Methods for applying powder, apparatus for applying powder

Abstract

The objective is to provide an apparatus and method that can efficiently transport powder material to a substrate using electrostatic repulsion energy from an electron beam, and also provide energy assistance for firmly adhering the powder material. [Solution] An electron beam generated from an electron source is irradiated onto the powder material, causing the irradiated powder material to fly due to electrostatic repulsion, and the powder material directed towards the object to be attached causes the powder material to adhere to the object, thereby firmly adhering the powder material to the object in a vacuum.

Description

Technical Field

[0001] The present disclosure relates to a method and an apparatus for conveying a powder material to an adherend with high efficiency and causing the powder material to firmly adhere to the adherend. Background Art

[0002] Functional materials manufactured through a raw material composite thin-film forming process are used in various fields such as materials for various energy devices including batteries, various ceramic devices, and carbon material devices, and are indispensable for many industrial products. For example, high-capacity secondary batteries such as lithium-ion batteries are widely used in many fields because of their high energy density and ability to be repeatedly charged and discharged. Specifically, they are used in various fields including driving power sources for electric vehicles such as electric vehicles and hybrid vehicles, the mobility field such as drones, batteries for portable electronic devices such as smartphones and tablet terminals, and energy storage systems for efficiently storing and supplying electric power in cooperation with renewable energy such as photovoltaic power generation.

[0003] However, some problems have been pointed out in currently used manufacturing processes, such as safety issues caused by the use of silane gas, and heat generation and material degradation caused by the active portion of the material thin film rapidly coming into contact with oxygen and water molecules in the air when separating the material thin film from a support. Therefore, development of a method for safely manufacturing high-performance functional materials is expected.

[0004] Conventionally, a method of electrostatically adsorbing particles onto an adherend using electrostatic force has been used as a method for forming a thin film. For example, electrostatic coating is one such method, which is a coating method that coats an object using the properties of static electricity. In this method, paint fine particles are negatively charged, the charged fine particles move along lines of electric force, and adhere to the object to be coated. It is not only easy to uniformly apply the paint, but also can reduce waste of the paint, so it is used in the manufacture of automobile parts, home appliances, building materials, and the like.

[0005] Patent Document 1 discloses a method and apparatus for efficiently attaching only anions to atomizing means by magnetic force from a coil, using ions generated near a high-voltage application electrode, and causing the anions to collide with a paint liquid flow at a location away from the high-voltage application electrode, thereby obtaining negatively charged paint particles. This prevents contamination of the electrode by positively charged paint particles and significantly improves coating efficiency.

[0006] Electrostatic coating is a method used in various fields, but there are no examples of its application to the manufacture of functional materials that involve a composite thin-film formation process of raw materials performed in a vacuum. When manufacturing functional materials, the film formation process is performed in a vacuum because contact between the active part of the material thin film and oxygen or water molecules in the air can cause heat generation and material degradation. In contrast, conventional electrostatic coating assumes that the object to be coated is under atmospheric pressure, so the optimal configuration when the object to be coated (adhered object) is in a vacuum was unclear. Furthermore, because the electron beam generation part in the vacuum and the atmospheric pressure part containing the object to be coated are separated by an electron beam transmission window, it is not possible to irradiate the paint with a strong electron beam, and the technology was not efficient enough to generate enough charge to provide the strong adhesion required for film formation. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 08-024722 [Overview of the project] [Problems that the invention aims to solve]

[0008] The objective is to provide an apparatus and method that can efficiently transport powder material to a target object using the electrostatic repulsion energy generated by a powerful electron beam necessary for powder adhesion in a vacuum, and that can also provide energy assistance for firmly adhering the powder material. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing the configuration of the powder adhesion apparatus and a part of the functional material manufacturing apparatus in Embodiment 1. [Figure 2] A flowchart showing an example of a method for attaching powder in Embodiment 1. [Figure 3] A schematic diagram showing the configuration of the powder adhesion apparatus and a part of the functional material manufacturing apparatus in Embodiment 2. [Figure 4] A flowchart showing an example of a method for attaching powder in Embodiment 2. [Figure 5] A schematic diagram showing the configuration of the powder adhesion apparatus and a part of the functional material manufacturing apparatus in Embodiment 3. [Figure 6] A flowchart showing an example of a method for manufacturing a functional material in Embodiment 3. [Figure 7] A schematic diagram showing the configuration of the powder adhesion apparatus and a part of the functional material manufacturing apparatus in Embodiment 4. [Figure 8] A flowchart showing an example of a method for manufacturing a functional material in Embodiment 4. [Modes for carrying out the invention]

[0010] The following description concerns a method and apparatus for attaching powder to anode materials for high-capacity secondary batteries, particularly Si / C-based (silicon-carbon composite) anode materials. However, it goes without saying that the method and apparatus for attaching powder can be used in other applications as well. In particular, it can be suitably used in the manufacture of functional materials formed through a composite thin-film process of raw materials, for example, functional materials used as materials for various energy devices such as batteries, various ceramic devices, and carbon material devices. Specifically, it can be used not only for Si / C-based composites but also for manufacturing methods and apparatus for hydrogen storage alloys.

[0011] A method for attaching powder according to one aspect of the present invention is a method for attaching powder material to an object to be attached in a vacuum, characterized in that an electron beam generated from an electron beam source is irradiated onto the powder material, the powder material irradiated by the electron beam is scattered by electrostatic repulsion, and the powder material directed toward the object to be attached causes the powder material to be attached to the object.

[0012] Conventionally, powder materials were attached to objects in the atmosphere, but this embodiment is a method for attaching powder material to objects in a vacuum. The powder material is charged by electron beams generated from the electron source, scattered by electrostatic repulsion, and attached to the objects.

[0013] Furthermore, a powder adhesion apparatus according to one aspect of the present invention comprises an electron beam source unit arranged in a vacuum and a substrate arranged in a vacuum to which powder is to be adhered, wherein a powder material source for holding or supplying powder is arranged on a path connecting the electron beam source unit and the substrate, and a portion of the electron beam generated from the electron beam source unit is directly irradiated onto the substrate.

[0014] By placing the electron source, powder, and the object to which the powder will be attached all in a vacuum, the powder attachment process can be performed in a vacuum, preventing the material from being exposed to oxygen or water vapor and thus preventing degradation. In addition, a portion of the electron beam generated from the electron source is directly irradiated not only onto the powder but also onto the object to which the powder will be attached, resulting in a strong adhesion of the powder.

[0015] The present invention will be explained below with reference to the drawings, but it is not limited to the disclosures below and can be used as a method for attaching powders to various materials for manufacturing. [Embodiment 1] Figure 1 schematically shows a powder adhesion apparatus in Embodiment 1 and a part of a functional material manufacturing apparatus using the same. Powder is adhered to a substrate 120 along the circumferential surface of a cylindrical can 110 that circulates in a vacuum chamber 100, while being transported by an unwinding and winding device (not shown here). The substrate can be a conductive substrate, an insulating substrate, a substrate having intermediate properties, or a composite substrate that is both conductive and insulating. Powder adhesion can be performed on the substrate 120, or the cylindrical can 110 or the like can be used as the object to be adhered to directly without using a substrate. The powder material 1000 is held, for example, on a sample stage 240 and irradiated with an electron beam from an electron source unit 400.

[0016] The electron source unit 400 includes, for example, a filament 410 and an extraction electrode 420. A negative high voltage is applied to the filament 410, and at the same time, a voltage of, for example, several volts is applied to both ends of the filament, causing a current of several tens of amperes to flow through the filament and make it red-hot. Thermionic electrons generated from the red-hot filament are accelerated by the potential difference with the extraction electrode 420 and travel from the electron source unit 400 towards the powder material 1000. By applying a voltage to the sample stage 240, the potential gradient from the electron source unit to the vicinity of the powder material can be changed, thereby adjusting the energy of the electron beam reaching the powder material. In addition, a deflection coil 430 can be installed between the electron source unit 400 and the sample stage 240 to bend the trajectory of the electron beam. The deflection coil 430 has two sets of coils, and by adjusting the current flowing through the terminals of the two sets of coils, it is possible to generate two orthogonal magnetic fields and control their strength. This makes it possible to change the direction of incidence of the electron beam to the powder material and to change the amount of electron beam that reaches the substrate. The electron beam is irradiated onto the powder material 1000 to promote powder flight, and also irradiates the surface to which it is attached, thus contributing to improving the adhesion strength of the powder material.

[0017] Furthermore, an arbitrary voltage can be applied to the guide mask 440 and the cylindrical can 110. This makes it possible to optimize the kinetic energy of the powder material when it reaches the object to be attached, as well as the dispersion state and utilization efficiency of the powder material 1000 within the vacuum chamber 100.

[0018] According to the powder adhesion method of the present embodiment, both the electron beam source section, which serves as an electron beam generator, and the adherend are placed in a vacuum, and irradiation is not performed through an electron beam transmission window, so that intense electron beams can be irradiated onto the coating material. Therefore, the powder material can be efficiently charged, the surface of the adherend can also be controlled, and sufficiently intense electron beams can be irradiated, which contributes to improving the adhesion of the powder material.

[0019] Fig. 2 shows an example of a powder adhesion method using the powder adhesion device of Embodiment 1. In a vacuum, a cylindrical can that serves as an adherend or a substrate starts moving. In Fig. 1, a cylindrical can is used as the adherend, but a flat-plate substrate may also be used. After the adherend starts moving, electron beam irradiation is started. The powder is disposed in a region where the electron beam travels, and the powder is charged by the electron beam. Alternatively, the configuration may be such that the powder is supplied to the electron beam region to be charged. The powder flies and reaches the adherend and adheres thereto by electrostatic force. The electron beam is also irradiated onto the powder that has reached the adherend, so the powder is strongly bonded to the adherend. Since the powder adheres to the adherend while the adherend is moving, the powder uniformly adheres to the substrate or the cylindrical can. After the powder adheres to a desired thickness, the movement of the cylindrical can is stopped, and the cylindrical can is taken out.

[0020] An example where powder is adhered using the device of Embodiment 1 will be described. [Example 1] (1) A high voltage of -6 kV was applied to the tungsten filament of the electron beam source section, the filament was energized to cause red heat, and thermoelectrons generated thereby were used. (2) Acetylene black with a particle diameter of 1 to 10 microns was used as the powder material. The powder material was placed on a ceramic sample stage. (3) An alternating current was passed through a deflection coil, and the powder material was irradiated while the electron beam was swept substantially parallel to the surface of the sample stage. The extraction electrode was grounded. (4) A PET film with a thickness of 20 microns was used as the substrate, and was run at 1 m / min. Carbon fine powder could be adhered onto the PET substrate.

[0021] [Embodiment 2] Figure 3 schematically shows a powder adhesion apparatus in Embodiment 2 and a part of a functional material manufacturing apparatus using the same. The apparatus in Embodiment 2 is a diagram showing a configuration in which a powder supply mechanism is provided to continuously adhere the powder to the object to be adhered to over a long period of time. In the apparatus in Embodiment 1, an electron beam is irradiated onto pre-arranged powder material, but in Embodiment 2, the powder material is supplied into the field through which the electron beam passes, causing the powder to adhere to the object to be adhered.

[0022] The supply powder 480 prepared in the material hopper 450 falls while its fall rate is adjusted by the supply adjustment device 460, becoming the falling powder 500. Equipment for modifying the powder material, such as releasing agglomeration, reducing particle size, or applying a binder to the powder surface, may be incorporated into the process from the supply powder 480 to the falling powder 500. The supply amount adjustment by the supply adjustment device can be mechanical, vibratory, or various other methods. By providing the material hopper 450, a large amount of powder can be supplied and continuously attached to the object to be coated.

[0023] The falling powder 500 that reaches the electron beam field changes direction due to the electron beam and electric field, becoming flying powder 510 that adheres to the substrate 120 or other object to be attached. A portion of the falling powder 500 is not used as flying powder and is collected as recovered powder 490 in the recovery container 470. The recovered powder 490 may be reused as supply powder 480.

[0024] The electron beam is irradiated onto the falling powder 500 to promote flight, and also irradiates the surface of the object to which it is attached, thus contributing to improving the adhesion of the powder material. It is also possible to modify the powder material on the object to which it is attached. For example, if a supply powder 480 with an adhesive applied to a part of its surface is used, or if a step is included in the process of applying the adhesive to the falling powder 500, the adhesive can be immediately cured by electron beam after the adhesive-coated powder adheres to the object to which it is attached. This makes it possible to obtain a stronger adhesion force with a small amount of adhesive.

[0025] The intensity of the electron beam irradiated onto the surface to be attached can be changed by adjusting the original electron beam intensity using the filament voltage, filament current, and extraction electrode voltage of the electron beam source, but it can also be controlled by adjusting the deflection coil current to control the proportion of electron beams that reach the surface to be attached.

[0026] Figure 4 shows an example of a powder adhesion method using the powder adhesion apparatus of Embodiment 2. Similar to the method of Embodiment 1, the cylindrical can, which is the object to be adhered to, starts rotating in a vacuum. The supply powder prepared in the material hopper is adjusted in amount by a supply adjustment device to become falling powder, and during this process, modification treatments such as applying adhesive to the powder surface are performed. Electron beam irradiation is started in the direction of the object to be adhered to, and the powder is supplied as falling powder. The powder becomes charged by the electron beam and adheres to the object to be adhered to by electrostatic force upon flight. The electron beam also irradiates the powder that has reached the object to be adhered to, so it bonds strongly to the object. Once the powder has adhered to the desired thickness, the reaction is terminated.

[0027] [Example 2] An example of applying powder using the apparatus of Embodiment 2 is shown. Except for the supply of powdered material and the conditions described below, the conditions were the same as in Example 1. (1) Acetylene black placed in the material hopper of the supply device was supplied at a rate of 2 g / min into the field through which the electron beam passed using a rotary supply adjustment device. (2) A 12-micron thick PET film was used as the substrate, and the device was run at a speed of 0.2 to 3 m / min. As a result, we were able to deposit carbon fine powder onto the PET substrate. We were also able to change the amount of carbon fine powder deposited per unit area of ​​the PET film depending on the running speed of the PET film.

[0028] [Embodiment 3] Figure 5 schematically shows a powder deposition apparatus in Embodiment 3 and a part of a functional material manufacturing apparatus using the same. The powder deposition apparatus in Embodiment 3 is an example of an apparatus that performs a manufacturing method in which other vacuum film deposition processes coexist. In the powder deposition apparatus of the present invention, both the electron source unit 400 and the object to be deposited are placed in a vacuum. Therefore, it is possible to use other vacuum film deposition apparatuses simultaneously, and a process with unprecedented advantages can be constructed.

[0029] In Figure 5, when flying powder 510 adheres to the substrate 120, which travels along the circumferential surface of the cylindrical can 110 from the unwinding roll 130 to the winding roll 150, a film is immediately formed by the evaporation material 210 from the evaporation source 200. A configuration in which a portion of the vapor 520 of the evaporation material 210 and the flying powder 510 are mixed before they reach the object to be adhered to may also be used. Various evaporation sources can be used, including resistance heating evaporation sources and electron beam evaporation sources, and a sputtering film deposition source can also be used instead of an evaporation source.

[0030] The evaporation material 210 deposited on the circumferential surface of the cylindrical can forms a laminate together with the powder. The thickness of the material film is adjusted to the desired thickness by the evaporation rate of the evaporation material and the rotation speed of the cylindrical can. Furthermore, the thin film does not necessarily have to be a continuous film; it may be a perforated thin film or a discontinuous thin film. It may also have irregularities. By providing a shutter at the evaporation source, the timing of film formation can be controlled.

[0031] As soon as the flying powder 510 adheres to the substrate 120, or immediately afterward, the vapor 520 from the evaporating material 210 arrives, causing the flying powder to quickly integrate with the evaporating material and become fixed to the object it adheres to. This significantly reduces the risk of the flying powder detaching and falling from the object it adheres to.

[0032] Figure 6 shows an example of a method for manufacturing a functional material by attaching powder using the powder attachment apparatus of Embodiment 3. In a vacuum, a cylindrical can, which is the object to be attached, starts to rotate, and the substrate moves. Similar to the method of Embodiment 2, the supply powder prepared in the material hopper is adjusted by a supply adjustment device to become falling powder, and during this process, adhesives or the like may be applied to the surface of the powder. Electron beam irradiation is started in the direction of the object to be attached, and the powder is supplied as falling powder. The powder is charged by the electron beam and flies to the object to be attached. The flying powder 510 is deposited by an evaporation material 210 heated on an evaporation source 200 before or after it adheres to the object to be attached. If the object to be attached is a substrate moving along a cylindrical can, a vapor-deposited film is formed on the powder layer due to the rotation of the cylindrical can. The formation of the powder layer and the deposition of the film can be repeated until the desired thickness is reached. The formed film-like functional material is peeled off and recovered from the object to be attached, and the reaction is terminated.

[0033] [Example 3] This example shows how a functional material was manufactured by applying powder using the apparatus of Embodiment 3. As shown in Figure 5, the equipment configuration was the same as in Embodiment 2, but with the addition of a vacuum deposition source. Except as described below, the procedure was the same as in Embodiment 2. A 270-degree deflected electron beam evaporation source was used as the evaporation source, and silicon was used as the evaporation material. A 25-micron thick polyimide substrate was used as the substrate, and by performing powder deposition and vacuum deposition simultaneously, it was possible to increase the adhesion strength of acetylene black fine powder on the polyimide substrate compared to when powder deposition was performed alone.

[0034] [Embodiment 4] Figure 7 schematically shows a powder adhesion apparatus in Embodiment 4 and a part of a functional material manufacturing apparatus using the same. In the apparatus of Figure 7, lamination can be performed by repeatedly directly adhering powder and vacuum deposition onto a cylindrical can 110 without using a substrate. The powder adhesion apparatus of Embodiment 4 shows an example of an apparatus that performs a manufacturing method in which other vacuum deposition processes coexist. The powder adhesion method of the present invention is performed in an apparatus in which both the electron source unit 400 and the object to be adhered are placed in a vacuum. By performing this adhesion method and other vacuum deposition processes simultaneously, it is possible to construct a process with unprecedented advantages.

[0035] In Embodiment 4, after repeatedly laminating powder and vapor-deposited film on a cylindrical can 110 a predetermined number of times, the laminated film is peeled off the cylindrical can 110 by a blade 600 or the like and stored in a catcher 610. In the peeling process, the laminate may be subjected to CVD film deposition by the CVD functional unit 300. By performing CVD film deposition while peeling off the laminate, the surface of the powder and peeled pieces is subjected to CVD film deposition, which prevents deterioration when the functional material is taken out into the atmosphere. The apparatus in Figure 7 is an apparatus that can perform the powder adhesion process and the vacuum film deposition process simultaneously, which was previously difficult.

[0036] Figure 8 shows an example of a method for manufacturing a functional material by attaching powder using the apparatus of Embodiment 4. The cylindrical can, which is the object to be attached, starts rotating in a vacuum. Similar to the method of Embodiment 2, the supply powder prepared in the material hopper is adjusted in amount by a supply adjustment device to become falling powder, and adhesives or the like may be applied to the surface of the powder during this process. Electron beam irradiation is started in the direction of the object to be attached, and the powder is supplied as falling powder. The powder is charged by the electron beam and flies to the object to be attached. The flying powder 510 is deposited by the evaporation material 210 heated on the evaporation source 200 before or after it adheres to the object to be attached. Due to the rotation of the object to be attached, such as a cylindrical can, a vapor-deposited film is formed on the powder layer. The formation of the powder layer and the film formation by vapor deposition can be repeated until the desired thickness is reached. After the laminate is formed to the desired thickness, the blade 600 moves to a position where it can scrape off the laminate on the cylindrical can. The laminate formed on the cylindrical can is scraped off by the blade while a CVD film is deposited by the CVD functional unit. The functional material, which has been peeled and pulverized by the blade, is collected from the attached material into the catcher 610, and the reaction ends.

[0037] [Example 4] This example shows how a functional material was manufactured by applying powder using the apparatus of Embodiment 4. The release powder was obtained using the equipment configuration shown in Figure 7. Unlike Embodiment 3, the powder material and vapor deposition material were directly deposited onto the circumferential surface of a cylindrical can, rather than on a polymer film. After the cylindrical can was rotated to perform lamination, the deposited material on the circumferential surface of the cylindrical can was scraped off with a scraper while CVD film deposition was performed and the material was recovered. Elemental analysis revealed that the release powder contained the powder material and vapor deposition material. The release powder could be further pulverized by a grinding process.

[0038] According to this disclosure, the electrostatic repulsion energy from a powerful electron beam irradiated in a vacuum allows for highly efficient transport of powder material to the object to be attached, and electron beam assistance can be provided at the attachment site as needed, enabling firm adhesion of the powder material. [Explanation of Symbols]

[0039] 100 vacuum chamber 110 Cylindrical Can 120 circuit boards 130 unwinding rolls 140 Guide Rollers 150 rolls 200 Evaporation source 210 Evaporation materials 240 Sample stage 250 Film deposition source 300 CVD Functional Unit 400 Electron beam source section 410 filaments 420 Extraction electrodes 430 Deflection coil 440 Guide Mask 450 Material Hopper 460 Supply adjustment device 470 collection containers 480 Feed powder 490 Recovered Powder 500 Fallen Powder 510 Flying Powder 520 steam 600 blades 610 Catcher 1000 powder material 2000 Manufacturing equipment

Claims

1. A method for attaching powder material to an object to be attached in a vacuum, The electron beam generated from the electron source is irradiated onto the powder material. The powder material irradiated with the electron beam is propelled by electrostatic repulsion, A method for attaching powder, wherein the powder material is directed toward the object to be attached, thereby causing the powder material to adhere to the object.

2. The object to be attached is positioned on the extension of the irradiation direction of the electron beam generated from the electron source, The method for attaching powder according to claim 1, characterized in that the powder material before flight is placed between the electron source and the object to be attached.

3. The method for attaching powder according to claim 2, characterized in that the powder material before flight is held on an insulating sample stage positioned between the electron source and the object to be attached.

4. The method for attaching powder according to claim 1, characterized in that a portion of the electron beam is irradiated substantially parallel to the surface of the insulating sample stage that holds the powder material, near the surface of the insulating sample stage.

5. The method for attaching powder according to claim 1, wherein the powder material is attached to the object to be attached while the electron beam generated from the electron beam source unit is supplied along the path to the object to be attached.

6. The method for attaching powder according to claim 1, characterized in that a portion of the electron beam directly reaches the vicinity of the powder material attachment position on the object to be attached.

7. The method for attaching powder according to claim 1, characterized in that the amount of powder reaching the object to be attached is adjusted by deflecting the electron beam by a magnetic field scan generated by a deflection coil before it reaches the object to be attached.

8. The method for attaching powder according to claim 1, characterized in that the amount of electron beam reaching the object to be attached is adjusted by deflecting the electron beam by a magnetic field scan generated by a deflection coil before it reaches the object to be attached.

9. An electron beam source placed in a vacuum, It comprises an object to which powder is attached, which is placed in a vacuum, A powder material source that holds or supplies powder is arranged on the path connecting the electron beam source and the object to be attached. A powder adhesion apparatus characterized in that a portion of the electron beam generated from the electron source is directly irradiated onto the object to be adhered.

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