Laser drying device

Abstract

The present disclosure aims to provide a laser drying device with high drying efficiency. A laser drying device (100) for drying an electrode mixture material layer, wherein the laser drying device (100) is provided with a furnace body (110) and a laser light source (120), the furnace body (110) is provided with a laser-transmissive protection plate (112) comprising a plurality of laser-transmissive protection plate pieces (112-1) for transmitting laser light, the laser light source (120) irradiates laser light (200) to the electrode mixture material layer in the furnace body (110) through the laser-transmissive protection plate (112), the plurality of laser-transmissive protection plate pieces (112-1) are arranged in the surface direction, and adjacent laser-transmissive protection plate pieces (112-1) are joined to each other through a gel substance (112-2) or arranged with gaps.

Description

Technical Field

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

[0002] Laser drying is a known method for drying electrode hybrid material layers coated on current collector layers. Compared with hot air drying, laser drying has the advantages of lower energy consumption and lower environmental impact. Various schemes have been proposed 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 in which an active substance paste is coated onto the surface of a long strip of metal while being conveyed; and a drying step performed in parallel with the coating step, wherein the active substance paste on the metal sheet is dried while being conveyed in a drying oven, hot air is conveyed along the conveying direction of the metal sheet in the drying oven, and light is irradiated onto the active substance paste on the metal sheet from at least one light source, thereby causing the temperature of the active substance paste to become higher than the temperature inside the drying oven. According to Patent Document 1, the temperature of the active substance paste is easily managed, enabling the active substance paste to dry uniformly in a short time.

[0004] Patent Document 2 discloses a method for manufacturing an electrode, characterized by comprising: a coating step, wherein an active substance mixture comprising an active substance, a solvent, a conductive material, and an adhesive is applied to a pre-defined coating area of ​​a conveyed strip of metal foil to form a coating portion of the active substance mixture; a first irradiation step, performed before the coating step, wherein a laser is irradiated onto an irradiation position of the strip of metal foil located upstream of the conveying direction of the strip of metal foil at both ends of the coating area along the short side direction; a second irradiation step, performed after the first irradiation step, wherein a laser is irradiated onto the two edges in the short side direction of the coating portion formed by the coating step; and a drying step, performed after the second irradiation step, wherein the coating portion is dried. According to Patent Document 2, a method for manufacturing an electrode capable of suppressing edge collapse of the coating portion and the shedding of conductive material from the edge is provided.

[0005] Patent Document 3 discloses an electrode drying method, comprising: a constant-rate drying step in which an electrode substrate coated with electrode slurry is dried while moving at an angle relative to a horizontal plane; and a deceleration drying step in which the electrode substrate is dried while moving horizontally. According to Patent Document 3, the floating phenomenon of adhesive components during the drying process of the electrode can be suppressed, thereby improving the adhesion between the electrode composite material layer and the electrode current collector.

[0006] [Existing Technical Documents]

[0007] [Patent Literature]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2024-39889

[0009] [Patent Document 2] Japanese Patent Application Publication No. 2019-29256

[0010] [Patent Document 3] Japanese Patent Application Publication No. 2023-504346 Summary of the Invention

[0011] [The problem the invention aims to solve]

[0012] The furnace body is equipped with a laser-transmitting protective plate, through which laser light is irradiated onto the electrode composite material layer inside the furnace body via the laser-transmitting protective plate, thereby insulating the laser source from the furnace body. Therefore, it is unnecessary to place a laser source inside the high-temperature furnace body.

[0013] Furthermore, by shortening the distance between the laser transmissive protective plate and the electrode mixture layer, the size of the furnace can be reduced, thereby improving drying efficiency. In this case, the distance between the laser transmissive protective plate and the laser source increases, and the area of ​​laser irradiation onto the laser transmissive protective plate becomes larger, thus requiring a large-area laser transmissive protective plate.

[0014] However, it is difficult to prepare laser transmissive protective plates made of materials such as quartz glass using large-area single sheets. In contrast, it is considered to join multiple laser transmissive protective plates together to form a laser transmissive protective plate, but when the temperature inside the furnace reaches a high level, thermal expansion can easily occur, resulting in thermal cracks.

[0015] Therefore, the purpose of this disclosure is to provide a laser drying apparatus with high drying efficiency.

[0016] [Methods used to solve problems]

[0017] This disclosure achieves the above objectives through the following means.

[0018] [Method 1]

[0019] A laser drying apparatus is used to dry an electrode hybrid material layer, wherein... The laser drying device includes a furnace body and a laser light source. The furnace body is equipped with a laser-transmitting protective plate, which includes multiple laser-transmitting protective plates that allow laser light to pass through. The laser source irradiates the electrode composite material layer inside the furnace through the laser transmission protection plate. The plurality of laser-transmitting protective plates are arranged in the planar direction, and, The adjacent laser-transmitting protective plates are bonded together by a gel material or arranged with gaps.

[0020] [Method 2]

[0021] According to the laser drying apparatus of method 1, the gel material is selected from fluorine-based gels, silicone-based gels, acrylic-based gels, and combinations thereof.

[0022] [Method 3]

[0023] According to the apparatus of method 1 or 2, adjacent laser-transmitting protective plates are arranged with gaps, and the furnace body is under negative pressure.

[0024] [Method 4]

[0025] The apparatus according to any one of methods 1 to 3, wherein the furnace body further comprises a hot air supply device.

[0026] [Method 5]

[0027] A method for manufacturing an electrode laminate, using the apparatus described in any one of methods 1 to 4, wherein... The method for manufacturing the electrode stack includes the following steps: irradiating the electrode hybrid material layer coated on the current collector layer with a laser.

[0028] [Invention Effects]

[0029] According to this disclosure, a laser drying apparatus with high drying efficiency can be provided. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the laser drying apparatus of this disclosure.

[0031] Figure 2 This is a schematic diagram illustrating the laser drying apparatus of this disclosure.

[0032] Figure 3 This is a schematic diagram illustrating the laser drying apparatus of this disclosure.

[0033] Figure 4 This is a schematic diagram illustrating the laser drying apparatus of this disclosure.

[0034] [Explanation of reference numerals in the attached figures]

[0035] 100 Laser Drying Equipment

[0036] 110 Furnace Body

[0037] 111 Exterior substrate

[0038] 112 Laser Transmissivity Protection Plate

[0039] 112-1 Laser Transmissivity Protective Plate

[0040] 112-2 Gel Material

[0041] 120 laser source

[0042] 130 Conveying Equipment

[0043] 131 Conveyor Belt

[0044] 132 Conveyor Rollers

[0045] 140 Hot air supply equipment

[0046] 141 Hot Air Generator

[0047] 142 Gas supply pipeline

[0048] 143 Air supply nozzle

[0049] 150 Exhaust Equipment

[0050] 200 laser

[0051] 300 Electrode Hybrid Material Layer Detailed Implementation

[0052] The embodiments of this disclosure will now be described in detail. Furthermore, this disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the spirit of this disclosure.

[0053] [[Laser Drying Equipment]]

[0054] A laser drying apparatus is used to dry an electrode hybrid material layer, wherein... The laser drying device includes a furnace body and a laser light source. The furnace body is equipped with a laser-transmitting protective plate, which includes multiple laser-transmitting protective plates that allow laser light to pass through. The laser source irradiates the electrode composite material layer inside the furnace through the laser transmission protection plate. The plurality of laser-transmitting protective plates are arranged in the planar direction, and, The adjacent laser-transmitting protective plates are bonded together by a gel material or arranged with gaps.

[0055] According to this disclosure, a laser drying apparatus with high drying efficiency can be provided.

[0056] The inventors have investigated the use of a laser-transmitting protective plate within the furnace body to insulate the laser source from the furnace interior during laser drying of an electrode composite material layer. Furthermore, to improve drying efficiency, a large distance between the laser source and the electrode composite material layer is required, necessitating a large-area laser-transmitting protective plate.

[0057] In response, the inventors discovered that the problem can be solved by constructing a laser transmission protective plate from multiple laser transmission protective plates. The adjacent laser transmission protective plates are joined together by a gel material or arranged with gaps, and the gel material or the gaps absorb the thermal expansion of the laser transmission protective plate, thereby suppressing thermal cracking of the laser transmission protective plate.

[0058] Therefore, the distance between the laser-transmitting protective plate and the electrode-mixed material layer inside the furnace can be brought closer, thus improving drying efficiency.

[0059] Specifically, for example, such as Figure 1 As shown, the laser drying apparatus 100 includes a furnace body 110 and a laser light source 120. Additionally, the laser drying apparatus 100 includes a conveying device 130, which, by rotating the conveyor rollers 132, allows the electrode mixture material layer disposed on the conveyor belt 131 to move at a constant speed in the conveying direction. Therefore, the electrode mixture material layer can be moved from the outside of the furnace body 110 to the inside of the furnace body 110 and from the inside of the furnace body 110 to the outside of the furnace body 110.

[0060] The furnace body 110 is composed of an outer substrate 111 and a laser transmissive protective plate 112. The electrode mixture material layer is transported into the furnace body 110 by the conveying equipment 130 and then irradiated with laser 200 from the laser light source 120 located outside the furnace body 110 through the laser transmissive protective plate 112.

[0061] The laser transmissivity protection plate 112 is composed of multiple laser transmissivity protection plates 112-1, which are arranged in the planar direction, and adjacent laser transmissivity protection plates 112-1 are bonded to each other via a gel material 112-2.

[0062] Furthermore, the laser drying apparatus 100 includes a hot air supply device 140, which comprises a hot air generator 141, a gas supply pipe 142, and a gas 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 gas supply pipe 142 and the gas supply nozzle 143. Additionally, the hot air is supplied in the conveying direction and in the direction opposite to the conveying direction. Vapor near the surface of the electrode composite material layer generated by laser irradiation is removed by the hot air and then discharged to the outside of the furnace body 110 via the exhaust device 150. This improves the drying efficiency of the electrode composite material layer.

[0063] It should be noted that the interior of the furnace body 110 becomes high-temperature due to the hot air mentioned above, but there is a laser transmissive protection plate 112 between the laser light source 120 and the interior of the furnace body 110. Therefore, the heat inside the furnace body 110 is not transferred, thus protecting the laser light source 120.

[0064] The laser drying apparatus disclosed herein is a laser drying apparatus for drying electrode mixed material layers.

[0065] Regarding this disclosure, "electrode composite material" refers to a composition that can form an electrode active material layer by directly or further containing other components. Furthermore, "electrode composite material layer" refers to a layer that includes a dispersion medium in addition to the "electrode composite material," thereby enabling coating and drying to form an electrode active material layer.

[0066] The laser drying apparatus disclosed herein includes a furnace body and a laser light source. Additionally, the laser drying apparatus may also include conveying equipment, hot air supply equipment, and exhaust equipment.

[0067] The energy density of the laser irradiating the electrode mixture layer inside the drying oven from the laser source is not particularly limited; for example, it can be 0.1 W / cm². 2 Above, 0.5W / cm 2 Above, 1.0W / cm 2 Above, 2.0W / cm 2 Above or 3.0W / cm 2 The above can also be 20.0 W / cm. 2 Below, 10.0W / cm 2 Below, 7.0W / cm 2 Below or 4.0W / cm 2 the following.

[0068] When the distance between the laser source and the electrode composite material layer is defined as x, and the distance between the laser transmissivity protection plate and the electrode composite material layer is defined as y, the following conditions can be met: y / x ≤ 0.15, 0.14, 0.13, 0.12, 0.10, 0.08, or 0.05. By satisfying the above relationship, the drying efficiency of the electrode composite material layer increases. Alternatively, y / x ≥ 0.01, 0.02, 0.03, or 0.04 can also be satisfied.

[0069] Specifically, for example, such as Figure 2 As shown, the electrode hybrid material layer 300 is disposed on the conveyor belt 131 and is irradiated by a laser. x is the shortest distance in the height direction from the laser irradiation section of the laser source 120 to the electrode hybrid material layer 300. y is the shortest distance in the height direction from the laser transmissivity protection plate 112 to the electrode hybrid material layer 300.

[0070] The distance x between the laser source and the electrode composite material layer is not particularly limited and can be appropriately determined considering factors such as the laser irradiation area. For example, the distance x can be 300mm or more, 500mm or more, 1000mm or more, 1500mm or more, 2000mm or more, or less than 5000mm, 4000mm or less, or less than 3000mm. Furthermore, the laser source can be located inside or outside the furnace body.

[0071] The distance y between the laser transmissivity protection plate and the electrode hybrid material layer is not particularly limited and can be appropriately determined by considering factors such as y / x and the thickness of the electrode hybrid material layer. For example, the distance y can be 5mm or more, 10mm or more, 30mm or more, 50mm or more, or 100mm or more, and can be less than 750mm, less than 500mm, less than 400mm, or less than 300mm.

[0072] [Furnace Body]

[0073] The furnace body is equipped with a laser-transmitting protective plate. For example... Figure 1 As shown, the furnace body may have an outer substrate and a laser-transmitting protective plate, with at least a portion of the outer substrate being a laser-transmitting protective plate. The laser-transmitting protective plate is positioned such that the laser light generated from the laser source can be transmitted through the laser-transmitting protective plate to the electrode hybrid material layer without any obstruction.

[0074] There are no particular limitations on the material of the outer casing substrate; for example, it can be steel, stainless steel, aluminum, etc. The outer casing substrate can undergo surface treatments such as galvanizing and powder coating. There are no particular limitations on the size of the furnace body; it can be appropriately determined considering factors such as the size of the electrode mixing material layer.

[0075] The dimensions of the furnace body are not particularly limited and can be appropriately determined by considering factors such as the size of the electrode mixing material layer. Additionally, the furnace body may have openings for transporting the electrode mixing material layer in and out via conveying equipment.

[0076] From the perspective of improving the drying efficiency of the electrode mixed material layer, the furnace body is preferably highly insulating, and the outer side of the outer substrate can be insulated. Examples of insulating materials include refractory bricks, ceramic fibers, and glass wool.

[0077] [Laser Transmissive Protection Plate]

[0078] The laser transmissivity protection plate includes multiple laser transmissivity protection plates that allow laser light to pass through. The multiple laser transmissivity protection plates are arranged in a planar direction. In this disclosure, the "planar direction" of a protection plate refers to a direction parallel to the main surface (largest surface) of the protection plate. Specifically, for example... Figure 1 Any direction perpendicular to the height of the furnace body, such as Figure 3 As shown, the laser transmissive protective plates 112-1 can be arranged in either the width direction or the conveying direction. The number of laser transmissive protective plates is not particularly limited and can be appropriately determined considering the size of the laser transmissive protective plates and the irradiation area of ​​the laser on the laser transmissive protective plates.

[0079] For laser light irradiated by the aforementioned laser source, the laser transmittance of the laser-transmittible protective plate can be above 95.0%, 96.0%, 97.0%, 98.0%, 99.0%, 99.5%, or 99.8%, or below 100.0% or 99.9%. The high laser transmittance allows for the efficient supply of light energy generated by the laser source to the electrode hybrid material layer without waste.

[0080] The transmittance of a laser, when the laser has a single wavelength, is the transmittance at that wavelength; when the laser has multiple wavelengths, it is the transmittance at the wavelength with the highest intensity. The transmittance of a laser can be measured spectrophotometrically using a UV-Vis-NIR spectrophotometer (Shimadzu SolidSpec-3700DUV).

[0081] The material of the laser transmission protective plate can be glass. Examples of glass types include quartz glass, soda-lime glass, lead glass, borosilicate glass, and alkali glass.

[0082] Laser-transmitting protective plates can be made of multi-layered glass. Multi-layered glass improves thermal insulation. Multi-layered glass can consist of multiple panes of glass with air, argon, krypton, or similar gases sealed between them.

[0083] There is no particular limitation on the thickness of the laser transmission protective plate; it can be determined appropriately based on the material of the laser transmission protective plate. For example, the thickness of the laser transmission protective plate can be 1mm or more, 3mm or more, 5mm or more, 7mm or more, or 10mm or more, and can be less than 30mm, 25mm or less, 20mm or less, or 15mm or less.

[0084] There is no particular limitation on the size of the laser-transmitting protective plate. It can be the size that allows the laser generated from the laser source to pass through the interior of the furnace without any omissions when multiple transmitting plates are combined.

[0085] The thermal conductivity of the laser-transmitting protective plate is not particularly limited and can be below 1.50 W / (m·K), 1.40 W / (m·K), 1.38 W / (m·K), 1.35 W / (m·K), 1.30 W / (m·K), 1.20 W / (m·K), 1.10 W / (m·K), or 1.00 W / (m·K), or above 0.10 W / (m·K), 0.30 W / (m·K), or 0.50 W / (m·K). Due to its low thermal conductivity, the laser source is less affected by the temperature inside the furnace.

[0086] Thermal conductivity can be measured using the heat flow meter method according to ASTEM-E-1530.

[0087] Adjacent laser-transmitting protective plates are bonded together via a gel material or arranged with gaps. Specifically, for example, such as... Figure 4 As shown in (a), adjacent laser-transmitting protective plates 112-1 can be bonded to each other via a gel material 112-2, as... Figure 4 As shown in (b), the laser transmissivity protective plate 112 does not contain a gel material, and adjacent laser transmissivity protective plates 112-1 can be arranged with gaps. Furthermore, the shape of the gel material or the shape of the gaps are not particularly limited and can be... Figure 4 (c) such a tilted shape.

[0088] When adjacent laser-transmitting protective plates are bonded together by a gel material, positive pressure can be maintained inside the furnace. By maintaining positive pressure inside the furnace, it is possible to prevent the gel material from escaping from between the adjacent laser-transmitting protective plates into the furnace.

[0089] When adjacent laser-transmitting protective plates are arranged with gaps, a negative pressure can be maintained inside the furnace. By creating a negative pressure inside the furnace, heat leakage from the furnace through the gaps between the laser-transmitting protective plates can be suppressed.

[0090] The spacing between adjacent laser-transmitting protective plates is not particularly limited and can be appropriately determined considering factors such as the thermal expansion coefficient of the laser-transmitting protective plates and the softness of the gel material. For example, the spacing between adjacent laser-transmitting protective plates can be 50 μm or more, 100 μm or more, 500 μm or more, 1 mm or more, 2 mm or more, or 3 mm or more, and can be less than 10 mm, less than 7 mm, or less than 5 mm. Here, the above spacing is equivalent to... Figure 4 (a) The distance a in the direction of transport of the gel material Figure 4 (b) The distance a in the conveying direction of the gap. Furthermore, the spacing between adjacent laser transmissivity protection plates in the conveying direction can be approximately constant in the width direction. Moreover, the spacing between adjacent laser transmissivity protection plates in the conveying direction can be approximately the same as the spacing between adjacent laser transmissivity protection plates in the width direction.

[0091] The gel material can be selected from fluorinated gels, silicone gels, acrylic gels, and combinations thereof. Preferably, the gel material is a material that readily transmits laser light, has low thermal conductivity, and is soft.

[0092] For laser light irradiated by the aforementioned laser source, the laser transmittance of the gel material can be 80.0% or higher, 85.0% or higher, 90.0% or higher, 95.0% or higher, 99.0% or higher, 99.5% or higher, or 99.8% or higher, or it can be less than 100.0% or less than 99.9%. High laser transmittance allows for the efficient supply of light energy generated by the laser source to the electrode composite material layer without waste. The laser transmittance of the gel material can be 80.0% or higher, 85.0% or higher, 90.0% or higher, or 95.0% or higher than the laser transmittance of the laser transmissive protective plate, or it can be less than 100.0% of the laser transmittance of the laser transmissive protective plate. The small difference between the laser transmittance of the gel material and the laser transmittance of the laser transmissive protective plate helps to suppress uneven laser irradiation of the electrode composite material layer.

[0093] The transmittance of a laser, when the laser has a single wavelength, is the transmittance at that wavelength; when the laser has multiple wavelengths, it is the transmittance at the wavelength with the highest intensity. The transmittance of a laser can be measured spectrophotometrically using a UV-Vis-NIR spectrophotometer (Shimadzu SolidSpec-3700DUV).

[0094] The refractive index of a gel material is not particularly limited; for example, it can be below 1.60, 1.55, 1.50, or 1.45, or above 1.00, 1.10, 1.20, or 1.30. The refractive index can be calculated by measuring the angle of incidence and the angle of refraction using the reflection method.

[0095] The thermal conductivity of the gel material is not particularly limited and can be below 1.40 W / (m·K), 1.20 W / (m·K), 1.00 W / (m·K), 0.80 W / (m·K), 0.70 W / (m·K), 0.60 W / (m·K), or 0.50 W / (m·K), or above 0.10 W / (m·K), 0.30 W / (m·K), or 0.50 W / (m·K). Due to its low thermal conductivity, the laser source is protected from the temperature inside the furnace. Thermal conductivity can be measured using the heat flow meter method according to ASTEM-E-1530.

[0096] There is no particular limitation on the heat resistance temperature of the gel material; it can be appropriately determined by considering the temperature inside the furnace. The temperature inside the furnace can be, for example, above 50℃, above 100℃, above 130℃, above 150℃, above 160℃, above 180℃, above 200℃, above 220℃, above 240℃, above 260℃, above 280℃, or above 300℃, or below 500℃, below 450℃, below 400℃, or below 350℃.

[0097] The hardness of the gel material is not particularly limited; for example, its Shore A hardness can be above 0, above 1, above 3, above 5, above 7, or above 10, and below 30, below 25, or below 20. By making the gel material soft, damage to the laser transmission protective plate caused by thermal expansion can be suppressed. The hardness (Shore A) of the gel material can be measured according to JIS-K-6253.

[0098] Fluorine-based gels are gels containing fluorine compounds and can be coated with commercially available optical coatings, such as Novec Fluorochemical Gel (manufactured by 3M).

[0099] Silicone-based gels are gels containing silicon compounds and can be applied using commercially available optical coatings. Examples of silicone-based gels include silicone gels and Sylgard 527 (manufactured by Dow Chemical).

[0100] Acrylic gels are gels containing acrylic resins and can be used with commercially available optical coatings. An example of an acrylic gel is Cyrilite (manufactured by Rohm).

[0101] [Laser source]

[0102] The laser source irradiates the electrode composite material layer inside the furnace through a laser-transmittant protective plate. Because the laser-transmittant protective plate has high laser transmittance, the light energy generated by the laser source can be supplied to the electrode composite material layer without any waste.

[0103] The laser source can be positioned outside the furnace body. When the temperature inside the furnace becomes very high, placing the insulated laser source outside the furnace body can protect it from the effects of high heat.

[0104] There are no particular limitations on the type of laser source; for example, it can be a Yb fiber laser, a YAG laser, or a carbon dioxide laser. The laser wavelength can be 0.5μm or higher, 0.6μm or higher, 0.7μm or higher, 0.8μm or higher, or 0.9μm or higher, and can be below 1.5μm, below 1.4μm, below 1.3μm, below 1.2μm or below 1.1μm. The laser can be a single wavelength or multiple wavelengths.

[0105] There are no particular limitations on the output of the laser source; it can be appropriately determined based on factors such as the irradiation area and the duration of laser irradiation. For example, the output of the laser source can be above 0.1kW, above 1kW, above 5kW, above 10kW, above 15kW, above 20kW, or above 30kW, or below 100kW, below 70kW, or below 50kW.

[0106] There is no particular limit to the number of laser sources; it can be determined appropriately based on the laser irradiation area and the laser irradiation time. The number of laser sources can be, for example, more than one, more than two, more than three, more than five, or more than ten, or less than thirty or twenty.

[0107] The shape of the irradiation area of ​​the laser on the electrode hybrid material layer can be, for example, rectangular. Furthermore, the size of the irradiation area is not particularly limited and can be appropriately determined based on the size of the electrode hybrid material layer.

[0108] [Hot air supply equipment]

[0109] The hot air supply equipment supplies hot air into the furnace. By supplying hot air to the electrode mixture layer, the vapor on the surface of the electrode mixture layer can be removed, thereby improving the drying efficiency.

[0110] The temperature of the hot air supplied from the hot air supply equipment can be above 50℃, above 100℃, above 130℃, above 150℃, above 160℃, above 180℃, above 200℃, above 220℃, above 240℃, above 260℃, above 280℃, or above 300℃, or below 500℃, below 450℃, below 400℃, or below 350℃.

[0111] There are no particular limitations on the hot air supply equipment. For example, air heated by gas combustion, petroleum combustion, or electric heating can be supplied to the electrode composite material layer via a blower, air duct, and air nozzle. From the viewpoint of drying the electrode composite material layer, the hot air is preferably low in humidity.

[0112] There is no particular limitation on the direction of hot air supply. For example, when conveying the electrode mixing material layer inside the furnace, it can be in a direction opposite to the conveying direction. In addition, multiple air nozzles can be configured, and each can be configured to provide a different supply direction.

[0113] There is no particular limitation on the wind speed of the hot air; for example, it can be above 5 m / s, above 10 m / s, above 15 m / s, or above 20 m / s. If the wind speed is high, the drying efficiency of the electrode hybrid material layer will be higher. Alternatively, the wind speed of the hot air can be below 60 m / s, below 50 m / s, below 40 m / s, or below 30 m / s.

[0114] [Conveying equipment]

[0115] The conveying equipment is not particularly limited; for example, it can be a roller conveyor, a belt conveyor, etc. The electrode hybrid material layer can be disposed on the conveying path, for example, to be moved into the furnace body and out of the furnace body.

[0116] The electrode mixture layer can be irradiated with laser while moving inside the furnace using a conveying device. In this case, the moving speed can be appropriately determined taking into account factors such as the output of the laser source and the energy required for drying the electrode mixture layer. For example, the moving speed can be 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 less than 3.0 m / s, less than 2.5 m / s, or less than 2.0 m / s.

[0117] The conveying equipment can also be connected to other devices such as an electrode mixing material layer coating device and an electrode layer stack winding device.

[0118] [Exhaust Equipment]

[0119] Laser drying equipment can also be equipped with an exhaust system. By having an exhaust system, the vapor generated from the electrode-mixed material layer can be recovered, improving drying efficiency. Furthermore, the vapor can be water vapor or other gases.

[0120] Exhaust equipment, for example, can draw steam from the exhaust port using an exhaust fan and discharge it to the outside of the furnace through an exhaust pipe. The output of the exhaust fan, the size of the exhaust port, and the size of the exhaust pipe can be appropriately determined by taking into account factors such as the amount of steam generated and the internal pressure of the furnace.

[0121] From the perspective of improving drying efficiency, the exhaust port is preferably located on the upper part of the electrode mixture layer and in a position that does not obstruct laser irradiation. The distance between the exhaust port and the electrode mixture layer can be sufficient to attract vapor. The number of exhaust ports is not particularly limited.

[0122] [Manufacturing Method of Electrode Laminates]

[0123] A method for manufacturing an electrode stack, using the laser drying apparatus of this disclosure, wherein, The method for manufacturing the electrode stack includes the following steps: irradiating the electrode hybrid material layer coated on the current collector layer with a laser.

[0124] According to this disclosure, a method for manufacturing an electrode laminate with high drying efficiency can be provided.

[0125] The method disclosed herein is a method for manufacturing an electrode stack using the laser drying apparatus of this disclosure. For details regarding the laser drying apparatus, please refer to the description of the laser drying apparatus described above.

[0126] The method disclosed herein includes the step of irradiating an electrode mixture layer coated on a current collector layer with a laser. Regarding the electrode mixture layer and the laser, refer to the description of the aforementioned laser drying apparatus. By irradiating the electrode mixture layer with a laser, the dispersion medium contained in the electrode mixture layer evaporates, forming an electrode active material layer.

[0127] The dispersion medium contained in the electrode mixed material layer is not particularly limited. For example, it can be non-polar 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).

[0128] The content of the aforementioned dispersion medium is not particularly limited. For example, it can be an amount in which the solid content of the electrode mixed material layer is 30% or more, 35% or more, 40% or more, 45% or more, or 50% or more. Alternatively, it can be an amount in which the solid content of the electrode mixed material layer is 80% or less, 75% or less, 70% or less, 65% or less, or 60% or less.

[0129] There are no particular limitations on the coating method for the electrode hybrid material layer; it can be blade coating, mold coating, gravure coating, spray coating, electrostatic coating, bar coating, etc.

[0130] There is no particular limitation on the laser irradiation time; for example, it can be used during the deceleration drying process of the electrode composite material layer. The laser irradiation time can be, for example, more than 30 seconds, more than 1 minute, or more than 2 minutes, or less than 30 minutes, less than 20 minutes, or less than 10 minutes.

[0131] [Electrode stack]

[0132] The electrode stack can have an electrode active material layer and a current collector layer. The electrode active material layer can be a positive electrode active material layer or a negative electrode active material layer. Alternatively, the electrode stack can also be a bipolar electrode stack having both a positive electrode active material layer and a negative electrode active material layer.

[0133] [Electrode active material layer]

[0134] When the electrode active material layer of this disclosure is a positive electrode active material layer, the positive electrode active material layer contains at least a positive electrode active material. Furthermore, when the electrode active material layer is a negative electrode active material layer, the negative electrode active material layer contains at least a negative electrode active material. The electrode active material layer may further optionally contain binders, solid electrolytes, and conductive additives, etc. The electrode active material layer may also contain various other additives. The content of each of the positive electrode active material, negative electrode active material, binder, solid electrolyte, conductive additive, etc., in the electrode active material layer can be appropriately determined according to the target battery performance.

[0135] There are no particular limitations on the materials used for positive electrode active materials, as long as they can absorb and release lithium ions. Examples of positive electrode active materials include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LFP), lithium manganese iron phosphate (LMFP), and lithium nickel cobalt manganese oxide (NCM: LiCO3). 1 / 3 Ni 1 / 3 Mn 1 / 3 O2), nickel cobalt lithium aluminum oxide (LiNi) 0.8 (CoAl) 0.2 O2) and Li 1+x Mn 2-x-y M y Li-Mn spinel, etc., but not limited to, with O4 (M being one or more metallic elements selected from Al, Mg, Co, Fe, Ni and Zn) as a heteroelement substitution.

[0136] The shape of the positive electrode active material is not particularly limited as long as it is a typical shape used for positive electrode active materials in batteries. For example, the positive electrode active material can be in particle form. It can be primary particles or secondary particles formed by the aggregation of multiple primary particles. The average particle size D of the positive electrode active material... 50For example, it can be 1 nm or larger, 5 nm or larger, or 10 nm or larger; alternatively, it can be less than 500 μm, less than 100 μm, less than 50 μm, or less than 30 μm. Additionally, the average particle size D... 50 It is the particle size (median particle size) at the 50% cumulative value of the particle size distribution of the volume reference obtained by laser diffraction scattering method.

[0137] As the negative electrode active material, various materials whose lithium ion absorption and release potential (charge / discharge potential) is lower than that of the positive electrode active material disclosed herein can be used. The material of the negative electrode active material is not particularly limited and can be metallic lithium, or any material capable of absorbing and releasing lithium ions or other metal ions. Examples of materials capable of absorbing and releasing lithium ions or other metal ions include alloy-based negative electrode active materials, carbon materials, or lithium titanate (Li4Ti5O). 12 (etc.), but not limited to these.

[0138] There are no particular limitations on alloy-based anode active materials; examples include Si alloy-based and Sn alloy-based anode active materials. Si alloy-based anode active materials include silicon, silicon oxides, silicon carbides, silicon nitrides, or their solid solutions. Furthermore, Si alloy-based anode active materials can contain metallic elements other than silicon, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Sn, and Ti. Sn alloy-based anode active materials include tin, tin oxides, tin nitrides, or their solid solutions. Furthermore, Sn alloy-based anode active materials can contain metallic elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, and Si.

[0139] As a carbon material, there are no particular limitations; examples include hard carbon, soft carbon, and graphite.

[0140] There are no particular limitations on the shape of the negative electrode active material; any general shape suitable for a battery's negative electrode active material is acceptable. The negative electrode active material can be, for example, in particle or sheet form.

[0141] There are no particular limitations on the material of the adhesive. Adhesives can be, for example, polyvinylidene fluoride (PVdF), butadiene rubber (BR), polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), etc., but are not limited to these. There are no particular limitations on the adhesive; a single type can be used, or two or more types can be used in combination.

[0142] There are no particular limitations on the materials of solid electrolytes; for example, they can be sulfide solid electrolytes, oxide solid electrolytes, or polymer electrolytes.

[0143] Examples of sulfide solid electrolytes include amorphous sulfide solid electrolytes, crystalline sulfide solid electrolytes, and sulfide-silver-germanium ore type solid electrolytes, but are not limited to these. Specific examples of sulfide solid electrolytes include the Li₂S-P₂S₅ system (Li₇P₃S₅). 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.

[0144] Examples of oxide solid electrolytes include 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+x Al x Ge 2-x (PO4)3, Li3PO4 or Li 3+x PO 4-x N x (LiPON) and combinations thereof, but not limited to these.

[0145] Sulfide solid electrolytes and oxide solid electrolytes can be glass or crystallized glass (glass ceramics).

[0146] Examples of polymer electrolytes include polyethylene oxide (PEO), polypropylene oxide (PPO), and their copolymers, but are not limited to these.

[0147] There are no particular limitations on the conductive additives. Examples of conductive additives include, but are not limited to, vapor-grown carbon fiber (VGCF), acetylene black (AB), Ketjen black (KB), carbon nanotubes (CNT), and carbon nanofibers (CNF). Conductive additives can be in particulate or fibrous form, and their size is not particularly limited. There are no particular limitations on the use of conductive additives; a single additive may be used, or two or more additives may be used in combination.

[0148] (Current collector layer)

[0149] The material of the current collector layer is not particularly limited, and common materials can be used as the conductors of the battery electrodes. Examples of materials that can be used as the conductor layer include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, and stainless steel, but are not limited to these. In addition, the current collector layer can be a layer formed by depositing or vapor-depositing the aforementioned metals on a metal foil or substrate.

[0150] The shape of the current collector layer is not particularly limited; for example, it can be foil-shaped, plate-shaped, or mesh-shaped. Among these, foil-shaped is preferred.

[0151] The thickness of the current collector layer is not particularly limited; it can be greater than 0.1 μm or greater than 1 μm, or less than 1 mm or less than 100 μm.

[0152] [Example]

[0153] The present invention will be specifically described through examples and comparative examples, but the present invention is not limited thereto.

[0154] [[Laser Drying Equipment]]

[0155] Place the two laser-transmitting protective plates as follows: Figure 4 The laser transmissivity protective plates used in Examples 1-6 are fabricated by combining them as shown in (a) to (c). The laser transmissivity protective plates are made of quartz glass, with dimensions of 1200 mm in width, 750 mm in transport direction, and 1.5 mm in thickness. Then, by combining two laser transmissivity protective plates, a laser transmissivity protective plate with a transport direction of 1500 mm and a width of 1200 mm is formed. Furthermore, Figure 4 The gelling material in (a) and (c) is a fluorinated gel (Novec Fluorochemical Gel, manufactured by 3M). Additionally, Figure 4 The cross-sectional shape in the height direction of the gap between the gel material or laser-transmitting protective plates is in Figure 4 (a) and (b) are rectangles, in Figure 4 (c) is a parallelogram.

[0156] Here, Figure 4In (a), the laser transmission protective plates with a distance (distance a) of 0.1 mm, 1 mm, and 3 mm between adjacent laser transmission protective plates are used as laser transmission protective plates in Examples 1-3. Figure 4 (b) uses laser transmission protection plates with distances a of 0.1 mm, 1 mm, and 3 mm as laser transmission protection plates in Examples 4-6. Figure 4 (c) laser transmissivity protection plates with distances a of 0.1 mm, 1 mm, and 3 mm were used as laser transmissivity protection plates in Examples 7-9. Additionally, a laser transmissivity protection plate in Comparative Example 1 was fabricated where the laser transmissivity protection plates were connected seamlessly without any gaps via a gel material.

[0157] And, will Figure 1 The laser drying apparatus with that structure is the same as those in Examples 1-9 and Comparative Example 1. Furthermore, the laser source has an output power of 50kW and is positioned in the center of the laser transmissivity protection plate in Examples 1-9 and Comparative Example 1, such that it can irradiate an area of ​​1300mm in the conveying direction and 1000mm in the width direction. Additionally, the hot air supply equipment is capable of supplying 200°C hot air into the furnace.

[0158] [[Durability Evaluation of Laser Transmissive Protective Plate]]

[0159] In the laser drying apparatus of Examples 1-9 and Comparative Example 1, laser irradiation and hot air supply to the furnace were carried out continuously for 2 hours, followed by natural cooling to ambient temperature. After repeating this process 10 times, the laser transmissivity protection plate was visually inspected for damage, and the durability of the laser transmissivity protection plate was evaluated.

[0160] The evaluation results are shown in Table 1.

[0161] [Table 1]

[0162] As demonstrated in Examples 1-9 and Comparative Example 1, by having adjacent laser-transmitting protective plates bonded together by a gel material or arranged with gaps in the laser-transmitting protective plates in the laser drying apparatus, thermal cracks will not occur in the laser-transmitting protective plates even at high temperatures inside the furnace. Therefore, even without preparing a single large-area laser-transmitting protective plate, multiple laser-transmitting protective plates can be combined to form a large-area laser-transmitting protective plate.

[0163] Evaluation of drying efficiency

[0164] [Laser Drying Equipment]

[0165] In addition to the laser transmissivity protection board being a single board, it is also compatible with... Figure 1 With the same configuration, a laser drying apparatus was prepared as Reference Examples 1 to 5 and Reference Comparative Example 1, with the distance y between the laser transmissivity protection plate and the electrode hybrid material layer adjusted as shown in Table 2. The distance x between the laser source and the electrode hybrid material layer was 1500 mm. The laser transmissivity protection plate was made of quartz glass, and the transmittance of the laser emitted from the 20 kW laser source was 99.8% at a wavelength of 970 nm. The laser transmittance was measured using a spectrophotometer (Shimadzu SolidSpec-3700DUV) with ultraviolet-visible-near-infrared properties. The temperature of the hot air supplied from the hot air supply equipment was 120°C.

[0166] [Electrode Hybrid Material Layer]

[0167] Lithium cobalt oxide (LiCoO2) as the electrode active material and styrene-butadiene copolymer (SBR) as the binder were mixed at a mass ratio of 97.5:2.5 with ion-exchanged water to prepare an electrode composite material layer with a solids content of 55%. It should be noted that the weight per unit area of ​​the electrode composite material layer is 35 mg / cm³. 2 .

[0168] [Evaluation of drying time]

[0169] The electrode hybrid material layer described above was coated with an aluminum foil serving as a current collector layer with a thickness of 400 μm. The foil was then placed into the laser drying apparatus of Reference Examples 1 to 5 and Reference Comparative Example 1, and the region including the center of the electrode hybrid material layer was irradiated with laser.

[0170] The temperature of the center of the electrode mixture layer was continuously measured using a radiation thermometer, and the point at which the center of the electrode mixture layer entered the deceleration drying stage was defined as the drying time. The drying times of the electrode mixture layers in the laser drying apparatus of Reference Examples 1-5 and Reference Comparative Example 1 are shown in Table 2.

[0171] [Table 2]

[0172] As can be seen from Reference Examples 1-5 and Reference Comparative Example 1, the drying time is shortened by reducing x / y. Therefore, by using a large-area laser-transmissive protective plate to reduce x / y, the drying efficiency can be improved.

Claims

1. A laser drying apparatus for drying an electrode composite material layer, wherein, The laser drying device includes a furnace body and a laser light source. The furnace body is equipped with a laser-transmitting protective plate, which includes multiple laser-transmitting protective plates that allow laser light to pass through. The laser source irradiates the electrode composite material layer inside the furnace through the laser transmission protection plate. The plurality of laser-transmitting protective plates are arranged in the planar direction, and, The adjacent laser-transmitting protective plates are bonded together by a gel material or arranged with gaps.

2. The laser drying apparatus according to claim 1, wherein, The gel material is selected from fluorinated gels, silicone gels, acrylic gels, and combinations thereof.

3. The laser drying apparatus according to claim 1 or 2, wherein, The adjacent laser-transmitting protective plates are spaced apart, and the furnace body is under negative pressure.

4. The laser drying apparatus according to claim 1 or 2, wherein, The furnace body also has a hot air supply device.

5. A method for manufacturing an electrode stack, using the laser drying apparatus according to claim 1 or 2, wherein, The method for manufacturing the electrode stack includes the following steps: irradiating the electrode hybrid material layer coated on the current collector layer with a laser.

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