Device and method for uniformly treating powder material by using intense pulsed light

Abstract

The invention discloses a device and a method for treating a powder material by utilizing intense pulsed light (IPL). The powder processing apparatus according to the present invention comprises: a chamber; a mother powder feeding line for feeding mother powder having a polymer coating layer into the inside of the chamber; the gas ejector is arranged on the bottom surface of the chamber and ejects air upwards to enable the mother powder to suspend in the chamber; an intense pulsed light irradiator for carbonizing the polymer coating layer of the mother powder; and a treated powder discharge line for discharging the carbonized treated powder of the polymer coating.

Description

Technical Field

[0001] The present invention relates to a technology for producing anode / cathode powder and the like for lithium secondary batteries.

[0002] More specifically, the present invention relates to an apparatus and method for treating powder materials using intense pulsed light (IPL). Background Art

[0003] Lithium secondary batteries, such as lithium-ion batteries, are used in a wide range of applications, from small, portable electronic products to large electric vehicles, and their demand is increasing. As the shift from fossil fuel vehicles to electric vehicles becomes more widespread, the focus on high-performance lithium secondary batteries is also increasing. In order to achieve higher capacity, longer life, faster charging speed and more reliable safety of lithium secondary batteries, many studies are being conducted, one of which is to develop and apply negative and positive electrodes with higher energy density than existing materials.

[0004] Silicon (Si) is considered a strong candidate for the negative electrode active material of lithium batteries due to its theoretical capacity of up to 4200mAh / g and high energy density. Similarly, sulfur (S) is also considered a strong candidate for the positive electrode active material of lithium batteries due to its theoretical capacity of 1675mAh / g. However, it is widely known that silicon and sulfur have a high volume expansion rate during repeated lithiation processes. This drastic volume change can lead to the pulverization and peeling of the active material, resulting in a loss of electrode integrity and electrical insulation, which reduces the performance of the battery.

[0005] In order to solve the problem related to the volume expansion rate of such active materials, it has been proposed to treat the surface of the active materials.

[0006] Korean Patent Publication No. 10-2014-0034879 (published on March 20, 2014) discloses a method of treating the surface of a plurality of silicon particles with a polymer such as polyalkane oxide. By coating a plurality of silicon particles with a polymer, it is possible to prevent the silicon particles from being damaged due to volume changes during charge and discharge.

[0007] However, simply coating the plurality of silicon particles with a polymer does not provide structural strength, and therefore, it is difficult to effectively suppress the volume expansion of the plurality of silicon particles.

[0008] For this purpose, the inner portion of the polymer in the thickness direction needs to be kept in the polymer state, and the outer portion of the polymer in the thickness direction needs to be made strong.

[0009] As a method of strengthening the outer portion of the polymer in the thickness direction, a method of additionally coating the powder material with the polymer coating with carbon or metal can be considered. However, this method requires adding a separate coating process, which is disadvantageous in terms of time and economy.

[0010] As another method for making the outer portion of the polymer in the thickness direction hard, a method of carbonizing only the outer portion of the polymer coating in the thickness direction can be considered. This method may not require a separate coating process. However, it is difficult to carbonize only the outer portion of the polymer coating in the thickness direction by a conventional heating method. Summary of the invention Technical issues

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

[0012] The powder material processing device of the present invention for solving the above-mentioned problem comprises: a chamber; a mother powder input line for inputting mother powder having a polymer coating into the interior of the chamber; a gas injector, which is arranged on the bottom surface of the chamber and suspends the mother powder in the chamber by ejecting air upward; an intense pulse light irradiator for carbonizing the polymer coating of the mother powder; and a processed powder discharge line for discharging the processed powder whose polymer coating has been carbonized.

[0013] The gas injector can spray air upward at an air pressure corresponding to the gravity exerted on the mother powder, so that the gravity exerted on the mother powder is balanced with the suspension force, thereby causing the mother powder to be suspended at a specific height in the chamber. The processed powder discharge line can be formed at a position higher than the specific height, so that the processed powder that becomes lighter than the mother powder through the carbonization can be discharged with the help of the gas injector.

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

[0015] The powder material processing device may further include powder quantity counters respectively arranged on the mother powder input line and the processed powder discharge line.

[0016] The mother powder input line may be provided with a feeding hopper, or the mother powder input line may be connected to a mother powder storage device or a discharge line of a powder drying device.

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

[0018] The intense pulsed light irradiator may be provided with an air channel to allow air to pass through.

[0019] The treated powder discharge line may be connected to or include a cyclone separator to separate the treated powder from the air.

[0020] The powder material processing method of the present invention for solving the above-mentioned problem comprises the following steps: putting a mother powder having a polymer coating into a chamber that sprays air upward, so that the mother powder is suspended in the chamber; applying strong pulse light to the mother powder, so that the polymer coating begins to carbonize from its surface; and discharging the processed powder whose polymer coating has been carbonized.

[0021] By spraying air upward at an air pressure corresponding to the gravity exerted on the mother powder, the gravity exerted on the mother powder can be balanced with the suspension force, so that the mother powder is suspended at a specific height in the chamber, and the processed powder that becomes lighter than the mother powder through carbonization can be discharged with the help of the air pressure.

[0022] Compressed air may be supplied from a compressed air supplier to the inside of the chamber to move the mother powder into the inside of the chamber and spray the air upward.

[0023] The amount of mother powder supplied to the inside of the chamber and the amount of processed powder discharged to the outside of the chamber may be monitored.

[0024] After fine dust is separated from the exhausted gas by an electric precipitator, the exhausted gas is supplied to the compressed air supplier again, thereby forming a closed loop system. Effects of the Invention

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

[0026] In particular, in the present invention, when the carbonization ratio of the polymer reaches the target value, the gas pressure and gravity can be used to stop the polymer from further carbonization and make it flow out to the outside, thereby achieving uniform carbonization. Moreover, this process can be performed through a continuous process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] With reference to the accompanying drawings, several embodiments of the present invention are shown in detail by way of example and not by way of limitation.

[0028] Figure 1 An example of a powder material before and after carbonization is briefly shown.

[0029] Figure 2 The powder material processing method of the present invention is briefly shown.

[0030] Figure 3 The figure briefly shows the air pressure and gravity on the mother powder before and after carbonization.

[0031] Figure 4 A powder material processing device according to an embodiment of the present invention is briefly shown.

[0032] Figure 5 A powder material processing device according to another embodiment of the present invention is briefly shown.

[0033] Figure 6 A powder material processing apparatus according to another embodiment of the present invention is briefly shown. DETAILED DESCRIPTION

[0034] The following description and the embodiments described herein are provided as examples of the principles of various embodiments of the present invention. These embodiments are only used to illustrate these principles and various embodiments, and are not intended to limit the present invention. Throughout the specification and drawings, similar parts are given the same reference numerals. The drawings are not necessarily drawn to scale, and in some cases, the proportions may be exaggerated in order to more clearly describe specific features.

[0035] Figure 1 An example of a powder material before and after carbonization is briefly shown.

[0036] exist Figure 1 , silicon powder that can be used as a negative electrode for lithium secondary batteries such as lithium ion batteries, lithium metal batteries, lithium sulfur batteries, and lithium air batteries is shown, and mother powder 100 before carbonization and processed powder 200 after carbonization are shown.

[0037] Reference 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. A carbon additive 130 may be dispersed in the polymer coating 120 as required.

[0038] The mother powder 100 with the polymer coating is partially or completely carbonized starting from the surface of the polymer coating 120 by applying strong pulse light, thereby generating the processed powder 200. Figure 1In the embodiment, the polymer coating is partially carbonized by applying strong pulse light, and the generated treated powder 200 includes an outer shell 121 and an inner shell 122, and is formed with nano-pores 125. The outer shell 121 is hard and carbonized, and the inner shell 122 is soft and may not be carbonized.

[0039] exist Figure 1 In the treated powder 200, the outer shell 121 provides structural support and conductivity, thereby forming a thin and stable solid electrolyte interface. The inner shell 122 is filled with relatively soft polymers that are not carbonized, which can reduce the mechanical stress caused by the volume change of the active material during the lithiation and delithiation process. The multiple nanopores 125 facilitate the diffusion of lithium ions.

[0040] Figure 2 The powder material processing method of the present invention is briefly shown.

[0041] Reference Figure 2 The powder material processing method of the present invention includes a mother powder input step S210, a polymer coating carbonization step S220 using intense pulse light, and a processed powder discharge step S230.

[0042] In the mother powder feeding step S210, the mother powder 100 with a polymer coating is fed into the chamber. Air is sprayed upward inside the chamber, whereby the mother powder with a polymer coating is suspended in the chamber. The mother powder with a polymer coating may be a dry powder, but is not limited thereto. In another example, the mother powder may also be in the form of droplets containing a solvent. In this case, the chamber to which the strong pulse light is applied is additionally provided with a heating device such as a heater, so that the mother powder can be dried and the polymer coating can be carbonized simultaneously. In another example, after the mother powder in the form of droplets is dried in a drying chamber, the dried mother powder can be fed into the chamber to which the strong pulse light is applied.

[0043] Compressed air may be supplied from a compressed air supplier to the inside of the chamber to move the mother powder 100 to the inside of the chamber and spray the air upward.

[0044] The amount of mother powder 100 supplied into the chamber may be monitored using a powder amount counter.

[0045] In the polymer coating carbonization step S220 using intense pulsed light, the mother powder 100 with the polymer coating is subjected to intense pulsed light, thereby generating 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 according to the application conditions of the intense pulsed light. The pulse duration of the intense pulsed light is several milliseconds, and the energy can be applied only to a limited depth from the surface of the polymer coating, so that the polymer coating is partially carbonized. Of course, the pulse duration, pulse shape, application times, etc. of the intense pulsed light can be controlled so that the polymer coating is completely carbonized.

[0046] IPL uses a rapid burst of electromagnetic light produced by a xenon lamp. When a high-intensity electrical pulse is applied through a xenon-filled lamp, the xenon is excited to a higher energy state and then drops back to a lower state, producing photon radiation. The energy radiated 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 covers a wider surface area in a short period of time. In addition, IPL typically has a broad spectrum of pulses ranging from 200nm to 1100nm. The latest IPL devices use computer-controlled capacitor banks to generate IPL with adjustable pulse duration, pulse interval, number of pulses, and intensity. The irradiated energy density (radiant energy per unit area of ​​surface) 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.

[0047] Since IPL can irradiate a larger surface area at one time, IPL application is more suitable for powder processing.

[0048] In the treated powder discharging step S230, the treated powder 200 with the polymer coating partially or completely carbonized is discharged to the outside of the chamber. Like the amount of mother powder supplied to the inside of the chamber, the amount of treated powder 200 discharged to the outside of the chamber can be monitored by a powder amount counter.

[0049] Figure 3 The figure briefly shows the air pressure and gravity on the mother powder before and after carbonization.

[0050] like Figure 3 In the example shown in part (a), when the gravity on the mother powder and the suspension force due to the air pressure are balanced, the mother powder rotates to maintain a suspended state at a specific height in the chamber. That is, the mother powder with a polymer coating rotates in the air due to the air pressure inside the chamber and repeatedly rises and falls slightly to maintain a specific height.

[0051] When the polymer coating is carbonized, multiple components other than carbon in the polymer coating are removed from the polymer coating, so that the weight of the powder is reduced. As a result, the processed powder whose polymer coating is carbonized will be subjected to a gas pressure greater than gravity, and eventually, the processed powder can be discharged to the outside of the chamber due to the gas pressure.

[0052] In the present invention, only the outer portion of the polymer coating in the thickness direction of the polymer coating in the polymer coating powder material can be carbonized by applying strong pulse light. In particular, in the present invention, when the carbonization ratio of the polymer reaches the target value, the polymer is no longer carbonized and flows out to the outside, thereby achieving uniform carbonization.

[0053] If the air pressure is too high, the degree of carbonization of the powder may be slightly different due to differences in the shadows between the powders and the distance of the intense pulsed light application. However, in the present invention, the balance of air pressure and gravity is utilized, and when the carbonization ratio of the polymer reaches the target value, the polymer is no longer carbonized, thereby achieving uniform carbonization of the polymer coating of the powder. For this reason, in the present invention, the air pressure is only applied to a degree that allows the powder to barely suspend at a specific height.

[0054] Figure 4 A powder material processing device according to an embodiment of the present invention is briefly shown.

[0055] Reference Figure 4 The powder material processing device of the present invention includes a mother powder supply device 410, a chamber 420, a gas injector 430, an intense pulse light irradiator 440, and processed powder separation devices 450 and 470.

[0056] The mother powder supply device 410 is connected to the inlet 422 of the chamber 420 through a mother powder input line to supply the mother powder with a polymer coating into the chamber. The mother powder supply device 410 can be in the form of a storage tank, a feedstock hopper, or a powder drying device.

[0057] The chamber 420 is a space for processing mother powder by applying energy, and the inner surface of the chamber except for the inlet 422, the outlet 424, and the intense pulse light irradiator 440 can be composed of a reflective surface that reflects light.

[0058] The gas injector 430 is disposed on the bottom surface of the chamber. It is connected to the gas supply device 406. The gas supply device 406 connected to the gas injector 430 can also be connected to the powder supply device 410 for supplying the mother powder, etc., to transfer the mother powder. The gas injector 430 injects compressed gas upward inside the chamber to suspend the mother powder in the chamber. The gas may include air, argon, nitrogen, etc.

[0059] The gas injector 430 can balance the gravity and suspension force of the mother powder, so that the mother powder is suspended at a specific height in the chamber. The gas injector can inject gas upward at a pressure corresponding to the gravity of the mother powder, so as to balance the gravity and suspension force of the mother powder.

[0060] The intense pulse light irradiator 440 is used to carbonize the polymer coating of the mother powder. A xenon lamp can be used as the intense pulse light irradiator 440. The intense pulse light irradiator 440 is electrically connected to an alternating current (AC) power supply 442, and an intense pulse light power supply controller 444 can be provided between the intense pulse light irradiator 440 and the alternating current (AC) power supply 442.

[0061] Although in Figure 44 shows an example in which the IPL irradiator 440 is disposed at the upper part of the chamber 420 to apply IPL from the upper part to the lower part, but the present invention is not limited thereto, and the IPL irradiator can also be disposed at the side or bottom of the chamber. In order to improve the efficiency of applying IPL, the inner surface of the chamber can be formed by a reflective surface.

[0062] Furthermore, the temperature of the IPL irradiator 440 may increase with the application of IPL, and an air channel may be provided in the IPL irradiator for cooling so that air can pass through. Compressed air injected into the chamber through the air channel may pass through the air channel inside the IPL irradiator to cool the IPL irradiator.

[0063] The outlet 424 penetrates the chamber 420 so that the treated powder whose polymer coating has been carbonized can be discharged. The outlet 424 can be formed at a position higher than a specific suspension height so that the treated powder, which becomes lighter than the mother powder by carbonization, can be discharged by the gas pressure provided by the gas injector 430.

[0064] The processed powder separation devices 450 and 470 are used to separate gas and processed powder. The processed powder separation device may be connected to the cyclone separator 450, or include the cyclone separator 450. In addition, the processed powder separation device may include an electrostatic precipitator 470 (Electrostatic Precipitator) for separating fine dust that cannot be separated in the cyclone separator 450. The processed powder separated from the processed powder separation device may be stored in the powder storage device 460. The separated gas may be resupplied to the gas supply line of the gas supply device 406.

[0065] On the other hand, the powder material processing device may further include a compressed gas supplier, that is, a 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. With the help of the low pressure regulator 408-1 and the high pressure regulator 408-2, compressed gas may be provided to the interior of the chamber 420 via the inlet 422 and the gas injector 430 at different gas pressures.

[0066] exist Figure 4 , reference numeral 401 refers to a ball valve, reference numeral 402 refers to a ball valve that is mainly in a closed state, reference numeral 403 refers to a one-way check valve, reference numeral 404 refers to a threaded union, reference numeral 405 refers to a quick disconnect bleed port, and reference numeral 409 refers to a flow control valve. These elements are used to control the flow of gas or powder and connect multiple elements.

[0067] Figure 5 A powder material processing device according to another embodiment of the present invention is briefly shown.

[0068] Reference Figure 5 The powder material processing device of this embodiment includes: a chamber 510; a mother powder input line 520, which inputs the mother powder into the interior of the chamber; a gas injector 530, which injects gas into the interior of the chamber; an intense pulse light irradiator 540, which irradiates the interior of the chamber with intense pulse light 545; a processed powder discharge line 550, which discharges the processed powder from the chamber; and a gas supply device 560, which supplies compressed gas to the mother powder input line and the gas injector.

[0069] exist Figure 5 In the powder material processing device shown in FIG. 1 , the chamber 510, the gas injector 530, and the intense pulse light irradiator 540 can actually be connected with the Figure 4 The chamber 420, gas injector 430, and intense pulsed light irradiator 440 shown are the same.

[0070] The mother powder input line 520 is connected to the inlet of the chamber to input the mother powder with the polymer coating into the interior of the chamber. A mother powder supply device can be set or connected to the mother powder input line 520. Figure 5 In the illustrated embodiment, a feedstock hopper 525 is provided at the mother powder input line 520 .

[0071] The processed powder discharge line 550 is provided with a processed powder separation device 580 such as a cyclone separator and an electric precipitator.

[0072] 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.

[0073] And, in Figure 5 The powder material processing device shown is provided with a powder quantity counter 570, and the powder quantity counter 570 is respectively arranged on the mother powder input line and the processed powder discharge line.

[0074] Since the powder processing device of the present invention can easily separate the powder that has been carbonized and the powder that has not been carbonized, it can not only perform a batch process but also a continuous process, which is a major advantage. In the continuous process, the intense pulsed light can repeatedly apply 5 milliseconds to 10 milliseconds of intense pulsed light pulses at intervals of about 1 second to 2 seconds.

[0075] Furthermore, the powder processing device of the present invention can form a closed-loop system to prevent gas pollution and continuously recycle gas. Figure 4In the example shown, after fine dust is separated from the exhaust gas by the electric precipitator, the exhaust gas is resupplied to the compressed air supplier, thereby forming a closed loop system.

[0076] Figure 6 A powder material processing apparatus according to another embodiment of the present invention is briefly shown.

[0077] Reference Figure 6 The powder material processing device shown includes a chamber 610, a gas injector 630, an intense pulse light irradiator 640, a reflector, etc. The mother powder supply device, the processed powder separation device, etc. can be directly used Figure 4 or Figure 5 The device shown in .

[0078] and Figure 4 and Figure 5 The embodiment shown is different. Figure 6 In the embodiment shown, the IPL irradiator 640 is disposed on the side of the chamber. When the side of the chamber is formed of a light-transmitting material (glass or transparent polycarbonate, etc.), Figure 6 As shown, the intense pulsed light irradiator 640 can be disposed outside the chamber, and the intense pulsed light 645 can be applied to the mother powder 601 inside the chamber through the side of the chamber.

[0079] As shown above, in the present invention, the desired degree of carbonization of the polymer coating can be achieved in the polymer coating powder material by applying strong pulsed light. In particular, in the present invention, air pressure and gravity can be used to make the polymer no longer carbonized and flow out to the outside when the carbonization ratio of the polymer reaches the target value, thereby achieving uniform carbonization of the powder.

[0080] The above description is centered on the embodiments of the present invention, but a person skilled in the art may make various modifications or variations. Therefore, as long as such modifications and variations do not depart from the scope of the present invention, it can be understood that these modifications and variations are included in the scope of the present invention.

Claims

1. A powder material processing device, characterized in that: include: Chamber; A mother powder feeding line is used to feed the mother powder with a polymer coating into the interior of the chamber; A gas injector is disposed on the bottom surface of the chamber and allows the mother powder to be suspended in the chamber by injecting air upward; An intense pulsed light irradiator is used to carbonize the polymer coating of the mother powder; as well as The processed powder discharge line discharges the processed powder whose polymer coating has been carbonized.

2. The powder material processing device according to claim 1, characterized in that: The gas injector sprays air upward at an air pressure corresponding to the gravity of the mother powder, so that the gravity of the mother powder is balanced with the suspension force, so that the mother powder is suspended at a specific height in the chamber. The treated powder discharge line is formed at a position higher than the specific height so that the treated powder, which becomes lighter than mother powder by the carbonization, is discharged by means of the gas ejector.

3. The powder material processing device according to claim 1 or 2, characterized in that: The powder material processing device further comprises a compressed air supplier, The compressed air supplier is in fluid communication with the mother powder input line and the gas injector.

4. The powder material processing device according to claim 1 or 2, characterized in that: The powder material processing device further includes powder quantity counters respectively arranged on the mother powder input line and the processed powder discharge line.

5. The powder material processing device according to claim 1 or 2, characterized in that: The mother powder input line is provided with a feeding hopper, or the mother powder input line is connected to a mother powder storage device or a discharge line of a powder drying device.

6. The powder material processing device according to claim 1 or 2, characterized in that: The intense pulse light irradiator is arranged on the side surface or the upper surface of the chamber.

7. The powder material processing device according to claim 6, characterized in that: The powder material processing device further comprises a reflection plate, which covers all surfaces except the irradiation surface of the intense pulse light irradiator.

8. The powder material processing device according to claim 1 or 2, characterized in that: The intense pulse light irradiator is provided with an air channel for air to pass through.

9. The powder material processing device according to claim 1 or 2, characterized in that: The treated powder discharge line is connected to a cyclone separator or includes a cyclone separator to separate the treated powder from the air.

10. A method for processing powder material, characterized in that: The steps include: Putting the mother powder with the polymer coating into a chamber where air is sprayed upward, so that the mother powder is suspended in the chamber; Applying strong pulse light to the mother powder to carbonize the polymer coating from its surface; and The treated powder in which the polymer coating has been carbonized is discharged.

11. The powder material processing method according to claim 10, characterized in that: The air is sprayed upward at an air pressure corresponding to the gravity of the mother powder, so that the gravity of the mother powder is balanced with the suspension force, so that the mother powder is suspended at a specific height in the chamber. The processed powder that has become lighter than the mother powder due to the carbonization is discharged by the gas pressure.

12. The powder material processing method according to claim 10 or 11, characterized in that: Compressed air is supplied from a compressed air supplier to the inside of the chamber to move the mother powder into the inside of the chamber and spray the air upward.

13. The powder material processing method according to claim 10 or 11, characterized in that: The amount of mother powder supplied into the chamber and the amount of processed powder discharged to the outside of the chamber are monitored.

14. The powder material processing method according to claim 12, characterized in that: After fine dust is separated from the exhausted gas by the electric precipitator, the exhausted gas is resupplied to the compressed air supplier, thereby forming a closed loop system.

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