Laser drying device

Abstract

The present disclosure aims to provide a laser drying apparatus that can efficiently dry an electrode composite layer even when multiple laser-transparent protective plates are arranged side by side in the planar direction to form a large-area laser-transparent protective plate. [Solution] A laser drying apparatus 100 for drying an electrode composite layer, comprising: the laser drying apparatus 100, a furnace body 110, a first laser light source 120-1, and a second laser light source 120-2, wherein the furnace body 110 comprises a first laser-transparent protective plate 112-1 and a second laser-transparent protective plate 112-2, the first laser-transparent protective plate 112-1 and the second laser-transparent protective plate 112-2 are arranged side by side in the planar direction, the first laser light source 120-1 irradiates the electrode composite layer in the furnace body 110 with laser light 200 via the first laser-transparent protective plate 112-1, and the second laser light source 120-2 irradiates the electrode composite layer in the furnace body 110 with laser light 200 via the second laser-transparent protective plate 112-2.

Description

[Technical Field]

[0001] This disclosure relates to a laser drying apparatus. [Background technology]

[0002] Laser drying is a known method for drying electrode composite layers coated on current collector layers. Compared to hot air drying, laser drying consumes less energy and has a lower environmental impact. Various proposals have been made to improve the drying efficiency and quality of laser drying.

[0003] Patent Document 1 discloses a method for manufacturing an electrode sheet, comprising: a coating step of applying an active material paste to the surface of a long metal sheet while conveying the metal sheet; and a drying step performed in parallel with the coating step, in which the active material paste on the metal sheet is dried while the metal sheet with the active material paste applied is conveyed inside a furnace, wherein hot air is blown inside the furnace along the conveying direction of the metal sheet, and light is irradiated onto the active material paste on the metal sheet from at least one light source, and the temperature of the active material paste becomes higher than the temperature inside the furnace as a result of the light irradiation. Patent Document 1 states that, according to the disclosure in Patent Document 1, the temperature of the active material paste can be appropriately controlled and the drying of the active material paste can be performed uniformly in a short time.

[0004] Patent Document 2 discloses a method for manufacturing an electrode, comprising: a coating step of applying an active material mixture containing an active material, a solvent, a conductive material, and a binder to pre-set mixture application locations on a long metal foil being transported to form a coated area of ​​the active material mixture; a first irradiation step performed before the coating step, in which a laser is irradiated onto an irradiation position on the long metal foil located upstream in the transport direction of the long metal foil from both ends of the mixture application locations along the short direction of the long metal foil; a second irradiation step performed after the first irradiation step, in which a laser is irradiated onto both edges in the short direction of the coated area formed by the coating step; and a drying step performed after the second irradiation step, in which the coated area is dried. Patent Document 2 states that, according to the disclosure in Patent Document 2, it is possible to provide a method for manufacturing an electrode that can suppress sagging of the edges of the coated area and detachment of the conductive material from the edges.

[0005] Patent Document 3 discloses an electrode drying method that includes a constant-rate drying step in which an electrode substrate coated with an electrode slurry is dried while moving at an inclined angle with respect to a horizontal plane, and a decrease-rate drying step in which the electrode substrate is dried while moving horizontally. Patent Document 3 states that, according to the disclosure in Patent Document 3, it is possible to suppress the lifting phenomenon of binder components during the drying process for the electrode and to improve the adhesion between the electrode mixture layer and the electrode current collector. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2024-39889 [Patent Document 2] Japanese Patent Publication No. 2019-29256 [Patent Document 3] Special Publication No. 2023-504346 [Overview of the project] [Problems that the invention aims to solve]

[0007] When the furnace body is provided with a laser-transmissive protective plate and laser light is irradiated from a laser light source outside the furnace body through the laser-transmissive protective plate onto the electrode composite layer inside the furnace body, there is no need to dispose the laser light source inside the high-temperature furnace body, and the laser light source and the furnace body can be thermally insulated from each other.

[0008] Also, when the furnace body is provided with a laser-transmissive protective plate in this way, by reducing the distance between the laser-transmissive protective plate and the electrode composite layer, the size of the furnace body can be reduced and the drying efficiency can be increased. On the other hand, in this case, the distance between the laser-transmissive protective plate and the laser light source becomes longer and the irradiation area of the laser light on the laser-transmissive protective plate becomes larger, so it is necessary to prepare a large-area laser-transmissive protective plate.

[0009] However, it is difficult to prepare a large-area single plate of a laser-transmissive protective plate made of quartz glass or the like. In contrast, it is conceivable to juxtapose a plurality of laser-transmissive protective plates in the plane direction. However, since the transmittance of the laser is low at the boundary between the plurality of laser-transmissive protective plates, the desired drying efficiency and / or drying uniformity of the electrode composite layer may not be obtained.

[0010] Therefore, an object of the present disclosure is to provide a laser drying apparatus that can efficiently dry an electrode composite layer even when a large-area laser-transmissive protective plate is formed by juxtaposing a plurality of laser-transmissive protective plates in the plane direction.

Means for Solving the Problems

[0011] The present disclosure achieves the above object by the following means. 〈Aspect 1〉 A laser drying apparatus for drying an electrode composite layer, The laser drying apparatus includes a furnace body, a first laser light source, and a second laser light source, The furnace body includes a first laser-transmissive protective plate and a second laser-transmissive protective plate, The first laser-transmissive protective plate and the second laser-transmissive protective plate are juxtaposed in the plane direction, The first laser light source irradiates the electrode composite layer inside the furnace body with laser light through the first laser-transparent protective plate. The second laser light source irradiates the electrode composite layer inside the furnace body with laser light via the second laser-transparent protective plate, and The first and second laser light sources described above do not irradiate the boundary portion of the first and second laser-transparent protective plates with laser light. Laser drying device. <Aspect 2> The apparatus according to embodiment 1, wherein the first and second laser light sources are formed by branching laser light from a single parent laser light source. <Aspect 3> The apparatus according to embodiment 2, wherein the laser light from the above-mentioned parent laser light source is branched by a fiber or prism. <Aspect 4> The above laser drying apparatus further comprises a third laser light source, The above furnace body further comprises a third laser-transparent protective plate, The above-mentioned third laser light source irradiates the above-mentioned electrode composite layer with a laser through the above-mentioned third laser-transparent protective plate, and The first to third laser light sources described above do not irradiate the boundary portion of the first to third laser-transparent protective plates described above with laser light. The apparatus described in aspects 1 to 3. <Aspect 5> A method for manufacturing an electrode laminate using the apparatus described in aspects 1 to 3, The first laser light source is irradiated onto the electrode composite layer coated on the current collector layer through the first laser-transparent protective plate, and The laser light is irradiated from the second laser light source through the second laser-transparent protective plate onto the electrode composite layer coated on the current collector layer. A method for manufacturing an electrode stack, including [the specified element]. [Effects of the Invention]

[0012] According to this disclosure, a laser drying apparatus can be provided that can efficiently dry an electrode composite layer even when multiple protective plate pieces are arranged side by side in the planar direction to form a large-area protective plate. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic diagram illustrating the laser drying apparatus of this disclosure. [Figure 2] Figure 2 is a schematic diagram illustrating the laser drying apparatus of this disclosure. [Figure 3] Figure 3 is a schematic diagram illustrating the laser drying apparatus of this disclosure. [Modes for carrying out the invention]

[0014] The embodiments of this disclosure will be described in detail below. However, this disclosure is not limited to the embodiments described below and can be implemented in various ways within the scope of the gist of this disclosure.

[0015] Laser drying equipment A laser drying apparatus for drying an electrode composite layer, The above laser drying apparatus comprises a furnace body, a first laser light source, and a second laser light source. The above furnace body comprises a first laser-transparent protective plate and a second laser-transparent protective plate. The first laser-transparent protective plate and the second laser-transparent protective plate are arranged side by side in the planar direction. The first laser light source irradiates the electrode composite layer inside the furnace body with laser light through the first laser-transparent protective plate. The second laser light source irradiates the electrode composite layer inside the furnace body with laser light via the second laser-transparent protective plate, and The first and second laser light sources described above do not irradiate the boundary portion of the first and second laser-transparent protective plates with laser light. Laser drying device.

[0016] According to this disclosure, a laser drying apparatus can be provided that can efficiently dry an electrode composite layer even when multiple protective plate pieces are arranged side by side in the planar direction to form a large-area protective plate.

[0017] The Disclosers considered, when laser drying an electrode composite layer, placing a laser-transparent protective plate in the furnace body to insulate the laser light source from the inside of the furnace body, so that the laser light from the laser light source is irradiated onto the electrode composite layer through the laser-transparent protective plate, and reducing the distance between the laser-transparent protective plate and the electrode composite layer to improve drying efficiency. When a large-area laser-transparent protective plate with multiple laser-transparent protective plates placed side by side was used to reduce the distance between the laser-transparent protective plate and the electrode composite layer, the laser transmittance was low at the boundaries between the multiple laser-transparent protective plates, and the desired drying efficiency of the electrode composite layer could not be obtained.

[0018] In contrast, the Disclosers have found that when the multiple laser-transparent protective plates constituting the large-area laser-transparent protective plate are composed of a first laser-transparent protective plate and a second laser-transparent protective plate, the electrode composite layer can be dried with high efficiency by providing a first laser light source and a second laser light source in the laser drying apparatus. The first laser light source irradiates the electrode composite layer inside the furnace body with laser light through the first laser-transparent protective plate, and the second laser light source irradiates the electrode composite layer inside the furnace body with laser light through the second laser-transparent protective plate. Therefore, the boundary between the first and second laser-transparent protective plates is not irradiated with laser light. Consequently, there is no attenuation of the laser light irradiation energy to the electrode composite layer, and the drying efficiency of the electrode composite layer can be increased.

[0019] Specifically, as shown in Figure 1, the laser drying apparatus 100 comprises a furnace body 110, a first laser light source 120-1, and a second laser light source 120-2.

[0020] The laser drying apparatus 100 has a conveying device 130, and the conveying roller 132 rotates, allowing the electrode mixture layer placed on the conveying belt 131 to be moved at a constant speed in the conveying direction. Therefore, it is possible to transport the electrode mixture layer from outside the furnace body 110 into the furnace body 110 and to transport the electrode mixture layer from inside the furnace body 110 to outside the furnace body 110.

[0021] The furnace body 110 is composed of an outer substrate 111, a first laser-transparent protective plate 112-1, and a second laser-transparent protective plate 112-2. The electrode composite layer, which has been transported into the furnace body 110 by the transport equipment 130, is irradiated with laser light 200 from a first laser light source 120-1 located outside the furnace body 110 via the first laser-transparent protective plate 112-1, and similarly, the electrode composite layer is irradiated with laser light 200 from a second laser light source 120-2 located outside the furnace body 110 via the second laser-transparent protective plate 112-2. Here, the boundary between the first laser-transparent protective plate 112-1 and the second laser-transparent protective plate 112-2 is not irradiated with laser light.

[0022] Furthermore, the laser drying apparatus 100 has a hot air supply device 140, which consists of a hot air generator 141, an air supply duct 142, and an air supply nozzle 143. The hot air supply device 140 supplies hot air generated by the hot air generator 141 into the furnace body 110 via the air supply duct 142 and the air supply nozzle 143. Steam near the surface of the electrode mixture layer generated by laser irradiation is removed by the hot air and then discharged to the outside of the furnace body 110 by the exhaust device 150. This makes it possible to increase the drying efficiency of the electrode mixture layer.

[0023] Although the inside of the furnace body 110 is hot due to the hot air mentioned above, the first laser-transparent protective plate 112-1 and the second laser-transparent protective plate 112-2 are present between the first laser light source 120-1 and the second laser light source 120-2 and the inside of the furnace body 110, so the first laser light source 120-1 and the second laser light source 120-2 are protected from heat transfer from inside the furnace body 110.

[0024] The laser drying apparatus of this disclosure is a laser drying apparatus for drying an electrode composite layer.

[0025] In this disclosure, "electrode mixture" means a composition that can constitute an electrode active material layer, either as is or by further containing other components. And "electrode mixture layer" means a layer that, in addition to the "electrode mixture," contains a dispersion medium and can be applied and dried to form an electrode active material layer.

[0026] The laser drying apparatus of this disclosure comprises a furnace body, a first laser light source, and a second laser light source. The laser drying apparatus may further have a third laser light source, as shown in Figure 3(a). Optionally, the laser drying apparatus may also have a fourth laser light source, a fifth laser light source, and a sixth laser light source. Furthermore, the laser drying apparatus may further include a conveying device, a hot air supply device, and an exhaust device.

[0027] When x is the distance between the first or second laser light source and the electrode composite layer, and y is the distance between the laser-transparent protective plate and the electrode composite layer, the following conditions may be met: y / x ≤ 0.15, 0.14, 0.13, 0.12, 0.10, 0.08, or 0.05. Satisfying these conditions increases the drying efficiency of the electrode composite layer. Alternatively, the following conditions may be met: y / x ≥ 0.01, 0.02, 0.03, or 0.04.

[0028] Specifically, for example, as shown in Figure 2, the electrode composite layer 300 is placed on a conveyor belt 131 and irradiated with laser light. The above x is the shortest distance in the height direction from the laser light irradiation part of the first laser light source 120-1 or the second laser light source 120-2 to the electrode composite layer 300. Also, the above y is the shortest distance in the height direction from the first laser-transparent protective plate 112-1 or the second laser-transparent protective plate 112-2 to the electrode composite layer 300.

[0029] The distance x between the first or second laser light source and the electrode composite layer is not particularly limited and may be determined appropriately considering the irradiation area of ​​the laser light, etc. The distance x may be, for example, 300 mm or more, 500 mm or more, 1000 mm or more, 1500 mm or more, 2000 mm or more, or 5000 mm or less, 4000 mm or less, or 3000 mm or less.

[0030] The distance y between the first or second laser-transparent protective plate and the electrode composite layer is not particularly limited and may be appropriately determined considering y / x, the thickness of the electrode composite layer, etc. The distance y may be, for example, 5 mm or more, 10 mm or more, 30 mm or more, 50 mm or more, or 100 mm or more, and may also be 750 mm or less, 500 mm or less, 400 mm or less, or 300 mm or less.

[0031] <Furnace body> The furnace body comprises a first laser-transparent protective plate and a second laser-transparent protective plate. As shown in Figure 1, the furnace body has an outer substrate 111, a first laser-transparent protective plate 112-1, and a second laser-transparent protective plate 112-2. At least a part of the outer casing of the furnace body may be the first and / or second laser-transparent protective plate. The position of the first laser-transparent protective plate may be such that laser light generated from the first laser light source can be irradiated onto the electrode composite layer without leakage through the first laser-transparent protective plate, and the position of the second laser-transparent protective plate may be such that laser light generated from the second laser light source can be irradiated onto the electrode composite layer without leakage through the second laser-transparent protective plate. As shown in Figure 3(a), if a third laser light source is used, the furnace body may further have a third laser-transparent protective plate that transmits laser light from the third laser light source. Similarly, when using a fourth laser light source, a fifth laser light source, and a sixth laser light source, the system may further include a fourth laser-transparent protective plate, a fifth laser-transparent protective plate, and a sixth laser-transparent protective plate that transmit laser light from those laser light sources.

[0032] The material of the outer substrate is not particularly limited and may be, for example, steel, stainless steel, aluminum, etc. The outer substrate may be surface-treated such as zinc plating or powder coating. The size of the furnace body is not particularly limited and may be determined as appropriate considering the dimensions of the electrode composite layer, etc.

[0033] The dimensions of the furnace body are not particularly limited and may be determined as appropriate, taking into consideration the dimensions of the electrode mixture layer, etc. The furnace body may also have openings for loading and unloading the electrode mixture layer using conveying equipment.

[0034] From the viewpoint of improving the drying efficiency of the electrode mixture layer, the furnace body preferably has high thermal insulation properties, and may have thermal insulation material on the outside of the outer substrate. Examples of thermal insulation materials include firebrick, ceramic fiber, and glass wool.

[0035] (Laser-transparent protective plate) The first laser-transparent protective plate and the second laser-transparent protective plate are arranged side by side in the planar direction. The "planar direction" of the protective plate means the direction parallel to the main surface (largest surface) of the protective plate. Specifically, for example, in Figure 1, it is any direction perpendicular to the height direction of the furnace body, and may also be the transport direction, or a direction perpendicular to both the height direction and the transport direction (width direction).

[0036] The first laser-transparent protective plate and the second laser-transparent protective plate may be placed side by side with a joint in between.

[0037] The material of the joint is not particularly limited, but it is preferably a material with low thermal conductivity and a soft texture. The joint material may be selected from, for example, fluorine-based gels, silicon-based gels, acrylic-based gels, and combinations thereof.

[0038] The thermal conductivity of the joint material is not particularly limited and may be 1.40 W / (m·K) or less, 1.20 W / (m·K) or less, 1.00 W / (m·K) or less, 0.80 W / (m·K) or less, 0.70 W / (m·K) or less, 0.60 W / (m·K) or less, or 0.50 W / (m·K) or less, or 0.10 W / (m·K) or more, 0.30 W / (m·K) or more, or 0.50 W / (m·K) or more. Due to the low thermal conductivity, the first and second laser light sources are protected from the temperature inside the furnace body. The thermal conductivity can be measured by the heat flow meter method according to ASTEM-E-1530.

[0039] The heat resistance temperature of the joint material is not particularly limited and may be determined as appropriate, taking into consideration the temperature inside the furnace body. The above temperature may be, for example, 50°C or higher, 100°C or higher, 130°C or higher, 150°C or higher, 160°C or higher, 180°C or higher, 200°C or higher, 220°C or higher, 240°C or higher, 260°C or higher, 280°C or higher, or 300°C or higher, and may also be 500°C or lower, 450°C or lower, 400°C or lower, or 350°C or lower.

[0040] The hardness of the gel material is not particularly limited; for example, the Shore A hardness may be 0 or higher, 1 or higher, 3 or higher, 5 or higher, 7 or higher, or 10 or higher, or it may be 30 or lower, 25 or lower, or 20 or lower. The softness of the gel material helps to suppress damage to the first and second laser-transparent protective plates due to thermal expansion of the first and second laser-transparent protective plates. The hardness (Shore A) of the gel material can be measured in accordance with JIS-K-6253.

[0041] Fluorine-based gels are gels containing fluorine compounds, and commercially available coating agents for optical applications can be used, for example, Novec Fluorochemical Gel (manufactured by 3M).

[0042] Silicone-based gels are gels containing silicon compounds, and commercially available coating agents for optical applications can be used. Silicone-based gels may be, for example, silicone gels, such as Sylgard 527 (manufactured by Dow Chemical).

[0043] Acrylic gels are gels containing acrylic resin, and commercially available coating agents for optical applications can be used. For example, the acrylic gel may be Cyrilite (manufactured by Rohm).

[0044] The laser light transmittance of the first and second laser-transparent protective plates may be 95.0% or higher, 96.0% or higher, 97.0% or higher, 98.0% or higher, 99.0% or higher, 99.5% or higher, or 99.8% or higher for laser light irradiated from the first and second laser light sources, and may be 100.0% or lower or 99.9% or lower. High laser light transmittance allows the light energy generated from the laser light source to be supplied to the electrode composite layer without waste.

[0045] The transmittance of laser light is the transmittance at the wavelength of the laser light if the laser light has a single wavelength, and the transmittance at the wavelength with the highest intensity if the laser light has multiple wavelengths. The transmittance of laser light can be measured by spectrophotometry using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu Corporation, SolidSpec-3700DUV).

[0046] The material of the first and second laser-transparent protective plates may be glass. The glass may be, for example, quartz glass, soda-lime glass, lead glass, borosilicate glass, alkali glass, etc.

[0047] The first and second laser-transparent protective plates may be double-glazed. Double-glazed glass improves thermal insulation performance. Double-glazed glass may have air, argon gas, krypton gas, etc., sealed between multiple panes of glass.

[0048] The thickness of the first and second laser-transparent protective plates is not particularly limited and may be appropriately determined depending on the material of the first and second laser-transparent protective plates. The thickness of the first and second laser-transparent protective plates may be, for example, 1 mm or more, 3 mm or more, 5 mm or more, 7 mm or more, or 10 mm or more, and may be 30 mm or less, 25 mm or less, 20 mm or less, or 15 mm or less.

[0049] The dimensions of the first and second laser-transparent protective plates are not particularly limited and may be such that the laser light generated from the first and second laser light sources passes into the furnace body without leakage.

[0050] The thermal conductivities of the first and second laser-transmissive protective plates are not particularly limited, and may be 1.50 W / (M·K) or less, 1.40 W / (M·K) or less, 1.38 W / (M·K) or less, 1.35 W / (M·K) or less, 1.30 W / (M·K) or less, 1.20 W / (M·K) or less, 1.10 W / (M·K) or less, or 1.00 W / (M·K) or less, and may also be 0.10 W / (M·K) or more, 0.30 W / (M·K) or more, or 0.50 W / (M·K) or more. Due to the small thermal conductivity, the first and second laser light sources are less affected by the temperature inside the furnace body. The thermal conductivity can be measured by the heat flow meter method in accordance with ASTEM-E-1530.

[0051] 〈Laser light source〉 The first laser light source irradiates laser light onto the electrode composite layer inside the furnace body through the first laser-transmissive protective plate, and the second laser light source irradiates laser light onto the electrode composite layer inside the furnace body through the second laser-transmissive protective plate.

[0052] The energy density of the laser light irradiated from the first and second laser light sources onto the electrode composite layer in the drying furnace is not particularly limited. For example, it may be 0.1 W / cm 2 or more, 0.5 W / cm<s 2 or more, 1.0 W / cm 2 or more, 2.0 W / cm 2 or more, or 3.0 W / cm 2 or more, and may also be 20.0 W / cm 2 or less, 10.0 W / cm 2 or less, 7.0 W / cm 2 or less, or 4.0 W / cm 2 or less. 2 以下、10.0W / cm 2 以下、7.0W / cm 2 以下、又は<<4.0W / cm>> 2 以下、であってもよい。

[0053] The irradiation area of the laser light irradiated from the first laser light source onto the electrode composite layer in the drying furnace and the irradiation area of the laser light irradiated from the second laser light source onto the electrode composite layer in the drying furnace may partially overlap or may have a gap.

[0054] The first and second laser light sources do not irradiate the boundary between the first and second laser-transparent protective plates with laser light. Because the laser light transmittance at the boundary between the first and second laser-transparent protective plates is low, avoiding irradiation of the boundary with laser light increases the energy density of the laser light irradiated onto the electrode composite layer.

[0055] If the laser drying apparatus has a third laser light source and the furnace body has a third laser-transparent protective plate, the third laser light source may irradiate the electrode composite layer with the laser through the third laser-transparent protective plate, and the third laser light source does not need to irradiate the boundary between the first to third laser-transparent protective plates with laser light.

[0056] The first and second laser light sources are located outside the furnace body. When the inside of the furnace body is at a high temperature, the first and second laser light sources can be protected from high heat by being located outside the furnace body. The first laser light source may be positioned so that the laser light is irradiated onto the first laser-transparent protective plate without any leakage, and the second laser light source may be positioned so that the laser light is irradiated onto the second laser-transparent protective plate without any leakage.

[0057] The first laser light source and the second laser light source may be arranged side by side in the planar direction. Furthermore, the distance between the first laser light source and the second laser light source is not particularly limited and may be appropriately determined considering the positions of the first and second laser-transparent protective plates, the irradiation area of ​​the laser light onto the electrode composite layer, etc.

[0058] The types of the first and second laser light sources are not particularly limited and may include, for example, a Yb fiber laser, a YAG laser, a carbon dioxide laser, etc. The wavelength of the laser light may be 0.5 μm or more, 0.6 μm or more, 0.7 μm or more, 0.8 μm or more, or 0.9 μm or more, and may be 1.5 μm or less, 1.4 μm or less, 1.3 μm or less, 1.2 μm or less, or 1.1 μm or less. The laser light may be a single wavelength or multiple wavelengths.

[0059] The outputs of the first and second laser light sources are not particularly limited and may be appropriately determined based on the laser light irradiation area, the available irradiation time, etc. The outputs of the first and second laser light sources may be, for example, 0.1 kW or more, 1 kW or more, 5 kW or more, 10 kW or more, 15 kW or more, 20 kW or more, or 30 kW or more, and may be 100 kW or less, 70 kW or less, or 50 kW or less.

[0060] The first and second laser light sources may be constructed by branching the laser light from a single parent laser light source. Specifically, for example, as shown in Figure 3(b), the laser light from the parent laser light source 121 may be branched by a fiber 122, or by a prism, a diffractive optical element (DOE), etc.

[0061] The shape of the irradiation area of ​​the electrode composite layer by the laser light from the first and second laser light sources may be, for example, rectangular. Furthermore, the size of the irradiation area is not particularly limited and may be appropriately determined by the dimensions of the electrode composite layer.

[0062] <Conveying equipment> The conveying equipment is not particularly limited and may be, for example, a roller conveyor, a belt conveyor, etc. The electrode mixture layer may be placed, for example, on a conveying path and transported into the furnace body and transported out of the furnace body.

[0063] The electrode mixture layer may be irradiated with laser light while being transported inside the furnace body by transport equipment. In this case, the transport speed may be appropriately determined considering the output of the first and second laser light sources, the amount of energy required to dry the electrode mixture layer, etc. The transport speed may be, for example, 0.1 m / s or more, 0.3 m / s or more, 0.5 m / s or more, or 1.0 m / s or more, or 3.0 m / s or less, 2.5 m / s or less, or 2.0 m / s or less.

[0064] The conveying equipment may be connected to other devices such as an electrode composite layer coating device or an electrode laminate winding device.

[0065] <Hot air supply equipment> The hot air supply equipment supplies hot air into the furnace body. By supplying hot air to the electrode mixture layer, steam on the surface of the electrode mixture layer can be removed, thereby improving drying efficiency.

[0066] The temperature of the hot air supplied from the hot air supply equipment may be 50°C or higher, 100°C or higher, 130°C or higher, 150°C or higher, 160°C or higher, 180°C or higher, 200°C or higher, 220°C or higher, 240°C or higher, 260°C or higher, 280°C or higher, or 300°C or higher, and may be 500°C or lower, 450°C or lower, 400°C or lower, or 350°C or lower.

[0067] The hot air supply equipment is not particularly limited and may, for example, supply air heated by gas combustion, oil combustion, electric heating, etc., to the electrode mixture layer via a blower fan through a blower duct and blower nozzle. From the viewpoint of drying the electrode mixture layer, the hot air is preferably low in humidity.

[0068] The direction of hot air supply is not particularly limited; for example, if the electrode mixture layer is transported inside the furnace body, the direction may be opposite to the transport direction. Furthermore, multiple air nozzles may be arranged, each with a different supply direction.

[0069] The wind speed of the hot air is not particularly limited and may be, for example, 5 m / s or more, 10 m / s or more, 15 m / s or more, or 20 m / s or more. Higher wind speeds result in higher drying efficiency of the electrode mixture layer. Alternatively, the wind speed of the hot air may be 60 m / s or less, 50 m / s or less, 40 m / s or less, or 30 m / s or less.

[0070] <Exhaust equipment> The inclusion of an exhaust system in the laser drying apparatus allows for the recovery of steam generated from the electrode mixture layer, thereby increasing drying efficiency. This steam can be water vapor or other gases.

[0071] The exhaust equipment may be configured, for example, by using an exhaust fan to draw steam in from the exhaust port and discharge it to the outside of the furnace body via an exhaust duct. The output of the exhaust fan, the dimensions of the exhaust port and exhaust duct may be determined appropriately considering the amount of steam generated, the internal pressure of the furnace body, etc.

[0072] From the viewpoint of improving drying efficiency, it is preferable that the exhaust port be located above the electrode mixture layer and in a position that does not interfere with laser irradiation. The distance between the exhaust port and the electrode mixture layer may be a distance sufficient to allow steam to be drawn in. The number of exhaust ports is not particularly limited.

[0073] Method for manufacturing electrode stacks A method for manufacturing an electrode laminate using a laser drying apparatus, as disclosed herein, The first laser light source is irradiated onto the electrode composite layer coated on the current collector layer through the first laser-transparent protective plate, and The laser light is irradiated from the second laser light source through the second laser-transparent protective plate onto the electrode composite layer coated on the current collector layer. A method for manufacturing an electrode stack, including [the specified element].

[0074] According to this disclosure, it is possible to provide a method for manufacturing an electrode laminate that can efficiently dry the electrode composite layer even when a large-area protective plate is constructed by arranging multiple protective plate pieces side by side in the planar direction.

[0075] The method disclosed herein is a method for manufacturing an electrode laminate using the laser drying apparatus described herein. For details regarding the laser drying apparatus, please refer to the description of the laser drying apparatus above.

[0076] The method of this disclosure includes irradiating an electrode mixture layer coated on a current collector layer with laser light from a first laser light source through a first laser-transparent protective plate, and irradiating the electrode mixture layer coated on the current collector layer with the same laser light from a second laser light source through a second laser-transparent protective plate. The first and second laser light sources and the first and second laser-transparent protective plates can be described by referring to the above description of the laser drying apparatus. By irradiating the electrode mixture layer with laser light, the dispersion medium contained in the electrode mixture layer volatilizes, and an electrode active material layer is formed.

[0077] The dispersion medium contained in the electrode composite layer is not particularly limited and may include, for example, nonpolar solvents such as heptane, xylene, and toluene, as well as polar solvents such as water, tertiary amine solvents, ether solvents, thiol solvents, ketone solvents (e.g., diisobutyl ketone) and ester solvents (e.g., butyl butyrate).

[0078] The content of the above-mentioned dispersion medium is not particularly limited, and may be such that the solid content of the electrode composite layer is 30% or more, 35% or more, 40% or more, 45% or more, or 50% or more, or it may be such that it is 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less.

[0079] The coating method for the electrode composite layer is not particularly limited and may include the doctor blade method, die coating method, gravure coating method, spray coating method, electrostatic coating method, bar coating method, etc.

[0080] The irradiation time of the laser light is not particularly limited, and may be extended, for example, until the reduction drying period of the electrode composite layer is reached. The irradiation time of the laser light may be, for example, 30 seconds or more, 1 minute or more, or 2 minutes or more, and may be 30 minutes or less, 20 minutes or less, or 10 minutes or less.

[0081] <Electrode Laminate> The electrode stack may have an electrode active material layer and a current collector layer. The electrode active material layer may be a positive electrode active material layer or a negative electrode active material layer. Furthermore, the electrode stack may be a bipolar electrode stack having a positive electrode active material layer and a negative electrode active material layer.

[0082] (electrode active material layer) If the electrode active material layer of this disclosure is a positive electrode active material layer, this positive electrode active material layer contains at least a positive electrode active material. If the electrode active material layer is a negative electrode active material layer, this negative electrode active material layer contains at least a negative electrode active material. The electrode active material layer may further optionally contain a binder, a solid electrolyte, and a conductive additive. The electrode active material layer may also contain various other additives. The respective contents of the positive electrode active material, negative electrode active material, binder, solid electrolyte, conductive additive, etc. in the electrode active material layer should be appropriately determined according to the desired battery performance.

[0083] The material of the positive electrode active material is not particularly limited as long as it is capable of intercalating and releasing lithium ions. Examples of positive electrode active materials include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), and nickel-cobalt-manganese oxide (NCM:LiCO2). 1 / 3 Ni 1 / 3 Mn 1 / 3 O2), lithium nickel-cobalt aluminum oxide (LiNi 0.8 (CoAl) 0.2 O2), Li 1+x Mn 2-x-y M y This may include, but is not limited to, heteroatom-substituted Li-Mn spinel with a composition represented by O4 (where M is one or more metallic elements selected from Al, Mg, Co, Fe, Ni, and Zn).

[0084] The shape of the positive electrode active material is not particularly limited, as long as it is a shape common for positive electrode active materials in batteries. The positive electrode active material may be, for example, particulate. The positive electrode active material may be primary particles or secondary particles formed by the aggregation of multiple primary particles. The average particle diameter D of the positive electrode active material 50For example, it may be 1 nm or more, 5 nm or more, or 10 nm or more, and it may also be 500 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. Note that the average particle diameter D 50 This is the particle diameter (median diameter) at 50% of the integrated value in the volume-based particle size distribution determined by laser diffraction and scattering.

[0085] As the negative electrode active material, various materials can be used whose potential for intercalating and releasing lithium ions (charge / discharge potential) is lower than that of the positive electrode active material described above. The material of the negative electrode active material is not particularly limited and may be metallic lithium, or any material capable of intercalating and releasing metallic ions such as lithium ions. Examples of materials capable of intercalating and releasing metallic ions such as lithium ions include alloy-based negative electrode active materials, carbon materials, or lithium titanate (Li4Ti5O4). 12 Examples include, but are not limited to, those listed above.

[0086] The alloy-based anode active material is not particularly limited and includes, for example, Si alloy-based anode active materials or Sn alloy-based anode active materials. Si alloy-based anode active materials include silicon, silicon oxide, silicon carbide, silicon nitride, or solid solutions thereof. Si alloy-based anode active materials may also contain metallic elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, Ti, etc. Sn alloy-based anode active materials include tin, tin oxide, tin nitride, or solid solutions thereof. Sn alloy-based anode active materials may also contain metallic elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, Si, etc.

[0087] The carbon material is not particularly limited and examples include hard carbon, soft carbon, and graphite.

[0088] The shape of the negative electrode active material is not particularly limited, but any shape common for negative electrode active materials in batteries is acceptable. The negative electrode active material may be in the form of parts or sheets, for example.

[0089] The material of the binder is not particularly limited. The binder may be, for example, polyvinylidene fluoride (PVdF), butadiene rubber (BR), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), etc., but is not limited to these. The binder is not particularly limited, and may be used alone or in combination of two or more types.

[0090] The material of the solid electrolyte is not particularly limited and may be, for example, a sulfide solid electrolyte, an oxide solid electrolyte, or a polymer electrolyte.

[0091] Examples of sulfide solid electrolytes include, but are not limited to, sulfide-based amorphous solid electrolytes, sulfide-based crystalline solid electrolytes, or argyrodite-type solid electrolytes. Specific examples of sulfide solid electrolytes include the Li2S-P2S5 system (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2 (Li 13 GeP3S 16 Li 10 GeP2S 12 etc.), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li 7-x PS 6-x Cl x Etc.; or combinations thereof, but not limited to these.

[0092] An example of an oxide solid electrolyte is Li7La3Zr2O 12 Li 7-x La3Zr 1-x Nb x O 12 Li 7-3x La3Zr2Al x O 12 Li 3x La 2 / 3-x TiO3, Li 1+x Al x Ti 2-x (PO4)3, Li 1+xAl x Ge 2-x (PO4)3, Li3PO4, or Li 3+x PO 4-x N x Examples include (LiPON), etc.; or combinations thereof, but are not limited to these.

[0093] The sulfide solid electrolyte and oxide solid electrolyte may be glass or crystallized glass (glass ceramics).

[0094] Examples of polymer electrolytes include, but are not limited to, polyethylene oxide (PEO), polypropylene oxide (PPO), and copolymers thereof.

[0095] The conductive additive is not particularly limited. Examples of conductive additives include, but are not limited to, vapor-grown carbon fibers (VGCF), acetylene black (AB), Ketjenblack (KB), carbon nanotubes (CNT), and carbon nanofibers (CNF). The conductive additive may be particulate or fibrous, and its size is not particularly limited. While the conductive additive is not particularly limited, it may be used alone or in combination of two or more types.

[0096] (Current collector layer) The material of the current collector layer is not particularly limited, but a material commonly used as a conductor for battery electrodes can be appropriately adopted. Examples of materials for the conductive layer include, but are not limited to, Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, etc. Furthermore, the current collector layer may be a metal foil or a substrate on which the above metals are plated or deposited.

[0097] The shape of the current collector layer is not particularly limited, but examples include foil-like, plate-like, or mesh-like shapes. Among these, a foil-like shape is preferred.

[0098] The thickness of the current collector layer is not particularly limited, but may be 0.1 μm or more, or 1 μm or more, or 1 mm or less, or 100 μm or less. [Examples]

[0099] Evaluation of drying efficiency <Laser drying equipment> Except for the fact that the laser-transparent protective plate is a single plate and there is no second laser light source, laser drying apparatuses with the same configuration as in Figure 1 were prepared as Reference Examples 1 to 5 and Reference Comparative Example 1, in which the distance y between the laser-transparent protective plate and the electrode composite layer was adjusted as shown in Table 2. The distance x between the laser light source and the electrode composite layer was 1500 mm. The material of the laser-transparent protective plate was quartz glass, and the transmittance of the laser light emitted from a 20 kW laser light source was 99.8% at a wavelength of 970 nm. The transmittance of the laser light was measured by spectrophotometric method using an ultraviolet-visible-near-infrared spectrophotometer (Shimadzu Corporation, SolidSpec-3700DUV). The temperature of the hot air supplied from the hot air supply device was 120°C.

[0100] <Measuring drying time> In Reference Examples 1-5 and Reference Comparative Example 1, the electrode composite layer (solid content 55%, basis weight: 35 mg / cm³) was dried using the laser drying apparatus. 2 The electrode mixture was dried, and the drying time was measured. The results are shown in Table 1. The temperature of the center of the electrode mixture layer was continuously measured using a radiation thermometer, and the drying time was defined as the point at which the center of the electrode mixture layer entered a period of reduced drying.

[0101] [Table 1]

[0102] From Reference Examples 1-5 and Reference Comparative Example 1, it can be understood that reducing x / y shortens the drying time. Therefore, by using a large-area laser-transparent protective plate and reducing x / y, drying efficiency can be increased. [Explanation of symbols]

[0103] 100 Laser drying apparatus 110 Furnace body 111 Exterior base material 112-1 First laser-transparent protective plate 112-2 Second Laser-Transmitting Protective Plate 112-3 Third Laser-Transmitting Protective Plate 120-1 First Laser Light Source 120-2 Second Laser Light Source 120-3 Third laser light source 121 Parent laser light source 122 Fiber 130 Conveying equipment 131 Conveyor belt 132 Conveyor rollers 140 Hot air supply equipment 141 Hot air generator 142 Air intake duct 143 Air intake nozzle 150 Exhaust equipment 200 laser beams 300 Electrode composite layer

Claims

1. A laser drying apparatus for drying an electrode composite layer, The laser drying apparatus comprises a furnace body, a first laser light source, and a second laser light source. The furnace body comprises a first laser-transparent protective plate and a second laser-transparent protective plate. The first laser-transparent protective plate and the second laser-transparent protective plate are arranged side by side in the planar direction. The first laser light source irradiates the electrode composite layer inside the furnace body with laser light through the first laser-transparent protective plate. The second laser light source irradiates the electrode composite layer inside the furnace body with laser light through the second laser-transparent protective plate, and The first and second laser light sources do not irradiate the boundary between the first and second laser-transparent protective plates with laser light. Laser drying device.

2. The apparatus according to claim 1, wherein the first and second laser light sources are formed by branching laser light from a single parent laser light source.

3. The apparatus according to claim 2, wherein the laser light from the parent laser light source is branched by a fiber or a prism.

4. The laser drying apparatus further comprises a third laser light source, The furnace body further comprises a third laser-transparent protective plate, The third laser light source irradiates the electrode composite layer with a laser through the third laser-transparent protective plate, and The apparatus according to claim 3, wherein the first to third laser light sources do not irradiate the boundary portion of the first to third laser-transparent protective plates with laser light.

5. A method for manufacturing an electrode laminate using the apparatus described in claim 1 or 2, Irradiating the electrode composite layer coated on the current collector layer with laser light from the first laser light source through the first laser-transparent protective plate, and The laser light is irradiated from the second laser light source through the second laser-transparent protective plate onto the electrode composite layer coated on the current collector layer. A method for manufacturing an electrode stack, including [the specified element].

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