CN111536775A - System and method for drying metal powder using negative pressure - Google Patents
System and method for drying metal powder using negative pressure Download PDFInfo
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- CN111536775A CN111536775A CN201910429609.3A CN201910429609A CN111536775A CN 111536775 A CN111536775 A CN 111536775A CN 201910429609 A CN201910429609 A CN 201910429609A CN 111536775 A CN111536775 A CN 111536775A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B11/00—Machines or apparatus for drying solid materials or objects with movement which is non-progressive
- F26B11/12—Machines or apparatus for drying solid materials or objects with movement which is non-progressive in stationary drums or other mainly-closed receptacles with moving stirring devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B21/00—Arrangements or duct systems, e.g. in combination with pallet boxes, for supplying and controlling air or gases for drying solid materials or objects
- F26B21/005—Drying-steam generating means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
- F26B25/005—Treatment of dryer exhaust gases
- F26B25/007—Dust filtering; Exhaust dust filters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B25/00—Details of general application not covered by group F26B21/00 or F26B23/00
- F26B25/04—Agitating, stirring, or scraping devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B5/00—Drying solid materials or objects by processes not involving the application of heat
- F26B5/04—Drying solid materials or objects by processes not involving the application of heat by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum
Abstract
Systems and methods for drying metal powders using negative pressure are disclosed. The system comprises: a drying apparatus comprising: a drying furnace, one side of which is fed with raw metal powder; and a heating chamber which is provided around the outer periphery thereof in a state of being spaced apart from the drying furnace and heats the drying furnace; a raw material input device which is connected to the upper part of the drying furnace and inputs the raw material metal powder into the drying furnace; a stirring device installed in the drying furnace and stirring the raw material metal powder input into the drying furnace; a driving device installed at an upper portion of the drying device and providing a speed to the stirring device; a steam device which supplies steam into the heating chamber; a bag filter installed at an upper portion of the drying furnace, sucking the raw metal powder and the steam, discharging the steam, and dropping the raw metal powder into the drying furnace; a condenser connected to one side of the bag filter and drying air by converting the discharged steam into water; and a vacuum pump for bringing the drying furnace into a negative pressure state by forming a vacuum pressure.
Description
Technical Field
The present disclosure relates to a system and method for drying metal powder, and more particularly, to a system and method for drying metal powder using negative pressure for manufacturing improved rechargeable batteries.
Background
Rechargeable batteries, which can be recharged, are widely used in various types of mobile devices, such as smart phones, laptops, tablets, and MP3 players. In addition, rechargeable batteries are also used as important power sources for mobile vehicles such as electric vehicles and electric bicycles.
Metal powders made of lithium, nickel, cobalt, aluminum, etc. are required to produce rechargeable batteries. In particular, it is known that the purity of the raw material metal powder affects the life of the rechargeable battery and the electrical quality with respect to charge and discharge, and the quality deteriorates as the amount of moisture or impurities increases.
Therefore, quality management is thoroughly performed to prevent moisture and other impurities from being mixed with metal powder made of lithium, nickel, cobalt, aluminum, etc. in the apparatus for producing rechargeable batteries to the maximum extent. In particular, since the raw metal powder is in contact with air during the production or transportation of the raw metal powder, a small amount of moisture (about 4 to 12 wt%) is inevitably contained in the raw metal powder, which needs to be removed during a pretreatment process of a main process for manufacturing a rechargeable battery.
In the drying process for removing moisture, it is necessary to avoid mechanical contact between the raw metal powder and the drying device and physical contact between machines in the drying device to the maximum extent. This is because other metal particles can be mixed with the metal powder having high purity due to mechanical contact or physical contact. Therefore, there is a need for research and development of a pretreatment process capable of manufacturing a high-quality rechargeable battery by maximally avoiding mechanical and physical contact with a drying device while removing a small amount of moisture contained in the raw material metal powder.
Disclosure of Invention
The present disclosure is directed to providing a system and method for drying metal powder for manufacturing an improved rechargeable battery using negative pressure, which is capable of removing moisture from raw metal powder while maximally inhibiting impurities from being mixed with the raw metal powder for manufacturing a rechargeable battery.
The present invention is also directed to further increasing the temperature in the drying device, which is increased as it is heated by the steam, by forming a vacuum pressure in the drying device. The present disclosure is also directed to providing a system and method for drying metal powder for manufacturing an improved rechargeable battery using negative pressure, which is capable of removing moisture from raw metal powder using only low-temperature steam.
A system for drying metal powder used to manufacture an improved rechargeable battery using negative pressure according to an exemplary embodiment of the present disclosure, the system comprising: a drying device, the drying device comprising: a drying furnace, one side of which is fed with raw material metal powder for manufacturing a rechargeable battery; and a heating chamber which is provided around an outer periphery of the drying furnace in a state of being spaced apart from the drying furnace and heats the drying furnace; a raw material input device which is connected to an upper portion of the drying furnace and inputs the raw material metal powder into the drying furnace; a stirring device installed in the drying furnace and stirring the raw material metal powder input into the drying furnace; a driving device installed at an upper portion of the drying device and providing a speed to the stirring device; a steam device that supplies steam into the heating chamber; a bag filter installed at an upper portion of the drying furnace, sucking the raw metal powder and steam in the drying furnace, discharging the steam, and dropping the raw metal powder into the drying furnace; a condenser connected to one side of the bag filter and drying air by converting the steam discharged from the bag filter into water; and a vacuum pump for bringing the drying furnace into a negative pressure state by forming a vacuum pressure.
In an exemplary embodiment, the upper portion of the drying oven may have a hemispherical dome structure so as to support the load of the driving means and prevent deformation caused by the vacuum pressure.
In an exemplary embodiment, a steam discharge port for discharging steam supplied from the steam device may be formed in a lower surface of the heating chamber.
In an exemplary embodiment, the driving device may include: a first motor generating a first speed to be supplied to the stirring device to dry the raw metal powder; a second motor that generates a second speed higher than the first speed, and the second speed is supplied to the stirring device to discharge the raw metal powder; a clutch axially coupled to the first motor and the second motor, the clutch operating when the first speed is generated and preventing the first speed from being transmitted to the second motor; and a drive shaft having one side axially coupled to the clutch and the other side axially coupled to the stirring device and transmitting the first speed or the second speed to the stirring device.
In an exemplary embodiment, the first speed may be 0.5 to 1RPM, and the second speed may be 2 to 10 RPM.
In an exemplary embodiment, the vacuum pump may exhaust steam from the drying furnace by creating a vacuum pressure in the drying furnace, and further increase the temperature of the drying furnace increased by the steam in the heating chamber by the vacuum pressure.
The system for drying metal powder for manufacturing an improved rechargeable battery using negative pressure according to an exemplary embodiment of the present disclosure may further include: one or more sensors installed in the drying oven to measure moisture in the drying oven and to measure temperature and weight of the drying oven; a discharging device provided at a lower portion of a side surface of the drying furnace; a vibrator conveying device that conveys the mixed metal powder discharged by the discharging device; a control unit that controls the steam device, the driving device, the discharging device, and the raw material input device based on a humidity signal, a temperature signal, and a weight signal measured by the sensor; a water tank connected to the condenser and storing water generated from the condenser; and an air filter filtering air discharged from the condenser.
As a technical method for achieving the above object, a method of drying metal powder for manufacturing an improved rechargeable battery using negative pressure according to an exemplary embodiment of the present disclosure includes a first step of inputting raw material metal powder for manufacturing a rechargeable battery to one side of a drying furnace by means of a raw material input device; a second step of drying the raw material metal powder by means of steam supplied from a steam device to a heating chamber while stirring the raw material metal powder in the drying furnace by a stirring device and a driving device; a third step of sucking the raw metal powder and steam in the drying furnace into a bag filter by means of a negative pressure of a vacuum pump during the second step, discharging the steam to a condenser connected to the bag filter, and dropping the raw metal powder into the drying furnace through the bag filter; a fourth step of drying the air by converting the steam sucked into the condenser into water; a fifth step of discharging the mixed metal powder completely stirred in the drying furnace by means of a discharging device; and a sixth step of conveying the mixed metal powder discharged from the discharge device to the outside by means of a conveying device.
The second step may include a first step of the second step of heating and drying the drying oven by means of heat transfer of steam supplied to the heating chamber; a second step of the second step of forming a negative pressure in the drying furnace by means of the vacuum pump; a third step of the second step of stirring the raw material metal powder by rotating the stirring device at a first speed; and a fourth step of the second step of stopping the operation of the vacuum pump so as to generate an air flow in the drying furnace.
In the second step, the drying oven may be heated in a temperature range of 100 ℃ to 120 ℃ by heat transfer of steam, and in the third step, the internal temperature in the negative pressure may be increased to a temperature range of 160 ℃ to 180 ℃.
The air dried by means of the condenser in the fourth step may be discharged from the condenser after the moisture content becomes 10% or less.
According to the exemplary embodiments of the present disclosure, it is possible to remove even a very low concentration of moisture in the raw metal powder while maximally suppressing impurities from being mixed with the raw metal powder for manufacturing a rechargeable battery. Therefore, a high-quality rechargeable battery can be produced.
In addition, moisture in the raw material metal powder can be removed by further raising the temperature in the drying furnace heated by steam using vacuum pressure during the drying of the raw material metal powder and using only low-temperature steam.
Drawings
The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
fig. 1 is a complete schematic diagram of a metal powder drying system for manufacturing an improved rechargeable battery using negative pressure according to an exemplary embodiment of the present disclosure;
FIG. 2 is an enlarged cross-sectional view showing the drying apparatus and components located at the periphery of the drying apparatus in FIG. 1;
FIG. 3 is a top plan view of the drying apparatus shown in FIG. 1;
FIG. 4 is a cross-sectional view of the drive device shown in FIG. 1;
fig. 5 is a block diagram illustrating a configuration in which a control unit performs a control operation according to an exemplary embodiment of the present disclosure;
fig. 6 is a flowchart illustrating a metal powder drying method for manufacturing an improved rechargeable battery using negative pressure according to an exemplary embodiment of the present disclosure; and
fig. 7 is a flowchart showing details of the raw metal powder stirring and drying step shown in fig. 6.
Description of the reference numerals
10: control unit
50: raw material input device
60: raw metal powder
100: drying device
110: drying furnace
111: upper part of drying furnace
113: lower part of drying furnace
115: coupling unit
120: heating chamber
121: steam inlet
123: baffle plate
125: steam outlet
130: manhole (manhole)
135: spring balancer
140: supporting member
150: insulating cover
160: sensor with a sensor element
200: steam device
300: stirring device
310: stirring shaft
320: stirring blade
400: drive device
410: the first motor
420: second motor
430: clutch device
440: drive shaft
450: bearing assembly
460: oil seal
470: air purging pipe
480: supporting member
490: speed reducer
500: discharge device
510: discharge unit
520: discharge port
600: conveying device
650: mixed metal powder
700: bag filter
750: steam generating device
800: condenser
810: water (W)
830: air (a)
900: water tank
1000: air filter
1100: vacuum pump
Detailed Description
Drying system
Hereinafter, a metal powder drying system (hereinafter, referred to as a "drying system") for manufacturing an improved rechargeable battery using negative pressure according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.
The drying system according to the exemplary embodiment of the present disclosure includes the drying device 100, and further includes a raw material input device 50, a steam device 200, a stirring device 300, a driving device 400, an exhaust device 500, a conveying device 600, a bag filter 700, a condenser 800, a water tank 900, an air filter 1000, and a vacuum pump 1100. In addition, the drying system according to the exemplary embodiment of the present disclosure may further include necessary components.
The raw material input device 50 is installed at one side of the drying device 100, and inputs the raw material metal powder 60 into the drying device 100 according to a control command of the control unit 10 to manufacture a predetermined number of rechargeable batteries. As the raw material input device 50, a screw feeder, a rotary feeder, a vibrator feeder, or the like may be applied.
The stirring device 300 is installed in the drying device 100, and the drying device 100 uniformly dries the raw material metal powder 60 by heating the raw material metal powder 60 at a high temperature while the raw material metal powder 60 input into the drying device 100 is stirred by the stirring device 300. The drying apparatus 100 includes a drying oven (or drying box) 110, a heating chamber 120, a manhole 130, a support member 140, an insulation cover 150, and a sensor 160.
The raw material input means 50, the driving means 400, and the bag filter 700 are installed at the upper portion 111 of the drying furnace 110. The raw material metal powder 60 is fed from the raw material feeder 50 to the lower portion 113 of the drying furnace 110. In addition, the upper portion 111 of the drying furnace and the lower portion 113 of the drying furnace are coupled to each other by a coupling unit 115, and the drying furnace 110 has a sealing structure when the upper portion 111 and the lower portion 113 are coupled to each other. Further, the pressure in the drying furnace 110 enters a negative pressure state due to the vacuum pressure applied from the vacuum pump 1100. In this case, the vacuum pressure applied to the drying oven 110 causes the outer shape of the drying oven 110 to be deformed. To solve this problem, the upper portion 111 of the drying oven 110 has a hemispherical dome structure. The above-described dome structure of the upper portion 111 of the drying furnace not only prevents deformation caused by vacuum pressure, but also supports the load of the raw material input means 50, the driving means 400, and the bag filter 700 installed at the upper portion 111.
The heating chamber 120 is installed around the outer circumference of the lower portion 113 of the drying furnace 110 to be adjacent to the lower portion 113 of the drying furnace 110 in a state where the heating chamber 120 is spaced apart from the lower portion 113 of the drying furnace 110. Further, the heating chamber 120 heats the drying oven 110 by using the steam inputted from the steam device 200. The heating chamber 120 is installed adjacent to the lower portion 113 of the drying oven in a state of being spaced apart from the lower portion 113 of the drying oven so that the steam in the heating chamber 120 heats the drying oven 110 by heat transfer. That is, the steam does not come into direct contact with the raw metal powder 60. Further, the heating chamber 120 has a steam inlet 121, a baffle plate 123, and a steam discharge port 125.
One or more steam inlets 121 are provided at one side of the heating chamber 120. Further, the steam inlet 121 is connected to the steam device 200 and allows steam to be input into the heating chamber 120. Further, the steam inlet 121 may be provided in the form of a pipe and connected to the heating chamber 120 and the steaming device 200.
One or more baffles 123 are provided in the heating chamber 120 in a state where the baffles 123 have an inclination angle. The baffle 123 guides the steam inputted from one side of the heating chamber 120 so that the steam is diffused to the other side of the heating chamber 120. That is, the inclination angle of the baffle 123 may be understood as an angle at which the diffusion of the vapor may be induced.
One or more steam discharge ports 125 are provided in a lower surface of the heating chamber 120 to discharge steam in the heating chamber 120 from the heating chamber 120. The steam discharge port 125 may include a pipe and a valve, and the pipe and the valve are operated according to a control command of the control unit 10.
One or more manholes 130 are provided in a lower surface of the insulation cover 150 to discharge the steam discharged through the steam discharge port 125 to the outside. The manhole 130 is opened or closed by means of a spring balancer 135, and steam is discharged to the outside when the manhole 130 is opened. In addition, the spring balancer 135 operates to open or close the manhole 130 according to a control command of the control unit 10. Meanwhile, the steam discharged from the manhole 130 may be supplied to a heating medium boiler (not shown) connected to the drying device 100.
The support member 140 has a base frame 141 installed at a lower portion of the insulation cover 150 and supporting the drying device 100, and one or more reinforcement members 142 installed in the insulation cover 150 and supporting the drying device 100. Here, the base frame 141 is provided in the form of an "H" beam, and the reinforcing member 142 may be welded to the insulation cover 150.
The reinforcing member 142 is installed in the insulating cover 150, and the insulating cover 150 is installed around the outer circumferences of the drying oven 110 and the heating chamber 120 and protects the drying oven 110 and the heating chamber 120 from external impact. For this, the insulating cover 150 may be made of a rubber or silicone material.
One or more sensors 160 are installed in the drying oven 110 to measure moisture in the drying oven 110 and to measure the temperature and weight of the drying oven 110. A single sensor 160 may measure all of the moisture, temperature, and weight, or the sensor 160 may include a moisture sensor, a temperature sensor, and a weight sensor. Further, the moisture signal, the temperature signal, and the weight signal measured by the sensor 160 are transmitted to the control unit 10, and the control unit 10 controls the drying process based on the measured moisture, the measured temperature, and the amount of the measured weight. As a specific example related to the control of the drying process, the control unit 10 first determines whether to continue or end the drying process based on the moisture amount measured by the sensor 160. After the determination, the control unit 10 controls the amount of steam supplied by the steam device 200 based on the temperature measured by the sensor 160. After controlling the amount of steam, the control unit 10 detects a weight change of the drying furnace 110 based on the weight measured by the sensor 160, and controls whether or not the raw material metal powder 60 is input from the raw material input device 50.
The steam device 200 is connected to the heating chamber 120 via the steam inlet 121 and supplies steam to the heating chamber 120. The steam device 200 is not limited to a device for generating steam. For example, a device for delivering steam generated from a heating medium (not shown) used in a heating medium boiler (not shown) to the heating chamber 120 may be substituted for the steam device 200.
The stirring device 300 is installed at the center of the upper portion of the drying device 100, and stirs the raw material metal powder 60 while rotating by the driving device 400. For this, the stirring device 300 includes a stirring shaft 310 and a stirring blade 320.
The agitating shaft 310 is vertically installed at the center of the drying furnace 110, the lower end of the agitating shaft 310 is installed, and the upper end of the agitating shaft 310 is connected to the shaft of the driving device 400, so that the agitating shaft 310 rotates by receiving a speed from the driving device 400.
The agitating blade 320 is installed at the lower end of the agitating shaft 310 in a state where the agitating blade 320 is slightly spaced apart from the inner bottom of the lower portion 113 of the drying furnace. The stirring blade 320 uniformly mixes the raw material metal powder 60 input to the drying furnace 110 as the stirring shaft 310 rotates. Further, the stirring blade 320 has an inclination angle such that the stirring blade 320 pushes the raw material metal powder 60 outward toward the outer circumferential edge thereof while rotating. This structure makes it easy to discharge the mixed metal powder 650 that is completely stirred.
The driving device 400 has a first motor 410, a second motor 420, a clutch 430, and a drive shaft 440 to provide speed to the stirring device 300 to dry and discharge the raw metal powder 60.
The first motor 410 generates a first speed, which is the speed at which the raw metal powder 60 is dried. Here, the first speed is 0.5 to 1RPM, and is used when removing moisture contained in the raw material metal powder 60 while stirring the raw material metal powder 60.
The second motor 420 generates a second speed, which is a speed at which the raw material metal powder 60 is discharged. Here, the second speed is 2 to 10RPM, is higher than the first speed, and is used when the raw material metal powder 60 is discharged to the outside by pushing the raw material metal powder 60 outward toward the outer circumference of the lower portion 113 of the drying furnace.
The clutch 430 is axially coupled to the first and second motors 410 and 420 and the driving shaft 440, and transmits the first and second speeds to the driving shaft 440 or prevents the first and second speeds from being transmitted to the driving shaft 440. In an exemplary embodiment of the present disclosure, the clutch 430 is provided as an air clutch, a pneumatic clutch, or a hydraulic clutch. Further, the clutch 430 operates when the first speed is generated, thereby preventing the first speed from being transmitted to the second motor 420. The reason why the clutch 430 is provided as described above is to prevent the first speed from affecting the second motor 420 provided between the first motor 410 and the driving shaft 440.
One side of the drive shaft 440 is axially coupled to the clutch 430 and the other side of the drive shaft 440 is axially coupled to the agitator shaft 310 such that the drive shaft 440 transmits the first speed or the second speed to the agitator shaft 310. The structure of the driving shaft 440 may include a horizontal driving shaft horizontally installed and axially coupled to the clutch 430, and a vertical driving shaft vertically installed and axially coupled to the stirring shaft 310.
Meanwhile, the driving apparatus 400 according to the exemplary embodiment of the present disclosure further includes a bearing 450, an oil seal 460, an air purge pipe 470, a support member 480, and a speed reducer 490.
The bearing 450 surrounds the outside of the drive shaft 440 to support the drive shaft 440 against impact, the drive shaft 440 rotating at a first or second speed.
An oil seal 460 is installed adjacent to the driving shaft 440 in the housing and prevents leakage of the input oil, thereby allowing the driving shaft 440 to smoothly rotate.
An air purge tube 470 is installed in the housing to remove air and moisture remaining in the housing, and a drive shaft 440 passes through the inside of the housing.
The support member 480 is installed at a lower portion of the first motor 410 and a lower portion of the second motor 420 to support loads of the first motor 410 and the second motor 420.
The discharging device 500 is disposed at a lower portion of a side of the drying furnace 110, and includes a discharging unit 510 and a discharging pipe 520, and the discharging unit 510 and the discharging pipe 520 are configured to discharge the completely dried mixed metal powder 650 from the drying furnace 110.
The discharge unit 510 discharges the completely dried mixed metal powder 650 to the discharge pipe 520. The discharge unit 510 includes a cylinder and a piston, which are horizontally installed at a lower portion of the side of the drying furnace 110. In addition, the exhaust unit 510 opens or closes the lower portion of the side of the drying furnace 110 as the piston reciprocates. Further, the discharge unit 510 is configured to allow the mixed-metal powder 650 pushed outward toward the outer periphery by the stirring blade 320 to fall into the discharge pipe 520 when the discharge unit 510 is opened. Further, the discharge unit 510 operates according to a control instruction of the control unit 10.
The discharge pipe 520 is connected to the discharge unit 510, and discharges the mixed metal powder 650 falling into the discharge unit 510 from the drying furnace 110 to the conveying device 600.
The conveying device 600 is connected to the discharge pipe 520 and conveys the discharged mixed-metal powder 650 to a subsequent process. In the case of using the screw feeder, impurities are likely to be mixed with the metal powder due to friction between the metal screw and the metal powder. Therefore, a vibrator feeder (vibration feeder) that can avoid contact with the metal to the maximum extent can be used. The conveyor 600 conveys three tons of metal powder at a time.
The bag filter 700 is vertically installed at the upper portion 111 of the drying oven. The bag filter 700 discharges the steam 750 including high-temperature air and moisture generated in the drying oven 110 to the outside. However, the bag filter 700 drops the fine metal particles mixed with the steam 750 into the drying furnace 110, thereby returning the fine metal particles to the drying furnace 110. Since the detailed internal configuration of the bag filter 700 is well known, a detailed description thereof will be omitted.
The condenser 800 is connected to one side of the bag filter 700 and dries the air 830 included in the steam 750, while converting the steam 750 discharged from the bag filter 700 into water 810. The condenser 800 operates according to a control instruction of the control unit 10.
The water tank 900 is connected to one side of the condenser 800 and stores water 810 generated by the condenser 800. The water tank 900 operates to be opened or closed according to a control command of the control unit 10, and discharges the water 810 to the outside.
The air filter 1000 is connected to the other side of the condenser 800 and filters air 830 discharged from the condenser 800. The air filter 1000 is replaced or cleaned according to a control instruction of the control unit 10.
The vacuum pump 1100 forms a vacuum pressure in the drying oven 110 so that the drying oven 110 is in a negative pressure state. Even after the temperature in the drying furnace 110 is increased by the steam in the heating chamber 120, the temperature in the drying furnace 110 is further increased by the vacuum pressure. Therefore, the drying furnace 110 dries the mixed-metal powder 650 more quickly than the case where the mixed-metal powder 650 is dried only by the steam of the heating chamber 120. Further, the air and moisture in the drying oven 110 are evaporated due to the steam 750 and then discharged from the drying oven 110 into the bag filter 700 due to the vacuum pressure. Meanwhile, the vacuum pump 1100 operates according to a control instruction of the control unit 10.
The control unit 10 is connected to and controls the raw material input device 50, the drying device 100, the steaming device 200, the stirring device 300, the driving device 400, the discharging device 500, the conveying device 600, the bag filter 700, the condenser 800, the water tank 900, the air filter 1000, and the vacuum pump 1100. A representative embodiment of the control unit 10 may include a microcomputer, a CPU, or the like, and the control unit 10 may be configured as a computer including a microcomputer, a CPU, or the like.
Drying method
Hereinafter, a metal powder drying method (hereinafter, referred to as "drying method") for manufacturing an improved rechargeable battery using negative pressure according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.
First, a raw material metal powder 60 for manufacturing a rechargeable battery is input to one side of the drying furnace 110 via the raw material input device 50 (S100). Here, the raw material metal powder 60 is a metal powder including at least one of lithium, nickel, cobalt, and aluminum. In addition, the raw metal powder 60 typically contains 4 to 12 wt% moisture during the manufacturing process. In the case where the raw material metal powder 60 contains a large amount of moisture, there is a problem in that a drying process requires a large amount of time, so that the entire process cannot be smoothly performed.
In this case, as the raw material metal powder 60 is input into the drying furnace 110, the weight of the drying furnace 110 increases. Further, the sensor 160 detects an increase in weight of the drying oven 110 and transmits the detected increase amount to the control unit 10. In this case, when the weight of the drying furnace 110 exceeds the reference weight, the control unit 10 stops the raw material input device 50 to cut off the input of the raw material metal powder 60.
Next, the raw material metal powder 60 is dried by means of the steam supplied from the steam device 200 to the heating chamber 120 while the raw material metal powder 60 is stirred by the stirring device 300, and the stirring device 300 is rotated in the drying furnace 110 at a speed provided by the driving device 400 (S200). That is, the first speed (0.5 to 1RPM) of the first motor 410 for drying the raw metal powder 60 is transmitted to the stirring shaft 310, so that the stirring blade 320 rotates. The raw metal powder 60 is slowly and uniformly pushed outward toward the outer periphery of the lower portion 113 of the drying furnace by the rotation. Further, steam in a temperature range of 100 to 120 ℃ is generated by the steam device 200 and then supplied to the heating chamber 120.
In step S200, the drying oven 110 is heated and dried by heat transfer of the steam supplied to the heating chamber 120 (S210). Here, the steam of the heating chamber 120 is the steam supplied from the steam device 200 as described above, and the drying furnace 110 is heated in a temperature range of 100 ℃ to 120 ℃ by heat transfer of the steam. Further, since the heating chamber 120 is installed adjacent to the drying furnace 110 in a state where the heating chamber 120 is spaced apart from the drying furnace 110, the raw material metal powder 60 input into the drying furnace 110 is not directly dried by the steam.
Next, the vacuum pump 1100 forms a vacuum pressure in the drying furnace 110 (S220). In this case, the pressure in the drying oven 110 enters a negative pressure state due to the vacuum pressure applied from the vacuum pump 1100. In addition, the internal temperature in the drying furnace 110 is further increased from a temperature of 100 ℃ to 120 ℃ to a temperature of 160 ℃ to 180 ℃. Here, since the drying time increases and the internal temperature in the drying furnace 110 further increases, if the temperature is 20 ℃ or less, economic feasibility may be deteriorated due to low temperature. In addition, if the temperature exceeds 180 ℃, an excessive amount of steam is supplied and the pressure of the steam is too high, which may cause the risk of explosion and the change in physical properties. Therefore, a temperature range of 120 ℃ to 180 ℃ is suitable, and when the drying process is performed for 3 hours, a temperature range of 130 ℃ to 150 ℃ is more suitable. The temperature may be maintained at the temperature detected by the sensor 160 and then transmitted to the control unit 10.
Meanwhile, in the vacuum pressure forming step S220, the steam 750 containing air and moisture and the raw metal powder 60 are sucked into the bag filter 700 by means of the vacuum pressure of the vacuum pump 1100. In this case, the steam 750 is discharged to the outside, the raw metal powder 60 falls into the drying furnace 110 while being filtered by the bag filter 700, and then the raw metal powder 60 is returned. Therefore, the loss of the metal powder caused by the discharge of the steam during the drying process can be minimized.
Next, the stirring blade 320 stirs the raw material metal powder 60 while rotating at the first speed (S230). The stirring step S230 may be performed together with the vacuum pressure forming step S220. In this case, the agitator shaft 310 receives a first speed from the first motor 410, and the first speed is 0.5 to 1RPM as described above. That is, the stirring blade 320 stirs the raw material metal powder 60 while rotating at the first speed by the stirring shaft 310. At the same time, the raw material metal powder 60 is gradually and uniformly pushed outward toward the outer peripheral edge of the lower portion 113 of the drying furnace by stirring.
Next, the operation of the vacuum pump 1100 is stopped so that the air flow is generated in the drying oven 110 (S240). In this case, when the air flow is generated in the drying oven 110, the negative pressure state is released. Further, when the control unit 10 determines that the moisture content of the raw material metal powder 60 detected by means of the sensor 160 is 600ppm or less, the air generation step S240 is performed. That is, the vacuum pump 1100 continuously forms the vacuum pressure, and the drying furnace 110 is maintained in the negative pressure state until the moisture content of the raw material metal powder 60 becomes 600ppm or less.
After steps S210 to S240 are ended, the pressure in the drying furnace 110 becomes negative pressure due to the vacuum pressure of the vacuum pump 1100, and the raw material metal powder 60 and the steam 750 are sucked into the bag filter 700. Then, the steam 750 is discharged to the condenser 800 connected to the bag filter 700, and the bag filter 700 drops the raw material metal powder 60 into the drying furnace 110 (S300). That is, fine metal particles (raw metal powder) that may be contained in the steam 750 sucked into the bag filter 700 are filtered out by the bag filter 700, naturally fall, and then are returned to the drying furnace 110. Therefore, the loss of the metal powder caused by the discharge of the steam during the drying process can be minimized.
Further, in the suction and separation step S300, as the drying oven 110 enters a negative pressure state due to the vacuum pressure of the vacuum pump 1100, the internal temperature in the drying oven 110 further rises. That is, the drying furnace 110 is heated in a temperature range of 100 ℃ to 120 ℃ by heat transfer of steam. In addition, as the drying furnace 110 enters a negative pressure state due to the vacuum pressure in the suction and separation step S300, the internal temperature in the drying furnace 110 is further increased to a temperature range of 160 ℃ to 180 ℃. As described above, the temperature in the drying furnace 110 is further increased in the suction and separation step S300 because if the temperature in the drying furnace 110 is 120 ℃ or less, the drying time is increased due to the low temperature and the economic feasibility is deteriorated. In addition, if the temperature exceeds 180 ℃, an excessive amount of steam is supplied and the pressure of the steam is too high, which may cause the risk of explosion and the change in physical properties. Therefore, a temperature range of 120 ℃ to 180 ℃ is suitable, and when the drying process is performed for 3 hours, a temperature range of 130 ℃ to 150 ℃ is more suitable. The temperature may be maintained when the sensor 160 detects the temperature and then transmits it to the control unit 10.
Next, when the control unit 10 determines that the moisture content of the raw material metal powder 60 detected by the sensor 160 is 600ppm or less, the control unit 10 stops the suction and separation step S300. When the suction and separation step S300 is stopped, the supply of steam from the steam device 200 is stopped.
Next, the steam 750 sucked into the condenser 800 is converted into water 810 (S400). That is, when the steam 750 discharged from the drying oven 110 is sucked by vacuum pressure, the condenser 800 converts the steam 750 into water 810 based on a drying process. The drying process of the condenser 800 is performed until the moisture in the air 830 contained in the steam 750 becomes 10% or less, and when the moisture 830 in the air becomes 10% or less, the air 830 is discharged to the air filter 1000. The condenser 800 may have a sensor (not shown) that may measure moisture in the air 830 to perform the drying process. Meanwhile, a drying process is performed to prevent the vacuum pump 1100 from being damaged by moisture contained in the air 830 discharged from the condenser 800 and then passing through the air filter 1000.
Next, the condenser 800 discharges the water 810 to the water tank 900 according to a control command of the control unit 10. Further, the water tank 900 stores water 810 discharged from the condenser 800. Further, the condenser 800 discharges the air 830 to the air filter 1000 according to a control instruction of the control unit 10. In addition, the air filter 1000 filters air discharged from the condenser 800. In this case, the air filtered by the air filter 1000 is discharged to the outside via the vacuum pump 1100.
Next, the mixed metal powder 650 completely stirred in the drying furnace 110 is discharged by means of the discharging device 500 (S500). Specifically, the exhaust unit 510 opens the lower portion of the side of the drying oven 110. Further, the second speed (2 to 10RPM) of the second motor 420 is transferred to the stirring shaft 310 so that the stirring blade 320 pushes the mixed metal powder 650 outward toward the outer circumference of the drying furnace 110 while rotating at a speed higher than the first speed. As described above, the mixed-metal powder 650 pushed outward toward the outer periphery of the drying furnace 110 falls down by the discharge unit 510 and is conveyed to the conveying device 600 via the discharge pipe 520.
Next, the mixed-metal powder 650 discharged from the discharging device 500 is conveyed by the conveying device 600 (S600). Here, in the case where a screw feeder is used for the conveying device 600, impurities are likely to be mixed with the metal powder due to friction between the metal screw and the metal powder. Therefore, a vibrator feeder (vibration feeder) that can avoid contact with the metal to the maximum extent can be used.
Meanwhile, in the exemplary embodiments of the present disclosure, it has been described that: the process of the steam conversion and water generation step S400 and then the mixed metal powder discharge step S500 is performed, but the order of the steps is determined only for convenience of description, and the steam conversion and water generation step S400 and the mixed metal powder discharge step S500 may be performed simultaneously.
Cross Reference to Related Applications
The present application claims priority from korean patent application No. 10-2019-0014378 filed by the korean intellectual property office at 7.2.2019 and korean patent application No. 10-2019-0014907 filed by the korean intellectual property office at 8.2.2019, the disclosures of which are incorporated herein by reference.
Claims (11)
1. A system for drying metal powder used to make improved rechargeable batteries using negative pressure, the system comprising:
a drying device, the drying device comprising: a drying furnace, one side of which is fed with raw material metal powder for manufacturing a rechargeable battery; and a heating chamber which is provided around an outer periphery of the drying furnace in a state of being spaced apart from the drying furnace and heats the drying furnace;
a raw material input device which is connected to an upper portion of the drying furnace and inputs the raw material metal powder into the drying furnace;
a stirring device installed in the drying furnace and stirring the raw material metal powder input into the drying furnace;
a driving device installed at an upper portion of the drying device and providing a speed to the stirring device;
a steam device that supplies steam into the heating chamber;
a bag filter installed at an upper portion of the drying furnace, sucking the raw metal powder and steam in the drying furnace, discharging the steam, and dropping the raw metal powder into the drying furnace;
a condenser connected to one side of the bag filter and drying air by converting the steam discharged from the bag filter into water; and
a vacuum pump that brings the drying furnace into a negative pressure state by forming a vacuum pressure.
2. The system of claim 1, wherein an upper portion of the drying oven has a hemispherical dome structure so as to support a load of the driving means and prevent deformation caused by the vacuum pressure.
3. The system according to claim 1, wherein one steam discharge port for discharging the steam supplied from the steam device is formed in a lower surface of the heating chamber.
4. The system of claim 1, wherein the drive means comprises:
a first motor generating a first speed to be supplied to the stirring device to dry the raw metal powder;
a second motor that generates a second speed higher than the first speed, and the second speed is supplied to the stirring device to discharge the raw metal powder;
a clutch axially coupled to the first motor and the second motor, the clutch operating when the first speed is generated and preventing the first speed from being transmitted to the second motor; and
a drive shaft axially coupled to the clutch on one side and to the stirring device on the other side and transmitting the first speed or the second speed to the stirring device.
5. The system of claim 4, wherein the first speed is 0.5 to 1RPM and the second speed is 2 to 10 RPM.
6. The system of claim 1, wherein the vacuum pump exhausts steam from the drying oven by creating a vacuum pressure in the drying oven and further increasing the temperature of the drying oven increased by the steam in the heating chamber with the vacuum pressure.
7. The system of claim 1, further comprising:
one or more sensors installed in the drying oven to measure moisture in the drying oven and to measure temperature and weight of the drying oven;
a discharging device provided at a lower portion of a side surface of the drying furnace;
a vibrator conveying device that conveys the mixed metal powder discharged by the discharging device;
a control unit that controls the steam device, the driving device, the discharging device, and the raw material input device based on a humidity signal, a temperature signal, and a weight signal measured by the sensor;
a water tank connected to the condenser and storing water generated from the condenser; and
an air filter filtering air discharged from the condenser.
8. A method of drying a metal powder for use in the manufacture of an improved rechargeable battery using negative pressure, the method comprising:
a first step of inputting raw material metal powder for manufacturing a rechargeable battery to one side of a drying furnace by means of a raw material input device;
a second step of drying the raw material metal powder by means of steam supplied from a steam device to a heating chamber while stirring the raw material metal powder in the drying furnace by a stirring device and a driving device;
a third step of sucking the raw metal powder and steam in the drying furnace into a bag filter by means of a negative pressure of a vacuum pump during the second step, discharging the steam to a condenser connected to the bag filter, and dropping the raw metal powder into the drying furnace through the bag filter;
a fourth step of drying the air by converting the steam sucked into the condenser into water;
a fifth step of discharging the mixed metal powder completely stirred in the drying furnace by means of a discharging device; and
a sixth step of conveying the mixed metal powder discharged from the discharge device to the outside by means of a conveying device.
9. The method of claim 8, wherein the second step comprises:
a first step of the second step of heating and drying the drying oven by means of heat transfer of steam supplied to the heating chamber;
a second step of the second step of forming a negative pressure in the drying furnace by means of the vacuum pump;
a third step of the second step of stirring the raw material metal powder by rotating the stirring device at a first speed; and
a fourth step of the second step of stopping the operation of the vacuum pump so as to generate an air flow in the drying furnace.
10. The method according to claim 8, wherein in the second step the drying oven is heated in a temperature range of 100 ℃ to 120 ℃ by means of heat transfer of steam, and in the third step the internal temperature in the negative pressure is raised to a temperature range of 160 ℃ to 180 ℃.
11. The method according to claim 8, wherein the air dried by means of the condenser in the fourth step is discharged from the condenser after the moisture content becomes 10% or less.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR10-2019-0014378 | 2019-02-07 | ||
| KR1020190014378A KR102069461B1 (en) | 2019-02-07 | 2019-02-07 | Metal powders drying device for cell battery manufacturing and drying method Thereof |
| KR10-2019-0014907 | 2019-02-08 | ||
| KR1020190014907A KR102069462B1 (en) | 2019-02-08 | 2019-02-08 | Metal powders drying system for improved secondary cell battery manufacturing using negative pressure and drying method Thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111536775A true CN111536775A (en) | 2020-08-14 |
Family
ID=71943765
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910429609.3A Pending CN111536775A (en) | 2019-02-07 | 2019-05-22 | System and method for drying metal powder using negative pressure |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN111536775A (en) |
| PL (1) | PL240378B1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115451662A (en) * | 2022-09-02 | 2022-12-09 | 大连北方互感器集团有限公司 | Vacuum drying operation process of silicon micropowder pre-drying system |
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Also Published As
| Publication number | Publication date |
|---|---|
| PL240378B1 (en) | 2022-03-21 |
| PL430053A1 (en) | 2020-08-10 |
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