 C under CC / CV, 1 / 3 C conditions at 25°C to fully charge up to 100% SOC. Each fully charged lithium secondary battery was placed in a hot box chamber at room temperature, heated to 130°C at a heating rate of 5°C / min for 30 minutes, stored for 1 hour, and measured for the temperature change of the battery. If thermal runaway and ignition did not occur during the test, it was indicated as Pass, and if thermal runaway and / or ignition occurred, it was indicated as Fail. The results are shown in Table 2 below. Hot Box Test ResultsExample 1PassExample 2PassExample 3PassExample 4PassExample 5PassComparative Example 1FailComparative Example 2FailComparative Example 3FailComparative Example 4FailComparative Example 5FailComparative Example 6FailComparative Example 7Fail Referring to Table 2 above, it can be confirmed that the lithium secondary batteries manufactured in Examples 1 to 5 did not exhibit thermal runaway and / or ignition as a result of the hot box test, but the lithium secondary batteries manufactured in Comparative Examples 1 to 7 exhibited thermal runaway and / or ignition as a result of the hot box test. Through this, it can be understood that the lithium secondary batteries manufactured in Examples 1 to 5 have excellent thermal safety. (Explanation of symbols) 1: Lithium secondary battery 2: Pack Housing 3: Battery pack 10: Bipolar 11: Negative 12: Membrane 20: Whole house 21: Active material layer 21a: Negative active material layer 22: No-nonsense 22a: Cathode ignorance 22c: The ignorance of the polarity 24: Insulation layer C: Center of winding 140: Lithium secondary battery 141: Electrode assembly 142: Battery Case 143: Seal 143a: Cap plate 143b: 1st gasket 143c: Connecting plate 143d: protrusion 144: 1st Collection Plate 145: 2nd collection plate 146: Insulator 146a: Bipolar ignorance 146b: Negative polarity 147: Bidding Department 148: Crimping section 149: Lead 151: Lead Hall 152: Benting Department 170: Lithium secondary battery 171: Battery Case 172: Rivet terminal 172a: Terminal exposed part 172b: Terminal insertion part 173: 2nd gasket 173a: Gasket exposure area 173b: Gasket insert 174: Insulating cap 176: Second collector plate 178: Seal 178a: Cap plate 178b: 1st gasket 179: Vent 180: Bidding section 181: Crimping section

Claims

1. A lithium secondary battery comprising an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode; an electrolyte; and a battery case in which the electrode assembly and the electrolyte are accommodated. The above positive electrode comprises a lithium nickel-based oxide containing nickel at 80 mol% or more among all metals excluding lithium as a positive electrode active material, The above lithium nickel-based oxide comprises single particles, secondary particles or a combination thereof, The above negative electrode comprises at least one selected from the group consisting of natural graphite and artificial graphite as a negative electrode active material, TS index (unit: g / m) defined by Equation 1 below 2 ) is 1.72 or less, lithium secondary battery. [Formula 1] In the above equation 1, P S means the ratio of the weight of the lithium nickel oxide in the form of secondary particles to the total weight of the lithium nickel oxide, N G means the ratio of the weight of natural graphite to the total weight of the above natural graphite and artificial graphite, S N is the BET surface area of ​​the above negative active material (unit: m 2 / g) means, E refers to the ratio of the total weight of the electrolyte to the total weight of the lithium secondary battery.

2. In paragraph 1, Above P S A lithium secondary battery having an I of 0.7 or less.

3. In paragraph 1, Above N G A lithium secondary battery having an R of 0.6 or less.

4. In paragraph 1, S above N Silver 1.3m 2 / g to 1.9m 2 / g, lithium secondary battery.

5. In paragraph 1, A lithium secondary battery, wherein E is 0.08 to 0.

13.

6. In paragraph 1, A lithium secondary battery, wherein the lithium nickel-based oxide is represented by the following chemical formula 1. [Chemical Formula 1] Li a1 [Ni x1 Co y1 Mr z1 M 1 w1 ]O2 In the above chemical formula 1, M 1 is at least one doping element selected from the group consisting of W, Cu, Fe, V, Cr, Ti, Zr, Zn, Al, In, Ta, Y, In, La, Sr, Ga, Sc, Gd, Sm, Ca, Ce, Nb, Mg, B, and Mo, and 0.8≤a1≤1.2, 0.8≤x1<1, 0 <y1≤0.2, 0<z1≤0.2, 0≤w1≤0.1이다.

7. In paragraph 1, The above battery case is a cylindrical battery case, a lithium secondary battery.

8. In paragraph 1, The above lithium secondary battery is a lithium secondary battery, wherein the ratio of diameter (R) to height (H) (R / H) is 0.4 or more.

9. In paragraph 1, The above lithium secondary battery is a 46110 cell, a 48110 cell, a 4880 cell or a 4680 cell, a lithium secondary battery.

10. In paragraph 1, A lithium secondary battery, wherein the lithium secondary battery includes a non-conductive portion on which an active material layer is not formed on at least a portion of the positive electrode and the negative electrode, and the non-conductive portion of the positive electrode and the non-conductive portion of the negative electrode are defined as electrode tabs.

11. In paragraph 10, A lithium secondary battery, wherein the positive electrode uncoated portion and the negative electrode uncoated portion are formed along the direction in which the electrode assembly is wound on one end of each of the positive and negative electrodes, and a current collecting plate is coupled to each of the positive electrode uncoated portion and the negative electrode uncoated portion, and the current collecting plate is connected to an electrode terminal.

12. In paragraph 10, The above positive and negative electrode parts are processed into a plurality of independently foldable segments, A lithium secondary battery, wherein at least some of the plurality of segments are bent toward the winding center of the electrode assembly.

13. In paragraph 12, A lithium secondary battery, wherein at least some of the plurality of folded segments overlap on the upper and lower sides of the electrode assembly, and the current collecting plate is bonded to the plurality of overlapped segments.

14. A battery pack comprising a lithium secondary battery according to any one of claims 1 to 13 as a unit cell.

Images