Coating device and coating method

Abstract

Provided are a coating device and a coating method with which it is possible to satisfactorily disperse a mixed material onto coated particles to which a coating liquid adheres in the form of a film, and to suppress re-aggregation of the dispersed coated particles. In the dispersion unit (11), a slurry, which is a mixed material of particles to be coated and a coating liquid formed by dissolving the coating material in a solvent, flows into a dispersion passage (21) from a slurry flow path (17), and a dispersion gas heated by a dispersion gas heater (33) flows into the dispersion passage (21) from a dispersion gas flow path (32). In addition, the slurry is dispersed by the flow of the dispersion gas onto the particles to be coated which the surface coating liquid adheres in the form of a film. When the dispersion gas is heated, the dispersion gas having a flow rate such that the ratio of the weight of the dispersion gas to the weight of the particles to be coated is 3: 1 or more flows into the dispersion passage (21), so that the slurry can be satisfactorily dispersed on the particles to be coated to which the surface coating liquid adheres in the form of a film.

Description

Technical Field

[0001] The present invention relates to a coating device and a coating method for coating the surface of a particle to be coated with a coating material. Background Art

[0002] In the surface modification / compounding technology, the coated particles (masterbatch) are combined with a coating material of different particles from the masterbatch, and the surface of the coated particles is coated with the coating material, thereby giving the coated particles various functionalities. This surface modification / compounding technology is widely used in the fields of food, medicine, cosmetics, etc. In addition, it is also used for materials used in electronic components and batteries to improve electrical properties.

[0003] For example, Patent Document 1 discloses a device for manufacturing a composite powder, wherein a coating material is coated on the surface of a coated particle. In the device, the nozzle of the nozzle is configured to face the inside of a dryer. Compressed air is supplied to the nozzle by a compressor, and a mixed material of the coated particle and a coating liquid formed by dissolving the coating material in a solvent is supplied. By supplying compressed air and the mixed material to the nozzle, the dropletized mixed material is sprayed from the nozzle into the dryer. On the other hand, hot air is supplied to the dryer from a hot air inlet provided on the dryer. Thus, the dropletized mixed material is dried to generate a powder in which the surface of the coated particle is coated with a precursor of the coating material. Furthermore, by calcining the precursor of the coating material, a composite powder in which a thin film of the coating material is coated on the surface of the coated particle can be obtained.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2003-93865 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, in the existing device, since the dispersibility of the coated particles in the dryer is low, aggregated particles are easily generated. In addition, sometimes the dispersed coated particles are re-aggregated by liquid cross-linking of the coating liquid attached to the surface, and the aggregated particles are granulated.

[0009] The present invention aims to provide a coating device and a coating method, which can disperse a mixed material well on particles to be coated to which a coating liquid is attached in a film form, and can suppress the reaggregation of the dispersed particles to be coated.

[0010] Means used to solve problems

[0011] In order to achieve the above-mentioned purpose, one aspect of the present invention relates to a coating device including: a mixing material flow path, in which a mixed material formed by mixing coated particles and a coating liquid formed by dissolving the coating material in a solvent flows; a dispersion gas source that outputs a dispersion gas; a dispersion gas flow path, in which the dispersion gas output from the dispersion gas source flows; a dispersion gas heating source that heats the dispersion gas flowing in the dispersion gas flow path; a dispersion section having a dispersion passage connected to the mixing material flow path and the dispersion gas flow path, the mixed material flows from the mixing material flow path into the dispersion passage, the dispersion gas heated by the dispersion gas heating source flows from the dispersion gas flow path into the dispersion passage, and the mixed material is dispersed onto the coated particles to which the coating liquid is attached in the form of a film by the airflow of the dispersion gas; and a control section, wherein the control section controls the dispersion gas source so that the ratio of the weight of the dispersion gas flowing into the dispersion passage to the weight of the coated particles flowing into the dispersion passage is 3:1 or more.

[0012] According to this structure, in the dispersion section, a mixed material of coated particles and a coating liquid formed by dissolving the coating material in a solvent flows from the mixed material flow path into the dispersion path, and the dispersion gas heated by the dispersion gas heating source flows from the dispersion gas flow path into the dispersion path. Furthermore, the mixed material is dispersed on the coated particles by the airflow of the dispersion gas, wherein the coating liquid is attached to the surface of the coated particles in the form of a film. On the basis of the dispersion gas being heated, the dispersion gas flows into the dispersion path at a flow rate of 3:1 or more in which the weight of the dispersion gas is compared with the weight of the coated particles, so that the mixed material can be well dispersed on the coated particles on whose surfaces the coating liquid is attached in the form of a film. In addition, since the dispersion gas is heated, the temperature drop caused by the adiabatic expansion when the dispersion gas flows from the dispersion gas flow path into the dispersion path can be suppressed, and the drying of the coating liquid can be promoted, so that the re-aggregation of the coated particles caused by the liquid cross-linking of the coating liquid can be suppressed.

[0013] Therefore, by drying the coating liquid attached to the surface of the particle to be coated, a powder in which the surface of the particle to be coated is coated with the precursor of the coating material can be generated with good dispersibility.

[0014] In addition, in a coating method corresponding to a coating device according to one aspect of the present invention, a mixed material of coated particles and a coating liquid formed by dissolving a coating material in a solvent is caused to flow from a mixed material flow path into a dispersion path, a dispersion gas is output from a dispersion gas source to a dispersion gas flow path connected to the dispersion path, the dispersion gas flowing in the dispersion gas flow path is heated by a dispersion gas heating source, and the mixed material is dispersed onto the coated particles to which the coating liquid is attached in the form of a film by utilizing the airflow of the dispersion gas flowing from the dispersion gas flow path into the dispersion path, and the ratio of the weight of the dispersion gas flowing into the dispersion path to the weight of the coated particles flowing into the dispersion path is 3:1 or more.

[0015] This method can achieve the same effects as those achieved by the structure of the coating device according to one aspect of the present invention.

[0016] The temperature of the dispersion gas flowing into the dispersion passage is preferably equal to or higher than the boiling point of the solvent.

[0017] This allows the solvent to evaporate from the coating liquid attached to the surface of the coated particles. As a result, the drying of the coating liquid can be further promoted, and the reaggregation of the coated particles caused by liquid crosslinking of the coating liquid can be further suppressed.

[0018] The amount of heat per unit time of the dispersion gas flowing into the dispersion passage is preferably greater than or equal to the amount of heat per unit time required to evaporate the solvent from the mixed material flowing into the dispersion passage.

[0019] Thus, the solvent can also be evaporated from the coating liquid attached to the surface of the coated particles. As a result, the drying of the coating liquid can be further promoted, and the re-aggregation of the coated particles caused by liquid crosslinking of the coating liquid can be further suppressed.

[0020] Another aspect of the present invention relates to a coating device including: a mixing material flow path, in which a mixed material formed by mixing coated particles and a coating liquid formed by dissolving a coating material in a solvent flows; a dispersion gas source that outputs a dispersion gas; a dispersion gas flow path, in which the dispersion gas output from the dispersion gas source flows; a dispersion gas heating source that heats the dispersion gas flowing in the dispersion gas flow path; a dispersion section having a dispersion passage connected to the mixing material flow path and the dispersion gas flow path, the mixed material flows from the mixing material flow path into the dispersion passage, the dispersion gas heated by the dispersion gas heating source flows from the dispersion gas flow path into the dispersion passage, and the mixed material is dispersed onto the coated particles attached in a film form by the coating liquid by the airflow of the dispersion gas; and a control section that controls at least one of the dispersion gas source and the dispersion gas heating source so that the heat of the dispersion gas flowing into the dispersion passage per unit time is greater than or equal to the heat required to evaporate the solvent from the mixed material flowing into the dispersion passage per unit time.

[0021] According to this structure, in the dispersion section, a mixed material of the coated particles and the coating liquid formed by dissolving the coating material in the solvent flows from the mixed material flow path into the dispersion path, and the dispersion gas heated by the dispersion gas heating source flows from the dispersion gas flow path into the dispersion path. And, the mixed material is dispersed on the coated particles whose surfaces are attached to the coating liquid in the form of a film by the airflow of the dispersion gas. On the basis of the dispersion gas being heated, the heat of the dispersion gas flowing into the dispersion path per unit time is greater than or equal to the heat required for evaporating the solvent from the mixed material flowing into the dispersion path per unit time, so that the drying of the coating liquid can be promoted, and thus the re-aggregation of the coated particles caused by the liquid cross-linking of the coating liquid can be suppressed.

[0022] Therefore, by drying the coating liquid attached to the surface of the particles to be coated, a powder having good dispersibility in which the surfaces of the particles to be coated are coated with the precursor of the coating material can be produced.

[0023] In a coating method corresponding to the coating device involved in another aspect of the present invention, a mixed material of coated particles and a coating liquid formed by dissolving a coating material in a solvent is caused to flow from a mixed material flow path into a dispersion path, a dispersion gas is output from a dispersion gas source to a dispersion gas flow path connected to the dispersion path, the dispersion gas flowing in the dispersion gas flow path is heated by a dispersion gas heating source, and the mixed material is dispersed onto the coated particles attached in a film form by the coating liquid using the airflow of the dispersion gas flowing from the dispersion gas flow path to the dispersion path, so that the heat of the dispersion gas flowing into the dispersion path per unit time is greater than or equal to the heat required to evaporate the solvent from the mixed material flowing into the dispersion path per unit time.

[0024] This method can achieve the same effects as those achieved by the configuration of the coating device according to another aspect of the present invention.

[0025] The pressure of the dispersed gas outputted from the dispersed gas source is preferably 0.15 MPa or more. In addition, the pressure here is a gauge pressure, and the atmospheric pressure is 0 Pa.

[0026] This makes it easy to ensure that the ratio of the weight of the dispersed gas to the weight of the particles to be coated is 5:1 or more.

[0027] The mixed material is preferably adjusted to have a solid-liquid ratio (weight of coating material:weight of solvent) of 2:0.5 to 3.

[0028] Thereby, re-aggregation of the coated particles caused by liquid cross-linking of the coating liquid can be further suppressed.

[0029] The particles to be coated may have an average particle diameter within a range of 100 nm to 50 μm.

[0030] The coating device can also be configured to further include: a drying gas flow path in which drying gas flows; and a drying section having a drying passage connected to the drying gas flow path, wherein the coating liquid attached to the coated particles flowing from the dispersion passage into the drying passage is dried by the drying gas flowing from the drying gas flow path into the drying passage.

[0031] This structure allows the coating liquid attached to the surface of the coated particles to be dried, and a powder with good dispersibility can be generated in which the surface of the coated particles is coated with the precursor of the coating material. In addition, since the drying of the coating liquid is promoted in the dispersion section (dispersion passage), the coating liquid can be dried well in the drying passage. As a result, the powder (including the powder of the coated particles) flowing from the dispersion passage into the drying passage is prevented from adhering to the inner surface of the drying passage, and the cleaning frequency in the drying passage can be reduced.

[0032] The coating apparatus may be further configured to include a drying gas heating source for heating the drying gas flowing through the drying gas flow path.

[0033] By heating the drying gas, the coating liquid adhering to the surface of the coated particles can be dried more effectively, thereby further generating a powder with good dispersibility in which the surface of the coated particles is covered with the precursor of the coating material.

[0034] Effects of the Invention

[0035] According to the present invention, the mixed material can be well dispersed on the coated particles to which the coating liquid is attached in a film form, and the reaggregation of the dispersed coated particles can be suppressed. As a result, by drying the coating liquid attached to the coated particles, a powder with good dispersibility can be generated in which the surface of the coated particles is coated with the precursor of the coating material. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The structure of a coating device according to a first embodiment of the present invention is diagrammatically shown.

[0037] Figure 2 The structure of a coating device according to a second embodiment of the present invention is diagrammatically shown.

[0038] Description of Reference Numerals

[0039] 1. 101 coating device

[0040] 11.111 Distributed Department

[0041] 13 Drying Section

[0042] 17 Slurry flow path (mixed material flow path)

[0043] 21, 121 Dispersed Path

[0044] 31 Compressor (dispersed gas source)

[0045] 32 Dispersed gas flow path

[0046] 33 Dispersed gas heater (dispersed gas heating source)

[0047] 41 Drying container (drying passage)

[0048] 45 Drying gas flow path

[0049] 61 Control Department DETAILED DESCRIPTION

[0050] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0051] <First Embodiment>

[0052] Figure 1 The structure of a coating device 1 according to a first embodiment of the present invention is diagrammatically shown.

[0053] The coating device 1 is a device used in a coating process to generate a powder, wherein the surface of a particle to be coated, which is a mother particle, is coated with a precursor of a fine-particle coating material. The coating device 1 includes a dispersion unit 11, a dispersion gas supply unit 12, a drying unit 13, and a collection unit 14.

[0054] The particles to be coated and the coating material are provided to the dispersing section 11 in the form of a slurry (mixed material) obtained by mixing the particles to be coated with a coating liquid formed by dissolving the coating material in a solvent. The dispersing section 11 has a structure of a collision-type high-speed airflow dispersing unit. In the dispersing section 11 having the collision-type high-speed airflow dispersing unit structure, a plurality of high-speed airflows collide at a collision position CP, and at the collision position CP, the slurry is dispersed onto the particles to be coated, the surfaces of which are attached with the coating liquid in a film-like state, by the shear force from the high-speed airflow.

[0055] Specifically, a slurry is prepared in a glove box isolated from the outside air. In the preparation of the slurry, the coated particles and the coating liquid are weighed separately so that the slurry has a predetermined solid-liquid ratio, for example, the solid-liquid ratio is in the range of 2:0.5 to 3. The slurry prepared to a predetermined solid-liquid ratio is stored in a slurry tank 15. In the slurry tank 15, the slurry is stirred by a stirring mechanism 16 such as a magnetic stirrer. One end of the slurry flow path 17 is connected to the slurry tank 15. A slurry pump 18 is installed in the middle of the slurry flow path 17.

[0056] The dispersion section 11 (high-speed airflow dispersion unit) includes a dispersion passage 21. The dispersion passage 21 includes a slurry inflow passage 22 and dispersion gas inflow passages 23, 24. The slurry inflow passage 22 extends linearly in the up-down direction. The dispersion gas inflow passages 23, 24 are arranged to be divided into one side and the other side in a direction orthogonal to the up-down direction relative to the slurry inflow passage 22. The dispersion gas inflow passages 23, 24 are inclined at a predetermined angle (for example, 45°) relative to the up-down direction, so that the closer to the collision position CP set in the slurry inflow passage 22, the lower the position. The dispersion gas inflow passages 23, 24 are connected to the slurry inflow passage 22, and the lower ends of the dispersion gas inflow passages 23, 24 on the collision position CP side are open toward the collision position CP.

[0057] The other end of the slurry flow path 17 is connected to the upper end of the slurry inflow path 22. Under the action of the slurry pump 18, the slurry is sucked out from the slurry tank 15 to the slurry flow path 17, and the slurry flowing through the slurry flow path 17 flows into the slurry inflow path 22. The slurry flowing into the slurry inflow path 22 flows along the slurry inflow path 22 toward the lower end.

[0058] The dispersion gas supply unit 12 includes a compressor 31 , a dispersion gas flow path 32 , and a dispersion gas heater 33 .

[0059] The compressor 31 outputs air as dispersion gas.

[0060] One end of the dispersed gas flow path 32 is connected to the compressor 31. The air output from the compressor 31 flows into the dispersed gas flow path 32. The other end of the dispersed gas flow path 32 is branched into branch paths 34 and 35. The end of the branch path 34 is connected to the upper end of the dispersed gas inflow path 23, and the end of the branch path 35 is connected to the upper end of the dispersed gas inflow path 24.

[0061] The dispersion gas heater 33 is disposed at a position closer to the compressor 31 than the branch point of the branch paths 34 and 35 in the dispersion gas flow path 32 , and heats the air flowing through the dispersion gas flow path 32 .

[0062] In addition, in the middle of the dispersed gas flow path 32, between the compressor 31 and the dispersed gas heater 33, an on-off valve 36 and a mist separator (dryer) 37 are installed in this order from the compressor 31 side. The on-off valve 36 opens and closes the dispersed gas flow path 32 to switch between allowing and preventing the flow of air in the dispersed gas flow path 32. The mist separator 37 removes moisture from the air flowing in the dispersed gas flow path 32.

[0063] When the on-off valve 36 is open, the air output from the compressor 31 flows to the dispersed gas inflow passages 23 and 24 through the dispersed gas flow passage 32. While the air is flowing through the dispersed gas flow passage 32, moisture is removed from the air by the mist separator 37, and the air is heated by the dispersed gas heater 33. As a result, the air flowing through the dispersed gas flow passage 32 becomes dry heated air that is dehumidified and heated, and the dry heated air flows from the dispersed gas flow passage 32 (branch passages 34 and 35) into the dispersed gas inflow passages 23 and 24. While the dry heated air flows through the dispersed gas inflow passages 23 and 24, the flow velocity of the dry heated air increases significantly, for example, the flow velocity of the dry heated air reaches a speed of sound or higher.

[0064] Thus, the high-speed airflow of the dry heated air is ejected from the lower ends of the dispersed gas inflow passages 23 and 24 toward the collision position CP, and these high-speed airflows collide at the collision position CP. The slurry flowing toward the lower end in the slurry inflow passage 22 is subjected to the shear force from the high-speed airflow at the collision position CP and is dispersed onto the coated particles on the surface of which the coating liquid is attached in a film-like manner.

[0065] In addition, various gases such as nitrogen, carbon dioxide, or inert gas can be used as the dispersion gas in addition to air.

[0066] The drying section 13 includes a drying container 41. The drying container 41 integrally includes: a cylindrical portion 42 having a cylindrical peripheral surface; and a conical portion 43 connected to the cylindrical portion 42, and the conical portion 43 is substantially conical in shape and narrows as it moves away from the cylindrical portion 42. The drying container 41 is configured so that the center line of the cylindrical portion 42 extends in the up-down direction directly below the dispersion section 11. A dry gas inlet portion 44 is provided on the peripheral surface of the cylindrical portion 42. One end of a dry gas flow path 45 is connected to the dry gas inlet portion 44. The other end of the dry gas flow path 45 is connected to an air intake filter 46. In addition, a midway portion of the dry gas flow path 45 passes through a dry gas heater 47.

[0067] The collecting section 14 includes a collecting cyclone 51 and a collecting filter 52. One end of an air intake pipe 53 is connected to the collecting cyclone 51. The other end of the air intake pipe 53 is connected to the suction port of a drying blower 54. In addition, a powder introduction section 55 is provided on the collecting cyclone 51. One end of a sanitary pipe 56 is connected to the powder introduction section 55. The other end of the sanitary pipe 56 is connected to the lower end of the drying container 41. The collecting filter 52 is installed in the middle of the air intake pipe 53.

[0068] When the drying blower 54 is operated, the air in the collection cyclone 51 is sucked out by the air inlet pipe 53, and the inside of the collection cyclone 51 becomes negative pressure. When the inside of the collection cyclone 51 becomes negative pressure, the inside of the drying container 41 becomes negative pressure through the sanitary pipe 56. Due to the negative pressure in the drying container 41, air (atmosphere) is sucked into the drying gas flow path 45 through the air inlet filter 46, and the air flows into the drying container 41 in the drying gas flow path 45 as dry gas. While the air flows in the dry gas flow path 45, the air is heated by the dry gas heater 47. As a result, the air flowing in the dry gas flow path 45 becomes heated air, and the heated air flows from the dry gas flow path 45 into the drying container 41 through the dry gas inlet portion 44.

[0069] The dry gas inlet 44 and the dry gas flow path 45 are formed so that the heated air is blown out from the dry gas inlet 44 in a tangential direction of the inner peripheral surface of the cylindrical portion 42 of the dry container 41. Therefore, the heated air introduced into the dry container 41 from the dry gas inlet 44 becomes a vortex-shaped airflow flowing along the inner peripheral surface of the cylindrical portion 42.

[0070] On the other hand, the drying container 41 is connected to the slurry inflow passage 22 of the dispersion section 11 as a drying passage. As a result, the coated particles with the coating liquid attached to the surface in the form of a film flow from the slurry inflow passage 22 into the drying container 41. The powder containing the coated particles is transported from the cylindrical portion 42 to the conical portion 43 in the drying container 41 along with the vortex-like airflow of the heated air generated in the drying container 41. During the transportation process, the coating liquid attached to the surface of each coated particle is dried, thereby generating a powder (hereinafter referred to as "xerogel powder"), wherein the surface of each coated particle is coated with a precursor of the coating material. In addition, the droplets of the coating liquid that are not attached to the surface of the coated particles are dried to generate a coating liquid dry sheet.

[0071] The dry gel powder and the coating liquid dried flakes that have reached the lower end of the drying container 41 flow through the sanitary pipe 56 under the negative pressure in the collecting cyclone 51 and are sucked into the collecting cyclone 51. In the collecting cyclone 51, the airflow containing the dry gel powder and the coating liquid dried flakes rotates, and the dry gel powder with a relatively large particle size and mass and the coating liquid dried flakes with a relatively small particle size and mass are separated by the centrifugal force and gravity. The dry gel powder is stored in a collecting box 57 connected to the lower end of the collecting cyclone 51.

[0072] The dried pieces of the coating liquid separated by the collecting cyclone 51 are sucked out by the air intake pipe 53 along with the air, and are collected by the collecting filter 52. Therefore, the collecting filter 52 allows only the air to pass therethrough.

[0073] In addition, various gases such as nitrogen, carbon dioxide, or inert gas can be used as the dry gas in addition to air.

[0074] In addition, the coating device 1 also includes a control unit 61. The control unit 61 is configured to include a microcomputer (microcontroller). The microcomputer has a built-in CPU and memory. The memory includes, for example, a non-volatile memory such as a flash memory or E2PROM that can rewrite data and a volatile memory such as a DRAM (Dynamic Random Access Memory). Programs for controlling the various parts of the coating device 1 are stored in the non-volatile memory. The CPU executes the program stored in the non-volatile memory, and the volatile memory is used as a working area when executing the program. In addition, the memory stores various data required for controlling each part.

[0075] The control of each unit by the control unit 61 will be described later.

[0076] In addition, when the coating device 1 is used to generate a positive electrode active material powder for an all-solid-state battery, the coated particles are, for example, lithium metal composite oxides, which are particles with an average particle size of about 2 to 30 μm. The metal elements constituting the powder include Co, Ni, Mn, Ti, Fe, Al, etc., but other elements are sometimes included to improve the electrochemical properties. Specifically, the particles constituting the powder include LiCoO2, LiNiO2, LiMn2O4, LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O2、Li4Ti5O 12 、LiFePO4、LiNi 0.8 Co 0.15 Al 0.05 O2 and other particles.

[0077] For example, when the coating material combined with the coated particles is lithium niobate (LiNbO3), the coating liquid is an alkoxide solution of lithium and niobium, ethoxy lithium (LiOC2H5) can be used as a lithium source, pentaethoxy niobium (Nb(OC2H5)5) can be used as a niobium source, and ethanol can be used as a solvent. When the coating liquid is an alkoxide solution of lithium and niobium, by calcining the dry gel powder collected by the collecting part 14 of the coating device 1 at a temperature of more than 250°C and less than 500°C, a positive electrode active material powder in which the coated particles are coated with a lithium niobate film can be obtained.

[0078] <Second Embodiment>

[0079] Figure 2 The structure of a coating device 101 according to a second embodiment of the present invention is shown in a diagrammatic manner. Figure 2 In, with Figure 1The parts corresponding to the parts shown are marked with the same reference numerals. In addition, the description of the parts marked with the same reference numerals will be omitted below.

[0080] The coating device 101 includes a dispersing unit 111. Figure 1 In the coating device 1 shown, the dispersion section 11 has a structure of a collision-type high-speed airflow dispersion unit, whereas the dispersion section 111 has a structure of a Laval-type high-speed airflow dispersion unit. In the dispersion section 111 having the Laval-type high-speed airflow dispersion unit structure, a high-speed airflow having a flow velocity exceeding the speed of sound flows through the slurry, causing the slurry to be subjected to a shear force from the high-speed airflow and thus dispersed onto the coated particles on the surface of which the coating liquid is attached in a film-like manner.

[0081] Specifically, the drying container 41 is arranged in the coating device 101 so that the center line of the drying container 41 of the drying section 13 extends in a direction perpendicular to the vertical direction. In addition, the other end of the dispersion gas flow path 32, that is, the end on the opposite side of the end connected to the compressor 31 of the dispersion gas flow path 32 is not branched.

[0082] The dispersion section 111 includes a dispersion passage 121. The dispersion passage 121 extends in the same direction as the center line of the drying container 41. One end of the dispersion passage 121 is connected to the end surface of the drying container 41 on the opposite side to the conical portion 43, and the dispersion passage 121 is connected to the inside of the drying container 41 as a drying passage. The other end of the dispersion passage 121 is connected to the other end of the dispersion gas flow path 32. In addition, on the dispersion passage 121, the other end of the slurry flow path 17 is connected at a position closer to the drying container 41 side than the connection position of the dispersion gas flow path 32, that is, connected to the end of the slurry flow path 17 on the opposite side of the end connected to the slurry tank 15. And, in the dispersion passage 121, the flow path cross section is contracted-expanded in the middle part between the connection position of the dispersion gas flow path 32 and the connection position of the slurry flow path 17, thereby forming a Laval nozzle.

[0083] The slurry flowing from the slurry flow path 17 into the dispersion path 121 flows toward the drying container 41 in the dispersion path 121. On the other hand, the high-speed airflow of the dry heated air flowing from the dispersion gas flow path 32 into the dispersion path 121 passes through the Laval nozzle, so that its flow velocity is greatly increased, for example, the flow velocity reaches 3 times the speed of sound. The airflow with a flow velocity exceeding the speed of sound flows through the slurry flowing in the dispersion path 121, whereby the slurry is subjected to the shear force from the high-speed airflow, and is dispersed onto the coated particles whose surfaces are attached to the coating liquid in the form of a film.

[0084] <Control content>

[0085] The control unit 61 controls the operation of the compressor 31 so that the ratio of the weight of the dry heated air as the dispersion gas flowing into the dispersion passages 21, 121 to the weight of the coated particles flowing into the dispersion passages 21, 121 is greater than 3:1, preferably within the range of greater than 8:1 and less than 100:1.

[0086] Furthermore, the control unit 61 controls the operation of at least one of the compressor 31 and the dispersion gas heater 33 so that the temperature of the dry heated air flowing into the dispersion passage 21 , 121 reaches or exceeds the boiling point of the solvent contained in the coating liquid.

[0087] Assume that when the pressure of the air output from the compressor 31 is a predetermined value A and the output of the dispersion gas heater 33 is a predetermined value B, the temperature of the dry heated air flowing into the dispersion passages 21 and 121 reaches a predetermined temperature that is higher than the boiling point of the solvent. In this case, if the pressure of the air output from the compressor 31 is reduced from the predetermined value A, the flow rate of the air flowing in the dispersion gas flow passage 32 is reduced, and thus the amount of heat supplied from the dispersion gas heater 33 to the air flowing in the dispersion gas flow passage 32 per unit time increases. Therefore, the temperature of the dry heated air flowing into the dispersion passages 21 and 121 is maintained at or higher than the boiling point of the solvent, and the control unit 61 can reduce the output of the dispersion gas heater 33 from the predetermined value B. On the other hand, if the pressure of the air output from the compressor 31 is increased from the predetermined value A, the flow rate of the air flowing in the dispersion gas flow passage 32 is increased, and thus the amount of heat supplied from the dispersion gas heater 33 to the air flowing in the dispersion gas flow passage 32 per unit time decreases. Therefore, the control unit 61 may increase the output of the dispersion gas heater 33 from the predetermined value B so as to keep the temperature of the dry heated air flowing into the dispersion passage 21 , 121 at or above the boiling point of the solvent.

[0088] However, the ratio of the weight of the dry heated air flowing into the dispersion passages 21, 121 to the weight of the coated particles flowing into the dispersion passages 21, 121 must be maintained at 5:1 or more. That is, the control unit 61 can control the operation of the compressor 31 and the dispersion gas heater 33 while maintaining the ratio of the weight of the dry heated air flowing into the dispersion passages 21, 121 as the dispersion gas to the weight of the coated particles flowing into the dispersion passages 21, 121 at 5:1 or more and maintaining the temperature of the dry heated air flowing into the dispersion passages 21, 121 at a temperature above the boiling point of the solvent, thereby increasing or decreasing the pressure of the air output from the compressor 31 and increasing or decreasing the output of the dispersion gas heater 33.

[0089] In addition, the control unit 61 controls the operation of at least one of the compressor 31 and the dispersed gas heater 33 so that the heat of the dry heated air flowing into the dispersed passages 21, 121 as a dispersed gas per unit time is greater than the heat required to evaporate the solvent from the coating liquid flowing into the dispersed passages 21, 121 per unit time. Preferably, the heat of the dry heated air flowing into the dispersed passages 21, 121 as a dispersed gas per unit time is in the range of 1.1 to 3 times the heat required to evaporate the solvent from the coating liquid flowing into the dispersed passages 21, 121 per unit time.

[0090] In order to ensure that the ratio of the weight of the dry heated air flowing into the dispersion passages 21, 121 to the weight of the coated particles flowing into the dispersion passages 21, 121 is greater than 5:1, the control unit 61 controls the operation of the compressor 31 so that the pressure of the air output by the compressor 31 is greater than 0.15 MPa, preferably 0.2-0.7 MPa.

[0091] In the above embodiment, the compressor 31 is cited as a dispersed gas source for outputting dispersed gas. However, the dispersed gas source is not limited to the compressor 31 as long as it can output dispersed gas with a pressure of 0.15 MPa or more to the dispersed gas flow path 32.

[0092] <Effects>

[0093] As described above, in the dispersion section 11, 111, a slurry of a mixed material formed by mixing the coated particles and the coating liquid formed by dissolving the coating material in the solvent flows from the slurry flow path 17 into the dispersion passages 21, 121, and the dispersion gas heated by the dispersion gas heater 33 flows from the dispersion gas flow path 32 into the dispersion passages 21, 121. And, by the airflow of the dispersion gas, the slurry is dispersed on the coated particles whose surfaces are attached to the coating liquid in a film-like manner. On the basis of the dispersion gas being heated, the dispersion gas flows into the dispersion passages 21, 121 at a flow rate of 3:1 or more in which the weight of the dispersion gas is to the weight of the coated particles, so that the slurry can be well dispersed on the coated particles whose surfaces are attached to the coating liquid in a film-like manner. In addition, since the dispersion gas is heated, the temperature drop caused by the adiabatic expansion when the dispersion gas flows from the dispersion gas flow path 32 into the dispersion passages 21, 121 can be suppressed, and the drying of the coating liquid can be promoted, so that the re-aggregation of the coated particles caused by the liquid cross-linking of the coating liquid can be suppressed.

[0094] Therefore, by drying the coating liquid attached to the particles to be coated, a powder with good dispersibility in which the surfaces of the particles to be coated are coated with the precursor of the coating material can be produced.

[0095] The temperature of the dispersion gas flowing into the dispersion passages 21, 121 is preferably above the boiling point of the solvent. Thus, the solvent can be evaporated from the coating liquid attached to the surface of the coated particles. As a result, the drying of the coating liquid can be further promoted, and thus the re-aggregation of the coated particles caused by the liquid cross-linking of the coating liquid can be further suppressed.

[0096] It is preferred that the heat of the dispersion gas flowing into the dispersion passages 21, 121 per unit time is greater than or equal to the heat required per unit time to evaporate the solvent from the slurry flowing into the dispersion passages 21, 121. Thus, the solvent can also be evaporated from the coating liquid attached to the surface of the coated particles. As a result, the drying of the coating liquid can be further promoted, so that the re-aggregation of the coated particles caused by the liquid cross-linking of the coating liquid can be further suppressed.

[0097] When the heat of the dispersion gas flowing into the dispersion passages 21, 121 per unit time is greater than or equal to the heat required for evaporating the solvent from the slurry flowing into the dispersion passages 21, 121 per unit time, the ratio of the weight of the dry heated air flowing into the dispersion passages 21, 121 to the weight of the coated particles flowing into the dispersion passages 21, 121 does not necessarily have to be maintained at 3:1 or more, but it is preferably maintained at 3:1 or more. By maintaining the ratio at 3:1 or more, the slurry can be well dispersed on the coated particles whose surfaces are coated with the coating liquid in the form of a film.

[0098] The pressure of the dispersion gas (air) outputted from the compressor 31 is preferably 0.15 MPa or more. This makes it easy to ensure that the ratio of the weight of the dispersion gas to the weight of the particles to be coated is 3:1 or more.

[0099] Preferably, the slurry is adjusted to have a solid-liquid ratio of 2:0.5 to 3. This can further suppress reaggregation of the coated particles due to liquid crosslinking of the coating liquid.

[0100] The coating device 1 includes a drying section 13, heated air is supplied from a drying gas flow path 45 through a drying gas inlet 44 to a drying container 41 of the drying section 13, and powder including particles to be coated with a coating liquid attached to the surface in a film form flows in from a dispersing section 11. The powder is transported along with the airflow of the heated air, and during the transport, the coating liquid attached to the surface of the particles to be coated is dried. Since the drying of the coating liquid is promoted in the dispersing section 11, the coating liquid can be dried well in the drying section 13. As a result, the powder flowing into the drying section 13 from the dispersing section 11 can be prevented from adhering to the inner surface of the drying container 41, and the frequency of cleaning the drying container 41 can be reduced.

[0101] <Modification>

[0102] As mentioned above, although two embodiments of the present invention have been described, the present invention can also be implemented in other forms.

[0103] For example, the present invention is not limited to the application in the generation of positive electrode active material powder for all-solid-state batteries, but can also be applied to the manufacturing process of food, medicine, cosmetics, electronic components, etc. In this case, the coated particles can also be particles with an average particle size of 100 nm or more and 50 μm or less.

[0104] In addition, the above-mentioned structure can be subjected to various design changes within the scope of the features described in the claims.

[0105] [Example]

[0106] A more specific embodiment is described below. The present invention is not limited to this embodiment.

[0107] <Adjustment of coating liquid>

[0108] 142.96 g of ammonia water with a concentration of 28% by mass was mixed with 848.49 g of ion exchange water, and the diluted ammonia water was cooled. On the other hand, 848.72 g of ion exchange water and 17.97 g of lithium hydroxide monohydrate (LiOH·H2O) were added to 1070.62 g of hydrogen peroxide water with a concentration of 30% by mass in a container, and stirred to dissolve the lithium hydroxide monohydrate. Furthermore, 71.24 g of niobic acid (Nb2O5·4.09H2O (Nb2O5 purity 78.3%)) was added to the solution in the container, and the diluted ammonia water was added to the container, and the solution was stirred well while the container was cooled, thereby obtaining a transparent coating liquid. The coating liquid prepared in this way was used in the following Examples 1 to 3 and Comparative Examples.

[0109] <Example 1>

[0110] 50 g of coating liquid was added to a 300 ml container, and while stirring with a magnetic stirrer, 100 g of lithium cobalt oxide (LiCoO2) with an average particle size of 5 μm as coated particles (positive electrode active material) was added, and stirred for several minutes to obtain a slurry.

[0111] use Figure 1 The coating device of the structure shown disperses the slurry onto the coated particles whose surfaces are adhered to by the coating liquid in the form of a film, and dries the coating liquid adhered to the surface of each coated particle, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material.

[0112] Specifically, the pressure of the air (compressed air) output from the compressor 31 is set to 0.5 MPa, and the air flowing through the dispersion gas flow path 32 at a flow rate of 320 L / min is heated to 200°C by the dispersion gas heater 33, and the air is supplied from the dispersion gas flow path 32 to the dispersion section 11 (collision-type high-speed airflow dispersion unit). On the other hand, the slurry is introduced into the dispersion section 11 from the slurry flow path 17 at a rate of 8 g / min, and the slurry is dispersed on the coated particles whose surfaces are attached with the coating liquid in the form of a film. In addition, the coated particles whose surfaces are attached with the coating liquid in the form of a film are flowed into the drying container 41 of the drying section 13, and the coating liquid attached to the surface of each coated particle is dried in the drying container 41, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material.

[0113] Then, the dry gel powder is collected by the collecting part 14 and calcined at a predetermined temperature to obtain a positive electrode active material powder in which lithium cobalt oxide as coated particles is coated with a lithium niobate thin film.

[0114] In Example 1, the ratio of the weight of the air flowing into the dispersing section 11 to the weight of the coated particles flowing into the dispersing section 11 (hereinafter referred to as the "mixing ratio") was 80:1, and the ratio of the heat of the air flowing into the dispersing section 11 per unit time to the heat required to evaporate the solvent from the coating liquid flowing into the dispersing section 11 per unit time (hereinafter referred to as the "heat ratio") was 6:1. The solid-liquid ratio of the slurry was 2:1. In Example 1, the powder did not adhere to the inner surface of the drying container 41, nor did aggregated particles form, and no reaggregation of the temporarily dispersed coated particles was observed.

[0115] <Example 2>

[0116] 50 g of coating liquid was added to a 300 ml container, and while stirring with a magnetic stirrer, 100 g of lithium cobalt oxide (LiCoO2) with an average particle size of 5 μm as coated particles (positive electrode active material) was added, and stirred for several minutes to obtain a slurry.

[0117] use Figure 1 The coating device of the structure shown disperses the slurry onto the coated particles whose surfaces are attached with the coating liquid in the form of a film, and dries the coating liquid attached to the surface of each coated particle, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material.

[0118] Specifically, the pressure of the air (compressed air) output from the compressor 31 is set to 0.3 MPa, and the air flowing through the dispersion gas flow path 32 at a flow rate of 250 L / min is heated to 200° C. by the dispersion gas heater 33, and the air is supplied from the dispersion gas flow path 32 to the dispersion section 11 (collision-type high-speed airflow dispersion unit). On the other hand, the slurry is introduced into the dispersion section 11 from the slurry flow path 17 at a rate of 8 g / min, and the slurry is dispersed on the coated particles whose surfaces are attached with the coating liquid in the form of a film. In addition, the coated particles whose surfaces are attached with the coating liquid in the form of a film are flowed into the drying container 41 of the drying section 13, and the coating liquid attached to the surface of each coated particle is dried in the drying container 41, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material.

[0119] Then, the dry gel powder is collected by the collecting part 14 and calcined at a predetermined temperature to obtain a positive electrode active material powder in which lithium cobalt oxide as coated particles is coated with a lithium niobate thin film.

[0120] In Example 2, the mixing ratio was 32:1, the heat ratio was 2.5:1, and the solid-liquid ratio of the slurry was 2:1. In Example 2, no powder adhered to the inner surface of the drying container 41, no aggregated particles were generated, and no reaggregation of the temporarily dispersed coated particles was observed.

[0121] <Example 3>

[0122] 2.5 kg of coating liquid was added to a 15 L container with a stirring blade. While stirring with the stirring blade, 5 kg of lithium cobalt oxide (LiCoO2) with an average particle size of 5 μm as the coated particles (positive electrode active material) was added, and the slurry was obtained after stirring for several minutes.

[0123] use Figure 2 The coating device of the structure shown disperses the slurry onto the coated particles whose surfaces are adhered to by the coating liquid in the form of a film, and dries the coating liquid adhered to the surface of each coated particle, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material.

[0124] Specifically, the pressure of the air (compressed air) output from the compressor 31 is set to 0.3 MPa, and the air flowing through the dispersion gas flow path 32 at a flow rate of 2000 L / min is heated to 200° C. by the dispersion gas heater 33, and the air is supplied from the dispersion gas flow path 32 to the dispersion section 111 (Laval type high-speed airflow dispersion unit). On the other hand, the slurry is introduced into the dispersion section 111 from the slurry flow path 17 at a speed of 240 g / min, and the slurry is dispersed on the coated particles whose surfaces are attached with the coating liquid in the form of a film. In addition, the coated particles whose surfaces are attached with the coating liquid in the form of a film are flowed into the drying container 41 of the drying section 13, and the coating liquid attached to the surface of each coated particle is dried in the drying container 41, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material. Then, the dry gel powder is collected by the collecting part 14 and calcined at a predetermined temperature to obtain a positive electrode active material powder in which lithium cobalt oxide as coated particles is coated with a lithium niobate thin film.

[0125] In Example 3, the mixing ratio was 15:1, the heat ratio was 1.3:1, and the solid-liquid ratio of the slurry was 2:1. In Example 3, no powder adhered to the inner surface of the drying container 41, no aggregated particles were generated, and no reaggregation of the temporarily dispersed coated particles was observed.

[0126] <Comparative Example>

[0127] 2.3 kg of coating liquid was added to a 15 L container with a stirring blade. While stirring with the stirring blade, 5 kg of lithium cobalt oxide (LiCoO2) with an average particle size of 5 μm as the coated particles (positive electrode active material) was added, and the slurry was obtained after stirring for several minutes.

[0128] use Figure 2 The coating device of the structure shown disperses the slurry onto the coated particles whose surfaces are adhered to by the coating liquid in the form of a film, and dries the coating liquid adhered to the surface of each coated particle, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material.

[0129] Specifically, the pressure of the air (compressed air) output from the compressor 31 is set to 0.2 MPa, and the air flowing through the dispersion gas flow path 32 at a flow rate of 1500 L / min is heated to 180°C by the dispersion gas heater 33, and the air is supplied from the dispersion gas flow path 32 to the dispersion section 111 (Laval type high-speed airflow dispersion unit). On the other hand, the slurry is introduced into the dispersion section 111 from the slurry flow path 17 at a speed of 240 g / min, and the slurry is dispersed on the coated particles whose surfaces are attached with the coating liquid in the form of a film. In addition, the coated particles whose surfaces are attached with the coating liquid in the form of a film are flowed into the drying container 41 of the drying section 13, and the coating liquid attached to the surface of each coated particle is dried in the drying container 41, thereby obtaining a dry gel powder in which the surface of each coated particle is coated with the precursor of the coating material. Then, the dry gel powder is collected by the collecting part 14 and calcined at a predetermined temperature to obtain a positive electrode active material powder in which lithium cobalt oxide as coated particles is coated with a lithium niobate thin film.

[0130] In the comparative example, the mixing ratio was 15:1, the heat ratio was 0.8:1, and the solid-liquid ratio of the slurry was 2:1. In the comparative example, the powder adhered to the inner surface of the drying container 41, and aggregated particles were generated. In addition, reaggregation of the temporarily dispersed coated particles was observed.

[0131] <Conclusion>

[0132] Table 1 summarizes the contents (numerical values, etc.) of Examples 1 to 3 and Comparative Examples.

[0133]

Table 1

[0134] project Example 1 Example 2 Example 3 Comparative Example Mixing ratio 80 32 15 15 Heat Ratio 6 2.5 1.3 0.8 Dispersion air volume (L / min) 320 250 2000 1500 Dispersion air temperature (℃) 200 200 200 180 Slurry flow rate (g / min) 8 8 240 240 Distributed Collision Collision Laval Laval Particle generation results good good good Adhesion and aggregation

[0135] By comparing Examples 1 to 3 with the comparative example, it can be understood that when the heat ratio is less than 1:1, that is, when the heat of the air flowing into the dispersion section 11 per unit time is less than the heat required to evaporate the solvent from the coating liquid flowing into the dispersion section 11 per unit time, the dispersibility of the dry gel powder is low, for example, the powder adheres to the inner surface of the drying container 41 and generates aggregated particles, and in addition, the temporarily dispersed coated particles re-aggregate, etc.

Claims

1. A coating device, characterized in that: include: a mixed material flow path in which a mixed material formed by mixing the coated particles with a coating liquid formed by dissolving the coating material in a solvent flows; a dispersion gas source for outputting dispersion gas; a dispersion gas flow path in which the dispersion gas output from the dispersion gas source flows; a dispersion gas heating source for heating the dispersion gas flowing in the dispersion gas flow path; a dispersion section having a dispersion passage connected to the mixed material flow passage and the dispersion gas flow passage, the mixed material flows from the mixed material flow passage into the dispersion passage, the dispersion gas heated by the dispersion gas heating source flows from the dispersion gas flow passage into the dispersion passage, and the mixed material is dispersed onto the coated particles to which the coating liquid is attached in a film form by the airflow of the dispersion gas; and Control Department, The control unit controls the dispersion gas source so that the ratio of the weight of the dispersion gas flowing into the dispersion passage to the weight of the coated particles flowing into the dispersion passage is 3:1 or more.

2. The coating device according to claim 1, characterized in that: The control unit controls at least one of the dispersion gas source and the dispersion gas heating source so that the temperature of the dispersion gas flowing into the dispersion passage becomes equal to or higher than the boiling point of the solvent.

3. The coating device according to claim 2, characterized in that: The control unit controls at least one of the dispersion gas source and the dispersion gas heating source so that the heat of the dispersion gas flowing into the dispersion passage per unit time is greater than or equal to the heat required to evaporate the solvent from the mixed material flowing into the dispersion passage per unit time.

4. A coating device, characterized in that: include: a mixed material flow path in which a mixed material formed by mixing the coated particles with a coating liquid formed by dissolving the coating material in a solvent flows; a dispersion gas source for outputting dispersion gas; a dispersion gas flow path in which the dispersion gas output from the dispersion gas source flows; a dispersion gas heating source for heating the dispersion gas flowing in the dispersion gas flow path; a dispersion section having a dispersion passage connected to the mixed material passage and the dispersion gas passage, wherein the mixed material flows from the mixed material passage into the dispersion passage, and the dispersion gas heated by the dispersion gas heating source flows from the dispersion gas passage into the dispersion passage, and the mixed material is dispersed onto the coated particles to which the coating liquid is attached in a film form by the airflow of the dispersion gas; as well as Control Department, The control unit controls at least one of the dispersion gas source and the dispersion gas heating source so that the heat of the dispersion gas flowing into the dispersion passage per unit time is greater than or equal to the heat required to evaporate the solvent from the mixed material flowing into the dispersion passage per unit time.

5. The coating device according to any one of claims 1 to 4, characterized in that: The control unit controls the dispersion gas source so that the pressure of the dispersion gas outputted from the dispersion gas source is 0.15 MPa or more.

6. The coating device according to any one of claims 1 to 4, characterized in that: The mixed material is adjusted to a solid-liquid ratio of 2:0.5-3.

7. The coating device according to any one of claims 1 to 4, characterized in that: The particles to be coated are particles having an average particle diameter in the range of 100 nm or more and 50 μm or less.

8. The coating device according to any one of claims 1 to 4, characterized in that: Also includes: a drying gas flow path through which the drying gas flows; as well as The drying section has a drying passage connected to the drying gas flow passage, and dries the coating liquid attached to the coated particles flowing into the drying passage from the dispersion passage by the drying gas flowing into the drying passage from the drying gas flow passage.

9. The coating device according to claim 8, characterized in that: Also includes: The dry gas heating source heats the dry gas flowing through the dry gas flow path.

10. A coating method, characterized in that: A mixed material formed by mixing the particles to be coated with a coating liquid formed by dissolving the coating material in a solvent flows from the mixed material flow path into the dispersion path, Outputting a dispersion gas from a dispersion gas source to a dispersion gas flow path connected to the dispersion passage, The dispersed gas flowing in the dispersed gas flow path is heated by a dispersed gas heating source. The mixed material is dispersed on the particles to be coated with the coating liquid attached in a film form by the flow of the dispersion gas flowing from the dispersion gas flow path into the dispersion passage, The ratio of the weight of the dispersion gas flowing into the dispersion passage to the weight of the coated particles flowing into the dispersion passage is 3:1 or more.

11. The coating method according to claim 10, characterized in that: The temperature of the dispersion gas flowing into the dispersion passage is set to be equal to or higher than the boiling point of the solvent.

12. The coating method according to claim 11, characterized in that: The amount of heat of the dispersion gas flowing into the dispersion passage per unit time is made greater than or equal to the amount of heat required to evaporate the solvent from the mixed material flowing into the dispersion passage per unit time.

13. A coating method, characterized in that: A mixed material formed by mixing the particles to be coated with a coating liquid formed by dissolving the coating material in a solvent flows from the mixed material flow path into the dispersion path, Outputting a dispersion gas from a dispersion gas source to a dispersion gas flow path connected to the dispersion passage, The dispersed gas flowing in the dispersed gas flow path is heated by a dispersed gas heating source. The mixed material is dispersed on the particles to be coated with the coating liquid attached in a film form by the flow of the dispersion gas flowing from the dispersion gas flow path into the dispersion passage, The amount of heat of the dispersion gas flowing into the dispersion passage per unit time is made greater than or equal to the amount of heat required to evaporate the solvent from the mixed material flowing into the dispersion passage per unit time.

14. The coating method according to any one of claims 10 to 13, characterized in that The pressure of the dispersion gas outputted from the dispersion gas source is set to be 0.15 MPa or more.

15. The coating method according to any one of claims 10 to 13, characterized in that The mixed material is adjusted to a solid-liquid ratio of 2:0.5-3.

16. The coating method according to any one of claims 10 to 13, characterized in that: The particles to be coated are particles having an average particle diameter in the range of 100 nm or more and 50 μm or less.

17. The coating method according to any one of claims 10 to 13, characterized in that The coating liquid attached to the coated particles in a film form is dried.

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