Laser drying device

Abstract

The present disclosure aims to provide a laser drying device with high drying efficiency, the laser drying device (100) is used for drying an electrode composite layer, and the laser drying device (100) comprises a furnace body (110), a rectifier plate (120), a laser source (130) and a hot air supply device (140). The rectifier plate (120) is arranged in the interior of the furnace body (110), is arranged between the electrode composite layer and the laser source (130), and is configured to allow laser (200) to pass through. The laser source (130) irradiates laser (200) to the electrode composite layer through the rectifier plate (120), and the hot air supply device (140) supplies hot air between the rectifier plate (100) and the electrode composite layer.

Description

Technical Field

[0001] This disclosure relates to 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 has the advantages of lower energy consumption and lower environmental impact. Various solutions have been proposed to improve the drying efficiency of laser drying.

[0003] Patent Document 1 discloses a method for manufacturing an electrode body, comprising: a conveying step in which an electrode body coated with at least one electrode material is conveyed by a conveying unit; and a drying step in which the electrode body is conveyed by the conveying unit while the electrode material is dried, the drying step including: an irradiation step in which the electrode material is dried by irradiating it with a laser when the electrode body is conveyed to at least one first position in the conveying direction of the conveying unit; and a recovery step in which steam generated by irradiating the electrode material with the laser is recovered using a steam recovery unit provided at at least one second position adjacent to the first position in the conveying direction. Patent Document 1 states that, according to the disclosure of Patent Document 1, when drying the electrode material using a laser, a decrease in drying efficiency can be suppressed.

[0004] Patent Document 2 discloses a method for manufacturing an electrode sheet, comprising: a preparation step of preparing a coated sheet having a coating portion on which electrode material is coated on a first surface of a current collector having a length direction along a first direction; and a drying step of conveying the coated sheet along the first direction while irradiating it with laser light from a plurality of laser heads arranged along the first direction, thereby drying the coating portion to obtain the electrode sheet. In the drying step, for the laser irradiation portions on the conveyed coated sheet that have been irradiated with laser light from each laser head, hot air with a temperature of 50°C or higher and 140°C or lower and a wind speed of 5 m / s or higher is supplied until the next laser irradiation. Patent Document 2 states that, according to the disclosure of Patent Document 2, it is possible to manufacture an electrode sheet that suppresses the increase in drying time and suppresses the decrease in peel strength between the electrode layer and the current collector.

[0005] On the other hand, a scheme was proposed to equip the drying device with a rectifier plate when supplying hot air to the electrode composite layer and drying the electrode composite layer.

[0006] Patent Document 3 discloses a drying apparatus having an internal conveying path with multiple conveying rollers. The drying apparatus includes: a hot air supply unit, with multiple units arranged facing and along the conveying path, supplying hot air to the conveying path; and a rectifier plate disposed between adjacent hot air supply units, guiding the hot air along the conveying direction. The rectifier plate has a hot air exhaust section for discharging hot air. When the direction orthogonal to the conveying direction of the conveying path is defined as the width direction, the shape of the hot air exhaust section satisfies the condition that its length in the conveying direction at the center of the width direction is greater than its length in the conveying direction at the ends of the width direction. Patent Document 3 states that, according to the disclosure of Patent Document 3, it is possible to suppress retention caused by hot air interference and to suppress uneven drying.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2023-169591 Patent Document 2: Japanese Patent Application Publication No. 2024-020819 Patent document 3: Japanese Patent Application Publication No. 2023-014755. Summary of the Invention The technical problem that the invention aims to solve

[0008] When using a laser source to dry the electrode composite layer, a larger distance is needed between the laser source and the workpiece in order to expand the laser irradiation area on the electrode composite layer. In this case, the size of the furnace body needs to be increased.

[0009] On the other hand, during laser drying, supplying hot air to the electrode composite layer inside the furnace can improve drying efficiency. However, when the furnace size is increased as described above, the hot air diffuses, making it difficult to supply hot air to the electrode composite layer, sometimes resulting in the unsatisfactory drying efficiency.

[0010] Therefore, the purpose of this disclosure is to provide a laser drying apparatus with high drying efficiency. Technical means for solving technical problems

[0011] This disclosure achieves the above objectives through the following technical solutions. <Option 1> A laser drying apparatus is provided for drying an electrode composite layer. The laser drying apparatus includes a furnace body, a rectifier plate, a laser source, and a hot air supply device. The rectifier plate is disposed inside the furnace body, between the electrode composite layer and the laser source, and is configured to allow laser light to pass through. The laser source irradiates the electrode composite layer with laser light through the rectifier plate, and the hot air supply device supplies hot air between the rectifier plate and the electrode composite layer. Option 2 According to the laser drying apparatus described in Scheme 1, the furnace body further includes a laser transmittance protection plate, and the laser source irradiates the electrode composite layer with laser light through the laser transmittance protection plate and the rectifier plate. Option 3 According to the laser drying apparatus described in Scheme 1 or Scheme 2, when the distance between the laser source and the electrode composite layer is set as x, and the distance between the rectifier plate and the electrode composite layer is set as y, the following relationship is satisfied: y / x≤0.15. Option 4 According to any one of Schemes 1 to 3, in the laser drying apparatus, the transmittance of the laser from the rectifier plate is 95.0% or higher for laser light irradiated from the laser source. Option 5 A method for manufacturing an electrode stack, using any one of embodiments 1 to 4, wherein the manufacturing method includes: irradiating an electrode composite layer coated on a current collector layer with a laser; and supplying hot air into the interior of the furnace. Invention Effects

[0012] According to this disclosure, a laser drying apparatus with high drying efficiency can be provided. Attached Figure Description

[0013] Figure 1 This is a schematic diagram illustrating the laser drying apparatus of this disclosure. Figure 2 This is a schematic diagram illustrating the laser drying apparatus of this disclosure. Figure 3 This is a schematic diagram illustrating the laser drying apparatus of this disclosure. Detailed Implementation

[0014] Laser Drying Equipment A laser drying apparatus is provided for drying an electrode composite layer. The laser drying apparatus includes a furnace body, a rectifier plate, a laser source, and a hot air supply device. The rectifier plate is disposed inside the furnace body, between the electrode composite layer and the laser source, and is configured to allow laser light to pass through. The laser source irradiates the electrode composite layer with laser light through the rectifier plate, and the hot air supply device supplies hot air between the rectifier plate and the electrode composite layer.

[0015] According to this disclosure, a laser drying apparatus with high drying efficiency can be provided.

[0016] The inventors of this disclosure explored a method to improve drying efficiency by supplying hot air into the furnace body using a hot air supply device when laser drying electrode composite layers. However, in order to expand the laser irradiation area of ​​the electrode composite layer, while ensuring a relatively large distance between the laser source and the electrode composite layer, it is difficult to supply hot air to the electrode composite layer due to hot air diffusion.

[0017] In response, the inventors of this disclosure discovered that the above-mentioned problem can be solved by arranging a rectifier plate between the electrode composite layer and the laser source inside the furnace body and supplying hot air between the rectifier plate and the electrode composite layer. By arranging the rectifier plate, the flow path of the hot air can be regulated, thereby enabling the hot air to be supplied appropriately to the electrode composite layer.

[0018] In addition, the laser is supplied to the electrode composite layer via a rectifier plate. Because the rectifier plate has high laser transmittance, the laser can be supplied to the electrode composite layer without any waste.

[0019] Specifically, for example Figure 1 Thus, the laser drying apparatus 100 includes a furnace body 110, a rectifier plate 120, a laser source 130, and a hot air supply device 140. Furthermore, the laser drying apparatus 100 has a conveying device 150, which, by rotating the conveyor rollers 152, allows the electrode composite layer disposed on the conveyor belt 151 to move at a constant speed along the conveying direction. Therefore, it is possible to move the electrode composite layer from outside the furnace body 110 into the furnace body 110 and to move the electrode composite layer from inside the furnace body 110 out of the furnace body 110.

[0020] Inside the furnace body 110, a rectifier plate 120 is arranged between the laser source 130 and the conveyor belt 151. The electrode composite material layer that has been moved into the furnace body 110 by the conveyor equipment 150 is irradiated by laser 200 from the laser source 130 via the rectifier plate 120.

[0021] The hot air supply device 140 consists of 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. Furthermore, hot air is supplied between the rectifier plate 120 and the electrode composite layer. The hot air is supplied in both the conveying direction and the direction opposite to the conveying direction. By supplying hot air, the steam near the surface of the electrode composite 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 160. Furthermore, by configuring the rectifier plate 120, the flow path of the hot air is regularized, which improves the drying efficiency of the electrode composite layer.

[0022] The embodiments of this disclosure will now be described in detail. It should be noted that this disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the spirit of this disclosure.

[0023] The laser drying apparatus disclosed herein is a laser drying apparatus for drying electrode composite layers.

[0024] In this disclosure, "electrode composite" refers to a composition that can directly or by further containing other components to form an electrode active material layer. Furthermore, "electrode composite layer" refers to a layer that, in addition to the "electrode composite," also contains a dispersion medium, thereby enabling the formation of an electrode active material layer through coating and drying.

[0025] The laser drying apparatus disclosed herein includes a furnace body, a rectifier plate, a laser source, and a hot air supply device. Furthermore, the laser drying apparatus may also include conveying equipment and exhaust equipment.

[0026] The rectifier plate is located inside the furnace body, between the electrode composite layer and the laser source. By installing the rectifier plate, the space for supplying hot air can be narrowed, making it easier to supply hot air to the electrode composite layer.

[0027] In the laser drying apparatus disclosed herein, when the distance between the laser source and the electrode composite layer is set as x, and the distance between the rectifier plate and the electrode composite layer is set as y, y / x can be satisfied as ≤ 0.15, 0.14, 0.13, 0.12, 0.10, 0.08, or 0.05. By satisfying the above relationship, the rectification effect of the hot air brought by the rectifier plate is improved, and the drying efficiency is increased. Alternatively, y / x can also be satisfied as ≥ 0.01, 0.02, 0.03, or 0.04.

[0028] Specifically, for example Figure 2 In this way, the electrode composite layer 300 is disposed on the conveyor belt 151 and irradiated with laser. The aforementioned x is the shortest distance in the height direction from the laser irradiation section of the laser source 130 to the electrode composite layer 300. Furthermore, the aforementioned y is the shortest distance in the height direction from the rectifier plate 120 to the electrode composite layer 300.

[0029] The distance x between the laser source and the electrode composite 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, or 2000mm or more, or it can be less than 5000mm, 4000mm or less, or less than 3000mm. It should be noted that the laser source can be located inside or outside the furnace body.

[0030] There is no particular limitation on the distance y between the rectifier plate and the electrode composite layer. It can be appropriately determined by considering factors such as y / x and the thickness of the electrode composite layer. For example, the distance y can be 5mm or more, 10mm or more, 30mm or more, 50mm or more, or 100mm or more, or it can be less than 750mm, less than 500mm, less than 400mm, or less than 300mm.

[0031] There is no particular limitation on the energy density of the laser irradiating the electrode composite layer inside the drying furnace from the laser source; 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.

[0032] Rectifier plate The rectifier plate is configured to allow laser light to pass through. By allowing laser light to pass through, the laser light emitted from the laser source can be directed onto the electrode composite layer without any waste.

[0033] The transmittance of the laser on the rectifier plate, for laser light irradiated from the aforementioned laser source, can be 95.0% or higher. Furthermore, the aforementioned transmittance can be 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, or it can be 100.0% or lower, or 99.9% or lower.

[0034] 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 by spectrophotometry using a UV-Vis-NIR spectrophotometer (manufactured by Shimadzu Corporation, SolidSpec-3700DUV).

[0035] The material of the rectifier plate is not particularly limited as long as it is laser-transmittable, and can be a material with a heat resistance temperature above the hot air temperature. Examples of materials for the rectifier plate include glass, acrylic (PMMA), polycarbonate (PC), and polyetheretherketone (PEEK).

[0036] Glass can be, for example, quartz glass, soda-lime glass, lead glass, borosilicate glass, alkali glass, etc.

[0037] The size of the rectifier plate is not particularly limited; it can be a size that facilitates the supply of hot air to the electrode composite layer, and can be appropriately determined based on the size of the furnace body and the location of the hot air supply nozzles. For example, Figure 1 The length of the rectifier plate 120 in the conveying direction can be more than 30%, 50%, 70%, or 90% of the length in the width direction of the furnace body, or less than 100% or 95%. Furthermore, the length of the rectifier plate 120 in the width direction (orthogonal to the conveying and height directions) can be more than 30%, 50%, 70%, or 90% of the length in the width direction of the furnace body, or less than 100% or 95%.

[0038] There is no particular limitation on the thickness of the rectifier plate, which can be determined appropriately based on the material of the laser transmittance protection plate. The thickness of the rectifier plate can be, for example, 1mm or more, 3mm or more, 5mm or more, 7mm or more, or 10mm or more, or less than 30mm, 25mm or less, 20mm or less, or 15mm or less.

[0039] The rectifier plate can be tilted from the furnace inlet towards the outlet, getting closer to the electrode composite layer, or from the furnace outlet towards the inlet, getting closer to the electrode composite layer.

[0040] A rectifier plate can be made up of a single plate or by joining multiple plates together.

[0041] There are no particular restrictions on how the rectifier is held; for example, it can be suspended or supported.

[0042] <Furnace Body> The furnace body may be equipped with a laser-transmitting protective plate. In this case, at least a portion of the external casing of the furnace body may be a laser-transmitting protective plate. By having a laser-transmitting protective plate, even if the laser source is located outside the furnace body, the laser can still be irradiated into the interior of the furnace body 110 through the laser-transmitting protective plate.

[0043] Specifically, for example Figure 3 In this way, the furnace body 110 has an outer substrate 111 and a laser transmittance protection plate 112, and the laser source 130 is disposed outside the furnace body 110. Even if the inside of the furnace body 110 is at a high temperature, its heat will not be transferred to the laser source, thus reducing the risk of laser source failure.

[0044] The laser transmittance protection plate can be positioned such that the laser emitted from the laser source located outside the furnace body can be transmitted through the laser transmittance protection plate into the furnace body without leakage.

[0045] There are no particular restrictions on the material of the furnace body's outer substrate; for example, it can be steel, stainless steel, aluminum, etc. The furnace body can undergo surface treatments such as galvanizing and powder coating.

[0046] There are no particular limitations on the size of the furnace body; it can be determined appropriately, taking into account factors such as the size of the electrode composite layer. Furthermore, the furnace body may have openings for loading and unloading the electrode composite layer using conveying equipment.

[0047] (Laser transmittance protection plate) The laser transmittance of the laser transmittance protection plate can be above 95.0%, above 96.0%, above 97.0%, above 98.0%, above 99.0%, above 99.5%, or above 99.8%, or it can be below 100.0% or below 99.9%.

[0048] 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 by spectrophotometry using a UV-Vis-NIR spectrophotometer (manufactured by Shimadzu Corporation, SolidSpec-3700DUV).

[0049] The thermal conductivity of the laser transmittance protection plate 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 protected from the temperature inside the furnace.

[0050] Thermal conductivity can be measured using the heat flow meter method according to the ASTM-E-1530 standard.

[0051] The laser transmittance shield can be made of glass. For more information on glass, please refer to the section on rectifiers mentioned above.

[0052] Laser-transmitting protective panels can be made of multi-layered glass. Because it is multi-layered glass, its heat insulation performance is improved. Multi-layered glass can be a structure in which air, argon, krypton, or other gases are sealed between multiple panes of glass.

[0053] There is no particular limitation on the thickness of the laser transmittance protection plate, which can be determined appropriately based on the material of the laser transmittance protection plate. For example, the thickness of the laser transmittance protection plate can be 1mm or more, 3mm or more, 5mm or more, 7mm or more, or 10mm or more, or it can be less than 30mm, less than 25mm, less than 20mm or less, or less than 15mm.

[0054] There is no particular limitation on the size of the laser permeability protection plate; it can be any size that allows the laser emitted from the laser source to pass through into the furnace body without leakage.

[0055] <Laser source> The laser source irradiates the electrode composite layer via a rectifier plate. Because the rectifier plate has high laser transmittance, the light energy emitted from the laser source can be supplied to the electrode composite layer without waste. Furthermore, when the furnace body has a laser transmittance protection plate, the laser source can irradiate the electrode composite layer via both the protection plate and the rectifier plate. Therefore, even if the laser source is located outside the furnace body, it can still irradiate the electrode composite layer.

[0056] There are no particular limitations on the type of laser source; for example, it can be a Yb fiber laser, a YAG laser, a carbon dioxide laser, etc. The wavelength of the laser can be 0.5μm or higher, 0.6μm or higher, 0.7μm or higher, 0.8μm or higher, or 0.9μm or higher, or it can be below 1.5μm, below 1.4μm, below 1.3μm, below 1.2μm or below 1.1μm.

[0057] 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 it can be below 100kW, below 70kW, or below 50kW.

[0058] 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.

[0059] The shape of the laser irradiation area on the electrode composite layer can be, for example, rectangular. Furthermore, the size of the irradiation area is not particularly limited and can be appropriately determined according to the dimensions of the electrode composite layer. The area of ​​the irradiation area is not particularly limited, for example, it can be 100 cm². 2 Above, 1000cm 2 Above, 5000cm 2 Above or 10000cm 2The above can also be 100,000 cm. 2 Below, 50000cm 2 Below or 30000cm 2 the following.

[0060] Hot air supply equipment The hot air supply equipment supplies hot air between the rectifier plate and the electrode composite layer. By supplying hot air to the electrode composite layer, steam on the surface of the electrode composite layer can be removed, thereby improving drying efficiency.

[0061] The temperature of the hot air supplied from the hot air supply equipment can be above 100℃, above 120℃, above 150℃, above 200℃, above 250℃, or above 300℃, or below 500℃, below 450℃, below 400℃, or below 350℃.

[0062] There are no particular limitations on the hot air supply equipment. For example, it can be a device that uses a blower to supply air heated by gas combustion, petroleum combustion, electric heating, etc., to the electrode composite layer through air ducts and nozzles. From the viewpoint of drying the electrode composite layer, the hot air is preferably low in humidity.

[0063] There is no particular limitation on the direction of hot air supply. For example, when the electrode composite layer is conveyed inside the furnace, it can be in the opposite direction to the conveying direction. In addition, multiple air nozzles can be configured, each with a different supply direction.

[0064] 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. When the wind speed is high, the drying efficiency of the electrode composite layer increases. In addition, 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.

[0065] <Conveying Equipment> There are no particular limitations on the conveying equipment; for example, it can be a roller conveyor, a belt conveyor, etc. The electrode composite layer can be arranged on the conveying path and transported into the furnace body and out of the furnace body.

[0066] The electrode composite 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 considering factors such as the output of the laser source and the energy required for drying the electrode composite 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 it can be less than 3.0 m / s, less than 2.5 m / s, or less than 2.0 m / s.

[0067] The conveying equipment can be connected to other devices such as the coating device for the electrode composite layer and the winding device for the electrode stack.

[0068] <Exhaust Equipment> Laser drying equipment can be equipped with an exhaust system. This system allows for the recovery of steam generated from the electrode composite layer, improving drying efficiency. It should be noted that the steam includes water vapor and other gases.

[0069] Exhaust equipment, for example, can draw steam from the exhaust port using an exhaust fan and discharge the steam to the outside of the furnace via an exhaust pipe. The output of the exhaust fan, the size of the exhaust port, and the exhaust pipe can be appropriately determined taking into account factors such as the amount of steam generated.

[0070] From the viewpoint of improving drying efficiency, the exhaust port is preferably located on the upper part of the electrode composite layer and in a position that does not obstruct laser irradiation. The distance between the exhaust port and the electrode composite layer can be sufficient to draw in steam. The number of exhaust ports is not particularly limited.

[0071] Manufacturing Method of Electrode Laminates A method for manufacturing an electrode laminate using the laser drying apparatus disclosed herein includes the following steps: irradiating an electrode composite layer coated on a current collector layer with a laser; and supplying hot air into the furnace body.

[0072] According to this disclosure, a method for manufacturing an electrode laminate with high drying efficiency can be provided.

[0073] 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 above description of the laser drying apparatus.

[0074] The method disclosed herein includes irradiating an electrode composite layer coated on a current collector layer with a laser. Regarding the electrode composite layer and the laser, refer to the above description of the laser drying apparatus. By irradiating the electrode composite layer with a laser, the dispersion medium contained in the electrode composite layer evaporates, forming an electrode active material layer.

[0075] The dispersion medium contained in the electrode composite 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 (such as diisobutyl ketone) and ester solvents (such as butyl butyrate).

[0076] The content of the aforementioned dispersion medium is not particularly limited. For example, it can be an amount in which the solid component ratio of the electrode composite layer is 30% or more, 35% or more, 40% or more, 45% or more, or 50% or more, or an amount in which the solid component ratio is less than 80%, 75% or less, 70% or less, 65% or less, or 60% or less.

[0077] There are no particular limitations on the coating method for the electrode composite layer. It can be blade coating, die coating, gravure coating, spray coating, electrostatic coating, bar coating, etc.

[0078] There is no particular limitation on the laser irradiation time; for example, irradiation can continue until the electrode composite layer reaches the deceleration drying period. 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.

[0079] The method disclosed herein includes supplying hot air into the furnace body. For details regarding the furnace body and the supply of hot air, please refer to the above description of the laser drying apparatus.

[0080] <Electrode stack> 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. In addition, the electrode stack can be a bipolar electrode stack having both a positive electrode active material layer and a negative electrode active material layer.

[0081] (Electrode active material layer) 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 contain binders, solid electrolytes, and conductive additives, etc., as needed. 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, and conductive additives in the electrode active material layer can be appropriately determined according to the target battery performance.

[0082] The material used for the positive electrode active material is only required to be able to absorb and release lithium ions; there are no particular limitations. 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:LiCo). 1 / 3 Ni 1 / 3 Mn 1 / 3 O2), lithium nickel cobalt aluminum oxide (LiNi) 0.8 (CoAl) 0.2 O2), by Li 1+x Mn 2-x-y M y O4 (where M is one or more metallic elements selected from Al, Mg, Co, Fe, Ni, and Zn) indicates the composition of Li-Mn spinel with heteroelemental substitution, but is not limited to these.

[0083] The shape of the positive electrode active material can be any common shape used in batteries and is not particularly limited. For example, the positive electrode active material can be granular. 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... 50 For example, the particle size can be above 1 nm, above 5 nm, or above 10 nm, or below 500 μm, below 100 μm, below 50 μm, or below 30 μm. It should be noted that 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.

[0084] As the negative electrode active material, various materials with a charge / discharge potential lower than the positive electrode active material disclosed herein can be used, where the potential for absorbing and releasing lithium ions (charge / discharge potential) is lower. The material of the negative electrode active material is not particularly limited; it can be metallic lithium or any material capable of absorbing and releasing metal ions such as lithium ions. Examples of materials capable of absorbing and releasing metal ions such as lithium ions include, for example, alloy-based negative electrode active materials, carbon materials, or lithium titanate (Li4Ti5O). 12 (etc.), but not limited to these.

[0085] There are no particular limitations on alloy-based anode active materials; examples include Si alloy-based anode active materials 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 may 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 may contain metallic elements other than tin, such as Fe, Co, Sb, Bi, Pb, Ni, Cu, Zn, Ge, In, Ti, and Si.

[0086] There are no particular limitations on carbon materials; examples include hard carbon, soft carbon, and graphite.

[0087] There are no particular limitations on the shape of the negative electrode active material; it can be any shape commonly used as a negative electrode active material in a battery. For example, the negative electrode active material can be granular or sheet-like.

[0088] 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 adhesive can be used alone, or two or more can be used in combination.

[0089] There are no particular limitations on the materials used for solid electrolytes; for example, they can be sulfide solid electrolytes, oxide solid electrolytes, or polymer electrolytes.

[0090] 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.

[0091] 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), etc.; or combinations thereof, but not limited to these.

[0092] Sulfide solid electrolytes and oxide solid electrolytes can be glass or crystallized glass (glass ceramics).

[0093] Examples of polymer electrolytes include polyethylene oxide (PEO), polypropylene oxide (PPO), and their copolymers, but are not limited to these.

[0094] The conductive additive is not particularly limited. 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). The conductive additive can be in particulate or fibrous form, and its size is not particularly limited. The conductive additive is not particularly limited; only one type can be used, or two or more types can be used in combination.

[0095] (Current collector layer) The material of the current collector layer is not particularly limited, and common materials used as electrode conductors in a battery can be appropriately used. Examples of materials for the current collector layer include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, and stainless steel, but are not limited to these. Furthermore, the current collector layer can be a metal foil, or a structure formed by depositing or vapor-depositing the aforementioned metals onto a substrate.

[0096] 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.

[0097] There is no particular limitation on the thickness of the current collector layer; it can be 0.1 μm or more, or 1 μm or more, or less than 1 mm or less than 100 μm.

Example

[0098] The present invention will be specifically described through examples and comparative examples, but the present invention is not limited to these examples.

[0099] Preparation of Laser Drying Equipment Prepared for Figure 1 Laser drying apparatuses with the same structure and with the distance y between the rectifier plate and the electrode composite layer adjusted according to Table 1 were used as Examples 1 to 5. Furthermore, the distance x between the laser source and the electrode composite layer was 1500 mm. In addition, a laser drying apparatus identical to Examples 1 to 5 except for the absence of a rectifier plate was prepared as Comparative Example 1.

[0100] The rectifier plate is made of quartz glass, and the transmittance of the laser emitted from the 20kW laser source at a wavelength of 970nm is 99.8%. The laser transmittance was measured by spectrophotometry using a UV-Vis-NIR spectrophotometer (manufactured by Shimadzu Corporation, SolidSpec-3700DUV).

[0101] The area of ​​the rectifier plate is 90% of the bottom area of ​​the furnace body (length in the conveying direction × length in the width direction), and it is positioned so that the hot air supplied from the air supply nozzle will not leak out to the side in the height direction of the rectifier plate.

[0102] The temperature of the hot air supplied from the hot air supply equipment is 120℃.

[0103] Evaluation of the drying efficiency of electrode composite layers <Preparation of Electrode Composite Layer> Lithium cobalt oxide (LiCoO2) as the electrode active material and styrene-butadiene copolymer (SBR) as the binder were weighed at a mass ratio of 97.5:2.5 and mixed with ion-exchanged water at a solid content ratio of 55% to prepare the electrode composite layer. The weight per unit area of ​​the electrode composite layer was 35 mg / cm³. 2 .

[0104] <Evaluation of drying time> The electrode composite layer was coated with an aluminum foil serving as a current collector layer to a thickness of 400 μm, and then placed into the laser drying apparatus of Examples 1 to 5, where the area including the center of the electrode composite layer was irradiated with laser.

[0105] The temperature of the center portion of the electrode composite layer was continuously measured using a radiation thermometer, and the drying time was defined as the point at which the center portion of the electrode composite layer entered the deceleration drying stage. The drying times in the laser drying apparatus of Examples 1 to 5 are shown in Table 1.

[0106] Table 1

[0107] As can be seen from Examples 1 to 5 and Comparative Example 1 in Table 1, by arranging a rectifier plate between the electrode composite layer and the laser source inside the furnace, hot air can be easily supplied to the electrode composite layer, and the drying time is shortened.

[0108] Furthermore, as can be seen from Examples 1 to 5 in Table 1, by reducing x / y, hot air is more easily supplied to the electrode composite layer, and the drying time is further shortened. Explanation of reference numerals in the attached figures

[0109] 100 Laser Drying Equipment 110 Furnace Body 111 Exterior substrate 112 Laser Transmittance Protection Plate 120 rectifier board 130 laser source 140 Hot air supply equipment 141 Hot Air Generator 142 Gas supply pipeline 143 Air supply nozzle 150 Conveying Equipment 151 Conveyor Belt 152 Conveyor Rollers 160 Exhaust Equipment 200 laser 300 electrode composite layer.

Claims

1. A laser drying apparatus for drying electrode composite layers, The laser drying device includes a furnace body, a rectifier plate, a laser source, and a hot air supply system. The rectifier plate is disposed inside the furnace body, between the electrode composite layer and the laser source, and is configured to allow laser light to pass through. The laser source irradiates the electrode composite layer with laser light via the rectifier plate, and The hot air supply device supplies hot air between the rectifier plate and the electrode composite layer.

2. The laser drying apparatus according to claim 1, wherein, The furnace body is equipped with a laser-transmittance protection plate, and The laser source irradiates the electrode composite layer with laser light through the laser transmittance protection plate and the rectifier plate.

3. The laser drying apparatus according to claim 1 or 2, wherein, When the distance between the laser source and the electrode composite layer is set as x, and the distance between the rectifier plate and the electrode composite layer is set as y, the following relationship is satisfied: y / x≤0.

15.

4. The laser drying apparatus according to claim 1 or 2, wherein, For laser light irradiated from the laser source, the transmittance of the laser light from the rectifier plate is above 95.0%.

5. A method for manufacturing an electrode stack, using the laser drying apparatus according to claim 1 or 2, the manufacturing method comprising the following steps: Irradiate the electrode composite layer coated on the current collector layer with a laser; and Hot air is supplied into the furnace body.

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