Slid die

Abstract

To provide a slit die that is able to prevent sedimentation of particles contained in a coating liquid in a manifold.SOLUTION: A slit die includes: a manifold that is formed long in one direction and stores a coating liquid; and an ejection port that is connected to the manifold via a slit and ejects the coating liquid. A plurality of block portions each of which adjusts a volume of the manifold by its being taken in and out of the manifold are provided. The plurality of block portions are provided side by side in a longitudinal direction of the manifold. Each of the block portions is taken in and out of the manifold according to a dimension of the slit in the longitudinal direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a slit die for applying a coating liquid to a substrate. [Background technology]

[0002] In a coating device used to form the positive and negative electrodes of lithium-ion batteries, a coating film is formed by applying a slurry (hereinafter referred to as coating liquid) made by mixing an active material, a binder, and a conductive additive in a solvent to a sheet-like substrate such as aluminum foil or copper foil that is being transported, and the formed coating film is then dried using a drying device.

[0003] Such a coating device is provided with a slit die for coating a coating liquid. The slit die 900 is formed long in one direction and, as shown in FIG. 6, is configured by combining a first divided body 910 having a tapered first lip 911 and a second divided body 920 having a tapered second lip 921 with a shim 931 sandwiched between them. As shown in FIGS. 6 and 7(a) (a cross-sectional view taken along the arrows CC in FIG. 6), the slit die 900 has formed therein a manifold 941 formed long in the longitudinal direction of the slit die 900 for storing the coating liquid, and a slit 942 connected to the manifold 941. In addition, a discharge port 943, which is an open end of the slit 942, is formed between the first lip 911 and the second lip 921. That is, a coating liquid 951 stored in the manifold 941 is discharged from the discharge port 943 through the slit 942 (for example, see Patent Document 1 below).

[0004] In the slit die 900, the dimension in the longitudinal direction of the coating liquid 951 to be applied (hereinafter, coating width) is defined by the inner dimension in the longitudinal direction of the shim 931. That is, as shown in Fig. 7(a), the dimension of the slit 942 in the longitudinal direction is defined by the inner dimension T of the shim 931, and the coating liquid 951 is applied onto the substrate with a coating width that is substantially the same as the longitudinal dimension of the slit 942. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-041501 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the slit die 900 has a problem in that it is difficult to respond to changes in the coating conditions of the coating liquid 951. In particular, when the coating width is changed, defects may occur in the coating of the coating liquid 951.

[0007] Specifically, the coating width is changed by replacing the shim 931 sandwiched between the first divided body 910 and the second divided body 920. For example, when changing the coating width to a width smaller than the coating width defined by the shim 931a having the inner dimension T shown in FIG. 7(a), the coating width is reduced by replacing the shim 931 with a shim 931b (see FIG. 7(b)) having the inner dimension U smaller than the inner dimension T. When the coating width is changed using the shim 931 in this manner, as shown in FIG. 7(b), a portion of the manifold 941 extending in the longitudinal direction beyond the slit 942, i.e., a retention portion S where the flow of the coating liquid 951 slows down and the coating liquid 951 stagnates, is formed. In this retention portion S, particles such as the active material contained in the coating liquid 951 may settle. When a lithium-ion battery is manufactured by applying the coating liquid 951 in this state, the performance of the lithium-ion battery is reduced.

[0008] The present invention has been made in consideration of the above problems, and aims to provide a slit die that can suppress the settling of particles contained in a coating liquid in a manifold. [Means for solving the problem]

[0009] The slit die of the present invention, which solves the above-mentioned problems, is a slit die comprising a manifold formed long in one direction and which stores a coating liquid, and a discharge port which is connected to the manifold via a slit and discharges the coating liquid, and further comprising a block part which adjusts the volume of the manifold by being inserted into or removed from the manifold, and a plurality of the block parts are arranged in a line in the longitudinal direction of the manifold, and each of the block parts is inserted into or removed from the manifold according to the dimension of the slit in the longitudinal direction.

[0010] According to the slit die, the volume of the manifold can be adjusted by each of the multiple block portions according to the dimension of the slit in the longitudinal direction of the manifold, so that even if a portion of the manifold that extends further in the longitudinal direction than the slit, i.e., a retention portion where the coating liquid stagnates due to a slower flow of the coating liquid, is formed, the retention portion can be narrowed, thereby preventing particles contained in the coating liquid from settling in the manifold.

[0011] Furthermore, the block portion may have a cross section in the longitudinal direction that has substantially the same shape as a cross section of the manifold in the longitudinal direction, and the block portion may define an end of a liquid storage area in the manifold that stores the coating liquid.

[0012] According to this configuration, the block portions define the ends of the liquid storage area in the manifold that stores the coating liquid. That is, the liquid storage area is formed between the two block portions inserted into the manifold. Here, by inserting the block portions into the manifold so that the end of the liquid storage area in the longitudinal direction is aligned with the end of the slit in the longitudinal direction, the retention area can be eliminated. This can further suppress settling of particles contained in the coating liquid in the manifold.

[0013] Furthermore, the block portions may be configured such that the insertion amount into the manifold can be adjusted individually.

[0014] According to this configuration, the insertion amount of each block portion into the manifold can be adjusted individually, so that the volume of the manifold can be finely adjusted.

[0015] Further, each of the block portions may be connected to an electric actuator that moves the block portion in and out of the manifold.

[0016] With this configuration, the insertion amount of each block section into the manifold can be adjusted using an electric actuator, which has better controllability than other drive sources such as air cylinders, allowing for more precise adjustment of the manifold volume. [Effects of the Invention]

[0017] According to the measuring device of the present invention, it is possible to prevent particles contained in the coating liquid from settling in the manifold. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing a coating device equipped with a slit die according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram illustrating a slit die according to one embodiment of the present invention. [Figure 3] FIG. 2 is a diagram illustrating a slit die according to one embodiment of the present invention. [Figure 4] FIG. 2 is a diagram illustrating a slit die according to one embodiment of the present invention. [Figure 5] FIG. 1 is a diagram showing one variation of a slit die in one embodiment of the present invention. [Figure 6] FIG. 1 is a diagram showing a conventional slit die. [Figure 7] FIG. 7 is a cross-sectional view taken along the line CC in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment of the slit die of the present invention will be described with reference to the drawings. In the following description, the three axes of a Cartesian coordinate system are designated as X, Y, and Z, the horizontal direction is referred to as the X-axis direction and the Y-axis direction, and the direction perpendicular to the XY plane (i.e., the vertical direction) is referred to as the Z-axis direction.

[0020] Fig. 1 is a schematic diagram showing a coating apparatus 100 equipped with a slit die 3 according to one embodiment of the present invention. Fig. 2 and Fig. 3 are diagrams for explaining the slit die 3 according to one embodiment of the present invention, with Fig. 2 being a cross-sectional view taken along the line A-A in Fig. 1 and Fig. 3 being a cross-sectional view taken along the line B-B in Fig. 1.

[0021] 1, the coating apparatus 100 includes a conveying device 2 that conveys a substrate 1, a slit die 3 that applies a coating liquid 11 to the substrate 1, and a supply mechanism 4 that supplies the coating liquid 11 to the slit die 3. The coating liquid 11 is supplied to the slit die 3 by the supply mechanism 4, whereby the coating liquid 11 is applied to the surface of the substrate 1 being conveyed by the conveying device 2, thereby forming a coating film. In this way, a positive electrode or a negative electrode of a lithium-ion battery is formed.

[0022] The substrate 1 is a metal foil that will become a battery electrode plate for a lithium-ion battery, and aluminum foil or the like is used to form the positive electrode, and copper foil or the like is used to form the negative electrode. The substrate 1 is a strip-shaped sheet that is long in one direction, and is transported by the transport device 2 so that it passes through each part that constitutes the coating device 100.

[0023] The coating liquid 11 is, for example, a slurry in which an active material, a binder, and a conductive additive are mixed in a solvent, and is used as a material for a battery electrode plate (so-called electrode material) for a lithium-ion battery. The coating liquid 11 is applied to the substrate 1 through the slit die 3 to form a coating film.

[0024] The conveying device 2 is for continuously conveying the substrate 1 in the longitudinal direction of the substrate 1 by a roll-to-roll method. The conveying speed of the substrate 1 by this conveying device 2 is controlled by a general-purpose computer device (not shown). Note that in the example of FIG. 1, only the coating roll 21 that guides the substrate 1 to the position where the coating liquid 11 is applied is shown, but in reality, multiple rolls are provided, such as an unwinding roll that unwinds the substrate 1, a take-up roll that winds up the substrate 1, and a conveying roll through which the substrate 1 unwound from the unwinding roll passes before being wound up onto the take-up roll.

[0025] The coating roll 21 has a cylindrical shape and rotates around the central axis of the cylinder. The coating roll 21 is disposed opposite the slit die 3 and supports the substrate 1 from the back side of the substrate 1 at a predetermined embrace angle. This allows the substrate 1 to be transported while maintaining a constant distance from the slit die 3.

[0026] The slit die 3 is used to apply the coating liquid 11 to the surface of the substrate 1, which is continuously transported by the transport device 2, to form a coating film. The slit die 3 is formed long along the width direction (the Y-axis direction shown in FIG. 1 ) perpendicular to the transport direction of the substrate 1 in the in-plane direction of the substrate 1. The coating roll 21 described above is disposed at a predetermined distance from the slit die 3 so that the rotational axis direction of the coating roll 21 and the longitudinal direction of the slit die 3 are parallel. That is, the coating liquid 11 is applied from the slit die 3 to the surface of the substrate 1 while the distance between the guided substrate 1 and the discharge opening 33 of the slit die 3 is maintained constant by the coating roll 21. The longitudinal direction of the slit die 3 and the width direction of the substrate 1 are the same, and will be referred to as the width direction in the following description.

[0027] As shown in Figures 1 to 3, the slit die 3 includes a manifold 31 formed to be long in the width direction and storing the coating liquid 11, a discharge port 33 connected to the manifold 31 via a slit 32 and discharging the coating liquid 11, and a shim 34 that determines the dimension of the slit 32 in the longitudinal direction of the manifold 31.

[0028] Specifically, the slit die 3 is configured by combining a first divided body 3a having a tapered first lip 35 and groove 36 formed therein, and a second divided body 3b having a tapered second lip 37 and groove 38 formed therein, with a generally U-shaped shim 34 sandwiched between them and comprising a main body 34a, protruding pieces 34b, and protruding pieces 34c. A manifold 31 and a slit 32 are formed therein, and a discharge port 33 is formed between the first lip 35 and the second lip 37. In this embodiment, the manifold 31 is formed by the main body 34a, protruding pieces 34b, and protruding pieces 34c of the shim 34 and the groove 38. The discharge port 33 opens to the same length in the width direction as the slit 32.

[0029] The slit 32 is formed to be long in the width direction, similar to the manifold 31, and its dimension in the width direction is determined by a shim 34. Specifically, as shown in Fig. 3, the dimension of the slit 32 in the width direction is determined by an inner dimension W of the shim 34 in the width direction, and the coating liquid 11 having a width dimension substantially the same as the width dimension of the slit 32 is applied to the surface of the substrate 1. Then, by replacing the shim 34 sandwiched between the first divided body 3a and the second divided body 3b with a shim 34 having an inner dimension different from that of the shim 34, the width dimension of the coating liquid 11 applied to the surface of the substrate 1 (hereinafter, coating width) can be changed.

[0030] The supply mechanism 4 is for supplying the coating liquid 11 to the slit die 3. As shown in Fig. 1, the supply mechanism 4 has a tank 41 that stores the coating liquid 11, a supply path 42 that connects the slit die 3 and the tank 41, and a pump (not shown) that delivers the coating liquid 11. The supply path 42 is connected to the center of the bottom of the manifold 31. That is, the coating liquid 11 delivered by the pump from the tank 41 through the supply path 42 is supplied to the manifold 31, passes through the slit 32, and is delivered from the discharge port 33.

[0031] With these configurations, the coating device 1 can apply the coating liquid 11 from the slit die 3 to a predetermined coating width onto the surface of the substrate 1 that is continuously transported by the transport device 2, thereby forming a coating film.

[0032] 1 to 3, the slit die 3 includes a block portion 51 that adjusts the volume of the manifold 31 by being inserted into or removed from the manifold 31. Here, a storage portion 39 that stores the block portion 51 when the block portion 51 is removed from the manifold 31 is formed inside the slit die 3. In this embodiment, the storage portion 39 is formed by a groove 36 formed in the first divided body 3a. That is, the volume of the manifold 31 is adjusted by inserting or removing the block portion 51 between the manifold 31 and the storage portion 39.

[0033] 2, block portions 51a to 51p are arranged inside the slit die 3. The volume of the manifold 31 can be adjusted across the width by inserting or removing each of the block portions 51a to 51p into or from the manifold 31. In the following description, when there is no need to distinguish between the block portions 51a to 51p, they will simply be referred to as block portion 51.

[0034] Here, each of the block portions 51 is inserted into and removed from the manifold 31 according to the dimension of the slit 32 in the width direction, which is determined by the shim 34. This allows the volume of the manifold 31 to be adjusted according to the dimension of the slit 32 in the width direction, making it possible to prevent particles such as the active material contained in the coating liquid 11 (hereinafter referred to as particles) from settling in the manifold 31.

[0035] Specifically, when the shim 34 is replaced to change the coating width, the dimension of the slit 31 in the width direction, as determined by the shim 34, may become smaller than the dimension of the manifold 31 in the width direction. In this case, a portion of the manifold 31 extending in the width direction beyond the slit 32 is formed, i.e., a retention portion S (see FIG. 7(b)) where the flow of the coating liquid 11 slows down and the coating liquid 11 stagnates. In this retention portion S, particles contained in the coating liquid 11 may settle. In order to prevent the settling of particles in the manifold 31, it is necessary to narrow the retention portion S. In contrast, in this embodiment, by inserting and removing each of the block portions 51 into and from the manifold 51, the volume of the manifold 31 can be adjusted according to the dimension of the slit 32 in the width direction, and therefore the retention portion S can be narrowed. Therefore, settling of particles contained in the coating liquid 11 in the manifold 31 can be prevented.

[0036] Furthermore, the cross section of the block portion 51 in the width direction has substantially the same shape as the cross section of the manifold 31 in the width direction, and the block portion 51 defines the end of the liquid storage region Q that stores the coating liquid 11 in the manifold 31. In other words, the liquid storage region Q is formed between the two block portions 51 inserted into the manifold 31.

[0037] Here, each block portion 51 is inserted into the manifold 31 so that the end of the liquid storage region Q in the width direction is positioned at the same position as the end of the slit 32 in the width direction. Specifically, as shown in FIGS. 2 and 3 , by inserting block portion 51a, block portion 51b, block portion 51o, and block portion 51p into the manifold 31, a liquid storage region Q is formed between block portion 51b and block portion 51o, whose end position in the width direction is positioned at the same position as the end of the slit 32 in the width direction. This makes it possible to eliminate the stagnation portion S. Therefore, it is possible to further suppress the settling of particles contained in the coating liquid 11 in the manifold 31.

[0038] Furthermore, the insertion amount of each block portion 51 into the manifold 31 can be individually adjusted. In this embodiment, the insertion amount of each block portion 51 into the manifold 31 is adjusted by an electric actuator 6. Specifically, as shown in FIGS. 1 to 3 , each block portion 51 is connected to an electric actuator 6 that moves the block portion 51 in and out of the manifold 31. The electric actuator 6 operates a shaft 61 connected to each block portion 51 in a direction in which the block portion 51 moves in and out between the manifold 31 and the storage portion 39, thereby individually adjusting the insertion amount into the manifold 31. This makes it possible to finely adjust the volume of the manifold 31. The shaft 61 is inserted into the storage portion 39 through the wall portion of the first divided body 3a, and a ring-shaped packing (not shown) is attached to the outer periphery of the shaft 61 to prevent the coating liquid 11 from leaking from the side wall portion of the first divided body 3a.

[0039] 1 and 2, the slit die 3 is provided with an exhaust path 71 for exhausting air present in the manifold 31. The exhaust path 71 is connected to the upper part of the storage section 39, and is capable of exhausting to the outside air that has moved from the manifold 31 to the upper part of the storage section 39 due to buoyancy. The air referred to here refers to air that enters through a joint of the supply path 42, a pump, etc.

[0040] In this embodiment, as shown in FIGS. 1 and 2 , the manifold 31 is located below the storage section 39 in the vertical direction (the Z-axis direction shown in FIGS. 1 and 2 ), which prevents poor application of the coating liquid 11 that may occur due to air stagnation in the manifold 31. Specifically, if the manifold 31 is located above the storage section 39 in the vertical direction and the exhaust path 71 is connected to the top of the manifold 31, the block section 51 may block the air flow path from the manifold 31 to the exhaust path 71, depending on the insertion state of the block section 51 into the manifold 31. In this case, air may stagnate in the manifold 31, which may result in poor application of the coating liquid 11. In contrast, in this embodiment, the manifold 31 is located below the storage section 39 in the vertical direction, which prevents air from stagnating in the manifold 31 because buoyancy causes air to move to the storage section 39 regardless of the insertion state of the manifold 31. Therefore, it is possible to prevent poor application of the coating liquid 11 that may occur due to air remaining in the manifold 31.

[0041] 1 and 3, a gap G is provided between the manifold 31 and the block portion 51 inserted into the manifold 31. That is, air present in the manifold 31 moves to the exhaust path 71 through the gap G. This allows the air present in the manifold 31 to be exhausted to the outside, regardless of the insertion state of each of the block portions 51 into the manifold 31.

[0042] As described above, according to the slit die 3 of the above embodiment, the volume of the manifold 31 can be adjusted according to the dimension of the slit 32 in the width direction by each of the multiple block portions 51, thereby narrowing the retention portion S. This makes it possible to suppress settling of particles contained in the coating liquid 11 in the manifold 31.

[0043] Furthermore, the slit die 3 in the above embodiment can accommodate various changes in coating conditions.

[0044] For example, this can also be used to adjust the thickness of the coating film formed on the surface of the substrate 1. Specifically, by adjusting the insertion amount of each block portion 51 into the manifold 31 and thereby adjusting the volume of the manifold 31, the amount of coating liquid 11 applied to the surface of the substrate 1 can be adjusted across the width. This allows the thickness of the coating film to be adjusted. For example, when adjusting the thickness of the coating film so that it becomes thicker from the ends toward the center in the width direction, as shown in FIG. 4, the insertion amount of each block portion 51 into the manifold 31 is adjusted so that it becomes thinner from the ends toward the center in the width direction. As a result, the volume of the manifold 31 increases from the ends toward the center in the width direction, so that the amount of coating liquid 11 applied to the surface of the substrate 1 increases from the ends toward the center in the width direction, and the thickness of the coating film becomes thicker from the ends toward the center in the width direction.

[0045] Here, the block portion 51 is inserted into and removed from the manifold 31 by an electric actuator 6. The electric actuator 6 has better controllability than other drive sources such as an air cylinder, and therefore can precisely adjust the amount of insertion of the block portion 51 into the manifold 31. This allows the volume of the manifold 31 to be precisely adjusted across the width, and therefore the thickness of the coating film to be precisely adjusted.

[0046] It is also possible to accommodate a case where a coating film is formed in a stripe pattern on the surface of the substrate 1. Specifically, as shown in Fig. 5(b), a protruding piece 34d is provided between protruding pieces 34b and 34c of the shim 34, and a plurality of slits 32 are provided so as to be arranged in the width direction, so that the coating liquid 11 is applied to the surface of the substrate 1 from each of the discharge outlets 33, which are the open ends of each of the slits 32, to form the coating film 11 in a stripe pattern. In this case, each of the block portions 51 is adapted to be inserted into and removed from the manifold 31 according to the dimensions of each of the slits 32 defined by the shim 34.

[0047] 5(a) and 5(b), block portion 51a, block portion 51b, block portion 51h, block portion i, block portion 51o, and block portion 51p are inserted into manifold 31 to form liquid storage regions Q and R corresponding to slits 32, respectively, and to make the positions of the ends of each slit 32 and the positions of the ends of liquid storage regions Q and R the same in the width direction. This makes it possible to narrow retention portion S generated in manifold 31, even when a plurality of slits 32 are provided so as to be aligned in the width direction, and therefore makes it possible to suppress settling of particles contained in coating liquid 11 in manifold 31.

[0048] 5(a) and 5(b), it is preferable to connect supply channel 11 to manifold 31 so as to supply coating liquid 11 to each of liquid storage region Q and liquid storage region R. In this case, it becomes possible to adjust the amount of coating liquid 11 supplied to each of liquid storage region Q and liquid storage region R by the pump, and therefore it is possible to accurately adjust the amount of coating liquid 11 discharged from each of discharge ports 33, which are the open ends of each of slits 32.

[0049] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible within the scope of the spirit of the present invention. For example, in the above embodiment, the slit die 3 is described as applying the coating liquid 11 to the front surface of the substrate 1, but the coating liquid 11 may also be applied to the back surface of the substrate 1.

[0050] In the above embodiment, the electric actuator 6 is used to move the block portion 51 in and out of the manifold 31, but the present invention is not limited to this. For example, an air cylinder may be used.

[0051] In the above embodiment, an example in which the gap G is formed inside the slit die 3 has been described, but it is not necessary to form the gap G. In addition, when the gap G is formed inside the slit die 3, the position at which the gap G is formed is not limited to the position shown in FIGS.

[0052] In the above embodiment, an example has been described in which the dimension of the slit 32 in the width direction is defined by the shim 34, but the dimension of the slit 32 in the width direction may be defined by a member other than the shim 34. In this case, the shim 34 does not need to be provided. [Explanation of symbols]

[0053] 100 Coating equipment 1 Base material 11 Coating liquid 2. Conveyor equipment 21 Coating roll 3 Slit Die 3a 1st division body 3b Second division body 31 Manifold 32 Slit 33 Discharge port 34 Sim 34a Main body 34b Projecting piece 34c protruding piece 34d protruding piece 35 First Lip 36 Groove 37 Second Lip 38 Groove 39 Storage section 4 Supply mechanism 41 Tank 42 Supply route 51 Block section 6 Electric Actuators 61 Shaft 71 Exhaust duct G Gap Q Liquid storage area R liquid storage area

Claims

1. a manifold formed long in one direction to store the coating liquid; a discharge port that is connected to the manifold via a slit and discharges a coating liquid, a block portion that is inserted into and removed from the manifold to adjust the volume of the manifold; The slit die is characterized in that the block portions are arranged in a row in the longitudinal direction of the manifold, and each of the block portions is inserted into or removed from the manifold according to the dimension of the slit in the longitudinal direction.

2. 2. The slit die according to claim 1, wherein a cross section of the block portion in the longitudinal direction has substantially the same shape as a cross section of the manifold in the longitudinal direction, and the block portion defines an end of a liquid storage region in the manifold that stores the coating liquid.

3. 3. The slit die according to claim 1, wherein the amount of insertion of each of the block portions into the manifold is individually adjustable.

4. 4. The slit die according to claim 3, wherein each of the block portions is connected to an electric actuator that moves the block portion in and out of the manifold.

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