coating device

Abstract

The objective is to provide a coating apparatus that can suppress the formation of drag of the coating liquid at the end of the coating film. [Solution] A coating apparatus comprising a die having a discharge port for discharging a coating liquid toward a predetermined surface of a conveyed substrate, and a supply valve that can be switched between an open state for supplying a coating liquid to the die and a closed state for stopping the supply of a coating liquid to the die, wherein the coating apparatus intermittently supplies and discharges a coating liquid to the die by switching the open and closed state of the supply valve, thereby intermittently forming a coating film on the predetermined surface of the substrate, further comprising a discharge volume adjustment mechanism for adjusting the amount of coating liquid discharged from the discharge port, wherein the discharge volume adjustment mechanism is configured to adjust the amount of coating liquid discharged from the discharge port to be small before switching the supply valve from the open state to the closed state.

Description

Technical Field

[0001] The present invention relates to a coating apparatus for forming a coating film by applying a coating liquid to a substrate.

Background Art

[0002] In a lithium-ion battery, a slurry of an electrode material (hereinafter referred to as a coating liquid) is applied to a sheet-like substrate such as an aluminum foil or a copper foil that is conveyed in a roll-to-roll manner to form a coating film, and the formed coating film is dried to form a positive electrode and a negative electrode.

[0003] And, in the manufacturing process of a lithium-ion battery, in order to increase the speed for productivity improvement and reduce the loss of the coating liquid, as shown in FIG. 5, a coating film 911 is intermittently formed on a predetermined surface of a substrate 910. That is, by repeatedly discharging and interrupting the discharge of the coating liquid with respect to a predetermined surface of the substrate 910 being conveyed, the coating film 911 is continuously formed on the predetermined surface of the substrate 910 so that there is a certain interval between each of the coating films 911 in the conveyance direction of the substrate 910.

[0004] Such a coating apparatus used in the manufacturing process of a lithium-ion battery, as shown in FIG. 5, includes a die 920 having a discharge port 921 for discharging a coating liquid, and a supply mechanism 930 for supplying the coating liquid to the die 920. By supplying the coating liquid to the die 920 by the supply mechanism 930, the coating liquid is discharged from the discharge port 921 toward a predetermined surface of the substrate 910.

[0005] Further, the supply mechanism 930 includes a tank 931 for storing the coating liquid, a supply path 932 connecting the tank 931 and the die 920, and a supply valve 933 that can be switched between an open state in which the supply path 932 is opened and a closed state in which the supply path 932 is closed. And, by switching the open / closed state of the supply valve 933, the supply of the coating liquid to the die 920 and the stop of the supply are repeated, so that the coating liquid is intermittently discharged from the discharge port 921 toward a predetermined surface of the substrate 910 to intermittently form the coating film 911 (for example, Patent Document 1 below).

Prior Art Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-188449 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, with the above coating apparatus 900, there were cases where drag of the coating liquid was formed at the end of the coating film.

[0008] Specifically, in the coating apparatus 900, the supply of coating liquid to the die 920 is stopped by switching the supply valve 933 from an open state to a closed state, and the pressure inside the die 920 is reduced, causing the coating liquid to be drawn back upstream from the discharge port 921. This is how the coating liquid is drained from the discharge port 921. However, in the coating apparatus 900, a constant amount of coating liquid 11 is continuously supplied to the die 920 until the supply valve 933 is switched from an open state to a closed state. Therefore, even if the supply valve 43 is switched from an open state to a closed state, it is not possible to immediately draw back a sufficient amount of coating liquid upstream from the discharge port 921 to drain the coating liquid from the discharge port 921, resulting in insufficient draining of the coating liquid at the discharge port 921. As a result, as shown in Figures 6(a) and 6(b), there was a problem in which a trail of coating liquid 913, which causes a short circuit in the lithium-ion battery, is formed at the coating end portion 912, which is the end of the coating film 911.

[0009] This invention has been made in view of the above-mentioned problems, and aims to provide a coating apparatus that can suppress the formation of drag of the coating liquid at the end of the coating film. [Means for solving the problem]

[0010] The present invention, which solves the above problems, comprises a die having a discharge port for discharging a coating liquid toward a predetermined surface of a conveyed substrate, and a supply valve that can be switched between an open state for supplying a coating liquid to the die and a closed state for stopping the supply of a coating liquid to the die, wherein the coating apparatus intermittently supplies and discharges a coating liquid to the die by switching the open and closed state of the supply valve, thereby intermittently forming a coating film on the predetermined surface of the substrate, and further comprises a discharge volume adjustment mechanism for adjusting the amount of coating liquid discharged from the discharge port, wherein the discharge volume adjustment mechanism adjusts the amount of coating liquid discharged from the discharge port to be small before switching the supply valve from the open state to the closed state.

[0011] According to the above coating apparatus, the discharge volume adjustment mechanism adjusts the amount of coating liquid discharged from the discharge port to be reduced before switching the supply valve from the open state to the closed state. Therefore, when switching the supply valve from the open state to the closed state to drain the coating liquid at the discharge port, the amount of coating liquid that needs to be pulled back upstream from the discharge port can be reduced. This prevents insufficient draining of the coating liquid at the discharge port. Consequently, the formation of coating liquid trails at the end of the coating film can be suppressed.

[0012] Furthermore, the discharge volume adjustment mechanism may have a suck-back mechanism that pulls the coating liquid back upstream from the discharge port, and the suck-back mechanism may be configured to reduce the amount of coating liquid discharged from the discharge port by starting to pull the coating liquid back upstream from the discharge port before switching the supply valve from the open state to the closed state.

[0013] With this configuration, the suck-back mechanism can reduce the amount of coating liquid discharged from the outlet by drawing it back upstream from the outlet. Furthermore, by starting the draw-back of the coating liquid upstream from the outlet before switching the supply valve from the open to the closed state, the amount of coating liquid that needs to be drawn back upstream from the outlet when switching the supply valve from the open to the closed state to drain the coating liquid at the outlet can be reduced.

[0014] Furthermore, the die has a coating channel formed therein that is connected to the discharge port and supplies the coating liquid to the discharge port, and the suck-back mechanism has a suck-back part inserted into the coating channel and a drive unit that moves the suck-back part in and out of the coating channel, and the drive unit may be configured to move the suck-back part out of the coating channel at a first speed before switching the supply valve from the open state to the closed state, and to move the suck-back part out of the coating channel at a second speed faster than the first speed when switching the supply valve from the open state to the closed state.

[0015] With this configuration, the suck-back mechanism adjusts the pressure inside the die and thus the amount of coating liquid discharged from the discharge port by moving the suck-back section, which is inserted into the coating channel by the drive unit, in and out of the coating channel. The drive unit moves the suck-back section out of the coating channel at a first speed before switching the supply valve from the open to the closed state, thereby drawing the coating liquid back into the coating channel from the discharge port and adjusting the amount of coating liquid discharged from the discharge port to be reduced. At the same time, when switching the supply valve from the open to the closed state, the suck-back section is moved out of the coating channel at a second speed faster than the first speed, thereby rapidly drawing the coating liquid back upstream from the discharge port and performing decoupling of the coating liquid at the discharge port. As a result, the amount of coating liquid that needs to be drawn back upstream from the discharge port when decoupling the coating liquid at the discharge port can be reduced, and because the coating liquid can be rapidly drawn back upstream from the discharge port at a position closer to the discharge port than the supply valve, insufficient decoupling of the coating liquid at the discharge port can be further suppressed.

[0016] Furthermore, the coating channel may have a pair of enlarged spaces formed to protrude in the width direction, and the suck-back portion may be configured to be inserted into each of the pair of enlarged spaces.

[0017] This configuration allows the coating liquid to be drawn back from the discharge port towards each of the pair of enlarged spaces formed to protrude in the width direction. As a result, the amount of coating liquid discharged from the discharge port can be adjusted across the width direction, thereby suppressing the formation of coating liquid trail at the end of the coating film across the width direction.

[0018] Furthermore, the coating channel may be configured to include a manifold, which is a space for storing coating liquid that is long in the width direction, and a slit connecting the manifold and the discharge port, and the pair of enlarged spaces may be formed to protrude from each of the ends of the manifold in the width direction.

[0019] According to this configuration, since the enlarged space is formed to protrude from a manifold wider than the slit, it is less likely to inhibit the flow of the coating liquid than forming the enlarged space in the slit.

Advantages of the Invention

[0020] According to the coating device of the present invention, it is possible to suppress the formation of dragging of the coating liquid at the end portion of the coating film.

Brief Description of the Drawings

[0021] [Figure 1] It is a diagram schematically showing a coating device in an embodiment of the present invention, showing a state in which a coating liquid is being discharged. [Figure 2] It is a diagram schematically showing a coating device in an embodiment of the present invention, showing a state in which the discharge of the coating liquid is interrupted. [Figure 3] It is a diagram for explaining a sack-back mechanism in an embodiment of the present invention, where (a) shows a cross-sectional view taken along the line A-A of FIG. 1, and (b) shows a cross-sectional view taken along the line B-B of FIG. 2. [Figure 4] It is a diagram for explaining the discharge operation of the coating liquid of a coating device in an embodiment of the present invention, where (a) shows a time chart of the operations of the supply valve, the recovery valve, and the sack-back portion, and (b) and (c) show the coating films formed by the coating device. [Figure 5] It is a diagram showing a conventional coating device. [Figure 6] It is a diagram showing a coating film formed by a conventional coating device.

Modes for Carrying Out the Invention

[0022] Embodiments of the coating device according to the present invention will be described with reference to the drawings. In the following description, the three axes of the orthogonal coordinate system are denoted as X, Y, and Z, the horizontal direction is expressed as the X-axis direction and the Y-axis direction, and the direction perpendicular to the XY plane (i.e., the vertical direction) is expressed as the Z-axis direction.

[0023] Figures 1 and 2 are schematic diagrams showing a coating apparatus 100 in one embodiment of the present invention, where Figure 1 shows the state in which the coating liquid 11 is being discharged, and Figure 2 shows the state in which the discharge of the coating liquid 11 is interrupted. Figure 3 is a diagram for explaining the suck-back mechanism 51 in one embodiment of the present invention, where (a) is a cross-section taken along the arrow AA in Figure 1, and (b) is a cross-section taken along the arrow BB in Figure 2. Figure 4 is a diagram for explaining the discharge operation of the coating liquid 11 of the coating apparatus 100 in one embodiment of the present invention, where (a) is a time chart showing the operation of the supply valve, the recovery valve, and the suck-back section, and (b) and (c) show the coating film 12 formed on a predetermined surface of the substrate 1 by the coating apparatus 100. Note that a to i in Figures 4(a) to 4(c) respectively indicate the respective states at the same time. Also, the dashed-dotted arrows in Figure 4(a) indicate the passage of time, and the solid arrows in Figures 4(b) and 4(c) indicate the direction in which the coating liquid 11 is applied to the substrate 1.

[0024] As shown in Figures 1 and 2, the coating apparatus 100 includes a transport mechanism 2 for transporting the substrate 1 and a coating mechanism 3 for applying a coating liquid 11 to a predetermined surface of the substrate 1. The coating mechanism 3 repeatedly applies the coating liquid 11 to the predetermined surface of the substrate 1 while it is being transported by the transport mechanism 2, and then interrupts the application process, thereby intermittently forming a coating film 12. Intermittent formation of the coating film 12 means that, as shown in Figure 1, the coating film 12 is continuously formed on the predetermined surface of the substrate 1 such that there is a certain gap between each coating film 12 formed in the transport direction of the substrate 1.

[0025] The base material 1 is a metal foil that will serve as the electrode plate for a lithium-ion battery. When forming the positive electrode, aluminum foil or the like is used, and when forming the negative electrode, copper foil or the like is used. This base material 1 is a long, strip-shaped sheet and is transported by the transport mechanism 2 so that it passes through each part that makes up the coating apparatus 100.

[0026] The coating liquid 11 is, for example, a slurry obtained by mixing an active material, a binder, and a conductive additive with a solvent, and is used as the material for the electrode plates of a lithium-ion battery (so-called electrode material). When this coating liquid 11 is applied to the substrate 1 by the coating mechanism 3, a coating film 12 is formed. This forms the positive or negative electrode of the lithium-ion battery.

[0027] The transport mechanism 2 is for transporting the substrate 1 and employs a roll-to-roll system in which the substrate 1 is transported by the rotation of multiple rolls. The transport speed of the substrate 1 by this transport mechanism 2 is controlled by a control unit (not shown). This control unit is, for example, a general-purpose computer, and will be treated similarly in the following description. In this embodiment, only the coating roll 21 that guides the substrate 1 to the location where the coating liquid 11 is applied by the coating mechanism 3 is shown. This coating roll 21 is positioned opposite the discharge port 32 of the die 31 of the coating mechanism 3 and holds the substrate 1 from the back side of a predetermined surface of the substrate 1 with a predetermined gripping angle. This allows the substrate 1 to be transported while maintaining a constant distance from the discharge port 32 of the die 31.

[0028] The coating mechanism 3 is for intermittently forming a coating film 12 by intermittently applying the coating liquid 11 to a predetermined surface of the substrate 1 being transported by the transport mechanism 2. This coating mechanism 3 includes a die 31 for dispensing the coating liquid 11 and a supply mechanism 4 for supplying the coating liquid 11 to the die 31.

[0029] The die 31 is formed to be elongated in one direction, and is elongated along the width direction (Y-axis direction shown in Figure 1) which is perpendicular to the transport direction of the substrate 1 in the in-plane direction of the substrate 1. The coating roll 21 is positioned such that the rotation axis direction of the coating roll 21 and the longitudinal direction of the die 31 are parallel to the die 31. In the following description, the width direction which is perpendicular to the transport direction of the substrate 1 in the in-plane direction of the substrate 1 will also be referred to as the width direction in the description of the die 31, etc.

[0030] The die 31 has a discharge port 32 for discharging the coating liquid 11 onto a predetermined surface of the substrate 1, a manifold 33 that is long in the width direction and stores the coating liquid 11, and a slit 34 connecting the discharge port 32 and the manifold 33. Specifically, the die 31 is constructed by combining a first divided body 31a, which has a tapered upstream lip 35 and a groove, and a second divided body 31b, which has a tapered downstream lip 36 and a groove, with a shim 37 in between them. The manifold 33 and the slit 34 are formed inside, and the discharge port 32 is formed between the upstream lip 35 and the downstream lip 36. The discharge port 32 opens to the same length as the slit 34 in the width direction.

[0031] Furthermore, an inlet port 38 is provided in the center of the die 31 in the width direction. The inlet port 38 is a through-hole connecting the outside of the die 31 to the manifold 33, and the coating liquid 11 is supplied to the manifold 33 through this inlet port 38. The coating liquid 11 supplied to the manifold 33 is then discharged from the discharge port 32 through the slit 34.

[0032] The supply mechanism 4 is for supplying the coating liquid 11 to the die 31. This supply mechanism 4 includes a tank 41 for storing the coating liquid 11, a supply passage 42 connecting the manifold 33 and the tank 41, a supply valve 43 that can be switched between an open state for supplying the coating liquid 11 to the die 31 and a closed state for stopping the supply of the coating liquid 11 to the die 31, a recovery passage 44 connecting the supply passage 42 and the tank 41, a recovery valve 45 that can be switched between an open state for recovering the coating liquid 11 into the tank 41 and a closed state for stopping the recovery of the coating liquid 11 into the tank 41, and a pump (not shown) for sending the coating liquid 11 from the tank 41 toward the die 31.

[0033] The supply channel 42 is a pipe connecting the die 31 and the tank 41, and is connected to the inlet port 38. In other words, the coating liquid 11 pumped from the tank 41 is supplied to the manifold 33 through the supply channel 42 and the inlet port 38.

[0034] The supply valve 43 is a valve that can be switched between an open state, which supplies the coating liquid 11 to the die 31, and a closed state, which stops the supply of the coating liquid 11 to the die 31, and is installed in the middle of the supply passage 42. In other words, the open and closed state is switched by opening and closing the supply passage 42 with the supply valve 43.

[0035] Specifically, the supply valve 43 contains a valve body 43c connected by a shaft 43b to a valve body drive unit 43a (for example, an electric motor or air cylinder), which is the drive source. The valve body drive unit 43a moves the shaft 43b, causing the valve body 43c to open or close the supply passage 42. As a result, as shown in Figure 1, opening the supply passage 42 switches to an open state, supplying the coating liquid 11 to the die 31, and as shown in Figure 2, closing the supply passage 42 switches to a closed state, stopping the supply of the coating liquid 11 to the die 31. The valve body drive unit 43a is controlled by the control unit mentioned above.

[0036] The control unit repeatedly switches the open and closed state of the supply valve 43, thereby intermittently supplying the coating liquid 11 to the die 31 and discharging it from the discharge port 32, and intermittently applying it to a predetermined surface of the substrate 1 being transported by the transport mechanism 2. This allows for the intermittent formation of a coating film 12 on the predetermined surface of the substrate 1.

[0037] The recovery channel 44 is a pipe connecting the tank 41 and the supply channel 42, and is connected to the supply channel 42 via a recovery valve 45 upstream of the supply valve 43. In other words, the coating liquid 11 flowing through the supply channel 42 flows through the recovery valve 45 to the recovery channel 44 and is recovered into the tank 41 through the recovery channel 44.

[0038] The recovery valve 45 is a valve that can be switched between an open state, which allows the coating liquid 11 to be recovered into the tank 41, and a closed state, which stops the recovery of the coating liquid 11 to the tank 41, and is installed between the supply passage 42 and the recovery passage 44. In other words, the open and closed state is switched by opening and closing the passage between the supply passage 42 and the recovery passage 44 using the recovery valve 45.

[0039] Specifically, the recovery valve 45 contains a valve body 45c connected by a shaft 45b to a valve body drive unit 45a (for example, an electric motor or air cylinder), which is the drive source. The valve body drive unit 45a moves the shaft 45b, causing the valve body 45c to open and close the passage between the supply passage 42 and the recovery passage 44. As shown in Figure 2, opening the passage between the supply passage 42 and the recovery passage 44 switches to an open state, allowing the coating liquid 11 to be collected in the tank 41. Closing the passage between the supply passage 42 and the recovery passage 44 switches to a closed state, stopping the collection of the coating liquid 11 into the tank 41, as shown in Figure 1. The valve body drive unit 45a is controlled by the control unit mentioned above.

[0040] Furthermore, as shown in Figure 4(a), the supply mechanism 4 switches the open / closed state of the recovery valve 45 in conjunction with the switch on the open / closed state of the supply valve 43. Specifically, as shown in Figures 1 and 2, when the supply valve 43 opens the supply passage 42, the recovery valve 45 closes the space between the supply passage 42 and the recovery passage 44, and when the supply valve 43 closes the supply passage 42, the recovery valve 45 opens the space between the supply passage 42 and the recovery passage 44. As a result, when switching the supply valve 43 from the open state to the closed state, the coating liquid 11 in the supply passage 42 located upstream of the supply valve 43 can be recovered into the tank 41 through the recovery passage 44. This prevents the pressure in the supply passage 42 located upstream of the supply valve 43 from increasing, and prevents the coating liquid 11 from being excessively supplied to the die 31 when switching the supply valve 43 from the closed state to the open state.

[0041] Furthermore, the supply mechanism 4 reduces the pressure inside the die 31 by moving the valve body 43c by the valve body drive unit 43a when switching the supply valve 43 from the open state to the closed state, thereby drawing the coating liquid 11 back from the discharge port 32 towards the supply passage 42. This ensures that the coating liquid 11 is drained from the discharge port 32.

[0042] Here, the coating device 100 is further equipped with a discharge volume adjustment mechanism 5 that adjusts the amount of coating liquid 11 discharged from the discharge port 32. This discharge volume adjustment mechanism 5 adjusts the amount of coating liquid 11 discharged from the discharge port 32 to be reduced before switching the supply valve 43 from the open state to the closed state. In other words, before switching the supply valve 43 from the open state to the closed state to drain the coating liquid 11 from the discharge port 32, the coating device 100 adjusts the amount of coating liquid 11 discharged from the discharge port 32 to be reduced by the discharge volume adjustment mechanism 5, thereby reducing the amount of coating liquid 11 that needs to be drawn upstream from the discharge port 32 when draining the coating liquid 11 from the discharge port 32.

[0043] Furthermore, the discharge volume adjustment mechanism 5 in this embodiment has a suck-back mechanism 51 that pulls the coating liquid 11 back upstream from the discharge port 32. The suck-back mechanism 51 adjusts the discharge volume of the coating liquid 11 from the discharge port 32 by changing the volume of the coating flow path and adjusting the pressure inside the die 31. The coating flow path, as used here, is a flow path for supplying the coating liquid 11 to the discharge port 32 formed in the die 31. In this embodiment, an example of changing the volume of the manifold 33 by the suck-back mechanism 51 will be described.

[0044] As shown in Figures 3(a) and 3(b), the suck-back mechanism 51 includes a pair of suck-back sections 52 inserted from each end of the manifold 33 in the width direction, and a drive unit 53 that moves each of the pair of suck-back sections 52 in and out of the manifold 33. Here, the manifold 33 has a pair of enlarged spaces 39 formed to protrude in the width direction from each end of the discharge port 32 in the width direction, and each of the pair of suck-back sections 52 is inserted into each of these enlarged spaces 39. The drive unit 53 moves the pair of suck-back sections 52 in and out of each of the enlarged spaces 39, thereby changing the volume of the manifold 33 to adjust the pressure inside the die 31 and adjust the amount of coating liquid 11 discharged from the discharge port 32.

[0045] The suckback portion 52 has a rod-shaped shaft portion 54 that is formed to be long in one direction, and a resistance portion 55 provided at the tip of the shaft portion 54, and is inserted into the enlarged space 39 from the end of the die 31 in the width direction. Specifically, each of the shaft portions 54 of the pair of suckback portions 52 is inserted into each of the pair of enlarged spaces 39 so as to extend from each of the walls at both ends of the die 31 in the width direction toward the other wall, and the resistance portion 55 is provided at the tip of the shaft portion 54 inserted into the enlarged space 39.

[0046] The resistance portion 55 is composed of a disc portion 55a and a cone portion 55b. The disc portion 55a is formed such that its cross-sectional area in the width direction is larger than the cross-sectional area in the width direction of the shaft portion 54, and is approximately the same size as the cross-sectional area in the width direction of the expansion space 39. Here, "approximately the same size" means that the resistance portion 55 can be moved by the drive unit 62, and that the coating liquid 11 does not leak out to the wall side of the expansion space 39 into which the shaft portion 54 is inserted when the resistance portion 55 moves. The cone portion 55b is formed such that its cross-sectional area in the width direction decreases as it moves in the direction in which the suck-back portion 52 is pushed into the expansion space 39.

[0047] The drive unit 53 is a drive source (for example, an electric motor) for moving the suck-back section 52 in and out of the manifold 33. This drive unit 53 is connected to the suck-back section 52, and by causing the suck-back section 52 to reciprocate in the longitudinal direction of the shaft section 54, the volume of the manifold 33 is changed.

[0048] Specifically, the drive unit 53 moves the suck-back section 52 out of the expanded space 39, thereby increasing the volume of the manifold 33 and reducing the pressure inside the die 31. The drive unit 53 also moves the suck-back section 52 into the expanded space 39, thereby decreasing the volume of the manifold 33 and increasing the pressure inside the die 31. When the pressure inside the die 31 is reduced, the coating liquid 11 is pulled back upstream from the discharge port 32, reducing the amount of coating liquid 11 discharged from the discharge port 32. When the pressure inside the die 31 is increased, the coating liquid 11 is pushed out of the discharge port 32, increasing the amount of coating liquid 11 discharged from the discharge port 32.

[0049] When the drive unit 53 moves the suck-back portion 52 in the direction of pushing it into the expansion space 39, the suck-back portion 52 is moved so that the tip of the resistance portion 55 is at the same position as the end of the discharge port 32 in the width direction, as shown in Figure 3(a). This position of the suck-back portion 52 after this movement will be referred to as the first position in the following description. When the drive unit 53 moves the suck-back portion 52 in the direction of withdrawing it from the expansion space 39, the suck-back portion 52 is moved so that it is withdrawn from the expansion space 39 while leaving the resistance portion 55 in the expansion space 39, as shown in Figure 3(b). This position of the suck-back portion 52 after this movement will be referred to as the second position in the following description.

[0050] Furthermore, the suck-back mechanism 51 is configured to start pulling back the coating liquid 11 from the discharge port 32 to the upstream side before switching the supply valve 43 from the open state to the closed state. Specifically, as shown in Figure 4(a), the suck-back mechanism 51 increases the volume of the manifold 33 and reduces the pressure inside the die 31 by initiating the movement of the suck-back section 52 from a first position to a second position by the drive unit 53 before switching the supply valve 43 from the open state to the closed state, thereby pulling back the coating liquid 11 from the discharge port 32 to the upstream side. This reduces the amount of coating liquid 11 discharged from the discharge port 32 before switching the supply valve 43 from the open state to the closed state to drain the coating liquid 11 from the discharge port 32, and reduces the amount of coating liquid 11 that needs to be pulled back from the discharge port 32 to the upstream side when draining the coating liquid 11 from the discharge port 32.

[0051] Furthermore, in this embodiment, the suck-back mechanism 51 is configured such that, before the supply valve 43 is switched from the open state to the closed state, the drive unit 53 moves the suck-back section 52 out of the expansion space 3 at a first speed, and when the supply valve 43 is switched from the open state to the closed state, it moves the suck-back section 52 out of the expansion space 39 at a second speed faster than the first speed.

[0052] Specifically, as shown in Figure 4(a), the suck-back mechanism 51 moves the suck-back section 52 at a first speed to a third position located between the first and second positions by the drive unit 53 before the supply valve 43 is switched from the open to the closed position, thereby pulling the coating liquid 11 upstream from the discharge port 32 and reducing the amount of coating liquid 11 discharged from the discharge port 32. At the same time, when the supply valve 43 is switched from the open to the closed position, the suck-back section 52 is rapidly moved at a second speed from the third position to the second position, thereby rapidly pulling the coating liquid 11 upstream from the discharge port 32 and draining the coating liquid 11 from the discharge port 11.

[0053] Furthermore, in this embodiment, the enlarged space 39 is formed such that its cross-sectional area in the width direction is smaller than the cross-sectional area of ​​the manifold 33. Specifically, as shown in Figures 1 and 2, the enlarged space 39 is formed only in the first segment 31a among the first segment 31a, the second segment 31b, and the shim 37 that form the manifold 33, thereby making the cross-sectional area in the width direction smaller than the cross-sectional area of ​​the manifold 33. In this way, since the enlarged space 39 is formed only in the first segment 31a, even if the components of the die 31 other than the first segment 31a are changed, such as by changing the shim 37, the size and shape of the enlarged space 39 will not change.

[0054] The operation of the coating apparatus 100 in this embodiment will be described below.

[0055] In the following explanation, we will start from a state where the supply mechanism 4 is not supplying the coating liquid 11 to the die 31, as shown in Figure 4(a), and the die 31 is not discharging the coating liquid 11. That is, we will start from a state where the supply valve 43 is closed and the recovery valve 45 is open, as shown in Figure 2. We will assume that the pump is continuously supplying the coating liquid 11 from the tank 41 to the die 31 until the discharge of the coating liquid 11 from the die 31 is completely stopped.

[0056] First, the operation when the discharge of the coating liquid 11 from the die 31 is started will be explained. As shown in Figures 1 and 4(a), the supply mechanism 4 supplies the coating liquid 11 from the tank 41 to the manifold 33 through the supply passage 42 by switching the supply valve 43 from a closed state to an open state and switching the recovery valve 45 from an open state to a closed state. The coating liquid 11 supplied to the manifold 33 is then discharged from the discharge port 32 through the slit 34. As a result, as shown in Figures 4(b) and 4(c), the starting end 13 of the coating film 12 is formed on a predetermined surface of the substrate 1 being transported by the transport mechanism 2. This series of operations when the discharge of the coating liquid 11 from the die 31 is started is also performed when the discharge of the coating liquid 11 is interrupted and then resumed.

[0057] When the discharge of the coating liquid 11 from the die 31 is started, the pair of suck-back sections 52 are in the first position, as shown in Figures 3(a) and 4(a).

[0058] Then, the coating device 100 continues to discharge the coating liquid 11 from the die 31 while maintaining the open and closed states of the supply valve 43 and the recovery valve 45, thereby applying the coating liquid 11 to a predetermined surface of the substrate 1 being transported by the transport mechanism 2, as shown in Figures 4(b) and 4(c), to form a coating film 12.

[0059] Next, the operation when the discharge of the coating liquid 11 from the die 31 is interrupted will be explained. As shown in Figures 2 and 4(a), the supply mechanism 4 stops the supply of the coating liquid 11 to the manifold 33 by switching the supply valve 43 from the open state to the closed state and the recovery valve 45 from the closed state to the open state, thereby interrupting the discharge of the coating liquid 11 from the die 31 and draining the coating liquid 11 at the discharge port 32.

[0060] Here, as shown in Figure 4(a), the suck-back mechanism 51 reduces the amount of coating liquid 11 discharged from the discharge port 32 by moving the suck-back section 52 from the first position to the third position at a first speed using the drive unit 53 before switching the supply valve 43 from the open state to the closed state, thereby drawing the coating liquid 11 upstream from the discharge port 32. Then, as shown in Figure 4(a), when switching the supply valve 43 from the open state to the closed state, the suck-back mechanism 51 rapidly moves the suck-back section 52 from the third position to the second position at a second speed using the drive unit 53, thereby rapidly drawing the coating liquid 11 upstream from the discharge port 32 and draining the coating liquid 11 at the discharge port 32.

[0061] As a result, a coating end portion 14 (see Figures 4(b) and 4(c)) is formed, which is the end portion of the coating film 12, where the dragging of the coating liquid 11 (dragging 913 shown in Figures 6(a) and 6(b)) is suppressed.

[0062] Specifically, in this embodiment, the suck-back mechanism 51 adjusts the discharge amount of the coating liquid 11 to be reduced before switching the supply valve 43 from the open state to the closed state, thereby reducing the amount of coating liquid 11 that should be drawn upstream from the discharge port 32 when draining the coating liquid 11 at the discharge port 32. As a result, it is possible to suppress insufficient draining of the coating liquid 11 compared to when draining the coating liquid 11 at the discharge port 32 without adjusting the discharge amount of the coating liquid 11 from the discharge port 32. Therefore, it is possible to suppress the formation of drag of the coating liquid 11 at the end portion 14 of the coating film.

[0063] On the other hand, in this embodiment, the amount of coating liquid 11 discharged from the discharge port 32 is reduced even before the supply valve 43 is switched from the open state to the closed state by the suck-back mechanism 51. This suppresses the formation of drag of the coating liquid 11 at the coating end portion 14, thereby preventing short circuits in lithium-ion batteries. However, as shown in Figures 4(b) and 4(c), the thickness of the coating film 12 near the coating end portion 14 becomes smaller. In contrast, the suck-back mechanism 51 in this embodiment adjusts the amount of coating liquid 11 discharged from the discharge port 32 so that the thickness of the coating film 12 in the range of 1 to 2 mm in front of the coating end portion 14 is about 30 to 70% of the thickness of the coating film 12 outside that range. This makes it possible to suppress the occurrence of drag of the coating liquid 11 at the coating end portion 14 without degrading the performance of the lithium-ion battery.

[0064] Furthermore, in this embodiment, when the suck-back mechanism 51 switches the supply valve 43 from the open state to the closed state, the coating liquid 11 is rapidly pulled back upstream from the discharge port 32 at a position closer to the discharge port 32 than the supply valve 53, thereby draining the coating liquid 11 from the discharge port 32. This makes it possible to further suppress insufficient draining of the coating liquid 11 from the discharge port 32 compared to when draining the coating liquid 11 from the discharge port 32 is performed only by switching the supply valve 43 from the open state to the closed state. Therefore, it is possible to further suppress the formation of drag of the coating liquid 11 at the end portion 14 of the coating film.

[0065] Next, we will explain the operation when resuming the discharge of the coating liquid 11 from the die 31. Note that, apart from the operation of the suck-back mechanism 51, the operation is the same as when starting the discharge of the coating liquid 11 from the die 31, so we will omit the explanation.

[0066] As shown in Figure 4(a), the suck-back mechanism 51 operates to push the suck-back portion 52 into the expanding space 39, returning it from the second position to the first position, when the supply valve 43 and the recovery valve 45 are operated. This restarts the discharge of the coating liquid 11 from the die 31, and the starting end portion 13 of the coating film is formed. Then, as shown in Figure 4(a), the coating device 100 repeats the above operation, allowing the coating film 11 to be intermittently formed on a predetermined surface of the substrate 1, as shown in Figures 4(b) and 4(c).

[0067] As described above, with the coating apparatus 100 in the above embodiment, the discharge volume adjustment mechanism 5 adjusts the discharge volume of the coating liquid 11 from the discharge port 32 to be reduced before switching the supply valve 43 from the open state to the closed state. This reduces the amount of coating liquid 11 that needs to be drawn upstream from the discharge port 32 when switching the supply valve 43 from the closed state to the open state to drain the coating liquid 11 from the discharge port 32. This prevents insufficient draining of the coating liquid 11 compared to when draining the coating liquid 11 from the discharge port 32 without adjusting the discharge volume of the coating liquid 11 from the discharge port 32. Therefore, it is possible to prevent the formation of drag of the coating liquid 11 at the coating end portion 14, which is the end portion of the coating film 12.

[0068] Furthermore, in the above embodiment, the drive unit 53 moves the suck-back section 52 out of the coating channel at a first speed before switching the supply valve 43 from the open state to the closed state, thereby drawing the coating liquid 11 back into the coating channel from the discharge port 32 and adjusting the amount of coating liquid 11 discharged from the discharge port 32 to be reduced. At the same time, when switching the supply valve 43 from the open state to the closed state, the drive unit 53 moves the suck-back section 52 out of the coating channel at a second speed faster than the first speed, thereby rapidly drawing the coating liquid 11 back upstream from the discharge port 32 and draining the coating liquid 11 at the discharge port 32. This reduces the amount of coating liquid 11 that needs to be drawn back upstream from the discharge port 32 when draining the coating liquid 11 at the discharge port 32. In addition, because the coating liquid 11 can be rapidly drawn back upstream from the discharge port at a position closer to the discharge port 32 than the supply valve 43, insufficient draining of the coating liquid 11 at the discharge port 32 can be further suppressed.

[0069] Furthermore, in the above embodiment, since the suck-back portion 52 is inserted into each of the pair of enlarged spaces 39 formed to protrude in the width direction, the amount of coating liquid 11 discharged from the discharge port 32 can be adjusted in the width direction by moving the suck-back portion 52 from the first position to the second position and drawing the coating liquid 11 back into each of the pair of enlarged spaces 39. This makes it possible to suppress the formation of drag of the coating liquid 11 at the coating film end portion 14 in the width direction.

[0070] Furthermore, in the above embodiment, a pair of expanding spaces 39 are formed to protrude from each of the ends in the width direction of the manifold 33, which is wider than the slit 34, and a suck-back portion 52 is inserted into each of the pair of expanding spaces 39. As a result, the flow of the coating liquid 11 is less likely to be obstructed by the suck-back portion 52 than if a pair of expanding spaces 39 were formed in the slit 34 and the suck-back portion 52 were inserted into them.

[0071] Furthermore, in the above embodiment, the resistance portion 55 is configured to include a conical portion 55b whose cross-sectional area in the width direction decreases as the suck-back portion 52 is pushed into the enlarged space 39. This reduces the resistance force on the coating liquid 11 when the suck-back portion 52 is moved in the direction of pushing into the enlarged space 39, thereby reducing the force that pushes the coating liquid 11 towards the discharge port 32. As a result, it is possible to suppress the over-application of the coating liquid 11 when the discharge of the coating liquid 11 from the discharge port 32 is restarted, and thus suppress the bulging of the coating film 12 at the starting end 13 of the coating film (bulging 915 in Figure 6(b)).

[0072] Although embodiments of the present invention have been described in detail above with reference to the drawings, the configurations and combinations thereof in the above embodiments are merely examples, and additions, omissions, substitutions, and other modifications to the configurations are possible without departing from the spirit of the present invention. For example, in the above embodiments, the discharge volume adjustment mechanism 5 has a suck-back mechanism 51, and the discharge volume of the coating liquid 11 from the die 31 has been described as being adjusted by the suck-back mechanism 51, but the invention is not limited to this. For example, a pipe for discharging the coating liquid 11 from the slit 34 and a valve capable of adjusting the flow rate of the coating liquid 11 discharging from the slit 34 through the pipe may be provided, and the discharge volume of the coating liquid 11 from the die 31 may be adjusted by discharging the coating liquid 11 from the slit 34 through the pipe while adjusting the flow rate of the coating liquid 11 with the valve. [Explanation of Symbols]

[0073] 100 Coating device 1 Base material 11. Application solution 12. Coating film 13. Starting point of the coating film 14 End portion of the coating 2. Conveying mechanism 21 Coating Roll 3. Coating mechanism 31 Die 31a 1st division body 31b Second division body 32 Discharge port 33 Manifold 34 slits 35 Upstream lip 36 Downstream lip 37 Sims 38 Inflow Ports 39. Expanded Space 4 Supply mechanism 41 tanks 42 Supply route 43 Supply valve 43a Valve body drive unit 43b shaft 43c Valve body 44 Recovery Route 45 Recovery valve 45a Valve body drive unit 45b shaft 45c valve body 5 Discharge amount adjustment mechanism 51 Suckback Mechanism 52 Sackback section 53 Drive unit 54 shafts 55 Resistance section 55a Disc section 55b Cone section

Claims

1. A die having a discharge port for dispensing a coating liquid toward a predetermined surface of a substrate being transported, The system includes a supply valve that can be switched between an open state for supplying coating liquid to the die and a closed state for stopping the supply of coating liquid to the die. A coating apparatus that intermittently supplies and discharges coating liquid to the die by switching the open / closed state of the supply valve, thereby intermittently forming a coating film on the predetermined surface of the substrate, The system further includes a discharge volume adjustment mechanism for adjusting the amount of coating liquid discharged from the aforementioned discharge port. The coating apparatus is characterized in that the discharge volume adjustment mechanism adjusts the amount of coating liquid discharged from the discharge port to be reduced before switching the supply valve from the open state to the closed state.

2. The aforementioned discharge volume adjustment mechanism has a suck-back mechanism that pulls the coating liquid back upstream from the discharge port. The coating apparatus according to claim 1, characterized in that the suck-back mechanism reduces the amount of coating liquid discharged from the discharge port by starting to pull the coating liquid back upstream from the discharge port before switching the supply valve from the open state to the closed state.

3. The die has a coating channel formed therein, which is connected to the discharge port and supplies the coating liquid to the discharge port. The suck-back mechanism comprises a suck-back portion inserted into the coating channel and a drive unit that moves the suck-back portion in and out of the coating channel. The coating apparatus according to claim 2, characterized in that the drive unit moves the suck-back portion out of the coating channel at a first speed before switching the supply valve from the open state to the closed state, and moves the suck-back portion out of the coating channel at a second speed faster than the first speed when switching the supply valve from the open state to the closed state.

4. The coating channel has a pair of enlarged spaces formed to protrude in the width direction, The coating apparatus according to claim 3, characterized in that the suckback portion is inserted into each of the pair of enlarged spaces.

5. The coating channel comprises a manifold, which is a space for storing coating liquid that is long in the width direction, and a slit connecting the manifold and the discharge port. The coating apparatus according to claim 4, characterized in that the pair of enlarged spaces are formed to protrude from each of the ends of the manifold in the width direction.

Images