[One]Cross-Citation with Related Application(s)
[2]This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0056451 dated May 14, 2019, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
The present invention relates to a slot die coating apparatus comprising an air vent.
background
[4]
Recently, an increase in the price of an energy source due to the depletion of fossil fuels, an interest in environmental pollution is amplified, and the demand for an eco-friendly alternative energy source has become an indispensable factor for future life. Accordingly, research on various power generation technologies such as nuclear power, solar power, wind power, and tidal power continues, and power storage devices for using the generated energy more efficiently are also of great interest.
[5]
Moreover, as technology development and demand for mobile devices and battery vehicles increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, a lot of research on batteries capable of meeting various needs is being conducted. In particular, in terms of materials, there is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries having advantages such as high energy density, discharge voltage, and output stability.
[6]
The secondary battery includes an electrode assembly having a structure in which a positive electrode, a negative electrode, and a separator interposed between the positive and negative electrodes are stacked, and the battery is manufactured by accommodating these electrode assemblies in a pouch case, a cylindrical can, and a prismatic case depending on the purpose of use. do.
[7]
The positive electrode and the negative electrode are prepared by coating and drying the positive electrode slurry and the negative electrode slurry on an electrode current collector made of aluminum foil and copper foil, respectively. In order to make the charging/discharging characteristics of the secondary battery uniform, the positive electrode active material slurry and the negative electrode active material slurry should be uniformly coated on the current collector, and for this purpose, a slot die coating process is typically performed.
[8]
1 is a vertical cross-sectional view showing a conventional slot die coating apparatus used in a single-layer active material coating process. 2 is a vertical cross-sectional view showing a conventional slot die coating apparatus used in a multi-layer active material coating process.
[9]
The slot die coating apparatus 10 includes a slot die 11 and a coating roller 12 through which the electrode active material slurry is discharged. The slot die 11 includes two die blocks 11a and 12a, and an outlet 13 through which an electrode active material slurry (not shown) is discharged between the first die block 11a and the second die block 11b. ) is formed. As the coating roller 12 rotates, the electrode active material slurry discharged from the discharge port 13 is applied to one surface of the current collector 30 .
[10]
In some cases, an electrode active material layer constituting another layer may be additionally applied on the electrode active material layer constituting one layer to form an electrode active material layer comprising two layers. In order to form the electrode active material layer composed of two layers as described above, a slot die 21 including four die blocks 21a , 21b , 21c and 21d is used as shown in FIG. 2 . The slot die 21 simultaneously discharges the electrode active material slurry through the two outlets 23 and 24 formed between the adjacent die blocks 21a, 21b, 21c, and 21d. The electrode active material slurry may be continuously applied.
[11]
3 is a photograph showing the uncoated area contamination phenomenon that occurs when intermittent coating is performed using the slot die coating apparatus of FIGS. 1 and 2 .
[12]
1 to 3 , when the full width intermittent coating is performed using the slot die coating apparatuses 10 and 20 , the uncoated area 31 to which the electrode active material slurry is not applied is formed on the current collector 30 . At this time, when bubbles are present in the electrode active material slurry, the bubbles are released from the outlets 13 , 23 , and 24 in the section where the uncoated region 31 is formed and burst. At this time, a contamination phenomenon in which the electrode active material slurry surrounding the air bubbles is partially applied to the uncoated area 31 like a spot pattern 40 occurs.
[13]
In the electrode active material coating process, since the discharge ports 13 , 23 , 24 and the collector 30 are generally formed with an interval d of 100 micrometers to 200 micrometers, the contamination phenomenon as described above even by fine air bubbles This happens.
[14]
Therefore, there is an urgent need to develop a slot die device having an improved structure capable of solving these problems.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[15]
An object of the present invention is to provide a slot die coating apparatus capable of preventing the uncoated region from being contaminated with the electrode active material slurry in the intermittent coating process of the electrode active material.
[16]
However, the problems to be solved by the embodiments of the present invention are not limited to the above-described problems and may be variously expanded within the scope of the technical idea included in the present invention.
means of solving the problem
[17]
A slot die coating apparatus according to an embodiment of the present invention is a slot die coating apparatus for coating an electrode active material slurry on an electrode current collector, a die including a coating roller, a lower discharge part through which the first electrode active material slurry is discharged, and the lower part and an upper die disposed on the die and including an upper outlet through which the second electrode active material slurry is discharged.
[18]
An upper air vent may be installed in the upper die, and a lower air vent may be installed in the lower die.
[19]
The upper die may include an upper first die, an upper second die, and an upper spacer.
[20]
The upper discharge part may be formed by sequentially coupling the upper first die, the upper spacer, and the upper second die.
[21]
An upper slurry receiving part may be formed in the upper second die.
[22]
The upper slurry receiving part may communicate with the upper discharge part.
[23]
The upper air vent may pass through the upper first die to communicate with the upper slurry receiving part.
[24]
The lower die may include a lower first die, a lower second die, and a lower spacer.
[25]
The lower discharge part may be formed by sequentially coupling the lower first die, the lower spacer, and the lower second die.
[26]
A lower slurry receiving part may be formed in the lower second upper die.
[27]
The lower slurry receiving part may communicate with the lower discharge part.
[28]
The lower air vent may pass through the upper first die, the upper second die, and the lower first die to communicate with the lower slurry receiving part.
[29]
The lower air vent may be formed at a portion S where the lower slurry receiving part and the lower outlet part are connected.
[30]
The upper spacer may have a first opening and may be interposed only in the remaining portion except for one side of an edge region where the upper first die and the upper second die face each other.
[31]
The lower air vent may be installed through the upper spacer.
[32]
The upper air vent and/or the lower air vent may include a valve.
Effects of the Invention
[33]
As described above, in the slot die coating apparatus according to an embodiment of the present invention, by installing an air vent in the slot die, air bubbles included in the electrode active material slurry flowing into the discharge port can be removed.
Brief description of the drawing
[34]
1 is a vertical cross-sectional view showing a conventional slot die coating apparatus used in a single-layer active material coating process.
[35]
2 is a vertical cross-sectional view showing a conventional slot die coating apparatus used in a multi-layer active material coating process.
[36]
3 is a photograph showing the uncoated area contamination phenomenon that occurs when intermittent coating is performed using the slot die coating apparatus of FIGS. 1 and 2 .
[37]
4 is a schematic diagram showing a slot die coating apparatus according to an embodiment of the present invention.
[38]
FIG. 5 is a vertical cross-sectional view taken along the dotted line A of FIG. 4 when viewed from the direction C; FIG.
[39]
6 is a plan view illustrating the upper spacer of FIG. 5 .
[40]
FIG. 7 is a vertical cross-sectional view taken along a dotted line B of FIG. 4 when viewed from a direction C; FIG.
[41]
8 is a plan view illustrating the lower spacer of FIG. 7 .
[42]
9 is a plan view illustrating an upper spacer positioned on an upper second die.
[43]
10 is a plan view illustrating a lower spacer positioned on a lower second die.
[44]
11 is a plan view of the slot die of FIG. 4 ;
[45]
12 is a vertical cross-sectional view illustrating a modified example of FIG. 5 .
[46]
13 is a vertical cross-sectional view illustrating a modified example of FIG. 7 .
Modes for carrying out the invention
[47]
Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily carry out the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.
[48]
In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.
[49]
4 is a schematic diagram showing a slot die coating apparatus according to an embodiment of the present invention. FIG. 5 is a vertical cross-sectional view taken along the dotted line A of FIG. 4 when viewed from the direction C; FIG.
[50]
4 and 5, the slot die coating apparatus 100 includes a slot die 101, a coating roller 102 and an air vent (AIR VENT; 103). The slot die coating apparatus 100 is used for fixing coating for coating two electrode active material layers at the same time.
[51]
The slot die 101 includes an upper die 101A and a lower die 101B. The upper die 101A includes an upper first die 101A-1 , an upper second die 101A-2 , and an upper spare 123 . The upper second die 101A-2 may have an inclined structure in which a surface facing the lower first die 101B-1 has an angle of approximately 30 to 60 degrees with respect to the ground.
[52]
The upper second die 101A-2 may include an upper slurry receiving part 121 in the form of a groove having a predetermined depth on a surface facing the upper first die 101A-1. The upper slurry receiving part 121 may be connected to an externally installed upper slurry supply chamber (not shown) to continuously receive the first electrode active material slurry. The upper slurry receiving part 121 may include an upper slurry supply port 122 communicating with an upper slurry supply chamber (not shown).
[53]
When the first electrode active material slurry supplied through the upper slurry supply port 122 fills the upper slurry receiving part 121 , the first electrode active material slurry is transferred to the upper second die 101A-2 and the upper spacer 123 . And the coating roller 102 is moved in the installed direction through the upper discharge port 105 formed by sequential coupling of the upper first die 101A-1 and discharged to the outside. That is, the upper spacer 123 is interposed between the upper first die 101A-1 and the upper second die 101A-2, so that the upper first die 101A-1 and the upper second die 101A-2 are interposed. By forming a gap therebetween, a space in which the slurry of the first electrode active material supplied from the upper slurry receiving part 121 can be discharged is formed.
[54]
The upper first die 101A-1 is positioned on the upper second die 101A-2 and is coupled to the upper second die 101A-2 with the upper spacer 123 interposed therebetween. A surface of the upper first die 101A-1 facing the upper second die 101A-2 may be formed parallel to the ground.
[55]
An upper surface of the upper first die 101A-1 may be divided into two regions. The upper surface of the upper first die 101A-1 may include a flat portion 130 positioned relatively far from the upper discharge port 105 and an inclined portion 131 extending from the flat portion 130 . The flat portion 130 extends in a direction parallel to the ground, and the inclined portion 131 forms an angle of approximately 30 to 60 degrees with the flat portion 130 and is inclined downward.
[56]
The upper first die 101A-1 and the upper second die 101A-2 may be made of a metal material, and the upper first die 101A-1 and the upper second die 101A-2 are bolted. They may be fastened to each other by coupling or the like.
[57]
6 is a plan view illustrating the upper spacer of FIG. 5 .
[58]
4 to 6 , the upper spacer 123 may have a planar shape of approximately “C”. Accordingly, the upper spacer 123 has a first opening 123a formed on one side thereof, so that one side of the edges of the upper first die 101A-1 and the upper second die 101A-2 facing each other. It is included only in the rest of the parts except for . In addition, the upper first die 101A-1 and the upper second die 101A-2 are spaced apart from each other in the region where the first opening 123a is formed to form an upper discharge port 105 , and the upper discharge port 105 is formed. is in communication with the upper slurry receiving portion 121 .
[59]
The upper spacer 123 is a gap between the upper first die 101A-1 and the upper second die 101A-2, except for the area where the upper discharge hole 105 is formed, so that the first electrode active material slurry is formed. Since it functions as a gasket that prevents leakage, it is preferably made of a material having elasticity that can ensure sealing properties.
[60]
A through hole 123b through which the lower air vent 103B passes is formed in the upper spacer 123 . A detailed description of the lower air vent 103B will be described later.
[61]
FIG. 7 is a vertical cross-sectional view taken along a dotted line B of FIG. 4 when viewed from a direction C; FIG.
[62]
4 and 7 , the lower die 101B includes a lower first die 101B - 1 , a lower second die 101B - 2 , and a lower spare 113 . The lower second die 101B-2 is located at the lowest among the dies constituting the slot die 101, and the surface facing the lower first die 101B-1 is approximately 30 to 60 degrees with respect to the ground. The structure may be inclined to have an angle.
[63]
The lower second die 101B-2 may include a lower slurry receiving part 111 in the form of a groove having a predetermined depth on a surface facing the lower first die 101B-2. The lower slurry accommodating part 111 may be connected to a lower slurry supply chamber (not shown) installed outside to continuously receive the second electrode active material slurry. The lower slurry receiving part 111 may include a lower slurry supply port 112 communicating with the lower slurry supply chamber. The first electrode active material slurry and the second electrode active material slurry may be the same component or may be composed of different components depending on the use of the electrode to be manufactured.
[64]
When the second electrode active material slurry supplied through the slurry supply port 112 fills the lower slurry receiving part 111 , the second electrode active material slurry is formed by the lower second die 101B-2, the lower spacer 113 and It may be discharged to the outside through the lower discharge port 106 formed by sequential coupling of the lower first die 101B-1.
[65]
The lower first die 101B-1 is positioned on the lower second die 101B-2 and is coupled to the lower second die 101B-2 with the lower spacer 113 interposed therebetween. A surface of the lower first die 101B-1 and the lower second die 101B-2 facing each other may have a structure inclined to have an angle of approximately 30 to 60 degrees with respect to the ground.
[66]
The lower first die 101B-1 may have an upper surface facing the upper die 101A at an angle of approximately 30 degrees to 60 degrees with respect to the ground and obliquely inclined. As such, since the upper surface of the lower first die 101B-1 is inclined with respect to the ground, it can be matched with the upper die 101A having a lower surface having a shape corresponding to the upper surface of the lower first die 101B-1. have.
[67]
The lower first die 101B-1 and the lower second die 101B-2 may be made of a metal material, and may be coupled to each other by bolting or the like.
[68]
8 is a plan view illustrating the lower spacer of FIG. 7 .
[69]
7 and 8 , the lower spacer 113 is interposed between the lower first die 101B-1 and the lower second die 101B-2 to provide the lower first die 101B-1 and the lower portion. By forming a gap between the second dies 101B - 2 , a space through which the second electrode active material slurry supplied from the lower slurry receiving part 111 is discharged is formed.
[70]
The lower spacer 113 has a first opening 113a formed on one side thereof, so that the lower first die 101B-1 and the lower second die 101B-2 face each other among the edges of the lower spacer 113 . It is interposed only in the remaining part except for one side. In addition, the lower first die 101B-1 and the lower second die 101B-2 are spaced apart from each other in the region where the second opening 113a is formed to form a lower discharge port 106, and the lower discharge port 106 is formed. is in communication with the lower slurry receiving part 111 .
[71]
The lower spacer 113 has a gap between the lower first die 101B-1 and the lower second die 101B-2, except for the area where the lower discharge port 106 is formed, so that the second electrode active material slurry is formed. Since it functions as a gasket so as not to leak, it is preferable to be made of a material having elasticity that can ensure sealing properties.
[72]
5 and 6 , the air vent 103 includes an upper air vent 103A and a lower air vent 103B. The upper air vent 103A passes through the upper first die 101A-1 and communicates with the upper slurry receiving part 121 . Accordingly, before the first electrode active material slurry in the upper slurry receiving part 121 flows into the upper discharge port 105 , bubbles included in the first electrode active material slurry may be removed through the upper air vent 103A.
[73]
Since the upper discharge port 105 is formed in a direction parallel to the ground, no matter where the upper air vent 103A communicates with the upper slurry accommodating part 121 , the air bubbles contained in the first electrode active material slurry are disposed through the upper air vent. It can be easily discharged to the outside through (103A). However, in order to efficiently remove air bubbles included in the first electrode active material slurry, the upper air vent 103A is preferably installed in a direction perpendicular to the discharge direction of the first electrode active material slurry and opposite to that of gravity.
[74]
9 is a plan view illustrating an upper spacer positioned on an upper second die. For convenience of description, the position of the upper air vent 103A is indicated.
[75]
5 and 9 , the upper air vent 103A has an upper slurry receiving part ( 121) may be respectively formed on the rear side portion in the region formed in the 121). Here, "rear" means the opposite direction in which the first electrode active material is discharged. And, “side” refers to both sides in the longitudinal direction of the upper second die 101A-2 that are perpendicular to the direction in which the first active material slurry is discharged. Through this structure, there is an advantage in that the position of the upper air vent 103A facilitates maintenance and repair of the slot die coating apparatus 100 without interfering with the movement of the operator.
[76]
Referring to FIG. 7 , the lower air vent 103B passes through the upper first die 101A-1, the upper second die 101A-2, and the lower first die 101B-1 to form a lower slurry receiving part ( 111) is connected. Therefore, before the second electrode active material slurry in the lower slurry receiving part 111 flows into the lower discharge part 106 , the bubbles included in the second electrode active material slurry may be removed through the lower air vent 103B. .
[77]
The lower discharge port 106 has a structure inclined at an angle of 30 to 60 degrees with respect to the ground, and the second electrode active material slurry from the lower slurry supply port 112 is supplied to the lower slurry receiving part 111 in the opposite direction of gravity. Because of the structure, the largest number of bubbles is generated in the S region connected from the lower slurry receiving unit 111 to the lower discharge unit 106 . Therefore, it is preferable to install the lower air vent 103B in the S portion.
[78]
In addition, in consideration of the inclined structure of the lower outlet 106 , it is preferable to maintain an angle between the lower air vent 103B and the lower outlet 106 at 80 to 150 degrees.
[79]
10 is a plan view illustrating a lower spacer positioned on a lower second die. For convenience of description, the position of the lower air vent 103B is indicated. 11 is a plan view of the slot die of FIG. 4 ; For convenience of description, the boundary of the first opening 123a of the upper spacer 123 is illustrated by a dashed-dotted line, and the boundary of the second opening 113a of the lower spacer 113 is illustrated by a dotted line.
[80]
7, 10 and 11 , the lower air vent 103B is preferably installed so as not to pass through the upper discharge port 105 and the upper slurry receiving part 121 . If the lower air vent 103B passes through the portion where the upper discharge port 105 and the upper slurry receiving part 121 are formed, it may interfere with the flow of the first electrode active material slurry and bubbles may be formed in the penetrating portion. have. Accordingly, the lower air vent 103B is preferably formed through a position outside the first opening 123a of the upper spacer 123 . For example, the length W1 of the first opening 123a of the upper spacer 123 is smaller than the length W2 of the second opening 113a of the lower spacer 113, so that the lower air vent ( The 103B may be formed to pass through the through hole 123b of the upper spacer 123 .
[81]
The lower air vents 103B may be respectively formed in portions close to the side surface of the upper first die 101A-1 in the longitudinal direction of the upper first die 101A-1 perpendicular to the direction in which the second electrode active material slurry is discharged. can The position of the lower air vent 103B has the advantage of facilitating maintenance and repair of the slot die coating apparatus 100 without interfering with the movement of the operator.
[82]
In addition to the embodiment shown in FIG. 7 , the lower air vent 103B may be formed in various directions. For example, the lower air vent 103B may be formed in a rearward direction through the upper second die 101A-2 and the lower first die 101B-1 (see D of FIG. 7 ). In this case, since the lower air vent 103B does not pass through the upper spacer 123, there is an advantage that it can be installed at various positions in the lateral direction. Also, the lower air vent 103B may be formed in a lateral direction.
[83]
12 is a vertical cross-sectional view illustrating a modified example of FIG. 5 .
[84]
5 and 12 , the slot die coating apparatus 200 may have a structure in which the upper air vent 203A is bent in a “L” shape. When the bubbles included in the low-viscosity first electrode active material slurry are removed, the bubbles may be discharged together with the first electrode active material slurry. In this case, the operator can easily receive the first electrode active material slurry flowing down through the bent upper air vent 203A. Although FIG. 12 shows only a structure bent in a “L” shape, the upper air vent 203A may be bent in various shapes if it can easily receive the flowing first electrode active material slurry.
[85]
Also, the upper air vent 203A may include a valve 240 . The valve 240 is not particularly limited as long as it has a structure capable of opening and closing a hollow pipe.
[86]
Except for the structure in which the upper air vent 203A is bent in a “L” shape and includes a valve 240 , the slot die coating apparatus 200 has the same structure as the slot die coating apparatus 100 of FIG. 5 . can Accordingly, descriptions of other components will be omitted.
[87]
13 is a vertical cross-sectional view illustrating a modified example of FIG. 7 .
[88]
7 and 13 , the slot die coating apparatus 200 may have a structure in which the lower air vent 203B is bent in a “L” shape. When the bubbles included in the low-viscosity second electrode active material slurry are removed, the bubbles are discharged together with the second electrode active material slurry. At this time, the operator can easily receive the second electrode active material slurry flowing down through the bent upper air vent 203B. Although FIG. 13 shows only a structure bent in a "L" shape, the lower air vent 203B may be bent in various shapes if it can easily receive the flowing second electrode active material slurry.
[89]
Also, the upper air vent 203B may include a valve 240 . The valve 240 is not particularly limited as long as it has a structure capable of opening and closing a hollow pipe.
[90]
Except for the structure in which the upper air vent 203B is bent in a “L” shape and includes a valve 240 , the slot die coating apparatus 200 has the same structure as the slot die coating apparatus 100 of FIG. 7 . can Accordingly, descriptions of other components will be omitted.
[91]
The installation structure of the air vents 103, 203A, and 203B according to the present invention can also be applied to the slot die coating apparatus used in the single-layer active material coating process of FIG. 1 . In this case, it may be formed like the upper air vent 103A of FIG. 5 . Since the related structure has already been described above, it is omitted here.
[92]
In addition, the installation structure of the air vents 103, 203A, and 203B according to the present invention can be applied to a three-stage slot die coating apparatus in which the upper second die 101A-2 and the lower first die 101B-1 are integrally formed. can 5 , 7 , 12 , and 13 may be formed in the same structure as in FIGS. 5 , 7 , 12 , and 13 except for a structure in which the upper second die 101A - 2 and the lower first die 101B - 1 are integrally formed.
[93]
In addition, the slot die coating apparatuses 100 and 200 according to the present invention can prevent contamination of the uncoated area that occurs during intermittent coating and solve the problem of non-coating of the active material that occurs in continuous coating. In the continuous coating process, when the electrode active material slurry containing air bubbles is applied to the electrode, when the air bubbles surrounded by the slurry burst, the area where the air bubbles were located, such as a crater, is not coated with the active material. In the slot die coating apparatus 100 and 200 according to the present invention, before the electrode active material slurry is discharged to the discharge ports 105 and 106, air bubbles included in the electrode active material slurry are removed through the air vents 103, 203A, and 203B. It is possible to solve the above active material uncoated problem.
[94]
Those of ordinary skill in the art to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above content.

WE CLAIMS

A slot die coating apparatus for coating an electrode active material slurry on an electrode current collector, comprising: a coating roller; a die including a lower discharge part through which the first electrode active material slurry is discharged; and an upper die disposed on the lower die and including an upper outlet through which the second electrode active material slurry is discharged; Including, The upper die is provided with an upper air vent, the lower die is a slot die coating device with a lower air vent installed.
[Claim 2]
The slot die coating apparatus of claim 1, wherein the upper die comprises an upper first die, an upper second die and an upper spacer.
[Claim 3]
The slot die coating apparatus according to claim 2, wherein the upper discharge portion is formed by sequentially coupling the upper first die, the upper spacer, and the upper second die.
[Claim 4]
The slot die coating apparatus according to claim 3, wherein an upper slurry receiving portion is formed on the upper second die.
[Claim 5]
The slot die coating apparatus according to claim 4, wherein the upper slurry receiving part communicates with the upper discharge part.
[Claim 6]
The slot die coating apparatus of claim 3 , wherein the upper air vent passes through the upper first die and communicates with the upper slurry receiving part.
[Claim 7]
3. The slot die coating apparatus of claim 2, wherein the lower die comprises a lower first die, a lower second die and a lower spacer.
[Claim 8]
The slot die coating apparatus of claim 7 , wherein the lower discharge part is formed by sequentially coupling the lower first die, the lower spacer, and the lower second die.
[Claim 9]
The slot die coating apparatus according to claim 8, wherein a lower slurry receiving portion is formed in the lower second upper die.
[Claim 10]
The slot die coating apparatus according to claim 9, wherein the lower slurry receiving part communicates with the lower discharge part.
[Claim 11]
The slot die coating apparatus of claim 10 , wherein the lower air vent passes through the upper first die, the upper second die, and the lower first die to communicate with the lower slurry receiving part.
[Claim 12]
The slot die coating apparatus of claim 10 , wherein the lower air vent passes through the upper second die and the lower first die to communicate with the lower slurry receiving part.
[Claim 13]
The slot die coating apparatus according to claim 11, wherein the lower air vent is formed at a portion (S) where the lower slurry receiving part and the lower lead-out part are connected.
[Claim 14]
The slot die coating apparatus of claim 2 , wherein the upper spacer has a first opening and is interposed only in the remaining portion except for one side of an edge region where the upper first die and the upper second die face each other.
[Claim 15]
The slot die coating apparatus according to claim 13, wherein the lower air vent is installed through the upper spacer.
[Claim 16]
The slot die coating apparatus according to claim 1, wherein the upper air vent and/or the lower air vent have a valve.
[Claim 17]
The slot die coating apparatus according to claim 1, wherein the upper air vent and/or the lower air vent have a bent structure.