KR102666574B1 - Dual slot die coater having air vent - Google Patents

Abstract

A dual slot die coater is provided that allows the coating solution to be discharged through an outlet after removing the air bubbles contained in it. The dual slot die coater according to the present invention is a dual slot die coater that has a lower slot and an upper slot and applies a coating liquid by extruding it through at least one of the lower slot and the upper slot on the continuously running surface of the substrate. The lower die block, an intermediate die block disposed on top of the lower die block and forming the lower slot between the lower die block and the upper die block, and an intermediate die block disposed on the upper die block and forming the upper slot between the middle die block and forming an upper die block; a lower manifold that is a recessed chamber provided in the lower die block or the middle die block, accommodates a first coating liquid, and communicates with the lower slot; an upper manifold that is a recessed chamber provided in the middle die block or the upper die block, accommodates a second coating liquid, and communicates with the upper slot; a lower air vent installed in the lower manifold area; and an upper air vent installed in the upper manifold area.

Description

Dual slot die coater with air vent {DUAL SLOT DIE COATER HAVING AIR VENT}

The present invention relates to a slot die coater that forms a coating layer by discharging a coating liquid on a substrate, and more specifically, to a dual slot die coater with two slots so that two coating layers can be formed simultaneously.

As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing, and these secondary batteries essentially include an electrode assembly, which is a power generation element. The electrode assembly has a form in which a positive electrode, a separator, and a negative electrode are stacked at least once, and the positive electrode and the negative electrode are manufactured by applying and drying the positive electrode active material slurry and the negative electrode active material slurry on a current collector made of aluminum foil and copper foil, respectively. In order to uniformly charge and discharge characteristics of a secondary battery, the positive electrode active material slurry and the negative electrode active material slurry must be evenly coated on the current collector, and conventionally, a slot die coater has been used.

In the electrode manufacturing method using a slot die coater, the electrode active material slurry discharged from the slot die coater is applied onto a current collector transported by a coating roll. A conventional slot die coater includes two die blocks and a slot is formed between the two die blocks, and can form one electrode active material layer by discharging one type of electrode active material slurry through one slot.

In order to manufacture secondary batteries with high energy density, the thickness of the electrode active material layer, which was about 130㎛, gradually increases to 300㎛. After forming a thick electrode active material layer using a conventional slot die coater, migration of the binder and conductive material in the active material slurry intensifies during drying, causing the final electrode to be manufactured unevenly. To solve this problem, there is a disadvantage in that it takes a long time to coat the electrode active material layer twice, such as by applying a thin layer, drying it, and then applying it again on top of it and drying it. In order to simultaneously improve electrode performance and productivity, the inventors of the present application have proposed a dual slot die coater that can simultaneously apply two types of electrode active material slurries to the upper and lower layers.

1 is a schematic cross-sectional view of a dual slot die coater according to the prior art.

Referring to FIG. 1, while rotating the coating roll 10 to move the current collector 15, two types of electrode active material slurries are discharged from the dual slot die coater 20 to form two layers of electrodes on the current collector 15. The active material layer can be formed simultaneously. The electrode active material slurry discharged from the dual slot die coater 20 is widely spread on one side of the current collector 15 to form an electrode active material layer.

The dual slot die coater 20 is constructed by assembling three plate members, that is, three die blocks 21, 22, and 23. Since slots are formed between adjacent die blocks, two slots are formed, and two types of electrode active material slurries are simultaneously discharged through the discharge ports 24 and 25 connected to each slot, so that the electrode active material slurry is applied first. By continuously applying additional electrode active material slurry on the electrode active material layer formed by , two layers of electrode active material layers can be formed simultaneously. Reference numbers 26 and 27 are manifolds containing the electrode active material slurry.

When full-width intermittent coating is performed using the dual slot die coater 20, an uncoated area in which the electrode active material slurry is not applied is formed on the current collector 15. At this time, if bubbles exist in the electrode active material slurry, the bubbles are emitted from the discharge ports 24 and 25 and burst in the section where the uncoated area is formed. At this time, a contamination phenomenon occurs in which the electrode active material slurry surrounding the bubbles is partially applied like a spot pattern to the uncoated area. In the electrode active material coating process, the coating gap, which is the gap between the discharge ports 24 and 25 and the current collector 15, is generally formed as a narrow gap of 100 ㎛ to 200 ㎛, so the above contamination phenomenon can occur even due to fine bubbles. This happens.

Problems caused by air bubbles do not only occur in full-width intermittent coatings. When initially empty manifolds (26, 27) are supplied and filled with electrode active material slurry, the manifolds (26, 27) must be filled while the electrode active material slurry pushes out the air remaining in the empty manifolds (26, 27). If the air cannot sufficiently escape toward the discharge ports 24 and 25 and the electrode active material slurry surrounds the air in the manifold 26 and 27, it becomes bubbles in the electrode active material slurry. Since these bubbles worsen the reproducibility of the coating process and can also affect the agglomeration of the electrode active material slurry, it becomes necessary to supply the electrode active material slurry to prevent bubbles from forming or to provide a structure for already formed bubbles to escape.

As such, there is a demand for the development of a dual slot die coater with an improved structure to solve problems caused by bubbles in the electrode active material slurry.

The present invention was created in consideration of the above-mentioned problems, and is intended to provide a dual slot die coater that allows the coating liquid to be discharged through the discharge port after removing the air bubbles contained in the coating liquid.

However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

The dual slot die coater according to the present invention for solving the above technical problem is a dual slot die coater that has a lower slot and an upper slot and applies the coating liquid by extruding it through at least one of the lower slot and the upper slot on the continuously running surface of the substrate. A slot die coater, comprising: a lower die block, an intermediate die block disposed on an upper portion of the lower die block to form the lower slot between the lower die block, and an intermediate die block disposed on an upper portion of the intermediate die block and the intermediate die block; an upper die block forming the upper slot between; a lower manifold that is a recessed chamber provided in the lower die block, accommodates a first coating liquid, and communicates with the lower slot; an upper manifold that is a recessed chamber provided in the intermediate die block, accommodates a second coating liquid, and communicates with the upper slot; a lower air vent installed in the lower manifold area; and an upper air vent installed in the upper manifold area, wherein the lower die block, middle die block, and upper die block each have a lower die lip, a middle die lip, and an upper die lip forming the tip portion, A lower discharge port communicating with the lower slot is formed between the lower die lip and the middle die lip, an upper discharge port communicating with the upper slot is formed between the middle die lip and the upper die lip, and the lower air vent is It is installed so as not to penetrate the upper discharge port and the upper manifold.

The lower air vent may be provided through the upper die block and the middle die block, and the upper air vent may be provided through the upper die block.

The lower air vent or the upper air vent may be equipped with a valve.

The lower air vent or the upper air vent may have a bent structure.

The lower air vent is installed adjacent to the front end of the lower manifold without being installed in the lower land portion where the front end located on the lower discharge port side and the lower discharge port are connected among the ends of the lower manifold, and the upper air vent is installed adjacent to the front end of the lower manifold. The vent may be formed adjacent to the front end of the upper manifold without being installed in the upper land portion where the front end located near the upper discharge port and the upper discharge port are connected.

As another example, the lower air vent is installed adjacent to the front end of the lower manifold without being installed in the lower land portion where the front end located on the lower discharge port side and the lower discharge port are connected among the ends of the lower manifold, The upper air vent may be installed adjacent to a rear end of the upper manifold opposite the upper discharge port.

In a preferred embodiment, the intermediate die block has a right triangle shape in cross section along the direction in which the substrate travels, the lower manifold is provided in the lower die block, and the upper manifold is provided in the intermediate die block. do.

The lower manifold includes a first coating liquid supply port in communication with the first coating liquid supply chamber, and the upper manifold includes a second coating liquid supply port in communication with the second coating liquid supply chamber, and the first coating liquid supply port may be provided at the bottom of the lower die block, and the second coating liquid supply port may be provided at the rear of the middle die block.

The dual slot die coater includes a lower spacer interposed between the lower die block and the middle die block to adjust the width of the lower slot, and a lower spacer interposed between the middle die block and the upper die block to adjust the width of the upper slot. It may further include an upper spacer for adjustment.

At this time, the lower spacer and the upper spacer have an opening where at least one area is cut from the ends of the lower spacer and the upper spacer to determine the coating width of the coating layer applied on the substrate, and the lower air vent is connected to the upper spacer. It can be installed through the spacer.

The length of the opening of the upper spacer is smaller than the length of the opening of the lower spacer, the upper spacer includes a through hole through which the lower air vent passes, and the lower air vent passes through a location outside the opening of the upper spacer. Thus, it can penetrate the through hole.

The lower air vent may be formed backwardly through the intermediate die block.

The lower air vent may be formed in a side direction where the upper discharge port and the lower discharge port are not formed.

The lower discharge port may have a structure inclined at an angle of 30 to 60 degrees with respect to the ground.

The angle between the lower air vent and the lower discharge port may be 80 degrees to 150 degrees.

The intermediate die block includes a first intermediate die block and a second intermediate die block that are in vertical contact with each other and can be relatively moved by sliding along the contact surface, and the first intermediate die block is attached to the lower die block. The second middle die block may be fixedly coupled to the upper die block.

According to one aspect of the present invention, by using a slot die coater including an air vent, air bubbles contained in the coating liquid can be removed before the coating liquid is discharged through the discharge hole. Therefore, when used in the intermittent coating process of the electrode active material in which the electrode active material slurry is applied, it is possible to prevent the uncoated area from being contaminated with the electrode active material slurry. Since it is possible to coat electrode active material slurry with bubbles removed, the reproducibility of the coating process is excellent and the frequency of side effects such as electrode active material slurry agglomeration is reduced.

Since the air vent is located in the flow path, location selection is important. In the present invention, flow path interference due to the air vent configuration is minimized by locating the air vent in the manifold area rather than the land area. Therefore, in addition to removing air bubbles through the air vent function, the effect of minimizing width direction loading deviation can be achieved.

According to the present invention, it is possible to effectively remove bubbles contained in the coating solution and uniformly form a coating layer, especially an electrode active material layer, and because simultaneous coating of two types of electrode active material slurries is possible, both performance and productivity are excellent. Using the dual slot die coater of the present invention has the advantage of enabling uniform application even under high-speed or long-width application conditions when manufacturing secondary battery electrodes by applying electrode active material slurry on a current collector.

According to another aspect of the present invention, there is an effect of improving the fairness of dual slot coating by moving the upper die block and the lower die block relative to the coating process conditions to easily adjust the positions of the upper discharge port and lower discharge port.

The following drawings attached to this specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the invention described later, so the present invention includes the matters described in such drawings. It should not be interpreted as limited to only .
1 is a schematic cross-sectional view of a dual slot die coater according to the prior art.
Figure 2 is a schematic diagram showing a slot die coater according to an embodiment of the present invention.
FIG. 3 is a vertical cross-sectional view taken along line B-B' in FIG. 2 when viewed from direction C.
Figure 4 is a plan view showing the upper spacer of Figure 3.
FIG. 5 is a vertical cross-sectional view taken along line A-A' of FIG. 2 when viewed from direction C.
Figure 6 is a plan view showing the lower spacer of Figure 5.
Figure 7 is a top view showing the upper spacer located on the middle die block.
Figure 8 is a plan view showing the lower spacer located on the lower die block.
Figure 9 is a top view of the slot die coater of Figure 2.
Figure 10 is a vertical cross-sectional view showing a modified example of Figure 3.
Figure 11 is a vertical cross-sectional view showing a modified example of Figure 5.
Figure 12 is a schematic diagram showing a slot die coater according to another embodiment of the present invention as a modified example of Figure 2.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms or words used in this specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle of definability. Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent the entire technical idea of the present invention, so at the time of filing the present application, various options that can replace them are available. It should be understood that equivalents and variations may exist.

The dual slot die coater of the present invention is a device that has a lower slot and an upper slot and coats a coating liquid in a double layer on a substrate. The 'substrate' described below is a current collector, and the 'coating liquid' is an electrode active material slurry. The first coating liquid and the second coating liquid are both electrode active material slurries, which may mean electrode active material slurries with the same or different composition (type of active material, conductive material, binder), content (amount of active material, conductive material, binder), or physical properties. You can. The dual slot die coater of the present invention is optimized for electrode manufacturing by applying two types of electrode active material slurries simultaneously or pattern coating while alternately applying two types of electrode active material slurries. However, the scope of rights of the present invention is not necessarily limited thereto. For example, the substrate may be a porous support constituting a separator, and the first coating solution and the second coating solution may be organic materials with different compositions or physical properties. That is, if thin film coating is required, the substrate, first coating liquid, and second coating liquid may be any.

Figure 2 is a schematic diagram showing a slot die coater according to an embodiment of the present invention. FIG. 3 is a vertical cross-sectional view taken along line B-B' of FIG. 2 when viewed from direction C. Figure 4 is a plan view showing the upper spacer of Figure 3. FIG. 5 is a vertical cross-sectional view taken along line A-A' of FIG. 2 when viewed from direction C. Figure 6 is a plan view showing the lower spacer of Figure 5. Figure 7 is a plan view showing the upper spacer located on the middle die block. Figure 8 is a plan view showing the lower spacer located on the lower die block. Figure 9 is a top plan view of the slot die coater of Figure 2.

The dual slot die coater 100 according to the present invention applies the coating liquid by extruding it through at least one of the lower slot 106 and the upper slot 105 on the surface of the continuously running substrate 104. The dual slot die coater 100 has a lower slot 106 and an upper slot 105, and applies the same or different two types of coating liquids to the substrate 104 through the lower slot 106 and the upper slot 105. It is a device that can coat simultaneously or alternately.

First, referring to FIGS. 2 and 3, the dual slot die coater 100 includes a lower die block 101C, an intermediate die block 101B disposed on an upper part of the lower die block 101C, and the intermediate die block 101B. ) includes an upper die block (101A) disposed on the upper part of the die block (101A). The die blocks 10A, 101B, and 101C may be assembled together using bolts (not shown) as fastening members to form the slot die 101. In particular, the dual slot die coater 100 of the present invention is characterized by including an air vent (AIR VENT; 103).

In FIG. 3, the dual slot die coater 100 is installed so that the direction (X direction) in which the electrode active material slurry, which is a coating liquid, is discharged is substantially horizontal (approximately ±5 degrees).

The middle die block 101B is a block located in the middle among the blocks constituting the dual slot die coater 100, and is disposed between the lower die block 101C and the upper die block 101A to form a double slot. It's a block. The intermediate die block 101B of this embodiment has a right-angled cross-section along the direction in which the substrate 104 travels, but this shape is not necessarily limited to this. For example, the cross-section may be an isosceles triangle.

The side of the middle die block 101B facing the upper die block 101A is placed almost horizontally, and the opposite side of the side facing that side in the upper die block 101A (i.e., the dual slot die coater 100) The upper surface (which forms the upper surface of the outer circumference) is also placed almost horizontally. And the opposite side of the side where the lower die block 101C faces the middle die block 101B is also placed almost horizontally, and this side becomes the bottom surface (X-Z plane). The side opposite to the direction in which the electrode active material slurry is discharged, that is, the back side, of the lower die block 101C, middle die block 101B, and upper die block 101A is positioned almost vertically (Y direction).

Among the surfaces forming the outer peripheral surface of the dual slot die coater 100 in the lower die block 101C and the upper die block 101A, which are the outermost die blocks, the bottom surface of the lower die block 101C and the upper die block 101A The upper surface can be used so that it is almost perpendicular to the rear. The upper die block 101A may be divided into two regions on its upper surface. The upper surface of the upper die block 101A may include a flat portion 130 located relatively far from the upper discharge port 105a and an inclined portion 131 extending from the flat portion 130. The flat portion 130 extends in a direction parallel to the floor surface (X-Z plane), and the inclined portion 131 forms an angle of approximately 30 to 60 degrees with the flat portion 130 and may have a shape inclined diagonally downward. there is. In the middle die block (101B), the side facing the upper die block (101A) can be used so that it is almost perpendicular to the rear side.

In these die blocks (101A, 101B, 101C), the edges formed by the faces are formed at right angles, so there is a right angle in the cross section, and since the vertical or horizontal plane can be used as the reference surface, it is easy to manufacture and handle, and the precision is high. guaranteed. In addition, the combined state of the lower die block 101C, the middle die block 101B, and the upper die block 101A has an overall shape of a roughly rectangular parallelepiped, and only the front portion where the coating liquid is discharged is inclined toward the substrate 104. have it This has the advantage that the shape after assembly is roughly similar to a slot die coater having a single slot, so that a slot die coater stand, etc. can be shared.

The lower die block 101C, the middle die block 101B, and the upper die block 101A are not necessarily limited to the form shown above, for example, the direction in which the electrode active material slurry is discharged is upward and the rear face is toward the bottom. It can also be configured as a vertical die.

The die blocks 101A, 101B, and 101C are made of metal, such as SUS. Materials that are easy to process, such as SUS420J2, SUS630, SUS440C, SUS304, and SUS316L, can be used. SUS is easy to process, inexpensive, has high corrosion resistance, and has the advantage of being able to be manufactured into desired shapes at low cost.

The lower die block 101C is a block located at the bottom among the blocks constituting the dual slot die coater 100, and the side facing the middle die block 101B is approximately with respect to the horizontal plane (X-Z plane), which is the floor. It has an inclined shape to form an angle of 20 to 60 degrees.

Referring to FIG. 3, the lower slot 106 may be formed between the lower die block 101C and the middle die block 101B facing each other. For example, the lower spacer 113 is interposed between the lower die block 101C and the middle die block 101B to provide a gap between them, thereby creating a lower slot 106 corresponding to a passage through which the first coating liquid can flow. can be formed. In this case, the thickness of the lower spacer 113 determines the vertical width (Y-axis direction, slot gap) of the lower slot 106.

The lower spacer 113 has a first opening 113a with at least one area cut from the end to determine the coating width of the coating layer applied on the substrate 104 (see FIG. 6), and a lower die block ( 101C) and the middle die block 101B may be interposed in the remaining portions except for one side of the border area of each opposing surface. For example, the lower spacer 113 may have an approximately “ㄷ” planar shape. Accordingly, the lower discharge hole 106a through which the first coating liquid can be discharged to the outside is formed only between the front end of the lower die block 101C and the front end of the middle die block 101B. The front end of the lower die block 101C and the front end of the middle die block 101B are defined as the lower die lip and the middle die lip, respectively. In other words, the lower discharge port 106a is located between the lower die lip and the middle die lip. It can be said to be a place formed by separation.

For reference, the lower spacer 113 is a gasket that prevents the first coating liquid from leaking through the gap between the lower die block 101C and the middle die block 101B, except for the area where the lower discharge hole 106a is formed. It is preferable that it is made of a material that also functions as a gasket and has sealing properties.

The lower die block 101C has a lower manifold 111 having a predetermined depth on the side facing the middle die block 101B and communicating with the lower slot 106. In this embodiment, the lower manifold 111 is a recessed chamber provided in the lower die block 101C and accommodates the first coating liquid. In another embodiment, the lower manifold 111 may be provided on the intermediate die block 101B.

Although not shown in the drawing, the lower manifold 111 is connected to an externally installed first coating liquid supply chamber (not shown) through a supply pipe to continuously receive the first coating liquid. When the lower manifold 111 is filled with the first coating liquid, the first coating liquid is guided to flow along the lower slot 106 and is discharged to the outside through the lower discharge port 106a. The lower manifold 111 includes a first coating liquid supply port 112 in communication with a first coating liquid supply chamber (not shown), and the first coating liquid supply port 112 is located at the bottom of the lower die block 101C. It can be provided.

The upper die block 101A is disposed facing the upper surface of the middle die block 101B parallel to the horizontal plane. The upper slot 105 is formed between the middle die block 101B and the upper die block 101A facing each other. In the example shown in FIG. 3, the contact surface between the lower die block 101C and the middle die block 101B is inclined with respect to the horizontal plane.

Like the lower slot 106 described above, an upper spacer 123 may be interposed between the middle die block 101B and the upper die block 101A to provide a gap therebetween. As a result, an upper slot 105 corresponding to a passage through which the second coating liquid can flow is formed. In this case, the vertical width (Y-axis direction, slot gap) of the upper slot 105 is determined by the upper spacer 123.

In addition, the upper spacer 123 has a similar structure to the lower spacer 113 described above, and the upper spacer 123 has at least one area cut from the end to determine the coating width of the coating layer applied on the substrate 104. 2 It is provided with an opening portion 123a (see FIG. 4), and is included only in the remaining portion excluding one side of the border area of the opposing surfaces of the middle die block 101B and the upper die block 101A. For example, the upper spacer 123 may have an approximately “ㄷ” planar shape. Like the lower spacer 113, the circumferential direction except the front of the upper slot 105 is blocked, and the upper discharge port 105a is formed only between the tip of the middle die block 101B and the tip of the upper die block 101A. The tip of the upper die block 101A is defined as the upper die lip. In other words, the upper discharge port 105a can be said to be formed by separating the middle die lip and the upper die lip.

Referring further to FIG. 4, the upper spacer 123 is formed with a through hole 123b through which the lower air vent 103B passes. A detailed description of the lower air vent (103B) will be provided later.

As shown in FIG. 3, the middle die block 101B has an upper manifold 121 that has a predetermined depth on the surface facing the upper die block 101A and communicates with the upper slot 105. In this embodiment, the upper manifold 121 is a recessed chamber provided in the middle die block 101B and accommodates the second coating liquid. In another embodiment, the upper manifold 121 may be provided on the upper die block 101A.

Although not shown in the drawing, the upper manifold 121 is connected to an externally installed second coating liquid supply chamber and a supply pipe to continuously receive the second coating liquid. When the second coating liquid is supplied from the outside along a pipe-shaped supply pipe and fills the upper manifold 121, the second coating liquid is induced to flow along the upper slot 105 in communication with the upper manifold 121. and is discharged to the outside through the upper discharge port (105a). The upper manifold 121 includes a second coating liquid supply port 122 in communication with a second coating liquid supply chamber (not shown), and the second coating liquid supply port 122 is located on the rear of the middle die block 101B. It can be provided.

The upper slot 105 and the lower slot 106 form a certain angle, which may be approximately 30 to 70 degrees. These upper slots 105 and lower slots 106 intersect each other at one point, and the upper discharge port 105a and lower discharge port 106a may be provided near the intersection point. Accordingly, the discharge points of the first coating liquid and the second coating liquid can be concentrated at approximately one location.

According to the dual slot die coater 100 having this configuration, the rotatable coating roll 102 is placed in front of the slot die 101, and the substrate 104 to be coated is rotated by rotating the coating roll 102. ) while running, the first coating liquid and the second coating liquid are continuously brought into contact with the surface of the substrate 104 to coat the substrate 104 in a double layer. Alternatively, a pattern coating may be formed intermittently on the substrate 104 by alternately supplying and stopping the first coating solution and supplying and stopping the second coating solution.

In particular, the dual slot die coater 100 of the present invention is characterized by further including an air vent 103. 2, 3, and 5, the air vent 103 includes an upper air vent 103A and a lower air vent 103B. The upper air vent (103A) penetrates the upper die block (101A) and communicates with the upper manifold (121), and is particularly installed in the upper manifold (121) area. Accordingly, air bubbles contained in the electrode active material slurry in the upper manifold 121 can be removed through the upper air vent 103A. After the bubbles are removed, the electrode active material slurry is discharged onto the substrate 104 through the upper discharge port 105a. This upper air vent (103A) can be installed by simply drilling a hole in the upper die block (101A). Alternatively, the upper air vent (103A) can be installed by inserting a hollow pipe into the hole. The drawing shows an upper air vent (103A) using a pipe.

The upper air vent 103A provides a passage through which air in the upper manifold 121 and air in bubbles contained in the electrode active material slurry can escape to the outside. Since the upper discharge port 105a is formed in a direction parallel to the ground, no matter where the upper air vent 103A is connected to the upper manifold 121, the bubbles contained in the electrode active material slurry are not vented to the upper air vent 103A. It can be easily released to the outside through . However, in order to efficiently remove bubbles contained in the electrode active material slurry, the upper air vent 103A is preferably installed perpendicular to the direction in which the electrode active material slurry is discharged and opposite to the direction of gravity.

In particular, positioning of the upper air vent 103A is important because it is located in the flow path through which the second coating liquid flows. In the present invention, the upper air vent (103A) is installed in the upper manifold (121) area to minimize flow path interference. In other words, it is installed outside the upper manifold 121 area so as not to interfere with the flow of the second coating liquid. Installation in the upper manifold (121) area means that it is installed on the upper land portion (SA), which is the area where the front end (121a) located on the upper discharge port (105a) and the upper discharge port (105a) are connected among the ends of the upper manifold (121). It also means that it is not installed. In this embodiment, the upper air vent (103A) is installed adjacent to the rear end (121b) of the upper manifold (121), which is located opposite to the upper discharge port (105a).

Figure 7 is a plan view showing the upper spacer located on the middle die block. For convenience of explanation, the location of the upper air vent (103A) is indicated.

3 and 7, the upper air vent 103A is formed in the upper manifold 121 within the second opening 123a of the upper spacer 123 when the intermediate die block 101B is viewed from above. It may be formed in each of the posterior and lateral regions of the region. Here, “rear” means the opposite direction in which the second electrode active material slurry, which is the second coating liquid, is discharged. And, “side” refers to portions on both sides of the longitudinal direction of the middle die block 101B, which are perpendicular to the direction in which the second active material slurry is discharged. Through this structure, there is an advantage that the position of the upper air vent (103A) does not interfere with the operator's movement line and facilitates maintenance and repair of the dual slot die coater (100).

Referring to Figure 5, the lower air vent (103B) passes through the upper die block (101A) and the middle die block (101B) and communicates with the lower manifold (111). Therefore, before the first electrode active material slurry, which is the first coating liquid in the lower manifold 111, is discharged to the lower discharge port 106a, the air bubbles contained in the first electrode active material slurry must be removed through the lower air vent 103B. You can.

This lower air vent (103B) can be installed by simply drilling a hole in the upper die block (101A) and middle die block (101B). Alternatively, the lower air vent (103B) can be installed by inserting a hollow pipe into the hole. The drawing shows a lower air vent (103B) using a pipe.

The lower air vent 103B provides a passage through which air in the lower manifold 111 and air in bubbles contained in the first electrode active material slurry can escape to the outside. Since the lower air vent 103B is formed in the flow path through which the first coating liquid flows, location selection is important. In the present invention, the lower air vent (103B) is installed in the lower manifold (111) area to minimize flow path interference. In other words, it is installed outside the area of the lower manifold 111 so as not to interfere with the flow of the first coating liquid. Installation in the lower manifold 111 area means that the front end 111a located on the lower outlet 106a side of the lower manifold 111 and the lower outlet 106a are connected to the lower land portion SB. It also means that it is not installed.

The lower discharge port 106a has a structure inclined at an angle of 30 to 60 degrees with respect to the ground, and the first electrode active material slurry is supplied from the lower slurry supply port 112 to the lower manifold 111 in the opposite direction of gravity. Because of this, the most bubbles are generated in the S area connected from the lower manifold 111 to the lower discharge port 106a. Therefore, it is desirable to install the lower air vent 103B adjacent to the S area.

The S region is an area between the front end (111a) of the lower manifold (111) and the lower land portion (SB). Therefore, the lower air vent (103B) should be installed adjacent to the S area, but should not be installed in the lower land part (SB). Therefore, preferably, the lower air vent (103B) is installed adjacent to the front end (111a) of the lower manifold (111) among the ends of the lower manifold (111). Additionally, in consideration of the inclined structure of the lower outlet 106a, it is preferable that the angle formed between the lower air vent 103B and the lower outlet 106a is maintained at 80 to 150 degrees.

Figure 8 is a plan view showing the lower spacer located on the lower die block. For convenience of explanation, the location of the lower air vent (103B) is indicated. Figure 9 is a top view of the slot die of Figure 2;

Referring to FIGS. 5, 8, and 9, the lower air vent (103B) is preferably installed so as not to penetrate the upper discharge port (105a) and the upper manifold (121). If the lower air vent 103B penetrates the area where the upper discharge port 105a and the upper manifold 121 are formed, this may hinder the flow of the second electrode active material slurry and bubbles may be formed in the penetration area. . Therefore, it is preferable that the lower air vent 103B is formed through a position outside the second opening 123a of the upper spacer 123. For example, the length (W1) of the second opening (123a) of the upper spacer (123) is formed to be smaller than the length (W2) of the first opening (113a) of the lower spacer (113), so that the lower air vent (103B) ) may be formed to penetrate the through hole 123b of the upper spacer 123.

The lower air vents 103B may be formed near the side of the upper die block 101A in the longitudinal direction of the upper die block 101A perpendicular to the direction in which the first electrode active material slurry is discharged. The location of the lower air vent 103B has the advantage of facilitating maintenance and repair of the dual slot die coater 100 without interfering with the worker's movement line.

In addition to the embodiment shown in FIG. 5, the lower air vent 103B may be formed in various directions. For example, the lower air vent 103B may be formed in the rearward direction through the middle die block 101B (see D in FIG. 5).

In this case, since the lower air vent 103B does not penetrate the upper spacer 123, there is an advantage that it can be installed in various positions in the lateral direction. Additionally, the lower air vent 103B may be formed in a lateral direction.

Figure 10 is a vertical cross-sectional view showing a modified example of Figure 3.

Referring to FIGS. 3 and 10 , the dual slot die coater 200 may have a structure in which the upper air vent 203A is bent into an “L” shape. When removing bubbles contained in the low-viscosity electrode active material slurry, the bubbles may be discharged together with the electrode active material slurry. At this time, the operator can easily catch the electrode active material slurry flowing down through the bent upper air vent 203A. Although FIG. 10 shows only a structure bent in an L shape, the upper air vent 203A can be bent into various shapes as long as it can easily receive the flowing electrode active material slurry.

Additionally, the upper air vent 203A may include a valve 240. The valve 240 is not particularly limited as long as it has a structure that can open and close a hollow pipe.

Except that the upper air vent (203A) is bent in an “L” shape and includes a valve 240, the dual slot die coater 200 has the same structure as the dual slot die coater 100 of FIG. 3. You can have Accordingly, description of other components is omitted.

Figure 11 is a vertical cross-sectional view showing a modified example of Figure 5.

Referring to FIGS. 5 and 11 , the dual slot die coater 200 may have a structure in which the lower air vent 203B is bent in an “L” shape. When removing bubbles contained in the low-viscosity electrode active material slurry, the bubbles are discharged together with the electrode active material slurry. At this time, the worker can easily receive the first electrode active material slurry flowing down through the bent lower air vent 203B. Although FIG. 11 shows only a structure bent in an “L” shape, the lower air vent 203B can be bent into various shapes as long as it can easily receive the flowing electrode active material slurry.

Additionally, the upper air vent 203B may include a valve 240. The valve 240 is not particularly limited as long as it has a structure that can open and close a hollow pipe.

Except that the upper air vent (203B) is bent in an “L” shape and includes a valve 240, the dual slot die coater 200 has the same structure as the dual slot die coater 100 of FIG. 5. You can have Accordingly, description of other components is omitted.

The installation structure of the air vents 103, 203A, and 203B according to the present invention can also be applied to a single slot coater with one slot. In this case, it may be formed like the upper air vent 103A of FIG. 3. Since the related structure has already been described in detail, it is omitted here.

According to the present invention described above, the dual slot die coaters 100 and 200 including an air vent can remove air bubbles contained in the coating liquid before the coating liquid is discharged through the discharge port. Therefore, when used in the intermittent coating process of the electrode active material in which the electrode active material slurry is applied, it is possible to prevent the uncoated area from being contaminated with the electrode active material slurry. Since it is possible to coat electrode active material slurry with bubbles removed, the reproducibility of the coating process is excellent and the frequency of side effects such as electrode active material slurry agglomeration is reduced.

Since the air vent is located in the flow path, location selection is important. In the present invention, flow path interference due to the air vent configuration is minimized by locating the air vent in the manifold area rather than the land area. Therefore, in addition to removing air bubbles through the air vent function, the effect of minimizing width direction loading deviation can be achieved.

According to the present invention, it is possible to effectively remove bubbles contained in the coating solution and uniformly form a coating layer, especially an electrode active material layer, and because simultaneous coating of two types of electrode active material slurries is possible, both performance and productivity are excellent. Using the dual slot die coater of the present invention has the advantage of enabling uniform application even under high-speed or long-width application conditions when manufacturing secondary battery electrodes by applying electrode active material slurry on a current collector.

In addition, the dual slot die coater (100, 200) according to the present invention can not only prevent the non-contamination phenomenon that occurs during intermittent coating, but also solve the problem of non-coating of active material that occurs during continuous coating. In the continuous coating process, when an electrode active material slurry containing bubbles is applied to an electrode, if the bubbles surrounded by the slurry burst, an area where the bubbles were located that is not coated with the active material, like a crater, appears. In the dual slot die coater (100, 200) according to the present invention, bubbles contained in the electrode active material slurry are removed through the air vents (103, 203A, 203B) before the electrode active material slurry is discharged through the discharge ports (105a, 106a). The above problem of uncoating the active material can be solved.

Meanwhile, in this embodiment, the case where the coating liquid is applied in two layers or the coating liquid is supplied alternately for pattern coating is described as an example, but when two types of coating liquids join in the middle of the slot rather than being discharged through individual slots. However, it will be understood without further explanation that it can be applied even when applying three or more layers simultaneously by providing three or more slots.

Next, another embodiment of the present invention will be described with reference to FIG. 12. The same member numbers as those in the above-described embodiment indicate the same members, and redundant descriptions of the same members will be omitted and the description will focus on the differences from the above-described embodiment.

In the above-described embodiment, the intermediate die block 101B is composed of one block, so that the relative positions of the upper discharge port 105a and the lower discharge port 106a cannot be variably adjusted. However, according to another embodiment of the present invention, The relative positions of the upper outlet (105a) and the lower outlet (106a) can be easily adjusted.

To this end, in the dual slot die coater 100' according to another embodiment of the present invention, the intermediate die block 101B combines the first intermediate die block 101B-1 and the second intermediate die block 101B-2. Included, the first intermediate die block (101B-1) and the second intermediate die block (101B-2) are in vertical contact with each other and are provided to slide along the contact surface to enable relative movement. And the first intermediate die block (101B-1) is fixedly coupled to the lower die block (101C) by bolting, etc., and the second intermediate die block (101B-2) is fixedly coupled to the upper die block (101A) by bolting, etc. They are fixedly coupled to each other. Accordingly, the first middle die block 101B-1 and the lower die block 101C can move as one body, and the second middle die block 101B-2 and the upper die block 101A can move as one body.

The dual slot die coater 100' further includes first and second fixing parts 140 and 140' provided at the rear thereof. The first fixing part 140 fastens the lower die block 101C and the first middle die block 101B-1, and fastens the second middle die block 101B-2 and the upper die block 101A. is provided. A plurality of first fixing parts 140 may be provided along the width direction of the dual slot die coater 100'. The second fixing part 140' fastens the first intermediate die block 101B-1 and the second intermediate die block 101B-2, and fastens the lower die block 101C and the upper die block 101A. It becomes what you tell it to do. The second fixing part 140' has a certain level of assembly tolerance ( It is installed at a distance of approximately 300㎛ to 500㎛. That is, the second fixing part 140' allows the first intermediate die block 101B-1 and the second intermediate die block 101B-2 to move forward or backward, allowing them to slide and still be fixed. is fixed to prevent movement above a certain level between the first intermediate die block (101B-1) and the second intermediate die block (101B-2), but allows for slight movement due to assembly tolerances.

This dual slot die coater 100' can have two discharge ports 105a and 106a spaced apart from each other along the horizontal direction and arranged back and forth, if necessary. That is, the relative movement of the lower die block 101C and the upper die block 101A can be created by using a separate device to adjust the shape of the dual slot die coater 100' or by an operator manually.

For example, while the lower die block 101C is left motionless, the upper die block 101A is moved along the sliding surface a certain distance backward or forward, opposite to the discharge direction of the coating liquid, to form a lower discharge port ( A step may be formed between 106a) and the upper discharge port 105a. Here, the sliding surface means the opposing surface of the first intermediate die block 101B-1 and the second intermediate die block 101B-2.

The width of the step formed in this way can be determined within the range of approximately hundreds of ㎛ to several mm, which can be determined depending on the physical properties and viscosity of the first and second coating solutions formed on the substrate, or the desired thickness of each layer on the substrate. there is. For example, the thicker the coating layer to be formed on the substrate, the larger the width of the step.

In addition, as the lower discharge port 106a and the upper discharge port 105a are disposed at positions spaced apart from each other along the horizontal direction, the second coating liquid discharged from the upper discharge port 105a flows into the lower discharge port 106a. Alternatively, there is no risk of the first coating liquid discharged from the lower discharge port 106a flowing into the upper discharge port 105a.

That is, the coating liquid discharged through the lower discharge port (106a) or the upper discharge port (105a) is blocked by the surface forming the step formed between the lower discharge port (106a) and the upper discharge port (105a), so there is no risk of it flowing into the other discharge port. , This allows a more smooth multilayer active material coating process to proceed.

The dual slot die coater 100' according to another embodiment of the present invention includes the lower die block 101C and/or Alternatively, it can be simply adjusted by sliding the upper die block 101A, and there is no need to disassemble and reassemble each die block 101A, 101B, and 101C, which can greatly improve fairness.

As described above, although the present invention has been described with limited examples and drawings, the present invention is not limited thereto, and the technical idea of the present invention and the following will be understood by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalence of the claims to be described.

100, 100', 200: Dual slot die coater 101A: Upper die block
101B: intermediate die block 101B-1: first intermediate die block
101B-2: Second middle die block 101C: Lower die block
102: coating roll 103: air vent
103A, 203A: upper air vent 103B, 203B: lower air vent
104: base material 105: upper slot
105a: upper discharge port 106: lower slot
106a: lower outlet 111: lower manifold
112: first coating liquid supply port 113: lower spacer
121: upper manifold 122: second coating liquid supply port
123: upper spacer 140: first fixing part
140': second fixing part 240: valve

Claims (15)

A dual slot die coater that has a lower slot and an upper slot and applies the coating liquid by extruding it through at least one of the lower slot and the upper slot on the surface of the continuously running substrate,
a lower die block, an intermediate die block disposed on an upper portion of the lower die block and forming the lower slot between the lower die block, and an upper die block disposed on an upper portion of the intermediate die block and between the intermediate die block and the upper die block. an upper die block forming a slot;
a lower manifold that is a recessed chamber provided in the lower die block, accommodates a first coating liquid, and communicates with the lower slot;
an upper manifold that is a recessed chamber provided in the intermediate die block, accommodates a second coating liquid, and communicates with the upper slot;
a lower air vent installed in the lower manifold area; and
Including an upper air vent installed in the upper manifold area,
The lower die block, the middle die block, and the upper die block each have a lower die lip, a middle die lip, and an upper die lip forming front ends thereof, and a communication connection is made between the lower die lip and the middle die lip with the lower slot. A lower discharge port is formed, and an upper discharge port communicating with the upper slot is formed between the middle die lip and the upper die lip,
A dual slot die coater, wherein the lower air vent is installed so as not to penetrate the upper discharge port and the upper manifold. The dual slot die coater of claim 1, wherein the lower air vent is provided through the upper die block and the middle die block, and the upper air vent is provided through the upper die block. The dual slot die coater according to claim 1, wherein the lower air vent or the upper air vent is provided with a valve. The dual slot die coater according to claim 1, wherein the lower air vent or the upper air vent has a bent structure. According to paragraph 1,
The lower air vent is installed adjacent to the front end of the lower manifold without being installed in the lower land portion where the front end located on the lower discharge port side and the lower discharge port are connected among the ends of the lower manifold, and the upper air vent is installed adjacent to the front end of the lower manifold. A dual slot die, characterized in that the vent is formed adjacent to the front end of the upper manifold without being installed on the upper land portion, which is the area where the front end located on the upper discharge port side and the upper discharge port are connected among the ends of the upper manifold. cotter. According to paragraph 1,
The lower air vent is installed adjacent to the front end of the lower manifold without being installed in the lower land portion where the front end located on the lower discharge port side and the lower discharge port are connected among the ends of the lower manifold, and the upper air vent is installed adjacent to the front end of the lower manifold. A dual slot die coater, characterized in that the vent is installed adjacent to a rear end of the upper manifold located opposite the upper discharge port. The method of claim 1, wherein the intermediate die block has a right triangle shape in cross section along the direction in which the substrate travels, the lower manifold is provided in the lower die block, and the upper manifold is provided in the intermediate die block. A dual slot die coater characterized by The method of claim 7, wherein the lower manifold includes a first coating liquid supply port in communication with the first coating liquid supply chamber, and the upper manifold includes a second coating liquid supply port in communication with the second coating liquid supply chamber, The first coating liquid supply port is provided at the bottom of the lower die block, and the second coating liquid supply port is provided at the rear of the middle die block. The method of claim 1, wherein the dual slot die coater includes a lower spacer disposed between the lower die block and the middle die block to adjust the width of the lower slot, and a lower spacer disposed between the middle die block and the upper die block. A dual slot die coater, characterized in that it further comprises an upper spacer that adjusts the width of the upper slot. The method of claim 9, wherein the lower spacer and the upper spacer have an open portion where at least one area is cut from the ends of the lower spacer and the upper spacer to determine the coating width of the coating layer applied on the substrate, and the lower air vent. A dual slot die coater, characterized in that installed through the upper spacer. The method of claim 10, wherein the length of the opening of the upper spacer is smaller than the length of the opening of the lower spacer, the upper spacer includes a through hole through which the lower air vent passes, and the lower air vent is of the upper spacer. A dual slot die coater, characterized in that it penetrates the through hole through a position outside the opening. The dual slot die coater according to claim 1, wherein the lower air vent is formed in a rearward direction through the middle die block. The dual slot die coater according to claim 1, wherein the lower air vent is formed in a side direction where the upper discharge port and the lower discharge port are not formed. The dual slot die coater according to claim 1, wherein the lower discharge port is inclined at an angle of 30 to 60 degrees with respect to the ground. The dual slot die coater according to claim 1, wherein the angle formed between the lower air vent and the lower discharge port is 80 degrees to 150 degrees.