Powder coating equipment

Abstract

This powder coating device comprises a first stage squeegee (11) and a second stage squeegee (12) which adjust the thickness of supplied powder (3), wherein: the first stage squeegee (11) and the second stage squeegee (12) are subjected to a natural vibration at frequencies from 2 kHz to 300kHz inclusive; and the second stage squeegee (12) is offset by a quarter wavelength of the natural vibration with respect to the first stage squeegee (11) in the width direction of the powder (3) supplied to the surface of a sheet (4).

Description

[Technical Field]

[0001] This disclosure relates to a powder coating apparatus. [Background technology]

[0002] In recent years, dry coating methods, which involve directly applying powder, have attracted attention as a method that can form a high-performance powder layer with a lower environmental impact compared to wet coating methods, which involve dispersing powder in a solvent. This is because dry coating methods result in less material damage from the solvent, maintain high performance, eliminate the need to dry the solvent, and allow for the creation of a powder layer that significantly reduces energy consumption.

[0003] Conventionally, a known method for dry coating with powder involves coating the surface of a component, such as metal foil, with powder while the component is being transported by a conveying device.

[0004] For example, Patent Document 1 discloses a technique for coating the surface of a long metal foil with powder. Patent Document 1 describes adjusting the thickness of the powder uniformly by supplying the powder onto the surface of the metal foil and then flattening the powder with a squeegee. Figure 5 shows a squeegee 26 of a conventional powder coating apparatus 21, and Figure 6 shows a view of the squeegee 26 of the conventional powder coating apparatus 21 from above and a view of the coated powder layer 25 from the front. Figure 6(a) shows the case where the squeegee 26 vibrates naturally with a sinusoidal standing wave (shown as viewed from the front) when viewed from above. Figure 6(b) shows a view of the powder layer 25 coated on a sheet 24 from the front.

[0005] As shown in Figure 5, the squeegee 26 vibrates at a high frequency near the ultrasonic band (frequency between 2kHz and 300kHz), and the vibration is transmitted to the powder 23, improving the fluidity of the powder 23, thereby achieving coating without powder blockage.

[0006] As shown in Figure 6(a), when the squeegee 26 is vibrated at a high frequency, it vibrates in a sinusoidal standing wave manner due to its natural vibration. As a result, a sinusoidal standing wave-shaped uneven structure is formed in the powder layer 25 that passes through the gap of the squeegee 26, as shown in Figure 6(b). [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-178271 [Overview of the project]

[0008] The powder coating apparatus of the present disclosure comprises a drive device for moving a member in a predetermined direction, a powder supply device for supplying powder to the surface of the member, and a first squeegee and a second squeegee arranged to form a gap between themselves and the member and adjusting the thickness of the powder supplied to the surface of the member by the powder supply device, wherein the first squeegee and the second squeegee vibrate naturally at a frequency of 2 kHz or more and 300 kHz or less, the first squeegee is located on the powder supply side of the second squeegee, and the second squeegee is offset from the first squeegee by a quarter wavelength of the natural vibration along the width direction of the powder supplied to the surface of the member. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing a powder coating apparatus according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic diagram showing a part of a powder coating apparatus and a powder layer according to one embodiment of the present disclosure. [Figure 3] Figure 3 is a schematic diagram showing a part of a powder coating apparatus and a powder layer according to one embodiment of the present disclosure. [Figure 4] Figure 4 is a schematic diagram showing a part of a powder coating apparatus according to one embodiment of the present disclosure. [Figure 5]FIG. 5 is a schematic view showing a part of a conventional powder coating apparatus. [Figure 6] FIG. 6 is a schematic view showing a part of a conventional powder coating apparatus and a powder layer.

Embodiments for Carrying Out the Invention

[0010] In the technique disclosed in Patent Document 1, there is a variation in the basis weight in the coating width direction in the powder layer, and there is room for improvement when uniformity is required.

[0011] An object of the present disclosure is to provide a powder coating apparatus capable of reducing the variation in basis weight caused by the uneven structure scraped into a sinusoidal steady-wave shape on the surface of the powder layer.

[0012] In addition, each of the embodiments described below shows general or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, order of steps, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0013] In addition, each figure is a schematic diagram and is not necessarily drawn precisely. Also, in each figure, the same reference numerals are given to the same components.

[0014] (Overview) The powder coating apparatus of the present disclosure includes a driving device that moves a member in a predetermined direction, a powder supply device that supplies powder to the surface of the member, and a plurality of squeegees that are arranged so as to form a gap (hereinafter also referred to as a gap) between the member and adjust the thickness and basis weight of the powder supplied to the surface of the member by the powder supply device. Further, the plurality of squeegees vibrate at a natural frequency of 2 kHz or more and 300 kHz or less. When the plurality of squeegees include a first squeegee and a second squeegee, the first squeegee is located on the powder supply side with respect to the second squeegee. And the second squeegee is displaced by a quarter wavelength when vibrating naturally along the width direction of the powder supplied to the surface of the member with respect to the first squeegee.

[0015] Thereby, the first squeegee and the second squeegee vibrate at a high frequency near the ultrasonic band (frequency: 2 kHz or more and 300 kHz), and the vibration is transmitted to the powder to improve the fluidity of the powder, so that coating without powder clogging can be realized.

[0016] Further, when the first squeegee and the second squeegee are vibrated at a high frequency, the first squeegee and the second squeegee vibrate naturally with a sinusoidal steady wave. Thereby, the surfaces of the powder layers passing through the gaps between the first squeegee and the member and between the second squeegee and the member respectively have a shape scraped into a sinusoidal steady wave shape. For this reason, by shifting the second squeegee by a quarter wavelength of natural vibration with respect to the first squeegee and arranging the first squeegee and the second squeegee in two rows side by side in the traveling direction, the second squeegee can scrape off the portion where the basis weight was large with the first squeegee. As a result, the variation in the basis weight of the powder layer in the width direction can be reduced.

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0018] (Embodiment) Hereinafter, embodiments will be described with reference to FIGS. 1 to 4.

[0019] Figure 1 is a schematic diagram showing a powder coating apparatus 1 according to one embodiment of the present disclosure, Figures 2 and 3 are schematic diagrams showing a part of the powder coating apparatus 1 and the powder layer 5 according to one embodiment of the present disclosure, and Figure 4 is a schematic diagram showing a part of the powder coating apparatus 1 according to one embodiment of the present disclosure. Figure 2(a) shows the case when the first-stage squeegee 11 and the second-stage squeegee 12 vibrate naturally in a sinusoidal standing wave (shown as viewed from the front) when viewed from above. Figure 2(b) shows the powder layer 5 coated on the sheet 4 as viewed from the front. Figure 3(a) shows the first-stage squeegee 11 and the second-stage squeegee 12 and the powder layer 5 as viewed from the side. Figure 3(b) shows the first-stage squeegee 11 and the second-stage squeegee 12 and the powder layer 5 coated on the sheet 4 as viewed from the front. Figure 4 shows the case where the first-stage squeegee 11, second-stage squeegee 12, third-stage squeegee 13, and fourth-stage squeegee 14 vibrate naturally in a sinusoidal standing wave (as seen from the front).

[0020] [Powder coating equipment] As shown in Figure 1, the powder coating apparatus 1 comprises a conveying device (not shown) which is a drive device, a powder supply device (not shown), a first-stage squeegee 11 that vibrates at high frequency, and a second-stage squeegee 12 that vibrates at high frequency. The first-stage squeegee 11 is an example of a first squeegee. The second-stage squeegee 12 is an example of a second squeegee.

[0021] A conveying device transports a sheet-like material (hereinafter also referred to as sheet 4) along the direction of travel. The powder coating device 1 continuously supplies powder 3 to the surface of the sheet 4 being transported using a powder supply device. The powder coating device 1 then uses a first-stage squeegee 11 and a second-stage squeegee 12 to adjust the film thickness and filling rate of the powder 3 supplied to the surface of sheet 4, thereby creating a powder layer 5 with a desired basis weight while minimizing variations in basis weight.

[0022] The powder 3 is first leveled by the first-stage squeegee 11, and then further leveled by the second-stage squeegee 12.

[0023] Here, basis weight refers to the amount of powder per unit area expressed in weight, and the unit of basis weight is, for example, g / cm². 2 This is shown.

[0024] Furthermore, the conveying device is not particularly limited and can be any device that can convey the sheet 4. For example, the conveying device may be one that can continuously unwind the sheet 4 wound in a roll shape, or one that can unwind the sheet 4 intermittently.

[0025] Furthermore, guide rollers that rotate as the sheet 4 moves, and control devices that correct the meandering of the sheet 4 may be provided along the transport path of the sheet 4.

[0026] In this embodiment, the sheet 4 is a long, strip-shaped thin sheet that is wound up. However, the sheet 4 is not limited to a long, strip-shaped thin sheet. For example, a sheet 4 of a desired shape may be unwound from the conveying device, the coating of the powder 3 onto the sheet 4 may be completed, and then a new sheet 4 may be unwound from the conveying device. Also, the sheet 4 does not have to be wound up in a roll shape. In other words, the sheet 4 only needs to be in a shape that allows the powder 3 to be coated using the powder coating device 1. Therefore, the shape of the sheet 4 is not particularly limited. Furthermore, in this embodiment, the sheet 4 is a current collector containing metal foil, but the material of the component is not particularly limited. In other words, the sheet 4 can be any component that allows the powder 3 to be coated using the powder coating device 1.

[0027] Powder 3 can be any powdery substance. In other words, the raw materials, composition, and particle shape of powder 3 are not particularly limited. In this embodiment, powder 3 is a group of particles containing a solid electrolyte.

[0028] The powder 3 preferably has an average particle size (D50) of 0.005 μm or more and 30 μm or less. In this case, the fluidity of the powder 3 tends to decrease, but the vibration of the first-stage squeegee 11 and the second-stage squeegee 12 suppresses the accumulation and aggregation of the powder 3, so that a powder layer 5 with little variation in basis weight can be formed. Here, the average particle size (D50) is the volume-based median diameter calculated from the measured particle size distribution by the laser diffraction and scattering method. This average particle size (D50) can be measured using a commercially available laser analysis and scattering type particle size distribution analyzer.

[0029] Furthermore, powder 3 may contain only one type of powder, or it may contain two or more types of powder.

[0030] In this embodiment, a hopper is used as the powder supply device. The hopper stores the powder 3 inside and supplies the powder 3 to the surface of the sheet 4. The hopper is positioned upstream of the first-stage squeegee 11 and the second-stage squeegee 12 in the direction of travel of the sheet 4. The powder 3 supplied to the surface of the sheet 4 reaches the second-stage squeegee 12 via the first-stage squeegee 11 as the sheet 4 moves. In this embodiment, a hopper is used as the powder supply device, but it is not limited to this, and any device capable of supplying powder 3 to the surface of the sheet 4 may be used as the powder supply device.

[0031] A predetermined gap is formed between the first-stage squeegee 11 and the second-stage squeegee 12 and the sheet 4. The powder 3 supplied to the surface of the sheet 4 passes through this gap. As the powder 3 passes through the gap, the first-stage squeegee 11 and the second-stage squeegee 12 adjust the film thickness and packing density of the powder 3 supplied to the surface of the sheet 4, reducing variations in the basis weight of the powder layer 5.

[0032] (High-frequency vibrations near the ultrasonic band) The first-stage squeegee 11 and the second-stage squeegee 12 vibrate at a frequency between 2 kHz and 300 kHz. In other words, the first-stage squeegee 11 and the second-stage squeegee 12 vibrate at high frequencies near the ultrasonic band. Specifically, when the powder 3 supplied to the surface of the sheet 4 passes through the gaps between the first-stage squeegee 11 and the second-stage squeegee 12 and the sheet 4, the vibration of the first-stage squeegee 11 and the second-stage squeegee 12 at high frequencies near the ultrasonic band increases the fluidity of the powder 3 in the powder layer 5. As a result, powder clogging is suppressed.

[0033] The fluidity of powder 3 tends to increase with higher vibration frequencies of the first-stage squeegee 11 and the second-stage squeegee 12. Therefore, by vibrating the first-stage squeegee 11 and the second-stage squeegee 12 at frequencies of 2 kHz or higher in the high-frequency region near the ultrasonic band, the fluidity of powder 3 can be sufficiently increased. However, if the frequency is too high, the high frequencies near the ultrasonic band tend to attenuate, making it difficult for the vibrations of the first-stage squeegee 11 and the second-stage squeegee 12 to be transmitted to powder 3. However, if the frequency is 300 kHz or lower, the fluidity of powder 3 can be sufficiently increased. By vibrating the first-stage squeegee 11 and the second-stage squeegee 12 at high frequencies near the ultrasonic band, the powder 3 in contact with the first-stage squeegee 11 and the second-stage squeegee 12 is less susceptible to frictional resistance due to powder pressure, increasing its fluidity and suppressing the accumulation and aggregation of powder 3.

[0034] Furthermore, with respect to the powder 3 located near the first-stage squeegee 11 and the second-stage squeegee 12, the vibration effect of the first-stage squeegee 11 and the second-stage squeegee 12 reduces the frictional force between the powder particles and increases fluidity, thereby suppressing the aggregation of the powder 3.

[0035] As a result, even when using powder 3 with a particle size of 30 μm or less and low fluidity, the vibrating first-stage squeegee 11 and second-stage squeegee 12 allow the powder 3 to pass through the aforementioned gap without stagnation or agglomeration.

[0036] (Natural vibrations of the first-stage squeegee 11 and the second-stage squeegee 12, and the arrangement of the first-stage squeegee 11 and the second-stage squeegee 12) When the first-stage squeegee 11 and the second-stage squeegee 12 are vibrated at a high frequency near the ultrasonic band, the first-stage squeegee 11 and the second-stage squeegee 12 vibrate in their natural vibration (resonant state), and the first-stage squeegee 11 and the second-stage squeegee 12 vibrate in a sinusoidal standing wave.

[0037] As shown in Figure 2(a), the first-stage squeegee 11 and the second-stage squeegee 12 are positioned such that, when viewed from the front, the antinodes of the sinusoidal standing wave of the first-stage squeegee 11 correspond to the nodes of the sinusoidal standing wave of the second-stage squeegee 12. In other words, the first-stage squeegee 11 and the second-stage squeegee 12 are positioned such that the nodes of the sinusoidal standing wave of the first-stage squeegee 11 correspond to the antinodes of the sinusoidal standing wave of the second-stage squeegee 12.

[0038] Specifically, a first-stage squeegee 11 and a second-stage squeegee 12 of the same shape are prepared and vibrated in the same natural vibration state. Here, the same natural vibration state means that the positions of the antinodes and nodules correspond to the same position. For example, this state can be achieved by operating the first-stage squeegee 11 and the second-stage squeegee 12 at the same frequency. Specifically, this state can be achieved by arranging the first-stage squeegee 11 and the second-stage squeegee 12 in parallel in this order along the direction of propagation of the powder layer 5, and then shifting the second-stage squeegee 12 relative to the first-stage squeegee 11 by one-quarter wavelength of the natural vibration in the width direction of the powder 3, that is, along the width direction of the powder layer 5. The width direction of the powder layer 5 is perpendicular to the direction of propagation.

[0039] As a result, as shown in Figure 2(b), it is possible to perform coating with less variation in the basis weight of the powder layer 5 compared to conventional methods. Consequently, a high-quality powder layer 5 can be formed.

[0040] Let me explain the reason. First, the powder layer 5 is coated by scraping off the surface in accordance with the shape of the sinusoidal standing wave of the first-stage squeegee 11. The antinodes of the sinusoidal standing wave of the first-stage squeegee 11 vibrate much more than the nodal parts, where the amplitude is almost zero. As a result, the powder layer 5 corresponding to the antinodes is scraped off more than the powder layer 5 corresponding to the nodal parts when it passes through the gap between the first-stage squeegee 11 and the sheet 4.

[0041] However, the second squeegee 12 scrapes off the portion of the powder layer 5 where the first squeegee 11 had a high powder basis weight, that is, the portion of the powder layer 5 that passed through the nodal portion of the first squeegee 11 (hereinafter also referred to as the peak portion). The scraped-off peak portion of the powder layer 5 compensates for the portion of the powder layer 5 where the first squeegee 11 had a low basis weight, that is, the portion of the powder layer 5 that passed through the belly portion of the first squeegee 11 (hereinafter also referred to as the valley portion). Therefore, it is possible to perform coating with small variations in the basis weight of the powder layer 5.

[0042] Furthermore, it is preferable that the amplitudes of the first-stage squeegee 11 and the second-stage squeegee 12 are such that the amplitude of the first-stage squeegee 11 is greater than or equal to the amplitude of the second-stage squeegee 12. In other words, the amplitude of the first-stage squeegee 11 is greater than or equal to the amplitude of the second-stage squeegee 12. This is because if the amplitude of the second-stage squeegee 12 is the same as the amplitude of the first-stage squeegee 11, or if the amplitude of the second-stage squeegee 12 is smaller than the amplitude of the first-stage squeegee 11, the coating result of the first-stage squeegee 11 will not be completely reset. As a result, the variation in the basis weight of the powder layer 5 can be reduced by the combined action of both the first-stage squeegee 11 and the second-stage squeegee 12.

[0043] Furthermore, it is preferable that the amplitude of the second-stage squeegee 12 be one-quarter to three-quarters of the amplitude of the first-stage squeegee 11. By setting the amplitude of the second-stage squeegee 12 to one-quarter to three-quarters of that of the first-stage squeegee 11, the second-stage squeegee 12 scrapes off the peak portion of the powder layer 5 after the first-stage squeegee 11, and the powder 3 scraped off from the peak portion is replenished in the valley portion of the powder layer 5. This improves the balance between the peak portion after scraping and the valley portion after replenishment. As a result, variations in the basis weight of the powder layer 5 can be further reduced.

[0044] The following describes the gap between the first-stage squeegee 11 and the second-stage squeegee 12 and the sheet 4.

[0045] As shown in Figure 3(a), if the first gap between the first-stage squeegee 11 and the sheet 4 is h1, and the second gap between the second-stage squeegee 12 and the sheet 4 is h2, it is preferable that the relationship h1 ≤ h2 holds. In other words, the first gap between the first-stage squeegee 11 and the sheet 4 is less than or equal to the second gap between the second-stage squeegee 12 and the sheet 4. This is because making the second gap of the second-stage squeegee 12 the same as the first gap of the first-stage squeegee 11, or making the second gap of the second-stage squeegee 12 wider than the first gap of the first-stage squeegee 11, does not completely reset the coating result of the first-stage squeegee 11. As a result, the variation in the basis weight of the powder layer 5 can be reduced by the combined action of both the first-stage squeegee 11 and the second-stage squeegee 12.

[0046] Furthermore, if the amplitudes of the sinusoidal standing waves of the first-stage squeegee 11 and the second-stage squeegee 12 are the same, it is preferable that the second gap of the second-stage squeegee 12 be wider than the first gap of the first-stage squeegee 11 by one-quarter to three-quarters of its amplitude. By making the amplitude of the second-stage squeegee 12 wider than that of the first-stage squeegee 11 by one-quarter to three-quarters, the second-stage squeegee 12 scrapes off the peak portion of the powder layer 5 after the first-stage squeegee 11, and the powder 3 scraped off from the peak portion is replenished in the valley portion of the powder layer 5. This improves the balance between the peak portion after scraping and the valley portion after replenishment. As a result, variations in the basis weight of the powder layer 5 can be further reduced.

[0047] Furthermore, as shown in Figure 2(b), by scraping off the powder 3 from the parts of the powder layer 5 that had a high basis weight after passing through the gaps of the first squeegee 11 and the second squeegee 12, and supplementing the parts with a low basis weight with powder 3, the variation in the basis weight of the powder layer 5 can be further reduced.

[0048] Furthermore, a preliminary squeegee may be provided in front of the first-stage squeegee 11 (on the powder supply device side) to roughly adjust the thickness of the powder layer 5 in advance, and in the preliminary squeegee, the gap between the squeegee and the sheet may be wider at the front (on the powder supply side). This is because the thickness of the powder layer 5 is roughly adjusted and the basis weight is adjusted, and normally the basis weight is reduced while thinning the thickness of the powder layer 5.

[0049] Furthermore, as shown in Figure 4, a third-stage squeegee 13 may be provided behind the second-stage squeegee 12. In other words, the third-stage squeegee 13 may be positioned on the opposite side of the second-stage squeegee 12 from the first-stage squeegee 11 side. In this case, the third-stage squeegee 13 is positioned offset from the second-stage squeegee 12 by one-eighth of a wavelength of its natural vibration along the width direction of the powder 3, that is, along the width direction of the powder layer 5. The third-stage squeegee 13 is an example of a third squeegee.

[0050] In this way, the third squeegee 13 can scrape off every other portion of the powder layer 5 with a high base weight after passing through the gap of the first squeegee 11 and the gap of the second squeegee 12, and can replenish the portions with a low base weight with powder 3.

[0051] Furthermore, a fourth-stage squeegee 14 may be provided behind the third-stage squeegee 13. In other words, the fourth-stage squeegee 14 may be positioned on the opposite side of the third-stage squeegee 13 from the second-stage squeegee 12. In this case, the fourth-stage squeegee 14 is positioned in the opposite direction to the third-stage squeegee 13, which is positioned offset from the second-stage squeegee 12 by one-eighth of a wavelength of natural vibration, along the width direction of the powder layer 5, relative to the second-stage squeegee 12. The fourth-stage squeegee 14 is an example of a fourth squeegee.

[0052] By doing this, the fourth squeegee 14 can scrape off all of the parts of the powder layer 5 with a high base weight after passing through the gaps of the first squeegee 11 and the second squeegee 12, and can further supplement the parts with a low base weight with powder 3.

[0053] Specifically, four squeegees—a first-stage squeegee 11, a second-stage squeegee 12, a third-stage squeegee 13, and a fourth-stage squeegee 14—of the same shape are prepared, made to vibrate naturally at the same frequency, and then arranged with a staggered configuration as described above.

[0054] (Direction and magnitude of high-frequency vibrations near the ultrasonic band, and squeegee shape) The high-frequency vibration direction of the squeegee near the ultrasonic band includes at least one of a vertical component and a horizontal component. That is, the squeegee vibrates in at least one of the vertical or horizontal directions. Here, "squeegee" refers collectively to the first-stage squeegee 11, second-stage squeegee 12, third-stage squeegee 13, and fourth-stage squeegee 14 described above.

[0055] The vertical direction refers to the direction perpendicular to the main surface of the squeegee (the surface on which the squeegee contacts the powder). Vibrations in the vertical direction are easily transmitted to the powder 3 as longitudinal waves (waves in the direction of vibration where the squeegee moves closer to and further away from the powder 3).

[0056] The vertical component has a significant effect on reducing frictional resistance between the powder particles 3. This is because vertical vibrations are in a direction that moves the squeegee closer to and further away from the powder particles 3, causing repeated collisions between the particles 3 and making it easier for the vibrations to be transmitted to the powder particles 3. High frequencies near the ultrasonic band have high frequencies, which may make it difficult for vibrations to be transmitted between the powder particles 3, but vertical vibrations are particularly effective in transmitting vibrations to the powder particles 3.

[0057] Here, the horizontal direction is the direction parallel to the main surface of the squeegee and also parallel to the axis of the squeegee. Horizontal vibrations are easily transmitted to the powder 3 as transverse waves (waves in the direction in which the squeegee vibrates as it rubs against the powder 3). Here, the axis of the squeegee means the axis parallel to the width direction of the sheet 4. The axis of the squeegee may also be parallel to the longitudinal direction of the squeegee.

[0058] The horizontal component of the high-frequency vibration of the squeegee near the ultrasonic band contributes significantly to reducing not only the frictional resistance between the powder particles 3, but also the frictional force between the squeegee and the powder particles 3. If the vertical vibration component is too large, the vibration will be transmitted too much to the powder particles 3, causing them to vibrate excessively and potentially leading to large variations in film thickness. However, since the horizontal vibration component can also reduce the frictional force between the squeegee and the powder particles 3, the fluidity of the powder particles 3 can be particularly improved. Furthermore, horizontal vibration of the squeegee can be achieved by attaching a high-frequency transducer in the axial direction of the squeegee and supporting the end of the squeegee with a bearing, which allows for a simpler apparatus structure compared to vibration in the planar direction.

[0059] The direction of the high-frequency vibration near the ultrasonic band of the squeegee may be vertical only, or horizontal only. However, if high-frequency vibration near the ultrasonic band is used in combination with both vertical and horizontal directions, the fluidity of the powder 3 can be further improved. For example, if we focus on a single powder 3, the vibration direction of the powder 3 becomes random, and vibration is applied to the entire surface of the powder 3. As a result, there are no surfaces where vibration is not transmitted and frictional resistance is high, and the fluidity of the powder 3 is improved.

[0060] When the squeegee vibrates in the vertical and horizontal directions at high frequencies near the ultrasonic band, it is preferable that the magnitude of the horizontal vibration of the squeegee is greater than the magnitude of the vertical vibration of the squeegee. In other words, it is preferable that the magnitude of the transverse wave component of the powder 3 (the direction in which the squeegee vibrates as it rubs against the powder 3) is greater than the magnitude of the longitudinal wave component of the powder 3 (the direction in which the squeegee vibrates as it moves closer to and away from the powder 3). In this case, the frictional resistance at the interface between the squeegee and the powder 3, where frictional resistance tends to be particularly high, can be reduced by the horizontal vibration of the squeegee, and the frictional resistance between the powder particles 3 can also be reduced. As a result, the fluidity of the powder 3 can be further improved.

[0061] The magnitude of the vertical vibration of the squeegee is preferably 2 μm or more. That is, the vertical amplitude of the squeegee is preferably 2 μm or more. In this case, the frictional resistance between the powder particles 3 can be sufficiently reduced, and the fluidity of the powder particles 3 can be further increased. In this case, the vertical amplitude of the squeegee is preferably, for example, 20 μm or less. This prevents the powder particles 3 from vibrating too much, which would cause them to scatter as dust and contaminate the surroundings.

[0062] The magnitude of the horizontal vibration of the squeegee is preferably 4 μm or more. That is, the horizontal amplitude of the squeegee is preferably 4 μm or more. In this case, the frictional resistance at the interface between the squeegee and the powder 3 can be sufficiently reduced, and the fluidity of the powder 3 can be further increased. In this case, the horizontal amplitude of the squeegee is preferably, for example, 40 μm or less. This prevents the powder 3 from vibrating too much, which would cause the powder 3 to scatter as dust and contaminate the surroundings.

[0063] The squeegee is, for example, cylindrical, and is positioned such that its axial direction (the height direction of the cylinder) is parallel to the top surface of the sheet 4 and intersects (for example, perpendicular to) the direction of movement of the sheet 4. The cylindrical squeegee is positioned with both ends of the squeegee in the axial direction fixed by bearing-equipped supports so that it slides horizontally. The amount of horizontal sliding can be adjusted by equipping the squeegee with a stopper or the like. In addition, the squeegee's axis can be inserted into the diameter of a circular bearing, and the amount of vertical vibration can be adjusted by adjusting the difference between the squeegee diameter and the bearing diameter. Thus, a relationship can be created in which the horizontal amplitude is greater than the vertical amplitude.

[0064] [Method for manufacturing the powder layer] The method for manufacturing the powder layer 5 is described below. The powder layer 5 can be manufactured using the powder coating apparatus 1.

[0065] The method for manufacturing the powder layer 5 includes supplying powder 3 to the surface of a sheet 4, such as a current collector, while moving the sheet 4 in a predetermined direction (powder supply step), and adjusting the thickness and basis weight of the powder 3 supplied to the surface of the sheet 4 using a first-stage squeegee 11 and a second-stage squeegee 12 (powder alignment step).

[0066] First, powder 3 is prepared. The raw materials for powder 3 are not particularly limited, but for example, a group of particles containing an active material may be used. Powder 3 is prepared by mixing the active material and binder with appropriate additives (for example, a conductive material). Mixing methods include, for example, using a mortar and pestle, a ball mill, or a mixer. In particular, a method of mixing powder 3 without using solvents is preferred as it does not cause material degradation.

[0067] In the powder supply process, the sheet 4 is moved in a predetermined direction while the powder 3 is supplied to the surface of the sheet 4 using a powder supply device such as a hopper. The sheet 4 may be in a shape other than a sheet, for example, a plate or a block. In this case, the plates and blocks may be fed intermittently.

[0068] The powder alignment process is a process of aligning the powder 3 onto the surface of the sheet 4 using the first-stage squeegee 11 and the second-stage squeegee 12 of the powder coating apparatus 1. In other words, in the powder alignment process, the thickness and basis weight of the powder 3 supplied to the surface of the sheet 4 are adjusted using the first-stage squeegee 11 and the second-stage squeegee 12. At this time, the first-stage squeegee 11 and the second-stage squeegee 12 vibrate at a frequency of 2 kHz to 300 kHz. The first-stage squeegee 11 and the second-stage squeegee 12 are positioned such that their positions are shifted by one-quarter wavelength of their natural vibration with respect to the coating width direction.

[0069] The method for manufacturing the powder layer 5 may further include a powder sheeting step. The powder sheeting step is a step of compressing the powder 3 aligned on the sheet 4 using the roll press of the powder coating apparatus 1. As a result, a compressed powder layer is formed on the surface of the sheet 4 by compressing the powder layer 5.

[0070] As described above, in the method for manufacturing the powder layer 5, by performing the powder supply step and the powder alignment step in this order, a powder layer 5 composed of powder 3 is formed on the surface of the sheet 4. Such a laminate of sheet 4 and powder layer 5 can be used in energy devices. For example, when a current collector is used as sheet 4 and an active material is used as powder 3, electrodes for energy devices can be manufactured.

[0071] Energy devices manufactured using the powder coating apparatus 1 can have a powder layer 5 with minimal variation in basis weight, achieved by directly coating the powder 3 with fluidity. Therefore, this method for manufacturing the powder layer 5 does not involve a process of dispersing the powder 3 in a solvent and then drying it, but rather involves directly coating the powder 3. This prevents material degradation due to solvents and suppresses cost increases. Furthermore, the uniform basis weight of the powder layer 5 improves the quality of the electrodes within the energy device, enabling the manufacture of high-quality energy devices at a low cost.

[0072] Furthermore, the powder layer 5 may be a compressed powder layer obtained by further rolling press processing.

[0073] [Powder layer] In one embodiment of the present disclosure, the powder layer 5 of the energy device has a film thickness of 30 μm or more formed on the current collector, which is a sheet 4. The powder layer 5 also contains powder composed of at least one type of particulate material. Furthermore, the concentration of the solvent contained in the powder layer 5 is 50 ppm or less, and the basis weight variation is small.

[0074] This results in a powder layer 5 with minimal variation in basis weight and suppressed degradation by solvents. Furthermore, since solvent drying is not required, energy consumption for drying the solvent can be reduced, thereby reducing the environmental impact and preventing increases in manufacturing costs. Therefore, by using such a powder layer 5 in energy devices, it is possible to improve the output and quality of energy devices, reduce the environmental impact, and lower costs.

[0075] The powder layer 5 of this embodiment can be used, for example, in an all-solid-state battery.

[0076] The details of powder layer 5 are described below.

[0077] The powder layer 5 is formed on the current collector, which is a sheet 4. The powder layer composite is the powder layer 5 of an energy device. For example, the powder layer composite may be used as an electrode in an energy device or in an all-solid-state battery. The current collector may further include other layers located between the current collector and the powder layer 5. These other layers may be, for example, a connecting layer made of a conductive carbon material.

[0078] The powder layer 5 has a thickness of 30 μm or more. There is no particular upper limit to the thickness of the powder layer 5, but for example, it should be 2000 μm or less.

[0079] Furthermore, the powder layer 5 includes powder 3 composed of at least one type of particle material.

[0080] The concentration of solvent in powder layer 5 is 50 ppm or less. In other words, powder layer 5 is substantially solvent-free. Here, "substantially solvent-free" means either completely free of solvent or unavoidably present at a concentration of 50 ppm or less as an impurity. The solvent concentration is measured by weight.

[0081] The size of the powder layer 5 in a plan view is, for example, 30 mm x 30 mm or larger. There is no particular upper limit to the size of the powder layer 5 in a plan view, but for example, it is 300 mm x 500 mm or smaller.

[0082] In any 30mm x 30mm area on the surface of the powder layer 5, the basis weight variation of the powder layer 5 is 8% or less.

[0083] The basis weight can be measured using the following method, for example: First, the powder layer 5 and the current collector are pressed together from above and below. Then, the powder layer 5 and the current collector are punched out into a circle with a diameter of 5 mm to 9 mm, and the total weight of the punched-out powder layer 5 and current collector is measured. The weight of the powder layer 5 is then calculated by subtracting the weight of the current collector from the same lot, which was previously measured and punched out with a diameter of 5 mm to 9 mm, from the total weight. The basis weight can then be calculated by dividing this weight by the area of ​​the circle with a diameter of 5 mm to 9 mm.

[0084] Furthermore, the variation in basis weight is measured, for example, by the following method. First, an arbitrary 30mm x 30mm area is selected on the surface of the powder layer 5 in a plan view. This area may be the central area of ​​the surface of the powder layer 5, or it may include the edges of the powder layer 5. Then, within this area, five or more circular holes are punched out, for example, with a diameter of 5mm or more and a diameter of 9mm or less, and the basis weight is measured using the method described above. Nine or more holes may be punched out to improve the accuracy of the variation measurement. The variation in basis weight is calculated by dividing the difference (specifically the absolute value of the difference) between the average basis weight of all punched-out holes and the basis weight of the hole with the largest difference from the average by the average. In other words, a basis weight variation of 8% or less means that at every punched-out hole, the difference from the average basis weight is 8% or less of the average.

[0085] The powder layer 5 is formed, as will be described in detail later, by, for example, applying high-frequency vibrations to the powder 3 supplied to the surface of the sheet 4, thereby imparting fluidity to the powder 3 and aligning the powder 3 in the powder layer 5. Since there is little variation in basis weight in the width direction, it is possible to manufacture high-quality powder layers 5 with a size of 30 mm x 30 mm or more and a thickness of 30 μm or more. For this reason, the powder layer 5 can be used in large, high-capacity energy devices.

[0086] Furthermore, the powder layer 5 is manufactured, for example, through a coating process that is substantially free of solvents. This allows for the formation of a powder layer 5 that is substantially free of solvents. As a result, the powder layer 5 is not damaged by solvents. Therefore, deterioration of the powder layer 5 is suppressed, and the variation in the basis weight of the powder 3 in the powder layer 5 is small, making it possible to form a powder layer 5 for large, high-capacity energy devices with high output and excellent quality.

[0087] Furthermore, the powder layer 5 can be used, for example, as the positive electrode, negative electrode, or solid electrolyte layer of an energy device such as an all-solid-state battery.

[0088] When the powder layer 5 is used as the positive electrode, for example, the sheet 4 is the positive electrode current collector, and the powder layer 5 containing the powder 3 is the positive electrode mixture layer. In other words, the positive electrode mixture layer is formed on the positive electrode current collector. The powder 3 in the positive electrode mixture layer includes, as at least one type of particulate material, a positive electrode active material and an ion-conductive solid electrolyte.

[0089] When the powder layer 5 is used as the negative electrode, for example, the sheet 4 is the negative electrode current collector, and the powder layer 5 containing the powder 3 is the negative electrode mixture layer. In other words, the negative electrode mixture layer is formed on the negative electrode current collector. The powder 3 in the negative electrode mixture layer includes at least one type of particulate material, namely a negative electrode active material and an ionic conductive solid electrolyte.

[0090] When the powder layer 5 is used as a solid electrolyte layer, for example, the powder layer 5 containing the powder 3 is a solid electrolyte layer. The solid electrolyte layer is formed on the surface of the powder layer 5 at the positive electrode or on the surface of the powder layer 5 at the negative electrode. The powder 3 in the solid electrolyte layer contains a solid electrolyte having ion conductivity as at least one type of particulate material.

[0091] The concentration of solvent in the positive electrode mixture layer, negative electrode mixture layer, and solid electrolyte layer is 50 ppm or less. In other words, the positive electrode mixture layer, negative electrode mixture layer, and solid electrolyte layer are substantially solvent-free. Here, "substantially solvent-free" means either that these layers contain no solvent at all, or that these layers inevitably contain 50 ppm or less of solvent as impurities.

[0092] The solvent is, for example, an organic solvent. The method for measuring the solvent is not particularly limited, and it can be measured using, for example, gas chromatography, the mass change method, or the like. Examples of organic solvents include nonpolar organic solvents such as heptane, xylene, and toluene, polar organic solvents such as tertiary amine solvents, ether solvents, thiol solvents, and ester solvents, and combinations thereof. Examples of tertiary amine solvents include triethylamine, tributylamine, and triamylamine. Examples of ether solvents include tetrahydrofuran and cyclopentyl methyl ether. Examples of thiol solvents include ethanethiol. Examples of ester solvents include butyl butyrate, ethyl acetate, and butyl acetate.

[0093] Next, details of the materials used for the positive electrode active material layer, negative electrode active material layer, and solid electrolyte layer will be described.

[0094] The positive electrode active material is a substance in which metal ions such as lithium (Li) are inserted into or removed from the crystal structure at a potential higher than that of the negative electrode, and oxidation or reduction occurs with the insertion or removal of metal ions such as lithium. The type of positive electrode active material is appropriately selected according to the type of all-solid-state battery, and examples include oxide active materials and sulfide active materials.

[0095] In this embodiment, an oxide active material (lithium-containing transition metal oxide) is used as the positive electrode active material. Examples of oxide active materials include LiCoO2, LiNiO2, LiMn2O4, LiCoPO4, LiNiPO4, LiFePO4, LiMnPO4, and compounds obtained by substituting one or two different elements for the transition metal of these compounds. Examples of compounds obtained by substituting one or two different elements for the transition metal of the above compounds include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.5 Mn 1.5Known materials such as O2 are used. The positive electrode active material may be used alone or in combination of two or more types.

[0096] Examples of the positive electrode active material's shape include particulate and thin film forms. When the positive electrode active material is particulate, its particle size may be, for example, in the range of 50 nm to 30 μm, or in the range of 1 μm to 15 μm. A particle size of 50 nm or more tends to improve handling. On the other hand, if the particle size is 30 μm or less, using a small-particle active material increases the surface area, making it easier to obtain a high-capacity positive electrode. In this specification, the particle size of the material contained in the positive electrode mixture layer or negative electrode mixture layer is, for example, the average particle size (D50) described above.

[0097] The content of the positive electrode active material in the positive electrode mixture layer is not particularly limited, but may be in the range of 40% by weight or more and 99% by weight or 70% by weight or more and 95% by weight or less.

[0098] The surface of the positive electrode active material may be covered with a coating layer. This is because it can suppress the reaction between the positive electrode active material (e.g., oxide active material) and the solid electrolyte (e.g., sulfide-based solid electrolyte). Examples of materials for the coating layer include Li-ion conductive oxides such as LiNbO3, Li3PO4, and LiPON. The average thickness of the coating layer is, for example, in the range of 1 nm to 20 nm, or in the range of 1 nm to 10 nm.

[0099] The ratio of positive electrode active material to solid electrolyte in the positive electrode mixture layer may be within the range of 1 to 19, or 2.3 to 19, when calculated by weight as positive electrode active material / solid electrolyte = weight ratio. This weight ratio range ensures that both lithium ion conduction pathways and electron conduction pathways are readily available within the positive electrode mixture layer.

[0100] The negative electrode active material is a substance in which metal ions such as lithium are inserted into or removed from its crystal structure at a lower potential than that of the positive electrode, and oxidation or reduction occurs in conjunction with the insertion or removal of these metal ions.

[0101] In this embodiment, the negative electrode active material may be, for example, easily alloyable metals with lithium such as lithium, indium, tin, and silicon, carbon materials such as hard carbon and graphite, and Li4Ti5O 12 SiO x Known materials such as oxide active materials can be used. Furthermore, composite materials obtained by appropriately mixing the above-mentioned negative electrode active materials may also be used as the negative electrode active material.

[0102] The particle size of the negative electrode active material is, for example, 30 μm or less. By using an active material with a small particle size, the surface area is increased, allowing for a higher capacity.

[0103] The ratio of negative electrode active material to solid electrolyte contained in the negative electrode mixture layer, when calculated by weight as negative electrode active material / solid electrolyte = weight ratio, may be, for example, in the range of 0.6 to 19, or in the range of 1 to 5.7. This weight ratio range ensures that both lithium ion conduction pathways and electron conduction pathways are readily available within the negative electrode mixture layer.

[0104] Solid electrolytes can be appropriately selected depending on the conductive ion species (e.g., lithium ions), and can be broadly divided into sulfide-based solid electrolytes, oxide-based solid electrolytes, and halide-based solid electrolytes.

[0105] The type of sulfide-based solid electrolyte in this embodiment is not particularly limited, but examples of sulfide-based solid electrolytes include Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, and Li2S-P2S5. In particular, from the viewpoint of excellent lithium ion conductivity, the sulfide-based solid electrolyte may contain Li, P, and S. The sulfide-based solid electrolyte may be used alone or in combination of two or more types. Furthermore, the sulfide-based solid electrolyte may be crystalline, amorphous, or glass ceramic. Note that the above description of "Li2S-P2S5" means a sulfide-based solid electrolyte using a raw material composition containing Li2S and P2S5, and the same applies to other descriptions.

[0106] In this embodiment, one form of the sulfide-based solid electrolyte is a sulfide glass ceramic containing Li2S and P2S5. The ratio of Li2S to P2S5, when calculated in moles with Li2S / P2S5 = molar ratio, is, for example, in the range of 2.3 to 4, or in the range of 3 to 4. This molar ratio range allows for a crystal structure with high ion conductivity while maintaining a lithium concentration that affects battery characteristics.

[0107] In this embodiment, the shape of the sulfide-based solid electrolyte can be, for example, a perfect sphere, an ellipsoid, or other particle shape, or a thin film shape. When the sulfide-based solid electrolyte material is in the form of particles, the particle size of the sulfide-based solid electrolyte is not particularly limited, but it may be 30 μm or less, 20 μm or less, or 10 μm or less, as this makes it easier to improve the packing efficiency in the positive or negative electrode. On the other hand, the particle size of the sulfide-based solid electrolyte may be 0.001 μm or more, or 0.01 μm or more.

[0108] Next, the oxide-based solid electrolyte in this embodiment will be described. The type of oxide-based solid electrolyte is not particularly limited, but LiPON, Li3PO4, Li2SiO2, Li2SiO4, Li 0.5 La0.5 TiO3, Li 1.3 Al 0.3 Ti 0.7 (PO4)3, La 0.51 Li 0.34 TiO 0.74 Li 1.5 Al 0.5 Ge 1.5 Examples include (PO4)3. The oxide-based solid electrolyte may be used individually or in combination of two or more types.

[0109] Next, we will describe the details of the positive electrode current collector and the negative electrode current collector.

[0110] The positive electrode in this embodiment includes a positive electrode current collector made of, for example, a metal foil. The positive electrode current collector can be a foil-like body, plate-like body, mesh-like body, etc., made of, for example, aluminum, gold, platinum, zinc, copper, SUS, nickel, tin, titanium, or an alloy of two or more of these.

[0111] Furthermore, the thickness and shape of the positive electrode current collector may be appropriately selected depending on the application of the positive electrode.

[0112] The negative electrode in this embodiment includes a negative electrode current collector made of, for example, metal foil. The negative electrode current collector can be made of, for example, SUS, gold, platinum, zinc, copper, nickel, titanium, tin, or an alloy of two or more of these materials, in the form of foil, plate, mesh, etc.

[0113] Furthermore, the thickness and shape of the negative electrode current collector may be appropriately selected depending on the application of the negative electrode.

[0114] Furthermore, the powder layer 5 may be a compressed powder layer obtained by pressing the powder layer 5.

[0115] (Examples) The present disclosure will be described in detail below with reference to the following embodiments. However, the present disclosure is not limited to the following embodiments.

[0116] In Examples 1 and 2 and Comparative Example 1, the squeegee was cylindrical in shape, and simulations were performed at a vibration frequency of 2.5 kHz to analyze the variation in basis weight of the powder layer 5 after passing through the squeegee.

[0117] The results are shown in Table 1 below.

[0118] In Example 1, the second-stage squeegee 12 is positioned on the side of the direction of travel that is closer to the first-stage squeegee 11, and the first-stage squeegee 11 and the second-stage squeegee 12 are positioned offset along the powder layer width direction by a quarter wavelength of their natural vibration.

[0119] In Example 2, the configuration of Example 1 was used, but the second-stage squeegee 12 was further vibrated so that the amplitude of the second-stage squeegee 12 was half the amplitude of the first-stage squeegee 11.

[0120] Comparative Example 1 used only the first-stage squeegee 11. Here, the basis weight variation in Table 1 refers to the standard deviation of the basis weight distribution in the powder layer width direction, normalized to the value of Comparative Example 1. Furthermore, the amplitude was normalized with the amplitude of the first-stage squeegee 11 set to 1.

[0121] In Example 1, by positioning the second-stage squeegee 12 with a shift of one-quarter of the natural vibration wavelength relative to the first-stage squeegee 11, stable coating with less variation in basis weight becomes possible. Furthermore, in Example 2, by making the amplitude of the second-stage squeegee 12 half that of the first-stage squeegee 11, even more stable coating with less variation in basis weight becomes possible.

[0122] [Table 1]

[0123] (Other variations) The powder coating apparatus relating to this disclosure has been described above based on embodiments, but this disclosure is not limited to the above embodiments.

[0124] Furthermore, this disclosure also includes forms that can be obtained by applying various modifications to the above embodiments that a person skilled in the art could conceive, and forms that can be realized by arbitrarily combining the components and functions of the above embodiments without departing from the spirit of this disclosure.

[0125] According to the powder coating apparatus of this disclosure, it is possible to form a high-performance and environmentally friendly powder layer that reduces variations in basis weight caused by an uneven structure in which the surface of the powder layer is eroded in a sinusoidal standing wave pattern. [Industrial applicability]

[0126] The powder coating apparatus of this disclosure can form a uniform powder layer with minimal variation in film thickness without using solvents, making it applicable to applications such as the composite layer of high-quality all-solid-state batteries. [Explanation of Symbols]

[0127] 1. Powder coating apparatus 3 Powder 4 sheets 5 Powder layer h1 Gap between the first squeegee and the sheet h2 2nd stage squeegee and gap between the sheet 11. First squeegee (first squeegee) 12. Second squeegee (second squeegee) 13. Third squeegee (third squeegee) 14. Fourth squeegee (the fourth squeegee)

Claims

1. A drive device for moving a component in a predetermined direction, A powder supply device that supplies powder to the surface of the aforementioned member, The system includes a first squeegee and a second squeegee, which are arranged to form a gap between the member and the member, and which adjust the thickness of the powder supplied to the surface of the member by the powder supply device, The first squeegee and the second squeegee vibrate naturally at frequencies between 2 kHz and 300 kHz. The first squeegee is located on the powder supply side of the second squeegee, The second squeegee is offset from the first squeegee by a quarter wavelength of the natural vibration along the width direction of the powder supplied to the surface of the member. Powder coating equipment.

2. The amplitude of the first squeegee is greater than or equal to the amplitude of the second squeegee. The powder coating apparatus according to claim 1.

3. The distance between the second squeegee and the member is greater than or equal to the distance between the first squeegee and the member. The powder coating apparatus according to claim 1 or 2.

4. Furthermore, the second squeegee is provided with a third squeegee positioned on the opposite side from the first squeegee, The third squeegee is positioned relative to the second squeegee, offset by one-eighth of a wavelength of the natural vibration along the width direction of the powder supplied to the surface of the member. A powder coating apparatus according to any one of claims 1 to 3.

5. Furthermore, the third squeegee is provided with a fourth squeegee positioned on the opposite side from the second squeegee, The fourth squeegee is positioned relative to the second squeegee, offset by one-eighth of the wavelength of the natural vibration along the width direction of the powder supplied to the surface of the member, such that the third squeegee is positioned offset from the second squeegee by one-eighth of the wavelength of the natural vibration in the opposite direction to the direction in which the third squeegee is positioned offset from the second squeegee by one-eighth of the wavelength of the natural vibration. The powder coating apparatus according to claim 4.

6. The aforementioned powder has an average particle size (D50) of 0.005 μm or more and 30 μm or less. A powder coating apparatus according to any one of claims 1 to 5.

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