JP5711031B2 - Coating apparatus and coating film forming system - Google Patents

Description

  The present invention relates to a coating apparatus for forming a coating film on a base material by applying a coating liquid of an active material used as an electrode material of a chemical battery to the base material, and a coating film forming system incorporating the coating apparatus. About.

  Conventionally, a method of manufacturing a chemical battery such as a lithium ion secondary battery by applying a relatively high-viscosity electrode material on a metal foil used as a base material is known (for example, Patent Documents). 1).

  Here, in the manufacturing method of Patent Document 1, a coating film is formed on the metal foil by the following method. First, a strip-shaped metal foil is conveyed by a plurality of rollers directly below a slit nozzle that discharges an electrode material from an unwinding portion.

  Next, one end (width) of the metal foil in the width direction (direction perpendicular to the longitudinal direction) is detected by a position detection sensor arranged upstream of the slit nozzle in the conveyance direction of the metal foil (parallel to the longitudinal direction of the metal foil). The position of one end of both ends of the metal foil in the direction is detected.

  Subsequently, based on the detected position of the one end, the slit nozzle is moved along the width direction. Thereby, the electrode material can be applied at a position away from the reference position along the width direction by a certain distance with one end of the metal foil in the width direction as the reference position. And application | coating of an electrode material is performed with respect to both main surfaces (both surfaces) of metal foil, and a coating film is formed on both surfaces of metal foil.

Japanese Patent No. 4259026

  However, the size of the metal foil in the width direction is not necessarily constant, and the coating position of the coating film having one end as a reference position is different from the coating position of the coating film having the other end as a reference position. As a result, when the reference position of the coating film formed on one main surface is unknown, there arises a problem that the coating positions of the coating films formed on both main surfaces cannot be matched.

  Therefore, in the present invention, when a coating film is formed on one main surface of the base material, a coating apparatus that can satisfactorily form a coating film on the other main surface, and this coating apparatus are incorporated. An object is to provide a coating film forming system.

  In order to solve the above problems, the invention of claim 1 is directed to the second main surface of the base material in a state where the first coating film of the active material is formed on the first main surface of the belt-shaped base material. A coating apparatus for forming a second coating film on the second main surface by applying an active material coating liquid to the second main surface, wherein the first coating film is formed along a longitudinal direction of the substrate. At the same time, when the second coating film is formed, the base material is transported along the longitudinal direction, and the second of the base material from the slit-shaped discharge port along the width direction of the base material. A nozzle that discharges the coating liquid toward the main surface and a transport path of the base material along the longitudinal direction are arranged at a detection position upstream of the discharge position of the nozzle and in the width direction. Position detection for detecting the first end positions of the first coating film for each part of the base material And determining the position of the nozzle in the width direction based on the first end position detected by the position detection unit and a drive unit that moves the nozzle along the width direction. And a control unit that determines a formation position of the second coating film in each part of the material.

  According to a second aspect of the present invention, in the coating apparatus according to the first aspect, the position detection unit is a two-dimensional laser displacement meter.

  Further, the invention of claim 3 is the coating apparatus according to claim 1, wherein the position detection unit is configured to capture an image of the vicinity of both ends of the first coating film in the width direction, and the imaging unit. And an arithmetic unit that calculates the first both end positions of the first coating film along the width direction based on the obtained image.

  Further, the invention of claim 4 is the coating apparatus according to any one of claims 1 to 3, wherein the position detection unit is configured to provide the second part of the base material in the width direction for each part of the base material. Both end positions are detected together with the first both end positions.

  Moreover, invention of Claim 5 is equipped with the coating device in any one of Claims 1-4, and the drying apparatus which dries the said coating liquid on the said base material apply | coated with the said coating device. It is characterized by.

  According to the first to fifth aspects of the present invention, the position detector can detect the first end positions of the first coating film in the width direction for each part of the substrate. Thereby, even if the size of the base material in the width direction varies in each part of the base material, the formation position and width of the first coating film can be accurately detected.

  Therefore, the position of the nozzle can be determined so that the positions where the first and second coating films are formed in each part of the substrate. Further, the formation failure of the first coating film can be found based on the detected width of the first coating film.

  In particular, according to the invention described in claim 4, in each part of the base material, not only the first both end positions of the first coating film along the width direction but also the second both end positions of the base material along the width direction. Can also be detected. Therefore, not only the information regarding the first coating film but also the information regarding the feeding state of the base material (for example, the meandering state of the base material in the width direction) can be acquired.

It is a front view which shows an example of the whole structure of the coating film formation system incorporating the coating device which concerns on this invention. It is a front view which shows schematic structure of a coating process part. It is a side view for demonstrating the positional relationship of a nozzle and a position detection part. It is sectional drawing seen from the VI-VI line of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<1. Configuration of coating film forming system>
FIG. 1 is a diagram showing an overall configuration of a coating film forming system 1 incorporating a coating apparatus according to the present invention. In addition, in FIG. 1 and each subsequent figure, in order to clarify a directional relationship, the XYZ orthogonal coordinate system which makes a Z-axis direction a perpendicular direction and makes XY plane a horizontal surface is attached | subjected. Further, in FIG. 1 and the subsequent drawings, the dimensions and number of each part are exaggerated or simplified as necessary for easy understanding.

  The coating film forming system 1 manufactures an electrode of a lithium ion secondary battery by forming a coating film of an active material on a substrate 5 and drying the formed coating film. As shown in FIG. 1, the coating film forming system 1 mainly includes a coating processing unit 10, a preheating unit 60, a drying unit 65, an annealing unit 70, a cooling unit 75, and a transport unit 80. Further, the coating film forming system 1 includes an electrical box 9 that houses a power source, a control unit 90 (see FIG. 2) described later, and the like.

  Here, the base material 5 is a strip-shaped metal foil that functions as a current collector of a lithium ion secondary battery. More specifically, the shape of the substrate 5 is a long sheet. Moreover, although the width | variety and thickness of the base material 5 are not specifically limited, The width | variety of the base material 5 can be 600 mm-700 mm, and the thickness of the base material 5 can be 10 micrometers-20 micrometers. .

  Moreover, in the coating film formation system 1, when the positive electrode of a lithium ion secondary battery is manufactured, aluminum foil (Al) can be used as the base material 5, for example. On the other hand, when the negative electrode is manufactured, for example, a copper foil (Cu) can be used as the substrate 5.

  As shown in FIG. 1, the belt-shaped base material 5 is fed from the unwinding roller 81 and wound by the winding roller 82, so that the coating processing unit 10, the preheating unit 60, the drying unit 65, the annealing unit 70, It is conveyed to each part of the cooling unit 75 in this order. The conveying unit 80 includes the unwinding roller 81 and the winding roller 82 and a plurality of auxiliary rollers 83a to 83e, and conveys the base material 5 along the direction of the arrow AR1. In addition, about the number and arrangement | positioning of auxiliary roller 83a-83e, it is not limited to the example of FIG. 1, It can increase / decrease suitably as needed.

  The coating processing unit 10 forms a coating film on the substrate 5 by applying a coating solution of an active material used as an electrode material to the substrate 5. The application processing unit 10 is on the downstream side of the unwinding roller 81 in the transport path 8 along the longitudinal direction (arrow AR1 direction) of the base material 5 (hereinafter also simply referred to as “longitudinal direction”), and is a preheating unit. 60 on the upstream side. The detailed configuration of the coating processing unit 10 will be described later.

  The preheating unit 60 raises the temperature of the coating film of the electrode material formed on the substrate 5 by the coating process in the coating processing unit 10 and performs preheating for a predetermined time. The drying unit 65 is a processing unit that performs a main drying process, and blows hot air on the coating film preheated by the preheating unit 60 to heat and evaporate the solvent. Further, the annealing unit 70 heats the coating film to a higher temperature, removes the solvent remaining in the coating film, and removes strain and residual stress generated in the coating film by the drying process in the drying unit 65. . The cooling unit 75 cools the coating film by blowing dry air at normal temperature onto the heated coating film.

  As described above, the preheating unit 60, the drying unit 65, the annealing unit 70, and the cooling unit 75 can be used as a drying device that dries the coating liquid on the substrate 5 applied by the coating processing unit 10. In addition, as a drying apparatus which dries the coating film formed on the base material 5, it is not limited to the structure provided with said four process part, According to the kind of coating liquid, it is appropriate and can do. For example, the drying device may be configured only by the preheating unit 60 and the drying unit 65.

  The control unit 90 controls the operation of each element of the coating film forming system 1 and realizes various data calculations. As shown in FIG. 2, the control unit 90 mainly includes a ROM 91, a RAM 92, and a CPU 93.

  A ROM (Read Only Memory) 91 is a so-called nonvolatile storage unit, and stores, for example, a program 91a. As the ROM 91, a flash memory that is a readable / writable nonvolatile memory may be used. A RAM (Random Access Memory) 92 is a volatile storage unit and stores, for example, data used in the calculation of the CPU 93.

  A CPU (Central Processing Unit) 93 executes control according to the program 91a of the ROM 91 (for example, control of the movement operation of the nozzle 11 by the drive unit 15, the discharge operation of the coating liquid by the closing valve 20 and the pump 51, etc.). Is done.

<2. Configuration of coating processing section>
FIG. 2 is a diagram showing a schematic configuration of the coating processing unit 10 which is a coating apparatus according to the present invention. FIG. 3 is a side view for explaining the positional relationship between the nozzle 11 and the position detector 13. 4 is a cross-sectional view taken along line VI-VI in FIG. Here, the configuration of the coating processing unit 10 will be described with reference to FIGS. 2 to 4.

  As shown in FIG. 2, the coating processing unit 10 is configured such that the first main coating surface 6 a of the active material is formed on the first main surface 5 a of the strip-shaped base material 5, and the second main surface of the base material 5. An active material coating solution is applied to 5b. Thereby, the 2nd coating film 7 is formed on the 2nd main surface 5b of the base material 5. FIG. As shown in FIG. 2, the application processing unit 10 mainly includes a nozzle 11, a position detection unit 13, a drive unit 15, a tank 50, a pump 51, a supply pipe 55, and a closing valve 20. ing.

  In addition, in the belt-like sheet body extending in the longitudinal direction like the base material 5, the “main surface” means a surface parallel to each of the longitudinal direction and the width direction of the base material 5.

  The tank 50 is a supply source for supplying the electrode material for the positive electrode or the negative electrode to the base material 5. The tank 50 stores a solution of an active material that is an electrode material of a lithium ion secondary battery as a coating solution.

Here, when a positive electrode is manufactured in the coating film forming system 1, the tank 50 includes, for example, lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material and carbon ( A mixed liquid of C), polyvinylidene fluoride (PVDF) as a binder, and N-methyl-2-pyrrolidone (NMP) as a solvent is stored.

As the positive electrode active material, lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), lithium iron phosphate (LiFePO ₄ ), or the like can be used instead of lithium cobaltate, but these materials are limited. Is not to be done.

  On the other hand, when the negative electrode is manufactured in the coating film forming system 1, the tank 50 contains, for example, graphite (graphite) as a negative electrode active material, PVDF as a binder, and a solvent as a coating liquid for the negative electrode material. A liquid mixture of NMP is stored.

As the negative electrode active material, hard carbon, lithium titanate (Li ₄ Ti ₅ O ₁₂ ), a silicon alloy, a tin alloy, or the like can be used instead of graphite, but the material is not limited to these materials.

In both the positive electrode material and the negative electrode material, styrene-butadiene rubber (SBR) or the like is used as a binder instead of PVDF, and water (H ₂ O) or the like is used as a solvent instead of NMP. it can. Furthermore, when SBR is used as the binder and water is used as the solvent, carboxymethylcellulose (CMC) can be used as a thickener.

  Furthermore, the coating liquid of these positive electrode material and negative electrode material is a slurry in which solid (fine particles) are dispersed. Each of these coating solutions has a viscosity of 1 Pa · s (pascal second) or more, and generally has thixotropic properties.

  The tank 50 is provided with a stirrer 53 and an air pressurizing unit 54. The stirrer 53 has a screw 53a, and the screw 53a can be immersed in the coating liquid in the tank 50. Therefore, the coating liquid stored in the tank 50 is agitated by rotating the screw 53a.

  The air pressurization unit 54 pressurizes the liquid level of the coating liquid stored by sending high-pressure air into the gas phase portion in the tank 50. Note that the air pressurization unit 54 is not an essential element as long as the liquid can be fed only by the pump 51.

  The tank 50 and the nozzle 11 are connected in communication by a supply pipe 55. As the supply pipe 55, a stainless steel pipe or a resin pipe can be used. A pump 51, a closing valve 20, and a flow meter 52 are interposed in the course of the supply pipe 55. Further, a circulation pipe 56 is provided branching from the middle of the supply pipe 55. The proximal end side of the circulation pipe 56 is connected to a position between the closing valve 20 and the pump 51 of the supply pipe 55, and the distal end side is connected to the tank 50. A circulation valve 57 and a flow rate adjustment valve 58 are inserted in the circulation pipe 56.

  The pump 51 is provided in the supply pipe 55, and sends the electrode material coating liquid stored in the tank 50 toward the nozzle 11. The flow meter 52 measures the flow rate of the coating liquid flowing through the supply pipe 55. The closing valve 20 opens and closes the flow path of the supply pipe 55, thereby intermittently supplying the coating liquid to the nozzle 11.

  A circulation valve 57 provided in the circulation pipe 56 opens and closes the flow path of the circulation pipe 56. When the circulation valve 57 is opened while the supply valve 55 is closed by the closing valve 20, the coating liquid flowing through the supply pipe 55 flows into the circulation pipe 56 and is returned to the tank 50. The flow rate of the coating liquid flowing through the circulation pipe 56 is adjusted by a flow rate adjusting valve 58.

  As shown in FIG. 2, the nozzle 11 is disposed at a position facing the backup roller 12. At the tip of the nozzle 11, there is a slit-like shape along the width direction of the substrate 5 (the direction of the arrow AR2 in FIG. 3) (the direction orthogonal to the longitudinal direction of the substrate 5: hereinafter simply referred to as “width direction”). A discharge port 11a is provided. Then, the coating liquid supplied via the supply pipe 55 and discharged from the discharge port 11 a is discharged toward the base material 5 pressed and supported by the backup roller 12.

  The position detection unit 13 is a sensor configured by a so-called two-dimensional laser displacement meter. As shown in FIGS. 2 and 3, the position detection unit 13 is disposed at a detection position PS upstream of the discharge position PD of the nozzle 11 in the transport path 8 of the base material 5 along the longitudinal direction, and is backed up. It faces the roller 13a. As shown in FIG. 4, the position detector 13 mainly has a plurality of distance measuring units 14. In FIG. 3, the arrangement of the nozzles 11 and the position detection unit 13 is schematically illustrated, and the discharge position PD and the detection position PS are described closer than actual.

  As shown in FIG. 4, the plurality of distance measuring units 14 are arranged one-dimensionally along the arrangement direction (the direction of the arrow AR3). Each ranging unit 14 outputs an analog signal corresponding to the distance to the object. As shown in FIG. 4, each distance measuring unit 14 includes a light projecting light source 14 a and a light receiving unit 14 b.

  The light projecting light source 14a is, for example, a laser light source, and emits a laser toward an object. The light receiving unit 14b receives the laser beam emitted from the corresponding light projecting light source 14a and reflected by the object. Each light receiving unit 14b outputs an analog signal (for example, voltage) corresponding to the intensity of the received laser.

  Therefore, the position detection unit 13 compares the analog signals output from the distance measuring units 14 with the CPU 93 of the control unit 90, so that both end positions PE1 and PE2 (first end position of the first coating film 6 in the width direction). : See FIG. 3) for each part of the substrate 5.

  For example, the analog signal values of the adjacent ranging units 14 are compared in the order defined by the arrow AR3 (see FIG. 4). When the analog signal values of the adjacent ranging units 14 have the same sign and the values of both analog signals change sharply, the position PE1 (FIG. 4) is based on the positions of these adjacent ranging units 14. Reference) is required.

  And the control part 90 determines the position of the nozzle 11 in the width direction based on the both end positions PE1 and PE2 detected by the position detection part 13, and thereby the second coating film 7 in each part of the substrate 5 is determined. The formation position is determined.

  As described above, the position detection unit 13 can detect the positions PE1 and PE2 of the first coating film 6 in the width direction for each part of the base material 5. Thereby, even if the size of the base material 5 in the width direction varies in each part of the base material 5, the formation position of the first coating film 6 can be accurately detected. Therefore, the coating processing unit 10 can accurately match the formation positions of the two coating films 6 and 7 formed on the two main surfaces 5a and 5b of the base material 5. As a result, the performance of the chemical battery having both the coating films 6 and 7 can be improved.

  Further, when both end positions PE1 and PE2 are detected by the position detection unit 13, the size of the first coating film 6 in the width direction (hereinafter simply referred to as “width of the first coating film 6”) for each portion of the substrate 5 Can be obtained). Then, the measured value of the width of the first coating film 6 obtained is compared with the design value of the width of the first coating film 6, whereby a formation defect of the first coating film 6 can be found.

  Moreover, the position detection part 13 detects the both-ends position PB1 and PB2 (2nd both-ends position: refer FIG. 3) of the base material 5 in the width direction about each part of the base material 5 with above-mentioned both-ends position PE1 and PE2. be able to.

  For example, the analog signal values of the distance measuring units 14 are compared in the order defined by the arrow AR3 (see FIG. 4). Then, the position of the distance measuring unit 14 at which the value of the analog signal of the adjacent distance measuring unit 14 becomes almost zero is set as a position PB1 (see FIG. 4).

  And the control part 90 can acquire the information regarding the feeding condition (for example, the meandering condition of the base material 5 in the width direction) of the base material 5 based on the both end positions PB1 and PB2 detected by the position detection part 13. it can.

  Returning to FIG. 2, the drive unit 15 adjusts the position of the discharge port 11 a with respect to the backup roller 12 by moving the nozzle 11 back and forth, right and left, and up and down (XYZ direction in FIG. 2). That is, the drive unit 15 moves the nozzle 11 at least along the width direction.

  The pressure gauge 18 measures the pressure of the coating liquid in the nozzle 11. Further, the pressure of the coating liquid in the nozzle 11 is measured by the pressure gauge 18, and the flow rate of the coating liquid flowing through the supply pipe 55 is measured by the flow meter 52, whereby the state of the coating liquid flowing through the supply pipe 55 is changed. I can grasp.

<3. Advantages of coating processing unit and coating film forming system of the present embodiment>
As described above, the coating processing unit 10 according to the present embodiment and the coating film forming system 1 incorporating the coating processing unit 10 are arranged such that the both end positions PE1 and PE2 of the first coating film 6 in the width direction are each of the base material 5. The part can be detected. Thereby, even if the size of the base material 5 in the width direction varies in each part of the base material 5, the formation position and width of the first coating film 6 can be accurately detected.

  Therefore, the position of the nozzle 11 can be determined so that the formation positions of the first and second coating films 6 and 7 coincide in each part of the substrate 5. Further, the formation failure of the first coating film 6 can be found by the detected width of the first coating film 6.

<4. Modification>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made.

  (1) In the present embodiment, the position detection unit 13 has been described as being constituted by a so-called two-dimensional laser displacement meter, but is not limited to this. For example, what has an imaging part and a calculating part may be made into a position detection part. Moreover, the film thickness of the 1st and 2nd coating films 6 and 7 may be measured using the laser beam reflected by the coating film and the laser beam transmitted through the coating film.

  For example, in the case of a position detection unit having an imaging unit and a calculation unit, the imaging unit images the vicinity of both end positions PE1 and PE2 of the first coating film 6 in the width direction. The calculation unit calculates both end positions PE1 and PE2 of the first coating film 6 along the width direction based on the image captured by the imaging unit.

  Thereby, similarly to the position detector 13, the position detector can detect both end positions PE1 and PE2 of the first coating film 6 in the width direction and both end positions PB1 and PB2 of the base material 5 in the width direction. Note that the functions of the calculation unit described above may be realized by the CPU 93 of the control unit 90.

  (2) In the present embodiment, the control unit 90 controls the operation of each element of the coating film forming system 1 (the coating processing unit 10, the preheating unit 60, the drying unit 65, the annealing unit 70, and the cooling unit 75). In addition, although it has been described that the arithmetic processing related to each of these elements is executed, the present invention is not limited to this. For example, the control unit 90 may be dedicated to the coating processing unit 10, and the coating processing unit 10 may include the control unit 90.

DESCRIPTION OF SYMBOLS 1 Coating film formation system 5 Base material 5a 1st main surface 5b 2nd main surface 6 1st coating film 7 2nd coating film 8 Conveyance path 10 Coating processing part 11 Nozzle 11a Discharge port 13 Position detection part 15 Drive part 60 Preheating part 65 Drying section 70 Annealing section 75 Cooling section 80 Transport section 90 Control section PS detection position PD discharge position

Claims (5)

In a state where the first coating film of the active material is formed on the first main surface of the belt-shaped base material, the second material surface is coated with an active material coating liquid on the second main surface of the base material. A coating apparatus for forming a second coating film on a main surface,
The first coating film is formed along the longitudinal direction of the base material,
When the second coating film is formed, the substrate is transported along the longitudinal direction,
(a) a nozzle that discharges the coating liquid from a slit-like discharge port along the width direction of the substrate toward the second main surface of the substrate;
(b) In the transport path of the base material along the longitudinal direction, the first end position of the first coating film in the width direction is arranged at a detection position upstream of the discharge position of the nozzle. A position detector for detecting each part of the substrate;
(c) a drive unit that moves the nozzle along the width direction;
(d) determining the position of the second coating film in each part of the substrate by determining the position of the nozzle in the width direction based on the first end position detected by the position detection unit. A control unit to determine;
An applicator characterized by comprising: The coating apparatus according to claim 1,
The position detecting unit is a two-dimensional laser displacement meter. The coating apparatus according to claim 1,
The position detector is
(b-1) an imaging unit capable of imaging near both ends of the first coating film in the width direction;
(b-2) a calculation unit that calculates the first both end positions of the first coating film along the width direction based on an image captured by the imaging unit;
A coating apparatus comprising: In the coating device in any one of Claims 1-3,
The said position detection part detects the 2nd both-ends position of the said base material in the said width direction about each part of the said base material with the said 1st both-ends position. A coating apparatus according to any one of claims 1 to 4,
A drying device for drying the coating solution on the substrate coated by the coating device;
A coating film forming system comprising:

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