Powder discharge device

Abstract

To provide a powder discharge device which can prevent a powder material from clogging a discharge mechanism.SOLUTION: A power discharge device discharges a powder material and includes: a discharge mechanism which is formed elongated in one direction and formed with a discharge port for discharging the powder material, and a discharge passage which is connected to the discharge port to supply the powder material to the discharge port; a gas sending part which sends a gas to the discharge passage; and a hole part which is formed at the discharge mechanism and blows the gas sent from the gas sending part to the discharge passage.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a powder discharge device that discharges powder material. [Background technology]

[0002] In the manufacturing process of electrodes for lithium-ion batteries, a technique is known in which a coating film is formed by applying a slurry, in which an active material, a binder, and the like are mixed in a solvent, to a sheet-like substrate, such as aluminum foil or copper foil, which is transported by a roll-to-roll system. However, this technique requires drying the coating film after formation, and the energy consumed during this drying process accounts for the majority of the energy consumed in the manufacturing process of electrodes for lithium-ion batteries. Therefore, in recent years, there has been a demand for a technique that can form electrodes for lithium-ion batteries without the need for a coating film drying process.

[0003] In response to this, for example, Patent Document 1 below discloses a method for manufacturing electrodes for lithium ion batteries using a powder discharge device that discharges a powder material onto a substrate without mixing an active material (hereinafter, powder material) and a binder with a solvent. The powder discharge device has a discharge mechanism formed with a discharge port for discharging the powder material and a discharge flow path connected to the discharge port and supplying the powder material to the discharge port. The powder material is discharged onto the substrate by this discharge mechanism to form a powder layer. The powder layer formed on the surface of the substrate is then pressed to increase the density of the powder material. This makes it possible to form electrodes for lithium ion batteries without requiring a drying process, thereby reducing the energy consumed in the manufacturing process of electrodes for lithium ion batteries. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-115567 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned powder discharge device sometimes resulted in defects in the formed electrodes for lithium-ion batteries. Specifically, because the above-mentioned powder discharge device discharges powder material without using a solvent, the powder material is prone to agglomeration in the discharge flow path, which can lead to clogging of the discharge mechanism. Furthermore, clogging of the discharge mechanism can lead to unevenness in the amount of powder material discharged from the discharge mechanism, which can result in unevenness in the powder layer formed on the substrate.

[0006] The present invention has been made in consideration of the above problems, and has an object to provide a powder discharge device that can prevent clogging of the discharge mechanism with powder material. [Means for solving the problem]

[0007] In order to solve the above problems, the powder ejection device of the present invention is a powder ejection device that ejects powder material, and is characterized by having an ejection mechanism that is formed long in one direction and has an ejection outlet that ejects the powder material and an ejection flow path that is connected to the ejection outlet and supplies the powder material to the ejection outlet, an air supply unit that supplies gas to the ejection flow path, and a hole unit formed in the ejection mechanism that blows the gas sent from the air supply unit into the ejection flow path.

[0008] According to the powder discharge device, the gas sent by the air supply unit is blown into the discharge flow path through the holes, thereby dispersing the powder material present in the discharge flow path, thereby preventing the powder material from agglomerating in the discharge flow path and allowing the powder material to flow, thereby preventing clogging of the discharge mechanism with the powder material.

[0009] The hole may be formed so that the gas blown into the discharge flow path has an upward velocity component.

[0010] With this configuration, gas can be blown upward into the discharge flow path to blow the powder material from below upward, which reduces the falling speed of the powder material and allows the powder material to be supplied to the discharge port in a dispersed state in the discharge flow path, making it easier to prevent the powder material from clogging the discharge mechanism.

[0011] The hole may be formed in the vicinity of the ejection port.

[0012] This configuration allows gas to be blown upward into the discharge flow path from near the discharge port, dispersing the powder material throughout the discharge flow path, making it easier to prevent clogging of the discharge mechanism with the powder material.

[0013] The hole may be formed in plurality so as to sandwich the discharge port therebetween.

[0014] This configuration allows for a wider area in the discharge flow path into which gas can be injected than when gas is injected into the discharge flow path through a single hole, making it easier to disperse the powder material present in the discharge flow path, thereby more easily preventing clogging of the discharge mechanism with the powder material.

[0015] The discharge mechanism may be configured such that a plurality of holes are formed and arranged along the longitudinal direction of the discharge mechanism.

[0016] This configuration allows the powder material present in the discharge flow path to be dispersed along the longitudinal direction of the discharge mechanism, making it easier to prevent clogging of the discharge mechanism with the powder material. Also, it makes it easier to discharge the amount of powder material from the discharge mechanism uniformly along the longitudinal direction of the discharge mechanism.

[0017] The gas supply unit may be provided with a moisture removal unit that removes moisture contained in the gas supplied to the discharge flow path.

[0018] According to this configuration, the moisture removal unit can remove moisture from the gas sent to the discharge flow path, preventing the powder material from becoming moist and agglomerating, thereby more easily preventing the powder material from clogging the discharge mechanism. [Effects of the Invention]

[0019] According to the powder discharge device of the present invention, clogging of the discharge mechanism with powder material can be prevented. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing a manufacturing facility for electrodes for lithium ion batteries, which is equipped with a powder discharge device according to an embodiment of the present invention. [Figure 2] 1A and 1B are diagrams for explaining a powder discharge device according to an embodiment of the present invention, in which (a) is a side cross-sectional view of a discharge mechanism, and (b) is a view taken along the arrow A in (a). DETAILED DESCRIPTION OF THE INVENTION

[0021] An embodiment of the powder discharge device of the present invention will be described with reference to the drawings. In the following description, the three axes of a Cartesian coordinate system are designated as X, Y, and Z, the horizontal direction is referred to as the X-axis direction and the Y-axis direction, and the direction perpendicular to the XY plane (i.e., the vertical direction) is referred to as the Z-axis direction.

[0022] Fig. 1 is a schematic diagram showing an electrode manufacturing facility 100 equipped with a powder discharge device 2 according to one embodiment of the present invention. Fig. 2 is a diagram for explaining the powder discharge device 2 according to one embodiment of the present invention, in which Fig. 2(a) is a side cross-sectional view of a discharge mechanism 21, and Fig. 2(b) is an enlarged view as viewed from the arrow A in Fig. 2(a).

[0023] The electrode manufacturing equipment 100 is for forming electrodes for lithium-ion batteries. As shown in Fig. 1, the electrode manufacturing equipment 100 includes a conveying device (not shown) that conveys a substrate 1, a powder discharging device 2 that discharges a powder material 11 (see Fig. 1) that is an electrode material onto the substrate 1 to form a powder layer 12 (see Fig. 1), and a pressing mechanism 3 that presses and consolidates the powder layer 12.

[0024] The substrate 1 is a metal foil that will become an electrode plate for a lithium-ion battery; for example, aluminum foil is used to form a positive electrode, and copper foil is used to form a negative electrode. The substrate 1 is a strip-shaped sheet that is long in one direction, and is transported by a transport device through each component of the electrode manufacturing equipment 100. The powder material 11 is a powdered active material. The powder material 11 is discharged onto the substrate 1 by the powder discharge device 2, whereby the powder material 11 is layered on the substrate 1 to form a powder layer 12.

[0025] The conveying device is for conveying the substrate 1 by a roll-to-roll method. This conveying device includes an unwinding roll that unwinds the substrate 1, a take-up roll that winds up the substrate 1, and a plurality of conveying rolls through which the substrate 1 unwound by the unwinding roll passes before being wound up by the take-up roll. By rotating these rolls, the substrate 1 is conveyed so as to pass through each part constituting the electrode manufacturing equipment 100.

[0026] The powder discharge device 2 is for discharging powder material 11 onto the substrate 1 conveyed by the conveying device to form a powder layer 12. As shown in Figures 1 and 2(a), the powder discharge device 2 includes a discharge mechanism 21 that discharges the powder material 11, a supply mechanism 4 that supplies the powder material 11 to the discharge mechanism 21, and a spraying unit 51 that sprays a binder onto the powder material 11 discharged by the discharge mechanism 21.

[0027] The discharge mechanism 21 is for discharging the powder material 11 onto the substrate 1, and is disposed so as to be located directly above the substrate 1 being transported. That is, the discharge mechanism 21 is configured to discharge the powder material 11 vertically downward. The discharge mechanism 21 is formed long in one direction, and in this embodiment, is formed long along the width direction (the Y-axis direction in FIG. 1 ) in the in-plane direction of the substrate 1, which is perpendicular to the transport direction of the substrate 1. That is, in this embodiment, the longitudinal direction of the discharge mechanism 21 and the width direction of the substrate 1 are the same direction.

[0028] 2(a), the discharge mechanism 21 is formed with a discharge port 22 for discharging the powder material 11, a discharge flow path 23 connected to the discharge port 22 for supplying the powder material 11 to the discharge port 22, and a supply port 24 through which the powder material 11 is supplied. The discharge flow path 23 is a flow path for the powder material 11 and is formed long in the width direction. The discharge flow path 23 is formed in the discharge mechanism 21 so as to be open in the direction of gravity, and in this embodiment, the lower open end is the discharge port 22 and the upper open end is the supply port 24. That is, the powder material 11 supplied from the supply port 24 to the discharge flow path 23 is discharged from the discharge port 22 by gravity. 2(a) of the discharge port 22, the discharge flow path 23, and the supply port 24 are equal in size in the X-axis direction and the Y-axis direction, which reduces the pressure of the powder material 11 and the friction of the inner wall of the discharge mechanism 21 more than when, for example, the discharge flow path 23 is tapered so that the dimensions in the X-axis direction and the Y-axis direction decrease toward the discharge port 22. This makes it less likely for the powder material 11 to clog the discharge mechanism 21.

[0029] The supply mechanism 4 is for supplying the powder material 11 to the discharge mechanism 21, and includes a tank (not shown) that stores the powder material 11, and a tray unit 41 for supplying the powder material 11 from the tank to the discharge mechanism 21. The tank is provided above the discharge mechanism 21. The tray unit 41 is formed in a flat plate shape and is disposed so as to incline from the tank toward the supply port 24 so as to guide the powder material 11 to the supply port 24. As a result, the powder material 11 guided from the tank to the supply port 24 by the tray unit 41 is supplied from the supply port 24 to the discharge flow path 23.

[0030] Furthermore, the dimension of the tray portion 41 in the longitudinal direction of the discharge mechanism 21 is formed to be equivalent to the dimension of the supply port 24 in the longitudinal direction of the discharge mechanism 21. This allows the powder material 11 to be supplied to the discharge flow path 23 so that the amount of powder material 11 is uniform in the longitudinal direction of the discharge mechanism 21. Furthermore, the tray portion 41 may be formed in a substantially U-shape or a substantially V-shape. In this case, it is possible to prevent the powder material 11 from scattering from the tray portion 41.

[0031] The spraying unit 51 is a spray for spraying a binder onto the powder material 11 discharged by the discharge mechanism 21 to bond the powder material 11 together to be stacked on the substrate 1, and in this embodiment, as shown in Fig. 1, is arranged so as to spray the binder onto the powder material 11 from the upstream side of the discharge mechanism 21 in the conveyance direction of the substrate 1. By using this spraying unit 51 to spray the binder onto the powder material 11 discharged from the discharge mechanism 21, the powder material 11 to be stacked on the substrate 1 are bonded together to form a powder layer 12.

[0032] The press mechanism 3 is configured to press the powder layer 12 formed on the substrate 1 to increase the density of the powder material 11. As shown in FIG. 1 , the press mechanism 3 is located downstream of the discharge mechanism 21 in the conveyance direction of the substrate 1. The press mechanism 3 has two sets of press rolls 31 and 32 that sandwich the substrate 1 from above and below to press the powder layer 12 formed on the substrate 1. These two sets of press rolls 31 and 32 are aligned along the conveyance direction of the substrate 1. That is, the conveyed substrate 1 passes through the two sets of press rolls 31 and 32 to press the powder layer 12. The press rolls 31 and 32 are also positioned such that the distance between the press rolls 32a and 32b of one set of press rolls 31 located downstream of the other set of press rolls 31 is narrower than the distance between the press rolls 31a and 31b of the other set of press rolls 31. That is, the powder layer 12 pressed by one set of press rolls 31 is further pressed by the other set of press rolls 32. This increases the density of the powder material 11 to form an electrode for a lithium ion battery.

[0033] The powder discharge device 2 further includes a dispersion mechanism that disperses the powder material 11 in the discharge flow path 23. The dispersion mechanism in this embodiment uses a gas such as air to disperse the powder material 11 present in the discharge flow path 23, and as shown in FIG. 2(a), includes an air supply unit 61 that supplies gas to the discharge flow path 23, and a hole 62 that blows the gas supplied from the air supply unit 61 into the discharge flow path 23.

[0034] The gas sending unit 61 is for sending gas toward the discharge flow path 23. The gas sending unit 61 in this embodiment has a pipe 63 through which the gas flows and a fan (not shown) for sending the gas. The hole 62 is an opening for blowing the gas sent by the gas sending unit 61 into the discharge flow path 23, and is formed in the discharge mechanism 21 so as to communicate with the discharge flow path 23. The pipe 63 is connected to this hole 62, and as shown by the two-dot chain line B in FIG. 2(a), the fan sends gas to the hole 62 through the pipe 63, and the gas is blown into the discharge flow path 23 through the hole 62.

[0035] In this way, the dispersion mechanism can disperse the powder material 11 present in the discharge flow path 23 by sending gas using the gas sending unit 61 and blowing the gas into the discharge flow path 23 through the hole 62. This can prevent the powder material 11 from agglomerating in the discharge flow path 23 and allow the powder material 11 to flow. This can prevent the powder material 11 from clogging the discharge mechanism 21.

[0036] Furthermore, while the discharge mechanism 21 is discharging the powder material 11, the gas supply unit 61 continues to supply gas to the discharge flow path 23. Therefore, while the powder material 11 is present in the discharge flow path 23, the powder material 11 can continue to be dispersed in the discharge flow path 23. This allows the powder material 11 to continue to flow in the discharge flow path 23 while it is being discharged, preventing clogging of the discharge mechanism 21 with the powder material 11. Furthermore, the powder material 11 present in the discharge flow path 23 can be prevented from leaking out of the hole 62.

[0037] 2(a), the holes 62 are formed so as to slope upward from the outer wall of the discharge mechanism 21 toward the discharge flow path 23. That is, the holes 62 are formed so that the gas blown into the discharge flow path 23 has an upward velocity component. Therefore, by blowing the gas upward into the discharge flow path 23, the powder material 11 can be blown up from below, which reduces the falling speed of the powder material 11 and allows the powder material 11 to be supplied to the discharge port 22 in a dispersed state in the discharge flow path 23. This makes it easier to prevent clogging of the powder material 11 within the discharge mechanism 21. The gas blown into the discharge flow path 23 is exhausted from the supply port 24.

[0038] 2(a), a plurality of holes 62 are formed on the upstream and downstream sides of the conveyance direction of the substrate 1, sandwiching the discharge port 22 therebetween. Pipes 63 are connected to each hole 62, and gas is supplied by a fan or pump. That is, the dispersion mechanism blows gas into the discharge flow path 23 from the upstream and downstream sides of the conveyance direction of the substrate 1. Therefore, when blowing gas into the discharge flow path 23 from either the upstream or downstream side of the conveyance direction of the substrate 1, the gas can be blown into areas of the discharge flow path 23 where gas could not be supplied and the powder material 11 could not be dispersed, thereby dispersing the powder material 11. This makes it easier to prevent clogging of the powder material 11 within the discharge mechanism 21.

[0039] 2(a), the hole 62 is formed near the discharge port 22. Preferably, the hole 62 is formed in the discharge mechanism 21 so as to communicate with the discharge flow path 23 as far downward as possible in the vertical direction. This allows gas to be blown upward from the vicinity of the discharge port 62 into the discharge flow path 23, thereby dispersing the powder material 11 throughout almost the entire discharge flow path 23 in the vertical direction. This makes it easier to prevent the powder material 11 from clogging the discharge mechanism 21.

[0040] 2(b), a plurality of holes 62 are formed and arranged along the longitudinal direction of the discharge mechanism 21. Pipes 63 are connected to each of the holes 62, and gas is supplied by a fan. That is, the agitation mechanism 6 blows gas into the discharge flow path 23 along the longitudinal direction of the discharge mechanism 21. This makes it possible to disperse the powder material 11 throughout the entire discharge flow path 23 in the longitudinal direction of the discharge mechanism 21, which makes it easier to prevent the powder material 11 from clogging inside the discharge mechanism 21 and makes it easier to uniformize the amount of powder material 11 discharged from the discharge mechanism 21 along the longitudinal direction of the discharge mechanism 21.

[0041] The gas supply unit 61 is also provided with a moisture removal unit (not shown) that removes moisture contained in the gas supplied to the discharge flow path 23. The moisture removal unit is a membrane that collects moisture in the gas, and is provided midway along the piping 63. That is, the moisture removal unit removes moisture from the gas before the gas is blown into the discharge flow path 23 through the piping 63 and the hole 62. This makes it possible to remove moisture from the gas supplied to the discharge flow path 23, thereby preventing the powder material 11 from becoming moist and agglomerating. This makes it easier to prevent the powder material 11 from clogging the discharge mechanism 21.

[0042] As described above, according to the powder discharge device 2 of the above embodiment, the dispersion mechanism can disperse the powder material 11 present in the discharge flow path 23, thereby suppressing aggregation of the powder material 11 in the discharge flow path 23 and allowing the powder material 11 to flow. This prevents clogging of the discharge mechanism 21 with the powder material 11.

[0043] Furthermore, the dispersion mechanism disperses the powder material 11 present in the discharge flow path 23 by blowing the gas sent by the gas sending unit 61 into the discharge flow path 23 through the holes 62, which makes it easier to make the amount of powder material 11 discharged from the discharge port 23 uniform compared to when a stirrer is provided in the discharge flow path 23 and rotated to stir and disperse the powder material 11. That is, the dispersion mechanism in the above embodiment disperses the powder material 11 by gas without providing a stirrer in the discharge flow path 23, which could hinder the discharge of the powder material 11, making it easier to make the amount of powder material 11 discharged from the discharge port 22 uniform.

[0044] Furthermore, since the dispersion mechanism blows gas upward into the discharge flow path 23, it is less likely that the powder material 11 will fall toward the discharge outlet 22 than when gas is blown downward into the discharge flow path 23 or when the discharge mechanism 21 is vibrated up and down, and this makes it possible to prevent an excessive amount of powder material 11 from being discharged from the discharge outlet 23.

[0045] Although the embodiments of the present invention have been described above in detail with reference to the drawings, the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible without departing from the spirit of the present invention. For example, in the above embodiment, the holes 62 are formed so that the gas blown into the discharge flow path 23 has an upward velocity component, but this is not limited to this. For example, the holes 62 may be formed so that the gas blown into the discharge flow path 23 has a velocity component in a direction opposite to the discharge direction of the powder material 11.

[0046] In addition, in the above embodiment, an example was described in which multiple hole portions 62 are formed on the upstream and downstream sides of the conveying direction of the substrate 1 so as to sandwich the discharge port 22 therebetween, but multiple hole portions 62 may also be formed on at least one in-plane direction of the substrate 1 so as to sandwich the discharge port 32 therebetween.

[0047] Furthermore, in the above embodiment, the example in which the discharge mechanism 21 is formed long along the width direction of the substrate 1 has been described, but the present invention is not limited to this.

[0048] Furthermore, in the above embodiment, an example was described in which multiple hole portions 62 were formed along the width direction, but instead of providing multiple hole portions 62, the hole portions 62 may be formed in the shape of a slit that is long in the width direction.

[0049] In addition, in the above embodiment, an example was described in which a binder is sprayed onto the powder material 11 discharged from the discharge mechanism 21 by the spraying section 51, but it is also possible to disperse the powder binder in advance into the powder material 11 without providing the spraying section 51.

[0050] In addition, in the above embodiment, an example was described in which the moisture removal unit is a membrane that collects moisture in the gas, but it may also be a condenser that liquefies and recovers the moisture in the gas by cooling the gas.

[0051] In the above embodiment, an example has been described in which the powder discharge device 2 discharges the powder material 11 onto the substrate 1 being transported by the transport device, but this is not limiting. For example, the powder material 11 may be discharged onto a fixed substrate 1. Alternatively, a roll (not shown) may be provided in contact with the substrate 1, and the powder material 11 may be discharged onto the roll and transferred from the roll onto the substrate 1, thereby forming a powder layer 12 on the substrate 1. [Explanation of symbols]

[0052] 100 Electrode manufacturing equipment 1 Base material 11 Powder materials 12 Powder layer 2 Powder discharge device 21 Discharge mechanism 22 Discharge port 23 Discharge flow path 24 Supply port 3 Press mechanism 31 Press Roll 32 Press Roll 4 Supply mechanism 41 Tray section 51 Spraying section 61 Air supply unit 62 Hole 63 Piping

Claims

1. A powder discharge device that discharges a powder material, a discharge mechanism including a discharge port formed long in one direction and for discharging the powder material, and a discharge flow path connected to the discharge port and for supplying the powder material to the discharge port; a gas supply unit that supplies gas to the discharge flow path; a hole formed in the discharge mechanism for blowing gas sent from the gas sending section into the discharge flow path.

2. 2. The powder discharge device according to claim 1, wherein the holes are formed so that the gas blown into the discharge flow path has an upward velocity component.

3. 3. The powder ejection device according to claim 2, wherein the hole is formed in the vicinity of the ejection port.

4. The powder ejection device according to claim 3 , wherein a plurality of the holes are formed so as to sandwich the ejection port.

5. 5. The powder discharge device according to claim 1, wherein the hole is formed in a plurality of holes and arranged along the longitudinal direction of the discharge mechanism.

6. 5. The powder discharge device according to claim 1, wherein the gas supply unit is provided with a moisture removal unit that removes moisture contained in the gas supplied to the discharge flow path.

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