Die coater, coating equipment comprising same, and method for coating electrode using same

Abstract

A die coater, according to the present invention, comprises a second coater shim that forms a second slit through which an insulating liquid is ejected, wherein length L1 of a first side wall positioned relatively farther from a first slit is longer than length L2 of a second side wall positioned relatively closer to the first slit.

Description

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

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

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

[0003] With technological advancements and growing demand for mobile devices, demand for secondary batteries is also rapidly increasing. Among these, lithium secondary batteries are widely used as a power source for various mobile devices and other electronic products due to their high energy density, high operating voltage, and excellent storage and lifespan characteristics.

[0004] Lithium secondary batteries utilize electrodes formed with active material layers and insulating layers on the surface of a current collector. These electrodes are manufactured by applying an electrode slurry containing an active material and an insulating solution containing an insulating material to the surface of a current collector using a coating device such as a die coater, such that some of the edges of the electrode active material layers overlap, and then drying the resulting mixture.

[0005] A double-sided electrode having a structure in which electrode active material layers are arranged on both sides of a current collector is manufactured through a top coating process in which electrode slurry and an insulating solution are coated on the first side, which is the front side of the current collector, and a back coating process in which electrode slurry and an insulating solution are coated on the second side, which is the back side of the current collector.

[0006] Fig. 1 is an exploded perspective view of a conventional die coater, Fig. 2 is a front view of a 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 a conventional die coater.

[0007] Referring to FIGS. 1 and 2, in a conventional die coater (1), the lengths of the first and second side walls (5a, 5b) extending parallel to the first direction (Z direction), which is the direction in which the insulating liquid is discharged, are the same in the second coater core (5) forming the second slit (7) through which the insulating liquid is discharged.

[0008] When a back coating process of coating electrode slurry and insulating liquid on the second surface, which is the back surface of the current collector, is performed using a conventional die coater (1), a PET-edge portion is generated in the insulating liquid layer (IL), as shown in Fig. 4.

[0009] The PET-edge portion can cause interference during cell assembly due to its protruding shape. Reducing the overall thickness of the insulating solution to address this issue can pose safety risks. Therefore, the development of coating equipment and methods that prevent PET-edge portions from forming in the insulating solution layer during the back-coating process of double-sided electrodes is necessary.

[0010] (Patent Document 1) Republic of Korea Patent Publication No. 10-2020-0049640

[0011] The technical idea of ​​the present invention is to provide a die coater that prevents the formation of a PET-edge portion in an insulating layer during a back coating process of a double-sided electrode, a coating facility including the die coater, and a coating method.

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

[0013] The above die coater,

[0014] A first block having a manifold for receiving electrode slurry;

[0015] a second block coupled to the first block; and

[0016] A cotter core interposed between the first block and the second block;

[0017] The above cotter plant,

[0018] A first coater core forming a first slit for discharging the electrode slurry; and

[0019] At least one second coater core forming a second slit for discharging an insulating liquid;

[0020] The above second coater core,

[0021] It has a pair of first and second side walls extending along the first direction, which is the discharge direction of the insulating liquid,

[0022] With respect to the 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.

[0023] In exemplary embodiments, the plane of the second slit is inclined with respect to the plane of the first slit.

[0024] In exemplary embodiments, the first end of the first side wall protrudes outward from the tip of the first and second blocks.

[0025] In exemplary embodiments, the first direction end of the second side wall is located inward from the tip end of the first and second blocks.

[0026] In exemplary embodiments, the width of the first slit is limited to the width of the second coater core.

[0027] In exemplary embodiments, the height of the first slit corresponds to the height of the first coater core, and the height of the second slit is less than the height of the second coater core.

[0028] In exemplary embodiments, one of the first block and the second block has an insulating liquid inlet pipe for supplying the insulating liquid.

[0029] In exemplary embodiments, the second coater core has a concave insulating liquid flow groove that is open toward the first block and has a bottom surface.

[0030] In exemplary embodiments, the second coater core is positioned so as not to overlap the manifold of the first block.

[0031] In exemplary embodiments, an insulating liquid supply hole is arranged at a closed end of the insulating liquid flow groove, and an open end of the insulating liquid flow groove forms the second slit.

[0032] In exemplary embodiments, one end of the insulating liquid inlet pipe is connected to the insulating liquid supply hole.

[0033] In exemplary embodiments, the second coater core is coupled and fixed to at least one of the first block and the second block.

[0034] In exemplary embodiments, the first coater core includes a base extending along the second direction, and a first guide and a second guide protruding and extending from each end of the base, wherein the first guide and the second guide are spaced apart from each other with the manifold interposed therebetween.

[0035] In exemplary embodiments, the first guide and the second guide are spaced apart from each other so as not to cover the manifold.

[0036] In exemplary embodiments, the second coater core is arranged such that two or more second coater cores are provided, and the second slits are positioned at the edge of the first slit in the second direction.

[0037] According to another embodiment of the present invention, a coating facility is provided. The coating facility includes a die coater configured to simultaneously discharge electrode slurry and an insulating liquid; and a coating roller configured to rotate to transport an electrode substrate;

[0038] The above die coater,

[0039] A first block having a manifold for receiving electrode slurry;

[0040] a second block coupled to the first block; and

[0041] including a cotter core interposed between the first block and the second block;

[0042] The above cotter plant,

[0043] It includes a first coater core forming a first slit for discharging the electrode slurry; and a second coater core forming a second slit for discharging an insulating liquid;

[0044] The above second coater core,

[0045] It has a pair of first and second side walls extending along the first direction, which is the discharge direction of the insulating liquid,

[0046] With respect to the 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.

[0047] According to another embodiment of the present invention, a method for coating an electrode is provided.

[0048] The coating method of the present invention includes a top coating process for coating an electrode slurry and an insulating liquid on a first surface of a current collector; a back coating process for coating an electrode slurry and an insulating liquid on a second surface of the current collector; and the back coating process uses the coating equipment described above.

[0049] According to exemplary embodiments of the present invention, when performing back coating, the coating gap, which is the distance between the tip of the second coater core forming the second slit through which the insulating liquid is discharged and the current collector which is the electrode substrate, becomes constant along the width direction, so that a PET-edge portion does not occur in the insulating liquid layer, and formation of an insulating layer with a uniform coating thickness is possible.

[0050] 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 those of ordinary skill in the art from the following description.

[0051] Figure 1 is an exploded perspective view of a conventional die coater.

[0052] Figure 2 is a front view of a conventional die coater.

[0053] Figure 3 is a drawing for explaining a problem when performing a back coating process using a conventional die coater.

[0054] Fig. 4 is a cross-sectional view of a portion of an electrode manufactured by performing a back coating process using a conventional die coater.

[0055] FIG. 5 is a drawing illustrating a back coating process performed using a coating facility according to an exemplary embodiment of the present invention.

[0056] Figure 6 is an exploded perspective view of a die coater according to an exemplary embodiment of the present invention.

[0057] Figure 7 is a front view of the die coater of Figure 6.

[0058] Figure 8 is a plan view of the die coater viewed through the first block of Figure 6.

[0059] Fig. 9 is an enlarged plan view and front view of part “A” of Fig. 8.

[0060] FIG. 10 is an enlarged view of the area around the second coater core in a coating facility according to an exemplary embodiment of the present invention.

[0061] Fig. 11 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.

[0062] Fig. 12 is a schematic diagram illustrating a coating method according to an exemplary embodiment of the present invention.

[0063] Figure 13 is an exploded perspective view of a die coater according to an exemplary embodiment of the present invention.

[0064] Fig. 14 is a front view of the die coater of Fig. 13.

[0065] [Explanation of symbols]

[0066] 1, 10: Die coater

[0067] 100: Block 2

[0068] 110: Insulating fluid inlet pipe

[0069] 120: Electrode slurry inlet

[0070] 200: Block 1

[0071] 210: Manifold

[0072] 300: Cotter core

[0073] 310: First coater core

[0074] 320: Second coater core

[0075] 321: First side wall

[0076] 322: Second side wall

[0077] 323: Insulating fluid Euro home

[0078] 410: First slit

[0079] 420: Second slit

[0080] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0081] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0082] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0083] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0084] As used herein, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0085] In this specification, the first direction is defined as the Z direction, which is the discharge direction of the electrode slurry or insulating liquid, and the second direction is defined as the Y direction, which is the width direction of the die coater and is perpendicular to the first direction.

[0086] The present invention relates to a die coater capable of simultaneously coating two different types of liquids on an electrode substrate of a secondary battery electrode, a coating facility including the same, and a coating method.

[0087] FIG. 3 is a drawing for explaining a problem when performing a back coating process using a die coater. The inventors of the present invention have found that the occurrence of a PET-edge portion is due to the difference in the thickness of the electrode slurry layer (ES) coated on the first surface of the current collector (F) after the top coating process and the thickness of the insulating liquid layer (IL). Referring to FIG. 3, the conventional die coater shows that the coating gap (G1, G2), which is the distance from the tip of the first and second blocks (2, 3) from which the insulating liquid is discharged during the back coating to the current collector (F), is not constant and varies along the second direction (Y direction). Specifically, the coating gap (G1, G2) gradually lengthens from the electrode slurry layer (ES) toward the insulating liquid layer (IL). When the back coating process is performed in this state, a PET-edge portion (FE) with a relatively thick coating thickness is generated on a portion of the insulating layer formed on the second surface of the current collector, as shown in Fig. 4.

[0088]

[0089] According to exemplary embodiments of the present invention, a die coater has a second coater shim that forms a second slit for discharging an insulating liquid, which is designed differently from the conventional technology, in order to prevent a PET-edge portion from occurring in the insulating liquid layer during the back coating process for manufacturing a double-sided electrode. The inventors of the present invention have noted that in a double-sided electrode, the PET-edge portion does 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 extensive research, they have found that the cause of the problem is due to the difference in the coating gap as described above, and in order to solve this problem, they have changed the design of the second coater shim so that the coating gap is constant during back coating. That is, the design of the die coater has been changed so as to compensate for the difference in the thickness of the electrode slurry layer applied to the first side and the thickness of the insulating liquid layer.

[0090]

[0091] (Example 1)

[0092] FIG. 5 is a drawing showing a back coating process performed using a coating equipment according to an exemplary embodiment of the present invention, FIG. 6 is an exploded perspective view of a die coater according to an exemplary embodiment of the present invention, FIG. 7 is a front view of the die coater of FIG. 6, FIG. 8 is a plan view of the die coater viewed through the first block of FIG. 6, FIG. 9 is a plan view and a front view enlarged of a portion “A” of FIG. 8, and FIG. 10 is an enlarged view of the area around a second coater core in a coating equipment according to an exemplary embodiment of the present invention.

[0093] Referring to FIG. 5, a coating facility according to an exemplary embodiment of the present invention includes a die coater (10) and a coating roller (20).

[0094] The die coater (10) is configured to simultaneously discharge electrode slurry (ES) and insulating liquid (not shown) onto a current collector (F), which is an electrode substrate, and the coating roller (20) is configured to rotate to transport the electrode substrate in one direction.

[0095] Referring to FIGS. 6 to 8, a die coater (10) according to exemplary embodiments includes a first block (200) having a manifold (210) for receiving 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).

[0096] Here, the coater shim (300) of the present invention includes a first coater shim (310) and a second coater shim (320). In the above drawings, an embodiment in which the second coater shim (320) is configured to be coupled and detachable from the first coater shim (310) is shown, but 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 form 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 form a second slit (420) for discharging insulating liquid supplied through the insulating liquid inlet pipe (110). The second coater core (320) is positioned so that the second slit (420) is positioned at the edge of the first slit (410) in the second direction (Y direction). Accordingly, the insulating liquid can be applied to the edge of the electrode slurry application portion in the second direction. The number of second coater cores (320) is determined according to the number of insulating liquid application rows, and may be, for example, one or two or more.

[0097] In particular, in order to prevent the occurrence of a PET-edge portion in the insulating layer, the die coater (10) of the present invention has a second coater core (320) designed differently from the prior art so that the coating gap, which is the distance between the tip of the second coater core (320) forming the second slit (420) and the electrode substrate during the back coating process, is constant along the second direction (Y direction), which is the width direction of the die coater.

[0098] Referring to FIGS. 7 to 9, the second coater core (320) has a pair of first and second side walls (321, 322) extending along the first direction (Z direction), which is the discharge direction of the insulating liquid. In the second coater core (320), the first side wall (321) is located on the outer side, and the second side wall (322) is located on the inner side, with respect to the second direction (Y direction). The length L1 of the first side wall (321) is greater than the length L2 of the second side wall (322).

[0099] Accordingly, as illustrated in FIG. 10, even if there is a difference between the thickness of the electrode slurry layer (ES) coated on the first surface of the current collector (F) and the thickness of the insulating liquid layer (IL), the coating gap, which is the distance between the tip of the second coater core (320) forming the second slit (420) through which the insulating liquid is discharged and 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, as illustrated in FIG. 11, a PET-edge portion does not occur in the insulating liquid layer (IL) applied on both surfaces.

[0100]

[0101] In exemplary embodiments, the first block (200) may be provided with a manifold (210) for receiving electrode slurry. The second block (100) coupled to the first block (200) may be provided with 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 body of the die coater (10).

[0102] For reference, in FIG. 6, an electrode slurry inlet (120) communicating with a manifold (210) of a first block (200) is illustrated as being formed in a second block (100), but the electrode slurry inlet (120) may be formed in the first block (200). In addition, in FIG. 6, an insulating liquid inlet pipe (110) for supplying an insulating liquid is illustrated as being formed in a second block (100), but the insulating liquid inlet pipe (110) may be formed in the first block (200).

[0103] The coater core (300; 310, 320) is interposed between the first block (200) and the second block (100) to form a slit of a height suitable for discharging electrode slurry and insulating liquid. The coater core (300; 310, 320) restricts the flow direction of the liquids flowing into or received in the die coater (10) so that they are discharged toward the slit without flowing back, and also serves to seal the liquids so that they do not leak to other parts than the slit.

[0104] The present invention is a coater shim, which includes a first coater shim (310) and a second coater shim (320), wherein 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 a first slit (410) for discharging electrode slurry contained in a manifold (210) of a first block (200), and the second coater shim (320) forms a second slit (420) for discharging insulating liquid supplied through an insulating liquid inlet pipe (110) of a second block (100).

[0105] And, the first cotter core (310) and the second cotter core (320) have the same height and do not overlap vertically. Therefore, the first cotter core (310) and the second cotter core (320) are placed on the same plane between the first block (200) and the second block (100). And, the first cotter core (310) and the second cotter core (320) are respectively coupled and fixed to at least one of the first and second blocks (200, 100). Therefore, the upper and lower surfaces of the first cotter core (310) and the second cotter core (320) are sealed by being in close contact with the first block (200) and the second block (100) respectively by a pressing force applied by the fastening of the first block (200) and the second block (100), for example, bolt fastening (not shown in the drawing).

[0106] The first coater shim (310) includes a base (312) extending along the second direction (Y direction), and a first guide (314) and a second guide (316) protrudingly extending from both ends of the base (312), respectively. Here, the first coater shim (310) forms a space between the first and second guides (314, 316) as a first slit (410). The first guide (314) and the second guide (316) are spaced apart from each other with the manifold (210) interposed therebetween, and are positioned so as not to cover the manifold (210). Accordingly, 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) and the first and second blocks (200, 100).

[0107] In exemplary embodiments, the second coater shim (320) is open toward the first block (200) and has an insulating liquid flow path groove (323) in the form of a concave groove having a bottom surface (see (b) of FIG. 9). The second coater shim (320) has an open end of the insulating liquid flow path groove (323) in the form of a groove that forms a second slit (420). Since the depth of the insulating liquid flow path groove (323) is smaller than the thickness (height) of the second coater shim (320), as shown in FIG. 7, 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 formed to be smaller than the height of the second coater shim (320). Here, the 'height' is the length in the X direction. And, since the second coater core (320) has the insulating fluid flow groove (323) facing the first block (200), the second slit (420) is defined as a space formed between the insulating fluid flow groove (323) and the first block (200).

[0108] Since the first coater core (310) and the second coater core (320) have the same height and are not overlapped vertically but are placed on the same plane, the width of the first slit (410) is limited to the width of the second coater core (320).

[0109] In exemplary embodiments, the first side wall (321) of the second coater shim (320) may be in close contact with the inner side wall of the first guide (314) or the second guide (316), respectively. Accordingly, the distance between the opposing second side walls (322) (opposite sides of the first side walls) of the pair of second coater shims (320) corresponds to the actual width of the first slit (410). That 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) becomes the width of the first slit (410).

[0110] In exemplary embodiments, the second coater shim (320) may be positioned so as not to overlap with the manifold (210) of the first block (200). Accordingly, looking at the structure of the second slit (420) formed by the second coater shim (320), the electrode slurry of the first slit (410) is blocked by both side walls (321, 322) of the second coater shim (320), and the upper side of the insulating liquid flow path groove (323) is the bottom surface, while the lower side is in close contact with the plane of the first block (200), so that 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 that two different types of liquids will be mixed inside it.

[0111] In exemplary embodiments, the second coater shim (320) has an insulating liquid supply hole (326) formed therein, which penetrates the second coater shim (320), unlike the insulating liquid flow groove (323) having a bottom surface (see FIGS. 6 and 8), and the insulating liquid supply hole (326) may be disposed within a 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 a second slit (420). In addition, when the second coater shim (320) is connected to the first and second blocks (200, 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). Accordingly, the insulating liquid supplied through the insulating liquid inlet pipe (110) flows through the insulating liquid supply hole (326) to the insulating liquid flow groove (323) on the bottom surface of the second coater core (320) facing the first block (200), and is then discharged to the outside through the open end of the insulating liquid flow groove (323) forming the second slit (420).

[0112] Referring to (a) of FIG. 7 and FIG. 9 together, since the length L1 of the first side wall (321) located relatively far from the first slit (410) is longer than the length L2 of the second side wall (322) located relatively close to the first slit (410), the plane of the second slit (420) is not located on the same plane as the plane of the first slit, but is inclined.

[0113] Therefore, even if there is a difference in the thickness of the electrode slurry layer applied to the first surface of the current collector (F) and the thickness of the insulating liquid layer, when a back coating process of applying the electrode slurry and the insulating liquid to the second surface of the current collector (F) using the die coater of the present invention is performed, 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 levels, so that the occurrence of a PET-edge portion in the insulating layer during the back coating process can be prevented.

[0114] Referring to FIGS. 9 and 10, the first direction (Z direction) end (321P) of the first side wall (321) of the second coater core (320) may protrude outward from the leading ends of the first and second blocks (200, 100). Accordingly, while the coating gap of the conventional die coater (1) is determined by the leading ends of the first and second blocks, the coating gap of the portion where the insulating liquid is discharged in the die coater (10) of the present invention is determined by the second coater core.

[0115] Meanwhile, the second side wall (322) of the second coater core (320) may have one end (322P) in the first direction (Z direction) protruding outward from the tip of the first and second blocks (200, 100) or may be positioned on the inside. The position of the second side wall (322) between the inside and the outside of the first and second blocks (200, 100) may be appropriately selected depending on the thickness of the insulating solution applied. Specifically, when the thickness of the insulating solution applied must be thick, it is preferable that one end (322P) of the second side wall (322) be positioned on the inside of the first and second blocks (200, 100), and conversely, when the thickness of the insulating solution applied is thin, it is preferable that one end (322P) of the second side wall (322) be positioned on the outside of the first and second blocks (200, 100).

[0116] The angle of the internal angle formed by the imaginary line connecting one end (321P) of the first side wall (321) and one end (322P) of the second side wall (322) and the imaginary line extending along the second direction (Y direction) may be the same as or similar to the angle of the internal angle formed by the current collector (F) and the coating roller (CR), as illustrated in FIG. 10.

[0117]

[0118] (Example 2)

[0119] Figure 13 is an exploded perspective view of a die coater according to an exemplary embodiment of the present invention.

[0120] Fig. 14 is a front view of the die coater of Fig. 13.

[0121] Referring to these drawings, in exemplary embodiments, the first coater core (310) may further include a third guide (318) positioned between the first guide (314) and the second guide (316) in the second direction (Y direction). Here, the first coater core (310) forms a space between the first guide (314) and the third guide (318) and a space between the third guide (318) and the second guide (316) as a first slit (410), respectively. That is, as the third guide (318) is added, the number of first slits (410) increases, and the electrode slurry can be applied in two rows.

[0122] Auxiliary shims (330) forming second slits (420) may be arranged on both sides of the second direction (Y direction) of the third guide (318). Fig. 13 illustrates an embodiment in which the second coater shim (320) of the present invention is employed as the auxiliary shim, but the present invention is not limited thereto. That is, the second coater shim (5) having the shape illustrated in Fig. 1 may also be employed as the auxiliary shim.

[0123] When the electrode slurry application portion is in two rows, the coating gap changes along the second direction at positions corresponding to the first and second guides (314, 316) during back coating, but the coating gap may change along the second direction or may be constant at positions corresponding to the third guide (318). After the top coating, the first electrode slurry application portion applied to one side of the third guide (318) in the second direction and the 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 constant depending on the second direction separation distance between the first electrode slurry application portion and the second electrode slurry application portion, the thickness of the first electrode slurry application portion and the thickness of the second electrode slurry application portion, and the sliding inclination of the electrode slurry and the insulating liquid. If the coating gap is constant, a conventional second coater core can be used as an auxiliary core, and if the coating gap changes, the second coater core of the present invention can be used as an auxiliary core.

[0124]

[0125] Hereinafter, a coating method of an electrode according to exemplary embodiments of the present invention will be described.

[0126] A coating method of an electrode according to exemplary embodiments of the present invention includes a top coating process for coating an electrode slurry and an insulating solution on a first surface of a current collector; a back coating process for coating an electrode slurry and an insulating solution on a second surface of the current collector; and the back coating process is characterized in that it uses the coating equipment described above. The die coater and coating equipment described above can be used only in the back coating process.

[0127] For example, the coating equipment includes a die coater (10) configured to simultaneously discharge electrode slurry and an 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 for receiving electrode slurry and a second block (100) coupled to the first block; and a coater core (300) interposed between the first block and the second block.

[0128] The above cotter core (300) is

[0129] It comprises a first coater core (310) forming a first slit (410) for discharging electrode slurry; and at least one second coater core (320) forming a second slit (420) for discharging insulating liquid;

[0130] The above second coater core (320) is

[0131] It is characterized in that it has a pair of first and second side walls extending along a first direction, which is a discharge direction of an insulating liquid, and a length L1 of the first side wall located on the outside with respect to a second direction perpendicular to the first direction is longer than a length L2 of the second side wall located on the inside.

[0132] The die coater (10) according to the present invention has a second coater shim designed as described above to form a second slit (420) for discharging the insulating liquid, 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. Accordingly, 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, thereby preventing the occurrence of a pet-edge portion in which the coating thickness is relatively thicker in the insulating liquid layer.

[0133] Since the die coater (10) and coating roller (CR) have been described in detail above, redundant descriptions are omitted.

[0134] Fig. 12 is a schematic diagram illustrating a coating method according to an exemplary embodiment of the present invention.

[0135] Referring to Fig. 12, a current collector (F) substrate is supplied through an unwinder (UW). A top coating process is performed to coat electrode slurry and an insulating solution on a first surface of the current collector (F) using a die coater (1). Then, the top-coated current collector (F) is dried through a first heating unit (40). The first heating unit (40) may include a plurality of drying zones (41, 42, 43). The current collector (F) that has undergone the top coating and drying processes undergoes a back coating process. The electrode slurry and an insulating solution are coated on a second surface of the top-coated current collector (F) using a die coater (10). Then, the back-coated current collector (F) passes through a second heating unit (60). The second heating unit (60) may include a plurality of drying zones (61, 62, 63). The electrode manufactured through the top coating and back coating processes is wound on a rewinder (RW).

[0136]

[0137] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

Claims

1. A first block having a manifold for receiving electrode slurry; a second block coupled to the first block; and A cotter core interposed between the first and second blocks Including, The above mentioned cotter plant, A first coater core forming a first slit for discharging the electrode slurry; and a second coater core forming a second slit for discharging an insulating liquid, The above second coater core, It has a pair of first and second side walls extending along the first direction, which is the discharge direction of the insulating liquid, A die coater, characterized in that, with respect to a second direction perpendicular to the first direction, a length L1 of a first side wall located on the outer side is longer than a length L2 of a second side wall located on the inner side.

2. In paragraph 1, A die coater, characterized in that the plane of the second slit is inclined with respect to the plane of the first slit.

3. In paragraph 1, A die coater, characterized in that one end of the first side wall in the first direction protrudes outward from the tip portions of the first and second blocks.

4. In paragraph 1, A die coater, characterized in that the first end of the second side wall is located inward from the leading ends of the first and second blocks.

5. In paragraph 1, A die coater, characterized in that the width of the first slit is limited to the width of the second coater core.

6. In paragraph 5, The height of the first slit corresponds to the height of the first coater core, A die coater, characterized in that the height of the second slit is smaller than the height of the second coater core.

7. In paragraph 1, A die coater, characterized in that one of the first block and the second block has an insulating liquid inlet pipe for supplying insulating liquid.

8. In paragraph 1, The above second coater core, A die coater, characterized by having a concave insulating liquid path groove that is open toward the first block and has a bottom surface.

9. In paragraph 8, The above second coater core, A die coater, characterized in that it is arranged so as not to overlap with the manifold of the first block.

10. In paragraph 8, A die coater, characterized in that an insulating liquid supply hole is arranged at a closed end of the insulating liquid flow groove, and an open end of the insulating liquid flow groove forms the second slit.

11. In paragraph 10, A die coater, characterized in that one end of the insulating liquid inlet pipe is connected to the insulating liquid supply hole.

12. In paragraph 1, A die coater, characterized in that the second coater core is fixedly joined to at least one of the first block and the second block.

13. In paragraph 1, The above first coater core, A base extending along the second direction, It includes first and second guides that are respectively extended and protruded from both ends of the above base, A die coater, characterized in that the first guide and the second guide are spaced apart with the manifold interposed therebetween.

14. In paragraph 13, A die coater, characterized in that the first guide and the second guide are spaced apart from each other so as not to cover the manifold.

15. In paragraph 1, A die coater, wherein the second coater core is arranged such that the second slit is located at the edge of the second direction of the first slit, and the second coater core is two or more.

16. A die coater configured to discharge electrode slurry and insulating liquid simultaneously; and A coating roller configured to rotate to transport an electrode substrate; The above die coater, A first block having a manifold for receiving electrode slurry; a second block coupled to the first block; and A cotter core interposed between the first block and the second block; Including, The above mentioned cotter plant, It comprises a first coater core forming a first slit for discharging the electrode slurry; and a second coater core forming a second slit for discharging an insulating liquid; The above second coater core, It has a pair of first and second side walls extending along the first direction, which is the discharge direction of the insulating liquid, With respect to the 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. Coating equipment.

17. Top coating process of coating the first surface of the collector with electrode slurry and insulating liquid; A back coating process for coating the second surface of the entire body with electrode slurry and insulating liquid; The above white coating process is a coating method for an electrode, characterized in that it uses a coating facility according to claim 16.

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