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 configured to house a powder P; a conductive screen 17 disposed between the base material 14 transported by the transport part 12 and the hopper 18; a voltage application part 16 which can apply a voltage to an area between the transport part 12 and the screen 17; and an inclined plate 22 extending from the screen 17 in an oblique downward direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the device 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 electrode material coating device for a battery that can uniformly apply powder to an object to be coated.

Means for Solving the Problems

[0006] The electrode material coating device for a battery according to claim 1 includes a transport unit that transports a conductive substrate, a hopper configured to accommodate powder, a conductive screen disposed between the substrate transported by the transport unit and the hopper, a voltage application unit capable of applying a voltage between the transport unit and the screen, and an inclined plate extending obliquely downward from the screen. Furthermore, multiple inclined plates are provided for a single screen along the conveying direction of the substrate. .

[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 accommodate powder. Furthermore, a conductive screen is placed between the substrate being conveyed by the conveying unit and the hopper. A voltage application unit is configured to apply voltage between the conveying unit and the screen. As a result, a predetermined amount of powder is supplied from the hopper through the screen to the substrate conveyed by the conveying unit, thereby coating the substrate with powder. Here, an inclined plate extends diagonally downward from the screen. As a result, the powder that has passed through the screen is dispersed as it slides along the inclined plate, allowing for uniform coating of the powder on the substrate. Furthermore, because multiple inclined plates are provided, the powder can be uniformly applied to the substrate even when the screen is long.

[0008] The battery electrode material coating apparatus according to claim 2, in claim 1, wherein the inclined plate extends to the vicinity of the substrate being transported by the transport unit.

[0009] In the battery electrode material coating apparatus according to claim 2, since the inclined plate extends to the vicinity of the substrate, it is possible to suppress the scattering of powder that falls from the inclined plate.

[0012] Claim 3 The battery electrode material coating apparatus according to claim 1 is configured such that the inclined plate is set at an angle of 45 degrees or more and 80 degrees or less with respect to the screen.

[0013] Claim 3 In the battery electrode material coating apparatus relating to this, setting the angle of the inclined plate to 45 degrees or more relative to the screen can suppress the accumulation of powder on the inclined plate compared to the case where the inclination angle is less than 45 degrees. Furthermore, setting the angle of the inclined plate to 80 degrees or less relative to the screen can suppress the powder from falling without contacting the inclined plate compared to the case where the inclination angle is greater than 80 degrees.

[0014] Claim 4 The battery electrode material coating apparatus relating to claims 1 to 3In any one of the above, a frame holding the screen is provided below the hopper, and an ultrasonic transducer is connected to the side wall of the frame.

[0015] Claim 4 In the battery electrode material coating apparatus relating to this invention, a frame holding the screen is provided below the hopper. Since an ultrasonic transducer is connected to the side wall of the frame, ultrasonic vibrations can be applied to the powder passing through the screen. [Effects of the Invention]

[0016] 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]

[0017] [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 as a reference 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]

[0018] A battery electrode material coating apparatus 10 according to this embodiment will be described with reference to the drawings.

[0019] 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 frame 15, a screen 17, a hopper 18, a power supply 16 as a voltage application unit, an ultrasonic transducer 20, and an inclined plate 22.

[0020] The conveying unit 12 is configured to include a supply-side roller 12A and a recovery-side roller 12B. The supply-side roller 12A and the recovery-side roller 12B are each configured to rotate by the operation of a motor (not shown).

[0021] A conductive base material 14 is wound between the supply-side roller 12A and the recovery-side roller 12B. As the base material 14, a metal foil or the like is used. For example, a copper foil, an aluminum foil, or the like is used in a state of being wound in a roll shape.

[0022] Before the powder is applied, a pre-application base material 14A is wound around the supply-side roller 12A in a roll shape. After the powder is applied, an after-application base material 14C is wound around the recovery-side roller 12B in a roll shape. By operating a motor (not shown), the supply-side roller 12A and the recovery-side roller 12B rotate respectively, and the base material 14 is conveyed from the supply-side roller 12A to the recovery-side roller 12B. And the powder P is configured to be applied to the base material 14B being conveyed between the supply-side roller 12A and the recovery-side roller 12B.

[0023] Above the base material 14B being conveyed, a frame body 15 is provided. The frame body 15 is formed in a substantially box shape including a bottom wall 15A and side walls 15B, and is open at the top. Further, a screen 17 is held on the bottom wall 15A of the frame body 15, and the screen 17 is located below a hopper 18 described later. In other words, the screen 17 is disposed between the base material 14 conveyed by the conveying unit 12 and the hopper 18.

[0024] The screen 17 has conductivity and a predetermined pattern is formed thereon. For example, the screen 17 may be a conductive screen in which the patterned portion is formed of a mesh material. By passing the powder P onto the base material 14 through the screen 17, the powder P is applied onto the base material 14 in a desired pattern.

[0025] The mesh material for 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 wire, etc. may be used. The mesh size is also not particularly limited and may be changed as appropriate depending on the pattern.

[0026] A hopper 18 is positioned above the screen 17. The hopper 18 has openings at its upper and lower ends, and is shaped to gradually narrow towards the bottom. In this embodiment, the hopper 18 is positioned with its longitudinal direction perpendicular to the direction in which the substrate 14 is transported by the transport unit 12. That is, the hopper 18 is positioned with its longitudinal direction corresponding to the depth direction of the paper in Figure 1. For example, the length of the hopper 18 in the longitudinal direction may be slightly shorter than the width of the transported substrate 14.

[0027] Powder P is supplied from the supply hole at the upper end of the hopper 18. Powder P can be the active material and binder that constitute the electrode material. For example, in the case of a negative electrode material for a lithium-ion battery, a composite material of graphite, which is the active material, and a binder is used as powder P. The binder may be at least one material selected from, for example, polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HEP), styrene-butadiene rubber (SBR), carboxymethylcellulose (CMC), polyacrylic acid (PAA), polyamide-imide (PAI), and polyimide (PI).

[0028] Here, the side walls 15B of the frame 15 and the conveying section 12 are electrically connected to the power supply 16, and the power supply 16 is configured to apply a voltage between the screen 17 and the conveying section 12. When the powder passes through the screen 17 with the voltage applied, the mesh comes into contact with the powder P, and the powder P is charged.

[0029] An ultrasonic transducer 20 is connected to the side wall 15B of the frame 15. The ultrasonic transducer 20 is not particularly limited in structure or type, as long as it is a transducer capable of imparting ultrasonic vibrations to the powder in the hopper 18.

[0030] In this embodiment, as an example, the ultrasonic transducer 20 is connected to the lower end of the side wall 15B of the frame 15, and is configured to directly apply ultrasonic vibrations to the bottom wall 15A as well. Furthermore, from the viewpoint of applying 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.

[0031] An inclined plate 22 is attached to the screen 17. The inclined plate 22 extends diagonally downward from the lower surface of the screen 17, and in this embodiment, as an example, it is inclined in the transport direction as it moves from the screen 17 toward the base material 14 (downward).

[0032] In this 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 transport direction of the base material 14 and extend to the vicinity of the base material 14.

[0033] Furthermore, each of the three inclined plates 22 is set at an angle of 45 degrees or more and 80 degrees or less relative to the screen 17. In this embodiment, as an example, the three inclined plates 22 are set at an angle of 70 degrees relative to the screen 17. Note that the angle of the inclined plates 22 may be changed depending on the material of the powder being supplied.

[0034] (action) Next, the operation of the battery electrode material coating apparatus 10 according to this embodiment will be explained.

[0035] 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 accommodate powder P. Furthermore, a conductive screen 17 is placed between the substrate 14 conveyed by the conveying unit 12 and the hopper 18. A voltage can be applied between the conveying unit 12 and the screen 17. 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 via the screen 17, thereby coating the substrate 14 with powder P.

[0036] Furthermore, an inclined plate 22 is attached to the screen 17, and the inclined plate 22 extends diagonally downward from the screen 17. As a result, the powder P that passes through the screen 17 is dispersed as it slides along the inclined plate 22, allowing the powder P to be uniformly applied to the substrate 14.

[0037] In particular, in this embodiment, since the inclined plate 22 extends to the vicinity of the substrate 14B during transport, it is possible to suppress the scattering of powder P that falls from the inclined plate 22. In other words, it is possible to suppress uneven application of powder P.

[0038] Furthermore, in this embodiment, multiple 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 substrate 14.

[0039] Furthermore, in this embodiment, the angle of the inclined plate 22 is set to an angle of 45 degrees or more and 80 degrees or less with respect to the screen. This suppresses the accumulation of powder P on the inclined plate 22 compared to the case where the inclination angle of the inclined plate 22 is less than 45 degrees. In other words, the smaller the angle of the inclined plate 22, the less the powder P slides, and the more likely it is to accumulate on the inclined plate 22. In this embodiment, by setting the inclination angle of the inclined plate 22 to 45 degrees or more, the powder can slide well on the inclined plate 22 regardless of the type of powder being applied.

[0040] On the other hand, if the angle of the inclined plate 22 relative to the screen 17 is too large, the powder P may fall from the screen 17 onto the substrate 14 without contacting the inclined plate. Also, in order to ensure that the powder P makes contact with the inclined plate 22, the pitch between adjacent inclined plates 22 must be narrowed, which increases the number of inclined plates 22. In this embodiment, by setting the inclination angle of the inclined plate 22 to 80 degrees or less, it is possible to suppress the powder P from falling without contacting the inclined plate 22.

[0041] Furthermore, in this embodiment, an ultrasonic transducer 20 is connected to the side wall 15B of the frame 15, and is configured to apply ultrasonic vibrations to the screen 17. This eliminates the need to brush the powder P with a dedicated roller or squeegee, allowing the powder P to pass through the screen 17 in a dispersed state and slide along the inclined plate 22.

[0042] In particular, in this embodiment, since the ultrasonic transducer 20 is connected to the lower part of the side wall 15B of the frame 15, ultrasonic vibrations can be applied to the screen 17 in an adjustable manner.

[0043] In this embodiment, a structure in which the screen 17 is held in the frame 15 is adopted, but the invention is not limited to this. For example, as shown in Figure 2. reference You may adopt the example structure.

[0044] ( reference example) Figure 2 shows, reference This figure schematically shows the overall configuration of the battery electrode material coating apparatus 30 in this example. As shown in Figure 2, reference The battery electrode material coating apparatus 30 in this example differs from the embodiment in that it does not have a frame 15.

[0045] Book reference In this example, a hopper 32 is positioned above the conveying substrate 14B. The hopper 32 has openings at both its upper and lower ends and is shaped to gradually narrow towards the bottom, and is shorter in length along the conveying direction than the hopper 18 in the embodiment.

[0046] A screen 34 is provided at the lower end of the hopper 32. The screen 34 is attached to the discharge hole of the hopper 32 and is positioned between the conveyed substrate 14B and the hopper 32. An inclined plate 22 is attached to the screen 34, and the inclined plate 22 extends diagonally downward from the lower surface of the screen 34. In this embodiment, as an example, the screen 34 is inclined in the conveying direction as it moves towards the substrate 14 (downward), and one inclined plate 22 is attached.

[0047] An ultrasonic transducer 20 is connected to the side wall of the hopper 32. The ultrasonic transducer 20 is connected to the side wall of the hopper 32 below the central part in the vertical direction.

[0048] Book reference In this example, as in the embodiment, the inclined plate 22 extends downward from the screen 34, so that the powder P that has passed through the screen 34 is dispersed as it slides along the inclined plate 22, and the powder P can be uniformly applied to the substrate 14.

[0049] (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.

[0050] 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.

[0051] In the comparative example, a frame 110 is positioned below the hopper 108, and a conductive screen 112 is placed on the bottom wall 110A of this frame 110. Also 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.

[0052] Furthermore, in the comparative example structure, the ultrasonic transducer 20 is connected to the side wall 110B 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. Here, in the comparative example structure, the inclined plate 22 is not provided. Therefore, 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 then falls and is applied to the substrate 104 installed in the substrate holder 102.

[0053] The evaluation procedure is as follows:

[0054] (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%].

[0055] (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 17 set to 300 mesh. On the other hand, in the battery electrode material coating apparatus 100 shown in Figure 3, the composite 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.

[0056] (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.

[0057] (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.

[0058] [Table 1]

[0059] 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.

[0060] In this embodiment, as shown in Figure 1, the ultrasonic transducer 20 is connected to the side wall 15B of the frame 15, but the structure is not limited to this, and a structure without the ultrasonic transducer 20 may also be used.

[0061] Furthermore, in this embodiment, the ultrasonic transducer 20 is connected to the lower part of the side wall 15B of the frame 15, but the invention is not limited to this. For example, the ultrasonic transducer 20 may be connected to the central part of the side wall 15B in the vertical direction.

[0062] Furthermore, although three inclined plates 22 are provided in this embodiment, the invention is not limited to this, and the number and angle of the inclined plates 22 may be changed. For example, the number of inclined plates 22 may be increased and arranged so that adjacent inclined plates 22 overlap when viewed from above or below the screen 17.

[0063] Furthermore, although the angles of the three inclined plates 22 are the same in this embodiment, the invention is not limited to this, and the inclination angle may be changed for each inclined plate 22. For example, the angle of the inclined plate 22 further from the side wall 15B to which the ultrasonic transducer 20 is connected may be increased, and the angle of the inclined plate 22 closer to the side wall 15B to which the ultrasonic transducer 20 is connected may be decreased. By adjusting the angle of the inclined plates 22 in accordance with the attenuation of ultrasonic vibration, the same amount of powder P per unit time can be dropped from all inclined plates 22.

[0064] Furthermore, in this embodiment, the transport unit 12 is configured to include 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.

[0065] The following additional information is disclosed regarding the above embodiment.

[0066] (Note 1) A conveying unit for transporting conductive substrates, A hopper configured to contain powder, A conductive screen is placed between the substrate being transported by the transport unit and the hopper, A voltage application unit capable of applying voltage between the transport unit and the screen, An inclined plate extending diagonally downward from the aforementioned screen, A battery electrode material coating apparatus having the following features. (Note 2) The battery electrode material coating apparatus according to Appendix 1, wherein the inclined plate extends to the vicinity of the substrate being transported by the transport unit. (Note 3) The battery electrode material coating apparatus according to Appendix 1 or Appendix 2, wherein the inclined plates are provided in multiple locations along the conveying direction of the substrate. (Note 4) The battery electrode material coating apparatus according to any one of Appendix 1 to Appendix 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) A frame that holds the screen is provided below the hopper. A battery electrode material coating apparatus according to any one of the appendices 1 to 4, wherein an ultrasonic transducer is connected to the side wall of the frame. [Explanation of symbols]

[0067] 10, 30 Battery electrode material coating apparatus 12 Conveying section 14 Base material 15 Frame 15B Side wall 16 Power supply (voltage application section) 17,34 screens 18.32 hopper 20 Ultrasonic transducers 22 Inclined plate P powder

Claims

1. A conveying unit for transporting conductive substrates, A hopper configured to contain powder, A conductive screen is placed between the substrate being transported by the transport unit and the hopper, A voltage application unit capable of applying voltage between the transport unit and the screen, An inclined plate extending diagonally downward from the aforementioned screen, It has, The aforementioned inclined plates are provided in multiple locations along the conveying direction of the substrate for a single screen in a battery electrode material coating apparatus.

2. The battery electrode material coating apparatus according to claim 1, wherein the inclined plate extends to the vicinity of the substrate being transported by the transport unit.

3. The battery electrode material coating apparatus according to claim 1, wherein the inclined plate is set at an angle of 45 degrees or more and 80 degrees or less with respect to the screen.

4. A frame that holds the screen is provided below the hopper. A battery electrode material coating apparatus according to any one of claims 1 to 3, wherein an ultrasonic transducer is connected to the side wall of the frame.

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