Method for preparing positive electrode active material

Abstract

A method for manufacturing a positive electrode active material is provided, comprising the step of calcining a positive electrode active material precursor, wherein the calcination step is performed in a calcination furnace, and the calcination step includes a high-pressure adjustment process in which high-pressure gas is supplied into the calcination furnace, wherein the gas supply amount per hour of the high-pressure adjustment process is 8 m³ to 20 m³ per unit volume (m³) of the high-pressure adjustment section in the calcination furnace, and the gas supply amount is calculated based on 25°C and 1 atm, thereby improving the uniformity of quality and the content of lithium by-products in the active material. Through the manufacture of such a positive electrode active material, the productivity of the positive electrode active material can be improved, stability can be improved due to excellent uniformity of quality, and performance with improved lifespan and capacity characteristics can be achieved due to enhanced energy density.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a positive electrode active material. Specifically, it relates to a method for manufacturing a positive electrode active material in which the amount of gas supplied during calcination is controlled. More specifically, the method comprises a step of calcining a positive electrode active material precursor, wherein the calcination step is performed in a calcination furnace, and wherein the calcination step includes a high-pressure adjustment process in which high-pressure gas is supplied into the calcination furnace, and wherein the amount of gas supplied per hour in the high-pressure adjustment process is the unit volume (m³) of the high-pressure adjustment section within the calcination furnace. 3 8 m per ) 3 to 20 m 3 The present invention relates to a method for manufacturing a positive electrode active material, wherein the above gas supply amount is calculated based on 25℃ and 1 atm. Background Technology

[0002] With the increasing technological development and demand for mobile devices, the demand for rechargeable batteries as an energy source is rapidly rising. Among these rechargeable batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used.

[0003] Cathode active materials are generally manufactured by mixing lithium-containing raw materials with transition metal hydroxides and then calcining them. Conventionally, this process was carried out using a batch-type calcination method, in which the calcination is performed separately for each manufacturing process of the cathode active material. However, while this batch-type calcination method offers the advantage of producing active materials of uniform quality, it presents problems such as difficulty in improving productivity and poor economic efficiency because each cathode active material requires a separate calcination process. In particular, with the commercialization of lithium-ion batteries requiring large quantities of cathode active materials, there is a demand for manufacturing methods that can increase the productivity of cathode active materials, in addition to the aforementioned batch-type calcination method.

[0004] Accordingly, continuous calcination is attracting attention as it enables the continuous manufacturing of cathode active materials by allowing the continuous input and output of calcination materials within a single kiln, in contrast to batch-type calcination, where the calcination process is performed separately for each cathode active material. This continuous calcination has the advantage of superior productivity and economic efficiency compared to batch-type calcination, as it allows for the continuous input of calcination materials even after they have been initially introduced, as long as the kiln's internal capacity is not exceeded, thereby enabling the continuous production of cathode active materials.

[0005] However, in the case of the above continuous firing process, the firing material is fed into the entire firing furnace during the middle stage of firing, but since there is empty space in the latter or earlier part of the firing furnace during the beginning or end stage of firing, even if the same amount of gas is supplied throughout the entire firing process, the gas retention space inside the firing furnace varies depending on the beginning, middle, and end stages of firing. In addition, gas is generated from the firing material itself due to reactions such as lithium and transition metals within the firing material during firing, and since the amount of firing material present in the firing furnace varies depending on the firing time, changes occur not only in the gas retention space inside the firing furnace but also in the composition and pressure of the gas constituting the inside of the firing furnace.

[0006] In the case of the calcination process for manufacturing positive electrode active materials, a mixture of lithium-containing raw materials and transition metal hydroxides is generally introduced, and as the mixture undergoes calcination, growth of the particles and interactions between the internal metals are formed. These reactions are influenced not only by the calcination temperature but also by the type of gas supplied during calcination and the pressure of the gas.

[0007] In other words, while continuous firing offers the advantage of superior productivity and economic efficiency compared to batch firing, the nature of the continuous process causes changes in the gas retention space, gas composition, and gas pressure within the furnace depending on the firing time; these changes also affect the quality of the cathode active material. Consequently, the quality of cathode active materials fired during the initial and final stages of continuous firing differs from that fired during the middle stage. To mitigate this quality difference, a post-processing step is sometimes performed to separate the materials fired during the initial and final stages and ensure they achieve a quality similar to that of the materials fired during the middle stage.

[0008] Ultimately, although continuous firing has improved productivity compared to batch-type firing, there is still a problem in that it is difficult to achieve productivity that meets demand because quality differences between cathode active materials occur depending on the firing time, necessitating post-processing.

[0009] Accordingly, there is a need for a method to manufacture cathode active materials with improved productivity by enabling continuous calcination of the cathode active materials while suppressing quality differences between cathode active materials depending on the production time. Prior art literature

[0010] Korean Patent Publication No. 10-2018-0015629 The problem to be solved

[0011] The object of the present invention is to include a step of calcining an anode active material precursor, wherein the calcination step is performed in a calcination furnace, and wherein the calcination step includes a high-pressure adjustment process in which a high-pressure gas is supplied into the calcination furnace, and wherein the gas supply amount per hour of the high-pressure adjustment process is a unit volume (m²) of the high-pressure adjustment section in the calcination furnace. 3 8 m per ) 3 to 20 m3 The present invention provides a method for manufacturing a cathode active material that improves quality by suppressing the generation of lithium by-products and simultaneously improves the quality difference between cathode active materials that occurs depending on the manufacturing time, wherein the above gas supply amount is calculated based on 25℃ and 1 atm. means of solving the problem

[0012] A first aspect of the present invention comprises a step of calcining an anode active material precursor, wherein the calcination step is performed in a calcination furnace, and wherein the calcination step comprises a high-pressure adjustment process in which a high-pressure gas is supplied into the calcination furnace, and wherein the gas supply amount per hour of the high-pressure adjustment process is a unit volume (m²) of the high-pressure adjustment section in the calcination furnace. 3 8 m per ) 3 to 20 m 3 The present invention provides a method for manufacturing a positive electrode active material, wherein the above gas supply amount is calculated based on 25℃ and 1 atm.

[0013] In one embodiment of the present invention, the high pressure adjustment process is performed under an atmosphere in which the purity of oxygen is 80% to 99%.

[0014] In one embodiment of the present invention, the total time required for the high pressure adjustment process is 6 to 14 hours.

[0015] In one embodiment of the present invention, the temperature of the high pressure adjustment process is 600°C to 1000°C.

[0016] In one embodiment of the present invention, the firing step includes a heating step, a holding step, and a cooling step, and the high pressure adjustment process is performed in the holding step.

[0017] In one embodiment of the present invention, the firing step is performed as a continuous process.

[0018] In one embodiment of the present invention, the firing step is performed using a roller hearth kiln (RHK) firing method, which is a continuous firing method.

[0019] In one embodiment of the present invention, the supply amount of the anode active material precursor per hour in the calcination furnace is 100 kg to 2000 kg.

[0020] In one embodiment of the present invention, the total volume of the high-pressure adjustment section is 30 m 3 to 300 m 3 am.

[0021] In one embodiment of the present invention, the total length of the high-pressure adjustment section is 10 m to 200 m.

[0022] In one embodiment of the present invention, the kiln comprises a plurality of firing sections, and the number of firing sections where the high-pressure adjustment process is performed is 10 to 50.

[0023] In one embodiment of the present invention, the positive electrode active material comprises a lithium transition metal oxide, and the lithium transition metal oxide comprises 0.1% to 1.5% by weight of a lithium byproduct based on the total weight of the lithium transition metal oxide.

[0024] In one embodiment of the present invention, the positive electrode active material comprises a lithium transition metal oxide, and the lithium transition metal oxide particles are composed of one or more primary particles, and the average particle size of the primary particles within the lithium transition metal oxide particles is 50 nm to 200 nm. Effects of the invention

[0025] A method for manufacturing a positive electrode active material according to the present invention comprises a step of calcining a positive electrode active material precursor, wherein the calcination step is performed in a calcination furnace, and wherein the calcination step includes a high-pressure adjustment process in which a high-pressure gas is supplied into the calcination furnace, and wherein the gas supply amount per hour of the high-pressure adjustment process is a unit volume (m²) of the high-pressure adjustment section in the calcination furnace. 3 8 m per ) 3 to 20 m 3The above gas supply amount is calculated based on 25℃ and 1 atm, and the cathode active material produced therefrom exhibits excellent quality with a low lithium byproduct content, while also having characteristics of equivalent quality between active materials produced at different times.

[0026] When applied to batteries, these characteristics can improve battery performance, such as capacity and lifespan, by enhancing energy density, and stability can also be improved due to excellent quality uniformity.

[0027] In addition, when the above manufacturing method is applied to an actual process, it is possible to produce cathode active materials of equivalent quality regardless of the time of manufacturing, which increases process productivity, facilitates application on a commercial scale, and can increase production efficiency. Brief explanation of the drawing

[0028] [Fig. 1] is a schematic diagram of a kiln according to one embodiment of the present invention. Specific details for implementing the invention

[0029] The present invention will be described in more detail below.

[0030] Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, the configurations described in the embodiments described in this specification are merely one preferred embodiment of the invention and do not represent all of the technical spirit of the invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0031] In this specification, when a part is described as "including" or "equipped" with a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include or be equipped with additional components.

[0032] In this specification, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0033] Where measurement conditions and methods are not specifically described for the physical properties described in this specification, said physical properties are measured according to measurement conditions and methods generally used by a person skilled in the art.

[0035] The present invention will be described in detail below.

[0037] Method for manufacturing positive electrode active material

[0038] The present invention provides a method for manufacturing a positive electrode active material.

[0039] As the demand for cathode active materials increased, a continuous process involving continuous calcination was conventionally used to increase productivity. However, in such a continuous process, the amount of active material present in the kiln varied during the initial, middle, and final stages of production. Consequently, changes in the volume of gas within the kiln occurred, leading to a problem where the quality of the active material varied depending on the production stage.

[0040] Accordingly, the present invention provides a method for manufacturing an anode active material of excellent quality while enabling the production of an active material of uniform quality by supplying gas at a specific pressure during a certain section of the calcination process to solve the above-mentioned problems, thereby minimizing quality differences depending on the production time.

[0041] In one embodiment of the present invention, the method for manufacturing the positive electrode active material comprises a step of calcining a positive electrode active material precursor, wherein the calcination step is performed in a calcination furnace, and wherein the calcination step comprises a high-pressure adjustment process in which a high-pressure gas is supplied into the calcination furnace, and the amount of gas supplied per hour in the high-pressure adjustment process is a unit volume (m²) of the high-pressure adjustment section in the calcination furnace. 3 8 m per ) 3 to 20 m 3 The above gas supply amount is calculated based on 25℃ and 1 atm.

[0042] Below, each component of the above-mentioned method for manufacturing the positive electrode active material will be described in detail.

[0044] kiln

[0045] In one embodiment of the present invention, the calcination step is performed in a calcination furnace. The calcination furnace to be used for the calcination may have a conventional structure known in the art as a structure for a calcination furnace for manufacturing a positive electrode active material, and is not particularly limited as long as it allows for the control of temperature and gas supply amount and enables the manufacturing of a positive electrode active material.

[0046] [Fig. 1] is a schematic diagram of a kiln (100) according to one embodiment of the present invention.

[0047] In one embodiment of the present invention, the kiln (100) is provided with an opening / closing part (10) and a firing part (20).

[0048] The above-mentioned firing section (20) is a part where firing of the firing material contained within the firing container (200) takes place. The above-mentioned firing section (20) may have a conventional structure known in the relevant technical field to be capable of supplying a uniform temperature and gas to the firing material within it.

[0049] The above-mentioned kiln (100) may be equipped with a plurality of firing sections (20) depending on the purpose of firing.

[0050] In one embodiment of the present invention, the firing section (20) comprises a moving section (30), a heating section (40), and a supply section (50).

[0051] The above moving part (30) is for moving the firing vessel (200) within the firing part (20). For the movement, it may include a roller (300), but is not limited to this and may be used as long as it is a method commonly used in the relevant technical field to move the firing vessel (200) in a specific direction. The movement may be performed by hardware, software, or a combination thereof.

[0052] When the above-mentioned kiln (100) is equipped with a plurality of firing sections (20), each firing section is equipped with a respective moving section (30), and the moving speed of the firing container (200) by each moving section (30) may be the same, or the moving speed between each firing section (20) may be different depending on the purpose of firing.

[0053] The heating unit (40) is intended to provide specific temperature conditions to the firing material introduced into the firing unit (20), and is a part that supplies heat to heat or cool the internal space of the firing unit (20) to a specific temperature. A conventional method known in the relevant technical field to be able to supply uniform heat to the inside of the firing unit (20) may be used.

[0054] When the above-mentioned kiln (100) is equipped with a plurality of firing sections (20), each firing section is equipped with a heating section (40), and the heat supply conditions inside the firing section (20) by each heating section (40) may be the same, and the temperature conditions, i.e., the heat supply conditions, between each firing section (20) may be different depending on the purpose of firing.

[0055] The above supply unit (50) is intended to provide specific gas supply conditions to the internal space of the firing unit (20) and is a part that controls the type and amount of gas supplied to the inside of the firing unit (20). A conventional method known in the relevant technical field to smoothly supply gas to the inside of the firing unit (2) may be used.

[0056] When the above-mentioned kiln (100) is equipped with a plurality of firing sections (20), each firing section is equipped with a respective supply section (50), and the gas supply conditions inside the firing section (20) by each supply section (50) may be the same, and the gas supply conditions, such as the type of gas supplied and the amount of gas supplied between each firing section (20), may be different depending on the purpose of firing.

[0057] The above-mentioned firing vessel (200) is for introducing a firing material into the firing furnace (100). A conventional vessel known in the relevant technical field as a vessel for stably holding a firing material may be used, and a container may be used, but is not limited thereto.

[0058] The above-mentioned firing container (200) can be inserted and moved within the firing furnace (100) in a stacked state, and may further include additional structures such as a cover for the stacking.

[0059] The above opening / closing part (10) is a part installed to allow the firing furnace (100) to be opened and closed for the firing section (20) of the firing vessel (200) to be inserted into and moved within the firing furnace (100). When the firing furnace (100) is equipped with a plurality of firing sections (20), each firing section (20) is spatially separated. The opening and closing of the above opening / closing part (10) is not restricted in its direction or shape as long as it can form a space sufficient for the firing vessel (200) to move between the outside, the firing section (20), and each firing section (20). Furthermore, the method of opening and closing can be performed without restrictions such as manual or automatic, as long as smooth movement of the firing vessel (200) is possible, and can be performed by hardware, software, or a combination thereof.

[0060] The above-mentioned kiln (100) basically has an opening / closing part (10) for introducing a firing vessel (200) from the outside and an opening / closing part (10) for discharging a firing vessel (200) to the outside. In the case where a plurality of firing sections (20) are provided, in addition to the opening / closing part (10) for introducing and discharging the firing vessel (200), an opening / closing part (10) for moving the firing vessel (200) between each firing section (20) is further provided.

[0061] In one embodiment of the present invention, the calcination furnace (100) is a continuous calcination furnace. Specifically, the calcination furnace (100) is a roller hearth kiln (RHK) type continuous calcination furnace. Since the continuous calcination furnace allows for the continuous supply of calcination materials and the acquisition of anode active materials during the calcination process, it is advantageous in terms of productivity compared to batch-type calcination, where a separate manufacturing process is performed for each active material required for production.

[0063] positive electrode active material precursor

[0064] In one embodiment of the present invention, the method for manufacturing the positive electrode active material includes the step of calcining the positive electrode active material precursor.

[0065] The above-mentioned positive electrode active material precursor refers to a material containing the said element as a raw material such as lithium or transition metal constituting the positive electrode active material precursor, and may be a mixture of lithium raw materials, transition metal raw materials, etc., or a lithium transition metal oxide, but is not limited thereto as long as it is commonly used in the relevant technical field for the manufacture of positive electrode active materials.

[0066] In one embodiment of the present invention, the positive electrode active material precursor comprises a lithium raw material and a transition metal raw material.

[0067] The above lithium raw material may be a lithium-containing sulfate, nitrate, acetate, carbonate, oxalate, citrate, halide, hydroxide, or oxyhydroxide, and for example, Li2CO3, LiNO3, LiNO2, LiOH, LiOH·H2O, LiH, LiF, LiCl, LiBr, LiI, CH3COOLi, Li2O, Li2SO4, CH3COOLi, Li3C6H5O7, or a mixture thereof may be used, and one of these alone or a mixture of two or more may be used. Specifically, it may be Li2CO3 or LiOH·H2O, but is not limited thereto as long as it is commonly used in the relevant technical field for the manufacture of cathode active materials.

[0068] In one embodiment of the present invention, the lithium raw material is LiOH·H2O.

[0069] By using LiOH·H2O as the above lithium raw material, the generation of impurities during the process can be suppressed, the cathode active material produced therefrom can possess stability at high pressure, and it is possible to manufacture a battery containing the above cathode active material with excellent characteristics such as capacity and energy density.

[0070] The above transition metal raw material may be an acetate, nitrate, sulfate, halide, sulfide, hydroxide, oxide, or oxyhydroxide of each transition metal included in the above positive active material, and specifically may be a hydroxide or an oxide, but is not limited thereto as long as it is commonly used in the relevant technical field for manufacturing positive active materials.

[0071] In one embodiment of the present invention, the transition metal raw material comprises a nickel raw material.

[0072] In one embodiment of the present invention, the transition metal raw material comprises a nickel raw material and further comprises a transition metal raw material selected from the group consisting of cobalt, manganese, aluminum, and combinations thereof.

[0073] In one embodiment of the present invention, the transition metal raw material comprises nickel and cobalt raw materials and further comprises a transition metal raw material selected from the group consisting of manganese, aluminum, and combinations thereof.

[0074] In one embodiment of the present invention, the transition metal raw material includes nickel, cobalt, and manganese raw materials.

[0075] The above nickel raw materials may be Ni(OH)2, NiO, NiOOH, NiCO3·2Ni(OH)2·4H2O, NiC2O2·2H2O, Ni(NO3)2·6H2O, NiSO4, NiSO4·6H2O, nickel fatty acid salts, or nickel halides, and any one or more of these may be used, but are not limited thereto as long as they are commonly used in the relevant technical field.

[0076] The above cobalt raw material may be Co(OH)2, CoSO4, CoOOH, Co(OCOCH3)2ㆍ4H2O, Co(NO3)2ㆍ6H2O, or CoSO4ㆍ7H2O, etc., and any one or more of these may be used, but is not limited thereto as long as they are commonly used in the relevant technical field.

[0077] The above manganese raw materials may be manganese oxides such as Mn2O3, MnO2, and Mn3O4; manganese salts such as MnCO3, Mn(NO3)2, MnSO4, manganese acetate, manganese dicarboxylate, manganese citrate, and manganese fatty acid salts; oxyhydroxide, or manganese chloride, and any one or more of these may be used, but are not limited thereto as long as they are commonly used in the relevant technical field.

[0078] In one embodiment of the present invention, the transition metal raw material is represented by the following [Chemical Formula 2], [Chemical Formula 3], or a combination thereof.

[0079] [Chemical Formula 2]

[0080] Ni x Co y M z OOH

[0081] In the above chemical formula 2, M is selected from the group consisting of Mn, Al, and combinations thereof. Specifically, M may be Mn.

[0082] The above x is 0≤x≤1. Specifically, the above x may be 0≤x≤1, 0.4≤x≤0.99, or 0.6≤x≤0.9.

[0083] The above y is 0≤y≤1. Specifically, the above y may be 0≤y≤1, 0.01≤y≤0.3, or 0.01≤y≤0.1.

[0084] The above z is 0≤z≤1. Specifically, the above z may be 0≤z≤1, 0.01≤z≤0.4, or 0.05≤z≤0.2.

[0085] For the above x, y, and z, x+y+z=1.

[0086] [Chemical Formula 3]

[0087] Ni p Co q M' r (OH)2

[0088] In the above chemical formula 2, M' is selected from the group consisting of Mn, Al, and combinations thereof. Specifically, M' may be Mn.

[0089] The above p is 0≤p≤1. Specifically, the above p may be 0≤p≤1, 0.4≤p≤0.99, or 0.6≤p≤0.9.

[0090] The above q is 0≤q≤1. Specifically, the above q may be 0≤q≤1, 0.01≤q≤0.3, or 0.01≤q≤0.1.

[0091] The above r is 0≤z≤1. Specifically, the above r may be 0≤4≤1, 0.01≤4≤0.4, or 0.05≤4≤0.2.

[0092] For the above p, q and r, p+q+r=1.

[0093] The above-mentioned cathode active material precursor may additionally include doping raw materials or coating raw materials to improve characteristics such as electrical conductivity or increase stability depending on the purpose of manufacturing the cathode active material. The doping raw materials or coating raw materials may be raw materials containing elements selected from the group consisting of Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, F, P, S, Y, Al, Co, and combinations thereof, but are not limited thereto as long as they are commonly used in the relevant technical field for manufacturing cathode active materials.

[0095] Calcination of positive electrode active material precursor

[0096] Generally, when manufacturing positive electrode active materials, a calcination process is carried out after mixing the raw materials to facilitate the reaction between lithium and transition metals within the active material and the growth of active material particles.

[0097] As mentioned above, continuous calcination is performed in most cases to increase the productivity of cathode active materials. However, in such continuous calcination, the amount of calcination material present in the furnace varies during the initial, middle, and final stages of the process due to process characteristics, and consequently, the gas retention space and internal pressure within the furnace change. Furthermore, the amount of gas emitted by the calcination material during the calcination process also varies; therefore, if the calcination time of the material differs within the overall process, differences will occur in the quality of the cathode active material obtained through the calcination, particularly in particle size.

[0098] Since the particle size of the cathode active material is a variable related to the efficiency of the cathode active material manufacturing process, such as tap density, and is also a variable related to the performance of the battery containing the cathode active material, such as energy density or capacity characteristics, if such differences in quality occur, additional processes must be performed, such as separating the calcined product at the beginning or end of the calcination process and subjecting it to a separate post-processing step.

[0099] Accordingly, the present invention aims to prevent differences in quality depending on the production time by supplying gas at a specific pressure during a certain section of the firing process to minimize changes in the gas retention space or amount of gas inside the firing furnace depending on the production time.

[0100] In one embodiment of the present invention, the firing step includes a high-pressure adjustment process in which high-pressure gas is supplied into the firing furnace (100).

[0101] The above high pressure adjustment process refers to a process of supplying gas at a constant pressure so that the total amount of gas or pressure inside the calcination furnace (100) is not affected by the amount of calcination material being calcined inside the calcination furnace (100) or the amount of gas generated by the calcination material during calcination, without reducing the efficiency of the manufacturing process of the positive active material, such as the degree of growth of the positive active material precursor through calcination or the reaction between the transition metal and lithium within the precursor.

[0102] As described above, when the firing step includes a high-pressure adjustment process, the part where the high-pressure adjustment process is performed within the firing furnace (100) throughout the entire firing furnace where the firing step is performed, that is, the space where the high-pressure adjustment process is performed, is called the high-pressure adjustment section.

[0103] In one embodiment of the present invention, the gas supply amount per hour of the high-pressure adjustment process is the unit volume (m²) of the high-pressure adjustment section within the kiln. 3 8 m per ) 3 to 20 m 3 is. Specifically, the above-mentioned gas supply amount per hour is 8 m 3 That is all, 8.5 m 3 More than or 9 m 3 That is all, 20 m 3 Below, 19.5 m 3 Below, 19 m 3 Below, 18.5 m 3 Below, 18 m 3 Below, 17.5 m 3 Below, 17 m 3 Below, 16.5 m 3 Below, 16 m 3 Below, 15.5 m 3 Below, 15 m 3 Below, 14.5 m 3 Below, 14 m 3 Below, 13.5 m 3 Below, 13 m 3 Below, 12.5 m 3 Below, 12 m 3 Below, 11.5 m 3Below, 11 m 3 Below, 10.5 m 3 Below, 10 m 3 Less than or equal to 9.5 m 3 Less than, and 8 m 3 to 20 m 3 , 8 m 3 to 15 m 3 or 8 m 3 to 12 m 3 It could be.

[0104] The above gas supply amount is calculated based on 25℃ and 1 atm. This does not mean that the gas supply was carried out at 25℃ and 1 atm, but rather the above 8 m 3 to 20 m 3 The volume of gas indicated by means the volume of gas calculated at 25℃ and 1 atm.

[0105] When the supply amount of the gas in this high-pressure adjustment process satisfies the above range, the amount of gas inside the kiln can be kept constant while maintaining the productivity of the anode active material.

[0106] The above high-pressure adjustment process may be included in the firing stage by supplying a gas under specific conditions at a specific point in time during the firing process, and specifically, may be included in the firing stage by supplying a gas under specific conditions through the supply unit (50) of the firing section (20) equipped in the firing furnace (100). The supply of a gas under specific conditions means setting the supplied gas and the amount of gas to specific conditions. When the above high-pressure adjustment process is included in the firing stage by supplying a gas under specific conditions through the supply unit (50) of the firing section (20), the above high-pressure adjustment section refers to all firing sections (20) where the high-pressure adjustment process is performed throughout the entire firing furnace (100). That is, the length of the high-pressure adjustment section refers to the sum of the lengths of the firing sections (20) where the high-pressure adjustment process is performed, and the volume of the high-pressure adjustment section refers to the sum of the volumes of the firing sections (20) where the high-pressure adjustment process is performed.

[0107] When the above-described kiln (100) includes a plurality of firing sections (20), the high-pressure adjustment process may be performed in a specific firing section (20), and the firing section (20) where the high-pressure adjustment process is performed maintains specific gas supply conditions during the high-pressure adjustment process. As described above, the high-pressure adjustment section refers to all specific firing sections (20) where the high-pressure adjustment process is performed throughout the entire kiln (100).

[0108] In one embodiment of the present invention, the firing is performed in a firing furnace (100) comprising a plurality of firing sections (20), and the firing sections (20) in which the high-pressure adjustment process is performed are 10 to 50. Specifically, the number of firing sections (20) on which the high-pressure adjustment process is performed is 10 or more, 11 or more, 12 or more, 13 or more, 14 or more, 15 or more, 16 or more, 17 or more, 18 or more, 19 or more, 20 or more, 21 or more, 22 or more, 22 or more, 23 or more, or 24 or more, and 50 or fewer, 45 or fewer, 40 or fewer, 39 or fewer, 38 or fewer, 37 or fewer, 36 or fewer, 35 or fewer, 34 or fewer, 33 or fewer, 32 or fewer, 31 or fewer, 30 or fewer, 29 or fewer, 28 or fewer, 27 or fewer, 26 or fewer, or 25 or fewer, and 10 to 50, 15 to 40 or There may be 20 to 30 of them. When a plurality of the above-mentioned firing sections (20) are provided, the firing conditions can be finely adjusted for each firing section (20) to obtain an optimized positive active material according to the degree of growth of the firing material at each firing stage or the firing environment within the firing section (20). When the number of firing sections (20) in which the high-pressure adjustment process is performed satisfies the above range, it is possible to manufacture a positive active material having excellent characteristics through the above adjustment without reducing the efficiency and ease of manufacturing.

[0109] In one embodiment of the present invention, the total volume of the high-pressure adjustment section is 30 m 3 to 300 m 3 is. Specifically, 30 m 3 That's all, 40 m 3 That's all, 50 m 3 More than or equal to 60 m 3 That is all, 300 m 3 Below, 250 m 3 Below, 200 m3 Below, 150 m 3 Below, 100 m 3 Below, 90 m 3 Below, 80 m 3 Less than or equal to 70 m 3 Less than, and 30 m 3 to 300 m 3 , 30 m 3 to 250 m 3 or 50 m 3 to 200 m 3 It may be possible. The total volume of the high-pressure adjustment section above refers to the volume of the space in which a single calcination material moves while the high-pressure adjustment process is performed within the calcination furnace (100). More specifically, as described above, if the high-pressure adjustment process is included in the calcination stage by supplying a gas under specific conditions through the supply section (50) of the calcination section (20), it refers to the sum of the volumes of the calcination sections (20) in which the high-pressure adjustment process is performed. When the total volume of the high-pressure adjustment section satisfies the above range, it is possible to minimize the quality difference between the cathode active materials depending on the time of obtaining the calcined product after calcination is completed, without reducing the efficiency of the manufacturing process.

[0110] In one embodiment of the present invention, the total length of the high-pressure adjustment section is 10 m to 200 m. Specifically, it may be 10 m or more, 20 m or more, 30 m or more, or 40 m or more, 200 m or less, 150 m or less, 100 m or less, 90 m or less, 80 m or less, 70 m or less, 60 m or less, or 50 m or less, and may be 10 m to 200 m, 10 m to 100 m, or 20 m to 80 m. The total length of the high-pressure adjustment section above refers to the length traveled by a single calcination material within the calcination furnace (100) while the high-pressure adjustment process is performed within the calcination furnace (100). More specifically, as described above, if the high-pressure adjustment process is included in the calcination stage by supplying a gas under specific conditions through the supply section (50) of the calcination section (20), it refers to the sum of the lengths of the calcination sections (20) where the high-pressure adjustment process is performed. When the total length of the high-pressure adjustment section satisfies the above range, it is possible to minimize quality differences between cathode active materials according to the calcination time without reducing the efficiency of the manufacturing process.

[0111] The gas supplied during the above calcination can help the growth of the cathode active material precursor while preventing the generation of lithium by-products, and any gas commonly used in the relevant technical field for the manufacture of cathode active materials may be used for the above calcination; the calcination may be performed in an atmospheric or oxygen atmosphere, but is not limited thereto.

[0112] In one embodiment of the present invention, the high pressure adjustment process is performed under an atmosphere in which the purity of oxygen is 80% to 99%. Specifically, the high pressure adjustment process is performed under an atmosphere in which the purity of oxygen is 80% or higher, 81% or higher, 82% or higher, 83% or higher, 84% or higher, 85% or higher, 86% or higher, 87% or higher, 88% or higher, 89% or higher, or 90% or higher; is performed under an atmosphere in which the purity of oxygen is 99% or lower, 98% or lower, 97% or lower, 96% or lower, 95% or lower, 94% or lower, 93% or lower, 92% or lower, or 91% or lower; and can be performed under an atmosphere in which the purity is 80% to 99%, 80% to 95%, or 85% to 95%. When the purity of oxygen satisfies the above range during the above high-pressure adjustment process, the generation of lithium by-products is suppressed, thereby providing a stable calcination environment while enabling efficient growth of the active material.

[0113] The above concentration % refers to a unit in which the number of oxygen molecules in the gas is expressed as concentration % based on the total number of gas molecules in the supplied gas being 100% concentration %.

[0114] In one embodiment of the present invention, the total time required for the high-pressure adjustment process is 6 to 14 hours. Specifically, the total time required for the high-pressure adjustment process may be 6 hours or more, 7 hours or more, 8 hours or more, 9 hours or more, or 10 hours or more, 14 hours or less, 13 hours or less, 12 hours or less, or 11 hours or less, and may be 6 to 14 hours, 8 to 14 hours, or 8 to 12 hours. The total time required for the high-pressure adjustment process refers to the total time during which high-pressure adjustment is performed for a single sintered material from the start of sintering to the end of sintering.

[0115] In one embodiment of the present invention, the temperature of the high pressure adjustment process is 600°C to 1000°C. Specifically, the temperature of the high pressure adjustment process may be 600°C or higher, 650°C or higher, 700°C or higher, 750°C or higher, or 800°C or higher, 1000°C or lower, 950°C or lower, 900°C or lower, or 850°C or lower, and may be 600°C to 1000°C, 700°C to 1000°C, or 700°C to 900°C.

[0116] When the total time and temperature of the above high-pressure adjustment process satisfy the above range, the generation of by-products of the calcined material during the high-pressure adjustment process is prevented, and growth can proceed smoothly, while effectively suppressing the occurrence of quality differences between cathode active materials depending on the calcination time caused by high-pressure adjustment.

[0117] In one embodiment of the present invention, the firing step includes a heating step, a holding step, and a cooling step. The holding step refers to a step of maintaining a constant temperature without heating or cooling.

[0118] When the above-mentioned firing step includes a heating step, a holding step, and a cooling step, each step is performed at a different time for a single firing material. Additionally, the above steps may be performed separately from other steps not only in terms of time but also in terms of space. Specifically, when the firing is performed within a firing furnace (100) that includes a plurality of firing sections (20), the heating step is performed in a firing section (20) located at the inlet side where a firing container (200) is introduced from the outside and in a firing section (20) located adjacent thereto; the cooling step is performed in a firing section (20) located at the outlet side where the firing container (200) is discharged to the outside and in a firing section (20) located adjacent thereto; and the holding step may be performed in a firing section (20) located between the firing sections (20) where the heating step and the cooling step are performed.

[0119] In one embodiment of the present invention, the duration of the maintenance step is 6 hours to 14 hours. Specifically, the duration of the maintenance step may be 6 hours or more, 7 hours or more, 8 hours or more, 9 hours or more, or 10 hours or more, 14 hours or less, 13 hours or less, 12 hours or less, or 11 hours or less, and may be 6 hours to 14 hours, 8 hours to 14 hours, or 8 hours to 12 hours.

[0120] In one embodiment of the present invention, the temperature in the holding step is 600°C to 1000°C. Specifically, the temperature in the holding step may be 600°C or higher, 650°C or higher, 700°C or higher, 750°C or higher, or 800°C or higher, 1000°C or lower, 950°C or lower, 900°C or lower, or 850°C or lower, and may be 600°C to 1000°C, 700°C to 1000°C, or 700°C to 900°C.

[0121] When the temperature and duration of the above-mentioned holding step satisfy the above range, the reaction between lithium and transition metal proceeds smoothly, allowing the sintered product to exhibit stability, strength, and particle size suitable for battery application.

[0122] In one embodiment of the present invention, the high pressure adjustment process is performed in the maintenance step.

[0123] When the above calcination step includes a heating step, a holding step, and a cooling step, the heating and cooling steps involve significant temperature fluctuations; consequently, the calcination environment is unstable, and particle growth resulting from calcination generally does not occur. Therefore, since changes in calcination conditions other than temperature during the heating and cooling steps do not significantly affect the quality of the finally obtained cathode active material or the manufacturing process, the high-pressure adjustment process must be performed during the holding step to effectively prevent quality degradation caused by such changes.

[0124] If the high-pressure adjustment process described above is performed during the holding phase, the high-pressure adjustment process may be performed throughout the entire holding phase or only during a part of the holding phase. Since the degree of growth of the cathode active material or the degree of lithium byproduct generation may vary depending on the high-pressure adjustment conditions, the proportion of the high-pressure adjustment process in the holding phase can be appropriately adjusted by a person skilled in the art to suit the material or manufacturing purpose of the cathode active material.

[0125] In one embodiment of the present invention, the high pressure adjustment process is performed in the maintenance step, and the proportion of the high pressure adjustment process in the entire maintenance step is 80% to 100%. Specifically, the proportion of the high pressure adjustment process may be 80% or more, 81% or more, 82% or more, 83% or more, 84% or more, 85% or more, 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more, and 100% or less, and may be 80% to 100%, 90% to 100%, or 95% to 100%. When the proportion of the high pressure adjustment process satisfies the above range, the occurrence of quality differences or deterioration due to the high pressure adjustment process can be effectively manifested.

[0126] In one embodiment of the present invention, the calcination step is performed as a continuous process. When the calcination step for manufacturing the anode active material is performed as a continuous process, productivity can be increased compared to batch-type calcination.

[0127] In one embodiment of the present invention, the firing step is performed using a roller hearth kiln (RHK) firing method, which is a continuous firing method.

[0128] In one embodiment of the present invention, the supply amount of anode active material precursor per hour in the calcination furnace (100) is 100 kg to 2000 kg. Specifically, the supply amount of the cathode active material precursor is 100 kg or more, 150 kg or more, 200 kg or more, 250 kg or more, 300 kg or more, 350 kg or more, 400 kg or more, 450 kg or more, 500 kg or more, 550 kg or more, 600 kg or more, 650 kg or more, 700 kg or more, 750 kg or more, 800 kg or more, 850 kg or more, 900 kg or more, 950 kg or more, 1000 kg or more, 1050 kg or more, 1100 kg or more, 1150 kg or more, 1200 kg or more, or 1250 kg or more, and 2000 kg or less, 1950 kg or less, 1900 kg or less, 1850 kg or less, 1800 kg or less, 1750 kg or less, 1700 kg or less, 1650 It may be less than or equal to kg, less than or equal to 1600 kg, less than or equal to 1550 kg, less than or equal to 1500 kg, less than or equal to 1450 kg, less than or equal to 1400 kg, less than or equal to 1350 kg, or less than or equal to 1300 kg, or between 100 kg and 2000 kg, between 200 kg and 1800 kg, or between 200 kg and 1400 kg. When the supply amount of the cathode active material precursor satisfies the above range, it is possible to increase the productivity of the cathode active material while manufacturing a cathode active material of uniform quality.

[0129] The above method for manufacturing the positive electrode active material may additionally include a doping step or a coating step after the calcination step to improve characteristics such as electrical conductivity or increase stability, depending on the purpose of manufacturing the positive electrode active material. If the above manufacturing method additionally includes a doping step or a coating step, the doping or coating may be performed by mixing the calcined product after the calcination step with a doping raw material or a coating raw material and then performing heat treatment; however, it is not limited to this method as long as it is a method commonly used in the relevant technical field for manufacturing positive electrode active materials. Furthermore, the above manufacturing method may include both the doping step and the coating step.

[0130] The above doping raw material or coating raw material may be a raw material containing an element selected from the group consisting of Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, F, P, S, Y, Al, Co, and combinations thereof, but is not limited thereto as long as it is commonly used in the relevant technical field for the manufacture of cathode active materials.

[0132] positive electrode active material

[0133] The present invention provides a positive electrode active material.

[0134] In one embodiment of the present invention, the positive active material comprises a step of calcining a positive active material precursor, wherein the calcination step is performed in a calcination furnace, and wherein the calcination step comprises a high-pressure adjustment process in which a high-pressure gas is supplied into the calcination furnace, and the amount of gas supplied per hour in the high-pressure adjustment process is a unit volume (m²) of the high-pressure adjustment section in the calcination furnace. 3 8 m per ) 3 to 20 m 3 The above gas supply amount is a positive active material manufactured from a method for manufacturing a positive active material calculated based on 25℃ and 1 atm.

[0135] A positive electrode active material according to one embodiment of the present invention is manufactured by a manufacturing method including the high-pressure adjustment process, thereby exhibiting uniform quality despite differences in the timing of obtaining the sintered product after the sintering is completed, and having characteristics such as improved stability and capacity when operating the battery, as a small amount of lithium byproduct is present in the active material.

[0136] In one embodiment of the present invention, the positive electrode active material is manufactured by the method for manufacturing the positive electrode active material described above.

[0137] In one embodiment of the present invention, the positive electrode active material comprises a lithium transition metal oxide. When the lithium transition metal oxide is included in the positive electrode active material, high capacity characteristics and lifespan characteristics can be expected.

[0138] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel.

[0139] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel and further comprises a material selected from the group consisting of cobalt, manganese, aluminum, and combinations thereof.

[0140] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel and cobalt, and further comprises one selected from the group consisting of manganese, aluminum, and combinations thereof.

[0141] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel, cobalt, and manganese.

[0142] In one embodiment of the present invention, the lithium transition metal oxide comprises nickel, and the nickel content is 60 mol% to 90 mol% based on the total number of moles of transition metal in the lithium transition metal oxide. Specifically, the nickel content may be 60 mol% or more, 65 mol% or more, 70 mol% or more, 75 mol% or more, or 80 mol% or more, 90 mol% or less, or 85 mol% or less, and may be 60 mol% to 90 mol%, 70 mol% to 90 mol%, or 80 mol% to 90 mol%. When the nickel content satisfies the above range, the battery may have excellent capacity characteristics.

[0143] In one embodiment of the present invention, the lithium transition metal oxide comprises cobalt, and the content of the cobalt is 1 mol% to 20 mol% based on the total number of moles of transition metal in the lithium transition metal oxide. Specifically, the content of the cobalt is 1 mol% or more, 2 mol% or more, 3 mol% or more, or 4 mol% or more, 20 mol% or less, 15 mol% or less, 10 mol% or less, 9 mol% or less, 8 mol% or less, 7 mol% or less, 6 mol% or less, or 5 mol% or less, and may be 1 mol% to 20 mol%, 1 mol% to 15 mol%, or 2 mol% to 10 mol%. When the content of the cobalt satisfies the above range, it may have capacity characteristics suitable for battery application and facilitate operation at high voltage.

[0144] In one embodiment of the present invention, the lithium transition metal oxide comprises manganese, and the content of the manganese is 1 mol% to 40 mol% based on the total number of moles of transition metal in the lithium transition metal oxide. Specifically, the content of the manganese is 1 mol% or more, 2 mol% or more, 3 mol% or more, 4 mol% or more, 5 mol% or more, or 10 mol% or more, 40 mol% or less, 35 mol% or less, 30 mol% or less, 25 mol% or less, 20 mol% or less, or 15 mol% or less, and may be 1 mol% to 40 mol%, 5 mol% to 30 mol%, or 5 mol% to 20 mol%. When the content of the manganese satisfies the above range, it may have capacity characteristics suitable for battery application.

[0145] In one embodiment of the present invention, the lithium transition metal oxide further comprises a doping element.

[0146] In one embodiment of the present invention, the doping element is selected from the group consisting of Zr, Y, Al, Ti, Mo, W, Nb, Ta, Sr, Ca, Ba, B, and combinations thereof.

[0147] In one embodiment of the present invention, the lithium transition metal oxide is represented by the following [Chemical Formula 1].

[0148] [Chemical Formula 1]

[0149] Li a Ni b Co c M 1 d M 2 e O2

[0150] In the above chemical formula 1, M 1 It is selected from the group consisting of Mn, Al, and combinations thereof.

[0151] In one embodiment of the present invention, the M 1 is Mn.

[0152] In the above chemical formula 1, M 2is selected from the group consisting of Zr, Y, Al, Ti, Mo, W, Nb, Ta, Sr, Ca, Ba, B and combinations thereof.

[0153] In the above chemical formula 1, a is 0.8 ≤ a ≤ 1.2. Specifically, a may be 0.8 ≤ a ≤ 1.2, 0.9 ≤ a ≤ 1.2, or 0.9 ≤ a ≤ 1.1.

[0154] In the above chemical formula 1, b is 0.6 ≤ b < 1. Specifically, b may be 0.6 ≤ b < 1, 0.7 ≤ b ≤ 0.9, or 0.8 ≤ b ≤ 0.9.

[0155] In the above chemical formula 1, c is 0 ≤ c ≤ 0.2. Specifically, c may be 0 ≤ c ≤ 0.2, 0.05 ≤ c ≤ 0.2, or 0.05 ≤ c ≤ 0.15.

[0156] In the above chemical formula 1, d is 0 ≤ d ≤ 0.3. Specifically, d may be 0 ≤ d ≤ 0.3, 0.1 ≤ d ≤ 0.3, or 0.1 ≤ d ≤ 0.2.

[0157] In the above chemical formula 1, e is 0 ≤ e ≤ 0.1. Specifically, e may be 0 ≤ e ≤ 0.1, 0 ≤ e ≤ 0.05, or 0 ≤ e ≤ 0.03.

[0158] In the above chemical formula 1, b+c+d+e=1.

[0159] When the above lithium transition metal oxide particles contain a coating element, [Chemical Formula 1] represents a lithium transition metal oxide excluding the coating element.

[0160] In one embodiment of the present invention, the lithium transition metal oxide contains 0.1% to 1.5% by weight of lithium by-products based on the total weight of the lithium transition metal oxide. Specifically, the lithium byproduct may be included in an amount of 0.1 wt% or more, 0.15 wt% or more, 0.2 wt% or more, 0.25 wt% or more, 0.3 wt% or more, 0.35 wt% or more, 0.4 wt% or more, 0.45 wt% or more, 0.5 wt% or more, 0.55 wt% or more, 0.6 wt% or more, 0.65 wt% or more, 0.7 wt% or more, 0.75 wt% or more, 0.8 wt% or more, or 0.85 wt% or more, 1.5 wt% or less, 1.4 wt% or less, 1.3 wt% or less, 1.2 wt% or less, 1.1 wt% or less, 1 wt% or less, or 0.9 wt% or less, and may be included in an amount of 0.1 wt% to 1.5 wt%, 0.3 wt% to 1.2 wt%, or 0.5 wt% to 1 wt%.

[0161] The above lithium by-products refer to by-products that degrade battery performance, generated when lithium reacts with non-transition metals such as water vapor during the manufacturing process of cathode active materials; specifically, lithium hydroxide and lithium carbonate fall under this category.

[0162] When the content of the lithium byproduct satisfies the above range, a separate washing process for removing the lithium byproduct is not required, and the generation of additional byproducts caused by the washing process can be minimized.

[0163] In one embodiment of the present invention, the lithium transition metal oxide particles are composed of one or more primary particles, and the average particle size of the primary particles within the lithium transition metal oxide particles is 50 nm to 200 nm. Specifically, the average particle size of the primary particles is 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, 90 nm or more, 100 nm or more, 110 nm or more, 120 nm or more, or 125 nm or more, and 200 nm or less, 190 nm or less, 180 nm or less, 170 nm or less, 160 nm or less, 150 nm or less, 140 nm or less, 135 nm or less, or 130 nm or less, and may be 50 nm to 200 nm, 100 nm to 200 nm, or 120 nm to 150 nm. When the above average particle size satisfies the above range, it can exhibit an energy density suitable for battery utilization.

[0165] anode

[0166] The present invention also provides an anode.

[0167] In one embodiment of the present invention, the anode comprises the anode active material described above.

[0168] In one embodiment of the present invention, the anode comprises an anode active material prepared by the method for preparing an anode active material described above.

[0169] In one embodiment of the present invention, the positive electrode comprises a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector, wherein the positive electrode active material layer comprises the positive electrode active material.

[0170] The above-mentioned anode may be manufactured according to a conventional anode manufacturing method, except for using the above-mentioned anode active material. For example, the above-mentioned anode may be manufactured by dissolving or dispersing the components constituting the anode active material layer, namely the anode active material, a conductive material and / or a binder, etc., in a solvent to produce an anode composite, applying the anode composite to at least one surface of an anode current collector, and then drying and rolling; or by casting the anode composite onto a separate support and then laminating the film obtained by peeling it off from the support onto an anode current collector.

[0171] In one embodiment of the present invention, the positive current collector may include a highly conductive metal, and is not particularly limited as long as it allows the positive active material layer to adhere easily and is non-reactive within the voltage range of the battery. The positive current collector may be, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel surface treated with carbon, nickel, titanium, silver, etc. Additionally, the positive current collector may typically have a thickness of 3 μm to 500 μm, and may form fine irregularities on the surface of the current collector to increase the adhesion of the positive active material. It may be used in various forms, such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0172] In one embodiment of the present invention, the positive active material layer may include, together with the positive active material, a conductive material and a binder optionally as needed. In this case, the positive active material may be included in an amount of 80% to 99% by weight, more specifically 85% to 98.5% by weight, based on the total weight of the positive active material layer, and may exhibit excellent capacity characteristics within this range.

[0173] In one embodiment of the present invention, the conductive material is used to impart conductivity to the electrode, and in the battery being constructed, it may be used without special limitations as long as it has electronic conductivity without causing chemical changes. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fibers; metal powder or metal fibers such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and one of these alone or a mixture of two or more may be used. The conductive material may be included in an amount of 0.1% to 15% by weight relative to the total weight of the positive electrode active material layer.

[0174] In one embodiment of the present invention, the binder serves to improve adhesion between positive active material particles and adhesion between the positive active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, polymethyl methacrylate, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluororubber, polyacrylic acid, and polymers in which hydrogens thereof are substituted with Li, Na, or Ca, or various copolymers thereof, and one of these alone or a mixture of two or more may be used. The above binder may be included in an amount of 0.1% to 15% by weight relative to the total weight of the positive active material layer.

[0175] In one embodiment of the present invention, the solvent may be a solvent generally used in the art, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), dimethylformamide (DMF), acetone, or water, and one of these alone or a mixture of two or more may be used. The amount of solvent used is sufficient to dissolve or disperse the cathode active material, conductive material, binder, and dispersant, taking into account the coating thickness of the slurry and the manufacturing yield, and to have a viscosity that can exhibit excellent thickness uniformity when coated for cathode manufacturing thereafter.

[0177] lithium secondary battery

[0178] The present invention provides a lithium secondary battery.

[0179] In one embodiment of the present invention, the lithium secondary battery includes the anode described above.

[0180] In one embodiment of the present invention, the lithium secondary battery comprises the anode described above; a cathode; a separator interposed between the anode and the cathode; and an electrolyte. Additionally, the lithium secondary battery may optionally further comprise a battery container housing an electrode assembly of the anode, cathode, and separator described above, and a sealing member sealing the battery container.

[0181] In one embodiment of the present invention, the cathode may comprise a cathode current collector and a cathode active material layer located on the cathode current collector.

[0182] In one embodiment of the present invention, the negative current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery. The negative current collector may be, for example, copper, stainless steel, aluminum, nickel, titanium, or calcined carbon, and may be a copper or stainless steel surface treated with carbon, nickel, titanium, silver, etc., or an aluminum-cadmium alloy. In addition, the negative current collector may typically have a thickness of 3 μm to 500 μm, and, similar to the positive current collector, may have fine irregularities formed on the surface of the current collector to increase the adhesion of the negative active material. The negative current collector may be used in various forms, such as a film, sheet, foil, net, porous body, foam, nonwoven fabric, etc.

[0183] In one embodiment of the present invention, the negative electrode active material layer may optionally include a binder and a conductive material together with the negative electrode active material.

[0184] In one embodiment of the present invention, the negative electrode active material may be a compound capable of reversible intercalation and deintercalation of lithium. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium, such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys, or Al alloys; and SiO₂ β Examples include metal oxides capable of doping and dedoping lithium, such as (0 < β < 2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites comprising the metal compound and carbonaceous material, such as Si-C composites or Sn-C composites, and any one or more of these may be used. Additionally, a metallic lithium thin film may be used as the negative electrode active material. Furthermore, the carbon material may include low-crystallinity carbon and high-crystallinity carbon. Representative examples of the above low-crystallinity carbon include soft carbon and hard carbon, and representative examples of the above high-crystallinity carbon include amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch-derived cokes. The above negative electrode active material may be included in the negative electrode active material layer in an amount of 80% to 99% by weight based on the total weight of the negative electrode active material layer.

[0185] In one embodiment of the present invention, the binder of the negative electrode active material layer is a component that assists in the bonding between the conductive material, the active material, and the current collector, and can typically be added to the negative electrode active material layer in an amount of 0.1% to 10% by weight based on the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0186] In one embodiment of the present invention, the conductive material of the negative electrode active material layer may be added to the negative electrode active material layer in an amount of 10% by weight or less, preferably 5% by weight or less, based on the total weight of the negative electrode active material layer, as a component for further improving the conductivity of the negative electrode active material. Such a conductive material is not particularly limited as long as it possesses conductivity without causing chemical changes in the battery. For example, the conductive material may be graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers such as carbon fibers or metal fibers; fluorinated carbon; metal powders such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives.

[0187] In one embodiment of the present invention, the cathode may be manufactured by applying and drying a composition for forming a cathode active material layer, prepared by dissolving or dispersing a cathode active material and optionally a binder and a conductive material in a solvent, onto a cathode current collector, or by casting the composition for forming a cathode active material layer onto a separate support and then laminating the film obtained by peeling from the support onto a cathode current collector.

[0188] In one embodiment of the present invention, the separator separates the negative electrode and the positive electrode and provides a pathway for the movement of lithium ions. It can be used without special limitations as long as it is a separator typically used in lithium secondary batteries, and it is particularly desirable that it has low resistance to the movement of electrolyte ions and excellent electrolyte moisture retention capacity. Specifically, a porous polymer film, such as a porous polymer film made of a polyolefin-based polymer like 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 may be used. In addition, a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers, may be used. Furthermore, a coated separator containing a ceramic component or a polymer material may be used to ensure heat resistance or mechanical strength, and it may optionally be used in a single-layer or multi-layer structure.

[0189] In one embodiment of the present invention, the electrolyte may be an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, a solid inorganic electrolyte, a molten inorganic electrolyte, etc., which are usable in the manufacture of a lithium secondary battery, but is not limited thereto. As a specific example, the electrolyte may include an organic solvent and a lithium salt.

[0190] In one embodiment of the present invention, the organic solvent may be used without particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may be an ester-based solvent such as methyl acetate, ethyl acetate, γ-butyrolactone, or ε-caprolactone; an ether-based solvent such as dibutyl ether or tetrahydrofuran; a ketone-based solvent such as cyclohexanone; or an aromatic hydrocarbon-based solvent such as benzene or fluorobenzene. Carbonate-based solvents such as dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol-based solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a straight-chain, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double bond, a directional ring, or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes may be used. Among these, a carbonate-based solvent is preferred, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery, and a low-viscosity linear carbonate-based compound (e.g., ethylmethyl carbonate, dimethyl carbonate or diethyl carbonate, etc.) is more preferred.

[0191] In one embodiment of the present invention, the lithium salt may be used without particular limitation as long as it is a compound capable of providing lithium ions used in a lithium secondary battery. Specifically, as the anion of the lithium salt, F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - The lithium salt may be at least one selected from the group consisting of LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. It is preferable to use the lithium salt within the range of 0.1 M to 2.0 M. When the concentration of the lithium salt falls within the above range, the electrolyte has appropriate conductivity and viscosity, so it can exhibit excellent electrolyte performance and lithium ions can move effectively.

[0192] In one embodiment of the present invention, in addition to the electrolyte components, the electrolyte may further include one or more additives for the purpose of improving the lifespan characteristics of the battery, suppressing the decrease in battery capacity, and improving the discharge capacity of the battery, such as, for example, a haloalkylene carbonate-based compound such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylene diamine, n-glyme, triamide hexaphosphate, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salt, pyrrole, 2-methoxyethanol, or aluminum trichloride. In this case, the additive may be included in the electrolyte in an amount of 0.1% to 5% by weight relative to the total weight of the electrolyte.

[0193] A lithium secondary battery comprising a positive electrode active material according to one embodiment of the present invention stably exhibits excellent capacity characteristics, output characteristics, and lifespan characteristics, and is therefore useful in fields such as portable devices like mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs) and electric vehicles (EVs).

[0194] There are no specific restrictions on the external shape of the above lithium secondary battery, but it may be a cylindrical type using a can, a prismatic type, a pouch type, or a coin type.

[0195] A lithium secondary battery according to one embodiment of the present invention can be used not only as a battery cell used as a power source for a small device, but can also preferably be used as a unit cell in a medium-to-large battery module comprising a plurality of battery cells.

[0196] Accordingly, in one embodiment of the present invention, a battery module including the lithium secondary battery as a unit cell and a battery pack including the same are provided.

[0197] In one embodiment of the present invention, the battery module or battery pack may be used as a power source for one or more medium-to-large devices, including a power tool; an electric vehicle (EV), a hybrid electric vehicle, and a plug-in hybrid electric vehicle (PHEV); or a power storage system.

[0199] Specific embodiments of the present invention are presented below. However, the embodiments described below are merely for the purpose of specifically illustrating or explaining the present invention and do not limit the present invention. Furthermore, details not described herein can be sufficiently technically inferred by a person skilled in the art, so their description is omitted.

[0201] Examples

[0203] <Example 1>

[0204] LiOH·H2O (manufactured by SQM) as a lithium raw material at 33 wt% of the total mixture, and Ni as a transition metal raw material 0.83 Co 0.05 Mn 0.12 (OH)2 (HUAJIN NEW ENERGY MATERIALS, HJ803S) was added to the total mixture at 67% by weight, and then mixed at 2,000 rpm for 5 minutes using an intensive mixer (EIRICH, R08W).

[0205] After heating the above mixture to 810°C in a Roller Hearth Kiln (RHK), oxygen at a concentration of 90% (where the number of oxygen molecules is 90% based on 100% of the total number of gas molecules) is introduced at 810°C for 10 hours into a unit volume (m³) of a high-pressure adjustment section. 3 ) 9.2 m per 3The entire holding stage was maintained as a high-pressure adjustment process by supplying it. After the holding stage, the firing was terminated through cooling, and subsequently, the fired product was ground to a particle size of 1 μm to 10 μm to produce an anode active material.

[0206] During the above-mentioned cathode active material manufacturing process, 250 kg of cathode active material precursor was supplied to the kiln per hour, and the cathode active material manufactured from the first calcined product obtained in the above-mentioned continuous process in the Roller Hearth Kiln (RHK) was set as Example 1.

[0207] The above high-pressure adjustment process was performed in a total of 25 firing sections, and the total length of the high-pressure adjustment section within the firing furnace is 40.5 m, and the volume is 67.5 m³ 3 am.

[0209] <Example 2>

[0210] The positive active material prepared from a calcined product obtained with a 10-hour interval difference after obtaining the calcined product for the preparation of Example 1 was prepared through the same continuous process as Example 1 above, and was set as Example 2.

[0212] <Comparative Example 1>

[0213] The gas supply amount of the high-pressure adjustment process of the example is the unit volume (m²) of the high-pressure adjustment section. 3 ) 6.2 m per 3 The positive electrode active material of Comparative Example 1 was prepared in the same manner as in Example 1, except that it was controlled by [specific method].

[0215] <Comparative Example 2>

[0216] The gas supply amount of the high-pressure adjustment process of the example is the unit volume (m²) of the high-pressure adjustment section. 3 ) 6.2 m per 3 The positive active material of Comparative Example 2 was prepared in the same manner as in Example 2, except that it was controlled by [specific method].

[0218] Experimental Example

[0220] <Experimental Example 1: Analysis of Structural Characteristics>

[0221] The structural characteristics of the positive electrode active materials prepared according to the above examples and comparative examples were analyzed using an X-ray diffraction analyzer (XRD). Specifically, 2 to 3 g of each positive electrode active material powder was collected, and X-ray diffraction was analyzed using an XRD (Bruker, D8 Endeavor) with Cu-Kα rays (wavelength 1.54 Å) in the 2θ range of 8° to 105° at a scan speed of 0.1° / sec and an acceleration voltage of 20 kV / 5 mA. Through this, the a-axis length, c-axis length, cell volume, and the size of primary particles within the active material of each positive electrode active material were derived. The structural characteristics of the positive electrode active materials derived by the above method are shown in [Table 1] below.

[0223] <Experimental Example 2: Analysis of Lithium By-product Content>

[0224] To analyze the lithium byproduct content of the cathode active materials prepared according to the above examples and comparative examples, 5 g of the calcined product and 5 g of the washed product, which was washed and dried, were each stirred in 100 mL of distilled water for 5 minutes, and after filtration, the filtered solution was titrated with a 0.1 N aqueous HCl solution. Subsequently, a titration curve was obtained using a Metrohm pH meter, and the equivalence points of lithium hydroxide (LiOH) and lithium carbonate (Li2CO3) were determined from the titration curve to calculate the lithium byproduct content (lithium hydroxide, lithium carbonate, and the sum of lithium hydroxide and lithium carbonate). The lithium byproduct content of the cathode active materials calculated by the above method is shown in [Table 1] below.

[0226] a Axis length (Å) c-axis length (Å) Cell volume (Å) 3 ) Primary particle size (nm) Example 1 2.8673 14.1879 101.0202 129.94 Example 2 2.8674 14.1884 101.0282 132.15 Comparative Example 1 2.8672 14.1903 101.0259 122.04 Comparative Example 2 2.8672 14.1892 101.0202 132.22

[0228] Lithium byproduct content (weight%) Li2CO3 LiOH Total content Example 1 0.388 0.480 0.868 Example 2 0.407 0.487 0.894 Comparative Example 1 0.379 0.506 0.885 Comparative Example 2 0.386 0.508 0.894

[0230] As shown in [Table 1] and [Table 2] above, the gas supply amount per hour is the unit volume (m³) of the high-pressure adjustment section within the kiln. 3 8 m per ) 3 to 20 m 3 When a positive electrode active material is prepared using the manufacturing method of Example 1 and Example 2, which includes a high-pressure adjustment process, it can be seen that the two positive electrode active materials exhibit nearly equivalent quality despite the time interval between preparations, and the lithium byproduct content within the positive electrode active material can be maintained at a low level.

[0231] In contrast, when a positive electrode active material is manufactured using the manufacturing methods of Comparative Example 1 and Comparative Example 2, in which high-pressure gas is not supplied during the maintenance phase, it can be confirmed that the difference in primary particle size is greater than 5 nm depending on the difference in manufacturing time, and thus the quality of the positive electrode active material is not maintained.

[0232] Therefore, the gas supply rate per hour is the unit volume (m²) of the high-pressure adjustment section within the kiln. 3 8 m per ) 3 to 20 m 3 It can be seen that when a cathode active material is manufactured using a manufacturing method that includes a high-pressure adjustment process, both the content of lithium byproducts in the cathode active material and quality changes due to differences in manufacturing time can be improved.

[0234] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention. Explanation of the symbols

[0235] 100: Kiln 200: Firing vessel 300: Roller 10: Opening / closing part 20: Minor part 30: Moving part 40: Heating part 50: Supply unit

Claims

Claim 1 The method includes a step of calcining a positive electrode active material precursor, wherein the calcination step is performed in a calcination furnace, and wherein the calcination step includes a high-pressure adjustment process in which high-pressure gas is supplied into the calcination furnace, and wherein the gas supply amount per hour of the high-pressure adjustment process is a unit volume (m²) of the high-pressure adjustment section in the calcination furnace. 3 8 m per ) 3 to 20 m 3 A method for manufacturing a positive electrode active material, wherein the above gas supply amount is calculated based on 25℃ and 1 atm. Claim 2 A method for manufacturing a positive electrode active material according to claim 1, wherein the high pressure adjustment process is performed under an atmosphere in which the purity of oxygen is 80% to 99%. Claim 3 A method for manufacturing a positive electrode active material according to claim 1, wherein the total time required for the high-pressure adjustment process is 6 to 14 hours. Claim 4 A method for manufacturing an anode active material according to claim 1, wherein the temperature of the high-pressure adjustment process is 600℃ to 1000℃. Claim 5 A method for manufacturing an anode active material according to claim 1, wherein the calcination step comprises a heating step, a holding step, and a cooling step, and the high pressure adjustment process is performed during the holding step. Claim 6 A method for manufacturing an anode active material according to claim 1, wherein the calcination step is performed as a continuous process. Claim 7 A method for manufacturing an anode active material according to claim 1, wherein the calcination step is performed by a roller hearth kiln (RHK) calcination method, which is a continuous calcination method. Claim 8 A method for manufacturing a positive active material according to claim 6, wherein the amount of positive active material precursor supplied per hour in the calcination furnace is 100 kg to 2000 kg. Claim 9 In claim 1, the total volume of the high-pressure adjustment section is 30 m 3 to 300 m 3 A method for manufacturing a positive electrode active material. Claim 10 A method for manufacturing a positive electrode active material according to claim 1, wherein the total length of the high-pressure adjustment section is 10 m to 200 m. Claim 11 A method for manufacturing an anode active material according to claim 1, wherein the calcination furnace comprises a plurality of calcination sections, and the calcination sections where the high-pressure adjustment process is performed number from 10 to 50. Claim 12 A method for manufacturing a positive electrode active material according to claim 1, wherein the positive electrode active material comprises a lithium transition metal oxide, and the lithium transition metal oxide comprises 0.1% to 1.5% by weight of a lithium byproduct based on the total weight of the lithium transition metal oxide. Claim 13 A method for manufacturing a positive electrode active material according to claim 1, wherein the positive electrode active material comprises a lithium transition metal oxide, the lithium transition metal oxide particles are composed of one or more primary particles, and the average particle size of the primary particles within the lithium transition metal oxide particles is 50 nm to 200 nm.

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