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; a conductive wire mesh disposed between the base material conveyed by the conveyance unit and the hopper; a voltage applying unit capable of applying a voltage between the conveying unit and the wire mesh; and an inclined plate extending obliquely downward from the wire mesh.

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 wire mesh 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 below the wire mesh. By installing an ultrasonic vibrator on a vibration connecting rod connecting these vibration plates, the device has a structure for uniformly applying 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, since the powder collides with the vibrating connecting rod before being discharged, there is a possibility 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 Embodiment 1 comprises: a conveying portion for conveying a conductive base material; a hopper configured to receive powder; a conductive wire mesh disposed between the substrate conveyed by the conveying unit and the hopper; a voltage applying unit capable of applying a voltage between the conveying unit and the screen; and The inclined plate extends obliquely downward from the wire mesh.

[0006] In the battery electrode material coating device involved in method 1, a conductive substrate is transported by a conveying unit. In addition, the hopper is configured to accommodate powder. Furthermore, a conductive screen is arranged between the substrate transported by the conveying unit and the hopper. And, it is configured to be able to apply a voltage between the conveying unit and the screen by a voltage applying unit. Thus, a predetermined amount of powder is supplied from the hopper to the substrate transported by the conveying unit via the screen, and the powder is coated on the substrate. Here, an inclined plate extends obliquely downward from the screen. Thus, the powder that has passed through the screen is dispersed in the process of sliding over the inclined plate, and the powder can be evenly coated on the substrate.

[0007] Regarding the battery electrode material coating device according to Embodiment 2, In aspect 1, the inclined plate extends to a vicinity of the substrate transported by the transport unit.

[0008] In the battery electrode material coating apparatus according to the second aspect, the inclined plate extends to the vicinity of the substrate, so that the powder falling from the inclined plate can be suppressed from being uneven.

[0009] Regarding the battery electrode material coating device according to Embodiment 3, In the embodiment 1, a plurality of inclined plates are provided along the conveying direction of the substrate.

[0010] In the battery electrode material coating apparatus according to the third aspect, a plurality of inclined plates are provided, so that even if the screen length is long, the powder can be uniformly coated on the substrate.

[0011] Regarding the battery electrode material coating device according to Embodiment 4, In Embodiment 1, the inclined plate is set at an angle of not less than 45 degrees and not more than 80 degrees with respect to the screen.

[0012] In the battery electrode material coating device according to Embodiment 4, by setting the angle of the inclined plate to 45 degrees or more relative to the screen, the powder can be prevented from being retained on the inclined plate compared to the case where the angle is less than 45 degrees. In addition, by setting the angle of the inclined plate to 80 degrees or less relative to the screen, the powder can be prevented from falling without contacting the inclined plate compared to the case where the angle is greater than 80 degrees.

[0013] Regarding the battery electrode material coating device according to Embodiment 5, In any one of aspects 1 to 4, a frame holding the screen is provided below the hopper, and an ultrasonic vibrator is connected to a side wall of the frame.

[0014] In the battery electrode material coating device according to aspect 5, a frame holding the screen is provided below the hopper, and an ultrasonic vibrator is connected to a side wall of the frame, so that ultrasonic vibration can be applied to the powder passing through the screen.

[0015] 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

[0016] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements. Figure 1 1 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 3It is a diagram schematically showing the overall structure of a battery electrode material coating device according to a comparative example. DETAILED DESCRIPTION

[0017] A battery electrode material coating device 10 according to an embodiment will be described with reference to the drawings.

[0018] 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 1 As shown, the battery electrode material coating device 10 involved in this embodiment is a coating machine for manufacturing an electrode plate of a battery. The battery electrode material coating device 10 is composed of a conveying unit 12, a frame 15, a screen 17, a hopper 18, a power supply 16 as a voltage applying unit, an ultrasonic vibrator 20 and an inclined plate 22.

[0019] The conveying unit 12 includes a supply-side roller 12A and a collection-side roller 12B. The supply-side roller 12A and the collection-side roller 12B are each configured to rotate by the operation of a motor (not shown).

[0020] 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, and for example, a copper foil, an aluminum foil or the like is used in a state of being wound in a roll shape.

[0021] A pre-coated substrate 14A before being coated with powder is wound in a roll shape on the supply side roller 12A, and a post-coated substrate 14C after being coated with powder is wound in a roll shape on the recovery side roller 12B. By operating a motor (not shown), the supply side roller 12A and the recovery side roller 12B rotate respectively, and the substrate 14 is transported from the supply side roller 12A to the recovery side roller 12B. Then, the powder P is coated on the transported substrate 14B between the supply side roller 12A and the recovery side roller 12B.

[0022] A frame 15 is provided above the substrate 14B being transported. The frame 15 includes a bottom wall 15A and a side wall 15B and is formed in a substantially box shape, with an open top. In addition, a screen 17 is held on the bottom wall 15A of the frame 15, and the screen 17 is located below a hopper 18 described later. In other words, the screen 17 is arranged between the substrate 14 transported by the transport unit 12 and the hopper 18.

[0023] The screen 17 is conductive and has a predetermined pattern. For example, the screen 17 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 17, so that the powder P is applied to the substrate 14 in a desired pattern.

[0024] The mesh material of the screen 17 is not particularly limited as long as it is conductive. For example, stainless steel with iron as the main component, galvanized iron, brass, copper, etc. can be used. The size of the mesh is not particularly limited and can be appropriately changed according to the pattern.

[0025] A hopper 18 is disposed above the screen 17. The upper and lower ends of the hopper 18 are open, and the width gradually narrows as it goes downward. In addition, the hopper 18 of this embodiment is disposed with the direction perpendicular to the conveying direction of the conveying unit 12 to the substrate 14 as the long side direction. Figure 1 The hopper 18 is arranged with the depth direction of the paper surface in FIG. 1 as the longitudinal direction. For example, the length of the longitudinal direction of the hopper 18 may be slightly shorter than the width of the substrate 14 to be transported.

[0026] The powder P is supplied from the supply hole at the upper end of the hopper 18. 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, 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) can be used.

[0027] Here, the side wall 15B of the frame 15 and the conveying unit 12 are electrically connected to the power source 16, respectively, so that the power source 16 can apply a voltage between the screen 17 and the conveying unit 12. Furthermore, the powder passes through the screen 17 in a state where a voltage is applied, so that the mesh contacts the powder P and the powder P can be charged.

[0028] The ultrasonic vibrator 20 is connected to the side wall 15B of the frame 15. The ultrasonic vibrator 20 may be any vibrator capable of applying ultrasonic vibration to the powder in the hopper 18, and the structure and form are not particularly limited.

[0029] In the present embodiment, as an example, the ultrasonic vibrator 20 is connected to the lower end of the side wall 15B in the frame 15, and is configured to be able to directly apply ultrasonic vibration to the bottom wall 15A. In addition, the ultrasonic vibrator 20 is preferably connected to the central part of the hopper 18 in the long side direction at an angle that applies ultrasonic vibration to the powder P contained in the hopper 18 without bias.

[0030] The inclined plate 22 is attached to the screen 17. The inclined plate 22 extends obliquely downward from the lower surface of the screen 17, and in the present embodiment, as an example, is inclined in the conveyance direction as it goes from the screen 17 to the substrate 14 (below).

[0031] In the present embodiment, as an example, three inclined plates 22 are attached to the screen 17 . The three inclined plates 22 are attached at equal intervals along the conveyance direction of the substrate 14 , and extend to the vicinity of the substrate 14 .

[0032] Furthermore, the three inclined plates 22 are respectively set at an angle of 45 degrees or more and 80 degrees or less with respect to the screen 17. In the present embodiment, as an example, the three inclined plates 22 are set at an angle of 70 degrees with respect to the screen 17. In addition, the angle of the inclined plates 22 can be changed according to the material of the supplied powder. effect

[0033] Next, the operation of the battery electrode material coating device 10 according to this embodiment will be described.

[0034] 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. Furthermore, a conductive screen 17 is arranged between the substrate 14 conveyed by the conveying unit 12 and the hopper 18. In addition, a voltage is applied between the conveying unit 12 and the screen 17. Thus, a predetermined amount of powder P is supplied from the hopper 18 to the substrate 14 conveyed by the conveying unit 12 via the screen 17, and the powder P is applied to the substrate 14.

[0035] Furthermore, the screen 17 is provided with an inclined plate 22 extending obliquely downward from the screen 17 . Thus, the powder P passing through the screen 17 is dispersed while sliding on the inclined plate 22 , and the powder P can be uniformly applied to the substrate 14 .

[0036] In particular, in the present embodiment, the inclined plate 22 extends to the vicinity of the substrate 14B being conveyed, so that it is possible to suppress the powder P from falling from the inclined plate 22 from being unevenly applied. That is, it is possible to suppress the powder P from being unevenly applied.

[0037] In addition, in the present embodiment, a plurality of inclined plates 22 are provided along the conveying direction. Therefore, even if the length of the screen 17 is long in the conveying direction, the powder P can be uniformly applied to the base material 14.

[0038] Furthermore, in the present embodiment, the angle of the inclined plate 22 is set to an angle of 45 degrees or more and 80 degrees or less relative to the screen. Thus, compared with the case where the inclined angle of the inclined plate 22 is less than 45 degrees, the powder P can be suppressed from being retained on the inclined plate 22. That is, the smaller the angle of the inclined plate 22, the harder it is for the powder P to slide, and there is a possibility that the powder P will be retained on the inclined plate 22. In the present embodiment, by setting the inclined angle of the inclined plate 22 to be 45 degrees or more, the powder can be made to slide well on the inclined plate 22 regardless of the type of powder to be applied.

[0039] On the other hand, if the angle of the inclined plate 22 relative to the screen 17 is too large, the powder P may not contact the inclined plate and fall from the screen 17 to the substrate 14. In addition, in order to make the powder P contact the inclined plate 22 reliably, the interval between adjacent inclined plates 22 needs to be narrowed, so the number of inclined plates 22 increases. In this embodiment, by setting the inclination angle of the inclined plate 22 to 80 degrees or less, it is possible to prevent the powder P from falling without contacting the inclined plate 22.

[0040] Furthermore, in this embodiment, an ultrasonic vibrator 20 is connected to the side wall 15B of the frame 15, so as to apply ultrasonic vibration to the screen 17. Thus, the powder P can be made to slide on the inclined plate 22 through the screen 17 in a dispersed state without brushing the powder P with a dedicated roller or scraper.

[0041] In particular, in the present embodiment, since the ultrasonic vibrator 20 is connected to the lower portion of the side wall 15B of the frame 15 , ultrasonic vibration can be applied to the screen 17 in an adjustable manner.

[0042] In addition, in this embodiment, the structure in which the screen 17 is held in the frame 15 is adopted, but it is not limited to this. Figure 2 The structure of the modified example shown. Modifications

[0043] 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, the battery electrode material coating device 30 according to this modification is different from the embodiment in that it does not have a frame 15 .

[0044] In this modification, a hopper 32 is disposed above the substrate 14B being conveyed. The hopper 32 has openings at upper and lower ends, and is formed to be narrower in width as it goes downward, and is shorter in length along the conveying direction than the hopper 18 of the embodiment.

[0045] A screen 34 is provided at the lower end of the hopper 32. The screen 34 is installed in the discharge hole of the hopper 32 and is arranged between the substrate 14B being conveyed and the hopper 32. In addition, an inclined plate 22 is installed on the screen 34, and the inclined plate 22 extends obliquely downward from the lower surface of the screen 34. In addition, in the present embodiment, as an example, an inclined plate 22 is installed so as to be inclined in the conveying direction as it goes from the screen 34 to the substrate 14 (below).

[0046] The ultrasonic vibrator 20 is connected to the side wall of the hopper 32. The ultrasonic vibrator 20 is connected to the side wall of the hopper 32 at a lower side than the center portion in the vertical direction.

[0047] In this modification, similarly to the embodiment, the inclined plate 22 extends downward from the screen 34 , so the powder P passing through the screen 34 is dispersed while sliding over the inclined plate 22 , and the powder P can be evenly applied to the substrate 14 .

[0048] 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.

[0049] 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 screen 112 , a power source 106 , and an ultrasonic vibrator 20 .

[0050] In the comparative example structure, a frame 110 is disposed below the hopper 108, and a conductive mesh 112 is disposed on a bottom wall 110A of the frame 110. In addition, in the comparative example structure, a power source 106 is provided so that a voltage can be applied between the frame 110 and the substrate holder 102.

[0051] Furthermore, in the structure of the comparative example, the ultrasonic vibrator 20 is connected to the side wall 110B of the frame 110, and ultrasonic vibration is applied to the frame 110, thereby applying ultrasonic vibration to the screen 112 through the frame 110. Here, in the structure of the comparative example, the inclined plate 22 is not provided. Therefore, the powder P supplied from the hopper 108 to the frame 110 is applied with ultrasonic vibration when passing through the screen 112, and directly falls and is coated on the substrate 104 set on the substrate holder 102.

[0052] The evaluation steps are as follows. (1) Composite negative electrode materials

[0053] As powders used for coating, graphite and PVDF were put into an MP mixer (manufactured by COKE & ENGINEERING, Japan), and compounding treatment was performed under the conditions of 10000 [rpm] and 2 [min]. The average particle size of graphite was set to 10-20 [μm], and the composition ratio of graphite to PVDF was set to 97.5 / 2.5 [wt %]. (2) Film formation

[0054] exist Figure 1In 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×50 mm through the screen 17 set to 300 meshes. On the other hand, Figure 3 In 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 a screen 112 set to 300 meshes. (3) Fixation and densification

[0055] 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 to produce an electrode. The powder P was fixed to the substrate 104 by the same procedure to produce an electrode. (4) Determination of electrode weight

[0056] The produced electrode was punched out at 12 locations, and the weight was measured using an electronic scale. Table 1 below calculates the weight fluctuations at 12 locations. Table 1 Example Comparative Example Weight fluctuation [%] ±5 ±59

[0057] As can be seen from the results in Table 1, the weight fluctuation during electrode preparation can be reduced by coating using the battery electrode material coating device 10 according to the embodiment, compared with 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 in the embodiment, the powder P can be coated more uniformly than in the comparative example.

[0058] In addition, in this embodiment, if Figure 1 As shown in the figure, the ultrasonic vibrator 20 is connected to the side wall 15B of the frame body 15, but the present invention is not limited to this, and the ultrasonic vibrator 20 may be not provided.

[0059] In this embodiment, the ultrasonic vibrator 20 is connected to the lower portion of the side wall 15B of the frame 15, but the present invention is not limited thereto. For example, the ultrasonic vibrator 20 may be connected to the middle portion of the side wall 15B in the vertical direction.

[0060] Furthermore, in this embodiment, three inclined plates 22 are provided, but the present invention is not limited thereto, and the number and angle of the inclined plates 22 may be changed. For example, the number of inclined plates 22 may be increased so that adjacent inclined plates 22 overlap when the screen 17 is viewed from the top and bottom.

[0061] Furthermore, in the present embodiment, the angles of the three inclined plates 22 are set to the same angle, but the present invention is not limited thereto, and the inclination angle of each inclined plate 22 may be changed. For example, the angle of the inclined plate 22 farther from the side wall 15B to which the ultrasonic vibrator 20 is connected may be increased, and the angle of the inclined plate 22 closer to the side wall 15B to which the ultrasonic vibrator 20 is connected may be decreased. Thus, by adjusting the angle of the inclined plate 22 according to the attenuation of the ultrasonic vibration, the same amount of powder P can be dropped from all the inclined plates 22 per unit time.

[0062] In addition, in the present embodiment, the conveying unit 12 is configured to include a supply side roller 12A and a recovery side roller 12B, but the present invention is not limited thereto, and other structures may be used as long as the structure can convey the substrate 14. For example, when the substrate is in a sheet shape rather than a roll shape, a structure may be used to convey the substrate using a belt or the like.

[0063] The following supplementary notes are disclosed with respect to the above-mentioned embodiment.

[0064] Note 1 A battery electrode material coating device, comprising: a conveying portion for conveying a conductive base material; a hopper configured to receive powder; a conductive wire mesh disposed between the substrate conveyed by the conveying unit and the hopper; a voltage applying unit capable of applying a voltage between the conveying unit and the screen; and The inclined plate extends obliquely downward from the wire mesh. Note 2 The battery electrode material coating device according to Note 1, wherein: The inclined plate extends to a vicinity of the substrate conveyed by the conveying unit. Note 3 The battery electrode material coating device according to Note 1 or Note 2, wherein: A plurality of the inclined plates are provided along the conveying direction of the substrate. Note 4 The battery electrode material coating device according to any one of Notes 1 to 3, wherein the inclined plate is set at an angle of 45 degrees or more and 80 degrees or less with respect to the screen. Note 5 The battery electrode material coating device according to any one of Notes 1 to 4, wherein a frame holding the wire mesh is provided below the hopper, An ultrasonic vibrator is connected to the side wall of the frame.

Claims

1. A battery electrode material coating device, comprising: a conveying portion for conveying a conductive base material; a hopper configured to receive powder; a conductive wire mesh disposed between the substrate conveyed by the conveying unit and the hopper; a voltage applying unit capable of applying a voltage between the conveying unit and the screen; and The inclined plate extends obliquely downward from the wire mesh.

2. The battery electrode material coating device according to claim 1, wherein: The inclined plate extends to a vicinity of the substrate conveyed by the conveying unit.

3. The battery electrode material coating device according to claim 1, wherein: A plurality of the inclined plates are provided along the conveying direction of the substrate.

4. The battery electrode material coating device according to claim 1, wherein: The inclined plate is set at an angle of not less than 45 degrees and not more than 80 degrees with respect to the screen.

5. The battery electrode material coating device according to any one of claims 1 to 4, wherein: A frame holding the wire mesh is provided below the hopper. An ultrasonic vibrator is connected to the side wall of the frame.

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