Jet mill capable of removing static electricity and method of pulverizing sulfide-based solid electrolyte using the same

Abstract

To provide: a jet mill capable of removing static electricity which facilitates particle size control and increases pulverizing efficiency by removing static electricity inside a milling main body where pulverizing is performed; and a method of pulverizing a sulfide-based solid electrolyte using the same.SOLUTION: In a jet mill capable of removing static electricity according to the present disclosure, a raw material is fed into a hollow milling main body through a predetermined raw material supply pipe from a raw material supply unit, the raw materials are pulverized by collision with each other due to a strong jet air sprayed from an air nozzle installed in the milling main body when the raw materials fed into the above milling main body fill the milling main body to a predetermined height or higher, and upper and lower portions of the milling body are grounded to remove static electricity inside the milling main body.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a jet mill capable of removing static electricity and a method for pulverizing a sulfide-based solid electrolyte using the same, and more particularly to a jet mill capable of removing static electricity in a mill body where pulverization is performed, thereby easily adjusting particle size and improving pulverization efficiency, and a method for pulverizing a sulfide-based solid electrolyte using the same. [Background technology]

[0002] Recently, the use of secondary batteries in electronic devices such as smartphones has become common. A secondary battery has lithium as a positive electrode, is charged by lithium ions that move from the positive electrode to the negative electrode, and generates electricity by discharging in the process in which lithium moves from the negative electrode to the positive electrode.

[0003] Such lithium secondary batteries have the advantages of high energy density and the ability to achieve a long life, and therefore are commonly used in a variety of electronic devices. Recently, demand for such batteries has been expanding in line with the rapid growth of the electric vehicle market.

[0004] However, such lithium secondary batteries use an organic solvent as an electrolyte for ion migration, and therefore there is a risk of accidents occurring due to electrolyte leakage or evaporation, posing a safety problem.

[0005] In recent years, solid electrolyte technology that uses solid sulfide-based compounds as an alternative to conventional liquid electrolytes has been developed. Since only lithium ions move within the electrolyte, no side reactions occur, and the technology has the advantage of being extremely safe and durable.

[0006] Among the solid electrolytes used in lithium secondary batteries, the compound represented by Li7-XPS6-xClx has a cubic argyrodite-type crystal structure and has high ionic conductivity and electrochemical stability over a wide temperature range, so it is attracting attention as a sulfide-based solid electrolyte for mass production.

[0007] After synthesis, the solid electrolyte is milled to produce particles having a certain size. In the conventional milling process for solid electrolytes, a ball mill is generally used. However, such a ball mill not only requires several tens of hours of processing to produce particles of less than 10 μm required for solid electrolyte particles, but also has problems such as the formation of carbon compounds due to the reaction of the solvent, which reduces electrical conductivity.

[0008] Accordingly, in order to control the particle size of the solid electrolyte, a method of dry pulverization of particles using a jet mill has been adopted recently. FIG. 1 is a diagram showing a schematic diagram of a conventional jet mill, and FIG. 2 is a diagram for explaining the process by which a raw material is pulverized in the conventional jet mill.

[0009] As shown in FIG. 1, a conventional jet mill includes a raw material supply section 10, a mill body 20, a cyclone 30, a back filter 40, and a blower 50. A jet mill configured in this manner pulverizes the raw material through the process shown in FIG.

[0010] That is, a) raw material is fed from the raw material supply section 10 into the hollow mill body 20 through a specified raw material supply pipe 12, b) when the raw material fed into the inside of the mill body 20 is filled above a specified height, the raw materials are crushed as they collide with each other due to a strong jet airflow ejected from the air nozzle 24a provided at the bottom of the mill body 20, c) the crushed raw material particles rise due to the airflow, and particles having a particle size below a certain size pass through the classifying wheel 26a, while particles having a particle size above a certain size descend again to the bottom of the mill body 20 along the wall surface inside the mill body 20, and d) the particles that pass through the classifying wheel 26a move to the product collection section.

[0011] Incidentally, unexplained reference numeral 28 denotes a first product transfer pipe (connecting the classifying wheel 26a and the cyclone 30), and reference numeral 32 denotes a second product transfer pipe (connecting the cyclone 30 and the back filter 40). In this manner, in a conventional jet mill, high-pressure air is sprayed through the air nozzle 24a to cause collisions between pulverized particles, thereby obtaining particles having a desired size.

[0012] Jet mills are primarily used when grinding sulfide-based solid electrolytes (LPSC1), and are useful for adjusting the particle size to the desired size using only air. However, when grinding using such a conventional jet mill, static electricity is generated inside the mill body 20, and due to the ductile properties of the solid electrolyte, the particles clump together and adhere to the walls inside the mill body 20. This makes it difficult to control the particle size when pulverizing the solid electrolyte, resulting in a problem of reduced pulverization efficiency. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been devised to solve the above-mentioned problems of the related art, and an object of the present invention is to provide a static electricity-removing jet mill, which can easily adjust particle size and improve grinding efficiency by removing static electricity in the mill body where grinding is performed, and a grinding method for sulfide-based solid electrolytes using the same. [Means for solving the problem]

[0014] In order to achieve the above-mentioned objects, a jet mill capable of removing static electricity according to a first aspect of the present invention is a jet mill configured such that raw materials are fed from a raw material supply section through a specified raw material supply pipe into the interior of a hollow mill body, and when the raw materials fed into the interior of the mill body fill above a specified height of the mill body, a strong jet air stream is sprayed from an air nozzle provided in the mill body, causing the raw materials to collide with each other and be pulverized, and characterized in that the top and bottom of the mill body are grounded to remove static electricity within the mill body.

[0015] A concave lower plate is positioned horizontally at the bottom within the mill body, and the air nozzles have a plurality of air nozzles spaced apart from one another along the edge of the lower plate, the plurality of air nozzles being arranged toward the center of the lower plate. The bottom plate is made of ceramic.

[0016] A cover is provided at the open upper end of the mill body, and a classifying wheel is provided inside the cover. An upper plate is arranged horizontally at the top of the mill body, and one or more raw material inlet holes are formed in the upper plate along the circumferential direction, penetrating vertically, so that raw material supplied from the raw material supply pipe is introduced into the raw material inlet holes.

[0017] The top plate is made of ceramic. The raw material supply pipe is provided with a designated ionizer, and by simultaneously supplying raw material to the raw material inlet hole of the upper plate and supplying ionized air, it is possible to prevent the raw material from stagnating on the upper plate.

[0018] In addition, a pulverization method for a sulfide-based solid electrolyte using a jet mill capable of removing static electricity according to a second aspect of the present invention uses a jet mill configured such that a sulfide-based solid electrolyte is introduced from a raw material supply unit through a predetermined raw material supply pipe into a hollow mill body, and when the sulfide-based solid electrolyte introduced into the inside of the mill body is filled to a predetermined height or more, a strong jet stream is sprayed from an air nozzle provided at the bottom of the mill body, causing the sulfide-based solid electrolyte to collide with each other and be pulverized, and at this time, the upper and lower parts of the mill body are grounded to remove static electricity within the mill body.

[0019] In addition, the raw material supply pipe is provided with a predetermined ionizer, so that the sulfide-based solid electrolyte can be supplied to the inside of the mill body while ionized air is also supplied. Details of other embodiments are set forth in the Detailed Description and accompanying Drawings.

[0020] The advantages and / or features of the present invention, as well as the method for achieving the same, will become apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the configurations of the embodiments disclosed below, but can be modified and embodied in various different forms. However, the embodiments disclosed in this specification are provided for the purpose of complete disclosure of the present invention and are provided so that a person having ordinary knowledge in the technical field to which the present invention belongs can fully understand the scope of the present invention. It should be understood that the present invention is defined by the scope of the claims set forth in the claims. Effect of the Invention

[0021] According to the means for solving the above-mentioned problems, the present invention has the following effects. According to the present invention, by grounding the top and bottom of the mill body and removing static electricity from within the mill body, it is possible to prevent the problem of raw material particles, such as sulfide-based solid electrolytes, clumping together and adhering to the walls of the mill body.

[0022] This removes static electricity from within the mill body where the grinding takes place, making it easier to adjust the particle size. In addition, according to the present invention, a specified ionizer is provided in the raw material supply pipe, and raw materials are supplied to the raw material inlet hole of the upper plate located inside the mill body while ionized air is also supplied. This prevents raw materials such as sulfide-based solid electrolytes from remaining on the upper plate due to static electricity, thereby improving milling efficiency and productivity. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of a conventional jet mill. [Diagram 2] FIG. 1 is a diagram for explaining a process in which raw material is pulverized in a conventional jet mill. [Diagram 3] FIG. 2 is a schematic diagram of a mill body in a jet mill according to the present invention. [Figure 4] FIG. 2 shows an upper plate disposed inside the mill body in the jet mill according to the present invention. [Diagram 5] FIG. 2 is a diagram showing a lower plate disposed at the lower part of the mill body in the jet mill according to the present invention. [Figure 6] FIG. 2 is a view showing a cover of a mill body in the jet mill according to the present invention. [Figure 7] 1 is a photograph comparing an upper plate in a mill body of a jet mill according to the present invention (Example) with an upper plate in a mill body of a jet mill according to a conventional technology (Comparative Example), and a graph showing the results of particle size analysis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, preferred embodiments of the jet mill capable of removing static electricity and the method for pulverizing a sulfide-based solid electrolyte using the same according to the present invention will be described in detail with reference to the accompanying drawings. Incidentally, the terms and words used in this specification and claims should not be interpreted in a limited manner based on their ordinary or dictionary meanings, but should be interpreted based on the meaning and concept that matches the technical idea of ​​the present invention, in accordance with the principle that the inventor can appropriately define the concept of the term in order to best describe his / her invention. In addition, the embodiments described in this specification and the configurations shown in the drawings are merely preferred embodiments of the present invention, and do not fully represent the technical idea of ​​the present invention, so it should be understood that there may be various equivalents and modifications that can replace them at the time of this application.

[0025] FIG. 3 is a schematic diagram showing a mill body in the jet mill according to the present invention. The jet mill capable of removing static electricity according to the present invention is configured so that raw materials are fed from the raw material supply section through a specified raw material supply pipe 12 into the hollow mill body 20, and when the raw materials fed into the mill body 20 fills up to a specified height or above, a strong jet stream is sprayed from the air nozzle 24a provided at the bottom of the mill body 20, causing the raw materials to collide with each other and be pulverized.

[0026] In this case, the raw material may be a sulfide-based solid electrolyte. Such a sulfide-based solid electrolyte is a type of inorganic solid electrolyte. Inorganic solid electrolytes are generally classified into oxide-based and sulfide-based types.

[0027] Sulfide-based solid electrolytes have been widely studied as promising materials in the development of next-generation all-solid-state batteries, and like liquid electrolytes, they have the advantages of high ionic conductivity, low mechanical deformation and low weight density.

[0028] When raw materials such as the sulfide-based solid electrolyte are fed into the inside of the mill body 20, static electricity is generated, and due to the ductile properties of the solid electrolyte, the particles may clump together and adhere to the walls inside the mill body 20.

[0029] Therefore, in the present invention, the upper and lower parts of the mill body 20 are grounded to remove static electricity within the mill body 20, thereby making it possible to easily adjust the particle size and improve the grinding efficiency. The mill body 20 has a cylindrical shape having a cavity, and one end of the raw material supply pipe 12 is connected to one side surface of the mill body 20 so as to communicate with the inside of the mill body 20 .

[0030] In addition, an upper plate 22 is arranged horizontally on the upper side within the mill body 20, a lower plate 24 is arranged horizontally on the lower side within the mill body 20, and a cover 26 is arranged on the open upper end of the mill body 20 to seal the upper part of the mill body 20.

[0031] Furthermore, a designated ionizer 14 is provided in the raw material supply pipe 12, and by supplying raw material through the raw material inlet hole of the upper plate 22 located at the top inside the mill body 20 and simultaneously supplying ionized air, it is possible to prevent raw material particles that have solidified together due to static electricity from remaining on top of the upper plate 22.

[0032] FIG. 4 is a diagram showing an upper plate disposed inside the mill body in the jet mill according to the present invention. An upper plate 22 is disposed horizontally on the upper side within the mill body 20 . In this case, the outer peripheral surface of the upper plate 22 has a shape corresponding to the inner peripheral surface of the mill body 20, and when the upper plate 22 is placed inside the mill body 20, an airtight state is maintained between the outer peripheral surface of the upper plate 22 and the inner peripheral surface of the mill body 20.

[0033] For example, the upper plate 22 may be disk-shaped and the interior of the mill body 20 may be cylindrical. Such upper plate 22 has one or more raw material feeding holes 22a formed vertically along the circumferential direction, and raw material supplied from the raw material supply pipe 12 is fed into the raw material feeding holes 22a, filling the inside of the mill body 20 to a predetermined height.

[0034] When the inside of the mill body 20 is filled with raw materials to a predetermined height or more, the raw materials are crushed while colliding with each other by a strong jet stream ejected from the air nozzle 24a. Such a top plate 22 may be made of ceramic.

[0035] FIG. 5 is a diagram showing a lower plate disposed at the lower part of the mill body in the jet mill according to the present invention. A lower plate 24 having a concave shape (inclined downward from the edge toward the inside) is positioned horizontally at the bottom inside the mill body 20 .

[0036] A plurality of air nozzles 24 a may be provided radially and spaced apart along the edge of such a lower plate 24 , and the air outlets of the air nozzles 24 a may be arranged to face the center of the lower plate 24 . The raw material fed into the inside of the mill body 20 through the raw material feeding hole 22a formed in the upper plate 22 descends to the lower plate 24 and fills the inside of the mill body 20 up to a predetermined height. When the raw material fills above the predetermined height, the raw material particles are pulverized by a strong jet stream sprayed from the air nozzle 24a. The lower plate 24 may be made of ceramic.

[0037] FIG. 6 is a diagram showing a cover of the mill body in the jet mill according to the present invention. A cover 26 is provided at the open upper end of the mill body 20 to seal the upper part of the mill body 20 . A classifying wheel 26a may be provided on the inside of such a cover 26 (on the side facing the inside of the mill body 20 when the mill body 20 is sealed with the cover 26).

[0038] Inside the mill body 20, the raw material particles are pulverized by the strong jet airflow sprayed from the air nozzle 24a, and rise with the airflow. If the particle size is below a certain size, the particles pass through the classifying wheel 26a and then move to the product collection section.

[0039] Furthermore, if the particle size of the raw material particles is equal to or larger than a certain size, the raw material particles will travel along the wall surface of the mill body 20 and then descend again to the lower part of the mill body 20, where they will be pulverized by the jet stream.

[0040] FIG. 7 is a photograph comparing an upper plate in the mill body of a jet mill according to the present invention (Example) with an upper plate in the mill body of a jet mill according to the prior art (Comparative Example), and a graph showing the results of particle size analysis.

[0041] The ionizer 14 installed in the raw material supply pipe 12 is intended to remove static electricity from the air being supplied, and is provided to prevent the static electricity of the raw material fed into the inside of the mill body 20 from causing the raw material particles to clump together, clogging the raw material feeding hole 22a in the upper plate 22, and causing such clumped particles to remain on the upper plate 22.

[0042] When ionized air is supplied by the ionizer 14, the retention of the raw material on the upper plate 22 is improved, and as shown in the upper right photograph (example) in FIG. 7, it can be seen that the raw material does not retain in the area where the ionized air is supplied.

[0043] The upper left photograph in FIG. 7 (comparative example) shows a case where the raw material accumulates on the upper plate and the raw material inlet hole becomes clogged, as in the conventional case. When the raw material no longer accumulates above the upper plate 22, the raw material ground at the bottom of the mill body 20 is carried by the rising air current and smoothly moved (classified) through the classifying wheel 26a located at the top, thereby improving the grinding efficiency and productivity.

[0044] Furthermore, the bottom part of Figure 7 shows the results of a PSA (Particle Size Analyzer), which shows the maximum particle size (D max ) was atomized from 22.00 μm (Comparative Example) to 13.08 μm (Example), and the yield (g / h) was greatly improved from 300 g / h (Comparative Example) to 600 g / h (Example).

[0045] The present invention as described above is not limited to the above-described embodiments and the accompanying drawings, and it will be easily understood by those having ordinary knowledge in the technical field to which the present invention pertains that various substitutions, modifications, and changes can be made within the scope that does not deviate from the technical idea of ​​the present invention. [Explanation of symbols]

[0046] 10: Raw material supply department 12: Raw material supply pipe 14: Ionizer 20: Mill body 22: Upper plate 24: Lower plate 24a: Air nozzle 26: Cover 26a: Classification wheel 28: First product transfer pipe 30: Cyclone 32: Second product transfer pipe 40: Bag filter 50: Blower

Claims

1. A jet mill configured such that raw materials are fed from a raw material feed section through a predetermined raw material feed pipe into a hollow mill body, and when the raw materials fed into the mill body reach a predetermined height or higher of the mill body, a strong jet stream is sprayed from an air nozzle provided in the mill body, causing the raw materials to collide with each other and be pulverized, A jet mill capable of removing static electricity, characterized in that the upper and lower parts of the mill body are grounded to remove static electricity within the mill body.

2. A concave lower plate is horizontally positioned on the lower side of the mill body, The air nozzle includes a plurality of air nozzles spaced apart from one another along an edge of the lower plate, The jet mill capable of removing static electricity according to claim 1 , wherein the plurality of air nozzles are arranged so as to face toward a center of the lower plate.

3. 3. The jet mill capable of removing static electricity according to claim 2, wherein the lower plate is made of ceramic.

4. 2. The static electricity removing jet mill according to claim 1, wherein a cover is provided on the open upper end of the mill body, and a classifying wheel is provided inside the cover.

5. 2. The jet mill capable of removing static electricity as described in claim 1, wherein an upper plate is horizontally arranged on the upper side of the mill body, and one or more raw material input holes are formed in the upper plate and penetrate vertically along the circumferential direction, and the raw material supplied from the raw material supply pipe is input into the raw material input holes.

6. 6. The jet mill capable of removing static electricity according to claim 5, wherein the upper plate is made of ceramic.

7. 2. The jet mill capable of removing static electricity as described in claim 1, wherein a predetermined ionizer is provided in the raw material supply pipe, and the raw material is supplied to the raw material inlet hole of the upper plate while ionized air is simultaneously supplied, thereby preventing the raw material from remaining on the upper plate.

8. A method for pulverizing a sulfide-based solid electrolyte using a jet mill, the method being configured such that a sulfide-based solid electrolyte is introduced from a raw material supply unit through a predetermined raw material supply pipe into a hollow mill body, and when the sulfide-based solid electrolyte introduced into the mill body fills the mill body to a predetermined height or more, a strong jet stream is sprayed from an air nozzle provided at a lower part of the mill body, causing the sulfide-based solid electrolyte to collide with each other and be pulverized, A method for pulverizing a sulfide-based solid electrolyte using a jet mill capable of removing static electricity, characterized in that the upper and lower parts of the mill body are grounded to remove static electricity within the mill body.

9. 9. The method for pulverizing a sulfide-based solid electrolyte using a jet mill capable of removing static electricity according to claim 8, wherein a predetermined ionizer is provided in the raw material supply pipe, and the sulfide-based solid electrolyte is supplied into the inside of the base mill body while ionized air is simultaneously supplied thereto.

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