Coating device

Abstract

To perform intermittent coating with preferable productivity while suppressing liquid sagging of a coating material generated at the time of intermittent coating.SOLUTION: In a coating device that performs intermittent coating on an object to be coated 10 with a coating material 9, an intermittent valve 5 includes: an inflow port 5a through which the coating material 9 flows in; an outflow port 5b through which the coating material 9 flows out; and a valve body 5c that opens and closes a part between the inflow port 5a and the outflow port 5b. The valve body 5c includes a through hole 5e that allows the coating material 9 to flow between the inflow port 5a and the outflow port 5b when the valve body 5c operates to open, the through hole 5e being formed to have a cross-sectional shape being a further flat shape than a cross-sectional shape of the inflow port 5a and a cross-sectional shape of the outflow port 5b. The valve body 5c switches between the open state and the closed state by operating to rotate within a rotation angle range in which a penetration direction of the through hole 5e forms less than 90 degrees, with, as a rotation axis, a straight line AL orthogonal to a flowing direction of the coating material 9 in the inflow port 5a and the outflow port 5b.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a coating device that intermittently applies a predetermined coating material. [Background technology]

[0002] Patent Document 1 describes a coating device that performs intermittent coating of ink. The coating device described in Patent Document 1 includes a coating head, a tank that stores ink to be supplied to the coating head and is located lower than the coating head, a switch valve that switches the ink from the tank to be supplied to the coating head during coating and to the tank when coating is interrupted, a first coating pipe that connects the tank to the switch valve, a second coating pipe that connects the switch valve to the coating head, one end of the first pipe connected to the switch valve, a second pipe that one end of the first pipe connected to an outlet above the coating head, connectors that connect the other end of the first pipe to the other end of the second pipe and are located at a height equal to or higher than the coating head, a third pipe that connects the connectors to the tank and is located lower than the connector, and a coating valve that is located midway along the second pipe and is closed during coating. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-171688 Summary of the Invention [Problem to be solved by the invention]

[0004] In the coating device described in Patent Document 1, so-called intermittent coating is performed by operating a switching valve and a coating valve (intermittent valve) to intermittently supply ink (coating material) to a coating head. Such intermittent coating manufacturing technology is used to manufacture battery electrodes. For example, a material (active material) for forming an electrode is intermittently coated onto a web-shaped current collector. The web material is then cut to remove the portion coated with the electrode active material (coating material), thereby forming a battery electrode (or electrode sheet). By utilizing such intermittent coating and web conveying technology, large quantities of battery electrodes can be manufactured with high productivity. However, when manufacturing electrodes using the above-mentioned intermittent coating, as shown in Figure 1, for example, the amount of coating material applied or the thickness of the coating film decreases at the end of the portion coated with the coating material on the substrate, resulting in so-called "sagging." This type of coating sagging can occur both when intermittent coating begins (when the coating valve opens) and when intermittent coating stops (when the coating valve closes) (Figure 1 shows an image of sagging occurring at the tip of the coated area when intermittent coating begins). In areas where sagging occurs, the energy density of the electrode decreases, which ultimately leads to a decrease in battery performance and quality.

[0005] This invention was devised with an eye on the above-mentioned technical problems, and aims to provide a coating device that can suppress the drooping of the coating material that occurs during intermittent coating and can carry out intermittent coating with high productivity. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention provides a coating device that includes a pump that sucks in and pressure-feeds a liquid coating material, a coating head that discharges the coating material pressure-fed from the pump toward a predetermined object to be coated, a flow path that causes the coating material to flow between the pump and the coating head, and an intermittent valve that is provided in the flow path and opens and closes to allow or block the flow of the coating material in the flow path, and that intermittently coats the object with the coating material, wherein the flow path has a first flow path that causes the coating material to flow between a discharge port of the pump and an inlet of the intermittent valve, and a second flow path that causes the coating material to flow between an outlet of the intermittent valve and the coating head, and the intermittent valve The coating material supplying device has an inlet connected to the first flow path and through which the coating material flows, an outlet connected to the second flow path and through which the coating material flows, and a valve body that opens and closes the gap between the inlet and the outlet, and when the valve body operates to the open state, it allows the coating material to flow between the inlet and the outlet, and has a through hole formed with a cross-sectional shape that is flatter than the cross-sectional shapes of the inlet and the outlet, and operates to rotate the through direction of the through hole within a rotation angle range of less than 90 degrees around a straight line perpendicular to the flow direction of the coating material at the inlet and the outlet as a rotation axis, thereby switching between the open state and the closed state. [Effects of the Invention]

[0007] In the coating device of the present invention, a coating material is intermittently applied by opening and closing an intermittent valve, i.e., intermittent coating is performed. The intermittent valve opens and closes by rotating a valve element having a through hole formed therein. In the coating device of the present invention, the cross-section of the flow path of the through hole in the valve element of the intermittent valve described above has a flatter cross-sectional shape compared to the cross-sectional shapes of the flow paths (and the inlet and outlet of the intermittent valve) before and after the through hole (upstream and downstream sides). Therefore, compared to conventional intermittent valves (coating valves) that open and close by rotating the valve element 90 degrees, such as ball valves and butterfly valves, the intermittent valve can be opened and closed by simply rotating the valve element by a small rotation angle of less than 90 degrees. For example, the intermittent valve can be opened and closed by simply rotating the valve element 45 degrees, half the rotation angle required in the conventional case. Being able to open and close the intermittent valve with a 45-degree rotation reduces the time required to open and close the intermittent valve (operating time or opening and closing time) by half compared to the conventional case where the valve element is rotated 90 degrees. As a result, it is possible to improve the work efficiency when performing intermittent coating and the productivity of products (e.g., battery electrodes) manufactured using intermittent coating. Furthermore, by shortening the operating time of the intermittent valve as described above, the time periods during which sagging of the coating material may occur when coating starts and stops during intermittent coating is also shortened. This makes it possible to suppress sagging of the coating material during intermittent coating. Ultimately, it is possible to improve the performance and quality of batteries manufactured using intermittent coating.

[0008] Therefore, the coating device of the present invention can suppress the drooping of the coating material that occurs during intermittent coating, and can carry out intermittent coating with good productivity. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram for explaining the problems with the conventional technology, showing the state in which sagging occurs at the end of the coating material when conventional intermittent coating is performed. [Figure 2] FIG. 2 is a diagram for explaining an outline of a coating device to which the present invention is applied. [Figure 3] FIG. 3 is a diagram showing an image of the structure and operation of a coating valve in a coating device to which the present invention is applied. [Figure 4] FIG. 4 is a diagram for explaining the problems of the conventional technology, showing an image of the structure and operation of a coating valve in a conventional coating device. [Figure 5] FIG. 5 is a diagram illustrating the effect of reducing sagging that occurs at the end of the coating material when intermittent coating is performed using a coating device to which the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are merely examples of specific embodiments of the present invention and are not intended to limit the scope of the present invention.

[0011] An outline (image) of a coating device according to an embodiment of the present invention is shown in Figure 2. The coating device 1 according to the embodiment of the present invention includes, as its main components, a tank 2, a pump 3, a flow path 4, a first intermittent valve 5, a second intermittent valve 6, a suck-back valve 7, and a coating head 8.

[0012] The tank 2 stores a predetermined coating material 9. The coating device 1 in this embodiment of the present invention discharges the liquid coating material 9 from a coating head 8 (described later) and applies (i.e., coats) the liquid coating material 9 to a predetermined object 10 to be coated. The coating material 9 is, for example, an "electrode active material" that is used as a material for "battery electrodes" (not shown), and is a liquid fluid with a predetermined fluidity. Such liquid coating material 9 is stored in the tank 2.

[0013] The pump 3 sucks the coating material 9 stored in the tank 2 and discharges it from the discharge port 3a. The discharge port 3a of the pump 3 is connected to a flow path 4, which will be described later. Therefore, the pump 3 pressure-feeds the coating material 9 sucked from the tank 2 into the flow path 4.

[0014] Flow path 4 allows the coating material 9 to flow between pump 3 and coating head 8 (described later). Flow path 4 is, for example, a "pipe" that pressure-feeds coating material 9. Flow path 4 is mainly composed of a first flow path 4a that allows the coating material 9 to flow between discharge port 3a of pump 3 and inlet 5a of first intermittent valve 5 (described later), a second flow path 4b that allows the coating material 9 to flow between outlet 5b of first intermittent valve 5 (described later) and coating head 8, and a third flow path 4c that allows the coating material 9 to flow between inlet 5a of first intermittent valve 5 (described later) and tank 2 via second intermittent valve 6 (described later).

[0015] The first intermittent valve 5 is a "switching valve" or "ON-OFF valve" that is provided midway through the flow path 4 and that opens and closes to allow or block the flow of the coating material 9 through the flow path 4. Therefore, the first intermittent valve 5 corresponds to the "intermittent valve" in this embodiment of the present invention. The first intermittent valve 5 mainly includes an inlet 5a connected to the first flow path 4a and through which the coating material 9 pumped from the pump 3 flows in; an outlet 5b connected to the second flow path and through which the coating material 9 pumped to the inlet 5a flows out toward the coating head 8 (described later); a valve element 5c that switches the inlet 5a and outlet 5b between an open and closed state; and a motor 5d that operates the valve element 5c to switch between the open and closed states. The specific shape and operation of the valve element 5c will be described later.

[0016] The second intermittent valve 6 is provided in the middle of the flow path 4, specifically in the middle of the third flow path 4c between the inlet 5a of the first intermittent valve 5 and the tank 2. The second intermittent valve 6 is a "switching valve" or "ON-OFF valve" that allows or blocks the flow of the coating material 9 in the third flow path 4c by opening and closing, and may have the same configuration as the first intermittent valve 5. For example, the second intermittent valve 6 is connected to the inlet 5a of the first intermittent valve 5 together with the above-mentioned first flow path 4a, and when the first intermittent valve 5 is switched to a closed state, the second intermittent valve 6 is composed of the inlet 6a through which the coating material 9 pressurized from the pump 3 flows in (backflows) through the third flow path 4c, the outlet 6b is connected to the return port 2a of the tank 2 and causes the coating material 9 pressurized to the inlet 6a to flow out toward the tank 2 (return to the tank 2), a valve body 6c that switches the inlet 6a and outlet 6b between an open and closed state, and a motor 6d that operates the valve body 6c to switch between the open and closed states as described above.

[0017] The suck-back valve 7 is provided in the flow path 4, specifically, in the second flow path 4b between the outlet 5b of the first intermittent valve 5 and a coating head 8 (described later). The suck-back valve 7 is, for example, a "switching valve" or "ON-OFF valve" that moves a cylindrical "piston" (valve body, not shown) back and forth. In the example shown in FIG. 2, the suck-back valve 7 moves (advances) the "piston" in a direction (to the right in FIG. 2) toward the coating head 8, thereby pressing the coating material 9 present in the second flow path 4b between the suck-back valve 7 and the coating head 8 toward the outlet 8a of the coating head 8 (described later). As a result, the flow rate of the coating material 9 discharged from the outlet 8a increases rapidly. Furthermore, the suck-back valve 7 generates negative pressure in the second flow path 4b between the suck-back valve 7 and the coating head 8 by moving (retracting) its "piston" in a direction away from the coating head 8 or in a direction approaching the outlet 5b of the first intermittent valve 5 (to the left in FIG. 2), and either sucks the coating material 9 present in the second flow path 4b between the suck-back valve 7 and the coating head 8 toward the suck-back valve 7, or suppresses the discharge of the coating material 9 from the outlet 8a of the coating head 8. As a result, the flow rate of the coating material 9 discharged from the outlet 8a drops sharply.

[0018] The above-mentioned flow paths 4 (first flow path 4a, second flow path 4b, and third flow path 4c), first intermittent valve 5, second intermittent valve 6, and suck-back valve 7, etc., constitute the so-called "intermittent coating valve unit" in this coating device 1.

[0019] The coating head 8 is a "nozzle member" also known as a "die head," "die," or "coating die," and discharges the coating material 9 pumped from the pump 3 toward the object to be coated 10. The object to be coated 10 is, for example, a "substrate" in a "battery electrode." In the example shown in FIG. 2, the web-like substrate 10 wound around a backup roll 11 is supplied to the coating position, i.e., the position opposite the outlet 8a at the tip of the coating head 8.

[0020] As described above, the coating device 1 according to an embodiment of the present invention forms an "electrode" material by intermittently coating a web-like substrate 10 with a coating material 9, such as an "electrode material." When performing intermittent coating using the coating device 1, droop inevitably occurs at the end of the portion of the substrate 10 where the coating material 9 has been applied. While droop can be reduced by operating the suck-back valve 7, for example, such droop still occurs. Therefore, the coating device 1 according to an embodiment of the present invention has an improved shape for the valve element 5c of the first intermittent valve 5, allowing the first intermittent valve 5 to be switched between its open and closed states over a narrower operating range and in a shorter operating time (switching time) than conventional valves.

[0021] 3, the valve body 5c of the first intermittent valve 5 has a through hole 5e that allows the coating material 9 to flow between the inlet 5a and the outlet 5b of the first intermittent valve 5 when the first intermittent valve 5 is operated to be in an open state. The through hole 5e is formed in a cross-sectional shape that is flatter than the cross-sectional shapes of the inlet 5a and the outlet 5b of the first intermittent valve 5.

[0022] As shown in Figures 2 and 3, the valve element 5c of the first intermittent valve 5 is configured to rotate around a straight line (rotation axis) AL perpendicular to the flow direction of the coating material 9 at the inlet 5a and outlet 5b of the first intermittent valve 5 (the up-down direction in Figure 2, the left-right direction in Figure 3) within a rotation angle range of less than 90 degrees in the penetration direction of the through hole 5e (i.e., the flow direction of the coating material 9 in the through hole 5e), thereby switching between the open and closed states of the first intermittent valve 5. In the example shown in Figure 3, the valve element 5c is configured to rotate so that the penetration direction of the through hole 5e rotates by 45 degrees in the penetration direction of the through hole 5e, thereby switching between the open and closed states of the first intermittent valve 5. (Note that the position of the rotation axis AL is indicated by a "dot" in Figure 3.)

[0023] As a comparative example, Fig. 4 shows an image of the shape and operation of the valve element 101 in a conventional intermittent valve 100. In the conventional intermittent valve 100, for example, by rotating the valve element 101 by 90 degrees, the intermittent valve 100 can be switched from an open state to a closed state. Similarly, when switching from a closed state to an open state, the valve element 101 is rotated by 90 degrees. In this case, the switching time required for the conventional intermittent valve 100 to switch between the open and closed states is time T.

[0024] In contrast, the first intermittent valve 5 in the embodiment of the present invention can be switched between an open state and a closed state simply by rotating the valve element 5c by 45 degrees, as described above. Therefore, in the first intermittent valve 5 in the embodiment of the present invention, the switching time required to switch the first intermittent valve 5 is reduced to a time T / 2, which is half the conventional switching time T, as shown in Fig. 3 .

[0025] Figure 5 shows the suppression effect of sagging of the coating material 9 when the through-hole 5e of the valve element 5c is formed flat as described above. In Figure 5, "Amm" is the length (measured value) of sagging that occurs when using a conventional intermittent valve 100 that switches between open and closed states by rotating the valve element 101 90 degrees, as shown in Figure 4. "Bms" is the operating time (measured value) required to switch the conventional intermittent valve 100 between open and closed states. "(B+α)ms" is the actual generation time of sagging, which is the operating time (Bms) above, taking into account the liquid properties of the coating material 9 and other factors.

[0026] In contrast, in the first intermittent valve 5 according to the embodiment of the present invention, as described above, the valve element 5c is rotated 45 degrees to switch between the open and closed states of the first intermittent valve 5. Therefore, the operating time of the first intermittent valve 5 is "B / 2 ms," half that of the conventional intermittent valve 100. In this case, the time required for the sagging to occur is "(B / 2 + α) ms," taking into account the liquid characteristics of the coating material 9 and other factors, as described above. If the length of the sagging predicted to occur in the time "α ms" is "β mm," the length of the sagging that occurs when the first intermittent valve 5 according to the embodiment of the present invention is predicted to be "(A / 2 + β) mm." In the example shown in FIG. 5, a 50 to 60% reduction in sagging can be expected compared to the conventional sagging length of "A mm."

[0027] As described above, in the coating device according to the embodiment of the present invention, the first intermittent valve 5 is opened and closed to perform intermittent coating of the coating material 9. The first intermittent valve 5 is opened and closed by rotating the valve element 5c, which has a through hole 5e formed therein. The cross-section of the through hole 5e in the valve element 5c is flattened compared to the cross-sections before and after the through hole 5e, i.e., the cross-sections of the inlet 5a and outlet 5b of the first intermittent valve 5. Therefore, compared to a conventional intermittent valve 100 that opens and closes by rotating the valve element 101 90 degrees, the first intermittent valve 5 can be opened and closed by simply rotating the valve element 5c by a small rotation angle of less than 90 degrees (e.g., half, 45 degrees). When the first intermittent valve 5 is opened and closed by rotating the valve element 101 45 degrees, the time required to open and close the first intermittent valve 5 (operation time) can be reduced by half compared to the conventional case where the valve element is rotated 90 degrees. As a result, it is possible to improve the work efficiency when performing intermittent coating and the productivity of products (e.g., battery electrodes) manufactured using intermittent coating. Furthermore, by shortening the operating time of the first intermittent valve 5 as described above, the time periods during which drooping of the coating material 9 may occur when coating starts and stops during intermittent coating is also shortened. Therefore, it is possible to effectively suppress the occurrence of drooping of the coating material 9 during intermittent coating.

[0028] Therefore, the coating device 1 according to the embodiment of the present invention can suppress the drooping of the coating material 9 that occurs during intermittent coating, and can perform intermittent coating with good productivity. This in turn can improve the performance and quality of batteries manufactured by performing intermittent coating using the coating device 1 according to the embodiment of the present invention. [Explanation of symbols]

[0029] 1 Coating device 2 Tanks 2a (tank) return port 3. Pump 3a (Pump) outlet 4 Flow path 4a (of the flow path) first flow path 4b (of the flow path) second flow path 4c (of the flow channel) third flow channel 5. First intermittent valve (intermittent valve) 5a (First intermittent valve) inlet 5b Outlet (of first intermittent valve) 5c (First intermittent valve) valve body 5d Motor (for first intermittent valve) 5e Through hole (of the valve body of the first intermittent valve) 6. Second intermittent valve 6a (Second intermittent valve) inlet 6b Outlet (of second intermittent valve) 6c (Second intermittent valve) valve body 6d (Second intermittent valve) motor 7 Suck Back Valve 8 Coating head 8a (Coating head) nozzle 9 Coating materials (electrode active materials) 10 Coating object (electrode substrate) 11 Backup Role AL (of the valve disc in the first intermittent valve) rotation axis

Claims

[Claim 1] A coating device comprising: a pump that sucks in and pressure-feeds a liquid coating material; a coating head that discharges the coating material pressure-fed from the pump toward an object to be coated; a flow path that causes the coating material to flow between the pump and the coating head; and an intermittent valve that is provided in the flow path and opens and closes to allow or block the flow of the coating material in the flow path, wherein the coating device intermittently coats the object to be coated with the coating material, The flow path is a first flow path for causing the coating material to flow between the pump and the intermittent valve, and a second flow path for causing the coating material to flow between the intermittent valve and the coating head, The intermittent valve is the coating material supplying device has an inlet connected to the first flow path and through which the coating material flows in, an outlet connected to the second flow path and through which the coating material flows out, and a valve body that opens and closes the inlet and the outlet, The valve body is When the coating material is operated to the open state, the coating material flows between the inlet and the outlet, and the coating material has a through hole formed in a cross-sectional shape that is flatter than the cross-sectional shape of the inlet and the cross-sectional shape of the outlet, The open state and the closed state are switched by rotating the through-hole in a rotation angle range of less than 90 degrees around a straight line perpendicular to the flow direction of the coating material at the inlet and the outlet as a rotation axis. A coating device characterized by:

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