Slit die coater

Abstract

The slit die coater of the present disclosure includes a lower die block and an upper die block; a shim interposed between the lower die block and the upper die block to form a slit; and a manifold provided in the lower die block, the manifold containing a coating solution, wherein the coating solution is discharged and coated on a substrate through an outlet communicating with the slit, wherein the shim includes a plate-shaped member having an open portion cut in at least one region to determine a coating width of a coating layer coated on the substrate, and a structure protruding from the plate-shaped member and inserted into the manifold.

Description

Technical Field

[0001] This disclosure relates to a slit mold coating machine, and more specifically, to a slit mold coating machine including an improved gasket. This application claims priority to Korean Patent Application No. 10-2021-0166218, filed in Korea on November 26, 2021, and Korean Patent Application No. 10-2022-0068483, filed in Korea on June 3, 2022, the disclosure of which is incorporated herein by reference. Background Technology

[0002] With technological advancements and increasing demand for mobile devices, the need for secondary batteries as an energy source has surged. Secondary batteries essentially comprise electrode assemblies that act as power-generating elements. These electrode assemblies include a positive electrode, a separator, and a negative electrode stacked at least once. The positive and negative electrodes are manufactured by coating and drying positive and negative electrode active material slurries, respectively, onto current collectors made of aluminum foil and copper foil. Typically, for the positive electrode active material, secondary batteries utilize layered crystal structures of lithium-containing cobalt oxide (LiCoO2), lithium-containing manganese oxides such as layered crystal structures of LiMnO2 and spinel crystal structures of LiMn2O4, and lithium-containing nickel oxide (LiNiO2). Additionally, carbon-based materials are primarily used for the negative electrode active material. Recently, with the increasing demand for high-energy lithium secondary batteries, carbon-based materials can be mixed with silicon-based or silicon oxide-based materials that have an effective capacity at least 10 times greater than that of carbon-based materials. To achieve uniform charge / discharge characteristics in secondary batteries, positive and negative active material slurries must be uniformly coated on the current collector, and this is done using a slot die coating machine.

[0003] Figure 1 An example of a coating method using a conventional slot die coater is shown. Figure 2 It is taken along line II-II' Figure 1 The cross-sectional view shows the slot die coating machine along the MD direction (the direction of movement of the current collector).

[0004] Reference Figure 1 and Figure 2The electrode manufacturing method using a slit mold coating machine 30 includes coating an electrode active material slurry released from the slit mold coating machine 30 onto a current collector 20 conveyed by a coating roller 10. The electrode active material slurry released from the slit mold coating machine 30 is coated on one surface of the current collector 20 to form an electrode active material layer. The slit mold coating machine 30 includes two mold blocks 32, 34 and has a slit 36 ​​between the two mold blocks 32, 34. A manifold 38 receives electrode active material slurry supplied from a supply section (not shown) and releases the electrode active material slurry through an outlet 40 communicating with the slit 36 ​​to form an electrode active material layer. Reference numerals 42 and 44 denote mold lips at the front ends of mold blocks 32, 34, respectively, and reference numeral 46 is a landing section.

[0005] The coating width of the electrode active material layer coated on the current collector 20 is determined by the width of the slit 36. When it is necessary to change the coating width, various coating widths can be achieved by changing the shim 50, which determines the internal space of the manifold 38 and the width of the slit 36.

[0006] Figure 3 This is a diagram showing a standard gasket.

[0007] A gasket 50 is disposed on the manifold 38 in the mold block 32. The gasket 50 is a sheet-shaped member with a thickness defining the slit gap. Typically, as... Figure 3 As shown, the end of the gasket 50 is aligned with the mold lip 42. Reference numeral 60 is the injection port for supplying electrode active material slurry from the supply section, which is formed in the center of the bottom of the manifold 38 in most cases.

[0008] Figure 4 This is a diagram showing the offset of a standard gasket.

[0009] Perform shim offset O control to move the end of shim 50 backward from the mold lip 42 at the front end of mold block 32. Shim offset O control is necessary for coating width handling capability in terms of slurry release pressure, etc., but it is difficult to precisely control shim offset O and ensure reproducibility.

[0010] Figure 5 This is a diagram showing a standard pad.

[0011] As Figure 3 The deformation of the shim 50, the shim 50' controls the loading profile in the width direction by blocking the passage from the manifold 38 of the mold block 32 to the landing part 46. The shim 50' further includes a portion 52 in the central region of the shim 50. However, there are limitations to controlling the loading profile with a conventional shim 50'.

[0012] Since the shape of the manifold 38 of the mold block 32 is difficult to change once it is initially formed, it is desirable to solve problems such as shim offset control or loading profile control by improving the shim 50. Summary of the Invention

[0013] Technical issues

[0014] This disclosure is designed to address the aforementioned problems, and therefore aims to provide a slot die coating machine that includes an improved gasket.

[0015] However, the technical problems to be solved by this disclosure are not limited to those described above, and those skilled in the art will clearly understand these and other problems from the following description.

[0016] Technical solution

[0017] To address the aforementioned issues, the slit mold coating machine of this disclosure includes: a lower mold block and an upper mold block; a gasket inserted between the lower mold block and the upper mold block to form a slit; and a manifold disposed in the lower mold block, the manifold containing a coating solution, wherein the coating solution is released through an outlet communicating with the slit and coated onto a substrate, wherein the gasket includes a plate-shaped member and a structure protruding from the plate-shaped member and inserted into the manifold, the plate-shaped member having an opening portion cut in at least one region to determine the coating width of the coating layer coated on the substrate.

[0018] The structure can be integrally formed with the plate-shaped member.

[0019] Behind and in front of the manifold, the lower surface of the upper mold block and the upper surface of the gasket can be joined together without gaps, and the upper surface of the lower mold block and the lower surface of the gasket can be joined together without gaps.

[0020] The upper surface of the gasket may be flat, and the structure may protrude from a portion of the lower surface of the gasket.

[0021] The plate-shaped member may include a first portion serving as a base and at least two second portions extending from the first portion, and the second portions may be connected to the same side of the first portion and extend in the same direction.

[0022] The structure can be a side structure, which is inserted into the two ends of the manifold at the two ends of the plate-shaped member in the area where the manifold contacts the two ends, thereby ensuring the position reproducibility of the gasket.

[0023] The side structure may have the same shape as the cross-sectional shape of the manifold for fitting into the manifold, including the bottom of the manifold.

[0024] In one example, the plate-shaped member may include a first portion serving as a base and at least two second portions extending from the first portion, the second portions being connected to the same side of the first portion and extending in the same direction, and the side structure extending downward and protruding from the inner sidewall of the second portion near the manifold.

[0025] The structure may be an extended partition structure that extends from the center of the plate-shaped member toward the outlet, and the partition structure is thicker than the plate-shaped member and has a thickness that allows it to be inserted into the manifold.

[0026] Specifically, the plate-shaped member may include a first portion serving as a base and at least two second portions extending from the first portion, the second portions being connected to the same side of the first portion and extending in the same direction, and the partition structure extending from the center of the first portion in the same direction as the second portions and extending downward and protruding.

[0027] The structure may be a branched structure in which the coating solution coming out of the injection port at the bottom of the manifold is divided into two branches.

[0028] The branch structure may include an extension portion extending downward along the sidewall of the manifold, and a base portion connected to the extension portion and placed along the bottom of the manifold.

[0029] The branch structure may further include a plurality of gasket injection ports in the bottom portion.

[0030] The plurality of gasket injection ports may have a diameter that increases from the center to one side.

[0031] In another example, the plate-shaped member may include a first portion serving as a base and at least two second portions extending from the first portion, the second portions being connected to the same side of the first portion and extending in the same direction, the extension portions extending downward from the first portion and protruding, and the bottom portion being integrally connected to the lower end of the extension portions.

[0032] In this case, the slot die coating machine may further include a plurality of gasket injection ports in the bottom portion, the plurality of gasket injection ports having a diameter that increases from the center to one side, and the plurality of gasket injection ports may be circular in shape.

[0033] Beneficial effects

[0034] According to one aspect of this disclosure, gasket offset reproducibility can be ensured when the gasket is assembled into a slot die coating machine.

[0035] According to another aspect of this disclosure, the loading profile in the width direction can be easily controlled.

[0036] Once the shape of the manifold is initially formed, it is difficult to change. According to another aspect of this disclosure, the manifold area of ​​the slot die coater can be reconstructed by the shape of the gasket without changing the manifold.

[0037] Thus, according to this disclosure, a coating solution flow path structure that is impossible for conventional gaskets for sheet-shaped components can be formed, and the coating width and loading capacity can be improved.

[0038] This disclosure provides a slot die coating machine including a gasket that incorporates novel functional structures above and below a plate-shaped member, rather than a simple sheet member. Preferably, the novel functional structures are included below the plate-shaped member to utilize a manifold structure beneath the gasket.

[0039] Since the corresponding functional structure mainly involves the manifold, the position reproducibility of the gasket itself can be ensured, or the flow path structure in the manifold can be reconstructed to form a flow path structure that is impossible for conventional sheet components, and the quality of coating width and loading capacity can be improved.

[0040] The electrode active material layer can be stably formed using a slot die coating machine according to this disclosure. Attached Figure Description

[0041] The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the following detailed description, are intended to provide a further understanding of the technical aspects of the present disclosure; therefore, the present disclosure is not to be construed as being limited to these drawings.

[0042] Figure 1 An example of a coating method using a conventional slot die coater is shown.

[0043] Figure 2 It is taken along line II-II' Figure 1 The cross-sectional view shows the slot die coating machine along the MD direction (the direction of movement of the current collector).

[0044] Figure 3 This is a diagram showing a standard gasket.

[0045] Figure 4 This is a diagram showing the offset of a standard gasket.

[0046] Figure 5 This is a diagram showing a standard pad.

[0047] Figure 6 This is a cross-sectional view of a slot die coating machine according to an embodiment of the present disclosure.

[0048] Figure 7 This is a bottom perspective view showing an example of a gasket that may be included in a slot die coating machine as described in this disclosure.

[0049] Figure 8 yes Figure 7 A perspective view of the gasket and the lower mold block.

[0050] Figure 9 It was assembled Figure 7 Side view of the lower mold block of the gasket.

[0051] Figure 10 This is a bottom perspective view showing another example of a gasket that may be included in a slot die coating machine as described in this disclosure.

[0052] Figure 11 yes Figure 10 A perspective view of the gasket and the lower mold block.

[0053] Figure 12 This is a bottom perspective view showing another example of a gasket that may be included in a slot die coating machine as described in this disclosure.

[0054] Figure 13 yes Figure 12 A perspective view of the gasket and the lower mold block.

[0055] Figure 14 This is a perspective view of another example of a gasket and lower die block that may be included in the slot die coating machine described in this disclosure. Detailed Implementation

[0056] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms or words used in the specification and appended claims should not be construed as limited to their general or dictionary meanings, but rather interpreted based on their meanings and concepts corresponding to the technical aspects of the present disclosure, on the basis of allowing the inventors to appropriately define the terms used for best interpretation. Therefore, the embodiments described herein and the descriptions in the accompanying drawings are merely exemplary embodiments of the present disclosure and do not fully describe the technical aspects of the present disclosure; thus, it should be understood that various other equivalents and modifications may be made thereto upon filing this application.

[0057] The same reference numerals denote the same elements. Furthermore, in the accompanying drawings, to effectively depict the technical subject matter, the elements are shown with enlarged thickness, scale, and dimensions.

[0058] The slit-die coating machine disclosed herein is an apparatus having a slit for applying a coating solution onto a substrate through the slit. In the following description, "substrate" refers to a current collector, and "coating solution" refers to an electrode active material slurry. However, the scope of protection of this disclosure is not necessarily limited thereto. For example, the substrate may be a porous support for a diaphragm, and the coating solution may be an organic substance. That is, any type of substrate and coating solution can be used when thin film coating is required. In this disclosure, "front" refers to the outlet side, and "rear" refers to the opposite side.

[0059] This disclosure aims to ensure the reproducibility of shim offset in slot die coaters. This disclosure reconstructs the manifold region of the slot die coater by changing the shape of the shim, thereby creating a flow path structure impossible for conventional shims on sheet-shaped components, and improving coating width and load handling capacity.

[0060] This disclosure proposes incorporating gaskets with novel functional structures above and below the plate-shaped member, instead of a simple sheet member. Preferably, the novel functional structures are included below the plate-shaped member to utilize a manifold structure beneath the gaskets.

[0061] Since the corresponding functional structure mainly involves the manifold, the position reproducibility of the gasket itself can be ensured, or the flow path structure in the manifold can be reconstructed, thereby forming a flow path structure that is impossible for conventional gaskets of sheet components, and improving the quality of coating width and loading capacity.

[0062] Figure 6 This is a cross-sectional view of a slot die coating machine according to an embodiment of the present disclosure.

[0063] The slit mold coating machine 100 of this disclosure includes a lower mold block 110 and an upper mold block 120. A gasket 130 is located between the lower mold block 110 and the upper mold block 120 to form a slit 101.

[0064] The lower mold block 110 includes a manifold 115. The manifold 115 contains a coating solution 150. The slot die coater 100 releases the coating solution 150 through an outlet 110a communicating with the slot 101 and coats it onto the substrate 190.

[0065] In addition to the lower die block 110 and the upper die block 120, the slit die coating machine 100 may further include another die block. A spacer 130 may be included between every two die blocks to form two or more slits. The lower die block 110 and the upper die block 120 are named based on the spacer 130, and in the case of more die blocks, the lower die block 110 or the upper die block 120 may become an intermediate die block.

[0066] In addition, Figure 6In this embodiment, the slit mold coating machine 100 is mounted such that the release direction (X direction) of the coating solution or electrode active material slurry is almost horizontal (approximately ±5°). However, this disclosure is not limited thereto; for example, the slit mold coating machine 100 may be a vertical mold type, such that the release direction of the electrode active material slurry is upward (Y direction).

[0067] A slit 101 is formed in the region where two mold blocks 110 and 120 face each other. Here, a gasket 130 is positioned between the mold blocks 110 and 120 to form a gap that becomes the slit 101, which corresponds to the flow path of the coating solution 150. The thickness of the gasket 130 determines the vertical width (Y direction, slit gap) of the slit 101.

[0068] The gasket 130 is characterized by including a plate-shaped member and a structure protruding from the plate-shaped member and inserted into the manifold 115, the plate-shaped member having an opening portion cut in at least one region to determine the coating width of a coating layer applied to the substrate 190, the structure being integrally formed with the plate-shaped member. This structure will be described in more detail below.

[0069] The gasket 130 has an opening cut out in one region, and the gasket 130 may be located in the remaining region except one side of the edge of each opposing surface of the mold blocks 110, 120. Therefore, an outlet 110a for the coating solution 150 to exit is present between the mold lips 111, 131 located at the front ends of the mold blocks 110, 120, respectively. The outlet 110a may be formed by the gap between the mold lips 111, 131.

[0070] For reference, gasket 130 serves as a liner to prevent the coating solution 150 from leaking through the gap between the two mold blocks 110, 120, except in the area where the outlet 110a is located, and gasket 130 is preferably made of a sealing material.

[0071] Either of the two mold blocks 110, 120 includes a manifold 115 of predetermined depth, which communicates with the slit 101. In this embodiment, the manifold 115 is included in the lower mold block 110 as an example. Although not shown, the manifold 115 is connected via a supply pipe to an externally mounted coating solution supply chamber (not shown) and is supplied with coating solution 150. When the manifold 115 is filled with coating solution 150, the flow of coating solution 150 is guided along the slit 101 and exits the outlet 110a.

[0072] Behind the manifold 115, the lower surface of the upper mold block 120 and the upper surface of the gasket 130 can be joined together without gaps, and the upper surface of the lower mold block 110 and the lower surface of the gasket 130 can be joined together without gaps. Furthermore, in front of the manifold 115, the lower surface of the upper mold block 120 and the upper surface of the gasket 130 can be joined together without gaps, and the upper surface of the lower mold block 110 and the lower surface of the gasket 130 can be joined together without gaps. Thus, the coating solution 150 flows only within the slit 101 defined by the gasket 130.

[0073] According to the slit mold coating machine 100 having this configuration, while the substrate 190 to be coated moves by the rotation of the rotatable coating roller 180 disposed on the front side of the slit mold coating machine 100, the coating solution 150 can be released and continuously coated in contact with the surface of the substrate 190. Alternatively, pattern coating can be intermittently formed on the substrate 190 by alternately providing and stopping the supply of the coating solution 150.

[0074] Here, the spacer 130 defines the coating width of the coating layer applied to the substrate 190, and according to this disclosure, the spacer 130 is characterized by including a plate-shaped member and the structure described herein. Embodiments of the structure may include reference to... Figures 7 to 14 Those described. Figures 7 to 14 This is a diagram illustrating a gasket according to various embodiments that may be included in a slot die coating machine as described in this disclosure. The structure is intended to achieve the functional structure described above and may be... Figure 7 , Figure 10 and Figure 12 The three types shown can be used individually or in various combinations. For example, Figure 14 The combination of three structures is shown.

[0075] Conventional gaskets are sheet-shaped components and correspond to a 2D planar structure, while this disclosure further includes, above and / or below, a structure preferably extending into the manifold, serving as the base of the gasket, thus possessing a 3D three-dimensional structure. In particular, this 3D three-dimensional structure differs from the 2D planar structure that is maintained during the application of deformation forces to various portions of the gasket, but reverts to the 2D planar structure when the deformation forces are removed. This 3D three-dimensional structure is formed by the shape of the gasket itself, and there is no deformation of the gasket before and after it is incorporated into the slot die coating machine.

[0076] The gasket 130 may be made of plastic or metal, but this disclosure is not limited thereto. For example, the gasket 130 may be a resin sheet of Teflon, polyester, etc., or a metal sheet of copper, aluminum, etc. The gasket 130 may be connected and fixed to at least one of the two mold blocks 110, 120 by screws, for example, but this disclosure is not limited thereto.

[0077] first, Figure 7 This is a bottom perspective view showing an example of a gasket that may be included in a slot die coating machine as described in this disclosure. Figure 8 yes Figure 7 A perspective view of the gasket and the lower mold block. Figure 9 It was assembled Figure 7 Side view of the lower mold block of the gasket.

[0078] Reference Figures 7 to 9 The gasket 130 includes a plate-shaped member 132 and a side structure 134 protruding from the plate-shaped member 132 and inserted into the manifold 115. The plate-shaped member 132 includes an opening 130a cut in at least one region to determine the coating width of a coating layer applied to the substrate 190. The upper surface of the gasket 130 or the surface in contact with the upper mold block 120 may be flat, and the side structure 134 may protrude from a portion of the lower surface of the gasket 130 or the surface in contact with the lower mold block 110.

[0079] Side structure 134 ensures the positional reproducibility of the gasket 130 itself. Reference numeral 117 is the injection port at the bottom center of the manifold 115, from which electrode active material slurry is supplied from the supply section.

[0080] Side structure 134 can be inserted into both ends of manifold 115 in the areas where it contacts both ends of plate member 132, thereby ensuring the positional reproducibility of gasket 130. Side structure 134 can protrude from plate member 132 and be inserted into both ends of manifold 115 in the areas where it contacts both ends of plate member 132.

[0081] The plate-shaped member 132 may include a first portion 132a serving as a base and at least two second portions 132b extending from the first portion 132a. The first portion 132a is the portion of the gasket 130 placed on the rear side of the lower mold block 110. For the gasket 130 disposed in the remaining area except one side of the edge of each opposing surface of the upper mold block 120 and the lower mold block 110, the number of second portions 132b is at least two. In this embodiment, two second portions 132b are shown by way of example. An opening 130a is located between two adjacent second portions 132b. As the number of second portions 132b increases, two or more coating layers may be formed side by side on the substrate 190. That is, a striped pattern coating may be formed. This disclosure is not limited to the number of second portions 132b.

[0082] The second portion 132b is connected to the same side of the first portion 132a and extends in the same direction. The second portion 132b is the portion of the gasket 130 that extends to the front side of the lower mold block 110. The side structure 134 extends downward and protrudes from the inner sidewall of the second portion 132b near the manifold 115. The second portion 132b and the side structure 134 can be integrally formed. That is, there is no gap or interval between the second portion 132b and the side structure 134. Therefore, unnecessary flow of coating solution between the side structure 134 and the second portion 132b can be prevented.

[0083] For example, plate member 132 is A plate-shaped component, and may have the same shape as... Figure 3 The gasket 130 of this disclosure has a similar shape to the conventional gaskets described herein. The gasket 130 includes a plate-shaped member 132 and further includes side structures 134 that project downwards from the plate-shaped member 132 and are inserted into the manifold 115 below the gasket 130 at a location close to the two sidewalls of the manifold 115 (located on both sides in the width direction of the slot die coater). The side structures 134 inserted into the manifold 115 improve the assembly accuracy of the gasket 130. Furthermore, when the end of the gasket 130 is designed to offset from the die lip 111, the gasket 130 is always placed in the same position, thus maintaining the originally designed offset. Therefore, gasket offset reproducibility is ensured when the gasket 130 is assembled into the slot die coater 100.

[0084] The side structure 134 may have the same cross-sectional shape as the manifold 115 to fit into the manifold 115, including its bottom, thereby securing its position and preventing unnecessary flow of the coating solution near the side structure 134. In one example, if the cross-section of the manifold 115 is semi-circular, the side structure 134 may have a matching semi-circular shape. In another example, if the cross-section of the manifold 115 is trapezoidal, the side structure 134 may have a matching trapezoidal shape.

[0085] The plate-shaped member 132 and the side structure 134 can be integrally formed. That is, the side structure 134 is not formed by adding or attaching another member to the plate-shaped member 132, but can be integrally formed during the manufacture of the gasket 130. The plate-shaped member 132 and the side structure 134 are seamlessly connected. Therefore, the manufacturing process is more straightforward, eliminating the need to consider and manage the bond strength between the plate-shaped member 132 and the side structure 134, which would be necessary if they were separate structures, and the structure is robust. Furthermore, it prevents grout from unnecessarily remaining between the plate-shaped member 132 and the side structure 134.

[0086] Figure 10This is a bottom perspective view showing another example of a gasket that may be included in a slot die coating machine as described in this disclosure. Figure 11 yes Figure 10 A perspective view of the gasket and the lower mold block.

[0087] In Figure 10 and Figure 11 The structure described is a partition structure extending below the plate-shaped member.

[0088] Reference Figure 10 and Figure 11 The gasket 130 includes a plate-shaped member 132 and a partition structure 136 protruding from the plate-shaped member 132 and inserted into a manifold 115. The plate-shaped member 132 has an opening 130a cut in at least one region to determine the width of a coating layer applied to a substrate 190. The partition structure 136 extends from the center of the plate-shaped member 132 toward an outlet 110a and has a thickness sufficient for insertion into the manifold 115. In particular, the partition structure 136 is thicker than the plate-shaped member 132. (See reference...) Figure 5 Compared to the shape of the conventional pad 50' described, the partition structure 136 extends into the manifold 115 with a predetermined thickness, and thus the partition structure 136 can be referred to as a reinforcing pad.

[0089] With reference Figure 7 In the same manner as described, the plate-shaped member 132 includes a first portion 132a serving as a base and a second portion 132b extending from the first portion 132a. A partition structure 136 extends downward and protrudes from the center of the first portion 132a in the same direction as the second portion 132b. The first portion 132a and the partition structure 136 may be integrally formed. That is, there is no gap or interval between the first portion 132a and the partition structure 136. Therefore, unnecessary flow of the coating solution between the partition structure 136 and the first portion 132a can be prevented.

[0090] In a conventional pad 50', the pad 50 and the sheet portion 52 have the same thickness. That is, the upper or lower surface of the pad 50' is flat. The pad 50' is only used to control the loading amount by changing the flow of the slurry. In contrast, the partition structure 136 of the pad 130 of this disclosure may be thicker than the sheet member 132 and may protrude from the sheet member 132, thus having a greater mass. Therefore, the partition structure 136 has higher strength and includes a step that is engaged in the step of the manifold 115, thus preventing deformation or damage and fixing the position when the partition structure 136 is placed under force in any direction. As described above, the partition structure 136 has higher structural strength.

[0091] The partition structure 136 provides flow rate regulation to the gasket 130. The partition structure 136 can protrude as far as possible towards the outlet 110a in the center, as shown. Based on the center of the partition structure 136, the central flow channel can be narrower than the flow channels on both sides. Therefore, as the coating solution 150 passes through the gasket 130, the pressure in the center increases, and the coating solution 150 moves along the partition structure 136 to both sides. The partition structure 136 can have a sloped polygonal structure as shown, can have a gradually rounded shape, and its shape can be adjusted according to the characteristics of the coating solution and process conditions. With the gasket 130 including the partition structure 136, the loading profile in the width direction can be easily controlled.

[0092] The plate-shaped member 132 and the partition structure 136 can be integrally formed. That is, the partition structure 136 is not formed by adding or attaching another member to the plate-shaped member 132, but can be integrally formed during the manufacture of the gasket 130. The plate-shaped member 132 and the partition structure 136 are seamlessly connected. Therefore, the manufacturing process is more straightforward, eliminating the need to consider and manage the bond strength between the plate-shaped member 132 and the partition structure 136 if they were separate structures, and the structure is robust. Furthermore, it prevents slurry from unnecessarily remaining between the plate-shaped member 132 and the partition structure 136.

[0093] Figure 12 This is a bottom perspective view showing another example of a gasket that may be included in a slot die coating machine as described in this disclosure. Figure 13 yes Figure 12 A perspective view of the gasket and lower mold block. (Will be displayed) Figure 12 and Figure 13 The description in the text corresponds to the entire flow path of the reconstructed manifold.

[0094] Reference Figure 12 and Figure 13 The gasket 130 includes a plate-shaped member 132 and a branch structure 138 protruding from the plate-shaped member 132 and inserted into the manifold 115. The plate-shaped member 132 has an opening 130a cut in at least one region to determine the coating width of the coating layer applied to the substrate 190. The branch structure 138 divides the coating solution exiting from the inlet 117 formed at the bottom of the manifold 115 into two streams.

[0095] like Figures 3 to 5As shown, in a conventional manifold 38, the inlet 60 is located at the bottom center. Due to the location of the inlet 60, in conventional techniques, the load at the center is often higher. In this disclosure, to address this issue, a branch structure 138 extends into the manifold 115 and splits the coating solution exiting the inlet 117 into two branches. This is controlled by guiding the movement of the coating solution along the branch structure 138, thereby preventing increased load on either side.

[0096] The branch structure 138 includes an extension 138a extending downward along the sidewall of the manifold 115, and a bottom portion 138b connected to the extension 138a and positioned along the bottom of the manifold 115. The bottom portion 138b includes a plurality of gasket inlets 139a, 139b, 139c, and 139d with increasing diameters from the center to one side.

[0097] With reference Figure 7 In the same manner as described, the plate-shaped member 132 includes a first portion 132a serving as a base and a second portion 132b extending from the first portion 132a. An extension portion 138a may extend downward from and protrude from the first portion 132a, and a bottom portion 138b may be integrally connected to the lower end of the extension portion 138a. The gasket inlets 139a, 139b, 139c, and 139d may be, for example, circular in shape.

[0098] The first portion 132a and the extension portion 138a can be integrally formed. That is, there is no gap or interval between the first portion 132a and the extension portion 138a. Therefore, unnecessary flow of the coating solution between the extension portion 138a and the first portion 132a can be prevented.

[0099] By guiding the movement of the coating solution from the existing inlet 117 to the new gasket inlets 139a, 139b, 139c, and 139d, flow concentration near the center of inlet 117 is prevented. The flow path can be reconstructed by simply adjusting the gasket 130 without altering the structure of manifold 115, and the position of the gasket 130 is more securely fixed due to the branch structure 138 inserted into manifold 115.

[0100] The shape of manifold 115 is difficult to change once it is initially formed. According to this disclosure, the manifold 115 region of the slot die coater 100 can be reconstructed by a gasket 130 including branch structure 138 without changing the manifold 115.

[0101] Figure 14 The gasket 130 is shown, comprising all three structures 134, 136, and 138 described above. If needed, it can be... Figure 7 The side structure 134 and Figure 12The branch structure 138 combination, or the Figure 7 The side structure 134 and Figure 10 The 136-combination of the partition structure, or the combination of... Figure 10 The partition structure 136 and Figure 12 The branch structure 138 is combined to form the gasket 130.

[0102] A slit mold coating machine 100 and its deformation can be used to stably form an electrode active material layer. For example, the slit mold coating machine 100 can be used to coat a positive electrode active material slurry to manufacture the positive electrode of a secondary battery.

[0103] The positive electrode includes a current collector and a layer of positive electrode active material on the surface of the current collector. The current collector may include a conductive material, such as Al or Cu, and a suitable one may be used according to the polarity of the current collector electrode known in the field of secondary batteries. The positive electrode active material layer may further include at least one of a plurality of positive electrode active material particles, a conductive material, or a binder. In addition, the positive electrode may further include various additives to further enhance electrical and chemical properties.

[0104] The active material is not limited to a specific type and may include any type of active material capable of being used as a positive electrode active material in lithium-ion secondary batteries. Non-limiting examples may include at least one of the following: layered compounds or compounds substituted with one or more transition metals, such as lithium manganese composite oxides (LiMn2O4, LiMNO2), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2); compounds of the chemical formula Li 1+x Mn 2-x Lithium manganese oxides represented by O4 (x is 0 to 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides, such as LiV3O8, LiV3O4, V2O5, Cu2V2O7; and those represented by the chemical formula LiNi 1-x M x Lithium nickel oxides with Ni sites represented by O2 (M = Co, Mn, Al, Cu, Fe, Mg, B, or Ga, x = 0.01 to 0.3); LiMn 2-x M x Lithium manganese composite oxides represented by O2 (M = Co, Ni, Fe, Cr, Zn, or Ta, x = 0.01 to 0.1) or the chemical formula Li2Mn3MO8 (M = Fe, Co, Ni, Cu, or Zn); LiMn2O4 having Li in the chemical formula partially replaced by alkaline earth metal ions; disulfide compounds; or Fe2(MoO4)3. In this disclosure, the positive electrode may include a solid electrolyte material, such as at least one of a polymer-based solid electrolyte, an oxide-based solid electrolyte, or a sulfide-based solid electrolyte.

[0105] Conductive materials are typically added in amounts ranging from 1 wt% to 20 wt% based on the total weight of the mixture including the active materials. Conductive materials are not limited to a specific type and may include any material that has conductive properties without causing any chemical change to the corresponding battery, for example, selected from at least one of the following: graphite, such as natural graphite and artificial graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers, such as carbon fibers and metal fibers; metal powders, such as fluorinated carbon powder, aluminum powder, and nickel powder; conductive whiskers, such as zinc oxide and potassium titanate; conductive metal oxides, such as titanium oxide; and conductive materials, such as polyphenylene derivatives.

[0106] The adhesive is not limited to a specific type and may include any material that helps bond the active and conductive materials together and to the current collector, such as polyvinylidene fluoride, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, and various copolymers thereof. The adhesive is typically included in the range of 1 wt% to 30 wt% or 1 wt% to 10 wt% based on 100 wt% of the electrode layer.

[0107] The slit mold coating machine 100 of this disclosure can be used to coat a negative electrode active material slurry to manufacture the negative electrode of a secondary battery. The negative electrode includes a current collector and a layer of negative electrode active material on the surface of the current collector. The negative electrode active material layer may further include at least one of a plurality of negative electrode active material particles, a conductive material, or a binder. In addition, the negative electrode may further include various additives to further enhance electrical and chemical properties.

[0108] Negative electrode active materials may include: carbon materials, such as graphite, amorphous carbon, diamond-like carbon, fullerenes, carbon nanotubes, and carbon nanohorns; lithium metal materials; alloy materials, such as silicon or tin alloys; and oxide materials, such as Nb₂O₅ and Li₅Ti₄O₂. 12 TiO2; or their complexes. For details on the conductive materials, binders, and current collectors of the negative electrode, please refer to the description of the positive electrode.

[0109] Active material slurries, including positive or negative electrode active materials, have very high viscosity. For example, the viscosity can be 1000 cps or greater. Active material slurries used to form electrodes in secondary batteries can have a viscosity of 2000 cps to 30000 cps. For example, the viscosity of negative electrode active material slurries can be 2000 cps to 4000 cps. The viscosity of positive electrode active material slurries can be 8000 cps to 30000 cps. Because coating solutions with viscosities of 1000 cps or greater are required, the slot die coating machine 100 of this disclosure is structurally different from devices used for coating any other coating solutions with lower viscosities, such as common resin solutions like photosensitive emulsions, magnetic solutions, anti-reflective or anti-glare solutions, solutions for increasing viewing angles, and pigment solutions for color filters, and cannot be achieved through design modifications. Because the slit mold coating machine 100 of this disclosure is designed, for example, to coat an active material slurry comprising an active material having an average particle size of approximately 10 μm, its structure differs from that of any other coating solution used for coating particles that do not contain particles having the aforementioned particle size, and cannot be achieved through design modifications. The slit mold coating machine 100 of this disclosure is the optimal coating machine for electrode manufacturing.

[0110] Although the present disclosure has been described above with respect to a limited number of embodiments and accompanying drawings, the present disclosure is not limited thereto, and it will be apparent to those skilled in the art that various changes and modifications may be made to the technical aspects of the present disclosure and to the appended claims and their equivalents.

[0111] [Description of reference markers]

[0112] 100: Slit mold coating machine; 110: Lower mold block

[0113] 115: Manifold 117: Inlet

[0114] 120: Upper mold block; 130: Gasket

[0115] 132: Plate-shaped component; 134: Side structure

[0116] 136: Separated structure; 138: Branched structure

[0117] 138a: Extension portion; 138b: Bottom portion

[0118] 139a, 139b, 139c, 139d: Gasket injection ports

[0119] 150: Coating solution; 180: Coating roller

[0120] 190: Substrate.

Claims

1. A slit die coater comprising: a lower die block and an upper die block; a shim interposed between the lower die block and the upper die block to form a slit; and a manifold provided in the lower die block, the manifold accommodating a coating solution, wherein the coating solution is discharged and coated on a substrate through an outlet communicating with the slit, wherein the shim includes a plate-shaped member having an open portion cut in at least one region to determine a coating width of a coating layer coated on the substrate, and a structure protruding from the plate-shaped member and inserted into the manifold, and wherein the structure is a branch structure that divides the coating solution coming out of an injection port of a bottom of the manifold into two branches.

2. The slit die coater according to claim 1, wherein the structure is integrally formed with the plate-shaped member.

3. The slit die coater according to claim 1, wherein a lower surface of the upper die block and an upper surface of the shim are combined with each other without a gap at a rear of the manifold and at a front of the manifold, and an upper surface of the lower die block and a lower surface of the shim are combined with each other without a gap.

4. The slit die coater according to claim 1, wherein the upper surface of the shim is flat, and the structure protrudes from a portion of the lower surface of the shim.

5. The slit die coater according to claim 1, wherein the plate-shaped member includes a first portion serving as a base and at least two second portions extending from the first portion, and the second portions are connected to the same side of the first portion and extend in the same direction.

6. The slit die coater according to claim 1, wherein the shim further includes a structure that is a side structure inserted into both ends of the manifold at regions where both ends of the plate-shaped member are in contact with the manifold, thereby ensuring position reproducibility of the shim.

7. The slit die coater according to claim 6, wherein the side structure has the same shape as a sectional shape of the manifold to be closely fitted into the manifold including the bottom of the manifold.

8. The slit die coater according to claim 6, wherein the plate-shaped member includes a first portion serving as a base and at least two second portions extending from the first portion, the second portions are connected to the same side of the first portion and extend in the same direction, and the side structure extends downward from an inner side wall close to the second portion of the manifold and protrudes.

9. The slit die coater according to claim 1, wherein the shim further includes a structure that is an extended partition structure extending from a center of the plate-shaped member toward the outlet, and the partition structure is thicker than the plate-shaped member to have a thickness inserted into the manifold. ​ 10.The slit die coater of claim 9, wherein the plate-shaped member includes a first portion serving as a base and at least two second portions extending from the first portion, the second portions being connected to the same side of the first portion and extending in the same direction, and the partition structure extends from the center of the first portion in the same direction as the second portions and extends downward and protrudes. 11.The slit die coater of claim 1, wherein the branch structure includes an extension portion extending downward along the sidewall of the manifold, and a bottom portion connected to the extension portion and placed along the bottom of the manifold. 12.The slit die coater of claim 11, further comprising: a plurality of shim injection ports in the bottom portion. 13.The slit die coater of claim 12, wherein the plurality of shim injection ports have diameters that increase from the center to one side. 14.The slit die coater of claim 11, wherein the plate-shaped member includes a first portion serving as a base and at least two second portions extending from the first portion, the second portions being connected to the same side of the first portion and extending in the same direction, the extension portion extending downward and protruding from the first portion, and the bottom portion being integrally connected to the lower end of the extension portion. 15.The slit die coater of claim 14, further comprising: a plurality of shim injection ports in the bottom portion, the plurality of shim injection ports having diameters that increase from the center to one side, wherein the plurality of shim injection ports are circular in shape.

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