Battery electrode material coating device

Abstract

This battery electrode material coating device is provided with: a transport unit that transports a conductive substrate; a hopper configured so as to be able to accommodate the powder and provided with a conductive screen; a voltage applying unit capable of applying a voltage between the conveying unit and the hopper; and an ultrasonic vibrator connected to a side wall of the hopper.

Description

Technical Field

[0001] The present invention relates to a battery electrode material coating device. Background Art

[0002] Japanese Patent Laid-Open No. 7-109031 discloses a powder and granular material supply device in which a screen is arranged at the bottom of a hopper. In particular, in the device disclosed in Japanese Patent Laid-Open No. 7-109031, a plurality of vibration plates are provided inside the hopper at a position lower than the screen. By installing an ultrasonic vibrator on a vibration connecting rod connecting these vibration plates, the device has a structure that uniformly applies vibration to the powder and granular material in the hopper. Summary of the invention

[0003] However, in the device described in Japanese Patent Application Laid-Open No. 7-109031, the powder may hit the vibrating connecting rod before being discharged, so that the powder cannot be evenly applied to the coating object.

[0004] An object of the present invention is to provide a battery electrode material coating device capable of uniformly coating a coating object with a powder.

[0005] The battery electrode material coating device according to claim 1 comprises: a conveying portion for conveying a conductive base material; A hopper, which is configured to contain powder and has a conductive screen; a voltage applying unit capable of applying a voltage between the conveying unit and the hopper; and An ultrasonic vibrator is connected to the side wall of the hopper.

[0006] In the battery electrode material coating device involved in Scheme 1, a conductive substrate is transported by a conveying unit. In addition, the hopper is configured to accommodate powder, and a conductive screen is provided on the hopper. In addition, it is configured to be able to apply a voltage between the conveying unit and the hopper through a voltage applying unit. Thus, by supplying a predetermined amount of powder from the hopper to the substrate transported by the conveying unit, the powder is coated on the substrate. Here, since an ultrasonic vibrator is connected to the side wall of the hopper, the powder given ultrasonic vibration can be supplied from the screen to the substrate, and the powder can be evenly coated on the substrate as the coating object.

[0007] According to the battery electrode material coating device involved in scheme 2, In Solution 1, the screen is disposed on the discharge hole of the hopper.

[0008] In the battery electrode material coating apparatus according to the second aspect, since the screen is provided at the discharge hole of the hopper, the powder immediately after passing through the screen can be supplied to the substrate.

[0009] According to the battery electrode material coating device involved in scheme 3, In the first aspect, the ultrasonic vibrator is connected to the hopper at a position lower than the center portion in the vertical direction.

[0010] In the battery electrode material coating device according to claim 3, since the ultrasonic vibrator is connected to the hopper below the center in the vertical direction (downstream), ultrasonic vibration can be efficiently applied to the powder near the discharge hole.

[0011] According to the battery electrode material coating device involved in scheme 4, In any one of schemes 1 to 3, The hopper is arranged with its long side being perpendicular to the direction in which the conveying unit conveys the substrate. The ultrasonic vibrator is connected to a central portion of the hopper in a longitudinal direction.

[0012] In the battery electrode material coating device according to Scheme 4, the hopper is arranged with its long side being perpendicular to the conveying direction of the substrate by the conveying unit. In other words, since the length of the discharge hole of the hopper in the conveying direction is short, the powder can be coated more uniformly in the conveying direction.

[0013] As described above, according to the battery electrode material coating apparatus according to the present invention, powder can be uniformly coated on a coating object. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages and technical and industrial significance of exemplary embodiments of the present invention are described with reference to the accompanying drawings, in which like reference numerals represent like parts, and in which: Figure 1 It is a diagram schematically showing the overall structure of a battery electrode material coating device according to an embodiment. Figure 2 This is a diagram schematically showing the overall structure of a battery electrode material coating device according to a modified example. Figure 3 It is a diagram schematically showing the overall structure of a battery electrode material coating device according to a comparative example. DETAILED DESCRIPTION

[0015] A battery electrode material coating device 10 according to an embodiment will be described with reference to the drawings.

[0016] Figure 1 1 is a diagram schematically showing the overall structure of the battery electrode material coating device 10 according to the present embodiment. Figure 1As shown, the battery electrode material coating device 10 according to the present embodiment is a coating machine for manufacturing a battery electrode plate, and includes a conveying unit 12 , a hopper 18 , a power source 16 as a voltage applying unit, and an ultrasonic vibrator 20 .

[0017] The conveying unit 12 includes a supply-side roller 12A and a recovery-side roller 12B, and the supply-side roller 12A and the recovery-side roller 12B are each configured to rotate by the operation of a motor (not shown).

[0018] A conductive base material 14 is wound between the supply side roller 12A and the collection side roller 12B. As the base material 14, a metal foil or the like is used, for example, a copper foil or an aluminum foil or the like is wound in a roll shape.

[0019] On the supply side roller 12A, the pre-coated substrate 14A before being coated with powder is wound into a roll, and on the recovery side roller 12B, the post-coated substrate 14C after being coated with powder is wound into a roll. By operating a motor (not shown), the supply side roller 12A and the recovery side roller 12B rotate respectively, and the substrate 14 is conveyed from the supply side roller 12A to the recovery side roller 12B. In addition, a hopper 18 is provided above the substrate 14B being conveyed between the supply side roller 12A and the recovery side roller 12B.

[0020] The hopper 18 has openings at upper and lower ends, and is formed in a shape that gradually narrows toward the lower side. The hopper 18 is configured to include a main body 18A and a screen 18B.

[0021] The main body 18A of the hopper 18 is arranged with its longitudinal direction being perpendicular to the conveying direction of the substrate 14 by the conveying unit 12. Figure 1 The main body 18A is arranged in the long side direction with the depth direction of the paper surface in the figure being the long side direction. For example, the length of the long side direction of the main body 18A may be slightly shorter than the width of the transported substrate 14. In addition, the length of the transport direction (short side direction) of the main body 18A is set to be less than 10 mm, for example.

[0022] The powder P is supplied from the supply hole at the upper end of the main body 18A. As the powder P, an active material and a binder constituting an electrode material are used. For example, in the case of a negative electrode material of a lithium ion battery, a composite material of graphite as an active material and a binder is used as the powder P. As the binder, for example, it can be at least one material selected from polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HEP), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyamide-imide (PAI) and polyimide (PI).

[0023] A screen 18B is provided in the discharge hole of the hopper 18. The screen 18B is conductive and has a predetermined pattern. For example, the screen 18B may be a conductive screen whose pattern is partially formed by a mesh material. The powder P is applied to the substrate 14 through the screen 18B, thereby applying the powder P to the substrate 14 in a desired pattern.

[0024] The mesh material of the screen 18B is not particularly limited as long as it is a conductive material. For example, wires such as stainless steel, galvanized iron, brass, and copper with iron as the main component can be used. The size of the mesh is not particularly limited either, and can be appropriately changed according to the pattern.

[0025] Here, the screen 18B and the conveying unit 12 are electrically connected to the power source 16, respectively, and are configured so that a voltage can be applied between the screen 18B and the conveying unit 12 by the power source 16. Furthermore, by passing the powder through the screen 18B with the voltage applied, the mesh and the powder P can be brought into contact with each other, thereby charging the powder P.

[0026] An ultrasonic vibrator 20 is connected to a side wall of the main body 18A in the hopper 18. The ultrasonic vibrator 20 may be any vibrator capable of imparting ultrasonic vibration to the powder in the hopper 18, and the structure and form are not particularly limited.

[0027] In the present embodiment, as an example, the ultrasonic vibrator 20 is connected to the hopper 18 at a position lower than the center portion in the vertical direction. In particular, the ultrasonic vibrator 20 is preferably connected at a position where the amplitude of the vibration imparted to the powder passing through the screen 18B is 50% or more relative to the amplitude of the ultrasonic vibrator 20.

[0028] In addition, from the viewpoint of imparting ultrasonic vibration to the powder P contained in the hopper 18 without bias, the ultrasonic vibrator 20 is preferably connected to the center portion in the longitudinal direction of the hopper 18 . effect

[0029] Next, the operation of the battery electrode material coating device 10 according to this embodiment will be described.

[0030] In the battery electrode material coating device 10 according to the present embodiment, a conductive substrate 14 is conveyed by a conveying unit 12. In addition, a hopper 18 is configured to accommodate a powder P, and a conductive mesh 18B is provided on the hopper 18. In addition, a voltage can be applied between the conveying unit 12 and the hopper 18 by a power supply 16. Thus, a predetermined amount of powder P is supplied from the hopper 18 to the substrate 14 conveyed by the conveying unit 12, and the powder P is coated on the substrate 14.

[0031] Here, an ultrasonic vibrator 20 is connected to the side wall of the hopper 18. Therefore, the powder P to which ultrasonic vibration is applied can be supplied from the mesh 18B to the substrate 14, and the powder can be uniformly applied to the substrate 14 as the coating object.

[0032] In addition, in the present embodiment, since the screen 18B is provided at the discharge hole of the hopper 18 , the powder P immediately after passing through the screen 18B can be supplied to the base material 14 .

[0033] Furthermore, in the present embodiment, since the ultrasonic vibrator 20 is connected to the lower part (downstream side) of the central part of the hopper 18 in the vertical direction, ultrasonic vibration can be efficiently applied to the powder P near the discharge hole of the hopper 18. That is, when the ultrasonic vibrator 20 is connected to the upper part of the hopper 18, the vibration applied to the powder P near the discharge hole becomes smaller due to attenuation, and the effect of ultrasonic vibration may not be fully obtained. In the present embodiment, by connecting the ultrasonic vibrator 20 at a position close to the discharge hole of the hopper 18, ultrasonic vibration before attenuation can be applied to the powder P as described above.

[0034] In this embodiment, the hopper 18 is arranged with its longitudinal direction perpendicular to the conveying direction of the conveyor 12 to the substrate 14. In other words, since the discharge hole of the hopper 18 is short in the conveying direction, the powder can be applied more uniformly with respect to the conveying direction of the substrate 14.

[0035] In addition, in the present embodiment, the length of the main body 18A in the hopper 18 in the conveying direction is set to 10 mm or less, but the present invention is not limited thereto. Figure 2 The structure of the modified example shown. Modifications

[0036] Figure 2 1 is a diagram schematically showing the overall structure of a battery electrode material coating device 30 according to a modified example. Figure 2 As shown, in the battery electrode material coating device 30 according to the present modification, the same configuration as that of the embodiment is adopted except for the hopper 32 .

[0037] The hopper 32 is formed to have a longer length in the conveying direction than the hopper 18 in the embodiment, and is set to, for example, about 30 mm.

[0038] In the battery electrode material coating device 30 according to this modification, similarly to the battery electrode material coating device 10 according to the embodiment, the powder P can be uniformly coated on the substrate 14 by connecting the ultrasonic vibrator 20 to the side wall of the main body 32A in the hopper 32 .

[0039] Hereinafter, the evaluation results of the battery electrode material coating apparatus 10 according to the present invention and the battery electrode material coating apparatus 100 of the comparative example will be described. First, the battery electrode material coating apparatus 100 of the comparative example will be described, and then the evaluation procedure will be described.

[0040] Figure 3 FIG. 1 is a diagram schematically showing the overall structure of a battery electrode material coating device 100 according to a comparative example. Figure 3 As shown, the battery electrode material coating apparatus 100 of the comparative example is configured to include a substrate holder 102 , a hopper 108 , a mesh 112 , a power source 106 , and an ultrasonic vibrator 20 .

[0041] In the structure of the comparative example, the hopper 108 is separated from the screen 112. Specifically, a bottomed cylindrical conductive frame 110 is disposed below the hopper 108, and a conductive screen 112 is disposed at the bottom of the frame 110. In addition, in the structure of the comparative example, a power source 106 is provided so that a voltage can be applied between the frame 110 and the substrate holder 102.

[0042] In addition, in the structure of the comparative example, the ultrasonic vibrator 20 is connected to the side wall of the frame 110, and the ultrasonic vibrator is applied to the frame 110 so that the ultrasonic vibrator is applied to the screen 112 via the frame 110. The powder P supplied from the hopper 108 to the frame 110 is applied with ultrasonic vibration when passing through the screen 112, and is applied to the substrate 104 set on the substrate holder 102. In addition, in the structure of the comparative example, the length of the short side direction (left and right direction of the paper) of the hopper 108 is longer than that of the hopper 18 of the embodiment, and is set to 50 mm.

[0043] The evaluation steps are as follows. (1) Composite negative electrode materials

[0044] As powders used for coating, graphite and PVDF were put into an MP mixer (produced by Nippon Coking Industry Co., Ltd.) and subjected to a composite treatment under the conditions of 10,000 [rpm] and 2 [min]. The average particle size of graphite was 10 to 20 [μm], and the composition ratio of graphite to PVDF was 97.5 / 2.5 [wt %]. (2) Film formation

[0045] exist Figure 1 In the battery electrode material coating apparatus 10 shown, the composited powder P is supplied to the hopper 18, and the powder P is coated on the substrate 14 in an area of ​​100 [mm] x 50 [mm] through the screen 18B set to 300 meshes. On the other hand, Figure 3In the battery electrode material coating apparatus 100 shown, the composited powder P is supplied to the hopper 108 and the powder P is coated on the substrate 104 in an area of ​​100 [mm] x 50 [mm] through the sieve 112 set to 300 meshes. (3) Fixation and densification

[0046] The powder P was fixed to the substrate 14 by applying pressure at 150[°C] and 5[kN] for 1 minute using a flat press, thereby producing an electrode. The powder P was fixed to the substrate 104 by the same procedure, thereby producing an electrode. (4) Determination of electrode weight

[0047] Punch the prepared electrode at 12 locations and measure its weight using an electronic balance. Table 1 below calculates the weight deviations of the 12 locations. Table 1

[0048] As can be seen from the results in Table 1, by coating with the battery electrode material coating device 10 according to the embodiment, the weight variation during electrode production can be reduced compared to the case of using the battery electrode material coating device 100 according to the comparative example. The weight of the electrode depends on the amount per unit area of ​​the powder P to be coated, so it can be seen that in the embodiment, the powder P can be coated more uniformly than in the comparative example.

[0049] In addition, in this embodiment, if Figure 1 As shown, the ultrasonic vibrator 20 is connected to the hopper 18 at a position lower than the vertical center, but the present invention is not limited thereto. For example, the ultrasonic vibrator 20 may be connected to the vertical center of the hopper 18.

[0050] In addition, a structure using a plurality of ultrasonic vibrators 20 may be adopted. For example, two or more ultrasonic vibrators 20 may be connected along the longitudinal direction of the hopper 18.

[0051] In addition, in this embodiment, the conveying unit 12 is configured to include the supply side roller 12A and the recovery side roller 12B, but the present invention is not limited thereto, and other configurations may be used as long as they are capable of conveying the substrate 14. For example, when the substrate is in a sheet form instead of a roll form, a configuration may be used to convey the substrate using a conveyor belt or the like.

[0052] The following supplementary notes are disclosed with respect to the above-mentioned embodiment. Note 1

[0053] A battery electrode material coating device, comprising: a conveying portion for conveying a conductive base material; A hopper, which is configured to contain powder and has a conductive screen; a voltage applying unit capable of applying a voltage between the conveying unit and the hopper; and An ultrasonic vibrator is connected to the side wall of the hopper. Note 2 The battery electrode material coating device according to Supplementary Note 1, wherein the screen is provided on a discharge hole of the hopper. Note 3 The battery electrode material coating device according to Supplementary Note 1 or Supplementary Note 2, wherein the ultrasonic vibrator is connected to the hopper at a position lower than a center portion in a vertical direction. Note 4 The battery electrode material coating device according to any one of Supplementary Notes 1 to 3, wherein the hopper is arranged with a direction perpendicular to a conveying direction of the substrate by the conveying unit as a long side direction, The ultrasonic vibrator is connected to a central portion of the hopper in a longitudinal direction.

Claims

1. A battery electrode material coating device, comprising: a conveying portion for conveying a conductive base material; A hopper, which is configured to contain powder and has a conductive screen; a voltage applying unit capable of applying a voltage between the conveying unit and the hopper; and An ultrasonic vibrator is connected to the side wall of the hopper.

2. The battery electrode material coating device according to claim 1, wherein: The screen is arranged on the discharge hole of the hopper.

3. The battery electrode material coating device according to claim 1, wherein: The ultrasonic vibrator is connected to the hopper at a position lower than the center portion in the vertical direction.

4. The battery electrode material coating device according to any one of claims 1 to 3, wherein: The hopper is arranged with its longitudinal direction being perpendicular to a conveyance direction of the substrate by the conveying unit, and the ultrasonic vibrator is connected to a central portion of the hopper in the longitudinal direction.

Images