JP2019145420A - Manufacturing method of battery electrode plate, and coating device - Google Patents

Abstract

To form a battery electrode plate with a satisfactory shape of an intermittent terminal while coating a substrate with a coating liquid in an intermittent manner using a slit die.SOLUTION: A manufacturing method for a battery electrode plate includes: iteratively forming a bottom face coated part 4 and a non-coated part 5 by discharging a coating liquid to a traveling substrate 3 in an intermittent manner by a slit die 1 of which the discharge port is disposed oppositely to a bottom face of the substrate 3; and drying the substrate 3 in which the bottom face coated part 4 is coated, by passing a drying device. In accordance with the manufacturing method of the battery electrode plate, an operation for narrowing a gap with the substrate 3 in an upstream end HU of a distal end of the slit die 1 without changing a gap with the substrate 3 in a downstream end HL of the distal end of the slit die 1 is started or completed in timing T2 prior to timing Ts to stop the coating liquid from the discharge port of the slit die 1, and supply of the coating liquid to the slit die 1 is stopped thereafter in the timing Ts. Thus, a liquid drainage property is also improved while suppressing the movement of pulling the substrate into the coating liquid in the intermission, and linearity of a coating terminal is improved.SELECTED DRAWING: Figure 2

Description

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

  A battery electrode plate used for a lithium ion secondary battery or the like is a coating solution containing an active material, a binder, a thickener, and a solvent with respect to a plate-like substrate conveyed from a supply roll to a take-up roll. Is discharged from the tip of the die to form a coating film having a uniform thickness and dried. The battery is configured by sandwiching a separator between a positive electrode plate and a negative electrode plate and winding or laminating the separator together with an electrolyte in a can.

  In recent years, with the spread of in-vehicle batteries, high capacity and safety have become issues, and it is important how to manufacture an electrode plate having a uniform thickness and high density coating film. .

  In order to increase the capacity of the battery, it is necessary to increase the amount of active material while reducing the amount of base material used. For that purpose, it is necessary to form a coating film on both surfaces of the substrate.

  In addition, as the price goes down, how to increase productivity is a problem for each company, and various technologies are being developed.

  For example, a coating film is formed on the upper surface of a base material while supporting the base material with a backup roll, and after drying with a drying apparatus, the surface of the base material is reversed, and the base material is supported while the base material is supported with a backup roll. A method of forming a coating film on the lower surface has been proposed.

  Although this method can stably produce a coating film, it requires two drying steps, and it is necessary to turn the substrate upside down when forming a coating film on the lower surface of the substrate. There are problems such as a long process, a space required, and the productivity is limited.

  As a method for solving this problem, Patent Document 1 discloses that a slit die discharge port is disposed to face each other, and a coating film is formed on both surfaces of the substrate while simultaneously discharging the coating liquid. There has been proposed a method in which electrode plates are collectively formed on both surfaces of a substrate by simultaneously drying the formed coating film.

  However, in this method, when the discharge pressure is different for each slit die, there is a problem that the position of the base material is easily deformed due to the influence, and the coating thickness of the coating liquid on the upper surface and the lower surface is different.

  Further, in Patent Document 2, a coating film is formed on the upper surface of the base material by a slit die while the base material is supported by a backup roll, the base material is transported in the horizontal direction, and vertically upward on the vertical lower surface of the base material. A method has been proposed in which a die having a discharge port is installed and a coating film is formed on the lower surface of the substrate to form electrode plates on both surfaces of the substrate in a lump.

  In the method of Patent Document 2, although it is difficult to be affected by the coating thickness due to the difference in discharge pressure between the two slit dies, it is suitable for continuously forming a coating film, but a discharge film was formed. The problem is that the shape of the end of the coated part deteriorates when intermittent coating is performed in which the coated part and the uncoated part on which no discharge film is formed are alternately formed in the longitudinal direction of the substrate. There is.

  This will be described with reference to FIGS.

  As for the conveyance of the double-sided coated base material, the coated surface is wet until the coating surface is completely dried after the coating is completed almost simultaneously, so the substrate can be supported by a long roll or the like. Can not. Therefore, a mechanism for gripping both edges in the width direction of the base material 3 is provided, or the base material is floated and conveyed by jetting gas from above and below the base material in the drying apparatus. Due to the influence of the weight of the applied coating liquid, the substrate 3 being conveyed is easily bent in the width direction as shown in FIG. 12, and in particular, the center portion in the width direction of the substrate 3 is on both edges of the substrate 3. In comparison, since it bends by H1 downward and is conveyed in an unstable state in the vertical direction, the coating state is different between both edge portions of the substrate 3 and the central portion in the width direction. Reference numeral 9 denotes the conveyance direction of the substrate 3.

  T <b> 1 to T <b> 5 in FIG. 13A indicate the progress of the coating state at both edges of the substrate 3. T <b> 1 to T <b> 6 in FIG.

  In the case where a coating film is formed by discharging the coating liquid from the slit die 1 without using a backup roll onto the thin plate-like substrate 3 being conveyed in the horizontal direction, the slit die 1 is formed at both edges of the substrate 3. As shown in T2 to T5 in FIG. 13A immediately after stopping the coating liquid being discharged from, the liquid pool is interrupted and the surface tension is reduced even after the discharge of the coating liquid from the slit die 1 is stopped. The substrate 3 is conveyed without being drawn into the behavior.

  On the other hand, in the central portion in the width direction of the base material 3, since the base material 3 is easily bent and the vertical position is unstable, the discharge of the coating liquid is stopped as indicated by T <b> 2 to T <b> 6 in FIG. The base 3 is drawn into a behavior that the liquid pool is interrupted later and tends to shrink due to surface tension, and the timing at which the liquid pool is interrupted is delayed as compared with the behavior in the vicinity of both edge portions of the base 3. Since the base material 3 and the coating liquid are kept in contact with each other during this period, the liquid sharpness in the center in the width direction is delayed. Therefore, as shown in FIG. 14, the shape of the coating film of the terminal end 4e of the coating part 4 deteriorates in circular arc shape. Y indicates the tailing length.

Japanese Patent No. 4354598 WO2011 / 001648A1

  As a method of improving the terminal shape at the time of intermittent coating, not only the discharge of the coating liquid from the slit die 1 but also the discharge of the coating liquid from the slit die 1 and the slit die and the substrate 3 are stopped. It is conceivable to change the gap (hereinafter referred to as a coating gap).

  The case where it coats on the upper surface of the base material 3 with a backup roll is shown to Fig.15 (a)-(d). The upper stage (1) of FIG. 15 (a) is a side view of a liquid reservoir at the discharge port of the slit die 1 in the coating state, and the middle stage (2) in FIG. 15 (a) is the slit die 1 in the coating state. The figure which looked at the liquid pool in the discharge port of this from the upper side of the conveyance direction 9 is shown. The lower part (3) of FIG. 15A shows the shape of the upper surface coating part 6 being applied to the substrate 3.

  15A is a side view of a liquid pool at the discharge port of the slit die 1 when the discharge of the coating liquid from the slit die 1 is stopped while the coating gap is left as it is from the state of being applied in FIG. This is shown in the upper part (1) of FIG. The middle stage (2) of FIG. 15B shows the liquid pool at that time as viewed from the transport direction 9. The lower part (3) of FIG. 15 (b) shows the tailing of the terminal end 6 e of the upper surface coating part 6 of the substrate 3.

  FIG. 15A is a side view of a liquid pool at the discharge port of the slit die 1 when the coating gap is increased from the state of application in FIG. 15A and the discharge of the coating liquid from the slit die 1 is stopped. It is shown in the upper part (1) of 15 (c). The middle part (2) of FIG. 15C shows the liquid reservoir at that time as viewed from the transport direction 9. The lower part (3) of FIG. 15 (c) shows the tailing of the terminal end 6e of the upper surface coating part 6 of the substrate 3.

  FIG. 15A is a side view of a liquid pool at the discharge port of the slit die 1 when the coating gap is reduced from the state of FIG. 15A being applied and the discharge of the coating liquid from the slit die 1 is stopped. It is shown in the upper part (1) of 15 (d). The middle part (2) of FIG. 15 (d) shows the liquid reservoir at that time as viewed from the transport direction 9. The lower part (3) of FIG. 15 (d) shows the tailing of the end 6 e of the upper surface coating part 6 of the base material 3.

  The case where it coats to the lower surface of the base material 3 without using a backup roll is shown to Fig.16 (a)-(d). The upper stage (1) of FIG. 16A is a side view of a liquid pool at the discharge port of the slit die 1 in the coating state, and the middle stage (2) in FIG. 16A is the slit die 1 in the coating state. The figure which looked at the liquid pool in the discharge port of this from the upper side of the conveyance direction 9 is shown. The lower part (3) of FIG. 16 (a) shows the shape of the lower surface coating portion 4 being applied to the substrate 3.

  16A is a side view of a liquid reservoir at the discharge port of the slit die 1 when the discharge of the coating liquid from the slit die 1 is stopped while the coating gap is left as it is from the state of being applied in FIG. This is shown in the upper part (1) of FIG. The middle stage (2) of FIG. 16B shows the liquid pool at that time as viewed from the transport direction 9. The lower part (3) of FIG. 16 (b) shows the tailing of the end 4 e of the lower surface coating part 4 of the substrate 3.

  16A is a side view of a liquid pool at the discharge port of the slit die 1 when the coating gap is increased from the state of being applied in FIG. 16A and the discharge of the coating liquid from the slit die 1 is stopped. It is shown in the upper part (1) of 16 (c). The middle part (2) of FIG. 16C shows the liquid reservoir at that time as viewed from the transport direction 9. The lower part (3) of FIG. 16 (c) shows the tailing of the terminal end 4 e of the lower surface coating part 4 of the substrate 3.

  FIG. 16A is a side view of a liquid pool at the discharge port of the slit die 1 when the coating gap is reduced from the state of FIG. 16A being applied and the discharge of the coating liquid from the slit die 1 is stopped. The upper part (1) of 16 (d) is shown. The middle stage (2) of FIG. 16D shows the liquid pool at that time as viewed from the transport direction 9. The lower part (3) of FIG. 16 (d) shows the tailing of the terminal end 4e of the lower surface coating part 4 of the substrate 3.

  In the case of coating on the upper surface of the substrate 3 with a backup roll as shown in FIG. 15, the substrate 3 at the slit die discharge port is held in close contact with the backup roll. The change in the coating gap due to the change in the substrate position does not occur.

  Therefore, when the discharge is stopped by stopping the discharge of the coating liquid from the state during coating shown in FIG. 15 (a), as shown in FIGS. 15 (b) and (2), the width direction from both edges in the width direction. Since the end 6e of the upper surface coating portion 6 is formed by the liquid pool being interrupted toward the center, the liquid center is delayed in the center in the width direction compared to the periphery of both edges in the width direction, and the arc-shaped end shape It becomes. The degree of the arc shape is also affected by the physical properties of the coating liquid such as viscosity and surface tension, and the wettability relationship between the coating liquid and the base 3 and the tip of the slit die 1.

  Therefore, as shown in FIG. 15 (c), when the slit die 1 is raised in accordance with the stop of the discharge of the coating liquid to widen the coating gap, the liquid pool is interrupted as shown in FIGS. 15 (c) and (2). As shown in FIG. 15D, the degree of the end 6e having an arc shape is reduced, so that the linearity of the end 6e of the upper surface coating portion 6 is improved.

  As a change in the coating gap in accordance with the stop of the discharge of the coating liquid, it is conceivable to lower the slit die 1 in accordance with the stop of the discharge to narrow the coating gap. In that case, FIG. As shown in 2), since the liquid pool of the die head discharge part is crushed toward the base material 3, the application width of the upper surface coating part 6 is widened as shown in FIGS. 15 (d) and (3). Usually, a method is used in which the slit die 1 is raised to widen the coating gap in accordance with the stoppage of the coating liquid discharge.

  Similarly, when the coating is performed on the lower surface of the base material 3 without using the backup roll, the discharge of the coating liquid is stopped from the coating state shown in FIG. When intermittent, the base material 3 is easily bent in the width direction, and in particular, the center part in the base material width direction is transported in an unstable state in the vertical direction, so as shown in FIGS. In the behavior where the liquid pool is interrupted from both edges in the width direction toward the center in the width direction, the liquid pool is interrupted and drawn into the behavior of trying to shrink due to surface tension, and the liquid pool is interrupted in the center in the width direction Since the timing is greatly delayed as compared with the vicinity of the end in the width direction, the end 4e becomes a very large arc as shown in FIGS.

  Therefore, as shown in FIG. 16 (c), when the slit die 1 is lowered in accordance with the stop of the discharge of the coating liquid to widen the coating gap, as shown in FIGS. Although the interruption can be promoted and the extent that the end 4e of the lower surface coating portion 4 becomes arcuate as shown in FIGS. 16 (c) and (3) is reduced compared to FIGS. 16 (b) and (3), the backup roll There exists a problem that it will deteriorate compared with the case where it coats on the upper surface of the base material 3 (FIG.15 (c) (3)).

  As shown in FIG. 16 (d), when the slit die 1 is raised in accordance with the stop of the discharge of the coating liquid to narrow the coating gap, as in FIGS. 15 (d) and (3), FIG. As shown in (2), the liquid pool in the die head discharge part is crushed toward the substrate 3 side, and the application width at the end 4e of the lower surface coating part 4 is as shown in FIGS. 16 (d) and (3). In order to spread, normally, the method of expanding the coating gap by lowering the slit die 1 in accordance with the stop of the discharge of the coating liquid is used.

  Accordingly, in view of the above problems, the present invention provides a battery electrode having excellent linearity at the end of the lower surface coating portion while applying a coating liquid intermittently and uniformly on a substrate using a slit die. It aims at providing the manufacturing method of a battery electrode plate which can form a board.

  The method for producing a battery electrode plate of the present invention is such that a coating liquid is intermittently discharged to a traveling substrate by a slit die arranged so that a discharge port faces the lower surface of the substrate. And a non-coated portion is repeatedly formed, and the base material coated with the lower surface coated portion is dried by passing through a drying device, the method comprising: Before stopping the coating liquid, the gap between the slit die and the upstream end of the slit die is narrowed without changing the gap between the slit die and the downstream end of the slit die. The operation is started or completed, and thereafter, the supply of the coating liquid to the slit die is stopped.

  Moreover, it is more preferable that the base material has an upper surface coating part before drying by applying a coating liquid on the upper surface before forming the lower surface coating part.

  In addition, after stopping the supply of the coating liquid to the slit die, without changing the clearance between the upstream end of the slit die and the base material, the downstream end of the slit die It is more preferable to widen the gap with the substrate.

  Further, in a state where the gap between the upstream end of the slit die tip and the base material is narrowed without changing the gap between the downstream end of the slit die tip and the base material, More preferably, the upstream end of the tip is brought into contact with the lower surface of the substrate.

  It is more preferable to change the gap with the base material by changing the angle of the slit die with respect to the base material.

  The battery electrode plate coating apparatus of the present invention is a lower surface coating method in which a coating liquid is intermittently discharged to a traveling substrate by a slit die arranged so that a discharge port faces the lower surface of the substrate. In the battery electrode coating device, the substrate coated with the lower surface coating portion is dried by passing through a drying device, and is formed downstream of the tip of the slit die. Provided with a position changing unit that can individually change the gap between the base material at the end and the base material at the upstream end, and before the stop of the coating liquid from the discharge port of the slit die The operation of starting or completing the operation to narrow the gap between the upstream end of the slit die tip and the base material without changing the gap between the downstream end of the slit die tip and the base material is performed. , And then configured to stop the supply of the coating liquid to the slit die, And wherein the door.

  Further, the base material is provided with a second slit die that forms a top surface coating portion before drying by applying a coating liquid on the top surface of the base material before forming the bottom surface coating portion. It is more preferable.

  In addition, the position changing unit, after stopping the supply of the coating liquid to the slit die, without changing the gap between the upstream end of the slit die and the base material, It is more preferable to widen the gap between the downstream end of the tip and the base material.

  In addition, the position changing unit is a state in which the gap between the base end at the upstream end of the slit die is narrowed without changing the gap between the base end at the downstream end of the slit die front end. Then, it is more preferable that the upstream end of the front end portion of the slit die is brought into contact with the lower surface of the base material.

  More preferably, the position changing unit changes the gap with the base material by changing an angle of the slit die with respect to the base material.

  According to this configuration, the operation of starting or operating to narrow the gap between the upstream end of the slit die and the upstream end of the slit die without changing the gap between the downstream end of the slit die and the base is performed. After that, the supply of the coating liquid to the slit die is stopped, so that a coating film can be formed intermittently with a uniform film thickness and a battery electrode plate with good shape linearity at the intermittent part is manufactured. can do.

The block diagram of the coating apparatus which enforces the manufacturing method of the battery electrode plate of this invention (A) The figure which shows the behavior of the liquid pool in the width direction edge part vicinity of the base material 3 in the slit die front-end | tip part at the time of an intermittent, (b) The figure which shows the behavior of the liquid pool in the width direction center part Operation flow diagram regarding the gap between the upstream end HU and the downstream end HL of the base 3 and the supply stop timing of the coating liquid at the tip end of the slit die Plan view showing the terminal shape of the bottom coating part Operation flow diagram showing (a) the behavior of the liquid pool in the vicinity of both edges in the width direction of the substrate 3 and (b) the behavior of the liquid pool in the center portion in the width direction in the second embodiment of the present invention. (A) The figure which shows the behavior of the liquid pool in the width direction both edge part vicinity of the base material 3 at the time of the intermittent in Embodiment 3 of this invention, and (b) The operation | movement which shows the behavior of the liquid pool in the width direction center part Flow diagram Operation flow diagram regarding the gap between the upstream end HU and the downstream end HL of the base material 3 at the tip end portion of the embodiment and the supply stop timing of the coating liquid (A) The figure which shows the behavior of the liquid pool in the width direction edge part vicinity of the base material 3 in Embodiment 4 of this invention, (b) The operation | movement flowchart which shows the behavior of the liquid pool in the width direction center part The block diagram of the coating apparatus of Embodiment 5 which enforces the manufacturing method of the battery electrode plate of this invention. Operation flow diagram showing another specific example of each of the above embodiments When the supply of the coating liquid is stopped while changing the upstream end HU at the slit die tip, the gap between the upstream end HU and the downstream end HL at the slit die tip and the base material 3 and the coating liquid Operation flow chart for supply stop timing Sectional drawing of the width direction which shows the state of the bending of the base material 3 in conveyance (A) T1-T5 shows the progress of the coating state at both edges of the base material 3, and (b) T1-T6 shows the progress of the coating state at the center in the width direction of the base material 3. The top view which shows the upper surface coating part 6 formed in the base material 3 (A) a liquid reservoir during coating of the upper surface coating portion 6 using a backup roll; (b) a liquid reservoir in which the coating gap is the same as during coating and the discharge of the coating liquid is stopped; and (c). The upper part (1) of the liquid reservoir in which the coating gap is increased and the ejection of the coating liquid is stopped, and (d) the liquid reservoir in which the coating gap is reduced and the ejection of the coating liquid is stopped is a side view, middle stage (2) is a view from the upper side, lower (3) is a plan view (A) a liquid pool during coating of the lower surface coating portion 4 without using a backup roll; (b) a liquid pool where the coating gap is the same as during coating and the discharge of the coating liquid is stopped; The upper stage (1) of the liquid reservoir that increased the coating gap and stopped discharging the coating liquid, and (d) the liquid pool that decreased the coating gap and stopped discharging the coating liquid. The middle (2) is seen from the upper side, the lower (3) is a plan view

  Hereinafter, the manufacturing method of the battery electrode plate of the present invention will be described based on each specific embodiment.

(Embodiment 1)
The first embodiment of the present invention will be described below.

  FIG. 1 shows a coating apparatus 8 that forms a coating film on the lower surface of a substrate 3 that runs horizontally.

  The coating apparatus 8 transports the base material 3 supplied from an unwinder (not shown) in the horizontal direction at a constant speed via the transport roll 7, and is based on the downstream side of the transport direction 9 from the transport roll 7. The coating liquid is intermittently applied to the lower surface of the base material 3 in the longitudinal direction of the base material 3 by the slit die 1 installed vertically below the material 3. As a result, the lower surface coated portion 4 coated with the coating liquid and the uncoated portion 5 not coated with the coating liquid are repeatedly formed on the lower surface of the substrate 3.

  In the base material 3 on which the lower surface coating portion 4 and the uncoated portion 5 are repeatedly formed, the coating liquid applied through the drying device 16 is dried and collected by a winder (not shown). The

  A tank 10, a pump 11, and a valve 12 are connected to the slit die 1 in series in the order described, and a fixed amount of coating liquid is supplied, so that a fixed amount is discharged from the discharge port of the slit die 1 and has a uniform thickness. The coating film is formed.

  The slit die 1 is installed with a coating gap space with respect to the substrate 3. Although it varies depending on the characteristics of the coating liquid used, the coating gap is set to about 0.01 to 1.0 mm. The pump 11 needs to supply the coating liquid quantitatively and continuously to the slit die 1. For example, there are a screw pump and a diaphragm pump, and the screw pump is often selected in consideration of pulsation.

  Although not shown in detail, the valve 12 includes a reservoir and a valve unit. After the coating liquid supplied from the pump 11 enters the reservoir through the channel, the valve 12 passes through the channel to the valve unit. Thereafter, the flow path is divided into two and discharged from the valve. The valve section is branched into a flow path toward the slit die 1 and a flow path toward the tank 10, and the pump 11 feeds the coating liquid continuously and quantitatively while the valve section of the valve 12 is moved to the air cylinder. By switching between the two, the coating liquid toward the slit die 1 side is circulated to the tank 10 side at the time of intermittent operation, and intermittent coating can be realized.

  The tank 10 is always filled with a coating solution at normal temperature and pressure, and is supplied to the pump 11. Although depending on the amount of coating liquid supplied from the pump 11, it is desirable to always stir with a mixer (not shown) when using a coating liquid that easily settles.

  The position of the slit die 1 during operation of the coating apparatus 8 is controlled by the position changing unit 17. The position changer 17 controls the clearance between the upstream end HU and the downstream end HL of the base 3 of the slit die 1 when approaching the end 4e of the lower surface coating portion 4, and the tip of the slit die The gap between the downstream end HL of the part and the base material 3 and the gap between the upstream end HU and the base material 3 can be individually changed.

  The configuration of the position changing unit 17 will be described based on the operation flow of FIG. 2 and FIG.

  FIG. 2A shows the behavior of the liquid pool in the vicinity of both edges in the width direction of the base material 3 when the position of the slit die 1 is controlled by the position changing unit 17 from T1 to T6. T1 indicates the posture of the slit die 1 during coating. At this time, the gaps between the upstream end HU and the downstream end HL at the front end of the slit die 1 and the lower surface of the base material 3 are the same, and are set to a coating gap necessary for forming a coating film having a target thickness. . The timing of stopping the supply of the coating liquid from the valve 12 to the slit die 1 is set to Ts between T2 and T3 shown in FIG. T6 indicates the timing at which the supply of the coating liquid from the slit die 1 to the substrate 3 is completed at the end 4e of the lower surface coating portion 4. FIG. 2B shows the behavior of the liquid pool at the center in the width direction when the attitude of the slit die 1 is controlled in this way.

  During the coating shown in FIGS. 2 (a) T1 and 2 (b) T1, the posture of the slit die 1 is at T2 before the timing Ts of stopping the supply of the coating liquid from the valve 12 to the slit die 1. First, as shown in FIGS. 2A and 2B, by changing the angle of the slit die relative to the substrate 3 with the downstream end HL of the slit die tip as a fulcrum, The gap between the downstream end HL and the base material 3 is not changed, and the gap between the upstream end HU and the base material 3 is narrowed in the period of T1 to T2. In the period from T2 to T6, the upstream end HU at the tip of the slit die 1 is not in contact with the lower surface of the substrate 3. The gap between the upstream end HU and the base material 3 is the same as the gap between the downstream end HL and the base material 3 at a timing after T6 when the supply of the coating liquid from the slit die 1 to the base material 3 is completed. Return to

  Thus, since the volume of the liquid pool between the slit die tip and the base material 3 is reduced by narrowing the gap between the upstream end HU and the base material 3 by T2 to T6, the base material 3 bends. Even in the center portion in the width direction of the base material 3 which is easy to move up and down easily, the behavior drawn by the surface tension of the liquid pool during the intermittent operation is limited. Therefore, it is possible to suppress a delay in the timing at which the liquid pool is interrupted in the central portion in the width direction compared to the behavior in the vicinity in the width direction end portion, and the linearity at the end 4e as described in FIGS. 13 and 14 is deteriorated. Therefore, a battery electrode plate having a good intermittent shape as shown in FIG. 4 can be formed.

  Further, the gap between the downstream end HL and the base material 3 is not changed, and the gap between the upstream end HU and the base material 3 is narrowed, so that the clearance between the downstream end HL and the base material 3 is secured. Therefore, there is no problem that the coating width at the end is widened as shown in FIGS. 15 (d) (3) and 16 (d) (3).

(Embodiment 2)
FIG. 5 shows an operation flow of the second embodiment.

  In the position changing unit 17 according to the first embodiment, as shown in FIGS. 2A and 2B, the upstream end HU at the tip end of the slit die is not in contact with the lower surface of the substrate 3 at T2 to T6. . On the other hand, the second embodiment is different from the first embodiment only in that the upstream end HU at the slit die tip is in contact with the lower surface of the substrate 3.

  FIG. 5A shows the behavior of the liquid pool in the vicinity of both edges in the width direction of the substrate 3, and FIG. 5B shows the behavior of the liquid pool in the center portion in the width direction.

  During the coating shown in FIGS. 5 (a) T1 and FIG. 5 (b) T1, the posture of the slit die 1 is at T2 before the supply stop timing Ts of the coating liquid from the valve 12 to the slit die 1. First, as shown in FIGS. 5 (a) T 2 and FIG. 5 (b) T 2, the angle of the slit die 1 with respect to the substrate 3 is changed using the downstream end HL of the slit die tip as a fulcrum. At this time, the slit die 1 is rotated until the upstream end HU of the tip end portion of the slit die contacts the lower surface of the substrate 3. This state in which the upstream end HU of the slit die tip is in contact with the lower surface of the substrate 3 continues until T6.

  In this way, by bringing the upstream end HU of the slit die tip portion into contact with the base material 3, the volume of the liquid pool between the slit die tip portion and the base material 3 can be further reduced as compared with the first embodiment. In addition, since the effect of supporting the base material 3 from the lower side is also obtained, the base material 3 is easily bent and has a behavior of being drawn by the surface tension of the liquid pool during the intermittent operation in the center in the width direction of the base material 3. This can be further limited as compared with the first embodiment.

  In the case of Embodiment 1 where the gap between the upstream end HU and the downstream end HL at the slit die tip in Embodiment 2 and the supply stop timing of the coating liquid are qualitatively illustrated, This is the same as FIG.

(Embodiment 3)
6 and 7 show the third embodiment.

  In the position changing unit 17 according to the first embodiment, as shown in FIGS. 2A and 2B, in T2 to T6, the downstream end HL at the slit die tip is the same position as the downstream end HL in T1. Thus, the gap between the slit die tip and the lower surface of the substrate 3 was the same in T2 to T6. In contrast, in the third embodiment, at T5 to T6, the downstream end HL rotates in the direction of widening the gap between the downstream end HL and the substrate 3 with the upstream end HU serving as a fulcrum. Only the difference is from the first embodiment.

  FIG. 6A shows the behavior of the liquid pool in the vicinity of both edges in the width direction of the substrate 3, and FIG. 6B shows the behavior of the liquid pool in the center portion in the width direction. FIG. 7 shows the gap between the upstream end HU and the downstream end HL at the tip end of the slit die in the third embodiment and the supply stop timing of the coating liquid.

  As shown in FIGS. 6 and 7, during the coating shown in FIGS. 6 (a) T1 and 6 (b) T1, as shown in FIGS. 6 (a) T2 and 6 (b) T2, the slit die By changing the angle of the slit die 1 with respect to the substrate 3 with the downstream end HL of the tip as a fulcrum, the gap between the downstream end HL and the substrate 3 at the tip of the slit die is not changed, and the upstream end HU The gap with the base material 3 is narrowed, and then the supply of the coating liquid is stopped. Further, as shown in FIGS. 6 (a) T5 and T6 and FIGS. 6 (b) T5 and T6, the angle of the slit die with respect to the substrate 3 is changed with the upstream end HU of the slit die tip as a fulcrum. The gap between the downstream end HL and the substrate 3 is widened without changing the gap between the upstream end HU and the substrate 3 at the tip of the slit die.

  As described above, in T5 to T6, by widening the gap between the downstream end HL and the base material 3 at the slit die tip, it is possible to promote the breakage of the liquid accumulation at the slit die discharge port, so that the vicinity of the width direction end Compared to the first embodiment, it is possible to further suppress the behavior that the timing at which the liquid pool is interrupted in the central portion in the width direction is delayed. As a result, even in the case of a coating condition with a heavy coating weight or a thin base material 3 that is particularly prone to bend, for example, as required for higher battery capacity, as shown in FIGS. A battery electrode plate having a good intermittent shape can be formed without deteriorating the linearity at the end portion.

  Further, according to the third embodiment, there is no problem that the coating width is widened at the end as shown in FIGS. 15 (d) (3) and 16 (d) (3).

(Embodiment 4)
FIG. 8 shows an operation flow of the fourth embodiment.

  In the position changing unit 17 according to the second embodiment, as shown in FIGS. 5A and 5B, at T2 to T6, the upstream end HU at the slit die tip is in contact with the lower surface of the substrate 3, and the slit The position of the downstream end HL at the tip end of the die was the same in T1 to T6. On the other hand, in Embodiment 4, in T5 to T6, the downstream end HL and the base material 3 are changed by changing the angle of the slit die 1 relative to the base material 3 with the upstream end HU at the tip end of the slit die as a fulcrum. The only difference is that the gap is widened.

  FIG. 8A shows the behavior of the liquid pool in the vicinity of both edges in the width direction of the substrate 3, and FIG. 8B shows the behavior of the liquid pool in the center portion in the width direction.

  As described above, in addition to the operation flow of the second embodiment, the gap between the downstream end HL and the base material 3 at the slit die tip can be widened to promote the interruption of the liquid accumulation at the slit die discharge port. Therefore, the behavior that the timing at which the liquid pool is interrupted at the center in the width direction is delayed as compared with the vicinity of the end in the width direction can be further suppressed as compared with the second embodiment.

  In the case of Embodiment 3 where the gap between the upstream end HU and the downstream end HL at the slit die tip in Embodiment 4 and the supply stop timing of the coating liquid are qualitatively illustrated, This is the same as FIG.

  As a result, even in the case of a coating condition with a heavy coating weight or a thin base material 3 that is particularly prone to bend, for example, as required for higher battery capacity, as shown in FIGS. A battery electrode plate having a good intermittent shape can be formed without deteriorating the linearity at the end. Further, according to the present embodiment, there is no problem that the coating width at the end is widened as shown in FIGS. 15 (d) (3) and 16 (d) (3).

(Embodiment 5)
FIG. 9 shows a coating apparatus 8 according to a fifth embodiment that forms a coating film on both surfaces of a substrate 3 that runs horizontally.

  The coating device 8 transports the base material 3 supplied from an unwinder (not shown) in the order of the backup roll 18 to the transport roll 7, and the transport roll 7 and the subsequent transport are transported in the horizontal direction at a constant speed.

  The slit die 2 is installed facing the backup roll 18 with a space. The slit die 2 forms an upper surface coating portion 6 on the upper surface of the substrate 3. A tank 13, a pump 14, and a valve 15 are connected in series to the slit die 2 in the order described, and by supplying a constant amount of coating liquid, a fixed amount is discharged from the discharge port of the slit die 2 and has a uniform thickness. The upper surface coating portion 6 of the coating film is formed.

  Thereafter, the upper surface coating unit 6 is transported in the transport direction 9 by the backup roll 18 and the transport roll 7. Thereafter, the bottom surface of the base material 3 on which the top surface coating portion 6 before drying has already been formed is coated with the bottom surface by the slit die 1, the tank 10, the pump 11, and the valve 12 in the same configuration as in the first embodiment. A work part 4 is formed. In the base material 3 on which the upper surface coating part 6 and the lower surface coating part 4 are formed, the coating liquid applied through the drying device 16 is dried and collected by a winder (not shown). .

  The pump 11 and the pump 14 are preferably different systems, and the valve 12 and the valve 15 are preferably different systems. However, the tank 10 and the tank 13 may be the same system.

  Further, the valve 15 is branched into a pipe toward the slit die 2 and a pipe toward the tank 13, and the pump 14 is switched to the slit die 2 side by switching the valve 15 while feeding the coating liquid continuously and quantitatively. The coating liquid which heads is circulated to the tank 13 side, and the upper surface coating part 6 can be formed intermittently.

  Control of the gap between the upstream end HU and the downstream end HL with the base material 3 at the front end of the slit die 1 during intermittent coating is performed by the position changing unit 17 as described in the first to fourth embodiments. By changing the angle of the slit die 1 with respect to the substrate 3, the gap between the downstream end HL and the substrate 3 at the slit die tip is not changed, and the gap between the upstream end HU and the substrate 3 is narrowed, or The upstream end HU and the base material 3 are brought into contact with each other. Or after that, by changing the angle of the slit die relative to the substrate 3 with the upstream end HU of the slit die tip as a fulcrum, the gap between the slit die tip and the upstream end HU with the substrate 3 is not changed, By widening the gap between the downstream end HL and the base material 3, the linearity at the terminal end as shown in FIGS. 13 and 14 is not deteriorated, and a good intermittent shape as shown in FIG. 4 is obtained. A battery electrode plate can be formed. Furthermore, the problem that the coating width increases as shown in FIGS. 15 (d) (3) and 16 (d) (3) does not occur.

  In each of the above-described embodiments, the timing after the position changing unit 17 changes the gap between the upstream end HU of the slit die 1 tip and the base material 3 as shown in FIGS. Although supply of the coating liquid to the slit die 1 was stopped at Ts, as shown in FIG. 10 or FIG. 11, the coating was performed in the middle of changing the gap between the upstream end HU of the slit die tip portion and the base material 3. Even in the case where the position changing unit 17 is configured to stop the supply of the working liquid, a good terminal shape of the intermittent part is obtained similarly.

(Example 1)
In the first to fourth embodiments, a wet film thickness of 200 μm or 300 μm, a coating length of 1 m, a length of 15 cm of the uncoated portion 5, a coating speed of 35 m / min. Table 1 shows the results regarding the occurrence rate of defective coating liquid tailing in the lower surface coating portion 4 when 1000 m is applied.

  Here, in the case of a wet film thickness of 200 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 200 μm, and the upstream end HU base 3 narrowed intermittently The gap is 30 μm, the gap when contacting the substrate 3 is 0 μm, and when the gap between the downstream end HL of the slit die tip and the substrate 3 is widened after the supply of the coating liquid is stopped, the gap is 400 μm.

  In the case of a wet film thickness of 300 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 300 μm, and the base 3 of the upstream end HU of the slit die tip that is narrowed intermittently. When the contact with the base material 3 is 0 μm, and when the gap between the downstream end HL of the slit die tip and the base material 3 is widened after the supply of the coating liquid is stopped, the gap is 500 μm. did.

  Note that tailing tends to occur more easily as the coating thickness increases and the coating speed increases. Moreover, the thing exceeding the tailing length Y = 1.5mm of FIG. As a comparative example, Table 1 shows tailing defect ratios similarly performed in the related art shown in FIGS. 16 (b) and 16 (c).

Thus, with the downstream end HL of the slit die tip as a fulcrum, the gap between the downstream end HL of the slit die tip and the substrate 3 is not changed, and the base 3 of the upstream end HU of the slit die tip is After narrowing the gap, the supply of the coating liquid was stopped, or after that, the angle of the slit die with respect to the substrate 3 was changed with the upstream end HU of the tip end portion of the slit die as a fulcrum.

  By using a backup roll during horizontal transport at a constant speed by changing the gap between the downstream end HL and the base material 3 without changing the gap between the upstream end HU and the base material 3 at the slit die tip. Even when a coating film is formed on the lower surface of the base material 3 without being bent, it is likely to bend in the width direction of the base material during transportation due to the weight of the base material itself or the weight of the applied coating liquid. In particular, since the central portion in the width direction of the base material is conveyed in an unstable state in the vertical direction, the liquid pool is interrupted at the terminal end 4e and the base material 3 is not drawn into the behavior of trying to shrink due to surface tension. A battery electrode plate having a terminal shape with excellent linearity in the direction can be obtained.

(Example 2)
In the coating apparatus 8 of the fifth embodiment shown in FIG. 9 for forming the coating film on both surfaces of the substrate 3, all the examples except that the wet film thickness is set to 100 μm or 200 μm on the upper surface and the lower surface of the substrate 3 are all examples. Table 2 shows the results of the coating liquid tailing defect occurrence rate in the lower surface coating portion 4 when the same conditions as in Table 1 are used.

  Here, in the case of a wet film thickness of 100 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 100 μm, and the upstream end HU of the slit die tip that is narrowed intermittently When the gap between the base 3 and the base 3 is widened, the gap between the base 3 and the base 3 is 0 μm. Was set to 300 μm. When the wet film thickness is 200 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 200 μm, and the base of the upstream end HU of the slit die tip that is narrowed intermittently When the gap between the material 3 and the substrate 3 is increased to 20 μm, the gap when contacting the substrate 3 is 0 μm, and the gap between the downstream end HL of the slit die tip portion and the substrate 3 is widened after the supply of the coating liquid is stopped. The thickness was 400 μm.

Thus, with the downstream end HL of the slit die tip as a fulcrum, the gap between the downstream end HL of the slit die tip and the substrate 3 is not changed, and the base 3 of the upstream end HU of the slit die tip is After narrowing the gap, the supply of the coating liquid is stopped, or after that, the slit die tip is changed by changing the angle of the slit die with respect to the substrate 3 with the upstream end HU of the slit die tip as a fulcrum. In this case, the gap between the downstream end HL and the base material 3 is not changed, and the gap between the downstream end HL and the base material 3 is widened, so that the base material can be used without using a backup roll during horizontal conveyance at a constant speed. Even when a coating film is formed on both sides of the substrate 3, the substrate tends to bend in the width direction of the substrate during transportation due to the influence of the weight of the substrate itself and the weight of the applied coating liquid, and particularly the substrate. Carry with the center in the width direction unstable in the vertical direction As a result, the battery electrode plate having a terminal shape with good linearity in the width direction can be obtained without the base material 3 being drawn into the behavior in which the liquid reservoir is interrupted at the coating terminal portion and tends to shrink due to surface tension. it can.

(Example 3)
Table 3 shows the results of the coating liquid tailing failure occurrence rate in the lower surface coating portion 4 when all the conditions are the same as in Example 1 except that the coating speed is 50 m / min.

  Here, when the wet film thickness is 200 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 200 μm, and the upstream end HU of the slit die tip is narrowed intermittently. When the gap between the substrate 3 and the substrate 3 is 30 μm, the gap between the substrate 3 and the substrate 3 is 0 μm, and the gap between the downstream end HL of the tip end of the slit die and the substrate 3 is widened after the supply of the coating liquid is stopped. Was 400 μm. When the wet film thickness is 300 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 300 μm, and the base of the upstream end HU of the slit die tip is narrowed intermittently. When the gap between the material 3 and the substrate 3 is 30 μm, the gap when contacting the substrate 3 is 0 μm, and the gap between the downstream end HL of the tip end of the slit die and the substrate 3 is widened after the supply of the coating liquid is stopped. The thickness was 500 μm.

Thus, with the downstream end HL of the slit die tip as a fulcrum, the gap between the downstream end HL of the slit die tip and the substrate 3 is not changed, and the base 3 of the upstream end HU of the slit die tip is After narrowing the gap, the supply of the coating liquid is stopped, or after that, the slit die tip is changed by changing the angle of the slit die with respect to the substrate 3 with the upstream end HU of the slit die tip as a fulcrum. Without changing the gap between the upstream end HU and the base material 3 and widening the gap between the downstream end HL and the base material 3 without using a backup roll during horizontal conveyance at a constant speed. Even when the lower surface coating portion 4 is applied and formed on the lower surface of the substrate 3 at a high speed, the substrate tends to bend in the width direction during transportation due to the weight of the substrate itself and the weight of the coated coating liquid. And especially the center in the width direction of the base material The substrate 3 is not drawn into the behavior in which the liquid pool is interrupted at the coating end portion and is about to shrink due to the surface tension by being conveyed in an unstable state, and the end shape has good linearity in the width direction. A battery electrode plate can be obtained.

Example 4
Table 4 shows the results of the coating liquid tailing failure occurrence rate in the lower surface coating portion 4 when all the conditions were the same as in Example 2 except that the coating speed was 50 m / min.

  Here, in the case of a wet film thickness of 100 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 100 μm, and the upstream end HU of the slit die tip that is narrowed intermittently When the gap between the substrate 3 and the substrate 3 is increased to 20 μm, the gap when contacting the substrate is 0 μm, and the gap between the downstream end HL of the slit die tip and the substrate 3 is widened after the supply of the coating liquid is stopped. The thickness was 300 μm. When the wet film thickness is 200 μm, the gap between the upstream end HU and the downstream end HL of the slit die tip during coating is 200 μm, and the base of the upstream end HU of the slit die tip that is narrowed intermittently When the gap between the material 3 and the substrate 3 is increased to 20 μm, the gap when contacting the substrate 3 is 0 μm, and the gap between the downstream end HL of the slit die tip portion and the substrate 3 is widened after the supply of the coating liquid is stopped. The thickness was 400 μm.

Thus, with the downstream end HL of the slit die tip as a fulcrum, the gap between the downstream end HL of the slit die tip and the substrate 3 is not changed, and the base 3 of the upstream end HU of the slit die tip is After narrowing the gap, the supply of the coating liquid is stopped, or after that, the slit die tip is changed by changing the angle of the slit die 1 relative to the substrate 3 with the upstream end HU of the slit die tip as a fulcrum. The gap between the upstream end HU and the base material 3 at the part is not changed, and the gap between the downstream end HL and the base material 3 is widened, so that a base roll can be used without a backup roll during horizontal conveyance at a constant speed. Even when the lower surface coating portion 4 is applied and formed at high speed when the coating film is formed on both surfaces of the material 3, due to the influence of the weight of the base material itself and the weight of the coated coating liquid, The bending in the substrate width direction is likely to occur, and in particular Since the central portion in the width direction of the material is conveyed in an unstable state in the vertical direction, the liquid pool is interrupted at the coating end portion, and the base material 3 is not drawn into the behavior of trying to shrink due to the surface tension. A battery electrode plate having a good end shape can be obtained.

  Since the present invention can form a coating film intermittently on a substrate, it contributes particularly to an increase in capacity of a lithium ion secondary battery or the like.

DESCRIPTION OF SYMBOLS 1, 2 Slit die 3 Base material 4 Lower surface coating part 5 Uncoated part 6 Upper surface coating part 7 Conveyance roll 8 Coating apparatus 9 Substrate conveyance direction 10, 13 Tank 11, 14 Pump 12, 15 Valve 16 Drying Device 17 Position change unit 18 Backup roll HU Upstream end HL of the tip end of the slit die 1 Downstream end of the tip end of the slit die 1

Claims (10)

With respect to the traveling substrate, the discharge port is intermittently discharged by a slit die arranged opposite to the lower surface of the substrate to repeatedly form the lower surface coated portion and the uncoated portion, A method for producing a battery electrode plate, wherein the substrate coated with the lower surface coating portion is dried by passing through a drying device,
Before stopping the coating liquid from the discharge port of the slit die,
Start or complete the operation to narrow the gap between the upstream end of the slit die tip and the base material without changing the gap with the base material of the downstream end of the slit die tip,
After this, supply of the coating liquid to the slit die is stopped,
Manufacturing method of battery electrode plate. The substrate is
The method for producing a battery electrode plate according to claim 1, wherein an upper surface coating portion before drying is formed by applying a coating liquid on the upper surface before forming the lower surface coating portion. After stopping the supply of the coating liquid to the slit die,
Without changing the gap between the upstream end of the slit die and the base material, the gap between the downstream end of the slit die and the base material is widened.
The manufacturing method of the battery electrode plate of Claim 1 or 2. In a state in which the gap between the upstream end of the slit die and the base at the upstream end of the slit die is narrowed without changing the gap between the downstream end of the slit die and the base of the slit die, the tip of the slit die The upstream end of the substrate is brought into contact with the lower surface of the substrate.
The manufacturing method of the battery electrode plate in any one of Claims 1-3. By changing the angle of the slit die with respect to the base material, the gap with the base material is changed,
The manufacturing method of the battery electrode plate in any one of Claims 1-4. With respect to the traveling substrate, the discharge port is intermittently discharged by a slit die arranged opposite to the lower surface of the substrate to repeatedly form the lower surface coated portion and the uncoated portion, In the coating device for the battery electrode plate, the substrate coated with the lower surface coating portion is dried by passing through a drying device.
Provide a position changing unit that can individually change the gap between the base of the downstream end of the slit die and the base of the upstream end,
The front end of the slit die without changing the gap between the downstream end of the front end portion of the slit die and the base material before stopping the coating liquid from the discharge port of the slit die. The operation of narrowing the gap with the base material at the upstream end of the part is started or completed, and thereafter the supply of the coating liquid to the slit die is stopped.
Battery electrode plate coating equipment. The substrate is
Before forming the lower surface coating portion, provided a second slit die that forms the upper surface coating portion before drying by applying a coating liquid on the upper surface of the substrate,
The battery electrode plate coating apparatus according to claim 6. The position changing unit is
After stopping the supply of the coating liquid to the slit die,
Without changing the gap between the upstream end of the slit die and the base material, the gap between the downstream end of the slit die and the base material is widened.
The method for producing a battery electrode plate according to claim 6 or 7. The position changing unit is
In a state in which the gap between the upstream end of the slit die and the base at the upstream end of the slit die is narrowed without changing the gap between the downstream end of the slit die and the base of the slit die, the tip of the slit die The upstream end of the substrate is brought into contact with the lower surface of the substrate.
The coating apparatus of the battery electrode plate in any one of Claims 6-8. The position changing unit is
By changing the angle of the slit die with respect to the base material, the gap with the base material is changed,
The coating apparatus of the battery electrode plate in any one of Claims 6-9.