System for drying electrodes and method for drying electrodes

Abstract

The present invention relates to a system for drying an electrode, the system comprising: a drying unit drying an electrode moving on a transport line; a thermal imaging camera photographing a surface of the electrode in real time; a calculation unit storing an image photographed by the thermal imaging camera and generating temperature distribution data in a width direction of the electrode based on the image; and an output unit outputting the image and the temperature distribution data in the width direction of the electrode.

Description

Technical Field

[0001] Cross-reference to related applications

[0002] This application claims priority based on Korean Patent Application No. 10-2020-0167207, filed on December 3, 2020, the entire contents of which are incorporated herein by reference.

[0003] The present invention relates to a system and method for drying electrodes, and more particularly, to a system and method for drying electrodes using a thermal imaging camera. Background Technology

[0004] Recently, rechargeable and discharging secondary batteries have been widely used as energy sources for wireless mobile devices. Furthermore, secondary batteries are attracting attention as an energy source for electric vehicles, hybrid electric vehicles, and other applications proposed as a solution to air pollution from existing gasoline and diesel vehicles that use fossil fuels. Therefore, due to the advantages of secondary batteries, their applications are currently very diverse, and it is expected that they will be used in many fields and products in the future.

[0005] These secondary batteries can be classified into lithium-ion batteries, lithium-ion polymer batteries, and lithium polymer batteries based on the composition of their electrodes and electrolytes. Among them, the use of lithium-ion polymer batteries, which have a low possibility of electrolyte leakage and are easy to manufacture, is increasing. Generally, depending on the shape of the battery casing, secondary batteries can be divided into cylindrical batteries and prismatic batteries, where the electrode assembly is embedded in a cylindrical or rectangular metal can, and pouch batteries, where the electrode assembly is embedded in a pouch-shaped casing made of aluminum laminate. The electrode assembly built into the battery casing consists of a positive electrode, a negative electrode, and a separator inserted between the positive and negative electrodes, and is a power generation element capable of charging and discharging. The electrode assembly is divided into a jelly roll type, in which long, sheet-like positive and negative electrodes coated with active material are wound together with a separator inserted between them, and a stacked type, in which multiple positive and negative electrodes of predetermined size are sequentially stacked with separators inserted between them.

[0006] The positive electrode and the negative electrode are formed by coating a positive electrode slurry containing a positive electrode active material and a negative electrode slurry containing a negative electrode active material onto a positive electrode current collector and a negative electrode current collector, respectively, and then drying and rolling them.

[0007] To achieve high-power batteries, increasing the amount of active material loaded onto the current collector can be employed, but it is crucial to improve the quality of the electrode itself and prevent defects. To improve electrode quality, the drying process for the electrode sheet coated with the active material layer is essential. Uniform drying of the electrode surface prevents deviations or defects between products. Therefore, measuring the electrode surface temperature can be used to evaluate the drying quality of the electrode.

[0008] Typically, a thermometer or infrared thermometer is used to measure the surface temperature of such electrodes. However, simply measuring the surface temperature of the electrode is insufficient to evaluate the drying quality of the electrode. For example, even if some areas of the electrode are completely dry, other areas may still be undried. Although multiple thermometers are arranged to improve this, it is impossible to measure the areas where thermometers are not arranged, and the drying quality in the width direction of the electrode cannot be visually determined.

[0009] Therefore, a technique is needed that can easily determine the drying quality of the electrodes without affecting the processing efficiency. Summary of the Invention

[0010] Technical issues

[0011] It is believed that the present invention solves at least some of the problems mentioned above. For example, one aspect of the present invention provides an electrode drying system and method capable of evaluating the drying quality of electrodes in real time.

[0012] Technical solution

[0013] A system for drying electrodes according to one embodiment of the present invention includes: a drying unit for drying electrodes moving on a transmission line; a thermal imaging camera for capturing images of the electrode surface in real time; a computing unit for storing images captured by the thermal imaging camera and generating temperature distribution data in the width direction of the electrode based on the images; and an output unit for outputting the images and the temperature distribution data in the width direction of the electrode.

[0014] In one specific embodiment, the thermal imaging camera can continuously or sequentially capture images of the surface of the electrode, and the computing unit can store the images in predetermined frames or time units.

[0015] In one specific embodiment, the computing unit can calculate from the image the temperature distribution change in the width direction of the electrode and the change of the average temperature in the width direction of the electrode over time.

[0016] In one specific embodiment, the thermal imaging camera may be positioned at the outlet of the drying unit.

[0017] In another embodiment, the thermal imaging camera may be positioned along the movement path of the electrodes in the drying unit.

[0018] At this time, the drying unit is divided into multiple drying zones, and the thermal imaging camera can be positioned between the drying zones.

[0019] In one specific embodiment, the electrode drying system according to the present invention may further include a clamp that fixes the thermal imaging camera to form a predetermined angle with the electrode.

[0020] In another embodiment, the electrode drying system according to the invention may further include a controller that evaluates the drying quality of the electrode based on the temperature distribution data and resets the drying conditions of the electrode by reflecting the results of the evaluation.

[0021] Furthermore, the present invention provides a method for drying an electrode. The electrode drying method includes: inserting an electrode into a drying unit and drying the electrode in the drying unit; photographing the surface of the electrode with a thermal imaging camera; and generating temperature distribution data in the width direction of the electrode based on the image acquired by the thermal imaging camera.

[0022] In one specific embodiment, the temperature distribution data in the width direction of the electrode may include the temperature distribution variation in the width direction of the electrode and the average temperature variation in the width direction of the electrode over time.

[0023] In one specific embodiment, the thermal imaging camera takes pictures of the electrode surface during (a) the electrode drying process, (b) the electrode drying process, or (c) the electrode drying process and the electrode drying process.

[0024] In one specific embodiment, the electrode drying method according to the present invention may further include evaluating the drying quality of the electrode based on temperature distribution data in the width direction of the electrode.

[0025] In one specific embodiment, if the temperature difference between the highest and lowest temperatures in the temperature distribution data in the width direction exceeds a preset reference value, it can be determined that the drying state of the electrode is defective.

[0026] In one specific embodiment, when the average temperature over time in the width direction of the electrode in the temperature distribution data is less than a preset reference value, it can be determined that the drying state of the electrode is defective.

[0027] Furthermore, the electrode drying method according to the present invention may also include resetting the drying conditions based on the results of the evaluation.

[0028] Beneficial effects

[0029] According to the present invention, temperature distribution data along the width of the electrode can be ensured by using a thermal imaging camera. This allows for easy evaluation of the drying quality of the electrode without affecting the efficiency of the manufacturing process. Attached Figure Description

[0030] Figure 1 This is a block diagram illustrating the structure of an electrode drying system according to an embodiment of the present invention.

[0031] Figure 2 and Figure 3 This is a schematic diagram illustrating an electrode drying process according to an embodiment of the present invention.

[0032] Figure 4 It is a photograph showing the electrodes in a dry state, which was obtained by taking pictures of the electrodes using a thermal imaging camera.

[0033] Figure 5 (a)-(b) are graphs showing the temperature distribution data along the width of the electrode based on images obtained using a thermal imaging camera.

[0034] Figure 6 This is a schematic diagram illustrating an electrode drying process according to another embodiment of the present invention.

[0035] Figure 7 This is a block diagram illustrating the structure of an electrode drying system according to another embodiment of the present invention.

[0036] Figure 8 This is a flowchart illustrating the procedure of the electrode drying method according to the present invention. Detailed Implementation

[0037] The invention will be described in detail below with reference to the accompanying drawings. The terms and words used in the specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventors may appropriately define the concepts of the terms in order to best describe the invention. The terms and words should be interpreted as having meanings and concepts consistent with the technical spirit of the invention.

[0038] In this application, it should be understood that terms such as "comprising" or "having" are intended to indicate the features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, and they do not preclude the possibility of the presence or addition of one or more other features or quantities, steps, operations, components, parts, or combinations thereof. Furthermore, when a part such as a layer, membrane, region, plate, etc., is referred to as being "on" another part, this includes not only the case where the part is "directly" on the other part, but also the case where another part may be inserted therein. On the other hand, when a part such as a layer, membrane, region, plate, etc., is referred to as being "below" another part, this includes not only the case where the part is "directly" below the other part, but also the case where another part may be inserted therein. Additionally, the term "on" in this application can include housings disposed at the bottom and top.

[0039] Furthermore, in this invention, "width direction" refers to the direction represented by the width of the electrode (TD direction, x-axis direction) and the direction perpendicular to the transmission direction of the electrode on the plane formed by the electrode (y-axis direction).

[0040] The invention will now be described in detail with reference to the accompanying drawings.

[0041] Figure 1 This is a block diagram illustrating the structure of an electrode drying system according to an embodiment of the present invention.

[0042] refer to Figure 1 An electrode drying system 100 according to one embodiment of the present invention includes: a drying unit 120 for drying an electrode moving on a transmission line; a thermal imaging camera 130 for capturing images of the electrode surface in real time; a computing unit 140 for storing images captured by the thermal imaging camera and generating temperature distribution data in the width direction of the electrode based on the images; and an output unit 150 for outputting the images and the temperature distribution data in the width direction of the electrode.

[0043] As mentioned above, the surface temperature of the electrode is typically measured directly using a measuring device such as a thermometer to evaluate the drying quality of the electrode. However, simply measuring the surface temperature of the electrode is insufficient to evaluate the drying quality of the electrode.

[0044] According to the present invention, temperature distribution data in the width direction of the electrode can be ensured by using a thermal imaging camera. This allows for easy evaluation of the drying quality of the electrode without affecting the efficiency of the manufacturing process. That is, since the drying quality of the moving electrode can be evaluated in real time, defects can be detected in advance, and process losses can be reduced by addressing potential defects.

[0045] Figure 2 and Figure 3 This is a schematic diagram illustrating an electrode drying process according to an embodiment of the present invention.

[0046] Combination Figure 1 refer to Figure 2 and Figure 3 The electrode drying system 100 according to the present invention includes a drying unit 120 for drying electrodes.

[0047] The drying unit 120 can be made in the form of an oven. Specifically, the drying unit 120 provides space for the drying electrode 110, which is in the shape of a chamber. In this invention, the manufacturing and drying processes of the electrode are performed in a roll-to-roll manner. The electrode 110 can be inserted into the drying unit 120 along a predetermined transmission line and can be dried while moving within the drying unit 120.

[0048] The drying unit 120 may include a hot air nozzle or an infrared heater as a heat source 121 to dry the electrodes therein. The hot air nozzle or infrared heater may be arranged at predetermined intervals along the transmission direction (MD direction) of the electrodes and apply hot air or infrared radiation in a direction perpendicular to the electrodes.

[0049] Furthermore, electrode 110 can have a structure in which an electrode active material layer 112 is formed by applying an electrode slurry containing electrode active material onto current collector 111 and drying and rolling the electrode slurry. The process of applying the electrode slurry onto the current collector can be performed by a coating die 101. The coating die 101 can have a general slit die shape, and its details are known to those skilled in the art, so a detailed description will be omitted.

[0050] The current collector can be either a positive or negative electrode current collector, and the electrode active material can be either a positive or negative electrode active material. Furthermore, in addition to the electrode active material, the electrode paste may also include conductive materials and binders.

[0051] Furthermore, the electrode can be either a positive or a negative electrode. More specifically, it can be a negative electrode at the frequency of desorption of the active material.

[0052] In this invention, the thickness of the positive electrode current collector is typically 3–500 μm. There are no particular limitations on the positive electrode current collector, as long as it has high conductivity without causing chemical changes in the battery. Examples of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon or aluminum, or stainless steel with a surface treated with carbon, nickel, titanium, silver, or the like. The current collector may have slight irregularities on its surface to increase the adhesion of the positive electrode active material, and can take various forms, such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0053] The thickness of the negative electrode current collector sheet is typically 3–500 μm. There are no particular limitations on the negative electrode current collector, as long as it is conductive without causing chemical changes in the battery. Examples include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, or stainless steel or aluminum-cadmium alloys whose surfaces have been treated with carbon, nickel, titanium, silver, etc. Furthermore, similar to the positive electrode current collector, a fine surface roughness can be formed to improve the adhesion of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, meshes, porous bodies, foams, and nonwoven fabrics.

[0054] In this invention, the positive electrode active material is a substance capable of inducing an electrochemical reaction and a lithium transition metal oxide, and contains two or more transition metals. Examples include: layered compounds, such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2) substituted with one or more transition metals; lithium manganese oxide substituted with one or more transition metals; and compounds with the chemical formula LiNi... 1-y M y Lithium nickel oxide represented by O2 (where M = Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn or Ga and containing at least one of the above elements, 0.01≤y≤0.7); Li 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e Lithium-nickel-cobalt-manganese composite oxides, such as Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li 1+z Ni 0.4 Mn 0.4 Co 0.2 O2, etc. (where -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, b+c+d<1, M=Al, Mg, Cr, Ti, Si or Y, and A=F, P or Cl); from the chemical formula Li 1+x M 1-y M' y PO 4-z X z (where M = transition metal, preferably Fe, Mn, Co or Ni, M' = Al, Mg or Ti, X = F, S or N, and -0.5≤x≤0.5, 0≤y≤0.5, 0≤z≤0.1) represents olivine-based lithium metal phosphate.

[0055] Examples of the negative electrode active material include: carbon, such as non-graphitized carbon and graphitic carbon; metal composite oxides, such as Li x Fe2O3(0 ≤ x ≤ 1), Li x WO2(0 ≤ x ≤ 1), Sn x Me 1-x Me’ y O z (Me: Mn, Fe, Pb, Ge; Me': Al, B, P, Si, Groups 1, 2 and 3 of the periodic table, halogens; 0 < x ≤ 1; 1 ≤ y ≤ 3; 1 ≤ z ≤ 8); lithium alloys; silicon alloys; tin alloys; metal oxides, such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 and Bi2O5; conductive polymers, such as polyacetylene; and Li-Co-Ni-based materials.

[0056] Based on the total weight of the mixture containing the positive electrode active material, the addition amount of the conductive material is usually 1 - 30% by weight. Such conductive materials are not particularly limited as long as they have conductivity without causing chemical changes in the battery, and examples thereof may include graphite, such as natural graphite and artificial graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black and summer black; conductive fibers, such as carbon fibers and metal fibers; metal powders, such as carbon fluoride, aluminum and nickel powders; conductive whiskers, such as zinc oxide and potassium titanate; conductive metal oxides, such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0057] Based on the total weight of the mixture containing the positive electrode active material, the binder is added in an amount of 1 - 30% by weight ratio as a component to assist in bonding between the auxiliary active material and the conductive material and bonding to the current collector. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene - propylene - diene terpolymer (EPDM), sulfonated EPDM, styrene - butadiene rubber, fluororubber, various copolymers, etc.

[0058] Simultaneously, this electrode slurry can be prepared by dissolving the electrode active material, conductive material, and binder in a solvent. The type of solvent is not particularly limited as long as it can disperse the electrode active material, and any aqueous or non-aqueous solvent can be used. For example, the solvent can be a solvent commonly used in the art, such as dimethyl sulfoxide (DMSO), isopropanol, N-methylpyrrolidone (NMP), acetone, or water, and mixtures of one or more of these can be used. The amount of solvent used is not particularly limited, as long as it allows the slurry to be adjusted to a suitable viscosity, taking into account coating thickness, yield, and slurry processability.

[0059] As the manufactured electrode 110 moves within the space of the drying unit 120, the solvent evaporates. At this time, the electrode drying system 100 according to the present invention may include a temperature measuring device for real-time imaging of the surface of the electrode 110 to evaluate the degree of dryness of the electrode 110.

[0060] In this invention, a thermal imaging camera 130 can be used as a temperature measuring device. Unlike a conventional thermometer, the thermal imaging camera 130 can measure the temperature of the entire area of ​​the object being measured, as well as a single point on the object, by viewing the temperature distribution of the entire object as a single image.

[0061] This helps in evaluating the drying quality of the electrodes. This is because it's impossible to dry the entire area of ​​the electrode uniformly during the drying process. That is, there may be deviations in drying quality across different areas of the electrode. For example, based on the width of the electrode, the drying speed at the edges becomes faster than at the center due to the superposition of hot air. Especially when drying electrodes with a wider width, the deviation in drying quality at specific points or areas becomes larger, leading to product defects.

[0062] Therefore, using a thermal imaging camera makes it easier to identify areas with lower dryness compared to using a thermometer.

[0063] Figure 4 The image shows a photograph of the electrode in its dry state, obtained by taking a picture of the electrode using a thermal imaging camera. Figure 5 (a) and (b) are graphs showing the temperature distribution data in the width direction of the electrode based on images obtained by taking pictures of the electrode using a thermal imaging camera.

[0064] refer to Figure 2 and Figure 4The thermal imaging camera 130 continuously or sequentially images the surface of the electrode, which is the object of measurement, thereby detecting the surface temperature distribution of the electrode. If the thermal imaging camera 130 is used to image the surface of the electrode, the temperature distribution by area can be confirmed by color. This allows for the simultaneous measurement of the temperature at two or more points on the object being measured. Furthermore, since the temperature between points can be continuously measured using the thermal imaging camera 130, the temperature distribution over the entire area of ​​the object being measured can be visually or qualitatively assessed. (Reference) Figure 3 Areas with lower drier conditions are darker than areas with higher drier conditions. In other words, using a thermal imaging camera to photograph the electrode allows for a visual inspection of the temperature distribution and dryness across its width; if the entire surface of the electrode is bright without any dark areas, it can be determined that the electrode drying process is complete.

[0065] In addition, refer to Figure 1 and Figure 2 The electrode drying system 100 according to the present invention includes a computing unit 140, which stores images captured by the thermal imaging camera 130 and generates temperature distribution data in the electrode width direction based on the images.

[0066] By photographing the surface of electrode 110 using thermal imaging camera 130, an image displaying color differences according to temperature can be obtained. This allows for qualitative measurement of the temperature distribution on the electrode surface, particularly the temperature distribution along the width of the electrode, but it is difficult to measure the specific temperature distribution on the electrode surface and evaluate the degree of dryness accordingly. Furthermore, when using only images captured by thermal imaging camera 130, evaluation errors may exist depending on the observer's viewpoint, and there are limitations to automated drying quality evaluation. The computing unit 140 can improve the accuracy of drying quality evaluation by converting the images captured by thermal imaging camera 130 into specific temperature values ​​and generating temperature distribution data according to the width of the electrode, and allows for rapid data processing and equipment automation.

[0067] Specifically, the computing unit 140 stores images captured by the thermal imaging camera 130 in predetermined frames or time units, and converts the images into specific temperature values, thereby generating temperature distribution data according to the width direction of the electrodes. For example, the computing unit 140 can obtain data from... Figure 5 The image shown calculates the temperature distribution variation along the width of the electrode and the average temperature along the width of the electrode over time.

[0068] Figure 5 (a) shows the change of the average temperature along the width of the electrode surface over time, and specifically shows the average value of the temperature distribution along the width of the electrode from a predetermined point over time. Figure 5In (a), the horizontal axis represents the measurement time, and the vertical axis represents the average temperature along the electrode width. From Figure 5 As can be seen in (a), the average temperature in the width direction of the electrode gradually increases as drying proceeds.

[0069] Figure 5 (b) shows the temperature distribution variation along the width of the electrode. Figure 5 In (b), the horizontal axis represents the relative positions of each point along the width of the electrode, and the vertical axis represents the temperature at each point. See also Figure 5 (b) The temperature of the two edge portions of the electrode in the width direction is higher than that of the center portion, indicating that the drying rate of the two edge portions of the electrode in the width direction is higher than that of the center portion.

[0070] The calculation unit 140 can use known methods to convert images captured by the thermal imaging camera 130 into specific temperature values. For example, after deriving the correlation of electrode surface temperature based on the electrode color displayed on the thermal image from a database generated based on accumulated thermal image data of the actual surface temperature of the electrode, the correlation can be applied. The temperature distribution data of the electrode in the width direction obtained in this way can be used to evaluate the drying quality of the electrode and adjust the drying conditions.

[0071] Furthermore, the thermal imaging camera 130 can be mounted at a single point and continuously or sequentially photograph the surface of the electrode 110 moving along the transmission line. For this purpose, the electrode drying system according to the invention may further include a clamp that holds the thermal imaging camera at a predetermined angle to the electrode.

[0072] Specifically, such as Figure 2 As shown, the thermal imaging camera 130 can be installed at the outlet of the drying unit 120. That is, the thermal imaging camera 130 can be positioned in the rear region of the drying unit 120 based on the transmission line to photograph the surface of the electrode 110 removed from the drying unit 120, and the calculation unit 140 evaluates the drying quality of the dried electrode.

[0073] Figure 6 This is a schematic diagram illustrating an electrode drying process according to another embodiment of the present invention.

[0074] refer to Figure 6 The electrode drying system 200 according to the present invention includes: a drying unit 120 for drying an electrode 110 moving on a transmission line, and a thermal imaging camera 130 for real-time imaging of the electrode surface. When electrode slurry is applied to a current collector through a coating die 101, an electrode can be manufactured by forming an electrode mixture layer.

[0075] At this time, the thermal imaging camera 130 can be positioned on the movement path of the electrode 110 in the drying unit 120. In this case, the thermal imaging camera 130 can capture images of the surface of the electrode 110 being dried in the drying unit 120, and the computing unit can evaluate the drying quality of the electrode. Therefore, defects in the drying state of the electrode can be identified during the drying process, and poor drying quality of the final manufactured electrode can be prevented. However, this configuration does not preclude the thermal imaging camera from being located at the outlet portion of the drying unit, and the thermal imaging camera can be located both inside the drying unit and at the outlet of the drying unit.

[0076] Furthermore, the drying unit 120 can be divided into multiple drying zones. If the electrode is over-dried or under-dried during the drying process, it is necessary to properly dry the electrode while changing the drying intensity. In this case, by dividing the drying unit 120 into multiple drying zones, the drying conditions can be managed independently for each drying zone. Figure 6 A drying unit 120 divided into two drying zones is shown, and each drying zone is defined as a first drying zone 120a and a second drying zone 120b. In this case, each drying zone 120a or 120b can be a space physically separated by actually installing inner walls between the drying zones, or it can be a space abstractly divided according to the drying conditions carried out in the drying zones.

[0077] Similarly, when the drying unit 120 is divided into multiple drying zones 120a and 120b, the thermal imaging camera can be located between the drying zones 120a and 120b. (Reference) Figure 6 A second thermal imaging camera 130b located in the drying unit 120 can be positioned between the first drying zone 120a and the second drying zone 120b. In this case, interference from heat sources inside the drying unit can be prevented, or the thermal imaging camera can be prevented from obstructing the drying of the electrode. Furthermore, if a drying quality difference is determined by the measurement results of the second thermal imaging camera 130b located between drying zones 120a and 120b, the drying conditions of the second drying zone 120b can be changed to compensate for this. The first thermal imaging camera 130a is located at the outlet of the drying unit 120, thereby allowing measurement of the surface of the dried electrode 110.

[0078] refer to Figure 1 If the thermal imaging camera 130 takes a picture of the electrode surface, and then the computing unit 140 generates temperature distribution data in the width direction of the electrode, the image taken by the thermal imaging camera 130 and the temperature distribution data in the width direction of the electrode generated by the computing unit 140 can be displayed by the output unit 150.

[0079] Figure 7 This is a block diagram illustrating the structure of an electrode drying system according to another embodiment of the present invention.

[0080] refer to Figure 7 The electrode drying system 300 according to the present invention may further include a controller 160, which evaluates the drying quality of the electrode based on the temperature distribution data and resets the drying conditions of the electrode by reflecting the evaluation results. That is, if it is determined that the drying state of the electrode is defective, the controller 160 can change the drying conditions to meet the standards regarding the drying quality of the electrode.

[0081] As described above, the calculation unit 140 can calculate the temperature distribution change in the width direction of the electrode and the change in the average temperature in the width direction of the electrode over time based on the image captured by the thermal imaging camera 130. Based on this, the controller 160 can evaluate the deviation in the degree of dryness in the width direction of the electrode and whether the electrode is dry enough. If the deviation in the degree of dryness in the width direction of the electrode is too large, or the overall degree of dryness is low, it can be determined that the drying state of the electrode is defective. In this case, the controller 160 can change the drying intensity to reduce the deviation in the degree of dryness in the width direction of the electrode or to further dry the electrode. For example, it can change the intensity of the hot air, the temperature of the hot air, the output of the infrared heater, the operating speed of the electrode, etc.

[0082] In addition, the present invention provides an electrode drying method.

[0083] Figure 8 This is a flowchart illustrating the steps of the electrode drying method according to the present invention.

[0084] refer to Figure 8 The electrode drying method includes: inserting the electrode into a drying unit and drying the electrode in the drying unit (S10); taking an image of the surface of the electrode using a thermal imaging camera (S20); and generating temperature distribution data of the electrode in the width direction based on the image acquired by the thermal imaging camera (S30).

[0085] According to the present invention, temperature distribution data in the width direction of the electrode can be ensured by using a thermal imaging camera. This allows for easy evaluation of the drying quality of the electrode without affecting the efficiency of the manufacturing process. That is, since the drying quality of the moving electrode can be evaluated in real time, defects can be detected in advance, and process losses can be reduced by addressing potential defects.

[0086] First, an electrode is manufactured by forming an electrode active material layer containing electrode active material on a current collector. The details of the electrode are the same as described above. If the electrode is inserted, the drying process begins by supplying the electrode to the aforementioned drying unit.

[0087] In this process, the surface of the electrode is photographed using a thermal imaging camera. The photographing of the electrode surface can be performed during (a) the electrode drying process, (b) after the electrode drying process, or (c) during and after the electrode drying process. That is, according to the present invention, the drying quality of the electrode can be effectively evaluated by using a thermal imaging camera to photograph the electrode in real time while it is drying or has already dried.

[0088] If an image is captured using a thermal imaging camera, temperature distribution data along the width of the electrode is derived from the image. This is performed by a computing unit. Specifically, the temperature of the electrode surface can be derived from the colors displayed on the thermal image, and thus the temperature distribution data along the width of the electrode can be derived. The temperature distribution data along the width of the electrode can include the temperature distribution variation along the width of the electrode and the variation of the average temperature along the width of the electrode over time. Details regarding this are the same as described above.

[0089] Furthermore, the electrode drying method according to the present invention may further include evaluating the drying quality of the electrode based on temperature distribution data in the width direction of the electrode (S40). Specifically, in the step of evaluating the drying quality of the electrode, the overall degree of drying of the electrode and the deviation of the degree of drying in the width direction of the electrode can be evaluated. For example, if the temperature difference between the highest and lowest temperatures in the temperature distribution in the width direction exceeds a preset reference value, it indicates that the degree of drying in the width direction is significantly different, and it can be determined that the drying state of the electrode is defective. Further, when the average temperature in the width direction of the electrode is lower than a preset reference value, it indicates that drying is not complete, and it can be determined that the drying state of the electrode is defective.

[0090] Similarly, if the drying quality of the electrode is evaluated, the drying conditions are reset to reflect the evaluation results (S50). The drying conditions of the electrode may be related to the intensity of drying, and some examples of drying conditions include the intensity of hot air, the temperature of hot air, the output of the infrared heater, and the moving speed of the electrode. For example, when it is determined that the electrode is not dry, the intensity of the hot air, the temperature of the hot air, or the output of the infrared heater can be increased, and the moving speed of the electrode can be decreased. Furthermore, when the degree of dryness of the edge portion of the electrode in the width direction is too great compared to the center portion, the intensity of the hot air, the temperature of the hot air, or the output power of the infrared heater at the edge portion can be reduced relative to the center portion. Alternatively, the deviation in the degree of dryness in the width direction can be mitigated by blocking the hot air or infrared radiation applied to the edge portion of the electrode.

[0091] The above description is merely an illustration of the technical concept of the present invention. Those skilled in the art can make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the accompanying drawings disclosed in this invention are not intended to limit the technical concept of the invention, but rather to illustrate it. The scope of the technical concept of the present invention is not limited by these drawings. The scope of protection of this invention should be interpreted by the appended claims, and all technical concepts within their equivalent scope should be interpreted as included within the scope of this invention.

[0092] On the other hand, this specification uses terms indicating directions such as up, down, left, right, front, and back, but it is clear that these terms are only for ease of explanation and may change depending on the position of the object or the observer.

[0093] [Figure Labels]

[0094] 100, 200, 300: Electrode drying system

[0095] 101: Coating Die

[0096] 110: Electrode

[0097] 111: Current collector

[0098] 112: Electrode active material layer

[0099] 120: Drying unit

[0100] 120a: First Dry Zone

[0101] 120b: Second Drying Zone

[0102] 121: Heat source

[0103] 130: Thermal imaging camera

[0104] 130a: First thermal imaging camera

[0105] 130b: Second thermal imaging camera

[0106] 140: Unit of Calculation

[0107] 150: Output Unit

[0108] 160: Controller

Claims

1. A system for drying electrodes, the system comprising: A drying unit that dries electrodes moving on a transmission line; A thermal imaging camera, which captures images of the surface of the electrode in real time; A computing unit that stores images or videos captured by the thermal imaging camera and generates temperature distribution data in the width direction of the electrode based on the images or videos; An output unit that outputs the image or video and temperature distribution data in the width direction of the electrode; and A controller evaluates the drying quality of the electrode based on the temperature distribution data and resets the drying conditions of the electrode based on the evaluation results. The calculation unit calculates the temperature distribution change along the width of the electrode and the change in the average temperature along the width of the electrode over time from the image or video. If the temperature difference between the highest and lowest temperatures in the temperature distribution data along the width direction exceeds a preset reference value, the controller determines that the drying state of the electrode is defective.

2. The system according to claim 1, wherein, The thermal imaging camera continuously or sequentially captures images of the surface of the electrodes, and The computing unit stores the image or video in predetermined frames or time units.

3. The system according to claim 1, wherein, The thermal imaging camera is located at the outlet of the drying unit.

4. The system according to claim 1, wherein, The thermal imaging camera is positioned on the moving path of the electrodes in the drying unit.

5. The system according to claim 4, wherein, The drying unit is divided into multiple drying zones, and The thermal imaging camera is positioned between the plurality of dry zones.

6. The system of claim 1 further includes a clamp that secures the thermal imaging camera at a predetermined angle to the electrode.

7. A method for drying an electrode, the method comprising: The electrode is inserted into the drying unit and dried in the drying unit; The surface of the electrode is photographed using a thermal imaging camera; Temperature distribution data along the width of the electrode is generated based on the images or videos acquired by the thermal imaging camera. The drying quality of the electrode is evaluated based on the temperature distribution data along the width direction of the electrode. as well as The drying conditions are then reset to reflect the results of the evaluation. The temperature distribution data along the width of the electrode includes the temperature distribution variation along the width of the electrode and the change of the average temperature along the width of the electrode over time. If the temperature difference between the highest and lowest temperatures in the temperature distribution data along the width direction exceeds a preset reference value, then the drying state of the electrode is determined to be defective.

8. The method according to claim 7, wherein, The surface of the electrode is photographed using the thermal imaging camera in the following manner: (a) During the drying process of the electrode, (b) After the electrode is dried, or (c) During and after the drying process of the electrode.

9. The method according to claim 7, wherein, When the average temperature over time in the width direction of the electrode in the temperature distribution data is less than a preset reference value, it is determined that the drying state of the electrode is defective.

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