A multi-chamber continuous reaction device

Abstract

This utility model relates to a multi-chamber continuous reaction device, comprising a primary reaction vessel, an intermediate control vessel, and a secondary reaction vessel connected in sequence. The primary reaction vessel includes a first vessel body, a first inlet, and a first outlet. The intermediate control vessel includes a second vessel body, a second inlet, and a second outlet, and an inlet / outlet is provided at the top of the second vessel body. The upper end of the inlet / outlet is connected to a pressure regulating pipeline provided outside the second vessel body, and the lower end of the inlet / outlet extends into the interior of the second vessel body. The secondary reaction vessel includes a third vessel body, a third inlet, and a third outlet. The multi-chamber continuous reaction device provided by this utility model can realize continuous multiple reactions and can perform positive and negative pressure treatment on the reaction materials, thereby controlling the growth morphology and size of the materials and improving the particle density and uniformity of the materials.

Description

Technical Field

[0001] This utility model relates to the field of reaction device technology, and in particular to a multi-chamber continuous reaction device. Background Technology

[0002] Lithium manganese iron phosphate (LiFePO4) has attracted much attention in recent years as a cathode material for lithium-ion batteries due to its high energy density, long cycle life, and good safety, making it particularly suitable for electric vehicles and large-scale energy storage systems. This material inherits the good safety of LiFePO4 and the high energy density of LiMnPO4, exhibiting significant advantages in theoretical capacity, voltage plateau, and cycle performance, thus possessing broad market prospects and competitiveness.

[0003] However, several key issues remain to be addressed in the practical application of LiFeMnPO4 materials: First, small primary particle size: The small particle size of LiFeMnPO4 materials results in a large specific surface area, making them prone to side reactions during charge and discharge, thus affecting the cycle stability and rate performance of the battery. Second, poor conductivity: The low electronic conductivity of the material limits its application under high-rate conditions, especially in fast charging and discharging scenarios. Third, large specific surface area: The large specific surface area increases the contact area between LiFeMnPO4 materials and the electrolyte, making them prone to interfacial side reactions during cycling, further accelerating capacity decay. Fourth, poor processing performance: Due to the small particle size and relatively loose structure, it is difficult to obtain good compaction density and consistency when preparing electrodes from LiFeMnPO4 materials, affecting the overall performance of the battery. These problems severely restrict the practical application of LiFeMnPO4 materials.

[0004] The preparation of lithium manganese iron phosphate materials usually involves a combination of multiple processes such as solid-phase or liquid-phase methods. Reactors are commonly used reaction devices for the preparation of precursors in the process of preparing battery cathode materials because they can meet the conditions of high temperature, high pressure, corrosion resistance and uniform mixing. The morphology and properties of precursor materials directly affect the morphology and properties of cathode materials.

[0005] The mainstream reaction apparatus for precursor materials is generally a single-reactor batch reactor or a two-reactor parallel reactor. However, single-reactor batch reactors have low capacity, making it difficult to meet the needs of large-scale production, while two-reactor reactors suffer from uneven particle size distribution, inaccurate element ratios, and poor batch-to-batch stability. Furthermore, the LiFeMnPO4 precursor materials prepared using existing reaction apparatus still exhibit small particle size and loose structure, as well as difficulties in achieving good tap density and poor consistency.

[0006] Therefore, developing a reaction device that can improve material properties and optimize material morphology has become an urgent problem to be solved. Utility Model Content

[0007] To address the aforementioned technical problems, the purpose of this invention is to provide a multi-chamber continuous reaction device. This multi-chamber continuous reaction device enables continuous, multiple reactions and allows for positive and negative pressure treatment of the reaction materials, thereby controlling the growth morphology and size of the materials and improving their particle density and uniformity.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] This utility model provides a multi-chamber continuous reaction device, which includes a primary reaction vessel, an intermediate control vessel, and a secondary reaction vessel connected in sequence.

[0010] The primary reactor includes a first reactor body, with a first inlet and a first outlet respectively disposed at the top and bottom of the first reactor body;

[0011] The intermediate regulating vessel includes a second vessel body, a second inlet and a second outlet respectively provided at the top and bottom of the second vessel body, and an air inlet and outlet provided at the top of the second vessel body. The upper end of the air inlet and outlet is connected to a pressure regulating pipeline provided outside the second vessel body, and the lower end of the air inlet and outlet extends into the interior of the second vessel body.

[0012] The secondary reactor includes a third vessel body, with a third inlet and a third outlet respectively located at the top and bottom of the third vessel body;

[0013] The first discharge port of the primary reactor is connected to the second inlet of the intermediate control vessel; the second discharge port of the intermediate control vessel is connected to the third inlet of the secondary reactor.

[0014] The following are preferred technical solutions of this utility model, but are not intended to limit the technical solutions provided by this utility model. Through the following preferred technical solutions, the purpose and beneficial effects of this utility model can be better achieved.

[0015] As a preferred technical solution of this utility model, a first stirring unit is provided inside the first reactor body in the first primary reactor.

[0016] In this invention, the stirring unit may include a motor, a stirring shaft, and a stirring paddle. The electrode is fixedly disposed at the center of the top of the vessel body. One end of the stirring shaft is connected to the output end of the electrode, and the other end of the stirring shaft extends into the interior of the vessel body. The stirring paddle is disposed on the outside of the stirring shaft.

[0017] In this invention, the number of first feed inlets at the top of the primary reactor can be selected according to the type and quantity of raw materials added, including but not limited to 1, 2, 3, 4 or 5, etc., which can be selected by those skilled in the art as needed.

[0018] As a preferred technical solution of this utility model, a concentration detector is also provided inside the second vessel body in the intermediate control vessel.

[0019] As a preferred technical solution of this utility model, a second stirring unit is provided inside the second vessel.

[0020] Preferably, the concentration tester and the second stirring unit are spaced apart.

[0021] Preferably, a fourth feed inlet is also provided at the top of the second vessel.

[0022] As a preferred technical solution of this utility model, a gas buffer is provided at the lower end of the gas inlet and outlet in the intermediate regulating vessel.

[0023] Preferably, the gas buffer has a porous rod-shaped structure.

[0024] Preferably, the gas buffer is disposed inside the second vessel body of the intermediate control vessel.

[0025] In this invention, a gas buffer is installed at the lower end of the inlet and outlet of the intermediate control vessel. This can prevent the slurry inside the vessel from being drawn out of the intermediate control vessel when the depressurization speed is too fast, thereby avoiding material loss and damage to the pressure regulating pipeline. At the same time, it can prevent the gas from being sprayed directly onto the liquid surface and causing slurry splashing due to the excessively fast gas pressurization speed. This also prevents the splashed slurry from adhering to the vessel wall, allowing the material to react fully and improving the consistency of the product in the subsequent reaction process.

[0026] Preferably, the gas buffer is made of either a polymer material or a ceramic material.

[0027] Preferably, the polymeric material includes polyethylene and / or polyamide.

[0028] As a preferred technical solution of this utility model, a three-way valve is provided on the pressure regulating pipeline.

[0029] In this invention, a three-way valve is installed on the pressure regulating pipeline. When pressurizing, gas can be injected into the body of the intermediate regulating vessel. When depressurizing (gas extraction to form a certain degree of vacuum), gas can be extracted and transported to subsequent equipment for gas recovery.

[0030] As a preferred technical solution of this utility model, the multi-chamber continuous reaction device is further provided with an ammonia stripping device, which is connected to the upper end of the pressure regulating pipeline.

[0031] In the preparation of LiFeMnPO4 precursor materials, the raw materials for the reaction will introduce ammonium compounds. During the positive and negative pressure treatment of the reaction materials in the intermediate control vessel, the gas extracted during the depressurization process will contain a certain amount of ammonia in addition to the nitrogen or inert gas introduced during the pressurization. The ammonia in the waste gas can enter the ammonia stripping equipment connected to the pressure regulating pipeline through the pressure regulating pipeline to realize the recycling of ammonia.

[0032] As a preferred technical solution of this utility model, a third stirring unit is provided inside the third vessel body in the secondary reaction vessel.

[0033] As a preferred embodiment of this invention, a fifth feed inlet is also provided at the top of the secondary reactor.

[0034] In this invention, the number of fifth feed inlets at the top of the secondary reactor can be selected according to the type and quantity of raw materials added, including but not limited to 1, 2, 3, 4 or 5, etc., which can be selected by those skilled in the art as needed.

[0035] As a preferred technical solution of this utility model, the first discharge port in the primary reactor and the second inlet in the intermediate control vessel are connected through a first pipeline.

[0036] Preferably, a first material conveying pump is installed on the first pipeline.

[0037] Preferably, the first material conveying pump is a metering pump.

[0038] As a preferred embodiment of this invention, the second discharge port in the intermediate control vessel is connected to the third inlet port in the secondary reaction vessel via a second pipeline.

[0039] Preferably, a second material conveying pump is provided on the second pipeline.

[0040] Preferably, the second material conveying pump is a metering pump.

[0041] In this invention, the material conveying pump can be a metering pump, used to regulate the flow rate of the conveyed material.

[0042] The multi-chamber continuous reaction apparatus provided by this invention can be used for the preparation of LiFeMnPO4 precursor materials, wherein the precursor material has the chemical formula NH4Fe. x Mn yPO4·H2O, 0 < x < 0.5, 0.5 < y < 1, x + y = 1, the specific process includes the following steps:

[0043] (1) Prepare a ferrous manganese mixed salt solution with a concentration of 2-3 mol / L, a phosphoric acid solution with a concentration of 2-3 mol / L, and an ammonia solution with a concentration of 2-3 mol / L according to the formula.

[0044] (2) The ferrous manganese mixed salt solution, phosphoric acid solution and ammonia solution are added in parallel through the first feed port into the first body of the primary reactor containing the bottom liquid for reaction. At the same time, the first stirring unit is turned on for stirring. The flow rates of the ferrous manganese mixed salt solution, phosphoric acid solution and ammonia solution are independently selected from 80-120 mL / min. When the liquid level rises to more than 3 / 4 of the primary reactor, the first discharge port is opened, and the slurry obtained in the primary reactor is transported through the first material conveying pump on the first pipeline to the second feed port of the intermediate control vessel and into the second body of the vessel.

[0045] (3) After the delivery is completed, close the second feed port of the intermediate control vessel and ensure that the intermediate control vessel is sealed. Open the second stirring unit and then perform pressure reduction treatment on the intermediate control vessel: reduce the pressure at a rate of 0.005-0.02 MPa / min, that is, adjust the three-way valve to draw gas through the pressure regulating pipeline to the gas inlet and outlet of the intermediate control vessel with the gas buffer at the lower end until the pressure inside the second vessel is below -0.3 MPa. After the pressure is maintained for 5-20 minutes, the pressure inside the second vessel in the intermediate control vessel is restored to atmospheric pressure. That is, adjust the three-way valve to charge the gas inlet and outlet of the gas buffer at the lower end through the pressure regulating pipeline. The gas used for charging includes nitrogen or inert gas.

[0046] (4) The concentration of ammonia in the solution is tested using a concentration detector. Ammonia solution is then added to the intermediate control vessel through the fourth inlet at the top of the second vessel. Next, a pressurization process is performed: the three-way valve is adjusted to pressurize the intermediate control vessel through the pressure regulating pipeline to the inlet / outlet of the gas buffer located at the lower end. The pressurized gas includes nitrogen or an inert gas. The pressure is increased to 0.1-0.5 MPa at a rate of 0.01-0.05 MPa / min. After a pressure-holding reaction for 20-30 minutes, the pressure inside the intermediate control vessel is restored to atmospheric pressure. Specifically, the three-way valve is adjusted to expel the gas from the intermediate control vessel through the pressure regulating pipeline and the inlet / outlet. During the depressurization and pressurization process of the intermediate control vessel, the gas extracted through the pressure regulating pipeline is recovered into the ammonia stripping equipment for ammonia recovery.

[0047] (5) Open the second outlet at the bottom of the intermediate control vessel and transport the slurry obtained in step (4) through the second material conveying pump and the second pipeline to the third inlet of the secondary reactor, reaching the interior of the third reactor body. In the secondary reactor, add the ferrous manganese mixed salt solution, phosphoric acid solution and ammonia solution prepared in step (1) in parallel through the fifth inlet to the interior of the third reactor body for reaction. At the same time, open the third stirring unit to stir the slurry inside the reactor body. The flow rates of the ferrous manganese mixed solution, phosphoric acid solution and ammonia solution are independently selected from 80-120 mL / min until the particle size D50 of the target product reaches 45-55 μm, and then stop the reaction.

[0048] (6) The product obtained from the third vessel body is taken out from the third discharge port, and after separation, washing and drying, the precursor material is obtained.

[0049] In this invention, a specific multi-chamber continuous reaction device is used to prepare the precursor material of LiFeMnPO4. The specific reaction principle is as follows:

[0050] During the decompression stage, according to Henry's Law, as the gas pressure inside the reactor decreases, trace amounts of dissolved gas escape from the solution. The pores between the generated particles are more easily wetted by the solution, reducing the porosity and specific surface area of ​​the finished particles. In the intermediate control vessel of the multi-chamber continuous reaction device provided by this invention, during the decompression stage, as the gas pressure inside the reaction chamber decreases, the partial pressure of ammonia decreases, causing the NH3·H2O in the slurry to decompose, ammonia to escape, and the NH4 in the slurry to... + As the concentration decreases, the pH of the slurry decreases, and the decrease in pH promotes the growth of H2PO4 in the slurry. - The secondary ionization proceeds in reverse, leading to a decrease in PO43- concentration (physical level). According to the solubility product principle, supersaturation is a crucial driving force for crystal growth. The decrease in PO43- concentration reduces the supersaturation of ammonium iron manganese phosphate in the solution, thus favoring crystal growth. This makes it easier for the crystal to grow on the microporous structure wetted by gas overflow, further reducing the internal porosity of the finished particles and resulting in denser, higher-strength ammonium iron manganese phosphate particles (the wetted channels facilitate solute entry, physics-reaction kinetics). Furthermore, under negative pressure, the migration energy of vacancies within the crystal decreases, and the system tends to minimize energy. In ordered arrangement, the interaction energy between Mn / Fe atoms is lower and more stable. The slower growth rate provides sufficient time and space for the atoms to migrate to more suitable lattice positions, forming an ordered arrangement (reaction kinetics).

[0051] During the pressurization stage, nitrogen / inert gas is used for pressurization, while a small amount of ammonia is added to replenish the ammonia removed during the depressurization stage. Pressurization increases the supersaturation (ΔC) of the slurry, accelerates the solute mass transfer rate, and reduces intergranular pores caused by Ostwald ripening (Ostwald ripening refers to the process in which large grains grow at the expense of small grains in a polycrystalline system of solid matter; reducing intergranular pores is beneficial to improving the performance of the material). Subsequently, under high pressure, the interaction forces between precursor particles are enhanced, promoting close packing of particles, which is also beneficial to obtaining high-density ammonium iron manganese phosphate particles, further improving the quality of the product.

[0052] Compared with the prior art, the present invention has at least the following beneficial effects:

[0053] In the multi-chamber continuous reaction device provided by this utility model, the raw materials can undergo preliminary reaction in the primary reactor to generate crystal nuclei and perform preliminary growth. The intermediate control reactor is used to modify the microstructure of the material. Through the gas inlet and outlet set at the top of the reactor body and the pressure regulating pipeline set outside the reactor body and connected to the gas inlet and outlet, gas can be charged and evacuated into the intermediate control reactor to treat the material inside the reactor body with positive and negative pressure. This achieves pressure-based control of nucleation rate and particle structure, promotes the stacking of plate-like morphology, reduces the voids inside the particles to form a denser morphology, and can improve the loose packing density and tap density of the prepared precursor material, thereby improving the compaction density of the subsequently prepared cathode material. The secondary reactor performs a secondary feeding reaction to achieve the goal of continuously preparing precursor materials with excellent consistency in various physicochemical properties, morphology, structure and size, and to ensure that the obtained precursor material has a high particle density, so as to improve production capacity and reduce costs. Attached Figure Description

[0054] Figure 1 This is the multi-chamber continuous reaction device provided in Embodiment 1 of this utility model.

[0055] In the diagram, 1 is the primary reactor; 101 is the first reactor body; 102 is the first feed inlet; 103 is the first discharge outlet; 104 is the first stirring unit; 2 is the intermediate control reactor; 201 is the second reactor body; 202 is the second feed inlet; 203 is the second discharge outlet; 204 is the second stirring unit; 205 is the concentration detector; 206 is the gas inlet / outlet; A is the lower end of the gas inlet / outlet; 207 is the fourth feed inlet; 208 is the gas buffer; 3 is the secondary reactor; 301 is the third reactor body; 302 is the third feed inlet; 303 is the third discharge outlet; 304 is the third stirring unit; 305 is the fifth feed inlet; 4 is the pressure regulating pipeline; B is the upper end of the pressure regulating pipeline; 5 is the three-way valve; 6 is the ammonia stripping equipment; 7 is the first pipeline; 8 is the first material conveying pump; 9 is the second pipeline; 10 is the second material conveying pump. Detailed Implementation

[0056] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of this utility model and do not represent or limit the scope of protection of this utility model. The scope of protection of this utility model is determined by the claims.

[0057] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0058] Example 1

[0059] This embodiment provides a multi-chamber continuous reaction device, the structural schematic diagram of which is shown below. Figure 1 As shown, it includes a primary reaction vessel 1, an intermediate control vessel 2, a secondary reaction vessel 3, a pressure regulating pipeline 4, a three-way valve 5, and an ammonia stripping device 6 connected in sequence.

[0060] The primary reactor 1 includes a first reactor body 101, three first feed inlets 102 and first discharge outlets 103 respectively disposed at the top and bottom of the first reactor body 101, and a first stirring unit 104 disposed inside the first reactor body 101.

[0061] The intermediate control vessel 2 includes a second vessel body 201, a second inlet 202, a second outlet 203, a second stirring unit 204, a concentration detector 205, an inlet / outlet 206, and a fourth inlet 207. The second inlet 202 and the second outlet 203 are respectively located at the top and bottom of the second vessel body 201. The second stirring unit 204 is located inside the second vessel body 201. The concentration detector 205 is located inside the second vessel body 201 and is spaced apart from the second stirring unit 204. The inlet / outlet 206 and the fourth inlet 207 are also located at the top of the second vessel body 201. A gas buffer 208 is provided at the lower end A of the inlet / outlet 206, located inside the second vessel body 201. The gas buffer 208 is a porous rod-shaped structure made of polyethylene.

[0062] The pressure regulating pipeline 4 is located above the second vessel body 201. The upper end of the inlet / outlet 206 is connected to the pressure regulating pipeline 4 located outside the second vessel body 201. The three-way valve 5 is located on the pressure regulating pipeline 4. The upper end B of the pressure regulating pipeline 4 is connected to the ammonia stripping equipment 6.

[0063] The secondary reactor 3 includes a third reactor body 301, a third feed inlet 302 and a third discharge outlet 303 respectively disposed at the top and bottom of the third reactor body 301, and a third stirring unit 304 disposed in the middle region inside the third reactor body 301. The top of the third reactor body 301 is also provided with three fifth feed inlets 305.

[0064] The first discharge port 103 in the primary reactor 1 is connected to the second inlet 202 in the intermediate control vessel 2 through a first pipe 7. A first material conveying pump 8 is installed on the first pipe 7, and the first material conveying pump 8 is a metering pump. The second discharge port 203 in the intermediate control vessel 2 is connected to the third inlet 302 in the secondary reactor 3 through a second pipe 9. A second material conveying pump 10 is installed on the second pipe 9, and the second material conveying pump 10 is a metering pump.

[0065] This embodiment also provides a method for preparing LiFeMnPO4 precursor materials based on the above-mentioned multi-chamber continuous reaction device, wherein the precursor material has the chemical formula NH4Fe. 0.4 Mn 0.6 The specific process for PO4·H2O includes the following steps:

[0066] (1) Prepare a 2.1 mol / L ferrous manganese mixed salt solution, a 2.1 mol / L phosphoric acid solution and a 2.1 mol / L ammonia solution according to the formula. The mixed salt in the ferrous manganese mixed salt solution includes ferrous sulfate and manganese sulfate in a molar ratio of 0.4:0.6.

[0067] (2) The ferrous manganese mixed salt solution, phosphoric acid solution and ammonia solution from step (1) are fed into the first vessel body 101 of the primary reactor 1 containing deionized water solution through three first feed ports 102. The height of the deionized water in the primary reactor 1 reaches 1 / 2 (10L) of the height of the first vessel body 101 for reaction. At the same time, the first stirring unit 104 is turned on for stirring at a stirring rate of 550rpm. The flow rates of the ferrous manganese mixed salt solution, phosphoric acid solution and ammonia solution are all 100mL / min. When the liquid level rises to 3 / 4 (15L) of the first vessel body 101, the first discharge port 103 of the primary reactor 1 is opened, and the slurry obtained in the primary reactor 1 is transported to the second feed port 202 of the intermediate control vessel 2 through the first material conveying pump 8 on the first pipeline 7 to reach the interior of the second vessel body 201.

[0068] (3) After the delivery is completed, close the second feed port 202 of the intermediate control vessel 2 and ensure that the intermediate control vessel 2 is sealed. Open the second stirring unit 204 and the stirring speed is 350 rpm. Then, perform pressure reduction treatment on the intermediate control vessel 2: reduce the pressure at a rate of 0.01 MPa / min, that is, adjust the three-way valve 5 to pump gas into the gas inlet and outlet port 206 of the gas buffer 208 at the lower end of the intermediate control vessel 2 through the pressure regulating pipeline 4 until the pressure inside the second vessel body 201 is -0.3 MPa. After the pressure is maintained for 10 minutes, restore the pressure inside the second vessel body 201 in the intermediate control vessel 2 to atmospheric pressure, that is, adjust the three-way valve 5 to charge nitrogen into the gas inlet and outlet port 206 of the gas buffer 208 at the lower end through the pressure regulating pipeline 4.

[0069] (4) The concentration of ammonia in the solution is tested using a concentration detector 205. 250 mL of a 2.1 mol / L ammonia solution is injected into the intermediate control vessel 2 through the fourth inlet 207 at the top of the second vessel 201. Then, a pressurization process is performed: the three-way valve 5 is adjusted to purge nitrogen gas through the pressure regulating pipe 4 to the inlet / outlet 206, where a gas buffer 208 is located at the lower end. The pressure is increased to 0.3 MPa at a rate of 0.03 MPa / min. After a pressure-holding reaction for 25 minutes, the pressure inside the second vessel 201 in the intermediate control vessel 2 is restored to atmospheric pressure. That is, the three-way valve 5 is adjusted to purge the gas from the intermediate control vessel 2 through the pressure regulating pipe 4 and the inlet / outlet 206 until the pressure in the second vessel 201 is atmospheric pressure. During the depressurization and pressurization processes in the intermediate control vessel 2, the gas extracted through the pressure regulating pipe 4 is recovered into the ammonia stripping equipment 6 for ammonia recovery.

[0070] (5) Open the second discharge port 203 at the bottom of the intermediate control vessel 2 and transport the slurry obtained in step (4) through the second material conveying pump 10 and the second pipeline 9 to the third feed port 302 of the secondary reactor 3 to the interior of the third vessel body 301. In the secondary reactor 3, the ferrous manganese mixed salt solution, phosphoric acid solution and ammonia solution from step (1) are added to the interior of the third vessel body 301 in parallel through the three fifth feed ports 305 to carry out the reaction. The flow rates of the ferrous manganese mixed salt solution, phosphoric acid solution and ammonia solution are all 100 mL / min. At the same time, the third stirring unit 304 is turned on to stir the slurry inside the vessel body at a stirring rate of 550 rpm until the particle size D50 of the target product reaches 50 μm, and then the reaction is stopped.

[0071] (6) Take out the product obtained from the reaction in the third vessel 301 in step (3) from the third discharge port 303, and after separation, washing and drying, obtain the precursor material.

[0072] Example 2

[0073] The only difference between this embodiment and Embodiment 1 is that the gas buffer in the intermediate control vessel is omitted. All other aspects are the same as in Embodiment 1.

[0074] Example 3

[0075] The only difference between this embodiment and Embodiment 1 is that the concentration tester and the fourth feed port in the intermediate control vessel are omitted; correspondingly, the process of injecting ammonia solution into the intermediate control vessel from the fourth feed port set at the top of the second vessel and the process of testing the ammonia concentration in the solution using a concentration tester are omitted in the precursor material preparation process. All other contents are the same as in Embodiment 1.

[0076] Comparative Example 1

[0077] The only difference between this comparative example and Example 1 is that the intermediate control vessel is omitted. Accordingly, the preparation process of the precursor material provided in this comparative example omits the negative and positive pressure treatment of the product obtained from the primary reactor using the intermediate control vessel in steps (3) and (4). Instead, the product obtained from the primary reactor in step (2) is directly transported to the secondary reactor via a material transfer pump and pipeline for the feeding reaction in step (5) and the process operation in step (6). All other contents are the same as in Example 1.

[0078] Comparative Example 2

[0079] The only difference between this comparative example and Example 1 is that the intermediate control vessel and the secondary reactor are omitted, and only the primary reactor is used for synthesis. Accordingly, the preparation process of the precursor material provided in this comparative example is the same as that in Example 1, only steps (1) and (2) are performed.

[0080] The precursor materials obtained in the above embodiments and comparative examples were tested for their physicochemical properties, namely, the particle size D50, loose packing density (AD), tap density (TD), specific surface area (BET), and average layer thickness ratio (APMT, the average value of the ratio of total packing thickness to the number of single-particle packing layers). The test results are shown in Table 1.

[0081] Table 1

[0082] D50(μm) <![CDATA[AD(g / cm 3 )]]> <![CDATA[TD(g / cm 3 )]]> <![CDATA[BET(m 2 / g)]]> APMT(μm) Example 1 50.37 0.81 1.36 1.24 6.2 Example 2 46.21 0.74 1.27 1.33 3.8 Example 3 45.23 0.76 1.21 1.50 2.5 Comparative Example 1 46.27 0.55 1.14 1.73 1.3 Comparative Example 2 36.89 0.43 0.9 1.99 0.8

[0083] Application Example 1

[0084] The precursor material obtained in Example 1 was heated to 350°C at a rate of 1°C / min and held for 2 hours, then heated to 700°C and held for 10 hours to obtain a deaminated precursor material. The deaminated precursor material, lithium hydroxide, and glucose were wet ball-milled. The molar ratio of lithium hydroxide to the deaminated precursor material was Li:P = 1.05:1, and the mass of glucose accounted for 8 wt% of the total mass of lithium hydroxide and the deaminated precursor material. Then, the mixed product was spray-dried and calcined at 500°C for 10 hours under an argon atmosphere to obtain carbon-coated lithium manganese iron phosphate cathode material.

[0085] Application Example 2-3 and Comparison with Application Example 1-2

[0086] The only difference from Example 1 is that Application Examples 2-3 and Comparative Application Examples 1-2 use the precursor materials prepared in Examples 2-3 and Comparative Examples 1-2, respectively. All other aspects are the same as in Application Example 1.

[0087] The density (PD) of the cathode materials obtained in the above application examples and comparative application examples was tested, and the lithium-ion batteries were assembled for electrochemical testing. The assembly process of the lithium-ion batteries was as follows: the lithium manganese iron phosphate cathode materials provided in application examples 1-3 and comparative application examples 1-2 were mixed with conductive carbon and PVDF in a ratio of 8:1:1. The mixture was then dispersed in methylpyrrolidone (NMP) as a solvent to obtain a cathode slurry, which was uniformly coated on aluminum foil. After coating, the current collector was perforated to obtain a coin-shaped electrode. After vacuum drying at 120°C for 12 hours, a cathode electrode sheet was obtained. The anode was made of lithium metal. 1 mol / L LiPF6 was dissolved in EC and DMC solvents (volume ratio 3:7) as the electrolyte. The cathode, anode, and separator were wound to prepare the battery cell, and then assembled into a lithium-ion battery through encapsulation, electrolyte injection, formation, and capacity testing.

[0088] The electrochemical performance testing conditions for the lithium-ion battery were as follows: at 25℃ and a voltage range of 2.8V-4.25V, the specific capacity and initial coulombic efficiency of the prepared lithium-ion battery at 0.1C were tested, as well as the cycle capacity retention rate after 100 cycles under a 1C charge / 1C discharge regime. The test results are shown in Table 2.

[0089] Table 2

[0090]

[0091] The test results show that:

[0092] (1) By comparing Example 1 and Example 2, and Application Example 1 and Application Example 2, it can be seen that if the multi-chamber continuous reaction device provided by this utility model lacks a gas buffer in the intermediate control vessel, it will lead to material loss and slurry splashing during the depressurization and pressurization process of the slurry in the intermediate control vessel, affecting the performance of the obtained precursor material, thereby causing the loose packing density of the cathode material prepared from the obtained precursor material to decrease and the electrochemical performance to deteriorate.

[0093] (2) By comparing Example 1 and Example 3, and Application Example 1 and Application Example 3, it can be seen that if the concentration detector and the fourth feed port in the intermediate control vessel of the present invention are used to omit the additional addition of ammonia solution and the detection of ammonia in the slurry of the vessel in the reaction process of step (4), the ammonia lost during the gas extraction process will be replenished, resulting in a decrease in the ammonia content in the slurry, which will affect the physicochemical properties of the precursor material, and thus the performance of the cathode material prepared by the subsequent process will decrease.

[0094] (3) It can be seen from the comparison between Example 1 and Comparative Example 1, as well as Application Example 1 and Comparative Application Example 1, that if the multi-chamber continuous reaction device provided by this utility model lacks an intermediate control vessel, the physical and chemical properties of the obtained precursor material will decrease significantly, the particle size, loose packing density, tap density and average layer thickness ratio will decrease significantly, the specific surface area of ​​the material will increase significantly, and thus the electrochemical performance of the cathode material prepared by the precursor material will deteriorate significantly.

[0095] (4) It can be seen from the comparison of Example 1 and Comparative Example 2, as well as Application Example 1 and Comparative Application Example 2, that compared with the reaction in a single reactor, the multi-chamber continuous reaction device provided by this utility model can improve the physicochemical properties of the precursor material and enhance the electrochemical performance of the cathode material prepared from the precursor material.

[0096] In summary, the multi-chamber continuous reaction device provided by this invention allows for the initial reaction of raw materials in the primary reactor, generating crystal nuclei and initiating initial growth. The intermediate control reactor is used to modify the microstructure of the material. Through the gas inlet and outlet ports located at the top of the reactor body, and the pressure regulating pipeline connected to the gas inlet and outlet ports located outside the reactor body, gas can be supplied and evacuated to the intermediate control reactor. This allows for positive and negative pressure treatment of the material inside the reactor body, achieving pressure-based control of the nucleation rate and particle structure, promoting the accumulation of plate-like morphology, reducing internal voids in the particles to form a denser morphology, and improving the loose packing density and tap density of the prepared precursor material, thereby increasing the compaction density of the subsequently prepared cathode material. The secondary reactor performs a secondary feeding reaction, achieving the goal of continuously preparing precursor materials with excellent consistency in various physicochemical properties, morphology, structure, and size, and ensuring that the obtained precursor material has a high particle density, thereby increasing production capacity and reducing costs.

[0097] The applicant declares that the above description is only a specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model fall within the protection and disclosure scope of the present utility model.

Claims

1. A multi-chamber continuous reaction apparatus, characterized by, The multi-chamber continuous reaction device includes a primary reaction vessel, an intermediate control vessel, and a secondary reaction vessel connected in sequence. The primary reactor includes a first reactor body, with a first inlet and a first outlet respectively disposed at the top and bottom of the first reactor body; The intermediate regulating vessel includes a second vessel body, a second inlet and a second outlet respectively provided at the top and bottom of the second vessel body, and an air inlet and outlet provided at the top of the second vessel body. The upper end of the air inlet and outlet is connected to a pressure regulating pipeline provided outside the second vessel body, and the lower end of the air inlet and outlet extends into the interior of the second vessel body. The secondary reactor includes a third vessel body, with a third inlet and a third outlet respectively located at the top and bottom of the third vessel body; The first discharge port of the primary reactor is connected to the second inlet of the intermediate control vessel; the second discharge port of the intermediate control vessel is connected to the third inlet of the secondary reactor.

2. The multi-chamber continuous reaction device according to claim 1, wherein, In the first-stage reaction vessel, a first stirring unit is provided inside the first vessel body.

3. The multi-chamber continuous reaction device of claim 1, wherein, In the intermediate control vessel, a concentration detector is also installed inside the second vessel body.

4. The multi-chamber continuous reaction device of claim 1, wherein, The second vessel body is equipped with a second stirring unit; The second vessel body is also provided with a fourth feed port at the top.

5. The multi-chamber continuous reaction device of claim 4, wherein, In the intermediate control vessel, a gas buffer is provided at the lower end of the inlet and outlet ports; The gas buffer has a porous rod-shaped structure.

6. The multi-chamber continuous reaction device of claim 1, wherein, A three-way valve is installed on the pressure regulating pipeline.

7. The multi-chamber continuous reaction device of claim 1, wherein, The multi-chamber continuous reaction device is also equipped with an ammonia stripping device, which is connected to the upper end of the pressure regulating pipeline.

8. The multi-chamber continuous reaction device of claim 1, wherein, In the secondary reactor, a third stirring unit is provided inside the third reactor body; The top of the secondary reactor is also equipped with a fifth feed inlet.

9. The multi-chamber continuous reaction device of claim 1, wherein, The first discharge port in the primary reactor is connected to the second inlet in the intermediate control vessel via a first pipe. A first material conveying pump is installed on the first pipeline; The first material conveying pump is a metering pump.

10. The multi-chamber continuous reaction device of claim 1, wherein, The second discharge port in the intermediate control vessel is connected to the third inlet port in the secondary reaction vessel via a second pipeline; A second material conveying pump is installed on the second pipeline; The second material conveying pump is a metering pump.

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