Intermittent valve and intermittent coating device

Abstract

To provide a technique improving coating accuracy of a coating material in intermittent coating.SOLUTION: An intermittent valve comprises: a valve main unit which has an inflow chamber having an upstream end, a first downstream end and a second downstream end and in which a tank is connected to the upstream end; a supply chamber which is connected to the first downstream end and a die and a return chamber which is connected to the second downstream end and the tank; a piston which can be switched between the first position and the second position in the valve main unit; a supply valve allowing a coating material to flow from the inflow chamber to the supply chamber when the piston is in a first position and blocking the flow when the piston is in a second position; and a return valve blocking the coating material from flowing from the inflow chamber to the return chamber when the piston is in the first position and allows the flow when the piston is in the second position. The valve diameter D1 of the supply valve is 1.53 times or more the valve diameter D2 of the return valve.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an intermittent valve and an intermittent coating device. [Background technology]

[0002] In recent years, shipments of secondary batteries have increased with the spread of electric vehicles (EVs), hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), etc. Shipments of lithium-ion secondary batteries have been increasing in particular. A typical secondary battery is mainly composed of a positive electrode plate, a negative electrode plate, a separator, and an electrolyte. Electrode plates such as positive and negative electrodes have a structure in which an electrode active material is layered on the surface of a current collector made of metal foil.

[0003] Conventionally, a known method for manufacturing such an electrode plate involves intermittently applying electrode slurry to the surface of a long metal foil using an intermittent coating device equipped with a die that ejects electrode slurry, which is a mixture of an active material and a solvent, and an intermittent valve that switches between supplying and not supplying the electrode slurry to the die (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-51407 Summary of the Invention

[0005] In order to improve the quality of secondary batteries, it is naturally necessary to improve the application accuracy of electrode slurry in intermittent coating. Meanwhile, with the increase in shipments of secondary batteries, there is a demand to shorten the manufacturing time of electrode plates. However, when electrode slurry is intermittently applied to metal foil at high speed to shorten the manufacturing time of electrode plates, there is a risk that the application accuracy of the electrode slurry will decrease.

[0006] The present invention has been made in view of the above circumstances, and its object is to provide a technique for improving the coating accuracy in intermittent coating.

[0007] One embodiment of the present invention is an intermittent valve that switches between supplying and not supplying paint from a tank that stores paint to a die that applies paint to a workpiece. The intermittent valve includes a valve body having an inlet chamber having an upstream end, a first downstream end, and a second downstream end, the tank being connected to the upstream end, an inlet chamber connected to the first downstream end and the die, and a return chamber connected to the second downstream end and the tank, a piston switchable between a first position and a second position within the valve body, a supply valve fixed to the piston that allows the flow of paint from the inlet chamber to the supply chamber when the piston is in the first position and blocks said flow when the piston is in the second position, and a return valve fixed to the piston that blocks the flow of paint from the inlet chamber to the return chamber when the piston is in the first position and allows said flow when the piston is in the second position, wherein the valve diameter of the supply valve is 1.53 times or more the valve diameter of the return valve.

[0008] Another aspect of the present invention is an intermittent coating device comprising a tank for storing paint, a die for applying paint to an object to be coated, and the intermittent valve of the above aspect for switching between supplying and not supplying paint to the die.

[0009] Any combination of the above components and any transformation of the present invention into a method, device, system, etc. are also valid aspects of the present invention.

[0010] According to the present invention, it is possible to improve the coating accuracy in intermittent coating. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of an intermittent coating device according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically showing an intermittent valve. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. Identical or equivalent components, parts, and processes shown in each drawing are designated by the same reference numerals, and redundant description will be omitted where appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation and should not be interpreted as limiting unless otherwise specified. Furthermore, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are used to distinguish one configuration from another. Furthermore, some components that are not important for explaining the embodiments are omitted from each drawing.

[0013] 1 is a schematic diagram of an intermittent coating device according to an embodiment. The intermittent coating device 1 includes a die 2, an intermittent valve 4, a tank 6, a pump 8, a feed pipe 10, a return pipe 12, and a die supply pipe 14.

[0014] The die 2 is a tool for applying the coating material 18 to the workpiece 16. The intermittent coating apparatus 1 according to this embodiment is used to manufacture electrode plates for secondary batteries. The electrode plate for a secondary battery is a sheet-like electrode material obtained by applying an electrode slurry to a current collector and then drying the applied material. Therefore, in this embodiment, the workpiece 16 is the current collector of the secondary battery, and the coating material 18 is the electrode slurry for the secondary battery. The current collector is, for example, a metal foil. The electrode slurry is, for example, a mixture of a positive electrode active material or a negative electrode active material and a solvent. In a typical lithium-ion secondary battery, the positive electrode plate is prepared by applying a slurry containing a positive electrode active material such as lithium cobalt oxide or lithium iron phosphate to aluminum foil. The negative electrode plate is prepared by applying a slurry containing a negative electrode active material such as graphite to copper foil.

[0015] The die 2 is disposed so that the discharge port 84 faces the peripheral surface of the backup roll 20 at a predetermined distance. As the backup roll 20 rotates, the object 16 to be coated is continuously transported to a position where the backup roll 20 and the discharge port 84 face each other.

[0016] An intermittent valve 4 is connected to the die 2 via a die supply pipe line 14. The intermittent valve 4 is a mechanism that switches between supplying and not supplying paint 18 to the die 2. The intermittent coating device 1 can discharge paint 18 from the die 2 onto a workpiece 16 while paint 18 is being supplied to the die 2. A tank 6 is connected to the intermittent valve 4 via a feed pipe line 10 and a return pipe line 12.

[0017] Tank 6 stores paint 18. Pump 8 is provided in feed pipe 10, and paint 18 is sent from tank 6 to intermittent valve 4 by driving pump 8. Intermittent valve 4 supplies paint 18 supplied from tank 6 to die 2 via die supply pipe 14. Alternatively, intermittent valve 4 returns paint 18 supplied from tank 6 to tank 6 via return pipe 12.

[0018] The intermittent valve 4 supplies the paint 18 to the die 2, which allows the paint 18 to be ejected from the die 2 to form coated areas 18a on the workpiece 16. The intermittent valve 4 also returns the paint 18 to the tank 6, which stops the ejection of the paint 18 from the die 2 and allows the formation of uncoated areas 16a on the workpiece 16 without the paint 18. In other words, the intermittent valve 4 allows the paint 18 to be intermittently applied to the workpiece 16. The uncoated areas 16a are used for attaching the center lead of an electrode, etc.

[0019] 2 is a cross-sectional view schematically illustrating the intermittent valve 4. The intermittent valve 4 includes a valve body 22, a piston 24, a supply valve 26, and a return valve 28. The valve body 22 is a so-called cylinder, and has a first opening 30 on its top surface through which the piston 24 is slidably inserted, and a second opening 32 to which the feed pipe 10 is connected, a third opening 34 to which the return pipe 12 is connected, and a fourth opening 36 to which the die supply pipe 14 is connected on its side surface. Note that, for convenience in describing the present embodiment, the first opening 30 is provided on the top surface and the second opening 32 to fourth openings 36 are provided on the side surfaces, but the orientation of the intermittent valve 4 is not particularly limited.

[0020] The valve body 22 also has an inlet chamber 38, a supply chamber 40, and a return chamber 42 inside. The inlet chamber 38 is a generally T-shaped chamber with one end branching into two, and has an upstream end 38a, a first downstream end 38b, and a second downstream end 38c. The upstream end 38a is connected to the feed pipe 10 via the second opening 32. In other words, the upstream end 38a is connected to the tank 6. The paint 18 flows into the inlet chamber 38 from the upstream end 38a and flows within the inlet chamber 38 toward the first downstream end 38b and the second downstream end 38c.

[0021] The first downstream end 38b is connected to the supply chamber 40. The die supply pipe 14 is connected to the supply chamber 40 via the fourth opening 36. In other words, the supply chamber 40 is connected to the die 2. The paint 18 that flows through the inlet chamber 38 and reaches the first downstream end 38b flows to the die 2 via the supply chamber 40 and the die supply pipe 14. Therefore, the inlet chamber 38 and the supply chamber 40 form part of the flow path for the paint 18 that connects the tank 6 and the die 2.

[0022] The second downstream end 38c is connected to the return chamber 42. The return pipe 12 is connected to the return chamber 42 via the third opening 34. In other words, the return chamber 42 is connected to the tank 6. The paint 18 that flows through the inlet chamber 38 and reaches the second downstream end 38c flows into the tank 6 via the return chamber 42 and the return pipe 12. Therefore, the inlet chamber 38 and the return chamber 42 form part of a flow path through which the paint 18 circulates between the tank 6 and the intermittent valve 4.

[0023] The first opening 30 of the valve body 22, the first connecting portion 44 connecting the first downstream end 38b and the supply chamber 40, and the second connecting portion 46 connecting the second downstream end 38c and the return chamber 42 are arranged in a straight line. The first opening 30, the second connecting portion 46, and the first connecting portion 44 are arranged in this order. The piston 24 is a rod-shaped member, and one end side is inserted through the first opening 30, the second connecting portion 46, and the first connecting portion 44.

[0024] A supply valve 26 is fixed to the piston 24 near the first connecting portion 44. A return valve 28 is fixed to the piston 24 near the second connecting portion 46. The supply valve 26 and the return valve 28 are arranged so that the distance between them in the axial direction X of the piston 24 (the direction in which the axis of the piston 24 extends) is wider than the distance between the first connecting portion 44 and the second connecting portion 46. In this embodiment, the supply valve 26, the return valve 28, the opening of the first connecting portion 44, and the opening of the second connecting portion 46 are each circular when viewed in the axial direction X.

[0025] The piston 24 is displaceable in the axial direction X relative to the valve body 22, thereby being switchable between a first position and a second position within the valve body 22. The piston 24 assumes the first position when it is further into the valve body 22 than when it is in the second position, and assumes the second position when it is further out of the valve body 22 than when it is in the first position. In Figure 2, the piston 24, supply valve 26, and return valve 28 are shown in solid lines when they are in the second position. Furthermore, the supply valve 26 and return valve 28 are shown in dashed lines when the piston 24 is in the first position.

[0026] When the piston 24 is in the first position, a gap is formed between the supply valve 26 and the first connecting portion 44, connecting the inlet chamber 38 and the supply chamber 40. On the other hand, when the piston 24 is in the second position, the supply valve 26 engages with the first connecting portion 44, blocking the connection between the inlet chamber 38 and the supply chamber 40. Therefore, the supply valve 26 allows the flow of paint 18 from the inlet chamber 38 to the supply chamber 40 when the piston 24 is in the first position, and blocks the flow of paint 18 from the inlet chamber 38 to the supply chamber 40 when the piston 24 is in the second position.

[0027] Furthermore, when the piston 24 is in the first position, the return valve 28 engages with the second connecting portion 46, blocking the inlet chamber 38 from the return chamber 42. On the other hand, when the piston 24 is in the second position, a gap is formed between the return valve 28 and the second connecting portion 46, connecting the inlet chamber 38 to the return chamber 42. Therefore, the return valve 28 blocks the flow of paint 18 from the inlet chamber 38 to the return chamber 42 when the piston 24 is in the first position, and allows the flow of paint 18 from the inlet chamber 38 to the return chamber 42 when the piston 24 is in the second position.

[0028] Therefore, when the piston 24 is in the first position, the intermittent valve 4 is in a first state in which the paint 18 is supplied to the die 2, and when the piston 24 is in the second position, the intermittent valve 4 is in a second state in which the supply of the paint 18 to the die 2 is stopped. Specifically, when the intermittent valve 4 is in the first state, the piston 24 is in the first position, so the inlet chamber 38 and the supply chamber 40 are connected to each other, and the inlet chamber 38 and the return chamber 42 are blocked from each other. Therefore, the paint 18 that flows into the inlet chamber 38 from the feed pipe 10 is supplied to the die 2 via the supply chamber 40 and the die supply pipe 14. On the other hand, when the intermittent valve 4 is in the second state, the piston 24 is in the second position, so the inlet chamber 38 and the supply chamber 40 are blocked from each other, and the inlet chamber 38 and the return chamber 42 are connected to each other. Therefore, the paint 18 that flows into the inlet chamber 38 from the feed pipe 10 is returned to the tank 6 via the return chamber 42 and the return pipe 12.

[0029] The piston 24 is switched between a first position and a second position by a drive unit (not shown) connected to the end portion that protrudes outside the valve body 22. The drive unit is composed of a motor such as a servo motor and a crank mechanism or the like that connects the motor and the piston 24. The drive unit may be a known drive source other than a motor, such as an air cylinder.

[0030] When the piston 24 moves from the first position to the second position, it moves in a direction away from the feed chamber 40. Therefore, the volume of the portion of the piston 24 located within the feed chamber 40 decreases. This creates a negative pressure within the feed chamber 40, causing some of the paint 18 to flow back from the die 2. Furthermore, when the supply valve 26 moves toward the first connecting portion 44 in conjunction with the displacement of the piston 24, some of the paint 18 is drawn into the inlet chamber 38 by the supply valve 26. This also causes some of the paint 18 to flow back from the die 2. This backflow of the paint 18 prevents the paint 18 from dripping from the discharge port 84 when the discharge of the paint 18 from the die 2 stops. In other words, a suck-back effect can be achieved.

[0031] In this embodiment, the size of the supply valve 26 is larger than the size of the return valve 28. Specifically, the valve diameter D1 of the supply valve 26 is 1.53 times or more the valve diameter D2 of the return valve 28. In other words, the ratio of the valve diameter D1 of the supply valve 26 to the valve diameter D2 of the return valve 28 (D1 / D2: hereinafter, this ratio will be referred to as the valve diameter ratio as appropriate) is 1.53 or more. Furthermore, the valve diameter ratio is preferably 1.81 or more, and more preferably 2.00 or more. In this embodiment, the valve diameters D1 and D2 of each valve are the sizes of the portions of the valves that are largest in the direction perpendicular to the axial direction X of the piston 24.

[0032] By setting the dimensions of the supply valve 26 and the return valve 28 so that the valve diameter ratio is 1.53 or more, the amount of paint 18 pulled back from the die 2 by the suck-back effect (hereinafter, this amount will be referred to as the suck-back amount as appropriate) can be increased, thereby suppressing the paint 18 from splashing onto the uncoated portion 16a.

[0033] The inventors performed intermittent coating using an intermittent valve of a reference example with a valve diameter ratio of approximately 1.52 and an intermittent valve 4 of an example with a valve diameter ratio of 2.00. The amount (area) of paint 18 scattered onto the uncoated area 16a in the reference example and example was measured using known image analysis and compared. As a result, it was confirmed that, assuming the amount of paint 18 scattered onto the uncoated area 16a in the reference example to be 1, the amount scattered onto the example was reduced to 0.67.

[0034] The inventors also performed intermittent coating using the intermittent valve of the Reference Example, with the flow rate (flow velocity) of the coating material 18 set to 3.2 L / min. They also performed intermittent coating using the intermittent valve 4 of the Example, with the flow rate of the coating material 18 set to 4.0 L / min. As a result, in the intermittent coating using the intermittent valve of the Reference Example, splashing of the coating material 18 onto the uncoated area 16a was observed. On the other hand, in the intermittent coating using the intermittent valve 4 of the Example, it was confirmed that the amount of splashing of the coating material 18 was reduced compared to the Reference Example, despite the increased flow rate. Furthermore, the amount of suck-back in the intermittent valve of the Reference Example was 0.17 mL, while the amount of suck-back in the intermittent valve 4 of the Example was 0.22 mL.

[0035] Generally, as the flow rate of the paint 18 increases, the resistance to the displacement of the piston 24 from the first position to the second position increases. This makes it difficult for the supply valve 26 to close, making it easier for the paint 18 to splash onto the uncoated portion 16a. Despite this tendency, according to this embodiment, the amount of suck-back can be increased, thereby preventing the paint 18 from splashing onto the uncoated portion 16a. The inventors have recognized that if the valve diameter ratio is made larger than at least the reference example, that is, if the valve diameter ratio is set to 1.53 or greater, it is possible to increase the amount of suck-back and prevent the paint 18 from splashing.

[0036] Furthermore, the supply valve 26 of this embodiment has a first flat surface 26a extending in a direction perpendicular to the axial direction X of the piston 24 on a surface facing the first downstream end 38b. The valve body 22 also has a second flat surface 22a that comes into surface contact with the first flat surface 26a when the piston 24 is in the second position. When viewed from the axial direction X, the first flat surface 26a and the second flat surface 22a are located outside the first downstream end 38b. Furthermore, the first flat surface 26a faces upward, and the second flat surface 22a faces downward, facing each other.

[0037] By providing the first flat surface portion 26a, when the piston 24 is displaced from the first position to the second position, a larger amount of paint 18 can be drawn into the inlet chamber 38. This more reliably increases the amount of suck-back. Furthermore, when the piston 24 is in the second position, the first flat surface portion 26a and the second flat surface portion 22a are in surface contact with each other, thereby preventing the paint 18 from leaking from the inlet chamber 38 to the supply chamber 40.

[0038] Furthermore, when the piston 24 is displaced from the second position to the first position, a narrow flow path (hence, high flow path resistance) is formed on the outer periphery of the first downstream end 38b, defined by the first flat portion 26a and the second flat portion 22a. This prevents a large amount of paint 18 from flowing from the inlet chamber 38 into the supply chamber 40 the instant the piston 24 is displaced from the second position to the first position. Furthermore, when the piston 24 is displaced from the second position to the first position, the first flat portion 26a can receive the hydraulic pressure of the paint 18 flowing from the inlet chamber 38 to the supply chamber 40. This allows the supply valve 26 to follow the displacement of the piston 24 with higher accuracy. As a result, the supply and non-supply of paint 18 to the die 2 can be switched with higher accuracy.

[0039] Furthermore, the supply valve 26 has a protrusion 26b that protrudes toward the first downstream end 38b in an area closer to the piston 24 than the first flat portion 26a on the surface facing the first downstream end 38b. When the piston 24 is in the second position, the protrusion 26b fits into the first downstream end 38b. This further prevents the paint 18 from leaking from the inlet chamber 38 to the supply chamber 40.

[0040] Additionally, the supply valve 26 has a tapered portion 26c on the outer edge of the surface facing the first downstream end 38b, which slopes away from the second flat portion 22a in a direction perpendicular to the axial direction X as it moves outward from the supply valve 26. In the intermittent valve 4 of this embodiment, the second opening 32 and the fourth opening 36 are approximately aligned in height. Therefore, the supply chamber 40 extends horizontally from the first connecting portion 44, then extends upward at a position offset from the piston 24 and connects to the fourth opening 36. Therefore, if the valve diameter D1 of the supply valve 26 is large, the outer edge of the supply valve 26 may protrude toward the center of the supply chamber 40 where it bends from the horizontal to the vertical direction, potentially obstructing the flow of paint 18. In response to this, the provision of the tapered portion 26c reduces obstruction of the flow of paint 18 within the supply chamber 40 by the supply valve 26.

[0041] As described above, the intermittent valve 4 according to this embodiment is a mechanism for switching between supplying and not supplying the paint 18 from the tank 6, which stores the paint 18, to the die 2, which applies the paint 18 to the workpiece 16. The intermittent valve 4 includes a valve body 22, a piston 24, a supply valve 26, and a return valve 28. The valve body 22 includes an inlet chamber 38 having an upstream end 38a, a first downstream end 38b, and a second downstream end 38c, and in which the tank 6 is connected to the upstream end 38a; a supply chamber 40 connected to the first downstream end 38b and the die 2; and a return chamber 42 connected to the second downstream end 38c and the tank 6. The piston 24 is switchable between a first position and a second position within the valve body 22. The supply valve 26 is fixed to the piston 24. When the piston 24 is in the first position, the supply valve 26 allows the paint 18 to flow from the inlet chamber 38 to the supply chamber 40, and blocks this flow when the piston 24 is in the second position. The return valve 28 is fixed to the piston 24, and blocks the flow of paint 18 from the inlet chamber 38 to the return chamber 42 when the piston 24 is in the first position, and allows the flow when the piston 24 is in the second position. The valve diameter D1 of the supply valve 26 is set to be 1.53 times or more the valve diameter D2 of the return valve 28.

[0042] By setting the valve diameter D1 of the supply valve 26 to be 1.53 times or more the valve diameter D2 of the return valve 28, the amount of suck-back of the paint 18 when the piston 24 moves from the first position to the second position is increased, thereby suppressing the paint 18 from splashing onto the uncoated portion 16a. This improves the coating accuracy of the paint 18 without complicating the structure of the intermittent valve 4, and therefore the intermittent coating device 1. Furthermore, it is possible to increase the speed of intermittent coating while maintaining the coating accuracy of the paint 18. Therefore, according to this embodiment, it is possible to shorten the manufacturing time of the electrode plates while maintaining quality.

[0043] Furthermore, the supply valve 26 of this embodiment has a first flat surface 26a extending in a direction perpendicular to the axial direction X of the piston 24 on the surface facing the first downstream end 38b. The valve body 22 also has a second flat surface 22a that comes into surface contact with the first flat surface 26a when the piston 24 is in the second position. By providing the first flat surface 26a in the supply valve 26, the amount of suck-back can be more reliably increased. This can further improve the application accuracy of the paint 18. Furthermore, the first flat surface 26a and the second flat surface 22a can prevent the paint 18 from leaking from the inlet chamber 38 to the supply chamber 40. This can further improve the application accuracy of the paint 18.

[0044] Furthermore, the first flat portion 26a and the second flat portion 22a can prevent the flow rate of the coating material 18 from increasing instantaneously when the supply valve 26 is opened. This prevents a sudden increase in the amount of coating material 18 discharged from the die 2 when the intermittent valve 4 switches from the second state to the first state. This prevents the film thickness of the coated portion 18a from increasing in the boundary region with the uncoated portion 16a, making it possible to make the film thickness of the coated portion 18a uniform.

[0045] When the film thickness of the coating portion 18a is made uniform, the entire coating portion 18a can be more reliably pressed during press processing after the coating process of the coating material 18. This increases the density of the entire coating portion 18a and allows the entire coating portion 18a to adhere closely to the workpiece 16. As a result, it is possible to prevent a portion of the coating portion 18a from losing its cell performance or peeling off from the workpiece 16. Furthermore, because the first flat portion 26a receives the hydraulic pressure of the coating material 18 flowing from the inlet chamber 38 to the supply chamber 40, the supply valve 26 can more accurately follow the displacement of the piston 24. This allows the supply and non-supply of the coating material 18 to the die 2 to be switched on and off with greater precision, thereby improving the accuracy of coating the coating material 18.

[0046] The intermittent coating device 1 includes a tank 6 that stores coating material 18, a feed pipeline 10 and a return pipeline 12 that connect the tank 6 and the intermittent valve 4, and a pump 8 that is provided in the feed pipeline 10 and sends the coating material 18 from the tank 6 to the intermittent valve 4. When the intermittent valve 4 is in the second state, the coating material 18 returns to the tank 6 via the return pipeline 12. This allows the coating material 18 to continue to be supplied to the intermittent valve 4 even when the discharge of the coating material 18 from the die 2 has stopped. Therefore, the pump 8 can be kept running at all times, which simplifies the system configuration of the intermittent coating device 1.

[0047] The above describes the embodiments of the present invention in detail. The above-described embodiments merely illustrate specific examples of implementing the present invention. The content of the embodiments does not limit the technical scope of the present invention, and many design modifications, such as changes, additions, and deletions of components, are possible within the scope of the inventive concept defined in the claims. A new embodiment incorporating design modifications will combine the effects of the combined embodiments and modifications. In the above-described embodiments, design modifications that are possible are emphasized by using notations such as "in this embodiment" or "in this embodiment," but design modifications are also permitted even in areas without such notation. Any combination of the above components is also valid as an aspect of the present invention. Hatching in cross sections in the drawings does not limit the materials of the hatched objects.

[0048] In the embodiment, the second opening 32 and the fourth opening 36 are aligned at the same height, and the supply chamber 40 is bent on the way from the first connecting portion 44 to the fourth opening 36, but the fourth opening 36 may be located lower than the second opening 32, and the supply chamber 40 may extend horizontally in a straight line from the first connecting portion 44. [Explanation of symbols]

[0049] 1 Intermittent coating device 2 Die 4 Intermittent Valve 6 Tank 16 Object to be coated 18 Paint 22 Valve body 22a 2nd plane part 24 pistons 26 Supply valve 26a 1st plane part 28 Return valve 38 Inflow chamber 38a Upstream end 38b 1st downstream end 38c 2nd downstream end 40 Supply room 42 Return Room

Claims

1. An intermittent valve that switches between supplying and not supplying the coating material from a tank that stores the coating material to a die that applies the coating material to a workpiece, a valve body having an inlet chamber therein, the inlet chamber having an upstream end and a first downstream end, the tank being connected to the upstream end, and a feed chamber connected to the first downstream end and the die; a piston switchable between a first position and a second position within the valve body; a supply valve fixed to the piston, the supply valve allowing the paint to flow from the inlet chamber to the supply chamber when the piston is in the first position and blocking the flow when the piston is in the second position; the supply valve has a first flat portion on a surface facing the first downstream end, the first flat portion extending in a direction perpendicular to an axial direction of the piston, The valve body has a second flat surface that comes into surface contact with the first flat surface when the piston is in the second position.

2. the inlet chamber further has a second downstream end; The intermittent valve according to claim 1 , wherein the valve body further includes a return chamber therein connected to the second downstream end and the tank.

3. 3. The intermittent valve of claim 2, further comprising a return valve fixed to the piston, the return valve blocking the flow of paint from the inlet chamber to the return chamber when the piston is in the first position and allowing the flow when the piston is in the second position.

4. The intermittent valve according to claim 3 , wherein the supply valve has a larger valve diameter than the return valve.

5. 5. The intermittent valve according to claim 4, wherein the valve diameter of the supply valve is 1.53 times or more the valve diameter of the return valve.

6. the substrate is a current collector of a secondary battery, The intermittent valve according to claim 1 , wherein the paint is an electrode slurry for a secondary battery.

7. A tank for storing paint; a die for applying the coating material to an object to be coated; and an intermittent valve according to any one of claims 1 to 6, which switches between supplying and not supplying the coating material to the die.

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