Battery electrode material application device

Abstract

To obtain a battery electrode material application device which can apply a powder to an application object uniformly.SOLUTION: A battery electrode material application device 10 includes: a transport part 12 which transports a conductive base material 14; a hopper 18 which is configured to house a powder P and includes a conductive screen 18B; a voltage application part 16 which may apply a voltage to an area between the transport part 12 and the hopper 18; and an ultrasonic vibrator 20 connected to a side wall of the hopper 18.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electrode material application device for a battery. [Background technology]

[0002] Patent Document 1 discloses a powder / granular material supplying device in which a screen is disposed under a hopper. In particular, the device disclosed in Patent Document 1 has a structure in which a plurality of vibration plates are provided inside the hopper below the screen, and an ultrasonic vibrator is attached to a vibration connecting rod that connects these vibration plates, thereby applying vibrations uniformly to the powder / granular material in the hopper. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-109031 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the device described in Patent Document 1, the powder may hit the vibrating connecting rod before being discharged, which may result in the powder not being applied uniformly to the object to be coated.

[0005] An object of the present invention is to provide a battery electrode material application device capable of uniformly applying powder to an object to be applied. [Means for solving the problem]

[0006] The battery electrode material application device according to claim 1 includes a conveying unit that conveys a conductive base material, a hopper configured to accommodate powder and equipped with a conductive screen, a voltage application unit that can apply a voltage between the conveying unit and the hopper, and an ultrasonic vibrator connected to a side wall of the hopper.

[0007] In the battery electrode material application device according to claim 1, a conductive base material is conveyed by a conveying unit. The hopper is configured to be able to contain powder, and a conductive screen is provided in the hopper. A voltage application unit is configured to be able to apply a voltage between the conveying unit and the hopper. As a result, a predetermined amount of powder is supplied from the hopper to the base material conveyed by the conveying unit, and the powder is applied to the base material. Here, an ultrasonic vibrator is connected to the side wall of the hopper, so that the powder to which ultrasonic vibration has been applied can be supplied from the screen to the base material, and the powder can be uniformly applied to the base material, which is the object to be coated.

[0008] The battery electrode material applying device according to claim 2 is the same as claim 1, wherein the screen is provided at a discharge hole of the hopper.

[0009] In the battery electrode material application device according to claim 2, since a screen is provided at the discharge hole of the hopper, the powder can be supplied to the substrate immediately after passing through the screen.

[0010] The battery electrode material applying device according to claim 3 is in accordance with claim 1, wherein the ultrasonic vibrator is connected to a portion of the hopper lower than a central portion in a vertical direction.

[0011] In the battery electrode material application device of claim 3, the ultrasonic vibrator is connected lower (downstream) than the vertical center of the hopper, so that ultrasonic vibration can be effectively applied to the powder close to the discharge hole.

[0012] The battery electrode material application device according to claim 4 is a battery electrode material application device according to any one of claims 1 to 3, wherein the hopper is arranged with its longitudinal direction perpendicular to the direction in which the base material is transported by the transport section, and the ultrasonic transducer is connected to a central portion of the hopper in the longitudinal direction.

[0013] In the battery electrode material application device according to claim 4, the hopper is disposed with its longitudinal direction perpendicular to the direction in which the substrate is conveyed by the conveying unit. In other words, the length of the discharge hole of the hopper in the conveying direction is shortened, so that the powder can be applied more uniformly in the conveying direction. Effect of the Invention

[0014] As described above, the battery electrode material application device according to the present invention can apply powder uniformly to an object to be applied. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram showing an overall configuration of a battery electrode material application device according to an embodiment of the present invention; [Diagram 2] FIG. 13 is a diagram illustrating an overall configuration of a battery electrode material application device according to a modified example. [Diagram 3] FIG. 2 is a diagram illustrating an overall configuration of a battery electrode material application device according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] A battery electrode material application apparatus 10 according to an embodiment will be described with reference to the drawings.

[0017] Fig. 1 is a diagram showing a schematic overall configuration of a battery electrode material application apparatus 10 according to the present embodiment. As shown in Fig. 1, the battery electrode material application apparatus 10 according to the present embodiment is a coater for manufacturing an electrode plate for a battery, and includes a conveying section 12, a hopper 18, a power source 16 as a voltage application section, and an ultrasonic vibrator 20.

[0018] The conveying section 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 configured to rotate by the operation of a motor (not shown).

[0019] A conductive base material 14 is wound between the supply side roller 12A and the recovery side roller 12B. A metal foil or the like is used as the base material 14, and for example, a copper foil or an aluminum foil is used in a rolled state.

[0020] A pre-coated substrate 14A before being coated with powder is wound in a roll around the supply roller 12A, and a post-coated substrate 14C after being coated with powder is wound in a roll around the recovery roller 12B. By operating a motor (not shown), the supply roller 12A and the recovery roller 12B rotate, and the substrate 14 is transported from the supply roller 12A to the recovery roller 12B. A hopper 18 is provided above the substrate 14B being transported between the supply roller 12A and the recovery roller 12B.

[0021] The hopper 18 is formed in a shape that is open at both the top and bottom ends and gradually narrows toward the bottom, and is configured to include a main body 18A and a screen 18B.

[0022] The main body 18A of the hopper 18 is disposed with its longitudinal direction perpendicular to the direction in which the substrate 14 is conveyed by the conveying section 12. That is, the main body 18A is disposed with its longitudinal direction extending in the depth direction of the paper in Fig. 1. For example, the longitudinal length of the main body 18A may be slightly shorter than the width of the substrate 14 to be conveyed. Moreover, the length of the main body 18A in the conveying direction (short side direction) is set to, for example, 10 mm or less.

[0023] Powder P is supplied from a supply hole at the upper end of the main body 18A. As the powder P, an active material constituting an electrode material and a binder are used. For example, in the case of a negative electrode material of a lithium ion battery, a composite material of graphite, which is 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), polyamideimide (PAI), and polyimide (PI) may be used.

[0024] A screen 18B is provided at the discharge hole of the hopper 18. The screen 18B is conductive and has a predetermined pattern formed thereon. For example, the screen 18B may be a conductive screen in which the pattern portion is formed of a mesh material. The powder P passes through the screen 18B and is applied onto the substrate 14, whereby the powder P is applied onto the substrate 14 in a desired pattern.

[0025] The mesh material of the screen 18B is not particularly limited as long as it is conductive. For example, wire materials such as stainless steel containing iron as the main component, zinc-plated iron, brass, and copper may be used. The size of the mesh is not particularly limited, and may be changed appropriately depending on the pattern.

[0026] Here, the screen 18B and the transport section 12 are each electrically connected to a power source 16, and a voltage can be applied between the screen 18B and the transport section 12 by the power source 16. When powder passes through the screen 18B with a voltage applied, the mesh comes into contact with the powder P and charges the powder P.

[0027] An ultrasonic vibrator 20 is connected to a side wall of the main body 18A of the hopper 18. The structure and type of the ultrasonic vibrator 20 are not particularly limited as long as the ultrasonic vibrator 20 is a vibrator capable of applying ultrasonic vibrations to the powder in the hopper 18.

[0028] In this embodiment, as an example, the ultrasonic vibrator 20 is connected to a lower part of the hopper 18 relative to the vertical center. In particular, the ultrasonic vibrator 20 is preferably connected to a position where the amplitude of the vibration applied to the powder passing through the screen 18B is 50% or more of the amplitude of the ultrasonic vibrator 20.

[0029] In order to apply ultrasonic vibrations evenly to the powder P contained in the hopper , it is preferable that the ultrasonic vibrator 20 is connected to the center of the hopper in the longitudinal direction.

[0030] (action) Next, the operation of the battery electrode material application device 10 according to this embodiment will be described.

[0031] In the battery electrode material application device 10 according to this embodiment, a conductive base material 14 is conveyed by a conveying unit 12. A hopper 18 is configured to be able to contain powder P, and a conductive screen 18B is provided in the hopper 18. A voltage can be applied between the conveying unit 12 and the hopper 18 by a power source 16. As a result, a predetermined amount of powder P is supplied from the hopper 18 to the base material 14 conveyed by the conveying unit 12, so that the powder P is applied to the base material 14.

[0032] Here, an ultrasonic vibrator 20 is connected to the side wall of the hopper 18. Therefore, the powder P to which ultrasonic vibration has been applied can be supplied from the screen 18B to the substrate 14, and the powder can be uniformly applied to the substrate 14, which is the coating target.

[0033] In addition, in this embodiment, since the screen 18B is provided at the discharge hole of the hopper 18, the powder P can be supplied to the substrate 14 immediately after passing through the screen 18B.

[0034] Furthermore, in this embodiment, since the ultrasonic vibrator 20 is connected lower (downstream) than the central portion in the vertical direction of the hopper 18, ultrasonic vibration can be effectively applied to the powder P close to the discharge hole of the hopper 18. In other words, if 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 may become small due to attenuation, and the effect of the ultrasonic vibration may not be fully obtained. In this embodiment, since the ultrasonic vibrator 20 is connected to 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.

[0035] Furthermore, in this embodiment, the hopper 18 is disposed so that its longitudinal direction is perpendicular to the conveying direction of the substrate 14 by the conveying section 12. In other words, since the length of the discharge hole of the hopper 18 in the conveying direction is shortened, the powder can be applied more uniformly in the conveying direction of the substrate 14.

[0036] In this embodiment, the length of the main body 18A of the hopper 18 in the conveying direction is set to 10 mm or less, but is not limited to this. For example, a modified structure shown in FIG. 2 may be adopted.

[0037] (Modification) 2 is a diagram showing a schematic overall configuration of a modified battery electrode material application apparatus 30. As shown in FIG. 2, the modified battery electrode material application apparatus 30 has the same configuration as the embodiment except for the hopper 32.

[0038] The hopper 32 is formed so that its length in the conveying direction is longer than that of the hopper 18 in the embodiment, and is set to, for example, about 30 mm.

[0039] In the battery electrode material application apparatus 30 of this modified example, as in the battery electrode material application apparatus 10 of the embodiment, an ultrasonic vibrator 20 is connected to the side wall of the main body 32A of the hopper 32, so that the powder P can be uniformly applied to the substrate 14.

[0040] (Example) Hereinafter, a description will be given of the evaluation results of the battery electrode material application apparatus 10 according to the present invention and the comparative battery electrode material application apparatus 100. First, the comparative battery electrode material application apparatus 100 will be described, and then the evaluation procedure will be described.

[0041] 3 is a diagram showing a schematic overall configuration of a battery electrode material application apparatus 100 according to a comparative example. As shown in FIG. 3, the battery electrode material application apparatus 100 according to the comparative example includes a substrate holder 102, a hopper 108, a screen 112, a power source 106, and an ultrasonic transducer 20.

[0042] In the structure of the comparative example, the hopper 108 and the screen 112 are separated. Specifically, a bottomed, cylindrical, conductive frame 110 is disposed below the hopper 108, and a conductive screen 112 is disposed on 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.

[0043] Furthermore, in the structure of the comparative example, ultrasonic vibrator 20 is connected to the side wall of frame body 110, and by attaching the ultrasonic vibrator to frame body 110, the ultrasonic vibrator is attached to screen 112 via frame body 110. Powder P supplied from hopper 108 to frame body 110 is subjected to ultrasonic vibration when passing through screen 112, and is applied to substrate 104 placed on substrate holder 102. In the structure of the comparative example, the length of hopper 108 in the short side direction (left-right direction on the paper) is set to 50 mm, which is longer than hopper 18 of the embodiment.

[0044] The evaluation procedure is as follows.

[0045] (1) Composite negative electrode materials Graphite and PVDF were added to an MP mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) as the powders to be applied, and the composite process was carried out at 10,000 rpm for 2 min. The average particle size of the graphite was 10 to 20 μm, and the composition ratio of graphite to PVDF was 97.5 / 2.5 wt%.

[0046] (2) Film formation In the battery electrode material application device 10 shown in FIG. 1, the composite-treated powder P was supplied to a hopper 18, and the powder P was applied to the substrate 14 in an area of ​​100 mm × 50 mm from a screen 18B set to 300 mesh. On the other hand, in the battery electrode material application apparatus 100 shown in FIG. 3, the composite-treated powder P was supplied to a hopper 108, and the powder P was applied to the substrate 104 in an area of ​​100 mm x 50 mm from a screen 112 set to 300 mesh.

[0047] (3) Fixation and densification Using a flat press, pressure is applied at 150[℃] and 5[kN] for 1 minute to fix the powder P to the substrate 14, thereby producing an electrode. Using the same procedure, the powder P is fixed to the substrate 104, thereby producing an electrode.

[0048] (4) Measurement of electrode weight The produced electrode was punched out at 12 locations, and the weight was measured using an electronic balance. Table 1 below shows the calculated weight variation at 12 locations.

[0049] [Table 1]

[0050] The results in Table 1 show that coating with the battery electrode material coating apparatus 10 according to the embodiment can reduce the variation in weight during electrode fabrication, compared to the case where the battery electrode material coating apparatus 100 of the comparative example is used. Since the weight of the electrode depends on the amount of powder P to be coated per unit area, it can be seen that the embodiment can coat the powder P more uniformly than the comparative example.

[0051] In this embodiment, as shown in Fig. 1, the ultrasonic transducer 20 is connected to a portion lower than the central portion of the hopper 18 in the vertical direction, but the present invention is not limited to this. For example, the ultrasonic transducer 20 may be connected to the central portion of the hopper 18 in the vertical direction.

[0052] Also, it may have a structure using a plurality of ultrasonic transducers 20. For example, two or more ultrasonic transducers 20 may be connected along the longitudinal direction of the hopper 18.

[0053] Furthermore, in this embodiment, the conveying unit 12 is configured to include the supply-side roller 12A and the recovery-side roller 12B, but is not limited thereto, and other structures may be adopted as long as they are capable of conveying the substrate 14. For example, if the substrate is in a sheet shape rather than a roll shape, the substrate may be conveyed by a belt or the like.

[0054] Regarding the above embodiment, the following notes are disclosed.

[0055] (Appendix 1) A conveying unit that conveys a conductive base material; a hopper configured to receive powder and having a conductive screen; a voltage application unit capable of applying a voltage between the transport unit and the hopper; an ultrasonic transducer connected to a side wall of the hopper; The battery electrode material coating device has (Appendix 2) 2. The battery electrode material application device according to claim 1, wherein the screen is provided at a discharge hole of the hopper. (Appendix 3) The battery electrode material application device according to claim 1 or 2, wherein the ultrasonic vibrator is connected to a portion of the hopper lower than a central portion in a vertical direction. (Appendix 4) The hopper is disposed such that a direction perpendicular to a direction in which the base material is conveyed by the conveying unit is a longitudinal direction, 4. The battery electrode material application device according to any one of claims 1 to 3, wherein the ultrasonic vibrator is connected to a central portion in a longitudinal direction of the hopper. [Explanation of symbols]

[0056] 10,30 Battery electrode material coating device 12 Conveyor section 14 Base material 16 Power supply (voltage application part) 18,32 Hopper 18B,32B screen 20 Ultrasonic transducer P powder

Claims

1. A conveying unit that conveys a conductive base material; a hopper configured to receive powder and having a conductive screen; a voltage application unit capable of applying a voltage between the transport unit and the hopper; an ultrasonic transducer connected to a side wall of the hopper; The battery electrode material coating device has

2. The battery electrode material applying device according to claim 1 , wherein the screen is provided at a discharge hole of the hopper.

3. The battery electrode material application device according to claim 1 , wherein the ultrasonic vibrator is connected to a portion of the hopper lower than a central portion in a vertical direction.

4. The hopper is disposed such that a direction perpendicular to a direction in which the base material is conveyed by the conveying unit is a longitudinal direction, 4. The battery electrode material application device according to claim 1, wherein the ultrasonic vibrator is connected to a central portion in a longitudinal direction of the hopper.

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