Manufacturing method for positive electrode active material precursor

Abstract

A manufacturing method for a positive electrode active material precursor according to an embodiment of the present invention comprises: a nucleation step of forming a nucleus of the precursor in a first reactor; and a nucleus growth step of growing the nucleus, formed in the nucleation step, in a second reactor. The second reactor has a greater capacity than the first reactor.

Description

Method for manufacturing a cathode active material precursor

[0001] The present invention relates to a method for manufacturing a positive electrode active material precursor, and more particularly, to a method for manufacturing a positive electrode active material precursor using a reactor.

[0002] The recent expansion of the battery electric vehicle (BEV) market has led to an increasing demand for secondary batteries. Secondary batteries typically include a cathode, anode, an electrolyte, and a separator. The cathode and anode include active materials capable of intercalating and deintercalating lithium ions, for example. Lithium transition metal oxides are representative examples of cathode active materials. For example, lithium transition metal oxides can be manufactured by mixing a lithium precursor with a cathode active material precursor. Nickel-cobalt-manganese (NCM) compounds are widely used as cathode active material precursors.

[0003] A positive electrode active material precursor can be manufactured by performing a nucleation step and a growth step for growing the formed nuclei within a reactor. In this specification, unless otherwise stated, precursor particles may refer to the positive electrode active material precursor. Typically, after the nucleation step, a nucleus growth step is performed in the same reactor in which the nucleation step was performed. Accordingly, the production volume of the positive electrode active material precursor is affected by the size of the reactor and the reaction time.

[0004] However, as the size of the reactor increases, it becomes difficult to processively control the average particle diameter and size distribution of the precursor particles obtained through the nucleation and growth steps. In addition, new nuclei may continuously be generated during the nucleation growth step, and the nuclei generated during the nucleation growth step may not grow sufficiently, which may result in problems with the average particle diameter and size distribution of the precursor particles. To prevent this, technologies have been developed to control the process conditions of the nucleation and nucleation growth steps. However, these technologies performed the nucleation and growth steps in the same reactor, which was inconvenient because the process conditions had to be reset every time the process transitioned from the nucleation step to the nucleation growth step. Furthermore, when nucleation and growth were performed in the same reactor, there was a problem that the line of balance (LOB) deteriorated, which reduced the production yield of the cathode active material precursor.

[0005] The present invention relates to a manufacturing method for obtaining a positive electrode active material precursor having a uniform particle size distribution and for increasing the production amount of the positive electrode active material precursor, and provides a method for maximizing the production amount of the positive electrode active material precursor by using different reactors in a nucleus generation step and a nucleus growth step.

[0006] A method for manufacturing a positive electrode active material precursor according to one aspect of the present invention may include a nucleus generation step of forming a nucleus of the precursor in a first reactor; and a nucleus growth step of growing the nucleus formed in the nucleus generation step in a second reactor, wherein the capacity of the second reactor may be greater than the capacity of the first reactor.

[0007] According to one aspect of the present invention, the capacity of the second reactor may be 3.7 to 9.2 times the capacity of the first reactor.

[0008] According to one aspect of the present invention, the capacity of the second reactor is 33 m3 55m inland 3 It could be.

[0009] According to one aspect of the present invention, the progress time of the nucleus generation step may be shorter than the progress time of the nucleus growth step.

[0010] According to one aspect of the present invention, the first reactor may include a plurality of first reactors, and the nucleus generation step may be performed in each of the plurality of first reactors, and in the nucleus growth step, nuclei formed from each of the plurality of first reactors may grow together in the second reactor.

[0011] According to one aspect of the present invention, each of the nucleation steps performed in the plurality of first reactors can be performed simultaneously with each other.

[0012] According to one aspect of the present invention, each of the nucleation steps performed in the plurality of first reactors can be performed non-simultaneously with each other.

[0013] According to one aspect of the present invention, the nucleation step may include: a first nucleation step of forming nuclei of the precursor in the first reactor; and a second nucleation step of further forming nuclei of the precursor in the first reactor after completion of the first nucleation step, wherein at least a portion of the second nucleation step may be performed during a nucleus growth step of growing nuclei formed in the first nucleation step.

[0014] According to one aspect of the present invention, the nucleus generation step may include: a first nucleus generation step of forming nuclei of the precursor in the first reactor; and a second nucleus generation step of further forming nuclei of the precursor in the first reactor after completion of the first nucleus generation step, and in the nucleus growth step, the nuclei formed in the first nucleus generation step and the nuclei formed in the second nucleus generation step may grow simultaneously.

[0015] According to one aspect of the present invention, the method for manufacturing the positive electrode active material precursor may further include a storage step of storing the nuclei formed in the nucleus generation step in a storage tank, and in the nucleus growth step, the nuclei stored in the storage step may grow in the second reactor.

[0016] According to one aspect of the present invention, in the storage step, the nucleus can be stored at 40°C to 60°C.

[0017] According to one aspect of the present invention, in the storage step, the nucleus can be stored at pH 9.1 to pH 13.7.

[0018] According to one aspect of the present invention, the storage step can be performed for 48 hours or less.

[0019] According to one aspect of the present invention, the nucleation step may include supplying an initial reactant to the first reactor, wherein the initial reactant may be supplied such that the liquid level of the initial reactant is 20% to 30% of the height of the first reactor.

[0020] According to one aspect of the present invention, the nucleus growth step may include supplying an initial reactant to the second reactor, wherein the initial reactant may be supplied such that the liquid level of the initial reactant is 20% to 30% of the height of the second reactor.

[0021] According to the present invention, by using different reactors in the nucleation and nucleus growth stages, line formation efficiency and nucleus production can be increased. Furthermore, by introducing a storage stage between the nucleation and nucleus growth stages, line formation efficiency can be maximized.

[0022] Figure 1 is a schematic diagram exemplifying a reactor according to one embodiment of the present invention.

[0023] Figure 2 is a process flow diagram showing a method for manufacturing a positive electrode active material precursor according to one embodiment of the present invention.

[0024] Figure 3 is a schematic diagram showing the first reactor and the second reactor when the nucleus growth step is performed after the nucleus generation step of Figure 2.

[0025] Figure 4 is a schematic diagram showing the first reactor, the storage tank, and the second reactor when the nucleus growth step is performed after the nucleus generation step of Figure 2 is performed through the storage step.

[0026] In describing the present invention, if it is judged that the detailed description of related known functions that are obvious to those skilled in the art and may unnecessarily obscure the gist of the present invention, will be omitted.

[0027] FIG. 1 is a schematic diagram illustrating a reactor according to one embodiment of the present invention. The reactor (10) of FIG. 1 can be utilized in both the nucleation and nucleus growth stages. While the reactors in the nucleation and nucleus growth stages may differ in size, their overall configurations and shapes may be similar. In this specification, the reactor (10) in the nucleation stage may be referred to as a first reactor, and the reactor (10) in the nucleus growth stage may be referred to as a second reactor.

[0028] Referring to FIG. 1, the reactor (10) includes a reaction vessel (11). The reaction vessel (11) is a vessel into which reactants are supplied and in which nuclei generation and growth steps are performed. In this specification, the capacity of the reactor (10) may be defined as the capacity of the reaction vessel (11).

[0029] The reactor (10) may include a mixing shaft (12) and an impeller (13) extending from the top to the bottom of the reaction vessel (11). The impeller (13) may be two or more stages of impellers (13) at different levels, and for example, as shown in FIG. 1, three stages of impellers (13) may be mounted on the mixing shaft (12). The main motor (14) and the reducer (15) provide power to the mixing shaft (12), thereby allowing the impeller (13) to rotate within the reaction vessel (11). By allowing the two or more stages of impellers (13) to rotate, the slurry within the reaction vessel (11) may be evenly stirred throughout the entire region of the reaction vessel (11), i.e., from the lower region to the upper region. For example, the lowermost impeller (13b) may have a wider width than the other upper impellers (13a). This prevents the problem of unreacted solution remaining at the bottom of the reaction vessel (11), and enables the production of a precursor of uniform quality. There is no limitation on the shape of the impeller (13), and it can be designed to have an optimal shape for effective stirring of the slurry. For example, each impeller (13) may have four blades.

[0030] A chiller (16) may be provided to reduce the load on the reducer (15). The chiller (16) may be provided between the reaction vessel (11) and the main motor (14), and as cooling water circulates through the chiller (16), the load on the reducer may be reduced. The temperature in the chiller (16) may be monitored through a temperature sensor (not shown). For example, the chiller (16) may be in the form of a plurality of jackets (for example, two).

[0031] A supply pipe (17) can extend from the upper region to the lower region of the reaction vessel (11). Through the supply pipe (17), an inert gas (e.g., nitrogen gas) can be supplied into the solution in the nucleation and growth stages, and dissolved oxygen in the solution can be removed.

[0032] As the reaction progresses with the introduction of reactants, the liquid level (h) of the solution in the reaction vessel (11) increases. To reduce the load on the impeller (13) due to this, a flange coupling (not shown) may be additionally provided on the upper portion of the reactor (10).

[0033] For example, the capacity of the first reactor is 6m 3 9m inland 3 It can be. In this specification, expressions such as "A to B" are used to mean "A or more and B or less." The first reactor can include a three-stage impeller (13), and the width of the lowest impeller (13b) can be 920 mm to 1,300 mm, which is 1.05 to 1.3 times larger than that of the other upper impeller (13a). The lowest impeller (13b) can be spaced apart from the bottom surface inside the reaction vessel (11) by 130 mm to 198 mm. The distance between the three-stage impellers (13) can be spaced apart by 700 mm to 1,050 mm.

[0034] For example, the capacity of the second reactor is 33 m 3 55m inland 3 It can be. The second reactor can include a three-stage impeller (13), and the width of the lowest impeller (13b) can be 1,580 mm to 2,633 mm, which can be 1.05 to 1.3 times larger than that of the other upper impeller (13a). The lowest impeller (13b) can be spaced apart from the bottom surface inside the reaction vessel (11) by 188 mm to 1,313 mm. The distance between the three-stage impellers (13) can be spaced apart by 1,300 mm to 2,167 mm.

[0035] FIG. 2 is a process flow diagram showing a method for manufacturing a positive electrode active material precursor according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing a first reactor and a second reactor when a nucleus growth step is performed after performing the nucleus generation step of FIG. 2. FIG. 4 is a schematic diagram showing a first reactor, a storage tank, and a second reactor when a nucleus growth step is performed after performing the nucleus generation step of FIG. 2 through a storage step. Hereinafter, a method for manufacturing a positive electrode active material precursor according to an embodiment of the present invention will be described with reference to FIGS. 2 to 4.

[0036] Nucleation stage (S10)

[0037] A nucleation step (S10) may be performed in the first reactor. Through the nucleation step (S10), nuclei of a positive electrode active material precursor may be formed. Specifically, when a transition metal compound solution, a nitrogen-containing compound solution, and a basic compound solution are introduced into the first reactor and stirred, the transition metals in the transition metal compound solution may co-precipitate, thereby forming precursor particle nuclei in the form of transition metal hydroxide. At this time, the stirring speed (e.g., the rotation speed of the mixing shaft) may be 10 rpm to 300 rpm. If the stirring speed is less than 10 rpm, the reactants are not well mixed, and nucleation does not proceed smoothly. If the stirring speed is greater than 300 rpm, the friction between the impeller and the solution increases, which may generate a large number of unnecessary fine particles, making it difficult to obtain precursor particles of consistent quality. During stirring, the load on the reducer may be reduced by providing cooling water at a temperature of 8°C or lower to the chiller.

[0038] During the nucleation step (S10), initial reactants for the nucleation reaction may be supplied into the first reactor. For example, the initial reactants may include deionized water, a nitrogen-containing compound solution, and a basic compound solution. The initial reactants may be supplied so as to have a liquid level of 20% to 30% of the height of the first reactor. If the liquid level of the initial reactants is lower than 20%, friction between the reactants introduced later and the impeller continues to occur, resulting in the formation of a large number of unintended fine particles, which in turn result in a particle size difference in the final product due to the fine particles, ultimately lowering the quality of the final product. If the liquid level of the initial reactants is higher than 30%, the amount of reactants that can be introduced later is reduced, resulting in a decrease in production. For example, when a reactor including a three-stage impeller is used as the first reactor, the initial reactants may be supplied in an amount that submerges the lower and middle impellers.

[0039] During the nucleation step (S10), the solution temperature can be maintained between 40°C and 60°C. If the solution temperature is lower than 40°C, the reaction between reactants is reduced, resulting in a decrease in nucleation efficiency. If the solution temperature is higher than 60°C, the formed nuclei become coarse and non-uniformly aggregated, ultimately reducing the capacity and efficiency of the positive electrode active material.

[0040] The transition metal compound solution may include at least one selected from the group consisting of nickel, cobalt, and manganese. For example, the transition metal compound solution may include a nickel-cobalt-manganese compound.

[0041] The transition metal-containing raw material may include at least one selected from the group consisting of acetate, carbonate, nitrate, sulfate, halite, sulfide, oxide, hydrate, hydroxide, and oxyhydroxide of the transition metal, but is not limited thereto. Preferably, the transition metal-containing raw material may include a hydrate of the transition metal, and the hydrate of the transition metal has the advantage of being easy to store and use.

[0042] The transition metal compound solution can be prepared by dissolving a nickel-containing raw material, a cobalt-containing raw material, and a manganese-containing raw material in water. The nickel-containing raw material can include at least one selected from the group consisting of Ni(OH)2, NiO, NiOOH, NiCO3·2Ni(OH)2·4H2O, NiC2O2·2H2O, Ni(NO3)2·6H2O, NiSO4, NiSO4·6H2O, fatty acid nickel salts, nickel halides, and combinations thereof. The cobalt-containing raw material can be CoSO 4, It may include at least one selected from the group of Co(OH)2, CoOOH, Co(OCOCH3)2ㆍ4H2O, Co(NO3)2ㆍ6H2O, CoSO4ㆍ7H2O, Co(SO4)2ㆍ7H2O, and combinations thereof. The manganese-containing raw material may include at least one selected from the group of manganese oxides such as Mn2O3, MnO2, and Mn3O4, manganese salts such as MnCO3, Mn(NO3)2, MnSO4, MnSO4ㆍH2O, manganese acetate, manganese dicarboxylic acid salts, manganese citrate, and manganese fatty acid salts, oxyhydroxides, manganese chloride, and combinations thereof. For example, NiSO4ㆍ6H2O may be used as the nickel-containing raw material, CoSO4ㆍ7H2O may be used as the cobalt-containing raw material, and MnSO4ㆍH2O may be used as the manganese-containing raw material.

[0043] When the positive electrode active material precursor further includes a metal element (M) other than nickel (Ni), manganese (Mn), and cobalt (Co), a raw material containing the metal element (M) may be optionally further added when preparing a transition metal compound solution. The metal element (M) may include at least one selected from the group consisting of W, Y, Ba, Ca, Mo, Cr, Al, Zr, Ti, Mg, Ta, and Nb. In addition, the raw material containing the metal element (M) may include at least one selected from the group consisting of acetate, carbonate, nitrate, sulfate, halite, sulfide, hydroxide, oxyhydroxide, and oxide of the metal element (M), but is not limited thereto.

[0044] The nitrogen-containing compound solution may include an ammonium cation complex forming agent. The ammonium cation complex forming agent may include at least one selected from the group consisting of NH4OH, (NH4)2SO4, NH4NO3, NH4Cl, CH3COONH4, and NH4CO3. For example, the nitrogen-containing compound solution may be prepared by dissolving the ammonium cation complex forming agent in a solvent. In this case, the solvent may be water or a mixture of water and an organic solvent (e.g., alcohol, etc.).

[0045] The basic aqueous solution may include at least one selected from the group consisting of alkali metal hydrates, alkali metal hydroxides, alkaline earth metal hydrates, and alkaline earth metal hydroxides. For example, the basic aqueous solution may be prepared by dissolving at least one selected from the group consisting of NaOH, KOH, and Ca(OH)2 in a solvent.

[0046] Nuclear growth stage (S20)

[0047] A nucleus growth step (S20) can be performed to grow the formed nuclei. Through the nucleus growth step (S20), the positive electrode active material precursor can reach the target size. Specifically, by introducing a transition metal compound solution, a nitrogen compound solution, and a basic compound solution into the second reactor and stirring them, the precursor particle nuclei can grow. At this time, the stirring speed (e.g., the rotation speed of the mixing shaft) can be 10 rpm to 150 rpm. If the stirring speed is less than 10 rpm, the reactants are not well mixed, and nucleus growth does not proceed smoothly. If the stirring speed is greater than 150 rpm, the friction between the impeller and the solution increases, which may newly generate unnecessary fine particles, making it difficult to obtain precursor particles of consistent quality. During stirring, the load on the reducer can be reduced by providing cooling water at a temperature of 8°C or lower to the chiller.

[0048] By performing the nucleus growth step (S20) separately from the nucleus generation step (S10) in a different reactor, the line formation efficiency can be increased compared to when performing nucleus generation and growth in the same reactor.

[0049] During the nucleus growth step (S20), initial reactants for the nucleus growth reaction may be supplied into the second reactor. For example, the initial reactants may include deionized water, a nitrogen-containing compound solution, and a basic compound solution. The initial reactants may be supplied so as to have a liquid level of 20% to 30% of the height of the first reactor. If the liquid level of the initial reactants is lower than 20%, friction between the reactants introduced later and the impeller continues to occur, resulting in the formation of a large number of unintended fine particles, which in turn result in a particle size difference in the final product due to the fine particles, ultimately lowering the quality of the final product. If the liquid level of the initial reactants is higher than 30%, the amount of reactants that can be introduced later is reduced, resulting in a decrease in production. For example, when a reactor including a three-stage impeller is used as the second reactor, the initial reactants may be supplied in an amount that submerges the lower and middle impellers.

[0050] During the nucleus growth step (S20), the solution temperature can be maintained between 40°C and 60°C. If the solution temperature is lower than 40°C, the reaction between reactants is reduced, resulting in reduced nucleus growth efficiency. If the solution temperature is higher than 60°C, the growing nuclei become coarse and non-uniformly aggregated, ultimately reducing the capacity and efficiency of the positive electrode active material.

[0051] For example, the nucleus growth step (S20) may be performed on nuclei formed in the nucleus generation step (S10) and then directly transferred from the first reactor to the second reactor. Alternatively, as another example, the nucleus growth step (S20) may be performed on nuclei formed in the nucleus generation step (S10) and then transferred from the first reactor to a storage tank, and then transferred to the second reactor after performing the storage step (S40) described below.

[0052] Washing and drying stage (S30)

[0053] After the nuclear growth step (S20) is completed, the solution within the second reactor may be transferred, followed by a washing and drying step (S30). Through the washing and drying step (S30), unnecessary reaction byproducts and moisture within the solution are removed, ultimately yielding a cathode active material precursor.

[0054] Save step (S40)

[0055] The nuclei formed in the nucleation step (S10) can be transferred from the first reactor to a storage tank in the form of a reaction solution and stored (storage step (S40)). Finally, in order to uniformly control the average particle diameter and particle size distribution of the precursor particles, the storage step (S40) requires suppression of unintended nucleation and / or nucleus growth. To suppress nucleation and nucleus growth, the storage temperature, internal pH, and / or storage time in the storage step (S40) can be controlled. For example, the nuclei can be stored at 40°C to 60°C in the storage step. For example, the nuclei can be stored at pH 9.1 to pH 13.7 in the storage step. For example, the storage step can be performed for 48 hours or less. By satisfying the above numerical ranges during the storage step, unintended nucleation and / or nucleus growth can be suppressed, and as a result, the average particle diameter and particle size distribution of the precursor particles can be easily controlled. In Fig. 4, the capacity of the storage tank is shown to be similar to the capacity of the first reactor, but is not limited thereto, and storage tanks of various capacities may be used.

[0056] The storage step (S40) may be optionally performed. For example, the storage step (S40) may not be performed, in which case, as illustrated in FIG. 3, the nuclei formed in the first reactor may be directly transferred to the second reactor. As another example, the storage step (S40) may be performed, in which case, as illustrated in FIG. 4, the nuclei formed in the first reactor may be transferred to a storage tank, and after undergoing the storage step (S40), transferred from the storage tank to the second reactor.

[0057] The capacity of the first reactor is defined as V1, and the capacity of the second reactor is defined as V2. In this case, V2 can be larger than V1. For example, V1 is 6 m 3 9m inland 3 It can be, and V2 is 33m 3 55m inland 3 It can be. Generally, in a large reactor, it is difficult to control the reaction between reactants in the entire area within the reactor, so there is a problem that it is difficult to produce precursor particles with a desired size and distribution. However, in the present invention, in the nucleus generation step (S10) where process control is difficult, the first reactor is set to a small capacity, but the capacity of the second reactor is set to a large capacity, so that a large number of nuclei can be grown with only one second reactor. That is, in the nucleus generation step (S10), process conditions can be easily controlled by using a reactor with a small capacity, while in the nucleus growth step (S20), the production volume can be increased by using a reactor with a large capacity.

[0058] For example, V2 may be 3.7 to 9.2 times V1. If V2 is less than 3.7 times V1, the capacity of the second reactor may be insufficient, so that the effect of increasing the production volume may be minimal, or the capacity of the first reactor may be large, so that it may be difficult to control the process conditions in the nucleus generation step (S10). If V2 is more than 9.2 times V1, the second reactor may be excessively large, so that it may be difficult to control the process conditions in the nucleus growth step (S20), or the capacity of the first reactor may be excessively small, so that the progress speed and production amount in the nucleus generation step (S10) may decrease.

[0059] By setting V2 to be greater than V1, multiple nucleation steps (S10) can be performed to perform one nucleation growth step (S20). That is, by corresponding one nucleation growth step (S20) to multiple nucleation steps (10), the line formation efficiency can be increased. In addition, the time for performing one nucleation step (S10) (e.g., 24 hours) can be shorter than the time for performing one nucleation growth step (S20) (e.g., 48 hours). At this time, by appropriately introducing a storage step (S40), the line formation efficiency can be maximized despite the difference in the capacity and number of reactors in the nucleation step (S10) and the nucleation growth step (S20), and / or the difference in reaction time. Hereinafter, cases in which the line formation efficiency is increased according to the concept of the present invention will be exemplified.

[0060] For example, to perform a single nucleus growth step (S20), a nucleus generation step (S10) may be performed in multiple first reactors. That is, nuclei formed from each of the multiple first reactors may grow together in a single second reactor. At this time, the nucleus generation steps (S10) performed in each of the multiple first reactors may be performed simultaneously. In this case, the formed nuclei may be transferred to the second reactor without performing the storage step (S40). Alternatively, if the performance of the nucleus growth step (S20) is not yet ready, the generated nuclei may be transferred to the second reactor after performing the storage step (S40).

[0061] Alternatively, as another example, nuclei formed from each of a plurality of first reactors may be grown together in a single second reactor. In this case, the nuclei generation steps (S10) performed in each of the plurality of first reactors may be performed non-simultaneously. In this case, the nuclei formed first may be stored in a storage tank, and after nuclei generation is completed in all of the first reactors, they may be transferred to the second reactor. In other words, even if nuclei are generated at different times in the plurality of first reactors, the nuclei may be grown in the same nuclei growth step (S20) by utilizing the storage step (S40). As a result, the line formation efficiency in the nuclei generation step (S10) and the nuclei growth step (S20) may be increased.

[0062] Alternatively, as another example, a first nucleation step (S10) may be performed in a first reactor. After completion of the first nucleation step (S10), a second nucleation step (S10) may be performed in the first reactor to form new nuclei, and a nucleus growth step (S20) may be performed on the nuclei formed through the first nucleation step (S10) in a second reactor. At least a portion of the second nucleation step (S10) may be performed while the nucleus growth step (S20) is being performed. That is, multiple nucleus generation steps (S10) may be continuously performed in the first reactor, separately from the nucleus growth step (S20) being performed in the second reactor. Furthermore, considering that the duration of the nucleus generation step (S10) is relatively short, the nucleus generation step (S10) may be performed more times than the nucleus growth step (S20) during the same period of time. Through this, the difference between the amount of nuclei produced and the amount of nuclei grown can be minimized despite the difference between V1 and V2, and the line formation efficiency can be maximized.

[0063] Alternatively, as another example, a first nucleus generation step (S10) may be performed in a first reactor. After completion of the first nucleus generation step (S10), a second nucleus generation step (S10) may be performed in the first reactor to form new nuclei, and the nuclei formed in the first nucleus generation step (S10) may be stored in a storage tank. After completion of the second nucleus generation step (S10), a nucleus growth step (S20) may be performed in the second reactor to simultaneously grow the nuclei formed through the first nucleus generation step (S10) and the second nucleus generation step (S10). That is, by utilizing the storage step (S40), nuclei formed multiple times in one first reactor may be grown through a single nucleus growth step (S20). Through this, line formation efficiency may be maximized.

[0064] Hereinafter, the results of the analysis of particle size, specific surface area, and density between precursor particles in Examples 1 to 4 and the Comparative Example will be described. In Examples 1 to 4, according to the concept of the present invention, the nucleus generation step (S10) and the nucleus growth step (S20) were carried out in separate reactors. In the Comparative Example, the nucleus generation and nucleus growth were carried out in the same reactor. The process conditions of Examples 1 to 4 and the Comparative Example are as follows.

[0065] [Example 1]

[0066] 6m 3 A nucleation step (S10) was performed in the first reactor of the capacity. Pure water, a 25% NaOH solution, and a 9% NH4OH solution were supplied as initial reactants of the nucleation step (S10). Hereinafter, '%' indicating the concentration of the solution (e.g., NaOH solution or NH4OH solution) means 'mass%'. Pure water was supplied so as to satisfy a numerical range of 1,713.6 kg to 2,570.4 kg, the 25% NaOH solution so as to satisfy a numerical range of 12.8 kg to 19.2 kg, and the 9% NH4OH solution so as to satisfy a numerical range of 73.6 kg to 110.4 kg, and within the numerical ranges, the total amount of the initial reactants was supplied so as to have a liquid level of 25% of the height of the first reactor.

[0067] Afterwards, 2.4 M NCM solution, 25% NaOH solution, and 9% NH4OH solution were introduced into the first reactor, and the flow rate of 2.4 M NCM solution was controlled to 634.4 kg / hr to 951.6 kg / hr, the flow rate of 25% NaOH solution was controlled to 360.0 kg / hr to 540.0 kg / hr, and the flow rate of 9% NH4OH solution was controlled to 44.8 kg / hr to 67.2 kg / hr. The average particle size of the formed nuclei was D 50In order to make the particle size close to the target value of 3.1 μm, the above solutions were fed for 24 hours. While the nucleation step (S10) was performed, the temperature of the solution in the first reactor was maintained at 40°C to 60°C. The input flow rate of the 25% NaOH solution was controlled within a range of 2% of the supply flow rate so that the solution in the first reactor had a pH value of 10.1 to 15.1 at the beginning of the nucleation step (S10) and a pH value of 9.1 to 13.7 at the end. Here, the pH value of the solution is a value measured based on 25°C, not the process temperature (i.e., 40°C to 60°C). In order to remove dissolved oxygen in the solution, nitrogen gas was fed through the supply pipe at a rate of 150 Nm 3 / hr was input. The rotation speed of the mixing shaft in the first reactor was set to 222 rpm when the reaction between the reactants began, and was then gradually reduced to 175 rpm when the reaction ended.

[0068] The nuclei formed in the nucleus generation step (S10) were transferred to a storage tank and then transferred again to the second reactor, where the nucleus growth step (S20) was performed. Pure water, a 25% NaOH solution, and a 9% NH4OH solution were supplied as initial reactants for the nucleus growth step (S20). Pure water was supplied so as to satisfy a numerical range of 11,720 kg to 17,580 kg, the 25% NaOH solution so as to satisfy a numerical range of 3,866.4 kg to 5,799.6 kg, and the 9% NH4OH solution so as to satisfy a numerical range of 343.2 kg to 514.8 kg, and within the above numerical ranges, the total amount of the initial reactants was supplied so as to have a liquid level of 25% of the height of the second reactor.

[0069] Afterwards, 2.4 M NCM solution, 25% NaOH solution, and 9% NH4OH solution were introduced into the second reactor, and the flow rate of 2.4 M NCM solution was controlled from 2,725.6 kg / hr to 4,088.4 kg / hr, the flow rate of 25% NaOH solution was controlled from 1,536 kg / hr to 2,304 kg / hr, and the flow rate of 9% NH4OH solution was controlled from 239.2 kg / hr to 358.8 kg / hr. The average particle size of the formed nuclei D 50 In order to make the particle size close to the target value of 10.2 μm, the above solutions were fed for 48 hours. While the nucleus growth step (S20) was performed, the temperature of the solution in the second reactor was maintained at 40 to 60 °C. In order for the solution in the second reactor to have a pH value of 9.1 to 13.7, the input flow rate of the 25% NaOH solution was controlled within a range of 2% of the supply flow rate, the input flow rate of the 9% NH4OH solution was controlled within a range of 16% of the supply flow rate, and the 2.4 M NCM solution was controlled to be maintained. At this time, the pH value of the solution is a value measured based on 25 °C, not the process temperature (i.e., 40 to 60 °C). In order to remove dissolved oxygen in the solution, nitrogen gas was fed through the supply pipe at 600 Nm 3 / hr was injected. The rotation speed of the mixing shaft in the second reactor was set to 86 rpm when the reaction between the reactants began, and was then gradually reduced to 27 rpm when the reaction ended.

[0070] For the precursor particles formed through the above nucleation step (S10) and nucleus growth step (S20), a washing and drying step (S30) was performed. Specifically, the Na remaining in the coprecipitation solution was washed by supplying pure water three times, each for 10 to 15 minutes, to a filter press under conditions of 4.8 MPa to 7.2 MPa. Thereafter, air blowing was performed three times, each for 10 to 15 minutes, to reduce the moisture content within the NCM precursor.

[0071] [Example 2]

[0072] Unlike Example 1, the nucleation step (S10) has a capacity of 9 m 3 The first reactor was used. As the capacity of the first reactor was changed, the initial reactant supply amount was changed differently from Example 1, and specifically, pure water was supplied so as to satisfy the numerical range of 2,570.4 kg to 3,855.6 kg, the 25% NaOH solution so as to satisfy the numerical range of 20 kg to 30 kg, and the 9% NH4OH solution so as to satisfy the numerical range of 110.4 kg to 165.6 kg. In addition, the flow rates of the introduced reactants were also changed, and specifically, the flow rate of the 2.4 M NCM solution was supplied so as to satisfy the numerical range of 951.6 kg / hr to 1,427.4 kg / hr, the flow rate of the 25% NaOH solution so as to satisfy the numerical range of 540 kg / hr to 810 kg / hr, and the flow rate of the 9% NH4OH solution so as to satisfy the numerical range of 67.2 kg / hr to 100.8 kg / hr. Other process conditions were controlled in the same manner as in Example 1.

[0073] [Example 3]

[0074] Unlike Example 1, the nuclear growth stage (S20) has a capacity of 55 m 3The second reactor was used. As the capacity of the second reactor was changed, the initial reactant supply amount was changed differently from Example 1, and specifically, pure water was supplied to satisfy the numerical range of 19,531 kg to 29,297 kg, the 25% NaOH solution to satisfy the numerical range of 6,443.4 kg to 9,665 kg, and the 9% NH4OH solution to satisfy the numerical range of 572 kg to 858 kg. In addition, the flow rates of the introduced reactants were also changed, and specifically, the flow rate of the 2.4 M NCM solution was supplied to satisfy the numerical range of 4,542.6 kg / hr to 6,813.8 kg / hr, the flow rate of the 25% NaOH solution to satisfy the numerical range of 2,559 kg / hr to 3,838.6 kg / hr, and the flow rate of the 9% NH4OH solution to satisfy the numerical range of 398.6 kg / hr to 598 kg / hr. Other process conditions were controlled in the same manner as in Example 1.

[0075] [Example 4]

[0076] In Example 4, as in Example 2, the nucleation step (S10) was performed with a capacity of 9 m 3 In the first reactor, the initial reactant supply amount and the flow rate of the reactant were set to the same standard as the nucleus generation step (S10) of Example 2. In addition, in Example 4, as in Example 3, the nucleus growth step (S20) was performed with a capacity of 55 m 3 The second reactor was used. Accordingly, the initial reactant supply amount and the flow rate of the reactant input were set to the same standards as the nuclear growth step (S20) of Example 3. Other process conditions were controlled in the same way as in Example 1.

[0077] [Comparative example]

[0078] In the comparative example, 11m 3Nucleation and nucleus growth were performed in a single reactor of the same capacity. For nucleation, the same conditions as the nucleus generation step (S10) of Example 1 were applied, except for the conditions related to the reactor capacity. For nucleus growth, in addition to the conditions related to the reactor capacity, unlike Example 1, the process of supplying the initial reactants was omitted, and the reactants were introduced so that the flow rate of the 2.4 M NCM solution satisfied the numerical ranges of 908 kg / hr to 1,363.2 kg / hr, the flow rate of the 25% NaOH solution satisfied the numerical ranges of 512 kg / hr to 768 kg / hr, and the flow rate of the 9% NH4OH solution satisfied the numerical ranges of 79.8 kg / hr to 120 kg / hr.

[0079] The particle size, specific surface area, and density of the precursor particles in Examples 1 to 4 and Comparative Examples to which the above process conditions were applied are as shown in Table 1 below.

[0080] Item Unit Example 1 Example 2 Example 3 Example 4 Comparative Example Analysis D min μm0.40.40.40.40.40.4D 10 7.77.77.87.77.6D 50 109.810.11010.1D 90 12.712.212.312.312.6D max 17.21616.216.516.4Span0.50.470.520.510.53Specific surface areaBETm 2 / g9.59.49.79.69.6DensityTapDensityg / cm 3 22.022.082.052.1

[0081] Referring to Table 1, D 50 D represents the average particle diameter of silver particles, and examples 1 to 4 all have a D of about 10. 50 has a value, which is D in the comparative example 50 It is close to 10.1. Also, D 50 In addition, D min , D 10 , D 90 and D maxWith respect to values, the examples have values ​​close to those of the comparative examples. Accordingly, the span value, which is defined by Equation 1 below and indicates the uniformity of particle size, also has values ​​close to those of the examples and the comparative examples.

[0082] [Formula 1]

[0083] Span = (particle diameter D) 90 - Particle diameter D 10 ) / average particle diameter D 50

[0084] Furthermore, it can be confirmed that the examples have values ​​similar to those of the comparative examples in terms of the specific surface area and density of the precursor.

[0085] While the present invention has been described in connection with certain embodiments herein, it should be understood that various modifications and variations can be made without departing from the spirit and scope of the invention, as understood by those skilled in the art. Furthermore, such modifications and variations are intended to fall within the scope of the claims appended to this specification.

Claims

1. A method for manufacturing a positive electrode active material precursor, A nucleation step for forming nuclei of the precursor in the first reactor; and Including a nucleus growth step of growing the nucleus formed in the above production step in a second reactor, A method for producing a positive electrode active material precursor, wherein the capacity of the second reactor is greater than the capacity of the first reactor.

2. In paragraph 1, A method for producing a positive electrode active material precursor, wherein the capacity of the second reactor is 3.7 to 9.2 times the capacity of the first reactor.

3. In paragraph 1, The capacity of the above second reactor is 33 m 3 55m inland 3 A method for producing a precursor of a positive electrode active material.

4. In paragraph 1, A method for manufacturing a positive electrode active material precursor, wherein the progress time of the above nucleus generation step is shorter than the progress time of the above nucleus growth step.

5. In paragraph 1, The first reactor comprises a plurality of first reactors, and the nucleation step is performed in each of the plurality of first reactors, A method for producing a positive electrode active material precursor, wherein, in the above-mentioned nucleus growth step, nuclei formed from each of the plurality of first reactors grow together in the second reactor.

6. In paragraph 5, A method for producing a positive electrode active material precursor, wherein each of the nucleation steps performed in the plurality of first reactors is performed simultaneously with each other.

7. In paragraph 5, A method for producing a positive electrode active material precursor, wherein each of the nucleation steps performed in the plurality of first reactors is performed non-simultaneously with each other.

8. In paragraph 1, The above nucleation steps are: A first nucleation step for forming nuclei of the precursor in the first reactor; and comprising a second nucleation step for further forming nuclei of the precursor in the first reactor after completion of the first nucleation step; A method for producing a positive electrode active material precursor, wherein at least a portion of the second nucleus generation step is performed during a nucleus growth step for growing nuclei formed in the first nucleus generation step.

9. In paragraph 1, The above nucleation steps are: A first nucleation step for forming nuclei of the precursor in the first reactor; and comprising a second nucleation step for further forming nuclei of the precursor in the first reactor after completion of the first nucleation step; A method for producing a positive electrode active material precursor, wherein, in the above-mentioned nucleus growth step, nuclei formed in the above-mentioned first nucleus generation step and nuclei formed in the above-mentioned second nucleus generation step grow simultaneously.

10. In paragraph 1, Further comprising a storage step of storing the nuclei formed in the above nucleus generation step in a storage tank, A method for producing a positive electrode active material precursor, wherein, in the above-mentioned nucleus growth step, the nuclei stored in the above-mentioned storage step grow in the above-mentioned second reactor.

11. In paragraph 10, A method for producing a positive electrode active material precursor, wherein in the above storage step, the nucleus is stored at 40°C to 60°C.

12. In paragraph 10, A method for producing a positive electrode active material precursor, wherein in the above storage step, the nucleus is stored under pH 9.1 to pH 13.

7.

13. In paragraph 10, A method for producing a positive electrode active material precursor, wherein the above storage step is performed for 48 hours or less.

14. In paragraph 1, The above nucleation step comprises supplying initial reactants to the first reactor, A method for producing a positive electrode active material precursor, wherein the initial reactant is supplied such that the liquid level of the initial reactant is 20% to 30% of the height of the first reactor.

15. In paragraph 1, The above nuclear growth step comprises supplying initial reactants to the second reactor, A method for producing a positive electrode active material precursor, wherein the initial reactant is supplied such that the liquid level of the initial reactant is 20% to 30% of the height of the second reactor.

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