JP2020081933A - Gravure coating apparatus - Google Patents

Abstract

To provide a gravure coating apparatus in which a doctor blade can be continuously replaced without increasing the number of driving devices.SOLUTION: A gravure coating apparatus 30 includes: a resin doctor blade 34 which scrapes off ceramic slurry adhering on an outer peripheral surface of a gravure roll 32; a supply part 36 which is rotatably arranged on one end side of a rotation axis L of the gravure roll 32 and on which the long band-like doctor blade 34 is wound around; and a winding part 37 which is rotatably arranged on the other end side of the rotation axis L of the gravure roll 32, and rotates and winds up the doctor blade 34 supplied from the supply part 36. The gravure coating apparatus 30 includes first-third power transmission parts 39a-39c which rotate the winding part 37 by transmitting rotation of the gravure roll 32 to the winding part 37, and a pair of holding plates 38 which are arranged between the supply part 36 and the winding part 37 in a direction along the rotation axis L of the gravure roll 32 and hold the doctor blade 34.SELECTED DRAWING: Figure 3

Description

The present invention relates to a gravure coating device including a doctor blade.

BACKGROUND ART Conventionally, lithium ion secondary batteries, nickel-hydrogen secondary batteries, and the like have been known as power storage devices mounted on vehicles such as EVs (Electric Vehicles) and PHVs (Plug-in Hybrid Vehicles). The power storage device includes an electrode assembly in which positive and negative electrodes are stacked. The electrode has a current collector, an active material layer present on one or both sides of the current collector, and a protective layer present on the surface of the active material layer. The production of such an electrode is generally carried out by applying a ceramic slurry to the surface of the active material layer on a base material sheet having an active material layer on both sides of a long strip current collector (for example, a metal foil). And a drying step of drying the coated ceramic slurry to form a protective layer.

An example of a coating device that performs the coating step is a gravure coating device (see Patent Document 1). The gravure coating device includes a storage part in which the ceramic slurry is stored, a gravure roll to which the ceramic slurry stored in the storage part adheres to the outer peripheral surface, and a drive device for rotating the gravure roll. By rotating the gravure roll, the ceramic slurry is transferred to the base material sheet conveyed by the conveying device. Further, the gravure coating device includes a doctor blade made of resin for scraping off the excess ceramic slurry attached to the outer peripheral surface of the gravure roll.

By the way, when a slurry containing a hard material such as ceramic is scraped off by a doctor blade made of resin, the wear rate of the doctor blade is high. Therefore, there is a problem that the frequency of replacement of the doctor blade becomes high.

Patent Document 2 discloses a doctor device that solves such a problem. The doctor device is arranged on one end side of the rotation axis of the gravure roll, and is provided on the supply section on which the long strip doctor blade is wound, and on the other end side of the rotation axis of the gravure roll, and is supplied from the supply section. A winding unit for winding the doctor blade and a drive device for rotating the winding unit are provided. The doctor blade supplied from the supply unit is wound around the rotating winding unit to be conveyed from one end side to the other end side of the rotation axis of the gravure roll. In this case, until the supply of the doctor blade from the supply unit is completed, the portion of the doctor blade that scrapes off the excess slurry adhering to the gravure roll is continuously replaced. Therefore, the frequency of replacing the doctor blade can be reduced.

Japanese Patent Laid-Open No. 2018-122215 JP, 10-325094, A

However, when the doctor device disclosed in Patent Document 2 is added to the gravure coating device disclosed in Patent Document 1, the drive device for transporting the doctor blade causes the size of the gravure coating device to increase. Further, it is necessary to convey the doctor blade in response to the rotation of the gravure roll.

The present invention has been made to solve the above problems, and an object thereof is to provide a gravure coating apparatus capable of continuously exchanging a doctor blade without increasing the number of driving apparatuses.

A gravure coating apparatus for solving the above problems, a storage unit in which a ceramic slurry is stored, a gravure roll to which the ceramic slurry stored in the storage unit adheres to an outer peripheral surface, and the gravure roll are rotated. A driving device and a doctor blade made of resin for scraping off the excess ceramic slurry adhering to the outer peripheral surface of the gravure roll, and by the rotation of the gravure roll, carry from the upstream side to the downstream side in the carrying direction. A gravure coating apparatus in which the ceramic slurry is transferred to a substrate sheet to be rotatably arranged at one end side of the rotation axis of the gravure roll, and the long strip-shaped doctor blade is wound around the supply. Part, a rotatably arranged on the other end side of the rotation axis of the gravure roll, a winding part that winds by rotating the doctor blade supplied from the supply part, and the rotation of the gravure roll. The doctor blade is sandwiched between the power transmission mechanism that rotates the winding unit by transmitting to the winding unit and the supply unit and the winding unit in the direction along the rotation axis of the gravure roll. And a pair of sandwiching plates that are provided.

According to this, the rotation of the gravure roll is transmitted to the winding section by the power transmission mechanism, and the winding section is rotated, so that the doctor blade supplied from the supply section is wound around the winding section. Therefore, the doctor blade is conveyed from one end side to the other end side of the rotation axis of the gravure roll, and the portion of the doctor blade scraping off the excess slurry is continuously exchanged with the gravure roll. As described above, since the winding portion is rotated by using the rotational force of the gravure roll as a power source, the doctor blade can be continuously replaced without increasing the number of driving devices.

In addition, the doctor blade is sandwiched between the supply unit and the winding unit by the pair of sandwiching plates, so that the bending of the doctor blade during transportation is suppressed. Therefore, the position of the doctor blade with respect to the outer peripheral surface of the gravure roll can be stabilized. As a result, the ceramic slurry having a desired thickness can be attached to the outer peripheral surface of the gravure roll.

Further, in the gravure coating apparatus, it is preferable that balls are interposed between the sandwiching plate and the doctor blade.
According to this, the doctor blade is smoothly transported between the pair of holding plates.

According to the present invention, the doctor blade can be continuously replaced without increasing the number of drive devices.

The perspective view of an electrode. Sectional drawing of a gravure coating device. The perspective view of a gravure coating device.

An embodiment of the gravure coating device will be described below.
The gravure coating apparatus of the present embodiment is used in the process of manufacturing an electrode of a secondary battery as a power storage device (not shown). The secondary battery is, for example, a lithium ion battery including an electrode assembly and a case that houses the electrode assembly. The electrode assembly is configured by alternately stacking the positive electrode and the negative electrode while being insulated by the separator.

As shown in FIG. 1, an electrode 10 for a secondary battery includes a rectangular sheet-shaped current collector (metal foil) 11, active material layers 12 present on both surfaces of the current collector 11, and an active material layer 12. And a protective layer 13 present on the surface. The electrode 10 has a tab 14 protruding from a part of one side of the current collector 11. The tab 14 is composed of the current collector 11 itself. The protective layer 13 includes alumina particles as ceramic particles and a binder made of resin, and has a layer structure in which alumina particles are bonded to each other or the alumina particles and the active material particles on the surface of the active material layer 12 are bonded via the binder. ..

Next, the manufacturing process of the electrode 10 will be described.
The manufacturing process of the electrode 10 includes an active material layer forming process, a protective layer forming process, and a cutting process.
The active material layer forming step is a step of manufacturing the base material sheet 15 in which the active material layers 12 are formed on both surfaces of the metal foil material 11a shown in FIG. The active material layer forming step is performed while conveying the metal foil material 11a in the longitudinal direction. In the active material layer forming step, first, an active material paste is applied to the metal foil material 11a. Next, the coated active material paste is dried to form an active material layer precursor. Next, the active material layer precursor is roll-pressed to increase the active material density. Thereby, the active material layers 12 having a predetermined active material density and thickness are formed on both surfaces of the metal foil material 11a. It should be noted that the active material layer 12 is not formed over the entire longitudinal direction of the base material sheet 15 on one end side in the lateral direction of the base material sheet 15, and an uncoated portion where the metal foil material 11a is exposed is formed. It

In the protective layer forming step, the protective layer 13 is formed on the surface of the active material layer 12 of the base material sheet 15. The protective layer forming step is performed while the base material sheet 15 is transported in the longitudinal direction by a transport device (not shown). The direction along the longitudinal direction of the base sheet 15, the direction in which the base sheet 15 is conveyed is the conveying direction, the direction along the lateral direction of the base sheet 15, and the direction orthogonal to the conveying direction is the width direction. And Further, the direction orthogonal to both the transport direction and the width direction is the vertical direction.

In the protective layer forming step, the ceramic slurry S is applied to the surface of the active material layer 12 on one surface of the base material sheet 15 conveyed from the upstream side to the downstream side in the conveying direction by the gravure coating device 30. Work. Next, the applied ceramic slurry S is dried by the drying device 40 arranged on the downstream side of the gravure coating device 30 in the transport direction. As a result, the protective layer 13 is formed on one surface of the base material sheet 15. Although not shown, the other surface of the base material sheet 15 is similarly coated with the ceramic slurry S on the surface of the active material layer 12, and the coated ceramic slurry S is dried to form the protective layer 13. As a result, a strip-shaped electrode material in which the protective layers 13 are formed on the surfaces of the active material layers 12 on both surfaces of the base material sheet 15 is manufactured.

Although not shown, in the cutting step, the electrode material is cut into the shape of the electrode 10 shown in FIG. Thus, the rectangular sheet-shaped current collector (metal foil) 11 is formed from the metal foil material 11a, and the tab 14 is formed from the uncoated portion. As a result, the electrode 10 having the current collector 11, the active material layer 12 present on both surfaces of the current collector 11, and the protective layer 13 present on the surface of the active material layer 12 is manufactured.

Next, the gravure coating device 30 will be described in detail.
As shown in FIGS. 2 and 3, the gravure coating device 30 includes a storage portion 31 in which the ceramic slurry S is stored, and a gravure roll 32 that transfers the ceramic slurry S in the storage portion 31 to the base sheet 15. And a motor 33 as a drive device for rotating the gravure roll 32. In addition, in FIG. 3, the illustration of the storage unit 31 is omitted.

As shown in FIG. 2, the storage unit 31 is arranged below the base material sheet 15 between the pair of backup rollers 21 in the transport direction. The storage part 31 opens toward the base material sheet 15.

The gravure roll 32 is arranged between the base sheet 15 and the storage section 31 in the vertical direction. The gravure roll 32 has a roll rotation shaft 32a and a cylindrical roll body 32b into which the roll rotation shaft 32a is inserted and which can rotate integrally with the roll rotation shaft 32a. The gravure roll 32 is arranged so that the roll rotation shaft 32a extends along the width direction. A motor 33 is connected to one end of the roll rotation shaft 32a, and the motor 33 rotates the roll rotation shaft 32a and the roll body 32b. The gravure roll 32 rotates in a direction in which the upper portion of the roll body 32b moves from the upstream side to the downstream side in the transport direction. The rotation axis L of the gravure roll 32 extends in the width direction.

The roll main body 32b is supported by the roll rotation shaft 32a in a state where a part in the circumferential direction is always immersed in the ceramic slurry S in the storage section 31. The roll body 32b is made of hard rubber (for example, nitrile rubber). The roll body 32b has a diagonal gravure pattern on the outer peripheral surface. The gravure pattern is composed of a plurality of grooves 321 engraved linearly on the outer peripheral surface of the roll body 32b. The plurality of grooves 321 are present at equal intervals along the circumferential direction of the roll body 32b. Each groove 321 is present in the entire direction along the rotation axis L of the gravure roll 32, that is, from the outer peripheral surface on one end side of the roll body 32b to the outer peripheral surface on the other end side of the roll body 32b. The position of one end of each groove 321 and the position of the other end of each groove 321 are displaced in the circumferential direction of the roll body 32b. That is, each groove 321 is inclined with respect to the rotation axis L of the gravure roll 32.

The gravure coating device 30 includes a long strip doctor blade 34 that scrapes off the excess ceramic slurry S attached to the outer peripheral surface of the roll body 32b of the gravure roll 32. The doctor blade 34 of this embodiment is made of reinforced polyester. The doctor blade 34 has a blade 34a at one end in the lateral direction. The blade 34a exists over the entire length of the doctor blade 34 in the longitudinal direction.

As shown in FIG. 3, the gravure coating device 30 includes a transport device 35 that transports the doctor blade 34. The transport device 35 is arranged upstream of the gravure roll 32 in the transport direction and on both sides of the gravure roll 32 in the width direction. The transport device 35 includes a supply unit 36 that supplies the doctor blade 34 having a long strip shape, and a winding unit 37 that winds the doctor blade 34 supplied from the supply unit 36. The supply unit 36 is rotatably arranged on one end side in the width direction, and the winding unit 37 is rotatably arranged on the other end side in the width direction. That is, the supply unit 36 is arranged on one end side of the rotation axis L of the gravure roll 32, and the winding unit 37 is arranged on the other end side of the rotation axis L of the gravure roll 32.

The supply unit 36 includes a supply-side rotation shaft 36a and a supply reel 36b through which the supply-side rotation shaft 36a is inserted and which is rotatable integrally with the supply-side rotation shaft 36a. The doctor blade 34 is wound around the supply reel 36b. The supply unit 36 is arranged such that the supply-side rotation shaft 36a extends in the transport direction. The supply-side rotation shaft 36a is inclined such that one end located on the downstream side in the carrying direction is located below the other end located on the upstream side in the carrying direction.

The winding unit 37 includes a winding side rotation shaft 37a and a winding reel 37b into which the winding side rotation shaft 37a is inserted and which is rotatable integrally with the winding side rotation shaft 37a. The doctor blade 34 supplied from the supply unit 36 can be wound around the take-up reel 37b. The winding unit 37 is arranged such that the winding-side rotation shaft 37a extends along the transport direction. The winding side rotation shaft 37a is inclined such that one end located on the downstream side in the carrying direction is located below the other end located on the upstream side in the carrying direction.

One end of the doctor blade 34 wound around the supply reel 36b in the longitudinal direction is connected to the take-up reel 37b. Therefore, the doctor blade 34 is bridged from the supply reel 36b toward the take-up reel 37b along the rotation axis L of the gravure roll 32. The blade 34a located at one end in the short side direction of the doctor blade 34 is arranged on the downstream side in the transport direction with respect to the other end in the short side direction and faces the outer peripheral surface of the roll body 32b of the gravure roll 32. Further, the doctor blade 34 is inclined such that the blade 34a located on the downstream side in the carrying direction is located below the other end in the lateral direction located on the upstream side in the carrying direction in the vertical direction. The distance between the blade 34a of the doctor blade 34 and the outer peripheral surface of the roll body 32b of the gravure roll 32 is set according to the thickness of the ceramic slurry S attached to the outer peripheral surface of the roll body 32b.

As shown in FIG. 2, the gravure coating device 30 includes a pair of holding plates 38 that hold the doctor blade 34 so that the doctor blade 34 can be conveyed. The pair of holding plates 38 of the present embodiment is made of SUS. The pair of holding plates 38 are fixed to each other by a fixing member 38a (for example, a bolt and a nut) in a state in which a space for holding the doctor blade 34 is provided. The pair of holding plates 38 are arranged between the supply unit 36 and the winding unit 37 in the direction along the rotation axis L of the gravure roll 32. Further, the pair of sandwiching plates 38 are inclined so that one edge located on the downstream side in the transport direction is located below the other edge located on the upstream side in the transport direction, similarly to the doctor blade 34. The pair of sandwiching plates 38 sandwich the portion of the doctor blade 34 that is bridged between the supply unit 36 and the winding unit 37.

A plurality of balls 38b are rotatably attached to the inner surface of each holding plate 38. Therefore, a plurality of balls 38b are interposed between the inner surface of one holding plate 38 and one end surface of the doctor blade 34, and between the inner surface of the other holding plate 38 and the other end surface of the doctor blade 34.

As shown in FIG. 3, the gravure coating device 30 includes first to third power transmission units 39 a to 39 c as a power transmission mechanism for transmitting the rotation of the gravure roll 32 to the winding unit 37 of the transport device 35. Prepare The first power transmission unit 39a is attached to the other end of the roll rotation shaft 32a. The 1st power transmission part 39a of this embodiment is a crown gear (crown gear). The second power transmission unit 39b meshes with the first power transmission unit 39a. The 2nd power transmission part 39b of this embodiment is a spur gear. The third power transmission portion 39c is attached to an end portion located on the downstream side in the transport direction, of both end portions of the winding side rotation shaft 37a. The third power transmission unit 39c meshes with the second power transmission unit 39b. The third power transmission unit 39c is a spur gear.

The operation of this embodiment will be described together with the operation of the gravure coating device 30.
When the roll rotation shaft 32a is rotated by the motor 33, the roll body 32b also rotates. By the rotation of the gravure roll 32, the ceramic slurry S in the storage portion 31 adheres to the outer peripheral surface of the roll body 32b and enters the groove 321, and is conveyed from the storage portion 31 toward the base material sheet 15. The blade 34a of the doctor blade 34 scrapes off the excess ceramic slurry S attached to the outer peripheral surface of the roll body 32b while the ceramic slurry S is conveyed from the storage portion 31 toward the base material sheet 15. The ceramic slurry S scraped off from the outer peripheral surface of the roll body 32b falls into the storage section 31.

The doctor blade 34 of the present embodiment has a long strip shape and is transported by the transport device 35 from one end side to the other end side of the rotation axis L of the gravure roll 32. The transport device 35 transports the doctor blade 34 by using the rotational force of the gravure roll 32 transmitted by the first to third power transmission units 39a to 39c as a power source.

Specifically, when the gravure roll 32 rotates, the first power transmission unit 39a attached to the end of the roll rotation shaft 32a transmits the rotation of the gravure roll 32 to the second power transmission unit 39b. At this time, the direction in which the rotation axis extends extends from the direction along the rotation axis L of the gravure roll 32 to the direction along the supply-side rotation axis 36a of the supply unit 36. Next, the second power transmission unit 39b transmits the power (rotational force) transmitted from the first power transmission unit 39a to the third power transmission unit 39c. Then, by the power (rotational force) transmitted to the third power transmission unit 39c, the winding side rotation shaft 37a to which the third power transmission unit 39c is attached rotates, and the winding reel 37b also rotates.

When the take-up reel 37b rotates, the doctor blade 34 is sequentially wound on the take-up reel 37b from one end in the longitudinal direction connected to the take-up reel 37b, and a new doctor blade 34 is fed from the supply reel 36b. In this way, the transport device 35 interlocks with the rotation of the gravure roll 32 and moves from the one end side (the supply unit 36 side) of the rotation axis L of the gravure roll 32 to the other end side (the winding unit 37 side) of the doctor blade. 34 is conveyed. As a result, the portion of the blade 34a of the doctor blade 34 that scrapes off the excess ceramic slurry S adhering to the roll body 32b moves from one end side of the rotation axis L of the gravure roll 32 to the other end side. That is, the blade 34a of the doctor blade 34 is continuously replaced with respect to the gravure roll 32. Further, since the doctor blade 34 being conveyed is clamped by the pair of clamping plates 38, bending of the doctor blade 34 between the supply unit 36 and the winding unit 37 is suppressed.

The transportation of the doctor blade 34 ends when all the doctor blades 34 wound around the supply reel 36b are fed out. In this case, the doctor blade 34 is replaced. Specifically, the empty supply reel 36b is removed from the supply side rotation shaft 36a, and the take-up reel 37b around which the doctor blade 34 is wound is removed from the take-up rotation shaft 37a. After that, a new supply reel 36b around which the doctor blade 34 is wound is attached to the supply-side rotating shaft 36a, and an empty take-up reel 37b is attached to the winding-side rotating shaft 37a, so that one end of the doctor blade 34 in the longitudinal direction is attached. It is connected to the empty take-up reel 37b.

The effects of this embodiment will be described.
(1) The 1st-3rd power transmission parts 39a-39c transmit the rotation of the gravure roll 32 to the winding part 37 of the conveying apparatus 35, and rotate the winding part 37. As the winding section 37 rotates, the doctor blade 34 supplied from the supply reel 36b of the supply section 36 is wound around the winding reel 37b of the winding section 37. Therefore, the doctor blade 34 is conveyed from one end side to the other end side of the rotation axis L of the gravure roll 32, and a portion of the blade 34 a of the doctor blade 34 that scrapes off the ceramic slurry S with respect to the gravure roll 32. Replaced continuously. Since the winding unit 37 is rotated by using the rotational force of the gravure roll 32 as a power source in this way, the doctor blade 34 can be continuously replaced without increasing the number of driving devices.

Further, the gravure coating device 30 includes a pair of holding plates 38 that hold the doctor blade 34. The pair of holding plates 38 are arranged between the supply unit 36 and the winding unit 37 in the direction along the rotation axis L of the gravure roll 32. By sandwiching the doctor blade 34 by the pair of sandwiching plates 38 between the supply unit 36 and the winding unit 37, the bending of the doctor blade 34 during conveyance is suppressed. Therefore, the position of the doctor blade 34 with respect to the outer peripheral surface of the roll body 32b of the gravure roll 32 can be stabilized. As a result, the ceramic slurry S having a desired thickness can be attached to the outer peripheral surface of the roll body 32b.

(2) A ball 38b is interposed between the inner surface of each holding plate 38 and the doctor blade 34. Therefore, the doctor blade 34 is smoothly transported between the pair of holding plates 38.

This embodiment can be modified and implemented as follows. The present embodiment and the modified examples can be implemented in combination with each other within a technically consistent range.
The doctor blade 34 is not limited to reinforced polyester. The doctor blade 34 may be made of another resin as long as it does not damage the roll body 32b when the doctor blade 34 contacts the roll body 32b of the gravure roll 32.

When the slidability between the inner surface of the holding plate 38 and the end surface of the doctor blade 34 is good, the plurality of balls 38b may not be provided on the inner surface of each holding plate 38.
Further, for example, by interposing a sliding plate having good slidability with the doctor blade 34 between the inner surface of the sandwiching plate 38 and the end surface of the doctor blade 34, the doctor blade 34 between the pair of sandwiching plates 38 can be formed. May be carried out smoothly.

Further, for example, by coating the inner surface of the sandwiching plate 38 to improve the slidability between the inner surface of the sandwiching plate 38 and the end surface of the doctor blade 34, the doctor blade 34 between the pair of sandwiching plates 38 is coated. May be carried out smoothly.

The transport speed of the doctor blade 34 may be adjusted by changing the number of teeth of the second power transmission section 39b and the third power transmission section 39c.
The configuration of the power transmission mechanism may be appropriately changed as long as the rotation of the gravure roll 32 can be transmitted to the winding section 37 of the transport device 35 and the winding section 37 can be rotated.

For example, the number of power transmission units or the type of gear (gear) may be changed. Further, for example, the power transmission unit is not limited to a gear (gear) and may be configured by a pulley and a chain.

15... Substrate sheet, 30... Gravure coating device, 31... Storage part, 32... Gravure roll, 33... Motor as drive device, 34... Doctor blade, 36... Supply part, 37... Winding part, 38... Nip Plates, 38b... Balls, 39a to 39c... First to third power transmission parts as a power transmission mechanism, S... Ceramic slurry, L... Rotation axis.

Claims (2)

A storage part in which the ceramic slurry is stored,
A gravure roll in which the ceramic slurry stored in the storage section adheres to the outer peripheral surface,
A drive device for rotating the gravure roll,
A doctor blade made of resin for scraping off the excess ceramic slurry attached to the outer peripheral surface of the gravure roll,
Equipped with
By the rotation of the gravure roll, a gravure coating apparatus in which the ceramic slurry is transferred to a base material sheet that is conveyed from the upstream side to the downstream side in the conveyance direction
A rotatably arranged one end side of the rotation axis of the gravure roll, a supply unit around which the long strip-shaped doctor blade is wound,
A winding unit that is rotatably disposed on the other end side of the rotation axis of the gravure roll and that winds by rotating the doctor blade supplied from the supply unit,
By transmitting the rotation of the gravure roll to the winding unit, a power transmission mechanism for rotating the winding unit,
A pair of clamping plates that are disposed between the supply unit and the winding unit in a direction along the rotation axis of the gravure roll, and that clamp the doctor blade,
A gravure coating apparatus comprising: The gravure coating device according to claim 1, wherein balls are interposed between the holding plate and the doctor blade.