Apparatus and method for preparing a precursor

Abstract

The invention relates to an apparatus and a method for preparing a precursor. The apparatus for preparing a precursor according to the present invention is an apparatus for preparing a precursor by subjecting a raw material to a co-precipitation reaction, the apparatus comprising: a co-precipitation reaction tank in which an accommodation material containing a reactant and a remainder is accommodated; and a pH measurement system that measures the pH of the remainder, in which the pH measurement system includes: a filter that is provided inside the coprecipitation reaction tank and filters the remainder from the accommodating material; and a pH measurement unit provided outside the co-precipitation reaction tank to measure the pH of the residue filtered by the filter.

Description

Technical Field

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to Korean Patent Application Nos. 10-2022-0063154, filed on May 24, 2022, and 10-2023-0066005, filed on May 23, 2023, which are hereby incorporated by reference in their entirety. Technical Field

[0003] The present invention relates to an apparatus and a method for preparing a precursor. Background Art

[0004] As the technology of mobile devices develops and the demand increases, the demand for secondary batteries as energy sources is rapidly increasing. Among secondary batteries, lithium secondary batteries with high energy density, high discharge voltage, long cycle life and low self-discharge rate are commercialized and widely used.

[0005] Lithium transition metal oxides are used as positive electrode active materials for lithium secondary batteries. Among lithium transition metal oxides, LiCoO2, which is lithium cobalt oxide, is mainly used because it has high operating voltage and excellent capacity characteristics. However, because LiCoO2 has very poor thermal characteristics due to the instability of the crystal structure caused by delithiation and is very expensive, there are problems in using a large amount of LiCoO2 as a power source in fields such as electric vehicles.

[0006] Lithium manganese oxide (LiMnO2, LiMn2O4, etc.), lithium iron phosphate compounds (LiFePO4, etc.), lithium nickel oxide (LiNiO2, etc.), etc. are developed as materials for replacing LiCoO2. Among these materials, research and development of lithium nickel oxide having a high reversible capacity of about 200 mAh / g to easily realize a battery with a large capacity is more actively carried out. However, compared with LiCoO2, LiNiO2 has poor thermal stability and has the following problems: when an internal short circuit occurs due to pressure from the outside, etc. in a charged state, the positive electrode active material itself decomposes to cause explosion and ignition of the battery.

[0007] Therefore, LiNi in which part of nickel is replaced by cobalt has been developed. 1-α Co α O2 (α = 0.1-0.3) or nickel-cobalt-manganese (NCM) lithium composite metal oxides in which part of the nickel is replaced by Mn and Co are used as technical solutions to maintain excellent reversible capacity and improve the low thermal stability of LiNiO2. In addition, lithium transition metal oxides with a concentration gradient of metal composition are proposed to achieve excellent output characteristics and solve stability problems caused by the elution of metal elements, etc.

[0008] When the NCM precursor to which the existing coprecipitation reaction is applied is prepared according to the related art, the pH is controlled to prepare the precursor in which the particle growth, primary particle growth and sphericity are controlled. In the preparation of the precursor, the pH is a parameter that must be managed to improve the performance of the positive electrode material, for example, as the effect of improving the uniformity of sintering and particle strength when the positive electrode material is sintered, the battery performance, such as cycle life and gas generation, is improved.

[0009] However, in reality, due to the lack of durability of the pH sensor and the lack of reliability of the pH value in the reactor, sampling is performed manually and the pH is managed using an external pH sensor, so the redundancy and fatigue of the work increase. In addition, since the reliability of the internally installed pH sensor is not enough for repeated use, the pH sensor is discarded after a single use, or is likely to have cracks and contact defects during the reaction, which leads to defects in the precursor. Summary of the invention

[0010] Technical issues

[0011] One aspect of the present invention is to provide an apparatus and method for preparing a precursor that can improve the reliability of pH analysis.

[0012] Technical Solution

[0013] The device for preparing a precursor according to one embodiment of the present invention is a device for preparing a precursor by subjecting raw materials to a coprecipitation reaction to prepare the precursor, the device comprising:

[0014] a coprecipitation reaction tank in which a containing material including a reactant and a remainder is contained; and

[0015] a pH measuring system for measuring the pH of the residue,

[0016] The pH measurement system comprises:

[0017] a filter which is disposed inside the coprecipitation reaction tank and filters the remainder from the containing material; and

[0018] A pH measuring part is provided outside the coprecipitation reaction tank to measure the pH of the residue filtered through the filter.

[0019] A method for preparing a precursor according to one embodiment of the present invention is a method for preparing a precursor by subjecting raw materials to a coprecipitation reaction to prepare the precursor, the method comprising:

[0020] A containing step: containing raw materials in a coprecipitation reaction tank, wherein the raw materials form a containing material including a reactant and a residue; and

[0021] pH measurement step: measuring the pH of the residue,

[0022] The pH measurement process comprises:

[0023] Filtration step: filtering the residue from the containing material through a filter disposed inside the coprecipitation reaction tank; and

[0024] Measuring process: The pH of the residue filtered through the filter is measured by a pH measuring unit provided outside the coprecipitation reaction tank.

[0025] Beneficial Effects

[0026] According to the present invention, in a pH measuring system of an apparatus for preparing a precursor applied to preparing a precursor by a co-precipitation reaction, the pH measuring part can be configured to be able to measure the pH outside the co-precipitation reaction tank, so as to prevent the pH sensor for measuring the pH from breaking, thereby improving the analysis reliability and reducing the cost of the pH sensor breaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a front view showing an apparatus for preparing a precursor according to one embodiment of the present invention.

[0028] Figure 2 is a front view showing a pH measuring system in an apparatus for preparing a precursor according to one embodiment of the present invention.

[0029] Figure 3 : is a front view showing a pH measuring part in a pH measuring system of an apparatus for preparing a precursor according to one embodiment of the present invention. DETAILED DESCRIPTION

[0030] The above and other aspects, features and other advantages of the present invention will be more clearly understood through the following detailed description and preferred embodiments in conjunction with the accompanying drawings. Note that even if the same elements are shown in different drawings, they are represented by the same reference numerals as much as possible. The present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. In addition, detailed descriptions related to known techniques will be excluded to avoid unnecessarily obscuring the subject matter of the present invention.

[0031] Device for preparing a precursor according to one embodiment

[0032] Figure 1 is a front view showing an apparatus for preparing a precursor according to one embodiment of the present invention. Figure 2 is a front view showing a pH measuring system in an apparatus for preparing a precursor according to one embodiment of the present invention. Figure 3: is a front view showing a pH measuring part in a pH measuring system of an apparatus for preparing a precursor according to one embodiment of the present invention. Here, Figures 1 to 3 This is a reference view looking through the interior of the device. Figure 2 Shows Figure 1 The enlarged area A in Figure 3 Shows Figure 1 The enlarged area B in .

[0033] Reference Figures 1 to 3 , an apparatus 1000 for preparing a precursor according to an embodiment of the present invention is an apparatus 1000 for preparing a precursor by subjecting a raw material to a coprecipitation reaction to prepare a precursor. The apparatus 1000 for preparing a precursor includes a coprecipitation reaction tank 200 containing a containing material including a reactant and a residue and a pH measuring system 100 for measuring the hydrogen ion concentration (pH) of the residue. The pH measuring system 100 includes a filter 120 for filtering the residue and a pH measuring part 110 for measuring the pH of the residue. In the apparatus 1000 for preparing a precursor according to an embodiment of the present invention, the pH measuring system 100 may further include a connecting pipe P connected to the pH measuring part 110 and a residue moving pump 130 for moving the residue. The apparatus 1000 for preparing a precursor according to an embodiment of the present invention may further include an agitator 300, a heater 400, a raw material inlet 500, a reactant outlet 600, and a main filter 700.

[0034] In more detail, a receiving part 200 a receiving a receiving material including a reactant and a residue is defined in the coprecipitation reaction tank 200 .

[0035] The coprecipitation reaction tank 200 is provided in a tank shape, for example, may be provided in a cylindrical shape.

[0036] The agitator 300 may agitate the raw materials contained inside the coprecipitation reaction tank 200 .

[0037] In addition, the agitator 300 may include a rotating part 310 provided inside the coprecipitation reaction tank 200 to rotate, and a motor part 320 to rotate the rotating part 310. Here, the rotating part 310 may rotate inside the coprecipitation reaction tank 200 and rotate and stir the raw material.

[0038] The heater 400 may apply heat to the raw material contained inside the coprecipitation reaction tank 200 .

[0039] Here, the heater 400 may increase the temperature of the raw material to accelerate the coprecipitation reaction. For example, the heater 400 may heat the raw material to a temperature of about 50°C.

[0040] For example, the heater 400 may be disposed on a side wall of the co-precipitation reaction tank 200 .

[0041] The raw material inlet 500 may be connected to the upper portion of the coprecipitation reaction tank 200 to introduce a raw material into the coprecipitation reaction tank 200. That is, the raw material as a reaction material may be supplied to the receiving part 200a of the coprecipitation reaction tank 200 through the raw material inlet 500.

[0042] The raw material may include a metal solution, a caustic soda solution and aqueous ammonia. Here, for example, the metal solution may be a nickel-cobalt-manganese (Ni-Co-Mn) solution, and the caustic soda may be NaOH. In addition, the caustic soda may be a pH adjusting material, and aqueous ammonia may be a coagulant. Here, the input of caustic soda may be adjusted according to the pH level of the residue measured by the pH measurement system 100 to adjust the pH of the contained material contained in the containing portion 200a of the coprecipitation reaction tank 200. For example, the pH of the contained material contained in the containing portion 200a of the coprecipitation reaction tank 200 may be adjusted so that the pH of the residue is 10-12, and particles may be grown to prepare a precursor.

[0043] The reactant outlet 600 may be connected to the lower portion of the coprecipitation reaction tank 200 to discharge the completely reacted reactant disposed inside the coprecipitation reaction tank 200. That is, the prepared precursor as the reactant may be discharged from the lower portion of the coprecipitation reaction tank 200 through the reactant outlet 600. Here, the precursor may be provided as an NCM (nickel / cobalt / manganese) precursor for a positive electrode active material.

[0044] Additionally, the reactant outlet 600 may include a reactant discharge valve 610 to regulate the discharge of the reactants.

[0045] The main filter 700 may filter the reaction solution disposed inside the coprecipitation reaction tank 200. Here, the precursor reaction and the filtration flow rate may be confirmed while a portion of the reaction solution disposed inside the coprecipitation reaction tank 200 is discharged to the outside of the coprecipitation reaction tank 200 after being filtered by the main filter 700.

[0046] The pH measuring system 100 may measure the pH of the residue contained inside the coprecipitation reaction tank 200. Here, the pH measuring system 100 may include a filter 120, a pH measuring part 110, a connection pipe P, and a residue moving pump 130.

[0047] The filter 120 can be arranged inside the coprecipitation reaction tank 200 and filter the residue from the containing material. That is, when the raw material arranged inside the coprecipitation reaction tank 200 produces the reactant and residue as the containing material by the coprecipitation reaction, the filter 120 can filter the residue from the containing material. Here, in the metal solution as the raw material, the metal as the reactant can be precipitated, and other can be generated as the residue by the coprecipitation reaction. Here, as an example, the residue can include water (H2O). As another example, the residue can include water (H2O), ammonia, Na2SO4, etc.

[0048] The filter 120 may be provided as a metal filter made of a metal material. Therefore, the filter 120 may be prevented from being broken when colliding with the containing material contained inside the coprecipitation reaction tank 200. In addition, the filter 120 may be prevented from being chemically damaged by the liquid containing material contained inside the coprecipitation reaction tank 200. Here, the filter 120 may be made of, for example, a stainless steel material.

[0049] The pH measuring system 100 may include a pH measuring part 110 disposed outside the coprecipitation reaction tank 200 to measure the pH of the residue filtered by the filter 120. Here, the pH measuring part 110 may include a buffer tank 111, a pH sensor 112, a fixing part 113, a water level sensor 115, a clean water inlet 116, and a clean water outlet 117.

[0050] The buffer tank 111 may be connected to the connection pipe P to accommodate the residue filtered by the filter 120. In addition, an accommodation space 111a for accommodating the residue may be defined inside the buffer tank.

[0051] The pH sensor 112 may measure the pH of the remainder contained in the buffer tank 111 .

[0052] The fixing portion 113 may fix the pH sensor 112 to the buffer tank 111. Here, the fixing portion 113 may be provided at an upper portion of the buffer tank to fix the pH sensor 112. In addition, the fixing portion 113 may have a through hole 113a defined therein and passed through by the pH sensor 112, and may include a rubber packing 114 provided between the through hole 113a and the pH sensor 112, so that the pH sensor 112 is press-fitted with the fixing portion 113 and coupled to the fixing portion 113.

[0053] The water level sensor 115 may measure a water level L1 of the remainder contained in the buffer tank 111 and a water level L2 of the clean water.

[0054] The clean water inlet 116 may be connected to the upper portion of the side surface of the buffer tank 111 to introduce clean water into the buffer tank 111. Therefore, the inside of the buffer tank 111 may be cleaned with clean water so that the pH of the residue introduced into the buffer tank 111 for pH measurement after cleaning is accurately measured.

[0055] The clean water inlet 116 may introduce clean water into the buffer tank 111 such that a water level L2 of the clean water is higher than a water level L1 of the residues that have been introduced into the buffer tank 111. Therefore, the residues remaining inside the buffer tank may be completely cleaned.

[0056] In addition, the cleaning water introduced through the cleaning water inlet 116 may be a neutralized liquid having a pH of 7 to 8. The cleaning water may also include water.

[0057] The clean water outlet 117 may be connected to the lower portion of the buffer tank 111 to discharge the clean water introduced into the buffer tank 111. Here, the clean water outlet 117 may discharge the residue contained in the buffer tank 111 before the inside of the buffer tank 111 is cleaned. The clean water outlet 117 may include a clean water discharge valve 118 that regulates the discharge of the clean water or residue contained inside the buffer tank 111.

[0058] The connection pipe P may have one side portion disposed inside the coprecipitation reaction tank 200 to be connected to the filter 120 , and the other side portion extending to the outside of the coprecipitation reaction tank 200 to be connected to the pH measuring part 110 .

[0059] A residue moving pump 130 may be provided on the connection pipe P to move the residue from the filter 120 to the buffer tank 111 .

[0060] Therefore, when the device 1000 for preparing a precursor according to one embodiment of the present invention configured as above prepares a precursor through a co-precipitation reaction, the pH measuring unit 110 can be configured in the pH measurement system 100 to be able to measure the pH outside the co-precipitation reaction tank 200, so as to prevent the pH sensor 112 for measuring the pH from rupturing, thereby improving the analysis reliability and reducing the rupture cost of the pH sensor 112.

[0061] A method for preparing a precursor according to an embodiment

[0062] Hereinafter, a method for preparing a precursor according to one embodiment of the present invention will be described.

[0063] Reference Figures 1 to 3 According to one embodiment of the present invention, the method for preparing a precursor is to prepare a precursor by subjecting the raw materials to a coprecipitation reaction. The method for preparing a precursor may include:

[0064] Accommodation process: accommodating raw materials in the coprecipitation reaction tank 200, wherein the raw materials form a containing material including reactants and residues, and

[0065] pH measurement procedure: Measure the pH of the residue.

[0066] pH measurement procedures may include:

[0067] Filtration process: filtering the remainder from the contained material through the filter 120 provided inside the coprecipitation reaction tank 200, and

[0068] Measurement process: The pH of the residue filtered through the filter 120 is measured by a pH measuring part provided outside the coprecipitation reaction tank 200 .

[0069] The method for preparing a precursor according to one embodiment of the present invention is a method for preparing a precursor by the apparatus 1000 for preparing a precursor according to one embodiment of the present invention described above. Therefore, this embodiment of the method for preparing a precursor will be described by omitting or simply describing the contents repeated with the embodiment of the apparatus 1000 for preparing a precursor described above, and focusing on the differences.

[0070] In more detail, in the containing process, raw materials forming a containing material including a reactant and a residue are contained in the containing part 200 a of the coprecipitation reaction tank 200 .

[0071] Additionally, the containment process may include:

[0072] Raw material introduction process: the raw material is introduced into the coprecipitation reaction tank 200 through the raw material inlet 500 connected to the upper portion of the coprecipitation reaction tank 200 .

[0073] Here, in the raw material introduction process, a raw material as a reaction material may be supplied to the accommodation part 200 a of the coprecipitation reaction tank 200 through the raw material inlet 500 .

[0074] In addition, the raw material introduced into the coprecipitation reaction tank 200 through the raw material introduction process may be a containing material including a reactant and a remainder in the coprecipitation reaction tank 200 .

[0075] Here, in the containing process, a raw material is introduced into the coprecipitation reaction tank 200 , and the introduced raw material reacts in the coprecipitation reaction tank 200 to form a contained material including a reactant and a residue, so that the contained material is contained in the coprecipitation reaction tank 200 .

[0076] The raw materials may include a metal solution, a caustic soda solution, and aqueous ammonia. Here, for example, the metal solution may be a nickel-cobalt-manganese (Ni-Co-Mn) solution, and the caustic soda may be NaOH. In addition, the caustic soda may be a pH adjusting material, and the aqueous ammonia may be a coagulant.

[0077] In the stirring process, the raw material contained inside the coprecipitation reaction tank 200 may be stirred by a stirrer after the containing process. More specifically, the stirring process may be performed after the raw material is introduced into the coprecipitation reaction tank 200 through the raw material introducing process in the containing process.

[0078] Here, the agitator 300 may include a rotating part 310 provided inside the coprecipitation reaction tank 200 to rotate, and a motor part 320 to rotate the rotating part 310. Here, the rotating part 310 may rotate inside the coprecipitation reaction tank 200 and rotate and agitate the raw material.

[0079] In the heating process, heat may be applied to the raw material contained inside the coprecipitation reaction tank 200 by a heater during the stirring process or before and during the stirring process.

[0080] In the heating process, the temperature of the raw material may be increased to accelerate the coprecipitation reaction by the heater 400. In the heating process, for example, the heater 400 may heat the raw material to a temperature of about 50°C.

[0081] For example, the heater 400 may be disposed on a side wall of the co-precipitation reaction tank 200 .

[0082] The pH measurement process may include a filtering process and a measuring process, and the pH of the residue may be measured by the pH measurement system 100. Here, the pH measurement system 100 may include a filter 120, a pH measuring part 110, a connection pipe P, and a residue moving pump 130.

[0083] The pH measurement process may be performed after the accommodation process. Specifically, the pH measurement process may be performed after the raw material is introduced into the coprecipitation reaction tank 200 through the raw material introduction process in the accommodation process.

[0084] Here, for example, the pH measurement process may be performed in one or more of a process before the stirring process, a process during the stirring process, and a process after the stirring process.

[0085] In the filtering process, the remainder may be filtered from the contained material through the filter 120 provided inside the coprecipitation reaction tank 200 .

[0086] In addition, in the filtering process, the filter 120 can be arranged inside the coprecipitation reaction tank 200 to filter the residue from the containing material. That is, when the raw material arranged inside the coprecipitation reaction tank 200 produces the reactant and residue as the containing material by the coprecipitation reaction, the filter 120 can filter the residue from the containing material. Here, in the metal solution as the raw material, the metal as the reactant can be precipitated, and other can be generated as the residue by the coprecipitation reaction. Here, as an example, the residue can include water (H2O). As another example, the residue can include water (H2O), ammonia, Na2SO4, etc.

[0087] The filter 120 may be provided as a metal filter made of a metal material. Therefore, the filter 120 may be prevented from being broken when colliding with the containing material contained inside the coprecipitation reaction tank 200. In addition, the filter 120 may be prevented from being chemically damaged by the liquid containing material contained inside the coprecipitation reaction tank 200. Here, the filter 120 may be made of, for example, a stainless steel material.

[0088] In the measurement process, the pH of the residue filtered by the filter 120 can be measured by the pH measuring part 110 provided outside the coprecipitation reaction tank 200. In addition, the measurement process may include a residue receiving process and a sensor measurement process. The measurement process may also include a clean water introduction process and a clean water discharge process.

[0089] In the residue accommodation process, the residue filtered through the filter 120 may be accommodated in the buffer tank 111 through the connection pipe P having one side connected to the filter 120 and the other side connected to the pH measuring part 110. Here, in the residue accommodation process, the residue may be moved from the filter 120 to the buffer tank 111 by the residue moving pump 130 provided on the connection pipe P. The buffer tank 111 may be connected to the connection pipe P to accommodate the residue filtered through the filter 120. In addition, an accommodation space 111a for accommodating the residue may be defined inside the buffer tank 111.

[0090] In the sensor measurement process, the pH of the remainder contained in the buffer tank 111 may be measured by the pH sensor 112 of the pH measuring part 110 .

[0091] In the clean water introduction process, when the residue contained in the buffer tank 111 is discharged after the sensor measurement process, clean water may be introduced into the buffer tank through the clean water inlet connected to the upper portion of the side surface of the buffer tank to clean the inside of the buffer tank. Here, the clean water outlet 117 may discharge the residue contained in the buffer tank 111 before the inside of the buffer tank 111 is cleaned.

[0092] Therefore, the inside of the buffer tank 111 may be cleaned using the clean water so that the pH of the remainder introduced into the buffer tank 111 for pH measurement after the cleaning is accurately measured.

[0093] In addition, in the cleaning water introduction process, the cleaning water introduced through the cleaning water inlet 116 may be a neutralized liquid having a pH of 7 to 8. The cleaning water may also include water.

[0094] In the clean water introducing process, the clean water may be introduced such that the water level of the clean water is higher than the water level of the remainder that has been introduced into the buffer tank through the remainder introducing process.

[0095] In the clean water introduction process, the water level L1 of the residue contained in the buffer tank 111 and the water level L2 of the clean water can be measured by the water level sensor 115 to make the water level of the clean water higher. The water level L2 of the clean water can be adjusted to be higher than the water level L1 of the residue contained in the buffer tank 111.

[0096] In the clean water discharge process, the clean water introduced into the buffer tank 111 may be discharged through the clean water outlet 117 connected to the lower portion of the buffer tank 111 .

[0097] The method for preparing a precursor according to one embodiment of the present invention may further include:

[0098] pH adjustment process: input of caustic soda is adjusted according to the pH level of the residue measured by the pH measurement process to adjust the pH of the contained material contained in the containing part 200 a of the coprecipitation reaction tank 200 .

[0099] In the pH adjustment process, the pH of the contained material contained in the containing part 200a of the coprecipitation reaction tank 200 may be adjusted so that the pH of the remainder is 10-12.

[0100] In addition, in the method for preparing a precursor according to one embodiment of the present invention, the pH of the residue can be effectively adjusted while the pH measurement process and the pH adjustment process are repeated. Here, for example, the pH measurement process and the pH adjustment process can be performed in one or more processes of the process before the stirring process, the process during the stirring process, and the process after the stirring process.

[0101] The method for preparing a precursor according to one embodiment of the present invention may further include:

[0102] Reaction solution filtering step: The reaction solution disposed inside the coprecipitation reaction tank 200 is filtered through the main filter 700 .

[0103] In the reaction solution filtering process, the precursor reaction and the filtering flow rate can be confirmed, and a part of the reaction solution disposed inside the coprecipitation reaction tank 200 is discharged to the outside of the coprecipitation reaction tank 200 after being filtered through the main filter 700 .

[0104] Although the present invention has been described in detail with reference to limited embodiments, the present invention is not limited thereto. Within the technical concept of the present invention, the present invention can be variously implemented by a person skilled in the art to which the present invention belongs.

[0105] Furthermore, the specific protection scope of the present invention will be set forth by the claims.

[0106] [Explanation of Reference Numerals]

[0107] 100: pH measurement system

[0108] 110: pH measurement unit

[0109] 111: Buffer tank

[0110] 111a: Accommodation Space

[0111] 112: pH sensor

[0112] 113: Fixed part

[0113] 113a: Through hole

[0114] 114: Rubber filler

[0115] 115: Water level sensor

[0116] 116: Clean water inlet

[0117] 117: Clean water outlet

[0118] 118: Clean water discharge valve

[0119] 120: Filter

[0120] 130: Residue removal pump

[0121] 200: Co-precipitation reaction tank

[0122] 200a: Accommodation

[0123] 300: Blender

[0124] 400: Heater

[0125] 500: Raw material entrance

[0126] 600: Reactant outlet

[0127] 700: Main filter

[0128] 1000: Apparatus for preparing precursors

[0129] P: Connecting pipe

Claims

1. A device for preparing a precursor configured to subject a raw material to a coprecipitation reaction to prepare a precursor, the device include: a coprecipitation reaction tank containing a containing material including reactants and a residue; and a pH measurement system configured to measure the pH of the residue, The pH measurement system comprises: a filter disposed inside the coprecipitation reaction tank and configured to filter the remainder from the containing material; and A pH measuring part is provided outside the coprecipitation reaction tank to measure the pH of the residue filtered through the filter.

2. The device according to claim 1, further comprising a connecting pipe, wherein the connecting pipe has: is disposed inside the coprecipitation reaction tank so as to be connected to one side of the filter, and The other side portion extends to the outside of the coprecipitation reaction tank to be connected to the pH measuring portion.

3. The device according to claim 2, wherein the pH measuring unit include: a buffer tank connected to the connecting pipe to accommodate a residue filtered by the filter; and A pH sensor is configured to measure the pH of the residue contained in the buffer tank. 4 . The apparatus according to claim 3 , wherein the pH sensor vertically passes through the buffer tank and has a lower portion disposed inside the buffer tank. 5 . The device according to claim 4 , wherein the pH measuring part further comprises a fixing part configured to fix the pH sensor to the buffer tank.

6. The device according to claim 5, in, The fixing portion has a through hole defined therein and through which the pH sensor passes, and The fixing portion includes a rubber filler disposed between the through hole and the pH sensor, so that the pH sensor is press-fitted with the fixing portion and coupled to the fixing portion.

7. The apparatus according to claim 3, further comprising a residue moving pump provided on the connecting pipe to move the residue from the filter to the buffer tank.

8. The device according to claim 3, wherein the pH measuring unit further include: a clean water inlet connected to an upper portion of a side surface of the buffer tank to introduce clean water into the buffer tank; and A clean water outlet is connected to a lower portion of the buffer tank to discharge the clean water introduced into the buffer tank. 9 . The apparatus according to claim 8 , wherein the pH measuring part further comprises a water level sensor configured to measure a water level of each of the remainder and the clean water contained in the buffer tank.

10. The device according to claim 1, wherein the filter is provided as a metal filter.

11. The device according to claim 1, further comprising: include: an agitator configured to agitate the raw materials contained in the coprecipitation reaction tank; and A heater configured to apply heat to the raw material contained inside the coprecipitation reaction tank.

12. A method for preparing a precursor by subjecting raw materials to a coprecipitation reaction to prepare a precursor, the method include: A containing step: containing raw materials in a coprecipitation reaction tank, wherein the raw materials are configured to form a containing material including reactants and residues; and pH measurement step: measuring the pH of the residue, The pH measurement process comprises: Filtration step: filtering the residue from the containing material through a filter disposed inside the coprecipitation reaction tank; and Measuring process: The pH of the residue filtered through the filter is measured by a pH measuring unit provided outside the coprecipitation reaction tank.

13. The method according to claim 12, wherein the measuring step include: A residue accommodation process: accommodating the residue filtered through the filter in a buffer tank through a connecting pipe having one side connected to the filter and another side connected to the pH measuring part; and Sensor measurement process: The pH of the residue contained in the buffer tank is measured by the pH sensor of the pH measuring part.

14. The method according to claim 13, in, In the residue accommodation process, the residue is moved from the filter to the buffer tank by a residue moving pump provided on the connection pipe.

15. The method according to claim 13, wherein the measuring step include: a clean water introducing process of introducing clean water into the buffer tank through a clean water inlet connected to an upper portion of a side surface of the buffer tank to clean the inside of the buffer tank when the residue contained in the buffer tank is discharged after the sensor measuring process; and A clean water discharge process of discharging the clean water introduced into the buffer tank through a clean water outlet connected to a lower portion of the buffer tank.

16. The method according to claim 15, in, In the clean water introducing process, the clean water is introduced so that the water level of the clean water is higher than the water level of the residue that has been introduced into the buffer tank through the residue containing process.

17. The method according to claim 12, further comprising: include: Stirring step: after the containing step, stirring the raw materials contained in the coprecipitation reaction tank by a stirrer; and Heating process: during the stirring process or before and during the stirring process, heat is applied to the raw material contained inside the coprecipitation reaction tank by a heater.

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