JP6979632B2 - Coating method and coating equipment - Google Patents

Description

The present invention relates to a method and an apparatus for manufacturing a battery electrode plate used for a lithium ion secondary battery or the like.

The battery electrode plate forms a coating film of uniform thickness by discharging the coating liquid from the tip of the slit die onto the strip-shaped base material running from the supply roll to the take-up roll, and dries them. It is manufactured by. The coating liquid contains an active material, a binder, a thickener, and a solvent. Further, these electrode plates are roughly classified into a positive electrode plate and a negative electrode plate, and each electrode plate is sandwiched between separators, wound or laminated, and sealed in a can together with an electrolytic solution to form a battery. Is configured.

In particular, with the increasing spread as in-vehicle batteries in recent years, increasing capacity and safety have become issues, and it is important how to manufacture a electrode plate having a uniform thickness and a high-density coating film. ing. In order to increase the capacity of the battery, it is necessary to increase the amount of active material while reducing the amount of the base material used, and for that purpose, it is necessary to form coating films on both sides of the base material. In addition, as price reduction progresses, how to improve productivity is an issue, and various technologies are being developed.

For example, a coating film is formed on the upper surface while supporting the base material with a backup roll, dried in a drying oven, and then the base material surface is inverted and the coating film is also supported on the opposite surface with the backup roll. The method of forming the above has been conventionally proposed.

Although the coating film can be stably produced by this method, the equipment cost increases because two drying processes are required and the surface needs to be turned over when forming the coating film on the lower surface. There were problems such as lengthening and the need for space, and there was a problem of low productivity.

Patent Document 1 is a method for solving the above problems.

Patent No. 4354598 WO2011 / 001648A1

For example, as in Patent Document 1, the discharge ports of the first and second slit dies are opposed to each other with the base material sandwiched between them, and the coating liquid is simultaneously discharged from the first and second slit dies while the base material is discharged. In the method of forming the coating film on both sides of the substrate and drying it at the same time to form the electrode plates on both sides of the substrate at once, if the discharge pressure is different for each slit die, the position of the substrate will be affected and displaced. There is a problem that it is easy to make a difference in the coating thickness of the coating liquid on the upper surface and the lower surface.

Further, as another form, for example, as in Patent Document 2, a coating film is formed on the lower surface by a slit die while supporting the base material by a backup roll, and the base material is horizontally conveyed and run to run the base material. A method has been proposed in which a die having a discharge port vertically above the vertical lower surface is installed, and a coating film is formed on the lower surface of the base material to collectively form electrode plates on both sides of the base material.

However, although this method is suitable for continuously forming a coating film, in the case of intermittently forming a coating film, the base material is bent due to the weight of the base material and the coating film, and the coating film is intermittently formed. Since the base material is easily pulled in by the surface tension when the coating liquid is pulled into the slit die, the distance between the slit die and the base material, that is, the coating gap is not stable at the center in the width direction of the base material. As shown in FIG. 7, an attempt was made to form an uncoated portion C to which the coating liquid should not be applied between the coating portion B to which the coating liquid was applied to the base material 4 and the coating portion B. In this case, the coating liquid supply to the uncoated portion C, which should not be coated with the coating liquid, is gradually stopped while bringing the coating liquid at the end of the preceding coating portion B to the uncoated portion C, whereby the coating liquid supply of the coating portion B is stopped. There is a problem that the tailing 5 is generated at the end and the shape of the end 10 of the coated portion is deteriorated. FIG. 8 shows a good example of the shape of the end 10 of the coated portion.

In view of the above problems, the present invention is good in that there is no tailing even if the base material is bent while the coating liquid is intermittently and uniformly applied to the base material using a slit die. The purpose is to form a battery electrode.

The coating method of the present invention is a coating method for intermittently forming a coating film on a base material, and is arranged so as to face the lower surface of the base material with respect to the horizontally running base material. the upstream side slit die of the slit die, to form a coating film on the lower surface of the substrate by discharging a coating liquid upward from the discharge port between the downstream slit die of the slit die, the slit The downstream side slit die is moved downward without changing the distance between the upstream side slit die of the die and the lower surface of the base material, and then the slit die is moved upward to move the upstream side slit die. It is characterized in that the coating film is brought into contact with the lower surface of the base material, and then the supply of the coating liquid to the slit die is stopped to dry the coating film.

Further, it is a coating method for intermittently forming a coating film on a base material, and is an upstream slit of a slit die arranged so as to face the lower surface of the base material with respect to the base material running horizontally. A coating film is formed on the lower surface of the base material by discharging the coating liquid upward from the discharge port between the die and the slit die on the downstream side of the slit die, and the downstream slit die descends. The entire slit die begins to rise before the downstream slit die finishes descending, and the upstream slit die is brought into contact with the lower surface of the substrate, followed by the said to the slit die. It is characterized in that the supply of the coating liquid is stopped and the coating film is dried.

Further, it is a coating method for intermittently forming a coating film on a base material, and is an upstream slit of a slit die arranged so as to face the lower surface of the base material with respect to the base material running horizontally. A coating film is formed on the lower surface of the base material by discharging the coating liquid upward from the discharge port between the die and the slit die on the downstream side of the slit die, and the slit die is moved upward. The upstream slit die is brought into contact with the lower surface of the base material, then the downstream slit die is moved downward, and the upstream slit die is brought into contact with the lower surface of the base material to the slit die. It is characterized in that the supply of the coating liquid is stopped and the coating film is dried.

Further, it is a coating method for intermittently forming a coating film on a base material, and is an upstream slit of a slit die arranged so as to face the lower surface of the base material with respect to the horizontally running base material. die and to form a coating film on the lower surface of the substrate by discharging a coating liquid upward from the discharge port between the downstream slit die of the slit die, to initiate an increase in the slit die , the upstream slit die to start lowering of the downstream slit die before contact with the said substrate,
It is characterized in that the supply of the coating liquid to the slit die is stopped in a state where the upstream slit die is in contact with the lower surface of the base material, and the coating film is dried.

Further, in the state where the upstream slit die is in contact with the lower surface of the base material, it is preferable that the upstream slit die is in contact with the lower surface of the base material in all the width directions of the base material.

The coating device of the present invention is a coating device that intermittently forms a coating film on a substrate traveling from good to bad, and is a discharge port between an upstream slit die and a downstream slit die. The slit die that supplies the coating liquid to the lower surface of the base material from the substrate, and the slit die on the upstream side of the slit die before the supply of the coating liquid to the slit die is stopped. the lower surface of the contacting on the lower surface have a control unit for instructing the movement to said slit die so as to support it, the control unit, of the substrate the upstream slit die by moving the slit die upward After that, the downstream side slit die is moved downward, and the supply of the coating liquid to the slit die is stopped in a state where the upstream side slit die is in contact with the lower surface of the base material. It is characterized by.

Further, it is a coating device that intermittently forms a coating film on a base material running from good to bad, and is below the base material from a discharge port between an upstream side slit die and a downstream side slit die. Before stopping the supply of the coating liquid to the slit die and the slit die that supplies the coating liquid to the surface of the surface, the upstream side slit die of the slit die is brought into contact with the lower surface of the base material. The control unit has a control unit for instructing the slit die to move so as to support the slit die, and the control unit starts the lowering of the downstream side slit die and before the downstream side slit die finishes the lowering. It is characterized in that the ascending of the entire surface is started, and the upstream slit die is brought into contact with the lower surface of the base material, and then the supply of the coating liquid to the slit die is stopped .

Further, it is a coating device that intermittently forms a coating film on a base material running from good to bad, and is below the base material from a discharge port between an upstream side slit die and a downstream side slit die. Before stopping the supply of the coating liquid to the slit die and the slit die that supplies the coating liquid to the surface of the surface, the upstream side slit die of the slit die is brought into contact with the lower surface of the base material. The control unit has a control unit for instructing the slit die to move so as to support the slit die, and the control unit starts the ascending of the slit die, and the downstream side before the upstream side slit die abuts on the base material. The feature is that the lowering of the slit die is started, and the supply of the coating liquid to the slit die is stopped in a state where the upstream slit die is in contact with the lower surface of the base material.

According to the coating method and coating apparatus of the present invention, by bringing the slit die into contact with the base material, the coating gap, which is the gap between the slit die and the base material, is forcibly made constant in the width direction. , It is possible to manufacture a good battery electrode plate without tailing at the end at the time of intermittent operation.

With such a configuration, the productivity of the coating film forming process can be increased, so that the capacity of the battery can be increased at low cost. Further, when the coating film is formed on both surfaces, the weight of the base material including the coating film is heavier, so that the deflection of the base material in the traveling direction is also larger. Therefore, by bringing the slit die into contact with the base material, the coating gap, which is the gap between the slit die and the base material, is forcibly made constant in the width direction, thereby improving the tailing of the end at the time of intermittent operation. ..

Configuration diagram of a coating device that executes the coating method of the present invention An explanatory diagram during (a) coating at both ends of the base material of the coating method according to the first embodiment of the present invention, and (b) an explanatory diagram of a state in which the slit die 2L on the downstream side of the slit die is subsequently lowered. After that, an explanatory diagram of a state in which the slit die is raised to bring the upstream slit die 2U into contact with the lower surface of the base material 4, and (d) the base material discharges the slit die when the supply of the coating liquid is stopped. An explanatory diagram of how the substrate is pulled into the outlet and displaced, (e) an explanatory diagram of how the liquid is running out in the process of returning the base material vertically upward, and (f) an explanatory diagram of how the intermittent operation is completed. Explanatory drawing of upstream gap H1 An explanatory view of (a) during coating in the center of the base material, (b) an explanatory view of a state in which the downstream side slit die 2L of the slit die is lowered after that, and then the slit die is raised to raise the upstream side slit. An explanatory diagram of a state in which the die 2U is in contact with the lower surface of the base material 4, and an explanatory diagram of (d) a state in which the base material is drawn into the slit die discharge port and displaced when the supply of the coating liquid is stopped. , (E) An explanatory diagram showing that the liquid is running out in the process of returning the base material vertically upward, and (f) an explanatory diagram showing how the intermittent operation is completed. An explanatory diagram during (a) coating at both ends of the base material of the coating method according to the second embodiment of the present invention, and (b) an explanatory diagram of a state in which the slit die 2L on the downstream side of the slit die is subsequently lowered. After that, an explanatory diagram of a state in which the slit die is raised to bring the upstream slit die 2U into contact with the lower surface of the base material 4, and (d) the base material discharges the slit die when the supply of the coating liquid is stopped. An explanatory diagram of how the substrate is pulled into the outlet and displaced, (e) an explanatory diagram of how the liquid is running out in the process of returning the base material vertically upward, and (f) an explanatory diagram of how the intermittent operation is completed. An explanatory view of (a) during coating in the center of the base material, (b) an explanatory view of a state in which the downstream side slit die 2L of the slit die is lowered after that, and then the slit die is raised to raise the upstream side slit. An explanatory diagram of a state in which the die 2U is in contact with the lower surface of the base material 4, and an explanatory diagram of (d) a state in which the base material is drawn into the slit die discharge port and displaced when the supply of the coating liquid is stopped. , (E) An explanatory diagram showing that the liquid is running out in the process of returning the base material vertically upward, and (f) an explanatory diagram showing how the intermittent operation is completed. Top view showing an example of bad coating with tailing Plan view showing good coating examples (A) block diagram, (b) arrow view of AA, and (c) sectional view of BB showing the state of the coating device before the start of coating. (A) A block diagram showing the state of the coating device during coating, (b) an arrow view of AA, (c) a sectional view taken along the line BB, and (d) supporting both edges of the base material. Detailed view of the cross-sectional shape of the lower surface coating film in the coating width direction after coating in the prior art gripped by the mechanism. (A) An explanatory diagram during coating at both ends of the substrate of the conventional coating method, and (b) an explanatory diagram of how the substrate is pulled into the slit die discharge port and displaced when coating is stopped. c) An explanatory diagram showing how the base material ran out in the process of returning vertically upward after that, and (d) an explanatory diagram showing how the intermittent operation was completed. (A) An explanatory diagram during coating in the center of the base material of the conventional coating method, and (b) an explanatory diagram of how the base material is pulled into the slit die discharge port and displaced when coating is stopped. c) An explanatory diagram of how the base material ran out in the process of returning vertically upward after that, (d) an explanatory diagram of how the intermittent operation was completed, and (e) an explanatory diagram of how tailing occurred.

Each embodiment of the present invention will be described with reference to the drawings.

Prior to the description of each embodiment, the principle that the terminal shape of the coated portion is deteriorated in the conventional coating method will be described.

As shown in FIG. 9A, the coating device 4 is drawn out from the winding body 40 and transferred via the backup roll 7 and the base material support device 3, and the base material 4 is the base material support device 3. The double-sided coating base material completed by passing through the drying device 6 provided in the subsequent stage is wound on the take-up reel 41. At the position of the backup roll 7, a first die head 1 for applying a coating liquid to the upper surface of the base material 4 is provided. At a position between the backup roll 7 and the base material support device 3, a second die head 2 for applying a coating liquid to the lower surface of the base material 4 is provided. X indicates a coating gap which is a gap between the second die head 2 and the base material 4.

FIG. 9B shows an arrow view of AA at the position of the base material support device 3. Reference numerals 3a and 3b are pressing rollers constituting the base material support device 3, and support both edges of the base material 4. A is a top surface coated portion coated by the first die head 1, and B is a bottom surface coated portion coated by the second die head 2.

FIG. 9C shows a sectional view taken along line BB at the position of the second die head 2.

As shown in FIG. 9B, in the state before coating, the flow of the base material 4 is adjusted by adjusting the tension in the flow direction while grasping both edges of the base material 4 with the base material support device 3. There is no bending of the base material 4 in both the direction and the width direction. As shown in FIG. 9C, the coating gap X, which is the gap between the slit die 2 and the base material 4, which affects the accuracy of the coating film weight in the width direction, is constant in the coating width direction.

FIG. 10A shows a state during continuous intermittent coating. FIG. 10B shows an arrow view of AA at the position of the base material support device 3. FIG. 10C shows a sectional view taken along line BB at the position of the second die head 2. FIG. 10D shows a detailed view of the cross-sectional shape of the lower surface coating film in the coating width direction after coating.

However, when the coating is continued, both edges of the substrate 4 are subjected to the substrate support device 3 against the increase in the weight of the substrate 4 due to the coating liquid coated as shown in FIGS. 10 (a) and 10 (b). By simply adjusting the tension in the flow direction while gripping, it becomes difficult to run the base material 4 while maintaining the same height as before coating, and it becomes difficult to run the base material 4 in both the longitudinal direction and the width direction of the base material 4. Deflection of the base material 4 occurs.

As a result, as shown in FIG. 10 (c), the coating gap X, which is the gap between the slit die 2 and the base material 4, which affects the coating film weight accuracy in the width direction, becomes narrow and non-uniform in the coating width direction. Therefore, as shown in FIG. 10D, there is a problem that the thickness of the central portion in the coating width direction becomes thinner than that in the vicinity of both end portions, and the weight accuracy of the coating film in the width direction deteriorates.

That is, if the coating is continued, the coating gap changes between both ends and the center of the base material 4. The difference in the state of the discharge port of the slit die 2 at both ends and the center of the base material 4 in the width direction will be described.

The state of both ends of the base material 4 is shown in FIG. 11, and the state of the central part of the base material 4 is shown in FIG.

At both ends of the base material 4, as shown in FIG. 11A, the coating liquid is supplied from the state in which the coating liquid is supplied to the slit die 2 installed vertically below the base material 4 for coating. When is stopped, as shown in FIG. 11B, the surface tension of the coating liquid exerts a force on the base material 4 in the direction of being drawn into the discharge port side of the slit die 2, so that the base material 4 is vertically downward. Displace to. Then, as shown in FIG. 11 (c), since the coating gap is secured at both ends of the base material 4, the coating liquid runs out, and as shown in FIG. 11 (d), coating is performed with the passage of time. The liquid returns to the inside of the slit die 2.

However, in the central portion of the base material 4, as shown in FIG. 12A, the coating gap is narrowed due to the influence of the bending of the base material 4. Then, when the supply of the coating liquid is stopped, as shown in FIG. 12B, a force acts on the base material 4 in the direction of being drawn into the discharge port side of the slit die 2 due to the surface tension of the coating liquid. , The base material 4 is displaced vertically downward, the coating gap is further narrowed, and a liquid pool 8 is formed on the upper part of the upstream slit die. Therefore, as shown in FIG. 12 (c), the liquid pool 8 is difficult to separate from the base material 4, and as shown in FIG. 12 (d), the coating is applied in a state where tailing occurs. Therefore, in the state of being coated on the base material 4, a tail trail 5 is generated at the end of the central portion of the base material, as shown in FIG. 12 (e).

(Embodiment 1)
1 to 4 show a coating apparatus for executing the coating method of the present invention.

In this coating device, a coating liquid is applied to both surfaces of a base material 4 which is a core body of an electrode such as a secondary battery or a fuel cell. From the upstream side to the downstream side in the transport direction 9, it has a backup roll 7, a slit die 1 for top coating, a slit die 2 for bottom coating, a base material support device 3, and a drying device 6. The slit die 2 is arranged at an angle θ toward the transport direction 9.

The backup roll 7 and the slit die 1 for bottom coating face each other in the horizontal direction. The base material 4 is moved from below to the facing portion between the backup roll 7 and the slit die 1 for bottom coating, is further turned by the backup roll 7, and is subsequently moved horizontally at a constant speed. The slit die 1 is a device for applying a coating liquid containing an active material to the upper surface of the base material 4. The slit die 2 is a device for applying a coating liquid containing an active material to the lower surface of the base material 4.

The drying device 6 is a device for drying the base material 4 coated with the coating liquid. In the drying apparatus 6, gas injection nozzles 60 for ejecting a gas for drying the coated surface are provided at the top and bottom, and the double-sided coated base material is conveyed in a floating state by the ejected gas. To.

FIG. 2 shows the operation of the slit die 2 at both ends of the base material 4 in the width direction. FIG. 4 shows the operation of the slit die 2 in the central portion of the base material 4 in the width direction.

As shown in FIG. 2A, the slit die 2 has an upstream side slit die 2U and a downstream side slit die 2L. A discharge port of the slit die 2 facing the lower surface of the base material 4 is formed between the tip of the upstream slit die 2U and the tip of the downstream slit die 2L. The upstream gap H1 and the downstream gap H2 of the slit die 2 vary depending on the characteristics of the coating liquid used, but are generally provided to be about 0.01 mm or more and 1.0 mm or less.

Reference numeral 11 is a control unit, which sets the vertical position of the upstream slit die 2U with respect to the lower surface of the base material 4 and the vertical position of the downstream slit die 2L with respect to the lower surface of the base material 4, and sets the upstream slit die 2U and the downstream slit die 2L. Control to move to the set position together or separately. Further, the control unit 11 instructs the timing of supplying / stopping the coating liquid to the slit die 2.

The upstream gap H1 is the distance from the apex P1 of the upstream slit die 2U to the vertical lower surface of the base material 4 as shown in FIG.

The downstream gap H2 is the distance from the apex P2 of the downstream slit die 2L to the lower surface of the base material 4 in the vertical direction.

The configuration of the control unit 11 will be described.

FIG. 2A shows a state during coating at both ends of the base material 4 in the width direction.

In order to perform intermittent coating to form an uncoated portion C to which the coating liquid is not applied between the coating portion B to which the coating liquid is applied to the base material 4 and the coating portion B, the control unit 11 is used. Before stopping the supply of the coating liquid, first, as shown in FIG. 2B, the downstream slit die 2L is moved vertically downward so that the downstream gap H2 becomes large. The upstream slit die 2U does not move from the position during coating in FIG. 2 (a). As a result, the liquid pool moves to the downstream side. The amount of lowering the downstream slit die 2L vertically downward is about 0.01 mm or more and 0.5 mm or less.

After that, the control unit 11 moves the entire slit die 2 vertically upward to bring a part P3 of the upstream slit die 2U into contact with the lower surface of the base material 4 as shown in FIG. 2 (c).

After that, the control unit 11 stops the supply of the coating liquid to the slit die 2. When the supply of the coating liquid is stopped, as shown in FIG. 2D, the surface tension of the coating liquid exerts a force on the base material 4 in the direction of being drawn into the discharge port side of the slit die 2. A part of the base material 4 traveling in the transport direction 9 is displaced vertically downward.

After that, as shown in FIGS. 2 (e) and 2 (f), the coating liquid runs out with the passage of time. B is the bottom coating portion, and 10 is the end of the bottom coating portion B.

At a subsequent timing, the control unit 11 returns the upstream slit die 2U and the downstream slit die 2L to the upstream gap H1 and the downstream gap H2 shown in FIG. 2A, and repeats painting and intermittent coating.

FIG. 4A shows the operation of the slit die 2 during coating in the central portion in the width direction of the base material 4 when the control unit 11 operates the slit die 2 as shown in FIGS. 2A to 2F. ~ (F).

As shown in FIG. 4A, the upstream gap H1 and the downstream gap H2 during coating at the central portion in the width direction of the base material 4 are affected by the bending of the base material 4, and are similarly the base material as in FIG. 2A. It is narrower than both ends of 4.

If the downstream slit die 2L is moved vertically downward in FIG. 2B before the supply of the coating liquid is stopped, the liquid is also liquid in the central portion in the width direction of the base material 4 as shown in FIG. 4B. The pool moves to the downstream side.

When the entire slit die 2 is moved vertically upward in FIG. 2 (c), the upstream slit die 2U and the lower surface of the base material 4 are aligned with each other even in the central portion in the width direction of the base material 4 as shown in FIG. 4 (c). Upon contact, the coating gaps at both ends of the substrate become the same as in FIG. 2 (c).

After that, when the control unit 11 stops supplying the coating liquid to the slit die 2, as shown in FIG. 4D, the surface tension of the coating liquid causes the base material 4 to be on the discharge port side of the slit die 2. Since the force acts in the direction of being drawn into the base material 4, the base material 4 is displaced vertically downward. After that, as shown in FIGS. 4 (e) and 4 (f), the liquid runs out with the passage of time.

During the period from FIG. 2 (c) to FIG. 2 (e), a part P3 of the upstream slit die 2U is in contact with the base material 4 in all the width directions.

When the control unit 11 returns the upstream gap H1 and the downstream gap H2 at both ends of the substrate to the state of being coated as shown in FIGS. 2 (f) to 2 (a), the upstream gap H1 and the downstream of the central portion of the substrate are returned. The gap H2 returns to the state during coating in FIG. 4 (a). After that, painting and intermittent painting are repeated.

That is, it becomes possible to forcibly make all the coating gaps in the width direction constant, and as shown in FIG. 8, it is possible to manufacture a good battery electrode plate having no tailing at the end 10 of the lower surface coating portion B. Can be done.

In the first embodiment, after the downstream slit die 2L is lowered in FIG. 2B, the entire slit die 2 is raised in FIG. 2C to support the base material 4 by the upstream slit die 2U. Although the control unit 11 is configured to do so, the downstream slit die 2L starts descending from FIG. 2A, and the entire slit die 2 starts ascending before the downstream slit die 2L finishes descending. Then, the control unit 11 so as to bring the upstream slit die 2U into contact with the lower surface of the base material 4 to support the base material 4 with the upstream slit die 2U, and then stop the supply of the coating liquid to the slit die 2. The same effect can be expected even if the above is configured.

(Embodiment 2)
5 and 6 show the second embodiment. The configuration of the control unit 11 is different from that of the first embodiment. Others are the same as those in the first embodiment.

The configuration of the control unit 11 will be described with reference to FIG.

FIG. 5 shows the operation of the slit die 2 at both ends of the base material 4.

As shown in FIG. 5A, the upstream gap H1 and the downstream gap H2 are generally provided to be about 0.01 mm or more and 1.0 mm or less, although they differ depending on the characteristics of the coating liquid used.

FIG. 5A shows a state during coating. In order to perform intermittent coating, the control unit 11 moves the entire slit die 2 vertically upward as shown in FIG. 5B before stopping the supply of the coating liquid to the slit die 2. A part P3 of the upstream slit die 2U is brought into contact with the lower surface of the base material 4.

After that, as shown in FIG. 5C, the control unit 11 moves only the downstream slit die 2L vertically downward with a part of the slit die 2 in contact with the base material 4, so that the liquid pool is downstream. Move to the side. The amount of lowering the downstream slit die 2L vertically downward is about 0.01 mm or more and 0.5 mm or less.

After that, when the control unit 11 stops supplying the coating liquid to the slit die 2, as shown in FIG. 5D, the surface tension of the coating liquid causes the substrate to be drawn into the slit die discharge port side. Since the force acts in the direction of tension, a part of the base material 4 is displaced vertically downward.

Then, as shown in FIGS. 5 (e) and 5 (f), the liquid runs out with the passage of time. After that, the process is returned to the upstream gap H1 and the downstream gap H2 shown in FIG. 5A, and coating and intermittent painting are repeated.

6 (a) shows the operation of the slit die 2 during coating in the central portion in the width direction of the base material 4 when the control unit 11 operates the slit die 2 as shown in FIGS. 5 (a) to 5 (f). ~ (F).

As shown in FIG. 6A, the upstream gap H1 and the downstream gap H2 in the central portion of the base material 4 are narrower than both ends of the base material 4 due to the influence of the bending of the base material 4. However, in FIG. 4B, the control unit 11 moves the entire slit die 2 vertically upward to bring a part P3 of the upstream slit die 2U into contact with the lower surface of the base material 4, thereby causing the center of the base material 4. Even in the portion, a part P3 of the upstream slit die 2U comes into contact with the lower surface of the base material 4 as shown in FIG. 6 (b).

In FIG. 4 (c), the control unit 11 moves the downstream side slit die 2L vertically downward, so that the liquid pool moves to the downstream side even in the central portion of the base material 4 as shown in FIG. 6 (c). It will be the same as the coating gap at both ends of the material.

After that, when the control unit 11 stops supplying the coating liquid, as shown in FIG. 6D, a force is applied to the base material 4 in the direction of being drawn into the discharge port side of the slit die 2 by the surface tension of the coating liquid. Is working, so that a part of the base material 4 is displaced vertically downward.

After that, as shown in FIGS. 6 (e) and 6 (f), the liquid runs out with the passage of time. After that, the process is returned to the upstream gap H1 and the downstream gap H2 shown in FIG. 6A, and coating and intermittent painting are repeated.

That is, it becomes possible to forcibly make all the coating gaps in the width direction constant, and as shown in FIG. 8B, it is possible to manufacture a good battery electrode plate without tailing.

During the period from FIG. 5 (b) to FIG. 5 (e), a part P3 of the upstream slit die 2U is in contact with the base material 4 in all the width directions.

In the second embodiment, after the base material 4 is supported by the slit die 2 in FIG. 5 (b), the control unit 11 is configured so that the downstream slit die 2L starts the lowering operation in FIG. 5 (c). However, from FIG. 5A, the slit die 2 starts to rise, the downstream slit die 2L starts to descend before the upstream slit die 2U abuts on the base material 4, and the upstream side slit die 2U is used as the base material. The same effect can be expected even if the control unit 11 is configured to stop the supply of the coating liquid to the slit die 2 in a state of being in contact with the lower surface of the 4.

− Example −
The results of the implementation in the first and second embodiments are shown in Examples 1 and 2 below. Further, the prior art that does not use the present invention will be compared.

Common conditions for implementing this example are described below.

The slit die 2 is made of stainless steel SUS430 and has a tip width of 1 mm for the upstream slit die 2U, a tip width of 1 mm for the downstream slit die 2L, and a gap of 0.5 mm between the upstream slit die 2U and the downstream slit die 2L. I used the one. As the base material 4, an electrolytic copper foil YB-10 (thickness 0.01 mm) manufactured by Nippon Denkai Co., Ltd. was used by slitting it to a width of 70 mm. As the coating liquid, a slurry having a viscosity of about 6000 cP measured under the condition of a rotation speed of 20 rpm with a B-type viscometer was used. The slurry was sent at 11.7 g / min by a MONO pump manufactured by Hyojin Equipment Co., Ltd., and discharged from the slit die 2 at a width of 45 mm to form a coating film. The substrate transfer speed was 1 m / min, the tension was 15 N, and the coating was applied at 1000 m. The amount of lowering the downstream slit die 2L vertically downward was set to 0.05 mm.

In addition, in the judgment of the quality of the tail pull, the tail pull length exceeding Y = 1.5 mm was defined as a defect. Hereinafter, examples of the present invention will be described, which are only a few of the embodiments of the present invention.

(Example 1)
In the first embodiment, the upstream gap H1 = 0.24 mm and the downstream gap H2 = 0.3 mm in the central portion of the base material before the start of coating are set. At this time, both ends of the base material have an upstream gap H1 = 0.34 mm and a downstream gap H2 = 0.4 mm, and the base material 4 has a difference of 0.1 mm between the central portion and both ends due to the influence of bending. The results are shown in Table 1.

As shown in Table 1, the tailing defect rate was 1.5% in the prior art, whereas the tailing defect rate was 0% in the first embodiment.

In this way, by forcibly making the coating gap in all width directions constant, a good battery electrode plate with no tailing even if the difference in deflection of the base material between both ends and the center is 0.1 mm can be obtained. It was confirmed that it could be manufactured.

（実施例２）
実施の形態２で、塗工開始前における基材中央部の上流ギャップＨ１＝０．２ｍｍ、下流ギャップＨ２＝０．２６ｍｍに設定した。この時の基材両端部は、上流ギャップＨ１＝０．２８ｍｍ、下流ギャップＨ２＝０．３４ｍｍであり、基材は撓みの影響で中央部と両端部で０．０８ｍｍの差がある。結果を表２に示す。表２に示すように、従来技術では尾引き不良率１．５％に対して、本発明では尾引き不良率０％であった。このように、幅方向全ての塗工ギャップを強制的に一定にすることで、両端部と中央部で基材の撓みの差が０．０８ｍｍあっても尾引きが無い良好な電池極板を製造することができることを確認した。

(Example 2)
In the second embodiment, the upstream gap H1 = 0.2 mm and the downstream gap H2 = 0.26 mm in the central portion of the base material before the start of coating are set. At this time, both ends of the base material have an upstream gap H1 = 0.28 mm and a downstream gap H2 = 0.34 mm, and the base material has a difference of 0.08 mm between the central portion and both ends due to the influence of bending. The results are shown in Table 2. As shown in Table 2, the tailing defect rate was 1.5% in the prior art, whereas the tailing defect rate was 0% in the present invention. In this way, by forcibly making the coating gap in all width directions constant, a good battery electrode plate with no tailing even if the difference in deflection of the base material between both ends and the center is 0.08 mm can be obtained. It was confirmed that it could be manufactured.

Since the coating method of the present invention can intermittently form a coating film on both sides of the base material, it is possible to realize an increase in capacity of the lithium ion secondary battery electrode plate at low cost.

1 Slit die for bottom coating 2 Slit die for bottom coating 2U Slit die on the upstream side 2L Slit die on the downstream side 3 Base material support device 4 Base material 5 Tailing 6 Drying device 7 Backup roll 8 Liquid pool 9 Transport direction 10 Coating End of part 11 Control part B Painted part C Unpainted part P1 Top of upstream slit die 2U P2 Top of downstream slit die 2L P3 Part of upstream slit die 2U H1 Upstream gap H2 Downstream gap

Claims (8)

It is a coating method that intermittently forms a coating film on a base material.
Above the discharge port between the upstream side slit die of the slit die arranged facing the lower surface of the base material and the downstream side slit die of the slit die with respect to the horizontally running base material. A coating film is formed on the lower surface of the base material by discharging the coating liquid toward the substrate.
The downstream slit die is moved downward without changing the distance between the upstream slit die of the slit die and the lower surface of the base material.
After that, the slit die is moved upward so that the upstream slit die is brought into contact with the lower surface of the base material.
After that, the supply of the coating liquid to the slit die was stopped, and the supply was stopped.
A coating method for drying the coating film. It is a coating method that intermittently forms a coating film on a base material.
Above the discharge port between the upstream side slit die of the slit die arranged facing the lower surface of the base material and the downstream side slit die of the slit die with respect to the horizontally running base material. A coating film is formed on the lower surface of the base material by discharging the coating liquid toward the substrate.
The entire downstream slit die begins to ascend before the downstream slit die begins to descend, and the entire slit die begins to ascend, and the upstream slit die is brought into contact with the lower surface of the substrate.
After that, the supply of the coating liquid to the slit die was stopped, and the supply was stopped.
A coating method for drying the coating film. It is a coating method that intermittently forms a coating film on a base material.
Above the discharge port between the upstream side slit die of the slit die arranged facing the lower surface of the base material and the downstream side slit die of the slit die with respect to the horizontally running base material. A coating film is formed on the lower surface of the base material by discharging the coating liquid toward the substrate.
The slit die is moved upward so that the upstream slit die is brought into contact with the lower surface of the base material.
After that, the downstream slit die is moved downward to move it downward.
With the upstream slit die in contact with the lower surface of the base material, the supply of the coating liquid to the slit die is stopped.
A coating method for drying the coating film. It is a coating method that intermittently forms a coating film on a base material.
Above the discharge port between the upstream side slit die of the slit die arranged facing the lower surface of the base material and the downstream side slit die of the slit die with respect to the horizontally running base material. A coating film is formed on the lower surface of the base material by discharging the coating liquid toward the substrate.
The ascending of the slit die is started, and the descending of the downstream slit die is started before the upstream slit die comes into contact with the base material.
With the upstream slit die in contact with the lower surface of the base material, the supply of the coating liquid to the slit die is stopped.
A coating method for drying the coating film. The state in which the upstream slit die is in contact with the lower surface of the base material is characterized in that the upstream slit die is in contact with the lower surface of the base material in all the width directions of the base material.
The coating method according to any one of claims 1 to 4. It is a coating device that intermittently forms a coating film on a base material that is running from good to bad.
A slit die for supplying the coating solution to the surface of the lower of the substrate from the discharge port between the upstream side slit die and the downstream slit die,
Before stopping the supply of the coating liquid to the slit die, a control unit for instructing the slit die to move the slit die on the upstream side of the slit die so as to contact and support the lower surface of the base material. have a,
The control unit
The slit die is moved upward so that the upstream slit die is brought into contact with the lower surface of the base material.
After that, the downstream slit die is moved downward to move it downward.
A coating apparatus , characterized in that the supply of the coating liquid to the slit die is stopped in a state where the upstream slit die is in contact with the lower surface of the base material. It is a coating device that intermittently forms a coating film on a base material that is running from good to bad.
A slit die for supplying the coating solution to the surface of the lower of the substrate from the discharge port between the upstream side slit die and the downstream slit die,
Before stopping the supply of the coating liquid to the slit die, a control unit for instructing the slit die to move the slit die on the upstream side of the slit die so as to contact and support the lower surface of the base material. have a,
The control unit
The lower side slit die is started to descend, and the lower side slit die is started to descend.
Before the downstream slit die finishes descending, the entire ascending of the slit die is started.
Then, the upstream slit die is brought into contact with the lower surface of the base material, and the slit die is brought into contact with the lower surface of the base material.
After that, the coating apparatus is characterized in that the supply of the coating liquid to the slit die is stopped. It is a coating device that intermittently forms a coating film on a base material that is running from good to bad.
A slit die for supplying the coating solution to the surface of the lower of the substrate from the discharge port between the upstream side slit die and the downstream slit die,
Before stopping the supply of the coating liquid to the slit die, a control unit for instructing the slit die to move the slit die on the upstream side of the slit die so as to contact and support the lower surface of the base material. have a,
The control unit
The rise of the slit die is started, and the slit die is started to rise.
Before the upstream slit die comes into contact with the base material, the downstream slit die is started to descend.
A coating apparatus , characterized in that the supply of the coating liquid to the slit die is stopped in a state where the upstream slit die is in contact with the lower surface of the base material.

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