Apparatus for measuring degree of drying of electrode and electrode coating apparatus comprising same

Abstract

An apparatus for measuring the degree of drying of an electrode according to some embodiments may be configured to be positioned behind, with respect to a machine direction (MD) of a current collector, a top surface drying apparatus configured to dry slurry coated on the top surface of the current collector, and be able to measure the degree of drying of each of a center part and a side part of an active material layer dried by the top surface drying apparatus. In some embodiments of the present invention, the degree of drying of an active material layer of a top surface coating electrode is digitalized so that a correlation between process variables of a top surface coating device and a top surface drying device and the degree of drying of the active material layer of the top surface coating electrode can be derived. In some embodiments of the present invention, when an active material layer of a top surface coating electrode is not properly dried, a quick response thereto is enabled so that contamination of rollers positioned in front of a top surface drying device with reference to an MD direction of a current collector and / or a roller facing a back surface coating device can be prevented.

Description

Electrode drying degree measuring device and electrode coating device including the same

[0001] The present disclosure claims the benefit of priority based on Korean Patent Application No. 10-2024-0047177 filed April 8, 2024, and all contents of Korean Patent Application No. 10-2024-0047177 are incorporated by reference into the present disclosure.

[0002] The present invention relates to an electrode drying degree measuring device and an electrode coating device including the same.

[0003]

[0004] Recently, there has been growing interest in rechargeable batteries that can be used repeatedly for extended periods through recharging, as a way to reduce carbon emissions while decreasing dependence on fossil fuels. In particular, among rechargeable batteries, lithium-ion batteries are being actively researched and developed due to their excellent energy density and lifespan. Accordingly, lithium-ion batteries are being used in various fields, including portable electronic devices, vehicles, and ESS.

[0005] Generally, the electrodes of a lithium secondary battery are double-sided coated electrodes in which active material layers are located on both sides of a current collector. The manufacturing process of a conventional double-sided coated electrode is described as follows with reference to FIG. 1. However, the number and arrangement of the rollers shown in FIG. 1 are merely arbitrarily determined for the convenience of explanation.

[0006] The current collector (B) is transported by rollers (R1 to R11), and the top surface coating device (C1) coats the top surface of the current collector (B) with a first slurry (S1) containing an active material, a binder, a conductive material, and a solvent. The top surface drying device (D1) dries the first slurry (S1) to evaporate the solvent. The top surface coated electrode thus manufactured is transported by rollers (R1 to R11), and the back surface coating device (C2) coats the back surface of the current collector (300) with a second slurry (S2) containing an active material, a binder, a conductive material, and a solvent. The back surface drying device (D2) dries the second slurry (S2) to evaporate the solvent. Afterward, a double-sided coated electrode is manufactured through processes such as rolling, slitting, and vacuum drying.

[0007] As described above, conventionally, there was no device for measuring the degree of drying of the first active material layer (A1) located behind the top surface drying device (D1) based on the MD (machine direction) of the current collector (B). Conventionally, only the loading level of the active material within the first active material layer (A1) was measured from the color map of the first active material layer (A1).

[0008] Therefore, conventionally, it was difficult to quantify the degree of drying of the first active material layer (A1), making it difficult to derive a correlation between the process variables of the top surface coating device (C1) and the top surface drying device (D1) and the degree of drying of the first active material layer (200).

[0009] In addition, conventionally, when the drying of the first active material layer (A1) was not properly performed, the rollers (R5~R11) located behind the top surface drying device (D1) based on the MD (machine direction) of the current collector (B) became contaminated. Consequently, the quality and production yield of the double-sided coated electrode were reduced, and there was a problem of ultimately degrading the performance of the cell. In particular, this problem can be most severe when the roller (R8) facing the back surface coating device (C2) is contaminated.

[0010]

[0011] The problem that the technical concept of the present invention aims to solve is to quantify the degree of drying of the active material layer of a top surface coated electrode so as to derive a correlation between the process variables of the top surface coating device and the top surface drying device and the degree of drying of the active material layer of the top surface coated electrode.

[0012] Another problem that the technical concept of the present invention aims to solve is to enable a rapid response when the active material layer of the top-face coated electrode is not properly dried, thereby preventing contamination of the rollers located ahead of the back-face coating device and / or the rollers facing the back-face coating device based on the MD direction of the current collector.

[0013]

[0014] Some embodiments of the present invention capable of solving the above problem are as follows.

[0015] The electrode drying degree measuring device according to some embodiments may be configured to be positioned behind the top surface drying device configured to dry a slurry coated on the top surface of the current collector based on the machine direction (MD) of the current collector, and to measure the drying degree of the center and side portions of the active material layer dried by the top surface drying device, respectively.

[0016] In some embodiments, the electrode drying degree measuring device may be configured to measure the drying degree of the center portion of the active material layer from the brightness of the center portion of the active material layer and to measure the drying degree of the side portion of the active material layer from the brightness of the side portion of the active material layer.

[0017] In some embodiments, the electrode drying degree measuring device may include an image sensor configured to calculate the brightness of the center portion and the side portion of the active material layer, respectively, from an image of the active material layer.

[0018] In some embodiments, the electrode drying degree measuring device may include an optical sensor configured to irradiate light onto the active material layer and analyze the light reflected from the active material layer to calculate the brightness of the center portion and the side portion of the active material layer, respectively.

[0019] In some embodiments, the electrode drying degree measuring device may include a transmitter configured to transmit a defect signal to a display device if the brightness of the center portion of the active material layer is lower than a reference value or the brightness of the side portion of the active material layer is higher than the reference value.

[0020] In some embodiments, the electrode drying degree measuring device may include a transmitter configured to transmit a defect signal to a control device if the brightness of the center portion of the active material layer is lower than the non-drying reference value or the brightness of the side portion of the active material layer is higher than the over-drying reference value.

[0021]

[0022] An electrode coating device according to some embodiments may include a top surface drying device configured to dry a first slurry coated on the top surface of a current collector, a back surface coating device configured to coat a second slurry on the back surface of the current collector, and an electrode drying degree measuring device located between the top surface drying device and the back surface coating device based on the machine direction (MD) of the current collector.

[0023] In some embodiments, the electrode coating device may additionally include a top surface coating device configured to coat a first slurry on the top surface of the current collector; and a back surface drying device configured to dry a second slurry coated on the back surface of the current collector.

[0024]

[0025] Some embodiments of the present invention quantify the degree of drying of the active material layer of a top surface coated electrode, thereby enabling the derivation of a correlation between the process variables of the top surface coating device and the top surface drying device and the degree of drying of the active material layer of the top surface coated electrode.

[0026] Some embodiments of the present invention enable a rapid response when the drying of the active material layer of the top surface coated electrode is not properly performed, thereby preventing contamination of rollers located ahead of the top surface drying device and / or rollers facing the back surface coating device based on the MD direction of the current collector.

[0027] The effects of the embodiments of the present invention are not limited to those mentioned above, and other unmentioned effects can be clearly derived and understood by those skilled in the art from the following description. That is, unintended effects resulting from the implementation of the embodiments of the present invention can also be clearly derived and understood by those skilled in the art.

[0028]

[0029] Figure 1 is a diagram illustrating the manufacturing process of a conventional double-sided coated electrode.

[0030] FIG. 2 is a drawing for explaining the location of an electrode drying degree measuring device according to some embodiments and an electrode coating device according to some embodiments.

[0031] Figure 3 is a top view of the top surface coating electrode of zone F in Figure 2.

[0032] Figure 4 is an enlarged view of section F of Figure 2.

[0033]

[0034] Terms or words used in this specification should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning consistent with the technical concept of the invention, based on the principle that the inventor can appropriately define the meaning of terms or words to best describe his invention.

[0035] In this specification, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Furthermore, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only the case where it is "immediately above" the other part, but also the case where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "under" another part, this includes not only the case where it is "immediately below" the other part, but also the case where there is another part in between.

[0036] The embodiments and drawings are merely examples of the invention and do not represent all of the technical ideas of the invention; therefore, it should be understood that there may be various equivalents and modifications that can replace them.

[0037] In describing the present invention, if it is determined that a detailed description of a known configuration or function may obscure the essence of the invention, such detailed description is omitted.

[0038] The drawings are provided to more fully explain the invention to a person skilled in the art; therefore, the shapes, sizes, and number of components in the drawings may be exaggerated, omitted, or schematically depicted for clearer explanation. The shape, size, proportion, and number of each component in the drawings do not entirely reflect the actual shape, size, proportion, and number of each component.

[0039]

[0040] In this specification, "top surface of current collector (B)" refers to one side of the current collector (B) on which the slurry is coated first during the process of manufacturing a double-sided coated electrode. In this specification, "back surface of current collector (B)" refers to the opposite side of the one side of the current collector (B) on which the slurry is coated first during the process of manufacturing a double-sided coated electrode. In this specification, "machine direction (MD) of current collector (B)" refers to the direction of movement of the current collector being transported by a plurality of rollers (R1 to R11) during the manufacturing of a double-sided coated electrode.

[0041]

[0042] One aspect of the present invention relates to an electrode drying degree measuring device.

[0043] Before describing the electrode drying degree measuring device according to some embodiments, the process of manufacturing a double-sided coated electrode is described with reference to FIG. 2. FIG. 2 is a drawing for describing the location of the electrode drying degree measuring device according to some embodiments and the electrode coating device according to some embodiments.

[0044]

[0045] Multiple rollers (R1 to R11) transport the current collector (B). The arrow inside each of the multiple rollers (R1 to R11) shown in FIG. 2 indicates the rotational direction of each of the multiple rollers (R1 to R11).

[0046] The top surface coating device (C1) coats the top surface of the current collector (B) with a first slurry (S1). As a non-limiting example, the top surface coating device (C1) may be a slot die. As a non-limiting example, the first slurry (S1) may include an active material, a binder, a conductive material, and a solvent.

[0047] The top surface drying device (D1) dries the first slurry (S1) coated on the top surface of the current collector (B) to evaporate the solvent within the first slurry (S1). Accordingly, a top surface coated electrode is manufactured in which a first active material layer (A1) is located on the top surface of the current collector (B). The first active material layer (A1) may include an active material, a binder, a conductive material, etc. As a non-limiting example, the top surface drying device (D1) may evaporate the solvent within the first slurry (S1) by spraying air onto the first slurry (S1). As a non-limiting example, there may be multiple regions within the top surface drying device (D1) that differ in the temperature of the air, the speed of the air spray, the amount of air sprayed, etc.

[0048] The back surface coating device (C2) coats the second slurry (S2) on the back surface of the current collector (B). As a non-limiting example, the back surface coating device (C2) may be a slot die. As a non-limiting example, the second slurry (S2) may include an active material, a binder, a conductive material, and a solvent. As a non-limiting example, the first slurry (S1) may have the same composition, viscosity, etc. as the second slurry (S2). As a non-limiting example, the first slurry (S1) may have a different composition, viscosity, etc. as the second slurry (S2).

[0049] The back surface drying device (D2) dries the second slurry (S2) coated on the back surface of the current collector (B) to evaporate the solvent within the second slurry (S2). Accordingly, a double-sided coated electrode is manufactured in which the second active material layer (A2) is located on the back surface of the current collector (B). The second active material layer (A2) may include an active material, a binder, a conductive material, etc. As a non-limiting example, the second active material layer (A2) may have the same composition, thickness, etc. as the first active material layer (A1). As a non-limiting example, the second active material layer (A2) may have a different composition, thickness, etc. as the first active material layer (A1). As a non-limiting example, the back surface drying device (D2) may evaporate the solvent within the second slurry (S2) by spraying air onto the second slurry (S2). As a non-limiting example, there may be multiple regions within the white surface drying device (D2) that differ in the temperature of the air, the speed of the air injection, the amount of air injection, etc.

[0050] The number and arrangement of the plurality of rollers (R1 to R11) shown in FIG. 2; the arrangement of the top surface coating device (C1), the top surface drying device (D1), the back surface coating device (C2), and the back surface drying device (D2); and the thickness of the current collector (B), the first slurry (S1), the first active material layer (A1), the second slurry (S2), and the second active material layer (A2) are merely exemplary.

[0051]

[0052] As a non-limiting example, the current collector (B) may comprise one or more of copper, stainless steel, aluminum, nickel, titanium, calcined carbon; and copper, aluminum, or stainless steel surface-treated with carbon, nickel, titanium, silver, etc.

[0053] As a non-limiting example, the active material may be a positive electrode active material. As a non-limiting example, the positive electrode active material may be a lithium-iron-based oxide (e.g., LiFePO4, etc.), a lithium-manganese-based oxide (e.g., LiMnO2, LiMn2O4, etc.), a lithium-cobalt-based oxide (e.g., LiCoO2, etc.), a lithium-nickel-based oxide (e.g., LiNiO2, etc.), or a lithium-nickel-manganese-based oxide (e.g., LiNi 1-y1 Mn y1 O2(here, 0 <y1<1) 및 LiMn 2-z1 Ni z1 O4 (where 0 < z1 < 2), etc.), lithium-nickel-cobalt oxides (e.g., LiNi 1-y2 Co y2 O2(here, 0 <y2<1) 등), 리튬-망간-코발트계 산화물(예를 들면, LiCo 1-y3 Mn y3 O2(here, 0 <y3<1) 및 LiMn 2-z2 Co z2 O4 (where 0 < z2 < 2), etc.), lithium-nickel-manganese-cobalt oxides (e.g., Li(Ni p1 Co q1 Mn r1 )O2(where, 0<p1<1, 0<q1<1, 0<r1<1, p1+q1+r1=1), Li(Ni p2 Co q2 Mn r2 )O4(where 0<p2<2, 0<q2<2, 0<r2<2, p2+q2+r2=2) etc.), lithium-nickel-cobalt-metal(M) oxide (e.g., Li(Ni p3 Co q3 Mn r3 M s1It may include one or more of )O2(wherein M is selected from the group consisting of Al, Cu, Fe, V, Cr, Ti, Zr, Zn, Ta, Nb, Mg, B, W and Mo, and p3, q3, r3 and s1 are each atomic fractions of independent elements, such that 0<p3<1, 0<q3<1, 0<r3<1, 0<s1<1, p3+q3+r3+s1=1) etc.) and mixtures thereof.

[0054] As a non-limiting example, the active material may be a negative electrode active material. As a non-limiting example, the negative electrode active material may be lithium metal; a graphite-based carbon material such as amorphous, plate-like, flake-like, spherical, or fibrous natural graphite or artificial graphite; an amorphous carbon material such as soft carbon and hard carbon; a metal such as Cu, Ni, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn, or an alloy of said metal and lithium; PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4, Bi2O5, 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, Group 1, 2, and 3 elements of the periodic table, halogens; 0 <x≤1; 1≤y≤3; 1≤z≤8); Si, SiO x(0 <x≤2), Si-Y 합금(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Si은 아님), Sn, SnO2, Sn-Y(상기 Y는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 전이금속, 희토류 원소 및 이들의 조합으로 이루어진 군에서 선택되는 원소이며, Sn은 아님) 및 이들의 혼합물 중 하나 이상을 포함할 수 있다.

[0055] As a non-limiting example, the binder may comprise one or more of polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose, starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer, sulfonated ethylene-propylene-diene terpolymer, styrene-butadiene rubber, styrene-butadiene rubber-carboxymethylcellulose fluororubber, and mixtures thereof.

[0056] As a non-limiting example, the conductive material may include one or more of carbon nanotubes, graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black; conductive fibers such as carbon fibers or metal fibers; metal powders such as carbon fluoride, aluminum, or nickel powder; conductive whiskey such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; polyphenylene; and mixtures thereof.

[0057] As a non-limiting example, the solvent may include one or more of organic solvents such as N-methylpyrrolidone, dimethylformamide, acetone, dimethylacetamide, and mixtures thereof; and water.

[0058]

[0059] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0060] FIG. 2 is a drawing for explaining the location of an electrode drying degree measuring device according to some embodiments and an electrode coating device according to some embodiments.

[0061] In some embodiments, the electrode drying degree measuring device (100) may be located behind the top surface drying device (D1) based on the MD of the current collector. In some embodiments, the electrode drying degree measuring device (100) may be located in front of the first roller (R5) located behind the top surface drying device (D1) based on the MD of the current collector.

[0062] In some embodiments, the electrode drying degree measuring device (100) may be positioned ahead of the back surface coating device (C2) based on the MD of the current collector. In some embodiments, the electrode drying degree measuring device (100) may be positioned ahead of the roller (R8) facing the back surface coating device (C2) based on the MD of the current collector. In some embodiments, the electrode drying degree measuring device (100) may be positioned behind the first roller (R7) located ahead of the back surface coating device (C2) based on the MD of the current collector.

[0063]

[0064] FIG. 3 is a top view of the top surface coating electrode of section F of FIG. 2. Referring to FIG. 3, the first active material layer (A1) has a center portion (A1C) and a side portion (A1S). FIG. 3 is illustrated as having one first active material layer (A1), but this is exemplary and the number of first active material layers may be multiple.

[0065]

[0066] In some embodiments, the electrode drying degree measuring device (100) may be configured to measure the drying degree of the center portion (A1C) and the side portion (A1S) of the first active material layer (A1), respectively. In some embodiments, the electrode drying degree measuring device (100) may be configured to measure the drying degree of the center portion (A1C) of the first active material layer (A1) from the brightness of the center portion (A1C) of the first active material layer (A1). In some embodiments, the electrode drying degree measuring device (100) may be configured to measure the drying degree of the side portion (A1S) of the first active material layer (A1) from the brightness of the side portion (A1S) of the first active material layer (A1).

[0067] As described above, the first active material layer (A1) is formed by evaporating the solvent from the first slurry (S1). If the solvent is not sufficiently evaporated from the first slurry (S1), the solvent remains in the first active material layer (A1). When the solvent is present in the first active material layer (A1) in this manner, the reflectance of the surface of the first active material layer (A1) is lowered by the solvent, and thus the brightness of the first active material layer (A1) decreases. Since the brightness of the first active material layer (A1) decreases as the amount of solvent present in the first active material layer (A1) increases, the degree of dryness of the first active material layer (A1) can be measured from the brightness of the first active material layer (A1). That is, since the degree of drying of the first active material layer (A1) can be quantified through the brightness of the first active material layer (A1), the correlation between the process variables of the top surface coating device (C1) and the top surface drying device (D1), which can affect the degree of drying of the first active material layer (A1), and the degree of drying of the first active material layer (A1) can be derived.

[0068] As a non-limiting example, the above value may be V (Value) in the HSV (Hue, Saturation, Value) color space. As a non-limiting example, the above value may be μ (Red, Green, Blue) in the RGB (Red, Green, Blue) color space. μ is the value obtained by adding the channel values ​​of R, G, and dividing by 3. As a non-limiting example, the above value may be the value in the Munsell color system.

[0069]

[0070] Figure 4 is an enlarged view of section F of Figure 2.

[0071] In some embodiments, the electrode drying degree measuring device (100) may include an image sensor (110) configured to calculate the brightness of the center portion (A1C) and the side portion (A1S) of the first active material layer (A1), respectively, from an image of the first active material layer (A1). In some embodiments, the image sensor (110) may include a camera, a light source, and a data processing unit. In some embodiments, the camera may capture an image of the first active material layer (A1). In some embodiments, the light source may irradiate light onto the first active material layer (A1). As a non-limiting example, the light source may be an LED light source. In some embodiments, the data processing unit may be configured to calculate the brightness of the center portion (A1C) and the side portion (A1S) of the first active material layer (A1), respectively, from an image of the first active material layer (A1) captured by the camera. In some embodiments, the brightness of the center portion (A1C) of the first active material layer (A1) may be the average of the brightnesses measured at several measurement points selected in the portion corresponding to the center portion (A1C) of the first active material layer (A1) in the image of the first active material layer (A1). In some embodiments, the several measurement points may be uniformly distributed in the portion corresponding to the center portion (A1C) of the first active material layer (A1) in the image of the first active material layer (A1). In some embodiments, the brightness of the side portion (A1S) of the first active material layer (A1) may be the average of the brightnesses measured at several measurement points selected in the portion corresponding to the side portion (A1S) of the first active material layer (A1) in the image of the first active material layer (A1). In some embodiments, the various measurement points may be uniformly distributed in the portion corresponding to the side portion (A1S) of the first active material layer (A1) in the image of the first active material layer (A1).

[0072] In some embodiments, the image sensor (110) may include a plurality of cameras, a plurality of lights, or a plurality of data processing units. As a non-limiting example, the image sensor (110) may include three cameras. In this case, one camera may photograph the center portion (A1C) of the first active material layer (A1) and the other two cameras may photograph the side portion (A1S) of the first active material layer (A1). As a non-limiting example, the image sensor (110) may include three lights. In this case, one light may irradiate light onto the center portion (A1C) of the first active material layer (A1) and the other two lights may irradiate light onto the side portion (A1S) of the first active material layer (A1). As a non-limiting example, the image sensor (110) may include three data processing units. At this time, one data processing unit may be configured to calculate the brightness of the center portion (A1C) of the first active material layer (A1), and the remaining two data processing units may be configured to calculate the brightness of the side portion (A1S) of the first active material layer (A1).

[0073] In some embodiments, the electrode drying degree measuring device (100) may include an optical sensor (110') configured to irradiate light onto a first active material layer (A1) and analyze the light reflected from the first active material layer (A1) to calculate the brightness of the center portion (A1C) and the side portion (A1S) of the first active material layer (A1), respectively. In some embodiments, the brightness of the center portion (A1C) of the first active material layer (A1) may be the average of the brightnesses measured at several measurement points selected at the center portion (A1C) of the first active material layer (A1). In some embodiments, the several measurement points may be uniformly distributed at the center portion (A1C) of the first active material layer (A1). In some embodiments, the brightness of the side portion (A1S) of the first active material layer (A1) may be the average of the brightnesses measured at several measurement points selected at the side portion (A1S) of the first active material layer (A1). In some embodiments, the several measurement points may be uniformly distributed at the side portion (A1S) of the first active material layer (A1).

[0074] In some embodiments, the optical sensor (110') may include a plurality of spectrophotometers. As a non-limiting example, the optical sensor (110') may include three spectrophotometers. In this case, one spectrophotometer may calculate the brightness of the center portion (A1C) of the first active material layer (A1), and the other two spectrophotometers may calculate the brightness of the side portion (A1S) of the first active material layer (A1).

[0075] Generally, the side portions of the active material layer dry faster than the center portion, and excessive drying of the side portions can lead to the exposure of the current collector. Such exposure of the current collector can cause cracks in the electrode. Some embodiments are designed taking into account this drying pattern of the active material layer.

[0076] The fact that the brightness of the center portion (A1C) of the first active material layer (A1) is lower than the above reference value means that the degree of drying of the first active material layer (A1) is insufficient. The fact that the brightness of the side portion (A1S) of the first active material layer (A1) is higher than the above reference value means that the drying of the side portion (A1S) of the first active material layer (A1) has been excessive. This is because when the current collector (B) is exposed at the side portion (A1S) of the first active material layer (A1), the reflectivity of the side portion (A1S) of the first active material layer (A1) increases due to the current collector (B), thereby increasing the brightness of the side portion (A1S) of the first active material layer (A1).

[0077] The above reference value may be determined from the average of the lightness values ​​of the active material layers where the degree of drying is judged to be appropriate. In some embodiments, the above reference value may be set to the same value as the average of the lightness values ​​of the active material layers where the degree of drying is judged to be appropriate. In some embodiments, the above reference value may be set to about 98% to about 102% of the average value of the lightness values ​​of the active material layers where the degree of drying is judged to be appropriate, taking into account process error.

[0078] In some embodiments, the electrode drying degree measuring device (100) may include a transmitting unit (120) configured to transmit a defect signal to a display device (200) or a control device (300) if the brightness of the center portion (A1C) of the first active material layer (A1) is lower than a first reference value or the brightness of the side portion (A1S) of the first active material layer (A1) is higher than a second reference value. In some embodiments, the first reference value may be set to approximately 98% of the average value of the brightness values ​​of the active material layers for which the drying degree is judged to be appropriate, taking into account process error. In some embodiments, the second reference value may be set to approximately 102% of the average value of the brightness values ​​of the active material layers for which the drying degree is judged to be appropriate, taking into account process error.

[0079]

[0080] When the transmitting unit (120) transmits a fault signal to the display device (200), the display device (200) can display an alarm such as sound and light so that the operator can recognize that the drying of the first active material layer (A1) is faulty.

[0081] When the transmitter (120) transmits a fault signal to the control device (300), the control device (300) can stop the operation of the rollers (R1~R11), the top surface coating device (C1), the top surface drying device (D1), the back surface coating device (C2), and the back surface drying device (D2).

[0082]

[0083] Another aspect of the present invention relates to an electrode coating device.

[0084] FIG. 2 is a drawing for explaining the location of an electrode drying degree measuring device according to some embodiments and an electrode coating device according to some embodiments.

[0085] In some embodiments, the electrode coating device (10) may include the aforementioned electrode drying degree measuring device (100) located between the top surface drying device (D1) and the back surface coating device (C2) based on the machine direction (MD) of the top surface drying device (D1), the back surface coating device (C2), and the current collector (B).

[0086] In some embodiments, the electrode coating device (10) may additionally include a top surface coating device (C1) and a back surface drying device (D2).

[0087] In some embodiments, the electrode coating device (10) may additionally include a plurality of rollers (R1 to R11).

[0088] In some embodiments, the top surface coating device (C1), the top surface drying device (D1), the electrode drying degree measuring device (100), the back surface coating device (C2), and the back surface drying device (D2) may be arranged sequentially based on the MD (machine direction) of the current collector (B).

[0089] The descriptions for the top surface coating device (C1), the top surface drying device (D1), the electrode drying degree measuring device (100), the back surface coating device (C2), and the back surface drying device (D2) are identical to those previously described, so redundant descriptions thereof are omitted.

[0090]

[0091] The above description is merely for illustrative purposes only. The scope of the present invention shall be interpreted by the claims, and all technical ideas within the scope equivalent or equivalent thereto shall be interpreted as being included within the scope of the present invention.

[0092]

[0093] [Explanation of the symbol]

[0094] 10: Electrode coating device

[0095] A1: First active material layer

[0096] A2: Second active material layer

[0097] B: The whole house

[0098] C1: Top surface coating device

[0099] C2: Back surface coating device

[0100] D1: Tower surface drying device

[0101] D2: White surface drying device

[0102] R1~R11: Multiple rollers

[0103] S1: First slurry

[0104] S2: Second slurry

[0105] 100: Electrode drying degree measuring device

[0106] 110: Image sensor

[0107] 110': Optical sensor

[0108] 120: Transmitter

[0109] 200: Display device

[0110] 300: Control unit

[0111] A1C: Center Department

[0112] A1S: Side section

Claims

1. Located behind the MD (machine direction) of the current collector, relative to the top surface drying device configured to dry the slurry coated on the top surface of the current collector. An electrode drying degree measuring device configured to measure the degree of drying of the center and side portions of the active material layer dried by the above-mentioned top surface drying device.

2. In Claim 1, The above electrode drying degree measuring device The degree of dryness of the center portion of the active material layer is measured from the brightness of the center portion of the active material layer, and An electrode drying degree measuring device configured to measure the degree of drying of the side portion of the active material layer from the brightness of the side portion of the active material layer.

3. In Claim 2, The electrode drying degree measuring device described above includes an image sensor configured to calculate the brightness of the center portion and the side portion of the active material layer, respectively, from an image of the active material layer.

4. In Claim 2, The electrode drying degree measuring device described above includes an optical sensor configured to irradiate light onto the active material layer and analyze the light reflected from the active material layer to calculate the brightness of the center portion and the side portion of the active material layer, respectively.

5. In Claim 2, The electrode drying degree measuring device described above includes a transmitting unit configured to transmit a defect signal to a display device when the brightness of the center portion of the active material layer is lower than a reference value or the brightness of the side portion of the active material layer is higher than the reference value.

6. In Claim 2, The electrode drying degree measuring device described above includes a transmitter configured to transmit a defect signal to a control device if the brightness of the center portion of the active material layer is lower than the non-drying reference value or if the brightness of the side portion of the active material layer is higher than the over-drying reference value.

7. A top surface drying device configured to dry a first slurry coated on the top surface of the entire current collector; A back surface coating device configured to coat a second slurry on the back surface of the above-mentioned current collector; and An electrode drying degree measuring device according to claim 1 located between the top surface drying device and the back surface coating device; Electrode coating device including 8. In Claim 7, The above coating device A tower surface coating device configured to coat a first slurry on the tower surface of the above-mentioned current collector; and a back surface drying device configured to dry a second slurry coated on the back surface of the above-mentioned current collector; An electrode coating device additionally comprising

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