KR20220030751A - System for automatically controlling the drying of electrodes and method for automatically controlling the drying of electrodes - Google Patents

Abstract

The present invention relates to a system for automatically controlling drying of an electrode, including: an oven that provides a space for drying the electrode and has a hot air nozzle and an infrared heater therein; a photographing unit that is placed in the oven and obtains an image or a video by photographing the surface state of the electrode in real time; a measuring unit that converts the image or the video to gray scale and measures a gray value of the converted image; and a control unit that determines the drying level of the electrode from the gray level value from the gray value and automatically controls the drying strength of the electrode.

Description

Electrode drying automatic control system and electrode drying automatic control method

It relates to an automatic electrode drying control system and an automatic electrode drying control method, and more particularly, to an electrode drying automatic control system and an electrode drying automatic control method by measuring a gray value.

Recently, rechargeable batteries capable of charging and discharging have been widely used as energy sources for wireless mobile devices. In addition, the secondary battery is attracting attention as an energy source for electric vehicles, hybrid electric vehicles, etc., which have been proposed as a way to solve air pollution of conventional gasoline vehicles and diesel vehicles using fossil fuels. Accordingly, the types of applications using secondary batteries are diversifying due to the advantages of secondary batteries, and it is expected that secondary batteries will be applied to more fields and products in the future than now.

These secondary batteries are sometimes classified into lithium ion batteries, lithium ion polymer batteries, lithium polymer batteries, etc. depending on the composition of the electrode and electrolyte. is increasing In general, secondary batteries, depending on the shape of the battery case, a cylindrical battery and a prismatic battery in which the electrode assembly is built in a cylindrical or prismatic metal can, and a pouch-type battery in which the electrode assembly is built in a pouch-type case of an aluminum laminate sheet The electrode assembly built into the battery case consists of a positive electrode, a negative electrode, and a separator structure interposed between the positive electrode and the negative electrode, and is a power generating element capable of charging and discharging. It is classified into a jelly-roll type wound with a separator interposed therebetween, and a stack type in which a plurality of positive and negative electrodes of a predetermined size are sequentially stacked with a separator interposed therebetween.

The positive electrode and the negative electrode are formed by applying a positive electrode slurry containing a positive electrode active material and a negative electrode slurry containing a negative electrode active material to a positive electrode current collector and a negative electrode current collector, respectively to form a positive electrode active material layer and a negative electrode active material layer, followed by drying and rolling them do.

At this time, the drying conditions of the electrode affect the quality and physical properties of the electrode, and in particular, the adhesion and surface bonding level of the electrode may vary greatly depending on the deviation of the drying degree in the electrode width direction during drying and the control of the drying completion time. In the past, the initial process conditions were determined in advance and the process conditions were adjusted by drying the electrodes and then evaluating the product dryness and physical properties. In this case, there is a problem in that it is difficult to control the drying of the electrodes in real time.

To this end, there is a method to indirectly evaluate the drying level at each drying time point of the electrode by measuring the solvent exhaust amount or the electrode surface temperature at each drying point of the electrode, but even in this case, the real-time drying degree of the electrode, the deviation of the dryness, and the control of the surface bonding are limited. there is a problem called

Therefore, there is a need to develop a technology for real-time drying control of electrodes that can solve the above problems.

Japanese Patent No. 5831223

The present invention has been devised to solve the above problems, and an object of the present invention is to provide an electrode drying automatic control system and an electrode drying automatic control method capable of automatically controlling the degree of electrode drying in real time.

An electrode drying automatic control system according to the present invention provides a space in which electrodes are dried, and includes an oven having a hot air nozzle and an infrared heater therein; a photographing unit located in the oven and obtaining an image or an image by photographing the surface state of the electrode in real time; a measuring unit that converts the image or image into gray scale and measures a gray value of the converted image; and a control unit that determines the drying level of the electrode from the gray level value and automatically controls the drying intensity of the electrode therefrom.

In a specific example, in the oven, the hot air nozzle and the infrared heater are alternately arranged along the traveling direction of the electrode.

In a specific example, the oven is divided into a plurality of zones, and the photographing unit is located between the zones.

The electrode drying automatic control system according to the present invention further includes a cooling device for cooling the photographing unit.

In a specific example, the gray level value is measured with respect to the width direction of the electrode.

In a specific example, the measurement unit quantifies the drying level for each part of the electrode and the drying time of the electrode from the gray level value.

In a specific example, the controller automatically controls the drying intensity for each part of the electrode according to the drying level.

In one example, the drying strength is controlled through the transfer speed of the electrode, the temperature of the hot air, the flow rate of the hot air and the output control of the infrared heater.

In another example, the electrode drying automatic control system according to the present invention further includes at least one shield positioned between the infrared heater and the electrode.

In a specific example, the control unit controls the area to which the electrode is exposed to hot air or infrared rays by controlling the position of the shielding frame.

In addition, the present invention provides a method for automatically controlling electrode drying, the method comprising: transferring an electrode into an oven as described above; obtaining an image or image by photographing the surface state of the electrode in real time while drying the electrode; measuring a gray level value for the image or image; determining the drying level of the electrode from the gray level value; and automatically controlling the drying strength of the electrode by reflecting the drying level of the electrode.

In a specific example, the gray level value is measured with respect to the width direction of the electrode.

In a specific example, determining the drying level of the electrode includes quantifying the drying level according to each part of the electrode and the drying time of the electrode.

In one example, the step of automatically controlling the drying strength of the electrode includes automatically controlling the transfer speed of the electrode, the temperature of the hot air, the flow rate of the hot air, and the output of the infrared heater.

In another example, the step of automatically controlling the drying intensity of the electrode includes controlling an area of the electrode exposed to hot air or infrared rays.

The present invention obtains an image of the surface of the electrode in real time, and controls the drying intensity of the electrode using the gray value obtained therefrom, so that the degree of drying of the electrode can be automatically controlled in real time.

1 is a block diagram showing the configuration of an electrode drying automatic control system according to the present invention.
Figure 2 is a schematic diagram showing the structure of the oven in the electrode drying automatic control system according to the present invention.
3 is a schematic diagram showing a specific structure of an oven according to an embodiment of the present invention.
4 is a graph showing a photograph obtained by converting an image of an electrode surface into a gray scale and a gray scale value accordingly.
5 and 6 are schematic views showing a specific structure of an oven according to another embodiment of the present invention.
7 is a schematic view showing the shape of a shield frame according to another embodiment of the present invention.
8 is a schematic diagram showing the structure of a shield and an infrared heater according to an embodiment of the present invention.
9 is a schematic diagram showing the structure of a shielding frame and an infrared heater according to another embodiment of the present invention.
10 is a flowchart illustrating a procedure of an automatic electrode drying control method according to the present invention.
11 is a photograph and graph showing the change in the drying degree of the electrode according to the change in the position of the shielding frame in the embodiment of the present invention.

Hereinafter, the present invention will be described in detail. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined in

In the present application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, when a part of a layer, film, region, plate, etc. is said to be “on” another part, it includes not only the case where the other part is “directly on” but also the case where there is another part in between. Conversely, when a part of a layer, film, region, plate, etc. is said to be “under” another part, it includes not only cases where it is “directly under” another part, but also cases where another part is in between. In addition, in the present application, “on” may include the case of being disposed not only on the upper part but also on the lower part.

Hereinafter, the present invention will be described in detail.

1 is a block diagram showing the configuration of an electrode drying automatic control system according to the present invention.

1, the electrode drying automatic control system according to the present invention provides a space in which the electrode is dried, the oven having a hot air nozzle and an infrared heater therein; a photographing unit located in the oven and obtaining an image or an image by photographing the surface state of the electrode in real time; a measuring unit that converts the image or image into gray scale and measures a gray value of the converted image; and a control unit that determines the drying level of the electrode from the gray level value and automatically controls the drying intensity of the electrode therefrom.

As described above, the drying conditions of the electrode greatly affect the quality and physical properties of the electrode. In the past, the initial process conditions were determined in advance and the process conditions were adjusted by drying the electrode and then evaluating the product dryness and physical properties. In this case, there was a problem in that it was difficult to control the drying of the electrode in real time. To this end, there is a method to indirectly evaluate the drying level at each drying time point of the electrode by measuring the solvent exhaust amount or the electrode surface temperature at each drying point of the electrode, but even in this case, the real-time drying degree of the electrode, the deviation of the dryness, and the control of the surface bonding are limited. there is a problem called

The present invention obtains an image of the surface of the electrode in real time, and controls the drying intensity of the electrode using the gray value obtained therefrom, so that the degree of drying of the electrode can be automatically controlled in real time.

Meanwhile, in the present invention, the x-axis means the direction in which the electrode is transported, and the y-axis is the width direction of the electrode, which means a direction perpendicular to the transport direction of the electrode in the electrode surface. The z-axis is a direction perpendicular to the electrode surface, and corresponds to the injection direction of the hot air or the irradiation direction of infrared rays.

Hereinafter, the configuration of the electrode drying apparatus according to the present invention will be described in detail.

Figure 2 is a schematic diagram showing the structure of an oven in the electrode drying automatic control system of the electrode according to the present invention, Figure 3 is a schematic diagram showing the specific structure of the oven according to an embodiment of the present invention.

2 and 3 , the electrode drying apparatus 100 according to the present invention includes an oven 120 . The oven 120 has a chamber shape and provides a space in which the electrode 110 is dried, so that the electrode to be dried is temporarily accommodated in the drying process, and heat from the inside can be prevented from escaping to the outside for drying. there is.

Meanwhile, the electrode may have a structure in which an electrode active material layer is formed by coating an electrode slurry containing an electrode active material on a current collector. The electrode slurry may be applied to at least one surface of the current collector.

In this case, the current collector may be a positive electrode current collector or a negative electrode current collector, and the electrode active material may be a positive electrode active material or a negative electrode active material. In addition, the electrode slurry may further include a conductive material and a binder in addition to the electrode active material.

In the present invention, the positive electrode current collector is generally made to have a thickness of 3 to 500 μm. The positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. For example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel. Carbon, nickel, titanium, silver, etc. surface-treated on the surface of the can be used. The current collector may increase the adhesion of the positive electrode active material by forming fine irregularities on the surface thereof, and various forms such as a film, sheet, foil, net, porous body, foam body, and non-woven body are possible.

In the case of a sheet for a negative electrode current collector, it is generally made to a thickness of 3 to 500 μm. Such a negative current collector is not particularly limited as long as it has conductivity without causing chemical change in the battery. For example, the surface of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel. Carbon, nickel, titanium, a surface-treated material such as silver, aluminum-cadmium alloy, etc. may be used. In addition, like the positive electrode current collector, the bonding strength of the negative electrode active material may be strengthened by forming fine irregularities on the surface, and may be used in various forms such as a film, sheet, foil, net, porous body, foam, non-woven body, and the like.

In the present invention, the positive active material is a material capable of causing an electrochemical reaction, as a lithium transition metal oxide, containing two or more transition metals, for example, lithium cobalt oxide (LiCoO ₂ ) substituted with one or more transition metals. ), layered compounds such as lithium nickel oxide (LiNiO ₂ ); lithium manganese oxide substituted with one or more transition metals; Formula LiNi _1-y M _y O ₂ (wherein M = Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn or Ga, including at least one of the above elements, 0.01≤y≤0.7) Lithium nickel-based oxide represented by; Li _1+z Ni _1/3 Co _1/3 Mn _1/3 O ₂ , Li _1+z Ni _0.4 Mn _0.4 Co _0.2 O ₂ , etc. Li _1+z Ni _b Mn _c Co _{1-(b+c+d )} M _d O _(2-e) A _e (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) a lithium nickel cobalt manganese composite oxide; 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 olivine-based lithium metal phosphate represented by), but is not limited thereto.

The negative electrode active material includes, for example, carbon such as non-graphitizable carbon and graphitic carbon; Li _x Fe ₂ O ₃ (0≤x≤1), Li _x WO ₂ (0≤x≤1), Sn _x Me _1-x Me' _y O _z (Me: Mn, Fe, Pb, Ge; Me' : metal composite oxides such as Al, B, P, Si, elements of Groups 1, 2, and 3 of the periodic table, halogen; 0<x≤1;1≤y≤3;1≤z≤8); lithium metal; lithium alloy; silicon-based alloys; tin-based alloys; SnO, SnO ₂ , PbO, PbO ₂ , Pb ₂ O ₃ , Pb ₃ O ₄ , Sb ₂ O ₃ , Sb ₂ O ₄ , Sb ₂ O ₅ , GeO, GeO ₂ , Bi ₂ O ₃ , Bi ₂ O ₄ , metal oxides such as Bi ₂ O ₅ ; conductive polymers such as polyacetylene; A Li-Co-Ni-based material or the like can be used.

The conductive material is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive active material. Such a conductive material is not particularly limited as long as it has conductivity without causing a chemical change in the battery. For example, graphite such as natural graphite or 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 powder; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives may be used.

The binder is a component that assists in bonding between the active material and the conductive material and bonding to the current collector, and is typically added in an amount of 1 to 30% by weight based on the total weight of the mixture including the positive electrode active material. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, poly propylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butyrene rubber, fluororubber, various copolymers, and the like.

Meanwhile, such an electrode slurry may be prepared by dissolving an electrode active material, a conductive material, a binder, and the like in a solvent. The solvent is not particularly limited in its kind as long as it can disperse the electrode active material and the like, and either an aqueous solvent or a non-aqueous solvent may be used. For example, as the solvent, the solvent may be a solvent generally used in the art, dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP) ), acetone, or water, and any one of them or a mixture of two or more thereof may be used. The amount of the solvent used is not particularly limited, as long as it can be adjusted so that the slurry has an appropriate viscosity in consideration of the application thickness of the slurry, production yield, workability, and the like.

The oven 120 includes a hot air nozzle 124 and an infrared heater 125 for drying the electrode 110 therein. 4 and 5 , the hot air nozzle 124 and the infrared heater 125 may be spaced apart from each other at regular intervals along the transfer direction (MD direction) of the electrode 110 and are perpendicular to the electrode 110 . Apply hot air or infrared rays in one direction. In FIGS. 2 and 3 , the hot air nozzle 124 and the infrared heater 125 are shown as being positioned above the electrode 110 , that is, on the lower surface of the ceiling of the oven 120 , but the electrode active material layers are formed on both sides of the current collector. In this case, the hot air nozzle 124 and the infrared heater 125 may be located both above and below the electrode 110 .

On the other hand, the hot air nozzle 124 includes a body portion and a spraying portion. The main body constitutes the body of the hot air nozzle, and the hot air nozzle 124 is fixed to the ceiling of the oven. In addition, the inside of the main body is empty, and the hot air transmitted from a hot air supply source (not shown) is transferred to the injection unit. On the other hand, the lower surface of the main body is provided with a spraying unit. The injection unit communicates with the main body, and the injection port through which the hot air is injected is formed on the lower surface of the injection unit. The injection hole may have a structure in which a plurality of pores are arranged at regular intervals.

On the other hand, the infrared heater 125 may include an infrared lamp for irradiating infrared rays to the electrode, and a holder for supporting or mounting the infrared lamp. The shape of the infrared lamp is not particularly limited, and, for example, a rod-shaped lamp may be arranged in parallel along the transport direction of the electrode while extending in the width direction of the electrode.

The hot air nozzle 124 and the infrared heater 125 may be alternately arranged along the moving direction of the electrode 110 in order to evenly supply hot air and infrared light to the surface of the electrode 110 . However, there is no particular limitation on the arrangement form, and a person skilled in the art can appropriately design and change the arrangement method of the hot air nozzle 124 and the infrared heater 125 according to drying conditions.

In addition, the oven 120 may include a transfer roller 128 for transferring the electrode. A plurality of the conveying rollers 128 may be disposed to be spaced apart from each other at regular intervals along the conveying direction of the electrode 110 , and support the electrode 110 during the drying process, and the dried electrode 110 may be heated in the oven 120 . ) is transferred to the outside.

The oven 120 may be divided into a plurality of drying zones. When an overdrying or non-drying situation occurs in the drying process of the electrode 110 , it is necessary to appropriately dry the electrode 110 while changing the drying intensity. By dividing the oven 120 into a plurality of drying zones, each drying zone Drying conditions can be controlled independently. 3, the oven 120 is shown in a shape partitioned into three drying zones, and in the specification of the present invention, the three drying zones are a first drying zone 121, a second drying zone along the transport direction of the electrode 110. The second drying zone 122 and the third drying zone 123 are named. In this case, for example, when the electrode is sufficiently dried in the first drying zone 121 and the second drying zone 122 , the drying strength of the electrode is reduced in the third drying zone 123 so that the degree of drying of the electrode is appropriate. can do.

In this case, the first drying zone 121 , the second drying zone 122 , and the third drying zone 123 may be spaces physically partitioned by actually installing an inner wall between the drying zones, and in the drying zone It may be an abstractly partitioned space depending on the drying conditions to be performed.

In addition, the real-time surface condition evaluation apparatus 100 of the electrode according to the present invention includes a photographing unit 130 that obtains an image or an image by photographing the surface condition of the electrode 110 in real time.

In one example, the photographing unit 130 may be located inside the oven 120 to directly photograph the surface state of the electrode 110 .

The photographing unit 130 includes a lighting (not shown) and an image sensor. The illumination irradiates light to the portion to be photographed so that the image sensor can smoothly photograph the image of the surface of the electrode 110 . For the illumination, for example, an LED light source may be used. The image sensor is to obtain an image or image by photographing the surface of the electrode 110, for example, may be a camera. The lighting and image sensors constituting the photographing unit 130 may be disposed through the outer wall of the oven.

On the other hand, the photographing unit 130 can perform the photographing process smoothly, and in order to prevent the lighting and the camera constituting the photographing unit 130 from being exposed to excessively high temperature, a relatively low temperature in the oven 120 . It is preferable to place In addition, it is preferable that the photographing unit 130 is positioned where the photographing field of view is not blocked by the hot air nozzle 124 and the infrared heater 125 in the oven 120 . Therefore, the photographing unit 130 may be located in a place where the hot air nozzle 124 and the infrared heater 125 are not disposed, and specifically may be located between the drying zones. Referring to FIG. 3 , the photographing unit 130 is located in the area between the first drying zone 121 and the second drying zone 122 and in the area between the second drying zone 122 and the third drying zone 123 . All can be located. In addition, although the photographing unit 130 is illustrated as being located on the upper portion of the electrode 110 in FIGS. 4 and 5 , when the electrode active material layers are formed on both sides of the current collector, the photographing unit 130 is positioned above and below the electrode. can all be located in

In addition, the real-time surface dry state evaluation apparatus 100 of the electrode according to the present invention further includes a cooling device 131 for cooling the photographing unit 130 . The cooling device 131 prevents the photographing unit 130 from being damaged by the high-temperature environment in the oven 120 to enable continuous shooting. The cooling device 131 may be fastened or attached to the photographing unit 130 from the outside of the oven 120 to prevent a temperature change inside the oven 120 . The cooling device 131 is not particularly limited in its shape as long as it can cool the photographing unit 130, for example, it is a cooling jacket that surrounds the photographing unit 130 and contains a refrigerant or the like therein. can

Also, as shown in FIG. 3 , the photographing unit 130 may be inserted into the oven 120 , but the photographing unit 130 may be located outside the oven 120 . In this case, the photographing unit 130 may photograph the surface of the electrode through a viewing window formed on the outer wall of the oven.

Meanwhile, referring to FIG. 1 , the automatic electrode drying control system according to the present invention includes a measurement unit 140 for measuring the gray value of the image or the image.

4 is a graph showing a photograph obtained by converting an image of an electrode surface into a gray scale and a gray scale value accordingly.

The measuring unit 140 converts the image or image to gray scale, and measures a gray value of the converted image. Conversion to gray scale is to form a black-and-white image by designating each pixel on a color image the contrast or density of black and white instead of color. Specifically, each pixel constituting a color image has a pixel value representing the brightness of each of the three primary colors, R (Red), G (Green), and B (Blue). In each pixel, the average value of the values representing the brightness of each of the three primary colors can be designated as a gray level. However, there may be various methods for converting to gray scale, and the present invention is not limited thereto.

According to the present invention, the dry state of the electrode surface can be intuitively recognized by converting the image or image photographed by the photographing unit 130 into gray scale and uniformly checking the contrast displayed on the image or image. In addition, it is possible to quantitatively evaluate the dry state of the electrode surface through conversion to gray scale.

Referring to FIG. 4 together with FIGS. 2 and 3 , the gray level value may be measured in the width direction of the electrode 110 . This is to observe the occurrence of a deviation in the degree of drying according to the width direction of the electrode 110 . In general, the side portion based on the width direction of the electrode 110 overlaps the heat emitted from the hot air nozzle 124 or the infrared heater 125, so the drying rate is faster than the drying rate of the central portion, so this dryness deviation occurs. will do In the present invention, by measuring the gray level value in the width direction of the electrode 110 , it is possible to check the dryness deviation for each drying time point and each part of the electrode 110 .

Specifically, as shown in FIG. 4 , a point to be measured is selected on the image converted to gray scale, and an imaginary line formed parallel to the width direction is drawn. With respect to a pixel at a point located on the virtual line, a gray level value represented by the pixel may be represented as a graph. In the graph of FIG. 7 , the horizontal axis is a position along the width direction of the electrode, which means a distance away from the center of the electrode (A is the center, and F indicates a point closer to the side). Then, while drying the electrode, a change in the gray level value for a predetermined point located on the virtual line may be plotted with time.

In addition, referring to FIG. 1 , the electrode drying automatic control system 100 according to the present invention determines the drying level of the electrode from the gray level value, and includes a control unit 150 for automatically controlling the drying strength of the electrode therefrom. include

The control unit 150 determines the dry level of the electrode surface from the gray level value. The control unit 150 is connected to the measurement unit 140 in a network, so that the gray level value stored in the measurement unit can be received and analyzed.

Specifically, the control unit 150 controls the drying level for each part or drying time of the electrode 110 from the gray level value, that is, the change in the dryness of the electrode 110, whether the drying is completed, the dryness deviation between the width directions, and Quantify the occurrence of surface defects. In the present invention, unlike the method for evaluating the surface dry state by the naked eye or an infrared thermometer, the drying level of the electrode 110 can be quantified through a gray level value and quantitatively evaluated.

In addition, the control unit 150 automatically controls the drying intensity for each part of the electrode according to the drying level. There are various methods of controlling the drying intensity of the electrode 110 before, for example, the drying intensity is to be controlled through the transfer speed of the electrode 110, the temperature of the hot air, the flow rate of the hot air, and the output control of the infrared heater. can

5 and 6 are schematic views showing a specific structure of an oven according to another embodiment of the present invention.

5 and 6 , the automatic electrode drying control system according to the present invention further includes at least one shielding frame 160 positioned between the infrared heater or hot air nozzle and the electrode.

Radiant heat transfer by infrared rays may be blocked or reduced in the portion where the shielding frame 160 is installed. The electrode drying apparatus according to the present invention can control the drying speed according to each part of the electrode 110 by adjusting the area where the electrode 110 is exposed to infrared rays through the shielding frame 160 as needed. This makes it possible to control the level of drying across the width directions. At this time, the shielding frame 160 may be disposed for all the infrared heaters 130 provided in the oven 120 . In this case, the size and number of the shielding frames 160 can be set in various ways according to the drying process. For example, a plurality of shields having a small width in the length (y-axis direction) may be disposed between the infrared heater and the electrode. For example, FIG. 6 illustrates a shape in which two shielding frames 160 smaller than the width direction length of the electrode active material layer 112 are disposed.

Referring to FIG. 6 , the shielding frame 160 may be movable along the width direction of the electrode 110 . Through this, it is possible to improve the deviation of the dryness in the width direction of the electrode 110 . The shielding frame 160 is positioned on a portion with a high degree of dryness while moving along the width direction of the electrode, thereby reducing the drying rate of the portion with a high degree of dryness. For example, in FIG. 3 , the shielding frame 160 is illustrated as being positioned on both sides of the electrode in the width direction.

In the present invention, the shielding frame 160 may be a plate-shaped member made of a material that does not transmit infrared rays. Specifically, any material may be used for the shielding frame 160 as long as it does not transmit infrared rays without being damaged in a high-temperature environment in the oven. In addition, the shielding frame 160 may be made of only a material that does not transmit infrared light, and infrared transmits through a metal or polymer material constituting the body (here, a metal or polymer material irrelevant to infrared blocking can be used) It may be coated with a material that does not work. Examples of the material through which the infrared rays are not transmitted include, but are not limited to, a glassy insulating material, an inorganic material such as a metal oxide, a carbon-based material, and the like.

7 is a schematic view showing the shape of a shield frame according to another embodiment of the present invention.

In the present invention, the shape of the shielding frame 160 can be variously modified according to drying conditions. The shielding frame 160 may not form a hole in the surface to completely block infrared rays. Alternatively, the shielding frame 160 may have a structure in which a hole is formed in the infrared irradiation direction so that only a part of the infrared rays can be blocked as shown in FIG. 7 .

Referring to FIG. 7 , the shielding frame 160 may be one in which the plurality of holes are patterned at regular intervals as shown in (a). Alternatively, the shielding frame 160 may have a mesh or mesh structure as shown in (b). In this case, the shielding frame 160 may be composed of a single layer or multiple layers. When the shielding frame 160 has a single-layer structure, it may be manufactured by attaching a single layer of mesh or mesh structure to a frame capable of supporting it. Alternatively, the mesh or mesh structure attached to a material through which infrared rays can be transmitted may be used. In the case where the shielding frame 160 has a multi-layer structure, a fiber-type material is woven to form pores of a certain size, and a plate-shaped material manufactured by laminating a plurality of these may be used.

8 is a schematic diagram showing the structure of a shield and an infrared heater according to an embodiment of the present invention.

Referring to FIG. 8 , as described above, the infrared heater 125 includes an infrared lamp 126 and a holder 127 on which the infrared lamp 126 is mounted. At this time, the shielding frame 160 may be moved in a sliding manner while being fixed to the cradle 127 so as to be spaced apart from the infrared lamp 126 by a predetermined distance. In the case of FIG. 8 , the cross section of the cradle 127 on which the infrared lamp 126 is mounted has a trapezoidal shape, and the length in the x-axis direction increases from the top to the bottom of the cradle 127 . The shielding frame 160 has a portion facing both ends of the holder 127 in the x-axis direction is bent toward the holder 127 and spans the outer wall (sidewall) of the holder 127 . Since the holder 127 has a trapezoidal cross-sectional shape, the shielding frame 160 may be fixed to the holder 127 . At this time, since the bent portion of the shielding frame 160 is not completely attached to the holder 127, the shielding frame 160 can block transmission of infrared rays while moving along the width direction (y-axis direction).

However, the above description is an example of a method in which the infrared heater 125 and the shielding frame 160 are coupled, and if the shielding frame 160 can move in the width direction while being fixed to the holder 127, the holder There is no particular limitation on the shape and coupling method of the 127 and the shielding frame 160 .

9 is a schematic diagram showing the structure of a shielding frame and an infrared heater according to another embodiment of the present invention.

Referring to FIG. 9 , the oven 120 is disposed in the space between the infrared heater 125 and the electrode active material layer 112 , and further includes a rail 161 on which at least one shielding frame 160 can be mounted. do. The shielding frame 160 may move on the rail 161 in a sliding manner.

The rail 161 is not particularly limited in shape as long as the shielding frame 160 can move in a sliding manner, but is preferably located outside the path through which infrared rays are irradiated so as not to block infrared rays. For example, the rail 161 may be a rectangular parallelepiped frame supporting both ends of the shielding frame 160 in the x-axis direction (the electrode transport direction) as shown in FIG. 9A . In this case, an empty space is formed in the middle of the rail 161 to provide a space for the shielding frame 160 to move in a sliding manner on the rail 161, and has a structure that does not interfere with the irradiation of infrared rays. Also, referring to FIG. 9B , the rail 161 is designed to fix the upper and lower surfaces of the guarding frame 160 . The blanking frame 60 is mounted on the space between the rails 161 and moves in a sliding manner along the width direction on the rails 161, and is located on a high drying rate, so that the drying rate of the high drying rate is high. can reduce In this case, the number of shielding frames 160 mounted on the rail 161 may be appropriately designed according to the size of the electrode 110 , the formation pattern of the electrode active material layer 112 , and drying conditions.

As described above, when the shielding frame 160 is positioned between the infrared heater 125 and the electrode 110 in the oven 120 , the control unit 150 controls the position of the shielding frame 160 , so that the electrode 110 . By controlling the area exposed to the infrared rays, it is possible to control the drying intensity for each part of the electrode 110 . For example, as shown in FIG. 6 , when the shielding frame 160 is positioned on the side in the width direction (y-axis direction) of the electrode active material 112 layer, the drying rate of the side portion is reduced compared to before, so that the drying between the width directions is reduced. Deviation can also be improved.

In addition, the present invention provides a method for automatically controlling electrode drying.

10 is a flowchart illustrating a procedure of an automatic electrode drying control method according to the present invention.

Referring to FIG. 10 , the method for automatically controlling electrode drying according to the present invention includes the steps of transferring the electrode into the oven as described above (S10); While drying the electrode, obtaining an image or image by photographing the surface state of the electrode in real time (S20); measuring a gray level value for the image or image (S30); determining the drying level of the electrode from the gray level value (S40); and automatically controlling the drying strength of the electrode by reflecting the drying level of the electrode (S50).

The present invention obtains an image of the surface of the electrode in real time, and controls the drying intensity of the electrode using the gray value obtained therefrom, so that the degree of drying of the electrode can be automatically controlled in real time.

Hereinafter, each step of the automatic electrode drying control method according to the present invention will be described in detail.

<Production of electrode>

First, an electrode is manufactured by forming an electrode active material layer including an electrode active material on a current collector. Specific details regarding the electrode are the same as described above. When the electrode is put in, the electrode is put into the oven as described above to start drying.

<Drying the electrode and photographing the surface condition of the electrode>

When the electrode is put into the oven, an image or image is obtained by photographing the surface state of the electrode in real time while drying the electrode through an infrared heater and a hot air nozzle. This may be performed by the photographing unit as described above.

The photographing unit includes a lighting and an image sensor, and is located between the drying zones partitioned in the oven. In addition, the photographing unit may be located inside the oven to directly photograph the surface state of the electrode, or located outside the oven may photograph the surface state of the electrode through a viewing window formed on the outer wall of the oven. In this case, the process of cooling the photographing unit may be performed to prevent the photographing unit from being damaged by the high temperature environment in the oven and to keep the photographing unit running.

<Conversion of the captured image or video>

When an image or image of the electrode surface is captured through the photographing unit, a gray level value is measured for the image or image. Specifically, the step of measuring the gray scale value includes converting the image or the image to a gray scale and measuring a gray value of the converted image. This may be performed by the control unit.

According to the present invention, the dry state of the electrode surface can be intuitively recognized by converting the image or image photographed by the photographing unit into gray scale and uniformly checking the contrast displayed on the image or image. In addition, it is possible to quantitatively evaluate the dry state of the electrode surface through conversion to gray scale.

In this case, the gray level value may be measured in the width direction of the electrode. As described above, on the grayscale-converted image, a point to be measured is selected, and an imaginary line formed parallel to the width direction is drawn. Subsequently, with respect to a pixel located on the virtual line, a gray level value indicated by the pixel may be represented as a graph. Through this, it is possible to check the degree of variation in the dry state and dryness according to the width direction of the electrode.

<Determination of drying level and control of drying strength>

When the gray level value is measured, the step of determining the dryness level of the electrode is performed therefrom. The step includes a process of quantifying the drying level according to each part of the electrode and the drying time of the electrode. Specifically, the change in the dryness of the electrode, whether the drying is completed, the dryness deviation between the width directions, and whether a surface defect occurs quantify

Thereafter, the drying strength of the electrode is automatically controlled by reflecting the drying level of the electrode. Specifically, the step includes the process of automatically controlling the transfer speed of the electrode, the temperature of the hot air, the flow rate of the hot air, and the output of the infrared heater.

In addition, when the shielding frame is disposed between the infrared heater and the electrode in the oven, automatically controlling the drying intensity of the electrode may include controlling an area to which the electrode is exposed to hot air or infrared rays.

Hereinafter, examples will be given to help the understanding of the present invention be described in detail. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the following examples. The embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art.

Example

97.6 parts by weight of artificial graphite and natural graphite (weight ratio: 90:10) functioning as an anode active material, 1.2 parts by weight of styrene-butadiene rubber (SBR) functioning as a binder, 1.2 parts by weight of carboxymethyl cellulose (CMC) , a negative electrode mixture was prepared. A negative electrode slurry was prepared by dispersing this negative electrode mixture in ion-exchanged water functioning as a solvent. This slurry was coated on both sides of a copper foil having a thickness of 20 μm and dried to prepare a negative electrode.

While the cathode was put into an oven and dried, an image was obtained by photographing the surface of the electrode through a camera positioned between the drying zones. This is shown in Fig. 11 (a). At this time, in the photograph of FIG. 11 , the left side (A) corresponds to the width direction side portion of the electrode, and the right side (C) corresponds to the center portion of the electrode. At this time, during the drying process, drying was performed in a state in which a plurality of shielding frames were arranged in a line at the points (B) and (C) of the electrode along the width direction.

The image was converted to gray scale through image analysis software in the measurement unit, and the gray scale value was measured. At this time, as shown in (a) of FIG. 11 , the gray level value along the width direction of a specific point was measured.

Thereafter, by moving the shielding frame at the point (C) in the width direction to open the point (C), the part (C) was exposed to an infrared heater and drying was performed. A graph showing a photograph of the drying result and a gray value according to it is shown in (b).

Referring to FIG. 11 , when a shield is positioned between points (B) and (C), the drying speed of the part is slow because the shield blocks infrared rays, and accordingly, the gray level value is lower than (A) can be known

At this time, when the screen at the point (C) was moved and exposed to infrared rays and dried, the drying speed of the part was increased. it can be seen that

That is, according to the present invention, the dryness of the electrode can be automatically controlled for each drying time point or for each drying part using the gray level value obtained by photographing the surface state of the electrode.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains. Accordingly, the drawings disclosed in the present invention are for explanation rather than limiting the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these drawings. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Meanwhile, in this specification, terms indicating directions such as up, down, left, right, front, and back are used, but these terms are for convenience of explanation only, and may vary depending on the location of the object or the position of the observer. It is self-evident that it can

100: electrode drying automatic control system
110: electrode
111: current collector
112: electrode active material layer
120: oven
121: first drying zone
122: second drying zone
123: third drying zone
124: hot air nozzle
125: infrared heater
126: infrared lamp
127: cradle
128: conveying roller
130: shooting department
131: cooling device
140: measurement unit
150: control unit
160: cover frame
161: rail

Claims (15)

an oven providing a space in which the electrode is dried, and having a hot air nozzle and an infrared heater therein;
a photographing unit located in the oven and obtaining an image or an image by photographing the surface state of the electrode in real time;
a measuring unit converting the image or the image into gray scale and measuring a gray value of the converted image; and
and a controller for determining the drying level of the electrode from the gray level value, and automatically controlling the drying intensity of the electrode based thereon.
According to claim 1,
in the oven,
The electrode drying automatic control system in which the hot air nozzle and the infrared heater are alternately arranged along the moving direction of the electrode.
According to claim 1,
The oven is divided into a plurality of zones,
The electrode drying automatic control system is located between the photographing unit.
According to claim 1,
Electrode drying automatic control system further comprising a cooling device for cooling the photographing unit.
According to claim 1,
The gray level value is measured in the width direction of the electrode drying automatic control system.
According to claim 1,
The measurement unit is an electrode drying automatic control system that quantifies the drying level for each part of the electrode and the drying time of the electrode from the gray level value.
7. The method of claim 6,
The control unit is an electrode drying automatic control system for automatically controlling the drying intensity for each part of the electrode according to the drying level.
According to claim 1,
The dry strength is,
Electrode drying automatic control system that is controlled through the transfer speed of the electrode, the temperature of the hot air, the flow rate of the hot air and the output control of the infrared heater.
According to claim 1,
Electrode drying automatic control system further comprising at least one shielding frame positioned between the infrared heater and the electrode.
10. The method of claim 9,
The control unit, by controlling the position of the shielding frame, the electrode drying automatic control system for controlling the area to which the electrode is exposed to hot air or infrared rays.
transferring the electrode into an oven according to claim 1 ;
obtaining an image or image by photographing the surface state of the electrode in real time while drying the electrode;
measuring a gray level value for the image or image;
determining the drying level of the electrode from the gray level value; and
A method of automatically controlling electrode drying, comprising the step of automatically controlling the drying strength of the electrode by reflecting the drying level of the electrode.
12. The method of claim 11,
The method for automatically controlling electrode drying, wherein the gray value is measured in the width direction of the electrode.
12. The method of claim 11,
The step of determining the drying level of the electrode is,
A method for automatically controlling electrode drying, comprising the step of quantifying the drying level according to each part of the electrode and the drying time of the electrode.
12. The method of claim 11,
The step of automatically controlling the drying strength of the electrode is,
Electrode drying automatic control method comprising the process of automatically controlling the transfer speed of the electrode, the temperature of the hot air, the flow rate of the hot air, and the output of the infrared heater.
12. The method of claim 11,
The step of automatically controlling the drying strength of the electrode is,
Electrode drying automatic control method comprising the process of controlling the area to which the electrode is exposed to hot air or infrared rays.

Images