A die coater for coating an active material of a current collector of a secondary battery

Abstract

A mold coating machine is disclosed that can effectively coat current collectors of secondary batteries with two different types of liquids simultaneously. The mold coating machine includes a lower block having a manifold configured to contain a first liquid, an upper block coupled to the lower block and having a second liquid inlet, and a coating machine pad disposed between the upper block and the lower block to form a first slit and a second slit that are open to the front and spaced apart from each other. The coating machine pad has a second liquid flow path on a central guide that extends across the manifold to the front, and a manifold insert configured to support the bottom surface of the central guide is disposed inside the manifold.

Description

Technical Field

[0001] This invention relates to a mold coating machine capable of efficiently coating current collectors of secondary batteries with two different types of liquids simultaneously.

[0002] This application claims priority to Korean Patent Application No. 10-2022-0004233, filed on January 11, 2022, all of which is incorporated herein by reference. Background Technology

[0003] With technological advancements and increasing demands for mobile devices, the demand for rechargeable batteries is also rapidly growing. Among rechargeable batteries, lithium-ion batteries, with their high energy density, high operating voltage, and excellent storage and lifespan characteristics, are widely used as energy sources for various electronic products and mobile devices.

[0004] Lithium-ion batteries employ electrodes on which an active material layer and an insulating layer are formed on the surface of a current collector. The electrodes are manufactured using a coating apparatus such as a die coater, where an electrode slurry containing the active material and an insulating coating liquid containing the insulating material are applied to the surface of the current collector, causing a portion of the end of the electrode mixture layer to overlap, and then dried.

[0005] Figure 1 A conventional die coating machine 1 for applying electrode paste is shown. The die coating machine 1 includes an upper block 2 and a lower block 3, with a gasket 4 inserted between the upper block 2 and the lower block 3, and the upper block 2, the lower block 3, and the gasket 4 are fastened and coupled together using a plurality of bolt components. The lower block 3 is provided with a manifold 5 for receiving a predetermined volume of electrode paste, and the manifold 5 communicates with an external electrode paste supply component (not shown).

[0006] Here, the gasket of the die coater is used to form a slit of appropriate height between the upper and lower blocks, while also restricting the flow direction of the electrode paste to allow it to exit towards the slit, and acting as a seal between the upper and lower blocks to prevent electrode paste leakage into areas other than the slit. The gasket of the die coater has guides protruding from both ends along the width direction, and the width of the electrode paste applied to the current collector depends on the distance between the guides.

[0007] The insulating coating liquid is applied to both ends of the electrode paste applied to the current collector in the width direction. Generally, after the electrode paste is applied to the current collector, the insulating coating liquid is applied using a separate device in an additional step. However, from a production efficiency perspective, it is not advisable to apply the electrode paste and insulating coating liquid to the current collector in a separate step.

[0008] To overcome the aforementioned limitations, a technique is introduced that forms independent slits within a die coating core to discharge electrode slurry and insulating coating liquid. However, when either of the two liquids leaks within the die coating machine, they mix together, or are discharged from the slit outlet after mixing, leading to quality defects in the current collector.

[0009] [Related Literature]

[0010] (Patent Document 1) Japanese Patent Publication No. 2021-010867 (published on February 4, 2021) Summary of the Invention

[0011] (Technical issue)

[0012] The present invention aims to provide a mold coating machine that can effectively coat the current collector of a secondary battery with two different types of liquids simultaneously.

[0013] However, the technical problems to be solved by the present invention are not limited to the above-mentioned problems, and those skilled in the art can clearly understand other problems not mentioned from the following description of the present invention.

[0014] (Technical Solution)

[0015] One aspect of the present invention provides a mold coating machine capable of effectively coating a current collector of a secondary battery simultaneously with two different types of liquids. The mold coating machine includes a lower block having a manifold configured to receive a first liquid, an upper block connected to the lower block and having a second liquid inlet, and a coating machine pad disposed between the upper block and the lower block to form a first slit and a second slit spaced apart from each other and open to the front. The coating machine pad has a second liquid flow path on a central guide extending across the manifold to the front, and a manifold insert configured to support the bottom surface of the central guide is disposed inside the manifold.

[0016] The coating machine pad may include a base extending in the width direction, a first side guide and a second side guide extending from both ends of the base, and a center guide extending from the center of the base.

[0017] The space between the first side guide and the center guide, and the space between the second side guide and the center guide, can form a first slit for discharging the first liquid.

[0018] The outlet of the second liquid flow path, which is formed in the form of a groove on the central guide, can form a second slit.

[0019] The second liquid flow path on the central guide can form a pair of second liquid flow paths, and the second liquid flow path can also be formed on each of the first side guide and the second side guide.

[0020] The lower block may be provided with a first liquid inlet communicating with the manifold. The first liquid inlet may be located below the central guide. The manifold insert may have a structure with open surfaces on both sides to avoid blocking the first liquid inlet.

[0021] The two sides of the manifold insert can form an arched structure, and the width of the arched structure can be greater than or equal to the diameter of the first liquid inlet.

[0022] The manifold insert may have coupling grooves on the bottom and sides surrounding the central guide.

[0023] The coupling groove of the manifold insert may be provided with a tapered portion, in which the thickness of the two side walls gradually decreases towards the front.

[0024] The manifold insert can be made of polytetrafluoroethylene (PTFE) resin.

[0025] The manifold insert may have a gasket made of ethylene propylene rubber on the surface that contacts the bottom surface of the center guide.

[0026] The first liquid can be an electrode paste, and the second liquid can be an insulating coating liquid.

[0027] (Beneficial effects)

[0028] According to the mold coating machine of the present invention having the above-described structure, the upper surface of the manifold insert fixed in the manifold firmly supports the lower surface of the center guide, preventing the center guide of the coating machine gasket from bending towards the manifold and ensuring it remains in close contact with the upper block at all times. Therefore, two different liquids will not mix within the mold coating machine.

[0029] Furthermore, the technical effects that can be obtained by the present invention are not limited to those described above, and those skilled in the art will clearly understand from the following description of the present invention other effects not mentioned. Attached Figure Description

[0030] However, the following figures accompanying this specification illustrate exemplary embodiments of the invention and, together with the detailed description of the invention to be described below, are used to further aid in understanding the technical concept of the invention. Therefore, the invention should not be construed as being limited to the details shown in the figures.

[0031] Figure 1 This is a diagram showing the structure of a mold coating machine according to relevant technology.

[0032] Figure 2This is an exploded perspective view showing a mold coating machine according to one embodiment of the present invention.

[0033] Figure 3 This is a perspective view showing a mold coating machine according to one embodiment of the present invention.

[0034] Figure 4 This is a front view of a mold coating machine according to an embodiment of the present invention.

[0035] Figure 5 It is along Figure 3 A cross-sectional view of a mold coating machine with the line "AA".

[0036] Figure 6 This is a perspective view showing a manifold insert according to an embodiment of the present invention.

[0037] Figure 7 This is a perspective view showing a manifold insert according to another embodiment of the present invention.

[0038] Figure 8 This shows the application. Figure 7 A diagram showing the structure of a mold coating machine for manifold inserts. Detailed Implementation

[0039] This invention can be modified in various forms and can have various implementation methods. Therefore, the specific implementation methods will be described in detail below.

[0040] However, these embodiments should not be construed as limiting the invention to the specific implementations, but should be interpreted as including all modifications, equivalents or alternatives that fall within the spirit and technical scope of the invention.

[0041] In this invention, the terms “comprising,” “having,” etc., are used to specify the presence of the features, numbers, steps, operations, components, elements, or combinations thereof described herein, and they do not exclude the presence or addition of one or more other features, numbers, steps, operations, components, elements, or combinations thereof.

[0042] Furthermore, in this invention, when a portion of a layer, film, region, plate, etc., is described as being "on" another portion, this includes not only the case where the portion is "directly on" the other portion, but also the case where another portion exists between the portion and the other portion. Conversely, when a portion of a layer, film, region, plate, etc., is described as being "below" another portion, this includes not only the case where the portion is "directly below" the other portion, but also the case where another portion exists between the portion and the other portion. Additionally, in this application, being "disposed on" can include not only being disposed on an upper portion, but also being disposed on a lower portion.

[0043] This invention relates to a mold coating machine capable of efficiently coating current collectors of secondary batteries with two different types of liquids simultaneously.

[0044] In one example, the mold coating machine of the present invention includes a lower block having a manifold configured to contain a first liquid, an upper block coupled to the lower block and having a second liquid inlet, and a coating machine pad disposed between the upper block and the lower block to form a first slit and a second slit that are open to the front and spaced apart from each other.

[0045] Here, the coating machine pad is provided with a second liquid flow path on the central guide, which extends across the manifold to the front, and in order to correspond to the second liquid flow path, a manifold insert is provided in the manifold to support the lower surface of the central guide.

[0046] According to the mold coating machine of the present invention, two different types of first and second liquids, such as electrode slurry and insulating coating liquid, are simultaneously discharged. In particular, the internal mixing of the first and second liquids is effectively prevented due to the gap created by the pressure of the second liquid flowing through the flow path, causing the central guide to bend towards the manifold. Therefore, according to the mold coating machine of the present invention, the current collector of a secondary battery can be effectively coated with two different types of liquids simultaneously.

[0047] [Invention Method]

[0048] Below, some embodiments of the mold coating machine according to the present invention will be described in detail with reference to the accompanying drawings.

[0049] (First Implementation)

[0050] Figure 2 This is an exploded perspective view showing a mold coating machine 10 according to an embodiment of the present invention, and Figure 3 This is a perspective view showing a mold coating machine 10 according to an embodiment of the present invention.

[0051] As described above, the present invention relates to a mold coating machine 10, capable of efficiently coating the current collector of a secondary battery simultaneously with two different types of liquids. These two different types of liquids can be, for example, an electrode paste and an insulating coating liquid. The following description is to be understood as an embodiment where the first liquid LQ1 is an electrode paste and the second liquid LQ2 is an insulating coating liquid.

[0052] The mold coating machine 10 of the present invention includes a lower block 100, an upper block 200 and a coating machine pad 300 disposed therebetween, and also includes a manifold insert 400 for supporting a portion of the coating machine pad 300.

[0053] The lower block 100 occupies approximately half of the body of the mold coating machine 10 and is provided with a manifold for containing a predetermined amount of first liquid LQ1. The upper block 200, coupled to the lower block 100, occupies the remaining half and is provided with a second liquid inlet 210. Here, the upper and lower parts are defined according to the accompanying drawings and do not restrict the actual installation direction of the mold coating machine 10.

[0054] For reference only. Figure 2 A first liquid inlet 120 communicating with a manifold formed in the lower block 100 is shown, but the first liquid inlet 120 may be formed in the upper block 200. On the other hand, a second liquid inlet 210 should be formed in the upper block 200. This is because the communication direction of the second liquid flow path 350 (described below) formed in the form of a groove on the coating machine pad 300 is limited to the upper block 200.

[0055] A coating machine gasket 300 is positioned between the upper block 200 and the lower block 100 to form a first slit 360 and a second slit 370 that open towards the front. The first slit 360 for discharging a first liquid LQ1 and the second slit 370 for discharging a second liquid LQ2 are spatially spaced apart from each other. The detailed structure of the coating machine gasket 300 will be described in detail below. The coating machine gasket 300 is substantially positioned between the upper block 200 and the lower block 100 and is used to form slits, each slit having a height suitable for discharging liquid. In addition to the above description, the coating machine gasket 300 also restricts the flow direction of liquid flowing into or contained in the die coating machine 10, allowing the liquid to be discharged towards the slits without backflow, and also serves to seal the liquid, preventing leakage to other components besides the slits.

[0056] refer to Figure 2 The coating machine gasket 300 has a second liquid flow path 350 on the central guide 340, which extends across the recessed manifold to the front. In addition, in order to correspond to the second liquid flow path 350, a manifold insert 400 is provided inside the manifold to support the bottom surface of the central guide 340.

[0057] First, to describe the detailed configuration of the coating machine gasket 300, the coating machine gasket 300 includes a base 310 extending in the width direction, a first side guide 320 and a second side guide 330 extending from both ends of the base 310, and a center guide 340 protruding from the central portion of the base 310. The overall external dimensions of the coating machine gasket 300 correspond to the coupling surface dimensions between the upper block 200 and the lower block 100.

[0058] Here, the coating machine pad 300 provided in this invention includes a central guide 340. This is because the mold coating machine 10 of this invention is used for stripe coating, in which the electrode slurry is applied to the current collector in a multi-row manner by dividing one area of ​​the current collector into two or more areas.

[0059] Figure 4 This is a front view of a mold coating machine 10 according to an embodiment of the present invention, shown above. Because a coating machine gasket 300 is inserted between the upper block 200 and the lower block 100, the mold coating machine 10 is divided into two regions: the region between the first side guide 320 and the center guide 340, and the region between the second side guide 330 and the center guide 340. These two regions form a first slit 360, which discharges a first liquid LQ1 contained in a manifold. Because the first slit 360 is centrally separated by the center guide 340, the mold coating machine 10 of the illustrated embodiment forms a mixed layer of electrode slurry divided into two rows.

[0060] Furthermore, the outlet of the second liquid flow path 350, which is formed in the form of a groove in the central guide 340, forms a second slit 370. The second liquid flow path 350 is formed in the shape of a shallow groove that does not pass through the central guide 340. Therefore, the second liquid flow path 350 is spatially separated from the adjacent first slit 360 by the two sidewalls of the central guide 340. In addition, the closed end of the second liquid flow path 350 communicates with the second liquid inlet 210 formed in the upper block 200. Therefore, the second liquid LQ2 supplied through the second liquid inlet 210 flows in the second liquid flow path 350 and is discharged through the second slit 370.

[0061] exist Figure 2 In the illustrated embodiment of the coating machine pad 300, specifically, the second liquid flow path 350 on the central guide 340 is formed as a pair of second liquid flow paths 350, and one second liquid flow path 350 is formed on each of the first side guide 320 and the second side guide 330. That is, the second slit 370 is disposed on both sides of each of the pair of spaced first slits 360. Due to the structure between the first slits 360 and the second slits 370, an insulating layer coated with the second liquid LQ2 is formed at the two corners of the two rows of mixed layers formed by the electrode paste, i.e., the first liquid LQ1.

[0062] According to the above embodiment, two rows of electrode paste can be applied, and insulating coating liquid can be applied simultaneously to the corners of each row of electrode paste. However, due to the structural limitations of the central guide 340 spanning the manifold, there is a problem that the first liquid LQ1 and the second liquid LQ2 can mix within the mold coating machine 10.

[0063] That is, the second liquid LQ2 is pressurized through the second liquid inlet 210 and flows through the second liquid flow path 350, and the center guide 340 bends toward the manifold due to the pressure exerted by the second liquid LQ2 on the second liquid flow path 350. In other words, since the thin center guide 340 spanning the concave manifold is not subjected to additional lower support force, the thin center guide 340 easily bends toward the manifold.

[0064] Therefore, the central guide 340, which bends toward the manifold, is not in close contact with the upper block 200, thus creating a gap between the central guide 340 and the upper block 200. This gap, as the gap between the second liquid LQ2 flowing in the second liquid flow path 350 into the manifold and the first slit 360, causes the first liquid LQ1 and the second liquid LQ2 to mix within the mold coating machine 10.

[0065] According to the present invention, in order to address the structural fragility of the center guide 340, a manifold insert 400 is provided for supporting the bottom surface of the center guide 340, such as... Figure 5 The sectional view is shown.

[0066] Figure 5 It shows along Figure 3 A cross-sectional view of a die-coating machine with line "AA" on it. (Reference) Figure 5 A manifold insert 400, having a shape corresponding to the cross-section (cross-section in the discharge direction) of the manifold, is fixedly inserted into the manifold. The height of the manifold insert 400 corresponds to the depth of the manifold, and the upper surface of the manifold insert 400, fixed in the manifold, supports the bottom surface of the center guide 340. Therefore, the center guide 340 does not bend into the manifold and maintains close contact with the upper block 200, thereby preventing a second fluid leak.

[0067] In the illustrated embodiment, the lower block 100 is provided with a first liquid inlet 120 communicating with the manifold, and the first liquid inlet 120 is also located below the central guide 340. In this case, the manifold insert 400 has a structure in which both sides of the manifold insert 400 are open so as not to block the first liquid inlet 120. That is, the manifold insert 400 has a bridge shape that supports the central guide 340.

[0068] Furthermore, arches 410 can be formed on both sides of the manifold insert 400, and the width of the arches 410 can be greater than or equal to the diameter of the first liquid inlet 120. The curved surface of the arches 410 is similar to an arc, ellipse, or parabola, and does not obstruct the flow of the first liquid LQ1 introduced through the first liquid inlet 120. In addition, forming a width of the arches 410 greater than or equal to the diameter of the first liquid inlet 120 does not reduce the inflow area of ​​the first liquid LQ1.

[0069] In the mold coating machine 10 of the first embodiment, the phenomenon of the central guide 340 bending towards the manifold due to the pressure applied to the second liquid flow path 350 is effectively suppressed by the support of the manifold insert 400. Therefore, the first liquid LQ1 and the second liquid LQ2 do not mix within the mold coating machine 10. Thus, according to the mold coating machine 10 of the present invention, the current collector of the secondary battery can be effectively coated with two different types of liquids simultaneously.

[0070] (Second Implementation)

[0071] The second embodiment of the present invention relates to an embodiment that can further improve the tight contact or coupling between the center guide 340 and the manifold insert 400. Improving the coupling between the center guide 340 and the manifold insert 400 more definitively prevents the mixing of the first liquid LQ1 and the second liquid LQ2 within the mold coating machine 10.

[0072] Figure 6 This is a perspective view showing a manifold insert 400 according to a second embodiment of the present invention. Figure 6 In the second embodiment, the manifold insert 400 is made of polytetrafluoroethylene (PTFE) resin, for example, commercially known as Teflon resin. PTFE resin is a material with excellent chemical resistance, ensuring excellent durability even when in prolonged contact with electrode paste and insulating coating liquid, thus maintaining the downward support force of the manifold insert 400 for extended periods.

[0073] Furthermore, the manifold insert 400 of the second embodiment may further include a gasket 420 made of ethylene propylene rubber on a surface that contacts the bottom surface of the center guide 340. The gasket 420 made of ethylene propylene rubber ensures that the entire bottom surface of the center guide 340 is in uniform and tight contact with the manifold insert 400, thereby ensuring that the downward support force of the manifold insert 400 is evenly distributed across the entire center guide 340.

[0074] Figure 7 This is a perspective view showing another example of a second embodiment of the manifold insert 400. Figure 7 The second embodiment improves the coupling of the center guide 340 in terms of shape. Here, although they are described separately... Figure 6 and 7 Examples are provided, but these examples can be combined and implemented in a manifold insert 400.

[0075] Figure 7The manifold insert 400 includes coupling grooves 430 surrounding the bottom surface and both sides of the central guide 340. The coupling grooves 430 of the manifold insert 400 improve engagement with the central guide 340 and also improve the alignment of the manifold insert 400 with the central guide 340. In other words, the central guide 340 has a structure that is mounted within the coupling grooves 430 of the manifold insert 400. This groove structure allows the central guide 340 and the manifold insert 400 to be aligned and also increases the contact area, thereby achieving a better support structure.

[0076] However, the coupling groove 430 of the manifold insert 400 has sidewalls 432 surrounding both sides of the central guide 340, thus partially occupying the area of ​​the first slit 360. There is a problem that the two sidewalls 432 of the coupling groove 430 may obstruct the flow of the first liquid LQ1 to the first slit 360. Therefore, as... Figure 8 As shown, the coupling groove 430 of the manifold insert 400 may have a tapered portion 434, in which the thickness of the sidewall 432 gradually decreases towards the front. The width of the manifold insert 400 at the front end of the tapered portion 434 is the same as the width of the central guide 340. Therefore, the first liquid LQ1 flowing from the manifold to the first slit 360 flows smoothly along the outer edge of the tapered portion 434. Thus, the manifold insert 400 does not occupy the area of ​​the first slit 360. Of course, the contour of the tapered portion 434 can be formed into various curved shapes other than the straight shape shown.

[0077] As described above, the present invention has been described in more detail with reference to the accompanying drawings and embodiments. Therefore, the configurations described herein or shown in the drawings are merely one embodiment of the present invention and do not represent the full technical essence of the present invention. It should be understood that various equivalent methods and modifications that can replace the embodiments and configurations may exist at the time of filing this application.

[0078] [Explanation of reference numerals in the attached figures]

[0079] 10: Mold coating machine 100: Lower block

[0080] 110: Manifold 120: First liquid inlet

[0081] 200: Upper block 210: Second liquid inlet

[0082] 300: Coating machine gasket; 310: Base

[0083] 320: First side guide component; 330: Second side guide component

[0084] 340: Central guide element; 350: Second liquid flow path

[0085] 360°: First slit; 370°: Second slit

[0086] 400: Manifold insert 410: Arch

[0087] 420: Gasket; 430: Coupling groove

[0088] 432: Side wall; 434: Conical section

[0089] LQ1: First liquid; LQ2: Second liquid

[0090] (Industrial applicability)

[0091] The mold coating machine of the present invention can be used to effectively and simultaneously coat the current collector of a secondary battery with two different types of liquids.

Claims

1. A mold coating machine, comprising: A lower block is provided, which is configured to contain a first liquid; An upper block coupled to the lower block and provided with a second liquid inlet; as well as A coating machine pad is placed between the upper block and the lower block to form a first slit and a second slit that are open to the front and spaced apart from each other. The coating machine gasket is provided with a second liquid flow path on a central guide that extends across the manifold to the front. A manifold insert configured to support the bottom surface of the central guide is disposed inside the manifold. The manifold insert has coupling grooves around at least a portion of the bottom surface of the central guide and at least a portion of each of the two sides of the central guide, for fitting the central guide into the coupling grooves of the manifold insert.

2. The mold coating machine according to claim 1, wherein the coating machine pad includes a base extending in the width direction, a first side guide and a second side guide extending from both ends of the base, and a center guide extending from the center of the base.

3. The mold coating machine according to claim 2, wherein the space between the first side guide and the central guide and the space between the second side guide and the central guide form the first slit for discharging the first liquid.

4. The mold coating machine according to claim 3, wherein the outlet of the second liquid flow path formed in the form of a groove on the central guide forms the second slit.

5. The mold coating machine according to claim 4, wherein: The second liquid flow path on the central guide forms a pair of second liquid flow paths, and The second liquid flow path is also formed on each of the first side guide and the second side guide.

6. The mold coating machine according to claim 1, wherein: The lower block is provided with a first liquid inlet that communicates with the manifold. The first liquid inlet is located below the central guide member, and The manifold insert has a structure with open surfaces on both sides to prevent obstruction of the first liquid inlet.

7. The mold coating machine according to claim 6, wherein the two side surfaces of the manifold insert form an arched structure, and the width of the arched structure is greater than or equal to the diameter of the first liquid inlet.

8. The mold coating machine according to claim 1, wherein the coupling groove of the manifold insert is provided with a tapered portion, wherein the thickness of the two side walls in the tapered portion gradually decreases towards the front.

9. The mold coating machine according to claim 1, wherein the manifold insert is made of polytetrafluoroethylene (PTFE) resin material.

10. The mold coating machine according to claim 9, wherein the manifold insert has a gasket made of ethylene propylene rubber on the surface that contacts the bottom surface of the central guide.

11. The mold coating machine according to claim 1, wherein: The first liquid is an electrode paste; and The second liquid is an insulating coating liquid.

Images