WO2022210965A1

WO2022210965A1 - Battery electrode manufacturing device and battery electrode manufacturing method

Info

Publication number: WO2022210965A1
Application number: PCT/JP2022/016269
Authority: WO
Inventors: 英明堀江; 健一郎榎; 勇輔中嶋
Original assignee: Ａｐｂ株式会社
Priority date: 2021-03-31
Filing date: 2022-03-30
Publication date: 2022-10-06
Also published as: JP2022156610A

Abstract

This battery electrode manufacturing device (1) comprises: a chamber (2) in which the pressure in an interior space (20a) is less than atmospheric pressure, said chamber (2) having a slit (20s) via which the interior space and an exterior space (20b) communicate; a feeding mechanism (3) that feeds a pulverulent active material (25) to a strip-form base film (23) that is conveyed through the slit from the exterior space to the interior space, said feeding mechanism (3) being positioned in the interior space; and a tension mechanism (4) having exterior rollers (41) positioned in the exterior space, and interior rollers (42) positioned between the slit and the feeding mechanism in the interior space, tension being applied to the base film (23) by the exterior rollers and the interior rollers.

Description

Battery electrode manufacturing apparatus and battery electrode manufacturing method

The present invention relates to a battery electrode manufacturing apparatus and a battery electrode manufacturing method.

Conventionally, there are technologies for transporting long components. Patent Literature 1 discloses a surface treatment apparatus for a long substrate that is transported along a roll-to-roll transport path within a vacuum chamber. Also, conventionally, there is a technique for manufacturing a lithium-ion battery. Patent Document 2 discloses a technique for manufacturing a battery structure having a first current collector, a positive electrode active material, a separator, a negative electrode active material, and a second current collector. The manufacturing process described in Patent Document 2 includes a step of supplying a positive electrode active material or a negative electrode active material onto a current collector sheet.

Japanese Patent Application Laid-Open No. 2018-031040 Japanese Patent No. 6633866

Here, there is an idea that the supply of the active material to the base film in the manufacturing process of the lithium-ion battery is performed in a chamber whose internal space is reduced below atmospheric pressure. According to this idea, it is possible to prevent impurities from entering the chamber and improve the quality of the battery electrode.

In order to improve the production efficiency when producing a battery electrode in the chamber, the base film is continuously supplied from outside the chamber (under normal pressure environment) into the chamber (under reduced pressure environment), It is necessary to supply the active material to the base film introduced inside. The present inventors have found a configuration in which a slit is provided in a chamber whose internal space is reduced below the atmospheric pressure, and the substrate film is transported from the external space to the internal space of the chamber via the slit.

However, according to the configuration found by the present inventors, when the base film is transported from the outer space toward the inner space of the chamber, the air flows into the depressurized chamber through the slit, thereby The material film may vibrate (eg, due to generated eddies, etc.). Patent Document 1 merely discloses a technique for transporting a long substrate along a roll-to-roll transport path in a vacuum chamber, and transports the long substrate from the external space to the internal space of the chamber. When doing so, it is desired to solve the problem of suppressing the vibration of the base material.

An object of the present invention is to provide a battery electrode manufacturing apparatus and a battery electrode capable of suppressing vibration of a base film transported into a chamber interior space reduced from atmospheric pressure and stably transporting the base film. It is to provide a manufacturing method.

The battery electrode manufacturing apparatus of the present invention comprises a chamber having an internal space that is reduced in pressure from atmospheric pressure and having a slit that communicates the internal space and the external space; A supply mechanism for supplying a powdery active material to a belt-shaped base film conveyed from the external space to the internal space by a feeding mechanism, an external roller arranged in the external space, and the slit in the internal space and an internal roller disposed between the supply mechanism and a tension mechanism for applying tension to the base film by the external roller and the internal roller. .

The battery electrode manufacturing apparatus according to the present invention has the effect of suppressing the vibration of the base film transported into the inner space of the chamber whose pressure is reduced below the atmospheric pressure, and stably transporting the base film.

FIG. 1 is a schematic configuration diagram of a lithium-ion cell. FIG. 2 is a schematic configuration diagram of the battery electrode manufacturing apparatus according to the embodiment. Drawing 3 is a perspective view of a member sheet manufacturing device concerning an embodiment. FIG. 4 is a diagram showing a tension mechanism according to the embodiment. FIG. 5 is an explanatory diagram of a Karman vortex. FIG. 6 is a diagram showing a tension mechanism according to a first modified example of the embodiment; FIG. 7 is a diagram showing a tension mechanism according to a first modified example of the embodiment; FIG. 8 is a diagram showing a tension mechanism according to a second modified example of the embodiment;

A battery electrode manufacturing apparatus and a battery electrode manufacturing method according to embodiments of the present invention will be described in detail below with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, components in the following embodiments include those that can be easily assumed by those skilled in the art or substantially the same components.

[Embodiment]
An embodiment will be described with reference to FIGS. 1 to 5. FIG. The present embodiment relates to a battery electrode manufacturing apparatus and a battery electrode manufacturing method.

(Battery pack)
The battery electrode manufacturing apparatus and battery electrode manufacturing method of the present embodiment are applied, for example, to the manufacture of lithium ion batteries. Lithium ion batteries are used in the form of assembled batteries in which a plurality of lithium ion single cells (battery cells) are combined into a module, or in the form of battery packs in which a plurality of such assembled batteries are combined to adjust the voltage and capacity. The lithium ion battery (battery cell, single cell, single battery unit) in this specification refers to a secondary battery that uses lithium ions as charge carriers and is charged and discharged by the movement of lithium ions between the positive and negative electrodes. . The lithium ion battery (secondary battery) includes a battery using a liquid material for the electrolyte and a battery using a solid material for the electrolyte (so-called all-solid-state battery). In addition, the lithium ion battery in the present embodiment includes a battery having a metal foil (metal current collector foil) as a current collector, and is composed of a resin to which a conductive material is added instead of the metal foil, a so-called resin current collector. Including a battery with a body. When the resin current collector is used as a resin current collector for a bipolar electrode, which will be described later, a positive electrode is formed on one surface of the resin current collector and a negative electrode is formed on the other surface to form a bipolar electrode. may be configured. In addition, the lithium ion battery in the present embodiment includes those in which the positive electrode or negative electrode active material or the like is applied to the positive electrode current collector or the negative electrode current collector using a binder to configure the electrode, and in the case of a bipolar battery, is a bipolar electrode having a positive electrode layer formed by applying a positive electrode active material or the like using a binder to one surface of a current collector, and a negative electrode layer formed by applying a negative electrode active material or the like using a binder to the opposite surface of the current collector. including those that consist of Moreover, the method of stacking the assembled battery is arbitrary. As an example of the lamination method, a unit cell having a positive electrode resin current collector on the first surface and a negative electrode resin current collector on the second surface is arranged such that the first surface (positive electrode side) and the first surface (positive electrode side) of a pair of adjacent unit cells are stacked. A laminated battery may be formed by laminating a plurality of layers in series so that the two surfaces (negative electrode side) are adjacent to each other. As another example, a single cell in which a positive electrode layer is provided on one side of a single resin current collector and a negative electrode layer is provided on the other side of the resin current collector may be laminated with an electrolyte layer interposed between them to form a laminated battery. good.

(Lithium-ion cell)
Next, a lithium-ion cell will be described. For example, a lithium-ion single battery has a positive electrode current collector layer, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode current collector layer laminated in this order, and the positive electrode current collector layer and the negative electrode current collector layer are laminated. as the outermost layer, and an electrolyte is enclosed by sealing the outer peripheries of the positive electrode active material layer and the negative electrode active material layer.

FIG. 1 is a schematic configuration diagram of a lithium-ion cell 10. FIG. In the lithium-ion single cell 10, a positive electrode current collector layer 111, a positive electrode active material layer 113, a separator 130, a negative electrode active material layer 123, and a negative electrode current collector layer 121 are laminated in the order shown in FIG. That is, the positive electrode current collector layer 111 and the negative electrode current collector layer 121 are arranged as the outermost layers. In addition, the frame 140 seals the edges of the positive electrode current collector layer 111 and the negative electrode current collector layer 121 (peripheries of the positive electrode active material layer 113 and the negative electrode active material layer 123). An electrolytic solution is enclosed in the positive electrode active material layer 113 and the negative electrode active material layer 123 .

(Positive electrode current collector)
As the positive electrode current collector layer 111, a current collector used in a known lithium-ion single battery can be used. For example, a known metal current collector and a resin current collector ( resin current collectors described in JP-A-2012-150905 and WO 2015/005116, etc.) can be used. The positive electrode current collector layer 111 is preferably a resin current collector from the viewpoint of battery characteristics and the like.

Although the thickness of the positive electrode current collector layer 111 is not particularly limited, it is preferably 5 to 150 μm. When a plurality of resin current collectors are laminated and used as a positive electrode current collector, the total thickness after lamination is preferably 5 to 150 μm.

The positive electrode current collector layer 111 can be obtained, for example, by molding a conductive resin composition obtained by melt-kneading a matrix resin, a conductive filler, and a dispersing agent for a filler used if necessary into a film by a known method. can be done.

(Positive electrode active material)
The positive electrode active material layer 113 is preferably a non-bound mixture containing a positive electrode active material. Here, the non-bound body means that the position of the positive electrode active material is not fixed in the positive electrode active material layer, and the positive electrode active materials and the positive electrode active materials and the positive electrode active material and the current collector are irreversibly means not fixed. When the positive electrode active material layer 113 is a non-bound body, the positive electrode active materials are not irreversibly fixed to each other, so that the interface between the positive electrode active materials can be separated without mechanically destroying them. Even when stress is applied to the substance layer 113, the positive electrode active material moves, which is preferable because the positive electrode active material layer 113 can be prevented from being broken. The positive electrode active material layer 113, which is a non-binder, can be obtained by a method such as making the positive electrode active material layer 113 containing a positive electrode active material and an electrolytic solution but not containing a binder. can.

Examples of the positive electrode active material include, but are not limited to, a composite oxide of lithium and a transition metal, a composite oxide containing two transition metal elements, and a composite oxide containing three or more metal elements. .

The positive electrode active material layer 113 may contain an electrolytic solution containing an electrolyte and a non-aqueous solvent. As the electrolyte, those used in known electrolytic solutions can be used.

As the non-aqueous solvent, those used in known electrolytic solutions (for example, phosphate esters, nitrile compounds, etc., and mixtures thereof, etc.) can be used. For example, a mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) or a mixture of ethylene carbonate (EC) and propylene carbonate (PC) can be used.

Although the thickness of the positive electrode active material layer 113 is not particularly limited, it is preferably 150 to 600 μm, more preferably 200 to 450 μm, from the viewpoint of battery performance.

(Negative electrode current collector)
As the negative electrode current collector layer 121, one having the same structure as that described for the positive electrode current collector layer 111 can be appropriately selected and used, and can be obtained by a similar method. The negative electrode current collector layer 121 is preferably a resin current collector from the viewpoint of battery characteristics and the like. Although the thickness of the negative electrode current collector layer 121 is not particularly limited, it is preferably 5 to 150 μm.

(Negative electrode active material)
The negative electrode active material layer 123 is preferably a non-bound mixture containing a negative electrode active material. The reason why the negative electrode active material layer is preferably a non-binder, and the reason why the positive electrode active material layer 113 is preferably a non-binder is the method for obtaining the negative electrode active material layer 123 which is a non-binder. , and the method for obtaining the positive electrode active material layer 113 which is a non-binder.

As the negative electrode active material, for example, a carbon-based material, a silicon-based material, a mixture thereof, or the like can be used, but is not particularly limited.

The negative electrode active material layer 123 contains an electrolytic solution containing an electrolyte and a non-aqueous solvent. As for the composition of the electrolytic solution, an electrolytic solution similar to the electrolytic solution contained in the positive electrode active material layer 113 can be preferably used.

Although the thickness of the negative electrode active material layer 123 is not particularly limited, it is preferably 150 to 600 μm, more preferably 200 to 450 μm, from the viewpoint of battery performance.

(separator)
Examples of the separator 130 include a porous film made of polyethylene or polypropylene, but the separator is not particularly limited. As the separator, a sulfide-based or oxide-based inorganic solid electrolyte, or a polymer-based organic solid electrolyte can be used. By applying a solid electrolyte, an all-solid battery can be constructed.

(frame body)
The lithium-ion unit cell 10 has a structure in which an electrolytic solution is enclosed by sealing the edges of the positive electrode current collector layer 111 and the negative electrode current collector layer 121 with a frame 140 . The frame 140 is arranged between the positive electrode current collector layer 111 and the negative electrode current collector layer 121 and has a function of sealing the outer circumferences of the positive electrode active material layer 113 , the negative electrode active material layer 123 and the separator 130 .

Note that FIG. 1 shows a case where a part of the separator 130 is configured to enter the frame 140 . That is, in FIG. 1 , the width of the separator 130 is larger than that of the positive electrode active material layer 113 and the negative electrode active material layer 123 surrounded by the frame 140 , and a part of the separator 130 bites into the frame 140 . . However, the embodiment is not limited to this, and for example, the positive electrode active material layer 113, the negative electrode active material layer 123, and the separator 130 may have the same width in the horizontal direction of FIG. Further, the frame 140 shown in FIG. 1 may be manufactured integrally, or may be manufactured, for example, by separately manufacturing a frame on the positive electrode side and a frame on the negative electrode side and combining them.

The frame 140 is not particularly limited as long as it is made of a material that is durable against the electrolytic solution, but a polymer material is preferred, and a thermosetting polymer material is more preferred. Specifically, epoxy-based resins, polyolefin-based resins, polyurethane-based resins, polyvinylidene fluoride resins, and the like can be mentioned, and epoxy-based resins are preferred because of their high durability and ease of handling.

The frame 140 is a frame-shaped member. In the process of manufacturing the lithium-ion single cell 10 , the frame 140 is attached to either the positive electrode current collector layer 111 or the negative electrode current collector layer 121 . In the following description, when the positive electrode side and the negative electrode side are not particularly distinguished, the positive electrode current collector layer 111 and the negative electrode current collector layer 121 are also simply referred to as current collectors. That is, the frame 140 is attached to the current collector on the positive electrode side or the negative electrode side. Further, after forming the positive electrode active material layer 113, the negative electrode active material layer 123, the separator 130, and the like inside the frame 140, the other current collector is further formed, whereby the lithium ion single battery 10 can be manufactured. .

As shown in FIG. 2, the electrode manufacturing system 100 according to this embodiment has a battery electrode manufacturing apparatus 1 and a film supply apparatus 30. As shown in FIG. The film supply device 30 is a device that supplies the strip-shaped base film 23 to the battery electrode manufacturing apparatus 1 . The film supply device 30 feeds out the base film 23 wound on a roll, for example. Examples of the strip-shaped base film 23 include current collectors, separators, and transfer films. When the base film 23 is a transfer film, the active material layer (electrode composition layer) formed on the transfer film is transferred onto the current collector, for example, to obtain a lithium ion battery electrode. be able to.

As shown in FIG. 2 , the battery electrode manufacturing apparatus 1 has a chamber 2 , a supply mechanism 3 , a tension mechanism 4 , a roll press 5 , a tank 6 and a frame supply device 8 . The chamber 2 is a room whose inside can be kept in a state of being reduced in pressure below atmospheric pressure. The chamber 2 has a housing 20 forming a closed space. The internal space 20a of the chamber 2 is decompressed below atmospheric pressure by a decompression pump (not shown). The pressure in the internal ^space ^20a may be any value as long as it is reduced below the atmospheric pressure. It may be adjusted to a high vacuum environment of 1×10 ⁻⁶ to 1×10 ⁻⁷ Pa, or an ultrahigh vacuum of 10 ⁻⁸ to 10 ⁻⁹ Pa. It may be a level of extreme high vacuum. The standard atmospheric pressure is approximately 1013 hPa (approximately 10 ⁵ Pa).

The housing 20 has slits 20s. 20 s of slits are arrange|positioned at one side wall 20w which the housing|casing 20 has. The illustrated slit 20 s penetrates the side wall 20 w along the transport direction X of the base film 23 . The transport direction X is a direction perpendicular to the vertical direction Z, for example. The shape of the slit 20s when the side wall 20w is viewed from the front is, for example, a rectangle. The base film 23 is conveyed from the outer space 20b of the housing 20 to the inner space 20a through the slit 20s. The width of the slit 20 s is slightly larger than the width of the base film 23 . Also, the height of the slit 20 s is slightly larger than the thickness of the base film 23 .

The frame supply device 8 is arranged in the internal space 20 a of the housing 20 . The illustrated frame feeder 8 is arranged between the side wall 20w and the feeding mechanism 3 . The frame supply device 8 supplies the frame 140 to the base film 23 being conveyed, and installs the frame 140 on the base film 23 . The frame 140 is transported along the transport direction X together with the base film 23 .

The supply mechanism 3 is arranged in the internal space 20 a of the housing 20 . The supply mechanism 3 supplies powdery active material 25 to the transported base film 23 . More specifically, the supply mechanism 3 supplies the active material 25 to the frame 140 installed on the base film 23 . The powdery active material 25 is stored in the tank 6 arranged in the external space 20b. The supply mechanism 3 fills the inside of the frame 140 with the active material 25 sent from the tank 6 and applies the active material 25 to the base film 23 .

The roll press 5 is arranged downstream of the supply mechanism 3 in the transport direction X. The roll press 5 press-molds the active material 25 applied to the base film 23 . The roll press 5 has a role of fixing the active material 25 to the strip-shaped base film 23 . In the battery electrode manufacturing apparatus 1 of the present embodiment, the steps of applying the active material 25 and press molding are performed in the reduced pressure internal space 20a. As a result, it is possible to prevent air from remaining inside the active material 25 and prevent expansion and deformation of the active material 25 after the end of pressing.

Note that the frame supply device 8 may install the frame 140 on the base film 23 on the downstream side of the supply mechanism 3 . For example, the frame supply device 8 may be arranged between the supply mechanism 3 and the roll press 5, may be arranged downstream of the roll press 5, or may be arranged downstream of the roll press 5. may be arranged outside the housing 2 . Further, the battery electrode manufacturing apparatus or the battery electrode manufacturing method according to the present embodiment may not include the frame supply device or the frame supply step. For example, when a transfer film is used as the base film 23, after the active material layer (electrode composition layer) is formed on the transfer film (that is, after the electrode manufacturing process is finished), A frame may be arranged on the current collector to which the electrode composition layer has been transferred, or on the current collector before the electrode composition layer has been transferred.

Instead of supplying the frame 140 to the base film 23 inside the housing 2 , the frame 140 may be installed on the base film 23 outside the housing 2 . In this case, instead of the film supply device 30, a member sheet manufacturing device 32 shown in FIG. 3 may be used. The member sheet manufacturing device 32 is a device that manufactures the member sheet 24 by sequentially transferring a plurality of frames 140 onto the strip-shaped base film 23 . As shown in FIG. 3 , the member sheet manufacturing device 32 has a transfer device 322 . The transfer device 322 is a device that transfers the frame 140 of the transfer sheet 22 onto the strip-shaped base film 23 . The transfer sheet 22 is a sheet in which a plurality of frames 140 are continuously arranged with respect to the film 21 . A plurality of frames 140 are crimped to the film 21 . The member sheet manufacturing apparatus 32 pulls out the transfer sheet 22 from the roll 22 ′ and transfers the frame 140 of the transfer sheet 22 to the base film 23 .

The transfer device 322 has a transfer mechanism 3221 and a separation mechanism 3222. The transfer mechanism 3221 presses the transfer sheet 22 and the strip-shaped base film 23 together. For example, the transfer mechanism 3221 is a press roll that sandwiches and presses the transfer sheet 22 and strip-shaped base film 23 , and adheres the frame 140 of the transfer sheet 22 to the strip-shaped base film 23 . The base film 23 is transported at a predetermined transport speed by the transport rollers of the battery electrode manufacturing apparatus 1 . The member sheet manufacturing apparatus 32 presses the frame 140 to the base film 23 by the transfer mechanism 3221 while running the transfer sheet 22 in parallel with the base film 23 at the same speed.

The separation mechanism 3222 separates the frame 140 crimped to the base film 23 from the film 21 . That is, the separation mechanism 3222 generates the member sheet 24 by peeling the film 21 from the frame 140 . The separation mechanism 3222 may wind the film 21 separated from the frame 140 into a roll as shown in FIG. The base film 23 to which the frame 140 is attached is transported into the housing 2 through the slit 20s.

The tension mechanism 4 applies tension to the base film 23 . As shown in FIG. 2 , the tension mechanism 4 has an outer roller 41 and an inner roller 42 . The external roller 41 is arranged in the external space 20 b of the housing 20 . The internal roller 42 is arranged in the internal space 20 a of the housing 20 . The position of the internal roller 42 in the internal space 20a is the position between the slit 20s and the supply mechanism 3 in the transport direction X. As shown in FIG. That is, the internal roller 42 is positioned upstream in the transport direction X with respect to the supply mechanism 3 .

The outer roller 41, the slit 20s, and the inner roller 42 are arranged linearly along the transport direction X. With such an arrangement, the tension Ft can be applied to the base film 23 along the straight transport path along the transport direction X. As shown in FIG.

As shown in FIG. 4, the external roller 41 has a first roller 41a and a second roller 41b. The first roller 41a is arranged above the conveying path of the base film 23, and the second roller 41b is arranged below the conveying path. The external rollers 41 sandwich the base film 23 between the first roller 41a and the second roller 41b. In the illustrated outer roller 41, the outer diameter of the first roller 41a and the outer diameter of the second roller 41b are equal. The external roller 41 is, for example, a brake roller. That is, the external roller 41 is configured to apply a braking force Fb in a direction opposite to the transport direction X to the base film 23 . For example, the outer roller 41 has rotational resistance corresponding to the braking force Fb.

The internal roller 42 has a pressing roller 42a, a driving roller 42b, and a motor 42c. In the illustrated internal rollers 42, the pressure roller 42a is arranged above the conveying path of the base film 23, and the driving roller 42b is arranged below the conveying path. The drive roller 42b is a member such as a capstan, and is, for example, a cylindrical metal shaft. The motor 42c is a rotary motor that rotates the drive roller 42b. The driving roller 42b may be connected to the output shaft of the motor 42c, or may be connected to the output shaft of the motor 42c via a reduction mechanism. The pressing roller 42a is a roller that presses the base film 23 toward the driving roller 42b. The outer diameter of the pressing roller 42a is larger than the outer diameter of the drive roller 42b. The inner roller 42 may have a spring that biases the pressure roller 42a toward the drive roller 42b.

The driving roller 42 b applies a driving force Ff along the transport direction X to the base film 23 . The internal roller 42 functions as a transport roller that transports the base film 23 . The tension mechanism 4 applies tension Ft to the base film 23 with the driving force Ff and the braking force Fb. The tension Ft is generated in the target portion 24m of the base film 23 located between the outer roller 41 and the inner roller 42 . As described below, the battery electrode manufacturing apparatus 1 of the present embodiment can suppress vibration of the base film 23 caused by Karman vortices and the like.

FIG. 5 shows the air flow Af flowing from the outer space 20b of the housing 20 to the inner space 20a. The air flow Af is caused by the pressure difference between the outer space 20b and the inner space 20a. The atmospheric pressure of the external space 20b is, for example, the atmospheric pressure. The air in the outer space 20b enters the inner space 20a along the transport direction X through the slits 20s. A boundary layer BL is formed along the wall surface of the slit 20s in the slit 20s.

Further, a Karman vortex Kv is generated on the downstream side in the transport direction X of the slit 20s. The Karman vortices Kv are alternately generated above and below the base film 23 . A first vortex line VL<b>1 is generated above the base film 23 , and a second vortex line VL<b>2 is generated below the base film 23 . The battery electrode manufacturing apparatus 1 of the present embodiment can suppress the vibration of the base film 23 due to the Karman vortices Kv by the tension Ft. The tension mechanism 4 suppresses vibration of the base film 23 by applying tension Ft to the base film 23 . For example, the tension Ft can make the amplitude of the base film 23 in the vertical direction Z smaller than when the tension Ft is not applied to the base film 23 .

Also, the tension mechanism 4 can suppress the propagation of vibration in the base film 23 . For example, the internal rollers 42 can absorb vibrations generated in the target portion 24m at the internal rollers 42 . As a configuration for absorbing vibrations, for example, the pressing roller 42a may be made of elastic resin such as rubber. The internal roller 42 suppresses the vibration of the target portion 24m from propagating to the downstream side of the internal roller 42 . In addition, the external roller 41 suppresses the vibration of the target portion 24m from propagating upstream of the external roller 41 .

The tension mechanism 4 preferably applies tension Ft so as to shift the natural frequency ν of the target portion 24m from the vibration frequency fk of the Karman vortices Kv. The vibration frequency fk of the Karman vortex Kv is, for example, a frequency corresponding to the period of the Karman vortex Kv. The vibration frequency fk may be obtained theoretically or experimentally. The vibration frequency fk is, for example, the pressure difference between the external space 20b and the internal space 20a, the cross-sectional shape of the slit 20s, the length of the slit 20s along the transport direction X, the roughness of the wall surface of the slit 20s, and the thickness of the base film 23. It may be calculated based on the thickness or the like.

The natural frequency ν of the target portion 24m can be adjusted by the length Lx of the target portion 24m along the transport direction X and the magnitude of the tension Ft. The tension mechanism 4 of this embodiment is configured to shift the natural frequency ν with respect to the vibration frequency fk. Further, the tension mechanism 4 is configured to shift a multiple of the natural frequency ν with respect to the vibration frequency fk. Therefore, the battery electrode manufacturing apparatus 1 of the present embodiment can suitably suppress the occurrence of resonance of the base film 23 due to the Karman vortices Kv.

As described above, the battery electrode manufacturing apparatus 1 according to this embodiment has the chamber 2 having the slit 20s, the supply mechanism 3, and the tension mechanism 4. The internal space 20a of the chamber 2 is evacuated below the atmospheric pressure. The slit 20s communicates the internal space 20a and the external space 20b of the chamber 2 . The supply mechanism 3 is arranged in the internal space 20a. The supply mechanism 3 supplies the powdery active material 25 to the belt-like base film 23 conveyed from the external space 20b to the internal space 20a through the slit 20s. The base film 23 is, for example, a current collector, but is not limited to this, and may be a separator, a transfer film, or the like. According to the configuration in which the substrate film 23 is continuously supplied from the external space 20b to the internal space 20a of the chamber 2 through the slit 20s as in the present embodiment, the production efficiency of the battery electrode can be improved.

The tension mechanism 4 has an external roller 41 arranged in the external space 20b and an internal roller 42 arranged between the slit 20s and the supply mechanism 3 in the internal space 20a. The tension mechanism 4 applies tension Ft to the base film 23 with the external roller 41 and the internal roller 42 . That is, the tension mechanism 4 increases the tension of the base film 23 as compared with the case without the tension mechanism 4 . By applying the tension Ft, the battery electrode manufacturing apparatus 1 of the present embodiment can suppress the vibration of the base film 23 that is transported to the inner space of the chamber whose pressure is reduced below the atmospheric pressure.

The battery electrode manufacturing apparatus 1 according to the present embodiment can stabilize the transport speed of the base film 23 by suppressing the vibration of the base film 23 . That is, the battery electrode manufacturing apparatus 1 can stably transport the base film 23 . Therefore, the battery electrode manufacturing apparatus 1 according to the present embodiment can improve the stability of the supplying process of supplying the active material 25 to the base film 23 .

The outer roller 41 and the inner roller 42 of this embodiment each have a roller pair that sandwiches the base film 23 . The external rollers 41 have a first roller 41a and a second roller 41b that sandwich the base film 23 therebetween. The internal roller 42 has a pressure roller 42a and a drive roller 42b that sandwich the base film 23 therebetween. By sandwiching the substrate film 23 between the outer roller 41 and the inner roller 42 by the pair of rollers, it is possible to apply a desired tension Ft while suppressing an increase in the size of the tension mechanism 4 .

The internal roller 42 of this embodiment has a driving roller 42b that applies a driving force Ff in the transport direction X to the base film 23. The external roller 41 applies a braking force Fb in a direction opposite to the conveying direction X to the base film 23 . With such a configuration, the internal roller 42 can function as a transport roller that transports the base film 23 .

The tension mechanism 4 of this embodiment is based on the tension Ft that makes the natural frequency ν of the base film 23 between the outer roller 41 and the inner roller 42 different from the vibration frequency fk caused by the Karman vortices Kv generated in the slit 20s. It is added to the material film 23 . Therefore, vibration of the base film 23 between the outer roller 41 and the inner roller 42 is effectively suppressed.

The battery electrode manufacturing method according to the present embodiment has a step of applying tension and a step of supplying. In the step of applying the tension, the tension Ft is applied to the strip-shaped base film 23 conveyed through the slits 20s of the chamber 2 into the internal space 20a of the chamber 2 . The internal space 20a of the chamber 2 is pressure-reduced below atmospheric pressure. In the supplying step, the powdery active material 25 is supplied to the base film 23 in the internal space 20a.

In the step of applying tension, tension Ft is applied to the base film 23 by the external roller 41 arranged in the external space 20b of the chamber 2 and the internal roller 42 arranged in the internal space 20a. In the supplying step, the active material 25 is supplied to the base film 23 after passing through the internal rollers 42 . The method for manufacturing a battery electrode according to the present embodiment suppresses the vibration of the base film 23 that passes through the slit 20s and is conveyed to the inner space of the chamber whose pressure is reduced below the atmospheric pressure, and stabilizes the base film 23. can be transported.

[First modification of the embodiment]
A first modification of the embodiment will be described. FIG. 6 is a diagram showing a tension mechanism according to a first modified example of the embodiment; The tension mechanism 4 shown in FIG. 6 differs from the tension mechanism 4 of the above embodiment in the configuration of the internal rollers 42 . The internal rollers 42 shown in FIG. 6 have a first roller 42d and a second roller 42e. The internal rollers 42 sandwich the base film 23 between the first roller 42d and the second roller 42e. In the illustrated inner roller 42, the outer diameters of the first roller 42d and the second roller 42e are equal.

In the internal rollers 42, either the first roller 42d or the second roller 42e may be a driving roller. For example, the first roller 42d may act as a driving roller to apply the driving force Ff to the base film 23. FIG. In this case, the second roller 42e may be a driven roller.

In the tension mechanism 4 of the first modified example, both the outer roller 41 and the inner roller 42 may be brake rollers, as shown in FIG. In this case, it is desirable that the transport roller 7 for transporting the base film 23 is provided on the downstream side in the transport direction X of the tension mechanism 4 . The external roller 41 applies a braking force Fb1 to the base film 23 and the internal roller 42 applies a braking force Fb2 to the base film 23 . The braking force Fb1 by the outer roller 41 is made larger than the braking force Fb2 by the inner roller 42 .

The tension mechanism 4 shown in FIG. 7 applies tension Ft1 to the target portion 24m. The tension mechanism 4 can further apply tension Ft2 to the downstream side in the transport direction X of the internal roller 42 . The tension Ft2 applied to the downstream side is, for example, smaller than the tension Ft1 applied to the target portion 24m.

[Second Modification of Embodiment]
A second modification of the embodiment will be described. FIG. 8 is a diagram showing a tension mechanism according to a second modified example of the embodiment; The tension mechanism 4 shown in FIG. 8 differs from the tension mechanism 4 of the first modified example in the configuration of the external roller 41 .

The external rollers 41 shown in FIG. 8 have a first roller 41c, a second roller 41d, and a third roller 41e. The external rollers 41 meander the base film 23 with the first roller 41c, the second roller 41d, and the third roller 41e. The first roller 41c and the third roller 41e are arranged on an extension line of the slit 20s along the transport direction X. The position of the second roller 41d in the vertical direction Z is shifted with respect to the two

rollers

41c and 41e.

The external roller 41 is configured, for example, so that the contact angle of the base film 23 with respect to the first roller 41c and the third roller 41e is 90 degrees, and the contact angle of the base film 23 with respect to the second roller 41d is 180 degrees. be. The tension mechanism 4 applies a driving force Ff to the base film 23 by, for example, the internal rollers 42 . The external roller 41 generates tension Ft in the target portion 24m of the base film 23 by causing the base film 23 to meander. Note that the tension mechanism 4 may have a spring arranged on the second roller 41d. In this case, the tension mechanism 4 can adjust the magnitude of the tension Ft by the spring of the second roller 41d.

[Third modification of the embodiment]
A third modification of the embodiment will be described. In the above embodiments and modifications, both the outer roller 41 and the inner roller 42 may have drive rollers.

The contents disclosed in the above embodiments and modifications can be executed in combination as appropriate.

Claims

a chamber having an internal space reduced in pressure below atmospheric pressure and having a slit communicating between the internal space and the external space;
a supply mechanism arranged in the internal space for supplying a powdery active material to a strip-shaped base film conveyed from the external space to the internal space through the slit;
an external roller arranged in the external space; and an internal roller arranged between the slit and the supply mechanism in the internal space, wherein the external roller and the internal roller move against the base film. a tension mechanism that applies tension to the
Battery electrode manufacturing equipment.
The battery electrode manufacturing apparatus according to claim 1, wherein the outer roller and the inner roller each have a roller pair that sandwiches the base film.
The internal roller has a driving roller that applies a driving force in the conveying direction to the base film,
The battery electrode manufacturing apparatus according to claim 1 or 2, wherein the external roller applies a braking force in a direction opposite to the conveying direction to the base film.
The tension mechanism applies a tension to the base film that makes the natural frequency of the base film between the outer roller and the inner roller different from the vibration frequency due to Karman vortices generated in the slit. The battery electrode manufacturing apparatus according to any one of claims 1 to 3.
a step of applying tension to a strip-shaped base film conveyed through a slit of the chamber into the inner space of the chamber, which is reduced in pressure below atmospheric pressure;
a step of supplying a powdery active material to the base film in the internal space;
including
In the step of applying tension, tension is applied to the base film by an external roller arranged in the external space of the chamber and an internal roller arranged in the internal space,
The method for manufacturing a battery electrode, wherein in the supplying step, the active material is supplied to the base film after passing through the internal roller.