Slit die coater

Abstract

This invention aims to achieve uniform coating width in multi-channel molds and reduce state adjustment losses during subsequent production. The slit mold coating machine of this invention includes: an upper plate; a lower plate; and a gasket positioned between the upper and lower plates, defining at least two separate channels to form a slit; wherein the gasket defining the separate channels includes a fixing pin for improving positioning accuracy when fixed to the upper or lower plate and a fixing bolt for fixing to the upper or lower plate.

Description

Technical Field

[0001] This invention relates to a slit mold coating machine, and more particularly, to a slit mold coating machine with an improved gasket. This application claims priority to Korean Patent Application No. 10-2021-0166221, filed November 26, 2021, and Korean Patent Application No. 10-2022-0038990, filed March 29, 2022, the disclosures of which are incorporated herein by reference. Background Technology

[0002] With the continuous development of technology and the increasing demand for mobile devices, the demand for secondary batteries as an energy source is rapidly increasing. Secondary batteries essentially consist of electrode assemblies that serve as power generation elements. These electrode assemblies include a positive electrode, a separator, and a negative electrode stacked at least once. The positive and negative electrodes are prepared by coating and drying positive and negative active material slurries onto current collectors made of aluminum foil and copper foil, respectively. Generally, secondary batteries include lithium oxide with a layered crystal structure (LiCoO2), lithium oxide with a manganese structure (e.g., LiMnO2 with a layered crystal structure and LiMn2O4 with a spinel crystal structure), and lithium oxide with a nickel structure (LiNiO2) used as positive electrode active materials. Furthermore, carbon-based materials are primarily used as negative electrode active materials. Recently, with the increasing demand for high-energy lithium secondary batteries, carbon-based materials can be used in combination with silicon-based or silicon oxide-based materials with an effective capacity at least 10 times greater than that of carbon-based materials. To ensure uniform charge and discharge characteristics of secondary batteries, positive and negative active material slurries need to be uniformly coated on the current collector. Slit mold coating machines have been used.

[0003] Figure 1 This is an exploded cross-sectional view of a traditional slot die coating machine. Figure 2 This is a cross-sectional view of another conventional slot die coating machine.

[0004] See Figure 1 The slot die coating machine 1 includes two die blocks 5 and 10, and a slot 20 is formed between the two die blocks 5 and 10 by a spacer 15. The active material slurry in the manifold 25 exits from the outlet port communicating with the slot 20 and is coated on the current collector (not shown).

[0005] See Figure 2 The slot die coating machine 50 includes three die blocks 55, 60, and 65, and a spacer 15 is positioned between every two die blocks to form two slots 20.

[0006] Figure 3 This is a top view of a conventional gasket 15 that can be applied to slot die coating machines 1 and 50.

[0007] The coating width of the active material layer coated on the current collector is determined by the width of the slit 20 of the slit die coater 1, 50, and since the slit 20 is defined by the gasket 15, the width W of the slit 20 is determined by the shape of the gasket 15. Figure 3 The gasket 15 shown in is configured to coat, for example, a three-channel striped pattern.

[0008] Figure 4 is Figure 2 An enlarged view of region A in. Inside the die block 60, there is a manifold 25 to accommodate the active material slurry or coating solution. The front end 25a of the manifold 25, that is, the end facing the outlet port, has a circular cross-section.

[0009] Figure 5 Multi-channel coating is shown, for example, using the Figure 1 gasket 15 installed in the Figure 3 slit die coater 1 for three-channel coating. When the gasket 15 is well-aligned with the die blocks 5, 10 and the die blocks 5, 10 are not deformed, the width a of the active material layer on the current collector 70 is equal to the designed width W of the gasket 15 (a = W).

[0010] However, if there is a misinstallation of the gasket 15, deformation of the die blocks 5, 10, or a significant change in the properties of the active material slurry used for coating, the width of the coated active material layer may actually be different from the designed width W of the gasket 15.

[0011] Figure 6 Shows the change in the width of the coating on the current collector when a conventional gasket is misinstalled at an angle. For example, when the gasket 15 shown in Figure 6 is misinstalled at an angle, the widths b, b', b'' of the multiple active material layers 75 on the current collector 70 are different from each other, and each width b, b', b'' is different from the designed width W of the gasket 15 (b < W). As shown in Figure 6 the lower right corner, when the gasket 15 is misinstalled away from the die blocks 5, 10, the width of the active material layer 75 increases from b to b'' (b < b' < b'').

[0012] When a width mismatch is found, it is necessary to adjust the position of the gasket 15 to make the width of the multi-channel coating uniform. However, although there are multiple channels, the gasket 15 itself is a single (integrated channel) gasket, so the adjustment will affect all channels, and it is difficult to adjust only a single channel.

[0013] In addition, when changing the die, the gasket 15 must be separated and cleaned, and for subsequent production, it is always necessary to reassemble and adjust the state. Since the position of the gasket 15 is not always the same each time it is assembled, it is necessary to adjust the state each time the die is disassembled, cleaned, and then reassembled. Summary of the Invention

[0014] Technical issues

[0015] The present invention aims to solve the above problems. Therefore, the present invention aims to make the coating width of the multi-channel model uniform and reduce the state adjustment loss in subsequent production.

[0016] Therefore, the present invention aims to provide a slit mold coating machine including an improved gasket.

[0017] However, the technical problems to be solved by the present invention are not limited to those described above, and those skilled in the art will clearly understand these and other problems from the following description.

[0018] Technical solution

[0019] To solve the above problems, a slit mold coating machine of the present invention includes: an upper plate; a lower plate; and a gasket, the gasket being placed between the upper plate and the lower plate and defining at least two separate channels to form a slit, wherein the gasket defining a single channel includes a fixing pin for improving positioning accuracy when fixed to the upper plate or the lower plate and a fixing bolt for fixing to the upper plate or the lower plate.

[0020] The slot die coating machine may also include a manifold for holding the coating solution in the lower plate, a gasket that can be mounted on a platform in front of the manifold, a retaining pin that can pass through the gasket and be inserted into a pin groove in the lower plate, and a retaining bolt that can pass through the gasket and be inserted into a retaining bolt groove in the lower plate.

[0021] The gasket may have a fixing bolt hole aligned with the fixing bolt slot, and the fixing bolt hole and fixing bolt slot may have a allowance in the conveying direction, but may not have a allowance in the longitudinal direction of the slot die coating machine perpendicular to the conveying direction.

[0022] The upper plate may have an upper plate groove for accommodating the bolt head of the fixing bolt and the pin head of the fixing pin.

[0023] The upper plate groove can be a recess in the upper plate to simultaneously accommodate the bolt head of the fixing bolt and the pin head of the fixing pin.

[0024] A portion of the gasket that comes into contact with the manifold can be circular.

[0025] Depending on the position of the gasket on the lower plate, a circular treatment is applied to a portion of the gasket that contacts the manifold. One side of the gasket through which the coating solution flows may be circular, and a portion of the gasket that does not contact the coating solution may not be circular.

[0026] The transition point from the manifold to the platform section can be at a right angle.

[0027] Furthermore, the area where the coating solution flows and flows out between the manifold and the platform section can be circular.

[0028] The gasket can define at least three channels, and there can be a difference in the R-value of the circular processing between the center channel and the side channels.

[0029] The R-value of the side channel can be greater than that of the center channel.

[0030] In this invention, there is a height difference between the rear part of the manifold and the platform part in front of the manifold, which is formed by the thickness of the gasket.

[0031] The lower surface of the upper plate and the upper surface of the lower plate can be coupled without gap between the rear of the manifold, the lower surface of the upper plate and the upper surface of the gasket can be coupled without gap between the front of the manifold, and the upper surface of the lower plate and the lower surface of the gasket can be coupled without gap between the front of the manifold.

[0032] Beneficial effects

[0033] According to the present invention, the gasket used in the multi-channel structure is not a single mass block and can be separated individually. Therefore, when the gasket is installed, only a single channel is affected, and adjustments can be made for each individual channel.

[0034] According to the present invention, the gasket can be mounted on the platform portion in front of the manifold and fixedly mounted on the lower plate. Since there is no gasket near the manifold, it is not necessary to separate the gasket during cleaning as with conventional gaskets. No reassembly process is required after separation, thereby reducing conditioning losses.

[0035] According to the present invention, the portion of the gasket that contacts the manifold is circular, and the front end of the manifold at the transition from the manifold to the platform portion is at a right angle, thereby preventing the generation of turbulence and achieving smooth flow of the coating solution. Attached Figure Description

[0036] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the following detailed description, are intended to provide a further understanding of the technical aspects of the invention. Therefore, the invention is not to be construed as being limited to the drawings.

[0037] Figure 1 This is an exploded cross-sectional view of a traditional slot die coating machine.

[0038] Figure 2 This is an exploded cross-sectional view of another traditional slot die coating machine.

[0039] Figure 3 This is a top view of a traditional gasket.

[0040] Figure 4 yes Figure 2 A magnified view of region A in the middle.

[0041] Figure 5 It shows the way Figure 3 Multi-channel coating is applied to the installed gaskets.

[0042] Figure 6 This shows the change in the width of the coating on the current collector when the conventional gasket is misaligned.

[0043] Figure 7 This is an exploded cross-sectional view of a slot die coating machine according to an embodiment of the present invention.

[0044] Figure 8 This is an exploded cross-sectional view of a slot die coating machine according to another embodiment of the present invention.

[0045] Figure 9 yes Figure 7 A magnified view of the central area B.

[0046] Figure 10 This is a perspective view of a gasket defining a single channel in a slot die coating machine according to the invention.

[0047] Figure 11 A gasket defining a single channel is shown in a slot die coating machine according to the invention, arranged at predetermined intervals on a lower plate.

[0048] Figure 12 A cross-section of the manifold of a slot die coating machine according to another embodiment of the present invention is shown.

[0049] Figure 13 The circular portion of the gasket that contacts the manifold in a slot die coating machine according to the present invention is shown. Detailed Implementation

[0050] Hereinafter, exemplary embodiments of the present invention 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 and dictionary meanings, but should be interpreted according to their meanings and concepts corresponding to the technical aspects of the present invention, in accordance with the principle that the inventors are allowed to define terms appropriately for the best interpretation. Therefore, the embodiments described herein and the illustrations in the accompanying drawings are merely exemplary embodiments of the present invention and do not fully describe the technical aspects of the present invention. Consequently, it should be understood that various other equivalents and modifications can be made thereto when filing a patent application.

[0051] Similar reference numerals indicate similar elements. Furthermore, in the accompanying drawings, elements are depicted with exaggerated thickness, scale, and size to effectively illustrate the technical subject matter.

[0052] The slit mold coating machine of the present invention is an apparatus having a slit for coating a coating solution onto a substrate through the slit. In the following description, "substrate" is a current collector, and "coating solution" is an active material slurry. However, the scope of protection of the present invention is not necessarily limited thereto. For example, the substrate can be a porous support for a diaphragm, and the coating solution can be an organic substance. That is, any type of substrate and coating solution can be used where thin film coating is required.

[0053] The slit mold coating machine according to the present invention includes an upper plate, a lower plate, at least two gaskets defining individual channels, retaining pins, and retaining bolts. The slit mold coating machine according to the present invention also includes at least two gaskets, retaining pins, and retaining bolts defining individual channels between the upper plate and the intermediate plate, and at least two gaskets, retaining pins, and retaining bolts defining individual channels between the intermediate plate and the lower plate. These will be described in detail below with reference to the accompanying drawings.

[0054] Figure 7 This is an exploded cross-sectional view of a slot die coating machine according to an embodiment of the present invention, and Figure 8 This is an exploded cross-sectional view of a slot die coating machine according to another embodiment of the present invention. Figure 9 yes Figure 7 A magnified view of the central area B. Figure 10 This is a perspective view of a gasket defining a single channel in a slot die coating machine according to the present invention.

[0055] See Figure 7 According to an embodiment of the present invention, a slot die coating machine 100 includes an upper plate 105, a lower plate 110, and a gasket 115 defining a separate channel.

[0056] A gasket 115 is positioned between the upper plate 105 and the lower plate 110 to form a slit 120. At least two gaskets are included. When two gaskets 115 are included, a channel is defined between the two gaskets 115. When three gaskets 115 are included, each pair of adjacent gaskets 115 defines a channel, thus defining two channels. The space between two adjacent gaskets 115 defines the slit 120.

[0057] The coating solution or active material slurry can be held in manifold 125, exiting from an outlet port communicating with slit 120, and coated onto a current collector (not shown). Although not shown in the figure, manifold 125 is connected to a coating solution supply chamber (not shown) mounted outside manifold 125, which has a feed pipe and supplies the coating solution. When manifold 125 is full of coating solution, the coating solution flow is guided along slit 120 and exits from the outlet port.

[0058] A gasket 115 is placed between the upper plate 105 and the lower plate 110 and defines the shape of the slit 120. The gasket 115 acts as a sealing ring except in the area where the outlet port is located to prevent the coating solution from leaking from the gap between the upper plate 105 and the lower plate 110, and is preferably made of a sealable material.

[0059] The gasket 115 can be fixed to either the upper plate 105 or the lower plate 110. In this embodiment, for illustrative purposes, the gasket 115 is fixed to the lower plate 110. The gasket 115 includes a retaining pin 130 to improve the positioning accuracy when the gasket 115 is fixed to the lower plate 110. In addition, the gasket 115 includes a retaining bolt 140 for fixing the gasket 115 to the lower plate 110. After the gasket 115 is fixed to the lower plate 110, the lower plate 110 is assembled with the upper plate 105, and bolts are installed at the rear of the lower plate 110 and the upper plate 105 (opposite to the area where the slit 120 is located) to assemble the lower plate 110 and the upper plate 105 together.

[0060] Most surfaces of the upper plate 105 and the lower plate 110 can be nearly perpendicular to each other. Since the upper plate 105 and the lower plate 110 form right angles at their edges, right-angled portions exist in the cross-section, and either a vertical or horizontal surface can be used as a reference surface, making them easy to manufacture or process and ensuring precision. Furthermore, when the upper plate 105 and the lower plate 110 are combined, the facing portions can support each other through high surface contact, thereby achieving improved fixation and maintenance. Moreover, when combined, the upper plate 105 and the lower plate 110 as a whole have an approximately rectangular prism shape, with only the front side from which the coating solution drains tilted towards the substrate. The upper plate 105 and the lower plate 110 are made of, for example, SUS material. Easily machinable materials such as SUS420J2, SUS630, SUS440C, SUS304, and SUS316L can be used. SUS is easy to process, inexpensive, corrosion-resistant, and can be formed into the desired shape at low cost.

[0061] By using the slit mold coating machine 100 with the above-described structure, when the substrate to be coated is moved by the rotation of a rotatable coating roller (not shown) disposed on the front side of the slit mold coating machine 100, a coating solution can be delivered and continuously coated in contact with the surface of the substrate. Alternatively, a patterned coating can be formed on the substrate intermittently by alternately supplying and stopping the supply of the coating solution.

[0062] See Figure 8According to another embodiment of the present invention, a slit mold coating machine 200 includes an upper plate 205, a lower plate 210, and an intermediate plate 207 therebetween. The slit mold coating machine 200 may include gaskets 115 as described above, located between the upper plate 205 and the intermediate plate 207, and between the intermediate plate 207 and the lower plate 210. Here, at least two gaskets 115 are included between every two mold blocks. The number of gaskets 115 may vary depending on the number of channels. Manifolds 125 may be formed in each of the intermediate plate 207 and the lower plate 210.

[0063] Since the common feature of slit mold coating machines 100 and 200 is the gasket 115, slit mold coating machine 100 will refer to Figure 7 and 9 The description proceeds up to 11. Although repeated descriptions have been omitted, it should be understood that the descriptions made herein are equally applicable to the slit mold coating machine 200.

[0064] See Figure 7 , 9 The slit mold coating machine 100 includes a manifold 125 that holds the coating solution in a lower plate 110. A gasket 115 is mounted on a platform portion 127 in front of the manifold 125.

[0065] Since the gasket 115 exists only in the platform section 127, there is a difference between the height of the rear of the manifold 125 (opposite to the outlet port) and the height of the platform section 127 in front of the manifold 125, which is determined by the thickness of the gasket 115.

[0066] The retaining pin 130 can pass through the washer 115 and be inserted into the pin groove 110a of the lower plate 110. The retaining bolt 140 can pass through the washer 115 and be inserted into the retaining bolt groove 110b of the lower plate 110.

[0067] The washer 115 has a pin hole 115a aligned with the pin groove 110a. In addition, the washer 115 has a fixing bolt hole 115b aligned with the fixing bolt groove 110b.

[0068] The fixing bolt groove 110b and fixing bolt hole 115b may have a margin in the front-to-back direction (conveying direction), and may not have a margin in the left-to-right direction (the longitudinal direction of the slit mold coating machine perpendicular to the conveying direction).

[0069] A more detailed description Figure 9 and 10The retaining pin 130 is configured to improve the positional accuracy of the shim 115. The retaining pin 130 passes through the shim 115 via the pin hole 115a and inserts into the pin groove 110a, holding the shim 115 in place after insertion. The lower plate 110 and the shim 115 can be precisely aligned using the retaining pin 130. For example, after inserting the retaining pin 130 to hold the shim 115 in place, a retaining bolt 140 can be installed. When the retaining bolt 140 is installed, the retaining pin 130 sets its position to prevent the shim 115 from moving.

[0070] The fixing bolt 140 is used to secure the washer 115 to the lower plate 110. The fixing bolt 140 passes through the washer 115 via the fixing bolt hole 115b and is inserted into the fixing bolt groove 110b. Since the fixing bolt hole 115b and the fixing bolt groove 110b have allowance in the front-to-back direction (conveyor direction), tightening and assembly are convenient. Furthermore, since there is no allowance in the left-to-right direction (the longitudinal direction of the slit mold coating machine perpendicular to the conveyor direction), horizontal movement is restricted, thereby fixing the horizontal position.

[0071] In this embodiment, the pin hole 115a through which the retaining pin 130 passes and the retaining bolt hole 115b through which the retaining bolt 140 passes are aligned in a straight line along the front-to-back direction (transmission direction). Each washer 115 may include at least one retaining pin 130 and at least one retaining bolt 140. Those skilled in the art will understand that optimal numbers and / or various configurations of retaining pins 130 and retaining bolts 140 can be used within the scope of this invention.

[0072] The retaining pin 130 and retaining bolt 140 are respectively inserted into and accommodated in the pin groove 110a and retaining bolt groove 110b via washers 115, and the lower surface of the washers 115 contacts the upper surface of the lower plate 110 in the platform portion 127. The upper surface of the lower plate 110 and the lower surface of the washers 115 can be coupled without gaps between them. Additionally, the lower surface of the upper plate 105 and the upper surface of the lower plate 110 can be coupled at the rear of the manifold 125 without gaps between them.

[0073] To accommodate the bolt head of the fixing bolt 140 and the pin head of the fixing pin 130, the upper plate 105 may have an upper plate groove 105a. The upper plate groove 105a may exist in a corresponding position to accommodate the bolt head of the fixing bolt 140 and the pin head of the fixing pin 130, but a recess may also exist in the upper plate 105 to simultaneously accommodate the bolt head of the fixing bolt 140 and the pin head of the fixing pin 130. When the upper plate groove 105a is configured to accommodate the bolt head of the fixing bolt 140 and the pin head of the fixing pin 130, aligning and positioning the upper plate 105 and the lower plate 110 may be a cumbersome operation. When the upper plate groove 105a is configured to simultaneously accommodate the bolt head of the fixing bolt 140 and the pin head of the fixing pin 130, the bolt head of the fixing bolt 140 and the pin head of the fixing pin 130 are accommodated in the upper plate groove 105a with a relatively sufficient gap, resulting in an increased alignment allowance between the upper plate 105 and the lower plate 110. With sufficient alignment allowance, subsequent assembly-related operations can be carried out more smoothly, such as assembling the upper plate 105 and the lower plate 110 with bolts.

[0074] Furthermore, when the gasket 115 is fixed to the lower plate 110 in this embodiment, the fixing bolts 140 and fixing pins 130 used for fixing do not pass through the upper plate 105. The fixing bolts 140 and fixing pins 130 are not exposed through the mold block. Additionally, the fixing bolts 140 are not installed in the upper plate 105, but only in the lower plate 110. As described above, the fixing bolts 140 and fixing pins 130 are only assembled / installed in the lower plate 110, and not assembled / installed in the upper plate 105. Therefore, to check the condition of the gasket 115 or clean the mold block, only the lower plate 110 and the upper plate 105 need to be disassembled, thereby improving convenience, and eliminating the need to disassemble and reassemble the entire slot die coating machine, thus facilitating process management.

[0075] When the upper plate groove 105a is formed, the bolt head of the fixing bolt 140 and the pin head of the fixing pin 130 are accommodated within the upper plate groove 105a, and the lower surface of the upper plate 105 and the upper surface of the gasket 115 are in contact with each other near the upper plate groove 105a. Therefore, the lower surface of the upper plate 105 and the upper surface of the gasket 115 can be coupled without gaps between them. A gap corresponding to the thickness of the gasket 115 is formed between the upper plate 105 and the lower plate 110 in front of the manifold 125; this gap is called a slit 120.

[0076] Figure 11 The diagram shows gaskets 115 arranged at predetermined intervals on a lower plate 110 in a slot die coating machine 100 according to the invention. For example, four gaskets 115 define three channels.

[0077] According to the present invention, since the gasket 115 can be individually separable, only a single channel is affected during installation, and adjustments can be made for each individual channel. The gasket 115 can be installed only on the platform portion 127 in front of the manifold 125 and can be fixedly mounted on the lower plate 110. Since there is no gasket 115 near the manifold 125, unlike conventional gaskets 15, it does not need to be separated from the mold block for cleaning (see...). Figure 3 Separation eliminates the need for reassembly, thus reducing state adjustment losses.

[0078] like Figure 10 and 11 As shown, the gasket 115 of the present invention preferably has a circular portion 115c that contacts the manifold 125 to achieve smooth flow of the coating solution or fluid, thereby preventing the generation of turbulence.

[0079] As reference Figure 4 The conventional slot die coating machine, as described, has a circular front end 25a of the manifold corresponding to the transition point from the manifold 25 to the platform section. However, the present invention has... Figure 10 The right-angled front end 125a of the manifold corresponds to the transition point from manifold 125 to platform section 127 (in cross-section). If the front end 125a of the manifold corresponding to the transition point from manifold 125 to platform section 127 is circular as in conventional processes, it will result in a lower fluid flow rate.

[0080] In this invention, the portion 115c of the gasket 115 that contacts the manifold 125 is circular, and the front end 125a of the manifold corresponding to the transition point from the manifold 125 to the platform portion 127 is at a right angle, thereby achieving smooth fluid flow.

[0081] Meanwhile, in another embodiment, see further... Figure 11 Only the regions 126a and 126b corresponding to the flow and outflow of the coating solution or active material slurry between the manifold 125 and the platform section 127 can be rounded. As previously mentioned, the front end 125a of the manifold is right-angled.

[0082] Especially in multi-channel coating, the R-value of circular processing may differ between the center and the sides, such as... Figure 12 As shown. Figure 12 A cross-section of the manifold of a slot die coating machine according to another embodiment of the present invention is shown. Figure 12 In the middle, (a) is Figure 11 (a) is a cross-sectional view extracted along line "II"; (b) is Figure 11 A cross-sectional view extracted along line "II-II". Assuming... Figure 11 As shown, three channels are defined by gasket 115.

[0083] See Figure 12 (a) The central channel, i.e., the central region 126a between the manifold 125 and the platform section 127 where the coating solution or active material slurry flows and flows out, has a smaller R value. (See reference) Figure 12 (b) The side channel, namely the central region 126a between the manifold 125 and the platform section 127 where the coating solution or active material slurry flows and flows out, has a larger R value. Therefore, the flow difference between the center and the side can be reduced.

[0084] at the same time, Figure 10 The portion 115c of the gasket 115 that contacts the manifold 125 is shown to have rounded sides, but the rounded treatment can be applied differently depending on the position of the gasket 115 on the lower plate 110. Figure 13 The circular portion of the gasket that contacts the manifold in a slot die coating machine according to the present invention is shown.

[0085] See Figure 13 The gasket 115 is circular only on the outermost edge, corresponding to the inner side where the coating solution or active material slurry flows. The outer side, which is not in contact with the coating solution, may not be circular. The centrally located gasket 115 can be circular on both sides where the coating solution flows. Therefore, the risk of turbulence in the corresponding area can be further reduced.

[0086] For example, the slit mold coating machine 100 of the present invention can be used to coat a positive electrode active material slurry to manufacture a positive electrode for a secondary battery. The positive electrode includes a current collector and a layer of positive electrode active material located on the surface of the current collector. The current collector may include conductive materials, such as Al and Cu, and a suitable current collector may be used according to the polarity of current collector electrodes 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. Furthermore, the positive electrode may further include various types of additives to supplement or improve electrical and chemical properties.

[0087] The active material is not limited to a specific type and may include any type of active material that can be used as a positive electrode active material in lithium-ion secondary batteries. Non-limiting embodiments may include at least one of layered compounds or compounds having one or more transition metal substitutions, such as lithium manganese composite oxides (LiMn2O4, LiMnO2), lithium cobalt oxide (LiCoO2), and lithium nickel oxide (LiNiO2); Li 1+x Mn 2-x Lithium manganese oxides such as O4 (x = 0-0.33), LiMnO3, LiMn2O3, and LiMnO2; lithium copper oxide; vanadium oxides such as LiV3O8, LiV3O4, V2O5, and Cu2V2O7; and lithium NiO2. 1-x M xNi-site lithium nickel oxides represented by O2 (M = Co, Mn, Al, Cu, Fe, Mg, B or Ga, x = 0.01-0.3); LiMn 2-x M x Lithium-manganese composite oxides represented by O2 (M = Co, Ni, Fe, Cr, Zn or Ta, x = 0.01-0.1) or Li2Mn3MO8 (M = Fe, Co, Ni, Cu or Zn); LiMn2O4 with Li partially substituted by alkaline earth metal ions; disulfide compounds; or Fe2(MoO4)3. In this invention, the positive electrode may include a solid electrolyte material, for example, at least one of polymer-based solid electrolytes, oxide-based solid electrolytes, or sulfide-based solid electrolytes.

[0088] 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 particular type and may include any material that has conductive properties without causing any chemical change in the corresponding battery, such as at least one material selected from graphite, for example, natural or artificial graphite; carbon black, such as carbon black, acetylene black, conductive carbon black, channel black, furnace black, lamp black, thermally conductive black, etc.; conductive fibers, such as carbon fibers or metal fibers; metal powders, such as fluorinated carbon, aluminum and nickel powder; conductive whiskers, such as zinc oxide and potassium titanate; conductive metal oxides, such as titanium oxide; and conductive materials, such as polystyrene derivatives.

[0089] The adhesive is not limited to a specific type and may include any material that helps to bond the active and conductive materials together and to the current collector, such as polyvinylidene fluoride polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylidene fluoride pyridone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, butadiene rubber, fluororubber, and various copolymers thereof. Depending on 100 wt% of the electrode layer, the adhesive may typically be included in the range of 1 wt% to 30 wt% or 1 wt% to 10 wt%.

[0090] The slit mold coating machine 100 of the present invention can be used to coat a negative electrode active material slurry to manufacture a negative electrode for a secondary battery. The negative electrode includes a current collector and a layer of negative electrode active material located on the surface of the current collector. The negative electrode active material layer may further contain at least one of a plurality of negative electrode active material particles, a conductive material, or a binder. Furthermore, the negative electrode may further include various additives to supplement or improve its electrical and chemical properties.

[0091] Negative electrode active materials can include carbon materials, such as graphite, amorphous carbon, diamond-like carbon, fullerenes, carbon nanotubes and carbon nanotubes, lithium metal materials, alloy-based materials, such as silicon or tin alloy-based materials, and oxide-based materials, such as Nb₂O₅ and Li₅Ti₄O₂. 12 TiO2 or the aforementioned composite materials. For details regarding conductive materials, binders, and negative electrode current collectors, please refer to the description of the positive electrode.

[0092] The active material slurry includes positive or negative electrode active materials and has a very high viscosity. For example, the viscosity can be 1000 cps or higher. The viscosity of the active material slurry used to form the electrode of a secondary battery can be 2000 cps to 30000 cps. For example, the viscosity of the negative electrode active material slurry can be 2000 cps to 4000 cps. The viscosity of the positive electrode active material slurry can reach 8000 cps to 30000 cps. Because a coating solution with a viscosity of 1000 cps or higher is required, the slit mold coating machine 100 of the present invention is structurally different from devices that coat any other coating solution with a lower viscosity, such as common resin solutions, like photosensitive emulsions, magnetic solutions, anti-reflective or anti-glare solutions, solutions for expanding the field of view, and pigment solutions for color filters. The slit mold coating machine 100 of the present invention cannot be achieved by modifying the design. For example, because the slit mold coating machine 100 of the present invention is designed for coating active material slurries containing active materials with an average particle size of about 10 micrometers (μm), its structure differs from that of any other coating solution that does not contain particles having the aforementioned particle size, and cannot be achieved through design modifications. The slit mold coating machine 100 of the present invention is the optimal coating machine for manufacturing electrodes.

[0093] Although the above description is based on the slit mold coating machine 100, the structure associated with the gasket 115 can be equally applied to the slit mold coating machine 200. See also Figure 8 The description relating to the upper plate 105 and lower plate 110 of the slit mold coating machine 100, and the gasket 115 between the upper plate 105 and lower plate 110, also applies to the upper plate 205 and intermediate plate 207 of the slit mold coating machine 200, and the gasket 115 between the upper plate 205 and intermediate plate 207. For example, a pin groove 110a and a fixing bolt groove 110b of the lower plate 110 are formed in the intermediate plate 207. Furthermore, the description relating to the upper plate 105 and lower plate 110 of the slit mold coating machine 100, and the gasket 115 between the upper plate 105 and lower plate 110, also applies to the intermediate plate 207 and lower plate 210 of the slit mold coating machine 200, and the gasket 115 between the intermediate plate 207 and lower plate 210. The shims 115 between the upper plate 205 and the middle plate 207 and between the middle plate 207 and the lower plate 210 can be set in a vertically aligned position.

[0094] Simultaneously, slit mold coating machines 100 and 200 are installed so that the conveying direction of the coating solution or electrode active material slurry is almost horizontal (almost ±50 degrees). However, the invention is not limited to the exemplary configuration, and for example, a vertical mold configuration may be used to convey the electrode active material slurry from bottom to top, i.e., in the opposite direction of gravity.

[0095] While the present invention relates to a limited number of embodiments and drawings, it is not limited thereto, and various changes and modifications may be apparent to those skilled in the art in relation to the invention and the appended claims and their equivalents.

[0096] [Explanation of reference numerals in the attached figures]

[0097] 100, 200: Slit mold coating machine; 105, 205: Upper plate

[0098] 105a: Upper plate slot 110, 210: Lower plate

[0099] 110a: Pin groove; 110b: Fixing bolt groove

[0100] 115: Gasket; 115a: Pin hole

[0101] 115b: Fixing bolt hole; 120: Slit

[0102] 125: Manifold 127: Platform Department

[0103] 130: Fixing pin; 140: Fixing bolt

[0104] 207: Intermediate Plate

Claims

1. A slot die coating machine, comprising: upper plate; Lower board; A manifold for holding a coating solution in the lower plate; as well as A gasket is placed between the upper plate and the lower plate and defines at least two separate channels to form a slit; The gasket includes a retaining pin for improving positioning accuracy when fixed to the upper plate or the lower plate, and a retaining bolt for fixing to the upper plate or the lower plate. The gasket is mounted on the platform portion in front of the manifold. The fixing bolt passes through the washer and is inserted into the fixing bolt groove of the lower plate, and The gasket has a fixing bolt hole aligned with the fixing bolt slot, and the fixing bolt hole and the fixing bolt slot have a margin in the conveying direction but no margin in the longitudinal direction perpendicular to the conveying direction of the slot die coating machine.

2. The slit mold coating machine according to claim 1, wherein the fixing pin passes through the gasket and is inserted into the pin groove of the lower plate.

3. The slit mold coating machine according to claim 1, wherein the upper plate has an upper plate groove for receiving the bolt head of the fixing bolt and the pin head of the fixing pin.

4. The slit mold coating machine according to claim 3, wherein the upper plate groove is a recess in the upper plate to simultaneously accommodate the bolt head of the fixing bolt and the pin head of the fixing pin.

5. The slot die coating machine according to claim 1, wherein a portion of the gasket in contact with the manifold is circular.

6. The slot die coating machine according to claim 5, wherein the circular treatment of a portion of the gasket in contact with the manifold is applied differently depending on the position of the gasket placed on the lower plate.

7. The slot die coating machine according to claim 6, wherein one side of the gasket through which the coating solution flows is circular, and a portion of the gasket that is not in contact with the coating solution is not circular.

8. The slot die coating machine according to claim 1, wherein the transition point from the manifold to the platform section is at a right angle.

9. The slot die coating machine according to claim 8, wherein the area where the coating solution flows and exits between the manifold and the platform section is circular.

10. The slit mold coating machine of claim 9, wherein the gasket defines at least three channels and there is a difference in the R-value of the circular treatment between the central channel and the side channels.

11. The slit mold coating machine according to claim 10, wherein the R value in the channel on the side is greater than the R value in the channel at the center.

12. The slot die coating machine according to claim 1, wherein the height difference between the platform portion at the rear of the manifold and the front of the manifold is the thickness of the gasket.

13. The slot die coating machine according to claim 12, wherein the lower surface of the upper plate and the upper surface of the lower plate are coupled without gap between the rear portion of the manifold, the lower surface of the upper plate and the upper surface of the gasket are coupled without gap between the front portion of the manifold, and the upper surface of the lower plate and the lower surface of the gasket are coupled without gap between the front portion of the manifold.

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