Apparatus and method for uniformly distributing powder materials using IPL

Abstract

An apparatus and method for processing powder materials using IPL is disclosed. The powder material processing apparatus according to the present invention includes a chamber, a mother powder input line through which mother powder having a polymer coating is input into the chamber, a gas injector disposed at the bottom of the chamber for injecting air upward to suspend the mother powder within the chamber, an IPL irradiator for carbonizing the polymer coating of the mother powder, and a treated powder discharge line through which the treated powder with the carbonized polymer coating is discharged out of the chamber.

Description

[Technical Field]

[0001] The present invention relates to a technique for producing powders such as anode / cathode powders for lithium secondary batteries.

[0002] More particularly, the present invention relates to an apparatus and method for processing powder materials using Intense Pulsed Light (IPL). [Background technology]

[0003] Demand for lithium secondary batteries, such as lithium-ion batteries, is increasing due to their wide range of applications, from small and portable electronic products to large electric vehicles. The shift from fossil fuel-powered vehicles to electric vehicles is becoming more visible, which is driving interest in high-performance lithium secondary batteries. Various research efforts are underway to achieve higher capacity, longer life, faster charging, and greater safety for lithium secondary batteries, one of which is the development of anodes and cathodes with higher energy densities than currently available.

[0004] Silicon (Si), with a theoretical capacity of 4,200 mAh / g, has attracted attention as a candidate active material for the anode of lithium-based batteries due to its high energy density. For similar reasons, sulfur (S), with a theoretical capacity of 1,675 mAh / g, has also attracted attention as a candidate active material for the cathode of lithium-based batteries. However, silicon and sulfur are known to have high volume expansion rates during repeated lithiation processes. These rapid volume changes can lead to the crushing and exfoliation of the active materials, resulting in loss of electrode integrity and electrical insulation, and thus degrading battery performance.

[0005] In order to solve the problems related to the volume expansion rate of these active materials, methods of treating the surface of the active material have been proposed.

[0006] Korean Patent Publication No. 10-2014-0034879 (published on March 20, 2014) discloses a method of surface treating silicon particles with a polymer such as polyalkylene oxide. Coating the silicon particles with the polymer prevents damage caused by volume changes during charging and discharging.

[0007] However, simply coating silicon particles with a polymer does not provide structural rigidity to the silicon particles, and as a result, it is difficult to suppress the volume expansion of the silicon particles.

[0008] This requires that the inner portion of the polymer thickness remain in a polymeric state while the outer portion of the polymer thickness becomes rigid.

[0009] One possible method for hardening the outer portion of the polymer in the thickness direction is to coat the powder material with a polymer coating with carbon or metal, but this method requires an additional coating process, which is time-consuming and economical.

[0010] Another method for hardening the outer thickness of a polymer is to carbonize only the outer thickness of the polymer coating. This method may not require a separate coating process. However, using traditional heating methods, it is difficult to carbonize only the outer thickness of the polymer coating. Summary of the Invention [Problem to be solved by the invention]

[0011] The problem to be solved by the present invention is to provide a powder material processing device and method that can uniformly carbonize only the outer portion of the polymer coating in the thickness direction of a powder material having a polymer coating. [Means for solving the problem]

[0012] In order to solve the above problems, the powder material processing device according to the present invention includes a chamber, a raw powder input line through which raw powder having a polymer coating is input into the chamber, a gas injector disposed at the bottom of the chamber for injecting air upward to suspend the raw powder within the chamber, an IPL irradiator for carbonizing the polymer coating of the raw powder, and a processed powder output line through which the processed powder with the carbonized polymer coating is discharged out of the chamber.

[0013] The gas injector may inject air upward at an air pressure corresponding to the gravity acting on the mother powder so as to balance the gravity and buoyancy acting on the mother powder and suspend the mother powder at a specific height within the chamber, and the discharge line for the treated powder may be formed at a position higher than the specific height so that the treated powder, which has become lighter than the mother powder due to the carbonization, can be discharged outside the chamber by the gas injector.

[0014] The powder material processing device may further include a compressed air supply, which may be in fluid communication with the base powder input line and the gas injector.

[0015] The powder material processing device may further include powder counters disposed on the input line for the base powder and the discharge line for the processed powder, respectively.

[0016] A feedstock hopper may be disposed in the input line of the mother powder, or the input line of the mother powder may be connected to a discharge line of a mother powder storage device or a powder drying device.

[0017] The IPL irradiator may be disposed on a side surface or an upper surface of the chamber, and in this case, the powder material processing device may further include a reflector that covers all surfaces except for the irradiation surface of the IPL irradiator.

[0018] The IPL irradiator may be provided with an air flow path through which air passes.

[0019] The discharge line for the treated powder may be connected to or include a cyclone separator so that the air and the treated powder are separated from each other.

[0020] To achieve the above object, a method for processing powder material according to the present invention includes the steps of: introducing a base powder having a polymer coating into a chamber through which air is injected upward to suspend the base powder in the chamber; applying an IPL to the base powder to carbonize the polymer coating from its surface; and discharging the processed powder with the carbonized polymer coating from the chamber.

[0021] Air may be injected upward at an air pressure corresponding to the gravity acting on the mother powder so that the gravity acting on the mother powder and the buoyancy force are balanced and the mother powder is buoyed at a specific height in the chamber, and the treated powder, which has become lighter than the mother powder due to the carbonization, may be discharged from the chamber by the air pressure.

[0022] In one embodiment of the method, the method further comprises supplying compressed air in a compressed air supplier to the interior of the chamber to transport the base powder into the interior of the chamber and to inject air in an upward direction.

[0023] In one embodiment of the method, the method further comprises monitoring the number of base powders fed into the chamber and the number of treated powders discharged out of the chamber, respectively.

[0024] In one embodiment of the method, the method further comprises separating fine powder in the exhaust gas with an electrostatic precipitator before feeding the exhaust gas back into the compressed air supplier to form a closed loop system. [Effects of the Invention]

[0025] In the present invention, by applying IPL, which has a pulse duration of several milliseconds and can apply energy only to a limited depth from the surface of the polymer, it is possible to carbonize only the outer portion of the polymer coating in the thickness direction of the polymer coating powder material.

[0026] In particular, in the present invention, when the carbonization rate of the polymer reaches a target value, the polymer is prevented from further carbonization and is allowed to escape to the outside using air pressure and gravity, thereby providing uniform carbonization. Furthermore, these processes can be carried out in a continuous process. [Brief explanation of the drawings]

[0027] Referring to the drawings, various aspects of the present invention are shown in detail by way of example and not by way of limitation.

[0028] [Figure 1] 1A-1C are schematic diagrams illustrating examples of powder materials before and after carbonization. [Figure 2] 1 is a diagram illustrating a method for processing powder material according to the present invention; [Figure 3] FIG. 2 is a diagram schematically illustrating the magnitude of air pressure and gravity acting on the base powder before and after carbonization. [Figure 4] 1 is a schematic diagram of a powder material processing apparatus according to an embodiment of the present invention; [Figure 5] FIG. 10 is a schematic diagram illustrating a powder material processing apparatus according to another embodiment of the present invention. [Figure 6] FIG. 10 is a schematic diagram illustrating a powder material processing apparatus according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The following description and the embodiments described herein are provided as examples of principles of the present invention in its various forms. These embodiments are not intended to limit the present invention in its various forms, but are provided for illustrative purposes. Like reference numerals refer to like parts throughout the description and drawings. The drawings are not necessarily to scale, and in some cases proportions may be exaggerated to more clearly depict particular features.

[0030] FIG. 1 is a schematic diagram of an example of powder material before and after carbonization.

[0031] FIG. 1 illustrates a silicon powder used in anodes for lithium secondary batteries such as lithium ion batteries, lithium metal batteries, lithium sulfur batteries, and lithium air batteries, showing a base powder 100 before carbonization and a treated powder 200 after carbonization.

[0032] 1, the base powder 100 includes a core active material 110 and a polymer coating 120 on the surface of the core active material 110. If necessary, a carbon-based additive 130 may be dispersed in the polymer coating 120.

[0033] The base powder 100 having a polymer coating is partially or completely carbonized from the surface of the polymer coating 120 by application of intense pulsed light (IPL) to generate a treated powder 200. In Fig. 1, the treated powder 200 generated by partial carbonization of the surface of the polymer coating by application of IPL includes an outer shell 121 and an inner shell 122, and nanopores 125 are formed in the outer shell. The outer shell 121 may be hard and carbonized, and the inner shell 122 may be soft and not carbonized.

[0034] In the processed powder 200 of Figure 1, the outer shell 121 provides structural support and electrical conductivity, forming a thin and stable solid electrolyte interface. The inner shell 122 is filled with a relatively soft, non-carbonized polymer to reduce mechanical stress on the active material due to volumetric changes during lithiation and delithiation. The multiple nanopores 125 allow lithium ions to easily diffuse through.

[0035] FIG. 2 is a diagram showing a schematic diagram of a method for processing powder material according to the present invention.

[0036] Referring to FIG. 2, the method for processing powder material according to the present invention includes a step of introducing a mother powder (S210), a step of carbonizing a polymer coating using IPL (S220), and a step of discharging the processed powder (S230).

[0037] In the mother powder introduction step (S210), the mother powder 100 having a polymer coating is introduced into the chamber. Air is injected upward into the chamber, thereby suspending the mother powder having a polymer coating within the chamber. The mother powder having a polymer coating may be a dried powder, but is not necessarily limited to this. Alternatively, the mother powder may be in the form of droplets containing a solvent. In this case, the chamber to which the IPL is applied may further be equipped with a heating means such as a heater, thereby enabling both drying of the mother powder and carbonization of the polymer coating. Alternatively, the mother powder droplets may be dried in a drying chamber, and then the dried mother powder may be introduced into the chamber to which the IPL is applied.

[0038] Compressed air can be supplied to the interior of the chamber by a compressed air supply machine in order to transport the base powder 100 into the interior of the chamber and to spray air in an upward direction.

[0039] The number of mother powders 100 fed into the chamber can be monitored using a powder number counter.

[0040] In the polymer coating carbonization step (S220) using IPL, IPL is applied to the base powder 100 having a polymer coating, carbonizing the polymer coating from its surface to produce treated powder 200. The degree of carbonization of the polymer coating can be determined by the IPL application conditions. In the case of IPL, the pulse duration is several milliseconds, and energy is applied to a limited depth from the surface of the polymer coating, resulting in partial carbonization of the polymer coating. Of course, the pulse duration, pulse shape, and number of applications of IPL can be controlled to completely carbonize the polymer coating.

[0041] IPL uses fast-acting photoelectron waves generated by a xenon lamp. When high-intensity pulses of electricity are applied through a xenon gas-charged lamp, the xenon gas is excited to a higher energy state and then released to a lower state, generating photon radiation. This intense pulse of energy is also called a flash. IPL technology has advantages over other electromagnetic energy applications, such as lasers and microwaves, because it can cover a large surface area in a short time. IPL also has a broad pulsed light spectrum, typically ranging from 200 to 1100 nm. Modern IPL devices use computer-controlled capacitor banks to generate IPL, allowing for pulse duration, pulse interval, pulse number, and intensity to be manipulated. Fluence (the amount of radiant energy received by a surface per unit area) is related to the distance from the energy source to the target surface, the angle of the reflector, and the absorbance of the target surface.

[0042] The application of IPL is more suitable for powder treatments because IPL can irradiate a large surface area at once.

[0043] In the treated powder discharge step (S230), the treated powder 200 with the polymer coating partially or completely carbonized is discharged to the outside of the chamber. The number of treated powders 200 discharged to the outside of the chamber, as well as the number of base powders supplied to the inside of the chamber, can be monitored using a powder number counter.

[0044] FIG. 3 is a diagram schematically showing the magnitude of air pressure and gravity acting on the base powder before and after carbonization.

[0045] As shown in the example of Figure 3(a), when the gravity acting on the mother powder and the levitation force due to the air pressure are balanced, the mother powder is maintained suspended at a specific height within the chamber while rotating. That is, the mother powder with the polymer coating is maintained at a specific height by repeating slight rises and falls while rotating on its axis in the air due to the air pressure inside the chamber.

[0046] When the polymer coating is carbonized, components other than carbon are removed from the polymer coating, reducing the weight of the powder. As a result, the treated powder with the carbonized polymer coating is subjected to air pressure greater than gravity, and as a result, the treated powder can be expelled from the chamber by the air pressure.

[0047] In the present invention, the application of IPL can carbonize only the outer portion of the polymer coating powder material in the thickness direction of the polymer coating. In particular, in the present invention, when the carbonization rate of the polymer reaches a target value, the polymer is prevented from further carbonization and escapes to the outside using air pressure and gravity, thereby providing uniform carbonization.

[0048] If the air pressure is too high, the degree of carbonization of the powder may vary slightly depending on the spacing between the powder particles and the distance at which the IPL is applied. However, in the present invention, the balance between air pressure and gravity is used to prevent further carbonization of the polymer when the carbonization rate of the polymer reaches a target value, thereby achieving uniform carbonization of the polymer coating of the powder. For this reason, in the present invention, sufficient air pressure is applied to keep the powder suspended at a specific height.

[0049] FIG. 4 is a schematic diagram of a powder material processing apparatus according to an embodiment of the present invention.

[0050] Referring to FIG. 4, the powder material processing device according to the present invention includes a base powder supply device 410, a chamber 420, a gas injector 430, an IPL irradiator 440, and processing powder separation devices 450 and 470.

[0051] The mother powder supply device 410 is connected to the inlet 422 of the chamber 420 by a mother powder input line so that the mother powder having the polymer coating is supplied to the inside of the chamber. The mother powder supply device 410 may be in the form of a storage tank, a feedstock hopper, etc., or may be a powder drying device.

[0052] The chamber 420 is a space in which the base powder is treated by applying energy, and the interior surfaces of the chamber, except for the inlet 422, outlet 424, and IPL irradiator 440, may be composed of reflective surfaces that reflect light.

[0053] The gas injector 430 is disposed at the bottom of the chamber and is connected to the gas supply device 406. The gas supply device 406 connected to the gas injector 430 may also be connected to a mother powder supply device 410 that supplies the mother powder for transport. The gas injector 430 injects compressed gas upward inside the chamber to suspend the mother powder within the chamber. The gas may be air, argon, nitrogen, or the like.

[0054] The gas injector 430 can balance the gravity and levitation force acting on the base powder to levitate the base powder at a specific height in the chamber. To balance the gravity and levitation force acting on the base powder, the gas injector can inject gas upward with an air pressure corresponding to the gravity acting on the base powder.

[0055] The IPL irradiator 440 carbonizes the polymer coating of the base powder. A xenon lamp can be used as the IPL irradiator 440. The IPL irradiator 440 is electrically connected to an AC power supply 442, and an IPL power controller 444 may be disposed between the IPL irradiator 440 and the AC power supply 442.

[0056] 4 shows an example in which the IPL irradiator 440 is disposed at the top of the chamber 420 and the IPL is applied from top to bottom, but this is not limiting and the IPL irradiator may be disposed at the side or bottom of the chamber. The inner surface of the chamber may be configured as a reflective surface to increase the efficiency of IPL application.

[0057] In addition, the application of IPL may increase the temperature of the IPL irradiator 440, and an air flow path through which air passes may be provided in the IPL irradiator for cooling. The compressed air introduced into the chamber through the air flow path may cool the IPL irradiator as it passes through the air flow path inside the IPL irradiator.

[0058] An outlet 424 is formed through the chamber 420 to discharge the treated powder whose polymer coating has been carbonized. The outlet 424 may be formed at a position higher than a certain floating height so that the treated powder, which has become lighter than the base powder due to carbonization, can be discharged by air pressure provided by a gas injector 430.

[0059] The processed powder separators 450 and 470 separate the gas and the processed powder, respectively. The processed powder separators may be connected to or include the cyclone separator 450. The processed powder separators may also include an electrostatic precipitator 470 to separate fine powder that has not yet been separated from the gas by the cyclone separator 450. The processed powder separated by the processed powder separators may be stored in a powder storage device 460. The separated gas may be further supplied to a gas supply line from the gas supply device 406.

[0060] Meanwhile, the powder material processing device may further include a compressed gas supplier, i.e., compressor 407, a low-pressure regulator 408-1, and a high-pressure regulator 408-2. The low-pressure regulator 408-1 may be connected to a gas injector. The high-pressure regulator 408-2 may be connected to an inlet 422 of the chamber via a mother powder input line. The low-pressure regulator 408-1 and the high-pressure regulator 408-2 may provide compressed gas at different gas pressures to the inside of the chamber 420 via the inlet 422 and the gas injector 430.

[0061] 4, reference numeral 401 denotes a ball valve, reference numeral 402 denotes a ball valve in a mostly closed state, reference numeral 403 denotes a one-way check valve, reference numeral 404 denotes a threaded union, reference numeral 405 denotes a quick disconnect bleed port, and reference numeral 409 denotes a flow control valve. These elements are necessary for controlling the flow of gas and powder and for connecting each element.

[0062] FIG. 5 is a schematic diagram of a powder material processing apparatus according to another embodiment of the present invention.

[0063] Referring to Figure 5, the powder material processing device according to this embodiment includes a chamber 510, a mother powder input line 520 through which the mother powder is input into the chamber, a gas injector 530 for injecting gas into the chamber, an IPL irradiator 540 for irradiating the chamber with IPL 545, a processed powder discharge line 550 for discharging the processed powder from the chamber, and a gas supply device 560 for supplying compressed gas to the mother powder input line and the gas injector.

[0064] The chamber 510, gas injector 530, and IPL irradiator 540 in the powder material processing apparatus shown in Figure 5 can be substantially similar to the chamber 420, gas injector 430, and IPL irradiator 440 shown in Figure 4, respectively.

[0065] A mother powder input line 520 is connected to the inlet of the chamber so that the mother powder having the polymer coating is input into the chamber. A mother powder supply device may be disposed on or connected to the mother powder input line 520, and in the embodiment shown in Figure 5, a feedstock hopper 525 is disposed on the mother powder input line 520.

[0066] A treated powder separation device 580 including a cyclone separator and an electrostatic precipitator is disposed in the discharge line 550 for the treated powder.

[0067] The gas supply device 560 supplies compressed gas to the mother powder input line 520 and the gas injector 530. The gas supply device 560 can supply compressed gas to the mother powder input line 520 and the gas injector 530 at different gas pressures.

[0068] The powder material processing device shown in FIG. 5 also has powder counters 570 arranged on the input line for the base powder and on the discharge line for the processed powder.

[0069] The powder processing device according to the present invention has the great advantage that it can be used for both batch and continuous processes because it can easily separate powders that have been carbonized from those that have not. In the continuous process, the IPL can be applied in repeated 5-10 millisecond IPL pulses at intervals of about 1 to 2 seconds.

[0070] In addition, the powder processing apparatus according to the present invention forms a closed loop system to prevent gas contamination and continuously reuse the gas. For example, as shown in Fig. 4, after separating fine powder in the exhaust gas using an electrostatic precipitator, the exhaust gas can be re-supplied to the compressed air supply device to form a closed loop system.

[0071] FIG. 6 is a schematic diagram of a powder material processing apparatus according to yet another embodiment of the present invention.

[0072] 6, the powder material processing device shown includes a chamber 610, a gas injector 630, an IPL irradiator 640, a reflector, etc. The mother powder supply device, the processing powder separation device, etc. may be the same as those illustrated in FIG. 4 or FIG. 5.

[0073] Unlike the embodiments shown in Figures 4 and 5, the embodiment shown in Figure 6 has an IPL irradiator 640 disposed on the side of the chamber. If the side of the chamber is made of a light-transmitting material (such as glass or transparent polycarbonate), as in the example shown in Figure 6, the IPL irradiator 640 may be disposed outside the chamber, and the IPL 645 may be transmitted through the side of the chamber and applied to the base powder 601 inside the chamber.

[0074] As described above, the present invention allows the application of IPL to carbonize the polymer coating of a powder material to a desired degree. In particular, the present invention uses air pressure and gravity to allow the polymer to escape to the outside without further carbonization when the carbonization rate of the polymer reaches a target value, thereby providing uniform carbonization of the powder.

[0075] Although the present invention has been described above with reference to the preferred embodiment, various modifications and variations within the skill of ordinary artisans can be made therein, and it is understood that these modifications and variations are included within the scope of the present invention as long as they do not deviate from the scope of the present invention.

Claims

1. a chamber; a mother powder feeding line through which the mother powder having a polymer coating is fed into the chamber; a gas injector disposed on the bottom surface of the chamber for injecting air upward to suspend the base powder within the chamber; an IPL (Intense Pulsed Light) irradiator for carbonizing the polymer coating of the base powder; a discharge line for the treated powder that discharges the treated powder with the carbonized polymer coating out of the chamber; Including, Powder material processing equipment.

2. the gas injector injects air upward at an air pressure corresponding to the gravity acting on the base powder so that the gravity acting on the base powder and the buoyancy force are balanced to suspend the base powder at a specific height within the chamber; a discharge line for the treated powder is formed at a position higher than the specific height so that the treated powder, which has become lighter than the base powder due to the carbonization, can be discharged outside the chamber by the gas injector; The powder material processing apparatus according to claim 1 .

3. The powder material processing device further includes a compressed air supply; the compressed air supply is in fluid communication with the base powder input line and the gas injector; The powder material processing device according to claim 1 or 2.

4. The powder material processing device further includes a powder number counter disposed on the input line of the base powder and the discharge line of the processed powder, respectively. The powder material processing device according to claim 1 or 2.

5. a feedstock hopper is disposed in the input line of the mother powder, or the input line of the mother powder is connected to a discharge line of a mother powder storage device or a powder drying device; The powder material processing device according to claim 1 or 2.

6. The IPL irradiator is disposed on the side or top surface of the chamber. The powder material processing device according to claim 1 or 2.

7. The powder material treatment device further includes a reflector covering all surfaces except the irradiation surface of the IPL irradiator. The powder material processing apparatus according to claim 6 .

8. The IPL irradiator has an air flow path through which air passes. The powder material processing device according to claim 1 or 2.

9. The discharge line for the treated powder is connected to or includes a cyclone separator so that the air and the treated powder are separated from each other. The powder material processing device according to claim 1 or 2.

10. adding the polymer-coated mother powder into a chamber through which air is injected upward to suspend the mother powder in the chamber; applying intense pulsed light (IPL) to the base powder to carbonize the polymer coating from its surface; discharging the treated powder from the chamber after the polymer coating has been carbonized; Including, Methods for processing powder materials.

11. injecting air upward at an air pressure corresponding to the gravity acting on the base powder so that the gravity acting on the base powder and the buoyancy force are balanced to suspend the base powder at a specific height within the chamber; The treated powder, which has become lighter than the base powder due to the carbonization, is discharged out of the chamber by the air pressure.

11. The method for processing powder material according to claim 10.

12. further comprising supplying compressed air from a compressed air supplier into the chamber to transport the base powder into the chamber and to spray air upward.

12. A method for processing a powder material according to claim 10 or claim 11.

13. further comprising monitoring the number of base powders supplied into the chamber and the number of treated powders discharged out of the chamber, 12. A method for processing a powder material according to claim 10 or claim 11.

14. and separating fine powder in the exhaust gas with an electrostatic precipitator, and then supplying the exhaust gas back to the compressed air supply machine to form a closed loop system.

13. The method for processing powder material according to claim 12.

Images