Die coater, coating equipment including same, and electrode coating method using same

Abstract

The die coater of the present invention is characterized in that in a second coater shim that forms a second slit through which insulating liquid is ejected, the length L1 of the first side wall located relatively far from the first slit is longer than the length L2 of the second side wall located relatively close to the first slit.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2023-0174268, filed on December 5, 2023.

[0002] The present invention relates to a die coater for simultaneously coating an electrode with a slurry and an insulating liquid, a coating facility including the die coater, and a method for coating an electrode using the die coater. [Background technology]

[0003] The demand for secondary batteries is also increasing rapidly due to technological developments and increased demand for mobile devices. Among them, lithium secondary batteries are widely used as an energy source for various electronic products as well as various mobile devices due to their high energy density, operating voltage, and excellent storage and life characteristics.

[0004] Lithium secondary batteries use electrodes in which an active material layer and an insulating layer are formed on the surface of a current collector. Such electrodes are manufactured by applying an electrode slurry containing active materials and an insulating liquid containing insulating materials to the surface of a current collector using a coating device such as a die coater, so that the corners of the electrode active material layer overlap, and then drying the applied slurry.

[0005] A double-sided electrode, in which electrode active material layers are disposed on both sides of a current collector, is manufactured through a top-coating process in which electrode slurry and insulating liquid are coated on the first surface, which is the front surface of the current collector, followed by a back-coating process in which electrode slurry and insulating liquid are coated on the second surface, which is the back surface of the current collector.

[0006] FIG. 1 is an exploded perspective view of a conventional die coater, FIG. 2 is a front view of the conventional die coater, and FIG. 4 is a cross-sectional view of a portion of an electrode obtained by performing a back coating process using the conventional die coater.

[0007] Referring to Figures 1 and 2, in a conventional die coater 1, in the second coater shim 5 that forms the second slit 7 through which the insulating liquid is ejected, the first side wall 5a and the second side wall 5b that extend parallel to the first direction (Z direction), which is the ejection direction of the insulating liquid, have the same length.

[0008] When such a conventional die coater 1 is used to perform a back coating process in which electrode slurry and insulating liquid are coated on the second surface, which is the back surface of the current collector, a fat edge portion FE is generated in the insulating liquid layer IL, as shown in Figure 4.

[0009] The fat edge portion can cause interference during cell assembly due to its protruding shape, and reducing the overall thickness of the insulating liquid coating to resolve this issue can pose a safety issue. Therefore, technological development is needed for coating equipment and coating methods that prevent the formation of fat edges in the insulating liquid layer during the backcoating process of double-sided electrodes. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Korean Patent Publication No. 10-2020-0049640 Summary of the Invention [Problem to be solved by the invention]

[0011] The technical idea of ​​the present invention aims to provide a die coater, a coating equipment including the same, and a coating method that prevent fat edges from occurring in an insulating liquid layer during a back coating process for a double-sided electrode. [Means for solving the problem]

[0012] According to one embodiment of the present invention, a die coater is provided.

[0013] The die coater includes a first block having a manifold for containing electrode slurry, a second block coupled to the first block, and a coater shim interposed between the first block and the second block, the coater shim including a first coater shim forming a first slit for ejecting the electrode slurry and at least one second coater shim forming a second slit for ejecting an insulating liquid, the second coater shim having a pair of first and second side walls extending along a first direction which is the ejection direction of the insulating liquid, and with respect to a second direction perpendicular to the first direction, the length L1 of the first side wall located on the outer side is longer than the length L2 of the second side wall located on the inner side.

[0014] In an exemplary embodiment, the plane of the second slit is tilted relative to the plane of the first slit.

[0015] In the exemplary embodiment, one end of the first side wall in the first direction protrudes outward from the tip ends of the first block and the second block.

[0016] In the exemplary embodiment, one end of the second side wall in the first direction is located inward from the tip ends of the first block and the second block.

[0017] In an exemplary embodiment, the width of the first slit is limited by the width of the second coater shim.

[0018] In an exemplary embodiment, the height of the first slit corresponds to the height of the first coater shim, and the height of the second slit is less than the height of the second coater shim.

[0019] In an exemplary embodiment, one of the first block and the second block includes an insulating liquid inlet pipe for supplying insulating liquid.

[0020] In an exemplary embodiment, the second coater shim includes a recessed insulating liquid flow channel having a bottom surface that is open toward the first block.

[0021] In an exemplary embodiment, the second coater shim is positioned so as not to overlap the manifold of the first block.

[0022] In an exemplary embodiment, an insulating liquid supply hole is disposed at the closed end of the insulating liquid flow channel, and the open end of the insulating liquid flow channel forms the second slit.

[0023] In an exemplary embodiment, one end of the insulating liquid inlet pipe is connected to the insulating liquid supply hole.

[0024] In an exemplary embodiment, the second coater shim is fixedly coupled to one or more of the first block and the second block.

[0025] In an exemplary embodiment, the first coater shim includes a base extending along the second direction, and a first guide and a second guide extending and protruding from opposite ends of the base, the first guide and the second guide being spaced apart with the manifold therebetween.

[0026] In an exemplary embodiment, the first guide and second guide are spaced apart so as not to cover the manifold.

[0027] In an exemplary embodiment, there are two or more second coater shims, and the second coater shims are arranged such that the second slits are located on edges of the first slits in the second direction.

[0028] Another embodiment of the present invention provides coating equipment, including a die coater configured to simultaneously discharge an electrode slurry and an insulating liquid, and a coating roller configured to rotate to transport an electrode substrate, the die coater including a first block having a manifold for accommodating the electrode slurry, a second block coupled to the first block, and a coater shim interposed between the first block and the second block, the coater shim including a first coater shim forming a first slit for discharging the electrode slurry and a second coater shim forming a second slit for discharging the insulating liquid, the second coater shim including a pair of first and second side walls extending along a first direction that is a discharging direction of the insulating liquid, and a length L1 of the first side wall located on an outer side is longer than a length L2 of the second side wall located on an inner side, based on a second direction perpendicular to the first direction.

[0029] According to another embodiment of the present invention, a method for coating an electrode is provided.

[0030] The coating method of the present invention includes a top-coating step of coating a first surface of a current collector with an electrode slurry and an insulating liquid, and a back-coating step of coating a second surface of the current collector with an electrode slurry and an insulating liquid, and the back-coating step uses the above-mentioned coating equipment. [Effects of the Invention]

[0031] According to an exemplary embodiment of the present invention, when backcoating is performed, the coating gap, which is the distance between the tip of the second coater shim that forms the second slit through which the insulating liquid is ejected and the current collector, which is the electrode substrate, is constant along the width direction, so fat edges do not occur in the insulating liquid layer, and an insulating layer with a uniform coating thickness can be formed.

[0032] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by a person having ordinary skill in the art from the following description. [Brief explanation of the drawings]

[0033] [Figure 1] FIG. 1 is an exploded perspective view of a conventional die coater. [Figure 2] FIG. 1 is a front view of a conventional die coater. [Figure 3] 1 is a diagram for explaining problems that arise when a back coating process is performed using a conventional die coater. [Figure 4] 1 is a cross-sectional view of a portion of an electrode manufactured by performing a back coating process using a conventional die coater. [Figure 5] 1 is a view illustrating a back coating process performed using a coating equipment according to an exemplary embodiment of the present invention; [Figure 6] FIG. 1 is an exploded perspective view of a die coater according to an exemplary embodiment of the present invention. [Figure 7] FIG. 7 is a front view of the die coater of FIG. 6. [Figure 8] FIG. 7 is a plan view of the die coater seen through the first block of FIG. 6. [Figure 9] 9A and 9B are an enlarged plan view and a front view showing part "A" in FIG. 8. [Figure 10] 1 is an enlarged view of the periphery of a second coater shim in a coating facility according to an exemplary embodiment of the present invention. [Figure 11] 1 is a cross-sectional view of a portion of an electrode manufactured by performing a back coating process using the die coater of the present invention. [Figure 12] 1 is a schematic diagram illustrating a coating method according to an exemplary embodiment of the present invention. [Figure 13] FIG. 1 is an exploded perspective view of a die coater according to an exemplary embodiment of the present invention. [Figure 14] FIG. 14 is a front view of the die coater of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Before that, it should be noted that the terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to best describe his / her invention.

[0035] Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and there may be various equivalents and modifications that can replace them at the time of this application.

[0036] Furthermore, in the description of the present invention, if it is determined that a specific description of related publicly known configurations or functions may obscure the gist of the present invention, the detailed description will be omitted.

[0037] The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and therefore the shapes and sizes of components in the drawings may be exaggerated, omitted, or shown in a schematic manner for clearer explanation. Therefore, the sizes and proportions of each component do not completely reflect the actual sizes and proportions.

[0038] As used herein, singular expressions include plural expressions unless the context clearly dictates otherwise.

[0039] In this specification, the first direction is the ejection direction of the electrode slurry or insulating liquid and is defined as the Z direction, and the second direction is the width direction of the die coater and is a direction perpendicular to the first direction and is defined as the Y direction.

[0040] The present invention relates to a die coater capable of simultaneously coating two different types of liquid onto an electrode substrate of an electrode for a secondary battery, a coating facility including the same, and a coating method.

[0041] FIG. 3 illustrates a problem that occurs when a backcoating process is performed using a die coater. The inventors of the present invention discovered that the occurrence of fat edges is due to the difference in thickness between the electrode slurry layer ES and the insulating liquid layer IL coated on the first surface of the current collector F after the top coating process. Referring to FIG. 3, in a conventional die coater, the coating gaps G1 and G2, which are the distances between the tips of the first and second blocks 2 and 3 onto which the insulating liquid is discharged during backcoating and the current collector F, are not constant but vary along the second direction (Y direction). Specifically, the coating gaps G1 and G2 gradually increase from the electrode slurry layer ES toward the insulating liquid layer IL. Performing the backcoating process under these conditions results in a fat edge FE, where the coating thickness is relatively thick, in a portion of the insulating liquid layer formed on the second surface of the current collector, as shown in FIG. 4.

[0042] In a die coater according to an exemplary embodiment of the present invention, the structure of a second coater shim, which forms a second slit for discharging insulating liquid, is redesigned differently from conventional techniques to prevent the occurrence of fat edges in the insulating liquid layer during the back-coating process for manufacturing double-sided electrodes. The inventors of the present invention noticed that in double-sided electrodes, fat edges do not occur in both the insulating liquid layer on the first side and the insulating liquid layer on the second side, but only in the insulating liquid layer on the second side. After years of research, they discovered that the cause of the problem was the difference in the coating gap, as described above. To solve this problem, they redesigned the second coater shim to maintain a constant coating gap during back-coating. That is, they redesigned the die coater to compensate for the difference in thickness between the electrode slurry layer applied to the first side and the insulating liquid layer.

[0043] (First embodiment) Figure 5 is a drawing showing how a back coating process is performed using coating equipment according to an exemplary embodiment of the present invention, Figure 6 is an exploded oblique view of a die coater according to an exemplary embodiment of the present invention, Figure 7 is a front view of the die coater of Figure 6, Figure 8 is a plan view of the die coater seen through the first block of Figure 6, Figure 9 is a plan view and front view showing an enlarged view of part "A" of Figure 8, and Figure 10 is an enlarged view of the area around the second coater shim in coating equipment according to an exemplary embodiment of the present invention.

[0044] Referring to FIG. 5, a coating equipment according to an exemplary embodiment of the present invention includes a die coater 10 and a coating roller 20 .

[0045] The die coater 10 is configured to simultaneously eject the electrode slurry ES and the insulating liquid (not shown) onto the current collector F, which is the electrode substrate, and the coating roller 20 is configured to rotate to transport the electrode substrate in one direction.

[0046] Referring to Figures 6 to 8, the die coater 10 according to an exemplary embodiment includes a first block 200 having a manifold 210 for containing electrode slurry, a second block 100 coupled to the first block 200, and a coater shim 300 interposed between the first block 200 and the second block 100.

[0047] Here, the coater shim 300 of the present invention includes a first coater shim 310 and a second coater shim 320. While the above drawings illustrate an embodiment in which the second coater shim 320 is configured to be connectable and detachable to the first coater shim 310, the present invention is not limited thereto. That is, the first coater shim 310 and the second coater shim 320 may be integral. The first coater shim 310 may have a first slit 410 for discharging electrode slurry contained in the manifold 210 of the first block 200, and the second coater shim 320 may have a second slit 420 for discharging insulating liquid supplied through the insulating liquid inlet pipe 110. The second coater shim 320 is positioned so that the second slit 420 is located at the edge of the first slit 410 in the second direction (Y direction). This allows insulating liquid to be applied to the edge of the electrode slurry application portion in the second direction. The number of second coater shims 320 is determined according to the number of rows to which the insulating liquid is applied, and may be, for example, one, or two or more.

[0048] In particular, in the die coater 10 of the present invention, in order to prevent the occurrence of fat edges in the insulating liquid layer, the second coater shim 320 is designed differently from conventional ones so that during the back coating process, the coating gap, which is the distance between the tip of the second coater shim 320 that forms the second slit 420 and the electrode substrate, is constant along the second direction (Y direction), which is the width direction of the die coater.

[0049] 7 to 9, the second coater shim 320 includes a pair of first and second side walls 321 and 322 extending along a first direction (Z direction) that is a direction in which the insulating liquid is discharged. In the second coater shim 320, the first side wall 321 is located on the outer side with respect to the second direction (Y direction), and the second side wall 322 is located on the inner side. A length L1 of the first side wall 321 is longer than a length L2 of the second side wall 322.

[0050] 10, even if there is a difference in thickness between the electrode slurry layer ES coated on the first surface of the current collector F and the insulating liquid layer IL, the coating gap, which is the distance from the tip of the second coater shim 320 that forms the second slit 420 through which the insulating liquid is discharged to the current collector F, which is the electrode substrate, is constant along the second direction (Y direction). Therefore, when the back coating process is performed using the die coater 10 of the present invention, fat edges do not occur in the insulating liquid layer IL coated on both surfaces, as shown in FIG.

[0051] In an exemplary embodiment, the first block 200 may include a manifold 210 for containing electrode slurry. The second block 100 coupled to the first block 200 may include an insulating liquid inlet pipe 110 for receiving an insulating liquid from the outside. The first block 200 and the second block 100 each occupy approximately half of the main body of the die coater 10.

[0052] 6 shows the electrode slurry inlet 120 communicating with the manifold 210 of the first block 200 as being formed in the second block 100, but the electrode slurry inlet 120 may be formed in the first block 200. Also, in FIG. 6, the insulating liquid inlet pipe 110 for supplying the insulating liquid is shown as being formed in the second block 100, but the insulating liquid inlet pipe 110 may be formed in the first block 200.

[0053] The coater shims 300 (first coater shim 310, second coater shim 320) are interposed between the first block 200 and the second block 100 and form slits of a height suitable for discharging the electrode slurry and insulating liquid. The coater shims 300 (first coater shim 310, second coater shim 320) restrict the flow direction of the liquids flowing into the die coater 10 or contained in the die coater 10 so that they are discharged toward the slits without flowing back, and also serve to seal the liquids so that they do not leak into areas other than the slits.

[0054] The present invention includes a first coater shim 310 and a second coater shim 320 as the coater shim 300, and the first coater shim 310 and the second coater shim 320 form a first slit 410 and a second slit 420 that are separated from each other. Specifically, the first coater shim 310 forms the first slit 410 for discharging the electrode slurry contained in the manifold 210 of the first block 200, and the second coater shim 320 forms the second slit 420 for discharging the insulating liquid supplied through the insulating liquid inlet pipe 110 of the second block 100.

[0055] The first coater shim 310 and the second coater shim 320 have the same height and do not overlap one another. Therefore, the first coater shim 310 and the second coater shim 320 are placed on the same plane between the first block 200 and the second block 100. The first coater shim 310 and the second coater shim 320 are each coupled and fixed to one or more of the first block 200 and the second block 100. Therefore, the first coater shim 310 and the second coater shim 320 are tightly sealed at their upper and lower surfaces to the first block 200 and the second block 100, respectively, due to the pressure applied by fastening the first block 200 and the second block 100, for example, by bolt fastening (not shown).

[0056] The first coater shim 310 includes a base 312 extending in the second direction (Y direction), and a first guide 314 and a second guide 316 extending and protruding from both ends of the base 312. Here, the first coater shim 310 forms a space between the first guide 314 and the second guide 316 as a first slit 410. The first guide 314 and the second guide 316 are spaced apart with the manifold 210 therebetween and are disposed so as not to cover the manifold 210. As a result, the electrode slurry contained in the manifold 210 is discharged to the outside through the first slit 410 formed by the first coater shim 310, the first block 200, and the second block 100.

[0057] In the exemplary embodiment, the second coater shim 320 is open toward the first block 200 and has a recessed insulating liquid flow groove 323 with a bottom (see FIG. 9(b)). In the second coater shim 320, the open end of the groove-shaped insulating liquid flow groove 323 forms a second slit 420. Since the depth of the insulating liquid flow groove 323 is smaller than the thickness (height) of the second coater shim 320, the height of the first slit 410 corresponds to the height of the first coater shim 310, and the height of the second slit 420 is smaller than the height of the second coater shim 320, as shown in FIG. 7. Here, the "height" refers to the length in the X direction. In the second coater shim 320, the insulating liquid flow groove 323 faces toward the first block 200, and therefore the second slit 420 is defined as the space formed between the insulating liquid flow groove 323 and the first block 200.

[0058] The first coater shim 310 and the second coater shim 320 have the same height and are placed on the same plane without being stacked one on top of the other, so that the width of the first slit 410 is limited by the width of the second coater shim 320 .

[0059] In the exemplary embodiment, the first side wall 321 of the second coater shim 320 can be in close contact with the inner side wall of the first guide 314 or the second guide 316, respectively. As a result, the distance between the opposing second side walls 322 (sides opposite the first side walls) of a pair of second coater shims 320 corresponds to the substantial width of the first slit 410. In other words, the width of the first slit 410 is the length obtained by subtracting the width of the pair of second coater shims 320 from the distance between the inner side walls of the first guide 314 and the second guide 316.

[0060] In an exemplary embodiment, the second coater shim 320 can be positioned so as not to overlap the manifold 210 of the first block 200. Therefore, when looking at the structure of the second slit 420 formed by the second coater shim 320, both side walls 321 and 322 of the second coater shim 320 isolate the second slit 420 from the electrode slurry in the first slit 410. Furthermore, the upper side of the insulating liquid flow channel 323 is the bottom surface, while the lower side is in close contact with the flat surface of the first block 200. Consequently, the second coater shim 320 is structurally completely isolated from the electrode slurry. Therefore, the die coater 10 according to the present invention significantly reduces the possibility of two different liquids being mixed therein.

[0061] In an exemplary embodiment, the second coater shim 320 has an insulating liquid supply hole 326 penetrating the second coater shim 320 (see FIGS. 6 and 8 ), rather than the insulating liquid flow groove 323 having a bottom surface. The insulating liquid supply hole 326 may be disposed within the closed end of the insulating liquid flow groove 323. That is, the insulating liquid supply hole 326 is disposed at the closed end of the insulating liquid flow groove 323, and the open end of the insulating liquid flow groove 323 forms the second slit 420. When the second coater shim 320 is coupled to the first block 200 and the second block 100, one end of the insulating liquid inlet pipe 110 of the second block 100 is connected to the insulating liquid supply hole 326 of the second coater shim 320. As a result, the insulating liquid supplied through the insulating liquid inlet pipe 110 flows through the insulating liquid supply hole 326 into the insulating liquid flow path groove 323 on the bottom surface of the second coater shim 320 facing the first block 200, and is then discharged to the outside through the open end of the insulating liquid flow path groove 323 that forms the second slit 420.

[0062] Referring to Figures 7 and 9(a) together, the length L1 of the first side wall 321, which is located relatively far from the first slit 410, is longer than the length L2 of the second side wall 322, which is located relatively close to the first slit 410, so the plane of the second slit 420 is not coplanar with the plane of the first slit, but is inclined.

[0063] Therefore, even if there is a difference in thickness between the electrode slurry layer and the insulating liquid layer applied to the first surface of the current collector F, when a back-coating process is performed using the die coater of the present invention to apply the electrode slurry and the insulating liquid to the second surface of the current collector F, as shown in FIG. 10, the distance G3 from the first side wall 321 forming the second slit 420 to the current collector F and the distance G2 from the second side wall 322 forming the second slit 420 to the current collector F are the same or similar, and it is possible to prevent the occurrence of fat edges in the insulating layer during the back-coating process.

[0064] 9 and 10, one end 321P in the first direction (Z direction) of the first side wall 321 of the second coater shim 320 may protrude outward from the tip ends of the first block 200 and the second block 100. As a result, while the coating gap in the conventional die coater 1 is determined by the tip ends of the first block and the second block, in the die coater 10 of the present invention, the coating gap at the portion where the insulating liquid is discharged is determined by the second coater shim.

[0065] Meanwhile, one end 322P of the second side wall 322 of the second coater shim 320 in the first direction (Z direction) may protrude outward from the tip end of the first block 200 and the second block 100, or may be located inside. Whether the second side wall 322 is located inside or outside the first block 200 and the second block 100 can be appropriately selected depending on the thickness of the insulating liquid to be applied. Specifically, if the insulating liquid must be applied thickly, it is preferable that one end 322P of the second side wall 322 be located inside the first block 200 and the second block 100. Conversely, if the insulating liquid must be applied thinly, it is preferable that one end 322P of the second side wall 322 be located outside the first block 200 and the second block 100.

[0066] The interior angle formed by an imaginary line connecting one end 321P of the first side wall 321 and one end 322P of the second side wall 322 and an imaginary line extending along the second direction (Y direction) may be the same as or similar to the interior angle formed by the current collector F and the coating roller CR, as shown in FIG. 10.

[0067] (Second embodiment) FIG. 13 is an exploded perspective view of a die coater according to an exemplary embodiment of the present invention.

[0068] FIG. 14 is a front view of the die coater of FIG.

[0069] Referring to these drawings, in an exemplary embodiment, the first coater shim 310 may further include a third guide 318 disposed between the first guide 314 and the second guide 316 with respect to the second direction (Y direction). Here, the first coater shim 310 forms first slits 410 in the spaces between the first guide 314 and the third guide 318 and between the third guide 318 and the second guide 316. That is, by adding the third guide 318, the number of first slits 410 increases, and electrode slurry can be applied in two rows.

[0070] Auxiliary shims 330 that form second slits 420 can be disposed on both sides of the third guide 318 in the second direction (Y direction). Fig. 13 shows an embodiment in which the second coater shim 320 of the present invention is used as the auxiliary shim, but the present invention is not limited to this. That is, the second coater shim 5 having the shape shown in Fig. 1 may also be used as the auxiliary shim.

[0071] When two rows of electrode slurry application portions are provided, the coating gap varies along the second direction at positions corresponding to the first guide 314 and the second guide 316 during back coating, but may vary or remain constant along the second direction at the position corresponding to the third guide 318. After top coating, a first electrode slurry application portion applied to one side of the third guide 318 in the second direction and a second electrode slurry application portion applied to the other side of the third guide 318 in the second direction are symmetrically arranged on the top coating surface of the electrode. The coating gap may be constant or variable depending on the separation distance in the second direction between the first and second electrode slurry application portions, the thicknesses of the first and second electrode slurry application portions, and the sliding gradient of the electrode slurry and insulating liquid. If the coating gap is constant, a conventional second coater shim can be used as the auxiliary shim. If the coating gap varies, the second coater shim of the present invention can be used as the auxiliary shim.

[0072] A method for coating an electrode according to an exemplary embodiment of the present invention will now be described.

[0073] An electrode coating method according to an exemplary embodiment of the present invention includes a top coating step of coating a first surface of a current collector with an electrode slurry and an insulating liquid, and a back coating step of coating a second surface of the current collector with an electrode slurry and an insulating liquid, and the back coating step is characterized in that the above-described coating equipment is used in the back coating step. The above-described die coater and coating equipment can be used only in the back coating step.

[0074] For example, the coating equipment includes a die coater 10 configured to simultaneously discharge electrode slurry and insulating liquid, and a coating roller CR configured to rotate to transport an electrode substrate, and the die coater 10 includes a first block 200 having a manifold that accommodates the electrode slurry, a second block 100 coupled to the first block 200, and a coater shim 300 interposed between the first block 200 and the second block 100. The coater shim 300 includes a first coater shim 310 that forms a first slit 410 through which the electrode slurry is discharged, and at least one second coater shim 320 that forms a second slit 420 through which the insulating liquid is discharged. The second coater shim 320 has a pair of first and second side walls extending along a first direction, which is the direction in which the insulating liquid is ejected, and is characterized in that, based on a second direction perpendicular to the first direction, the length L1 of the first side wall located on the outside is longer than the length L2 of the second side wall located on the inside.

[0075] In the die coater 10 according to the present invention, the second coater shim that forms the second slit 420 for discharging the insulating liquid has been redesigned as described above, taking into account the difference in thickness between the electrode slurry layer applied to the first surface (top coating surface) and the insulating liquid layer during the back coating process. As a result, when coating is performed using the coating equipment according to the present invention during the back coating process, the coating gap becomes constant along the direction (Y direction) from the electrode slurry layer toward the insulating liquid layer, preventing the occurrence of fat edges where the coating thickness becomes relatively thick in the insulating liquid layer.

[0076] The die coater 10 and the coating roller CR have been described in detail above, so a duplicated description will be omitted.

[0077] FIG. 12 is a schematic diagram illustrating a coating method according to an exemplary embodiment of the present invention.

[0078] Referring to FIG. 12 , a current collector F substrate is supplied through an unwinder UW. A top coating process is performed in which a first surface of the current collector F is coated with electrode slurry and an insulating liquid using a die coater 1. The top-coated current collector F is then dried through a first heating unit 40. The first heating unit 40 may include multiple drying zones 41, 42, and 43. The current collector F that has undergone the top coating and drying processes is then subjected to a back coating process. A second surface of the top-coated current collector F is coated with electrode slurry and an insulating liquid using a die coater 10. The back-coated current collector F then passes through a second heating unit 60. The second heating unit 60 may include multiple drying zones 61, 62, and 63. The electrode manufactured through the top coating and back coating processes is wound around a rewinder RW.

[0079] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations shown in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, and therefore, there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0080] 1, 10: Die coater 100: Second Block 110: Insulating liquid inlet pipe 120: Electrode slurry inlet 200: 1st Block 210: Manifold 300: Kotasim 310: First Kotasim 320: 2nd Kotasim 321: First side wall 322: Second side wall 323: Insulating liquid flow groove 410: First slit 420: Second slit

Claims

1. a first block having a manifold for containing an electrode slurry; a second block coupled to the first block; a coater shim interposed between the first block and the second block; Including, The said coatashim is a first coater shim forming a first slit for discharging the electrode slurry, and a second coater shim forming a second slit for discharging the insulating liquid, The second coater shim is a pair of first and second side walls extending along a first direction, which is a direction in which the insulating liquid is discharged; A die coater, wherein a length L1 of a first side wall located on the outside is longer than a length L2 of a second side wall located on the inside, based on a second direction perpendicular to the first direction.

2. The die coater according to claim 1 , wherein the plane of the second slit is inclined relative to the plane of the first slit.

3. The die coater according to claim 1 , wherein one end of the first side wall in the first direction protrudes outward from tip ends of the first block and the second block.

4. The die coater according to claim 1 , wherein one end of the second side wall in the first direction is located inward from tip ends of the first block and the second block.

5. The die coater according to claim 1 , wherein the width of the first slit is limited by the width of the second coater shim.

6. a height of the first slit corresponds to a height of the first coater shim; The die coater according to claim 5 , wherein the height of the second slit is smaller than the height of the second coater shim.

7. The die coater according to claim 1 , wherein one of the first block and the second block includes an insulating liquid inlet pipe for supplying an insulating liquid.

8. The die coater according to claim 1 , wherein the second coater shim is provided with a recessed insulating liquid flow channel having a bottom surface that is open toward the first block.

9. The die coater according to claim 8 , wherein the second coater shim is arranged so as not to overlap with the manifold of the first block.

10. 9. The die coater according to claim 8, wherein an insulating liquid supply hole is disposed at a closed end of the insulating liquid flow channel, and the open end of the insulating liquid flow channel forms the second slit.

11. The die coater according to claim 10 , wherein one end of an insulating liquid inlet pipe is connected to the insulating liquid supply hole.

12. The die coater according to claim 1 , wherein the second coater shim is fixedly coupled to at least one of the first block and the second block.

13. The first coater shim is a base extending along the second direction; a first guide and a second guide extending from opposite ends of the base, The die coater according to claim 1 , wherein the first guide and the second guide are spaced apart with the manifold therebetween.

14. The die coater according to claim 13 , wherein the first guide and the second guide are spaced apart from each other so as not to cover the manifold.

15. 15. The die coater according to claim 1, wherein there are two or more second coater shims, and the second coater shims are arranged so that the second slit is located at an edge of the first slit in the second direction.

16. a die coater configured to simultaneously discharge electrode slurry and insulating liquid; a coating roller configured to rotate to transport the electrode substrate; Including, The die coater is a first block having a manifold for containing an electrode slurry; a second block coupled to the first block; a coater shim interposed between the first block and the second block; Including, the coater shim includes a first coater shim forming a first slit for discharging the electrode slurry and a second coater shim forming a second slit for discharging the insulating liquid; The second coater shim is a pair of first and second side walls extending along a first direction, which is a direction in which the insulating liquid is discharged; The coating equipment, in which a length L1 of the first side wall located on the outer side is longer than a length L2 of the second side wall located on the inner side, based on a second direction perpendicular to the first direction.

17. a top coating step of coating a first surface of a current collector with an electrode slurry and an insulating liquid; a back-coating step of coating the second surface of the current collector with an electrode slurry and an insulating liquid, 17. A method for coating an electrode, wherein the back coating step uses the coating equipment according to claim 16.

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