Battery electrode material coating 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 apparatus for coating an electrode material for a battery.

Background Art

[0002] Patent Document 1 discloses a powder supply apparatus in which a screen is disposed at the lower part of a hopper. In particular, in the apparatus disclosed in Patent Document 1, a plurality of vibration plates are provided inside the hopper below the screen, and an ultrasonic vibrator is attached to a vibration connecting rod connecting these vibration plates, so that a structure is provided that uniformly applies vibration to the powder in the hopper.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the apparatus described in Patent Document 1 above, there is a possibility that the powder cannot be uniformly applied to the object to be coated because the powder hits the vibration connecting rod before being discharged.

[0005] An object of the present invention is to obtain an apparatus for coating an electrode material for a battery that can uniformly apply powder to an object to be coated.

Means for Solving the Problems

[0006] The apparatus for coating an electrode material for a battery according to claim 1 includes a conveying unit that conveys a conductive base material, The device is configured to contain powder, with openings at both the upper and lower ends, and includes a main body that gradually narrows towards the bottom, and a conductive screen provided in the lower discharge hole of the main body. a hopper, 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 Main body and has The conveying unit is configured to include a supply-side roller and a recovery-side roller, with the substrate wrapped around the supply-side roller and the recovery-side roller, and the voltage application unit is configured to apply a voltage between the screen and the recovery-side roller.

[0007] In the battery electrode material coating apparatus according to claim 1, a conductive substrate is conveyed by a conveying unit. A hopper is configured to contain powder, and a conductive screen is provided in the hopper. Furthermore, a voltage application unit is configured to apply voltage between the conveying unit and the hopper. As a result, a predetermined amount of powder is supplied from the hopper to the substrate conveyed by the conveying unit, thereby coating the substrate with powder. Here, since an ultrasonic transducer is connected to the side wall of the hopper, ultrasonically vibrated powder can be supplied from the screen to the substrate, allowing for uniform application of powder to the substrate, which is the object to be coated.

[0009] Also, the main body Since a screen is provided at the discharge hole, the powder can be supplied to the substrate immediately after passing through the screen. The battery electrode material coating apparatus according to claim 2, in claim 1, wherein the main body is arranged with its longitudinal direction perpendicular to the direction in which the substrate is transported by the transport unit, and its length along the transport direction is set to 10 mm or less.

[0010] The electrode material coating apparatus for a battery according to claim 3, wherein, in claim 1, the ultrasonic transducer is the Main body In this configuration, it is connected to the lower part of the central section in the vertical direction.

[0011] In the battery electrode material coating apparatus according to claim 3, since the ultrasonic transducer is connected to the lower (downstream) part of the hopper below the central part in the vertical direction, ultrasonic vibrations can be effectively applied to the powder near the discharge hole. [Effects of the Invention]

[0014] As described above, the battery electrode material coating apparatus according to the present invention can uniformly coat the object to be coated with powder. [Brief explanation of the drawing]

[0015] [Figure 1] This diagram schematically shows the overall configuration of a battery electrode material coating apparatus according to an embodiment. [Figure 2] This diagram schematically shows the overall configuration of a battery electrode material coating apparatus according to a modified example. [Figure 3]This diagram schematically shows the overall configuration of a battery electrode material coating apparatus according to a comparative example. [Modes for carrying out the invention]

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

[0017] Figure 1 is a schematic diagram showing the overall configuration of the battery electrode material coating apparatus 10 according to this embodiment. As shown in Figure 1, the battery electrode material coating apparatus 10 according to this embodiment is a coater for manufacturing battery electrode plates and is composed of a transport unit 12, a hopper 18, a power supply 16 as a voltage application unit, and an ultrasonic transducer 20.

[0018] The conveying unit 12 is composed of a supply-side roller 12A and a recovery-side roller 12B, and the supply-side roller 12A and the recovery-side roller 12B are configured to rotate when a motor (not shown) is operated.

[0019] A conductive substrate 14 is wound between the supply-side roller 12A and the recovery-side roller 12B. The substrate 14 can be made of metal foil or the like, for example, copper foil or aluminum foil, wound into a roll.

[0020] The supply roller 12A has the uncoated substrate 14A wound in a roll shape before the powder is applied, and the recovery roller 12B has the coated substrate 14C wound in a roll shape after the powder has been applied. By operating a motor (not shown), the supply roller 12A and the recovery roller 12B rotate, and the substrate 14 is conveyed from the supply roller 12A to the recovery roller 12B. A hopper 18 is provided above the conveyed substrate 14B that is being conveyed between the supply roller 12A and the recovery roller 12B.

[0021] The hopper 18 is formed in a shape where the upper and lower ends are each open and gradually narrows downward, and is configured to include a main body portion 18A and a screen 18B.

[0022] The main body portion 18A of the hopper 18 is arranged with the longitudinal direction being perpendicular to the conveyance direction of the base material 14 by the conveyance portion 12. That is, the main body portion 18A is arranged with the depth direction of the paper surface in FIG. 1 as the longitudinal direction. For example, the length in the longitudinal direction of the main body portion 18A may be slightly shorter than the width of the conveyed base material 14. Also, the length in the conveyance direction (short side direction) of the main body portion 18A is set to, for example, 10 mm or less.

[0023] The powder P is supplied from the supply hole at the upper end of the main body portion 18A of the hopper 18. As the powder P, an active material and a binder that constitute an electrode material are used. For example, in the case of the negative electrode material of a lithium-ion battery, a composite material of graphite as the 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 has conductivity and a predetermined pattern is formed. For example, the screen 18B may be a conductive screen in which the pattern portion is formed of a mesh material. By applying the powder P onto the base material 14 through the screen 18B, the powder P is applied onto the base material 14 in a desired pattern.

[0025] The mesh material of the screen 18B is not particularly limited as long as it has conductivity. For example, wire materials such as stainless steel mainly composed of iron, zinc-plated iron, brass, and copper may be used. The size of the mesh is also not particularly limited and may be appropriately changed according to the pattern.

[0026] Here, the screen 18B and the conveying unit 12 are electrically connected to the power supply 16, and the power supply 16 is configured to apply a voltage between the screen 18B and the conveying unit 12. When the powder passes through the screen 18B with the voltage applied, the mesh comes into contact with the powder P, and the powder P is charged.

[0027] An ultrasonic transducer 20 is connected to the side wall of the main body 18A of the hopper 18. The ultrasonic transducer 20 is not particularly limited in structure or method, as long as it is a transducer capable of applying ultrasonic vibrations to the powder inside the hopper 18.

[0028] In this embodiment, as an example, the ultrasonic transducer 20 is connected to the hopper 18 below the central part in the vertical direction. In particular, the connection position of the ultrasonic transducer 20 is preferably such that the amplitude of the vibration applied to the powder passing through the screen 18B is 50% or more of the amplitude of the ultrasonic transducer 20.

[0029] Furthermore, in order to apply ultrasonic vibrations evenly to the powder P contained in the hopper 18, it is preferable that the ultrasonic transducer 20 be connected to the central portion in the longitudinal direction of the hopper 18.

[0030] (action) Next, the operation of the battery electrode material coating apparatus 10 according to this embodiment will be explained.

[0031] In the battery electrode material coating apparatus 10 according to this embodiment, a conductive substrate 14 is conveyed by a conveying unit 12. A hopper 18 is configured to contain powder P, and a conductive screen 18B is provided in the hopper 18. Furthermore, a voltage can be applied between the conveying unit 12 and the hopper 18 by a power supply 16. As a result, a predetermined amount of powder P is supplied from the hopper 18 to the substrate 14 conveyed by the conveying unit 12, thereby coating the substrate 14 with powder P.

[0032] Here, an ultrasonic transducer 20 is connected to the side wall of the hopper 18. As a result, the powder P, which has been subjected to ultrasonic vibration, 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 object to be coated.

[0033] Furthermore, in this embodiment, since a 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 substrate 14.

[0034] Furthermore, in this embodiment, since the ultrasonic transducer 20 is connected to the lower (downstream) part of the hopper 18 below the central part in the vertical direction, ultrasonic vibrations can be effectively applied to the powder P near the discharge hole of the hopper 18. In other words, if the ultrasonic transducer 20 is connected to the upper part of the hopper 18, the vibrations applied to the powder P near the discharge hole will be reduced due to attenuation, and the effect of ultrasonic vibrations may not be fully obtained. In this embodiment, by connecting the ultrasonic transducer 20 to a position close to the discharge hole of the hopper 18, as described above, ultrasonic vibrations before attenuation can be applied to the powder P.

[0035] Furthermore, in this embodiment, the hopper 18 is positioned with its longitudinal direction perpendicular to the direction in which the substrate 14 is conveyed by the conveying unit 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 with respect to the conveying direction of the substrate 14.

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

[0037] (modified version) Figure 2 is a schematic diagram showing the overall configuration of a modified battery electrode material coating apparatus 30. As shown in Figure 2, the battery electrode material coating apparatus 30 according to this modified example has the same configuration as the embodiment, except for the hopper 32.

[0038] The hopper 32 is formed to have a longer length in the conveying direction compared to the hopper 18 in the embodiment, and is set to, for example, about 30 mm.

[0039] In the battery electrode material coating apparatus 30 according to this modified example, similar to the battery electrode material coating apparatus 10 according to the embodiment, the ultrasonic transducer 20 is connected to the side wall of the main body 32A of the hopper 32, thereby enabling uniform application of the powder P to the substrate 14.

[0040] (Examples) The following describes the evaluation results of the battery electrode material coating apparatus 10 according to the present invention and the comparative example battery electrode material coating apparatus 100. First, the comparative example battery electrode material coating apparatus 100 will be described, and then the evaluation procedure will be explained.

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

[0042] In the comparative example, the hopper 108 and the screen 112 are separated. Specifically, a bottomed cylindrical conductive frame 110 is placed below the hopper 108, and the conductive screen 112 is placed at the bottom of this frame 110. In addition, in the comparative example, a power supply 106 is installed so that a voltage can be applied between the frame 110 and the substrate holder 102.

[0043] Furthermore, in the comparative example structure, the ultrasonic transducer 20 is connected to the side wall of the frame 110, and by attaching the ultrasonic transducer to the frame 110, the ultrasonic transducer is attached to the screen 112 via the frame 110. The powder P supplied from the hopper 108 to the frame 110 is subjected to ultrasonic vibration as it passes through the screen 112 and is applied to the substrate 104 installed in the substrate holder 102. In the comparative example structure, the length of the hopper 108 in the shorter direction (left-right direction on the paper) is longer than that of the hopper 18 in the embodiment, and is set to 50 mm.

[0044] The evaluation procedure is as follows:

[0045] (1) Composite formation of negative electrode materials For the powder used in coating, graphite and PVDF were placed in an MP mixer (manufactured by Nippon Coke Industries Co., Ltd.) and compounded under the conditions of 10,000 rpm and 2 min. The average particle size of the graphite was set to 10-20 [μm]. The composition ratio of graphite to PVDF was set to 97.5 / 2.5 [wt%].

[0046] (2) Film formation In the battery electrode material coating apparatus 10 shown in Figure 1, compounded powder P is supplied to the hopper 18, and the powder P is 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 coating apparatus 100 shown in 3, the compounded powder P was supplied to the hopper 108, and the powder P was applied to the substrate 104 in an area of ​​100 [mm] × 50 [mm] from a screen 112 set to 300 mesh.

[0047] (3) Fixation and densification Using a flat press, the substrate 14 is pressed at 150°C and 5kN for 1 minute to fix the powder P and prepare an electrode. Following the same procedure, the substrate 104 is pressed with powder P to prepare an electrode.

[0048] (4) Measurement of electrode weight The fabricated electrodes were punched out in 12 places, and their weight was measured using an electronic balance. Table 1 below shows the calculated weight variations at 12 locations.

[0049] [Table 1]

[0050] The results in Table 1 show that applying the battery electrode material with the battery electrode material coating apparatus 10 according to the example reduces the weight variation during electrode fabrication compared to using the battery electrode material coating apparatus 100 of the comparative example. Since the weight of the electrode depends on the amount of powder P applied per unit area, it can be seen that the powder P can be applied more uniformly in the example than in the comparative example.

[0051] In this embodiment, as shown in Figure 1, the ultrasonic transducer 20 is connected to a portion of the hopper 18 below its vertical center, but the embodiment is not limited to this. For example, the ultrasonic transducer 20 may be connected to the vertical center of the hopper 18.

[0052] Alternatively, a structure using multiple ultrasonic transducers 20 may be used. 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 transport unit 12 includes a supply-side roller 12A and a recovery-side roller 12B, but it is not limited to this configuration, and other structures may be adopted as long as they are capable of transporting the base material 14. For example, if the base material is in the form of a sheet rather than a roll, a structure that transports the base material using a belt or the like may be used.

[0054] The following additional information is disclosed regarding the above embodiment.

[0055] (Note 1) A conveying unit for transporting conductive substrates, A hopper configured to contain powder and equipped with a conductive screen, A voltage application unit capable of applying voltage is provided between the conveying unit and the hopper. An ultrasonic transducer connected to the side wall of the hopper, A battery electrode material coating apparatus having the following features. (Note 2) The aforementioned screen is provided in the discharge hole of the hopper, in the battery electrode material coating apparatus as described in Appendix 1. (Note 3) The battery electrode material coating apparatus according to Appendix 1 or Appendix 2, wherein the ultrasonic transducer is connected to the hopper below the central portion in the vertical direction. (Note 4) The hopper is positioned with its longitudinal direction perpendicular to the direction in which the substrate is conveyed by the conveying unit. The ultrasonic transducer is connected to the central portion in the longitudinal direction of the hopper, as described in any one of the appendices 1 to 3, for a battery electrode material coating apparatus. [Explanation of symbols]

[0056] 10,30 Battery electrode material coating apparatus 12 Conveying section 14 Base material 16 Power supply (voltage application section) 18.32 hopper 18B, 32B screen 20 Ultrasonic transducers P powder

Claims

1. A conveying unit for transporting conductive substrates, A hopper comprising a main body which is configured to accommodate powder with openings at both the upper and lower ends and gradually narrows towards the bottom, and a conductive screen provided in the lower discharge hole of the main body, A voltage application unit capable of applying voltage is provided between the conveying unit and the hopper. An ultrasonic transducer connected to the side wall of the main body, It has, The transport unit is configured to include a supply-side roller and a recovery-side roller. The base material is wrapped around the supply-side roller and the recovery-side roller. The voltage application unit is configured to apply a voltage between the screen and the recovery roller in a battery electrode material coating apparatus.

2. The battery electrode material coating apparatus according to Claim 1, wherein the main body is arranged with its longitudinal direction perpendicular to the direction in which the substrate is transported by the transport unit, and its length along the transport direction is set to 10 mm or less.

3. The battery electrode material coating apparatus according to claim 1, wherein the ultrasonic transducer is connected to the main body below the central portion in the vertical direction.

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