Apparatus and method for uniformly processing powder materials using IPL (Intense Pulsed Light).

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 manufacturing technology for powders such as anode / cathode powders for lithium secondary batteries.

[0002] More specifically, the present invention relates to an apparatus and method for treating powder materials using IPL( Intense Pulse Light ).

Background Art

[0003] Lithium secondary batteries such as lithium-ion batteries have a wide range of applications from small and portable electronic products to large electric vehicles, so their demand is increasing. The conversion from fossil fuel vehicles to electric vehicles is becoming visible, which has further increased the interest in high-performance lithium secondary batteries. Various studies have been conducted to achieve higher capacity, longer life, faster charging, and reliable safety of lithium secondary batteries. One of them is to develop anodes and cathodes with higher energy density than before.

[0004] Silicon (Si) having a theoretical capacity of 4,200 mAh / g has attracted attention as a candidate for an active material for an anode of a lithium-based battery due to its high energy density. Similarly, sulfur (S) having a theoretical capacity of 1,675 mAh / g has attracted attention as a candidate for an active material for a cathode of a lithium-based battery. However, silicon and sulfur are known to have a high volume expansion rate during repeated lithiation processes. These rapid volume changes lead to pulverization and peeling of the active material, resulting in loss of electrode integrity and electrical insulation, and degrading the performance of the battery.

[0005] To solve the problems related to the volume expansion rate of these active materials, a scheme for treating the surface of the active material has been proposed.

[0006] Korean Published Patent Publication No. 10-2014-0034879 (published March 20, 2014) discloses a method for surface-treating silicon particles with a polymer such as polyalkylene oxide. By coating silicon particles with a polymer, damage due to volume changes in the silicon particles during the charging and discharging process can be prevented.

[0007] However, simply coating silicon particles with polymers 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] Therefore, the inner portion of the polymer in the thickness direction needs to be maintained in a polymeric state, while the outer portion of the polymer in the thickness direction needs to harden.

[0009] One method for hardening the outer portion of a polymer in the thickness direction involves further coating the polymer-coated powder material with carbon or metal. However, this method is disadvantageous in terms of time and cost because it requires an additional coating process.

[0010] Another method for hardening the outer portion of a polymer in the thickness direction involves carbonizing only the outer portion of the polymer coating in the thickness direction. This method may not require a separate coating process. However, with traditional heating methods, it is difficult to carbonize only the outer portion of the polymer coating in the thickness direction. [Overview of the project] [Problems that the invention aims to solve]

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

[0012] To solve the aforementioned problems, the powder material processing apparatus according to the present invention includes a chamber, a mother powder input line into which a mother powder (raw powder) having a polymer coating is introduced into the chamber, a gas injector positioned at the bottom of the chamber and 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 processed powder discharge line for discharging the processed powder with the polymer coating carbonized to the outside of the chamber.

[0013] The gas injector injects air upward at an air pressure corresponding to the gravity acting on the mother powder so that the gravity and buoyancy acting on the mother powder balance each other and cause the mother powder to float at a specific height within the chamber, and the discharge line for the processed powder may be formed at a position higher than the specific height so that the processed powder, which has become lighter than the mother powder due to carbonization, is discharged out of the chamber by the gas injector.

[0014] The processing apparatus for the powder material further includes a compressed air supply, which can be in fluid communication with the input line for the master powder and the gas injector.

[0015] The processing apparatus for the powder material may further include powder counters positioned in the input line for the master powder and the discharge line for the processed powder, respectively.

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

[0017] The IPL irradiator may be positioned on the side or top surface of the chamber. In this case, the processing apparatus for the powder material may further include a reflector that covers all surfaces except the irradiation surface of the IPL irradiator.

[0018] The IPL irradiator may be equipped with an air channel through which air passes.

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

[0020] To solve the aforementioned problems, the present invention provides a method for processing powdered materials, comprising the steps of: introducing a mother powder having a polymer coating into a chamber from which air is injected upward, thereby causing the mother powder to suspend within the chamber; applying IPL to the mother powder to carbonize the polymer coating from its surface; and discharging the processed powder, from which the polymer coating has been carbonized, from the chamber.

[0021] In this configuration, air may be injected upward with an air pressure corresponding to the gravity acting on the mother powder to balance the gravitational force and buoyancy acting on the mother powder, causing the mother powder to float at a specific height within the chamber. The processed powder, which has become lighter than the mother powder due to carbonization, may then be discharged from the chamber by the air pressure.

[0022] In one embodiment of the present method, the method further includes supplying compressed air from a compressed air supply to the interior of the chamber in order to transfer the mother powder into the chamber and to inject air upward.

[0023] In one embodiment of the present method, the method further includes monitoring the number of master powders supplied into the chamber and the number of processed powders discharged outside the chamber.

[0024] In one embodiment of this method, the method further includes separating fine powder from the exhaust gas with an electrostatic precipitator, and then supplying the exhaust gas back to the compressed air supply to form a closed-loop system. [Effects of the Invention]

[0025] In the present invention, by applying IPL with a pulse duration of several milliseconds and applying energy only up to a limited depth from the surface of the polymer, only the outer portion in the thickness direction of the polymer coating in the powder material of the polymer coating can be carbonized.

[0026] Particularly, in the present invention, when the carbonization ratio of the polymer reaches the target value by using air pressure and gravity, the polymer can be prevented from carbonizing further and escaping to the outside, thereby providing uniform carbonization. Also, these processes can be performed in a continuous process.

Brief Description of the Drawings

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

[0028] [Figure 1] It is a diagram schematically showing examples of the powder material before and after carbonization. [Figure 2] It is a diagram schematically showing a method for treating a powder material according to the present invention. [Figure 3] It is a diagram schematically showing the magnitudes of the air pressure and gravity respectively received by the mother powder before and after carbonization. [Figure 4] It is a diagram schematically showing a processing apparatus for a powder material according to an embodiment of the present invention. [Figure 5] It is a diagram schematically showing a processing apparatus for a powder material according to another embodiment of the present invention. [Figure 6] It is a diagram schematically showing a processing apparatus for a powder material according to still another embodiment of the present invention.

Modes for Carrying Out the Invention

[0029] The following description and the embodiments described herein are provided as examples of the principles of various forms of the present invention. These embodiments are not intended to limit the present invention in these principles or in various forms, but are provided for illustrative purposes only. Throughout the description of the specification and drawings, similar parts are denoted by the same reference numerals. The drawings are not necessarily to scale, and in some cases, the proportions may be exaggerated to more clearly depict certain features.

[0030] Figure 1 is a schematic diagram showing examples of powder materials before and after carbonization.

[0031] Figure 1 illustrates 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 both the mother powder 100 before carbonization and the processed powder 200 after carbonization.

[0032] Referring to Figure 1, the mother powder 100 includes a core active material 110 and a polymer coating 120 on the surface of the core active material 110. Optionally, a carbon-based additive 130 may be dispersed in the polymer coating 120.

[0033] The mother powder 100 having a polymer coating is IPL ( Intense Pulse Light By applying IPL, part or all of the surface of the polymer coating 120 is carbonized, and processed powder 200 is generated. In Figure 1, the processed powder 200 generated by the application of IPL, which partially carbonizes the surface of the polymer coating, includes an outer shell 121 and an inner shell 122, and nanopores 125 are formed in the outer shell. The outer shell 121 is hard and may be carbonized, while the inner shell 122 is soft and may not be carbonized.

[0034] In the processed powder 200 of Figure 1, the outer shell 121 provides structural support and electrical conductivity to form a thin and stable solid electrolyte interface. The inner shell 122 is filled with a relatively soft polymer that is not carbonized, reducing mechanical stress on the volume change of the active material during the lithiation and delithiation processes. Multiple nanopores 125 allow lithium ions to diffuse easily.

[0035] Figure 2 is a schematic diagram illustrating the processing method for powder materials according to the present invention.

[0036] Referring to Figure 2, the method for processing powder materials according to the present invention includes a mother powder input step (S210), a polymer coating and carbonization step using IPL (S220), and a processed powder discharge step (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, causing the mother powder having the polymer coating to float within the chamber. The mother powder having the polymer coating may be powder-dried, but is not necessarily limited to this. In other examples, the mother powder may be in the form of droplets containing a solvent, in which case the chamber to which the IPL is applied is further equipped with a heating means such as a heater, so that both drying of the mother powder and carbonization of the polymer coating can be performed. In other examples, the droplet-shaped mother powder 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 into the chamber by a compressed air supply to transfer the mother powder 100 into the chamber and to inject air upwards.

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

[0040] In the polymer coating carbonization step using IPL (S220), IPL is applied to the base powder 100 having a polymer coating to produce a treated powder 200 in which the polymer coating is carbonized from its surface. 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, allowing the polymer coating to be partially carbonized. Of course, the pulse duration, pulse type, and number of applications of the IPL can be controlled so that the entire polymer coating is carbonized.

[0041] IPL (Intense Pulsed Light) uses fast-emitting photoelectron waves generated by a xenon lamp. When a high-intensity electrical pulse is applied by a xenon gas-charged lamp, photon irradiation occurs when the xenon gas is excited to a higher energy state and then falls back to a lower state. The energy emitted in the form of intense pulsed light is also called a flash. IPL technology has advantages over other electromagnetic energy application processes such as lasers and microwaves because it can cover a large surface area in a short time. IPL generally has a wide pulsed light spectrum in the 200-1100 nm range. Modern IPL devices use computer-controlled capacitor banks to generate IPL where pulse duration, pulse interval, pulse number, and intensity are manipulated. Fluance (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] Applying IPL is preferable to powder treatment because the IPL can irradiate a large surface area at once.

[0043] In the processed powder discharge stage (S230), the processed powder 200, in which part or all of the polymer coating has been carbonized, is discharged to the outside of the chamber. The number of processed powders 200 discharged to the outside of the chamber, as well as the number of master powders supplied into the chamber, can be monitored using a powder counter.

[0044] Figure 3 is a schematic diagram showing the magnitudes of air pressure and gravity acting on the mother powder before and after carbonization.

[0045] As shown in the example in Figure 3(a), when the gravitational force acting on the mother powder and the buoyant force due to air pressure are balanced, the mother powder is maintained in a floating state at a specific height within the chamber while rotating. In other words, the mother powder with a polymer coating rotates in the air within the chamber due to air pressure, repeatedly rising and falling slightly, and is maintained at a specific height.

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

[0047] In this invention, by applying IPL, only the outer portion of the polymer coating in the thickness direction of the polymer coating powder material can be carbonized. In particular, in this invention, when the carbonization rate of the polymer reaches a target value using air pressure and gravity, the polymer is allowed to escape to the outside without further carbonization, thereby providing uniform carbonization.

[0048] If the air pressure is too high, the degree of carbonization of the powder may vary slightly due to differences in the spacing between powder particles and the IPL application distance. However, in this invention, by using a balance between air pressure and gravity, when the carbonization rate of the polymer reaches a target value, the polymer is prevented from carbonizing any further, thereby achieving uniform carbonization of the polymer coating on the powder. For this reason, in this invention, sufficient air pressure is applied so that the powder floats at a specific height.

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

[0050] Referring to Figure 4, the processing apparatus for powder materials according to the present invention includes a mother powder supply device 410, a chamber 420, a gas injector 430, an IPL irradiator 440, and processing powder separation devices 450, 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 mother powder having a polymer coating is supplied into the chamber. The mother powder supply device 410 may be in the form of a storage tank, a feedstock hopper, or a powder dryer.

[0052] Chamber 420 is a space in which the mother powder is processed by applying energy, and the inner surface of the chamber may consist of reflective surfaces that reflect light, except for the inlet 422, outlet 424, and IPL irradiator 440.

[0053] The gas injector 430 is positioned at the bottom of the chamber and connected to a 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, which supplies mother powder for transfer. The gas injector 430 injects compressed gas upward inside the chamber, causing the mother powder to suspend within the chamber. The gas can be air, argon, nitrogen, or the like.

[0054] The gas injector 430 can balance the gravitational and buoyant forces acting on the mother powder, causing it to levitate at a specific height within the chamber. To balance the gravitational and buoyant forces acting on the mother powder, the gas injector can inject gas upward at an air pressure corresponding to the gravitational force acting on the mother powder.

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

[0056] Figure 4 shows an example where the IPL irradiator 440 is positioned at the top of the chamber 420 and IPL is applied from top to bottom; however, the system is not limited to this, and the IPL irradiator may be positioned on the side or bottom of the chamber. To improve the efficiency of IPL application, the inner surface of the chamber may be composed of reflective surfaces.

[0057] Furthermore, the temperature of the IPL irradiator 440 may rise due to the application of IPL, and for cooling purposes, an air passage may be provided in the IPL irradiator. Compressed air introduced into the chamber through the air passage can cool the IPL irradiator as it passes through the air passage inside the IPL irradiator.

[0058] The outlet 424 is formed through the chamber 420 to discharge the carbonized processed powder with the polymer coating. The outlet 424 may be formed above a certain floating height so that the processed powder, which has become lighter than the mother powder due to carbonization, is discharged by the air pressure provided by the gas injector 430.

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

[0060] On the other hand, the processing apparatus for powder materials may further include a compressed gas supply unit, i.e., a compressor 407, and 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 the chamber inlet 422 via a mother powder feeding line. The low-pressure regulator 408-1 and the high-pressure regulator 408-2 may supply compressed gas into the chamber 420 at different gas pressures via the inlet 422 and the gas injector 430.

[0061] In Figure 4, reference numeral 401 denotes a ball valve, reference numeral 402 denotes a ball valve in its mainly 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 or powder, and for connecting each element, etc.

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

[0063] Referring to Figure 5, the powder material processing apparatus according to this embodiment includes a chamber 510, a mother powder input line 520 into which mother powder is introduced 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] In the powder material processing apparatus shown in Figure 5, the chamber 510, gas injector 530, and IPL irradiator 540 can be substantially the same as those shown in Figure 4, specifically the chamber 420, gas injector 430, and IPL irradiator 440.

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

[0066] A processing powder separation device 580, which includes a cyclone separator and an electrostatic precipitator, is positioned in the processing powder discharge line 550.

[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] Furthermore, the powder material processing apparatus shown in Figure 5 is equipped with powder counters 570 located in the input line for the master powder and the discharge line for the processed powder, respectively.

[0069] A major advantage of the powder processing apparatus according to the present invention is that it can easily separate powders that have completed carbonization from those that have not, enabling not only batch processes but also continuous processes. During continuous processes, the IPL may be applied by repeatedly applying 5-10 millisecond IPL pulses at intervals of approximately 1 to 2 seconds.

[0070] Furthermore, the powder processing apparatus according to the present invention forms a closed-loop system to prevent gas contamination and allows for continuous reuse of the gas. For example, as shown in the example in Figure 4, a closed-loop system can be formed by separating the fine powder in the exhaust gas with an electrostatic precipitator and then supplying the exhaust gas back to the compressed air supply.

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

[0072] Referring to Figure 6, the powder material processing apparatus shown includes a chamber 610, a gas injector 630, an IPL irradiator 640, a reflector, and the like. The mother powder supply device, the processed powder separation device, and the like can be the same as those exemplified in Figure 4 or Figure 5.

[0073] Unlike the embodiments shown in Figures 4 and 5, in the embodiment shown in Figure 6, the IPL irradiator 640 is positioned on the side of the chamber. If the side of the chamber is formed from a translucent material (such as glass or transparent polycarbonate), the IPL irradiator 640 may be positioned outside the chamber, as in the example shown in Figure 6, so that the IPL 645 passes through the side of the chamber and is applied to the mother powder 601 inside the chamber.

[0074] As described above, in the present invention, it is possible to carbonize the polymer coating in the polymer coating powder material to a desired degree by applying IPL. In particular, in the present invention, when the carbonization rate of the polymer reaches a target value using air pressure and gravity, the polymer is allowed to escape to the outside without further carbonization, thereby providing uniform carbonization to the powder.

[0075] The above description has focused on embodiments of the present invention, but various modifications and variations can be made at the level of an ordinary engineer. Therefore, these modifications and variations can be understood to fall within the scope of the present invention, as long as they do not deviate from the scope of the present invention.

Claims

1. Chamber and, A mother powder input line in which a mother powder having a polymer coating is introduced into the chamber, A gas injector is positioned at the bottom of the chamber and sprays air upward to suspend the mother powder within the chamber. The system includes an IPL (intense pulsed light) irradiator for carbonizing the polymer coating of the mother powder, and a processed powder discharge line for discharging the processed powder, in which the polymer coating has been carbonized, to the outside of the chamber. The gas injector injects air upward at an air pressure corresponding to the gravity acting on the mother powder, so as to balance the gravitational force and buoyancy acting on the mother powder and cause the mother powder to float at a specific height within the chamber. The discharge line for the processed powder is formed at a position higher than the specified height so that the processed powder, which has become lighter than the mother powder due to carbonization, is discharged outside the chamber by the gas injector. Processing equipment for powder materials.

2. The aforementioned processing apparatus for powder materials further includes a compressed air supply, The compressed air supply unit is in fluid communication with the mother powder input line and the gas injector. The apparatus for processing powder materials according to claim 1.

3. The processing apparatus for the powder material further includes powder counters positioned in the input line for the master powder and the discharge line for the processed powder, respectively. A processing apparatus for powder materials according to claim 1 or claim 2.

4. A feedstock hopper is placed in the mother powder input line, or the mother powder input line is connected to the discharge line of a mother powder storage device or powder drying device. A processing apparatus for powder materials according to claim 1 or claim 2.

5. The IPL irradiator is located on the side or top surface of the chamber. A processing apparatus for powder materials according to claim 1 or claim 2.

6. The processing apparatus for the powder material further includes a reflector that covers all surfaces except the irradiation surface of the IPL irradiator. The apparatus for processing powder materials according to claim 5.

7. The IPL irradiator is equipped with an air passage through which air passes. A processing apparatus for powder materials according to claim 1 or claim 2.

8. The discharge line for the processed powder is connected to or includes a cyclone separator so that the air and the processed powder are separated. A processing apparatus for powder materials according to claim 1 or claim 2.

9. The process involves introducing a mother powder having a polymer coating into a chamber from which air is injected upward, and injecting air upward at an air pressure corresponding to the gravity acting on the mother powder so that the gravity acting on the mother powder balances the buoyancy and causes the mother powder to float at a specific height within the chamber; The steps include: irradiating the mother powder with IPL (intense pulsed light) to carbonize the polymer coating from its surface; The process involves discharging the processed powder, which has become lighter than the mother powder due to the carbonization, out of the chamber by air pressure. including, A method for processing powdered materials.

10. The further includes supplying compressed air from a compressed air supply to the interior of the chamber in order to transfer the mother powder into the chamber and to inject air upward, The method for processing powdered material according to claim 9.

11. The further includes monitoring the number of master powders supplied into the chamber and the number of processed powders discharged outside the chamber, respectively. A method for processing powdered material according to claim 9 or claim 10.

12. The system further includes separating fine powder from the exhaust gas using an electrostatic precipitator, and then supplying the exhaust gas back to the compressed air supply to form a closed-loop system. A method for processing powdered material according to claim 10.

Images