Specification Title of Invention: Method for predicting lifespan characteristics of secondary batteries having a carbon-based hybrid anode technical field [One] The present invention relates to a method for predicting the lifespan characteristics of a secondary battery having a carbon-based hybrid anode. [2] This application claims priority based on Korean Application No. 10-2019-0139765 filed on November 4, 2019, and all contents disclosed in the specification of the application are incorporated herein by reference. background [3] In recent years, the market for electric vehicles, robots, and power storage devices has rapidly developed, requiring secondary batteries with high energy density, stability, miniaturization, weight reduction, and long lifespan. Whether it is applied to such a large-scale field depends on securing the performance of the secondary battery with a higher energy density per weight or volume than the current level of energy density. [4] Graphite, which is currently commercialized as an anode active material for lithium-ion batteries, has a theoretical capacity of 372 mAh/g (about 160Wh/kg). Silicon (Si), which has a capacity (4200 mAh/g) more than 10 times that of graphite, is attracting attention as a negative electrode material for a next-generation non-aqueous electrolyte secondary battery. In addition, as a new material to replace carbon-based materials such as graphite, it has been proposed to use various non-carbon-based materials as negative electrode active materials in addition to silicon alloying with lithium and exhibiting high theoretical capacity. [5] However, due to the high volume expansion rate of the silicon-based material in the process of alloying with lithium, cracks in the inside and the surface of the electrode are generated, the active material is dropped, and the cycle capacity of the secondary battery may rapidly deteriorate due to deterioration of electrical contact. In order to solve the problems of the silicon-based material, attempts are actively being made to apply a hybrid negative electrode in which a non-carbon-based material such as a silicon-based material and a carbon-based material are mixed. [6] Despite these attempts, there is still a limit to improving the life characteristics by simply mixing and using a non-carbon-based material and a carbon-based material. Therefore, there is still a need for designing an optimal anode by predicting lifespan characteristics in a secondary battery having a hybrid anode. DETAILED DESCRIPTION OF THE INVENTION technical challenge [7] An object of the present invention is to provide a method for predicting the lifespan characteristics of a secondary battery having a carbon-based hybrid anode. [8] Other objects and advantages of the present invention will be understood by the following description. On the other hand, it will be easily understood that the objects and advantages of the present invention can be realized by means or methods described in the claims, and combinations thereof. means of solving the problem [9] In order to solve the problems of the present invention, according to an aspect of the present invention there is provided a method for predicting the lifespan characteristics of the carbon-based hybrid negative electrode of the following embodiment. [10] According to a first embodiment, [11] As a method for predicting the lifespan characteristics of a secondary battery having a carbon-based hybrid negative electrode, [12] In the method, during charging and discharging of a target secondary battery having a target carbon-based hybrid negative electrode comprising a carbon-based negative electrode active material and a non-carbon-based negative electrode active material, the lattice spacing (d) of the carbon-based negative electrode active material of the target carbon-based hybrid negative electrode -spacing) is measured using an X-ray diffractometer, and plotting the change in the lattice spacing value versus the charge/discharge capacity (X-axis) as a graph; [13] calculating a target slope difference, which is a difference between slope values ​​that are changed with an inflection point of the graph as a boundary during discharge in the plotted graph; [14] comparing the target gradient difference with a reference gradient difference, which is a difference in gradient values ​​with an inflection point as a boundary in a graph showing a change in a grid interval value versus a charge/discharge capacity (X-axis) of a reference secondary battery; and [15] Predicting whether or not the lifespan characteristics of the target secondary battery are improved from the comparison result compared to the reference secondary battery; is provided. [16] In the second embodiment, according to the first embodiment, [17] The reference slope difference is, [18] During charging and discharging of a reference secondary battery having a reference carbon-based hybrid negative electrode including a carbon-based negative active material and a non-carbon-based negative active material, the lattice spacing (d-spacing) of the carbon-based negative active material of the reference carbon-based hybrid negative electrode Measuring using an X-ray diffractometer (X-ray diffractometer), plotting the change in the value of the grid spacing versus the charge/discharge capacity (X-axis) as a graph; and [19] In the plotted graph, calculating a target slope difference, which is a difference between slope values ​​changed with the inflection point of the graph as a boundary while the discharge is in progress; [20] According to the third embodiment, according to the first embodiment or the second embodiment, [21] In the plotted graph, during discharge, the discharge capacity after the inflection point of the graph corresponds to the portion of the capacity contributed by the non-carbon-based negative active material, and the discharge capacity before the inflection point may correspond to the portion of the capacity contributed by the carbon-based negative active material. . [22] According to the fourth embodiment, according to any one of the first to third embodiments, [23] The target gradient difference and the reference gradient difference may be calculated by the following equation. [24] Absolute value of target slope difference = [(slope of graph before inflection point in graph of target secondary battery)-(slope of graph after inflection point in graph of target secondary battery)] [25] Reference slope difference = absolute value of [(slope of graph before inflection point in graph of reference secondary battery)-(slope of graph after inflection point in graph of reference secondary battery)] [26] According to the fifth embodiment, according to any one of the first to fourth embodiments, [27] From the comparison result, when the target slope difference is greater than the reference slope difference, it may be determined that the lifespan characteristics of the target secondary battery are improved compared to the reference secondary battery. [28] According to the sixth embodiment, according to any one of the first to fifth embodiments, [29] From the comparison result, when the target slope difference is smaller than the reference slope difference, it may be determined that the lifespan characteristics of the target secondary battery are deteriorated compared to the reference secondary battery. [30] According to the seventh embodiment, according to any one of the first to sixth embodiments, [31] The carbon-based negative active material may include natural graphite, artificial graphite, soft carbon, hard carbon, pitch carbide, calcined coke, graphene, carbon nanotubes, or two or more of these. [32] According to the eighth embodiment, according to any one of the first to seventh embodiments, [33] The non-carbon-based negative active material may include a metal or a metalloid capable of alloying with lithium. [34] According to the ninth embodiment, according to any one of the first to eighth embodiments, [35] The non-carbon-based negative active material is a metal or metalloid selected from the group consisting of Si, Sn, In, Pb, Ga, Ge, Al, Bi, Sb, Ag, Mg, Zn, Pt, Ti, and combinations thereof, an oxide thereof, The carbon complex, the carbon complex of the metal or metalloid oxide, or a mixture thereof may be included. [36] According to the tenth embodiment, according to any one of the first to ninth embodiments, [37] The non-carbon-based negative active material may include Si, SiO x (0 [95] A mixed negative electrode active material of SiO (silicon oxide) with a Coulombic efficiency of 80% or more when charged and discharged with artificial graphite as a carbon-based active material and 0.1C, a non-carbon-based active material, a binder polymer (SBR (styrene-butadiene rubber) and CMC (carboxymethyl cellulose)), a mixture of carbon black as a conductive material in a weight ratio of 95:3.5:1.5, and water as a dispersion medium were mixed in a weight ratio of 1:2 to prepare a slurry for the active material layer. At this time, the weight of SiO was 5 wt% based on the total weight of the mixed negative active material of the artificial graphite and SiO, and the weight ratio of SBR (styrene-butadiene rubber) and CMC (carboxymethyl cellulose) was 2.3:1.2. [96] Using a slot die, the slurry for the active material layer was coated on one surface of a copper (Cu) thin film, which is a negative current collector, having a thickness of 10 μm, and dried at 130° C. under vacuum for 1 hour to form an active material layer on the copper thin film. . [97] The active material layer thus formed was rolled by a roll pressing method to prepare a negative electrode having a single-layered active material layer having a thickness of 80 μm. Based on the dry weight of the anode active material layer, the loading amount was 17 mg/cm 2 . [98] [99] Li(Ni 0.8 Mn 0.1 Co 0.1 )O 2 (NCM-811) as a cathode active material, carbon black as a conductive material, and polyvinylidene fluoride (PVdF) as a binder in a weight ratio of 96:2:2 as a solvent Phosphorus was added to N-methylpyrrolidone (NMP) to prepare a cathode active material slurry. The slurry was coated on one surface of an aluminum current collector having a thickness of 15 μm, and drying and rolling were performed under the same conditions as the negative electrode to prepare a positive electrode. At this time, the loading amount based on the dry weight of the positive electrode active material layer was 20 mg/cm 2 . [100] [101] In an organic solvent mixed with ethylene carbonate (EC), propylene carbonate (PC) and ethylmethyl carbonate (EMC) in a composition of 3:1:6 (volume ratio), LiPF 6 was dissolved to a concentration of 1.0M to obtain a non-aqueous electrolyte solution. prepared. [102] After interposing the polyolefin separator between the positive electrode and the negative electrode prepared above, the electrolyte was injected to prepare a lithium secondary battery (Sample A, reference secondary battery). [103] [104] Preparation Example 2 - Sample B (target secondary battery) [105] [106] A mixture of artificial graphite as a carbon-based active material, a binder polymer (SBR (styrene-butadiene rubber) and CMC (carboxymethyl cellulose)), and carbon black as a conductive material in a weight ratio of 95:3.5:1.5, and water as a dispersion medium. A slurry for the first active material layer was prepared by mixing the weight ratio of the dispersion medium to 1:2. At this time, the weight ratio of SBR (styrene-butadiene rubber) and CMC (carboxymethyl cellulose) was 2.3:1.2. [107] Instead of artificial graphite, SiO (silicon oxide) having a Coulombic efficiency of 80% or more when charged and discharged with 0.1C, a non-carbon-based active material, is used, and the SiO content is 5% by weight based on the total weight of artificial graphite and SiO A slurry for the second active material layer was prepared in the same manner as the slurry for the first active material layer, except that [108] Using a double slot die, the slurry for the first active material layer is coated on one surface of a copper (Cu) thin film that is a negative current collector having a thickness of 10 μm, and then the slurry for the second active material layer is applied on the slurry for the first active material layer. Coating, and drying for 1 hour under vacuum at 130 ℃, to form a first active material layer and a second active material layer on the copper thin film. [109] The first active material layer and the second active material layer thus formed were simultaneously rolled by a roll pressing method to prepare an anode having a double-layered active material layer having a thickness of 80 μm. Based on the dry weight of the anode active material layer, the loading amount was 17 mg/cm 2 . [110] [111] A positive electrode was prepared in the same manner as in Preparation Example 1. [112] [113] A non-aqueous electrolyte was prepared in the same manner as in Preparation Example 1. [114] After interposing the polyolefin separator between the positive electrode and the negative electrode prepared above, the electrolyte was injected to prepare a lithium secondary battery (Sample B, target secondary battery). [115] [116] Experimental example [117] Experimental Example 1 [118] Using a transmission x-ray diffractometer (manufacturer: Bruker, product name: D8 Advance), the secondary batteries of Preparation Examples 1 and 2 were subjected to the same conditions as the cycle test: 0.33 CC/CV charge, 0.33 CC discharge. While charging and discharging under the conditions, the (002) lattice interface peak (2θ = 7.5 ~ 11 (Ag λ = 0.56)) of the artificial graphite contained in the negative electrode of each secondary battery was tracked and scanned. The (002) lattice peak of the artificial graphite contained in the negative electrodes of Preparation Examples 1 to 3 obtained by scanning in this way was fitted based on Bragg's Law to determine the lattice d-spacing of the artificial graphite. Calculated. [119] 1A and 1B show a grid of artificial graphite included in each negative electrode according to the change in capacity during charging and discharging with respect to Sample A (reference secondary battery) of Preparation Example 1 and Sample B (target secondary battery) of Preparation Example 2 It is a graph showing the result of observation of each change in interval in real time. [120] Referring to FIGS. 1A and 1B , when the sample A (reference secondary battery) and sample B (target secondary battery) are discharged, both in the graph curve, the discharge capacity is about 30 mAh, the inflection point at which the slope of the curve rapidly changes as a boundary. occurs In the portion where the capacity is greater than the capacity at the inflection point (the early discharge portion), the change in the graphite lattice is very large according to the change in capacity, and the discharge capacity at this time is due to lithium ions desorbed from the graphite. [121] In the case of the reference secondary battery of Preparation Example 1 of FIG. 1A, the decrease in the lattice spacing in the second half of the discharge with respect to the inflection point was smaller than that in the first half, but the slope did not change as rapidly as that of the target secondary battery shown in FIG. 1B. That is, it can be seen that the target gradient difference is larger than the reference gradient difference. [122] In the case of FIG. 1B, the capacity was changed even though there was no change in the graphite lattice spacing or very small in the portion where the capacity was smaller than the capacity at the inflection point (the second half of the discharge), that is, in the range of about 30 to 0 mAh of the discharge capacity. In the latter half of this discharge, lithium ions are not desorbed from graphite, but lithium ions inserted into SiO are desorbed. [123] Specifically, in the case of the reference secondary battery (Sample A) of Preparation Example 1 having a hybrid negative electrode having a single layer structure in which a carbon-based negative electrode active material and a non-carbon-based negative electrode active material are uniformly mixed as shown in FIG. The gradient of change showed a sharp decrease in section ②, and then showed a smaller slope than the slope of section ② when entering section ①, and lithium ions were desorbed at a constant rate. [124] On the other hand, in the target secondary battery (Sample B) of Preparation Example 1 having a hybrid anode having a two-layer structure in which the carbon-based anode active material layer and the non-carbon-based anode active material layer are completely separated as shown in FIG. reaction) was observed. In section ② of FIG. 1b, all lithium ions remaining in the carbon-based anode active material, which is artificial graphite, are desorbed and escape, and in section ①, lithium ions are desorbed only from the non-carbon-based anode active material (eg, SiO). As described above, since the reaction is sequentially divided from section ② to section ①, this flat region can be called a “step reaction”. [125] Specifically, considering that the data measurement interval in FIG. 1b is 4 minutes per point, the lattice interval of artificial graphite does not change at all, despite the steady increase in the discharge capacity for about 20 to 25 minutes in section ① in the latter half of the discharge. , from this, in the hybrid negative electrode system of Sample B, it can be interpreted that the non-carbon-based negative active material other than the carbon-based negative active material, which is artificial graphite, preferentially causes lithium ion desorption. This can be expected to bring about relief of structural stress related to volume expansion of artificial graphite. [126] As a result, as described above, since it can be seen that the target inclination difference of the target secondary battery (Sample B) is larger than the reference inclination difference of the reference secondary battery (Sample A), the target secondary battery (Sample A) in which the stress of artificial graphite is relieved It can be predicted that B) has better lifespan characteristics than the reference secondary battery (Sample A). [127] [128] Experimental Example 2 [129] In order to check whether the lifespan characteristics predicted in Experimental Example 1 match the actual results, the reference secondary battery of Preparation Example 1 (Sample A) and the target secondary battery of Preparation Example 2 (Sample B) were subjected to the same conditions as the cycle test of 0.33 The lifespan characteristics were tested by performing 200 charge/discharge cycles under CC/CV charging and 0.33 CC discharging conditions. [130] 2 is a graph showing the results of life characteristics of Sample A (reference secondary battery) of Preparation Example 1 and Sample B (target secondary battery) of Preparation Example 2; [131] Referring to FIG. 2 , compared to the reference secondary battery (Sample A) in which no flat section was observed in Experimental Example 1, the target secondary battery (Sample B) having a negative electrode exhibiting a flat section for about 20 to 25 minutes had a discharge capacity retention rate. It can be seen that it is much superior in terms of the life characteristics of this initial 200 cycles. Claims [Claim 1] A method for predicting the lifespan characteristics of a secondary battery having a carbon-based hybrid negative electrode, wherein the method includes a carbon-based negative active material and a non-carbon-based negative active material during charging and discharging of a target secondary battery having a target carbon-based hybrid negative electrode comprising: The lattice spacing (d-spacing) of the carbon-based negative active material of the target carbon-based hybrid negative electrode was measured using an X-ray diffractometer, and the lattice spacing value compared to the charge/discharge capacity (X-axis) plotting the change as a graph; calculating a target slope difference, which is a difference between slope values ​​that are changed with an inflection point of the graph as a boundary during discharge in the plotted graph; comparing the target gradient difference with a reference gradient difference, which is a difference in gradient values ​​with an inflection point as a boundary in a graph showing a change in a grid interval value versus a charge/discharge capacity (X-axis) of a reference secondary battery; and predicting whether or not the lifespan characteristics of the target secondary battery are improved from the comparison result compared to the reference secondary battery. [Claim 2] According to claim 1, wherein the reference slope difference is, during charging and discharging of a reference secondary battery having a reference carbon-based hybrid negative electrode including a carbon-based negative electrode active material and a non-carbon-based negative electrode active material, the carbon of the reference carbon-based hybrid negative electrode measuring the lattice spacing (d-spacing) of the anode active material using an X-ray diffractometer, and plotting the change in the lattice spacing value versus the charge/discharge capacity (X-axis) as a graph; and calculating a target gradient difference, which is a difference in gradient values ​​that are changed with the inflection point of the graph as a boundary during discharge in the plotted graph. [Claim 3] According to claim 1, wherein in the plotted graph, the discharge capacity after the inflection point of the graph during discharge corresponds to the portion of the capacity contributed by the non-carbon-based negative active material, and the discharge capacity before the inflection point is the capacity contributed by the carbon-based negative active material A method for predicting lifespan characteristics of a secondary battery, characterized in that it corresponds to the part. [Claim 4] The method of claim 1, wherein the difference between the target gradient and the reference gradient is calculated by the following equation. Target slope difference = [(the slope of the graph before the inflection point in the graph of the target secondary battery)-(the slope of the graph after the inflection point in the graph of the target secondary battery)] Reference slope difference = [(in the graph of the reference secondary battery) Absolute value of [the slope of the graph before the inflection point)-(the slope of the graph after the inflection point in the graph of the reference secondary battery)] [Claim 5] The lifespan of the secondary battery according to claim 1, wherein, from the comparison result, when the difference in the target inclination is greater than the difference in the reference inclination, it is determined that the lifespan characteristics of the target secondary battery are improved compared to the reference secondary battery. A method of predicting characteristics. [Claim 6] The lifespan of the secondary battery according to claim 1, wherein, from the comparison result, when the difference in the target inclination is smaller than the difference in the reference inclination, it is determined that the lifespan characteristics of the target secondary battery are deteriorated compared to the reference secondary battery. A method of predicting characteristics. [Claim 7] The method of claim 1, wherein the carbon-based negative active material comprises natural graphite, artificial graphite, soft carbon, hard carbon, pitch carbide, calcined coke, graphene, carbon nanotube, or two or more thereof. A method for predicting the lifespan characteristics of secondary batteries. [Claim 8] The method of claim 1, wherein the non-carbon-based negative active material includes a metal or a metalloid capable of alloying with lithium. [Claim 9] According to claim 1, wherein the non-carbon-based negative active material is a metal selected from the group consisting of Si, Sn, In, Pb, Ga, Ge, Al, Bi, Sb, Ag, Mg, Zn, Pt, Ti, and combinations thereof; A method for predicting lifespan characteristics of a secondary battery, comprising a metalloid, an oxide thereof, a carbon composite thereof, a carbon composite of the metal or metalloid oxide, or a mixture thereof. [Claim 10] The method of claim 1, wherein the non-carbon-based negative active material comprises Si, SiO x (0