Apparatus and method for drying electrode substrates including a screen for distributing flow

Abstract

The present technology relates to an apparatus and method for drying an electrode substrate including a mesh for distributing a flow rate of hot air, and according to the present invention, the electrode substrate can be uniformly dried in a width direction.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0154531, filed on November 18, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an apparatus and method for drying an electrode substrate including a screen for distributing the flow rate of hot air. Background Art

[0003] Recently, with the development of technology and the increase in demand for mobile devices, the demand for secondary batteries as energy sources is rapidly increasing.

[0004] Depending on the type of external device, the secondary battery can be used in the form of a single battery cell or in the form of a module in which a plurality of unit batteries are electrically connected. For example, small devices such as mobile phones can operate for a predetermined time with the output and capacity of one battery cell, but medium and large devices such as notebook computers, portable DVDs, personal computers, electric vehicles, and hybrid electric vehicles require a battery module including a plurality of battery cells due to output and capacity requirements.

[0005] In addition, the secondary battery is manufactured through a process of assembling battery cells and a process of activating the battery. At this time, the activation process of the battery is performed as the charging / discharging device applies a desired current to the target battery cell.

[0006] Figure 1 and Figure 2 Shown are curves obtained by measuring the surface temperature of an electrode substrate immediately after drying the electrode substrate after coating the top and back of the electrode substrate when a conventional electrode substrate drying method is applied.

[0007] Reference Figure 1 After the mixture layer is formed on one surface of the electrode substrate, the surface temperature of the electrode substrate is measured in the width direction (TD direction) at a time point after a drying process is performed in a conventional scheme. Figure 1 In the embodiment of the present invention, the temperature of the center portion of the electrode substrate is about 24° C. At this point, the temperature of the two side portions (DS and OS) is about 28° C. Figure 1 In the electrode substrate, the temperature difference between the central portion and the side portion is about 4°C.

[0008] In addition, refer to Figure 2After forming a mixture layer on one surface of an electrode substrate, drying the electrode substrate, and then performing a back coating process to form a mixture layer on another surface of the electrode substrate, after performing the drying process in a conventional scheme, the surface temperature of the electrode substrate was measured in the width direction (TD direction). Figure 2 In the embodiment of the present invention, the temperature of the center portion of the electrode substrate is about 40.7° C. At this point, the temperature of the two side portions (DS and OS) is about 43.3° C. Figure 2 In the electrode substrate, the temperature difference between the central portion and the side portion is about 3°C.

[0009] like Figure 1 and Figure 2 As shown in , when the electrode substrate is dried according to a conventional scheme, a temperature difference of 2 to 6° C. is shown in the width direction of the electrode substrate. This temperature difference reduces the adhesion between the electrode substrate and the mixture layer and causes cracks on the surface of the electrode due to excessive drying of the side of the electrode substrate.

[0010] Therefore, a technology for uniformly drying an electrode substrate without much modification of conventional equipment is required. Summary of the invention

[0011] Technical issues

[0012] The present invention is directed to solving at least some of the above problems.For example, one aspect of the present invention provides an apparatus and method for drying an electrode substrate including a screen for distributing a flow rate of hot air.

[0013] Technical Solution

[0014] The present invention provides an apparatus for drying an electrode substrate. In one example, the apparatus for drying an electrode substrate according to the present invention includes: a drying furnace that dries an electrode substrate conveyed along a conveying line; a hot air discharge unit that discharges hot air through a nozzle located at an upper portion of the drying furnace; and a screen that is located on a hot air discharge route of the hot air discharge unit and controls the hot air discharged from the nozzle. In addition, the screen is divided into a central portion and a side portion based on the length in the width direction of the electrode substrate, and satisfies the following condition 1.

[0015] [Condition 1]

[0016] D center >1.3xD side

[0017] Here, D center represents an average opening ratio in the central portion based on the length in the width direction of the electrode substrate, and

[0018] D side It represents the average opening ratio of the side portions formed on both sides of the central portion.

[0019] In one example, in the apparatus for drying an electrode substrate according to the present invention, a formation ratio (C:S) of the central portion (C) to the side portions (S) formed on both sides of the central portion and having a closed structure is in the range of 15-60:40-85.

[0020] In another example, in the apparatus for drying an electrode substrate according to the present invention, a wind speed of hot air applied to each region of the electrode substrate corresponding to the mesh satisfies the following Condition 2.

[0021] [Condition 2]

[0022] 1.5≤(WS center ) / (WS side )≤10

[0023] Here, WS center represents the wind speed (m / s) of the hot air applied to the electrode substrate corresponding to the central portion of the mesh, and

[0024] WS side denotes an average wind speed (m / s) of the hot air applied to the electrode substrate corresponding to the side portion of the mesh.

[0025] In one example, the central portion has an open structure, and the side portions have a closed structure.

[0026] In another example, the central portion includes an open area, and boundary areas formed at both sides of the open area and having a plurality of through holes, and the side portions have a closed structure.

[0027] In another example, each of the central portion and the side portion has a plurality of through holes, and each of the through holes formed in the central portion and the side portion satisfies the following Condition 3.

[0028] [Condition 3]

[0029] 4≤D1 / D2≤20

[0030] Here, D1 represents an average diameter of through holes formed in the central portion, and D2 represents an average diameter of through holes formed in the side portions.

[0031] In a specific example, an average diameter D1 of the through holes formed in the central portion is in the range of 9 to 20 mm.

[0032] In a specific example, a diameter of the through hole decreases continuously or sequentially in a direction from the central portion toward the side portion.

[0033] In one example, in the apparatus for drying an electrode substrate according to the present invention, the average opening ratio (D center ) is greater than or equal to 35%.

[0034] In one example, the hot air discharge unit includes: an inlet supplying hot air; and a blower blowing the hot air supplied through the inlet.

[0035] In another example, the apparatus for drying an electrode substrate according to the present invention further includes a temperature sensor measuring a surface temperature of the target electrode substrate.

[0036] In addition, the present invention provides a method for drying an electrode substrate using the above-mentioned apparatus for drying an electrode substrate. In one example, the method for drying an electrode substrate according to the present invention includes: drying the electrode substrate conveyed along a conveying line by using the above-mentioned apparatus.

[0037] In a specific example, during the drying process of the electrode substrate, the electrode substrate has a structure in which a mixture layer is coated on one surface of a current collector, and hot air is applied to the surface of the current collector coated with the mixture layer, or the electrode substrate has a structure in which a mixture layer is coated on both surfaces of the current collector, and hot air is applied to the surface of the current collector coated with the mixture layer.

[0038] In a specific example, the electrode substrate is an electrode substrate for a pouch-type secondary battery.

[0039] Beneficial Effects

[0040] According to the apparatus and method for drying an electrode substrate of the present invention, the electrode substrate can be dried uniformly in the width direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Shown is a curve obtained by measuring the surface temperature of the electrode substrate immediately after drying the electrode substrate after coating the top of the electrode substrate when a conventional electrode substrate drying method is applied.

[0042] Figure 2 Shown is a curve obtained by measuring the surface temperature of the electrode substrate immediately after drying the electrode substrate after coating the back of the electrode substrate when a conventional electrode substrate drying method is applied.

[0043] Figures 3 to 5 Each of them is a schematic diagram illustrating a screen according to an embodiment of the present invention.

[0044] Figure 6 is a curve obtained by measuring the surface temperature of the electrode substrate immediately after drying the electrode substrate after coating the top of the electrode substrate when the electrode substrate drying method according to one embodiment of the present invention is applied.

[0045] Figure 7 is a curve obtained by measuring the surface temperature of the electrode substrate immediately after drying the electrode substrate after coating the back of the electrode substrate when the electrode substrate drying method according to one embodiment of the present invention is applied. DETAILED DESCRIPTION

[0046] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The terms and words used in this specification and claims should not be interpreted as limited to common terms or dictionary terms, and the inventors can appropriately define the concepts of the terms in order to best describe their inventions. The terms and words should be interpreted as meanings and concepts consistent with the technical concept of the present invention.

[0047] In the present application, it should be understood that terms such as "including" or "having" are intended to indicate that the described features, quantities, steps, operations, components, parts or combinations thereof are present in the present application, and they do not preclude the possibility of the presence or addition of one or more other features or quantities, steps, operations, components, parts or combinations thereof. In addition, when a part such as a layer, a film, a region, a plate, etc. is referred to as being "on" another part, this includes not only the case where the part is "directly" "on" the other part, but also the case where other parts are inserted between the part and the other part. On the other hand, when a part such as a layer, a film, a region, a plate, etc. is referred to as being "under" another part, this includes not only the case where the part is "directly" "under" the other part, but also the case where other parts are inserted between the part and the other part. In addition, to be set "on" in the present application may include the case where it is set at the bottom as well as the top.

[0048] The present invention relates to an apparatus for drying an electrode substrate, which applies a screen for distributing the flow rate of hot air. In one example, the apparatus for drying an electrode substrate according to the present invention includes: a drying furnace that dries an electrode substrate conveyed along a conveying line; a hot air discharge unit that discharges hot air through a nozzle located at an upper portion of the drying furnace; and a screen that is located on a hot air discharge route of the hot air discharge unit and controls the hot air discharged from the nozzle. In addition, the screen is divided into a central portion and a side portion based on the length in the width direction of the electrode substrate, and the following condition 1 is satisfied.

[0049] [Condition 1]

[0050] D center >1.3xDside ,

[0051] Here, D center represents the average aperture ratio in the central region based on the length in the width direction of the electrode substrate, and D side It represents the average opening ratio of the side portions formed on both sides of the central portion.

[0052] In the screen according to the present invention, the central portion has a relatively open structure, and the side portion has a relatively closed structure. The flow rate of hot air reaching the target electrode substrate is controlled by arranging the screen on the hot air discharge route of the hot air discharge unit. Generally, during the process of drying the electrode substrate using a drying furnace, the side portion is dried more quickly by the flow of hot air. In this way, the degree of drying of the central portion and the side portion of the electrode substrate becomes different, which reduces the adhesion between the current collector and the mixture layer, and causes cracks on the surface of the electrode substrate due to excessive drying of the side portion. In the present invention, the hot air is controlled to be concentrated on the central portion of the electrode substrate by the above-mentioned screen. Thus, by applying the device for drying the electrode substrate according to the present invention, the entire area of ​​the electrode substrate can be dried at a uniform speed.

[0053] The screen according to the present invention is located on the hot air discharge route of the hot air discharge unit and is arranged along the width direction (TD direction, Transverse Direction) of the target electrode substrate. The screen is divided into a central portion and two side portions. In one embodiment, the formation ratio (C:S) of the central portion (C) and the side portions (S) formed on both sides of the central portion and having a closed structure is in the range of 15 to 60:40 to 85. Specifically, the formation ratio (C:S) is in the range of 15 to 55:45 to 85, 20 to 50:50 to 80, or 20 to 40:60 to 80. The formation ratio is determined in consideration of uniformly drying the electrode substrate by hot air distribution. If the formation of the side portion is too large, the drying efficiency of the electrode substrate is reduced, and if the formation of the central portion is too large, the flow distribution effect based on the formation of the screen is reduced.

[0054] The formation of the side portion means the sum of the formation areas of the side portions formed on both sides with the central portion as the reference. In addition, the formation ratio is calculated based on the length of each formed area. For example, the total length (TD direction) of the screen is 1400 mm, the length of the central portion is 300 mm or 500 mm, and the side portions on both sides of the central portion have the same length.

[0055] In one example, in the apparatus for drying an electrode substrate according to the present invention, the wind speed of the hot air applied to each area of ​​the electrode substrate corresponding to the mesh satisfies the following Condition 2.

[0056] [Condition 2]

[0057] 1.5≤(WS center ) / (WS side )≤10

[0058] Here, WS center represents the wind speed (m / s) of the hot air applied to the electrode substrate corresponding to the central area of ​​the mesh, and WS side It represents the average wind speed (m / s) of the hot air applied to the electrode substrate corresponding to the side area of ​​the mesh.

[0059] In the present invention, by using the above-mentioned mesh, the wind speed (WS) of the hot air applied to the central portion of the electrode substrate is center ) is controlled to become the wind speed (WS) of the hot air applied to the side of the electrode substrate side ) is 1.5 to 10 times of the wind speed of the electrode substrate. Specifically, the ratio of the wind speed defined in the above condition 2 is in the range of 1.5 to 8, 1.5 to 4, 3 to 8, 2 to 6, or 1.8 to 5.7. For example, when the hot air is discharged at 1000 rpm, the wind speed (WS) of the hot air applied to the central portion of the electrode substrate is center ) may be 0.94 m / s, and the wind speed (WS) of the hot air applied to the side of the electrode substrate may be 0.94 m / s. side ) can be controlled to be approximately 0.20m / s.

[0060] In one example, the central portion of the mesh has an open structure, and the side portions of the mesh have a closed structure. Thus, the supplied hot air is guided through the open central portion to be supplied to the electrode substrate.

[0061] In another embodiment, the screen comprises a central portion and a side portion. The central portion comprises an open area and a border area formed on both sides of the open area and having a plurality of through holes. The side portion has a closed structure. Here, the central portion has an open structure, and a plurality of through holes are formed in the border between the central portion and the side portion. For example, the border has a plurality of holes with an average diameter of 5 to 15 mm.

[0062] In another example, each of the central portion and the side portion has a plurality of through holes, and each of the through holes formed in the central portion and the side portion satisfies the following Condition 3.

[0063] [Condition 3]

[0064] 4≤D1 / D2≤20

[0065] Here, D1 represents an average diameter of through holes formed in the central portion, and D2 represents an average diameter of through holes formed in the side portions.

[0066] The screen has through holes on the front surface. The diameter of each through hole in the central portion is larger, and the diameter of each through hole in the side portion is smaller. In a specific example, the average diameter D1 of the through holes formed in the central portion is in the range of 9 to 20 mm. For example, the average diameter of the through holes in the central portion is in the range of 9 to 20 mm, 9 to 15 mm, or 10 to 12 mm, and the average diameter of the through holes in the side portion is in the range of 4 to 11 mm, 5 to 10.5 mm, or 6 to 10 mm.

[0067] In another specific example, the diameter of the through hole of the screen is continuously or sequentially reduced in the direction from the central part toward the side part. Thus, a large amount of hot air is guided to flow to the central part via the screen, while a relatively small amount of hot air is guided to flow to the side part. In addition, a rapid change in the flow rate of hot air between the central part and the side part according to the formation of the screen can be prevented.

[0068] In one example, in the apparatus for drying an electrode substrate according to the present invention, the average opening ratio (D center ) is greater than or equal to 35%. Specifically, the average opening ratio (D center ) is in the range of 35% to 100%, 50% to 99%, or 50% to 75%. When the average opening ratio of the central portion is 100%, it means that the central portion is completely open. In addition, the average opening ratio of the side portion (D side ) is controlled to be smaller than the average opening ratio (D center Specifically, the average opening ratio (D side ) is less than or equal to 70%, less than or equal to 50%, in the range of 5% to 70%, or in the range of 15% to 50%. When the average opening ratio of the side portion is 0%, it means that the side portion is completely closed.

[0069] In one example, the hot air discharge unit includes: an inlet for supplying hot air; and a blower for blowing the hot air supplied through the inlet. The hot air heated at the outside is supplied through the inlet, and the supplied hot air flows to one side of the electrode substrate through the blower.

[0070] In another example, the apparatus for drying an electrode substrate according to the present invention further includes a temperature sensor for measuring the surface temperature of the target electrode substrate. The temperature sensor is used to check the drying state of the electrode substrate and the temperature uniformity of each area of ​​the electrode substrate. A contact sensor can be used as the temperature sensor, but a non-contact sensor is preferred in consideration of process efficiency, etc. For example, the temperature sensor may include a processing unit that calculates the surface temperature of the electrode substrate based on a thermal imaging camera and / or an image taken by the thermal imaging camera.

[0071] In addition, the present invention provides a method for drying an electrode substrate using the above-mentioned apparatus for drying an electrode substrate. In one example, the method for drying an electrode substrate according to the present invention includes: drying the electrode substrate conveyed along a conveying line by using the above-mentioned apparatus.

[0072] In one embodiment, during the drying process of the electrode substrate, the electrode substrate has a structure in which the mixture layer is coated on one surface of the current collector, that is, a top coating structure, and drying is performed by applying hot air on the surface of the current collector on which the mixture layer is coated. Alternatively, the electrode substrate has a structure in which the mixture layer is coated on both surfaces of the current collector, that is, a back coating structure, and then drying is performed by applying hot air on the surface of the coated mixture layer. For example, in the case where the electrode substrate has a back coating structure, it may be the case that the electrode slurry is discharged to the other surface of the current collector that has undergone the top coating and drying process, thereby forming a coating layer.

[0073] In a specific example, the electrode substrate is an electrode substrate for a pouch-type secondary battery. For example, the pouch-type secondary battery is a lithium secondary battery. In addition, the electrode substrate may be a positive electrode substrate or a negative electrode substrate.

[0074] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0075] Hereinafter, the present invention will be described in more detail by way of the accompanying drawings, etc. However, the embodiments described in the specification and the configurations described in the accompanying drawings are only the most preferred embodiments of the present invention and do not represent all technical ideas of the present invention. It should be understood that various equivalents and variations may exist to replace them.

[0076] [First embodiment]

[0077] Figure 3 Schematic diagram showing a screen according to one embodiment of the present invention. Figure 3 , the screen 100 includes: a central portion 110 having an open structure; and side portions 121 and 122 having a closed structure. The total width of the screen 100 is about 1400 mm, the width of the central portion 110 is about 300 mm, and each of the side portions 121 and 122 is about 550 mm. The hot air discharged from the hot air discharge unit is provided to the electrode substrate via the screen 100 through the open central portion 110. Therefore, the phenomenon that the side area in the width direction of the electrode substrate is dried first can be prevented.

[0078] The measurements are applied to Figure 3 The wind speed of the hot air in each area of ​​the electrode substrate corresponding to the screen 100 shown in FIG. Figure 3The wind speed of the hot air is measured at the surface of each area of ​​each corresponding electrode substrate of points (A-1) to (A-3). The air flow rate of the hot air provided is expressed in RPM, and the wind speed of each measurement position is expressed in m / s. The wind speed of the hot air is measured using Velocicalc 9565P of TSI. The results are shown in Table 1.

[0079] [Table 1]

[0080]

[0081] Referring to Table 1, under the condition of 1000 RPM, the wind speed at the point corresponding to the center portion is 0.94 m / s, which corresponds to about 4.7 times the wind speed of 0.20 m / s at the point corresponding to the side portion.

[0082] [Second embodiment]

[0083] Figure 4 Schematic diagram showing a screen according to another embodiment of the present invention. Figure 4 , the screen 200 includes: a central portion 210 having a partially open structure; and two side portions 221 and 222 having a closed structure. Boundary portions 211 and 212 having a plurality of through holes are formed on both sides of the central portion 210. The total width of the screen 200 is about 1400 mm, the width of the central portion 210 is about 500 mm, and each of the side portions 221 and 222 is about 450 mm. In addition, the width of the fully open area of ​​the central portion 210 is 300 mm, and the width of each of the boundary portions 211 and 212 having through holes and partially open is about 100 mm. The hot air discharged from the hot air discharge unit is provided to the electrode substrate via the screen 200 through the open central portion 210.

[0084] The measurements are applied to Figure 4 The wind speed of the hot air in each area of ​​the electrode substrate corresponding to the screen 200 shown in FIG. Figure 4 The wind speed of the hot air is measured at the surface of each area of ​​each corresponding electrode substrate of points (B-1) to (B-3). The air flow rate of the hot air provided is expressed in RPM, and the wind speed of each measurement position is expressed in m / s. The wind speed of the hot air is measured using Velocicalc 9565P of TSI. The results are shown in Table 2.

[0085] [Table 2]

[0086]

[0087]

[0088] Referring to Table 2, under the condition of 1000RPM, the wind speed at the point corresponding to the central portion is 1.90m / s, which corresponds to about 6.7 times the wind speed of 0.29m / s at the point corresponding to the side portion. Compared with the results of Table 1, the results of Table 2 show that by forming the area with through holes on one side of the central portion, the overall wind speed of the hot air increases, and the wind speed difference between the central portion and the side portion also increases.

[0089] [Third Embodiment]

[0090] Figure 5 Schematic diagram showing a screen according to another embodiment of the present invention. Figure 5 , the screen 300 includes two side portions having through holes with a smaller diameter than the through hole formed in the central portion. The total width of the screen 300 is 1400 mm. The diameter of the through hole formed in the center of the central portion is about 12 mm, and the diameter of the through hole formed at the end of the side portion is about 6 mm. Figure 5 In the embodiment, the diameter of each through hole gradually decreases from the center of the central portion toward the two side portions.

[0091] The measurements are applied to Figure 5 The wind speed of the hot air in each area of ​​the electrode substrate corresponding to the screen shown in FIG. Figure 5 The wind speed of the hot air is measured at the surface of each area of ​​each corresponding electrode substrate of points (C-1) to (C-7). The air flow rate of the hot air provided is expressed in RPM, and the wind speed of each measurement position is expressed in m / s. The wind speed of the hot air is measured using Velocicalc9565P of TSI. The results are shown in Table 3.

[0092] [Table 3]

[0093]

[0094] In Table 3, (C-1) is a region where a through hole with a diameter of 6 mm is formed, (C-2) is a region where a through hole with a diameter of 7 mm is formed, (C-3) is a region where a through hole with a diameter of 8 mm is formed, (C-4) is a region where a through hole with a diameter of 9 mm is formed, (C-5) is a region where a through hole with a diameter of 10.5 mm is formed, (C-6) is a region where a through hole with a diameter of 11 mm is formed, and (C-7) is a region where a through hole with a diameter of 12 mm is formed.

[0095] Reference Figure 3 , under the condition of 1000RPM, the wind speed gradually increases in the direction from the point (C-1) corresponding to the side to the point (C-7) corresponding to the center. However, at point (C-5), the wind speed is slightly reduced, but this is considered to be due to the vortex effect in the drying furnace.

[0096] [Fourth Embodiment]

[0097] Figure 6 and Figure 7 is a curve obtained by measuring the surface temperature of the electrode substrate immediately after drying the electrode substrate after coating the top and back of the electrode substrate when the electrode substrate drying method according to one embodiment of the present invention is applied.

[0098] Reference Figure 6 After performing a top coating process of forming a mixture layer on one surface of the electrode substrate, Figure 4 The surface temperature of the electrode substrate was measured in the width direction (TD direction) at a time point after the mesh shown in FIG. Figure 6 In the embodiment, the average temperature of the center portion of the electrode substrate is about 28.5°C. In this regard, the average temperature of the left side portion (DS) is 29.3°C, and the average temperature of the right side portion (OS) is 30.2°C. Figure 6 In the electrode substrate, the temperature difference between the central portion and the side portion is in the range of 0.8 to 1.7°C.

[0099] In addition, refer to Figure 7 , after coating the back of the electrode substrate, by applying Figure 4 The surface temperature of the electrode substrate was measured in the width direction (TD direction) at a time point after the mesh shown in FIG. Figure 7 In the embodiment, the average temperature of the center portion of the electrode substrate is about 45.1°C. In this regard, the average temperature of the left side portion (DS) is 45.6°C, and the average temperature of the right side portion (OS) is 45.9°C. Figure 7 In the electrode substrate, the temperature difference between the central portion and the side portion is less than or equal to 0.8°C.

[0100] Reference Figure 6 and Figure 7 , when the drying scheme according to the present invention is applied, the temperature in the width direction of the electrode substrate is controlled at a very uniform level.

[0101] The above description is only an example of the technical concept of the present invention, and those skilled in the art to which the present invention belongs may make various modifications and changes without departing from the essential features of the present invention. Therefore, the drawings disclosed in the present invention are not intended to limit the technical concept of the present invention, but to describe the present invention, and the scope of the technical concept of the present invention is not limited by these drawings. The scope of protection of the present invention shall be interpreted by the following claims, and all technical concepts within the scope equivalent thereto shall be interpreted as included in the scope of the present invention.

[0102] [Explanation of Reference Numbers]

[0103] 100, 200, 300: Screen

[0104] 110, 210: Central

[0105] 211, 212: Boundary

[0106] 121, 131, 221, 222: Side

[0107] (A-1), (A-2), (A-3), (B-1), (B-2), (B-3), (C-1), (C-2), (C-3), (C-4), (C-5), (C-6), (C-7): Hot air velocity measurement points.

Claims

1. A device for drying an electrode substrate, the device comprising: a drying furnace for drying the electrode substrate conveyed along the conveying line; a hot air discharge unit that discharges hot air through a nozzle located at an upper portion of the drying furnace; and a screen which is located on a hot air discharge route of the hot air discharge unit and controls the hot air discharged from the nozzle, The mesh is divided into a central portion and a side portion based on the length in the width direction of the electrode substrate, and satisfies the following condition 1: [Condition 1] D center >1.3xD side , Where D center represents an average opening ratio in the central portion based on the length in the width direction of the electrode substrate, and Where D side It represents the average opening ratio of the side portions formed on both sides of the central portion.

2. The apparatus according to claim 1, wherein a formation ratio (C:S) of the central portion (C) to the side portions (S) formed on both sides of the central portion and having a closed structure is in the range of 15-60:40-85.

3. The apparatus according to claim 1, wherein the wind speed of the hot air applied to each area of ​​the electrode substrate corresponding to the mesh satisfies the following condition 2: [Condition 2] 1.5≤(WS center ) / (WS side )≤10, WS center represents the wind speed (m / s) of the hot air applied to the electrode substrate corresponding to the central portion of the mesh, and WS side denotes an average wind speed (m / s) of the hot air applied to the electrode substrate corresponding to the side portion of the mesh. The apparatus according to claim 1 , wherein the central portion has an open structure and the side portions have a closed structure.

5. The apparatus according to claim 1, wherein the central portion includes an open area, and boundary areas formed on both sides of the open area and having a plurality of through holes, and The side portion has a closed structure.

6. The apparatus of claim 1, wherein each of the central portion and the side portions has a plurality of through holes, and The through holes formed in the central portion and the side portions satisfy the following condition 3: [Condition 3] 4≤D1 / D2≤20, wherein D1 represents the average diameter of the through holes formed in the central portion, and Wherein D2 represents the average diameter of the through holes formed in the side portion. 7 . The apparatus according to claim 6 , wherein an average diameter D1 of the through-holes formed in the central portion is in the range of 9 to 20 mm. 8 . The apparatus according to claim 6 , wherein a diameter of the through hole decreases continuously or sequentially in a direction from the central portion toward the side portion.

9. The device according to claim 1, wherein the average opening ratio (D center ) is greater than or equal to 35%.

10. The apparatus according to claim 1, wherein the hot air discharge unit comprises: an inlet for supplying hot air; and a blower that blows the hot air supplied through the inlet.

11. The apparatus of claim 1, further comprising a temperature sensor measuring a surface temperature of the target electrode substrate.

12. A method for drying an electrode substrate, the method comprising: The electrode substrate conveyed along the conveying line is dried by using the apparatus according to any one of claims 1 to 11.

13. The method according to claim 12, wherein during the drying process of the electrode substrate, the electrode substrate has a structure in which a mixture layer is coated on one surface of a current collector, and hot air is applied to the surface of the current collector coated with the mixture layer, or the electrode substrate has a structure in which a mixture layer is coated on both surfaces of a current collector, and hot air is applied to the surface of the current collector coated with the mixture layer. 14 . The method according to claim 12 , wherein the electrode substrate is an electrode substrate for a pouch type secondary battery.

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