KR20010108720A - Method and device for intermittent coating - Google Patents

Abstract

The present invention relates to an intermittent coating method and an apparatus used therein, wherein the coating amount is not increased locally at the end of the coating section, and the thickness can be uniformly maintained at high density throughout the coating section. ) And the C roll (1) on the C roll (1) controlled by a state in which the distance between the controller (4) and the C roll (1) is large, while switching the distance between the C roll (1) in large and small steps at an appropriate time interval. The thick coating layer 6a is transferred and coated onto the base sheet 3 in a state where the C roll 1 and the B roll 2 are in contact with each other through the base sheet 3, and the regulator 4 and C The gap between the C roll 1 and the B roll 2 is adjusted at a timing at which the thin coating layer 6c on the C roll 1 controlled by the state in which the gap with the roll 1 is small reaches the transfer position. It is characterized in that the paint is not opened and the coating on the base sheet (3).

Description

Intermittent painting method and apparatus used for it {METHOD AND DEVICE FOR INTERMITTENT COATING}

The present invention relates to a method and apparatus for coating a slurry-like coating material on a long length of a base sheet to a certain thickness, in particular an intermittent coating method for alternately forming a coating section and a non-painting section of a predetermined length for the base sheet and To the device.

For example, in mass production of spiral electrode type lithium batteries, the following intermittent coating techniques are required. A strip-shaped hoop material of copper foil or aluminum foil serving as a current collector of a battery is a base sheet, and a slurry binder mainly composed of an electrode active material is a coating material. For example, a 30 cm section of the base sheet is painted with a constant thickness, and then a 5 cm section is alternately formed with a predetermined length of the coating section and a non-painting section so as not to apply the coating at all. .

When performing such an intermittent coating, there is the following method using the coating apparatus called a reverse roll coater as shown in FIG.

In Fig. 7, the coating roll 1 (hereinafter referred to as C roll) is rotated at a predetermined speed in the direction of the arrow a, and the backing roll 2 (hereinafter referred to as B roll) is made of the C roll 1 and both rolls. In contact, it contacts with the base material sheet 3, and rotates to the opposite direction to the C roll 1 (arrow b direction). The base sheet 3 travels along the B roll 2 in the direction of the arrow c, and passes between the C roll 1 and the B roll 2.

In addition, a regulator called a doctor roll 4 (hereinafter referred to as a D roll) is fixedly installed (not rotated) above the C roll 1, and is disposed between the C roll 1 and the D roll 4. The predetermined interval is maintained. The paint 6 accumulated on the hopper 5 is attached to the circumferential surface of the C roll 1, and is coated on the base sheet 3 by passing through the minimum gap between the C roll 1 and the D roll 4. The coating material 6 is controlled by the adhesion amount (thickness) corresponding to the space | interval.

The paint layer 6a controlled to a predetermined thickness by the distance between the C roll 1 and the D roll 4 allows the base sheet 3 to pass between the C rolls 1 along the B roll 2. At this time, transfer coating is performed on the base sheet 3 side. Thereby, the coating layer 6b of the constant thickness controlled on the base sheet 3 is continuously coated.

In order to form an unpainted section intermittently, an actuating mechanism in which the B roll 2 is moved in parallel with the rotational axis in the orthogonal direction is laid, and it is displaced in the direction of the arrow d at regular intervals, and is separated from the C roll 1 largely. In the roll 1, the coating layer 6a is not transferred to the base sheet 3. After the predetermined time, the B roll 2 is displaced in the direction of the arrow e to return to its original position, and the coating layer 6a on the C roll 1 is transferred to the base sheet 3. The above operation can be repeated to execute the above-described intermittent coating.

However, in the conventional intermittent coating method described above, there is a problem in that the thickness of the coating layer 6b of the coating section cannot be controlled with high precision. The cause lies in the movement of the B roll 2 when moving from the painting process to the unpainting process. The coating amount of the coating material 6 onto the base sheet 3 is basically based on the distance between the C roll 1 and the D roll 4 and the rotational speed of the C roll 1 and B roll 2. It is controlled by. However, in the transient state of the movement in which the B roll 2 is separated from the C roll 1 (movement in the direction of the arrow d), the C roll just before the trace of the paint layer 6b on the substrate sheet 3 is completely broken. Guided by the B roll 2 separated from (1), the coating layer 6b bulges, and is coated on the base sheet 3. As a result, the edge thickness of the coating layer 6b locally increases at the end of the paint section, leading to very undesirable results. For example, in the example of the mass production line of the spiral electrode type lithium battery, in the process of rolling the intermittent coated sheet-shaped electrode, local dropout of the binder is likely to occur at the thick edge at the end of the coating section of the coating layer 6b. The current collector which consists of thin metal foil of the part was locally excessively rolled, and it became easy to be broken. Moreover, in the process of winding a sheet-like electrode in a spiral shape with a separator, it is easy to shift and wind up because of the said large edge. All of these are the cause of disturbing smooth production. In addition, even after the battery is completed, the optimum balance of the electric capacity of the positive electrode and the negative electrode collapses in the enlarged edge portion, and the effective use of the active material is hindered, especially in a spiral lithium secondary battery. For example, in the case of the secondary battery, when there is a large edge portion only on the positive electrode side, the negative electrode capacity is relatively smaller than the positive electrode, and dendrite is likely to occur at the negative electrode side during charging of the battery. Then, short circuit between electrodes becomes a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and an object thereof is to prevent the coating amount from increasing locally at the end of a coating section, and to intermittently coat the coating to control the thickness with high accuracy over the entire coating section. A method and an apparatus used for the same are provided.

1 is a process chart showing the configuration and operation of an intermittent coating method and an apparatus used therein according to an embodiment of the present invention;

2 is a process chart showing the configuration and operation of an intermittent coating method and an apparatus used therein according to an embodiment of the present invention;

3 is a process chart showing the configuration and operation of an intermittent coating method and an apparatus used therein according to an embodiment of the present invention;

4 is a process chart showing the configuration and operation of an intermittent coating method and an apparatus used therein according to an embodiment of the present invention;

5 is a process chart showing the configuration and operation of an intermittent coating method and an apparatus used therein according to an embodiment of the present invention;

6 is a process chart showing the configuration and operation of an intermittent coating method and an apparatus used therein according to an embodiment of the present invention;

7 is an explanatory diagram of a conventional intermittent coating method.

* Explanation of symbols for main parts of the drawings

1: Coating Roll (C Roll) 2: Backing Roll (B Roll)

3: Base sheet 4: Dr.roll (regulator)

6: paint

Therefore, in the intermittent coating method of the present invention, a slurry-like paint is attached to a rotating coating roll (C roll), and the thickness of the paint on the C roll is adjusted to an amount corresponding to the above gap by a regulator maintaining the C roll and a predetermined interval. Control and rotate the backing roll (B roll) disposed in contact with the C roll through a long length base sheet in the opposite direction at the contact point between the C roll and both rolls, and simultaneously rotate the base sheet along the B roll. A method of transferring the coating layer on the C roll, the thickness of which is controlled by the regulator, to the base sheet to transfer the coating sheet to the base sheet by running the substrate, wherein the distance between the controller and the C roll is appropriately set at an appropriate time interval. At the same time, the thick paint layer on the C roll controlled by the state in which the gap between the controller and the C roll is large, and the C roll and the B roll are connected to each other through the base sheet. The C roll and the B at a timing set to transfer the coating onto the base sheet in a moist state, and the thin coating layer on the C roll controlled by the state in which the gap between the regulator and the C roll is small reaches the transfer position. The space | interval of a roll was opened large so that paint may not be transcribe | coated to the said base sheet.

In addition, the intermittent coating apparatus according to the present invention for carrying out the above method maintains a predetermined interval between the rotating C roll and the C roll, and the slurry-like paint is applied to the C roll at a thickness corresponding to the interval. An adjusting device to be attached, a B roll rotating in the opposite direction at the contact point between the C roll and both rolls while being contacted through the C roll and the long length base sheet, and the base sheet running along the B roll to both sides. A substrate supply mechanism for passing the roll between the rolls and transferring the coating layer on the C roll whose thickness is controlled by the controller to the base sheet; A switching mechanism and a synchronous operation having a predetermined phase difference from the operation of the operating mechanism, and switching the positional relationship between the C roll and the B roll to two stages of contact or non-contact through the base sheet. It is provided with a second operating mechanism.

Although it is the same as running in the point which removes B roll from said C roll and forms a unpainted section, the space | interval of a C roll and a regulator is also changed in order to form the unpainted section. To form an unpainted section, the distance between the C roll and the regulator is first made small, and the paint layer on the C roll is made very thin. At the same time as this thin paint layer reaches the transfer position to the base sheet, the B roll is removed from the C roll. As a result, the paint layer on the base sheet is broken, and the edges are swollen.

1 to 6 show an intermittent coating method and an apparatus used therein according to an embodiment of the present invention. The basic relationship between the C roll 1, the B roll 2, the base sheet 3, the D roll 4, the hopper 5, and the paint 6 is the same as the conventional one described above, and the C roll 1 The operation process in which the upper paint layer 6a is transferred to the base sheet 3 to form the paint layer 6b is basically the same.

The present invention shifts the B roll (2) with respect to the C roll (1) as shown by the arrow de to change the positional relationship between the C roll (1) and the B roll (2) in two stages of contact or non-contact. In addition, there is also an operating mechanism for shifting the distance between the C roll 1 and the D roll 4 in two stages by displacing the D roll 4 with respect to the C roll 1 as shown by the arrow fg. Doing.

In the process of forming the paint section, as shown in Figs. 1 and 2, the C roll 1 and the B roll 2 are contacted through the base sheet 3 so that the gap between the C roll 1 and the D roll 4 is It is set large. At this time, the thick paint layer 6a on the C roll 1 controlled at the interval between the C roll 1 and the D roll 4 is transferred to the base sheet 3 and coated with a constant thickness paint layer 6b. Becomes

In forming the unpainted section, first, as shown in FIG. 3, the D roll 4 is displaced in the direction of the arrow f to narrow the gap with the C roll 1. Thereby, the coating layer 6c on the C roll 1 whose thickness was controlled becomes very thin. At the time when the head of the thin paint layer 6c reaches the transfer position to the base sheet 3, the B roll 2 is displaced in the direction of the arrow d as shown in FIG. Then, at the transfer position, at the same time as the B roll 2 is separated from the C roll 1 at the same time as the thick paint layer 6a on the C roll 1 side is changed to the thin paint layer 6c, The trailing edge of the coating layer 6b on the base sheet 3 side is not broken and the edge is not thickened. Further, before this time point, the D roll 4 is displaced in the direction of the arrow g to return to the position where the distance from the original C roll 1 becomes large.

When time elapses from FIG. 4 to FIG. 5, a non-coated section of a predetermined length is formed. After that, when the thick paint layer 6a reaches the transfer position again, the B roll 2 is displaced in the direction of the arrow e and returns to a position where the gap with the original C roll 1 is small, and the C roll 1 The coating layer 6a on ()) is transferred to the base sheet 3, and the formation of the coating section is resumed. In addition, since the change of thickness is much smaller than that of the end of the coating section, the starting edge portion of this coating section is not a problem since the shape tends to have rounded edges (the thickness decreases gradually). . By repeating the above operations, the desired intermittent coating is executed.

As described in detail above, according to the intermittent coating method of the present invention and the apparatus used therein, the gap between the C roll and the regulator is reduced first to make the paint layer on the C roll very thin, and the thin paint layer is used as the base sheet. At about the same time as reaching the transfer position of B roll, B roll falls from C roll. As a result, the coating layer on the base sheet is not broken, and the end edge of the coating section does not swell as in the prior art. Therefore, it is possible to alternately form a coating section and a non-painting section of a certain thickness controlled with high accuracy on the base sheet.

Claims (2)

A slurry-like coating material is attached to a rotating coating roll, and the thickness of the coating sheet on the coating roll is controlled by an adjuster which maintains a predetermined interval with the coating roll in an amount corresponding to the interval, and the base sheet having a long length on the coating roll. While rotating the backing roll disposed in contact with the coating roll in the opposite direction at the contact point between the coating roll and both rolls, while running the base sheet along the backing roll to pass between the coating roll and the controller, In the method for transferring the coating layer on the coating roll of the controlled thickness on the base sheet, At the same time by switching the interval between the controller and the coating roll in a large and small step at an appropriate time interval, Transfer coating of the thick paint layer on the coating roll controlled by the state of the controller and the coating roll to the base sheet in a state in which the coating roll and the backing roll are in contact with each other through the base sheet, Opening the gap between the coating roll and the backing roll at a timing at which the thin coating layer on the coating roll controlled by the condition of the controller and the coating roll is small to reach the transfer position, An intermittent coating method, characterized in that not to be transferred. A regulator for attaching a slurry-like coating material to the coating roll at a thickness corresponding to the interval while maintaining a predetermined gap between the rotating coating roll and the coating roll; and the coating roll and the base sheet having a long length. The backing roll which rotates in the opposite direction at the contact between the coating roll and both rolls at the same time, and the base sheet is moved along the backing roll to pass the gap portion, the thickness controlled by the adjuster A substrate supply mechanism for transferring the coating layer on the coating roll onto the substrate sheet; An actuating mechanism for switching the interval between the controller and the coating roll in two stages at an appropriate time interval; And a second actuating mechanism having a predetermined phase difference from the operation of the actuating mechanism and synchronously shifting the positional relationship between the coating roll and the backing roll in two stages of contact or non-contact through the base sheet. Intermittent painting device characterized in that.