The present invention relates to a slot die coater adjusting device and a slot die coater adjusting system including the same, and more particularly, by moving the upper die of the slot die coater in the front-rear direction to adjust the distance between the upper and lower outlets of the slot die coater. It relates to a slot die coater adjusting device configured to be adjustable and an electrode active material coating system including the same.
[2]
This application is a priority claim application for Korean Patent Application No. 10-2018-0117142 filed on October 01, 2018, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
background
[3]
As technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source is rapidly increasing, and such secondary batteries essentially include an electrode assembly, which is a power generation element.
[4]
The electrode assembly has a form in which a positive electrode, a separator, and a negative electrode are stacked at least once, and the positive electrode and the negative electrode are prepared by coating and drying a positive electrode active material slurry and a negative electrode active material slurry on an electrode current collector made of aluminum foil and copper foil, respectively .
[5]
In order to make the charging/discharging characteristics of the secondary battery uniform, the positive electrode active material slurry and the negative electrode active material slurry should be uniformly coated on the current collector. For this purpose, a slot die coating process is typically performed.
[6]
1 is a schematic diagram for a slot die coating process is shown. Referring to FIG. 1 , the coating device 10 is configured to include a slot die coater 20 and a coating roll 40 from which the electrode active material slurry is discharged, and a current collector 50 while rotating the coating roll 40 . The active material is coated thereon.
[7]
The electrode active material slurry discharged from the slot die coater 20 is widely applied to one surface of the current collector 50 to form an electrode active material layer.
[8]
In some cases, the electrode active material slurry forming another layer may be additionally applied on the electrode active material layer forming one layer to form two electrode active material layers. In order to form the two electrode active material layers as described above, a slot die coater 70 including three die blocks 71 , 72 and 73 is typically used as shown in FIG. 2 . The slot die coater 70 of this type simultaneously discharges the electrode active material slurry through the two discharge ports 74 and 75 formed between adjacent die blocks, so that the electrode active material layer formed by the previously applied electrode active material slurry is on the An additional electrode active material slurry may be continuously applied to the .
[9]
However, in the process using the slot die coater 70, it is quite difficult to form each electrode active material layer to a desired thickness because it is necessary to use the electrode active material slurries simultaneously discharged from the different discharge ports 74 and 75. There is this.
[10]
In general, the thickness of each electrode active material layer is affected by the discharge amount of the electrode active material slurry through the discharge ports 74 and 75, and the discharge amount of the electrode active material slurry is determined by the distance between the respective die blocks 71, 72 and 73. Since it is greatly affected, in order to create a desired thickness, each die block (71, 72, 73) is disassembled and reassembled while experimentally performing the coating process several times to adjust the gap and check the discharge amount again is required to repeat.
[11]
However, in the conventional slot die coater 70, since the three die blocks 71, 72, 73 are sequentially coupled to each other to form two outlets 74 and 75, any one outlet 74 , 75) may require separation of all the die blocks 71, 72, and 73, and even if only one die block is separated, the positions of the remaining die blocks may be affected. 74, 75) is difficult to adjust individually.
[12]
Moreover, repeating the separation and reassembly of the die block and performing the test coating several times causes a delay in the process time, and also increases the consumption of the electrode active material slurry, which is a material, which greatly reduces the overall efficiency of the process. On the other hand, repeated disassembly and assembly may adversely affect the life of the slot die coater.
[13]
Accordingly, the development of a slot die coater having an improved structure that can solve this problem, that is, a slot die coater having a structure in which the distance between the upper and lower outlets can be adjusted by the relative movement of the upper and lower die, and such a slot die coater The development of a slot die coater adjusting device configured to control the distance between the upper coater and the lower coater is urgently required.
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[14]
The present invention was devised in consideration of the above problems, and the purpose of the present invention is to adjust the distance between the upper and lower outlets by sliding the upper die of the slot die coater along an inclined surface forming a predetermined angle with respect to the ground. do.
[15]
However, the technical problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.
means of solving the problem
[16]
A slot die coater adjusting device according to an embodiment of the present invention for solving the above-described problems, a lower die having a lower outlet for discharging a first active material slurry, and an upper portion having an upper outlet for discharging a second active material slurry In a slot die coater including a die, a slot die coater adjusting device for adjusting a distance between a lower discharge port and an upper discharge port by allowing the upper die to move, the slot die coater adjusting device being provided on one side and the other side in the longitudinal direction of the slot die coater, respectively, the upper a pressure block assembly secured to the die; an LM guide disposed under the pressure block assembly and connected to the pressure block assembly to guide the movement of the pressure unit; a driving unit providing power for the movement of the LM guide; and a reducer connected between the driving unit and the guide unit. includes
[17]
The slot die coater adjusting device may further include an inclined block disposed under the LM guide to support the LM guide.
[18]
The inclined block may have an upper surface inclined at a predetermined angle with respect to the ground to be parallel to opposing surfaces of the upper die and the lower die, respectively.
[19]
The LM guide may include a guide frame; a ball screw installed in the guide frame and connected to the reducer to receive power; and a moving block fastened to the ball screw to linearly move in the front-rear direction of the slot die coater according to the rotation of the ball screw. may include
[20]
The pressing block assembly may include: a cam follower fixed to the upper die; and a pressing block fixed on the moving block and having an insertion hole into which the cam follower is inserted. may include
[21]
The cam follower may include a rotation shaft fixed to the upper die; and a bearing in contact with an inner wall surface of the insertion hole and rotating about the rotation shaft. may include.
[22]
On the other hand, the electrode active material coating system according to an embodiment of the present invention for solving the above problems, a lower die having a lower outlet for discharging the first active material slurry and an upper outlet for discharging the second active material slurry a slot die coater including an upper die; a pressing block assembly provided on one side and the other side in the longitudinal direction of the slot die coater, respectively, and fixed to the upper die; an LM guide disposed under the pressure block assembly and connected to the pressure block assembly to guide the movement of the pressure unit; a driving unit providing power for the movement of the LM guide; and a reducer connected between the driving unit and the guide unit.
Effects of the Invention
[23]
According to an aspect of the present invention, the distance between the upper discharge port and the lower discharge port may be adjusted by sliding the upper die of the slot die coater along an inclined surface forming a predetermined angle with respect to the ground.
Brief description of the drawing
[24]
1 is a schematic diagram showing an example of using a slot die coater according to the prior art.
[25]
2 is a cross-sectional view showing the form of a slot die coater according to the prior art used in a multi-layer active material coating process.
[26]
3 is an overall perspective view showing an electrode active material coating system according to an embodiment of the present invention.
[27]
4 is a cross-sectional view illustrating a slot die coater applied to an electrode active material coating system according to an embodiment of the present invention.
[28]
5 is a partially enlarged view showing the rear surface of the electrode active material coating system and the slot die coater applied thereto according to an embodiment of the present invention.
[29]
FIG. 6 is a diagram illustrating a process of forming two active material layers on an electrode current collector using the slot die coater shown in FIG. 4 .
[30]
7 is a partial perspective view showing a part of the electrode active material coating system according to an embodiment of the present invention.
[31]
8 is a side view showing an electrode active material coating system according to an embodiment of the present invention.
Modes for carrying out the invention
[32]
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that it can be defined, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that there may be equivalents and variations.
[33]
Hereinafter, an electrode active material coating system according to an embodiment of the present invention will be described with reference to FIG. 3 .
[34]
3 is an overall perspective view showing an electrode active material coating system according to an embodiment of the present invention.
[35]
Referring to FIG. 3 , the electrode active material coating system according to an embodiment of the present invention includes a slot die coater 100 and a slot die coater adjusting device 200 .
[36]
The slot die coater 100 forms an electrode active material layer by coating an electrode active material slurry on an electrode current collector. The slot die coater 100 has a structure capable of discharging the electrode active material slurry through a pair of outlets formed in the lower die 110 and the upper die 120 , whereby two electrode active material layers are disposed on the electrode current collector. can form. The specific structure and function of the slot die coater 100 according to the present invention will be described later in detail with reference to FIGS. 4 to 6 .
[37]
The slot die coater adjusting device 200 is a device configured to adjust the distance between a pair of outlets formed in the slot die coater 100 , and includes a base block 210 , an inclined block 220 , and an LM guide (Linear). motion guide) 230 , the pressing block assembly 240 , a servo motor 250 , and a reducer 260 may be implemented.
[38]
The base block 210 is provided with a pair on one side and the other side in the longitudinal direction (Y-axis direction in FIG. 3) of the slot die coater 100, and is disposed under the inclined block 220 to form the inclined block 220. support
[39]
The inclined block 220 is provided with a pair on one side and the other side in the longitudinal direction of the slot die coater 100 , and is disposed above the base block 210 . The inclined block 220 has an upper surface inclined at a predetermined angle with respect to the ground (XY plane in FIG. 3), and the upper surface inclination is the lower die 110 and the upper die of the slot die coater 100. Same as the opposite side of (120). That is, the upper surface of the inclined block 220 is formed in parallel with the sliding surface S (refer to FIG. 4 ) formed by the opposing surfaces of the lower die 110 and the upper die 120 of the slot die coater 100 .
[40]
The LM guide 230 is provided with a pair on one side and the other side in the longitudinal direction of the slot die coater 100 , and is seated on the upper surface of the inclined block 220 . The LM guide 230 receives the power generated from the servomotor 250 to guide the movement of the pressing block assembly 240 so that the pressing block assembly 240 moves along the arrow direction of FIG. 3 .
[41]
The pressing block assembly 240 is provided with a pair on one side and the other side in the longitudinal direction of the slot die coater 100 , and is disposed on the LM guide 230 . The pressing block assembly 240 is fixed on the moving block 233 provided in the LM guide 230 , and the movement of the moving block 233 receiving power generated from the servomotor 250 makes a linear motion. Accordingly, it moves in the direction of the arrow shown in FIG. 3 .
[42]
In addition, the pair of pressure block assemblies 240 are respectively fixed to one side and the other side in the longitudinal direction of the slot die coater 100 . More specifically, the pair of pressing block assemblies 240 are respectively fixed to one side and the other side of the upper die 110 . Accordingly, when the pressing block assembly 240 moves along the arrow direction shown in FIG. 3 , the upper die 110 also moves on the lower die 120 .
[43]
The servomotor 250 is provided with a pair on one side and the other side in the longitudinal direction of the slot die coater 100 , and is located further back than the LM guide 230 and the pressing block assembly 240 .
[44]
The servomotor 250 transmits a driving force to the moving block 233 of the LM guide 230 through the reducer 260, whereby the moving block 233 performs a linear motion along the arrow direction shown in FIG. make it possible The servomotor 250 is disposed to extend along a direction perpendicular to the LM guide 230 .
[45]
The reducer 260 is provided with a pair on one side and the other side in the longitudinal direction of the slot die coater 100, and has an approximately L-shape. The reducer 260 is connected between the LM guide 230 and the servomotor 250 to transmit the driving force generated from the servomotor 250 to the LM guide 230 so that the moving block 233 can move.
[46]
The speed reducer 260 applies the force transmitted along the direction perpendicular to the upper surface of the inclined block 220 by the servo motor 250 in a direction perpendicular thereto, that is, in a direction parallel to the upper surface of the inclined block 220 . makes the conversion In addition, the reducer 260 transmits a force greater than the force provided by the servomotor 250 to the moving block 233 of the LM guide 230 through an appropriate gear ratio, and It enables fine movement of the moving block 233 .
[47]
On the other hand, the servomotor 250 is disposed more rearward than the LM guide 230 and the pressure block assembly 240 and the reducer 260 connects between the LM guide 230 and the pressure block assembly 240, The servomotor 250 along the direction (parallel to the X-axis of FIG. 3 ) from the rear surface of the slot die coater 100 in which the first fixing part 130 and the second fixing part 140 are formed toward the opposite surface, the front surface ), the reducer 260 and the LM guide 230 are arranged in order.
[48]
A specific structure for each component constituting the slot die coater adjusting device 200 and a specific function of the slot die coater adjusting device 200 will be described later in detail with reference to FIGS. 7 and 8 .
[49]
Next, the slot die coater 100 according to an embodiment of the present invention will be described in detail with reference to FIGS. 4 to 6 .
[50]
4 is a cross-sectional view showing a slot die coater applied to an electrode active material coating system according to an embodiment of the present invention, and FIG. 5 is a rear surface of a slot die coater applied thereto and an electrode active material coating system according to an embodiment of the present invention. is a partially enlarged view showing, and FIG. 6 is a view showing a process of forming two active material layers on an electrode current collector using the slot die coater shown in FIG. 4 .
[51]
4 to 6 , the slot die coater 100 includes a lower die 110 having a lower outlet 110A and an upper die 120 having an upper outlet 120A.
[52]
The lower die 110 includes a first die block 111 and a second die block 112 disposed on the first die block 111 . The first die block 111 may include a first active material slurry receiving part G1 formed in a groove shape having a predetermined depth on a surface facing the second die block 112 . The first active material slurry receiving part G1 may be connected to an active material slurry supply chamber (not shown) installed outside to continuously receive the first active material slurry. Also, the first active material slurry receiving part G1 may include an active material slurry supply port communicating with the active material slurry supply chamber.
[53]
When the first active material slurry is filled in the first active material slurry accommodating part G1 according to the supply of the first active material slurry by the active material slurry supply chamber, the first active material slurry is transferred to the first die block 111 and the second die It is discharged to the outside through the lower discharge port (110A) formed by the combination of the block (112).
[54]
The upper die 120 includes a third die block 121 and a fourth die block 122 disposed on the third die block 121 . The third die block 121 may include a second active material slurry receiving part G2 formed in a groove shape having a predetermined depth on a surface facing the fourth die block 122 . The second active material slurry receiving part G2 may be connected to an externally installed active material slurry supply chamber to continuously receive the second active material slurry. Also, the second active material slurry receiving part G2 may include an active material slurry supply port communicating with the active material slurry supply chamber.
[55]
When the second active material slurry is filled in the second active material slurry accommodating part G2 according to the supply of the second active material slurry by the active material slurry supply chamber, the second active material slurry is transferred to the third die block 121 and the fourth die. It is discharged to the outside through the upper discharge port (120A) formed by the combination of the block (122).
[56]
Opposing surfaces of the lower die 110 and the upper die 120 are inclined at a predetermined angle with the ground. That is, the opposing surfaces of the lower die 110 and the upper die 120 form a sliding surface S inclined with respect to the ground at a predetermined angle, and the upper die 120 slides on the lower die 110 . It moves forward or backward along a direction inclined at a predetermined angle with respect to the ground along the surface S.
[57]
Here, the front means the direction in which the outlets 110A and 120A of the slot die coater 100 are formed, and the rear means the opposite direction.
[58]
Meanwhile, the slot die coater 100 may further include a first fixing part 130 and a second fixing part 140 provided on a rear surface thereof. The first fixing unit 130 is provided with at least one pair to fasten the first die block 111 and the second die block 112 , and also to attach the third die block 121 and the fourth die block 122 . fasten
[59]
The second fixing part 140 is installed with a certain level of assembly tolerance (in the range of about 300 μm to 500 μm) in consideration of the fact that the upper die 120 must move forward or backward on the lower die 110 . .
[60]
That is, as will be described later, the upper die 120 is moved forward or backward along the sliding surface S on the lower die 110 by the movement of the moving block 233 (see FIG. 3 ) in the arrow direction. , the second fixing part 140 is to be fixed so that movement of a certain level or more does not occur between the lower die 110 and the upper die 120, but to allow fine movement due to assembly tolerance.
[61]
Referring to FIG. 6 , in this way, the upper die 120 moves forward or backward along the sliding surface S on the lower die 110 to provide a gap between the first outlet 110A and the second outlet 120A. can be formed.
[62]
In particular, when the upper die 120 is moved rearward in a state in which the lower die 110 and the upper die 120 are matched, the second outlet 120A is positioned more rearward than the first outlet 110A. , a first active material layer (A1) is first formed on the electrode current collector (E) wound on the coating roll (R), and a second active material layer (A2) may be formed thereon.
[63]
At this time, the moving distance of the upper die 120 is set in consideration of the thickness of the stacked second active material layer A2 , whereby the second active material layer A2 is stably formed on the first active material layer A1 . can be stacked.
[64]
Next, each component constituting the slot die coater adjusting apparatus 200 according to an embodiment of the present invention will be described in detail with reference to FIGS. 7 and 8 along with FIG. 4 .
[65]
Figure 7 is a partial perspective view showing a part of the electrode active material coating system according to an embodiment of the present invention, Figure 8 is a side view showing the electrode active material coating system according to an embodiment of the present invention.
[66]
Referring to FIGS. 7 and 8 together with FIG. 4 , the slot die coater adjusting device according to an embodiment of the present invention is a device configured to adjust the distance between a pair of outlets formed in the slot die coater 100. , a base block 210 , an inclined block 220 , an LM guide (Linear motion guide) 230 , a pressing block assembly 240 , a servo motor 250 , and a reducer 260 may be included. .
[67]
The base block 210, as described above, is disposed under the inclined block 220 to support the inclined block 220. This base block 210 is omitted and the inclined block 220 is adjusted in size. It is also possible to allow the pressing block assembly 240 to be disposed at a height corresponding to the upper die 120 .
[68]
As described above, the inclined block 220 has a structure in which its upper surface is parallel to the sliding surface S (see FIG. 4 ) of the slot die coater 100 . Due to this, according to the linear motion of the moving block 233 provided in the LM guide 230 seated on the upper surface of the inclined block 220, the upper die 120 smoothly moves in the front-rear direction along the sliding surface S. be able to move
[69]
The LM guide 230 includes a guide frame 231 seated on the upper surface of the inclined block 220 , a ball screw 232 installed in the guide frame 231 , and at least one movement coupled to the ball screw 232 . block 233 .
[70]
The ball screw 232 is positioned inside the guide frame 231 and is fastened to the guide frame 231 to rotate. The ball screw 232 is connected to the drive shaft 261 of the reducer 260 to be described later and rotates together as the drive shaft 261 of the reducer 260 rotates by the power transmitted from the servomotor 250 .
[71]
The ball screw 232 has a thread formed on at least a portion of its surface, and the moving block 233 is fastened to the threaded portion. A screw thread having a shape corresponding to the screw thread formed on the ball screw 232 is formed on the inner surface of the moving block 233 . Accordingly, when the ball screw 232 is rotated by the power transmitted through the servomotor 250 and the reducer 260, the moving block 233 linearly moves forward or backward along the arrow direction shown in FIG. do.
[72]
The pressing block assembly 240 includes at least one cam follower 241 coupled to a side surface of the upper die 120 of the slot die coater 100 and a moving block 233 of the LM guide 230 . and a pressing block 243 fixed on the upper die 120 to move the upper die 120 by applying a force to the cam follower 241 according to the movement of the moving block 233 .
[73]
The cam follower 241 includes a rotation shaft 241a coupled to the side surface of the upper die 120 and a bearing 241b rotating around the rotation shaft 241a.
[74]
The pressing block 243 has an insertion hole 243a having a size corresponding to the bearing 241b so that the cam follower 241 can be inserted thereinto. Accordingly, the bearing 241b is inserted into the insertion hole 243a and rotates while in contact with the inner wall surface of the insertion hole 243a according to the movement of the pressing block 243 . Due to the rotational movement of the bearing 241b, the forward and backward movement of the upper die 120 according to the movement of the pressing block 243 may be smoothly performed.
[75]
The direction of movement of the moving block 233 and the pressing block 243 and the direction of movement of the upper die 120 may not perfectly coincide with each other due to minute design tolerances and/or assembly tolerances of each part, in this case There may be a problem in that the parts are worn due to friction between the parts in contact with each other and the force is not transmitted smoothly.
[76]
That is, a slight difference may occur between the inclination of the upper surface of the inclined block 220 and the inclination of the sliding surface S of the slot die coater 100, and the movement of the moving block 233 is indicated by the arrow shown in FIG. It may not be completely consistent with the direction.
[77]
However, in the case of the slot die coater adjusting device 200 according to the present invention, the cam follower 241 to which the bearing 241b is applied is not directly fixed to the pressing block 243 on the upper die 120, but the upper die ( 120) and having a structure to move the bearing 241b of the cam follower 241 by pushing the pressing block 243 to prevent such a problem from occurring.
[78]
That is, when the inner wall surface of the insertion hole 243a applies a force to the bearing 241b, the direction of movement of the pressing block 243 is not formed in a direction completely parallel to the direction of the arrow shown in FIG. 7, but the bearing ( According to the rotational movement of 241b), the pressing block 243 can smoothly move in all directions within the tolerance range.
[79]
In the above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited thereto and will be described below with the technical idea of ​​the present invention by those of ordinary skill in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims.

Claims
[Claim 1]
A slot die coater including a lower die having a lower outlet for discharging a first active material slurry and an upper die having an upper outlet for discharging a second active material slurry, wherein the upper die moves between the lower outlet and the upper outlet A slot die coater adjusting device for adjusting a distance, comprising: a pressing block assembly provided on one side and the other side in a longitudinal direction of the slot die coater, respectively, and fixed to the upper die; an LM guide disposed under the pressure block assembly and connected to the pressure block assembly to guide the movement of the pressure unit; a driving unit providing power for the movement of the LM guide; and a reducer connected between the driving unit and the guide unit. A slot die coater adjustment device comprising a.
[Claim 2]
The slot die coater adjusting device according to claim 1, wherein the slot die coater adjusting device further comprises an inclined block disposed under the LM guide to support the LM guide.
[Claim 3]
[Claim 3] The slot die coater adjusting apparatus according to claim 2, wherein the inclined block has an upper surface inclined at a predetermined angle with respect to the ground so as to be parallel to opposite surfaces of the upper die and the lower die.
[Claim 4]
According to claim 1, The LM guide, a guide frame; a ball screw installed in the guide frame and connected to the reducer to receive power; and a moving block fastened to the ball screw to linearly move in the front-rear direction of the slot die coater according to the rotation of the ball screw. Slot die coater adjustment device comprising a.
[Claim 5]
5. The apparatus of claim 4, wherein the pressure block assembly comprises: a cam follower fixed to the upper die; and a pressing block fixed on the moving block and having an insertion hole into which the cam follower is inserted. Slot die coater adjustment device comprising a.
[Claim 6]
6. The method of claim 5, wherein the cam follower comprises: a rotation shaft fixed to the upper die; and a bearing in contact with an inner wall surface of the insertion hole and rotating about the rotation shaft. Slot die coater adjustment device comprising a.
[Claim 7]
a slot die coater including a lower die having a lower outlet for discharging the first active material slurry and an upper die having an upper outlet through which the second active material slurry is discharged; a pressing block assembly provided on one side and the other side in the longitudinal direction of the slot die coater, respectively, and fixed to the upper die; an LM guide disposed under the pressure block assembly and connected to the pressure block assembly to guide the movement of the pressure unit; a driving unit providing power for the movement of the LM guide; and a reducer connected between the driving unit and the guide unit. Electrode active material coating system comprising a.
[Claim 8]
The electrode active material coating system according to claim 7, wherein the electrode active material coating system further comprises an inclined block disposed under the LM guide to support the LM guide.
[Claim 9]
The electrode active material coating system according to claim 8, wherein the inclined block has an upper surface inclined at a predetermined angle with respect to the ground to be parallel to opposite surfaces of the upper die and the lower die, respectively.
[Claim 10]
The method according to claim 7, wherein the LM guide comprises: a guide frame; a ball screw installed in the guide frame and connected to the reducer to receive power; and a moving block fastened to the ball screw to linearly move in the front-rear direction of the slot die coater according to the rotation of the ball screw. Electrode active material coating system comprising a.
[Claim 11]
11. The apparatus of claim 10, wherein the pressure block assembly comprises: a cam follower secured to the upper die; and a pressing block fixed on the moving block and having an insertion hole into which the cam follower is inserted. Electrode active material coating system comprising a.
[Claim 12]
12. The method of claim 11, wherein the cam follower comprises: a rotation shaft fixed to the upper die; and a bearing in contact with an inner wall of the insertion hole and rotating about the rotation shaft. Electrode active material coating system comprising a.