Spacing gasket, slot die coater and coating method using slot die coater
By optimizing the flow path structure of the spacer, the coating quality of the slot mold coating machine is improved, the problems of uneven coating and foreign matter entering are solved, and a more stable coating effect is achieved.
Patent Information
- Application Number
- CN202380085589.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-23
- Filing Date
- 2023-12-22
- Publication Date
- 2025-07-22
AI Technical Summary
The flow path design of the existing slot mold coating machine has not been optimized, resulting in deterioration of coating quality, and foreign matter is prone to entering the slot mold coating machine during cleaning, affecting the coating effect.
An improved spacer gasket is designed, including a flow path structure recessed on the gasket body, with inflow trenches, discharge trenches, bending trenches and connection trenches. By optimizing the flow path width and depth design, it ensures that the coating solution is evenly distributed, and a bridge trenches are provided at the intersection to equalize the flow path pressure and prevent foreign matter from entering.
The coating quality, especially the uniformity of the coating width, is improved, and foreign matters are prevented from entering the slot mold coating machine during cleaning, improving the stability of the coating effect.
Smart Images
Figure CN120359091A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a spacer, a slot die coater, and a coating method using the slot die coater, and more particularly, to a spacer having an improved flow path structure to improve coating quality, a slot die coater including the spacer, and a coating method using the slot die coater.
[0002] This application claims priority to Korean Patent Application No. 10-2022-0183772, filed in Korea on December 23, 2022, the disclosure of which is incorporated herein by reference. Background Art
[0003] Slot die coaters are widely used to coat active materials or insulating materials on battery electrode plates. A slot die coater includes a spacer interposed between two slot die blocks.
[0004] The spacer forms a flow path in the slot die coater. The flow path includes: an inflow path through which a coating solution is introduced from the outside; a discharge path through which the coating solution is ejected to the outside; and a connection path through which the inflow path and the discharge path communicate with each other.
[0005] The design of the spacer flow path structure affects the coating quality. If the design of the flow path is not optimized, the coating quality deteriorates, and foreign substances may also penetrate deep into the slot die coater during the process of cleaning the lip of the slot die coater. Summary of the Invention
[0006] Technical Problem
[0007] The present disclosure aims to solve the problems of the prior art, and thus the present disclosure aims to provide a spacer having an improved flow path structure to improve coating quality.
[0008] The present disclosure also relates to providing a slot die coater including an improved spacer.
[0009] The present disclosure also relates to providing a coating method using a slot die coater including an improved spacer.
[0010] Technical Solution
[0011] In one aspect of the present disclosure, there is provided a spacer including: a plate-shaped spacer body having a predetermined width, length, and thickness; and a flow path having a groove recessed in a thickness direction on one surface of the spacer body.
[0012] The flow path may include: an inflow groove into which the coating solution is introduced in the thickness direction; a first discharge groove and a second discharge groove, the first discharge groove and the second discharge groove being arranged to be spaced apart in the width direction to independently discharge the coating solution in the length direction; a first bending groove and a second bending groove, the first bending groove and the second bending groove being configured to branch from one side and the other side of the inflow groove respectively and extend in the width direction and the length direction; and a first connection groove and a second connection groove, the first connection groove and the second connection groove being configured to extend in the length direction from the first bending groove and the second bending groove respectively and communicate with the first discharge groove and the second discharge groove.
[0013] The first discharge groove and the first connection groove may be spaced apart from each other in the width direction and not overlap with each other in the length direction, and the second discharge groove and the second connection groove may be spaced apart from each other in the width direction and not overlap with each other in the length direction.
[0014] When the average flow path width of the first bending groove and the average flow path width of the second bending groove are defined as a first flow path width, the average flow path width of the first connection groove and the average flow path width of the second connection groove are defined as a second flow path width, and the average flow path width of the first discharge groove and the average flow path width of the second discharge groove are defined as a third flow path width, the first flow path width may be greater than the second flow path width, and the second flow path width may be greater than the third flow path width.
[0015] When the maximum separation distance in the width direction between the first bending groove and the second bending groove is defined as a first separation distance, the maximum separation distance in the width direction between the first connection groove and the second connection groove is defined as a second separation distance, and the maximum separation distance in the width direction between the first discharge groove and the second discharge groove is defined as a third separation distance, the first separation distance may be less than the second separation distance, and the second separation distance may be less than the third separation distance.
[0016] The flow path may further include a bridging groove, one end of the bridging groove may be inserted between the first discharge groove and the first connection groove, and the other end of the bridging groove may be inserted between the second discharge groove and the second connection groove.
[0017] The flow path width of the bridging groove may be greater than the flow path widths of the first discharge groove and the second discharge groove.
[0018] The depth of the bridging groove may be substantially the same as the depth of the first discharge groove and the depth of the second discharge groove.
[0019] The flow path may further include a bridging groove, one end of the bridging groove may communicate with the first connection groove, and the other end of the bridging groove may communicate with the second connection groove.
[0020] The flow path width of the bridging groove may be smaller than the flow path width of the first connection groove and smaller than the flow path width of the second connection groove.
[0021] The bridging groove may communicate with the first connection groove and the second connection groove at the same depth.
[0022] The bridging groove may intersect the first discharge groove and the second discharge groove substantially perpendicularly, and the flow path width of the intersection portion may gradually decrease toward the discharge groove.
[0023] The flow path of the intersection portion may have a structure in which an inner right angle and an outer rounded corner face each other.
[0024] The first connection groove and the second connection groove may each include a first section having a first average depth, a second section having a second average depth, and a third section having a third average depth along the length direction of the spacer body. The first average depth may be greater than the second average depth, and the second average depth may be greater than the third average depth.
[0025] The first section and the third section may have substantially the same groove depth along the flow direction of the coating solution, and the second section may have a groove depth that gradually decreases along the flow direction of the coating solution.
[0026] The groove depth of the third section may be substantially the same as the depth of the first discharge groove and the second discharge groove.
[0027] When observed in a cross-section perpendicular to the flow direction of the coating solution, the grooves forming the flow path may have a rounded bottom.
[0028] The spacer according to the present disclosure may have at least one fastening hole that passes through the spacer body but does not overlap with the flow path.
[0029] The spacer according to the present disclosure may include a coating layer formed on the exposed surface of the flow path in the thickness direction of the spacer body.
[0030] The coating layer may contain polytetrafluoroethylene.
[0031] In another aspect according to the present disclosure, there is also provided a slot die coater, including: at least one of the above-mentioned spacer gaskets; a first slot die block, the first slot die block being coupled to one side of the gasket body to face an exposed surface of the flow path in the thickness direction of the gasket body; a second slot die block, the second slot die block being coupled to the other side of the gasket body to face the first slot die block; and a coating solution supply unit configured to communicate with the inflow groove of the spacer gasket.
[0032] The slot die coater according to the present disclosure may include at least one pump configured to independently supply a coating solution via a coating solution supply unit communicating with the inflow groove of each spacer gasket.
[0033] In another aspect according to the present disclosure, there is also provided a coating method, including: preparing a substrate having a pair of short sides and a pair of long sides extending between the pair of short sides; forming a plurality of first coating layers at a predetermined interval in a long side direction on one surface of the substrate such that a strip-shaped uncoated portion extending in the long side direction is formed between the first coating layers adjacent in the short side direction; preparing the above-mentioned slot die coater; and using the slot die coater to form a second coating layer in the long side direction to cover a predetermined width of a boundary between each first coating layer and an uncoated portion adjacent thereto.
[0034] A pair of the second coating layers may be formed simultaneously at a boundary between the uncoated portion and a pair of the first coating layers facing the uncoated portion.
[0035] In the coating method according to the present disclosure, the substrate may be a metal foil current collector, the first coating layer may be an active material coating layer, and the second coating layer may be an insulating coating layer.
[0036] Advantageous Effects
[0037] According to one aspect of the present disclosure, the coating quality can be improved, especially the uniformity of the coating width, by improving the flow path structure of the spacer gasket.
[0038] According to another aspect of the present disclosure, foreign matter can be prevented from entering the slot die coater during the process of cleaning the lip of the slot die coater.
[0039] According to still another aspect of the present disclosure, when a second coating layer is formed at a boundary between each first coating layer and an uncoated portion while transporting a substrate (on which a plurality of strip-shaped first coating layers are formed at regular intervals and uncoated portions are inserted between the first coating layers), the width of the second coating layer can be kept uniform in a direction perpendicular to the transport direction. Description of the Drawings
[0040] The accompanying drawings illustrate preferred embodiments of the present disclosure and, together with the foregoing disclosure, are used to provide a further understanding of the technical features of the present disclosure. Therefore, the present disclosure is not to be construed as being limited to the accompanying drawings.
[0041] Figure 1 is a plan view showing a spacer according to an embodiment of the present disclosure.
[0042] Figure 2 is along Figure 1 a cross-sectional view taken along line A-A' in
[0043] Figure 3 is along Figure 1 a cross-sectional view taken along line B-B' in
[0044] Figure 4 is a partial enlarged view showing the dotted circle portion on the right side of Figure 1
[0045] Figure 5 is a plan view showing the structure of a spacer according to another embodiment of the present disclosure.
[0046] Figure 6 is a cross-sectional view showing the configuration of a slot die coater according to an embodiment of the present disclosure.
[0047] Figure 7 is a plan view showing a slot die coater according to an embodiment of the present disclosure.
[0048] Figure 8 is a process diagram conceptually showing a coating method according to an embodiment of the present disclosure.
[0049] Figure 9 is a photograph of a current collector immediately after forming a positive electrode active material layer and an insulating coating layer on one surface of a current collector made of aluminum foil using a slot die coater including a spacer according to a comparative example of the present disclosure.
[0050] Figure 10 is a photograph of a current collector immediately after forming a positive electrode active material layer and an insulating coating layer on a current collector made of aluminum foil using a slot die coater including a spacer according to an embodiment of the present disclosure.
[0051] Figure 11 is a graph showing the results of measuring the average thickness of the insulating coating layer of each uncoated portion line when forming 6 pairs of insulating coating layers in a total of 6 uncoated portion lines using a slot die coater in a comparative example and an embodiment of the present disclosure after coating 7 rows of positive electrode active material layers with a width of 125.5 mm at intervals of 10 mm on one surface of an aluminum current collector. Detailed Description
[0052] In the following, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Before the description, it should be understood that the terms used in the specification and the appended claims should not be construed as limited to the general and dictionary meanings, but should be interpreted based on the principle that allows the inventor to appropriately define the terms for the best explanation, based on the meanings and concepts corresponding to the technical aspects of the present disclosure. Therefore, the description presented herein is only a preferred embodiment for illustrative purposes and is not intended to limit the scope of the present disclosure. Thus, it should be understood that other equivalent and modifications can be made without departing from the scope of the present disclosure.
[0053] Although terms such as first, second, etc. are used to describe different elements, these elements are not limited by these terms. These terms are used to distinguish one element from another. Unless otherwise stated, the first element can be the second element.
[0054] Throughout the specification, unless otherwise stated, each element can be singular or plural.
[0055] In the following, when an element is "above (or below) another element" or "on (or under) another element", the element can be on the upper surface (or lower surface) of the other element, and there can be an intermediate element between the element and the other element above (or below) it.
[0056] In addition, when an element is referred to as being "connected", "coupled", or "linked" to another element, the element can be directly connected or coupled to the other element. However, it should be understood that there can be an intermediate element between each element, or each element can be "connected", "coupled", or "linked" to each other by means of another element.
[0057] The singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "including" or "comprising" should not be construed as necessarily including all the individual components or steps described in the specification, but should be interpreted as being able to exclude some components or some steps, or being able to further include additional components or steps.
[0058] Furthermore, the singular expressions used in this specification include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "including" or "comprising" should not be construed as necessarily including all the individual components or steps described in the specification, but should be interpreted as being able to exclude some components or some steps, or being able to further include additional components or steps.
[0059] Throughout the specification, unless otherwise explicitly stated, "A and / or B" means A or B or both A and B, and unless otherwise explicitly stated, "C to D" means above C and below D.
[0060] Figure 1 is a plan view showing a spacer according to an embodiment of the present disclosure, Figure 2 is along Figure 1 a cross-sectional view taken along line A-A' in Figure 3 is along Figure 1 a cross-sectional view taken along line B-B' in, and Figure 4 is a partial enlarged view showing Figure 1 the dashed circle portion on the right side.
[0061] Referring to Figures 1 to 4 , the spacer 10 according to an embodiment of the present disclosure may include a plate-shaped spacer body 11 having a predetermined width, length, and thickness, and a flow path 12 formed by a groove recessed from one surface of the spacer body 11 in the thickness direction.
[0062] In the drawings, for ease of explanation, a three-dimensional coordinate system is shown. The X-axis is the width direction of the spacer body 11, the Y-axis is the length direction of the spacer body 11, and the Z-axis is the thickness direction of the spacer body 11.
[0063] In Figure 1 , the shading of the flow path 12 represents the depth difference in the thickness direction Z. The darker the shading, the deeper the depth in the thickness direction Z. Additionally, in regions with the same shading, the depth in the thickness direction Z may be substantially the same. The depth of the flow path 12 may be the maximum depth at the measurement position.
[0064] The flow path 12 may have a left-right symmetric structure based on the length direction Y. The flow path 12 may have a groove structure recessed from one surface of the spacer body 11 in the thickness direction Z. The groove may be a kind of slot.
[0065] The flow path 12 may include: an inflow groove 12a into which the coating solution is introduced in the thickness direction Z; a first discharge groove 12b1 and a second discharge groove 12b2, the first discharge groove 12b1 and the second discharge groove 12b2 being arranged to be spaced apart in the width direction X and configured to independently discharge the coating solution in the length direction Y; a first bending groove 12c1 and a second bending groove 12c2, the first bending groove 12c1 and the second bending groove 12c2 branching from one side and the other side of the inflow groove 12a respectively and configured to extend in the width direction X and the length direction Y; and a first connection groove 12d1 and a second connection groove 12d2, the first connection groove 12d1 and the second connection groove 12d2 being configured to extend from the first bending groove 12c1 and the second bending groove 12c2 respectively in the length direction Y and directly or indirectly connected to the first discharge groove 12b1 and the second discharge groove 12b2.
[0066] When the average flow path width of the first bending groove 12c1 and the average flow path width of the second bending groove 12c2 are defined as the first flow path width, the average flow path width of the first connection groove 12d1 and the average flow path width of the second connection groove 12d2 are defined as the second flow path width, and the average flow path width of the first discharge groove 12b1 and the average flow path width of the second discharge groove 12b2 are defined as the third flow path width, the first flow path width may be greater than the second flow path width, and the second flow path width may be greater than the third flow path width.
[0067] The average flow path width refers to the average value of the lengths of the line segments located in the groove when line segments are drawn in a plane identical to the surface of the gasket body 11 perpendicular to the direction in which the coating solution flows at multiple points in the groove section. For example, multiple points may be selected every 0.5 mm. In the drawings, W1, W2, and W3 show the lengths of the line segments drawn at specific points in each groove section.
[0068] In a specific embodiment, the first flow path width may be 4 mm ± 0.5 mm, the second flow path width may be 2 mm ± 0.5 mm, and the third flow path width may be 1.3 mm ± 0.5 mm.
[0069] When the maximum separation distance d1 in the width direction of the first bending groove 12c1 and the second bending groove 12c2 is defined as the first separation distance, the maximum separation distance d2 in the width direction of the first connection groove 12d1 and the second connection groove 12d2 is defined as the second separation distance, and the maximum separation distance d3 in the width direction of the first discharge groove 12b1 and the second discharge groove 12b2 is defined as the third separation distance, the first separation distance d1 may be less than the second separation distance d2, and the second separation distance d2 may be less than the third separation distance d3.
[0070] In a specific embodiment, the first separation distance may be 10 mm ± 2 mm, the second separation distance may be 14 mm ± 1.5 mm, and the third separation distance may be 17 mm ± 1.0 mm.
[0071] The flow path 12 may further include a bridging groove 12e.
[0072] One end of the bridging groove 12e in the width direction X may be inserted between the first discharge groove 12b1 and the first connection groove 12d1. In addition, the other end of the bridging groove 12e in the width direction X may be inserted between the second discharge groove 12b2 and the second connection groove 12d2.
[0073] Therefore, the first discharge groove 12b1 and the first connection groove 12d1 may be indirectly connected to each other by one end of the bridging groove 12e. In addition, the second discharge groove 12b2 and the second connection groove 12d2 may be indirectly connected to each other by the other end of the bridging groove 12e.
[0074] The depth of the bridging groove 12e may be substantially the same as the depth of the first discharge groove 12b1 and the depth of the second discharge groove 12b2.
[0075] The flow path width of the bridging groove 12e may be relatively larger than the flow path width of the first discharge groove 12b1 and the flow path width of the second discharge groove 12b2.
[0076] The flow path width of the bridging groove 12e may be relatively smaller than the flow path width of the first connection groove 12d1 and the flow path width of the second connection groove 12d2.
[0077] The above design of the flow path width and depth of the bridging groove 12e can improve the coating quality by substantially equally increasing the flow path pressure of the first discharge groove 12b1 and the second discharge groove 12b2.
[0078] The bridging groove 12e may be substantially perpendicular to and cross the first discharge groove 12b1 and the second discharge groove 12b2.
[0079] Reference Figure 4 , the flow path width of the vertical crossing part (dashed circle) may gradually decrease toward the first discharge groove 12b1 and the second discharge groove 12b2.
[0080] In addition, the flow path of the vertical crossing part (dashed circle) may have a structure in which an inner right angle 20 and an outer rounded corner 21 face each other.
[0081] Reference Figure 2, the first connection groove 12d1 and the second connection groove 12d2 may each include: a first section (①) having a first average depth; a second section (②) having a second average depth; and a third section (③) having a third average depth, where the first average depth may be greater than the second average depth, and the second average depth may be greater than the third average depth.
[0082] The first section (①) and the third section (③) may each have substantially the same groove depth along the flow direction of the coating solution, and the second section (②) may have a groove depth that gradually decreases along the flow direction of the coating solution.
[0083] The groove depth may be measured based on each measurement point of the flow path at the lowest point having the lowest depth (e.g., Figure 3 the center point of the bottom surface in the cross-sectional view of the groove shown).
[0084] The groove depth of the third section (③) may be substantially the same as the depths of the first discharge groove 12b1 and the second discharge groove 12b2.
[0085] The groove depth of the third section (③) may be substantially the same as the depth of the bridging groove 12e.
[0086] The depths of the first bent groove 12c1 and the second bent groove 12c2 may be substantially the same as the depth of the first section (①).
[0087] In one embodiment, the ratio of the depth of the third section (③) to the depth of the first section (①) may be 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less.
[0088] In one embodiment, the ratio of the depth of the first section (①) to the thickness of the gasket body 11 may be 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, or 30% or less.
[0089] In one embodiment, the slope (△Z / △Y) of the second section (②) may be 0.07 or less, 0.05 or less, 0.04 or less, 0.03 or less, and 0.02 or less. Here, △Z is the change amount in the Z-axis direction, and △Y is the change amount in the Y-axis direction.
[0090] In a specific embodiment, the thickness of the gasket body 11 may be 1.5 mm, the depth of the first section (①) may be 1.0 mm, the depth of the third section (③) may be 0.5 mm, the length of the second section (②) in the Y-axis direction may be 10 mm, and the slope (△Z / △Y) of the second section (②) may be 0.05.
[0091] Reference Figure 3, when observed from a cross-section E cut in a direction perpendicular to the flow of the coating solution, the grooves forming the flow path 12 may have a rounded bottom. If the bottom of the groove has a rounded shape, the coating quality can be improved by preventing the coating solution from stagnating in areas where the flow of the coating solution is weak.
[0092] In the spacer 10, since the depth of the flow path gradually or stepwise decreases in the direction of the flow of the coating solution, the pressure of the flow path increases toward the first discharge groove 12b1 and the second discharge groove 12b2. In addition, the bridging groove 12e equalizes the flow path pressures of the first discharge groove 12b1 and the second discharge groove 12b2. Therefore, the spacer 10 can improve the uniformity of the coating quality. In particular, the coating width deviation between the coating layer formed by the coating solution discharged from the first discharge groove 12b1 and the coating layer formed by the coating solution discharged from the second discharge groove 12b2 can be minimized.
[0093] Reference Figure 4 , the bridging groove 12e intersects the first connection groove 12d1 and the first discharge groove 12b1 perpendicularly.
[0094] In the perpendicular intersection (dashed circle), the flow path width gradually decreases in the direction of the flow of the coating solution (arrow direction).
[0095] The perpendicular intersection (dashed circle) may have a structure in which the inner right angle 20 and the outer rounded corner 21 face each other when the spacer 10 is observed in the Z-axis direction.
[0096] The rounded corner 21 may include a curved portion 21a having a radius of curvature when the spacer 10 is observed in the Z-axis direction and a straight portion 21b smoothly connected to the curved portion 21a.
[0097] The angle (θ) formed between the straight portion 21b and the outer line of the first connection groove 12d1 may be 110 to 130 degrees.
[0098] Due to the perpendicular intersection (dashed circle), the first discharge groove 12b1 is spaced outward from the first connection groove 12d1 in the width direction X. Therefore, the coating solution passing through the first connection groove 12d1 does not directly move to the first discharge groove 12b1, but moves to the first discharge groove 12b1 via the perpendicular intersection (dashed circle). This coating solution flow mechanism can prevent the coating quality from deteriorating due to the pulsation generated by the motor of the pump supplying the coating solution. In addition, since the first discharge groove 12b1 is not directly connected to the first connection groove 12d1, foreign matter can be prevented from deeply penetrating into the spacer 10 during the process of cleaning the lip of the slot die coater including the spacer 10. If the penetration of foreign matter can be prevented, the deterioration of the coating quality caused by foreign matter can be prevented.
[0099] Due to the left - right symmetric structure of the spacer 10, Figure 4 The structure shown can be applied in substantially the same manner to the portion where the bridging groove 12e intersects the second connection groove 12d2 and the second discharge groove 12b2.
[0100] Referring again to Figure 1 , the spacer 10 may have at least one fastening hole 22 that passes through the spacer body 11 but does not overlap with the flow path 12.
[0101] When the spacer 10 is installed in the slot die coater, the fastening hole 22 can be used. The inner peripheral surface of the fastening hole 22 can be provided with threads for fastening bolts.
[0102] At least one fastening hole 22 can be provided in the inner region of the spacer body 11 surrounded by the first bending groove 12c1, the first connection groove 12d1, the bridging groove 12e, the second connection groove 12d2, the first bending groove 12c2, and the inflow groove 12a.
[0103] At least two fastening holes 22 can be provided in the region outside the inner region of the spacer body 11.
[0104] To reduce contamination, a coating layer with a low surface friction coefficient can be provided on a part or all of the exposed surfaces of the flow path 12. In one embodiment, the coating layer can contain polytetrafluoroethylene (PTFE). It is not limited to further forming a coating layer on the exposed surface of the spacer body 11.
[0105] Figure 5 is a plan view showing the structure of a spacer 10' according to another embodiment of the present disclosure.
[0106] Referring to Figure 5 , the spacer 10' can include a bridging groove 12e' with a different structure. One end of the bridging groove 12e' can be connected to the first connection groove 12d1, and the other end of the bridging groove 12e can be connected to the second connection groove 12d2. It is desirable to design the connection points of the bridging groove 12e' to be close to the first discharge groove 12b1 and the second discharge groove 12b2.
[0107] The depth of the bridging groove 12e at the points where it is connected to the first connection groove 12d1 and the second connection groove 12d2 can be the same as the depths of the first connection groove 12d1 and the second connection groove 12d2.
[0108] In the spacer 10', the first connection groove 12d1 and the first discharge groove 12b1 can be directly connected to each other, and the second connection groove 12d2 and the second discharge groove 12b2 can be directly connected to each other.
[0109] The first connection groove 12d1 and the first discharge groove 12b1 are not located on the same line along the longitudinal direction Y, and the second connection groove 12d2 and the second discharge groove 12b2 are also not located on the same line along the longitudinal direction Y. This structure is substantially the same as the above-described spacer 10.
[0110] The connection portions of the first connection groove 12d1 and the first discharge groove 12b1 and the connection portions of the second connection groove 12d2 and the second discharge groove 12b2 may have a structure in which an inner right angle 20' and an outer rounded corner 21' face each other. The inner right angle 20 may have a chamfer. The shape of the outer rounded corner 21' may be substantially the same as the Figure 4 corresponding structure shown.
[0111] The flow path width of the bridging groove 12e' may be relatively smaller than the flow path widths of the first connection groove 12d1 and the second connection groove 12d2.
[0112] The design of the flow path width and depth of the bridging groove 12e' as described above substantially increases the flow path pressure of the first discharge groove 12b1 and the second discharge groove 12b2, thereby improving the coating quality.
[0113] The spacers 10, 10' according to an embodiment of the present disclosure may be included in a slot die coater.
[0114] Figure 6 is a cross-sectional view showing the configuration of a slot die coater 30 according to an embodiment of the present disclosure, Figure 7 is a plan view showing a slot die coater 10 according to an embodiment of the present disclosure.
[0115] Referring to Figure 6 , the slot die coater 30 may include the above-described spacer 10. The spacer 10 may be replaced with a spacer 10' according to another embodiment.
[0116] The slot die coater 30 may further include a first slot die block 31 and a second slot die block 32. The first slot die block 31 is coupled to one side of the spacer body 11 of the spacer 10 to face the exposed surface of the flow path 12 of the spacer 10, and the second slot die block 32 is coupled to the other side of the spacer body 11 to face the first slot die block 31.
[0117] The first slot die block 31 may include a coating solution supply unit 33 that communicates with the inflow groove 12a of the spacer 10.
[0118] The coating solution supply unit 33 may include: a coating solution introduction chamber 33a recessed in the thickness direction of the first slot die block 31; a coating solution inflow hole 33b communicating with the coating solution introduction chamber 33a and perforated in the thickness direction of the first slot die block 31; and a coating solution supply pipe 33c having one end connected to the coating solution inflow hole 33b and the other end connected to a pump (not shown).
[0119] The first slot die block 31 and the second slot die block 32 may be coupled by means of at least one bolt fastening structure 34.
[0120] The bolt fastening structure 34 may have: a bolt fastening hole 34a formed in the first slot die block 31 and having threads formed on its inner circumferential surface; a bolt guiding hole 34b formed in the second slot die block 32 to guide the insertion of a bolt from the outside; and a bolt 34c inserted through the bolt guiding hole 34b and coupled to the bolt fastening hole 34a.
[0121] The detailed structure of the bolt fastening structure 34 is not limited to this embodiment. The bolt fastening hole 34a may be formed in the second slot die block 32, and the bolt guiding hole 34b may be formed in the first slot die block 31. In addition, various bolt fastening structures known in the art may be employed.
[0122] The first slot die block 31 and the second slot die block 32 may be coupled to each other by other mechanical methods (such as welding) other than the bolt fastening method.
[0123] Reference Figure 7 , the slot die coater 30 may include a plurality of spacer shims 10. The plurality of spacer shims 10 may be arranged at regular intervals in the X-axis direction.
[0124] The slot die coater 30 may simultaneously form a plurality of coating layers corresponding to twice the number of spacer shims 10 on the surface of the substrate 35 ( Figure 6 ) along the moving direction of the substrate 35, and the substrate 35 moves in the Y-axis direction. In one embodiment, when the number of spacer shims 10 is 7, 14 coating layers may be simultaneously formed on the surface of the substrate 35.
[0125] The substrate 35 may be conveyed in close contact with a roller 36, as Figure 6 shown, and the slot die coater 30 may continuously form a coating layer on the surface of the substrate 35 while the substrate 35 is conveyed in close contact with the roller 36. The slot die coater 30 may improve the coating quality by uniformly forming the width of the coating layer in a direction perpendicular to the conveying direction of the substrate 35.
[0126] Next, a coating method using the slot die coater 30 will be described.
[0127] Figure 8 is a flowchart conceptually showing a coating method according to an embodiment of the present disclosure.
[0128] First, a substrate 35 having a pair of short sides and a pair of long sides extending between the pair of short sides is prepared. The short sides extend in the X-axis direction, and the long sides extend in the Y-axis direction. The drawings show only a part of the substrate 35.
[0129] Next, a plurality of first coating layers C1 are formed on one surface of the substrate 35 along the long side direction Y, and the plurality of first coating layers C1 are formed at regular intervals in the width direction X. In this step, an uncoated portion 35a extending in the long side direction Y is formed between the adjacent first coating layers C1 in the width direction X. Here, the uncoated portion 35a refers to an area of the substrate 35 without the first coating layer C1. The uncoated portion 35a has a strip shape extending in the long side direction Y.
[0130] Next, a slot die coater 30 according to an embodiment of the present disclosure is prepared.
[0131] Subsequently, as Figure 6 shown, while the substrate 35 is being conveyed by the roller 36, the slot die coater 30 is used to simultaneously form a second coating layer C2 covering the boundary between each first coating layer C1 and the uncoated portion 35a along the conveyance direction of the substrate 35.
[0132] If the slot die coater 30 includes a plurality of spacer gaskets 10, a plurality of pairs of second coating layers C2 can be formed. A pair of second coating layers C2 can face each other in the short side direction X, and the uncoated portion 35a is interposed therebetween.
[0133] For example, when the total number of the spacer gaskets 10 is 7, a total of 7 pairs of second coating layers C2 can be formed on the substrate 35.
[0134] A plurality of pumps 37 can be used to supply the coating solution to the slot die coater 30. The number of the pumps 37 corresponds to the number of the spacer gaskets 10. Each pump 37 can independently supply the coating solution to each spacer gasket 10 by means of the solution supply unit 33. In this case, when the second coating layer C2 is formed, the ejection pressure of the coating solution discharged through the first discharge groove 12b1 and the second discharge groove 12b2 can be maintained uniform. If the ejection pressure of the coating solution is uniform, the width of the coating layer can be uniformly formed along the conveyance direction of the substrate 35.
[0135] In a preferred embodiment, the substrate 35 may be a metal foil current collector, the first coating layer C1 may be a coating layer of an electrode active material, and the second coating layer C2 may be an insulating coating layer.
[0136] The metal foil current collector may be a copper foil current collector or an aluminum foil current collector. The electrode active material may be a positive electrode active material or a negative electrode active material known in the art.
[0137] Next, comparative examples and examples of the present disclosure will be described.
[0138] Figure 9 FIG. is a photograph partially showing the current collector 35 immediately after the positive electrode active material layer C1 and the insulating coating layer C2 are formed on one surface of the current collector 35 made of aluminum foil using the slot die coater 30, and the slot die coater 30 includes a spacer according to a comparative example of the present disclosure, in which the depths of the bent grooves 12c1, 12c2, the connecting grooves 12d1, 12d2, the bridging groove 12e, and the discharge grooves 12b1, 12b2 are all designed to have a constant depth of 1.0 mm.
[0139] Reference Figure 9 In the portion shown by the dashed box in, some coating sections were confirmed, in which the insulating coating layer C2 does not overlap with the positive electrode active material layer C1 and is slightly spaced apart. Therefore, if the depth of the flow path 12 is designed to be constant along the length direction Y of the spacer 10, it can be understood that there are limitations in uniformly controlling the width of the coating layer in the direction perpendicular to the conveying direction of the substrate.
[0140] As a reference, if there is a section where a part of the insulating coating layer C2 does not overlap with the positive electrode active material layer C1, the function of the insulating coating layer C2 cannot be achieved. The current collector 35 can be manufactured as a positive electrode by cutting the center of the uncoated portion 35a. The positive electrode can be used together with a separator and a negative electrode to manufacture a wound core type electrode assembly. In this case, the section where a part of the insulating coating layer C2 does not overlap with the positive electrode active material layer C1 will contact the end of the negative electrode active material opposite to the positive electrode active material layer C1 (with a separator interposed therebetween), resulting in an internal short circuit.
[0141] Figure 10is a photograph according to an embodiment of the present disclosure, which shows a current collector 35 made of aluminum foil immediately after forming a positive electrode active material layer C1 and an insulating coating layer C2 using a slot die coater 30 including a spacer 10. The depth of the bending grooves 12c1 and 12c2 is designed to be 1 mm, the depth of the first section (①) of the connecting grooves 12d1 and 12d2 is designed to be 1 mm, and the depth of the third section (③) of the connecting grooves 12d1 and 12d2 is designed to be 0.5 mm. The length of the second section (②) of the connecting grooves 12d1 and 12d2 is designed to be 10 mm, and the depth of the bridging groove 12e and the discharge grooves 12b1 and 12b2 is designed to be 0.5 mm.
[0142] Reference Figure 10 , it can be found that the insulating coating layer C2 overlaps well with the positive electrode active material layer C1 with a constant width. In addition, throughout the entire section of the current collector 35, no coating section was found where the insulating coating layer C2 did not overlap with the positive electrode active material layer C1 and was thus slightly spaced apart. Therefore, it can be understood that when forming a coating layer using a slot die coater 30 including the spacer 10 according to the present disclosure, the width of the coating layer can be uniformly formed in a direction perpendicular to the conveyance direction of the substrate.
[0143] Figure 11 is a graph showing the results of measuring the average thickness of the insulating coating layer for each uncoated line when forming 6 pairs of insulating coating layers in a total of 6 uncoated lines using the slot die coater in the comparative example and the embodiment of the present disclosure after coating 7 rows of positive electrode active material layers with a width of 125.5 mm at intervals of 10 mm on one surface of an aluminum current collector.
[0144] Reference Figure 11 , the width of the insulating coating layer in the embodiment is relatively larger than that in the comparative example. In this embodiment, the flow path depth of the spacer 10 gradually or gradually decreases along the conveyance direction of the coating solution, thereby increasing the ejection pressure of the coating solution. Therefore, it can be found that the present disclosure can increase the controllable width of the coating layer. In addition, the width deviation of each line of the insulating coating layer formed according to this embodiment is smaller than the width deviation of each line of the insulating coating layer formed according to the comparative example. Therefore, in the present disclosure, when using a slot die coater 30 including a plurality of spacers 10 to simultaneously form a plurality of coating layers, the width deviation of each line of the coating layer can also be minimized.
[0145] The present disclosure has been described in detail. However, it should be understood that although the preferred embodiments of the present disclosure are shown, the detailed description and specific examples are given only by way of illustration, because various changes and modifications within the scope of the present disclosure will become apparent to those skilled in the art according to this detailed description.
Claims
1. A spacer, the spacer comprising: A plate-shaped spacer body having a predetermined width, length, and thickness; And A flow path having a groove recessed in the thickness direction on one surface of the spacer body, Wherein the flow path includes: An inflow groove into which a coating solution is introduced in the thickness direction; A first discharge groove and a second discharge groove, the first discharge groove and the second discharge groove being arranged to be spaced apart in the width direction to independently discharge the coating solution in the length direction; A first bending groove and a second bending groove, the first bending groove and the second bending groove being configured to branch from one side and the other side of the inflow groove respectively, and extend in the width direction and the length direction; and A first connection groove and a second connection groove, the first connection groove and the second connection groove being configured to extend in the length direction from the first bending groove and the second bending groove respectively, and communicate with the first discharge groove and the second discharge groove.
2. The spacer according to claim 1, Among them, The first discharge groove and the first connection groove are spaced apart from each other in the width direction and do not overlap each other in the length direction, and Wherein the second discharge groove and the second connection groove are spaced apart from each other in the width direction and do not overlap each other in the length direction.
3. The spacer according to claim 1, Among them, When the average flow path width of the first bending groove and the average flow path width of the second bending groove are defined as a first flow path width, the average flow path width of the first connection groove and the average flow path width of the second connection groove are defined as a second flow path width, and the average flow path width of the first discharge groove and the average flow path width of the second discharge groove are defined as a third flow path width, The first flow path width is greater than the second flow path width, and the second flow path width is greater than the third flow path width.
4. The spacer according to claim 1, Among them, When the maximum separation distance in the width direction between the first bending groove and the second bending groove is defined as a first separation distance, the maximum separation distance in the width direction between the first connection groove and the second connection groove is defined as a second separation distance, and the maximum separation distance in the width direction between the first discharge groove and the second discharge groove is defined as a third separation distance, The first separation distance is less than the second separation distance, and the second separation distance is less than the third separation distance.
5. The spacer according to claim 1, Among them, The flow path further includes a bridging groove, Wherein one end of the bridging groove is inserted between the first discharge groove and the first connection groove, and Wherein the other end of the bridging groove is inserted between the second discharge groove and the second connection groove.
6. The spacer according to claim 5, Among them, The flow path width of the bridging groove is greater than the flow path widths of the first discharge groove and the second discharge groove.
7. The spacer according to claim 5, Among them, The depth of the bridging groove is substantially the same as the depth of the first discharge groove and the depth of the second discharge groove.
8. The spacer according to claim 1, Among them, The flow path further includes a bridging groove, wherein one end of the bridging groove communicates with the first connecting groove, and wherein the other end of the bridging groove communicates with the second connecting groove.
9. The spacer according to claim 8, Among them, The flow path width of the bridging groove is smaller than the flow path width of the first connecting groove and smaller than the flow path width of the second connecting groove.
10. The spacer according to claim 8, Among them, The bridging groove communicates with the first connecting groove and the second connecting groove at the same depth.
11. The spacer according to claim 5, Among them, The bridging groove intersects the first discharge groove and the second discharge groove substantially perpendicularly, and the flow path width of the intersection portion gradually decreases toward the discharge groove.
12. The spacer according to claim 11, Among them, The flow path of the intersection portion has a structure in which an inner right angle and an outer rounded corner face each other.
13. The spacer according to claim 1, Among them, The first connecting groove and the second connecting groove respectively include a first section having a first average depth, a second section having a second average depth, and a third section having a third average depth along the length direction of the spacer body, wherein the first average depth is greater than the second average depth, and wherein the second average depth is greater than the third average depth.
14. The spacer according to claim 13, Among them, The first section and the third section respectively have substantially the same groove depth along the flow direction of the coating solution, and wherein the second section has a groove depth that gradually decreases along the flow direction of the coating solution.
15. The spacer according to claim 13, Among them, The groove depth of the third section is substantially the same as the depth of the first discharge groove and the second discharge groove.
16. The spacer according to claim 1, Among them, When observed in a cross-section perpendicular to the flow direction of the coating solution, the grooves forming the flow path have rounded bottoms.
17. The spacer according to claim 1, Among them, The spacer has at least one fastening hole that passes through the spacer body but does not overlap with the flow path.
18. The spacer according to claim 1, Among them, The spacer includes a coating layer formed on the exposed surface of the flow path in the thickness direction of the spacer body.
19. The spacer according to claim 18, Among them, The coating layer contains polytetrafluoroethylene.
20. A slot die coater, the slot die coater includes: At least one spacer according to any one of claims 1 to 19; A first slot die block, the first slot die block being coupled to one side of the spacer body to face the exposed surface of the flow path in the thickness direction of the spacer body; A second slot die block, the second slot die block being coupled to the other side of the spacer body to face the first slot die block; And A coating solution supply unit configured to communicate with the inflow groove of the spacer.
21. The slot die coater according to claim 20, Among them, The slot die coater includes at least one pump configured to independently supply a coating solution via a coating solution supply unit that communicates with the inflow groove of each spacer.
22. A coating method, the coating method comprising: Preparing a substrate having a pair of short sides and a pair of long sides extending between the pair of short sides; Forming a plurality of first coating layers at a predetermined interval in the long side direction on one surface of the substrate such that a strip-shaped uncoated portion extending in the long side direction is formed between the first coating layers adjacent in the short side direction; Preparing the slot die coater according to claim 20; And Using the slot die coater to form a second coating layer in the long side direction to cover a predetermined width of the boundary between each first coating layer and the uncoated portion adjacent thereto.
23. The coating method according to claim 22, Among them, Simultaneously forming a pair of the second coating layers at the boundary between the uncoated portion and a pair of first coating layers facing the uncoated portion.
24. The coating method according to claim 22, Among them, The substrate is a metal foil current collector, wherein the first coating layer is an active material coating layer, and wherein the second coating layer is an insulating coating layer.